ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (17,478)
  • Other Sources  (685)
  • Chemistry  (16,079)
  • Polymer and Materials Science  (3,577)
  • Cell & Developmental Biology  (1,399)
  • ELECTRONICS AND ELECTRICAL ENGINEERING
  • METEOROLOGY AND CLIMATOLOGY
  • Pflanzenschädling
  • 1990-1994  (11,247)
  • 1940-1944  (977)
  • 1925-1929  (4,283)
  • 1920-1924  (1,656)
  • 1900-1904
  • 1991  (11,247)
  • 1949
  • 1947
  • 1942  (977)
  • 1929  (2,240)
  • 1928  (2,043)
  • 1922  (1,656)
Collection
  • Articles  (17,478)
  • Other Sources  (685)
Keywords
Years
  • 1990-1994  (11,247)
  • 1940-1944  (977)
  • 1925-1929  (4,283)
  • 1920-1924  (1,656)
  • 1900-1904
  • +
Year
  • 1
    Publication Date: 1991-10-25
    Description: The presence of clathrate hydrates in cometary ice has been suggested to account for anomalous gas release at large radial distances from the sun as well as the retention of volatiles in comets to elevated temperatures. However, how clathrate hydrates can form in low-pressure environments, such as in cold interstellar molecular clouds, in the outer reaches of the early solar nebula, or in cometary ices, has been poorly understood. Experiments performed with the use of a modified electron microscope demonstrate that during the warming of vapor-deposited amorphous ices in vacuo, clathrate hydrates can form by rearrangements in the solid state. Phase separations and microporous textures that are the result of these rearrangements may account for a variety of anomalous cometary phenomena.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Blake, D -- Allamandola, L -- Sandford, S -- Hudgins, D -- Freund, F -- New York, N.Y. -- Science. 1991 Oct 25;254:548-51.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Planetary Biology Branch, Ames Research Center, Moffett Field, CA 94035, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11538372" target="_blank"〉PubMed〈/a〉
    Keywords: Chemical Phenomena ; Chemistry ; Crystallography ; Earth (Planet) ; Hydrocarbons/chemistry ; Ice/*analysis ; *Meteoroids ; Microscopy, Electron ; *Solar System
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1991-07-12
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Baskin, Y -- New York, N.Y. -- Science. 1991 Jul 12;253(5016):140-2.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1853198" target="_blank"〉PubMed〈/a〉
    Keywords: *Academies and Institutes ; Biology ; California ; Chemical Phenomena ; Chemistry ; Research Support as Topic
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 1991-05-03
    Description: Immunochemistry has historically focused on the nature of antigenicity and antibody-antigen recognition. However, in the last 5 years, the field of immunochemistry has taken a new direction. With the aid of mechanistic and synthetic chemistry, the vast network of molecules and cells of the immune system has been tapped to produce antibodies with a new function--catalytic antibodies. Because antibodies can be generated that selectively bind almost any molecule of interest, this new technology offers the potential to tailor-make highly selective catalysts for applications in biology, chemistry, and medicine. In addition, catalytic antibodies provide fundamental insight into important aspects of biological catalysis, including the importance of transition-state stabilization, proximity effects, general acid and base catalysts, electrophilic and nucleophilic catalysis, and strain.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lerner, R A -- Benkovic, S J -- Schultz, P G -- New York, N.Y. -- Science. 1991 May 3;252(5006):659-67.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Scripps Research Institute, La Jolla, CA 92037.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2024118" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Antibodies/chemistry/immunology/metabolism ; Antibodies, Monoclonal/immunology/metabolism ; Antibody Specificity ; Antigens/chemistry/immunology/metabolism ; Binding Sites, Antibody ; *Catalysis ; Chemical Phenomena ; Chemistry ; Haptens ; Hydrogen-Ion Concentration ; Hydrolysis ; Metals ; Molecular Conformation ; Recombinant Proteins ; Thermodynamics ; Zinc
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2011-12-09
    Description: Microstrip ring resonators operating at 35 GHz were fabricated from laser ablated YBCO films deposited on lanthanum aluminate substrates. They were measured over a range of temperatures and their performances compared to identical resonators made of evaporated gold. Below 60 Kelvin the superconducting strip performed better than the gold, reaching an unloaded Q approximately 1.5 times that of gold at 25 K. A shift in the resonant frequency follows the form predicted by the London equations. The Phenomenological Loss Equivalence Method is applied to the ring resonator and the theoretically calculated Q values are compared to the experimental results.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Microwave Theory and Techniques (ISSN 0018-9480); 39; 1480-148
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2011-12-09
    Description: A chemical vapor deposition (CVD) process has been used to produce device structures of n- and p-type 6H-SiC epitaxial layers on commercially produced single-crystal 6H-SiC wafers. Mesa-style p-n junction diodes were successfully fabricated from these device structures using reactive ion etching, oxide passivation, and electrical contact metallization techniques. When tested in air, the 6H-SiC diodes displayed excellent rectification characteristics up to the highest temperature tested, 600 C. To observe avalanche breakdown of the p-n junction diodes, testing under a high-electrical-strength liquid was necessary. The avalanche breakdown voltage was 1000 V representing the highest reverse breakdown voltage to be reported for any CVD-grown SiC diode.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 59; 1770-177
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2011-12-09
    Description: Two new coplanar waveguide to rectangular waveguide couplers with coupling through a post and a slot are experimentally demonstrated. The couplers operate over the Ku-band transmission and X-band reception frequencies that are designated for satellite communications. The measured insertion loss and return loss are about 1 dB, respectively, for both couplers.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Electronics Letters (ISSN 0013-5194); 27; 856-858
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2011-08-24
    Description: A method to estimate raindrop size distribution (DSD) parameters from a combined Zm profile and path-integrated attenuation is shown, and a test result of the method using the data from an aircraft experiment is presented. The 'semi' dual-parameter (SDP) measurement is employed to estimate DSD parameters using the data obtained from an aircraft experiment conducted by Communications Research Laboratory, Tokyo, in conjunction with NASA. The validity of estimated DSD parameters is examined using measured Ka-band radar reflectivities. The estimated path-averaged N(0) is consistent with the Ka/X Ze ratio, and the use of estimated DSD shows excellent agreement between the rain rates estimated from the X-band and K-band Zes. The feasibility of estimating DSD parameters from space is confirmed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: In: International Conference on Radar Meteorology, 25th, Paris, France, June 24-28, 1991, Preprints (A93-37626 15-47); p. 384-387.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2011-08-24
    Description: In order to investigate the role of the drop size distribution (DSD) from a dual-wavelength airborne radar and to recover profiled rain rates, a procedure is described for the purpose of estimating the DSD. The method differs from previous approaches in that it provides 2n + 1 parameters of the profiled DSD (where n is the number of range gates) and it uses a recursive procedure beginning at the range gate near the surface progressing backwards toward the storm top. The method is argued to be useful both as a diagnostic tool and as a means by which more detailed information on the vertical structure of the precipitation can be obtained.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: In: International Conference on Radar Meteorology, 25th, Paris, France, June 24-28, 1991, Preprints (A93-37626 15-47); p. 380-383.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2011-08-24
    Description: Meteorological approaches to verification of space measurements of rainfall are examined; validation of Tropical Rainfall Measuring Mission (TRMM) observations is expected to depend significantly on ground-based radars. Two methods of comparison are initially contemplated. TRMM rainfall data over time periods of a month for large areas (500 x 500 km) are averaged and compared with similarly averaged ground truth measurements. Both the rainfall and height distribution data from TRMM are compared with the instantaneous values observed at one or more 'ground truth' stations and from airborne radar and radiometers as available.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: In: International Conference on Radar Meteorology, 25th, Paris, France, June 24-28, 1991, Preprints (A93-37626 15-47); p. 374-379.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2011-08-24
    Description: We describe the fabrication and characterization of superconductor/normal metal/superconductor (SNS) devices made with the high-temperature superconductor (HTS) YBa2Cu3O(7-x). Structures of YBa2Cu3O(7-x)/Au/Nb on c-axis-oriented YBa2Cu3O(7-x) were made in both sandwich and edge geometries in order to sample the HTS material both along and perpendicular to the conducting a-b planes. These devices display fairly ideal Josephson properties at 4.2 K. In addition, devices consisting of YBa2Cu3O(7-x)/YBa2Cu3O(y)/YBa2Cu3O(7-x), with a 'normal metal' layer of reduced transition temperature YBa2Cu3O(7-x) were fabricated and show a great deal of promise for applications near 77 K. Current-voltage characteristics like those of the Resistively-Shunted Junction model are observed, with strong response to 10 GHz radiation above 60 K.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: In: Superconductivity applications for infrared and microwave devices II; Proceedings of the Meeting, Orlando, FL, Apr. 4, 5, 1991 (A93-27243 09-33); p. 192-196.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Publication Date: 2011-08-24
    Description: Thin film low-pass microwave filters have been made with laser-ablated YBa2Cu3O(7-delta) (YBCO) deposited on LaAlO3 substrates, using a coplanar waveguide structure. The coplanar waveguide sections had dimensions suited for integrated circuits. Measured losses in liquid nitrogen were superior to the loss in a similar thin-film copper filter throughout the 0 to 9.5 GHz pass-band. A simple transmission-line model is adequate for filter design using YBCO films with repeatable characteristics. The measured filters demonstrate the performance of fully patterned YBCO after sealing in space-qualifiable hermetic packages. Five packaged filters of this design were delivered to the Naval Research Laboratory as candidates for space flight in the High Temperature Superconductivity Space Experiment.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: In: Superconductivity applications for infrared and microwave devices II; Proceedings of the Meeting, Orlando, FL, Apr. 4, 5, 1991 (A93-27243 09-33); p. 95-100.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Publication Date: 2011-08-24
    Description: The design of a 75-W, 59- to 64- GHz TWT with a predicted overall efficiency in excess of 40 percent is described. This intersatellite communications TWT, designated Model 961HA, employs a coupled-cavity slow-wave structure with a two-step velocity taper and an isotropic graphite multistage depressed collector (MDC). Because the RF efficiency of this TWT is less than 8 percent, an MDC design providing a very high collector efficiency was necessary to achieve the overall efficiency goal of 40 percent.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: ; : Computational meth
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Publication Date: 2011-08-24
    Description: The microphysical/dynamical nature and evolution of numerically simulated convective storms observed on July 11, 1986 during the Cooperative Huntsville Meteorological Experiments are investigated with the Goddard Cumulus Ensemble model. The model-simulated hydrometeor and radar reflectivity structure is verified with results derived from the multiparameter radar observations, which includes a description of the reflectivity, differential reflectivity, linear depolarization ratio, and hail signal for two thunderstorm cases analyzed by Fulton and Heymsfield (1990). Radar analysis shows the storm to split with the newer more vigorous cell in the SE quadrant. Echo tops are near 15 km while peak reflectivities exceed 50 dBZ. Preliminary model simulations likewise show a splitting storm with regeneration occurring on the SSE flank. Echo tops are around 14 km with peak reflectivities over 45 dBZ.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: In: International Conference on Radar Meteorology, 25th, Paris, France, June 24-28, 1991, Preprints (A93-37626 15-47); p. 706, 707.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Publication Date: 2011-08-24
    Description: The basic features of a new and improved bulk-microphysical parameterization capable of simulating the hydrometeor structure of convective systems in all types of large-scale environments (with minimal adjustment of coefficients) are studied. Reflectivities simulated from the model are compared with radar observations of an intense midlatitude convective system. Simulated reflectivities using the novel four-class ice scheme with a microphysical parameterization rain distribution at 105 min are illustrated. Preliminary results indicate that this new ice scheme works efficiently in simulating midlatitude continental storms.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: In: International Conference on Radar Meteorology, 25th, Paris, France, June 24-28, 1991, Preprints (A93-37626 15-47); p. 782-785.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Publication Date: 2011-08-24
    Description: A proposed Ka-band communications experiment between the Shuttle Orbiter and the Advanced Communications Technology Satellite (ACTS) is described. Monolithic Microwave Integrated Circuit (MMIC) technology is used in both the Orbiter and on the ground. A 25 dB gain circularly polarized phased array transmits low-bit-rate television to ground stations at the Johnson Space Center and the Lewis Research Center.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: In: Monolithic microwave integrated circuits for sensors, radar, and communications systems; Proceedings of the Meeting, Orlando, FL, Apr. 2-4, 1991 (A93-25776 09-33); p. 231-242.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Publication Date: 2011-08-24
    Description: Capabilities and limitations of MMIC phase shifter technology at microwave and millimeter wave frequencies are reviewed. MMIC-based phase arrays make it possible to integrate active elements at the array face, i.e., to incorporate transmit power amplifiers and/or low noise amplifiers at each antenna element. Active elements make it possible to increase power efficiency and reliability and provide graceful degradation. Monolithic integration of the various transmit/receive functions including phase shifting is considered to be feasible through at least the lower millimeter-wave frequency range (about 30-100 GHz). MMIC integration also allows more flexibility in array design including those that are intended for airborne conformal applications.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: In: Monolithic microwave integrated circuits for sensors, radar, and communications systems; Proceedings of the Meeting, Orlando, FL, Apr. 2-4, 1991 (A93-25776 09-33); p. 288-302.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Publication Date: 2011-08-24
    Description: Ka-band MMIC transmitter arrays are under development at NASA Jet Propulsion Laboratory for future deep space and ground communication needs. A high efficiency full aperture active antenna array is desired to demonstrate solid state array technology for future NASA missions. This paper reports on a 5 watt Ka-band phased array feed and a full aperture active array for a mobile terminal which are being developed to characterize the design tradeoffs and potential of solid state Ka-band MMIC array communication systems.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: In: Monolithic microwave integrated circuits for sensors, radar, and communications systems; Proceedings of the Meeting, Orlando, FL, Apr. 2-4, 1991 (A93-25776 09-33); p. 243-247.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Publication Date: 2011-08-24
    Description: Infrared radiance measurements by the GOES-6 satellite during April 1986 through April 1987 were used to characterize and identify distinct regimes of persistent large-scale cloudiness patterns over the Amazon Basin. It is suggested that the energetics of the tropical troposphere over the Amazon Basin can be directly related to the GOES large-scale cloudiness patterns. The geometry and persistence of the cloud patterns are influenced by shifts in general circulation features and are likely modulated by 4- to 5-day and 40- to 60-day waves. Diurnal forcing effects are more pronounced during weather regimes characterized by prominently clear skies over land areas.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: ; : Strong shock waves
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Publication Date: 2011-08-24
    Description: The study presents preliminary results from an airborne radar/radiometer experiment (Typhoon Experiment) which was conducted in the western Pacific Ocean during September 1990, with emphasis on the multiparameter radar results. One of the objectives of this experiment is to make radar/radiometer measurements over rain to support the algorithm development and science studies for the Tropical Rainfall Measuring Mission (TRMM) and the spaceborne weather sensors. The extremely high linear depolarization ratio value observed at the melting height is considered to be procured by the melting particle with large eccentricity. It is shown that the multiparameter airborne radar provides valuable information by distinguishing the hydrometeor particles of the rainfall.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: In: International Conference on Radar Meteorology, 25th, Paris, France, June 24-28, 1991, Preprints (A93-37626 15-47); p. 400-403.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Publication Date: 2011-08-24
    Description: Approaches for future 'mixed application' monolithic integrated circuits (ICs) employing optical receive/transmit, RF amplification and modulation and digital control functions are discussed. We focus on compatibility of the photonic component fabrication with conventional RF and digital IC technologies. Recent progress at Honeywell in integrating several parts of the desired RF/digital/photonic circuit integration suite required for construction of a future millimeter-wave optically-controlled phased-array element are illustrated.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: In: Monolithic microwave integrated circuits for sensors, radar, and communications systems; Proceedings of the Meeting, Orlando, FL, Apr. 2-4, 1991 (A93-25776 09-33); p. 223-230.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Publication Date: 2011-08-24
    Description: Recent advances in pseudomorphic HEMT MMIC (PMHEMT/MMIC) technology have made it the preferred candidate for high performance millimeter-wave components for phased array applications. This paper describes the development of PMHEMT/MMIC components at Ka-band and V-band. Specifically, the following PMHEMT/MMIC components will be described: power amplifiers at Ka-band; power amplifiers at V-band; and four-bit phase shifters at V-band. For the Ka-band amplifier, 125 mW output power with 5.5 dB gain and 21 percent power added efficiency at 2 dB compression point has been achieved. For the V-band amplifier, 112 mW output power with 6 dB gain and 26 percent power added efficiency has been achieved. And, for the V-band phase shifter, four-bit (45 deg steps) phase shifters with less than 8 dB insertion loss from 61 GHz to 63 GHz will be described.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: In: Monolithic microwave integrated circuits for sensors, radar, and communications systems; Proceedings of the Meeting, Orlando, FL, Apr. 2-4, 1991 (A93-25776 09-33); p. 184-192.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-24
    Description: Present processes of global climate change are reviewed. The processes determining global temperature are briefly described and the concept of effective temperature is elucidated. The greenhouse effect is examined, including the sources and sinks of greenhouse gases.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Publication Date: 2011-08-24
    Description: The Global Backscatter Experiment (GLOBE) goals require intensive study of the global climatology of atmospheric aerosol backscatter at IR wavelengths. Airborne and ground-based lidars have been developed to measure atmospheric backscatter profiles at CO2 laser wavelengths. Descriptions of the calibration techniques and selected measurement results are presented.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: In: Laser radar VI; Proceedings of the Meeting, Los Angeles, CA, Jan. 23-25, 1991 (A93-17851 05-36); p. 139-146.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Publication Date: 2011-12-09
    Description: Microwave transmission measurements through YBa2Cu3O(7-delta) (YBCO) high-transition-temperature superconducting thin films on lanthanum aluminate (LaAlO3) have been performed in a coaxial line at 10 GHz. LaAlO3 substrates were ultrasonically machined into washer-shaped discs, polished, and coated with laser-ablated YBCO. These samples were mounted in a 50-ohm coaxial air line to form a short circuit. The power transmitted through the films as a function of temperature was used to calculate the normal state conductivity and the magnetic penetration depth for the films.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Applied Superconductivity (ISSN 1051-8223); 1; 178-180
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2006-06-13
    Description: The goals of this program are to develop custom microcircuit technology, also known as Application Specific Integrated Circuit (ASIC) technology, for use in flight and ground programs. Supporting this effort are activities to investigate the effects of the space environment, and particularly ionizing radiation, on microcircuits and to develop a space qualification methodology. Another aspect of the program emphasizes innovative applications of custom microcircuit technology to image and signal processing and communications.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Center for Space Microelectronics Technology; p 83-87
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Publication Date: 2011-08-24
    Description: Phase distortions in optical systems induced by atmospheric turbulence are investigated with the use of Zernike polynominal decompositions. An analytic solution for the variances of the Zernike coefficients is found for the case of Kolmogorov turbulence with a finite outer-scale length. It is shown that the effect of finite outer scale is to attenuate low-order Zernike components, even when the outer-scale length is much larger than the optical aperture. Effects are investigated for constant outer-scale size and for height-dependent outer scales. It is found that seeing effects on large telescopes are dependent more on the magnitude of the outer scale than on the shape of the outer-scale vertical profile.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Optical Society of America, Journal, A: Optics and Image Science (ISSN 0740-3232); 8; 1568-157
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Publication Date: 2011-08-24
    Description: A novel and unique ocean-surface wind data-set has been derived by combining the Defense Meteorological Satellite Program Special Sensor Microwave Imager data with additional conventional data. The variational analysis used generates a gridded surface wind analysis that minimizes an objective function measuring the misfit of the analysis to the background, the data, and certain a priori constraints. In the present case, the European Center for Medium-Range Weather Forecasts surface-wind analysis is used as the background.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: EOS (ISSN 0096-3941); 72; 201
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Publication Date: 2011-08-24
    Description: Observational evidence of rather large period waves (23-60 d) in the troposphere/stratosphere, particularly during the winter months, is presented. Wind data collected on a regular basis employing high-altitude balloons and meteorological rockets over the past few years are used. Maximum entropy methods applied to the time series of zonal wind data indicate the presence of 23-60-waves more prominently than shorter-period waves. The waves have substantial amplitudes in the stratosphere and lower mesosphere, often larger than those noted in the troposphere. The mean zonal wind in the troposphere (5-15 km altitude) during December, January, and February exhibits the presence of strong westerlies at latitudes between 8 and 21 deg N.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Atmospheric and Terrestrial Physics (ISSN 0021-9169); 53; 1181-119
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Publication Date: 2011-08-24
    Description: This study presents a nested-grid nonhydrostatic and elastic model using a terrain-following coordinate transformation as well as a unique application of grid-nesting techniques to the time-splitting elastic model. A simulation of the 10-m-high Witch of Agnesi Mountain provides the control to test this new model. The results show that the model produces the same solution as that derived from a simple linear analytic model. It is demonstrated that the new nested-grid model improves model resolution without resorting to the costly method of placing a fine-resolution grid over the entire domain. Since the wave reflection from the boundaries of the fine-grid model is well controlled, the boundary of the nested fine-grid model can be located even at the wave-active region. The model can be used to simulate various weather systems in which scale interactions are important.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 119; 2852-286
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Publication Date: 2011-08-24
    Description: Results are presented of observations of a waterspout funnel and spray ring performed under a cumulus line over the Great Salt Lake for about 5 min shortly after sunrise on June 26, 1985. These observations were used as the basis for a study of the initiation and evolution of waterspouts through a series of numerical experiments at two scales, that of a cloud and a waterspout. The cloud scale was simulated using an improved Goddard-Schlesinger model with nearby Salt Lake City soundings. Results showed that for each mode of cloud initiation, the vortex that started at the anticyclonic center grew faster than those started at other centers. This result strongly suggests that the cloud vorticity was important in its initiation. The greatest azimuthal speed for the bubble-initiated cloud was 11 m/s, when the vortex model was started at 28-min cloud time with time-varying boundary conditions, whereas it was 21 m/s when started at 12 min in the line-initiated cloud. The results support the hypothesis that, at least in some circumstances, cloud processes alone can produce waterspouts in the absence of external vorticity sources such as surface convergence lines or other shear features.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 119; 2741-277
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Publication Date: 2011-08-24
    Description: Post-irradiation effects (PIE) ranging from normal recovery to catastrophic failure have been observed in integrated circuits during the PIE period. Data presented show failure due to rebound after a 10 krad(Si) dose. In particular, five device types are investigated with varying PIE response. Special attention has been given to the HI1-507A analog multiplexer because its PIE response is extreme. X-ray diffraction has been uniquely employed to measure physical stress in the HI1-507A metallization. An attempt has been made to show a relationship between stress relaxation and radiation effects. All data presented support the current MIL-STD Method 1019.4 but demonstrate the importance of performing PIE measurements, even when mission doses are as low as 10 krad(Si).
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 38; 1584-158
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Publication Date: 2011-08-24
    Description: A methodology is described for predicting the SEU susceptibility of a standard-cell D-latch using an alpha-particle sensitive SRAM, SPICE critical charge simulation results, and alpha-particle interaction physics. Measurements were made on a 1.6-micron n-well CMOS 4-kb test SRAM irradiated with an Am-241 alpha-particle source. A collection depth of 6.09 micron was determined using these results and TRIM computer code. Using this collection depth and SPICE derived critical charge results on the latch design, an LET threshold of 34 MeV sq cm/mg was predicted. Heavy ion tests were then performed on the latch and an LET threshold of 41 MeV sq cm/mg was determined.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 38; 1486-149
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Publication Date: 2011-08-24
    Description: JPL and the Aerospace Corporation have collected a fourth set of heavy ion single event effects (SEE) test data. Trends in SEE susceptibility (including soft errors and latchup) for state-of-the-art parts are displayed. All data are conveniently divided into two tables: one for MOS devices, and one for a shorter list of recently tested bipolar devices. In addition, a new table of data for latchup tests only (invariably CMOS processes) is given.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 38; 1529-153
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Publication Date: 2011-08-24
    Description: The authors report on the direct detection capabilities of resonant tunneling diodes in the 10-100 GHz range. An open circuit voltage sensitivity of 1750 mV/mW (in Ka-band) was measured. This is higher than the sensitivity of comparatively based commercially available solid-state detectors. The detector properties are a strong function of diode bias and the measured tangential signal sensitivity (-32 dBm at Ka-band with 1-MHz bandwidth) and the dynamic range (25 dB) of the diode are smaller compared to other solid-state detectors.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Microwave Theory and Techniques (ISSN 0018-9480); 39; 1876-188
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Publication Date: 2011-08-24
    Description: The first InGaAs/InP charge-coupled device is demonstrated, exhibiting a charge transfer efficiency (CTE) of 0.98 at 13 MHz and 1 GHz. Cooling the device improves the CTE to greater than 0.99 at 13-MHz clock frequency. The 0.76-eV In(0.53)Ga(0.47)As bandgap makes this structure applicable to direct-detection short-wavelength infrared imagers.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Electron Device Letters (ISSN 0741-3106); 12; 688-690
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Publication Date: 2011-08-24
    Description: A procedure is proposed to expand the diagnostic capabilities of the pressure tendency equation of a primitive equation NWP model by computing the pressure tendency in physical coordinates. The advantages of isolating the density advection as a diagnostic tool to understand pressure changes is shown. By simple thermodynamic arguments it is demonstrated that in areas of synoptic-scale cyclonic development, the vertically integrated density advection is more than sufficient to explain the depletion of mass over a growing depression. Consequently, the joint contribution of the net divergence and vertical motion opposes the pressure fall. This is illustrated for a case of rapid cyclogenesis in southern South America.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 119; 2936-295
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Publication Date: 2011-08-24
    Description: Previous methods to segment clouds from ocean in AVHRR imagery have shown varying degrees of success, with nighttime approaches being the most limited. An improved method of automatic image segmentation, the principal component transformation split-and-merge clustering (PCTSMC) algorithm, is presented and applied to cloud screening of both nighttime and daytime AVHRR data. The method combines spectral differencing, the principal component transformation, and split-and-merge clustering to sample objectively the natural classes in the data. This segmentation method is then augmented by supervised classification techniques to screen clouds from the imagery. Comparisons with other nighttime methods demonstrate its improved capability in this application. The sensitivity of the method to clustering parameters is presented; the results show that the method is insensitive to the split-and-merge thresholds.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Remote Sensing of Environment (ISSN 0034-4257); 38; 77-121
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Publication Date: 2011-08-24
    Description: A study of persistent, trapped magnetic field has been pursued with high-temperature superconducting (HTS) materials. The main effort is to study the feasibility of utilization of HTS to fabricate magnets for various devices. The trapped field, when not in saturation, is proportional to the applied field. Thus, it should be possible to replicate complicated field configurations with melt-textured YBa2Cu3O7 (MT-Y123) material, bypassing the need for HTS wires. Presently, materials have been developed from which magnets of 1.5 T, at 77 K, can be fabricated. Much higher field is available at lower operating temperature. Stability of a few percent per year is readily attainable. Results of studies on prototype motors and minimagnets are reported.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 70; 6501-650
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Publication Date: 2011-08-24
    Description: A laser diode current driver has been developed for free space laser communications. The driver provides 300 mA peak modulation current and exhibits an optical risetime of less than 400 ps. The current and optical pulses are well behaved and show minimal ringing. The driver is well suited for QPPM modulation at data rates up to 440 Mbit/s. Much previous work has championed current steering circuits; in contrast, the present driver is a single-ended on/off switch. This results in twice the power efficiency as a current steering driver. The driver electrical efficiency for QPPM data is 34 percent. The high speed switch is realized with a Ku-band GaAsFET transistor, with a suitable pre-drive circuit, on a hybrid microcircuit adjacent to the laser diode.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: In: Free-space laser communication technologies III; Proceedings of the Meeting, Los Angeles, CA, Jan. 21, 22, 1991 (A93-18923 05-74); p. 412-420.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Publication Date: 2011-08-19
    Description: Sandwich geometry superconductor/normal metal/superconductor structures have been fabricated on LaAlO3 and cubic zirconia with laser-ablated, c-axis-oriented YBa2Cu3O(7-delta) base electrodes, 100-600 A of Au, and Nb counter electrodes, all formed in situ without breaking vacuum. Junctions range in size from 5 to 50 micron on a side. Four probe I-V measurements at 4.2 K show RnA products as low as 6 x 10 to the -9th sq cm and critical current densities up to 5.2 kA/sq cm. AC Josephson steps were observed with the application of 10-GHz radiation. The temperature dependence of Jc and the observation of the AC Josephson effect suggest that true supercurrents are present and that they do indeed represent the characteristics of the YBa2Cu3O(7-delta)/Au/Nb structure. The best results were obtained when the devices were annealed at about 450 C in O2 for 30 min after Au deposition.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Magnetics (ISSN 0018-9464); 27; 1335-133
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Publication Date: 2011-08-19
    Description: A novel waveguide power transmission measurement technique was developed to extract the complex conductivity of superconducting thin films at microwave frequencies. The microwave conductivity was taken of two laser ablated YBa2Cu3O(7-delta) thin films on LaAlO3 with transition temperatures of approximately 86.3 and 82 K, respectively, in the temperature range 25 to 300 K. From the conductivity values, the penetration depth was found to be approximately 0.54 and 0.43 micron, and the surface resistance (R sub s) to be approximately 24 and 36 micro-Ohms at 36 GHz and 76 K for the two films under consideration. The R sub s values were compared with those obtained from the change in the Q-factor of a 36 GHz Te sub 011-mode (OFHC) copper cavity by replacing one of its end walls with the superconducting sample. This technique allows noninvasive characterization of high transition superconducting thin films at microwave frequencies.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Magnetics (ISSN 0018-9464); 27; 1284-128
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Publication Date: 2011-08-19
    Description: Allowing for a field-dependent critical current density, the authors calculate the magnetic field that can be supported by hollow cylinders of varying wall thickness. An adiabatically stable field of 1.0 T can be shielded by or trapped in a cylinder with a wall thickness of 0.4 cm if the critical current density varies linearly with magnetic field and has a value of 104 A/sq cm at a field of 1.0 T. Such a current density appears to be within reach of present state-of-the-art melt-processed YBa2Cu3O7 (123) materials.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Magnetics (ISSN 0018-9464); 27; 1047
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Publication Date: 2011-08-19
    Description: A resonant-tunneling diode has oscillated at X-band frequencies in a microwave circuit consisting of a slot antenna coupled to a semiconfocal open resonator. Coupling between the open resonator and the slot oscillator improves the noise-to-carrier ratio by about 36 dB relative to that of the slot oscillator alone in the 100-200 kHz range. A circuit operating near 10 GHz has been designed as a scale model for millimeter- and submillimeter-wave applications.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Electronics Letters (ISSN 0013-5194); 27; 647-649
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Publication Date: 2011-08-19
    Description: A guide-antiguide modulator of GaAs-AlGaAs using the electric-field-induced waveguide concept was demonstrated. The device was formed with a central waveguide electrode sandwiched between two antiguide electrodes on the surface of a p-i-n multiple quantum well (MQW). Switching between lateral guiding and antiguiding was accomplished by reverse biasing either the central electrode or the adjacent electrodes to increase the index beneath these respective regions. The on-off ratio was measured to be 20:1 with a propagation loss of the on-state of about 5 dB/mm.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Photonics Technology Letters (ISSN 1041-1135); 3; 141-143
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Publication Date: 2011-08-19
    Description: This study presents various approaches to parameterizing the broadband transmission functions for utilization in numerical climate models. One-parameter scaling is applied to approximate a nonhomogeneous path with an equivalent homogeneous path, and the diffuse transmittances are either interpolated from precomputed tables or fit by analytical functions. Two-parameter scaling is applied to parameterizing the carbon dioxide and ozone transmission functions in both the lower and middle atmosphere. Parameterizations are given for the nitrous oxide and methane diffuse transmission functions.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate (ISSN 0894-8755); 4; 424-437
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2011-08-19
    Description: A novel gate insulator consisting of silicon dioxide (SiO2) with a thin silicon (Si) interfacial layer has been investigated for high-power microwave indium phosphide (InP) metal-insulator-semiconductor field effect transistors (MISFETs). The role of the silicon interfacial layer on the chemical nature of the SiO2/Si/InP interface was studied by high-resolution X-ray photoelectron spectroscopy. The results indicated that the silicon interfacial layer reacted with the native oxide at the InP surface, thus producing silicon dioxide, while reducing the native oxide which has been shown to be responsible for the instabilities in InP MISFETs. While a 1.2-V hysteresis was present in the capacitance-voltage (C-V) curve of the MIS capacitors with silicon dioxide, less than 0.1 V hysteresis was observed in the C-V curve of the capacitors with the silicon interfacial layer incorporated in the insulator. InP MISFETs fabricated with the silicon dioxide in combination with the silicon interfacial layer exhibited excellent stability with drain current drift of less than 3 percent in 10,000 sec, as compared to 15-18 percent drift in 10,000 sec for devices without the silicon interfacial layer. High-power microwave InP MISFETs with Si/SiO2 gate insulators resulted in an output power density of 1.75 W/mm gate width at 9.7 GHz, with an associated power gain of 2.5 dB and 24 percent power added efficiency.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Electrochemical Society, Journal (ISSN 0013-4651); 138; 1788-179
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Publication Date: 2011-08-19
    Description: Results are presented on an automatic stereo analysis of cloud-top heights from nearly simultaneous satellite image pairs from the GOES and NOAA satellites, using a massively parallel processor computer. Comparisons of computer-derived height fields and manually analyzed fields show that the automatic analysis technique shows promise for performing routine stereo analysis in a real-time environment, providing a useful forecasting tool by augmenting observational data sets of severe thunderstorms and hurricanes. Simulations using synthetic stereo data show that it is possible to automatically resolve small-scale features such as 4000-m-diam clouds to about 1500 m in the vertical.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Applied Meteorology (ISSN 0894-8763); 30; 257-281
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Publication Date: 2011-08-19
    Description: A four-way crossover circuit using a cylindrical cavity with four rectangular input/output ports has been designed to feed a cross-slot antenna to achieve dual polarization. Because all the input and output circuits are waveguides, the network is especially useful for high power systems and millimeter wave applications. The crossover circuit exhibits a very low insertion loss and good isolation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Electronics Letters (ISSN 0013-5194); 27; 997
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Publication Date: 2011-08-19
    Description: An analysis is carried out to determine the discontinuity susceptance of a circular or rectangular aperture in the transverse plane of a circular waveguide. Closed-form solutions based on the scattered amplitude calculation and aperture coupling theory are derived. Example solutions for a small circular aperture and a resonant rectangular aperture are given. The calculated results agree very well with the experiments. The results have many applications in the design of circular waveguide components and circular waveguide-backed aperture antennas.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Microwave Theory and Techniques (ISSN 0018-9480); 39; 718-723
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Publication Date: 2011-08-19
    Description: The fabrication and performance of an Al(0.3)Ga(0.7)As/GaAs modulation-doped resistive-gate CCD are reported. The two-dimensional electron gas (2DEG) CCD, implemented as a 32-stage four-phase delay line, was tested at both low (1-13 MHz) and high (0.6-1.0 GHz) frequency. It exhibits a room-temperature charge-transfer efficiency (CTE) of better than 0.999 at clock frequencies from 10 MHz up to 1 GHz without a fat-zero signal and is limited by dark current below 10 MHz. The high-frequency test showed no CTE degradation up to 1-GHz operation. The CTE degraded at frequencies lower than approximately 5 MHz due to dark current. The charge-handling capability and minimum clock swing of the resistive-gate 2DEG CCD are calculated.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Electron Devices (ISSN 0018-9383); 38; 930-932
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Publication Date: 2011-08-19
    Description: Global precipitation estimates using satellite data are derived using difference fields of outgoing long-wave radiation (OLR). The difference fields consist of clear OLR minus cloudy OLR, which is a measure of long-wave cloud radiative forcing at the top of the earth-atmosphere system; and clear daytime OLR minus clear night-time OLR, which is a measure of the diurnal variation of surface heating. All geophysical parameters used to compute OLR are derived from an analysis of the HIRS2/MSU sounding data. The derived global precipitation estimates show good agreement with collocated raingage data over land.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Atmosphere - Ocean (ISSN 0705-5900); 29; 150-174
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Publication Date: 2011-08-19
    Description: The zonal and meridional wind contours in the 60-120 km region obtained from satellite radiance data were compared with radar-derived contours of winds obtained from the CIRA-1986 reference atmosphere. It was found that the agreement between the directly observed zonal winds and the zonal mean gradient winds from the reference atmosphere wind model was good, especially below 80 km. However, differences were found in both the Southern and the Northern Hemispheres.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 48; 411-428
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Publication Date: 2011-08-19
    Description: The observed effects of sharp changes in sea surface temperature (SST) on the air-sea fluxes, surface roughness, and the turbulence structure in the surface layer and the marine atmospheric boundary layer are discussed. In situ flux and turbulence observations were carried out from three aircraft and two ships within the FASINEX framework. Three other aircraft used remote sensors to measure waves, microwave backscatter, and lidar signatures of cloud tops. Descriptions of the techniques, intercomparison of aircraft and ship flux data, and use of different methods for analyzing the fluxes from the aircraft data are described. Changing synoptic weather on three successive days yielded cases of wind direction both approximately parallel and perpendicular to a surface temperature front. For the wind perpendicular to the front, wind over both cold-to-warm and warm-to-cold surface temperatures occurred. Model results consistent with the observations suggest that an internal boundary layer forms at the SST.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Geophysical Research (ISSN 0148-0227); 96; 8593-860
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Publication Date: 2011-08-19
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Geophysical Research (ISSN 0148-0227); 96; 9227-926
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Publication Date: 2011-08-19
    Description: A simple parameterization of ozone absorption in the 9.6-micron region which is suitable for two- and three-dimensional stratospheric and tropospheric models is presented. The band is divided into two parts, a brand center region and a band wing region, grouping together regions for which the temperature dependence of absorption is similar. Each of the two regions is modeled with a function having the form of the Goody random model, with pressure and temperature dependent band parameters chosen by empirically fitting line-by-line equivalent widths for pressures between 0.25 and 1000 mbar and ozone absorber amounts between 1.0 x 10 to the -7th and 1.0 cm atm. The model has been applied to calculations of atmospheric heating rates using an absorber amount weighted mean pressure and temperature along the inhomogeneous paths necessary for flux computations. In the stratosphere, maximum errors in the heating rates relative to line-by-line calculations are 0.1 K/d, or 5 percent of the peak cooling at the stratopause. In the troposphere the errors are at most 0.005 K/d.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Geophysical Research (ISSN 0148-0227); 96; 9065-907
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Publication Date: 2011-08-19
    Description: A radiative transfer method for treating nongray gaseous absorption and thermal emission in vertically inhomogeneous multiple scattering atmospheres is described. Probability density distributions of absorption coefficient strength are derived from line-by-line calculations to construct line-by-line and band model based k distributions. The monotonic ordering of absorption coefficient strengths in these k distributions implicitly preserves the monochromatic structure of the atmosphere at different pressure levels, thus simulating monochromatic spectral integration at a fraction of the line-by-line computing cost. The k distribution approach also permits accurate modeling of overlapping absorption by different atmospheric gases and accurate treatment of nongray absorption in multiple scattering media. It is shown that the correlated k distribution method is capable of achieving numerical accuracy to within 1 percent of cooling rates obtained with line-by-line calculations throughout the troposphere and most of the stratosphere.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Geophysical Research (ISSN 0148-0227); 96; 9027-906
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Publication Date: 2011-08-19
    Description: An efficient method for computing the transmission function in the 15-micron CO2 and the 9.6-micron O3 bands is presented. An inhomogeneous atmospheric path is treated as homogeneous by applying simple pressure and temperature scaling approximations. The transmission functions are then derived from small precomputed tables. Because the atmospheric cooling rate is primarily contributed from adjacent layers, the simple scaling approximations can be used to accurately compute transmission functions in both the middle and lower atmosphere. Applying the parameterization to vastly different atmospheric conditions, the difference with line-by-line calculations is small. In the region between 0.01 mbar and the earth's surface, the cooling rate difference is less than 0.3 C/d in the 15-micron CO2 band and less than 0.1 C/d in the 9.6-micron O3 band.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Geophysical Research (ISSN 0148-0227); 96; 9003-901
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Publication Date: 2011-08-19
    Description: Measured mutual coupling between two X-band electromagnetically coupled rectangular patch antennas is reported. Results are given for both the wideband and high gain regions as well as for E-plane and H-plane couplings.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Electronics Letters (ISSN 0013-5194); 27; 532
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Publication Date: 2011-08-19
    Description: The performance of a microstrip hammerhead filter that has been fabricated on an electrically thin layer of semiinsulating GaAs backed by a fused quartz substrate was measured and compared to results of a three-dimensional finite-difference time-domain (FD-TD) program used to calculate the response of the filter both with and without the GaAs layer. The program, presented by Sheen et al. (1990), discretizes the entire structure and then simulates the propagation of a Gaussian pulse through the filter. The microstrip filter is intended for applications involving ultrathin lifted-off or etched-back GaAs containing both active devices and passive microstrip circuitry backed by a much thicker mechanically rigid low-loss, low-dielectric-constant substrate. The low-pass characteristics of the hammerhead filter with the intermediate GaAs layer are compared with those of the same filter on quartz alone. Both the measured and computed data show a significant shift in cutoff frequency (about 10 percent at the 3 dB points) for a GaAs layer that is 0.007 wavelengths thick at 4 GHz.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Microwave and Guided Wave Letters (ISSN 1051-8207); 1; 78-80
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Boundary-layer moisture fluctuations are estimated by analyzing HAPEX and FIFE data collected on 52 aircraft flight legs. Moisture fluctuations were given considerable attention in the HAPEX flights, which were 120 km long, and flew 150 m over one area of homogeneous terrain. The repetitions permit statistical consideration of motion characteristics on horizontal scales. Two prototypical boundary layer regimes are discovered: the entrainment-drying boundary layer, and the moistening boundary layer. The latter demonstrates positive moisture skewness close to the surface related to high surface evaporation. The former is characterized by boundary-layer instability, weak surface evaporation, and drier air aloft, leading to unexpected negative moisture skewness. It is noted that 10 km moisture variations with horizontal gradients are often found in narrow zones of horizontal convergence, called mesoscale moisture fronts. A negative moisture to temperature correlation, due to surface energy budget inhomogeneity, is shown to incur large mesoscale variations of relative humidity.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Royal Meteorological Society, Quarterly Journal (ISSN 0035-9009); 117; 151-176
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Publication Date: 2011-08-19
    Description: The structure and propagation of tropical-cloud clusters are investigated during two contrasting periods over the tropical western Pacific in order to determine possible similarities or differences and to compare with previous studies. Three fundamental periodicities are found in tropical convection in the region: 1 day, 2-3 days, and 10-15 days. It is noted that the 10-15-day time scale is closely related to the intraseasonal oscillations propagating from the Indian Ocean to the western Pacific. Large convective complexes, supercloud clusters (SSC) are found to organize in this time scale. The SCC is made up from several cloud clusters generated at 2-3-day intervals. The diurnal variation is found to be most pronounced over the maritime continent, and the amplitude of the diurnal cycle is shown to be modulated by the 2-3-day and 10-15-day oscillations.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Geophysical Research (ISSN 0148-0227); 96; 3197-320
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Publication Date: 2011-08-19
    Description: Graphite intercalation compounds may provide an excellent material for the fabrication of electromagnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Magnetics (ISSN 0018-9464); 27; 289-293
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Publication Date: 2011-08-19
    Description: The observation of photon-assisted resonant tunneling in a multiple quantum well structure composed of doped quantum wells separated by variably space superlattice energy filters is reported. Electrons confined in the quantum wells are excited to the second quantized state by intersubband absorption of incident infrared radiation and are subsequently emitted through the filters under appropriate bias conditions. This is manifested by a distinct peak, with an associated negative differential photoconductance, in the photocurrent versus bias voltage characteristic at low temperatures.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 58; 1297
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Publication Date: 2011-08-19
    Description: Cloud-to-ground lightning is a significant forecast problem at the Kennedy Space Center (KSC) in Florida. In this study, cloud-to-ground lightning is related in time and space to surface convergence for 244 days during the convective seasons of 1985 and 1986 over a 790 sq-km network at KSC. The method uses surface convergence, particularly the average over the area, to identify the potential for new, local thunderstorm growth, and it can be used to specify the likely time and location of lightning during the life cycle of the convection. A threshold of 75 x 10 to the -6th/s change in divergence is the main criterion used to define a convergence event, and a set of flashes less than 30 min apart defines a lightning event. Time intervals are found from the study to be approximately 1 h from beginning convergence to first flash, and another hour to the end of lightning. The influences of low-level winds and midlevel moisture in determining the location and intensity of convection are discussed. This is the first known dynamically-based forecast method for lightning prediction. The technique, currently in use at KSC, has been shown to be a systematic, quantitative tool for predicting lightning onset in situations where conventional analysis tools such as radar and satellite are limited.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Weather and Forecasting (ISSN 0882-8156); 6; 49-64
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Publication Date: 2011-08-19
    Description: Using seven years (1981-1987) of ECMWF initialized analyses, the low-frequency (20-70 day) intraseasonal variability during Northern Hemisphere winter is examined, with emphasis on the zonal wind variability in the Pacific sector and on its relationship to the tropical convection and the middle-altitude wave propagation. Particular consideration is given to changes in the propagation characteristics associated with variations in the subtropical jet and the implications for low-frequency variability in middle latitudes. Also investigated is the relationship between the Pacific sector u-wind fluctuations and tropical convection anomalies.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 48; 629-650
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Publication Date: 2011-08-19
    Description: This study presents the first quantitative retrievals of vertical profiles of precipitation derived from multispectral passive microwave radiometry. Measurements of microwave brightness temperature (Tb) obtained by a NASA high-altitude research aircraft are related to profiles of rainfall rate through a multichannel piecewise-linear statistical regression procedure. Statistics for Tb are obtained from a set of cloud radiative models representing a wide variety of convective, stratiform, and anvil structures. The retrieval scheme itself determines which cloud model best fits the observed meteorological conditions. Retrieved rainfall rate profiles are converted to equivalent radar reflectivity for comparison with observed reflectivities from a ground-based research radar. Results for two case studies, a stratiform rain situation and an intense convective thunderstorm, show that the radiometrically derived profiles capture the major features of the observed vertical structure of hydrometer density.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Atmospheric and Oceanic Technology (ISSN 0739-0572); 8; 148-158
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Publication Date: 2011-08-19
    Description: An algorithm for the estimation of monthly rain totals for 5 deg cells over the ocean from histograms of SSM/I brightness temperatures has been developed. There are three novel features to this algorithm. First, it uses knowledge of the form of the rainfall intensity probability density function to augment the measurements. Second, a linear combination of the 19.35 and 22.235 GHz channels has been employed to reduce the impact of variability of water vapor. Third, an objective technique has been developed to estimate the rain layer thickness from the 19.35- and 22.235-GHz brightness temperature histograms. Comparison with climatologies and the GATE radar observations suggest that the estimates are reasonable in spite of not having a beam-filling correction. By-products of the retrievals indicate that the SSM/I instrument noise level and calibration stability are quite good.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Atmospheric and Oceanic Technology (ISSN 0739-0572); 8; 118-136
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Publication Date: 2011-08-19
    Description: The instrumented NASA ER-2 aircraft overflew severe convection with IR V features for the first time in the midwest United States during May 1984. Measurements taken by the ER-2 were: visible and IR imagery, high-frequency passive microwave (92, 183 GHz) imagery, nadir lidar backscattered return, and flight altitude information. The May 7 and May 13, 1984 cases are analyzed in detail and the various data sources are combined and compared with GOES imagery. The high resolution aircraft IR imagery shows that thermal couplets are considerably more pronounced than in GOES imagery. In one of the cases (May 7, 1984) the minimum cloud-top IR temperature was located upshear of the overshooting cloud top in the lidar height field. The IR temperatures in the downshear anvils were as much as 5 C warmer than the ambient air temperatures, implying that the upwelling IR radiance comes from about 0.5-1.0 km below the cloud top. The in situ ER-2 measurements of temperature and air velocity 3-4 km above the overshooting tops showed very intense temperature and vertical velocity, perturbations. These perturbations are suggestive of lee waves generated by the overshooting tops or a cold dome above the squall line possibly due to tropopause lifting by the storms.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 119; 436-456
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Publication Date: 2011-08-19
    Description: An overview is presented of the CERES experiment that is designed not only to monitor changes in the earth's radiant energy system and cloud systems but to provide these data with enough accuracy and simultaneity to examine the critical climate/cloud feedback mechanisms which may play a major role in determining future changes in the climate system. CERES will estimate not only the flow of radiation at the top of the atmosphere, but also more complete cloud properties that will permit determination of radiative fluxes within the atmosphere and at the surface. The CERES radiation budget data is also planned for utilization in a wide range of other Earth Observing System interdisciplinary science investigations, including studies of land, biological, ocean and atmospheric processes.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Publication Date: 2011-08-19
    Description: An experimental and numerical study is conducted of the operation of a major line in a vertical Bloch-line memory that employs a partial garnet-grooving architecture and contains (1) a bubble generator; (2) a bubble-propagation track; (3) a bubble-expander for detection; and (4) a bubble annihilator. The bubble expander is a modification of the propagation track; the meandering conductor and groove width were gradually increased to stretch the bubble into a stripe. The numerical model employed encompasses the garnet-grooving effect. Agreement is obtained between exparimental and simulation results.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 69; 5754-575
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Publication Date: 2011-08-19
    Description: Aircraft passive microwave observations at 18, 37, 92, and 183 GHz of light oceanic precipitation are studied in conjunction with visible and infrared observations and ground-based radar data. Microwave signatures for clear, cloudy, and precipitating conditions are defined, with results in general agreement with previous theoretical results. Emission signatures are evident at 18, 37, and 92 GHz with clouds and precipitation producing an increase in brightness temperature over that observed over the low-emissivity ocean background. Polarization differences at 18 and 37 GHz also decrease in precipitation areas to minima of 30 K at 18 GHz and 15 K at 37 GHz. The 92-GHz brightness temperature shows a double-valued relationship, with an increase in cloudy and very lightly raining areas and a subsequent decrease for higher rain rates and deeper clouds where the ice scattering process becomes important. The 183-GHz observations display a distinct sensitivity to small amounts of ice. Simple channel differences are shown to compare favorably to the rain field, including polarization differences at 18 and 37 GHz and frequency differences between 92 and 37 GHz and between 183 and 92 GHz.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Atmospheric and Oceanic Technology (ISSN 0739-0572); 8; 201-220
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Publication Date: 2011-08-19
    Description: Two cold-air outbreaks were studied during the Genesis of Atlantic Lows Experiment. A lidar system was operated to observe the boundary layer evolution and the development of clouds. On the first day (January 30, 1986) boundary layer rise was less than 50 percent of the value for the second day (March 2, 1986). On the first day only a thin broken cloud cover formed, while on the second day a thick solid cloud deck formed - although the average moisture content was 60 percent of that on the first day. A trajectory slab model was employed to simulate the evolution of the layer over the ocean near the east Atlantic shore. The model allows for vertical gradients in conservative variables under neutrally buoyant conditions. The primary effect of these assumptions, which are based on observed thermodynamic profiles, is to reduce cloudiness to be more in line with observations. Boundary-layer depth was reasonably well predicted as was sensible and latent heat flux.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 119; 1132-115
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Publication Date: 2011-08-19
    Description: An approach is described for using the linear sweep voltammetry (LSV) technique to study the kinetics of flooded porous electrodes by assuming a porous electrode as a collection of identical noninterconnected cylindrical pores that are filled with electrolyte. This assumption makes possible to study the behavior of this ideal electrode as that of a single pore. Alternatively, for an electrode of a given pore-size distribution, it is possible to predict the performance of different pore sizes and then combine the performance values.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Electrochemical Society, Journal (ISSN 0013-4651); 138; 258C-264
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-19
    Description: An outline is presented of the coilgun concept, excitation, switching, brush commutation, power supply, and performance. It is shown that a traveling-wave synchronous coilgun permits independent adjustment of the magnetic field and armature current for high velocity at low armature mass fraction. Magnetic field energy is transferred from the rear of the wave to the front without passing through the power supply. Elaborate switching is required.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Magnetics (ISSN 0018-9464); 27; 647-649
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Publication Date: 2011-08-19
    Description: Results are presented on an investigation of the effects of various assumptions (including assumptions of a constant flux field, a constant albedo field, and a variable albedo field) used for deriving the shortwave shape factor on the estimates, from radiometric measurements, of the albedo at the top of the atmosphere. The accuracies and the resolutions of the shape-factor-flux estimates obtained using these assumptions are determined by simulating the shape factor inversion technique with scanner data from the Earth Radiation Budget Experiment (ERBE). The resulting biases and variances are given for both the ERBE medium-field-of-view and wide-field-of-view radiometers.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 48; 390-402
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Publication Date: 2011-08-19
    Description: The spatial phase relationship between the atmospheric circulation and the bandpass fluctuations in cloudiness are investigated using satellite retrievals of high cloud areas reported by Stowe et al. (1988, 1989) NMC 500-mb geopotential heights in northern extratropics. Results of the analysis suggest that the high-cloud structures of baroclinic waves are less spatially coherent than the internal geopotential-height structures. It is shown that over the North Pacific, small-scale (latitudinal wavenumber 13-18) fluctuations in geopotential play a greater role in forcing high cloudiness than do medium-scale (latitudinal wavenumber 7-12) fluctuations in geopotential.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 119; 73-83
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-19
    Description: The consequence of frequency domain multiple access channelization in a satellite communications system is that the ground- and space-based components often are required to operate in a linear region to prevent the generation of distortion signals. Components of a time division multiple access (TDMA) satellite system, such as a traveling-wave tube (TWT), can operate in the highest output power state because the channelization technique is relatively insensitive to the distortions resulting from saturated operation. A 30 GHz TWT was tested to determine the suitability of such a device in a TDMA system. Testing was focused on the ability of the TWT's output signal to rise up to full power at the leading edge of TDMA bursts, simulated by a pulse train. A peak power meter was used to display and measure the pulsed signal waveform. Measurements on the TWT output pulse rise time indicate that the TWT lengthened the rise time by 10 to 20 ns. Imposing modulator turn on timing that precedes the data burst by the TWT rise time is a logical approach to coordination of the two subsystem specification.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Microwave Journal (ISSN 0192-6225); 34; 113
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Publication Date: 2011-08-19
    Description: Plasma-deposited germanium nitride was investigated for the first time as a possible gate insulator for InP compound semiconductor metal-insulator-semiconductor FET (MISFET) technology. The germanium nitride films were successfully deposited in a capacitively coupled parallel plate reactor at 13.56 MHz operation using GeH4/N2/NH3 and GeH4/N2 mixtures as reactant gases. The former process produced better quality films with enhanced uniformity, increased deposition rates, and increased resistivity. The breakdown field strength of the films was greater than 10 to the 6th V/cm. Auger electron spectroscopy did not indicate significant chemical composition differences between the two processes. For MISFETs with 2-micron channel lengths fabricated on InP, the device transconductance and threshold voltage for the GeH4/N2/NH3 process were 17 mS/mm and -3.6 V, respectively. The drain-source breakdown voltages were greater than 10 V.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 69; 3616-362
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Publication Date: 2011-08-19
    Description: A new version of the Goddard Laboratory for Atmospheres GCM is utilized to simulate the influence of an observed sea surface temperature anomaly on rainfall and atmospheric circulation. The model can reproduce many essential features of the observed tropical rainfall and circulation anomalies during January-February 1983. Particularly, the model simulates realistic patterns of tropical anomalies of sea level pressure, 200 mb geopotential heights, and horizontal winds at the 200 and 850 mb levels. The model-simulated tropical precipitation anomaly patterns appear realistic, although the precipitation is rather excessive and the atmosphere is too energetic.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate (ISSN 0894-8755); 4; 107-115
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Publication Date: 2011-08-19
    Description: In an optically fed phased array antenna system, the microwave carrier signal is transmitted via a modulated lightwave to each active T/R (transmit/receive) module, where it must be converted back to the microwave domain. Currently, efficient optical-to-microwave conversion is extremely difficult, as the detected microwave signal is weak and noisy. A novel circuit, containing a high-gain/low-noise microwave injection-locked oscillator, has been developed to improve the interface between the optical and microwave components. The circuit utilizes two FETs and a dielectric resonator, which serves as a frequency-dependent feedback element. The circuit, designed to operate at about 8 GHz, provides significant amplitude and phase noise suppression. In addition, the circuit realization is compatible with MMIC technology.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Microwave Theory and Techniques (ISSN 0018-9480); 39; 201-208
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Publication Date: 2011-08-19
    Description: An aircraft experiment has been conducted with a dual-frequency (X/Ka-bands) radar to test various rainfall retrieval methods from space. The authors test a method to derive raindrop size distribution (DSD) parameters from the combination of a radar reflectivity profile and a path-integrated attenuation derived from surface return, which may be available from most spaceborne radars. The estimated DSD parameters are reasonable in that the values generally fall within the range of commonly measured ones and that shifts in DSD parameters appear to be correlated with changes in storm type. The validity of the estimation result is also demonstrated by a consistency check using the Ka-band reflectivity profile which is independent of the DSD estimation process. Although errors may occur in the cases of nonuniform beam filling, these test results indicate the feasibility of the dual-parameter radar measurement from space in achieving a better accuracy in quantitative rainfall remote measurements.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); 29; 690-703
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Publication Date: 2011-08-19
    Description: A theoretical comparison of various low and high order multipliers for 200 GHz and 1 THz has been carried out. Novel diodes including single barrier varactors, barrier-intrinsic-n(+)diodes and high electron mobility varactors are shown to have excellent theoretical performance, comparable or better than the conventional Schottky varactors for single and double diode frequency multipliers at millimeter and submillimeter wavelengths, whereas quantum well diodes, since they suffer from high resistive losses, are shown to be less attractive. In comparison to the conventional Schottky varactor, these new diodes have some potential advantages in their characteristics such as a stronger nonlinearity or a special symmetry. For future optimization some general comments on these advantages as well as other factors affecting multiplication are given.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: International Journal of Infrared and Millimeter Waves (ISSN 0195-9271); 12; 1111-113
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Publication Date: 2011-08-19
    Description: The meteorological measurement system (MMS) on the U-2 aircraft measured pressure, temperature, and the horizontal wind during a cyclogenesis event over western United States on April 20, 1984. The mean horizontal wind in the stratosphere decreases monotonically with altitude. Superimposed on the mean stratospheric wind is a perturbation wind vector, which is an elliptically polarized wave with an amplitude of 4 to 10 m/s and a vertical wavelength of 2 to 3 km. The perturbation wind vector rotates anticyclonically (clockwise) with altitude and produces alternating advection in the plane of the aircraft flight path. This differential advection folds surfaces of constant tracer mixing ratio and contributes to the observed tracer laminar structures and inferred cross-jet transport.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Geophysical Research (ISSN 0148-0227); 96; 17
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Publication Date: 2011-08-19
    Description: A study of differences between the morning and evening monthly rainfall for 5 x 5 deg cells over the oceans from the SSM/I data has been conducted. The monthly rainfalls are estimated from the technique given by Wilheit et al. The difference between the morning and evening monthly rainfall arises due to the various random errors involved in the retrieval process, the sampling error in the observations, and the diurnal component of oceanic rainfall. The diurnal component is weak but clearly visible when averaged over large areas and for long time periods. The analysis shows that morning rainfall is consistently greater than evening rainfall. The Northern Hemisphere seem to have a larger diurnal variation than does the Southern Hemisphere. The maximum ratio between the morning and evening monthly rainfall is 1.7 while 1.2 is the more typical value.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 119; 2168-217
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Publication Date: 2011-08-19
    Description: Infrared radiance measurements were acquired from a narrow-field nadir-viewing radiometer based on the NASA ER-2 aircraft during a coincident Landsat 5 overpass on October 28, 1986 as part of the FIRE Cirrus IFO in the vicinity of Lake Michigan. The spectral bandpasses are 9.90-10.87 microns for the ER-2-based radiometer and 10.40-12.50 microns for the Landsat thematic mapper band. After adjusting for spatial and temporal differences, a comparative study using data from these two instruments is undertaken in order to retrieve cirrus cloud ice-crystal sizes and optical depths. Retrieval is achieved by analysis of measurement correlations between the two spectral bands and comparison to multistream radiative transfer model calculations. The results indicate that the equivalent sphere radii of the cirrus ice crystals were typically less than 30 microns. Such particles were too small to be measured by the available in situ instrumentation. Cloud optical depths at a reference wavelength of 11.4 microns ranged from 0.3 to 2.0 for this case study. Supplemental results in support of this study are described using radiation measurements from the King Air aircraft, which was also in near coincidence with the Landsat overpass.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 119; 1673-169
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Publication Date: 2011-08-19
    Description: The paper reports on a detailed experimental investigation of lateral tunneling between electrodes of a two-dimensional electron gas separated by the voltage-controlled barrier of a nanometer Schottky gate. The experimental data are modeled using the WKB method to calculate the tunneling probability of electrons through a barrier whose shape is determined from a solution of the two-dimensional Poisson equation. This model is in excellent agreement with the experimental data over a two order of magnitude range of current.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 59; 213-215
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Publication Date: 2011-08-19
    Description: The performance of several ice parameterizations has been evaluated through a numerical cloud model. Ice effects using different schemes are contrasted with each other and with an ice-free control by incorporating them into the cloud model and by applying them to simulations of tropical squall systems. The latter are simulated in 2D so that a large domain can be used to incorporate a complete anvil. Nonsquall-type convective lines are simulated in 3D owing to their smaller horizontal scale. It is concluded that inclusion of ice microphysics in the cloud model enhanced the agreement of the simulated convection with some features of observed convection, including the proportion of surface rainfall in the anvil region and the intensity and structure of the radar brightband near the melting level in the anvil. In the experiments with bulk microphysics, three ice categories produced much better results than two ice categories, which in turn was better than no ice. For the tropical squall-type and nonsquall-type systems the optimal mix was ice, snow, and graupel.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Applied Meteorology (ISSN 0894-8763); 30; 985-1004
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Publication Date: 2011-08-19
    Description: An analysis of the expected space radiation effects on the single event upset (SEU) properties of CMOS/bulk memories onboard the Combined Release and Radiation Effects Satellite (CRRES) is presented. Dose-imprint data from ground test irradiations of identical devices are applied to the predictions of cosmic-ray-induced space upset rates in the memories onboard the spacecraft. The calculations take into account the effect of total dose on the SEU sensitivity of the devices as the dose accumulates in orbit. Estimates of error rates, which involved an arbitrary selection of a single pair of threshold linear energy transfer (LET) and asymptotic cross-section values, were compared to the results of an integration over the cross-section curves versus LET. The integration gave lower upset rates than the use of the selected values of the SEU parameters. Since the integration approach is more accurate and eliminates the need for an arbitrary definition of threshold LET and asymptotic cross section, it is recommended for all error rate predictions where experimental sigma-versus-LET curves are available.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); 38; 913-922
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Publication Date: 2011-08-19
    Description: The dependence of stability on basic state wave phase speed is examined in a nondivergent barotropic model on a sphere for planetary scale waves with phase speeds typical of waves observed in the atmosphere. Triad interactions are examined analytically and compared to numerical results from a full spectral model. A number of triads may result in growth of the perturbation components for each basic state wave; for each triad there is a basic state wave phase speed where it is resonant, identified as the point where the critical amplitude for instability to that perturbation becomes zero. Critical amplitudes for instability obtained using the full spectral model generally agree well with triad results. Since the basic state wave phase speed determines which triad will grow, spatial structure and critical amplitudes for instability for the growing disturbances depend strongly on basic state wave phase speed. The results of this idealized study suggest that phase speed may be an important factor in determining the stability of planetary scale waves in the atmosphere.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Royal Meteorological Society, Quarterly Journal (ISSN 0035-9009); 117; 319-331
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Publication Date: 2011-08-19
    Description: The longest-wavelength quantum well infrared photodetector (QWIP) ever measured is demonstrated. This QWIP has a cutoff wavelength of 14.9 microns. The results show that even longer wavelength detectors should be possible.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Electronics Letters (ISSN 0013-5194); 27; 1512
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Publication Date: 2011-08-19
    Description: Satellite observations and numerical model results have been used to study the relationship between upper-tropospheric forcing and the oscillation of convection of tropical cyclones Florence (1988) and Irene (1981) during their mature stage over open warm oceans (SST greater than or equal to 26 C). It is suggested that the initiation and maintenance of intense convective outbreaks in tropical cyclones are related to the channeling and strengthening of their outflow by upper-tropospheric troughs. It is possible to enhance the convection in response to the outflow jet-induced import of eddy relative angular momentum and ascending motion associated with the thermally direct circulation. Both Florence and Irene are found to intensify after the onset of these convective episodes. It is also suggested that the cessation in the convection of the two tropical cyclones occurs when the upper-tropospheric troughs move near or over the tropical cyclones, resulting in the weakening of their outflow and the entrainment of dry upper-tropospheric air into their inner core.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Applied Meteorology (ISSN 0894-8763); 30; 1163-118
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Publication Date: 2011-08-19
    Description: A simple scheme is developed for calculating the cloud amount, optical thickness, and height from satellite-measured radiances and is applied to the International Satellite Cloud Climatology Project B3 radiance data to compute the surface radiative fluxes over the tropical and subtropical western Pacific regions for July 1983, using a radiative transfer model. Results are presented on the sensitivity of surface radiation to the cloud scheme. In addition, the validity of an empirical relationship between the solar fluxes at the surface and at the top of the atmosphere is examined.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 48; 1549-155
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Publication Date: 2011-08-19
    Description: The roles of the Critical Cloud Work Function (CCWF) data set and the upper and lower bounds on entrainment by cumulus plumes in the Arakawa-Schubert cumulus parameterization (ASCP) in the GLA GCM (Geller et al., 1988) were investigated in two sets of experiments. It was found that the horizontal and vertical distribution of cumulus heating can be altered in ASCP by adjusting these parameters. These changes can have a strong influence on the vertical structure of condensation heating, water vapor distribution, temperature, and rainfall. The CCWF is an important limiting parameter that controls the onset of different cloud types; increasing the threshold values of CCWF for all clouds tends to concentrate the rainfall into a narrower ITCZ and affects the rainfall during the initial adjustment period.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 48; 1573-158
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Publication Date: 2011-08-19
    Description: Depletion-mode InGaAs microwave power MISFETs with 1-micron gate lengths and up to 1-mm gate widths have been fabricated using an ion-implantation process. The devices employed a plasma-deposited silicon/silicon dioxide gate insulator. The dc I-V characteristics and RF power performance at 9.7 GHz are presented. The output power, power-added efficiency, and power gain as a function of input power are reported. An output power of 1.07 W with a corresponding power gain and power-added efficiency of 4.3 dB and 38 percent, respectively, was obtained. The large-gate-width devices provided over twice the previously reported output power for InGaAs MISFETs at X-band. In addition, output power stability within 1.2 percent over 24 h of continuous operation was achieved. In addition, a drain current drift of 4 percent over 10,000 sec was obtained.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Microwave Theory and Techniques (ISSN 0018-9480); 39; 1069-107
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Publication Date: 2011-08-19
    Description: The controllable, reproducible fabrication of nonhysteretic Josephson devices with excess-current weak-link characteristics at temperatures up to 80 K have been demonstrated. The devices are patterned from in situ deposited a-axis oriented YBa2Cu3O(7-y) - PrBa2Cu3O(7-y) - YBa2Cu3O(7-y) trilayers grown on SrTiO3(001) substrates. Control of the critical current density and resistance is achieved by varying the thickness of the PrBa2Cu3O(7-z) barrier layer. Critical current densities in excess of 10,000 A/sq cm have been reproducibly measured; good uniformity across the wafer is obtained with device parameters scaling with device area. Strong constant-voltage current steps are observed under 11.2 GHz microwave radiation at temperatures up to and above 80 K.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 59; 742-744
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Large-scale snow cover anomalies are thought to cause significant changes in the diabatic heating of the earth's surface in such a way as to produce substantial local cooling in the surface temperatures. This theory was tested using the GISS 3D GCM (General Circulation Model). The results of the GCM experiment showed that snow cover caused only a short term local decrease in the surface temperature. In the surface energy budget, reduction in absorbed shortwave radiation and the increased latent heat sink of melting snow contributed to lower temperatures. However, all the remaining heating terms contribute to increasing the net heating over a snow covered surface. The results emphasize the negative feedback which limits the impact of snow cover anomalies over longer time scales.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate (ISSN 0894-8755); 4; 689-706
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Publication Date: 2011-08-19
    Description: Turbulence and heat fluxes in the marine atmospheric boundary layer (MABL) for three aircraft stacks near the western Gulf Stream front, observed during the Genesis of Atlantic Lows Experiment (GALE) January 28, 1986 cold-air outbreak, has been studied using mixed-layer scaling. The GOES image and stability parameter indicates that these three stacks were in the roll vortex regime. The turbulence structure in the MABL is studied for this case, as well as the significance of roll vortices to heat fluxes. The roll circulations are shown to contribute significantly to the sensible (temperature) and latent heat (moisture) fluxes with importance increasing upward. The results suggest that the entrainment at the MABL top might affect the the budgets of temperature and humidity fluxes in the lower MABL, but not in the unstable surface layer.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Boundary-Layer Meteorology (ISSN 0006-8314); 55; 3, Ma
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-19
    Description: The radiative effects of clouds on the climate system are reviewed on the basis of data published over the last 15-20 years and some relevant unpublished model studies. Emphasis is placed on the impact of clouds on the incoming and outgoing radiation at the top of the atmosphere and the two-way interaction of clouds with other variables of the climate system, i.e., the cloud/climate feedback problem, as revealed by climate model simulations. Investigations aimed at determining the overall effects of clouds on the climate system (climate forcing) show that clouds have a net cooling effect. Two estimates of the global annual average effect of clouds on the net flux at the top of the atmosphere, based on recent satellite observations, show wide discrepancies. The sign of cloud feedback is found to be positive when the spatial distribution of clouds is allowed to vary in response to climate change. It is concluded that clouds may have a strong influence on climate change, but the magnitude of this influence is unknown.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: American Meteorological Society, Bulletin (ISSN 0003-0007); 72; 795-813
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-19
    Description: A recent work of Spencer and Christy (1990) on precise monitoring of global temperature trends from satellites is critically examined. It is tentatively concluded in the present comment that remote sensing using satellite microwave radiometers can in fact provide a means for the monitoring of troposphere-averaged air temperature. However, for this to be successful more than one decade of data will be required to overcome the apparent inherent variability of global average air temperature. It is argued that the data set reported by Spencer and Christy should be subjected to careful review before it is interpreted as evidence of the presence or absence of global warming. In a reply, Christy provides specific responses to the commenters' objections.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Science (ISSN 0036-8075); 251; 316; Rep
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Publication Date: 2011-08-19
    Description: Advances in high-frequency resonant-tunneling-diode (RTD) oscillators are described. Oscillations up to a frequency of 420 GHz have been achieved in the GaAs/AlAs system. Recent results obtained with In0.53Ga0.47As/AlAs and InAs/AlSb RTDs show a greatly increased power density and indicate the potential for fundamental oscillations up to about 1 THz. These results are consistent with a lumped-element equivalent circuit model of the RTD. The model shows that the maximum oscillation frequency of the GaAs/AlAs RTDs is limited primarily by series resistance, and that the power density is limited by low peak-to-valley current ratio.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Microwave and Optical Technology Letters (ISSN 0895-2477); 4; 19-23
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...