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  • 1
    Publication Date: 2004-12-03
    Description: Quenched Carbonaceous Composites (QCC's) are products from the ejecta of a hydrocarbon plasma. Two types of QCC, dark QCC and thermally-altered (heated) filmy QCC, have been shown to have a 220 nm absorption feature similar to that seen in the interstellar extinction curve. We present here Raman spectra of the QCCs and compare them with various carbonaceous materials to better understand the structure QCC. We find that structure of QCC is different from that of graphite and more similar to carbonaceous material found in some interplanetary dust particles and chondritic meteorites.
    Keywords: Astrophysics
    Type: From Stardust to Planetesimals: Contributed Papers; 227-230; NASA-CP-3343
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  • 2
    Publication Date: 2013-08-31
    Description: Characteristics of the electron-doped-type Nd(2-x)Ce(x)CuO4 systems and substituted Bi2(Sr,Ln)3Cu2Oy system were systematically studied using the high quality thin-film samples. The Nd(2-x)Ce(x)CuO4 thin films with various Ce concentrations, x, were prepared by RF magnetron sputtering on SrTiO3 heated at around 500 C. After subsequent annealing at 1100 C in air, the films showed the c-axis orientation normal to the substrates. By means of the reducing treatment (annealing in a vacuum), superconductivity was induced for the films with 0.14 is less than or equal to x is less than or equal to 0.18. The superconductivity and transport properties of the films were strongly affected by the reducing treatment. The x = 0.15 film exhibited a sharp superconducting transition with zero resistivity at 22 K, in consistent with the diamagnetic properties. The resistivity of the films was fairly low with metallic characteristics, and the sight of the Hall coefficient was negative in the normal state. On the other hand, the normal-state optical measurements showed that the undoped Nd2CuO4 is a semiconductor with a charge transfer gap of 1.3 eV, and that, when Ce ions were doped, a plasma reflection due to the free-carriers came to be seen with the plasma frequency of 1.07 eV for 0.14 is less than or equal to x is less than or equal to 0.18. Moreover, x ray photoemission study revealed that the Cu valence of the film decreased for 2(+) for x = 0 to 1(+) for x = 0.15. These physical properties are in contrast with those of hole-doped-type cuprate superconductors. Bi2(Sr,Ln)3Cu2Oy thin films were also prepared on MgO substrates heated at 600 to 700 C by similar methods. It was found that the growth conditions for Bi-systems with two CuO2 planes were different for each composition and species of lanthanoid in the films. Moreover, preparation of Bi-system with three CuO2 planes was very difficult when lanthanoid atoms were doped in the system. Their electric transport properties and x ray photoemission spectroscopy were investigated. Carrier concentration and Cu valence were discussed with regard to the superconductivity.
    Keywords: SOLID-STATE PHYSICS
    Type: NASA, Goddard Space Flight Center, AMSAHTS 1990: Advances in Materials Science and Applications of High Temperature Superconductors; p 35
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  • 3
    Publication Date: 2013-08-31
    Description: Characteristics of the electron-doped-type Nd(sub 2-x)Ce(sub x)CuO4 system and substituted Bi-system were studied using the high quality thin film samples grown by rf magnetron sputtering and/or subsequent heat treatment. The Nd(sub 2-x)Ce(sub x)CuO4 samples with excellent superconducting properties were obtained in thin films and their optical and X-ray photoelectron spectroscopy (XPS) studies were performed with regard to the Ce content and reducing treatment. Substituted BiSr-Ln-Cu-O thin films were prepared and growth conditions for Bi-system with 2-2-1-2 and 2-2-2-2 phases were found. Moreover, a new 2-2-1-2 phase in the simple Bi-Sr-Cu-O system was fabricated by thin film processing and 80 K superconductivity was obtained.
    Keywords: SOLID-STATE PHYSICS
    Type: NASA. Goddard Space Flight Center, AMSAHTS 1990: Advances in Materials Science and Applications of High Temperature Superconductors; p 281-290
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  • 4
    Publication Date: 2013-08-31
    Description: Water revitalization for a space station can consist of membrane filtration processes and a distillation process. Water recycling equipment using membrane filtration processes was manufactured for ground testing. It was assembled using commercially available components. Two systems for the distillation are studied: one is absorption type thermopervaporation cell and the other is a vapor compression distiller. Absorption type thermopervaporation, able to easily produce condensed water under zero gravity, was investigated experimentally and through simulated calculation. The vapor compression distiller was studied experimentally and it offers significant energy savings for evaporation of water.
    Keywords: MAN/SYSTEM TECHNOLOGY AND LIFE SUPPORT
    Type: NASA, Ames Research Center, Controlled Ecological Life Support System: Regenerative Life Support Systems in Space; p 71-74
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  • 5
    Publication Date: 2011-08-12
    Description: Density and heat of fusion of folded chain polyethylene crystals
    Keywords: CHEMISTRY
    Type: ARMY NATICK LABS. POLYMER STRUCT. AND MECH. PROPERTIES APR. 1967; P 215-245
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  • 6
    Publication Date: 2016-06-07
    Description: An area of about 9 by 10 arc minutes in the M17 molecular cloud has been mapped in the J=3-2 transition of CO. The strongest CO emission is observed to come from the two bars to the north and southwest, which lie just outside the area of ionized gas seen in the radio continuum studies. We are viewing the boundary between the ionized and molecular gas almost edge on. The most intense CO emission is from the area around the dense molecular cloud core M17SW in the southwest bar. To the east of M17SW there are signs of recent or continuing star formation including H2O masers and an ultra-compact HII region. The CO J=3-2 spectra observed are complex with considerable variation in line shapes occuring over distances of less than one arc minute. We interpret the velocity structure of this region as arising from an ensemble of molecular cloud fragments in addition to extended emission. We have identified several cloud components at different velocities within both the northern and southwest bars of CO emission. A simple kinematic model of the cloud components in the southwest bar in which they are considered to be clumps of post-shock gas lying close to the edge of the expanding HII region, with the shock being driven by Kleinmann's star, gives a velocity of approx. 10.8 km s(-1) for the expansion velocity of the HII region, which is currently at a distance of approx. 2.4 pc from Kleinmann's star. The resulting shock is thought to be preceding the ionisation front and appears to have led to the fragmentation of the original cloud.
    Keywords: ASTROPHYSICS
    Type: NASA. Ames Research Center Summer School on Interstellar Processes: Abstracts of Contributed Papers; p 33-34
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  • 7
    Publication Date: 2019-06-27
    Description: We report an orbital characterization of GJ1108Aab that is a low-mass binary system in the pre-main-sequence phase. Via the combination of astrometry using adaptive optics and radial velocity measurements, an eccentric orbital solution of e = 0.63 is obtained, which might be induced by the KozaiLidov mechanism with a widely separated GJ1108B system. Combined with several observed properties, we conrm that the system is indeed young. Columba is the most probable moving group, to which the GJ1108A system belongs, although its membership to the group has not been established. If the age of Columba is assumed for GJ1108A, the dynamical masses of both GJ1108Aa and GJ1108Ab (M(sub dynamical,GJ1108Aa) = 0.72 0.04 Solar Mass and M(sub dynamical,GJ1108Ab) = 0.30 0.03 Solar Mass) are more massive than what an evolutionary model predicts based on the age and luminosities. We consider that the discrepancy in mass comparison can be attributed to an age uncertainty; the system is likely older than stars in Columba, and effects that are not implemented in classical models such as accretion history and magnetic activity are not preferred to explain the mass discrepancy. We also discuss the performance of the evolutionary model by compiling similar low-mass objects in the evolutionary state based on the literature. Consequently, it is suggested that the current model on average reproduces the mass of resolved low-mass binaries without any signicant offsets.
    Keywords: Astrophysics
    Type: GSFC-E-DAA-TN64800 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 865; 2; 152
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  • 8
    Publication Date: 2018-06-08
    Description: Experiments and analyses have confirmed the feasibility of an innovative, new class of very simple, reliable, low mass, low packaging volume, and low-cost self-deployable structures for space and commercial applications.
    Type: International Society for Optical Engineering (SPIE) 03 Symposium on Smart Structures and Materials; San Diego, CA; United States
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  • 9
    Publication Date: 2019-06-27
    Description: Density determination by flotation method for solution grown crystals of polyethylene, noting specific volume-heat of fusion relationships
    Keywords: MATERIALS, NONMETALLIC
    Type: ; ADEMIE DES SCIENCES
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  • 10
    Publication Date: 2019-07-13
    Description: We successfully produced Resistive-Electrode Gas Electron Multiplier (RE-GEM) which has resistive electrodes instead of the metal ones which are employed for the standard GEM foils. RE-GEM has a resistive electrode of 25 micron-thick and an insulator layer of 100 micron-thick. The hole structure of RE-GEM is a single conical with the wider and narrower hole diameters of 80 micron and 60 micron, respectively. A hole pitch of RE-GEM is 140 micron. We obtained the maximum gain of about 600 and the typical energy resolution of about 20% (FWHM) at an applied voltage between the resistive electrodes of 620 V, using a collimated 8 keV X-rays from a generator in a gas mixture of 70% Ar and 30% CO2 by volume at the atmospheric pressure. We measured the effective gain as a function of the electric field of the drift region and obtained the maximum gain at an drift field of 0.5 kV/cm.
    Keywords: Electronics and Electrical Engineering; Instrumentation and Photography
    Type: GSFC-E-DAA-TN9680 , International Conference on Micro Pattern Gaseous Detectors; Aug 29, 2011 - Sep 11, 2011; Kobe; Japan|Journal of Instrumentation (ISSN 1748-0221); 7; 6; C06006
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