ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Ab initio studies on the electronic structures of strained-layer superlattices (InAs)n(InP)n(001), (n=1–5) (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 2556-2563 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report ab initio studies on the electronic structures of strained-layer superlattices (SLSs) (InAs)n(InP)n(001), (n=1–5) under three different strain conditions via a linearized muffin-tin-orbital method with two treatments for d states. The effects of In 4d orbitals on the band structure and the valence band offset (VBO) are investigated. The hydrostatic pressure behavior and the Γ–X mixture in these SLS systems are also discussed. It is found that the band gap of the InP/InAs system is insensitive to its layer thickness. The VBO values at the SLS's under the three strain conditions are determined by a frozen potential approach. Our results demonstrate that for the InP/InAs system the bulklike property is almost recovered in the molecular layer next to the interface. This behavior may be due to the common cation on both sides of the interface. This makes the frozen-potential approach converge very fast with the layer thickness. Our results of band structure for the (1+1) SLS under a free-standing mode are consistent with those given by a more elaborate full-potential linearized augmented-plane-wave (FLAPW) calculation. The present results of VBO are about 0.07–0.09 eV larger than the data from an x-ray photoelectron spectroscopy measurement and the FLAPW method, while in good agreement with the results given by the model solid theory. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358717
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Velocity autocorrelations of decaying isotropic homogeneous turbulence (1995)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 7 (1995), S. 2455-2464 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Velocity autocorrelations and the mean-square displacements of fluid particles are obtained for decaying, isotropic homogeneous turbulence by numerical simulation of the flow field, using 1283 and 2563 grids, and tracking several tens of thousands of fluid particles, using a third-order interpolation scheme. A self-preserving Lagrangian velocity autocorrelation coefficient is found in terms of a dimensionless time variable s, defined by ds=dt/Ts(t), under the observation of a power-law energy decay and the assumption that Ts(t) is proportional to the Lagrangian integral timescale TL. This timescale is in turn assumed to be proportional to the length scale of the energy-containing eddies Le∼K3/2/ε divided by the turbulent velocity u′, where K=3/2u′2 is turbulent energy and ε is the energy dissipation rate. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.868780
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Correlations of vorticity and material line elements with strain in decaying turbulence (1996)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 8 (1996), S. 2203-2214 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Correlations of the vorticity and the passive material line element with strains in decaying turbulence are investigated. The mean principal rates of the strain and the growth rates of the vorticity and the material line element due to the nonlinear stretching are all found to be proportional to the square-root-mean enstrophy. The ratios of the principal rates are 4:1:−5. It is shown how these ratios help determining the values of free parameters in the phenomenological models of turbulence such as the Burgers vortex model proposed by Ashurst (private communication) and the Lundgren–Townsend vortex model by Pullin and Saffman [Phys. Fluids A 5, 126 (1993); 6, 3010 (1994)]. The mean growth rate of material line elements is slightly larger than the intermediate principal rate, but much less than the most positive one. Numerical results show that the material line element has nearly the same preferences in aligning with the principal directions of the strain corresponding to the mostly positive and the intermediate principal rates. The growth rate is approximately linearly correlated with the strain magnitude but almost uncorrelated with the vorticity magnitude. Conditional statistics and a simple model flow have been used to explain the above observations. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.868993
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Average bond energy model for determining valence-band offsets at strained heterointerfaces Si,Ge,InP,GaAs/GexSi1−x (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 872-879 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A full description is presented of the "average bond energy model,'' which was developed for the determination of valence-band offset at heterojunctions. It is shown that this model is related conceptually to Harrison's tight binding "pinned'' model, while it overcomes all of the shortcomings of the latter. Its final form turns out to be a generalization of Cardona's dielectric-midgap-energy model. The average bond energy model is also shown related to Tersoff's charge-neutrality-point model. In this article, this model is used in conjunction with a cluster expansion method to determine systematically the valence-band offsets at four strained alloy type heterointerfaces, Si,Ge,InP,GaAs/GexSi1−x as functions of the alloy composition x. Good agreement is found between our results and available experimental data. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362896
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Development and in Vitro-in Vivo Evaluation of a Multiparticulate Sustained Release Formulation of Diltiazem (1995)
    Springer
    Pharmaceutical research 12 (1995), S. 1338-1342 
    Details
    ISSN: 1573-904X
    Keywords: Sustained release ; diltiazem ; in vitro ; in vivo ; ethyl-cellulose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To develop and evaluate the in vitro/in vivo performance of diltiazem sustained release pellets that were prepared by the Wurster column process. Methods. Pellets containing diltiazem were prepared by spraying a slurry of micronized diltiazem hydrochloride, pharmaceutical glaze and alcohol onto an appropriate mesh fraction of nonpareil seeds using the Wurster column. A two-step drug layering process was used to increase drug loading from 60% to 75%. The oven-dried diltiazem basic pellets were coated with eth-ylcellulose/dibutyl sebacate coating solution to yield diltiazem sustained release pellets. An open, randomized Latin square, three-way crossover clinical study was used to evaluate the in vivo performance of the coated product. Results. Altering the mesh fraction of the starting nonpareil seeds for this layering process was found to affect the release characteristics of drug from the pellets. An oven-drying step was required to stabilize the diltiazem basic pellets. The thicker the drug loading layer the longer the oven drying is needed to stabilize the pellets. The diltiazem sustained release pellets produced by these methods displayed sustained release dissolution profiles both in vitro and in vivo. Diltiazem basic pellets coated with a 0.6% ethylcellulose/dibutyl sebacate coating showed a different rate of absorption (lower C max and higherT max) and the same extent of absorption as compared to Cardizem® tablets. Conclusions. Clinical data confirmed that this formulation approach is an effective means to produce a diltiazem sustained release product.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016229808716
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    New HLA–DPB1 alleles generated by interallelic gene conversion detected by analysis of sperm (1995)
    [s.l.] : Nature Publishing Group
    Nature genetics 10 (1995), S. 407-414 
    Details
    ISSN: 1546-1718
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] The rate at which allelic diversity at the HLA loci evolves has been the subject of considerable controversy. The patchwork pattern of sequence polymorphism within the second exon of the HLA class II loci, particularly in the DPB1 locus, may have been generated by segmental exchange (gene ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/ng0895-407
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Magnesium oxide-supported polytitazane cobalt(III) complex for catalytic epoxidation of α-pinene with molecular oxygen (1996)
    Springer
    Polymer bulletin 36 (1996), S. 1-5 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Magnesium oxide-supported polytitazane cobalt complex has been prepared and found to be a very effective catalyst for the epoxidation of α-pinene in the presence of an aldehyde as a reductant. XPS data show that the high valent cobalt(III) was stabilized by the mutidentate nitrogen ligand of polytitazane. The α-pinene oxide can be obtained in 96.0% yield with 96.6% selectivity at 25°C under an atmospheric pressure of molecular oxygen. Isobutyraldehyde is an effective reductant and only 1.2 equivalent of isobutyraldehyde to α-pinene is needed to ensure high yield of α-pinene oxide. The catalyst is also very stable and can be reused at least eight times without loss of its activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296000
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Acid Rain and Below-Cloud Scavenging in South-Western China (1997)
    Springer
    Journal of atmospheric chemistry 27 (1997), S. 71-78 
    Details
    ISSN: 1573-0662
    Keywords: washout ; scavenging ; Southern China ; sulphur dioxide ; acid rain ; simulation ; aerosol ; cloudwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Major urban areas in south-western China exhibit unique air pollutionproblems due to increasing use of high sulphur-content fuels in an environmentof unfavourable topography and climate. Ambient levels of sulphur dioxideexceed the air quality objectives, and this gas is the major precursor of acidrain. Cloudwater chemistry studies are reported for urban, suburban andcountryside locations, during the period 1985–1989. Although cloudwateracidity was found to increase towards the cloud base, the acidity was muchgreater for rainwater samples collected simultaneously, and was morepronounced in urban rather than neighbouring suburban or countryside regions.The main contribution to the acidity arises from below-cloud scavenging of gasand aerosol and model calculations are able to simulate this behaviour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005852700933
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Catalytic behavior of a magnesium oxide supported polysilazane-ruthenium complex for the oxidation of indene with molecular oxygen to indanones (1996)
    Springer
    Reaction kinetics and catalysis letters 57 (1996), S. 147-152 
    Details
    ISSN: 1588-2837
    Keywords: MgO support ; polysilazane ruthenium (0) complex ; oxidation of indene to indanones ; molecular oxygen ; XPS analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new magnesium oxide supported polysilazane ruthenium complex has been prepared and found to be capable of catalyzing the oxygenation of indene in 62.9% conversion to indanones without by-products under mild conditions, i.e. 1 atm oxygen and 80°C. The supported ruthenium complex was effective without need for a cocatalyst. Also, it can be reused several times without apparent loss of activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02076133
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Molecular structure of liquid-crystalline copolyesters of vanillic acid, 4-hydroxybenzoic acid and poly(ethylene terephthalate) (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 227 (1995), S. 69-85 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Thermotrop flüssigkristalline Copolyester aus Vanillinsäure (V), 4-Hydroxybenzoesäure (B) und Polyethylenterephthalat (E) wurden mittels 1H-NMR-Spektroskopie und Gelpermeationschromatographie (GPC) untersucht. Die neun möglichen Diaden konnten detektiert und zugeordnet werden. Die Abfolge der Grundeinheiten der V/B/E-Copolyester ändert sich mit zunehmendem B-Anteil von statistischer Verteilung zur Blockbildung und ist außerdem geringfügig von der Katalysatorkonzentration und der Polykondensationsdauer abhängig. Die GPC-Ergebnisse deuten darauf hin, daß die V/B/E-Copolyester engere Molekulargewichtsverteilungen aufweisen als die B/E-Copolyester. Mit von 0 bis 5 mol-% steigendem V-Anteil verengt sich die Molekulargewichtsverteilung. Die Gelpermeationschromatogramme der meisten V/B/E-Copolyester weisen im Unterschied zu den Einzelsignalen der B/E-Copolyester Dublett-Peaks auf.
    Notes: Thermotropic liquid-crystalline copolyesters made from vanillic acid (V), 4-hydroxybenzoic acid (B) and poly(ethylene terephthalate) (E) were examined by 1H-NMR and GPC investigations. Nine possible diads could be identified and assigned. The sequence distribution of V/B/E copolyesters tends to change from random to block with an increase of B content in the copolyesters. The sequence distribution also varies slightly with catalyst concentration and polycondensation time. GPC results suggest that the V/B/E copolyesters have narrower molecular weight distribution (MWD) than B/E copolyesters. The MWD of the copolyesters narrows gradually with increasing V content from zero to 5 mol-%. The GPC chromatograms of the most V/B/E copolyesters show double peaks, which is different from the single peak of the GPC chromatograms of the B/E copolyesters.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1995.052270108
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...