Materials Literature
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The preparation of suitably large protein single crystals is essentially the rate-determining step of protein x-ray structure determinations. Attempts to produce single crystals with two model compounds-beta-galactosidase and lysozyme-under conditions of microgravity were successful. Crystals formed by salting out fro…
Thermally induced surface-driven convection (thermal Marangoni convection) was investigated in the Spacelab 1 microgravity environment. The configuration studied is related to the floating-zone technique used for crystal growth.
The majority- and minority-spin states of the exchange-split virtual bound state of Mn impurities in Cu and Ag are studied with high-resolution photoemission and bremsstrahlung isochromat spectroscopy. The exchange splitting is found to be close to the atomic value. The majority-spin state is strongly hybridized with…
Abstract Applying Hill’s self-consistent method to finite elastic-plastic deformations, we estimate the overall moduli of polycrystalline solids. The model predicts a Bauschinger effect, hardening, and formation of vertex or corner on the yield surface for both microscopically non-hardening and hardening crystals. The…
The 1,4‐β‐D‐glucan cellobiohydrolase I (CBHI) from Trichoderma reesei was labelled with 4–6 nm gold particles. This CBHI‐gold complex still retains 60% of the original CBHI activity and allows good visualization of the enzyme adsorbed at the surface of cellulose mirofibrils or microcrystals. The main features of the a…
An internal photoemission experiment which yields the energy-dependent momentum-and energy-loss rates of hot electrons is designed. The results on solid hydrocarbon films are analyzed in terms of the appropriate Boltzmann equation. Band mobilities are obtained for hot electrons. Their energy-loss rate has a maximum at…
The (heretofore unknown) crystal structure of lithium at low temperature is identified to be close-packed rhombohedral $9R$. The stacking order of the hexagonal layers is $ABCBCA\ensuremath{-}CAB$, a nine-layer repeat sequence. There are three atoms per primitive rhombohedral cell, and nine in the (nonprimitive) hexag…
An investigation has been carried out to study changes in shape on aging in plastic deformed Ag-Pd-Au-Cu alloys. The changes in shape were measured in order to establish a relationship to the aging heat treatments. Their microstructure was observed in order to clarify this phenomenon at the same time. They were also i…
In this paper we briefly discuss the operation of the silicon intensified target (SIT) vidicon, describing what we conclude to be the most important properties of the detector. We provide experimental evaluation of the SIT vidicon characteristics, including two-dimensional image fidelity, channel-to-channel and pixel-…
Thermal conductivity (A) data for two dense Cr 2 O 3 samples are reported. The results, which span the temperature range 270 to 360 K, show an inflection near the Neel transition temperature, 308 K. An analysis shows that the slope of the higher‐temperature portion of the λlD −1 −T curve is about what would be expecte…
The effect of several chemical and physical treatments for PbTe(100) surface cleaning was investigated by XPS. Etching with a (NH4OH+H2O2) solution shows a remarkable contrast to etching with acid, the first one being suitable to eliminate carbon contamination. The combination of the (NH4OH+H2O2) etching, heating and…
Abstract Eine Apparatur zur Untersuchung der Spannungsrißkorrosion von Stahlen in flüssigem Ammoniak unter definierten elektrochemischen Bedingungen wurde aufgebaut. Ein Rechner steuerte den Versuchsablauf und registrierte die Meßdaten. Die dazu nötigen Programme wurden entwickelt. Versuche mit Rundproben aus Schweißs…
Abstract The voltage lifetime of a poly(ethylene terephthalate)/glass composite is measured for two different orientations of short fiber with respect to the applied electric field (perpendicular and parallel). The difference in the voltage lifetime between two configurations is attributed to the microstructural featu…
Summary Monitoring of microbial corrosion is always difficult because of the sessile nature of bacteria and the lack of meaningful correlation between routine bacteria counts and bacterial activity. This problem is further aggravated in a large oilfield water system because of size and sampling difficulties. This pape…
We calculate the electric conductivity of a system consisting of parallel layers of insulator, embedded into a uniform conductor. Each layer is perforated by holes, which are arranged on a two-dimensional hexagonal lattice. We investigate various stacking patterns of the layers, in volume fractions of 40% to 50%. The…
Abstract The phthalide‐containing epoxy resins are synthesized and characterized in comparison with the bisphenol‐A epoxy resins in terms of thermal properties. Although both resins contain comparable amounts of halogens, the resulting flame retardancy is higher in the phthalide‐containing resin. The char formation up…
Birefringence, densite, mesures en calorimetrie differentielle a balayage, mesures de retrait
Measurements were made of working level ratios and the effective diffusion constants of radon daughters using a special housing designed to provide a uniform diffusional environment at the passive detectors. For 2 of 7 exposures, the measured scale of the diffusion was too large to satisfy the uniformity requirement.…
Abstract Phase separation behavior has been studied in aqueous solutions of partially butyralized poly(vinyl alcohol) (BuPVA) with various degrees of butyralization x Bu and various molecular weights. It is found that these systems exhibit both upper and lower critical solution temperatures. The theta temperatures θ L…
SUMMARY The combination of a scanning electron microscope and a microcomputer can be used to carry out automatic, quantitative, morphological analysis of a wide range of samples. A system implemented around a commercially available 8‐bit computer and interface hardware is described. Computerized analysis of shape is m…