New bowl-shaped columnar liquid crystals
A series of bowl-shaped dodeca-alkanoyloxy macrocyclic derivatives (1) is described; four compounds of this series (1c–g) display a Dho columnar mesophase.
Materials Literature
文献浏览
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Reaction mechanism of Escherichia coli cystathionine .gamma.-synthase: direct evidence for a pyridoxamine derivative of vinylgloxylate as a key intermediate in pyridoxal phosphate dependent .gamma.-elimination and .gamma.-replacement reactions
Cystathionine gamma-synthase catalyzes a pyridoxal phosphate dependent synthesis of cystathionine from O-succinyl-L-homoserine (OSHS) and L-cysteine via a gamma-replacement reaction. In the absence of L-cysteine, OSHS undergoes an enzyme-catalyzed, gamma-elimination reaction to form succinate, alpha-ketobutyrate, and…
Measurement of thermal conductivity of polymer melts by the line‐source method
Abstract An apparatus has been developed for the measurement of thermal conductivity of polymer melts. Based on the transient “line source method,” it is ideally suited to these materials because measurements can be made quickly, before the onset of thermal degradation. Also, little or no sample preparation is require…
Diffusion of Chromium in α-Iron
Tracer diffusion coefficient of 51Cr in α-iron has been determined by a serial radio-frequency sputter-microsectioning method in the temperature range 885 to 1174 K. In α-iron of the paramagnetic state from the Curie temperature to the α-γ transformation temperature the diffusion coefficient of chromium shows a linear…
Epitaxial growth of transition metal dichalcogenides on cleaved faces of mica
We have grown ultrathin films of layered transition metal dichalcogenides (MoSez,NbSe z ) heteroepitaxially on cleaved faces of mica (muscovite).This is the first success in the heteroepitaxial growth between highly heterogeneous layered materials having different crystal structures and lattice constants that differ b…
Alternating current impedance study of a polypyrrole-based anion-exchange polymer
The ac impedance of poly-[1-methyl-3-(pyrrol-1-ylmethyl)pyridinium]+(poly-MPMP+) as a function of potential has been investigated in acetonitrile solutions. When the polymer is reduced it acts merely as a barrier to the migration of ions to the double layer of the underlying electrode. Thus the ionic conductivity of t…
The Amino Acid Composition of Major Ampullate Gland Silk (Dragline) of Nephila Clavipes (Araneae, Tetragnathidae)
(Uploaded by Plazi from the Biodiversity Heritage Library) No abstract provided.
Corrosion of Iron in Gaseous Environments and in Gas-Saturated Aqueous Environments
The corrosion of alloy 4130 (UNS(1) G41300) steel has been investigated at temperatures up to 400°F in gaseous environments containing varying amounts of H2S and CO2 and in gas-saturated aqueous environments having dissolved chlorides. Thermogravimetric techniques have been used for establishing the kinetics of corros…
Nickel and Nickel Alloys
Abstract Nickel in elemental form or alloyed with other metals and materials has made significant contributions to our present-day society and promises to continue to supply materials for a demanding future. This article provides a historical overview and physical metallurgy of nickel and nickel alloys. It lists and d…
Wrought Stainless Steels
Abstract This article discusses the composition, characteristics, and properties of the five groups of wrought stainless steels: martensitic stainless steels, ferritic stainless steels, austenitic stainless steels, duplex stainless steels, and precipitation-hardening stainless steels. The selection of stainless steels…
Specific properties of amphiphilic particles at fluid interfaces
We present a theoretical and experimental study of amphiphilic particles : these are small solid spheres treated so that one part of the solid is hydrophilic whereas the other is hydrophobic. These beads have a specific behaviour at the interface between two fluids of different polarities since they are anchored at th…
Electronic structure of poly(tetrafluoroethylene) studied by UPS, VUV absorption, and band calculations
Electronic structure of poly(tetrafluoroethylene) studied by UPS, VUV absorption, and band calculations, Kazuhiko Seki, Hiroshi Tanaka, Toshiaki Ohta, Yuriko Aoki, Akira Imamura, Hitoshi Fujimoto, Hiromichi Yamamoto, Hiroo Inokuchi
Capacitors
A review of capacitor fundamentals and technology that is intended for the clarification of the modes of operation of the broad spectrum of capacitors, including paper/polymeric films, electrolytics, and ceramics, is presented. How each class of capacitor performs in both low- and high-power electronics is discussed i…
Preisach modeling and reversible magnetization
Methods of dealing with reversible magnetization in the context of Preisach modeling are examined. A generalization of the vector product model which includes reversible effects, as well as the usual irreversible effects, is presented.>
Oxidation reaction of [{Cu(Hpz) 2 Cl} 2 ](Hpz = pyrazole): synthesis of the trinuclear copper( II ) hydroxo complexes [Cu 3 (OH)(pz) 3 (Hpz) 2 Cl 2 ]·solv (solv = H 2 O or tetrahydrofuran). Formation, magnetic properties, and X-ray crystal structure of [Cu 3 (OH)(pz) 3 (py) 2 Cl 2 ]·py (py = pyridine)
The trinuclear copper(II) complexes [Cu3(OH)(pz)3(Hpz)2Cl2]·solv (Hpz = pyrazole, pz = pyrazolate anion, solv = H2O or tetrahydrofuran) have been obtained by oxidation reactions of [{Cu(Hpz)2Cl}2]. When treated with pyridine(py), both CuII derivatives gave the related compound [Cu3(OH)(pz)3-(py)2Cl2]·py, which has bee…
Acoustic diagnosis of gas insulated substations: a theoretical and experimental basis
Loose particles and discharges inside the ducts of a gas-insulated substation (GIS) are considered hazardous to the insulation system. These irregularities or flaws can be detected by using acoustic sensors placed on the enclosure. An elementary review of sound propagation in a GIS together with corresponding experime…
Atomic mechanisms of mass transport in ceramic nuclear fuel materials
A critical review is given on self-diffusion, impurity diffusion, chemical diffusion, thermal diffusion and radiation-enhanced diffusion in the ceramic nuclear fuels, i.e. oxides, carbides, nitrides and carbonitrides of uranium and plutonium. Atomic transport in ThO2 is also discussed. Besides experimental results on…
Chromogenic materials for transmittance control of large-area windows
Chromogenic materials have optical properties that can be changed in a persistent and reversible manner under the action of an external stimulus. They can regulate the throughput of radiant energy between widely separated extrema, and hence they can be used in future “smart windows” in buildings, cars, etc., and for m…
Sedimentation dynamics and redox iron-cycling: controlling factors for the apatite—glauconite association on the East Australian continental margin
Abstract Detailed sedimentological and geochemical studies of phosphorites and sediments from the East Australian continental margin have shown that both apatite and glauconite are forming at a transition zone between relict, iron oxyhydroxide-rich, organic-poor (TOC<0.3%) outer shelf (200–350 m) sediments and relativ…
A Simulation of the Draping of Bidirectional Fabrics over Arbitrary Surfaces
The development of a graphical simulation to describe the draping of bidirectional fabrics over arbitrary surfaces is reported. The simulation applies to any surface, described either analytically or numerically, and allows any number of draped configurations on a surface. A unique draped configuration results when on…