Materials Literature
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A comparative study of the electronic structures and conduction properties of the three heterocyclic polymers polypyrrole, polythiophene, and polyfuran has been carried out using the results of ab initio crystal orbital calculations. Important electronic properties such as band gap, bandwidths, ionization potential, a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOptical Isomer Separation by Liquid ChromatographyDaniel W. ArmstrongCite this: Anal. Chem. 1987, 59, 2, 84A–91APublication Date (Print):January 15, 1987Publication History Published online30 May 2012Published inissue 15 January 1987https://pubs.acs.org/doi/10.1021/ac00129a7…
In this paper a one-dimensional analysis is presented that leads to the appropriate equation of motion for the undeformed portion of a plastic, rigid rod after impact with a rigid anvil. This equation is used as a basis for deducing material properties of the rod material from post-test measurements.
An energetic study of the excitation spectrum in doped polythiophene is presented within the framework of the H\"uckel approximation. The calculations show that localized states like polarons and bipolarons are produced by doping, the formation of doubly charged bipolarons being energetically more favorable than the f…
New expressions are presented, simplified, and discussed for the small-signal-frequency response of systems involving distributions of activation energies with either exponential or Gaussian probability densities. The results involve the possibility of separate but related thermal activation of energy-storage and ener…
The electronic properties of a tight-binding model which possesses two types of hopping matrix element (or on-site energy) arranged in a Fibonacci sequence are studied. The wave functions are either self-similar (fractal) or chaotic and show ``critical'' (or ``exotic'') behavior. Scaling analysis for the self-similar…
The inelastic electron mean free path as a function of energy is calculated for Cu, Ag, Au, and Al. The calculations are based on a model dielectric function \ensuremath{\epsilon}(q,\ensuremath{\omega}), which is obtained from a modification of the statistical approximation. In this approach \ensuremath{\epsilon}(0,\e…
Te-Ge-Sn-Au thin films were studied for phase change type rewritable disk media, in order to obtain the fast crystallization speed and the thermal stability. Films were prepared by co-evaporation method. It was found that through static record/erase measurements the threshold crystallizing pulse duration of Te60Ge4Snl…
Any desired surface wettability of a plastic surface can be produced by changing the concentration of the plasma gas, which here is a mixture of oxygen and a compound which includes fluorine. In the plasma treatment, the use of a third electrode consisting of a metal mesh for ion trapping can significantly decrease th…
This paper describes some of the yarn deformations and relative movements between yarns which occur when an isolated yarn is pulled through 20 crossover yarns out of an untreated cotton weave which has a relatively open and regular structure. The described deformations are of two kinds: linear extension in the selecte…
Spectroscopic and electrochemical studies, incorporating electronic spectra, electron paramagnetic resonance (EPR) spectra, resonance Raman (RR) spectra, and measurements of the redox potential, have been carried out on the blue copper protein azurin, from Alcaligenes denitrificans. These data are correlated with the…
A tight-binding version of the itinerant spin-fluctuation theory is used to describe the electronic structure of MnTe in both magnetically ordered and disordered phases. The static model of disordered local moments is shown to be sufficiently accurate to form the basis for a quantitative description of semiconducting…
Photoluminescence from the neutral vacancy in diamond is shown to have a radiative decay time tau =2.55+or-0.1 ns in the limit of low temperature, for photon excitation at energies 1.8<hv<3 eV. With increasing T, tau decreases. The quantum efficiency is estimated to be only about 1.5% even at low T. Detailed-balance a…
The MerR protein mediates the induction of the mercury resistance phenotype in bacteria; it has been isolated in order to study the effects of metal-ion induced changes in the metabolism of prokaryotic cells at the molecular level. After DNA sequences responsible for negative autoregulation were removed, the 16-kiloda…
Abstract In electron scattering measurements of the Compton profiles of solids, multiple scattering events contribute strongly to the observed profile. The dominant contribution to the multiple scattering arises from events in which Bragg scattering is followed by Compton scattering. The Bragg scattering is calculated…
Quantum mechanical calculations of the surface stress tensor at the aluminum (111) and (110) surfaces are presented. In each case the stress is tensile, favoring contraction in the plane of the surface. This tensile stress is caused by smoothing of the electronic wave functions at the crystal surface.
It is shown by model calculations that the dispersion of the diagonal part of the dielectric constant near the plasma edge in a metallic crystal has a strong influence on the magneto-optical properties. The plasma edge leads to resonancelike peaks in the Kerr rotation and Kerr ellipticity spectra and to a strong enhan…
摘要 结合快离子导体玻璃的结构特点和倪嘉陵(Ngai) 的低能激发、弛豫、耗散统一理论, 依据非Markov 方程探讨了快离子的输运特点, 导出了非晶态快离子导体电导的频率一温度依赖关系. 理论方法与现有快离子导体电导理论不同, 结果表明与实验数据符合较好, 理论能较好地描述低温下电导的色散现象. 色散的程度与表征物质内部结构差异的参数— 红外发散指数n有关. Abstract Based on the characteristics of superionic glasses and a physical picture of unified theory of the low-frequency fluctuation, di…
3BaO·3B2O3·2GeO2 is a new compound in the ternary system BaO-B2O3-GeO2. Its crystallization process has been studied by means of thermoanalysis method. The temperature of crystallization decreases distinctly with decrease of the grain size. The activation energy of crystallization of the amorphous material with differ…
少量溶液の取り扱いに有利な重量基準による標準添加法を原子スペクトル分析法と組み合わせて検討した.従来の容量基準による方法と異なり,試料溶液の分取量,標準溶液の添加量,最終溶液量をそれぞれ正確に一定にする必要はなく,試料溶液の希釈率を補正係数として用いることにより従来法となんら変わりなく標準添加法を適用することができ,正確さ及び再現性とも良好であった.本法をアルミニウム合金(NBS 87a,NKK 916)及び99.99%アルミニウム中のマグネシウムのAAS定量及び標準岩石(GSI-JG-1)中のリチウムのICP-AES定量に応用し,良好な結果を得た.