Effects of crystallographic ordering on the magnetic behaviour of (AgIn)1-zMn2zTe2 and (CuIn)1-zMn2zTe2 alloys

Measurements of magnetic susceptibility in the temperature range 4.2–300 K were made on polycrystalline samples of the (AgIn)_{1 - z}Mn_2zTe₂ and (CuIn)_{1 - z}Mn_2zTe₂ alloys, and the data used to give values of spin-glass transition te mperature T_g and Curie-Weiss paramagnetic temperature θ. For any sample for which the X-ray powder photograph indicated an apparently single phase condition, either zinc-blende or chalcopyrite, the susceptibility data could show up to three separate T_g values. These different magnetic conditions are attributed to crystallographic ordering of the Mn ions on the chalcopyrite and zinc-blende lattices, the three observed T_g values corresponding to disordered zinc-blende, ordered zinc-blende and ordered chalcopyrite. The value of θ obtained from the 1/χ vs. T plot is shown to be a weighted mean of the separate values of θ for the phases present. The relative sizes of the T_g peaks and the values of θ for any given sample gives an indication of the amount of each phase present. These amounts were varied by using different methods of heat treatment and it was shown that the magnetic behaviour was consistent with the T(z) phase diagram for the two alloy systems.     

DK UK10-A系列音箱

UK10-A系列适用于各种固定安装的高档演艺吧、慢摇吧及现场表演。该系列采用高功率扬声器单元和轻巧的箱体搭配，通过计算机优化设计，达到平滑的特性、展宽的频响特点和良好的控制覆盖性能。     

养分胁迫条件下石斛兰叶片 表面结构的电镜观察

本文运用扫描电镜(SEM)技术，对石斛兰在养分胁迫条件下叶片的表面结构作了扫描观察。发现当养分胁迫时，叶表面角质层花纹发生改变，叶片气孔形状，数量均受养分营养状况的制约。缺S时叶片角质层被剥蚀，缺K时叶片表面有结晶状物质。     

光电化学法测定硅中少子扩散长度

本文将Gartener方程应用于硅材料,并提出了称之为I_o/I_(ph)-α~(-1)法的光电化学法,用于测定硅中少子扩散长度.文中研究了实验条件对测量结果的影响,讨论了该法的实用价值和给出了与SPV法对比的实验结果.     

Co dissociation and recombination reactions on Ni(100)

The kinetics of atomic carbon and oxygen buildup on a Ni(100) surface exposed to carbon monoxide at high temperatures have been investigated by Auger electron spectroscopy. The experimental data, taken at different sample temperatures (453 , T 573 K) and at different CO partial pressures (3 ×10⁻⁷ , P_co , 3 ×10−1</sup> mbar) allowed the identification of the CO dissociation mechanism. By fitting the experimental data with a set of rate equations describing CO dissociation, CO reduction of surface oxygen, and C and O recombination, we have been able to determine the pre-exponential factors and the activation energies of these processes.</sup>     

Infrared spectra of edge-shared silicate tetrahedra

Dehydroxylated silica exhibits two well-defined infrared bands at 888 and 907 cm⁻¹ previously assigned to a highly reactive strained surface defect. Comparisons of the spectra of dehydroxylated silica to frequencies and intensities calculated using molecular orbital (MO) calculations and to spectra obtained for cyclodisiloxanes suggest that the strained surface defect consists of an edge-shared silicate tetrahedral ring. Changes in vibrational frequencies and peak intensities with 18</sup>O labeling for both the surface defect and the cyclodisiloxanes are consistent with those expected for ring vibrational modes. The IR bands associated with the strained edge-shared ring disappear when either the surface defects or the cyclodisiloxanes react with water. Reactions of the surface defect can be used to study how strain enhances the reactivity of Si-O-Si bonds for modeling phenomena such as stress corrosion cracking.</sup>     

Electron transport in semiconductors under a strong high frequency electric field

We propose an analytical approach to study the electron transport in semiconductors when a strong high frequency (HF) electric field is applied together with a weak direct current (DC) electric field. We derive a set of dynamic equations, from which the amplitude and phase of each harmonic component of the electron drift velocity and the electron temperature can be obtained. Our calculation shows that the DC conductivity in an n-GaAs sample decreases dramatically with increase of the first and second harmonic applied electric fields and definitely becomes negative.     

Advances in Silicon Resonant Pressure Transducers

This paper presents a MEMS Resonant Pressure Transducers (RPT) that is produced using a flexible fabrication route to allow pressure ranges from 1bar to 700bar in fully oil isolated hermetic packages without compromising sensor performance. The fabrication method makes use of silicon fusion bonding (SFB) and deep reactive ion etching (DRIE) to build up a three-layer die, with the middle layer consisting of a strain sensitive resonator. The key aspects of the fabrication process and sensor design that make this possible are presented, along with data showing long-term stability of better than 100ppm drift per year.     

宽带IP城域网及其应用

文章结合南京电信公众宽带IP城域网的建设，对宽带IP城域网的网络结构、用户接入安全、网络管理和认证计费作了阐述，并简要介绍了应用于宽带IP城域网上的一些业务。