High concentration erbium doping of silicon-rich SiO2 thin films on silicon

In this work, high concentration erbium doping in silicon-rich SiO₂ thin films is demonstrated. Si plus Er dual-implanted thermal SiO₂ thin films on Si substrates have been fabricated by using a new method, the metal vapor vacuum arc ion source implantation with relatively low ion energy, strong flux and very high dose. X-Ray photoelectron spectroscopy measurement shows that very high Er concentrations on the surfaces of the samples, corresponding to 10 at.% or the doping level of 10²¹ atoms cm⁻³, are achieved. This value is much higher than that obtained by using other fabrication methods such as the high-energy ion implantation and molecular beam epitaxy. Reflective high-energy electron diffraction, atomic force microscopy and cross-section high-resolution transmission electron microscopy observations show that the excess Si atoms in SiO₂ matrix accumulate to form Si clusters and then crystallize gradually into Si nanoparticles embedded in SiO₂ films during dual-ion implantation followed by rapid thermal annealing. Er segregation and precipitates are not formed. Photoluminescence at the wavelength of 1.54 μm exhibits very weak temperature dependence due to the introduction of Si nanocrystals into the SiO₂ matrix. The 1.54-μm light emission signals from annealed samples decrease by less than a factor of 2 when the measuring temperature increases from 77 K to room temperature.     

SMF-425树脂吸附和解吸铼的研究

研究了SMF-425型阴离子交换树脂在弱酸体系中吸附、解吸铼的性能和机理，结果表明，[H^ ]在0.1～1.0mol/L范围内，对铼的吸附有利，吸附平衡服从Freundish吸附等温式，吸附反应吸热，温度越高越有利于吸附。每g干树脂对铼的静态和动态饱和吸附容量分别为169.31mg、175.43mg。用2mol/L硫氰酸铵作淋洗剂，流速为2mL/min时，淋洗效果较好，结果令人满意。     

电子商务对企业集团营销手段的影响

介绍了电子商务，以及目前电子商务的发展趋势及对社会的影响，特别阐述了蓬勃发展的电子商务对企业集团的经营环境与手段的影响。     

抽余C_4烃中异丁烯催化逆流水合制叔丁醇

采用大颗粒离子交换树脂催化剂,在φ100mm×10m的反应器中进行了异丁烯催化逆流水合制叔丁醇的中间试验。考察了反应温度、水油体积比和抽余C4烃的流速等对异丁烯转化率的影响。试验结果表明,异丁烯催化逆流水合制叔丁醇的适宜操作条件为:反应温度80~90℃,水油体积比为4~5,抽余C4烃的流速为0.45~0.55mm/s。在此条件下,异丁烯的转化率可达88.8%。工业装置运转结果表明,异丁烯转化率大于75%。     

A new alloy design concept for austenitic stainless steel with tungsten modification for bipolar plate application in PEMFC

The feasibility of a new alloy design concept utilizing the principle of ‘tungsten bronze effect’ is critically evaluated for the development of metallic bipolar plates for proton exchange membrane fuel cell (PEMFC). An austenitic stainless steel (ASS) is modified with W and La to improve the stability of the passive film in an acidic environment as well as to reduce the contact resistance by the tungsten bronze effect. The experimental ASS containing W and La was evaluated in a simulated PEMFC environment of H₃PO₄ and H₂SO₄ solutions at 80 °C, and the electrical property was evaluated by performing a contact resistance test. The test results show that the ASS modified with W and La has good passive film stability for corrosion resistance and low contact resistance. The X-ray photoelectron spectroscopy (XPS) analysis clearly suggests the possibility of the tungsten bronze effect from the change in valency state of W⁶⁺ to W⁵⁺ in the passive film formed on the modified ASS. The feasibility of a new alloy design concept utilizing the ‘tungsten bronze effect’ is well demonstrated; however, more study is highly required for the development of metallic bipolar plates of PEMFC.     

程控电话交换机过电流保护元件用高性能PTC陶瓷的研制

阐述了高性能ＰＴＣ陶瓷材料制备的基本要点，并以基方固溶体化学组成、原材料选择、复合添加物改性以及特定烧结工艺等方面开展工作，制得了居里温度为９０℃左右、室温体积电阻率为３０Ω·ｃｍ，电阻率突变ρνｍａｘ／ρνｍｉｎ＞１０５、电阻率温度系数α≈１５％／℃、耐电压强度≥１５０Ｖ／ｍｍ的高性能ＰＴＣ陶瓷材料。此材料制得的元件能满足程控电话交换机过电流保护的要求。     

10W QCW operation of a proton implanted GaAlAs diode laser array

We report one thick layer of hard-baked photoresist mask.The laser array stripe pattern was defined by standard wet lithography.With this mask, a 10 W QCW(quasi-continuous wave) operation of a narrow proton implanted multiple stripe conventional single quantum well separate confinement heterostructure(SQW-SCH) GaAlAs diode laser array has been realized.These devices exhibit the lateral far-field radiation pattern of a phase-locked array of gain-guided semiconductor injection laser array. The twenty stripe laser array has a lateral far-field beam divergence full width at half maximum (FWHM) of less than 3°, and three twenty stripe laser array has a beam divergence in the plane of the junction of about 9°.     

Modelling the dynamics of multicomponent ion exchange with dissimilar diffusivities of components

The dynamics of multi-ion exchange is investigated with consideration for electric fields arising in sorbents when the ions with distinct diffusivities are exchanged. A new model for this process is developed. Simulation shows that the electric field can affect the dynamic break-through curves. The proposed model can be used for the creation of a new process of sorbents regeneration and microcomponents concentration.     

Macroscopic model for multispecies ion-exchange kinetics

A model for multispecies ion-exchange kinetics based on the Nernst-Planck equation is suggested. It is analyzed in comparison with the “locally-determinate” model described by Hwang and Helfferich [1]. The model makes possible simple computation. The conditions for the occurrence of unusual kinetic curves with a maximum are clarified. The proposed model is developed for different types of kinetic problems and verified by the experimental investigation of a kinetics in ternary systems.