Effect of aging temperature on the microstructures and mechanical properties of ZG12Cr9Mo1Co1NiVNbNB ferritic heat-resistant steel

The effect of aging on the mechanical properties and microstructures of a new ZG12Cr9Mo1Co1NiVNbNB ferritic heat resistant steel was investigated in this work to satisfy the high steam parameters of the ultra-supercritical power plant. The results show that the main precipitates during aging are Fe(Cr, Mo)₂₃C₆, V(Nb)C, and (Fe₂Mo) Laves in the steel. The amounts of the precipitated phases increase during aging, and correspondingly, the morphologies of phases are similar to be round. Fe(Cr, Mo)₂₃C₆ appears along boundaries and grows with increasing temperature. In addition, it is revealed that the martensitic laths are coarsened and eventually happen to be polygonization. The hardness and strength decrease gradually, whereas the plasticity of the steel increases. What’s more, the hardness of this steel after creep is similar to that of other 9%–12%Cr ferritic steels. Thus, ZG12Cr9Mo1Co1NiVNbNB can be used in the project.     

A study on poly (N-vinyl-2-pyrrolidone) covalently bonded NiTi surface for inhibiting protein adsorption

Near equiatomic NiTi alloys have been extensively applied as biomaterials owing to its unique shape memory effect, superelasticity and biocompatibility. It has been demonstrated that surfaces capable of preventing plasma protein adsorption could reduce the reactivity of biomaterials with human blood. This motivated a lot of researches on the surface modification of NiTi alloy. In the present work, following heat and alkaline treatment and silanization by trichlorovinylsilane (TCVS), coating of poly (N-vinyl-2-pyrrolidone) (PVP) was produced on the NiTi alloy by gamma ray induced chemical bonding. The structures and properties of modified NiTi were characterized and in vitro biocompatibility of plasma protein adsorption was investigated. The results indicated that heat treatment at 823 K for 1 h could result in the formation of a protective TiO2 layer with “Ni-free” zone on NiTi surface. It was found that PVP was covalently bonded on NiTi surface to create a hydrophilic layer for inhibiting protein adsorption on the surface. The present work offers a green approach to introduce a bioorganic surface on metal and other polymeric or inorganic substrates by gamma irradiation.     

Effects of doping in 25-atom bimetallic nanocluster catalysts for carbon–carbon coupling reaction of iodoanisole and phenylacetylene

We here report the catalytic effects of foreign atoms (Cu, Ag, and Pt) doped into well-defined 25-gold-atom nanoclusters. Using the carbon-carbon coupling reaction of p-iodoanisole and phenylacetylene as a model reaction, the gold-based bimetallic MxAu25?x(SR)18 (–SR=–SCH2CH2Ph) nanoclusters (supported on titania) were found to exhibit distinct effects on the conversion of p-iodoanisole as well as the selectivity for the Sonogashira cross-coupling product, 1-methoxy-4-(2-phenylethynyl)benzene). Compared to Au25(SR)18, the centrally doped Pt1Au24(SR)18 causes a drop in catalytic activity but with the selectivity retained, while the AgxAu25?x(SR)18 nanoclusters gave an overall performance comparable to Au25(SR)18. Interestingly, CuxAu25?x(SR)18 nanoclusters prefer the Ullmann homo-coupling pathway and give rise to product 4,4′-dimethoxy-1,1′-biphenyl, which is in opposite to the other three nanocluster catalysts. Our overall conclusion is that the conversion of p-iodoanisole is largely affected by the electronic effect in the bimetallic nanoclusters’ 13-atom core (i.e., Pt1Au12, CuxAu13?x, and Au13, with the exception of Ag doping), and that the selectivity is primarily determined by the type of atoms on the MxAu12?x shell (M=Ag, Cu, and Au) in the nanocluster catalysts.     

固定化磷钨酸催化合成柠檬酸三丁酯

研究了Sol—gel固定化磷钨酸催化柠檬酸和正丁醇合成柠檬酸三丁酯，结果显示：最佳反应条件为：酸醇摩尔比1：4，催化剂用量2．5％(磷钨酸与柠檬酸质量比)，反应时间3．5h，反应温度140～145℃，柠檬酸三丁酯的产率大于95％，催化剂重复使用7次，产率仍达87％以上。     

Cathodic micro-arc electrodeposition of yttrium stabilized zirconia (YSZ) coatings on FeCrAl alloy

Zirconia-based coatings, especially yttrium stabilized zirconia (YSZ), are the best ceramic coatings for high temperature applications due to their superior mechanical and thermal behavior[1]. And YSZ is of considerable in-terest for applications in solid-oxide fuel cells due to its high oxygen-ion conductivity and stability in oxidizing and reducing atmospheres, oxygen sensors and microelec-tronic devices[2]. The traditional methods to produce the YSZ coatings are plasma spray, electron be…     

Broadcast Scheduling Strategy Based on the Priority of Real-Time Data in a Mobile Environment

Data broadcast is an important data dissemination approach in mobile environment. On broadcast channel, scalability and efficiency of data transmission are satisfied. In a mobile environment, there exists a kind of real-time database application in which both the transactions and data can have their timing constraints and priorities of different levels. In order to meet the requirement of real-time data disseminating and retrieving, a broadcast scheduling strategy HPF-ED F (Highest Priority First with Earlier Deadline and Frequency) is proposed under the BoD (Broadcast on Demand) model. Using the strategy, data items are scheduled according to their priority the transaction imposed on them or system set for them. The strategy also considers other characteristics of data items such as deadline and popularity of data. The extensive simulation experiments have been conducted to evaluate the performance of the proposed algorithm. Results show that it can achieve excellent performance compared with existing     

桁架结构智能布局优化系统

应用模糊、混沌、神经网络等理论，以结构质量为优化目标函数，在构造一个新型的布局优化模型的基础上，对桁架结构布局优化这一结构优化领域的难点问题进行了研究。构造了一个完整的桁架结构智能布局优化系统，该系统由5 个模块组成，具有智能、自适应的特点，在确定了结构选型情况下，可以自动完成从基结构的智能自动建立到结构布局寻优的全过程。经实例验证，系统性能稳定，可以得到满足要求的结构布局优化解。     

THE STUDY OF UV-PHOTOCHROMIC ANTI-COUNTERFEIT PAPER

1.INTRODUCTIONAt present, the anti-counterfeit paper technique is usually includes two kinds: one is to anti-counterfeit the paper itself, such as watermark, safety line, putting some special material into the pulp; the other one is the applications of printing and computer-laser-info-icon onto the paper which was regarded as the anti-counterfeit medium. Anti-counterfeit is significant to the national economy due to its safeguard to the currency, bill, certificates and so on, but also to s…     

Territorial Features of Atmospheric Environment in Beijing and Impact of Dust-storm

1Introduction　TheenvironmentproblemsontheEarthcanbeclassifiedasthreekinds ,whicharecalledasthelocalenvironment,terri torialenvironmentandglobalenvironmentproblems ,respec tively .Nowthekindsofanthropogenicactivityhaveledtotheseriousterritorialenvironmentproblemsallovertheworld .Recently ,theterritorialenvironmentproblemsinChinahavebeengraduallyrecognized .　Nowalthoughtheseparateseriouspollutionshavebeende creasedbyremovingandcontrollingthestrongpollutionsources ,theterritorialpollutionprobl…     

关于国际电工委员会2000年版热阻标准IEC60747-7中△VBE与IE关系的讨论

指出国际电工委员会标准IEC 747-7的热阻部分,关于晶体管电流电压温度关系的原理图和波形图是错误的,从理论上证明了该标准中的I-V-T曲线与实际情况相矛盾,这一矛盾也被实验所证实;同时给出了同一晶体管在两个不同温度下正确的I-V-T特性曲线和波形图,可以作为修正标准的参考样本.还提供了相应的计算和精确的实测结果.