对氯甲苯合成方法的研究及进展

对现有合成对氯甲苯的工艺方法进行了综述，比较了国内外业已提出的多种氯化工艺，并作出评价，提出改进合成对氯苯的工艺的方向。     

Synthesis of Aluminum Nitride Nanocrystalline

Nanocrystalline aluminum nitride (whisker and particle) has been synthesized by heating the mixed aluminum+aluminum nitride ultrafine powders (UFPs) produced by nitrogen plasmamolten aluminum reaction, under N2 atmosphere at lower temperature. Some bamboo-like nano- whiskers of aluminum nitride were observed in TEM, the possible formation mechanism of the whiskers was also disucssed.     

高速搅拌对淀粉／聚乙烯醇共混物薄膜性能的影响

通过高速搅拌，将淀粉与聚乙烯醇进行溶液共混，制备了淀粉／ＰＶＡ共混薄膜。测定了高速搅拌前后共混薄膜的力学性能。透明性，耐水性及生物降解性。结果表明，高速搅拌改善了淀粉／ＰＶＡ薄膜的力学性能，透明性与耐水性，并可提高共混膜的全用稳定性。     

冰箱压缩机使用电工钢的状况及质量改进意见

调研了我国冰箱压缩机产销现状，指出了所使用的电工钢牌号、质量和数量，给出了武钢和日本电工钢研制状况，提出了冰箱压缩机用电工钢质量改进意见。     

数控车床精密进给传动的预加载装置

一种高效预加载装置,利用碟形弹簧受压变形储备的能量压缩传动轴端的螺杆、推杆、转动钢球组成的预加载系统,迫使传动轴上的斜齿轮在轴上发生轴向移动,来达到使相啮合的斜齿轮上的另一轴产生相对转动,从而消除传动链间隙,达到补偿磨损及动态误差.     

Electrocatalysis induced by surface-modification with Pd through sol–gel method for Ti33V20Cr47 alloy

A body-centered-cubic (bcc) phase Ti₃₃V₂₀Cr₄₇ alloy surface-modified with Pd particles was prepared through sol–gel method. The composite showed significantly improved electrochemical hydrogen release capacities, reaching 225 mAh g⁻¹ at a discharge current of 60 mA g⁻¹ at 293 K in the second cycle. Such a large capacity could be attributed to the contribution of catalysis of Pd particles, which induced the Ti₃₃V₂₀Cr₄₇ alloy to release hydrogen more easily. These results provide a new approach to wide applications of Ti–V-based bcc phase alloys in high-energy batteries.     

新能源发电系统参与频率和电压响应的模型预测控制策略

随着风电和光伏的快速发展,大规模新能源接入可危及电网的安全稳定运行,新能源发电应参与调频、调压,且提供足够的备用容量.为此,基于模型预测控制方法,本文提出新能源发电系统参与调频和调压的控制策略.该策略分为两层,在考虑风电场、光伏电站和电池储能系统各自的约束条件的前提下:上层控制器通过求解约束优化问题,计算各新能源发电系...     

纤维表面绝缘处理对含碳纤维非织造布雷达波吸收性能的影响

利用碳纤维和普通纺织纤维混纺,可以制作具有良好雷达波吸收性能的非织造布。探讨了对非织造布中的纤维进行绝缘处理对非织造布雷达波吸收性能的影响规律。实验中使用羊毛纤维、沥青基碳纤维和双组分热熔粘合纤维,通过粗梳毛纺成网工艺和热风法工艺制作了对雷达波有一定吸收能力的非织造布;采用氨基改性聚硅氧烷对非织造布中的纤维进行了表面绝缘处理。利用专用的雷达吸波材料反射率测试装置测试了不同碳纤维含量非织造布的雷达波反射率,并在8~18GHz频率范围内比较了纤维表面处理对非织造布雷达波吸收性能的影响。结果表明,纤维表面绝缘处理会在一定程度上提高非织造布的雷达波吸收能力,但是绝缘处理造成的影响随着非织造布中碳纤维含量的减少而逐渐降低并趋于消失。     

Homotopy analysis of unsteady heat transfer started impulsively from rest along a symmetric wedge

In this paper, the unsteady heat transfer over an impulsively started wedge is investigated. The mixed convection, namely, the thermal boundary-layer growth is caused by the sudden increase of the surface temperature as it is set into motion. The analytic approximations with high accuracy are given using the Homotopy–Padé technique, which agree well with the numerical results using an implicit finite-difference method known as Keller–Box method. It is found that the Homotopy–Padé approximations have no relation to the auxiliary parameters ?_f and ?_g, which play important roles in the homotopy analysis method.