德国萨其宾公司考察记实

介绍了作者赴欧洲考察萨其宾公司的概况、该公司的生产工艺及重要操作程序;介绍了萨其宾公司的主要产品牌号及性能;着重叙述了萨其宾公司三废治理及所取得的环境效益,发表了四个方面的观后感。     

离子束刻蚀正交位相型Ronchi光栅研究

本文报道了采用紫外光刻和离子束刻蚀方法制作正交位相互Ｒｏｎｃｈｉ的工艺技术,并讨伐春衍射效率,给出公式及实验结果。     

Templated spherical coassembly strategy to fabricate MoS2/C hollow spheres with physical/chemical polysulfides trapping for lithium-sulfur batteries

Rational design of advanced polar hosts with high sulfur loading,facilitated ionic/electronic transport and effectively suppressed shuttling effect has great po...     

砂型铸造D型石墨铸铁的研究

研究了冷却速度和含钛量对砂型铸件金相组织的影响,通过控制含钛量和壁厚获得了Ｄ型石墨铸铁     

服务于科研和管理的计算机局域网络

本文论述了一种基于客户机／服务器（通常用Ｃ／Ｓ表示）结构,可用于科研和管理的局域网络系统的设计、组织,实现办法和下一步的发展方向。     

一种稳健的窄带反馈型主动噪声控制系统

传统窄带反馈型主动噪声控制系统采用并型自适应滤波器结构,用于合成参考信号时,仍存在参考信号合成质量较差、 滤波器权值的初值设置难度高、应对非平稳窄带噪声的能力不足等问题。 为解决以上问题,通过引入高效的串并型自适应滤波 器结构来合成参考信号,提出新型的窄带反馈型主动噪声控制系统,改善参考信号合成质量,进而提升系统的整体降噪性能。 新型系统不仅有效解决了传统系统存在的参考信号合成质量较差的问题,还降低了滤波器权值的初值设置复杂度,同时还提升 了系统应对非平稳窄带噪声的能力。 实验结果表明,新型系统较传统系统的前后两部分的降噪量分别提升了 7. 89 和 9. 18 dB。 仿真和实验结果共同验证了提出的系统较传统系统具有更强的稳健性和降噪性能。     

Performance of multibeam CDMA-based LEO satellite systems with imperfect power control

Bit error probability of a DS-CDMA multispot beam LEO system with imperfect power control is analysed in this paper. The power control error is assumed to be a lognormal random variable. The channel is a combination of Rician and Suzuki distributions. For more realistic applications the multiple-access interference due to all users seen by the serving satellite for the user of interest is taken into account. This differs from other reported work in which only part of all possible interference was considered. The numerical results with different numbers of interferers show that the interference coming from the users located outside the footprint but seen by the reference satellite has a non-trivial effect on the system capacity. However, the multiple-access interference can be reduced by increasing the elevation restraint of each satellite footprint. Estimates on this reduction are given. It is also shown that the performance of shadowed users is highly sensitive to the power control error. © 1998 John Wiley & Sons, Ltd.     

基于改进双树RRT*算法的冗余机械臂末端路径规划

针对冗余机械臂的冗余特性与相关RRT*算法在规划机械臂末端路径的应用中存在的搜索效率较低、收敛性不稳定以及没有充分考虑到机械臂末端几何构型与自身运动特性对路径规划影响的问题,提出一种改进策略。首先,引入一种基于根尾节点连线夹角的采样点选择方式,并设置目标逼近区域。根据连续采样成功次数动态选择改进采样与随机采样。接着,将双树扩展策略与上述方法相结合。最后,将初始可行路径进行二次重连得到最终的优化路径。通过验证,改进双树RRT*方法能够有效地提升搜索效率、收敛性以及路径的优越性。虚拟碰撞体与胶囊碰撞体的引入也能较好地应对机械臂末端结构与运动特性带来的影响。使用Mujoco物理仿真引擎进行机械臂运动验证,证明该策略可以为冗余机械臂末端规划出一条较优的可行路径。     

Proton Turnover Dominated Cascade Route for CO2 Photoreduction

Photoreduction carbon dioxide (CO₂) and water (H₂O) into valuable chemicals is a huge potential to mitigate immoderate CO₂ emissions and energy crisis. To date, tremendous attention is concentrated on the improvement of independent CO₂ reduction or H₂O oxidation behaviors. However, the simultaneous control of efficient electron and hole utilization is still a huge challenge due to the complex cascade redox reactions. Here, a proton turnover exists in the whole CO₂ photoreduction process is discovered, which is defined as the pivot to concatenate the hole and electron behaviors. As a demonstration of the concept, the efficient activated hydrogen (*H) production centers of copper (Cu) and rapid hydrogenation centers of nickel (Ni) are coupled by an alloying strategy, and the proton turnover behaviors could be directly determined by adjustment of the molar ratios of Cu_xNi_y. Moreover, Cu₃Ni₁–TiO₂ exhibits the highest electron selectivity of 93.7% for methane (CH₄) production with a rate of 175.9 µmol g⁻¹ h⁻¹, while Cu₁Ni₅–TiO₂ reaches up to the highest carbon monoxide (CO) electron selectivity and generation rate at 84.4% and 164.6 µmol g⁻¹ h⁻¹, respectively. Consequently, the experimental and theoretical analysis all clarify the predominate proton turnover effect during the overall CO₂ photoreduction process, which directly determines the categories and generated efficiency of C-based products by regulating variable reaction pathways. Therefore, the revelation of the proton turnover pivot could broaden the new sights by bidirectional optimization of dynamics during the overall CO₂ photoreduction system, which favors the efficient, selective, and stable photocatalytic CO₂ reduction with H₂O.