平面七杆机构混合驱动器运动链分析和综合

使用传统RTNA(realtimenon adjustable)马达和RTA(realtimeadjustable)马达混合驱动平面两自由度七杆机构 ,达到既可以提供输出的柔性 ,又可以降低费用的目的。先就平面两自由度七杆机构进行型综合 ,得到平面两自由度七杆机构的四种运动链 ;然后逐一分析每一种运动链 ,得出适合于混合驱动器的一种运动链。为平面两自由度七杆机构混合驱动器的分析和设计打下基础。     

古田二级65MW水轮发电机双机兼容式频敏电刹车装置

新型频敏电刹车装置采用高能频敏电变阻器（ＧＢＰ）作为能耗设备,ＧＢＰ体积小,热容量大,能耗电阻具有频敏特性,它使机级在低速区产最优控制动力矩,频敏电刹车突出优点是：制动电流小,功率因数高,励磁容量低,理论和实践表明：新型频敏电刹车装置运行性能良好,是一项高新技术成果,应用前景看好,在兼容情况下,该装置性价比（Ｊ）为常规电制动（Ｊ）的（２－３）倍。     

提升风洞测力数据采集系统电磁兼容能力初步研究

随着风洞试验技术的不断进步,风洞现场的电磁设备越来越多,电磁干扰对风洞测力试验数据的准确性可靠性带来了挑战。研究风洞测力数据采集系统电磁兼容性问题是有效解决电磁干扰保障测力试验顺利进行的前提,是提高风洞试验精度、改善测量数据质量、提升试验能力的重要手段。文章以某主力风洞测力数据采集系统为研究对象,从电磁干扰途径和自身电磁敏感度两个方面对采集系统进行了电磁兼容分析,并结合分析结果通过采取合理有效的电磁兼容措施,提高了风洞测力数据采集系统抗电磁干扰能力,确保了测力试验数据质量的可靠性和稳定性。     

Scalable Substitutional Re-Doping and its Impact on the Optical and Electronic Properties of Tungsten Diselenide

Reliable, controlled doping of 2D transition metal dichalcogenides will enable the realization of next-generation electronic, logic-memory, and magnetic devices based on these materials. However, to date, accurate control over dopant concentration and scalability of the process remains a challenge. Here, a systematic study of scalable in situ doping of fully coalesced 2D WSe₂ films with Re atoms via metal–organic chemical vapor deposition is reported. Dopant concentrations are uniformly distributed over the substrate surface, with precisely controlled concentrations down to <0.001% Re achieved by tuning the precursor partial pressure. Moreover, the impact of doping on morphological, chemical, optical, and electronic properties of WSe₂ is elucidated with detailed experimental and theoretical examinations, confirming that the substitutional doping of Re at the W site leads to n-type behavior of WSe₂. Transport characteristics of fabricated back-gated field-effect-transistors are directly correlated to the dopant concentration, with degrading device performances for doping concentrations exceeding 1% of Re. The study demonstrates a viable approach to introducing true dopant-level impurities with high precision, which can be scaled up to batch production for applications beyond digital electronics.     

Eco‐Compatible Solvent‐Processed Organic Photovoltaic Cells with Over 16% Efficiency

Recent advances in nonfullerene acceptors (NFAs) have enabled the rapid increase in power conversion efficiencies (PCEs) of organic photovoltaic (OPV) cells. However, this progress is achieved using highly toxic solvents, which are not suitable for the scalable large‐area processing method, becoming one of the biggest factors hindering the mass production and commercial applications of OPVs. Therefore, it is of great importance to get good eco‐compatible processability when designing efficient OPV materials. Here, to achieve high efficiency and good processability of the NFAs in eco‐compatible solvents, the flexible alkyl chains of the highly efficient NFA BTP‐4F‐8 (also known as Y6) are modified and BTP‐4F‐12 is synthesized. Combining with the polymer donor PBDB‐TF, BTP‐4F‐12 shows the best PCE of 16.4%. Importantly, when the polymer donor PBDB‐TF is replaced by T1 with better solubility, various eco‐compatible solvents can be applied to fabricate OPV cells. Finally, over 14% efficiency is obtained with tetrahydrofuran (THF) as the processing solvent for 1.07 cm² OPV cells by the blade‐coating method. These results indicate that the simple modification of the side chain can be used to tune the processability of active layer materials and thus make it more applicable for the mass production with environmentally benign solvents.     

Liquid Metal Welding to Suppress Li Dendrite by Equalized Heat Distribution

It is important to understand the growth mechanism of Li dendrites for the protection of Li metal anodes. Herein, joule heat as another inducing mechanism for Li dendrites is proposed and demonstrated by experiments and theoretical simulations. A nonuniform interface structure can lead to disordered surface thermal distribution based on joule heat theory, which may induce chaotic nucleation and growth of dendrites. Based on this concept, a new strategy of liquid metal welding is explored to overcome such joule heat distribution issue. This strategy is universally compatible with other traditional protection routes such as solid electrode interphase films, charging protocols, and electrolytes. Multistrategy synergetic protection strategies result in remarkable performance.     

一种基于相容关系的聚类算法*

聚类分析是数据挖掘中一个重要研究内容。传统的聚类算法可划分为硬聚类和模糊聚类两大类,提出一种基于对象集上的相容关系的聚类算法,该算法通过极大相容簇来对数据对象集进行分类,使得同一对象可以属于不同的簇,而每个簇又有自己独有的成员对象,从而得到既不同于硬聚类也不同于模糊聚类的聚类效果。实验进一步表明了该算法的聚类的合理性。     

输油管道预热介质流速对预热时间的影响

输油管道在启输过程中,准确计算和预测管道周围土壤温度场以及管内介质温度随时间的变化规律,是确定合理投油时间和预热介质总量的关键.以热水为预热介质,通过不同流速条件下管道预热过程传热数值计算,对预热管道周围土壤温度场的分布及管道沿程温降进行了分析,得出了介质在不同流速下,输油管道预热情况,利于依此确定相应的输油工艺,达到...     

LED照明应用现状特征及驱动技术发展综述

LED以高光效、长寿命的优点获得了广泛关注,其节能的优点对绿色环保有积极的意义。LED驱动技术是当前的研究热点之一。在LED快速发展过程中,大量的机遇与挑战同时出现,对LED照明应用现状进行总结,以从中分析出LED照明应用的发展趋势显得非常必要。通过分析各种文献和应用,总结了LED照明应用现状的典型特征,即LED与其他光源并存、定制化与标准化并存、网络化控制兴起等特征。根据这些应用现状对LED驱动技术的进行了分析,提出了高适应性LED驱动技术发展的思路,以期对LED照明应用有所推动。     

孔隙率可控的多孔羟基磷灰石生物陶瓷的制备

采用凝胶成型法制备用作骨移植和药物传递的多孔羟基磷灰石(HA)生物医用陶瓷,通过改变工艺参数制得了孔隙率和孔径可控、内部连通的三维网状开孔结构的HA,对其孔隙率、孔径及生物相容性进行了分析.结果表明:通过改变循环浸渍次数可以控制调节孔隙率在45%～92%之间;通过改变母体模板和浆料涂层的厚度可以控制孔径;制得的HA具有良好的生物相容性,具有这种特点的孔洞结构有利于骨细胞的生长.