Polymers dynamics of the nonfluoro,nano-brush repelling agent with self-stratifying property in water-based coatings

While perfluoroalkyl acids (PFAAs), also known as C8s, are used extensively in textile repellent coatings, concerns have arisen for their carcinogenicity and hazardous effects on the environment. In this study, a novel water-based, nonfluoro, and nanobrush textile repelling agent was prepared by conventional sol–gel chemistry using amorphous fumed silica and n-octyltriethoxysilane as the starting materials. Minimal interaction between the designed repelling agent and marketed water-based resins was confirmed using linear viscosity region (LVR) analysis and asymmetric-flow field-flow fractionation (AF4), suggesting the self-stratification potential of the repelling agent. More specifically, the repelling agent exhibited excellent compatibility and self-stratifying ability with a force-emulsified acrylic-based resin, affording a water contact angle of 104.3° when incorporated at 7% solid content. Performance tests carried out on thermoplastic polyurethane (TPU) revealed excellent adhesion (100/100) of a final formulation, and a significant increase in water contact angle from 80.1° to 103.8° after treatment. In addition, the fouling area after the removal of a submerged sample from a mixture of slurry, polymer, and oil decreased from 48 to 1% when the repelling agent was added. Moreover, the sludge-fouling property remained unchanged after 1000 cycles of abrasion. These findings demonstrate the potential of the described nonfluoro, nanobrush repelling agent as an environmentally safe alternative for use with commercial resins, in turn realizing a fully water-based hydrophobic coating. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48003.     

数字化蓄热式钢包烘烤器及自动控制系统

蓄热式燃烧技术和脉冲燃烧技术是新型的节能环保燃烧技术。数字化蓄热式钢包烘烤器控制系统利用数字化脉冲控制把这两项技术结合在一起。这大大降低了能耗，减少环境污染。本文针对数字化蓄热式钢包烘烤器，提出升温阶段采用自寻优算法，不断调整换向时间，并能记忆最优参数，保证经过几次烘烤后系统整体最优；保温阶段即采用脉冲控制的方法。     

基于射频技术的无刷同步电机励磁电流的检测

无刷同步电机的励磁系统对励磁电流的测量是制约该励磁方式发展的一大障碍。设计了一个射频系统可以用来解决同步电机的励磁电流的测量问题。该系统可以方便地检测到同步电机励磁机的整流二极管的工作状态并且可以动态地显示励磁电流，极大地方便了运行人员做出判断，而且结构简单、方便实用。     

Growth Defects in Langasite Crystals Observed with White Beam Synchrotron Radiation Topography

Langasite single crystal was grown by the Czochralski method and its perfection was assessed by white beam synchrotron radiation topography. It is found that the growth core and the growth striations are the primary growth defects and they show strong X-ray kinematical contrast in the topographs. Another typical defect in LGS crystal is dislocation. The formation mechanisms of these growth defects in LGS crystals were discussed.     

变频器调速装置节能浅析

1概述 近十多年来,随着电力电子技术、微电子技术及现代控制理论的发展,变频调速技术已经广泛地用于交流电动机的速度控制,其最主要的特点是具有高效率的驱动性能及良好的控制特性.它是一种高新技术电力节能装置,它通过改变（降低）电源工作频率,来降低动力设备（电机）的转速,减少设备的输出功率,达到输出功率与工作负荷的最佳匹配,实现节能目的,有效地提高了经济效益和产品质量.几乎可以说,有电动机的地方就有变频器,在一切需要进行速度控制的场合,变频器以其操作方便、体积小、控制性能高而获得广泛应用.     

HFC电缆分配系统的建设与思考

结合沧州市网络的实际情况，主要分析HFC电缆分配系统双向传输改造的建设标准和实施方案。     

低插损窄带型10.7MHz压电陶瓷滤波器的研制

介绍了低插损窄带型10.7 MHz压电陶瓷滤波器的一种设计制作方法。结合压电陶瓷能陷模理论,通过对滤波器分割电极设计和制造工艺控制技术的研究,强调了工艺控制的重要性。产品达到日本村田同类产品水平,对国产化窄带型10.7 MHz压电陶瓷滤波器的研发和生产具有十分重要的意义。认为选用高Qm值压电陶瓷材料、分割电极和耦合电容的设计、焊接和点蜡工艺的控制等是研制低插损窄带型10.7 MHz压电陶瓷滤波器的重点。     

High-performance and power-efficient CMOS comparators

Several design techniques for high-performance and power-efficient CMOS comparators are proposed. First, the comparator is based on the priority-encoding (PE) algorithm, and the dynamic circuit technique developed specifically for the priority encoder can be applied. Second, the PE function and the subsequent logic functions are merged and efficiently realized in the multiple output domino logic (MODL) to result in a shortened logic depth. The circuit in MODL CMOS is also compact and power efficient because few transistors are needed. Third, the multilevel look-ahead technique is used to shorten the path of priority-token propagation. Finally, the circuit is realized with a latch-based two-stage pipelined structure, and the comparison function is partitioned into two parts, with each part executed in each half of the clock cycle in a delay-balanced manner. Post-layout simulation results show that a 64-b comparator designed with the proposed techniques in a 3-V 0.6-/spl mu/m CMOS technology is 16% faster, 50% smaller, and 79% more power efficient as compared with the all-n-transistor comparator, which is the fastest among the conventional comparators. Measurement results of the test chip conform with simulation results and prove the feasibility of the proposed techniques.     

数字化正弦平方脉冲信号

依据正弦平方脉冲的数学方程及其频谱分布，分别导出了与理想和标称视频带宽相对应的正弦平方脉冲的数学表达式及其编程生成方法。实验表明，此法不仅精确，而且便于修改参数，并可直接读人数字电视系统，来测定视频线性响应。