双活塞式压力计准确度等级的确定

双活塞式压力计基于不同结构可分为双活塞式压力真空计和双量程活塞式压力计两种。针对后者的结构特点,分析两套活塞系统共用一套砝码的问题,根据活塞的参数以及专用砝码质量计算出标称值下的实际压力值。本研究根据不同压力量程段来划分活塞式压力计的准确度等级,实现活塞式压力计的溯源性校准,以保证压力量传中的准确性和一致性。     

All‐Organic Dual Spin Valves with Well‐Resolved Four Resistive‐States

The formation of all‐organic dual spin valves (DSVs) with three organic spin‐selective layers, that is, spin‐injection, spin‐detection, and an additional spin‐filtering layer at the intermediate, is reported. As spin‐selective layers, manganese‐ and cobalt phthalocyanines, which are well‐known single‐molecule magnets, are used in their immobilized forms, so that all‐organic DSVs can be prefabricated for characterization. The three spin‐selective layers have provided four configurations with at most two spin‐flip interfaces enforcing spin‐flipping at the two nonmagnetic organic spacer layers, for which copper phthalocyanine is used. Since a couple of the four configurations have exhibited similar resistivities, the degeneracy in the resistive‐states is broken through asymmetric spin‐injection and spin‐detection layers and also through asymmetric thickness of the nonmagnetic spacer layers. When both the spin‐flip interfaces are made operative independently, a 2‐bit logic with four distinct resistive states can be achieved.     

对称循环矩阵的一些结果

讨论了对称循环矩阵的性质,并研究了任意矩阵在对称循环矩阵中的逼近问题。     

舒曼钢琴音乐的双重性格特征

德国作曲家罗伯特·舒曼是十九世纪上半叶欧洲音乐文化史上最突出的人物之一。在他的钢琴音乐创作中,深刻地反映出浪漫主义音乐的特点。舒曼设计了一个想象中的“大卫同盟”,其中有两名核心盟员,一个叫弗洛列斯坦,另一个叫埃塞比乌斯。前者性格热情奔放,锋芒毕露;后者则文雅娴静,富于幻想,实际上这就是舒曼本人性格中的两个侧面。这种双重性格特征在舒曼的钢琴音乐中得到充分展示,并成为舒曼钢琴音乐的艺术特征之一。     

一次风反切系统的数值模拟和多相流动特性分析

四角切圆燃烧锅炉,存在着稳燃和结渣的矛盾,一次风微反切技术已在多台锅炉上得到应用,较好地解决了这对矛盾并能在一定程度上降低ＮＯｘ的排放量。本文把湍流理论和多相流动理论应用于炉内空气动力场的计算机数值模拟,用投影法编制的计算软件对６００ＭＷ锅炉炉内流动进行了计算,得出了一次风反切系统中炉内速度场、实际切圆、颗粒运动轨迹等结果,与冷炉和冷模试验基本吻合,对一次风反切系统的设计和调试具有参考价值。     

Quasi-physical global optimization method for solving the equal circle packing problem

The equal circle packing problem is a well-known challenge in geometry.It is also a natural,clear and fair test system for global optimization.This paper presents a quasi-physical global optimization algorithm for solving the equal circle packing problem.The algorithm simulates two kinds of movements of N elastic disks: smooth movement driven by elastic pressures and violent movement driven by strong repulsive forces and attractive forces.The smooth movement makes the disks reach a locally optimal configura...     

变频器双向双速功能的实现

介绍在Logix5000编程软件中如何添加一台新的PowerFlex70变频器,以及如何通过程序让其实现双向双速功能。     

IPv4向IPv6过渡阶段中校园网的升级研究

随着快速发展的网络,IPv4协议在应用显露了许多问题。分析IPv6协议的特点和优势,采用IPv4到IPv6过渡的基本技术,以上海海洋大学校园网建设为实际背景,探讨了以IPv4为主的校园网升级到以IPv6为主的校园网在各个阶段的校园网的架构方案,实现校园网的升级。     

A dual‐polarized cylindrical conformal array antenna suitable for unmanned aerial vehicles

A dual‐polarized X‐band conformal array antenna is presented for unmanned aerial vehicles with polarimetric radars/sensors. Starting from the planar structure, the array antenna consisted of sixteen 2 × 2 subarrays is conformal to the cylinders with various curvature radii to fit the payload box of the airborne vehicle. The return losses are almost constant even if the curvature radius changes. Measured radiation patterns are compared with various curvatures at the same frequencies. The array can be easily placed on the aircraft payload or fuselage due to its ultra thin thickness, ultra lightweight, and conformal structure, which has potential airborne applications in polarimetric radar surveillance, remote sensing, and wireless communications. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Analysis of frequency‐selective impedance loading of transmission lines for dual‐band couplers

This article proposes an analytical design methodology for dual‐band hybrid couplers and baluns structures for any arbitrary frequency ratio using a stub‐loaded transmission line. An analysis of changing the impedance behavior of the stub, is carried out for the two bands of operation, which along with a dispersive analysis, emphasizes certain conditions where the existing methodology is not applicable. In addition, an extra degree of freedom has been included to increase the solutions for a given frequency ratio, thus providing greater flexibility and feasibility of the proposed structure. The design methodology is experimentally validated with the design and fabrication of dual‐band branch‐line and rat‐race couplers for various commercial frequency bands. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2011.