电机车变压器油箱制造工艺简述

介绍了ＪＱＦＰ－７７００／２５型电机车变压器油箱的基本结构及针对其结构特点制定的工艺程序和制造方法。     

夹钳式承载架结构及应用介绍

介绍了一种在特大型变压器运输中采用的夹钳车承栽架的基本结构,分析了承栽架应具有的各个自由度,并对夹钳式承栽架的不同方案进行了比较和分析。     

双机架可逆冷轧机张力控制系统的研究

文章针对双机架可逆冷轧机的特点和轧制工艺要求,采用间接张力与直接张力复合控制法以实现卷取恒张力控制;提出了机架间张力控制系统的组成,描述了两种调张法的控制原理与实现方法.     

现场总线Profibus-DP主从站数据交换探讨

介绍了Profibus-DP网络的基本特性、结构、主从通信原理。然后结合奥地利贝加莱公司(B&R公司)现场总线模块对主从站Profibus-DP数据交换的实现方法作了详细地讨论。     

基于两相正交开关霍尔传感器的混合型转子位置预估方案的FPGA实现

提出了一种利用两相正交的锁定型开关霍尔传感元件对正弦波永磁同步电动机转子位置进行预估计的新型数字电路设计方案,并进行了误差分析,最后在可编程逻辑器件FPGA上完成了布局布线和时序验证.仿真和实验结果表明稳态时能够获得比较高的位置精度,而且性价比比较合理,可以与其他功能模块或IP芯核相结合应用在低成本的简易正弦驱动场合.     

Growth and optical properties of Er,Yb:YAl3(BO3)4 crystal

Single crystal of erbium, ytterbium-codoped yttrium aluminum tetraborate Er,Yb:YAl₃(BO₃)₄(Er,Yb:YAB) has been grown by the flux method. The absorption spectrum in the visible and NIR regions of Er,Yb:YAl₃(BO₃)₄ crystal are measured at room temperature and fluorescence spectrum of Er,Yb:YAl₃(BO₃)₄ crystal are also measured at room temperature, excited by 976 nm laser. Not only the strong NIR emission peaks located at 1548 nm was observed, but also the visible up-conversion luminescence has been found. The specific heat of the Er/Yb:YAB crystal at room temperature is 0.81 J/g °C.     

A hybrid rough-cut process planning for quality

This paper proposes a hybrid approach to develop a rough-cut process planning for quality. The approach aims to determine key process alternatives with an adequate process capability by systematic quality planning and assessment methods during the initial planning stage of the product development cycle. It consists of four steps: (1) identification of quality characteristics (2) planning of the process quality by combining quality function deployment (QFD) with the process failure mode and effect analysis (FMEA) (3) a selection of process alternatives, and (4) an assessment of process quality through a quality measure index, called the composite process capability (CCP). The process alternatives with an adequate CCP selected during the early design stage can then be not only used as the guidelines for detailed process planning but also as feedback for the product design and other functions for design evaluation and improvement. This approach is helpful to reduce or even eliminate the iterations of modification of process plans. A prototype system called the rough-cut process planning for quality (RPPFQ) has been developed for validation. A case study concerned with a satellite frame part is presented to illustrate the approach and prototype system in this paper.     

Symmetry in electron diffractions from helical structures

In this work, we elucidate the regular rule of the symmetry in electron diffraction patterns from helical structures. It is affected by the value of the dominating Bessel function orders for the layer lines and relative orientation of the samples with respect to the electron beam. For Single-Walled Carbon nanotubes (SWCNTs), we use analytic analysis and computer simulations to demonstrate that the 2mm symmetry of the electron diffraction may break down not only from an achiral SWCNT, but also from a chiral SWCNT. Also, the simulation work for B-DNA is presented to corroborate the theoretical analysis.