光缆传输设备工程配套设施安装设计探讨

简要阐述了光缆传输系统工程设计界面的划分;根据中国移动集团提倡的标准化建设管理思路,从光缆传输设备工程特点和实践工作经验出发,对相关配套设施的安装设计进行了探讨,并提出了初步实用方案     

Highly Power‐Efficient Rack‐Level DC Power Architecture Combined with Node‐Level DC UPS

This letter presents a highly efficient rack‐level DC power architecture combined with a node‐level DC uninterruptible power supply (UPS). The proposed system can provide almost the equivalent power efficiency of a high‐voltage DC data center without any change in the existing power infrastructure. The node‐level DC UPS combined with a power distribution board provides high power efficiency as well as lower UPS installation costs. Implemented on a rack, the entire power system can be monitored through a network.     

单纤维平均梳理力的研究

建立了单纤维平均梳理力的计算公式,通过工艺实验揭示了不同梳理工艺条件下,单纤维平均梳理力对生条中棉结和短绒的影响,并根据单纤维平均梳理力推算了锡林齿条前角其余角的最小值.     

大齿轮齿形在机测量原理与技术

在机测量大齿轮齿形误差具有广阔的发展前景。本文分析了大齿轮齿形误差在机测量的关键问题，提出了运用齿条刃边测头与被测齿轮横截面进行啮合的测量方法，既能测量齿轮的端截面齿形误差，又使仪器结构紧凑。在分析影响大齿轮形在机测量的诸误差因素的基础上，得出了在仪器的制造及安装精度要求不很高的情况下仍能实现齿轮的高精度测量的可喜结论。     

Numerical analysis of jacking operations for a self-elevated jack-up unit

Localized failure and collapse of a jack-up unit may take place during installation on site, especially under severe sea state conditions. To minimize the loss, structural behavior is predicted before construction. When the hull of a unit is elevated from sea water level, the structure system varies with time. This means that normal structural analysis is difficult to satisfy the relevant requirements. To capture the system status at different times, an innovative method is proposed and incorporated into Finite Element Analysis (FEA). With a full model of a jack-up unit having been built and with the techniques developed, behavior such as Rack phase difference (RPD), vertical reaction forces of the pinions and footing reactions, etc., under different loads and boundary conditions can be determined by FEA in the time domain. These valuable data would be helpful in re-designing the unit, and also provide guidance for site installation. To determine the general characteristics of a jack-up unit, casestudies on a practical design have been done, with some important findings concluded.     

汽车变速比齿轮齿条式转向器的啮合原理(Ⅰ)

对汽车变速比齿轮齿条式转向器的啮合原理进行了系统研究。首先讨论了转向器采用变速比的必要性及速比选择原则,在已知齿轮齿面（渐开线螺旋面）和给定速比规律下,应用共轭曲面原理给出了齿条齿面方程,并发现：瞬时接触线为直线;齿条齿面为可展面;该可展面的腰线为定倾曲线等,最后讨论了端截面齿形。     

Influence of the elimination and addition of seeds on the colour,phenolic composition and astringency of red wine

Several winemaking techniques have been developed to eliminate seeds to prevent the release of high amounts of very astringent proanthocyanidins, especially when the grapes are unripe. However, there is no scientific information on the effects of this practice. The aim of this paper is to study how the elimination and addition of seeds influence the colour, phenolic composition and astringency of red wine. The elimination of around 80% of the seeds led to a significant decrease of colour intensity and anthocyanin concentration. The addition of seeds originated wines with a greater concentration of total anthocyanin, but did not significantly affect the wine colour. These wines also presented significantly higher levels of proanthocyanidins, a greater proportion of epicatechin-3-gallate, a lower mean degree of polymerization, and, in particular, a drastic increase in astringency. Wines obtained with the elimination of seeds, on the other hand, had exactly the opposite characteristics.     

Adaptive preloading for rack-and-pinion drive systems

In the field of machine tools, rack-and-pinion drive systems are one of the commonly used feed drive systems. In order to achieve the high accuracy specifications of modern production facilities, these drives are electrically preloaded to reduce backlash in the drive train. In most cases, the preload is fixed, even though the method of electrical preloading allows adjustment during operation.This paper describes a novel approach – called adaptive preloading – to adjust preload during operation. The objective is to increase the drive system’s energy efficiency by continuously adapting the preload, which is minimally required for maintaining the drive system’s accuracy.     

梁-柱节点半刚性力学性能的有限元分析与验证

货架梁-柱节点是横梁式货架设计中的关键部件,是联系托盘横梁和立柱的枢纽,其安全性直接影响货架的整体工作性能。梁-柱节点本质上具有半刚性的力学特征,一般需要通过大量试验确定其具体数值。在研究国外文献基础上建立了合适的梁-柱节点有限元模型,运用合理的节点处理方法,通过非线性仿真分析绘制了M-θ曲线,使其与已有试验数据进行了比对。结果显示,该曲线与试验曲线吻合良好,从而为货架整体结构优化设计提供了新的依据。     

大型齿轮齿形误差信号的采集与分析软件

简单介绍了大型齿轮在机测量仪的专用测量软件中关于齿形误差信号的采集和分析软件的结构和功能,并举例说明了软件计算精度可靠,证明了在机测量原理正确,误差分析结果对工艺调整具有重要指导意义。