Line balancing in a just-in-time production environment: balancing multiple U-lines

The introduction of multiple, independent production lines has helped many firms to increase their production flexibility, provide for redundancy when equipment breaks down, reduce idle time and labor costs, and achieve many other benefits. This paper introduces and formalizes the multiple U-line balancing problem. Optimal solution methodologies are provided for Type I (minimize the number of stations for a given cycle time), Type II (minimize the cycle time for a given number of stations), and cost-minimization line-balancing problems. A branch-and-bound algorithm is also developed for the situation in which equipment requirements are dependent on the line configuration and the task assignment to stations. Computational results indicate that the greatest benefit of exploiting multiple lines occurs for smaller cycle-time problems that require higher output.     

市县HFC系统如何选择和使用光端机

对有线电视工程设计中如何选用优质设备、提高网络质量等问题进行探讨     

Extremes of random fields over arbitrary domains with application to concrete rupture stresses

To find the exact probability distribution of the global maximum or minimum of a random field within a bounded domain is a pending problem even for Gaussian fields. Except for very special examples of fields, recourse must be taken to approximate reasoning or asymptotic considerations to be judged with respect to accuracy by simulations. In this paper, the problem is addressed through a functional equation that leads to the definition of a class of distribution functions that depend solely on process or field characteristics and domain quantities that can be calculated explicitly. This distribution function class is studied for Gaussian processes in earlier works by the author and it has been obtained explicitly for Gaussian fields on rectangular domains in the plane. Simulation studies show that rather good predictions are obtained for sufficiently smooth wide band Gaussian processes and fields. In this paper, the distribution function is obtained in general for Gaussian fields over arbitrary bounded domains with piecewise continuous and differentiable boundaries, and as in earlier works the distribution function is tested against empirical distribution functions obtained by simulation of sample functions of a smooth approximately Gaussian field, herein called a broken line Hino field. For completeness this particular field type is defined in appendix a and appendix b. The paper concludes with a statistical application on data for plain concrete tensile strength.     

核孔膜生产线膜微孔制备工艺实验研究

本文介绍核孔膜生产线,重点描述了膜微孔制备工艺的实验研究。对于PC和PES膜,已得到32种工况下的扩孔公式,其形式为D=A+Bt,其中D——孔径,t——扩孔时间,A,B为特定工艺参数下的常数值.通过实验。得到了膜孔密度N与300~#核反应堆功率P、热柱辐照位置L的经验公式,即N=6.97×10~5×10~3×101~(1.18L).在本生产线上可生产最大幅面为3 140mm×240mm,孔径为0.04～10 μm的多系列多规格的核孔膜产品。     

冷轧厂酸洗机组3号横剪大流量中高压液压系统设计方案探讨

在宝钢２０３０ｍｍ冷轧厂酸洗机组中，为了满足厚规格ＩＦ钢的生产，拟将原有的气动式剪切机改成液压式剪切机。为此，设计了一套中高压大流量的液压系统以满足３号横剪大剪切力（最高达７００ｋＮ）和快速剪切（３秒／次）的需要。由于采用了蓄能器增速回路和二通插装阀控制技术，使该液压系统较传统的剪切机液压系统具有响应速度快、体积小、重量轻、发热少和降低电机能耗等优点。     

传输线衰减常数与柱形谐振器Q值的关系

文中严格地讨论了任意截面形状，任意模式的柱形谐振腔Ｑ值与构成该谐振器的传输线衰减常数间的关系，给出了更一般的公式，推广了Ｄａｖｉｄｓｏｎ和Ｓｉｍ－ｍｏｎｄｓ＾［１］、Ｂａｒｌｏｗ和Ｃｕｌｌｅｎ＾［２］以及Ｙｅｈ和Ｓｈｉｍａｂｕｋｕｒｏ＾［３，４］的结果。     

用于X光激光实验的反射式线聚焦光学系统的设计和分析

基于三维光线追迹的象差计算,对卢瑟福实验室用离轴球面反射线聚焦系统作了分析。然后,首次提出了用于X光激光实验的两类新的反射式线聚焦构型,即反射式光楔列阵和光锥列阵系统,并作了计算。最后,对所得结果作了比较和讨论。     

黄土塬区天然气地震技术和综合解释

黄土塬区复杂的地表条件难以获得可供解释的物探资料,本文给出了勘探天然气的地震技术,在野外弯线地震数据采集中,冲沟区运用了弯线高分辨率技术;塬上区采用非纵测线和地震测深观测系统,大药量、深井和强化组合法的接收条件。初步解决了弯线地震资料处理中二维滤波、静校正、速度分析等技术难题。摸索出一套以地震为骨架,构造解释与岩性解释相结合,重力-电法-地震联合解释落实古生界天然气构造圈闭的综合物探解释技术,并以实例展示方法的有效性。     

极尖断面为折线的四极透镜磁性能研究

对传统双曲线极尖的四极透镜进行了磁性能分析。在此基础上，提出了极尖断面为折线的四极透镜结构。磁场的数值分析以及测量结果表明：该结构产生的场梯度均匀，且具有磁场集中、磁场梯度高、便于加工和安装的对称性控制等优点。该结构的四极透镜已用于ＣＹＣＩＡＥ－３０回旋加速器和ＨＩ－１３串列加速器束流输运线之中     

Effects of calcination temperature on phase and microstructure evolution of BaTi4O9 powders

Calcining of the mixture of BaCO₃ and TiO₂ with a ratio 1:4 at different temperatures was carried out to synthesize BaTi₄O₉ powders. Phase evolution of the samples was studied using the differential thermal analysis (DTA) and X-ray diffractometry (XRD). Both techniques confirmed that the formation of BaTi₄O₉ started around 1000 °C. The XRD peaks showed that BaTi₄O₉ was most pronounced at 1250 °C. X-ray line broadening methods were employed to study the variation of particle size and microstrain of the BaTi₄O₉ powders. The Voigt function in a single line and the pseudo-Voigt function in the variance methods were used in our case. We found that both functions resulted in the same trends, i.e., the particle size increased with the temperature with the biggest size of 180 and 160 nm, whilst the microstrain yielded the opposite trend with the lowest values of 6.2 × 10^–3 and 1.1 × 10^–3. The scanning electron microscopy (SEM) study revealed the size of the large particles formed, due to agglomeration, to be about 0.5–1.9 μm. Furthermore, it was shown that irregular shapes of BaTi₄O₉ powders necked to each other appeared at 1000 °C and grew into ellipse and rod shapes at 1250 °C. Electronic Publication