Optimization framework for process scheduling of operation-dependent automobile assembly lines

Productivity, cost, and completion time are regarded as performance measures for assembly production management. The traditional decomposition of Assembly Line Balancing (ALB) and Car sequencing (CS) does not work well, especially when operations belonging to different car types are sequence-dependent and time overlap between two successive workstations is allowed. In this paper, we first use a motivating industrial-scale example to demonstrate that the traditional ALB/CS decomposition method could not satisfy modern continuous production demands in a flexible assembly line. Then, we present a new optimization objective to scale the Operation Process Precision (OPP) that relates to the operation assignment sequence. Lastly, we propose a two-stage hierarchical optimization framework to solve the CS, the operation allocation, and the operation sequence problems. This framework consists of (a) a new Mixed Integer Linear Programming (MILP) model for sequencing automobiles and allocating their operations to each station, and (b) a novel MILP model for determining the operation sequence and timing of each car type. The motivating industrial case is revisited with the proposed framework to illustrate its validity and efficiency.     

Simultaneous determination of eight bioactive constituents of Zhi‐Zi‐Hou‐Po decoction in rat plasma by ultra high performance liquid chromatography with tandem mass spectrometry and its application to a pharmacokinetic study

Zhi‐Zi‐Hou‐Po Decoction, consisting of Gardenia jasminoides Ellis, Magnolia officinalis Rehd. et Wils., and Citrus aurantium L, is a classical Traditional Chinese Medicine formula for the treatment of depression. In order to make good and rational use of this formula in the future, a sensitive, selective, and reliable ultra high performance liquid chromatography with tandem mass spectrometry method was developed for simultaneous determination of two iridoid glycosides (geniposide and genipin gentiobioside), two lignans (honokiol and magnolol), four flavonoid glycosides (isonaringin, naringin, hesperidin, and neohesperidin), the major bioactive constituents of Zhi‐Zi‐Hou‐Po Decoction, in rat plasma using paeoniflorin as internal standard. Plasma samples were pretreated by a simple protein precipitation with acetonitrile. Chromatographic separation was performed on a shim‐pack XR‐ODS C₁₈ column (75 × 3.0 mm, 2.2 µm) using gradient elution with mobile phase consisting of 0.1% formic acid aqueous solution and acetonitrile at a flow rate of 0.5 mL/min. Mass spectrometric detection was conducted on a 3200 QTRAP mass spectrometry equipped with electrospray ionization source in negative ionization mode. Quantification was performed using multiple reactions monitoring mode. Calibration curves exhibited good linearity (r > 0.9947) over a wide concentration range for all analytes, and the lower limits of quantification were 10, 5, 1, 5, 1, 5, 1, and 5 ng/mL for geniposide, genipin gentiobioside, honokiol, magnolol, isonaringin, naringin, hesperidin, and neohesperidin, respectively. The intraday and interday precisions at three quality control levels were less than 12.3% and the accuracies ranged from ?11.2 to 10.7%. Extraction recovery, matrix effect, and stability were satisfactory in rat plasma. The validated method was successfully applied to a pharmacokinetic study of the eight analytes after oral administration of Zhi‐Zi‐Hou‐Po decoction to rats.     

Y分支有机聚合物热光开关的研制

利用有机聚合物材料热光效应进行Y分支结构光波导开关的研究和制作，实验结果显示光开关具有小于－20dB的串音，驱动功率为110mW-130mW。同时给出插入损耗的测试结果，并分析了其产生的各种原因。针对器件的开关速度问题，提出了解决方法。     

OPTIMIZATION AND APPLICATIONS OF REVERSE-FLOW CYCLONES

An optimum design approach to reverse-flow cyclones based on the concept of optimizing cyclone dimensions is introduced in this paper. This approach involves optimizing cyclone dimensions by categories, calculating cyclone performance by correlating similitude numbers and optimizing the combination of four cyclone parameters, D, KA,(-d- and vi, which has been proven to be applicable not only for single-stage cyclone, but also for multistage cyclone separators. Applications of the designed cyclones in FCC units and acrylonitrile reactors are also presented.     

基于绝缘体上的硅材料的全内反射型阵列波导光栅器件的设计

设计了一种基于绝缘体上的硅材料的全内反射型阵列波导光栅解复用器年。将一全内反射波导镜引入原弯曲的波导列阵中，该波导镜具有偏振补偿的功能和缩小器件尺寸的特点。在器年数值模拟的基础上，制作了原理性器件，并获得了初步的实验结果。     

Etched-Diffraction-Grating-Based Planar Waveguide Demultiplexer on Silicon-on-Insulator

An optical wavelength demultiplexer with the etched diffraction grating (EDG) on the silicon-on-insulator (SOI) material is demonstrated. Fabricated by the wet-anisotropic-etching method, 90° turning mirrors are used to bend waveguides, and the size of the EDG-based demultiplexer is minimized to only 16×2.5 mm². The crosstalk is below −16 dB. The on-chip loss is about 9.97 dB, which is composed of about 8.72 dB excess loss and 1.25 dB diffraction loss. The polarization-dependent central wavelength shift is below 0.13 nm, and the polarization-dependent loss is about 0.35 dB. The sources of the crosstalk and loss are discussed in details, and the related measures to improve the performance are also presented.     

ANALYSIS ON CYCLONE COLLECTION EFFICIENCIES AT HIGH TEMPERATURES

In order to predict the influence of operating temperature on cyclone performance, an experimental investigation on particle separation was conducted in a 300 mm diameter, tangential volute-inlet and reverse flow cy-clone separator with air heated up to 973 K. The test powder silica has a mean mass diameter of 10 microns and the inlet velocity ranges from 12 m.s-1 to 36 m-s-1. Both the overall efficiency and fractionai efficiency of the cyclone were measured as a function of the inlet velocity and operating temperature. It is shown that at the same inlet velocity both the overall efficiency and fractionai efficiency decrease with an increase of temperature. An analysis of our own data and published results has shown that the fractionai efficiency of a cyclone is a defmite function of such dimensioniess numbers as Stokes number, Reynolds number, Froude number and dimensioniess cyclone inlet area and dimensioniess outlet diameter. A nondimensionai experimental correlation of the cyclone performance, inclu     

跨声速势函数的构成与数值求解

现有的非等熵势函数方法是基于热力学第二定律建立的密度与熵之间的关系式,由动量方程间接或直接计算出熵的变化,再与势函数方程迭代求解。与这种复杂的迭代计算不同,本文建议直接从散度型动量方程计算包含了熵的影响的密度,其与势函数方程迭代便可方便地求解整个流场,采用人工密度和AF2方法,对任意迴转面叶栅内跨声速流动计算的结果表明,本文方法得到的流场与等熵计算相比,激波位置前移,强度减弱,和试验结果较为接近;与计算熵增的非等熵势函数相比,结果是相同的,而计算却比较简单。     

微通道内椭球颗粒惯性聚焦行为数值研究

基于浸没边界-格子Boltzmann方法,对方形截面微通道内椭球颗粒的惯性迁移与旋转动力学行为进行数值研究,发现微通道内椭球颗粒的惯性迁移存在两种主要的运动状态：①翻转状态,即椭球颗粒前进过程中长轴始终在中心对称平面内;②滚动状态,即椭球颗粒前进过程中长轴始终垂直于中心对称平面.研究表明：在低Re数（Re=10）下颗粒以两种状态随流体迁移至平衡位置;在较大Re数（50≤Re≤200）下最终均以翻转状态随流体迁移,随Re数增加,平衡位置先逼近壁面后远离壁面.通过对不同运动状态下椭球颗粒周围的微观流场进行分析,提示该微观流动在颗粒惯性聚焦行为特征中有重要影响,并从流体和颗粒的惯性角度对颗粒不同运动状态的转换机理给出解释.