Petri net based scheduling

Timed Petri nets can be used to model and analyse scheduling problems. To support the modelling of scheduling problems, we provide a method to map tasks, resources and constraints onto a timed Petri net. By mapping scheduling problems onto Petri nets, we are able to use standard Petri net theory. In this paper we will show that we can use Petri net based tools and techniques to find conflicting and redundant precedences, upper- and lower-bounds for the makespan, etc. This is illustrated by a Petri net based analysis of the notorious 10×10 problem due to Fisher & Thompson (1963)     

Influence of adsorption on the measurement of diffusion coefficients by Taylor dispersion

The effect of adsorption on the measurement of diffusion coefficients by the Taylor dispersion technique is investigated by modifying the governing equation to account for reversible, nonequilibrium adsorption. The resulting two-dimensional equations are solved by an explicit finite-difference technique. Experimental data for the acridine carbon dioxide system indicated that acridine adsorbs on the walls on the tubing and these data were investigated with this model. The influence of carious parameters including the number of sites and the rates of adsorption desorption was investigated by conducting a parametric sensitivity analysis on the model. It was found that adsorption of the solute on the wall of the tubing could produce an error as high as 35% on the measured diffusion coefficient compared to the actual diffusion coellicient. Examination of the influence of each of the parameters will enable Inure investigators to reduce the effect of adsorption in the measurement of diffusion coefficients by Taylor dispersion.     

钠化焙烧钒渣时氯化挥发镓的热力学分析

本文讨论了６００～１２００Ｋ范围内使用ＮａＣｌ作为添加剂焙烧钒渣时氯化发镓的热力可靠性。结论是：氯氧比的大小与溶性钒酸钠生成有直接联系，ＮａＣｌ和Ｎａ２Ｏ。Ｖ２Ｏ５平衡时的氯氧比最大；在氯化钠作用下，镓主要生成ＧａＣｌ３挥发，计算得到的ＧａＣｌ３的生成压相当大。     

抗盐降滤失剂SDX的研究与应用

介绍了抗盐降滤失剂SDX的合成方法与现场应用简况,评价了SDX的抗温、抗盐、防塌及配伍性能。试验结果表明,SDX能耐150℃以上的高温,可抗盐至饱和,具有良好的降滤失和抑制性能,与其它处理剂的配伍性好,适用于各种水基泥浆。     

中小型变压器供电电机起动方式的选择

通过分析和计算及实例，从允许电压降范围和电动机母线电压校验两方面叙述了电动机起动时如何合理地选择起动的方式。     

Gelling of alginate fibres

Equipment was developed to measure the time for complete gelling of sodium alginate fibres in calcium chloride solution, taken as the time to achieve maximum tensile strength. The effects of fibre diameter, alginate concentration, alginate composition and calcium chloride concentration on gelling time were investigated. A diffusional model, developed to predict the gelling time, agreed with experimental results except for the effect of calcium ion concentration which was modelled empirically.     

五强溪水电站缆索起重机的安装与使用

五强溪水电站主体工程混凝土浇筑垂直运输在大坝两岸分高、低层布置４台平移式２０ｔ缆索起重机。其中２台高缆从德国引进，属世界上首次采用全遥控的缆机，同时也是国内塔架最高的缆机；２台低缆属我国目前自行设计制造安装的规格最大、速度最高的缆机。     

9．5－32mm波段大气衰减随仰角变化的实验研究

在实测和分析３２、１４．６、１２．５和９．５ｍｍ波段大气衰减的基础上，研究了大气衰减随仰角变化的规律；讨论了仰角为３～９０°时计算大气衰减的简化计算公式；给出了大气等效高度与地面水汽密度的关系式，对大气衰减和等效高度的实测值与理论值进行了比较和分析．     

强度型光纤传感器的信号检测系统

本文阐述了一种可提高强度型光纤传感器测量精度的检测系统。该系统利用同一检测电路交替检测信号、参考通道的输出信号，并将信号、参考两通道的检测结果相除，从而消除了因发光二极管光源波动及检测电路系统不稳定所带来的误差。采用同步相关技术抑制了噪声，提高了输出信噪比。实验证明，当时间常数ＲＣ为０．０５Ｓ时，采用该检测系统可获得优于千分之一的零点稳定性和优于２×１０３的输出信噪比。     

纤维共晶生长界面前沿三维扩散场解析

修正Ｊａｃｋｓｏｎ和Ｈｕｎｔ关于在垂直生长方向截面上溶质扩散各向同性假设，求解三维Ｌａｐｏｌａｃｅ方程，获得纤维共晶生长界面前沿三维稳态扩散场，并证明Ｊａｃｋｓｏｎ和Ｈｕｎｔ的二维模型是实际生长的二维简化和一阶近似，并用丁二腈（ＳＣＮ）一梓脑（ＣＡＭ）纤维共晶系统计算生长界面前沿溶质分布。