用微机计算电子衍射径向分布函数

本文介绍用微机计算非晶态高聚物电子衍射径向分布函数(RDF)。运用二次样条函数分段拟合及傅氏积分的数学方法,通过 BASIC 程序,只要输入初始实验数据即可自动解算且连续得到与各运算阶段相应的曲线图及其运算结果.     

Techniques for estimating test length under random test

When a circuit is tested using random or pseudorandom patterns, it is essential to determine the amount of time (test length) required to test it adequately. We present a methodology for predicting different statistics of random pattern test length. While earlier methods allowed estimation only of upper bounds of test length and only for exhaustive fault coverage, the technique presented here is capable of providing estimates of all statistics of interest (including expected value and variance) for all coverage specifications.Our methodology is based on sampling models developed for fault coverage estimation [1]. Test length is viewed as awaiting time on fault coverage. Based on this relation we derive the distribution of test length as a function of fault coverage. Methods of approximating expected value and variance of test length are presented. Accuracy of these approximations can be controlled by the user. A practical technique for predicting expected test length is developed. This technique is based on clustering faults into equal detectability subsets. A simple and effective algorithm for fault clustering is also presented. The sampling model is applied to each cluster independently and the results are then aggregated to yield test lengths for the whole circuit. Results of experiments with several circuits (both ISCAS '85 benchmarks and other practical circuits) are also provided.This work was done while the author was with the Department of Electrical Engineering, Southern Illinois University, Carbondale, IL 62901.     

轴对称问题线元上分布奇点的诱导速度势和诱导速度

本文给出轴对称问题线元上高次分布源和偶极在无界域中的诱导速度势和诱导速度的计算公式,可供用分布奇点法求解轴对称势流问题时参考.     

Determination and Health Implication of the Erucic Acid Content of Broccoli Florets, Sprouts, and Seeds

The erucic acid content of broccoli florets, sprouts, and seeds was found to be about 0.8, 320, and 12100 mg/100 g, respectively. Using the erucic acid limit established for canola oil in the U.S.A. and Canada as a guideline, the estimated dietary intake of erucic acid from florets and sprouts was considered of little consequence, whereas in seeds a relatively small amount (about 35 g/wk) equaled our calculated exposure limit for erucic acid. Additionally, the most complete fatty acid distribution yet published for the various forms of broccoli are presented.     

尾流受扰下复杂体形高层建筑的风压分布特性

本文结合汕头粤东信息大厦的风洞试验,详细分析了复杂结构断面建筑物在其尾流受到下游结构干扰下的风压分布特性。试验表明:处于受扰物体尾流边界上的施扰物体可以降低来流在受扰物体上的分离速度,从而使最大负压系数降低。当施扰物体处于被扰物体尾流边界的某些位置时,被扰物体表面的最大负压系数受到显著影响,最多可降低45%。文中还对典型断面结构进行了进一步的试验研究,在验证以上的结论同时,试验结果也显示,施扰建筑位于被扰结构临近的较大区域,其风压增大15%以上,最大可增大39%。本文所得的一些结论可为相应的工程提供参考。     

储层横向相变对剩余油分布的影响

处在构造边部、低部位的商５－５井，在改注水井排液中发现不含水的高产这种非常规现象，由此引起对地质因素的分析。浅湖相沉积的主体是滩砂微相，它可细分为“滩脊”和“滩侧”，其中“滩脊”砂体的泥质含量低，孔隙度、渗透率都较高，而“滩侧”则泥质含量高，物性差。在从“滩脊”砂体向“滩侧”过渡时，极易形成类似于砂体尖灭的岩性封堵，造成剩余油富集，而“滩脊”不一定就在构造的高部位。陆相沉积的砂体非均质性很强，孔隙度和渗透率在横向上的变化很大，高部位的油层水淹，低部位的油层不一定就高含水，这是因为砂体横向上的非均质性，使同一时间单元沉积的砂体很可能不连通。基于这些分析，地质工作者不妨运用沉积微相的原理在构造的低部位或边部寻找剩余油富集区，商５－５井的现实给了我们很好的启示。     

Purification and Characterization of an Endoprotease from Melon Fruit

An endoprotease was purified from melon fruit (Cucumis melo L.) by ammonium sulfate precipitation, gel filtration and ion-exchange chromatography using t-butyloxycarbonyl-Ala-Ala-Pro-Leu p-nitroanilide as a substrate. The molecular weight was estimated as 26,000 and isoelectric point pH 9.5. It preferentially hydrolyzed peptide bonds of the carboxyl terminal sides of Leu, Ala, His, Gin, and Am. Activity was strongly inhibited by diisopropyl phosphofluoridate, indicating the serine protease nature of the enzyme. The migration distance on electrophoresis, molecular weight and substrate specificity differed from cucumisin, a known protease from melon. This unusual protease may have potential for special food treatment applications.     

步行机攀登横杆的受力模型及分析

针对４足步行机器人的横杆攀登过程，在考虑弹性变形的基础上利用刚度矩阵建立其受力模型，并通过计算机仿真对攀登过程的不同情况进行了分析，其结果为具有攀登功能的步行机构结构设计及控制算法确定提供了理论依据。     

配送中心单品拣货模式及其效能分析

紧扣拣货作业的关键目标,介绍了8种低成本的单品拣货模式,并从生产力指标和人员配置两个方面对各种模式的效能进行了计算分析,能为配送中心拣货系统的设计和选择合适的单品拣货模式提供依据.     

Reliability‐based estimation of the survival of Listeria monocytogenes in chorizos

Reliability analysis is especially important when critical decisions are to be made involving potentially severe adverse consequences such as foodborne illness. Owing to uncertainty associated with the parameters controlling survival of Listeria monocytogenes in chorizo (a Mexican‐style sausage), the time needed to reduce the count by a certain number (n) of logs (t_nD) is probabilistic. In this paper the first‐order second‐moment (FOSM) method based on Taylor series expansion is used to derive the expected value and standard deviation of t_nD as function of the operating conditions (random variables) affecting survival, namely initial water activity (a_w0) of the sausage batter, storage temperature (T) and airflow velocity (F), along with their uncertainties characterised by their means and coefficients of variation. For any given n the derived t_nD probability distribution enables one to determine an estimate of t_nD for any desired level of reliability or confidence level, such as 50% (median value), 95%, 99%, etc. Among the conclusions drawn were: (i) the variability associated with T and F has a minor effect on estimating uncertainty in t_nD, whereas the reliability of t_nD estimation is greatly influenced by the uncertainty in a_w0; and (ii) the uncertainty in a_w0 has the greatest impact when a_w0 of the sausage formulation exceeds 0.90. The approach used and discussed in this paper can be applied to any survival/inactivation study to incorporate the effect of uncertainty in the various extrinsic and intrinsic parameters on the survival kinetics of the pathogen in a food system under evaluation. Copyright © 2006 Society of Chemical Industry