Parallelization of Monte Carlo Code MCACE for Shielding Analysis and Estimation of Its Efficiency by Simulator

An improved coarse-mesh discrete ordinates method has been developed for three-dimensional hexagonal transport calculations of high-conversion light water reactors and fast reactors. This method employs a new weighted diamond difference approximation which is obtained by using the neutron balance equations in divided submeshes. The weight is a function of neutron direction and scaler flux, and this method can be easily incorporated into conventional discrete ordinates transport codes.

The present method was applied to hexagonal fuel assembly calculations of high-conversion reactor and fast reactor core calculations, and the results were compared with those of Monte- Carlo calculations. The values of kefi and power distributions agreed with each other within 0.5 and 3%, respectively, verifying accuracy of the present improved coarse-mesh discrete ordinates transport calculation method.     

运动目标模拟器相参性分析

分析了基于数字射频存储器（DRFM）的运动目标模拟器（MTS）相参性。由于DRFM延时的离散性，引起了MTS输出信号相位的改变，破坏了信号的相参性，使MTS输出信号频谱发生变化，不仅使谱线位置移动，而且还产生了附加的寄生谱线。分析结果表职，延时更新率（Fc）决定了谱线间隔，并通过sinc函数决定谱线的幅度，而雷达信号频率与所模拟目标的速度共同决定谱线的移动。     

电流传输器模拟电感的设计及其在振动控制中的应用

通过电流型运算放大器组成第二代电流传输器与RC元件实现模拟电路的设计,由此搭建压电分流阻尼系统控制机械结构振动.通过软件仿真测试模拟电感电路设计的正确性,并以根部粘贴压电陶瓷片的固支梁结构为例,对该结构的第三阶模态振动控制进行了实验研究和分析,结果表明:所设计的新型压电分流电路具有良好的减振效果.     

Colorimetric evaluation of daylight simulator sources

The color shift of a sample due to a change in illuminant can be expressed either in terms of the CIE General Color Rendering Index, R_a, based on the average for eight color samples, or in terms of the CIE Metamerism Index MI_vis, the average for five pairs (or couples) of samples. It is shown that, in an ideal case where the eight samples constitute four complementary pairs, the value of the average for eight can be predicted accurately from the average for only four of the eight samples. This is approximately also the case for a prediction based on four of the actual eight CIE samples, but in this case there is some uncertainty in the predicted R_a values. For MI_vis, a useful approximation in value can be obtained using only two of the five defined couples. Finally, it is shown that R_a and MI_vis evaluate illuminants in largely the same way.     

Can simulation technology enable a paradigm shift in process control?: Modeling for the rest of us

Commercial process simulation software makes it easy for experts to develop very complex models with thousands of equations. But how well are these models used? Remember the admonition of Box [Box, G. E. P. (1979). Robustness in scientific model building. In R. L. Launer & G. N. Wilkinson (Eds.), Robustness in statistics (pp. 201–236). New York: Academic Press], “All models are wrong, but some are useful”. Are case runs just captured in a report and then filed away? Is the expert the only one who can run additional cases? We believe that process dynamics simulation should be ubiquitous in chemical engineering practice and education. Undergraduate engineers should experience unit operations through a virtual process simulator. In industry, engineers must be able to quickly build dynamic models to study operability and design control strategies. We feel that DuPont has undergone a paradigm shift where engineers are much more likely to use dynamic simulation as part of their day-to-day work. This paper illustrates some of the features that process dynamic simulators need to enable this paradigm shift.     

The nonlinear control of simulator of hexapod parallel mechanism

In order to enhance the innervation fidelity of simulators,a nonlinear controller is developed,which guarantees parallel mechanisms closed loop system global asymptotical stability and the convergence of posture tracking error in Cartesian space. The problems of rapid tracking under the condition of the wide range,nonlinear and variable load are solved. After the nonlinear controller is actually applied to the hexapod parallel mechanisms of simulator,the dynamic-static capabilities of motion system are tested by amplitude-frequency response and posture precision. The experimental results show that the static precision improves ten times and system output amplitude increases and the phase lag reduces with respect to the same input signal in Cartesian space in comparison with the traditional proportional and derivative (i.e. PD) controlling method in joint space. Therefore the nonlinear controller can effectively improve the dynamic-static response performance of the hexapod parallel mechanisms of simulators in Cartesian space.     

小型星模拟器中星图动态显示系统的设计

阐述了星图动态显示系统的工作原理和系统要求,讨论了ＴＦＴ－ＬＣＤ在星图动态显示系统中的应用方法,提出了ＴＦＴ－ＬＣＤ的电路实现方案,对星图动态主要软件的设计进行了分析和研究。     

化工过程仿真培训系统中的换热器模型

本文讨论了化工过程仿真培训系统中的换热器的动态模型，着重比较了两种稳态模拟与动态补偿相结合的仿真算法－基于平均传热温差和基于传热单元数的仿真算法。分析了基于平均传热温差的仿真算法存在的问题，讨论了基于传热单元数的仿真算法中有关参数的确定方法，最后给出仿真实例。     

一种压缩向量集生成法在功耗估计中的应用

在逻辑层功耗仿真基础上，介绍一种返回传输权方法，用该方法来产生一个压缩的向量集．这组压缩向量在进行功耗仿真时可以取代原来由用户给出的或者从描述电路行为特点的程序中取得的函数向量集．实验证明：这种方法不但可以缩短仿真时间，还可以保持非常高的精确度．     

Universal Series and Parallel Immittance Simulators Using Four Terminal Floating Nullors

Most of the presented immittance simulator topologies in the literature realize certain types of inductor–resistor–capacitor combinations using the same configuration. In this study, a series and a parallel immittance simulator employing FTFNs in its most general form are introduced. The presented circuits are universal and able to simulate series and parallel (±G), (±L), (±C) for which all values are independently adjustable. The simulator circuits do not require any component matching constraint, except for the realization of pure inductance. Strong reduction in the number of active and passive elements is possible for special cases. The performance of the proposed universal immittance simulators is demonstrated on two chosen typical application examples by PSPICE simulations.