T2-H62搅拌摩擦焊接技术

在自行改造的搅拌摩擦焊机上通过大量试验,研究了T2-H62搅拌摩擦焊接技术,优化了搅拌头的材料、形状及尺寸,通过SNR（信噪比）试验设计,计算出紫铜和黄铜搅拌摩擦焊接工艺参数显著性顺序,并通过拉伸试验、硬度试验及弯曲试验测试了T2-H62搅拌摩擦焊接接头的力学性能,最终优化了搅拌摩擦焊接工艺参数。     

2台SN388遥测仪远距离同步施工的几点认识

SN388遥测仪是世界上较完善的地震仪器之一。随着勘探难度的提高和勘探市场的不断扩大，对该仪器的性能也提出了更高的要求。本文就施工中2台SN388仪器之间的同步以及如何灵活运用它的应用软件，作了简单介绍。     

A General Performance Model of Structured and Unstructured Mesh Particle Transport Computations

The performance of unstructured mesh applications presents a number of complexities and subtleties that do not arise for dense structured meshes. From a programming point of view, the handling of unstructured meshes has an increased complexity in order to manage the necessary data structures and interactions between mesh-cells. From a performance point of view, there are added difficulties in understanding both the processing time on a single processor and the scaling characteristics when using large-scale parallel systems. In this work we present a general performance model for the calculation of deterministic S_N transport on unstructured meshes that is also applicable to structured meshes. The model captures the key processing characteristics of the calculation and is parametric using both system performance data (latency, bandwidth, processing rate etc.) and application data (mesh size etc.) as input. A single formulation of the model is used to predict the performance of two quite different implementations of the same calculation. It is validated on two clusters (an HP AlphaServer and an Itanium-2 system) showing high prediction accuracy.     

SN388中的以太网技术

在说明以太网的概念及特征的基础上，给出了SN388的网络组成及其设计容量，介绍了SN388中以太网的数据原理及网络测试方法。     

A comparative study on optimization methods for experiments with ordered categorical data

When conducting experiments, the selected quality characteristic should as far as possible be a continuous variable and be easy to measure. Due to the inherent nature of the quality characteristic or the convenience of the measurement technique and cost-effectiveness, the data observed in many experiments are ordered categorical. To analyze ordered categorical data for optimizing factor settings, there are three widely accepted approaches: Taguchi’s accumulation analysis, Nair’s scoring scheme and Jeng’s weighted probability scoring scheme. In this paper, a simpler method named the weighted SN ratio method for analyzing ordered categorical data is introduced. A case study involving optimizing the polysilicon deposition process for minimizing surface defects and achieving the target thickness in a very large-scale integrated circuit can demonstrate the four approaches. Finally, comparative analyses of efficiency for employing the four approaches to optimize factor settings are presented according to simulated experimental data that are normally, Weibull and Gamma distributed. From the results, it is obvious that the weighted SN ratio method has the properties of easy computation and uses one-step optimization to obtain the optimal factor settings. Its efficiency is slightly less than that of the scoring scheme, better than that of the accumulation analysis and the weighted probability-scoring scheme.     

基于SN8P2308微控制器的液晶显示接口设计

针对SONIX新型微控制器SN8P2308特点,提出了利用SN8P2308设计具有LCD显示的中小型消费电子产品的一种方案,并介绍了系统的硬件接口电路和软件设计流程。该设计方案不仅能有效地降低系统成本、提高系统稳定性、缩短开发周期;而且可以出色地完成LCD显示驱动及系统控制的双重任务,从而节省了专用LCD驱动电路的硬件开销。     

Structural refinement of cast magnesium alloys

Abstract

The structure of cast magnesium alloys (grain size and precipitate morphology and size) affects the properties of the products and the scope for use of the alloys. The structure can be controlled by minor additions of inoculants, which are largely determined on the basis of the composition of the alloy concerned. The present paper reviews the scientific background of structural refinement by inoculation and its application to Mg–Zn, Mg–Al, and Mg–Al–Si alloys.     

Evaluation of Reactivity Worth of Air Filled Beam Tubes in a Small Neutron Source Reactor by 3-D Transport Calculations

Four air filled beam tubes are present in the small pool type ²³³U fuelled, BeO and water reflected neutron source reactor KAMINI under construction in IGCAR, Kalpakkam. The positive reactivity insertion possible due to the accidental ingress of surrounding water into these empty beam tubes was estimated using the 3-D transport code TRITAC. To save computer time and also to highlight the effects caused by filling of air gaps with water, a similar but symmetrical core with more beam tubes was also studied in detail. Microscopic cross sections were derived from WIMS library and assembly homogenization was performed using a computer code SMAXY. Condensed eight group cross sections were used in TRITAC.

During the study reported here, need was found for the use of tight flux convergence criterion in TRITAC for getting reliable estimates of air to water worths. From the study of the symmetrical core, it is found that the presence of outer water reflector significantly reduces the air to water worth of these beam tubes. Further, the air to water worth of these beam tubes is quite small when the region where water replaces air is, beyond 15 cm from core boundary. Thus it is inferred that the total air to water worth of all beam tubes in the KAMINI reactor will be small compared to the total delayed neutron fraction of ²³³U.     

电冰箱温度自动测试系统数据采集模块的设计与应用

介绍了电冰箱温度自动测试系统中，以总线为基础的数据采集模块的设计方案，该数据采集模块的功能、硬件电路及工作过程、软件设计方法以及数据交换功能的实现。传感器模块的主要作用是进行数据采集，数据处理，接收上位机的测试指令，完成数据传输以及校验等工作。实际安装运行中数据采集模块具有结构简单、转换速度快、高精度、高可靠性、成本低等特点。     

三维并行首次碰撞源模块研制

为了解决首次碰撞源方法对于大规模网格计算效率低以及近源区存在较大计算误差的问题,研制了三维并行首次碰撞源模块。该模块采用区域分解方法实现三维首次碰撞源并行计算,利用自适应源区网格加密方法降低近源区的计算误差。计算结果表明,并行计算有效地提高了计算效率,140核并行计算时,并行效率可达66.89%,自适应源区网格加密方法很好地降低了近源区的计算误差。