DY-2001A型纳米级电子束曝光机中静电偏转器的设计

基于纳米曝光要求和JSM-35CF型扫描电镜,设计了一组上下偏转器长度不一致的静电偏转器,使偏转灵敏度大大提高.采用二阶有限元法计算了八极静电偏转器的轴上场分布.高精度的场分布有利于高级像差.为了使系统的总体像差最小,结合具体电子光学系统,用最小二乘法对偏转器的激励强度、转角及其在系统中的位置进行优化,得到直至五级分量的像差.动态校正后,偏转场为80μm×80μm时,束斑分辨率约为3.2 am;偏转场大小为1 mm×1 mm时,束斑分辨率约为29.8 nm.结果表明,应用该组静电偏转器的电子光学系统的分辨率满足纳米曝光的要求.     

北京FEL电子束时间分辨能谱仪的控制及慢扫描系统

叙述了北京ＦＥＬ谱仪中的控制与扫描系统的基本功能以及用于偏转电子束的慢慢转线圈的磁分析及其微秒脉冲电流源性能。     

低屋面横向通风牛舍倾斜挡风板流场数值模拟

针对低屋面横向通风牛舍在实际运行时会出现牛舍内气流不均匀的问题,提出了一种改变牛舍上部挡风板倾斜角度的方法来改善牛舍内空气的均匀度.利用fluent软件建立挡风板与垂直方向成不同夹角的牛舍三维模型,设置风机和湿帘为边界条件.利用计算流体动力学方法对牛舍内的空气流场进行三维数值模拟,并获得了挡风板的最佳安装角度.结果表明,当挡风板与垂直方向夹角为60℃时,牛舍中气流分布最为均匀,奶牛生存高度的气流速度也最合适.     

Hydraulics of a multiple slit-type energy dissipater简

With the constructions of high dam projects in China, the energy dissipation downstream of a dam becomes a serious concern. In this study, a multiple slit-type energy dissipater, with different reduction size slits in the outlet, is developed on the basis of conventional slit-type energy dissipaters, aiming to enhance the energy dissipation through the turbulence and the friction between the different layers of the jet flow and the air entrainment due to the increased surface of the flow to the air. The hydraulic characteristics of the energy dissipater are experimentally investigated by means of three sets of physical models in nine cases, to characterize the geometric parameters with suitable performance. The main concerns are the flow regime, the jet flow trajectory, the energy dissipation, the cavitation characteristics, and the flow choking. The results indicate that the dissipater enjoys a high energy dissipation ratio with suitable hydraulic performance comparing with the conventional slit-type energy dissipaters.     

Performance enhancement of rooftop turbine ventilators using wind deflectors

Rooftop turbine ventilators are widely used to improve indoor air quality in residential buildings and industrial complexes. This study presents an approach to enhance the operational performance of commercially available turbine ventilators using wind deflectors. Wind deflectors guide the wind flow to minimize the forces acting on the turbine blades in a negative direction, thereby increasing the rotational speed and exhaust ability of turbine ventilators. Two different prototypes were built and experimentally analyzed, one with adjustable size that covered up to half of the turbine, and one made of flat metal sheets, which were placed in front of the turbine. Compared with traditional turbine ventilators, the results of the two different prototypes showed an average increase in air extraction rate at different wind speeds of 34 and 11%, as well as an average rise in the rotational speed of 36 and 33%, respectively. The present study clearly demonstrates the high potential of wind deflectors to enhance the efficiency of turbine ventilators, and shows that a cover-style wind deflector is the more efficient design.     

Moldflow在汽车挡风网基座注塑成型过程中的应用

以Autodesk Simulation Moldflow作为分析平台,采用结构较复杂的某汽车天窗挡风网基座为分析对象,对其表面出现的外观问题进行分析;运用Moldflow软件,模拟零件的注塑成型过程,通过调整浇口阀开启顺序、优化工艺参数等预测出零件的缺陷。根据分析的结果,进行了现场试模和调试,零件的优化结果符合预期。经实践验证,新的工艺能提高零件的品质和性能,满足客户的使用要求,具有一定的参考和应用价值。     

制袋自动生产线中的纸边导向装置

介绍制袋自动生产线中的纸边导向装置 ,分析导向机构的原理 ,介绍其驱动元件及控制系统     

玉环电厂1000MW机组选择性催化还原脱硝装置的设计特点

为了减少锅炉NOx排放对大气的污染,华能玉环电厂对其4×1 000MW机组进行了脱硝工程改造。由于改造工程主要增设了选择性催化还原(selective catalytic reduction,SCR)脱硝装置,为此介绍了SCR脱硝系统所选用的工艺构成和流程特点、设计参数、总体布置情况,并对该工程中相关设备的改造进行了描述;同时通过冷态模型实验和计算机模拟计算,为改造工艺的优化提供了有利保障。     

应用于频谱分析的高分辨率声光偏转器

介绍了应用于频谱分析的高分辨率声光偏转器，描述了偏转器的原理、设计，给出了光波长650nm，带宽50MHz，分辨率20kHz，峰值衍射效率74％（线偏振光）的实验结果。     

泵站前池导流板整流措施数值模拟研究

针对前池流场是具有强紊动的自由表面流动的特点,CFD数学模型应用VOF方法,采用Realizablek-ε的紊流模型。以导流板设置位置、倾斜角度与板下悬空高度为因子拟定多个数值试验工况,通过数值模拟分析比较整流效果,给出了较合理优化的导流板布置方案。