坡流式挤压涂布嘴腔体几何参数对涂布宽向均匀度的影响

本文导出了坡流式挤压涂布嘴腔体结构几何参数及阻尼缝隙加工误差对涂布宽向均匀性影响的近似分析表达式。结果表明,试图用腔体横截面积沿宽向的某种分布规律,以实现涂布的宽向均匀性,是难以达到的。而只要采用适当的阻尼缝宽,确保阻尼缝宽的加工精度,尽量扩大乳剂分配腔的横截面     

薄金属屏蔽导体上孔缝电磁泄漏的理论分析

根据惠更斯原理，对孔缝的电磁泄漏功率给出一理论计算公式，该公式可用于弥补在频率较高时将孔缝等效为电偶极子或磁偶极子进行计算时造成的偏差。     

涂布嘴衣架腔流体力学基础

本文讨论为了使涂布横向均匀,令涂布嘴分配腔入口流体经腔体和缝隙至与缝隙出口等距的等高线的任一流线上压力降都相等,腔体与缝隙应遵循的变化规律的流体力学基础。     

非接触搭接结构电磁屏蔽特性的数值分析

非接触搭接是电子设备箱体常见的连接形式,搭接处会不可避免地存在缝隙,而缝隙是电磁泄漏的主要途径,将致使箱体屏蔽效能降低,故有必要探索增强腔体屏蔽效能的方法．以几种典型非接触搭接金属箱体为研究对象,在平面波激励下,利用传输线矩阵法（TLM）和波导理论,对搭接长度、缝隙宽度、缝隙长度等参数对箱体屏效的影响进行了定量的数值计算和定性的理论分析,结论表明通过减小缝隙宽度、增加搭接长度和螺钉分段均可提高箱体屏效．同时计算分析了不同搭接形式对箱体屏效的影响,提出了能够实现高屏效的搭接结构途径,并结合矩形波导理论得到采用弯折搭接结构也能够显著提高箱体屏效的结论．研究结果可为电子设备的电磁屏蔽设计提供依据．     

复合材料地雷壳体X波段HPM辐照效应实验研究

采用不锈钢纤维填充工程塑料制备复合材料地雷壳体,内部放置磁引信并连接电引火头,在微波暗室中进行X波段HPM辐射下毁伤效应实验。数值计算屏蔽效能>20dB,实验结果验证计算。当壳体存在半径5mm以下圆孔时,实验结果与数值计算均表明其对屏蔽效能影响较小;当壳体存在矩形孔缝时,其长度l、孔缝与极化方向之间角度为最大影响因素。复合材料壳体有助于提高磁引信地雷在战场高功率电磁环境下的生存能力。     

错缝结构对隔墙传声损失的影响研究

缝隙的存在一直制约着传统隔墙结构隔声性能的提高。以错缝双层石膏板结构为研究对象,分别研究了错缝深度和错缝距离对隔墙传声损失的影响。结果表明,错缝结构比直缝结构具有更好的隔声性能;缝隙深度的影响主要取决于隔墙面密度和声波传播路径的变化;而当错缝距离与隔墙厚度接近时,其隔声量最高,这是由于声能在墙体和错缝缝隙中的透射程度相当,从而弥补了缝隙在隔墙结构中的透声"短板"。     

用丝束电极研究16Mn钢的缝隙腐蚀行为

用丝束电极研究了0．51mol/L NaCl溶液中16Mn钢的缝隙腐蚀特征。采用电位、电流和阻抗扫描技术测试了缝隙内电位、电流和溶液电阻Rs的分布特征,发现缝内的电位和电流分布具有显著的不均匀性,缝内电极电位要负于缝外,缝内为阳极,缝外为阴极,从缝隙边缘向缝隙中心,电极电位沿径向先负移而后正移,阳极电流则是先增加而后下降。阻抗测量表明：缝内的Rs要较缝外约大20倍,而倍内的极化电阻Rp则较缝外小,且缝内中心区的腐蚀速率小于缝内边缘区。     

室温海水中钛钌阳极缝隙内的电化学行为

研究了钛凶阳极在室温海水介质中缝隙内的电化学行为。结果表明：钛钌阳极在室温海水中工作时，其缝隙内介质会发生严重酸化，缝内电位低于缝外电位，缝外工作电流密度达到１０ｍｊＡ／ｃｍ＾２，缝隙内ｐＨ值下降到１．５左右，缝内、外电位差达１．０Ｖ。钛钌阳有在室温海水介质中工作时不产生缝隙腐蚀。     

条缝涂布咀腔体设计研究

查阅历年来国外有关条缝涂布咀腔体结构的专利和文献,研讨了条缝涂布咀各组成部分的作用,得出条缝涂布咀设计和制造的关键所在.     

天平发生跳针时的调修方法

天平在使用过程中会出现跳针现象,跳针的产生是由于刀缝的前后不均匀造成的,调修方法是集中精力调修三刀前后缝隙,依照先中刀,后边刀的顺序进行。调修原则是使三刀刀缝前后一致,即针对刀缝的具体情况,降低缝隙大的一方的支销,升高缝隙小的一方的支销。     

Shielding effectiveness of a rectangular enclosure with finite wall thickness and rectangular apertures by the generalised modal method of moments

An efficient and accurate technique based on modal method of moments (MoM) is introduced, which takes into account the perforated wall thickness in the calculation of the shielding effectiveness (SE) of a rectangular enclosure. To achieve this, the modal expansion of the magnetic currents at both sides of the aperture is considered and the volume inside the aperture and the enclosure walls is represented by a proper Green's function that is incorporated in the original modal MoM. The SE of an enclosure with single and multiple rectangular apertures with various wall thicknesses is examined. A very good agreement among the results of the proposed method and experimental results is observed. It is shown that wall thickness affects the calculated SE, and hence, the accuracy and precision of SE prediction is increased by taking it into consideration. In addition to being efficient, the method shows convergent results even for very small thicknesses.     

电磁脉冲对计算机机箱的耦合效应

利用时域有限差分法对电磁脉冲与计算机机箱的耦合效应进行研究。建立计算机机箱的物理模型,通过分析机箱内的电磁场随时间的变化曲线和耦合系数随频率的变化曲线,得到电磁脉冲对计算机机箱的耦合规律：电磁脉冲可以通过孔缝进入机箱内部,对机箱内元件的瞬间影响较大;机箱内的耦合能量是先增加后减小;元件的存在使得机箱的屏蔽效能降低,谐振频率下降。研究结果可用于计算机的电磁兼容设计和解决干扰防护问题。     

Design and performance characteristics of an electromagnetic interference shielded enclosure for high voltage Pockels cell switching system

An electro-magnetic interference noise shielding enclosure for Pockels cells for high speed synchronized switching has been set-up and tested. The shielding effectiveness of the aluminum enclosures housing the Pockels cells and the electronic circuitry has been measured using a high impedance probe and is found to be ∼50 dB. This ensures a noise-free and synchronized electro-optic switching in an Nd:glass re-generative amplifier of chirped pulse amplification based table top terawatt laser system. resigned from RRCAT     

Numerical Simulation on the Shielding Efficiency of Magnetic Shielding Enclosures in the ITER Applications

Magnetic shielding needs to be employed to ensure proper operation of some electronic equipment which are sensitive to external magnetic interference, such as cryogenic valves located inside the ITER feeder cubicles. This paper is concerned with the shielding efficiency of the magnetic shielding enclosures. A 3-D theoretical model for Fe-Ni alloy magnetic shielding enclosures based on finite element method (FEM) is obtained with the nonlinear law of magnetization. The influence of shielding materials, enclosure configurations, single or multi- layer designs, and apertures on the shielding efficiency is investigated. It is shown that the proposed model can predict the shielding efficiency of shielding devices well with nonlinear magnetize relation, and some recommendations for an optimized magnetic shield design in the ITER feeder cubicles are given.     

Index class apertures--a class of flexible coded aperture

A class of flexible coded apertures, called index class apertures, is presented. The configurations are shown to possess similar properties to the geometric apertures of Gourlay and Stephen [Appl. Opt.22, 4042 (1983)], and it is demonstrated that the modified uniformly redundant arrays (MURAs) are a special case of the index class apertures. The apertures are shown to offer both a larger range of throughput values and better imaging capability than is available to the geometric apertures, while at the same time possessing more rigidity of structure than other designs, such as the MURAs and the uniformly redundant arrays.     

Image analysis of modified Hamming aperture: application on confocal microscopy and holography

Digital truncated and obstructed Hamming apertures are used in confocal laser scanning microscope (CLSM) to improve the resolution. The resultant point spread function (RPSF) and the coherent transfer function of the defined microscope, using the modified Hamming apertures, are computed. The mammographic images are used in the CLSM to test resolution of the investigated apertures. The image is computed from the modulus square of the convolution product of the RPSF and the complex amplitude of the object. A comparison with the images obtained in case of circular uniform apertures is investigated. Another application on holography allows the recognition of the modulated Hamming apertures.     

Nanolithography using high transmission nanoscale bowtie apertures

We demonstrate that bowtie apertures can be used for contact lithography to achieve nanometer scale resolution. The bowtie apertures with a 30 nm gap size are fabricated in aluminum thin films coated on quartz substrates. Lithography results show that holes of sub-50-nm dimensions can be produced in photoresist by illuminating the apertures with a 355 nm laser beam polarized in the direction across the gap. Experimental results show enhanced transmission and light concentration of bowtie apertures compared to square and rectangular apertures of the same opening area. Finite different time domain simulations are used to explain the experimental results.     

加挂井槽技术的研究与应用

为解决现有海上平台存在的预留井槽不足的问题,研究和开发了加挂井槽技术。面对海上平台的现实难题,通过对平台空间条件、钻井方式、平台结构及平台系统能力等的分析和研究,提出和确定加挂井槽的可行性,细化和完善加挂井槽的相关设计并将设计方案应用于工程实践。实践证明:加挂井槽解决了现有海上平台预留井槽不足的问题,具有结构简易、工程周期短、投资成本低等特点,能满足增打调整井的要求,经济社会效益显著。     

碳毡电路模拟吸波复合材料的研究

分别研究了含矩形碳毡电路屏和“十”字形碳毡电路屏吸波复合材料的微波吸收特性，并对碳毡电路屏的吸波机理做了初步的探讨。结果表明，碳毡电路模拟吸波材料的吸波性能与电路屏阵列单元的结构和尺寸密切相关。矩形电路屏阵列单元中矩形缝隙的长或宽增大，材料的吸波性能提高；矩形缝隙之间的距离增加，材料的吸波性能降低。本实验条件下当矩形缝隙的长、宽和间距分别为24、12和6mm时，材料可获得8．56GHz的有效带宽和-25dB的最大反射衰减。“十”字形电路屏阵列单元中“十”字形缝隙的臂长或臂宽增大，材料的吸波性能提高；“十”字形缝隙之间的距离增加，材料的吸波性能降低。“十”字形缝隙的臂长、臂宽和“十”字形缝隙之间的距离分别为16、8和6mm时，材料的有效带宽7．2GHz，最大反射衰减-26．2dB。