全息波导显示中输出扩展光栅的衍射效率分布分析

对于全息波导显示系统,为获得连续的输出光瞳而引入的半透半反膜,会在波导中形成阶跃形光强分布,与阶跃形强度分布相匹配的输出光栅衍射效率须为阶跃形分布,这样才能获得均匀的衍射输出强度。为保证衍射角带宽内所有光线均有较佳的输出强度均匀性,提出了一种连续递增的衍射效率分布光栅模型。建立了基于对阶跃形衍射效率分布的分段加权平均和二次曲线拟合的优化计算模型,计算得到了衍射效率分布曲线,并由衍射效率分布曲线计算得到衍射角带宽内不同视场光束的输出光强分布。结果表明,输出光强位置均匀性最小为52.4%,出瞳内角度均匀性达到84.9%。随着分束膜层数的增加,波导阶跃形光强差将会减小,可获得更好的输出强度均匀性。

地区大中型工业企业技术创新效率分布的非参数检验

研究我国大中型工业企业技术创新效率分布的非参数检验问题。首先,借助统计方法筛选评价指标;然后,测度了我国大中型工业企业技术创新效率;最后,运用非参数统计方法检验不同地区效率的分布状况。结果表明,东部地区的大中型工业企业的技术创新投入效率较高,但河北和山东则较低;中西部地区的大中型工业企业的技术创新投入效率普遍偏低,但重庆却有较高的技术创新投入效率且较为稳定;东、中西部地区内部各地区的大中型工业企业的技术创新效率分布存在显著差异;高投入与高产出,低投入与低产出的地区,即使技术创新效率相当,它们的效率分布状况也未必一样。

中子多重性计数器探测效率空间分布研究

针对基于3He的中子多重性计数器探测效率的空间分布情况,本文在中国原子能科学研究院研制的中子多重性计数器装置上,实验研究了不同位置处的探测效率,通过对探测效率实验数据在空腔内轴向和径向变化趋势的分析,提出了采用多元方差分析与最小二乘拟合的方法,建立中子多重性计数器的探测效率空间分布的数学表达式,并研究了采用实验测量点对探测效率进行标定的方法。同时,将本文提出的确定探测效率空间分布的方法拓展应用于AWCC装置的研究。另外,还对探测效率的空间分布情况进行了理论分析,解释了探测效率在径向的边缘效应。

用Delphi5开发高效率的分布式应用系统——提高分布式应用系统效率的几种方法

本文总结出用 Delphi5开发多层分布式应用系统时 ,通过优化数据库存取的设定 ,使用有效率的远程调用方式 ,调整应用程序服务器的执行效率和控制网络流量等来提高分布式应用系统效率的方法。

电动汽车电机驱动系统效率测试方法研究

分析了电动车辆对牵引电机及其控制系统的性能要求,介绍了电机及其控制器的效率计算方法和效率分布特性,提出利用试验测试并结合数学差值得到系统的效率分布,从事了试验研究分析,为电机系统优化和匹配提供了技术支持。

宽高效率区混合永磁同步磁阻记忆电机设计

铁氧体、钕铁硼混合永磁同步磁阻电机相对铁氧体永磁同步磁阻电机,具有较高的永磁磁链,提高了功率密度尤其是弱磁运行时的功率密度,但一定程度上降低了高速、低转矩区的效率。为此,在铁氧体、钕铁硼混合永磁同步磁阻电机的基础上采用一定量的铝镍钴替代钕铁硼,设计成混合永磁同步磁阻记忆电机,在不降低电机弱磁运行功率的情况下,对不同工况下的永磁磁链进行调节,采用铁氧体、钕铁硼和铝镍钴三种永磁材料混合,可有效提高混合永磁同步磁阻电机高速、低转矩区效率。从维持弱磁运行功率和永磁磁链调节两方面对铝镍钴和钕铁硼的相对用量进行设计,对永磁磁链的调节过程和效率分布进行分析,证明了所设计的电机拓宽了高效率区范围,并分析了相关电磁特性。

增益和相位一致性对功率合成效率的影响

发射机在功率合成的时候,由于各固态功率源模块间存在着增益和相位的差异,会导致功率合成效率的下降。针对这一问题,本文通过建立增益和相位的一致性对功率合成效率影响的模型,并结合MATLAB软件进行计算模拟,得到不同增益和相位分布下的最低合成效率分布,为发射机功率合成系统设计提供了具体的相位和增益指标,并为发射机的评估和验收提供了有力的理论依据。

试验粉尘对空气滤清器粗滤效率的影响

评定空气滤清器性能试验根据不同试验标准所使用的试验粉尘也不相同,主要有进口试验粉尘ISO 12103-A2细灰、ISO 12103-A4粗灰和国产试验粉尘270目石英砂。本文对空气滤清器粗滤效率试验、试验粉尘的颗粒尺寸分布进行了检测并做了对比分析,总结了一些技术要点,归纳了试验粉尘对空气滤清器粗滤效率的影响因素。

金融发展的经济增长效率及其分布特征

基于2000—2010年我国31个省域的面板数据,采用非参数Malmquist指数法,测算了我国金融发展的经济增长效率(简称金融效率)及其分布特征。研究结论表明:我国的金融效率偏低且没有明显改变。其中,金融创新效率更是低于金融配置效率;金融效率分布具有较为典型的经济区域特征和金融控制程度特征。金融控制程度影响金融效率的提升,特别是抑制金融创新效率。研究表明,我国金融发展对经济增长的作用仍停留在数量扩张和要素堆积阶段,金融创新效率不足是金融效率提升的钳制因素。

负载口独立控制系统的节能边界

为了找寻负载口独立控制系统的极限节能边界,并明晰其节能机理,建立传统阀控系统和负载口独立控制系统的静态效率与静态能耗模型,利用归一化处理使模型转化为无量纲形式。选取与传统阀控系统可比拟的2种工况,即同泵源压力和同阀口开度,在负载口独立控制系统处于节能极限时(出油阀口全开)进行对比。仿真分析不同工况下2种系统的静态效率与能耗对比情况,并绘制效率分布谱获取全工况下效率分布对比情况。结果表明:同泵源压力下,负载口独立控制系统最多能提升阀控液压系统效率约5.7%,降低能耗约22.7%;同阀口开度下,负载口独立控制系统最多能提升阀控液压系统效率约19.4%,降低能耗约53%。负载口独立控制系统能够降低阀口节流损耗,进而降低阀控液压系统能耗。

变风量多分区空调系统新风量计算

介绍了变风量多分区系统的区域新风需求、新风分布、通风效率和单/双通道多分区循环系统,借鉴ANSI/ASHRAE标准62.1—2004提出的系统新风量计算方法给出了变风量多分区空调系统的新风量计算方法。该方法有助于在新风节能方面拓展设计思路。

铸铜转子双三相异步电动机设计与优化

以新型电动车用驱动电机为设计目标,利用有限元软件建立铸铜转子双三相异步电动机二维电磁仿真模型,计算电机的峰值输出转矩和功率。对比分析铸铜转子与铸铝转子在效率方面的差异,进一步计算电机的效率分布,通过调节定子和转子槽型来优化电机的效率分布,使电机的最高效区域分布在电动车的常用工况区;对比分析对称电压供电情况下,双三相定子绕组与三相定子绕组在一相忽然断路时对电机转矩的影响,并给出双三相电机缺相运行时的控制策略。以电机的实测数据来验证仿真计算的正确性,电机输出特性满足电动汽车需求。

Effect of Surface Potential Barrier on the Electron Energy Distribution of NEA Photocathodes

By calculating the energy distribution of electrons reaching the photocathode surface and solving the Schrodinger equation that describes the behavior of an electron tunneling through the surface potential barrier,we obtain an equation to calculate the emitted electron energy distribution of transmission-mode NEA GaAs photocathodes. Accord- ing to the equation,we study the effect of cathode surface potential barrier on the electron energy distribution and find a significant effect of the barrier-Ⅰ thickness or end height,especially the thickness,on the quantum efficiency of the cath- ode. Barrier Ⅱ has an effect on the electron energy spread, and an increase in the vacuum level will lead to a narrower electron energy spread while sacrificing a certain amount of cathode quantum efficiency. The equation is also used to fit the measured electron energy distribution curve of the transmission-mode cathode and the parameters of the surface barri- er are obtained from the fitting. The theoretical curve is in good agreement with the experimental curve.

平焰燃烧器应用于小型工业炉的实验研究

针对实验室现有的小型燃气室式炉自行设计平焰燃烧器及其燃气和空气管路,搭建工业炉热性能测试的试验台架,通过不同工况下的实验测试,对燃气炉的热平衡及温度分布等性能进行了研究和分析。结果表明,燃气炉的热效率略大于20%,热效率比较低的主要原因是燃气炉的烟气余热没有得到利用;炉膛内的温度不均匀性很大,其原因主要是烟气出口位置布置的问题和燃气炉没有达到热平衡。

无失效数据条件下装备贮存可靠性分析

为解决装备贮存可靠度评估问题,对寿命分布为平均失效率递增类分布(increasing failure rates on the average,IFRA)的装备的贮存可靠性进行分析。首先,针对装备检测过程中可能出现的无失效数据情况,确定了失效概率的先验分布并给出了Bayes估计。然后用加权最小二乘法给出了寿命分布的参数估计,进而得到了装备贮存可靠度的估计和表达式。最后结合实例进行计算,说明了方法的稳定性和可行性,为工程上评估装备贮存可靠度提供借鉴。

Real-valued multi-area self set optimization in immunity-based network intrusion detection system

The real-valued self set in immunity-based network intrusion detection system （INIDS） has some defects： multi-area and overlapping, which are ignored before. The detectors generated by this kind of self set may have the problem of boundary holes between self and nonself regions, and the generation efficiency is low, so that, the self set needs to be optimized before generation stage. This paper proposes a self set optimization algorithm which uses the modified clustering algorithm and Gaussian distribution theory. The clustering deals with multi-area and the Gaussian distribution deals with the overlapping. The algorithm was tested by Iris data and real network data, and the results show that the optimized self set can solve the problem of boundary holes, increase the efficiency of detector generation effectively, and improve the system＇s detection rate.

Effect of Manure on Distribntion of Micronutrients in Rhizosphere of Wheat

A rhizobox system was used to determine the distribution of micronutrients (Fe, Mn, Cu and Zn) acrossthe rhmosphere of wheat (Triticum aestivum). The available contents of Fe and Mn in the rhizosphere wereraised by addition of manure or chemical fertilizer combined with manure, but those of Cu and Zn werehardly affected, which might be an important reason why manure addition could improve the Fe and Mnnutrition status of plants. Several possible mechanisms for the increase of the availabilities of Fe and Mn inthe rhizosphere due to manuring are discussed as well.

Numerical Study on the Influence of Boss Cap Fins on Efficiency of Controllable-pitch Propeller

Numerical simulation is investigated to disclose how propeller boss cap fins （PBCF） operate utilizing Reynolds-averaged Navier-Stokes （RANS） method. In addition, exploration of the influencing mechanism of PBCF on the open water efficiency of one controllable-pitch propeller is analyzed through the open water characteristic curves, blade surface pressure distribution and hub streamline distribution. On this basis, the influence of parameters including airfoil profile, diameter, axial position of installation and circumferential installation angle on the open water efficiency of the controllable-pitch propeller is investigated. Numerical results show： for the controllable-pitch propeller, the thrust generated is at the optimum when the radius of boss cap fins is 1.5 times of propeller hub with an optimal installation position in the axial direction, and its optimal circumferential installation position is the midpoint of the extension line of the front and back ends of two adjacent propeller roots in the front of fin root. Under these optimal parameters, the gain of open water efficiency of the controllable-pitch propeller with different advance velocity coefficients is greater than 0.01, which accounts for approximately an increase of 1%-5% of open water efficiency.

Solution of Wheeler-De Witt Equation, Potential Well and Tunnel Effect

This paper uses the relation of the cosmic scale factor and scalar field to solve Wheeler-De Witt equation,gives the tunnel effect of the cosmic scale factor a and quantum potential well of scalar field, and makes it fit with the physics of cosmic quantum birth. By solving Wheeler-De Witt equation we achieve a general probability distribution of the cosmic birth, and give the analysis of cosmic quantum birth.

Theoretical Approach to Concentration Distribution and Adhesion Efficiency of Fine Particles Around a Rising Bubble in Slurry Systems

Quantitative prediction of distribution function and adhesionefficiency of particles around a rising bubble in slurry systems ispresented in this work. By solving the convection-diffusion equation(Fokker-Planck equation), the influence of Brownian diffusivity offine particles on concentration distribution and adhesion efficiencyis demonstrated with the hydrodynamic force and van der Waalsattractive potential between particles and bubble considered. It isfound that two kinds of mechanism dominate the adhesion process ofparticles on bubble according to different Peclet number or size ofparticles and bubble, as well as other properties of the slurrysystems. In addition, the viscosity ratio of bubble to the suspendingfluid was found to have obvious influence on particle adhesion.