不均匀

Based on the depth research on extension array manifold of uniform circular, for some uniform circular arrays which had subarrays with the nature of rotational invariance and had the nature of central symmetry two ESPRIT algo-rithms were presented, the first algorithm reduced one time of SVD, the second algorithm avoided parameter pairs.

在深入研究均匀圆阵扩展阵列流形的基础上，针对某些均匀圆阵的扩展阵列中含有旋转不变性的子阵列组以及中心对称性质，提出了2种基于均匀圆阵的二维ESPRIT算法，第一种算法减少了一次奇异值分解，第二种算法避免了参数配对。

In the homogeneous model, the function of tendons is assumed to be uniform in some approximated way in order to form an equivalent homogeneous material within concrete. The formulation of the homogeneous model is same with that of general FEM for common continuum, let alone the elastic matrix being resultant of that of tendon and concrete. The computation is simple, but the approximate assumption makes this method cannot be generalized, because it only represents the constitution and function of tendons in such a rough way, that the numerical results are inaccurate. In the combined model, the function of tendon is considered by the stiffness matrix with rod element, then add it into the stiffness matrix of concrete by a rational way.

均匀类单元是设想将钢筋均匀弥散于整个单元中，使其成为一种连续均匀材料单元，这种单元的与一般有限元的单元刚度矩阵推导过程一样，只不过其弹性矩阵由混凝土和钢筋两部迭加而成的，此类单元刚阵计算简明而又不会扩大计算规模，但均匀弥散只是为计算简单而作一种假想，不贴近单元构造实际，也不符合实际作用效果。

Our main work is as follows: the stable laser mode theory in uniform plasmas is extended to non-uniform plasma cases; the discussion of the sufficient and necessary conditions for laser self-focusing in uniform plasmas is developed to non-uniform plasma cases; a quantitative approach to judge the impact of different plasma density distribution on laser self-focusing is proposed; the evolution properties of asymmetric laser filed in non-uniform and uniform plasmas are discussed and mechanisms that symmetric channel-like plasmas can confine the laser centroid around the plasma channel axes and symmetrize initially asymmetric laser beams are proposed; the formation of solitary standing wave in moderate plasma density is studied by PIC simulations and can be explained by stimulated Raman scattering of laser beams in plasmas.

主要工作为：把均匀等离子体中激光的稳定模理论推广到横向非均匀等离子体情形；把均匀等离子体中激光自聚焦的充分和必要条件的讨论推广到横向非均匀等离子体情形；给出横向密度分布不同的等离子体影响激光自聚焦的定量判据。讨论了初始不对称的激光场在横向非均匀及均匀等离子体中的演化特性，并提出了具有对称腔道结构的等离子体箍缩激光质心和对称化初始不对称激光场的物理机制。用粒子模拟讨论了激光场在等离子体中形成孤立驻波的过程，认为前向受激拉曼散射是发生此现象的可能机制。

The paper make an intensive study of the key link in spinning mill ── the quality test and production control using capacity evenness tester which is presented by USTER TESTER, covering the analysis of relevant test results and practical application for the evenness test,the spectrogram types,the calculation of the weave length showed on a spectrogram and caused by mechanical faults,the determination and control of the evenness indexes,as well as the requirement and the plan for spinning quality control.

摘 要：探讨了纺纱质量测控的中心环节──使用以USTER TESTER为代表的电容式条干均匀度仪器测定条干均匀度时的结果分析及实际应用。其中涉及电容式条干均匀度仪的测试结果分析及应用、波谱图的分析及应用、设备的机械问题在波谱图上所造成的不匀波长的计算、纺纱条干均匀度指标及控制、纺纱质量控制方案及要求等几个方面的内容。

The simulation results of the cylinder-block model were given in the article, consistent with that of Middlemen"s. It was shown that the block part could improve the uniformity of the flow distribution. The analysis of the flow field of some materials with different power-law factor in the die designed by Mckelvey was close to that of Mckelvey"s. It was shown that the flow distribution was uniform in the die that can producesheets with 1200mm in width. During the analysis the flow channel was divided into several parts to get the details about the fluid flow in each area. A conclusion was drawn after analyzing the influence of the die pressure on the flow distribution, that the higher pressure is good for the output and bad for the uniformity of the distribution. Simulation of the die applying the cylindrical main runner showed the fact that when the cylinder replaced the cone the change of uniformity was trivial. The uniformity of the non-block flow channel was so poor that the block in the proper position of the die channel was necessary. The project of the die for the wider sheet was put forth, and the analysis of the fluid flow in the die was shown.

本文模拟了圆柱管缝隙流模型的三维流动场，得到了与Middlemen结论一致的流动均匀性，并通过模拟直观地展示了采用阻尼块可以改善挤出均匀性的现象；分析了多种幂率指数的流体在Mckelvey等人设计的流道模型中的流动分布，得到了与Mckelvey的分析结果接近的压力降和流量偏差；本文建立了1200mm幅宽机头流道的三维有限元模型，并逐个分析各个区域和多个截面的流动分布状况，由此揭示了1200mm幅宽L-型机头流道内的流北京化工大学硕士学位论文动分布基本均匀，并在分析了机头压力对于挤出流动分布的影响后得出结论：较高的机头压力可以获得较大的产量，但是不利于物料均匀分布；模拟了采用圆柱管主流道时机头流道内的流动分布，得出结论：主流道由圆锥管改为圆柱管时对流动均匀性影响不大，通过设置适当的阻尼仍然可以达到挤出平衡；模拟了两端进料式圆柱管无阻尼流道的流动均匀性后得到结论：两端进料式无阻尼结构的流动均匀性较差，宽机头中仍然有必要设置阻尼块；确定宽幅机头流道的基本方案，并设计了一种宽幅防水卷材挤出机头流道的结构，通过流动模拟表明该种结构的流动均匀性较好；考察了宽幅机头对于不同厚度片材的挤出适应性，得到结论：当生产不同厚度的片材时，阻尼块高度需要调整。

ABSTRACT The diffused phase transition and frequency dispersion of Pb-based complex perovskite relaxor ferroelectrics of PZN, PMN etc. were studied by the measurements of spectum of dielectric permittivity with temperature at different frequencies as well as by the means of differential thermal analysis and ferroelectric hysteresis technique. It was found that there are various polarization relaxors which cause DPT characteristics.

本文利用介温谱的测量，差热分析和电滞回线对以PZN，PMN为代表的铅系复合钙钛矿型弛豫铁电体的相变弥散和频率色散性等弛豫特性进行了分析研究，对产生弛豫的根本原因提出了新的看法，认为这类材料的DPT特性并不是一种由成份及结构不均匀的统计分布所造成的&准&弛豫现象，而是由材料本身弛豫机制所致。

Results Leiomyosarcoma on Abdomen usually solitary and welldefined LSA from the stomach (n=12),colon(n=5),ileum and jejunum (n=4),mesentery (n=2),with an average diameter of 6.5cm.

结果：平滑肌肉瘤常单发，大小不一，行态多变，发生于胃12例，结肠5例，小肠4例，肠系膜2例，平均直径为3.8 cm~6.5 cm，大多边缘清晰，伴肠管及肠系膜血管移位，平扫表现为等密度，稍高密度14例，周边等密度，中央低密度6例，混杂密度2例，增强后明显强化12例，边缘明显强化7例，不均匀强化4例。

The results show that the zinc coating is eroded mostly, and some red rust and black rust appear on the substrate in the environment of oxygen supplied intermittently.

结果表明：在间歇通O2的情况下，锌层大部分被腐蚀，而且在基体上有一些红锈和黑锈产生，镀锌板表面的腐蚀产物呈现着不均匀的针状物；而在间歇通N2时，镀锌板的锌层脱落面积较少，基体上没有产生红锈，腐蚀产物呈大块状；在间歇通O2和通N2的情况下，镀锌板的腐蚀速率先增后降，在200 h时，前者的腐蚀质量损失速率是后者的2倍左右；镀锌板附着库尔勒泥浆时的腐蚀过程受氧去极化过程控制。

The inhomogeneous spatial and temporal distribution of precipitation has great influence on basin runoff.

在我国，特别是北方地区，降水的时空分布相当不均匀。

The results shows severe field distortion at conductor and earthing top of insulator which stress is in more than 10 times higher than at central part due to effect of distributed capacitance of H.V.

得出受杆塔和高压导线分布电容的影响，绝缘子导线侧和接地侧的电场畸变严重；导线侧和接地侧的电场强度均高出绝缘子中部十几倍，电场分布极不均匀。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。