水平连铸的拉坯曲线及工艺特点

本文介绍了结晶器固定式水平连铸机连铸时的钢液凝固特点,以及由该特点所决定的必须采用与一般连铸不同的拉坯制度。文中还介绍了水平连铸拉坯曲线的类型和选用准正弦拉坯曲线及拉坯参数的实际工艺效果。     

交流拉矫电机与变频器的选择

讨论了变频调速时拉矫电机工作特性的变化，探讨了如何正确选择和匹配交流拉矫电机和变频器。     

梅山连铸机最大拉速和冶金长度探讨

针对梅山连铸机最大拉速和冶金长度的设计提出不同的看法，认为带液芯单点桥直下的连铸机最大拉速和冶金长度的设计原则不同于全凝固单点矫直、带液芯多点矫直和带液芯连续桥直情况下的最大拉速和冶金长度的设计，并分析了原因。     

拉矫线拉矫纹产生原因分析与控制

针对冷轧生产中严重的拉矫纹缺陷,分析拉矫纹的产生原因,通过控制机组工艺参数,调整设备参数(包括退火,矫直和原材料管理等),达到了改善拉矫纹的目的,保证了产品质量。     

镀锌机组拉矫工艺参数的优化

针对C320热镀线上的拉矫机存在的没有充分发挥拉矫机组对带钢板形的改善能力导致彩涂基板形质量较差等问题,围绕拉矫机的机理以及拉矫机与板形的相互关系展开了深入的研究,对拉矫机工艺参数进行优化,大大提高了板形质量。     

拉伸弯曲矫直机破鳞功能的研究

分析总结了拉矫机破鳞理论，研究了拉矫机工艺参数与破鳞效果之间的关系，提出了酸洗拉矫机工艺参数优化的准则，同时就拉矫机在破鳞方面的发展提出自己的看法。     

拉矫机在八钢热镀锌生产线上的应用

介绍了拉矫机在热镀锌生产线上的作用 ,以及八钢股份公司板带热镀锌生产线拉矫机设备、拉矫机热镀锌钢带性能的影响和生产中应注意的问题。     

SLD-140水平连铸机拉坯曲线的研究

对SLD－140水平连铸机目前使用拉坯曲线进行了运动学和动力学分析，从中得出影响拉坯机提高拉坯频率的主要原因是拉坯过程中加速度变化的过渡过程。     

整体式水平连铸拉坯辊装置的研制与应用

分析了可分式拉坯辊装置在水平连铸拉坯生产中存在的问题；介绍了整体式拉坯辊装置的研制和使用情况。整体式拉坯辊装置具有结构轻便简单．安装更换方便，使用寿命长，能有效提高铸坯质量．降低成本及明显提高水平连铸机生产效率等优点。     

大型进口直流电机拉弧原因分析及处理

着重介绍了大型直流电机产生拉弧的原因和解决拉弧的方法和效果。     

Evolution of the epidemic process as a form of solution to its internal contradictions

The author formulated the main contradition of the epidemic process consisting of contradiction between the interaction of the motive forces of the epidemic process, since this contradiction at the same time served as the imperative condition of the origination and as the cause of the subsequent arrest of the spread of infection. The main contradiction of the epidemic process is expressed in reduction of the number and limited activity of the sources of infection, attenuation or arrest of the mechanism of transmission of the causative agents, formation of immunity in the population, the appearance of hereditary resistance in the hosts to the causative agent of the infection. The action of the principal internal contradiction of the epidemic process in the course of evolution conditions genetic variability of the causative agents of the infectious diseases, intensification of the mechanisms of excretion of the parasites from the host organism, and increase of their resistance in the external environment, formation of latent forms of infection.     

Model system of binaural hearing. III. Binaural processing of information about short sounds

A model of neuronal structures of the medial superior olivary nuclei and inferior colliculus performing the determination of the direction on the source of the short (shorter than 10 ms) sound signals is presented. In the model the difference between the moments of the arrival of the two informational messages formed on the stage of monaural information processing is calculated. The result of this calculation is the firing probability of the primary detector (the neuron of the medial superior olivary nucleus). Because of the internal noise the curve of this probability as a function of the direction on the source is smoothly sloped. The estimation of the direction is the result of the statistical processing of the responses of the primary detectors ensemble. The direction on the source of sound is coded by a position of the secondary detector (the neuron of the inferior colliculus) on the direction "scale".     

STG-12变辊距型钢矫直机的设计计算

针对变辊距矫直机具有不同于恒辊距矫直机的结构特点 ,给出变辊距型钢矫直机辊数、辊距的确定方法 ,并计算出各辊的弯曲力矩及矫直力 ,最后求得设备电机功率。通过设备的具体运行证明 ,变辊距结构对改善设备的受力状况及提高型钢矫直质量十分有利     

连铸方坯中心线凝固行为波动现象及变化规律

连铸坯中心线区域钢液的凝固行为与中心偏析缺陷的形成及控制密切相关。基于中碳钢连铸方坯纵断面的实际凝固组织,以中心偏析点内部二次枝晶间距计算局部冷却速率,揭示了铸坯中心线局部冷却速率的波动特征。结合连铸三维凝固模型,研究了铸坯中心线固相率波动引起局部冷却速率波动并最终影响铸坯中心组织和性能的均匀性的机理;对不同工况铸坯中心线固相率和局部冷却速率波动的周期性进行了分析对比,提出了连铸坯凝固终点位置的周期性波动机理并得到了不同拉速下凝固终点波动距离的判断方程,对于所选连铸方坯,凝固终点波动距离为25.0～27.5 mm;在此基础之上,研究了拉速对中心线固相率波动程度的影响规律,并分析了凝固终点波动距离变化对末端电磁搅拌(final electromagnetic stirring, F-EMS)和轻压下(mechanical soft reduction, MSR)作用均匀性的影响。结果表明,拉速由1.8 m/min提高至2.4 m/min后,虽然液相穴长度增加可能增加整体偏析程度,但铸坯中心线固相率波动程度降低了20%,这有利于减轻中心线偏析沿拉坯方向的波动性,提高铸坯中心质量的均匀性。并...     

Networking for nurses in today''s turbulent times

Craniocerebral injuries involve changes in the vascular plexuses and ependyma of the ventricles, and the severity of these changes varies, depending on the duration of the posttraumatic period and severity of the injury. Analysis of the time course of pathomorphological changes in the cerebral ventricular structures extend our notions on the role and impact of liquor circulation in the pathogenesis of craniocerebral injury. Structural changes in the vascular plexuses may disorder the function of the blood-liquor barrier and promote the development of hydrocephalus. Changes in the structure of the ependymal membrane may involve dysfunction of the liquor-encephalic barrier of the inner surface of the brain and promote the development of brain edema.     

Functional analysis of patients who have had a modified Van Nes rotationplasty

Electromyographic analysis of gait in eight patients who had had a modified Van Nes rotationplasty was performed to compare the activity of the flexors and extensors of the ankle on the side of the operation with that of the flexors and extensors of the knee on the normal, contralateral side. The resemblance in the activity of the extensors was more pronounced than that of the flexors. In three patients, the angle of flexion of the knee throughout the gait cycle was the same on the side of the rotationplasty as on the normal side. There was more symmetry in the swing phase than has been reported for patients who have had an above-the-knee amputation. The strength of the dorsiflexors of the ankle on the side of the rotationplasty was 68 percent and that of the flexors was 71 per cent when compared with that of the muscles of the normal ankle.     

机床液压系统常见故障及使用维护方法分析

机床液压系统通常,下含义判断产生故障的原因。本文通过对机床液压系统常见故障进行分析,从机床液压系统振动和噪音、液压系统的冲击、液压系统中的“爬行”、液压泵出现吸空情况、液压系统温度上升五个方面进行介绍,提出诊断方法,并且介绍机床液压系统的使用和维护注意事项,希望可以帮助相关工作人员排除故障问题,保障机床液压系统的正常运作。     

采场充填料浆流动与离析规律的试验研究

为研究采场充填料浆流动规律及充填料浆离析分层对充填体强度的影响规律,开展了充填料浆流动相似模拟试验及采场原位充填体力学强度测试试验,研究结果表明：单点下料时充填料浆流动终态坡面趋向于正态分布。流动过程中充填料浆产生离析分层现象,主要表现为充填体物料的粒径沿料浆流动方向呈先增大后减小的趋势,充填体强度沿料浆流动方向呈先减小后增大再减小的倒转“S”形趋势。采场原位充填体强度在下料口附近与标准试块强度接近,在采场中间位置附近的充填体强度最小,在距离下料点采场长度7/10左右的位置充填体强度达到最大值。研究成果能够为充填采场下料管的数量及位置设计提供依据,从而保证充填体的整体质量。     

矿山地质环境调查评价技术方法的研究

党的十八大以后,生态文明建设作为中国特色社会主义建设的重要组成部分,对生态环境保护和治理提出了高标准,而矿山地质环境保护与治理是生态文明建设的主要内容之一,保护与治理工作开展前必先查明矿山地质环境现状。调查评价作为前期工作的主要手段之一,调查的范围、精度与评价技术方法的科学性、创新性,对矿山地质环境保护与治理工作成效起着决定性作用。     

Alternative operative exposures of the posterior aspect of the humeral diaphysis with reference to the radial nerve

An anatomical study was performed to define the course of the radial nerve in the posterior aspect of the arm, with particular reference to its relationship to operative exposures of the posterior aspect of the humeral diaphysis. In ten cadaveric specimens, the radial nerve was found to cross the posterior aspect of the humerus from an average of 20.7 +/- 1.2 centimeters proximal to the medial epicondyle to 14.2 +/- 0.6 centimeters proximal to the lateral epicondyle. As it crossed the posterior aspect of the humerus in each specimen, the nerve had several branches to the lateral head of the triceps; however, no branches were found innervating the medial head of the triceps in the posterior aspect of any of the specimens. At the lateral aspect of the humerus, the nerve trifurcated into a branch to the medial head of the triceps, the lower lateral brachial cutaneous nerve, and the continuation of the radial nerve into the distal part of the upper arm and the forearm. Three operative approaches were performed in each specimen. The posterior triceps-splitting approach exposed an average of 15.4 +/- 0.8 centimeters of the humerus from the lateral epicondyle to the point at which the radial nerve crossed the posterior aspect of the humerus. For the second approach, the radial nerve was mobilized proximally to allow an additional six centimeters of the humeral diaphysis to be visualized. The third approach (the modified posterior approach) involved the identification of the radial nerve distally as it crossed the lateral aspect of the humerus, followed by reflection of both the lateral and the medial heads of the triceps medially. This exposure permitted visualization of 26.2 +/- 0.4 centimeters of the humeral diaphysis from the lateral epicondyle proximally. The results after use of the modified posterior approach in seven patients were also reviewed.