高铬铸铁磨球对比试验研究

笔者为验证所用新型高铬铸铁磨球生产工艺合理性,选取了低铬铸铁磨球、普通高铬铸铁磨球和新型高铬铸铁磨球进行化学成分、内部组织结构、力学性能和耐磨性能进行对比分析,得出了新型高铬磨球的耐磨性是低铬铸铁磨球的1.53倍,是普通高铬磨球的1.12倍,耐磨性能较好。通过实践检验新型高铬磨球球耗和破碎率均优于普通高铬磨球和低铬铸铁磨球,为实际生产提供理论指导。     

矿用磨球种类及性能研究现状

为了系统地了解各类磨球性能及使用情况,对磨矿行业中磨球种类进行了介绍,并对不同种类磨球的研发和使用情况做了分析.详细介绍了铬系铸铁磨球、球墨铸铁磨球以及锻(轧)磨球的化学成分要求与成形工艺;对不同种类磨球的材质、力学性能、显微组织等方面作了综合的对比与分析;简述了不同材质规格磨球的性能差异;介绍了改善磨球性能的途径和生...     

高锰钢轧球初步试验

球磨机是矿山破碎铁矿石的重要设备,球磨机的磨矿介质——磨球又是球磨机的重要部件,磨球的质量将直接影响矿山部门的经济效益。因此,对磨球的要求既要有一定硬度又要有一定的韧性,这对于铸铁材质的磨球是做不到这一点的,为此我们研试一种高锰钢磨球,从炼钢到轧球,改变了传统的铸造制球工艺,并且测定了高锰钢磨球的各项性能。这种磨球不仅延长了使用寿命,降低磨球消耗,节省能源,而且为我们选择磨球材质和制球工艺开辟了新途径。     

热处理工艺参数对矿用磨球力学性能的影响研究

为实现矿用磨球强韧性的进一步提升，本文研究了不同热处理条件下磨球的力学性能、显微组织形貌及物相特征。结果表明，不同热处理条件下磨球的显微组织均由马氏体、碳化物和残余奥氏体组成。基体的组织特征、碳化物的形态和分布、残余奥氏体的占比共同影响磨球性能：随着奥氏体化温度的提高，磨球硬度先升高后降低，冲击韧性连续下降；随着奥氏体保温时间的延长，磨球的硬度和冲击韧性均先升高后降低；随着回火温度的提高，磨球硬度连续下降，冲击韧性波动性上升；随着回火保温时间的延长，磨球硬度变化不大，冲击韧性呈下降趋势。对于实验磨球，较佳的热处理参数为：950℃保温3 h,快速入油淬火后300℃保温3 h进行回火，所得磨球洛氏硬度62.58 HRC,冲击功4.92 J,相比产品磨球可分别提高5.2%和51.9%。     

磨球的腐蚀与磨损

分析了研究磨球的腐蚀与磨损的意义,阐明了磨球 磨损的规律（ 与 磨球直径的 ２ ～３ 次方有关） 和矿浆流变特性对磨损的重要影响,以及磨矿中存在的腐蚀及其严重性,并指出 必须合理选择磨球材料。     

提高钨合金铸铁磨球使用性能的研究

以我们近年开发的钨合金铸铁磨球为基础,探讨了采用稀土变质处理以提高其使用寿命的可能性。研究结果表明:钨合金铸铁磨球经适量稀土变质处理后。共晶碳化物由网状分布变成断网状分布,磨球冲击韧性显著提高,硬度略有上升,耐磨性明显改善,冲击疲劳寿命显著提高,磨球各项指标,达到甚至超过了高铬铸铁球的水平。可见用稀土处理提高钨合金铸铁磨球使用性能将是可行的。     

轧制磨球的选材及制造研究现状

介绍了轧制磨球的材料、性能及其制造工艺,分析了轧制磨球的发展趋势。轧制磨球向高碳低合金钢、高碳中锰钢、合金白口铸铁等多元化发展,高效率、高质量是轧制磨球生产线的发展方向。     

多种经营

耐磨高铬磨球生产技术1　概　述在球磨机用的各种磨球中 ,锻、轧钢球的产量和消耗量最大。其材质大多为中、低碳合金钢。中、低碳合金钢锻、轧磨球用于磨煤的单耗为 1 0 0～ 2 0 0ｇ/ｔ,磨铁矿的单耗为 1 0 0 0ｇ/ｔ,普碳钢磨球磨铁矿的单耗高达 2 0 0 0ｇ/ｔ。高铬磨球因其组织结构特殊 ,耐磨性能比碳钢磨球提高 6倍以上 ,比锻、轧的合金钢磨球提高 3倍以上 ,用于磨铁矿 ,单耗仅为 30 0ｇ/ｔ左右。高铬磨球可取代现有的多种磨球 ,广泛用于铁矿、有色金属矿、非金属矿、水泥、陶瓷、火力发电、化工等行业 ,需求量相当大。)采用本技术可生产…     

离心铸造白口铁磨球的研制

探索了成本较低有较好耐磨性的低合金白口铁磨球的最佳创作工艺;通过对静态与离心浇注条件下磨球的组织性能对正,进一步研究了离心铸造磨球的耐磨性。     

论球磨机磨球的磨损规律

简要说明了影响球磨机磨球磨损的主要因素,提出了较完善的磨球磨损规律的表达式。     

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     

Epidemiological assessment of the system of indices characterizing the quality of vaccine preparations

The authors discuss the methodology and the method of formation of the medico-technical requirements to newly-elaborated or modified vaccine preparations. The following are considered among the principal parameters responsible for the formation of the quality of the vaccines: the prophylactic activity, the extent of the injurious effect, the technological and the exploitation properties. A close association of these parameters in the determination of the quality of the vaccine and the dependence of the efficacy of its use on the character of the epidemic situation was shown. A possibility of using the method of calculation of the efficacy of immunization for detection of the main (leading) parameters of the quality of the vaccine elaborated which should be used in composing the medico-technical requirements. It is emphasize that one of the principal directions of the investigations is the elaboration and the assessment of the correctness of the immunological and laboratory methods of standardization and control of the methods of objective measurement of the parameters forming the quality of the vaccine preparations.     

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。