新型渣罐搬运车

Kirow公司继其成功推出平台型渣罐搬运车之后 ,又开发出了新型U型架系列渣罐搬运车。其有效负载在 40～ 1 0 0吨之间 ,这些全新型的渣罐搬运车秉承了Kirow平台式渣罐搬运车的众多优点 ,工作可靠、安全、循环时间短、操纵简单、维护和运行费用低 ;安全系统配备PLC控制系统、专利技术的超载安全系统和避免误操作的智能系统。其独特之处在于不用辅助液压缸与钢绳系统 ,采用免维护湿式圆盘制动器 ,降低了此车运行费用。此款渣罐搬运车的模式化 ,将标准化的部件组合起来十分方便 ,缩短了交货时间 ,提高了竞争力。新型渣罐搬运车@曹福永…     

采煤机自适应记忆切割

针对以往的采煤机记忆切割技术在我国复杂地质条件下不适用的情况,提出了基于模糊控制理论的采煤机自适应记忆切割技术,设计出了采煤机位置、姿态定位系统和采煤机自适应切割模糊控制系统.该系统可以获取采煤机任意位置处的姿态和状态信息,自动跟踪所记忆的切割路径,基于模糊控制理论对是否截割到岩石进行判断并做出最优的处理方案.通过实验室的路径跟踪实验和西安煤矿机械有限公司的自适应调节实验证明:该技术在实现采煤机记忆切割的基础上能够识别出滚筒到切割岩石时的异常状态,并对牵引速度和滚筒高度做自适应调节,能够满足复杂地质条件下对采煤机的控制要求.     

煤矿辅助运输机械化综述

发展煤矿辅助运输机械化势在必行,也是提高现有矿井效率和效益的关键环节,从高产高效的矿井实践经验来看,采用大型无轨胶轮运输车或搬运车,可以大大提高煤矿矿井的生产效率和效益,当然,在一些矿井中,还存在矿井巷道条件或入井条件受限制的的情况,这时应考虑在辅助运输最薄弱的环节(即盘区和顺槽)创适合理且必要的条件,来使用无轨胶轮运输车或搬运车,另外,在改追或者进行辅助运输系统设计时,一定要注重构建高效的设备运行支持保障系统,这样可以确保运输设备性能最大化,同时发挥经济和社会效益最大化.     

基于物联网的煤矿井下智能综采技术的应用研究

针对煤矿井下综采作业人员多、效率低、安全性差的难题,提出了一种基于物联网的煤矿井下智能综采技术,对井下综采设备组网方案、采煤机智能综采方案、采煤机远程可视化控制方案、采煤机姿态定位与自动调整方案等进行了研究。结果表明该综采技术方案能够有效提升井下综采作业的自动化程度,综采作业效率比优化前提升了37.1%,综采面作业人员数量降低了41.8%,为实现井下无人化综采作业、降低井下综采事故奠定了基础。     

综采工作面回采工艺研究

针对当前煤炭需求量越来越大,采煤设备能力一定的情况下如何提升工作面煤炭的产量,通过对我国煤炭最高年产量的变化和综采技术现状研究的基础上,对比了对拉工作面回采及超长工作面双采煤机单向采煤机工艺的特点,为进一步提升煤矿年产量提供了指导。     

基于CBD的采煤机概念设计方法

为能在较短时间内设计出客户满意的采煤机及其零部件,提出一种基于CBD的采煤机概念设计方法。该方法将以人为中心的设计原则融入传统的案例推理理论中,提出具有用户反馈机制的循环设计流程,集设计规则、k-means聚类索引规则和量化评价规则于一体,将用户评价信息转化为案例效用值反馈给设计系统,由此得到最优设计方案。通过采煤机的工程实例证明了该方法的实用性和准确性。     

国内最大采煤机下线

国内目前最大的采煤机日前在山西太重煤机太矿工业园成功下线。以该套采煤机为代表的“千万吨级矿井高产高效工作面综采成套设备与关键技术攻关”科研项目通过了专家组的评议验收，这是具有自主知识产权的首套大型综采成套设备，达到国际先进水平，结束了我国不能批量生产千万吨级综采成套设备的历史。     

大采高采煤机行走部关键零部件有限元分析

针对采煤机行走部工作环境恶劣,受力较复杂的特点,在分析行走轮和导向滑靴破坏的基础之上,对行走轮和导向滑靴进行有限元分析。结果证明了行走轮和导向滑靴的可靠性与安全性,为采煤机的关键零部件的合理设计提供了一种成本低廉、高效实用的方法。     

论采煤机截齿可靠性

在采煤机和掘进机的滚筒上所用的刀具,通常称为截齿.采掘机中电动机的功率绝大部分都是由截齿来消耗的.截齿是需要经常更换的易损件,对吨煤成本有一定的影响.所以,对于提高截齿的质量、可靠性、强度、寿命和工作性能,正确选用和安装截齿,提高采煤机的生产效率和降低成本有着重要意义.     

出煤矿用电机研制成功

日前，中国北车集团永济电机厂成功研制出煤矿用隔爆型三相异步电动机YBC-400（YJ88A），并取得了煤炭工业上海电器防爆检验站颁发的防爆合格证。该电机以MT476—1996（YBC系列采煤机用隔爆型三相异步电动》，GB3836《爆炸性气体环境用电气设备》等相关国家标准为基础，结合井下实际使用环境而设计制造，具有隔爆性能好、功率大、起动性能优越等优点。主要与采煤机配套使用，     

The importance of the results of pretreatment pelvic lymphographies in the prognosis of carcinomas of the uterine cervix. A critical evaluation of the proposal to classify these tumors according to the TNM system (author's transl)

Between 1966 and 1969, 494 patients with carcinoma of the uterine cervix stages I a to IV were admitted in our hospital for primary treatment. In 420 of these patients with carcinoma of the cervix stage I b to IV, complete results of bilateral pretreatment pelvic lymphography are available. The correlation between the results of the lymphographies, the choice of the operative treatment and the cure rates in these 420 cases are reported. All the correlations between the results of the pretreatment lymphography and the prognosis are described. A positive lymphography was in our series of high prognostic value. A plea is therefore made to include the results of the pretreatment lymphography into the classification of carcinoma of the cervix. Classification of the carcinoma of the cervix into the TNM categories is desirable. Our series is reported in these TNM categories. The advantages of such classification are described. The morbid entity of carcinoma of the cervix becomes more transparent to the observer and the choice of operative therapy becomes easier. The prognosis is more clearly established. The proposals of the TNM committee of the UICC for the classification of carcinoma of the cervix according to the TNM categories and the staging according to these categories are discussed critically.     

An investigation of the effect of porosity and diluents on micropyretic synthesis

A numerical model of combustion/micropyretic synthesis of a composite system is developed. The new features of the model include the consideration of melting of each constituent of the reactants and products and the inclusion of considerations involving dilution and porosity. The effect of porosity is to change both the thermal conductivity and density. The model for the porosity which is considered in this article shows the significance of its effect on the velocity and the type of the combustion front. Different values of porosities are considered for the reactants and products. For an illustrative analysis, a systematic study of the variation of porosity of reactants and products is carried out for the combustion synthesis of TiB₂ and TiC. The numerical results indicate that as the reactant porosity values are decreased, the combustion velocity first increases because of an increase in the thermal conductivity. The combustion velocity, after reaching a maximum, decreases with a further decrease in the porosity. As the porosity is varied, there is a considerable effect on the nature of propagation of the combustion front, which may change from a steady state to an oscillatory mode. Results indicate that as the reactant porosity is decreased, the frequency of oscillations of the combustion front first increase and then decrease with a further decrease in the reactant porosity. The differences in the mechanism for the decrease in velocities at very low values of reactant porosities for the two systems TiC and TiB₂ are identified. The results of considering different values of porosities in the reactants and the product are also presented. For the study of the effect of diluents, the product itself is considered as the diluent. The effect of adding the diluent to the initial reactants is to decrease the combustion temperature and the combustion velocity. The diluent also changes the mode of combustion. An increase in the amount of the diluent results in the decrease of the frequency of oscillations.     

Sucking effect of diaphragm and its significance in drainage of abdominal cavity during hepatic surgery

Investigation of the value of the sucking effect of the diaphragm in 44 patients was carried out. The first group consisted of 28 patients who have not undergone hepatic resection. The second group included patients after hepatic resections of various volume in local pathology. The balloon method in modification of this clinic was used for measurement of the value of the sucking effect. In patients of the first group the value of sucking effect was almost two times more under the right cupula of the diaphragm (130.33 + 4.78 mm of water column) in comparison with the left infradiaphragmatic space. It is responsible for presence of the slot between the right half of the liver and the diaphragm, which aggravates the sucking effect. In the second group of patients the value of the sucking effect under the right diaphragmatic cupula was practically the same as in patients of the first group. After right-sided hemihepatectomy the value of the sucking effect under right cupula of the diaphragm has significantly diminished. After resection of the right lobe of the liver as well as after left-sided hemihepatectomy, or without them, the value of sucking effect under left cupula of the diaphragm did not significantly differ. The investigations showed that vacuum-aspiration with vacuum of not less than 150 mm water column should be used for effective drainage of infradiaphragmatic space.     

Rolling of metal balls

The rolling of balls (diameter 93 and 125 mm) of precise mass in helical grooves is simulated by means of QForm-3D and DEFORM-3D software. A model of a virtual rolling mill is created. Analysis of the stress state at characteristic points along the rolling axis focuses on the effective stress, the components of the stress tensor, and the mean normal stress. The mass of balls rolled on new and worn rollers is measured. The quality of internal metal layers is verified, and the hardness of rolled balls over the vertical and horizontal symmetry axes is measured. Modeling of ball rolling shows that the hot blank (a rod of hot-rolled steel) is satisfactorily captured by the rollers. Rolling is stable, without slipping. The blank completely fills the grooves; no gaps are observed between the metal and the walls. The crosslinks between the balls are completely eliminated within the rollers. The crosslinks are cut by the rim of the rollers and pressed into the body of the ball. The individual balls continue to roll along the finishing section of the groove; the stubs of the crosslinks are smoothed; and a completely shaped ball with a smooth surface emerges from the rollers. In modeling the stress–strain state, all the components of the stress tensor are negative. In other words, all the components of the stress tensor are compressive in rolling of the balls. Statistical analysis of the data from weighing of the rolled balls (diameter 93 and 125 mm) shows that the mass deviates from the required value by no more than 1%. Measurement of the hardness over the diametric cross section of the balls shows that there is no decline in hardness in the internal layers. That indicates high quality of the ball core.     

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...     

Reliability-Based Optimal Design of Truss Structures Using Particle Swarm Optimization

In this work, the particle swarm optimization method is employed for the reliability-based optimal design of statically determinate truss structures. Particle swarm optimization is inspired by the social behavior of flocks (swarms) of birds and insects (particles). Every particle’s position represents a specific design. The algorithm searches the design space by adjusting the trajectories of the particles that comprise the swarm. These particles are attracted toward the positions of both their personal best solution and the best solution of the swarm in a stochastic manner. In typical structural optimization problems, safety is dealt with in a yes/no manner fulfilling the set of requirements imposed by codes of practice. Considering uncertainty for the problem parameters offers a measure to quantify safety. This measure provides a rational basis for the estimation of the reliability of the components and of the entire system. Incorporating the reliability into the structural optimization framework one can seek a reliability-based optimal design. For the problems examined herein, the reliability indexes of the structural elements are obtained from analytical expressions. The structure is subsequently analyzed as a series system of correlated elements and the Ditlevsen bounds are used for the calculation of its reliability index. The uncertain-random parameters considered in this work are the load, the yield-critical stress; and the cross sections of the elements. The considered design variables of the optimization problem are the cross-sectional areas of the groups, which control the size of the truss, and the heights and lengths that control the shape of the truss. The results of the optimization are presented for a 25-bar truss and a 30-bar arch and the robustness of the optimization scheme is discussed.     

In vitro expression of n-cadherin adhesion molecule during early cardiac morphogenesis

The aim of the present study was to investigate, "in vitro", the degree of organogenetic potentiality of the cells of the cardiogenic area during the early developmental stages of the chick embryo. Embryos from between the end of the presomitic stage to the 8 somite stage were studied. The subcephalic fold was cultured in liquid medium for up to 7 days. After 24 hs of culturing, an extended migration ring was observed. In the explants, from 3 somite stage, onwards, beating masses were noted, the shape and size of which suggested a vascular-like structure. Sections of the cultures were processed for the detection of the N-Cadherin adhesion molecule. The observations stated that the diffusion and intensity of expression of this receptor is related to the stage od development of the embryo. Cultures from the presomitic stage to 3 somite stage did not express the molecule. Instead, expression took place in those cultures of embryos at the 3 somite stage, onwards. In the cultures to which the antiserum against N-Cadherin had been to the medium, the formation of vascular-like structures was affected. The changes depended on the age of the embryos. These observations suggest that the expression of the N-Cadherin is related to the potentiality of the presumptive myocardic cells to organize themselves, at least "in vitro", to form a well-defined tridimensional structure. The expression of the adhesion molecule and the potentiality of the cells to build tubular structures were transient features, "in vitro" in our cultures. This suggests that "in vivo" the expression of the N-Cadherin must be aided by factors which, at present, are unidentified.     

Ecology of flea groups of the species conformis (Siphonaptera: Pulicidae: Xenopsylla) of the fauna of Russia and adjacent countries (review)

Within the boundaries of the former USSR, the northern part of the conformis group distribution is located. It spreads over the arid regions of the Trans-Cacucasus, Pricaspijckaja lowland, Kazakhstan and Middle Asia. In this area 10 species and subspecies occur. They are mainly parasites of gerbillins. Unlike many other Siphonaptera the conformis fleas, when in the host's home, do not concentrate in the nest but inhabit the passages of burrow and food chambers throughout the year. On this reason the preimaginal development and existence of the adults take place not at the temperature of the habitable nest, which is heated by the host body, but at the temperature of the soil at a depth of burrow. The temperature threshold for preimaginal development of conformis fleas is reported to be 10-12 degrees. Temperature below the threshold is fatal for all immature instars. On the contrary the imago can survive at freezing temperature. The annual cycle of the conformis fleas is characterized by the presence of adults throughout the year. They breed in the warmer season and overwinter in the state of reproductive diapause. In this state the fleas are able to attack the host and to feed but do not deposit eggs. In the north deserts the reproduction begins at the early April and terminates at the early September. Southern, the reproductive period is longer. Furthermore, the complete interruption of the reproduction in the autumn-winter time may be absent as it was observed in X. gerbilli gerbilli and X. hirtipes in the south of the Middle Asia. On the other hand it is noted that in southern deserts the rate of oviposition falls in the most hot time. The number of generation per year in the conformis fleas varies from 2-3 in north deserts to 6-7 in south ones. The flea populations peak in late autumn when the insects cease to bread. The high abundance is maintained until springtime. After the diapause is ceased and the fleas begin breeding their abundance declines. In the late spring and early summer the emergence of adults begins and the populations increase. In a mild of summer the second fall takes place and then the fall is replaced by the autumnal peak. On their main hosts the conformis fleas prevail over all other species of Siphonaptera especially for warmer time when their quota among other fleas does not descend as a rule below 90% but more oftently it approaches to 100%. The fleas of this group and especially species parasitizing Rhombomys opimus are remarkable for the high level of their abundance. In the northern deserts in the periods of the most high abundance (late autumn, winter and early spring) the number of fleas per burrow occupied by family of Rh. opimus exceeds usually 1000 specimens and sometimes it can reach several thousands. In the southern deserts the abundance of the fleas is lower but the period of their active parasitizing is longer. In the species parasitizing Rh. opimus it is shown that in a complex burrow only some part of fleas has the possibility to feed regularly. In the spring and summer the percentage of fleas daily attacking the host varied from 17 to 86% and from 10 to 150 ectoparasites feed daily on one animal depending on the quantity of fleas and of hosts in the burrow. The number of attacking fleas is regulated by behaviour of the hosts, which change the used parts of burrow when the fleas are crowded there.     

Efferent and afferent connections of the nucleus lateralis posterior thalami ("pulvinar") in the albino rats (author's transl)

The efferent and afferent connections of the lateral posterior nucleus (LP) of the albino rat were investigated light microscopically with the silver-degeneration-methods and the HRP-methods as well. The results are: 1. The main projection region of the LP is the area of 18a of the peristriate visual cortex. Most degenerating axons terminate in layer IV. A few fibers pass layers III and II and terminate in layer I. It is not sure if there are also terminating fibers in layer IV. We could not find a topistic relation between LP and area 18 a. 2. We observed a small number of degenerating fibers in area 17, too. 3. A part of the degenerating fibers runs to the temporal cortex end enters area 20. 4. There is no evidence for a projection of the LP to both the subcortical regions and to the superior colliculus. 5. The majority of the LP's afferent fibers originates - on the subcortical level - from the superior colliculus. Especially the lamina III (Str. opticum) of the ipsilateral and of the contralateral side is here the source of fibers terminating in the LP. 6. Other subcortical sources of fibers terminating in the LP are: the pretectal region, the ventral part of the LGN, the Zona incerta, the thalamic reticular formation, and the dorsal raphe nucleus. 7. There exists a fiber projection of the area 17 to the LP. The axons originate mainly from pyramidal cells in layer V. It is discussed whether the area-17-fibers terminating in the LP are collaterals of the fibers terminating in the superior colliculus. The projection of the area 18a to the LP is of greater importance. The axons of this area originate mainly from cells of the layer VI. It becomes obvious that the thalamic relay-station of the second visual pathway seems to project nearly exclusively to the neocortex. In contrast to the dorsal LGN, however, the LP is not only a simple relay-station for visual information as also non-visual information arrives here. The morphological basis for these inputs has not yet been clarified completely. We have to take into consideration as well as the connections with the superior colliculus and the pretectal region and the cortical connections. It is remarkable that there exists also a projection of LP-fibers to a region outside the classical visual cortex. In mammals of higher evolution that kind of projection extends increasingly. It is discussed if - under comparative-anatomical aspect - the morphological changes in the pulvinar region are an expression of the neocorticalization, whereas the morphological changes in the dorsal LGN reflect mainly the functional specialization of the visual system.