美国IDEX集团MagnusTMA系列气动双隔膜泵增加了新成员

美国IDEX集团日前宣布MagnusTM A系列气动隔膜泵产品添加了新成员:1ft(25mm)A系列标准负荷气动隔膜泵。原有的A系列铝合金气动双隔膜泵有2ft(51mm)和3ft(76mm)两种规格,配备聚四氟乙烯或山都平橡胶     

往复式活塞隔膜泵曲轴的动态特性分析

介绍了往复式活塞隔膜泵的结构及工作原理,建立了隔膜泵曲轴有限元模型,利用AN-SYS有限元软件对隔膜泵曲轴进行了应力计算与模态分析,得出最大应力、可能产生断裂的位置及前10阶固有频率.由分析结果知曲轴结构强度安全可靠,工作频率远远低于曲轴的各阶固有频率,所以隔膜泵曲轴因振动引起破坏的可能性很小.研究分析结果为该类产品进一步优化设计提供了理论依据.     

SCR系统隔膜泵瞬态流量特性分析

隔膜泵是Urea-SCR系统中使用最广泛使用的动力单元,其流量稳定性对系统计量精度有较大影响。受隔膜易变形及配流阀参数的影响,隔膜泵瞬时流量易出现较大波动。要避免或减小这种瞬时流量波动现象,必须进行隔膜泵动态特性分析。鉴于隔膜泵结构及材料特点,提出了一种双向FSI模型,经试验验证,该模型可有效预测隔膜泵动态特性。分析结果显示,减小压出阀弹簧刚度、压出阀阀芯质量及压出阀开启压力均可在一定程度上减小隔膜泵瞬时流量波动现象。所采用方法及所得结果可为相近产品的分析提供理论参考。     

液动隔膜泵的研究与开发

长距离、高扬程、高浓度浆体管道输送是适合我国国情的物料输送方式,高压浆体泵是实现这一技术的核心设备.液动隔膜泵是一种新型高压浆体泵.分析了一般隔膜泵的特点.介绍了液动隔膜泵的组成和工作原理,详细介绍了其相关组成部分的设计和开发,并对设计开发中的有关问题进行了研究和探讨.指出液动隔膜泵具有压力高、效率高、无流量脉动、易损件使用寿命长、无混浆、自动化程度高等特点,是理想的适于浆体管道输送的环保节能型产品.     

气动隔膜泵船用市场看好

分析了船用气动隔膜泵的市场情况、气动隔膜泵的关键技术组成，以及将气动隔膜泵推向船用市场的可行性等，对气动隔膜泵制造企业市场开拓有一定借鉴价值。     

基于虚拟样机的隔膜泵动态特性分析

通过Pro-E和ADAMS相结合,建立隔膜泵的虚拟样机模型,对隔膜泵进行运动学和动力学仿真,快速准确地得到了隔膜泵的各种参数,为隔膜泵的计算提供了有效的方法,并为部件的有限元动态分析打下了基础,为进一步开发和参数优化提供理论依据.     

隔膜泵的操作要点及工艺改进研究

隔膜泵是2台往复式双杠双作用的隔膜泵头,是完全对称的构件组合而成的,是利用活塞在缸内进行重复的操作让隔膜室内发生压力变化。文本将针对隔膜泵的工作原理,操作隔膜泵中的要点和工艺进行分析和研究,同时阐述控制系统以及易损件的寿命等。     

金蜂牌中压系列活塞式隔膜泵

金蜂牌ZMB220型、ZMB240型、ZMB460型、ZMB480型活塞式隔膜泵是我国第一个较完整的隔膜泵系列产品,主要技术性能指标已达到国内外同类型产品的水平,均经部级鉴定。1979年至1981年分别荣获部科技成果三等奖和浙江省科技成果二等奖,并评为浙江省优质产品。由该系列产品配套生产的金蜂一40型担架式机动喷雾机1993年获得全国最受用户欢     

活塞隔膜泵与液动隔膜泵的流量脉动分析

浆体输送流量的平稳性直接关系到输送系统的可靠性。该文阐述了活塞隔膜泵与液动隔膜泵的工作原理,着重分析了两种不同泵的流量与时间的关系,讨论了两种泵流量的平稳性问题。指出活塞隔膜泵理论上存在流量脉动,而液动隔膜泵流量均匀,不存在流量脉动。     

固瑞克于第88届美国水展(WEFTEC)上发布最新产品

<正>在2015第88届美国水展(WEFTEC)上,固瑞克流体处理设备部门主力推出了Husky 1050e系列、Solo Tech以及Chem Safe三款新产品。这三款产品分别在性能、优势以及应用范围方面进行了改善。Husky 1050e系列电动隔膜泵固瑞克Husky e系列电动隔膜泵拥有独创的专利技术,可以使泵直接做到背压停机,从而避免在出现     

A system for wear prediction in lubricated sliding contacts

A system of analysis is developed to predict the rate of wear in sliding contacts. The essence of the approach is the proposal that the rate of wear can be predicted only in probabilistic terms. Therefore, the estimation of the probability of wear, which can be regarded as synonymous with the probability of surface asperity contacts, precedes the calculation of the wear rate. Further, recognising the fact that wear takes place within the actual area of contact, it is argued that this area consists of plastic and elastic contacts between asperities which, in turn, have different shear strengths and contribute differently to the wear process. In the case of lubricated contact, a frictional film defect represents the influence of a lubricant on the wear process. Moreover, as in this type of contact the load is supported by both lubricating film and contacting asperities, a special procedure is provided to estimate the load supported by the asperities, because it is only that part of the load which contributes to the wear. The catastrophic form of wear in lubricated contacts, that is termed ‘scuffing’, is also considered, and the probability of scuffing, under a given set of operating conditions, is estimated. The predictive system has been tested and its predictions are compared with available experimental results.     

Histochemical and ultrahistochemical localization of heavy metals in calf organs

Cadmium, zinc, selenium, and copper were administered, singly or in combination, orally or subcutaneously. Experiment I included 32 calves of both sexes; six received Cd (two groups), Zn, Cd, and Zn, and Cd and Se (two groups) and one group was a control. In Experiment II (21 bulls), three were given Cd, Cd, and Cu, and Cd and Zn, respectively, and one group was a control. For light microscopy, in Experiment I the highest amounts of silver granules were present in the samples of liver, small intestine, and vesicular gland of all the exposed groups; in Experiment II the most affected organs were liver, kidney, and small intestine. For electron microscopy, in Experiment I, after administration of Cd and Zn, the highest amounts of granules were seen in the cytoplasm of hepatocytes and cells of the proximal and distal renal tubules and the lowest amounts were found in glandular cells of the pancreas. Administration of Cd and Se resulted in the presence of large numbers of granules in the nuclei and nucleoli of spermatogonies. In Experiment II, ingestion of Cd and Zn in feed led to the appearance of highest amounts of granules in the nucleoli, nuclei, and cytoplasm of cells in testes, kidneys, and pancreas. Following Cd intake, the highest accumulation of granules was observed in the nucleoli of hepatocytes and cells of the proximal and distal renal tubules. Combined Cd and Cu produced the highest number of granules in cells of the proximal and distal renal tubules and in the nucleoli and nuclei of germinal epithelium.     

Immunohistochemical distribution of enkephalin, substance P, and somatostatin in the brainstem of the leopard frog, Rana pipiens

The brainstems of frogs contain many of the neurochemicals that are found in mammals. However, the clustering of nuclei near the ventricles makes it difficult to distinguish individual cell groups. We addressed this problem by combining immunohistochemistry with tract tracing and an analysis of cell morphology to localize neuropeptides within the brainstem of Rana pipiens. We injected a retrograde tracer, Fluoro-Gold, into the spinal cord, and, in the same frog, processed adjacent sections for immunohistochemical location of antibodies to the neuropeptides enkephalin (ENK), substance P (SP), and somatostatin (SOM). SOM+ cells were more widespread than cells containing immunoreactivity (ir) to the other substances. Most reticular nuclei in frog brainstem contained ir to at least one of these chemicals. Cells with SOM ir were found in nucleus (n.) reticularis pontis oralis, n. reticularis magnocellularis, n. reticularis paragigantocellularis, n. reticularis dorsalis, the optic tectum, n. interpeduncularis, and n. solitarius. ENK-containing cell bodies were found in n. reticularis pontis oralis, n. reticularis dorsalis, the nucleus of the solitary tract, and the tectum. The midbrain contained most of the SP+ cells. Six nonreticular nuclei (griseum centrale rhombencephali, n. isthmi, n. profundus mesencephali, n. interpeduncularis, torus semicircularis laminaris, and the tectum) contained ir to one or more of the substances but did not project to the spinal cord. The descending tract of V, and the rubrospinal, reticulospinal, and solitary tracts contained all three peptides as did the n. profundus mesencephali, n. isthmi, and specific tectal layers. Because the distribution of neurochemicals within the frog brainstem is similar to that of amniotes, our results emphasize the large amount of conservation of structure, biochemistry, and possibly function that has occurred in the brainstem, and especially in the phylogenetically old reticular formation.     

双列调心凹面滚子轴承接触载荷分析

在考虑滚子与套圈、滚子与保持架以及保持架与引导套圈作用力的条件下,建立双列调心凹面滚子轴承动力学模型.以某双列调心凹面滚子轴承为研究对象,与静力学分析模型滚子最大接触载荷计算结果对比,验证了模型的正确性.并分析了工况条件(轴向载荷、径向载荷、倾覆力矩、转速)和结构参数(滚子数量、滚子长度、径向游隙)对滚子最大接触载荷的...     

Localization of sarcoglycan, neuronal nitric oxide synthase, beta-dystroglycan, and dystrophin molecules in normal skeletal myofiber: triple immunogold labeling electron microscopy.

In order to investigate the mode of existence of the sarcoglycan complex, neuronal nitric oxide synthase (nNOS), beta-dystroglycan, and dystrophin in the normal skeletal myofiber, we examined the ultrastructural localization and mutual spatial relationship of nNOS, beta-dystroglycan, dystrophin, and the individual components of the sarcoglycan complex by using triple immunogold labeling electron microscopy. Each molecule of alpha-, beta-, gamma- and delta-sarcoglycans is located intracellularly or extracellularly near the muscle plasma membrane mostly in accordance with the sarcoglycan antigenic sites against which the antibodies were generated. The association of different two and/or three sarcoglycan molecules out of alpha-, beta-, gamma- and delta-sarcoglycan molecules was frequently observed. Each molecule of nNOS, beta-dystroglycan, and dystrophin was ultrastructurally noted along the cell surface of normal skeletal myofibers. Moreover, the close relation of a sarcoglycan molecule with beta-dystroglycan and dystrophin, and the association of nNOS with dystrophin were also confirmed ultrastructurally. Thus, this study demonstrated that the constituting molecules of the sarcoglycan complex, nNOS, beta-dystroglycan, and dystrophin existed in the form of a cluster at the normal muscle plasma membrane. The association of nNOS with dystrophin and its associated glycoproteins may form a macromolecular signaling complex at the muscle plasma membrane.     

浅析空调净化系统的日常维护

在查看国内外文献、读书和实践的基础上,对空调净化系统各个部分的清洁消毒和维护进行讨论,包括高、中、初效过滤器的清洁更换、管道的清洁、仪表的校验、阀门的检查以及整个系统的消毒灭菌等,着重阐述其清洁消毒和维护的重要性,期望能够得到企业的重视。     

网格曲面上的样条曲线阵列

提出一种流形网格曲面上曲线阵列复制方法,达到曲线重用与再设计的目的。网格曲面上的曲线用测地B样条表示,使对曲线的操作可以转换为对曲线控制顶点的操作;引入离散指数映射理论将给定的源曲线控制顶点映射到切空间,获得它们的法坐标,按照曲线阵列前后控制顶点法坐标保持不变的原则,建立曲线阵列前后控制顶点的对应关系,实现曲线的有规律多重复制。法坐标很好地保持了控制顶点之间的测地距离和相对位置关系,因而也保证了曲线阵列重用过程中的形状保持性。将曲线阵列时的位置与形状分开处理,使曲线生成仅与其所在的局部区域有关而与曲面的整体大小无关,既便于保证曲线的形状保持性,也减少了计算量。试验结果表明,所介绍方法健壮、有效,能满足曲面上曲线的交互设计要求。     

Effects of polydatin on the proliferation,migration, and invasion of ovarian cancer

To investigate the effects of polydatin on the proliferation, migration, and invasion of ovarian cancer, the change of proliferative ability, migration ability, and invasive ability of human ovarian cancer cell OVCAR-3, A2780, and HO-8910 was detected by using polydatin and up-regulating PI3K. The anticancer activity and mechanism of polydatin in ovarian cancer were analyzed. Polydatin could effectively inhibit the proliferation, migration, and invasion of OVCAR-3, A2780, and HO-8910, and inhibit the expression of PI3K protein. After the expression level of PI3K protein was up-regulated, the inhibitory effect of polydatin on the proliferative ability, migration ability, and invasive ability of OVCAR-3, A2780, and HO-8910 significantly decreased, suggesting that PI3K was the target of polydatin. Therefore, we concluded that polydatin could inhibit the proliferation, migration, and invasion of ovarian cancer cells by inhibiting the expression of PI3K protein, which provides an experimental basis for polydatin in the treatment of ovarian cancer.     

Future directions of fundamental research in additive tribochemistry

This paper reviews briefly the present state of fundamental research, in tribochemistry of load-carrying additives, including oiliness agents, organolsulphur, organochlorine, organophosphorus, organic borates and organometallic compounds. The emphasis is on the weak areas of investigation. It is revealed that the least understood mechanisms, such as the effect of additives on fretting wear, additive-material compatibility, the efficacy of antifatigue additives and the action of water-based fluid additives in metalworking, are the concern of overlapping spheres of learning. A cooperative effort by chemists, metallurgists and mechanical engineers would help overcome the difficulties posed by problems in areas beyond individual expertises. Some research projects for the future are also suggested.     

Sperm ultrastructure and spermatogenesis in the lizard, <i>Tropidurus itambere</i>

Spermatogenesis, with emphasis on spermiogenesis, is described for the lizard, Tropidurus itambere, using light microscopy, phase contrast and epifluorescence, as well as scanning and transmission electron microscopy. Cellular differentiation involves events of chromatin condensation, nuclear elongation and the formation of structural complexes, such as the acrosomal and axonemal ones. Other new characteristics, exclusive for this species, include various aspects of the subacrosomal granule, the insertion of the proacrosomal vesicle and the development of these structures to participate in the acrosomal complex. Radial projections occur just above the nuclear shoulders, which have been recognized already from the beginning of cellular elongation. The development of the midpiece, the dense bodies, formation of the flagellum and elimination of residual cytoplasm result in the final characterization of the mature spermatozoon. Comparisons between Tropiduridae and other lizard families are made.