采油螺杆泵液压马达驱动装置

介绍了采油螺杆泵液压马达驱动装置的工作原理,分析了其特性和优势。重点阐述了液压马达驱动系统的结构组成和正转驱动及反转制动的过程。和常规螺杆泵驱动装置相比,螺杆泵液压马达驱动装置具有无级调速、自我保护能力强、技术附加值高等优点。     

太阳能集热装置随动跟踪液压系统设计

太阳能以其安全、清洁、无污染、储量丰富等优点逐渐受到人们的关注。针对其密度低、光照方向变化等特点,发明了跟踪装置以提高太阳能的利用率。为了提高跟踪装置精度,降低制造成本,对现有视日运动轨迹式跟踪装置提出了改进方案。设计了一种新型跟踪装置,采用液压马达驱动液压绞车带动反射镜转动跟随太阳,避免了采用双液压缸驱动时所需要的复杂轨迹规划。利用单片机控制实现装置的自动运行,设计了完整的液压驱动方案,详细描述了其工作原理,通过MATLAB仿真验证了跟踪装置液压系统的可行性。     

无避让立体停车装置液压系统的动态特性

以某新型无避让液压立体停车装置为研究对象,阐述其液压驱动系统工作原理,液压驱动系统的性能直接影响装置运行的安全性与可靠性,为保证装备运行平稳,提高装备安全可靠性,需要对其液压系统的动态特性进行研究。运用AMESim建立液压驱动系统模型,对系统的动态特性进行了仿真研究,分析了停车装置运行时稳定可靠性、抗冲击性能及升降过程中的同步性,通过优化系统参数匹配,使系统获得良好动态特性,保证停车装置安全、可靠,平稳运行。     

浅析筑路机械冷却装置液压驱动系统的设计

在筑路机械设备中,冷却装置很重要。液压驱动系统是冷却系统的重要组成部分,关系到冷却装置功能的发挥。基于这种认识,本文对筑路机械冷却装置液压驱动系统的设计需求展开了分析,并从系统结构、发动机冷却、液压传动系统冷却和电气系统等方面对系统设计问题进行了探究。     

流动的逻辑之静液压驱动装置的基本液压回路构成

静液压驱动装置构成了车辆与行走机械中介于发动机和车轮、履带等行走装置之间的传动环节,其输入端元件是液压泵,输出端元件或称执行元件是能够连续旋转并克服行走装置转矩负荷的液压马达。液压泵和液压马达之间的连接回路有开式和闭式回路两种系统,笔者介绍的静液压驱动装置主要采用的是闭式回路液压系统,这与大多数工业固定设备和以液压挖掘机为代表的一部分行走机械采用的开式液压系统有所不同。通过对现代液压技术中的开式和闭式两种回路系统的分析比较,将有助于读者理解闭式回路的主要特点以及静液压驱动装置需要采用闭式回路及其变型系统的原因。     

冷却风扇及其液压驱动装置的特性匹配研究

液压驱动冷却风扇因其技术优势已被越来越广泛地应用在车辆冷却系统中,通过对冷却风扇及其液压驱动装置的特性进行分析,推导出冷却风扇与液压驱动装置的参数匹配方法,并用实例对此方法进行了进一步验证。     

曲臂式高空作业车液压系统设计及研究

液压技术的快速发展给我国高空作业车的开发、研制奠定了技术基础。通过对高空作业车的整体设计要求,完成了对高空作业车主要装置和与其对应的液压系统的设计。曲臂式高空作业车由底盘、动力系统、液压系统、扩桥装置、转向装置、回转装置、变幅装置、伸缩臂装置、调平装置、作业斗摆动装置和电控系统等构成。根据控制系统需要控制的执行元件较多、多个执行元件需要比例控制的特点,系统采用了内置比例流量阀的插装阀块的控制形式实现对工作装置多任务协调控制的控制要求。作为独立驱动车辆,行走驱动系统的设计是本车的关键技术之一。为了实现行走系统的远程调速性能以及实现节能高效、稳定的性能,采用了变量泵控双速马达的液压闭式回路作为行走驱动系统的回路形式。依据液压系统的设计原理,详细探讨了曲臂式高空作业车液压系统的设计方法,为各种类型高空作业车液压系统的设计提供了一个完善的设计方法和平台。     

盾构刀盘驱动模拟装置液压系统设计与研究

论述了一种盾构刀盘驱动模拟装置液压系统工作原理,从变量泵、电机及液压马达选型、发热计算等方面对其液压系统进行了设计与研究,并根据实验需求,按照等比缩放原则,设计了模拟刀盘惯性负载的惯性轮。该模拟装置,能够为进行盾构刀盘驱动液压控制系统的研究提供可靠的实验平台。     

快关蝶阀液压驱动装置

介绍了快关蝶阀液压驱动装置液压控制及电气控制部分的系列化设计。     

一种液压驱动的抬升装置

研制了一种液压驱动的抬升装置，它可以将物品抬升到一定高度，再将物品倾卸出来，着重介绍了这种装置的液压系统以及装置的操作。     

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.     

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.     

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。     

可展开固体反射面机构设计及运动学分析

针对传统固体反射面机构主反射面型面精度和收拢率较低的问题,设计了一种可展开固体反射面机构。首先,提出4种固体反射面机构可展单元构型并对其机构自由度进行分析,对比分析构型方案优缺点确定构型方案4作为可展单元基础构型,并对其结构和展开原理进行详细设计。通过D-H坐标变换建立该机构可展单元的运动学模型,根据几何约束条件建立机构位置矢量方程,利用向量封闭投影法解出各回转角间的关系,结合MATLAB软件编程对机构的位置、速度和加速度进行分析。应用ADAMS软件建立机构仿真模型,验证了机构运动学分析的正确性。最后根据机构中回转角的限制条件和结构尺寸关系,分析回转角和结构尺寸对可展开固体反射面机构收拢率的影响,确定2.2m可展开固体反射面机构的回转角和旋转角分别为78°和30°,中心圆盘半径、铰支座一孔纵向尺寸、切换连杆横向尺寸、纵向尺寸分别为245,8,40,18mm,收拢率为0.326,从而为可展开固体反射面机构的设计提供参考。     

Review on microbial metabolomics of probiotics and pathogens: Methodologies and applications

In recent years, microbial metabolomics, a new field that has attracted wide attention, provides a map of metabolic pathways and clarifies the interaction mechanism between microorganisms and hosts. Many microorganisms are found in the human intestine, oral cavity, vagina, etc. Probiotics could maintain the good health of the host, while pathogens and an imbalance of bacterial flora lead to a series of diseases of the body and mind. Metabolomics is a science for qualitative and quantitative analysis of all metabolites in an organism or biological system, which could provide key information to understand the related metabolic pathways and associated changes. This approach analyzes the final products of cellular regulatory processes, the level of which can be regarded as the ultimate response of the biological system to genetic or environmental changes. Microbial metabolomics has been widely used in different research fields, such as microbial phenotypic classification, mutant screening, metabolic pathways, microbial metabolic engineering, fermentation engineering monitoring and optimization, microbial environmental pollution, and so on. However, there are only a few reviews on microbial metabolomics of probiotics and pathogens. This review summarizes the main methodologies, including sample preparation, identification of metabolites, data processing, and analysis. Recent applications in microbial metabolomics of probiotics and pathogens are also described. This paper first summarized the research progress and application of microbial metabolomics from two aspects: probiotics and pathogenic bacteria. Probiotics and pathogenic bacteria do not exist independently most of the time; hence, these were reviewed in the research field of coexistence of probiotics and pathogenic bacteria, which was subdivided into important microbial research fields closely related to human health, including the human gut, oral cavity, food, and nutrition-related microorganisms. Then, the main problems and trends associated with microbial metabolomics are discussed.     

生物轻质高强结构及其在吸能结构中的仿生应用

在长期进化过程中，自然界中的多种动物、植物形成了独特的轻质、高强结构，以此来抵抗外界的复杂冲击载荷，保护自身完整，满足生存需要。生物轻质高强结构的优越性，启发了科研和工程人员采用结构仿生学的方法来对管状和板状两大类吸能结构进行设计优化和改进。对竹子、茎秆/树干、羽轴、骨骼四类管状生物结构和甲虫鞘翅、贝壳、柚子皮、龟壳四类板状生物结构进行综述，阐述了分层、多孔、螺旋、中空等多种结构与轻质高强特性之间的关系。在此基础上，对比和分析了相应的结构元素在单胞管、多胞管、嵌套管、波纹管等管状吸能结构和蜂窝夹芯板、复合材料板、混合结构板等板状吸能机构中起到的作用。进一步对当前仿生吸能领域存在的结构复杂、质量大、缺乏普适性的机理和过渡“桥梁”等问题做出了分析；最后对仿生吸能技术的形式简单化、结构轻量化、理论通用化、“形神兼备”化发展趋势做出展望。     

基于FLUENT的液体动静压轴承的动态特性分析

应用计算流体力学软件FLUENT对超高速磨削用五腔动静压轴承进行动态特性研究,得到动静压轴承内部压力场和温度场分布;计算轴承的承载力、温度、刚度、阻尼等动态参数,分析这些动态参数与偏心率以及转速之间的关系。结果表明:在保持供油压力和轴承偏心率不变的情况下,随着转速的提高,油温上升,轴承承载力及偏位角不断增大;在保持供油压力和主轴转速不变的情况下,随着偏心率的增大,轴承流量有所减少,轴承的承载能力不断增大,偏位角基本保持不变。     

海洋环境下典型金属材料腐蚀与磨损研究进展

海洋环境下金属材料的腐蚀与磨损及其复杂的交互作用是影响海洋装备可靠性和工作效率的关键因素。在概述海洋环境下金属材料腐蚀和磨损的现象及问题的基础上,分析海洋环境下典型金属腐蚀与磨损的交互作用研究进展及发展趋势,并对不锈钢、钛合金与铝合金等主要海洋环境用金属材料在不同介质下的腐蚀与磨损问题进行探讨,重点阐述海洋环境下金属腐蚀与磨损中相互促进的正交互作用和相互抑制的负交互作用机制以及它们之间的相互影响、过渡和转换等方面的研究进展。在腐蚀与磨损正、负交互作用转变的过程中,从微观角度讲,奥氏体和马氏体相的多次转变是主要影响因素;而从宏观角度看,材料的摩擦因数、载荷、运动形式等动摩擦因素和Cl-浓度、pH值、频率及外加电位等电化学因素是两类主要影响因素。对比分析多种腐蚀与磨损交互作用的计算模型,阐述利用表面技术改善金属材料防腐耐磨性能的研究进展,提出金属材料腐蚀与磨损的负交互作用机制、微生物对腐蚀与磨损交互作用的影响机制、微动磨损与腐蚀的交互作用研究以及腐蚀与磨损交互作用量的准确量化是未来的研究重点。     

热喷涂宽温域耐磨自润滑涂层研究现状与展望

在航空、航天、冶金、电力、石化、矿采等领域,零件高温摩擦磨损特性是影响装备寿命的重要因素,在关重零部件表面设计制备宽温域耐磨自润滑涂层是装备零件强化改性和再制造修复的重要手段。首先阐述了宽温域耐磨自润滑涂层设计中过渡层、基础相、增强相的材料选择依据;其次针对单一固体润滑剂适用温度范围窄的问题,梳理了从低温润滑剂发生氧化反应原位生成高温润滑剂,低温润滑剂与高温润滑剂长时协同作用,添加抑制剂减缓润滑相的损耗退化等三种宽温域耐磨自润滑涂层材料设计方法;而后总结了宽温域耐磨自润滑涂层的制备工艺,分析了不同喷涂工艺的技术特点和涂层制备实例,介绍了宽温域耐磨自润滑涂层在军事装备和工业设备上的典型应用;最后在此基础上对宽温域耐磨自润滑涂层的未来发展方向进行了展望。