关键词： 柴油机   调整   使用   保养  

摘要： 近年来,随着科技的飞速发展,农业的机械化水平也是日新月异。随之而来的便是广大农业生产者对农业机械知识的渴求也是越加迫切。135型系列的柴油机是我国自行设计和制造的系列化的内燃机产品,经过多种配套广泛使用于工农业生产中,作通用动力装置。

关键词： 连续血流动力学监测   机械通气   临床应用  

摘要： 目的：对接受机械通气治疗的患者应用连续血流动力学监测技术的临床相关性进行分析研究。方法：选取自2012年10月～2014年4月间我院接受机械通气治疗的患者共26例作为研究对象，对其进行脉搏轮廓动脉压波形分析法（ PICCO）监测，心排血指数、心排血量、外周血管阻力和每搏量进行监测。结果：患者在接受机械通气治疗后，其心排血指数、心排血量、外周血管阻力和每搏量与治疗前相比有明显差异，p＜0．05。结论：PICCO监测方法可以作为机械通气治疗中重要监测指标，对于患者临床治疗方法的制定具有指导作用。

关键词： 工程机械   混合动力   关键技术   节能减排  

摘要： 随着社会经济不断发展,促进了机械制造行业的发展。为了使工程机械在运行中减少能源消耗,因此要加强混合动力关键技术,使机械的各项动力参数符合环保理念。本文将分析工程机械中混合动力关键技术,并分析其节能减排的效果。

关键词： 机械可靠性   机械零部件   东北大学   动力学   秦皇岛   设计师   直列式发动机   机械产品  

摘要： 缝纫机、汽车变档机制、车用直列式发动机、飞机的星形发动机、飞机螺旋桨同步射击器、车等速万向节等等这些动态机械无时无刻不与我们的生活亲密接触。然而，随着现代化工业技术的飞速发展，机械产品日趋复杂化、大型化、高参数化，产品故障机率随之增多。我国机械产品的可靠性设计水平与国际先进水平相比还有相当大的差距，这已成为制约我国机械工业迅速发展的瓶颈。

关键词： 瓣下结构   人工瓣   二尖瓣置换术   血流动力学   多普勒超声  

摘要： 目的明确瓣下结构不同保留方式对***二尖瓣机械瓣下游血流动力学的影响.方法将入选的39名患者依据瓣下结构保留方式分为未保留瓣下结构组、保留后瓣组和保留全瓣组.多普勒超声心动图仪检测常规多普勒指标(平均跨瓣压差PGmean,跨瓣流量Qmv),心功能指标(左室射血分数LVEF),流场均匀性指标(二尖瓣峰值流速Vmax,峰值流速最大差值ΔVmax),然后应用计算机图像分析技术计算湍流剪应力(TSS)和相对扰动强度(Irel).结果保留瓣下结构可在一定程度上增加跨瓣血流的扰动性,使***机械瓣下游流场均匀性变差,TSS和Irel增大(P<0.05).结论保留后瓣瓣下结构可改善术后心功能,对跨瓣血流影响较保留全瓣轻,适合大多数二尖瓣置换术患者.

关键词： 林业   小型动力机械   回顾   现状  

摘要： 林业小型动力机械是生产批量最大的林业机械产品,在林业生产中发挥着重要作用。介绍了林业小型动力机械所包含的产品类型、相关的协会和学会等组织机构及其在国内发展的历史和生产现状;指出了我国产品质量与先进国家之间的差距,以及科研和人才培养等方面存在的不足。

关键词： face seal   gap   tapering   undulation   pressure distribution  

摘要： This paper presents numerical and analytical techniques for calculating the hydrodynamic characteristics of mechanical face seals with gaps of complex forms that feature tapering and undulation. The numerical technique is developed using the finite volume method and takes into account inertial forces. With the tapering and undulation parameters of the clearance taken equal to zero, the analytical expressions obtained for the working fluid leakage through the gap of complex form are reduced to well-known relations. The techniques developed are applicable to both hydrodynamic and contact face seals.

关键词： titanium hydride   mechanical vibrations   stress   hardness   ductility   compressive strength  

摘要： The effect of mechanical vibrations on the structure formation and mechanical properties of compacts during electron beam sintering is investigated. Using optical microscopy, continuous indentation, and X-ray diffraction, it was established that imposing mechanical vibrations decreases the average titanium grain size by a factor of 1.5-2 and induces residual compressive stresses in the sintered titanium compact. Due to the stresses, greater density, and smaller grains, the ductility and compressive strength of the compacts sintered under mechanical vibrations are higher than those of the compacts sintered in conventional way.

关键词： Molecular dynamics   Carbon nitride   Mechanical   Thermal conductivity  

摘要： Graphitic carbon nitride (g-C3N4) nanosheets are among 2D attractive materials due to presenting unusual physicochemical properties. Nevertheless, no adequate information exists about their mechanical and thermal properties. Therefore, we used classical molecular dynamics simulations to explore the thermal conductivity and mechanical response of two main structures of single-layer triazine-based g-C3N4 films. By performing uniaxial tensile modeling, we found remarkable elastic modulus of 320 and 210 GPa for two different structures of g-C3N4 sheets. Using equilibrium molecular dynamics simulations, the thermal conductivity of free-standing g-C3N4 structures were also predicted to be around 7.6 W/mK and 3.5 W/mK. Our study suggests the g-C3N4 films as exciting candidate for reinforcement of polymeric materials mechanical properties. (C) 2015 Elsevier B.V. All rights reserved.

关键词： CPL   Kinetics   Mechanism   Polymerization   Ionic strength   Rate constant   Activation parameters  

摘要： This study investigated on kinetics of oxidation of captopril by QDC was studied spectrophotometically in acidic medium along with its mechanistic pathway. Such studies are greatly helpful in gaining an insight into the interaction of metal ions through the study of the mechanistic pathway of CPL in redox reactions. The oxidative product of captopril was found to be captopril disulfide was separated, and identified by FT-IR. A suitable free radical mechanism was proposed. The reaction exhibited first-order kinetics with respect to [oxidant] and fractional order in CPL. Consequently, the interaction between the complex species and CPL is supported kinetic orders of reaction by spectrophotometric verification, positive entropy of activation and the first-order rate constant increased with the increase in the dielectric constant and increase ionic strength of the medium. The reaction constants involved in the mechanism were computed and the overall activation parameters were evaluated which lend support to the proposed mechanism. (C) 2014 Elsevier B.V. All rights reserved.