关键词： 安全操作规程   安全启动   动力机械   安全管理人员   农业生产   农机事故   宣传教育   安全生产  

摘要： 在农业生产中，由于不按照农业安全操作规程去作业而造成的农机事故约占事故总数的60％以上。这些事故的发生，给生产、经济带来不应有的损失，甚至造成伤亡。安全管理人员必须首先严格遵守有关安全的操作规程，并进行广泛的宣传教育，加强安全管理，确保安全生产。在整个农业生产事故中，由于动力机械的不正确操作造成的事故率较高。

关键词： 动力机械设备   故障诊断   发展趋势  

摘要： 介绍了动力机械设备故障诊断技术,分析了制约其发展的主要因素,阐述了动力机械设备故障诊断技术的发展趋势。

关键词： 机械动力学   学术会议   征文范围   中国   专业委员会   动力学理论   机床动力学   工程学会  

摘要： 由中国振动工程学会机械动力学专业委员会主办的＂2011中国机械动力学学术会议＂将于2011年7月29—31日在杭州召开。征文范围：机械动力学理论与方法;机床动力学;动态测试与信号分析;机械系统故障诊断;

关键词： Inflow cannula   Mechanical circulatory support   Pressure loss   Bridge to decision  

摘要： Recent progress in the development of implantable rotary blood pumps realized long-term mechanical circulatory support (MCS) for bridge to transplant, bridge to recovery, or a destination therapy. Meanwhile, a short-term MCS system is becoming necessary for bridge to decision. We developed a novel inflow cannula for the short-term MCS system, which gives sufficient bypass flow with minimal invasion at insertion, and evaluated its hydrodynamic characteristics. The novel inflow cannula, named the Lantern cannula, is made of elastic silicone reinforced with metal wires. The cannula tip has six slits on the side. This cannula tip can be extended to the axial direction by using an introducer and can be reduced in diameter, and the Lantern cannula enables easy insertion into the left ventricle apex with minimal invasion. The sufficient bypass flow rate can be obtained due to low pressure loss. Moreover, this Lantern shape also resists suction complication around the cannula tip. The pressure loss through the Lantern cannula was measured using a mock circulation and compared with two commercially available venous cannulae (Sarns4882, Terumo, Tokyo, Japan and Stockert V122-28, Sorin Group, Tokyo, Japan), which have almost same diameter as the Lantern cannula. Moreover, the flow patterns around the cannula tip were numerically analyzed by computational fluid dynamics (CFD). Acute animal experiment was also performed to confirm the practical effectiveness of the Lantern cannula. The pressure loss of the Lantern cannula was the lowest compared with those of the commercially available venous cannulae in in vitro experiment. CFD analysis results demonstrated that the Lantern cannula has low pressure loss because of wide inflow orifice area and a bell mouth, which were formed via Lantern shape. The highest bypass flow was obtained in the Lantern cannula because of the low pressure loss under pulsatile condition in in vivo experiments. The Lantern cannula demonstrated superior hyd

关键词： biosensors   DNA detection   electrochemistry   electron transfer   ferrocene   peptide nucleic acids  

摘要： N-Terminally ferrocenylated and C-terminally gold-surface-grafted peptide nucleic acid (PNA) strands were exploited as unique tools for the electrochemical investigation of the strand dynamics of short PNA(.DNA) duplexes. On the basis of the quantitative analysis of the kinetics and the diffusional characteristics of the electron-transfer process, a nanoscopic view of the Fc-PNA(.DNA) surface dynamics was obtained. Loosely packed, surface-confined Fc-PNA single strands were found to render the charge-transfer process of the tethered Fc moiety diffusion-limited, whereas surfaces modified with *** duplexes exhibited a charge-transfer process with characteristics between the two extremes of diffusion and surface limitation. The interplay between the inherent strand elasticity and effects exerted by the electric field are supposed to dictate the probability of a sufficient approach of the Fc head group to the electrode surface, as reflected in the measured values of the electron-transfer rate constant, k(0). An in-depth understanding of the dynamics of surface-bound PNA and *** strands is of utmost importance for the development of DNA biosensors using (Fc-)PNA recognition layers.

关键词： Acrylonitrile-butadiene rubber (NBR) composites   Bentonite   Rheological behavior   Mechanical properties   Vulcanization kinetics  

摘要： The effect of the incorporation of bentonite (BT) untreated and treated with octadecylamine on the rheological behavior and vulcanization kinetics of NBR was investigated. Mechanical properties were also evaluated. Decreases in the optimum cure time (t(90)) and in the scorch time (t(S2)) and a notorious improvement in mechanical properties were found when treated BT was employed. From the vulcanization kinetics analysis, we can infer that the curing rate is superior for the treated BT composites, while the reaction orders point out the dependency of the vulcanization reaction on the initial reactants if compared to the catalytic effect of the reaction products.

关键词： MOLECULAR dynamics   PLUTONIUM   METALS -- Mechanical properties   GALLIUM (Metal)   HELIUM   IRRADIATION   ELASTICITY   POISSON'S ratio  

摘要： The effects of self-irradiation on the mechanical properties of Ga-stabilized delta-Pu are investigated by means of classical molecular dynamics simulations using a modified embedded-atom method interatomic potential. The impact that variations in the concentration of Ga, He, and vacancies have on the elastic properties (Young's modulus, Poisson's ratio, shear modulus, and bulk modulus) of Ga-stabilized delta-Pu is determined through CMD simulation. The effect that variations in these concentrations have on plastic flow is assessed at strain rates of 10(7)-10(10) s(-1). Comparison is made to experimental data. (C) 2011 Elsevier B.V. All rights reserved.

关键词： MOLECULAR dynamics   POLYMER networks   MATERIALS -- Mechanical properties   ALGORITHMS   EPOXY compounds   GLASS transition temperature   OLIGOMERS  

摘要： The mechanical properties of Epon-862 crosslinked with curing agent DETDA were simulated using a molecular dynamics code named GPIUTMD fully developed on multi graphical processing units. A new algorithm was proposed to simulate the cross-linking process during the chemical interaction of epoxy with the curing agent without changing the bond data. The models were created by densely packing preconstructed oligomers of different composition and compact them into the periodic simulation box. The properties of interest predicted by the molecular dynamics method were density, glass transition temperature and bulk modulus and found to be in good agreement with available data in the literature. Also, a study on the optimal ratio of resin to cure agent was carried out, and the results showed that, with a 3.6 mix mass ratio, the composite is in its strongest mechanical and structural state.

关键词： ammonia   atom-molecule reactions   excited states   ground states   hydrogen neutral atoms   potential energy surfaces   reaction rate constants   vibrational states  

摘要： On a recent analytical potential energy surface developed by two of the authors, an exhaustive kinetics study, using variational transition state theory with multidimensional tunneling effect, and dynamics study, using both quasi-classical trajectory and full-dimensional quantum scattering methods, was carried out to understand the reactivity of the NH3 + H -> NH2 + H-2 gas-phase reaction. Initial state-selected time-dependent wave packet calculations using a full-dimensional model were performed, where the total reaction probabilities were calculated for the initial ground vibrational state and for four excited vibrational states of ammonia. Thermal rate constants were calculated for the temperature range 200-2000 K using the three methods and compared with available experimental data. We found that (a) the total reaction probabilities are very small, (b) the symmetric and asymmetric N-H stretch excitations enhance the reactivity, (c) the quantum-mechanical calculated thermal rate constants are about one order of magnitude smaller than the transition state theory results, which reproduce the experimental evidence, and (d) quasi-classical trajectory calculations, which were performed with the main goal of analyzing the influence of the zero-point energy problem on the final dynamics results, reproduce the quantum scattering calculations on the same surface. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3605242]

关键词： 机械系统   混合动力   控制问题   动力学   圣彼得堡   研究成果   论文集   非线性  

摘要： 本书是一本会议论文集，基于2008年在圣彼得堡举行的第6届欧洲非线性动力学会议内容整理而成。书中包含了许多跨国及跨学科领域合作的研究成果，代表了混合机械系统领域21世纪最前沿的研究水平。书中通过不同状态空间域的各种模型与方法，帮助读者更容易理解一大类混合动力机械系统的动力学与控制问题。