关键词： 规范   便携的   振动测量   林业设备   SPECIFICATIONS   SPECIFICATION   PORTABLE   VIBRATION MEASUREMENT   FOREST EQUIPMENT   FORESTRY EQUIPMENT  

标准号: GB/T 5395-2014

摘要： 本标准规定了以内燃机为动力的便携式手持操作林业和园林机械手把振动的测定方法。本标准适用于油锯(高把油锯除外)、割灌机、割草机、杆式动力修枝锯、绿篱修剪机和吹叶机/吸叶机等便携式林业和园林机械。本标准规定的测定方法虽然是在模拟实际操作机器情况下获得的数据,但这些数据与真实结果非常接近,代表了机器实际工作状况时的特性。

关键词： 农业机械   安全   割草机   剪草机   灌木   收获机械   AGRICULTURAL MACHINERY   AGRICULTURAL MACHINES   SECURITY   SAFETY   GRASS MOWERS   MOWERS   LAWN TRIMMERS   GRASS SHEARS   LAWN MOVERS   LAWN-MOWERS   SHRUBS   HARVEST EQUIPMENT   HARVESTING EQUIPMENT   HARVESTING MACHINES  

标准号: GB 19725.1-2014

摘要： GB 19725的本部分规定了以内燃机为动力并将机械动力传递至切割附件的便携式侧挂动力割灌机和割草机(以下简称整机)的设计、结构和使用方面的安全要求及其试验方法。本部分提出了消除或减少在使用割灌机和割草机过程中所产生的各种危害的方法,规定了由生产厂商提供的有关安全操作方面资料的要求。本部分涉及了在正常使用以及合理的、生产厂家可预见的误用整机时所有与整机相关的严重危险、危险情况及严重危害事件。本部分不适用于装备有非整体金属切割附件的整机,例如甩链或甩刀刀片。本部分适用于在其颁布实施后生产的便携式侧挂动力割灌机和割草机。

关键词： 多体动力学   动力学建模   数值仿真   轮式悬架   刚-柔并联机械手  

摘要： 考虑到移动串联机械手不能很好地满足高速、大负载工况下准确作业的要求,提出了轮式悬架柔性移动并联机械手这一新的构型,并对其进行了动力学性能研究。基于多柔性体动力学,在笛卡尔坐标下构建了系统动力学模型,建模方法具有通用性与完备性。在此基础上,分别针对串联、并联、刚性、柔性四类移动机械手的动力学模型进行了数值仿真,并对仿真结果进行了比较、分析,验证了建模方法的正确性并佐证了新构型移动机械手的动力学性能特点,提出了提高柔性并联机械手的工作速度、刚度和工作精度的技术方法,为后续控制算法的构建提供了理论基础。

关键词： Energy harvesting   Bistable oscillator   Wideband   Self-powered   Nonlinear   Mechanical switches  

摘要： Energy harvesting is considered as one of the most promising solution for the power supply of autonomous sensor systems. Two main properties are required: self-powered ability and wideband operation. This article proposes a new self-powered bistable generator which is composed of three parts: the self-powered OSECE (Optimized Synchronous Electric Charge Extraction) circuit, the BSM (buckledspring-mass) oscillator and two stoppers. The combination of the BSM oscillator and the stoppers allows wideband harvesting capability and the self-powered OSECE circuit with mechanical switches ensures high harvested power and autonomous features. A model of this novel generator is detailed and experimentally validated. As an incremental innovation, better performance is obtained for this new generator compared with the original BSM generator with the standard circuit (without stoppers and mechanical switches). Discussions and optimizations are performed to find the optimal parameters and fully investigate the performance of the proposed generator. It shows that introducing the stoppers and the self-powered OSECE circuit using mechanical switches can substantially enhance the harvested power with moderate additional complexity. (C) 2014 Elsevier B.V. All rights reserved.

关键词： 国家自然科学基金委员会   混合动力驱动系统   工程学科   协同优化设计   混合驱动系统   最优控制理论   随机动态规划   控制设计  

摘要： 项目负责人：邹渊（E-mail：zouyuan@***）依托单位：北京理工大学项目批准号：509050151．项目简介以双电机独立驱动的混合动力履带车辆为研究对象和应用背景，从优化控制理论角度对履带车辆混合动力动态特点及系统控制设计开展研究。重点研究履带车辆混合动力驱动系统电耦合瞬态模型、最优化控制设计方法以及混合驱动系统参数与控制协同优化设计。研究表明，最优控制理论能够有效指导混合动力驱动系统控制优化设计。其中确定性动态规划获得理论的控制最优解可以作为系统控制学习和标定的样本。随机动态规划引入功率需求的随机性，通过策略迭代获得最优控制律具备多工况适应性。庞特里亚金极值原理从系统解析角度来获得最优控制的必要条件，该方法能降低计算量。混合驱动系统参数与控制协同优化能揭示系统动/静态特性与控制的耦合规律。为混合驱动系集成及控制设计开辟新的理论途径与参考。

关键词： 南京工业大学   实验教学   机械基础   动力工程   综合实验平台   教学示范中心   实验技术人员   实验教师  

摘要： 南京工业大学机械与动力工程实验教学中心由机械基础、过程装备与控制工程、机械工程及自动化等6个综合实验平台构成，含20个实验室，是江苏省实验教学示范中心。机械与动力工程实验教学中心现有专职实验教师26人，兼职实验教师15人，实验技术人员6人，其中教授20人，副教授、高工19人，具有博士学位的19人。

关键词： flavonoid   MMP-9   interaction mechanism   hybrid QM/MM   molecular dynamics simulation  

摘要： Many experimental studies have found that flavonoids can inhibit the activities of matrix metalloproteinases (MMPs), but the relevant mechanisms are still unclear. In this paper, the interaction mechanisms of MMP-9 with its five flavonoid inhibitors are investigated using a combination of molecular docking, hybrid quantum mechanical and molecular mechanical (QM/MM) calculations, and molecular dynamics simulations. The molecular dynamics simulation results show a good linear correlation between the calculated binding free energies of QM/MM-Poisson-Boltzmann surface area (PBSA) and the experimental -log(EC50) regarding the studied five flavonoids on MMP-9 inhibition in explicit solvent. It is found that compared with the MM-PBSA method, the QM/MM-PBSA method can obviously improve the accuracy for the calculated binding free energies. The predicted binding modes of the five flavonoid-MMP-9 complexes reveal that the different hydrogen bond networks can form besides producing the Zn-O coordination bonds, which can reasonably explain previous experimental results. The agreement between our calculated results and the previous experimental facts indicates that the force field parameters used here are effective and reliable for investigating the systems of flavonoid-MMP-9 interactions, and thus, these simulations and analyses could be reproduced for the other related systems involving protein-ligand interactions. This paper may be helpful for designing the new MMP-9 inhibitors having higher biological activities by carrying out the structural modifications of flavonoid molecules.

关键词： Probabilistic evolution approach   Quantum mechanics   Ehrenfest Theorem   Expectation value dynamics   Kronecker power series   Mathematical fluctuation theory   Quantized Hamilton dynamics   Quantal cumulant dynamics  

摘要： The first part of these two companion papers has been devoted to the extension of Hausdorff moment problem to the sequences over integrals of Kronecker powers of an appropriate vector under a generating function in the kernel. The relations between this generating function and weight function properties have been investigated over there in a quite detailed manner. This second companion paper focuses on the utilization of the "mathematical fluctuation theory" amenities in the construction of approximations to the solutions of the expectation value dynamics of the quantum dynamical systems. The fluctuation freee approximation matching with the classical mechanical behaviour is followed by the first and then the second order fluctuation approximations. Beside the well known "Energy Conservation Law"s counterparts in these approximations of quantum expectation value dynamics are also presented.

关键词： Boriding   Carbon steel   Kinetics   Mechanical properties   Precarburization  

摘要： Boriding is a thermochemical process employed widely for increasing the resistance of ferrous materials to wear and corrosion. In this work, the influence of precarburization on microstructure, boride layer thickness, microhardness, growth kinetics, and mechanical properties of untreated and borocarburized AISI 1015 steel is studied. The thickness of boride layer ranges from 205.9 to 215.9 mm for borocarburized specimens to a maximum of 247.7 mu m for borided AISI 1015 steel. The carbon content in the case improves the microstructure by the formation of single-phase iron boride mainly on the surface. Boride layer thickness decreases with increase in carbon content of the case. Activation energy for the borided AISI 1015 steel is 119.22 KJ/mol. The activation energies are 174.4 and 194.7 KJ/mol for borocarburized AISI 1015 steel having 0.30% C and 0.45% C, respectively. The activation energy increases with increase in carbon content due to precarburization. Empirical relations have been developed to predict boride layer thickness and are well correlated with experimental values for the process temperature and time. Tensile strength ranges from 421 to 599 N/mm(2). Impact strength of borided specimens varies between 386.7 and 493.3 N-m while for borocarburized specimens it ranges between 103.7 N-m and 183.3 N-m. Fracture behavior of borided and borocarburized specimens under tensile and impact tests has been analyzed.

关键词： Rotors   Blades   Instrumentation   Simulation   Engineering simulation   Pressure   Computational fluid dynamics  

摘要： The focus of the present study is to assess and quantify the uncertainty in predicting the steady and unsteady aerodynamic performance as well as the major mechanical characteristics of a contrarotating turbofan, primarily due to geometric variations stemming from the manufacturing process. The basis of this study is the optically scanned blisk of the first rotor, for which geometric variations from blade to blade are considered. In a first step, selected profile sections of the first rotor were evaluated aerodynamically by applying the 2D coupled Euler/boundary-layer solver MISES. Statistical properties of the relevant flow quantities were calculated firstly based on the results of the nine manufactured blades. In a second step, the geometric variations were decomposed into their corresponding eigenforms by means of principal component analysis (PCA). These modes were the basis for carrying out Monte Carlo (MC) simulations in order to analyze in detail the blade's aerodynamic response to the prescribed geometric variations. By means of 3D-computational fluid dynamics (CFD) simulations of the entire fan stage for all the nine scanned rotor 1 blade geometries, the variation of the overall stage performance parameters will be quantified. The impact of the instrumentation will be discussed, here partly doubling the standard deviation of the major performance indicators for the instrumented blades and also triggering a premature laminar/turbulent transition of the boundary layer. In terms of the unsteady blade row interaction, the standard deviation of the resulting blade pressure amplitude shall be discussed based on unsteady simulations, taking advantage of a novel harmonic balance approach. It will be shown that the major uncertainty in terms of the predicted blade pressure amplitude is in the aft part of the front rotor and results from upstream shock/blade interaction. Apart from the aerodynamic performance, an analysis of the mechanical properties in terms of Camp