关键词： 工程机械液压系统   动力控制   控制技术  

摘要： 工程机械液压系统动力控制技术是一门正在研发的高新技术,若用于工程机械将大大提高机器性能和工作效率。该技术研究涉及电力控制、液压系统控制与发动机三个专业技术的汇集融合。该控制技术包括:单泵恒功率控制技术、负反馈交叉传感功率控制技术、交叉传感控制技术、总功率控制技术、分功率控制技术,以及计算机控制功率优化的控制技术等。

关键词： 农业机械总动力   农产品出口   向量自回归模型   脉冲响应   方差分析  

摘要： 在1981—2013年相关经济数据的基础上,运用向量回归(VAR)模型方法,从实证角度分析了我国农业机械总动力和农产品出口之间的动态关系。各项检验结果表明,我国农业机械总动力和农产品出口之间存在双向因果关系,适合建立向量回归模型。采用VAR模型、脉冲响应分析和方差分析方法,对农业机械总动力和农产品出口之间的动态响应关系进行计量研究,结果表明我国农业机械总动力对我国农产品出口具有长期的正影响。

关键词： 工程机械   液压系统   动力匹配  

摘要： 在工程机械液压系统中,动力匹配与控制技术可以很好地将发动机、液压技术与PLC技术等有机组合与链接。但目前此技术的开发还存在问题和难点,因此需要国家加大科研投入开展技术攻关,促进使工程机械向自动化、智能化方向发展。

关键词： THULIUM   YTTERBIUM compounds   AQUEOUS solutions   QUANTUM mechanics   MOLECULAR dynamics   HYDRATION   RARE earth ions   ABSTRACTS  

摘要： Hydration properties of trivalent thulium and ytterbium ions in aqueous solution are investigated via quantum mechanical charge field molecular dynamics (QMCF-MD) simulations. The QMCF-MD formalism is a special type of QM/MM simulation, where the chemically most relevant part of the system - in this case the ion with its first and second hydration shells - is treated by quantum mechanics. The mean ion-O distances and the average coordination numbers of the first hydration shells are compared with experimental EXAFS data. Mean ligand residence times, vibrational frequencies and force constants were evaluated to characterise the dynamics of the systems. (C) 2015 Elsevier B.V. All rights reserved.

关键词： 机械设计制造   学院   三峡大学   能源与动力工程   机械电子工程   材料成型   机械工程   控制工程  

摘要： 2014年1月原机械与材料学院更名为机械与动力学院，学院现设有机械设计制造及其自动化、机械电子工程、材料成型及控制工程、工业工程、能源与动力工程、核工程与核技术六个本科专业，其中机械设计制造及其自动化为国家特色专业、第二批卓越工程师教育培养计划专业和省本科品牌专业，材料成型及控制工程为第三批卓越工程师教育培养计划专业。拥有机械工程一级硕士点、机械工程专业学位点、机械工程领域工程硕士点、工业工程专业学位点，机械制造及其自动化为湖北省重点学科。

关键词： 机械工程   新余市   动力学   中国计量测试学会   学院   学术   制造   功能  

摘要： 2015年8月8日上午，由江西省新余市人民政府、中国振动工程学会机械动力学学会、中国机械工程学会生产工程分会机床专业委员会、中国计量测试学会在线检测技术专业委员会主办。新余学院承办的2015国际功能制造与机械动力学学术大会在新余市会展中心隆重召开。

关键词： SVM脉宽调制   转矩控制   磁连控制   电磁脉动  

摘要： 针对混合动力工程机械永磁同步电动机直接转矩控制系统电磁转矩脉动过大的缺点,在详细分析影响磁链和转矩脉动大小因素的基础上,重新建立了基于SVM调制的永磁同步电机直接转矩的控制框图,在MATLAB/Simulink中对传统永磁同步电机直接转矩控制和改进后的转矩控制系统方法进行了仿真对比研究,结果表明,新的系统能有效减少转矩和磁链的脉动,最后进行了实验验证。

关键词： Molecular dynamics   Interfacial mechanical property   Wrinkled graphene sheet   Nanocomposites   Pull-out  

摘要： Interfacial mechanical properties between nanofiller and matrix in various nanocomposites are extremely important for the load transfer capability between the nanofiller and the matrix. In this study, molecular dynamics (MD) simulations were carried out to investigate the interfacial mechanical properties of polyethylene (PE) and poly (methyl methacrylate) (PMMA) polymer nanocomposites reinforced by graphene. The influences of graphene wrinkles, matrix type, polymer chain length, and pull-out velocity of graphene sheet (GR) on the interfacial mechanical properties were systematically explored. The results show that compared with a flat GR, a wrinkled GR can effectively enhance the interfacial mechanical properties. The pull-out velocity of wrinkled GR has a great impact on the interfacial mechanical properties of both the GR/PE and GR/PMMA nanocomposites. The influence of the polymer molecule chain length on the interfacial mechanical properties is small in the GR/PE system, but very significant in the GR/PMMA system. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Sewage sludge   Thermo-chemical process   Recalcitrant pollutants   Wastewater treatment   Adsorption  

摘要： In the present study, the performance of sewage sludge based adsorbents was examined for the removal of two recalcitrant pollutants (i.e. lignin and amoxicillin) from synthetic wastewater solutions (adsorbate concentration = 50-250 mg/l). The effect of various reaction parameters such as wastewater pH, adsorbent dosage and temperature was studied. Possible mechanisms for the adsorption process have been proposed which depends upon the behaviour of adsorbent surface and adsorbate molecules under specific reaction conditions. Three-parameter Redlich-Peterson isotherm model was found the best fit to the equilibrium data. Pseudo first and second order models validated the kinetic data for lignin and amoxicillin adsorption systems, respectively and the corresponding activation energy was 3.5-4.5 and 12-22 kJ/mol. The nature of adsorption was elucidated from the thermodynamic parameters. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： THERMOPLASTIC composites   PULTRUSION   CRYSTALLIZATION kinetics   ISOTHERMAL processes   POLYMERS  

摘要： A thermoplastic pultrusion was carried out to prepare the long fiber reinforced thermoplastic (LFT) composites based on polyacetal (POM) matrix on the custom-designed pultrusion equipment. The investigation on mechanical performance revealed that the POM-based LFT composites achieved much higher tensile, flexural, and impact strength than the short glass fiber reinforced ones at the same fiber loadings. Such a promising reinforcement effect is attributed to the feature that the residual fiber length in the injection-molded LFT products is greatly superior to that in short fiber reinforced ones. This takes full advantage of the strength of the reinforcing fiber itself. The scanning electronic microscopy demonstrated that the fiber fracture and fiber pull-out concurred on the tensile and impact fracture surfaces, and the former preceded the latter. The isothermal crystallization kinetics of the POM-based LFT composites was also intensively studied, and the results indicated that the crystallinity of POM domain was enhanced by the heterogeneous nucleation of glass fiber, but the crystallization rate was postponed due to the interspace restriction toward crystalline growth caused by long glass fiber. These kinetic parameters provided information on the processing conditions of POM-based LFT composites for the injection and compression molding. (C) 2014 Society of Plastics Engineers