新型高效电磁驱动反力作动器的设计及特性研究

设计了一种新型高效电磁驱动反力作动器，进行了作动器的磁场计算，利用Ansys软件对其弹簧刚度进行了分析。建立了作动器的力传递模型，通过Matlab软件对其力传递特性进行了仿真分析。以正弦信号输入对作动器的作动特性进行了试验，结果表明作动力大，作动器性能良好，可以很好适用于各种振动系统的主动振动控制。     

新型高效电磁反力作动器的设计

针对发动机振动主动控制系统设计了一种高性能电磁反力作动器。首先简单介绍了作动器的设计要求以及结构原理,接着对作动器的磁场进行了近似计算,并将作动器的力传递模型简化为单自由度振动系统,计算了作动器的作动力。最后通过Simulink软件对其作动力进行了仿真,并以正弦信号输入对作动器的作动力进行了性能试验。结果表明作动力大,作动器性能良好,这对发动机振动主动控制系统的实现以及开展其他主动控制系统的研究具有非常重要的意义。     

基于可控性柱面网壳结构主动控制作动器布置的优化研究

利用磁致伸缩材料的磁控特性制作的作动器可以对结构进行主动控制。首先分析了这种作动器的工作原理和设计方法,并通过实验对其进行了输出性能测试。接着在对作动器进行动力学建模的基础上,推导出整个柱面网壳结构的作动控制方程,同时基于作动效率,提出了不依赖于控制方法的位置优化准则,并且在综合考虑控制效果系数、硬件成本和系统复杂性等因素的基础上,初步确定了作动器的数量,然后采用遗传算法,对作动器的布置位置进行了优化。最后利用LQR主动控制算法,对一柱面网壳模型结构进行了主动控制分析。结果表明,通过优化布置的作动器能够有效地减小结构的动力反应,是一种较好的主动控制方法。此外,主动控制模拟结果也验证了应用遗传算法优化此类问题的优越性和可靠性。     

磁控形状记忆合金主动控制系统及试验研究

对磁控形状记忆合金材料进行了磁力学性能试验研究,建立了预加压力-磁场-应变等磁力学本构模型;系统地分析了磁控形状记忆合金作动器的工作原理和构造方法,并进行了相应的磁场-作动性能试验研究,得出了磁控形状记忆合金作动器的本构模型,集成和开发了主动控制系统,并对一凯威特型模型结构进行了相应的控制性能试验。结果表明,研发的磁控形状记忆合金主动控制系统可有效控制网壳结构的地震响应。     

结构地震响应控制的优化方法

针对大跨空间结构地震响应主动控制,以超磁致伸缩材料为核心元件设计了一种可以应用于大跨空间结构振动主动控制中的超磁致伸缩作动器,制作出了作动器的原型并对其进行了输出性能测试。使用遗传算法对大跨空间结构主动控制作动器的布置位置进行了优化设计,最后进行了优化效果的数值模拟分析。以此验证了超磁致伸缩作动器具有良好的作动效应,利用遗传算法在大大提高结构主动控制优化设计效率时,可以保证实现对结构的整体优化以及作动器能高效、经济地实现对结构进行主动控制的目的。     

直升机结构响应主动控制作动器优化设计研究

采用子结构综合法建立考虑作动器动特性与其相互影响的直升机机身／多作动器耦合系统频域数学模型，研究了直升机结构响应主动控制中采用作动器位置序号进行编码的遗传算法对多作动器位置进行优选，以及与电磁式惯性型作动器参数优化的综合优化问题，进行了结构响应主动控制试验研究，验证了多作动器减振的有效性和所提出的作动器位置优选方法的正确性。     

超磁致伸缩微位移致动器的研究

 基于超磁致伸缩材料的磁致伸缩特性设计了一种用于微位移驱动的致动器．分析了致动器工作磁场的组成，计算了线圈的工作电流，并以此为依据设计了稳流电源．分析结果表明，设计的稳流电源满足工作要求；线圈提供的工作磁场能够保证超磁致伸缩棒工作在线性区域。     

压电智能桁架作动器的数目和位置的优化配置

由于离散型智能桁架结构的固有特性和作动器的优化配置是高度耦合的,即结构的固有特性影响着作动器的优化配置,相应地,作动器配置的数目和位置反过来影响结构的固有特性,很难预先给定一个作动器数目的确定准则.利用优化的方法来讨论压电类结构中作动器数目和位置的优化配置是一种较好的选择.基于结构耦合模态的最优控制,建立了考虑作动器数目和位置优化配置以及控制器参数的优化模型.针对设计变量,提出了一种基于遗传算法的优化策略.数值算例的结果表明,采用优化的方法来确定作动器的优化配置是可行的、有效的.     

磁控形状记忆合金在结构振动控制中的应用研究

磁控形状记忆合金(MSMA)是一种在磁场控制下可产生较大变形,且具有形状记忆功能的新型智能材料,利用其磁控特性可以制作智能作动器进行结构的振动控制。首先介绍了MSMA材料在磁场作用下的变形机理与磁控特性,在此基础上提出了两种可以应用于结构振动控制中的新型MSMA驱动器,并分析了其工作原理和设计方法,最后阐述了利用MSMA的逆特性制作MSMA自传感作动器的关键技术及解决方法,为其在土木工程领域的应用打下了良好的基础。     

一种基于磁流变效应的外骨骼作动器设计及分析

针对穿戴式外骨骼长时间保持姿态困难、驱动系统刚度难以精准控制等问题，设计了一种基于磁流变效应的外骨骼作动器，实现人体长时间站立、蹲坐等姿态保持以及刚柔耦合自适应调整，有效提高穿戴舒适性及随动性。采用SolidWorks、Maxwell及MATLAB联合仿真技术对外骨骼作动器不同状态进行了相关磁场力分析实验，实验结果表明，外骨骼作动器在4A电流驱动下，在θ=π/2实现最大379N的输出力。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.