LabWindows/CVI在发动机机械状态实时监测中的应用

介绍了计算机测控系统应用软件开发平台LabWindows/CVI的特点,基于LabWindows/CVI平台的发动机机械状态实时监测系统的基本组成,开发过程中遇到的几个关键问题,及其该发动机机械状态实时监测系统的简单应用案例。结果表明该系统能够有效实现发动机机械状态实时监测。作为新型的测控软件平台之一,LabWindows/CVI极大地提高了开发应用软件的效率,同时也增强了发动机应用软件的系统功能。

四川油菜毯状苗机械化高效移栽技术及发展现状

本文从生产实践出发,详细阐述了四川油菜毯状苗机械化高效移栽播前准备、种子处理、播种育苗、机械移栽、田间管理、植保等环节的技术路线。示范推广成效显示该技术是一项农机农艺高度融合的油菜种植技术,具有作业效率高、适应性强、技术通用性好、茬口衔接时间长和增产效果显著的优点,但也存在育苗成本较高、育苗技术不易掌握、移栽机械价格高等不足,提出了加强财政支持、完善产学研用机制和切实加强前期油菜苗期管理等建议。

心耳状机械吻合术防治食管贲门癌术后吻合口狭窄51例

1999年3月至2003年4月,作者采用心耳状机械吻合术防治食管贲门癌术后吻合口狭窄,疗效满意,报道如下.

基于囊状颗粒物的新型机械手

机械手是机器人的重要组件之一,由于传统通用机械手都是由多个独立活动关节构成的仿人多指机械手,需要大量的复杂结构和计算,从而导致其相应的高成本,同时,传统通用机械手响应时间长,抓取动作缓慢且不能完全适应目标物体的形状,甚至可能损坏目标物体。因此,针对传统通用机械手的诸多缺陷,设计一种新型的被动式机械手,方法是由大量的小颗粒物质包裹在一个球状弹性膜中,利用空气正压-负压的组合使弹性膜内的微小颗粒物质可以在松散-游离状态相互转换,使得它可以迅速地抓取和释放普通通用机械手难以抓取的具备复杂外形的物体,并具有形状适应性强、控制简单、可靠性高、执行效率高以及成本低等优点。

江汉平原水稻钵形毯状秧苗机插技术研究初报

水稻钵形毯状秧苗机插技术解决了普通塑料盘毯状秧苗插秧植伤重、秧苗本田缓苗期长、返青分蘖慢的技术缺陷。通过对该技术的引进、研究、示范与推广,总结出了江汉平原水稻生产应用钵形毯状秧苗机插关键技术。

集装箱机械自动化控制及通讯应用与设想（一）

本文着重对以下几个主要问题进行介绍：①美国GE公司和日本安川公司的起重机控制系统在桥吊上的应用情况和以上两个系统的工作。②全球定位系统（GPS）在轮胎吊上的应用。③起重机远程管理系统的应用情况。④今后发展方向和系统优化的设想。

Microstructural effects in corrosion of aluminium tube alloys

Fine gauge extruded aluminium alloy tubes can experience preferential corrosion and early failure when they are formed into ＂u-bend＂ via cold deformation. The relationship between the electrochemical reactivity and the microstructure of the bent vs straight parts of the tube was established. Investigations were carried out on two alloys containing 0.08% and 0.22% （mass fraction） of manganese. The corrosion morphology of bent tubes after immersion in salt water acetic acid test （SWAAT） solution showed the highest attack at the bent region of the high-Mn alloy. SEM characterisation of the alloys showed that each alloy has one main type of coarse intermetallic particle. However, TEM observation showed that there is a distinct difference in particle morphology between the bent and straight regions of the high-Mn tubes, the bent region revealed an additional population of 10 50 nm Mn-rich intermetallic particles, which increased both the anodic and cathodic reactivity. For the low-Mn alloy, no such effects were observed. The results suggested that cold deformation of the high-Mn tube allowed room temperature precipitation of fine Mn-rich particles, which increased the cathodic reactivity of that region by providing more cathodic sites, and increased the susceptibility to pitting by removing noble Mn from solid solution. Such an effect was not observed for the low-Mn alloy.

Analysis of the dialectical relation between top coal caving and coal-gas outbtu rst

According to the different engineering mechanical states of top coal caving andnormal stoping of gaseous loose thick coal seams,the dialectical relation between thiscaving method and dynamic disasters was analyzed by simulating the change of stressstates in the process of top coal initial caving with different mining and caving ratios basedon the ANSYS10.0.The variation of elastic energy and methane expansion energy duringfirst top coal caving was analyzed by first weighting and periodic weighting and combiningwith coal stress and deformation distribution of top coal normal stoping as well as positiveand negative examples in top coal caving of outburst coal seam.The research shows thatthe outburst risk increases along with the increase of the caving ratio in the initial miningstage.In the period of normal stoping,when the mining and caving ratio is smaller than1:3 and hard and massive overlying strata do not exist (periodic weighting is not obvious),it is beneficial to control ground stress leading type outburst.Thus,it is unreasonable toprohibit top coal caving in dangerous and outburst prone areas.

上海浦东国际机场航站楼特大型斜挑悬索拱形钢屋盖安装工艺及设备的研究

本工程的特大型斜挑悬索拱形钢屋盖为国内外罕见,经过多方案的研究比较和优化,采用“屋架节间地面拼装,柱梁屋盖跨端组合,区段整体纵向移位”和“地面组装,四机抬吊,高位负荷,远程吊运”的技术路线,完成了航站楼和登机长廊的屋盖安装。

Intestinal mucosal atrophy and adaptation

Mucosal adaptation is an essential process in gut ho- meostasis. The intestinal mucosa adapts to a range of pathological conditions including starvation, short-gut syndrome, obesity, and bariatric surgery. Broadly, these adaptive functions can be grouped into proliferation and differentiation. These are influenced by diverse interactions with hormonal, immune, dietary, nervous, and mechanical stimuli. It seems likely that clinical out- comes can be improved by manipulating the physiol- ogy of adaptation. This review will summarize current understanding of the basic science surrounding adapta- tion, delineate the wide range of potential targets for therapeutic intervention, and discuss how these might be incorporated into an overall treatment plan. Deeper insight into the physiologic basis of adaptation will identify further targets for intervention to improve clini- cal outcomes.

Optimal Decoupling Control Method and Its Application to a Ball Mill Coal-pulverizing System

Abstract-The conventional optimal tracking control method cannot realize decoupling control of linear systems with a strong coupling property. To solve this problem, in this paper, an optimal decoupling control method is proposed, which can simultaneousiy provide optimal performance. The optimal decoupling controller is composed of an inner-loop decoupling controller and an outer-loop optimal tracking controller. First, by introducing one virtual control variable, the original differential equation on state is converted to a generalized system on output. Then, by introducing the other virtual control variable, and viewing the coupling terms as the measurable disturbances, the generalized system is open-loop decoupled. Finally, for the decoupled system, the optimal tracking control method is used. It is proved that the decoupling control is optimal for a certain performance index. Simulations on a ball mill coal-pulverizing system are conducted. The results show the effectiveness and superiority of the proposed method as compared with the conventional optimal quadratic tracking （LQT） control method.

Hierarchical 3D mechanical parts matching based-on adjustable geometry and topology similarity measurements

A hierarchical scheme of feature-based model similarity measurement was proposed,named CSG_D2,in which both geometry similarity and topology similarity were applied.The features of 3D mechanical part were constructed by a series of primitive features with tree structure,as a form of constructive solid geometry(CSG) tree.The D2 shape distributions of these features were extracted for geometry similarity measurement,and the pose vector and non-disappeared proportion of each leaf node were gained for topology similarity measurement.Based on these,the dissimilarity between the query and the candidate was accessed by level-by-level CSG tree comparisons.With the adjustable weights,our scheme satisfies different comparison emphasis on the geometry or topology similarity.The assessment results from CSG_D2 demonstrate more discriminative than those from D2 in the analysis of precision-recall and similarity matrix.Finally,an experimental search engine is applied for mechanical parts reuse by using CSG_D2,which is convenient for the mechanical design process.

Research progress and prospects on machinery monitoring under varying working condition

A general review is given about the research progress of the rotating machinery condition monitoring under varying working condition. The major typical methods for analyzing are reviewed,including their progress,deficiencies and capabilities. Some prospects are given finally.

Stress-induced martensite phase transformation of FeMnSiCrNi shape memory alloy subjected to mechanical vibrating polishing

Fe66Mn15Si5Cr9Ni5(wt.%)shape memory alloy(SMA)withγaustenite andεmartensite was subjected to mechanical vibrating polishing and consequently its surface suffered from plastic deformation in the case of compressive stress.Almost completeεmartensite transformation is found to occur in FeMnSiCrNi sample subjected to mechanical vibrating polishing,where stress-induced martensite transformation plays a predominant role.Stressinduced martensite transformation of FeMnSiCrNi SMA is closely related to the orientation of external stress.The complicated compressive stress which results from the mechanical vibrating polishing contributes toεmartensite transformation fromγaustenite of FeMnSiCrNi SMA.Mechanical vibrating polishing has a certain influence on the surface texture ofεmartensite of FeMnSiCrNi SMA,where■<0001>texture appears in the polished FeMnSiCrNi SMA.

Mechanical Stimulus Inhibits the Growth of a Bone Tissue Model Cultured In Vitro

Objectives To construct the cancellous bone explant model and a method of culturing these bone tissues in vitro, and to investigate the effect of mechanical load on growth of cancellous bone tissue in vtro. Methods Cancellous bone were extracted from rabbit femoral head and cut into I-ram-thick and 8-ram-diameter slices under sterile conditions. HE staining and scanning electron microscopy were employed to identify the histomorphology of the model after being cultured with a new dynamic load and circulating perfusion bioreactor system for 0, 3, 5, and 7 days, respectively. We built a three-dimensional model using microCT and analyzed the loading effects using finite element analysis. The model was subjected to mechanical load of 1000, 2000, 3000, and 4000 με respectively for 30 minutes per day. After 5 days of continuous stimuli, the activities of alkaline phosphatase （AKP） and tartrate-resistant acid phosphatase （TRAP） were detected. Apoptosis was analyzed by DNA ladder detection and caspase-3/8/9 activity detection. Results After being cultured for 3, 5, and 7 days, the bone explant model grew well. HE staining showed the apparent nucleus in cells at the each indicated time, and electron microscope revealed the living cells in the bone tissue. The activities of AKP and TRAP in the bone explant model under mechanical load of 3000 and 4000 με were significantly lower than those in the unstressed bone tissues （all P〈0.05）. DNA ladders were seen in the bone tissue under 3000 and 4000με mechanical load. Moreover, there was significant enhancement in the activities of caspase-3/8/9 in the mechanical stress group of 3000 and 4000 με （all P〈0.05）. Conclusions The cancellous bone explant model extracted from the rabbit femoral head could be alive at least for 7 days in the dynamic load and circulating perfusion bioreactor system, however, pathological mechanical load could affect the bone tissue growth by apoptosis in vitro. The differentiation of osteobiasts and osteoclasts might be inhibited after the model is stimulated by mechanical load of 3000 and 4000 με.

Mechanical properties and energy mechanism of saturated sandstones

The effects of saturation on post-peak mechanical properties and energy features are main focal points for sandstones. To obtain these important attributes, post-peak cyclic loading and unloading tests were conducted on sandstone rock samples under natural and saturated states using the RMT-150B rock mechanics testing system. After successful processing of these tests, comparisons of stress-strain, strength, deformation, damage, and degradation of mechanical properties, wave velocity, and energy features of sandstone were conducted between natural and saturated states. The results show that saturation has evident weakening effects on uniaxial cyclic loading and unloading strength and elastic modulus of post-peak fracture sandstone. With the increase of post-peak loading and unloading period, the increases in amplitude of peak axial, lateral, and volumetric strains are all enhanced at approximately constant speed under the natural state. The increase in amplitude of axial peak strain is also enhanced at approximately constant speed, while the amplitudes of lateral and volumetric peak strains increase significantly under the saturated state. Compared with the natural state, the increase in amplitude of saturated samples＇ peak lateral and volumetric strains, and the post-peak cyclic loading and unloading period all conform to the linearly increasing relationship. Under natural and saturated states, the damage factor （the plastic shear strain） of each rock sample gradually increases with the increase of post-peak cyclic loading and unloading period, and the crack damage stress of each rock sample declines rapidly at first and tends to reach a constant value later with the increase in plastic shear strain. Under natural and saturated states, the wave velocities of rock samples all decrease in the process of post-peak cyclic loading and unloading with the increase in plastic shear strain. The wave velocities of rock samples and plastic shear strain conform to the exponential relationship with a constant. Saturation reduces the total absorption energy, dissipated energy, and elastic strain energy of rock samples.

Development of process energy intensity formula under different state variables

In a production process, the actual energy consumption is greatly affected by the production state. Certain processing operations are classified into six states, including normal production, abnormal production, planned overhaul, unplanned overhaul, transitional period from unplanned overhaul to normal production (referred for short as unplanned transition) and transitional period from planned overhaul to normal production (referred for short as planned transition). The article takes the analysis of relationship between different states of a certain processing operation and corresponding energy consumptions as a startup point to develop a process energy intensity formula with variables of operating rate, yielding rate and operating frequency, etc. This process energy intensity formula can be used to analyze effectively the pattern of impact exerted by different state variables on energy consumption.

Convergence of shape optimization calculations of mechanical components using adaptive biological growth and iterative finite element methods

Shape optimization of mechanical components is one of the issues that have been considered in recent years. Different methods were presented such as adaptive biological for reducing costs and increasing accuracy. The effects of step factor, the number of control points and the definition way of control points coordinates in convergence rate were studied. A code was written using ANSYS Parametric Design Language (APDL) which receives the studied parameters as input and obtains the optimum shape for the components. The results show that for achieving successful optimization, step factor should be in a specific range. It is found that the use of any coordinate system in defining control points coordinates and selection of any direction for stimulus vector of algorithm will also result in optimum shape. Furthermore, by increasing the number of control points, some non-uniformities are created in the studied boundary. Achieving acceptable accuracy seems impossible due to the creation of saw form at the studied boundary which is called "saw position".

Arduino Based Planar Two DoF Robot Manipulator

In this research, two DoF five bar robot manipulator is controlled by using a human-machine interface program working in a computer. The human machine interface program is developed in Visual C#. Net environment after completing inverse kinematic analysis of the robot manipulator. Human machine interface in computer screen calculates two rotational joint variables for given positions of the robot end point. Then the computer program sends a data package containing these joint variables to Arduino microcontxoller. Arduino microcontxoller set the position of two servo motors according to calculated joint angles. Any position in workspace can be obtained by using the algorithm. The robot can follow traj ectories such as a line, a circle and a rectangle. Furthermore, a lot of patterns can be generated using function with variable radius and angle of rotation.

Study on precision cutting technology of complex shape microparts

Relatively to non-traditional and high-energy-beam micro-manufacturing technique, the micro-cutting technology has many merits. For instance, the machining range is bigger, the cost of equipments is much lower, and the productivity and machining accuracy are higher. Therefore, the micro-cutting technology will take an important effect on the machining technique of complex shape microparts. In this paper, based on selfly-developed machine tool, the precision cutting technology of complex shape microparts made of metal material was studied by analyzing the modeling method on complex shape, the means of toolpaths layout and the optimal selection for cutting parameters. On the basis of above work, a typical duralumin specimen of high precision, low surface roughness and complex shape micropart was manufactured. This result will provide favorable technical support for farther research on the micro-cutting technology.