基于可拓变换的产品性能冲突传导协调方法

针对产品性能设计中的多性能优化冲突问题,提出了一种基于可拓变换的产品性能冲突传导协调方法。利用可拓设计方法量化产品性能需求及形式化建模描述,构建多性能检索机制,确定待优化性能;在此基础上给出触发性能及其与产品结构量化映射机理,输出触发性能满足方案;结合传导协调方法,建立产品性能之间的动态传导关系,形成产品性能设计创新方案。最后以大型螺杆空压机为例,验证了该方法的可行性及有效性。     

梯度功能材料的制备与性能评价

梯度功能材料（FGM）是组分和性能呈连续变化的先进材料,FGM的制备方法与性能评价对其优化设计具有重要意义。对FGM的制备方法与性能评价进行了综述,详细分析了FGM的力学性能、热震性能、压缩性能和热处理性能的评价方法及试验手段,最后指出了FGM性能评价和制备的发展方向。     

基于因果模型的耗能机电产品性能匹配方法研究

针对耗能机电产品性能匹配问题,提出基于因果模型的性能匹配方法。能量是机电产品性能实现的关键因素,通过构建设计变量、能量和性能之间的三层因果模型,计算设计变量对性能的影响程度,通过对影响程度性能高的设计变量匹配优化实现产品性能优化。最后采用家用电冰箱性能匹配设计的案例论证了基于因果模型的耗能产品性能设计方法的有效性。     

《容积式制冷剂压缩机性能试验方法》国家标准中的几个关键问题

针对目前已经报批的《容积式制冷剂压缩机性能试验方法》国家标准,重点阐述了制冷量和制热量的计算方法、配用经济器或闪发器的容积式制冷剂压缩机性能试验方法、跨临界CO2容积式制冷剂压缩机的性能试验方法以及性能测量不确定度计算等关键技术内容。     

汽车制动性能检测方法的比较与分析探究

随着社会经济的不断发展,汽车制动性能的检测方法已经成为汽车工程领域的重点课题。本文通过分析制动系统的工作原理,论述汽车制动系统方面的性能评价指标情况,阐述汽车制动性能检测主要方法,探讨汽车制动性能水平的检测方法的比较与分析。     

基于稳健理论的一种精密轴承性能退化评估方法

精密轴承的性能演变过程可以实现轴承性能评估及寿命预测,对精密设备运行的可靠性与安全性有重要意义。针对精密轴承性能演变的未知分布特征,文中基于稳健理论,采用中位数估计与Huber M估计融合方法研究其性能稳健性及置信水平。为有效在线监测精密轴承性能的演变过程,提出了一种基于稳健理论算法的精密轴承性能退化评估方法。首先,对服役期间轴承振动数据进行定时采集,构成评估对象;然后,用中位数估计与Huber M估计融合方法进行稳健数据分析,以中位数与平均值接近的程度为稳健标准,按照Huber M方法分析采集数据的稳健性,获取不同时间阶段轴承性能的稳健数据与显著性水平;最后,根据参数非参数方法特征,获取轴承性能本征区间、变异率、中位数,以及平均值特征构成评估体系,评估精密轴承性能演变的动态过程。实例验证结果表明：该评估体系参数的变化趋势与滚动轴承性能变化趋势保持一致,变异率与轴承性能失效评价标准完全一致,可以很好评估精密轴承性能退化。因此,该方法无需知道性能数据的分布及置信水平,可以很好地评估精密轴承的性能退化。     

基于等效臂的遥操作机械臂的运动性能优化方法

随着工业技术的发展，遥操作系统被广泛地应用于各领域之中。在遥操作过程中，从臂的运动性能影响着任务的完成效果。因此，希望在从臂跟随人臂轨迹运动的同时，对从臂性能进行优化。然而，现有性能优化方法会改变机械臂的运动状态，导致人臂和机械臂的运动不相似。为此，文章提出了基于等效臂的遥操作性能优化方法。首先，基于等效臂模型建立运动学映射方法，将人臂运动信息完整的映射到机械臂。然后，提出性能优化方法，通过调整等效臂来优化机械臂的运动性能。最后，进行了性能优化实验，实验结果表明性能优化方法能够在保证两臂运动相似性的同时，提升机械臂的性能指标。     

一种提高弹性元件性能的有效方法

弹性元件的性能好坏,直接影响着传感器的性能指标。而提高弹性元件性能的方法很多,本文通过对比的方法,介绍了采用精炼的原材料制造弹性元件以提高其性能的方法以及冶炼方法对材料性能的影响。     

乳化型防锈油暂行试验方法(草案)

文中提出了乳化型防锈油的下列几种试验方法:油剂稳定性试验方法、乳化性能试验方法、乳液耐盐性试验方法、乳液稳定性试验方法、湿热试验方法、盐雾试验方法、乳液润湿性能试验方法、重叠腐蚀试验方法、乳液浸渍腐蚀试验方法、油膜除去性试验方法、乳液起泡性能试验方法、油膜性能试验方法。     

百万吨乙烯装置用丙烯压缩机组闭式循环性能试验

通过丙烯压缩机的性能试验实例,介绍了以代用气体获得实际气体的性能试验方法,试验气体的选用原则和试验条件的确定方法,带有抽加气结构压缩机试验的装置和测点的布置方法和性能计算方法。     

EXPERIMENTAL RESEARCH AND DESIGN ON HEAT TRANSFER OF EVAPORATOR USED IN THE LARGE QUICK FREEZE PLANT

The evaporator is the main part of a quick-freeze equipment. There are many factors influencing the heat transfer coefficient of an evaporator. The most important factors among them are the fin shape, tube diameter, distance of fin space, frost, and velocity of air flow etc. They mainly influence the thermal efficiency of an evaporator, and therefore its thermal efficiency has direct relationship with the whole efficiency of the quick freeze plant. Evaporators with different structural types have different heat transfer efficiency. In order to obtain high efficiency structure of evaporator, 8 evaporator models with different fin shape, tube diameter and tube arrangement are analyzed and compared. The calculation results show that the integral waved fins, equilateral-triangle arranged small diameter tubes and varying fin-spacing has the highest heat transfer coefficient. The experimental result also shows that the evaporator with this type of structure has better thermal efficiency. The experimental result is in good agreement with the calculation result. It can instruct engineering design for usual designer. A real quick-freeze equipment is designed and put into production. The result shows that, compared with traditional domestic quick-freeze equipments, this equipment decreases by 40% in size and by 20% in energy consumption.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

The use of chemiluminescence in determining the thermal and oxidative stability of motor oils

Chemiluminescence is reviewed as a method of characterising different behaviour of lubricating oils. This includes mineral oils containing additives such as zinc dialkyl-dithiophosphates, sulphonates, succinamides. alkylphenols and polymers. Using a chemiluminescence apparatus and manometric apparatus, various lubricant oil fractions blended with additives were examined. The basic emitters of chemiluminescence are excited carbonyl compounds, and results are presented showing the measurement of chemiluminescence at elevated temperatures.     

GENERATE ROUGH TOOL-PATHS FROM UNORGANIZED POINT-CLOUD DIRECTLY

An approach is presented to generate rough interference-free tool-paths directly from massive unorganized data in rough machining that is performed by machining volumes of material in a slice-by-slice manner. Unorganized point-cloud is firstly converted to cross-section data. Then a robust data-structure named tool-path net is constructed to save tool-path data. Optimal algorithms for partitioning sub-cut-areas and computing interference-free cutter-locations are put forward. Finally the tool-paths are linked in a zigzag milling mode, which can be transformed into a traveling sales man problem. The experiment indicates optimal tool paths can be acquired, and high computation efficiency can be obtained and interference can be avoided successfully.     

PHENOMENON OF CARVED DRIVING WHEELS

A newly found phenomenon of carved driving wheels of a rear-wheel-drive tractor used in an airport is discussed. The circum of every driving wheel is damaged at three regions,which distribute regularly and uniformly. Everyday,the tractor tows a trailer which are times heavier than the tractor,and moves on the same road in the airport. The phenomenon is explained by the torsional self-excited vibration system of the powertrain. The simplified torsional vibration system is discribed by a 2-order ordinary differential equation,which has a limit circle. Experiments and numerical simulations show the followings: Because of the heavy trailer,the slip ratio of the tractor’s driving wheels is very large. Therefore,there is severe torsional self-excited vibration in the tractor’s drivetrain,and the self-excited vibration results in severe and regular fluctuations of the rear wheel’s velocity. The severe fluctuations in velocity fastens the damage of the driving wheels. At the same time,the time interval in which an arbitrary point in the circum of the driving wheel contacts with the road twice is two times more than the period of the torsional self-excited vibration,and this times explained the existence of three damaged regions. At last,it points out that the phenomenon can be avoided when the torsional damping is large enough.     

Stromules and the dynamic nature of plastid morphology

Investigation of plastids via green fluorescent protein (GFP) has led to the rediscovery of tubular extensions of the plastid membrane, termed stromules, for stroma‐filled tubules. These unique structures are challenging our understanding of plastid structure and function. Stromules are highly dynamic, branching and elongating across the plant cell. Recent experiments indicate that cytoplasmic microtubules and microfilaments control the shape and motility of stromules. Whether stromule formation involves plastid‐specific structural systems, such as the plastid division machinery, remains open to debate. Fluorescence photobleaching experiments have revealed that GFP can traffic between plastids joined by stromules. As a result, interest has grown in whether other macromolecules can also travel through these connections. Although the function of stromules is unknown, several aspects of their biology suggest they play a role in molecular exchange between plastids and other organelles.     

A microscope diffusion chamber for the determination of the equilibrium and non-equilibrium osmotic response of individual cells

A microscope diffusion chamber has been developed which allows direct observation of the dynamic osmotic response of individual cells in micro-volume suspensions. Continuous observation of stationary cells is possible including short experimental times while the extracellular chemical composition is changed. Multiple changes of solute type or concentration are easily imposed upon a single sample volume. Response times are a function of chamber configuration but response times as low as 1–10 s are possible with negligible solute concentration gradients within the sample region. The chamber is simple and economical to construct and use. It is the size of an ordinary glass microslide and it can be adapted easily to any common laboratory microscope. All standard optical techniques may be used with the chamber. Construction details and operating characteristics including important limitations are discussed. Example photomicrographs and osmotic data are included.     

VOLUME DEFECT FATIGUE FAILURE OF CERAMIC BALLS UNDER ROLLING CONDITION

A newly developed pure rolling fatigue test rig with three contact points is used to test the rolling contact fatigue properties of silicon nitride ceramic balls. Ball surfaces are examined after failure with optical microscopy and scanning electron microscopy. The failure cause,fatigue phenomenon and mechanics are analyzed. The research shows that subsurface cracks play a dominant role in the formation of spalling failure. These cracks originated from volume defects of the material and propagate,to form elliptical fatigue spalls under the action of principal tensile stresses. The principal tensile stress increases with increasing contact load,causing spall formation and reduction of rolling contact life. The greater the principal tensile stress is,the more severe the peeling of near surface is. Under the same condition,the closer volume defects are to the surface,the more likely failure occurs,the shorter the rolling contact life is.     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.     

Multiple-tapped-delay-line hardware-linearisation technique based on wire load regulation

This article describes designing, implementation and tuning processes of multiple-tapped-delay-line (MTDL). Obtained MTDL can be implemented in various field-programmable-logic-devices (FPGA) devices and applied for time-to-digital-converters (TDC) construction. The task of tuning process is the tapped-delay-line (TDL) linearisation, and consists of two stages. The first stage depends on selecting an appropriate configurable-logic-block (CLB) for particular delay-segment realization and selecting proper connection between these blocks. The second tuning stage, that is essential from this article viewpoint, depends on inter CLBs connecting wires delay regulation realized directly by load regulation. The Load regulation depends on connecting an appropriate number of unused three-state-buffers or CLB inputs to the wire which delay is adjusted. Depending on the number of inputs connected to the wire its capacitance changes that influences its time-constant and finally changes its time-delay.The MTDL mathematical model, obtained characteristics and results of time-interval (TI) measurements are also presented. The derived TDL model provides information about how the particular wire delay should be changed and in which order the changes should be executed. This makes the designing process predictable and easy to carry out. Presented characteristics confirm the proper operation of presented linearisation technique. The proper operation of the whole measuring module is confirmed by obtained TIs histograms presentation.