起细金属陶瓷的研究现状

介绍了国内外超细金属陶瓷制备方法的研究现状，比较了超细金属陶瓷与普通金属陶瓷的成分、显微结构、物理性能和切削性能，并对利用细化晶粒来改善金属陶瓷性能的机理进行了分析。     

VC对微米级Ti(CN)基金属陶瓷微观结构和力学性能的影响

VC对于制备微米级的Ti(CN)基金属陶瓷,能够起到控制Ti(CN)晶粒长大的作用,并且能够使烧结体中晶粒粒度分布变得均匀。在液相烧结过程中,由于瓦尔德熟化效应使Ti(CN)晶粒长大,Ti(CN)晶粒的长大又分为连续长大和不连续长大。关于VC的抑制机理,目前还没有明确的结论,但有三种比较有代表性的说法:吸附机制、溶解机制和偏析机制。随着VC添加量的增加,Ti(CN)基金属陶瓷的抗弯强度呈现先升后降的趋势;VC的加入使材料的硬度减小。     

超细金属陶瓷的研究现状

介绍了国内外超细金属陶瓷制备方法的研究现状 ,比较了超细金属陶瓷与普通金属陶瓷的成分、显微结构、物理性能和切削性能 ,并对利用细化晶粒来改善金属陶瓷性能的机理进行了分析。     

放电等离子烧结制备Ti(C,N)基金属陶瓷

用放电等离子烧结(SPS)技术制备了Ti(C，N)基金属陶瓷材料。使用XRD、SEM对烧结体物相、微观组织进行了分析，并对金属陶瓷的硬度、抗弯强度和孔隙率进行了对比分析。结果表明：SPS工艺下形成了Ti(C，N)相；1350℃下保温8min是较佳的烧结工艺。原料粉添加VC后，烧结体晶粒组织明显细化，但孔隙率变大，综合性能仍高于未添加VC的金属陶瓷。     

预烧温度对纳米复合Ti(C,N)基金属陶瓷组织和性能的影响

用真空预烧＋热等静压处理工艺制备了纳米复合Ti（C，N）基金属陶瓷，用SEM和TEM／EDX研究了预烧温度对纳米复合Ti（C，N）基金属陶瓷显微组织和性能的影响。结果表明：随着预烧温度的升高，硬质相颗粒明显球化、细化且分布均匀，具有白芯-灰壳结构的小硬质相颗粒明显增多，且环形相较完整。在1420℃预烧时，金属陶瓷具有较好的力学性能；继续升高顸烧温度时，晶粒会明显长大，环形相变厚、变脆，导致材料的性能下降。综合考虑认为，较佳预烧结温度为1420℃。     

纳米TiN提高金属陶瓷刀具耐磨损性能的机理研究

研究纳米TiN显著提高TiC基金属陶瓷刀具耐磨损性能的机理。结果表明 ,纳米TiN在晶界上的分布阻碍了TiC晶粒的长大 ,细化了金属陶瓷组织 ,提高了强度、硬度等力学性能 ,使金属陶瓷刀具的耐磨损性能提高。     

金属陶瓷表面处理的研究进展

对近年来国内外有关金属陶瓷表面处理的研究成果进行了总结和分析。主要介绍了气相沉积技术、氮化处理和离子注入等在金属陶瓷表面处理中的应用及其对材料晶粒度、组织和性能的影响，指出了金属陶瓷表面处理未来的发展方向。     

稀土对金属陶瓷涂层微观组织改性作用研究现状和应用进展

介绍了稀土对金属陶瓷涂层微观组织改性作用的研究现状和应用进展.稀土对金属陶瓷涂层改性作用表现为细化晶粒、净化组织、产生固溶强化和弥散强化、降低基体材料对涂层的稀释、改善涂层组织力学性能等方面,从而改善了金属陶瓷涂层的微观组织结构.稀土改性技术应用于热喷涂、复合电镀、激光表面熔覆等金属陶瓷涂层制备工艺中,能有效地提高涂层的强度和硬度,增强涂层与基体的结合强度,改善涂层的摩擦学性能,提高金属陶瓷涂层的使用性能.     

纳米陶瓷块体的激光烧结成形实验研究

基于激光熔覆技术，以纳米Al2O3粉体材料为研究对象，研究了纳米陶瓷块体材料制备的技术。研究结果表明，在所用的工艺参数下，能制备出Al2O3陶瓷块体，块体材料内部具有独特的组织结构，晶粒尺寸能保持在原纳米晶粒尺寸范围。与其他烧结方法相比，激光熔覆制备纳米块体材料在保持纳米晶粒不长大的情况下具有明显的优势。     

金属陶瓷表面硬质涂层的制备及其与基体结合强度研究现状

金属陶瓷因既具备金属材料优异的强度、高温导热性和热稳定性，又具备陶瓷材料的耐高温、耐腐蚀等特性而广泛用于制造切削刀具。金属陶瓷耐磨性和硬度不足的问题限制了其应用范围，在其表面制备硬质涂层可以解决这一问题，但是涂层的结合强度弱，易剥落。介绍了硬质涂层的制备方法、涂层与基体结合强度的影响因素，阐述了提高硬质涂层结合强度的方法，最后对金属陶瓷表面硬质涂层的制备技术及结合强度的提高进行了展望。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

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.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.