干式双螺杆空压机气动噪声优化设计

目前国内外干式双螺杆压缩机大多数直接采用了喷油螺杆压缩机的型线，一般通过改变齿数比，适应干式螺杆压缩机低压比和大气量的需求。通过对干式双螺杆空压机型线开展优化设计，将螺杆压缩机型线中瞬时啮合的曲线变为逐点啮合的曲线，避免压缩机螺杆齿面啮合的泵吸作用，从而降低压缩机气动噪声，改善压缩机运行环境。     

螺杆压缩机转子的磨削加工

螺杆压缩机的效率和完全互换性的快速发展，使得对螺杆压缩机转子的型线精度和表面粗糙度的要求越来越高。文中分析了螺杆压缩机转子的加工现状，并结合TG350E数控螺纹磨床，介绍了一种新型的转子加工方法——磨削成形法，同时说明对转子加工设备的一些要求。     

螺杆压缩机新型线的研究与设计

综述了螺杆压缩机转子端面型线的研究与发展状况，分析了对端面型线的基本要求，给出了设计新型一的一般步骤和方法，并利用螺杆压缩机计算机辅助设计系统ＳＣＣＡＤ，设计了两种性能优越的螺杆压缩机新型线。     

联邦德国GHH公司和日本神户制钢所的螺杆压缩机现状

近年来,国外螺杆压缩机发展很快,其应用领域不断扩大,尤为突出的是以生产螺杆压缩机著名的联邦德国GHH公司和螺杆压缩机的产量居世界首位的日本神户制钢所[1、2].他们在引进瑞典SRM螺杆转子技术后,研制成功了新型型线转子,大大提高了螺杆压缩机效率,其比功率已接近比较先进的活塞式压缩机     

基于积累弦长三次样条函数的螺杆齿槽容积计算

针对螺杆压缩机转子型线优化设计及压缩机工作过程仿真的需要，采用积累弦长三次样条函数的型线设计方法，分别建立了阴阳转子型线的参数化方程，并在此基础上建立了螺杆齿槽容积的计算模型，通过一个具体的算例，对齿槽容积随转角变化进行了计算。     

螺杆压缩机转子型线的优化设计

设计了一种新型螺杆压缩机转子型线，利用Hpms型线处理软件，对设计的转子型线进行优化处理，以适合于转子的磨削加工。通过对加工出的转子型线进行检测和分析。表明转子型线的优化设计是成功的，达到了设计要求。     

国外螺杆压缩机简述

非对称型线螺杆压缩机采用非对称型线的转子,是值得注意的国外螺杆式压缩机发展的一个新动向。相对于对称型线的转子而言,非对称型线的转子在制造工艺方面更困难些。但是转子采用非对称型线后,可以使螺杆压缩机获得较高的容积效率,单位排气量的功率消耗也降低。因此,在克服制造工艺困难的基础上,美国英格索尔·兰德(IngersollRand)公     

螺杆压缩机研究进展及应用趋势

螺杆压缩机具有结构简单、操作方便和运转可靠等一系列独特的优点，这类压缩机由瑞典的SRM公司在1937年研制成功。经过持续的基础理论研究和产品开发试验，通过对转子型线的不断改进和专用转子加工设备的开发成功，螺杆压缩机的优越性能得到了不断的发挥，广泛应用于空气动力、工业制冷、中央空调和工艺流程等各种场合。按输气量计算，目前螺杆压缩机制销售总量已占所有容积式压缩机的销售量的80%以上，在所有的正在运行的容积式压缩机中，有50%是螺杆压缩机。图1为螺杆压缩机结构示意图。     

五洋赛德螺杆压缩机控制技术的发展

经过人类半个多世纪的研发，喷油螺杆压缩机主机在其转子型线，啮合线方程，几何特性、刀具及加工技术已趋成熟，螺杆压缩机优越的性能得到了用户的认可。统计数据表明，2004年螺杆压缩机的销售量已占容积式压缩机销售量的70％以上，并有上升趋势。     

螺杆压缩机接触线形状及长度的计算方法

接触线的几何特性对螺杆压缩机的热力学性能与动力学特性分析至关重要,基于空间曲线的啮合定律,用显函数型式给出了型线坐标参数与压缩机转角的关系,提供了计算螺杆压缩机接触线形状及长度的简化方法,并给出了一种典型型线的算法实例,为进一步设计分析高效转子型线提供参考。     

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.