阻性及抗性消声器对离心式通风机噪声影响的声电类比理论和试验研究

本文把离心式通风机旋转噪声和涡流噪声类比成交流电源和直流电源，就阻性及抗性消声器对风机气动力噪声的影响进行了声电类比理论和试验研究，提出了采用消声器降低风机噪声的注意点。     

如何选择消声器的类型降低离心式风机噪声的研究

本文对阻性和抗性消声器对离心式风机噪声的影响进行了声电类比理论分析和试验验证,就某型号离心风机旋转噪声和涡流噪声占的比重进行了试验研究,提出了合理地选择消声器的类型,有效地降低离心风机噪声的几个观点。     

基于TRIZ的二级类比概念设计研究

创新问题解决理论求解领域问题所得到的解及相应的设计实例作为类比设计的源设计,将创新问题解决理论过程转变为第一级类比过程,提出了其过程模型。将上述过程的结果作为情景,按基于情景的类比设计原理,提出了第二级类比过程模型。两级类比过程模型集成形成了基于创新问题解决理论的二级类比概念设计过程模型。该模型分为9步,不仅应用了创新问题解决理论标准化的问题求解过程及已积累的知识库,也能发挥设计人员的创新能力。上述模型已应用于国产圆网造纸机烘干部件的概念创新设计实例中,证明了该模型的有效性。     

基于改进SBF模型的类比设计过程研究

类比设计是利用已有系统的问题解决方案或过程解决相似系统目标问题的创新设计方法。知识表征是类比设计的重要环节,为类比源检索和类比映射提供基础。针对结构-行为-功能(SBF)模型的不足,提出了改进的SBF建模规则,以更合理地表征设计知识。在此基础上,提出功能相似匹配和行为相似匹配的类比源检索方法,及以行为和结构映射为核心的4种类比映射路径,从而形成系统化的类比设计过程模型。该方法有助于设计者扩展设计空间,提高产品创新设计的效率。最后,以双导梁式架桥机的改进设计为例,验证上述研究的可用性和有效性。     

一起塔机倒塌事故的原因分析

针对塔机倒塌的现场特征,对导致倒塌的各种迹象实施采样、取证、试验、研究,根据对设备的受力工况经过反推、类比计算后,得出倒塌的原因分析结论。     

电子天平标准GB/T 26497-2011电磁兼容问题探讨

本文主要就电子天平标准GB/T 26497-2011在型式评价试验中的电磁兼容试验的具体要求与电子台案秤进行类比,并对标准中的相关问题进行探讨。     

应用C型风室装置进行风机进气试验的数值模拟与分析

采用理论分析与CFD数值模拟相结合的方法,研究和探讨了进气风室试验装置与进气风管试验装置测试结果产生误差的机理与修正方法。尝试通过理论计算的方法对进气风管与进气风室试验装置间的试验误差进行了修正,将修正后两者的误差控制在工程误差范围内,对风室试验与风管试验结果进行类比分析和修正提供理论参考。     

基于TRIZ及功能类比的产品概念设计创新*

介绍了类比源设计与功能类比作用原理,从两者作用原理及发明问题求解理论(Theory of inventive problem solving,TRIZ)的相关性描述得到启发,提出基于TRIZ的类比源设计求解过程模型。首先,借助于所建立的产品功能结构模型,找出用户需求与产品各功能之间的关联性。其次,将用户需求权重值赋予相关的产品各分功能,从而得到产品功能相似度矩阵,再利用Matlab工具对该矩阵进行标准化,这有利于类比源设计与待设计问题之间相关性的定量化表示。最后,构建出一种基于TRIZ及功能类比的概念设计过程模型。以紫外光油烟净化机为例,对其功能类比源设计的功能相似度进行分析,并利用有效价值分析法对所获得的功能原理解方案进行评价,验证了所构建模型的正确性。     

液─液气射流泵基本性能及其修正系数的研究

研究得出了液—液气射流泵的基本性能方程，与国外同类资料作了类比，导出了模型中各修正系数的表达式，经试验证实了模型的正确性。实验还发现二相液气射流果与液体射流泵性能在极限工况上有很大的差异。     

相似理论和量纲分析在机床设计中的应用(一)

本文论述了相似理论和量纲分析的原理和相似指标、相似准数的确定方法以及在机床结构设计和试验中的应用。它对合理制订系列产品的技术参数、使类比设计更加合理、减少试验工作量等有一定的现实意义。     

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...     

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.     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

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.