弹载电子设备相变热沉装置散热性能研究

文中介绍了一种用于弹载电子设备的相变热沉装置的设计方法及试验研究。通过实验对比了电子模块在采用相变热沉装置、铝块和无热沉3种情况下的工作温度曲线,同时对比分析了相变热沉装置在不同热流密度下的工作特性。结果表明,当热源热流密度较小时,相变热沉装置具有明显的减缓热源升温的作用,对比铝块热沉具有明显的散热功效。而随着热流密度的增加,其散热优势逐渐减弱。同时,填料相变温度点的选取和导热增强体的设计,对相变热沉装置的散热性能有很大的影响。     

某弹载电子设备热设计研究

随着大功率电子器件和大规模集成电路在弹载电子设备中的普遍应用,其散热难题日益突出。现结合某小型弹载雷达的热设计,对弹载电子设备的散热技术进行了研究。通过仿真手段,分析了大热耗元器件的瞬态工作温度变化,并开展了导热路径优化设计和相变储热设计,分析结果表明优化设计后,芯片温度明显降低,满足其工作温度指标要求。     

基于相变材料和均热板的复合散热技术研究

弹载、机载等平台的雷达干扰设备的工作环境及安装空间要求越来越苛刻,集成度越来越高,同时发射功率需求日益增大,导致设备的热流密度数倍增加,对设备的散热提出了更高的要求。文中采用单一铝实体、铝与相变材料、铝与相变均热板复合3种热沉,通过试验对比其散热效果。结果表明铝与相变均热板复合热沉在综合考虑散热和减重方面具有一定优势。     

VPX架构下高热流密度电子设备热设计

随着电子设备的国产化、小型化以及各种功能的进一步集成,其热流密度不断增大,对电子设备的热设计提出了更高的要求.文中基于VITA48.2定义的VPX模块进行电子设备整机热设计,提出了一种满足高热流密度VPX模块散热要求的整机结构形式,分析了该种散热结构的热阻网络,并通过6sigma软件进行了热仿真分析,根据仿真结果优化热...     

某弹载电子机箱的热设计

针对弹载电子机箱在恶劣环境下的散热问题,开展了密闭式机箱的热设计工作。基于理论与仿真相结合的分析方式,首先合理优化机箱表面翅片参数,增加散热面积;其次改善电子机箱壳体框架,减小壳体间接触热阻;最后引入均温板的模块壳体,提高内部传热效率;通过与储热板的模块壳体对比分析,探索新的弹载电子机箱热设计,来满足弹载环境温升要求,保证内部电路正常工作。     

某密闭电子设备的热设计

介绍了电子设备热设计的基本内容,阐述了应用热分析软件的设计流程。采用Icepak软件对某密闭电子设备的原始设计进行了热仿真,从结果中找出了关键发热器件和影响散热的薄弱环节。通过调整关键发热器件的散热方式和机箱的整体散热结构,对密闭电子设备的结构进行了优化,使其满足了热设计要求。     

弹上大功率伺服驱动器散热设计与仿真

针对弹上大功率伺服驱动器功率模块的散热问题,提出一种采用相变材料储热的温控方案。通过对功率模块的发热量和所需相变储热材料体积的理论计算,分析该方案的可行性;利用仿真软件对驱动器进行建模并对相变材料储热方案进行仿真,对比分析驱动器自然散热和采用相变材料储热的效果。结果证明：该方案对于大功率伺服驱动器的温控效果显著,能够将功率模块温度控制在正常工作范围内。     

某伺服控制模块热仿真分析及优化设计

随着芯片的集成度和功率越来越高,模块级电子设备的热设计问题日益突出.文中利用Icepak软件对某伺服控制模块进行热设计.基于热分析理论,在模块上加工散热翅片,并分析不同翅片厚度和翅片间距对温度分布的影响,最终得到满足温度要求和加工要求的热设计.结果表明,散热翅片可以在不增加额外冷却设备及不增大模块外形尺寸的前提下有效降低模块整体温度.文中的分析方法可为模块级电子设备的热设计提供参考.     

空间相机电子设备热控系统设计

摘要：为了解决大功率的空间相机电子设备的散热问题,对其热控系统进行了设计与仿真分析。针对需要散热的电子元器件、印制板以及机箱采取了加导热片、表面发黑处理、涂导热填料等导热和辐射方式进行散热。根据电子设备的空间环境和采取的热控措施,应用TMG软件建立了热分析模型,对其热控系统进行了仿真分析,同时进行了电子元器件的结温计算。结果表明,电子设备的印制板的温度范围为35.6℃～45℃,电子元器件的结温温度范围为45.4℃～88.5℃,均低于降额热控温度指标。热控系统设计合理,所采取的热控措施能够满足设计要求。     

一种星载电子设备散热结构的设计与优化

热沉面在顶面的芯片的散热结构设计一直是星载电子设备热设计的难题,常见的散热结构方案是采用和PCB等大小的整块金属导热板扣压在需要散热的芯片上进行散热,这增加了一些不必要的重量,与卫星降低重量的要求不符.文中设计了一种"散热帽"结构,使用Flotherm软件对其散热效果进行了仿真,并对其结构尺寸进行了优化设计,给出了散热帽结构可以有效散热的结论.通过对比分析散热帽结构和常见散热结构的重量,得出了散热帽结构可以有效减重的结论.     

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.     

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。     

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....     

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.