杜瓦及热电致冷封装中的温度传感器

在对红外光电探测器及焦平面封装结构中常用的三大类若干种温度传感器的特点及关键参数等进行整理的基础上,分析了不同种类传感器的测控精度及误差特点,并对不同温区封装结构中选用温度传感器需要考虑的因素以及使用时需要注意的问题进行了详细讨论。     

Soft Core/Shell Packages for Stretchable Electronics

This paper presents materials and core/shell architectures that provide optimized mechanical properties in packages for stretchable electronic systems. Detailed experimental and theoretical studies quantitatively connect the geometries and elastic properties of the constituent materials to the overall mechanical responses of the integrated systems, with a focus on interfacial stresses, effective modulus, and maximum extent of elongation. Specific results include core/shell designs that lead to peak values of the shear and normal stresses on the skin that remain less than 10 kPa even for applied strains of up to 20%, thereby inducing minimal somatosensory perception of the device on the human skin. Additional, strain‐limiting mesh structures embedded in the shell improve mechanical robustness by protecting the active components from strains that would otherwise exceed the fracture point. Demonstrations in precommercial stretchable electronic systems illustrate the utility of these concepts.     

Thermoelectric Cooling of Heat-Loaded Electronics

Russian Microelectronics - The characteristics of cooling and thermal control systems are calculated depending on the parameters of the thermoelectric module and the heat-loaded element. The values...     

Scaling Analysis of Performance Tradeoffs in Electronics Cooling

Using the governing equations for internal fluid flow and heat transfer, scaling laws are developed to predict how the selection of a liquid or gas coolant and geometry affects the pumping power and volume requirements of heat sinks in electronics cooling applications. One of the principal outcomes of the presented scaling analysis is derivation, based on first principles, of new figure-of-merit parameters that can be used to evaluate cooling performance and guide efforts on development of new cooling fluids. The new figures-of-merits are critically compared to existing performance metrics and experimental data from the literature to emphasize the relevance and accuracy of developed scaling laws.      

Power Electronics Cooling Effectiveness Versus Thermal Inertia

Today, there is a growing trend toward power electronics integration. In most cases, this trend is technology driven and for a given application, gain in terms of cost, reliability or manufacturability are often not achieved. As manufacturing quality and stability depend strongly on the production volumes, it is difficult to setup a production line for integrated power electronics for medium to high power applications （here defined as above 200V-20kW）, where the amount of equipment sold is relatively small and the number of lost production batches before stabilizing the processes have a large impact on the final cost. However, in a medium term perspective,     

医疗电子机柜的冷却和噪声控制

医疗诊断影像设备制造商采用通用机架安装的外壳可以满足越来越复杂和精密的医疗成像系统的要求,从而可将更多精力和投资集中于成像系统本身,而不必为系统的机械外形花费太多。 CPS　Innovations最新系列PET(正电子发射断层) 成像系统就是这样做的。利用模块化方法来解决一系列运行难题,该公司成功地在单个标准电子机柜中集成了更为强大的系统。CPS销售的成像系统非常灵敏,能够提供身体新陈代谢活动的多个截面“快照”。因此,相应的电子外壳解决方案不能牺牲系统性能、耐用性或灵活性,同时还要能够保护内部组件不受热量以及灰尘的影响。 在开发最新PET成像系统时,CPSInnovations开发了一种基本的机柜配置来满足其整个诊断成像系统系列产品的需求。CPS　　Innovations需要外壳足够灵活,支持多种不同的设备配置。在研究了多种外壳解决方案后,C P SInnovations选择了38U配置的Schroff　19英寸Eurorack系列机柜。6英尺高31.5英寸深的Schroff　Eurorack机柜提供了足够的空间,可以容纳整个PET系统和数据处理子系统,同时可以方便地通过标准的房门和通道进行移动。在PET系...     

电子洁净厂房工艺冷却水和纯水管材的选择

对电子洁净厂房工艺给水不同水质要求所选用的管材进行说明。     

多级放大器噪声谱矩阵计算及在低噪声设计中应用

本文针对通信接收机噪声性能分析中广泛采用的弗里斯（Ｆｒｉｓ）公式在低噪声设计中的不足，提出了具有复相关系数的放大器Ｅｎ－Ｉｎ噪声模型的谱矩阵形式，推导了多级放大器的噪声谱矩阵计算公式。成功地解决了多级放大器噪声性能分析及低噪声设计必需的噪声参数（最佳源阻抗及最小噪声系数）计算。     

电子工业厂房冷冻水系统自由冷却节能改造

结合某电子厂房冷冻水系统实际运行状态,介绍自由冷却节能系统在现有冷冻水系统中的设计、改造、调试运行,并分析节能运行效果     

Numerical Study of Interrupted Impinging Jets for Cooling of Electronics

The objective of this paper is to present the results of a numerical investigation of the effect of flow pulsations on local, time-averaged Nusselt number of an impinging air jet. The problem was considered to provide inputs to augmenting heat transfer from electronic components. The solution is sought through the FLUENT (Version 6.0) platform. The standard k-epsiv model for turbulence equations and two-layer zonal model in wall function are used in the problem. Pressure-velocity coupling is handled using the SIMPLEC algorithm. The model is first validated against some experimental results available in the literature. A parametric study is carried out to quantify the effect of the pulsating jets. The parameters considered are (1) average jet Reynolds number (5130 < Re < 8560), (2) sine and square wave pulsations, (3) frequencies of pulsations (25 < / <400 Hz), and (4) height of impingement to jet diameter ratios (5 < H/d < 9). In the case of sine wave pulsations, the ratio of root mean square value of the amplitude to the average value (A_N) was varied from 18% to 53%. The studies are restricted to a constant wall heat flux condition. Parametric conditions for which enhancement in the time-averaged heat transfer from the surface can be expected are identified.     

Piezoelectric Fans Using Higher Flexural Modes for Electronics Cooling Applications

Piezoelectric fans are gaining in popularity as low-power-consumption and low-noise devices for the removal of heat in confined spaces. The performance of piezoelectric fans has been studied by several authors, although primarily at the fundamental resonance mode. In this article the performance of piezoelectric fans operating at the higher resonance modes is studied in detail. Experiments are performed on a number of commercially available piezoelectric fans of varying length. Both finite element modeling and experimental impedance measurements are used to demonstrate that the electromechanical energy conversion (electromechanical coupling factors) in certain modes can be greater than in the first bending mode; however, losses in the piezoceramic are also shown to be higher at those modes. The overall power consumption of the fans is also found to increase with increasing mode number. Detailed flow visualizations are also performed to understand both the transient and steady-state fluid motion around these fans. The results indicate that certain advantages of piezoelectric fan operation at higher resonance modes are offset by increased power consumption and decreased fluid flow     

Suppression of EMI and Electromagnetic Noise in Packages Using Embedded Capacitance and Miniaturized Electromagnetic Bandgap Structures With High-k Dielectrics

A novel miniaturized simple planar electromagnetic bandgap (EBG) structure is proposed. The new structure mitigates different types of electromagnetic noise in packages. The design of the new EBG structure proposed here relies on the use of high-k dielectric material (epsiv_r >100), and consists of Meander lines and patches. The Meander lines serve to provide current continuity bridges between the capacitive patches. High-k dielectric material increases the capacitance of the patches substantially in comparison to commonly used material with much lower dielectric constant. Simulation results are provided to show that using the proposed EBG, it is possible to obtain a very wide stop band (~ 10 GHz) which covers the operating frequency of current processors and a wide range of the resonant frequencies of a typical package. The wideband is obtained using a unit cell of less than 2 mm.     

PCB-Integrated Heat Exchanger for Cooling Electronics Using Microchannels Fabricated With the Direct-Write Method

The electronic industry has a growing need for efficient heat dissipation mechanisms such as micro heat exchanger systems. This active cooling approach requires the integration of microfluidic components near the main heat sources of the electronic devices. Despite the investigation of several micro-cooling configurations, their commercial utilization by the electronic industry is rather limited due to complex fabrication and integration methods. Here, we present the integration of cylindrical microchannels fabricated by direct-write assembly in printed circuit board layouts for a micro heat exchanger application. The thermal performance of the manufactured prototype was characterized with respect to the fluid flow rate. The original fabrication and integration approaches presented here show high potential for efficient, compact, and low-cost micro heat exchangers for the electronic industry.      

基于CFD软件的电力电子设备强制风冷散热的数值模拟

随着电力电子技术的发展,对电力电子设备散热问题的研究日益重要。该文运用CFD软件对电力电子设备的强制风冷散热进行数值模拟研究,得出简单可行的散热方案,为设备的散热设计提供一定的依据,提高设备的可靠性。     

Packages go vertical

Stacking different chips in a package tucks a complete system into implantable devices like hearing aids. In this paper, the author describes how cell phones and wearable computers could be next     

Heat Pipe Integrated in Direct Bonded Copper (DBC) Technology for Cooling of Power Electronics Packaging

Thermal dissipation in power electronics systems is becoming an extremely important issue with the continuous growth of power density in their components. The primary cause of failure in this equipment is excessive temperatures in the critical components, such as semiconductors and transformers. This problem is particularly important in power electronic systems for space applications. These systems are usually housed in completely sealed enclosures for safety reasons. The effective management of heat removal from a sealed enclosure poses a major thermal-design challenge since the cooling of these systems primarily rely on natural convection. In this context, the presented paper treats the heat pipes as effective heat transfer devices that can be used to raise the thermal conductive path in order to spread a concentrated heat source over a larger surface area. As a result, the high heat flux at the heat source can be reduced to a smaller and manageable level that can be dissipated through conventional cooling methods. The objective of our work is to describe the feasibility of a cooling system with miniature heat pipes embedded in a direct bonded copper (DBC) structure. The advantage of this type of heat pipe is the possibility for implementation of the component layout on the heat pipe itself, which eliminates the existence of a thermal interface between the device and the cooling system     

军用强迫风冷加固计算机噪声影响因素研究

以某强迫风冷军用加固计算机为研究对象,对加固计算机的噪声源、噪声特性及影响噪声的主要因素进行了实验研究.研究结果表明:影响强迫风冷军用加固计算机声学噪声特性的因素主要包括风机、机箱风道,同时也排除了风机罩对计算机声学噪声特性的影响,并提出各主要影响因素对整机声学噪声贡献的占比,为将来进一步控制强迫风冷军用加固计算机声学噪声指明了方向.     

电视发射机风冷系统的滤尘和噪声控制

本文根据重庆电视发射台改造３０ｋＷ分米波电视妆射风冷系统的成功经验，介绍了空气净化和噪声控制等方面的问题。