Reliability enhancement by integrated liquid cooling in power IGBT modules for hybrid and electric vehicles

Insulated Gate Bipolar Transistor (IGBT) modules in power train system of Hybrid and Electric Vehicles (HEV/EV) are working in harsh environment and high reliability and long lifetime are required. In this work, reliability enhancement by integrated liquid cooling structure in HEV/EV IGBT module is investigated. The thermal resistance of junction to heat sink can be reduced more than 50% by direct liquid cooling as eliminating thermal grease layer, so both active and passive temperature swings decrease significantly which will enhance module reliability and lifetime. The lifetime of modules with conventional and integrated liquid cooling structures are estimated under mission of standard driving cycles. We found that lifetime is prolonged obviously by direct cooling pin–fin base plate, and the compact module also makes the application power system simple and reliable.     

复杂电磁环境下的T/R组件设计

为使高频高速大功率收发(T/R)组件在复杂电磁环境下可靠稳定工作,本文对组件的开关控制、组件电源与地、组件布局与屏蔽等进行分析,提出了注意要点,并给出了设计方法。在T/R组件开关控制设计中,通过一对延迟与共轭延迟电路保证收发时间长于驱动开关时间,解决共模干扰问题;通过脉宽检测及最高切换速度约束,解决差模干扰问题;在组件电源与地的分析中,着重强调了接地间距不超过信号波长的1/20。在布局与屏蔽的设计中,着重分析了腔体谐振波长。文中给出了实例模块,并就上述3点设计要点进行了对照分析,达到在复杂电磁环境下T/R组件稳定可靠工作的目的。     

微小通道液冷冷板散热性能分析

微小通道液冷技术作为一种新型高效热控技术,利用流动与传热的微尺度效应,可以极大地提高内部流动的对流换热能力。采用冷板流道内嵌矩形微小型肋片群形成微小通道液冷流道结构,针对不同肋片参数的微小通道液冷冷板散热性能进行分析,并针对流道结构进行优化分析,分析表明,微小通道液冷冷板极限散热能力随着肋片尺寸的下降而提高,典型微小通道冷板散热能力达到常规蛇形通道冷板的4倍以上,并成功应用于某型数字阵列模块冷却,效果良好。     

Prüfer and Morita Hulls of FCP Extensions

We examine in this paper some properties of Morita and Prüfer hulls of FCP and FIP extensions of rings. Dichotomy phenomena appear in the case of a quasi-local base ring. In the general case, we define relative supports that allow us to introduce the concept of direct factorization of an extension and to characterize these hulls.     

Cohen–Macaulayness and Limit Behavior of Depth for Powers of Cover Ideals

Let 𝕂 be a field, and let R = 𝕂[x ₁,…, x _n ] be the polynomial ring over 𝕂 in n indeterminates x ₁,…, x _n . Let G be a graph with vertex-set {x ₁,…, x _n }, and let J be the cover ideal of G in R. For a given positive integer k, we denote the kth symbolic power and the kth bracket power of J by J ^(k) and J ^[k], respectively. In this paper, we give necessary and sufficient conditions for R/J ^k , R/J ^(k), and R/J ^[k] to be Cohen–Macaulay. We also study the limit behavior of the depths of these rings.     

双工位FOG邦定机的设计

随着全球的LCM制造业的迅速发展,LCM专用设备已日益受到制造商的高度重视.介绍了双工位FOG邦定机的主要特点和技术指标,分析了设备的机械结构以及控制系统的硬件和软件的设计.     

T/R组件中芯片制造和使用的可靠性分析与控制

随着雷达技术的发展,采用多芯片组装T/R组件的有源相控阵雷达越来越引起人们的关注并获得广泛的应用。在多芯片组装的T/R组件中,芯片可靠性是组件可靠性的决定因素。文中在对T/R组件构成及可靠性影响因素分析的基础上,从芯片制造、转运和使用等方面对芯片可靠性的影响进行了分析,并给出了提高芯片使用可靠性的措施及建议。     

Relative T -Injective Modules and Relative T -Flat Modules

Let T be a Wakamatsu tilting module. A module M is called (n, T)-copure injective (resp. (n, T)-copure flat) if ɛ _T ¹ (N, M) = 0 (resp. Γ₁ ^T (N, M) = 0) for any module N with T-injective dimension at most n (see Definition 2.2). In this paper, it is shown that M is (n, T)-copure injective if and only if M is the kernel of an I _n (T)-precover f: A → B with A ∈ Prod T. Also, some results on Prod T-syzygies are presented. For instance, it is shown that every nth Prod T-syzygy of every module, generated by T, is (n, T)-copure injective.     

广义n-表现模

本文研究了模的投射维数与环的总体维数的计算问题.利用n-表现模的性质,得到了广义n-表现模的结构定理和右n-凝聚环的总体维数的计算方法,推广了已有的维数计算方法.     

模范畴Recollement的Koenig定理

Koenig定理描述了环的导出范畴允许recollement的一个充分必要条件.本文给出环的模范畴版本的Koenig定理及其应用.应用一是可以导出Morita等价定理,应用二是可以描述三角矩阵环与模范畴的recollement之间的密切联系.