浅谈十万立储罐倒装法施工工艺

目前很多大型储罐施工为正装法,高空作业频率高,安全风险大,而且受到气候影响很大。大型储罐倒装法施工能够保证安全和进度。     

大型储罐内边群抱倒装法施工技术及应用

本文主要叙述了采用内边群抱倒装法进行立式储罐施工技术的应用,适用性更强,技术、经济效果显著。     

无铅互连凸点电迁移失效的四探针测量

针对无铅互连电迁移失效这一高密度封装时面临的重要课题进行了研究.采用四探针法分别监测了电流密度为1.5×104 A/cm2和2.2×104 A/cm2时Sn3.5Ag0.5Cu互连凸点上电压的变化,发现电流密度为2.2×104 A/cm2时凸点的平均电阻变化率超过电迁移失效的临界值10 %,分析了其微观结构的扫描电镜照片,所提出的发生电迁移失效的电流密度值为凸点设计提供十分有用的数据.对无铅互连凸点的电迁移失效过程和四探针测量法的测量误差进行了分析,提出了采用四凸点结构提高测量精度的改进措施.     

半刚性基层沥青路面倒装结构在云南省农村公路中的应用

针对云南省农村公路半刚性基层沥青路面容易产生裂缝的问题,在对云南省特别是昆明市西山区农村公路调研和分析的基础上,提出了半刚性基层沥青路面倒装结构。分析了该路面类型能够防治裂缝的机理,并阐述了其施工技术,为其他地区修建此路面结构提供一点经验。     

科技英语倒装句初探

文章从语法倒装和修辞倒装两大类详细阐述倒装的一些基本规律及其用法。     

超声激振的倒装芯片焊球缺陷检测方法研究

针对倒装芯片内部焊球缺陷难以检测的问题,提出了基于声固多物理场耦合的超声激振检测方法．首先,建立倒装芯片超声激振检测仿真模型,模拟了含有典型缺陷(缺球和虚焊)的倒装芯片在超声激励下的振动响应,仿真结果显示焊球缺失和虚焊会引起倒装芯片振动速度的明显变化;其次,搭建超声激振倒装芯片检测系统,对倒装芯片进行检测,获取含不同缺陷倒装芯片的实际振动信号;最后,利用核主成分分析算法改进多粒度级联森林网络,对含典型缺陷的倒装芯片振动信号进行识别与分类．仿真和实验结果验证了基于多粒度级联森林网络和超声激振技术检测倒装芯片焊球缺陷的有效性．     

提高LED光提取效率的研究

通过模拟计算的方法分析了倒装结构LED中衬底材料折射率及厚度对光提取效率的影响,并在此基础上提出一种新的菱形结构.结果表明:该菱形结构可大幅度提高LED光提取效率,在使用Si、蓝宝石、SiC作为芯片衬底材料时,菱形结构的光提取效率分别提高到传统方形结构的1.51、2.03、3.65倍.     

High power and high reliability GaN/InGaN flip-chip light-emitting diodes

High-power and high-reliability GaN/InGaN flip-chip light-emitting diodes (FCLEDs) have been demonstrated by employing a flip-chip design, and its fabrication process is developed. FCLED is composed of a LED die and a submount which is integrated with circuits to protect the LED from electrostatic discharge (ESD) damage. The LED die is flip-chip soldered to the submount, and light is extracted through the transparent sapphire substrate instead of an absorbing Ni/Au contact layer as in conventional GaN/InGaN LED epitaxial designs. The optical and electrical characteristics of the FCLED are presented. According to ESD IEC61000-4-2 standard (human body model), the FCLEDs tolerated at least 10\,kV ESD shock have ten times more capacity than conventional GaN/InGaN LEDs. It is shown that the light output from the FCLEDs at forward current 350mA with a forward voltage of 3.3\,V is 144.68\,mW, and 236.59\,mW at 1.0\,A of forward current. With employing an optimized contact scheme the FCLEDs can easily operate up to 1.0\,A without significant power degradation or failure. The life test of FCLEDs is performed at forward current of 200\,mA at room temperature. The degradation of the light output power is no more than 9\% after 1010.75\,h of life test, indicating the excellent reliability. FCLEDs can be used in practice where high power and high reliability are necessary, and allow designs with a reduced number of LEDs.     

Anomalous Kondo-Switching Effect of a Spin-Flip Quantum Dot Embedded in an Aharonov-Bohm Ring

We theoretically investigate the Kondo effect of a quantum dot embedded in a mesoscopic Aharonov-Bohm （AIR） ring in the presence of the spin flip processes by means of the one-impurity Anderson Hamiltonian. Based on the slave-boson mean-field theory, we find that in this system the persistent current （PC） sensitively depends on the parity and size of the AB ring and can be tuned by the spin-flip scattering （R）. In the small AB ring, the PC is suppressed due to the enhancing R weakening the Kondo resonance. On the contrary, in the large AB ring, with R increasing, the peak of PC firstly moves up to max-peak and then down. Especially, the PC phase shift of π appears suddenly with the proper value of R, implying the existence of the anomalous Kondo effect in this system. Thus this system may be a carldidate for quantum switch.     

空间用GaInP/GaAs/In0.3Ga0.7 As(1 eV)倒装三结太阳电池研制

采用阶变缓冲层技术 (step-graded) 外延生长了具有更优带隙组合的倒装GaInP/GaAs/In_0.3Ga_0.7As(1.0 eV) 三结太阳电池材料, TEM和HRXRD测试表明晶格失配度为2%的In_0.3Ga_0.7As 底电池具有较低的穿透位错密度和较高的晶体质量, 达到太阳电池的制备要求. 通过键合、剥离等工艺制备了太阳电池芯片. 面积为 10.922 cm² 的太阳电池芯片在空间光谱条件下转换效率达到32.64% (AM0, 25 ℃), 比传统晶格匹配的 GaInP/GaAs/Ge(0.67 eV) 三结太阳电池的转换效率提高3个百分点. 关键词： 太阳电池 三结 倒装结构