浅谈CTE及其对FC—BGA焊点可靠性的影响

PCB对封装行业来说,最关键的莫过不同元器件和PCB之间的热膨胀系数（CTE）匹配性问题。其中FCRGA封装,通过倒装芯片实现芯片焊料凸点与FCBGA基板的直接连接,在FCBGA类产品中可实现较高的封装密度,获得更优良的电性能和热性能。但由于PCB与芯片之间cTE的不匹配,而导致FCBGA焊点的可靠性问题。本文就CTE影响FCBGA焊点可靠性展开讨论。     

LEO短数据通信小卫星天线系统设计

本文主要针对 LEO小卫星低速率数据通信的应用 ,从系统的角度提出对卫星天线和地面终端天线的设计要求 ,分析了卫星天线采用赋形方向图对通信系统性能的影响     

一种基于相位信息的图像对称性检测方法

本文介绍一种新的检测图像对称性的方法。它使用原始图像的相位信息,而不使用图像梯度信息。由于相位信息的稳定性和重要性,该方法具有很强的鲁棒性,不受图像亮度、对比度和旋转的影响。它能检测镜像对称性,旋转对称性和曲线对称性,不需要图像分割等任何预处理。实验结果证明了该方法的有效性和鲁棒性。     

强激光驱动器能源系统瞬态特征实时测控系统研究

随着惯性约束核聚变研究的发展．强激光驱动器能源系统的研究备受关注。为了向激光驱动能源系统传输效率的研究提供可靠的实验数据．研究了强激光驱动器能源系统中氙灯瞬态放电特征数据进行实时检测的方法和测控系统结构。采用量化传输模式进行特征量的检测与传输，既实现了高压隔离，又避免了在远距离传输过程中受到干扰，确保测量精度。配合系统的模块化设计，采用多线程工作模式，对计算机系统的控制功能进行工作线程划分，提高了系统的实时性和协调性。实验表明，系统有效地实现了弱电系统对强电系统的远程控制．测量精度满足测量要求，已成功应用于能源系统的实验研究。     

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??Deep shale gas reservoirs buried underground with depth being more than 3 500 m are characterized by high in-situ stress, large horizontal stress difference, complex distribution of bedding and natural cracks, and strong rock plasticity. Thus, during hydraulic fracturing, these reservoirs often reveal difficult fracture extension, low fracture complexity, low stimulated reservoir volume (SRV), low conductivity and fast decline, which hinder greatly the economic and effective development of deep shale gas. In this paper, a specific and feasible technique of volume fracturing of deep shale gas horizontal wells is presented. In addition to planar perforation, multi-scale fracturing, full-scale fracture filling, and control over extension of high-angle natural fractures, some supporting techniques are proposed, including multi-stage alternate injection (of acid fluid, slick water and gel) and the mixed- and small-grained proppant to be injected with variable viscosity and displacement. These techniques help to increase the effective stimulated reservoir volume (ESRV) for deep gas production. Some of the techniques have been successfully used in the fracturing of deep shale gas horizontal wells in Yongchuan, Weiyuan and southern Jiaoshiba blocks in the Sichuan Basin. As a result, Wells YY1HF and WY1HF yielded initially 14.1×104 m3/d and 17.5×104 m3/d after fracturing. The volume fracturing of deep shale gas horizontal well is meaningful in achieving the productivity of 50×108 m3 gas from the interval of 3 500–4 000 m in Phase II development of Fuling and also in commercial production of huge shale gas resources at a vertical depth of less than 6 000 m.     

早始新世极热气候时期湖盆水体性质及生烃环境——以东营凹陷古近系孔店组为例

早始新世极热气候（IETM）事件严重影响了海洋和湖泊的水体性质和生物活动。依据钻井岩心、元素分析、有机碳同位素与有机碳含量等实验结果,研究了东营断陷湖盆早始新世时期的湖泊水体氧化还原变化和古生产力条件,发现湖盆早期出现了较强的还原性,之后逐步恢复其氧化性。极热气候事件引起的湖水氧化还原界面的波动变化改变了其氧化还原格局,造成氧化还原环境与湖水深度变化的“不协调性”。湖盆早期具有较高的生产力,随后迅速降低之后逐渐增高,生产力的最低时期与极热气候（IETM）事件发生时期比较一致。由此证实了湖泊的时空波动演化经历了古新世-始新世时期的极热气候（IETM）事件,该事件具有明显的沉积记录和生物地球化学响应,决定了原始湖盆的水体氧化还原性质和生命活动过程,改变了整个湖盆的氧化还原结构。极热气候引起的湖水缺氧咸化造成了湖泊生产力的短暂降低,而随着恢复期的增氧作用的加强,生产力得到了极大的恢复,尤其是沙河街组四段有机碳含量较高,具有较高的生产力,成为主要的生油层和致密油气产层。     

STN—LCD的新进展

STN-LCD采用新的取向层,消除了残象;采用新的驱动波形,消除了串扰;采用二(口恶)烷、卤化物、链烯基、醚和二苯乙炔,改进了液晶料材的性能,使STN-LCD获得高的对比度、快的响应速度、低的驱动电压;采用有源矩阵驱动方法,消除了帧响应,使STN-LCD获得高的对比度、高的亮度及视频响应速度;使用温度跟踪电路,自动跟踪STN-LCD的阀值电压,使STN-LCD获得宽的工作温度。     

一种适于ATM网络的视频编码技术

本文提出了一种基于子带编码的可变比特率分层编码新算法。它能充分发挥ATM网络传输的特点,并对信元丢失这一ATM网络的固有缺陷造成的图像质量的下降进行有效的补偿,从而实现高质量的稳定的视频通信。文中给出了编码算法、信元构成的方法以及计算机模拟结果。     

砷化镓共面波导内部微波信号的电光取样检测

本文报道了共轴反射式电光取样系统。该系统时间分辨率不低于20ps,空间分辨率不低于3m。用它检测了砷化镓共面波导内部的微波信号。这套系统将被应用于砷化镓高速集成电路内部特性的在片检测。     

Design of pseudo-ternary and quaternary alloys by superlattices consisting of (zn,cd)(s,se) binary ii–vi compounds

Theoretical design of pseudo-ternary and quaternary alloys by superlattice structures consisting of (Zn,Cd)(S,Se) binary II–VI compounds has been studied. For pseudo-ternary ZnCdS and ZnCdSe alloys, the superlattices with two layers in a cycle, i.e., ZnS/CdS and ZnSe/CdSe are considered, and for pseudo-quaternary ZnCdSSe alloy, the two superlattice structures with more than two layers in a cycle are considered. In order to design and evaluate these superlattices, the expression for the equilibrium in-plane lattice constant of these superlattices has been derived by minimizing the total elastic strain energy in the cycle. The combinations of layer thicknesses in a cycle and the effective bandgap of these superlattices have been calculated while the elastic strain effect was included. The usefulness of these superlattice structures has been evaluated.