小湾水电站高水位运行下拱坝和坝肩边坡稳定性分析

基于却荷岩体力学理论和方法,采用大型岩土工程数值分析软件(FLAC3 D ),对小湾水电站高水位运行大坝与边坡相互作用进行了研究,建立了其坝肩边坡和拱坝三维有限元模型。根据施工过程,在初始工况、开挖工况、却荷工况、加固工况基础上,考虑了正常蓄水位情况时拱端推力、坝肩边坡的应力和位移变化规律,并与其监测值进行了对比。结果表明计算值与监测值十分吻合,论证了坝体设计的合理性,为小湾水电站高水位安全运营提供了一定的参考依据。     

Self-adaptive learning based immune algorithm

A self-adaptive learning based immune algorithm (SALIA) is proposed to tackle diverse optimization problems, such as complex multi-modal and ill-conditioned problems with the high robustness. The SALIA algorithm adopted a mutation strategy pool which consists of four effective mutation strategies to generate new antibodies. A self-adaptive learning framework is implemented to select the mutation strategies by learning from their previous performances in generating promising solutions. Twenty-six state-of-the-art optimization problems with different characteristics, such as uni-modality, multi-modality, rotation, ill-condition, mis-scale and noise, are used to verify the validity of SALIA. Experimental results show that the novel algorithm SALIA achieves a higher universality and robustness than clonal selection algorithms (CLONALG), and the mean error index of each test function in SALIA decreases by a factor of at least 1.0×10⁷ in average.     

以文化的视角解析美军空间军事人才培养

根据美军空间军事人才培养的现状,从空间职业化的思想文化、组织文化、制度文化和价值文化4个方面入手,分析和探讨了美军空间职业化战略、人才培养组织、职业化培养机制和人才培养目标等方面的特点,并总结归纳了指导空间军事人才培养的若干启示,为认识和探索空间人才培养问题开辟了独特的视角。     

A review of heavy-duty legged robots

Heavy-duty legged robots have been regarded as one of the important developments in the field of legged robots because of their high payload-total mass ratio, terrain adaptability, and multitasking. The problems associated with the development and use of heavy-duty legged robots have motivated researchers to conduct many important studies, covering topics related to the mechanical structure, force distribution, control strategy, energy efficiency, etc. Overall, heavy-duty legged robots have three main characteristics: greater body masses, larger body sizes, and higher payload-total mass ratios. Thus, various heavy-duty legged robots and their performances are reviewed here. This review presents the current developments with regard to heavy-duty legged robots. Also, the main characteristics of high-performance heavy-duty legged robots are determined and conclusions are drawn. Furthermore, the current research of key techniques of heavy-duty legged robots, including the mechanical structure, force distribution, control method, and power source, is described. To assess the transportation capacity of heavy-duty legged robots, performance evaluation parameters are proposed. Finally, problems that need further research are addressed.     

Calculation of alkali silica reaction (ASR) induced expansion before cracking of concrete

A calculation method for predicting the formation of alkali-silica gel and analyzing the relationship of ASR induced expansion and aggregate size was proposed. The complicated chemistry of alkali silica reaction was simplified to be controlled by the diffusion process of chemical ions into reactive aggregates. The transport of chemical ions was described by the Fick’s law. The ASR induced expansion was assumed to be directly related to the volume of produced alkali-silica gel. The finally expansion of a representative volume element (RVE) of concrete was then calculated according to the ratio of volume of alkali-silica gel and RVE. The input parameters of the model contains radius of reactive aggregate, volume fraction of reactive aggregate, initial concentration of chemical ions and porosity of cement paste. The applicability of the model was validated by an experiment of ASR-affected concrete specimens containing glass aggregate. It is shown that the amount of alkali-silica gel and ASR induced expansion can be well predicted. The expansion increasing with the decreasing aggregate size can be reproduced by the proposed model.     

一种新型宽量程气体流量标准装置的研制

针对目前气体流量标准装置测量范围度较小和喷嘴组无密封性检漏措施等问题,研制了一套基于音速喷嘴的宽量程度负压法高准确度气体流量标准装置。该装置通过选取高准确度小流量临界流文丘里喷嘴,提高影响参量(如温度、压力)的测量准确度。采用独特的气环泵及多级离心风机真空发生设备,同时借助检漏技术及Profibus现场总线技术等措施,实现了装置的高性能。验证结果表明,该标准装置测量范围度大、扩展不确定度低、被检仪表口径范围广,具有广阔的应用前景。     

模式识别方法及其在地球物理勘探中的应用

将模式识别方法应用于地球物理资料处理,近年来已引起了国内外学术界的注意。模式识别可以使我们充分利用在野外获得的资料,从中“榨取”出更多的地质信息。它不仅可能自动提取我们所需要的地球物理资料,而且还可能对所提取出来的资料自动进行“解释”。本文主要说明在用计算机进行地球物理资料的自动处理和解释时,可以把其中一些问题归结为模式识别问题,从而可以运用模式识别的许多原理和方法。文中简要介绍了统计模式识别和结构模式识别两大类方法的一般原理。较详细地介绍了用句法方法识别波形和标记的松驰算法,以及它们在地球物理资料自动处理中可能的应用。这是一个值得注意的、有价值的研究领域。     

用厚度阈值法改善深拉延冲压件坯料形状预测精度

将作者首次提出的厚度阈值法应用到基于逆有限元原理的坯料形状预测算法中,有效地改进了深拉延冲压件坯料形状预测的精度,并以某汽车油底壳拉延件为实际算例,分别用改进前和改进后的算法,对其坯料形状进行预测,预测结果与实际坯料形状的对比结果验证了本文方法的有效性。     

关于知识管理与IT企业文化改革的研究

围绕IT企业文化改革,在阐述IT企业知识文化革命的基础上,分析了知识管理对IT企业文化的影响,指出知识管理是IT企业文化改革的重要因素,倡导建立有利于知识管理的IT企业文化,强调合理地解决“才与财”的问题。     

Design of a novel chip on glass package solution for CMOS image sensor device

This paper presents a chip-on-glass (COG) package solution for CMOS image sensors based on highly precise and reliable bumping and flip-chip bonding techniques. The package is fabricated using three core techniques, namely the damage-free image sensor bumping technique, the wafer form glass substrate patterned technique, and the damage-free flip-chip bonding technique. Since the proposed package concept is new, the effects of the package geometry and material properties on the package reliability are uncertain in the initial design stage. A three-dimensional nonlinear finite element model of the proposed CMOS image sensor package is created. In the simulations, the applied thermal load is cooled from 200 °C to ambient temperature (25 °C) to model the thermal deformation and warpage of the package during the practical ACF assembly cooling process. The design parameters influencing the reliability of the package, i.e. the material properties of the ACF, the thickness of the image chip and the thickness of the optical glass are investigated. Two control levels are specified for the chip, glass, and ACF factors and a 2³ factorial design is created to determine the appropriate combination of material properties and geometric size. It is found that the glass thickness and the ACF properties significantly affect the thermal deformation of the package, while the chip and glass factors, and the interaction between them, significantly affect the warpage. Regression models are developed to perform a series of surface response simulations. Using the developed statistical tests and regression models, suitable material selection criteria and geometric sizes can be specified to satisfy various reliability considerations in the initial design stage.