基于弹塑性区间有限元的边坡稳定性分析

区间分析法是工程中对不确定问题进行分析的方法之一。现有区间分析法大多采用区间参数摄动法求解,其存在明显的局限性,特别对于弹塑性问题需采用增量法计算时,很难得到有效的解答。在边坡稳定性计算中采用区间变量来描述工程中的不确定性,将区间数学与弹塑性有限元相结合,建立了弹塑性区间有限元,推导了基于弹塑性区间有限元方法的边坡稳定性区间安全系数计算公式,这一方法能有效的避免区间参数摄动法的局限性。通过工程实例,验证了该方法的可行性和有效性。在此基础上探讨了岩土体参数对区间安全系数的影响。结果表明,内摩擦角对边坡安全系数的影响明显,重度、黏聚力影响较大,弹性模量和泊松比影响小。     

CMOS图像传感器的多斜率积分线性恢复方法

针对CMOS(Complementary Metal Oxide Semiconductor)图像传感器成像系统中普遍存在的动态范围小和响应线性度差的问题,提出了一种兼顾图像传感器动态范围及响应线性度的方法——多斜率积分线性恢复.该方法在固定复位电压值的多斜率积分基础上,通过测得传感器的分段响应临界值,得出分段响应与线性响应映射关系,根据该映射关系对实测图像数据进行线性恢复.通过采用具体成像系统,对比使用该方法前后的成像质量和直方图统计后得出:不同的分段积分参数对线性恢复的影响不同,在合适的参数下,该方法能够有效地提高CMOS图像传感器的动态范围及响应线性度.     

基于倾斜换能器的高性能声表面波滤波器设计

基于倾斜换能器结构,采用112°XY-LiTaO3基片材料,加入群延时波动优化。同时对器件孔径、膜厚、占空比、换能器、反射器的波长及指对数进行优化,得到通带波动小于0.2dB,群延时波动小于22ns,矩形系数小于1.6的高性能声表面波滤波器。该文研制的器件具有通带平坦,群延时波动小和矩形度高等特点,有很好的实用性。     

内蒙古东部得耳布尔铅锌矿床地质特征、控矿因素及找矿方向

得耳布尔铅锌矿床属于典型的陆相火山-次火山热液矿床。通过对得耳布尔铅锌矿床地质特征的总结,分析了该矿床的控矿因素,提出正长斑岩体是矿床成矿地质作用的实物载体;次级断裂和地堑内部之间的弧形断裂或弧形断裂与次级断裂交汇部位为矿体提供了赋存的空间位置;铅锌银多金属成矿与上侏罗统塔木兰沟组地层密切相关,矿体形态、产状受构造控制明显,并指出寻找陆相火山-次火山热液型矿床的重要部位为经历了火山喷发、浅成岩浆就位产生的一系列环状、放射状断裂系统、破碎带、裂隙带等。     

AC impedance modelling study on porous electrodes of proton exchange membrane fuel cells using an agglomerate model

A one-dimensional model of the PEM fuel cell cathode is developed to analyse ac impedance spectra and polarisation curves. The porous gas diffusion electrode is assumed to consist of a network of dispersed catalyst (Pt/C) forming spherically shaped agglomerated zones that are filled with electrolyte. The coupled differential equation system describes: ternary gas diffusion in the backing (O₂,N₂${\text{O}}_2\text{,}{\text{N}}_2$, water vapour), Fickian diffusion and Tafel kinetics for the oxygen reduction reaction (ORR) inside the agglomerates, proton migration with ohmic losses and double-layer charging in the electrode. Measurements are made of a temperature-controlled fuel cell with a geometric area of 1.4 cm ×$\times$ 1.4 cm. Lateral homogeneity is ensured by using a high stoichiometry of _λmin${\lambda }_{\text{min}}$. The model predicts the behaviour of measured polarisation curves and impedance spectra. It is found that a better humidification of the electrode leads to a higher volumetric double-layer capacity. The catalyst layer resistance shows the same behaviour depending on the humidification as the membrane resistance. Model parameters, e.g. Tafel slope, ionic resistance and agglomerate radius are varied. A sensitivity analysis of the model parameters is conducted.     

Development of Finite Element Limiting Analysis Method and Its Applications in Geotechnical Engineering

The Finite Element Limiting Analysis Method (LELAM) has the advantage of combining a numerical analysis method with traditional limiting equilibrium methods. It is particularly applicable to the analysis and design of geotechnical engineering. In the early 20th century,FELAM has been developed vigorously in domestic geotechnical engineering over international common finite element procedures. It has made great achievements in basic theory research and computational precision, thus broadening the application fields in practical projects. In order to gradually make innovations in geotechnical design methods, some of our research results are presented, mainly including geotechnical safety factor definitions, the principles for use of the method concerned, the overall failure criterion, the deduction and selection of the yield criterion, and the measurement to improve the computational precision, etc..The application field has been broadened from twodimensional to threedimensional, from soil slope to jointed rock slope and foundation, from stable seepage to nonstable seepage, from slope and foundation to tunnel. This method has also been used in search of many hidden sliding surfaces of complex landslides, conducting the structural support design considering the interaction between the soil and the structure, and computing simulation foundation bearing plates load tests, etc..     

黄陵结晶岩区斜坡成因类型及稳定性评价

本文通过对长江三峡黄陵结晶岩区的地质条件、斜坡分级、各类斜坡的分布特征及成因类型等方面的系统论述，综合评价结晶岩区各类斜坡的宏观稳定性与稳定性分区，从而达到对该区斜坡合理开发与综合利用的目的。     

城门山铜矿湖泥边坡稳定性分析

介绍了城门山铜矿矿区表层约30m厚的湖泥分层及其土体物理力学性质，用二维变分法计算分析湖泥边坡的稳定性，并提出合理边坡角。     

三峡库区巫山新县城北门坡变形体形成机制与稳定性分析

简要介绍了三峡库区巫山新县城北门坡变形体的地质环境，分析了变形体的形成机制，对其稳定性进行了计算和评价。