Intact soft clay’s critical response to dynamic stress paths on different combinations of principal stress orientation

Comprehensive tests on Hangzhou intact soft clay were performed, which were used to obtain the soils’ critical response to undrained dynamic stress paths under different combinations of principal stress orientation. The different combinations included cyclic principal stress rotation (CPSR for short), cyclic shear with abrupt change of principal stress orientation (CAPSO for short) and cyclic shear with fixed principal stress orientation (CFPSO for short). On one side, under all these stress paths, samples have obvious strain inflection points and shear bands, and the excess pore water pressure is far from the level of initial effective confining pressure at failure. Stress paths of major principal stress orientation (α) alternating from negative and positive have quite different influence on soil’s properties with those in which α is kept negative or positive. On the other side, due to the soil’s strongly initial anisotropy, samples under double-amplitudes CPSR and CAPSO (or single-amplitude CPSR and CFPSO) have similar properties on dynamic shear strength and pore water pressure development tendency when α is kept within ±45°, while have quite different properties when α oversteps ±45°.     

解读连战先生的民族情

文章试图从两方面解读连战先生深厚的民族情.这种民族情一方面来源于他的家族,连战的先祖到台湾死也不臣服清,曾祖父至父亲三代以各种形式坚持抗日及父母对他言传身教;另一方面与他早年在祖国大陆的生活经历有关,从他对抗战和日本的态度及祖国大陆寻踪等方面体现出来.     

Evaluation of ultimate bearing capacity of Y-shaped vibro-pile

Based on Mindlin stress solution, a numerical computational method was proposed to calculate the stresses in the ground induced by side friction and the resistance of Y-shaped vibro-pile. The improved Terzaghi’s and ЪерезанцевВГ’s methods for ultimate bearing capacity evaluation were proposed by considering the stress strength induced by friction resistance at pile head level of Y-pile. A new method to calculate the ultimate bearing capacity of Y-pile was also proposed based on the assumptions of soil failure mode at the tip of Y-pile and the use of Mohr-Coulomb soil yield criterion and Vesic compressive correction coefficient with the induced stresses in the ground. Based on the comparisons with the field static load test results, it is found that the improved Terzaghi’s method gives higher ultimate capacity, while the other two methods shows good agreement with the field results.     

Adhesion coefficient of automobile tire and road surface

The adhesion coefficient of automobile tire and road surface was analyzed and the formula about it was derived.Some suggestions about highway construction,driving safety of the drivers and the judgment of the traffic accidents were presented.The results show that the adhesion coefficient is a function with the extreme value.If there is atmospheric pressure in the tire,the load of the vehicle and the degree of the coarse on the road surface is not selected properly,it will reach the least and affect the safety of the running automobile.     

Effects of stress conditions on rheological properties of granular soil in large triaxial rheology laboratory tests

In order to study the rheological properties of red stone granular soil,a series of rheological experiments were executed on large tri-axial rheological apparatus.Under 100,200 and 300 kPa confining stress conditions,the rheological tests were carried out.These experiment results showed that the stress conditions,especially the stress level were the critical influencing factors of the rheological deformation properties.Under the low stress level(S=0.1),the granular soil showed the elastic properties,and there was no obvious rheological deformation.Under the middle stress level(0.20.8) creep curves showed the non-linear viscous plastic rheological properties.Especially,under the stress level of S=1.0,the accelerated rheological phase of creep curves occurred at early time with a trend of failure.The stress level had obvious effects on the final rheological deformation of the soil sample,and the final rheological deformation increments nonlinearly increased with stress level.The final rheological deformation increment and step was little under low stress level,while it became large under high stress level,which showed the nonlinearly rheological properties of the granular soil.The confining pressure also had direct effects on final rheological deformation,and the final rheological deformation linearly increased with confining pressure increments.     

2008年我国房地产业的发展模式与市场把握

在深入市场调查、认真采集数据和科学分析研究的基础上,从我国新一年房地产业发展的"背景和环境"、"预期和责任"、"风险和影响"、"保障和创新"等方面进行阐述和论证.     

窃取商业秘密获得的专利权归商业秘密权利人所有——兼谈商业秘密构成要件和范围

中国加入WTO以后,知识产权的保护意识日益强化,作为知识产权范畴的专利权更是被人们普遍关注和重视.以"错案"为研究对象,运用商业秘密的有关理论以及保护商业秘密和专利权的有关法律制度,特别是从窃取商业秘密获得的专利权归谁所有的角度,对人民法院的判决进行了分析研究,指出了人民法院的判决是错误的,提出了窃取商业秘密获得的专利权归商业秘密权利人所有.这有利于人民法院公正司法,依法审判.     

从语气助词的角度浅析日语表达方式的特性

日语中有着十分丰富的语气助词,其虽然不具有实际的意义,然而通过语气助词,却能够流露出说话者的心情和感受,传递出不溢于言表的隐性含义,在日常的表达中扮演着十分重要的角色.从语气助词的角度,分析总结日语在表达上所具有的特性.     

Additional water use influencing strength and fluidity of recycled concrete

Through adding different additional water use,the compressive strength,splitting tensile strength and fluidity of recycled concrete of three aggregate combination forms were studied by experiment respectively.The experimental results show that with the increase of adding additional water use,the compressive strength and splitting tensile strength of recycled coarse aggregate concrete decrease,but that of recycled fine aggregate concrete and recycled all aggregate concrete increase firstly then decrease.When additional water use is added more 15% or 20% than that of basic ordinary concrete,the recycled coarse aggregate concrete and fine one can get pretty good fluidity.When it is added more 30%,the recycled all aggregate concrete has fluidity that is just satisfied.     

情趣与意象的契合——《逢雪宿芙蓉山主人》与《雪夜林边驻脚》之比较

通过分析《逢雪宿芙蓉山主人》与《雪夜林边驻脚》两诗的情趣和意象,发现两诗都采用了大致相似的意象.但由于诗人各自的文化传统的差异,在两诗中所传达的情趣却不同.然而,正是由于两诗各自在情趣与意象上的契合,才创造出了各自完美的诗境.     

密度梯度曲线的设计和配制

本文从理论上证明得出、当重、轻混合液的体积相同时,并且重混合液的流速为轻混合液的流速的二倍时,从重混合液中流出的比重就是密度管高度的线性函数。     

整流器对天然气管道内计量段流动影响的数值模拟

天然气计量准确度受管内流场影响大。首次采用数值模拟方法,以加带扩散管的管路为例,对其在加装不同整流器时的管内流场进行计算。计算结果表明,扩散段引起的流动不均匀区域延伸至下游17倍管径左右,整流器作用明显,加板式整流器和管式整流器后,管内主流速度在整流器下游恢复均匀稳定的距离依次为12倍直径和6倍直径左右。研究结论对于流量计的选择、现场安装具有指导作用,为提高天然气计量准确度的研究提供了一种新的方法。     

Multi-robot task allocation for exploration

The problem of allocating a number of exploration tasks to a team of mobile robots in dynamic environments was studied. The team mission is to visit several distributed targets. The path cost of target is proportional to the distance that a robot has to move to visit the target. The team objective is to minimize the average path cost of target over all targets. Finding an optimal allocation is strongly NP-hard. The proposed algorithm can produce a near-optimal solution to it. The allocation can be cast in terms of a multi-round single-item auction by which robots bid on targets. In each auction round, one target is assigned to a robot that produces the lowest path cost of the target. The allocated targets form a forest where each tree corresponds a robot＇s exploring targets set. Each robot constructs an exploring path through depth-first search in its target tree. The time complexity of the proposed algorithm is polynomial. Simulation experiments show that the allocating method is valid.     

船后吊舱推进器的水动力性能研究

为了分析船体形状对吊舱推进器的影响,研究了船后伴流中吊舱推进器的水动力性能.船后伴流用计算流体力学方法进行分析,吊舱推进器的水动力性能用面元法研究,吊舱和螺旋桨的相互影响用迭代方法求解,用蒙瑞诺解析公式计算螺旋桨和吊舱之间的诱导速度,结合船尾伴流的计算结果分析船尾伴流中吊舱推进器的水动力性能,并对船后不同位置吊舱推进器的水动力性能进行了比较.研究认为,船尾伴流会降低吊舱推进器的效率,吊舱推进器距离船体越远,效率越高.     

2D数字压力阀

2D数字压力阀是采用阀芯的双运动自由度设计的导控型压力阀。该阀由阻尼管型的液压桥路和旋转自由度构成阀的导控级 ,控制着一个阀腔的压力 ,该压力与反馈到另一个阀腔的压力进行比较 ,所产生的不平衡力驱动阀芯线性运动从而改变阀口的大小 ,使的阀的出口压力与液压桥路的输出压力保持定值比例关系 ,并且不随阀口输出流量的变化而变化。阀芯的旋转运动由数字接口驱动 ,该数字接口由执行元件——步进电动机及数字阀控制器组成。控制器的核心部分为跟踪算法 ,该算法可以使步进电动机的输出角位移连续可控 ,这样可以同时保证阀的响应速度和控制精度     

银膜超级透镜成像原理研究

从Pendry的超级透镜成像理论出发,阐述了s光和p光入射情形的物像关系,推导了金属银膜作为超级透镜的条件,分析了消逝波和行波成分的成像特性,导出了近场条件下金属银膜超级透镜消逝波透射公式.利用Nicholas等报告的实验数据对其进行验证,得到透过率与横向波矢和银膜厚度的关系,并讨论了对于不同尺寸物体成像时的金属银膜厚度最佳值.研究结果表明,银膜超级透镜可以使成像质量大大改善.     

试论高职教育与终身教育的关系

职业教育是终身教育的内在组成部分。终身教育为高职教育提供可持续的广阔空间；高职教育为终身教育提供学习场所。高职教育“关键能力”的培养为终身教育打下坚实的基础。     

高速投射物对生物致伤时瞬时空腔的理论研究

分析计算了高速投射物对生物体致伤时肌肉组织中瞬时空腔的发展过程 ;通过将肌肉组织简化为不可压缩的Voigt Kelvin粘弹性流体模型 ,在球对称和纯径向运动的假设条件下 ,应用非牛顿流体力学的基本方程建立了一种计算瞬时空腔发展的理论模型 ;该模型能较好地反映肌肉组织中瞬时空腔的脉动发展过程以及瞬时空腔内压力的变化 ,计算结果同实验结果基本一致 ;通过该理论模型 ,可以对瞬时空腔进行定量的理论分析和研究 .     

预张力悬索桥及其静力学性能分析

为从理论上获得预张力悬索桥的力学特性,利用大位移不完全广义势能变分原理,建立了预张力悬索桥的一般基础微分方程.在进一步引入假设条件下,导出了基于古典挠度理论的平衡微分方程.通过对微分方程的解析,讨论了预张力悬索桥的静力学特性及其与普通悬索桥的区别.结合算例悬索桥的数值分析表明,预张力悬索桥由于抗风索的存在,以及结构中建立的预张力,在提高结构刚度、减小加劲梁弯矩等方面具有一定的优越性.     

钻孔摄像测试围岩松动圈的机理与实践

利用全景钻孔数字摄像技术和数字图像处理与分析方法,研制了全景数字钻孔摄像煤矿巷道围岩松动圈测试系统,该系统由硬件和软件2大部分组成,硬件系统包括高压密封摄像定位磁性罗盘以及微型CCD摄像机等,软件系统则包括钻孔图像实时监视与实时处理(如图像无缝拼接、平面图展开、三维钻孔岩芯生成)以及松动圈的分析程序.在松动圈识别关键技术中,提出了用钻孔图像中围岩裂缝的圆形度指标作为判断围岩松动圈标准的新思路.首次将其应用于山东七五煤矿深井围岩松动圈的测试工作,获得了围岩松动圈厚度值在巷道断面不同部位有较大差异的分布规律,并和传统的围岩松动圈超声波测量法比较,误差在3.5%之内,验证了钻孔摄像技术测量松动圈的可靠性,为高应力地下工程围岩松动圈厚度值的测试提供了新的方法.