地质雷达检测基坑开挖引起的地基病害

作为一种新兴的地球物理勘探方法,地质雷达在岩土工程中的应用日趋广泛.结合工程实例,开展了地质雷达检测基坑开挖引起的地基病害的应用研究.根据现场检测得到的雷达测线剖面图和单道波形图,对基坑开挖引起的土体疏松和脱空等典型地基病害进行了图像解释,并采用现场静力触探试验进行了对比验证.结果表明,地质雷达具有快速确定地基病害位置的能力,是一种较为理想的检测基坑开挖引起的地基病害的有效手段.     

The influence of the ratio of “rotational speed/traverse speed” (ω/v) on mechanical properties of AZ31 friction stir welds

The influence of different parameters such as welding pressure, rotational speed, and traverse speed on the weld properties has been evaluated earlier but there are some important parameters yet to be thoroughly investigated. In this study, an effort has been made to determine the influence of different ratios of rotational speed/traverse speed on mechanical properties of different zones of friction stir welded AZ31 magnesium alloy. Mechanical properties of different zones were determined by a shear punch test. It was found out that increasing the aforementioned ratio leads to a slight decrease in yield and ultimate strength of the stir zone and the transitional zone. It was also observed that increasing rotational/traverse speed ratio increases the weld nugget size and decreases the incomplete root penetration.     

基于有序双循环链表的低代价最短路径树快速算法

低代价最短路径树是一种广泛使用的多播树。在FLSPT算法的基础上,通过选择有序双循环链表作为待发展节点序列Q的运算与存储中心,提出了基于有序双循环链表的低代价最短路径树快速算法DKFLSPT。该算法构造的最短路径树与FLSPT算法构造的最短路径树具有相同的性能,利用有序双循环链表的局部性原理来达到改进节点路径最小值的搜索过程。随机网络模型的仿真结果表明,DKFLSPT 算法效率平均可以提高19%。     

SPT图在钻孔机扭矩-转速控制系统中的应用

在分析钻孔机钻进过程中功率消耗公式基础上,提出钻孔机智能控制的关键是转速和扭矩控制及将SIG图应用为控制依据的思想．分析了SIG图和钻孔机掘削能量消耗公式,推导出了适应岩层变化的基于SIG图的钻孔机转速-扭矩关系公式．提出了利用压差负反馈平衡阀简化钻孔机的垂直度控制思想,给出了基于SPT图的钻孔机智能控制系统流程图．     

Coupling of dielectric and mechanical relaxations with glass transition and stickiness of milk solids

Dielectric and mechanical α-relaxations of milk solids with varying milk protein contents were determined by dielectric (DEA) and dynamic-mechanical (DMA) analysis, respectively. The frequency dependence of α-relaxations occurring around and above the glass transition was modeled by the Vogel-Fulcher-Tamman (VTF) relationship. The α-relaxations were governed by the amorphous lactose and shifted to higher temperatures when protein contents of milk solids were increased at all water activities, a_w. Increasing protein contents lowered the overall molecular motions of milk solid components which were shown by small changes in dielectric and mechanical properties above the glass transition. The α-relaxations were strongly frequency-dependent. At temperatures around and above the glass transition, the primary α processes were recorded and the corresponding relaxation times were determined. The temperature dependence of the relaxation times was affected by glass transition, solid composition and water. The relaxation times decreased with increasing temperature and water content as a result of thermal and water plasticization. Higher protein contents increased the relaxation times measured for milk solids. This was associated with small changes in α-relaxation characteristics and reduced powder stickiness. Data on the compositional effects on the relaxation times of milk solids were related to flow characteristics and powder stickiness around and above the glass transition.     

Trans advanced surface laser ablation (TransPRK) outcomes using SmartPulseTechnology

Purpose

To evaluate early visual rehabilitation, post-operative pain, epithelial healing and haze after transepithelial photorefractive keratectomy (TransPRK) using the SmartPulseTechnology (SPT) of Schwind Amaris (Schwind eye-tech-solutions GmbH, Kleinostheim, Germany).

利用标准贯人试验确定粘性土的不排水抗剪强度

粘性土的不排水抗剪强度是粘性土的重要力学指标,但目前确定该指标的方法存在着取样扰动或测试深度有限的缺点.通过对马来西亚槟州第二跨海大桥的试验结果研究,综合考虑了SPT的修正方式,不排水抗剪强度的确定方法,粘性土的塑性指数等因素的影响,建立了该地区土层的Cu和SPT之间的经验关系,可为该地区或其它地区的类似工程提供参考.     

关于天然地基弹性均压系数的确定

天然地基弹性均压系数是动力机器基础设计中最为重要的参数,根据天然地基弹性均压系数的定义,对当前确定弹性均压系数的几种方法进行了分析,指出GB 50040—96《动力机器基础设计规范》和采用地基土变形模量计算成层地基的弹性均压系数的方法在理论上均是不正确的,而应采用各土层的弹性模量去确定成层地基均压系数。为了便于工程应用,给出了与GB 50040—96相应地基承载力特征值对应的弹性模量值。最后,介绍了利用剪切波波速和标准贯入试验击数确定地基土弹性模量的有关资料。     

用标准贯入击数估算钻孔灌注桩单桩极限承载力

通过对物性参数与侧阻力、端阻力关系的分析研究,建立了标贯击数与侧阻力、端阻力的经验关系式,经过分析验证,指出利用标贯击数估算单桩极限承载力可获得较高的精确度,应用到实际工程中是可行的。     

Φ700锤击沉管灌注桩的应用

本文结合实际工程介绍了Φ７００锤击沉管灌注桩在高层建筑基础工程中的应用，对该桩型在设计，施工方面的一些问题作了分析，研究，瓶一其它桩型进行了经济对比。