海面表层水温与表皮水温的相关研究

海洋水温是海洋研究的重要参数之一.本文介绍了"表皮温度"和"表层温度"的不同概念,分析了表皮和表层温度不同的产生机理,初步建立了两个温度之间的关系式,分析了回归方程产生的误差.     

四川自贡地区晚侏罗世剑龙类皮肤印痕化石新观察

重新观察了四川自贡晚侏罗世上沙溪庙组巨棘龙皮肤印痕化石。化石材料清楚地显示了巨棘龙体被鳞片。这些鳞片总体镶嵌排列成网状。大多数鳞片呈五边形,少数呈四边形或六边形。鳞片之间以沟缝相接。小鳞片中散布有少量五边形或六边形的大鳞片,每枚大鳞片被13～14枚鳞片所环绕。鳞片表面粗糙,不存在“瘤状小突”,有条索状隆突。条索状隆突可降低环境光线造成的眩光,降低鳞片表面整体亮度水平。据原始埋藏的位置和鳞片的分布推测,四川巨棘龙皮肤印痕化石的身体位置可能为前肢的肘关节及其邻近的上臂、体侧的皮肤     

Relationships Between Anomalies of Land-Sea Thermal Contrast in North Africa and Summer Flood and Drought Across the Jianghuai Region of China

The flood and drought across the Yangtze and Huaihe River(Jianghuai)areas are frequent in summer,especially in June and July.Therefore,predicting the summer flood and drought in the Jianghuai region is always one of the key topics concerned by meteorologists in China.Previous studies focused more on the skin temperature anomalies in a local area,and paid less attention to the connections between the anomalies of land-sea thermal contrast in remote continents and the summer flood and drought in Jianghuai areas of China.By using the US NCEP/NCAR monthly mean reanalysis data and the rainfall data at 743 stations in China,based on the interdecadal variation characteristics of the flood and drought index(FDI)during 51 yr(1954-2004)in the Jianghuai region of China in summer,the North African areas have been selected as the key regions for the correlation analysis.The results show that the surface temperature anomalies in the key regions have good continuity in winter,and the winter North Atlantic Oscillation(NAO)is perhaps one of the important factors that bring about the continuity of the anomalies.By a singular value decomposition(SVD)analysis between the skin temperature in the previous winter in North Africa and the summer rainfall in the Jianghuai region,it is found that when the North African continent is colder(warmer)and its northwestern sea is warmer(colder),the rainfall increases(decreases)in the Jianghuai region in summer generally.Further analysis finds that the anomaly of the surface temperature contrast between sea and land in North Africa has a good indication for the summer flood and drought in the Jianghuai areas of China.Therefore,a sea and land thermal contrast index(SLTCI)is defined to reflect the intensity of the large-scale land-sea thermal contrast.A positive correlation between the SLTCI in North Africa and the summer FDI in Jianghuai areas is identified,and it can well indicate the extreme flood and drought situations in the Jianghuai region of China.     

采用试桩验证注浆加固效果

在新回填的坑中兴建建筑物存在很多安全隐患,为提高填土密实度、均匀性和承载能力,防止地面产生过大的沉降和不均匀沉降,同时解决桩的负摩阻力问题,采用注浆加固工艺对填土进行加固,并通过在坑内、坑外进行预应力管桩试桩验证加固效果。结果表明,填土经注浆加固后的性质明显提高,采用注浆技术进行加固处理是合理的。     

考虑剪力环、泥皮和防腐涂层作用的钢管复合桩工作性能模型试验研究

依托港珠澳大桥建设,通过5组不同组合的钢管复合桩模型试验,其中2组试件设有剪力环,开展了内置剪力环、泥皮和防腐涂层对钢管复合桩工作性能影响的研究,比较和分析试件的荷载-变形曲线、截面变形规律、钢管与剪力环变形等。试验结果表明,剪力环、泥皮和防腐涂层对钢管复合桩的工作性能具有一定的影响;泥皮和防腐涂层使钢管复合桩的黏结强度降低,而剪力环加强了钢管与核心混凝土的联结,钢管的受力及变形显著增加。在泥皮、防腐涂层和剪力环共同作用下,桩截面变形呈"倒v"或"m"型,不再满足经典力学的平截面变形假定。在泥皮、防腐涂层和剪力环间距S≤2D(D为桩径)的条件下,剪力环的嵌固作用可以完全克服泥皮和防腐涂层的不利影响。在试验结果研究的基础上,进一步探讨泥皮、防腐涂层和剪力环不同组合下钢管复合桩的刚度计算问题,并给出了在弹性阶段范围内钢管复合桩刚度计算公式,泥皮(厚度0.1 mm)和防腐涂层使其刚度降低,剪力环则使其增加。其研究结果可为钢管复合桩基工程设计提供重要的参考。     

施工期某工业厂房及地面的变形特征分析

某工业厂房位于沿海软土地区,施工期间发生大面积开裂和地面沉降。研究其变形破坏特征,分析桩基施工前后大面积地面回填对工程产生的严重影响,分析地基变形的深层原因,解释在无上部荷载情况下基础梁断裂的原因。此研究对今后类似工程建设具有参考和警示作用。     

复杂背景下提高精度的眼睛定位方法

提出了一种在基于肤色的人脸检测中通过进行相似度计算来实现人眼特征提取和定位的算法.其目的是在较复杂的背景环境下对静态图片中的人脸进行检测,找出脸部区域并对该人脸进行眼睛定位.先进行肤色分割来完成人脸的区域检测,然后在检测出的人脸范围中利用人脸的几何特征进行快速的眼睛定位.在人脸区域检测过程中使用均值滤波提高人脸区域定位的准确度.实验结果证明,这种方法是准确的、可靠的和快速的.     

Radial groundwater flow to a finite diameter well in a leaky confined aquifer with a finite‐thickness skin

A mathematical model that describes the drawdown due to constant pumpage from a finite radius well in a two‐zone leaky confined aquifer system is presented. The aquifer system is overlain by an aquitard and underlain by an impermeable formation. A skin zone of constant thickness exists around the wellbore. A general solution to a two‐zone leaky confined aquifer system in Laplace domain is developed and inverted numerically to the time‐domain solution using the modified Crump (1976) algorithm. The results show that the drawdown distribution is significantly influenced by the properties and thickness of the skin zone and aquitard. The sensitivity analyses of parameters of the aquifer and aquitard are performed to illustrate their effects on drawdowns in a two‐zone leaky confined aquifer system. For the negative‐skin case, the drawdown is very sensitive to the relative change in the formation transmissivity. For the positive‐skin case, the drawdown is also sensitive to the relative changes in the skin thickness, and both the skin and formation transmissivities over the entire pumping period and the well radius and formation storage coefficient at early pumping time. Copyright © 2009 John Wiley & Sons, Ltd.