常用粮仓地坪沉降观测方法及精度分析

中央直属储备粮库是国家重要的基础设施,为确保新建粮库储粮安全,必须进行粮库新仓初始装粮压仓试验,利用仓内地坪沉降观测数据对云梯升降法、悬尺法、倒尺法的精度进行分析,得出倒尺法是仓内地坪沉降观测的最佳方法。     

An Overview of Deepwater Pipeline Laying Technology

The technology and methods involved in pipeline laying in shallow water have evolved to the level of routine and commonplace. However, regarding the unexpected deepwater complexity, the traditional pipeline laying techniques have to confront many new challenges arisen from the increase of the water depth, diameter of the pipe and the welding difficuhy, all of which should be modified and/or innovated based on the existed mature experiences. The purpose of this investigation is to outline the existing and new engineering laying techniques and the associated facilities, which can provide some significant information to the related research. In the context, the latest deepwater pipeline laying technology and pipe laying barges of the renowned companies from Switzerland, Norway, Italy etc., are introduced and the corresponding comparison and discussion are presented as well.     

基于运营环境和提升小波变换的桥梁损伤检测研究

根据损伤桥梁在车辆荷载作用下的动力响应特点,以及提升小波变换对信号突变信息的放大功能,提出了利用桥梁运营荷载作用下加速度响应提升小波变换系数的分布特性对结构损伤进行识别的方法。首先,采集桥梁在行车荷载作用下的加速度响应信号;然后,对加速度响应信号进行提升小波变换,分别利用加速度响应信号、加速度响应信号差,提升小波变换系数空间变化的峰值识别损伤位置;最后,对行车速度、损伤位置、损伤程度和测量噪声对损伤识别效果的影响进行了分析讨论。结果表明：在行车速度8m/s以下、测量噪声不高于5%情况下,利用运营荷载作用下桥梁单点动力响应信号提升小波变换,可以实现桥梁多处损伤的检测和识别。     

滇西北高原局地暴雨雷达回波特征

利用丽江CINRAD/CC雷达观测资料,并结合天气背景及当地地形,对2008年9月11日出现在华坪站的单点性暴雨天气进行详细分析发现:雷达回波强度场上,由前端积状云和后部层积云组成的混合降水回波移过测站;速度场上出现了"逆风区"的特征,并在其移动路径周围出现了强降水天气;5.2 km以上高度的垂直风廓线显示,冷平流控制时系统维持,冷平流减弱时系统减弱;500 hPa副高较强,冷空气南下回流,致使700 hPa切变线东南移,产生强降水。华坪县特殊的地形与该次暴雨的风场结构相配合形成迎风坡的动力抬升条件,是此次暴雨的又一特征。     

“探海1号”大陆架科学钻探平台液压升降系统

“探海1号”大陆架科学钻探平台是一座自升式浅海地质钻探平台,液压升降系统作为其核心部分,通过执行放桩、插桩、升（降）平台、拔桩等动作,来实现平台的升降。该系统由4套独立的液压升降装置组成,每一套液压升降装置工作时由操作台发出指令,液压驱动系统提供动力,升降桶执行动作,通过这3部分的协调配合确保执行动作的效果。本文详细阐述了平台液压升降系统的性能、结构、工作原理、操控等方面的设计,并且针对实际应用中发现的不足,提出了优化改进方向。     

超大型海洋结构物海上安全运输绑扎件设计

绑扎件的制作及安装过程中,由于考虑的因素不够周全,或强度不够造成海难事故,或因设计过于保守而造成材料的浪费。根据具体工程项目,结合实际工程经验,对该类绑扎系统设计中应注意的关键问题进行了剖析,包括构件的结构形式及尺寸设置,绑扎系统布置以及构件尺寸与运输船甲板结构的关系,绑扎系统受力计算模型的简化以及结构物对同一组绑扎件构件之间连接的模拟等,并给出具体的工程实例。可为海洋结构物运输的绑扎系统设计以及完善或制订相关标准提供依据,并有助于提高驳船结构计算机辅助设计与强度分析的精度。     

边缘保留自适应提升形态小波及其在甲藻特征提取中的应用

自适应提升形态小波将多分辨率分解和图像空域中目标的几何结构和局部特征相结合,可以满足特定图像处理任务的需要。本文针对甲藻类细胞显微图像边缘模糊、对比度低等不利于甲沟特征提取的困难,构造1种边缘保留自适应提升形态小波。该小波将图像的边缘作为重要的局部特征,更新提升根据是否是边缘像素选择保留、锐化滤波或平滑滤波,使得分解后的近似图像中,图像边缘得以保留,而灰度变化缓慢的区域得到了平滑。实验结果证明:甲藻细胞经边缘保留自适应提升形态小波分解后的近似图像,在一定程度上突出了目标边界,较之原始图像,更有利于甲沟特征的提取。     

Analysis of Meteorological and Terrain Features Leading to the Izmir Flash Flood, 3–4 November 1995

Flash floods associated with heavy precipitation has become a hazardous phenomenon along the Mediterranean coasts of Turkey in recent years. During 3 and 4 November 1995 heavy and intense rainstorm activity over the Aegean coast led to flash flooding in the city of zmir. Damage exceeded $50 million and 61 people died as a result of the flood. The Karyaka district suffered the most severe damage. This study presents an analysis of the meteorological settings that led to the development of these intense storms and describes the role of the terrain features involved in the zmir flood.The important mesoscale features which initiated the severe weather outbreak included pronounced low-level advection, positive vorticity and strong upper level divergence. A surface low centered over the Aegean Sea enhanced the advection of warm and moist unstable air masses coming from the southwest over the Mediterranean Sea along a southwesterly low level jet (LLJ). A squall line oriented NE-SW over the Aegean Sea also contributed to the storm development, and intensity of the storms was further enhanced by the orographic effect. The presence of a frontal system, the stability indices associated with the event, and other meteorological features are all reminiscent of the synoptic type flash floods identified by Maddox. While the pressure and moisture patterns were favorable for severe storm activity, nonmeteorological factors including the topography, geomporphology, and and land-use contributed to the flooding to a great extent. Settling in the flood-prone zone, insufficient floodwater structures, and the lack of channel improvements in the creeks enhanced flood damage to the city. Many of the deaths occurred in the settlements located in the flood-prone zone of the Ilca and Dallk creeks.     

Dynamic characteristics of spring sandstorms in 2000

Systematical analyses of spring sandstorms in 2000 affecting Beijing area are carried out. Results revealed the key dynamic mechanisms of dust storm during its mobilization, lifting, horizontal advection and deposition processes. It turns out that in the processes of sandstorms influencing Beijing area in March–April 2000, the dynamic conditions for dust mobilization are significantly correlated with phenomena, such as cold air-related climatic activities, clay soils area of North China and surface friction velocity anomaly. The characteristics of sandstorm can be described by composite mode of dust particles mobilization-lifting-long-range transport. This paper will provide scientific evidences for further studies, prediction and harness of sandstorms in China.     

WRF4.0模式陆气耦合对不同物理参数化方案的敏感性初探

模式的不同参数化方案会对模拟的天气和气候产生影响,但如何影响陆气耦合还不是很清楚。利用WRF 4.0模式设计了一组16种不同参数化方案组合的集合试验,对华北地区2013年夏季气候进行模拟。结果表明,不同积云对流参数化方案对模拟的降水平均态影响较大,其次是短波辐射方案,而微物理方案影响较小。进一步利用潜热通量(LH,Latent Heat flux)和土壤湿度(SM,Soil Moisture)、抬升凝结高度(LCL,Lifting Condensation Level)的相关系数R_(SM,LH)和R_(LH,LCL)表征陆气耦合过程,评估了陆气耦合对不同参数化方案的敏感性。模式模拟的R_(SM,LH)在不同区域随着平均降水、相对湿度的增加以及平均短波辐射的减少而减小,而R_(LH,LCL)的变化正好相反。它们内在的物理机制类似,与气候态的干湿变化密切相关,即随着土壤湿度趋于饱和,蒸散发过程逐渐受太阳辐射的限制,陆面对大气的影响减弱。另外,陆气耦合强度受积云对流方案、微物理方案和短波辐射方案的影响而产生差别,这与不同参数化方案模拟的气候态的不同密切相关,因此本研究对于WRF 4.0模式中参数化方案特别是积云对流方案的选择同样有着重要的指导意义。