A CIP-based numerical simulation of free surface flow related to freak waves

An enhanced numerical model for simulating two-dimensional incompressible viscous flow with distorted free surface is reported. The numerical simulation is carried out through the CIP （Constrained Interpolation Profile）-based method, which is described in the paper. A more accurate interface capturing scheme, the VOF/WLIC scheme （VOF：Volume-of-Fluid;WLIC：weighed line interface calculation）, is adopted as the interface capturing method. To assess the developed algorithm and its versatility, a selection of test problems are examined, i.e. the square wave propagation, the Zalesak’s rigid body rotation, dam breaking problem with and without obstacles, wave sloshing in an excited wave tank and interaction between extreme waves and a floating body. Excellent agreements are obtained when numerical results are compared with available analytical, experimental, and other numerical results. These examples demonstrate that the use of the VOF/WLIC scheme in the free surface capturing makes better results and also the proposed CIP-based model is capable of predicting the freak wave-related phenomena.     

东北地区古生代地层间断

东北地区古生代在南部有一个地层间断面,北部有三个地层间断面：奥陶纪、晚志留世末-早泥盆世和早石炭世晚期-晚石炭世,相应于古亚洲洋构造域发展的不同阶段,结束于早三叠世末.最后的间断面以后,东北南部和北部古生代地层进入同步发展.     

Prediction of streamwise flow-induced vibration of a circular cylinder in the first instability range

The streamwise flow-induced vibration of a circular cylinder with symmetric vortex shedding in the first instability range is investigated, and a wake oscillator model for the dynamic response prediction is proposed. An approach is applied to calibrate the empirical parameters in the present model; the numerical and experimental results are compared to validate the proposed model. It can be found that the present prediction model is accurate and sufficiently simple to be easily applied in practice.     

NP6-1井PDC钻头断落处理与认识

随着PDC钻头的广泛使用,因PDC钻头选型与钻遇地层的不匹配,或PDC钻头本身质量问题,也遇到一些井下复杂情况。此文介绍NP6-1井在311．2mm井段使用PDC钻头钻至井深2878．76m时,PDC钻头从公扣根部折断留在井底,加工公锥和采取适当措施成功地打捞出落鱼,避免侧钻,挽回了经济损失。该井成功打捞出PDC钻头,为同类型的井下落鱼或小落鱼提供参考与借鉴。     

超大型沉井首次接高受力及变形规律初探

依托马鞍山长江大桥南锚碇沉井的首次接高,对其竖向沉降、隔墙墙底土压力和隔墙底板受力情况进行了监测。结果表明,超大型沉井兼有条形基础的特点和整体工作性能,能够承受较大的竖向变形,与单纯考虑地基承载力相比,更适合于按变形控制接高。沉井接高时普通隔墙下的土压力小于分区隔墙,并且普通隔墙下部土体会先达极限承载力,后续接高产生的荷载转而由分区隔墙（或井壁）来承担。沉井首节混凝土浇筑就已决定了隔墙底板的应力大小和分布情况,后续接高不会再引起大的改变;隔墙底板中间部分受力较小,外围拉应力较大,通过井壁外土体的密实回填可有效降低此部分拉应力。     

基于“要素对象空间信息指纹”的变化空间数据同步技术的研究

随着空间数据库的建设和应用的发展,空间数据动态更新和数据分发成为确保数据现势性的主要研究课题,系统提出将地形地物要素数据的坐标数组通过MD5算法生成32位字符串的"要素对象空间信息指纹"作为判定要素数据变化的方法,结合Oracle数据库CDC技术,快速获取空间变化数据,再通过ETL数据同步机制流程化管理空间同步过程,多节点、多级联按需配置同步图层,实现不同Oracle数据库版本、不同Arc SDE版本间的空间数据断点续传同步功能。     

近40 年山西省初终霜日的变化特征

利用山西省境内分布较为均匀的52 个地面气象站1970-2009 年的霜日观测资料,采用线性倾向估计法、累积滤波器法结合非参数统计检验方法分析了初终霜日的基本特征及其变化趋势;利用M-K法分析了霜日的突变特征。结果表明：初霜日、终霜日的出现以及无霜期的长短与地理因素密切相关,随着纬度逐渐偏北、海拔逐渐升高,初霜日提前、终霜日推后、无霜期缩短。从全省平均情况看,初霜日呈现显著的推后趋势,无霜期呈现显著的延长趋势,而终霜日的变化则以波动为主,线性变化趋势不显著。从突变检测情况看,初霜日、终霜日和无霜期在40 年间均存在一次明显突变,初霜日的突变点出现在2000 年,终霜日和无霜期的突变点出现在1997 年。从变化趋势的空间分布看,初霜日显著推后的区域大片集中在晋中东部、吕梁北部和忻州西部,以及分散在运城南部、临汾西北部和大同南部。终霜日显著提前的区域位于晋中东部山区、吕梁山东部和忻州西部。无霜期显著延长的区域位于西北部黄河沿岸、省境中东部和运城南段。变化趋势为初霜日提前、终霜日推后和无霜期缩短的区域未通过显著性检验。     

青藏高原冰湖研究进展及趋势

冰湖是由于冰川活动或者退缩产生的融水在冰川前部或者侧部汇集而成的,可分为冰川终碛湖(冰碛阻塞湖)、冰川阻塞湖、冰斗湖和冰蚀槽谷湖。其中分布数量较多、规模较大,且灾害风险较高的是冰川终碛湖。因此,冰川终碛湖是研究冰湖的主要对象。受全球气候变暖的影响,冰湖溃决产生的洪水、泥石流等重大冰川灾害的发生频率有所升高,灾害的影响程度以及范围也有所加大,引起了冰川山地国家的广泛关注。青藏高原内部发育着36793条现代冰川,冰川面积49873.44km2,分别占中国冰川总条数、总面积和冰储量的79.5%、84%和81.6%。在全球气候变暖的大背景下,多数冰川呈加速消融及退缩的态势,导致了冰湖溃决洪水和冰川泥石流等重大冰川灾害发生频率的加剧和影响程度的加大。本文围绕冰湖溃决条件、冰湖稳定性评价、冰湖溃决洪水模拟等几个研究方面,对青藏高原冰湖研究的现状及进展进行了较为系统的总结,并对未来研究趋势进行了展望。     

The Geographical Distribution of Mental Disorder in Denmark 1971–1990: A Study of First Admission Rates

Geografisk Tidsskrift, Danish Journal of Geography 97: 132–142, 1997.

In the period 1971–90 the first admission rate to Danish psychiatric hospitals and wards decreased by approximately 45%. This might reflect the similar decrease in number of available psychiatric beds. Generally, the decrease of first admission rates was larger in the metropolitan area than in the rest of the country. Consequently, the disparity in admission rates between town and country was reduced. Number of available beds has gained increasing importance as a predictor of variations between counties and municipalities whereas the importance of distance to hospital and degree of urbanization has declined. As regards socio-demographic variables special importance should be attached to variables for social aid and the employment rate in the social and health sector. However, it is generally difficult to determine whether regional variations are due to differences in treatment facilities or morbidity differences. From a disaggregate analysis it will appear that the diagnoses schizophrenia and alcoholism are especially related to low status areas whereas a connection with social status regarding neuroses and manic-depressive psychoses is less obvious.     

一等水准点之记标准化与规范化研究

为保证一等水准点之记精度与质量,提高测绘人员野外工作效率,对目前的一等水准点之记进行了探讨与分析,指出了其详细位置图与点位,详细说明表达、标石断面图绘制和经纬度书写及交通路线描述中存在的缺点,并基于此提出了若干改进意见,这在一定程度上促进了一等水准点之记信息的标准化与规范化。