The Importance of Computational Grids in Hydraulic Numerical Models

The importance of computational grids in hydraulic numerical models is studied by numericalsimulation of jet flow in a rectangular duct which is linked with a fixed width inlet and a different widthoutlet using a standard k-ε turbulence model.The computational results show the numerical solutionsmay not be reasonable because of the incorrect computational grid and each numerical model has a grid-in-dependent solution.The computational grid has a definitive effect on the accuracy and stability of thecomputational solution,which must be divided well according to the simulated geometry and physicalcharacters of hydraulic problems.The main guidelines about the formation of computational grid in suchaspects as node distribution,smoothness and skewness of grid,have been given.     

《地质论评》、《地质学报》(中、英文版)征稿简则(要点)

正《地质论评》、《地质学报》是中国地质学会主办的地质科学学术刊物。《地质论评》主要登载各种探讨、争鸣、评述类论文和新技术、新方法论文。《地质学报》反映地质科学各分支学科及边缘学科中最新、最高水平的基础理论研究和基本地质问题研究成果。《地质学报》(中文版)和《地质学报》(英文版)分别独立刊载论文。三刊均为大16开(210 mm×297 mm)。现《地质论评》和《地质学报(英文版)》为双月刊,《地质学报》(中文版)为月刊。《地质论评》2016年     

Spatial-temporal characteristics of epidemic spread in-out flow——Using SARS epidemic in Beijing as a case study

For better detecting the spatial-temporal change mode of individual susceptible-infected-symptomatic-treated-recovered epidemic progress and the characteristics of information/material flow in the epidemic spread network between regions,the epidemic spread mechanism of virus input and output was explored based on individuals and spatial regions.Three typical spatial information parameters including working unit/address,onset location and reporting unit were selected and SARS epidemic spread in-out flow in Beijing was defined based on the SARS epidemiological investigation data in China from 2002 to 2003 while its epidemiological characteristics were discussed.Furthermore,by the methods of spatial-temporal statistical analysis and network characteristic analysis,spatial-temporal high-risk hotspots and network structure characteristics of Beijing outer in-out flow were explored,and spatial autocorrelation/heterogeneity,spatial-temporal evolutive rules and structure characteristics of the spread network of Beijing inner in-out flow were comprehensively analyzed.The results show that(1)The outer input flow of SARS epidemic in Beijing concentrated on Shanxi and Guangdong provinces,but the outer output flow was disperse and mainly includes several north provinces such as Guangdong and Shandong.And the control measurement should focus on the early and interim progress of SARS breakout.(2)The inner output cases had significant positive autocorrelative characteristics in the whole studied region,and the high-risk population was young and middle-aged people with ages from 20 to 60 and occupations of medicine and civilian labourer.(3)The downtown districts were main high-risk hotspots of SARS epidemic in Beijing,the northwest suburban districts/counties were secondary high-risk hotspots,and northeast suburban areas were relatively safe.(4)The district/county nodes in inner spread network showed small-world characteristics and information/material flow had notable heterogeneity.The suburban Tongzhou and Changping districts were the underlying high-risk regions,and several suburban districts such as Shunyi and Huairou were the relatively low-risk safe regions as they carried out minority information/material flow.The exploration and analysis based on epidemic spread in-out flow help better detect and discover the potential spatial-temporal evolutive rules and characteristics of SARS epidemic,and provide a more effective theoretical basis for emergency/control measurements and decision-making.     

Experimental Researches on Reflective and Transmitting Performances of Quarter Circular Breakwater Under Regular and Irregular Waves

A series of regular and irregular wave experiments are conducted to study the reflective and transmitting performances of quarter circular breakwater (QCB) in comparison with those of semi-circular breakwater (SCB). Based on regular wave tests, the reflection and transmission characteristics of QCB are analyzed and a few influencing factors are investigated. Then, the wave energy dissipation as wave passing over the breakwater is discussed based on the hydraulic coefficients of QCB and SCB. In irregular wav...     

The progress in the study of Arctic pack ice ecology

The sea ice community plays an important role in the Arctic marine ecosystem. Because of the predicted environmental changes in the Arctic environment and specifically related to sea ice, the Arctic pack ice biota has received more attention in recent years using modem ice-breaking research vessels. Studies show that the Arctic pack ice contains a diverse biota and besides ice algae, the bacterial and protozoan biomasses can be high. Surprisingly high primary production values were observed in the pack ice of the central Arctic Ocean. Occasionally biomass maximum were discovered in the interior of the ice floes, a habitat that had been ignored in most Arctic studies. Many scientific questions, which deserve special attention, remained unsolved due to logistic limitations and the sea ice characteristics. Little is know about the pack ice community in the central Arctic Ocean. Almost no data exists from the pack ice zone for the winter season. Concerning the abundance of bacteria and protozoa, more studies are needed to understand the microbial network within the ice and its role in material and energy flows. The response of the sea ice biota to global change will impact the entire Arctic marine ecosystem and a long-term monitoring program is needed. The techniques, that are applied to study the sea ice biota and the sea ice ecology, should be improved.     

应力松弛作用对未固结砂岩等效弹性性质的影响

未固结碎屑砂岩储层是国内外重要的油气储层类型之一,其物理本质是由离散颗粒组成的软凝聚态物质.在地震勘探中通常使用Hertz-Mindlin等效介质模型来计算未固结砂岩的地震弹性特征,但该模型在使用中通常会得到明显偏高的剪切模量值.基于3D离散元技术,对颗粒介质在单轴压缩与纯剪两种过程中的力学响应进行离散元数值模拟,从微...     

海上地震勘探GI枪子波数值模拟

GI枪震源已经逐步成为海上地震勘探的主要激发方式。常规气枪只有一个腔室,而GI枪具有G腔和I腔2个腔室,能够较好地压制气泡振荡。基于自由气泡振动理论,分析GI枪的激发机制,在考虑气泡壁的热传导作用和流体粘度对气泡振动影响的基础上,建立了海上勘探GI枪子波数值模型,并对气泡的振动过程和远场地震子波进行了数值模拟。结果表明:当G腔内气体释放所形成的气泡体积达到最大时,I腔内气体的释放有效地抑制了气泡的收缩,气泡壁运动速度明显减小,气泡变得稳定;GI枪激发所产生的子波具有明显的峰值和较小的旁瓣,有利于高分辨率海上地震勘探。     

辽宁北票四合屯地区早白垩世早期鸟类集群死亡原因探析

通过大规模系统挖掘,在对四合屯7个含鸟层进行澄清的基础上,以四合屯剖面为主,黄半吉沟剖面为辅,分别在含鸟层的底板、含鸟层、含鸟层顶板,不含鸟沉积层及含鸟层底部的火山岩系统取样,进行多项相关元素分析。应用元素地球化学理论,根据其环境地球化学场特征,结合相关地质资料,重点对鸟类集群死亡原因进行了探讨。结果表明包括二氧化硫(SO2)、硫化氢(H2S)、铅(Pb)的卤化物盐(PbBr2、PbBrCl、Pb(OH)Br、(PbO)2PbBr2)及汞(Hg)蒸汽等有毒气体是导致鸟类集群死亡的主要原因;含鸟化石密集的原因是由于火山口在四合屯附近。     

SHRIMP Age of Exotic Zircons in the Mengyin Kimberlite, Shandong, and Their Formation

1Introduction Due to its special properties and ubiquitous occurrence,zircon can be found in the crust,mantle,lunar rocks,meteorites,etc.And it is the ideal mineral to test the formation age of rocks(Xie et al.,2001).However,zircons are an exceptionally rare component of kimberlites.They have various sources and courses of formation.Zircons crystallized from kimberlitic magma are usually have large sizes and a maximum diameter of20mm was reported.Typically,they have low contents of U and Th,…     

《地质论评》新增栏目启事

正第40届编委会第一次会议讨论决定,《地质论评》自2019年起,在原有"问题讨论"、"科技述评"、"研究进展"、"通讯资料"、"消息报道"和"新书介绍"6个专栏的基础上,新增两个栏目:"专题细解"和"窥斑速报"。"专题细解"(Theme Paper)专栏为一组对同一专题进行研究的文章,一般由4～7篇组成,一般应当包括一篇评述,其余为专题研究或讨论。"窥斑速报"(Express Letter)专栏快速发表对重要地质问题有关证据或重要地质体的新发现,该栏文章的格式与正