暴雨诱发滑坡的高效无网格大变形数值模拟

渗流与土体的大变形耦合损伤破坏问题是暴雨诱发滑坡数值模拟的重要内容,目前对滑坡的全过程大变形非线性损伤破坏的仿真分析仍是一个难点。本文基于稳定节点积分再生核质点伽辽金无网格法和大变形增量型本构关系,提出了一套能模拟暴雨诱发非饱和土质边坡大变形损伤破坏的高效分析方法。该方法应用拉格朗日稳定节点积分,保证了数值积分的稳定性和高效性;同时采用非饱和土的物理力学性质来模拟降雨过程中边坡土体性质的演化,并以各项同性损伤函数和Drucker-Prager屈服准则反映土体的弹塑性损伤状态。该方法的非局部近似特性可以有效地模拟从剪切带起始到发生滑坡的整个大变形损伤破坏过程。通过典型算例验证了方法的有效性,并研究了滑坡发生时间与降雨强度和初始饱和度的关系

饱和土体中稳态渗流的高效无网格分析

利用稳定节点积分思想,构造一种求解饱和土体中稳态渗流问题的快速Galerkin无网格方法.该方法通过建立非局部光滑节点水力梯度,具有节点积分高效的特点,同时避免形函数在节点上直接求导,为稳态渗流分析提供有效的稳定保障.均匀渗流与自由面渗流算例的计算结果表明,该方法分析渗流问题高效且准确,能精确模拟任意均匀渗流场,在求解自由面迭代问题时,能避免有限元求解迭代问题时重划网格的工作,迭代收敛速度快

稳定节点积分伽辽金无网格法的应力计算方法研究

应力计算是基于稳定节点积分的伽辽金无网格法的重要组成部分.该文着重研究稳定节点积分伽辽金无网格法的应力计算方法,对稳定节点积分方法的变分一致条件进行了讨论,证明当节点代表域内的应变采用非局部光滑应变时,相应的应力在节点代表域内为常数,稳定节点积分伽辽金无网格离散方程是变分一致的.文中提出了三种节点应力计算方法,研究表明,基于位移梯度的节点应力计算方法不满足变分一致性要求,而采用光滑应变的节点应力计算方法和一致形心应力计算方法满足变分一致性要求.典型数值算例的误差分析表明,满足变分一致性不一定确保得到更为精确的结果,而基于光滑应变的一致形心应力计算方法总是较其它两种方法更为精确

Advance in the Research of Marine Algicidal Functional Bacteria and Their Algicidal Mechanism

作者简介: 李东( 1986-) ,男,福建宁德人,硕士研究生,主要从事应用与环境微生物研究.E-mail: [email protected] 通讯作者: 郑天凌( 1955-),男,福建莆田人,教授,主要从事应用与环境微生物研究.E-mail: microzh@ xmu.edu.cn[中文文摘]基于"菌—藻关系"的理念,深入探讨海洋溶藻功能细菌作为潜在的有效防治有害藻华的微生物,已成为学者们的研究热点。但大多的研究主要涉及菌株的分离、鉴定及功能活性物质的纯化,溶藻机理的研究鲜有报道。主要概述了当前国内外海洋环境中溶藻功能细菌溶藻机理的研究进展,并探讨分析了利用海洋溶藻功能细菌防治有害藻华的未来发展方向,提出了该领域今后的重点研究任务。[英文文摘]Based on the relationship between bacteria and algae， the marine algicidal bacteria as a potential microorganisms to effectively eliminate the impact of harmful algae blooms，has become the research hot topic. But most researches are mainly involves in the algicidal bacteria isolation,identification and the algicidal substances purification.However,the mechanisms of bacteria lysing algae are rarely reported.Here.the latest development of algicidal mechanisms is briefly reviewed,and the future development prospects and trends are also discussed.国家自然科学基金重点项目“我国近海海洋细菌的生态过程及关键菌群影响赤潮生消的机理”(编号:40930847);国家自然科学基金面上项目“一株海洋高效抑藻活性肽产生菌的研究”(编号:31070442);高等学校博士学科点专项科研基金优先发展领域“一株新分离的特殊、高效溶藻微生物的作用机理与生态过程研究”(编号:20120121130001)资

空间·事件·漫游

研究空间、事件和漫游的关系,旨在研究构建氛围和事件对建筑的活力的影响。本文通过梳理关于"空间与知觉"的探索脉络,追溯了屈米、库哈斯等建筑师的理论根源。从艺术家对"空间与主观感知"的探索,到建筑流派对"空间与事件之间相互依存"的声明,发展到部分"用激发事件可能性来塑造空间"的解构主义手法,这一系列探索承前启后,都是针对现代主义理性控制的反抗和回应,也是事件空间作为主观倾向设计思路开始崭露头角的一方面历程

A Study on the Effects of Topics on an Opinion Sentences Identification System for Micro-blog Data

为了从海量的网络信息中迅速准确地获取评价信息,观点句识别已经成了自然语言处理的一个研究热点。现在观点句识别系统大都是基于机器学习的方法,一般使用机器学习的方法来进行分类会受到领域差异性影响。针对这个问题,该文对微博观点句识别系统是否会受到微博话题影响做了经验性研究,同时为了弥补训练数据的不足,该文通过规则方法自动标注网络数据进行了训练集的扩充。实验结果表明,微博话题间存在差异,进行分话题模型训练可以提升微博观点句识别系统的性能。As an important stage for information extraction, the problem of Opinion Sentence Identification(OSI) has attracted more and more attentions from NLP researchers in the past decade.Similar to other areas in NLP, most current OSI systems are built based on machine learning(ML) technologies, which often suffer from the problem of domain/topic adaptation.In this paper, an empirical study was conducted to test whether the topic difference among the micro-blog data effects on the performance of an ML-based OSI system, which used rule-based automatic annotation methods to expand the training set.The experimental results indicated that by introducing a topic classifier and performing the training based on the sub topics, the performance of the OSI system for micro-blog data could be improved significantly.国家自然科学基金项目(61005052); 国家科技支撑计划课题(2012BAH14F03); 中央高校基本科研业务费专项资金(2010121068); 福建省自然科学基金项目(2011J01369

Reorder discrete cosine transform method for video compression

为了提高离散余弦变换(dCT)在视频图像编码中的效率,根据dCT对非水平/非垂直残差信号较敏感的特点,从改变残差信号分布的角度出发,提出一种重排dCT方法.对待编码的残差图像块进行像素位置重排,使得残差信号的方向与水平或垂直方向相一致;对重排后的图像块进行2维dCT,从而减少dCT系数的高频分量,提高压缩效率.实验结果表明:在不考虑重排信息的情况下,重排dCT比传统dCT性能提高0.20~0.30db;在考虑重排信息的情况下,重排dCT比传统dCT性能提高0.05~0.20db.In traditional video compression,discrete cosine transform (DCT) is sensitive to the prediction error with non-horizontal or non-vertical orientations.To improve the performance of DCT in video compression,this work proposed a reorder DCT method,from the view point of modifying signal distribution.In the algorithm,reorder operation was first used to change the pixel position of the blocks to be transformed,and then 2D-DCT was applied.Experimental results show that the reorder DCT can reduce the number of DCT coefficients at high frequency.Compared to the traditional DCT,the reorder DCT achieved 0.20-0.30 dB peak signal-to-noise ratio (PSNR) gain without reorder information.With reorder information,0.05-0.20 dB PSNR gain could be obtained.福建省科技厅重大专项资助项目(2007HZ0003

Satellite-derived surface water pCO(2) and air-sea CO2 fluxes in the northern South China Sea in summer

An empirical approach is presented for the estimation of the partial pressure of carbon dioxide (pCO(2)) and air-sea CO2 fluxes in the northern South China Sea in summer using satellite-derived sea surface temperatures (SSTs), chlorophyll-a (Chl a) concentrations, and wind fields. Two algorithms were tested. The first used an SST-dependent equation, and the other involved the introduction of Chl a. Regression equations were developed for summer based on in situ data obtained in July, 2004. Using the monthly average SST and Chl a fields derived from the advanced very high resolution radiometer (AVHRR) and the SeaWiFS (sea-viewing wide field of view sensor), respectively, the monthly pCO(2) fields were computed. The derived pCO(2) was compared with the shipboard pCO(2) observations conducted in July, 2000. This resulted in a root-mean-square error of 4.6 mu atm, suggesting that the satellite-derived pCO(2) was in general agreement with the in situ observations. The air-sea CO2 flux was further computed with the aid of the monthly mean QuikSCAT wind speed. We contend that more shipboard data are necessary for refining the empirical algorithms and reducing the uncertainty in the results. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.National Basic Research Program of China [2009CB421200, 2009CB421201]; National Natural Science Foundation of China [40521003, 90711005]; High-Tech R&D Program of China [2006AA09A302, 2007AA09Z127

溶藻细菌BS03(Microbulbifer sp.)对塔玛亚历山大藻生长及抗氧化系统的影响

【目的】研究溶藻细菌BS03(Microbulbifer sp.)胁迫下塔玛亚历山大藻细胞光合作用、抗氧化酶系统和半胱氨酸蛋白酶3(Caspase-3)变化,探讨溶藻细菌BS03对塔玛亚历山大藻的溶藻机制。【方法】通过0.5%、1.0%、1.5%、2.0%不同终浓度BS03上清液处理藻细胞后12、24、36、48h取样,测定溶藻过程藻细胞光合色素、叶绿素荧光效率、抗氧化酶系统、Caspase酶活性变化。【结果】(1)BS03上清液处理藻细胞后,藻细胞叶绿素a含量和叶绿素荧光Fv/Fm比值随BS03上清液处理时间延长和浓度的增加呈逐渐下降趋势;低浓度处理组藻细胞类胡萝卜素含量上升到一峰值,高于对照组后逐渐回落,而高浓度处理组类胡萝素含量呈下降趋势,低于对照组;(2)藻细胞抗氧化酶保护系统(SOD和CAT)活性随着BS03上清液处理浓度增加而升高,但随着处理时间的延长呈现先上升后下降趋势。藻细胞膜脂过氧化产物MDA积累量随着BS03上清液处理时间延长和处理浓度的增加而显著提高;(3)处理组藻细胞Caspase-3活性显著高于对照组,呈现出类似程序性死亡特征。【结论】BS03的抑藻机理可能是通过抑制藻细胞光合作用,降低抗氧化酶活性、加大膜脂过氧化起到对塔玛亚历山大藻的溶解作用,并呈现出类程序性死亡特征