基于线性光谱混合模型的城市下垫面分类影响因素分析

基于Hyperion高光谱与ALOS全色波段的融合图像,运用线性波谱分离模型,对影响城市下垫面分类的因子进行定量分析。结果显示:随着空间分辨率的递增,融合图像光谱保真性呈下降之势,并呈现出阈值现象,但所有相关系数值都大于0.90,表明以融合图像进行线性波谱分离提取城市下垫面具有可靠性;下垫面分类总精度则整体明显下降,Kappa系数值也几乎单调减少。大气校正后下垫面分类的总精度和Kappa系数都明显高于大气校正前;当丰度分割值由10%增至60%时,生成的下垫面分类图像的精度单调降低,表明应慎用50%阈值分割法。     

An opportunity to connect the morphodynamics of alternate bars with their sedimentary products

Field investigations that help clarify local sedimentary processes involved in the migration of alternate bars as a consequence of flood events are lacking. A simple approach combining scour chains, stratigraphy and frequent bathymetric surveys is proposed to connect the dynamics of free migrating alternate bars present in disconnected channels of large sandy‐gravelly rivers with their sedimentary products and vice versa. The results show that the spatial distribution of bars before a flood partly governs the scour and fill processes and that the sediment transport rates vary significantly on a single cross‐section. This can be due to preferential axes of the migration of the bars determined by their location on the cross‐section, the bank direction and the discharge. The approach allows the reconstruction of local sedimentary processes involved in alternate bar migration by combining maximum scour depths reached during a flood with frequent channel bed topography surveys and post‐flood stratigraphy. It is also possible to distinguish deposited and preserved sediments compared with sediments by‐passed during the flood. Copyright © 2011 John Wiley & Sons, Ltd.     

一种带构造柱混凝土砌块墙体抗震性能试验研究

提出了一种带构造柱混凝土砌块承重墙体,并已获得国家发明专利。进行了2个带构造柱混凝土砌块墙体和2个普通带芯柱混凝土砌块墙体低周反复荷载下抗震性能比较试验研究。砌块墙体高宽比为0.6和1.0,厚度均为240 mm,轴压比均为0.3。对比分析了各墙体的承载力、刚度及其退化过程、延性、耗能和破坏特征。研究表明,所提出的带构造柱混凝土砌块墙体与普通带芯柱混凝土砌块墙体相比,抗震性能显著提高。     

Numerical study of a round buoyant jet under the effect of JONSWAP random waves

This paper presents a numerical study on the hydrodynamic behaviours of a round buoyant jet under the effect of JONSWAP random waves. A three-dimensional large eddy simulation (LES) model is developed to simulate the buoyant jet in a stagnant ambient and JONSWAP random waves. By comparison of velocity and concentration fields, it is found that the buoyant jet exhibits faster decay of centerline velocity, wider lateral spreading and larger initial dilution under the wave effect, indicating that wave dynamics improves the jet entrainment and mixing in the near field, and subsequently mitigate the jet impacts in the far field. The effect of buoyancy force on the jet behaviours in the random waves is also numerically investigated. The results show that the wave effect on the jet entrainment and mixing is considerably weakened under the existence of buoyancy force, resulting in a slower decay rate of centerline velocity and a narrower jet width for the jet with initial buoyancy.     

Expressed sequence tag analysis and cloning of trehalose-6-phosphate synthase gene from marine alga Laminaria japonica (Phaeophyta)

A high quality cDNA library was constructed from the brown alga Laminaria japonica,with the titer of 1.2×10 5 pfu/ml.The average insert size of the cDNA library is about 1.6 kb.From the cDNA library,591 cDNA clones were randomly selected and sequenced.As a result,574 EST(expressed sequence tag) sequences were generated.All of the 574 ESTs were submitted to the dbEST database section of GenBank with the accession numbers from CX942625 to CX943198.The cDNA library was screened with a α-32 p labeled 453 bp T P S gene probe,which is a partial sequence yielded from Porphyra yezoensis.Four positive cDNA clones were screened and the sequencing data showed that these four cDNA clones covered majority of L.japonica TPS cDNA sequence.After PCR amplification,sequencing and assembling,the entire ORF(open reading frame) sequence of the T P S gene was obtained,which was named LjTPS.LjTPS encodes a protein containing 908 amino acids with a calculated molecular mass of 101 674 Daltons.The LjTPS gene was successfully expressed in E.coli and rice.The LjTPS gene has potential application both in plant breeding to stress tolerance and in deciphering the T P S gene function and mechanism to stress tolerance.     

The effectiveness of the ISM Code: A qualitative enquiry

Studies conducted to determine the efficacy of the ISM Code in the past include investigations of the trends of accident numbers and insurance claims and users' perceptions. None of these, however, could produce a definitive conclusion. This is because both the use of safety outcome as well as the use of perception have inherent problems and are not reliable. This paper takes a different approach. It draws on wider research on management of workplace health and safety to ascertain whether or not employment and social conditions that support effective implementation of self-regulation are present in the maritime context. The findings reveal a considerable disparity between managers' and seafarers' understanding of the use of the Code resulting in a wide gap between its intended purpose and practice. The analysis shows that the critical factor is the lack of seafarers' participation in management of workplace health and safety. The underlying causal factors for such lack of participation were located in seafarers' poor employment condition and low-trust relationship with their managers.     

厦门高集海堤开口改造工程潮流泥沙物理模型试验研究

通过潮汐水流和悬沙淤积物理模型试验,研究厦门高集海堤开口改造工程潮流泥沙问题,研究表明,高集海堤开口后,东、西海域两股水流的汇流区和分流区在高集海堤附近,东海域涨潮流速有所增大,落潮流速有所减小,西海域则相反;随着开口宽度增大,流速变幅增大,开口大于800 m后流速变幅趋缓;海堤开口后净输水方向为自东海域向西海域,有利于厦门湾内水体与外海的交换;高集海堤开口对东渡港区泥沙淤积影响不大.综合分析认为高集海堤开口宽度800～1 000 m较为合适,开口800 m时大潮条件下1d的净输水量约0.91×108m3,东渡北港区港池年平均回淤强度增大0.18 m/a左右,航道淤强增大0.05 m/a左右.     

西方经济地理学关系范式与演化范式比较研究

伴随着国际经济组织形式的多样化和社会科学理论的多元化,近20 多年来西方经济地理学出现了多种理论转向,为解释新的经济活动空间现象提供了多维视角.其中,关系转向和演化转向的研究近来显得格外活跃,都试图建立自己的理论框架,并形成了关系经济地理学和演化经济地理学两种理论范式.两种范式在一些理论假设上有很多相似之处,但对二者的比较研究却十分少见.为了更加透彻地了解两种范式的理论内涵,在对两种理论范式的产生背景、主要观点和核心概念介绍的基础上,从理论假设、核心问题、核心概念和理论构建等方面对两种范式进行了对比,进而分析了西方经济地理的走向及对中国经济地理发展的启示.     

河北省数字电磁扰动应用研究

通过数字与模拟观测对比分析,说明数模观测的一致性,结合近几年河北省及邻区中强地震,进行震例分析和研究.应用结果表明：数字与模拟观测变化一致性较好;震前数字电磁扰动出现异常变化,异常形态为：原始采集波形出现扰动变化、日均值或日总量出现高值突跳、日总量背景值上升等.     

考虑非饱和特性的黄土湿陷性与微观结构分析

利用扫描电子显微镜测试技术对3个场地16个土样的微观结构进行观测,并使用图像处理软件对微观图像进行处理、对土样孔隙的几何特征参数和分维数进行了提取,土样孔隙分布分维数为1.816~1.936。利用分形几何学原理建立非饱和土的孔隙分布函数,对天然湿度下黄土中水分分布进行分析,运用回归分析的方法对孔隙的分维数、非饱和孔隙孔隙率和湿陷性的关系进行了分析。结果表明：孔隙分维数越大,孔隙结构越复杂;天然湿度下处于非饱和状态的黄土孔隙孔径均大于40μm,黄土的湿陷系数随着孔隙分维数、非饱和孔隙孔隙率的增大而增大,非饱和孔隙是造成黄土湿陷的主要原因。