The fisherly imagination: The promise of geographical approaches to marine management

The management of the sea has increased exponentially in the last half-century, and different academic disciplines have been vital in shaping this management. Human geography, despite its explicit focus on the human–environment nexus, has so far had little impact on human relations with the sea. Based on empirical research conducted in England and Scotland, we argue that human geography is uniquely placed to offer effective solutions to marine resource management problems, and that geographers have the potential to offer key insights into how human populations can best interact with the living seas. Three of the most important current scholarly ‘imaginations’ of the sea, and the policies they inform (economics and market-based management, conservation biology and area based protection, and anthropology and community management), are outlined. A potential ‘geographical imagination’ of the sea, drawing on key themes in contemporary scholarship is then presented, and grounded in empirical research. It is argued that human–ocean relations should be a key feature of geographical research agendas.     

天文学英语新词自动提取系统

科技名词中文译名标准化和规范化工作是推动我国科技进步和科学知识传播的重要基础。新的科学概念和技术名词层出不穷,如何及时发现并确定新生术语的中文译名是一项普遍的社会需求。介绍了一套全新的天文学英语新词自动提取系统。该系统综合使用脚本过滤、术语识别、正则表达匹配等多种方法,能够自动追踪Ar Xiv论文数据库的更新,分析天文学论文的内容,生成推荐术语列表,从而将学科专家从繁重的科技新词收集整理工作中解放出来,把有限的精力集中到更能体现专业素养的新词审定工作当中。这个系统将为推动天文学等基础学科的新词收集,乃至学科标准化等工作发挥积极作用。     

The Petrology and Mineralogy Analysis of Noble Metal Alloys in the Inclusions of a Chondrite: An Implication on the Evolution of the Solar Nebula

The calcium-aluminium-rich inclusions (CAIs) in chondrites are believed to be the most early solids formed in the solar system, and retain the original information of the early solar nebula. However, in-depth researches revealed that most inclusions had experienced a complex history of evolution, including partial melting and secondary alteration. Focused on the refractory and chemically stable noble metal particles in the CAI of a CV meteorite (NWA 2140), a study of astrochemistry is made in this paper. The petrology and mineralogy analysis as well as the composition determination have been made on the noble metal particles. Based on the result of composition analysis, the thermodynamic process experienced by the CAI is inferred, and two kinds of noble metal alloys are identified, which correspond to the early-stage condensation products and the secondary alteration products of primordial metals, respectively.     

太阳中微子问题

文中从中微子物理学、太阳中微子的探测、标准太阳模型的建立等方面对太阳中微子问题的提出进行了回顾。各为太阳中微子探测器测量结果不同程度的偏低，以及不同类探测器测量结果之间的矛盾，使得人们对太阳中微子的研究表现出浓厚的兴趣。对太阳中微子问题可从粒子物理和天体物理两个方面进行研究。文中分别对这两个研究领域中提取的企图解决太阳中微子问题的模型作了简要评述。     

Magnetic draping of merging cores and radio bubbles in clusters of galaxies

Sharp fronts observed by the Chandra satellite between dense cool cluster cores moving with near-sonic velocity through the hotter intergalactic gas, require strong suppression of thermal conductivity across the boundary. This may be due to magnetic fields tangential to the contact surface separating the two plasma components. We point out that a super-Alfvenic motion of a plasma cloud (a core of a merging galaxy) through a weakly magnetized intercluster medium leads to 'magnetic draping', formation of a thin, strongly magnetized boundary layer with a tangential magnetic field. For supersonic cloud motion,   M _s≥ 1  , magnetic field inside the layer reaches near-equipartition values with thermal pressure. Typical thickness of the layer is  ∼ L / M ²_A≪ L   , where L is the size of the obstacle (plasma cloud) moving with Alfvén Mach number   M _A≫ 1  . To a various degree, magnetic draping occurs for both subsonic and supersonic flows, random and ordered magnetic fields and it does not require plasma compressibility. The strongly magnetized layer will thermally isolate the two media and may contribute to the Kelvin–Helmholtz stability of the interface. Similar effects occur for radio bubbles, quasi-spherical expanding cavities blown up by active galactic nucleus jets; in this case, the thickness of the external magnetized layer is smaller,  ∼ L / M ³_A≪ L   .     

A non‐coaxial critical state soil model and its application to simple shear simulations

The yield vertex non‐coaxial theory is implemented into a critical state soil model, CASM (Int. J. Numer. Anal. Meth. Geomech. 1998; 22 :621–653) to investigate the non‐coaxial influences on the stress–strain simulations of real soil behaviour in the presence of principal stress rotations. The CASM is a unified clay and sand model, developed based on the soil critical state concept and the state parameter concept. Without loss of simplicity, it is capable of simulating the behaviour of sands and clays within a wide range of densities. The non‐coaxial CASM is employed to simulate the simple shear responses of Erksak sand and Weald clay under different densities and initial stress states. Dependence of the soil behaviour on the Lode angle and different plastic flow rules in the deviatoric plane are also considered in the study of non‐coaxial influences. All the predictions indicate that the use of the non‐coaxial model makes the orientations of the principal stress and the principal strain rate different during the early stage of shearing, and they approach the same ultimate values with an increase in loading. These ultimate orientations are dependent on the density of soils, and independent of their initial stress states. The use of the non‐coaxial model also softens the shear stress evolutions, compared with the coaxial model. It is also found that the ultimate shear strengths by using the coaxial and non‐coaxial models are dependent on the plastic flow rules in the deviatoric plane. Copyright © 2006 John Wiley & Sons, Ltd.     

依巴谷星(104297)相对于伽里略卫星Callisto的CCD位置测量

１９９７年１１月１４日晚，在中国科学院云南天文台１米望远镜上用新安装的１０２４２ＣＣＤ观测到了木星的两颗伽里略卫星；Ｅｕｒｏｐａ和Ｃａｌｌｉｓｔｏ及一颗依巴谷星（星号为 １０４２９７）．当采用新的 ＪＰＬ ＤＥ４０５和 Ｓａｍｐｓｏｎ－Ｌｉｅｓｋｅ理论（Ｇ５）计算卫星的理论位置并相对于Ｃａｌｌｉｓｔｏ测量恒星位置时，视位置的观测值与计算值之差的平均值在赤经和赤纬方向分别为△α＝－０″０２９±０．″０１２，△δ＝０．″００５± ０．″０１１．这对应于平均观测历元（ＵＴ）：１９９７年１１月１４日１３时４３分５０秒．这一试验结果与 Ｃａｓａｓ等在同一时期内ＣＣＤ观测的结果有着很好的一致性 它反映了依巴谷星表体现的光学参考系与ＤＥ４０５体现的动力学参考系在观测历元具有较好的一致性．单次位置测定的标准误差在赤经赤纬方向分别为±０．″０５２和０．″０４７．这一精度明显优于 Ｃａｓａｓ等人发表的 Ｃａｌｌｉｓｔｏ的处理精度，并与目前国际上最好的伽里略卫星观测精度相当     

On the equation of state for the Λ field

The recently detected accelerated expansion of the Universe is related to the existence of a new type of matter called the Λ field or quintessence. Constraints were obtained on its equation of state from the absence of clustering of this matter on scales much smaller than the cosmological horizon. The question of how these constraints affect the possibility of fitting the accelerated expansion by such cosmological models as the Chaplygin gas model is discussed.     

Statistical significance of modal parameters of bridge systems identified from strong motion data

Modal parameters of structural systems have commonly been determined using system identification (SI) methods for damage detection and health monitoring. For determining the deterioration of the integrity of structural systems correctly, modal parameters of a healthy structure have to be obtained with adequate certainty so that these parameters can be used as reliable references for the healthy system to compare with those of the damaged system. In this study, the statistical significance of modal parameters identified using strong motion time histories recorded on two bridge structures is assessed. The confidence intervals of identified modal frequencies and damping ratios are obtained using Monte Carlo simulations and sensitivity analyses in conjunction with eigenrealization algorithm. The dependence of the statistical bounds on model parameters is examined. The effect of using different number of sensors on the statistical significance is evaluated using simulated time history data from a validated finite element model of a bridge. Copyright © 2005 John Wiley & Sons, Ltd.     

Astrophysical Implications of the Recent Shocked Deuterium Experiments

In the last few years, deuterium has been the focus of a high level of laboratory activity that was sparked by a disagreement on the experimental value of the maximum compression along the Hugoniot. Astrophysically, the uncertainty in the EOS of hydrogen is most consequential in models of the interiors of Jupiter and Saturn since a significant fraction of their mass falls in the region where the EOS uncertainty is largest. We present a study of the range of interior structures allowed by the shock-compression experiments on deuterium and constrained by astrophysical observations of the two planets. We find that the EOS uncertainty must be reduced to less than 3% along the planet’s isentrope to get good interior models of Jupiter. These models provide values for the mass of a core of heavy elements (other than H and He) and the total mass of heavy elements in these planets. The amount and distribution of heavy elements are quite sensitive to the EOS of hydrogen and constitute important clues to their formation process.