中国近海棱梭群体形态学和耳石形态学研究

为研究棱梭不同地理群体间的形态差异,使用多元统计分析方法对采集自金门、厦门、虎门、湛江、北海和防城港6个地点邻近海域的棱梭群体样本的形态和矢耳石形态两方面进行比较研究。对棱梭样本的形态研究结合传统形态学和地标形态学开展,对矢耳石的形态研究则将传统耳石形态分析法和椭圆傅里叶分析法相结合,形态和耳石形态数据的分析结果相似。主成分分析结果表明从28个棱梭形态量度指标提取的前8个主成分累积贡献率为65. 868%,从85个耳石形态指标提取的前23个主成分的累积贡献率为79. 290%,根据临界值85. 000%可以推断这6个棱梭群体间形态和耳石形态上的差异不能够单独依靠少数指标来判断;聚类分析的结果总体显示出群体间差异与地理距离等因素相关联的分布规律;在判别分析中形态学量度指标的综合判别正确率为75. 9%,而耳石形态学指标的综合判别正确率略低,为69. 3%;对棱梭形态量度指标的单因子方差分析显示湛江棱梭群体与其他群体在形态上存在显著差异的量度指标较少。栖息地环境、饵料组成和海流等可能是导致形态学差异和耳石形态差异形成的主要因素。另一方面,理化因子的相似性和群体间的交流会减弱群体间形态和耳石形态的差异。     

Trophic ecology of small yellow croaker (Larimichthys polyactis Bleeker): stable carbon and nitrogen isotope evidence

The trophic ecology of the small yellow croaker (Larimichthys polyactis) was studied using stable isotope analyses. Samples were collected from July to September 2009 and 34 individuals from eight sites were examined for stable carbon and nitrogen isotopes. Stable carbon isotope ratios (δ13C) ranged from -20.67 to -15.43, while stable nitrogen isotope ratios (δ15N) ranged 9.18-12.23. The relationship between δ13C and δ15N suggested high resource partitioning in the sampling area. Significant differences in stable isotope values among the eight sampling sites may be linked to environmental diversities involving various physical processes (such as ocean current, wind and tide) and different carbon sources. Furthermore, the stable isotope ratios may also explain the ontogenetic variability in diet and feeding, because δ13C and δ15N varied significantly with increasing body size. The findings are consistent with other studies on diet analyses in small yellow croaker. It was also demonstrated that stable isotope analysis could be used to estimate the trophic characters of small yellow croaker in feeding patterns and migrating habits.     

海底爆破振动强度衰减规律及中华白海豚保护措施研究

为确保海底爆破施工所诱发的振动不对中华白海豚造成危害,基于量纲分析法对萨道夫斯基经验公式进行修正,建立适用于预测海底爆破质点峰值振动速度的相似准数方程。在此基础上根据现场试验数据进行非线性回归运算,得到相关参数并分析了海底爆破振动强度衰减规律。分析表明:海底爆破质点峰值振速主要由单段装药量、监测点距爆心水平距离、覆盖层厚度及海水深度等因素决定。将参数值分别代入萨氏公式及新建公式计算预测值并进行误差估计,其平均误差分别为20.3%和10.0%,新建公式提高了对质点振速预测的准确性。利用新建公式及超压内安全振速估算保护中华白海豚的安全距离并提出相应的保护措施,为同类工程施工提供理论参考依据。     

围绕南海问题的信息权力作用过程与机制研究

2010年以来,南海争端呈现扩大化和复杂化的态势,形成环南海周边国家侵占岛礁、域外国家广泛介入的局面,进而推动南海问题日益走向“国际化”。分析南海问题中的国家（地区）间合作与冲突关系,挖掘南海问题“复杂化”的深层原因,这是理解当前南海局势、避免战略误判的重要支撑。文章借助GDELT新闻媒体数据库,提取2013—2021年有关南海问题的事件数据,利用年代约束聚类方法将南海问题划分为矛盾上升期（2013—2018年）和域外介入期（2019年以后）,并利用社会网络分析方法探讨南海问题中的国家（地区）间合作与冲突关系以及背后的信息生产网络。研究发现：1）矛盾上升期,围绕南海问题的合作与冲突主体主要为环南海国家;2）域外介入期,美国、英国、澳大利亚等域外国家结盟合作并围堵中国,中国在与域内国家紧密合作的同时,却成为冲突关系网络的核心,冲突关系复杂、合作关系萎缩与当前人们对南海问题有所缓和的认知形成矛盾,反映信息权力的作用愈发深远;3）信息生产网络中,美、英、澳等国家主导信息制造和加工过程,表明南海问题成为各信息行为体博弈的角力场。     

Application of saddlepoint approximation in reliability analysis of dynamic systems

The application of the saddlepoint approximation to reliability analysis of dynamic systems is investigated. The failure event in reliability problems is formulated as the exceedance of a single performance variable over a prescribed threshold level. The saddlepoint approximation technique provides a choice to estimate the cumulative distribution function (CDF) of the performance variable. The failure probability is obtained as the value of the complement CDF at a specif ied threshold. The method requires computing the saddlepoint from a simple algebraic equation that depends on the cumulant generating function (CGF) of the performance variable. A method for calculating the saddlepoint using random samples of the performance variable is presented. The applicable region of the saddlepoint approximation is discussed in detail. A 10-story shear building model with white noise excitation illustrates the accuracy and effi ciency of the proposed methodology.     

"4D"数据在生态环境监测与评价中的应用

本文在阐述由DLG、DRG、DEM和DOM组成的4D产品的信息特征的基础上,深入分析了"4D"数据在生态环境监测与评价中的功能,包括生态环境的快速动态监测、三维生态景观的直观分析和表达、DLM与DCM相结合的生态模拟、多时空尺度的生态环境分析与评价等.并以云南省生态环境监测与评价为例,研究了其在生态环境监测与评价中的技术流程,并通过案例分析,生成了系列生态环境地图.     

K-means算法复杂度的能量分析方法

传统的算法复杂度分析方法重点对算法的内在流程进行分析,而且对于数据挖掘时具有很大不确定性,执行时间不能准确确定.用物理学原理从能量的角度对数据挖掘中的经典聚类算法K-means进行分析,并从算法的本质上推导出其复杂度下限,推导出该算法能优化到的极限值.     

The effect of a topographic high on the morphological stability of a two-inlet bay system

The cross-sectional stability of two tidal inlets connecting the same back-barrier lagoon to the ocean is investigated. The condition for equilibrium is the cross-sectional area tidal prism relationship. In an earlier study [Van de Kreeke, J., 1990. Can multiple inlets be stable? Estuarine, Coastal and Shelf Science 30: 261–273.], using the same equilibrium condition, it was concluded that where two inlets connect the same basin to the ocean ultimately one inlet will close. One of the major assumptions in that study was that the water level in the basin fluctuated uniformly. In hindsight this assumption might be too restrictive. For example, in the Wadden Sea the back barrier lagoon consists of a series of basins, rather than one single basin, separated by topographic highs. These topographic highs limit but do not exclude the exchange of water between the sub-basins. For this reason in the present study, a topographic high in the form of a weir was added, separating the back-barrier lagoon in two sub-basins. The water level in the sub-basins, rather than in the back-barrier as a whole, is assumed to fluctuate uniformly. For this schematization the hydrodynamic equations are solved using a finite difference method. The results, together with the equilibrium condition, yield the equilibrium flow curve for each of the inlets. The intersections of the two equilibrium flow curves represent combinations of cross-sectional areas for which both inlets are in equilibrium. The stability of the equilibriums was investigated using a non-linear stability analysis resulting in a flow diagram. Calculations were carried out for different inlet and weir characteristics. Sinussoidal tides were the same for both inlets. The results show that for relatively large wetted cross-sectional areas over the topographic high, approaching the situation of a single basin, there are no combinations of inlet cross-sectional areas for which both inlets are in a stable equilibrium. This supports the conclusion in the earlier study. For relatively small wetted cross-sectional areas over the topographic high there is one set of stable equilibriums. In that case the two-inlet bay system approaches that of two single-inlet bay systems.     

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文学地理学视野下香港文化认同

通过文本分析和档案分析的方法,立足文学地理学分析框架和研究范式,分析了香港70年代、过渡时期、后殖民时期三部文学界热门且公认具代表性的作品——《我城》《烦恼娃娃的旅程》和《后殖民食物与爱情》,解构了作品中“本土”“国家”和“全球”3个空间维度下再现的地理物象、空间想象、人物活动、地方文化,窥探其内部隐含的文化认同与身份意识问题。结果发现,由于香港社会历史和文化背景不断变迁等原因,香港的文化和身份意识处于不断重塑的状态。通过文本分析,发现香港文学作品中最早萌芽的是“本土”意识。西西的《我城》被认为是本土意识的发轫之作,其在港英政府和回不去的家这一夹缝中在“城”这一空间尺度上勾勒出浓浓的地方意识。其次,在中国恢复行使香港主权这一背景下,《烦恼娃娃的旅程》这一极具回归题材代表性的作品深刻地刻画了香港人在身份认同尺度升级过程中的迷惘。最后,也斯的《后殖民食物与爱情》通过“食物”为线索讲述了回归后的香港故事,为读者认识后殖民时期多元文化混杂下的香港社会提供了细致的观察。通过对三部文学作品的分析,发现港人经历了由殖民统治时期本土身份意识的觉醒以及对中国文化的归属,到回归过渡阶段身份意识的尺度升级及其不适,再到回归后多元文化的交织和协商,不仅在尺度上实现了由地方到国家再到全球化的身份意识塑造,而且在结构上存在中华文化、西方文化和香港本土文化不断协商与冲突的三重性。更为重要的是,通过文学地理视角的讨论,发现这样的文化和身份意识不是属于某个群体的特有特征,而是根植于香港社会的每一寸肌肤,不仅反映了小说作者对香港社会的细致观察,在一定程度上也反映了社会本身所面临的文化和身份困扰。