原始蛋白结构与功能研究进展

近年来在生命起源研究方面,蛋白质起源研究来有很大进展,因为各种“组学（-omics）”的快速发展提供了关于蛋白质结构与功能的大量信息,据此可以初步推断原始蛋白的结构与功能特征．文章就该领域的最新研究进展进行了综述．     

The Cenozoic palaeoenvironment of the Arctic Ocean

The history of the Arctic Ocean during the Cenozoic era (0-65 million years ago) is largely unknown from direct evidence. Here we present a Cenozoic palaeoceanographic record constructed from >400 m of sediment core from a recent drilling expedition to the Lomonosov ridge in the Arctic Ocean. Our record shows a palaeoenvironmental transition from a warm 'greenhouse' world, during the late Palaeocene and early Eocene epochs, to a colder 'icehouse' world influenced by sea ice and icebergs from the middle Eocene epoch to the present. For the most recent approximately 14 Myr, we find sedimentation rates of 1-2 cm per thousand years, in stark contrast to the substantially lower rates proposed in earlier studies; this record of the Neogene reveals cooling of the Arctic that was synchronous with the expansion of Greenland ice (approximately 3.2 Myr ago) and East Antarctic ice (approximately 14 Myr ago). We find evidence for the first occurrence of ice-rafted debris in the middle Eocene epoch (approximately 45 Myr ago), some 35 Myr earlier than previously thought; fresh surface waters were present at approximately 49 Myr ago, before the onset of ice-rafted debris. Also, the temperatures of surface waters during the Palaeocene/Eocene thermal maximum (approximately 55 Myr ago) appear to have been substantially warmer than previously estimated. The revised timing of the earliest Arctic cooling events coincides with those from Antarctica, supporting arguments for bipolar symmetry in climate change.     

昌都:茶马古道上的枢纽及其古代文化--兼论茶马古道的早期历史面貌

昌都是茶马古道上的枢纽，是川藏道与滇藏道的交汇地。本通过敦煌藏写卷和考古资料对昌都的古代化及茶马古道的早期历史面貌进行了探讨。认为，早在唐宋汉藏茶马贸易兴起前，这条以昌都为枢纽分别通往今川、滇地区的道路就已经存在和繁荣，它不仅是一个卫藏与川滇地区古代先民们迁移流动的通道，同时也是川、滇、藏三地问古代明交流传播的重要孔道。从考古化遗迹和有关史实线索看，这条道路被开通和利用的历史至少可上溯到距今约4—5千年前的新石器时代晚期抑或更早。昌都一带则是这一明传播孔道上最重要的枢纽地区。     

城市化进程下的古建筑保护与发展——西递古村落保护的思考

西递古村落具有典型的皖南民居风貌特征.文章从理性观点出发,以实际调研作为依据,用安居古镇的保护为例,分析西递古村落的保护、利用与发展,归纳对古建筑保护的一些原则和方法.     

Inferring the historical patterns of biological evolution.

Phylogenetic trees describe the pattern of descent amongst a group of species. With the rapid accumulation of DNA sequence data, more and more phylogenies are being constructed based upon sequence comparisons. The combination of these phylogenies with powerful new statistical approaches for the analysis of biological evolution is challenging widely held beliefs about the history and evolution of life on Earth.     

通过猜词法附带习得词汇的研究综述

二语词汇附带习得是词汇拓展的一种重要方式,通过语境猜测词义则是词汇附带习得的常见途径。本文就词汇附带习得中语境猜词法的相关理论,有关实证研究以及猜词法应注意的问题进行了探讨,以期对二语词汇教学和学习有一定启示。     

Inferring nonlinear mantle rheology from the shape of the Hawaiian swell

The convective circulation generated within the Earth's mantle by buoyancy forces of thermal and compositional origin is intimately controlled by the rheology of the rocks that compose it. These can deform either by the diffusion of point defects (diffusion creep, with a linear relationship between strain rate and stress) or by the movement of intracrystalline dislocations (nonlinear dislocation creep). However, there is still no reliable map showing where in the mantle each of these mechanisms is dominant, and so it is important to identify regions where the operative mechanism can be inferred directly from surface geophysical observations. Here we identify a new observable quantity--the rate of downstream decay of the anomalous seafloor topography (swell) produced by a mantle plume--which depends only on the value of the exponent in the strain rate versus stress relationship that defines the difference between diffusion and dislocation creep. Comparison of the Hawaiian swell topography with the predictions of a simple fluid mechanical model shows that the swell shape is poorly explained by diffusion creep, and requires a dislocation creep rheology. The rheology predicted by the model is reasonably consistent with laboratory deformation data for both olivine and clinopyroxene, suggesting that the source of Hawaiian lavas could contain either or both of these components.     

Inferring the statistical interpretation of quantum mechanics from the classical limit

It is widely believed that the statistical interpretation of quantum mechanics cannot be inferred from the Schrodinger equation itself, and must be stated as an additional independent axiom. Here I propose that the situation is not so stark. For systems that have both continuous and discrete degrees of freedom (such as coordinates and spin respectively), the statistical interpretation for the discrete variables is implied by requiring that the system's gross motion can be classically described under circumstances specified by the Schrodinger equation. However, this is not a full-fledged derivation of the statistical interpretation because it does not apply to the continuous variables of classical mechanics.     

关于古塔变形的研究

基于2013年高教杯数学建模竞赛C题完成的对古塔的变形情况进行研究,针对古塔的倾斜、弯曲、扭曲等方面进行研究分析,并建立相应的数学模型。首先利用给空间平面拟合法确定古塔各层中心位置的通用方法,求解出古塔各层中心坐标;其次计算古塔的倾斜程度以及弯曲、扭曲的变形程度。最后,分析古塔的变形趋势。根据所建模型,得出古塔的变形趋势,对古塔的保护具有很大的指导意义和使用价值。     

Constructing a quasi-Legendre basis based on the C-Bézier basis

In the spaceГn = span{sint, cost, 1, t, t2, …, tn- 2[, a C-Bezier basis is constructed by an integral approach. However, the C-Bezier basis is not orthogonal. For some applications, we construct an orthogonal basis based on the C-Bezier basis, which has remarkable properties similar to that of the Legendre basis. Then we derive the transformation matrices that convert the C-Bezier basis and the orthogonal basis into each other. As an example of application, we apply this orthogonal basis to the degree reduction approximation of the C-Bezier curves.     

基于智能算法的面向目标Credal网络近似推理方法研究

针对大规模Credal网络的推理问题,提出了面向目标分别与遗传算法、蚁群算法、遗传-蚁群算法相结合的智能化近似推理方法.对这些推理方法进行了设计、实现和比较.结果表明:智能化近似推理方法获取最优解的效率较高,给决策人员提供影响查询变量特定状态极值概率的敏感Credal集,用于决定对极值决策的信任程度.     

C20分子异构体稳定性的HMO法推断

环型、碟型和笼型结构是迄今发现能量最低并且可以稳定存在的C20分子的三个异构体,通过HMO法的计算,对三者的稳定性从理论上进行了研究.计算结果表明,C20分子三个异构体的稳定性依次为:笼型结构;链型结构;碗型结构.     

热力学态函数的偏微商用可测量表示

每个可测量都有用一个相应态函数的偏微商来定义的定义式,由这些定义式和热力学有关定义、定律可推导出各种态函数的偏微商用可测量来表示的表示式,这是本文的核心内容.在推导过程中,笔者注意到方法的多样性和结果的等效性、繁简和难易性、系统和完整性,这样对于教学和研究是有益的.     

从古代分牛问题引起的思考

从不同角度对分牛问题提出六种解法，进而展示借牛法应用于数学实践的实例，表明数学学习是一种创造性的思维活动．同时，通过数学学习也可培养职业院校学生的数学能力和数学文化修养．     

用特征方程推导斐波那契数列的通项公式

斐波那契数列是一个古老的问题,吸引着无数人的兴趣,而其通项公式则是在这个数列诞生之后很长的一段时间后才用数学归纳法解决的.受微分方程中常系数线性微分方程的代数解法的启发,本文采取常系数线性递推方程的特征方程解法推导出斐波那契数列的通项公式。     

龙门山前缘上三叠统卡尼阶特征及其古环境、古气候意义

在龙门山前缘地区的上三叠统卡尼阶为海相沉积,整体以下部浅灰色、灰色鲕粒灰岩、海绵礁障积灰岩向上部的深灰色、灰黑色泥页岩、泥质粉砂岩的岩性、颜色突变为显著特征.在安县雎水、绵竹汉旺一带,在卡尼阶碳酸盐沉积的上部,多见海绵生物灰岩,在地表形成带状分布的海绵点礁(丘)群.通过对雎水地区海绵生物礁和江油马鞍塘、广元上寺、绵竹汉旺等剖面对应层位的野外实地调查和显微薄片分析,认为龙门山前缘的卡尼阶海绵等生物,生长在古地形复杂、水体能量低的较深水区域,海绵礁被卡尼期晚期沉积的黑灰色泥(页)岩、泥质粉砂岩所覆盖,二者界限明显,这套深色岩石在全区分布稳定;在上覆的泥质粉砂岩中见植物茎干及植物叶片化石.结合区域地质资料和阿尔卑斯等地研究资料,认为雎水等地的海绵死亡反映了卡尼期洪水事件,与构造运动有关的陆源物质的大量供给和巨型季风气候对卡尼期海绵礁(丘)的死亡负有主要责任.     

用特征方程推导斐波那契数列的通项公式

斐波那契数列是一个古老的问题,吸引着无数人的兴趣,而其通项公式则是在这个数列诞生之后很长的一段时间后才用数学归纳法解决的。受微分方程中常系数线性微分方程的代数解法启发,本文采取常系数线性递推方程的特征方程解法推导出斐波那契数列的通项公式。     

论中国古代书院产生的原因

书院是中国古代特有的教育组织形式.它以私人创办和组织为主,经历了千年之久的办学历史,并形成了一套独具特色的办学、授课、管理等教育模式,其丰富的教学经验和灵活多变的办学方式,为历代教育家所取鉴.作为中国封建社会的一种特殊的教育机构,书院成为华夏文明中最为光辉灿烂的组成部分,特别是在哲学和教育学的发展方面为中国历史写下了浓重的一笔.     

基于WinInet的FTP应用

探讨通过Internet访问企业内部局域网的数据问题．给出了在VB环境下，基于WinInet．dll开发FTP应用的方法．阐述了文件异步传输的实现手段，并给出了关键的实现代码．本系统经过客户测试证明是安全、稳定、可靠的。