木材中吸着水介电弛豫的扩散方程及其形式解

该文根据其作者提出的关于木材细胞壁无定形区域中吸着水的介电弛豫机构模型，就木材细胞壁无定形区域中吸着水的束缚能Ｕ和活化焓ΔＨ，束缚能Ｕ和含水率Ｗ之间的相关关系，束缚能的定量表达式，吸着水的总势能等方面作了一些讨论．在此基础上，依照Ｋｉｒｋｗｏｏｄ Ｆｏｕｓ理论，从Ｓｍｏｌｕｃｈｏｗｓｋｉ方程出发，建立了描述在介电弛豫过程中，木材细胞壁无定形区域中的吸着水分子切断同木材吸着点之间形成的氢键结合进行回转取向运动的扩散方程．同时，讨论了吸着水扩散方程在特定情形下的形式解     

斜拉桥柔性拉索力学状态的探讨

系统地讨论了斜拉桥柔性拉索索形方程在各种不同已知条件下状态变量的求解公式和步骤,提出了“相似算法”,较为精确地考虑了斜拉索的几何非线性。而这种精确性,对于计算超长拉索具有重要的工程实际意义。     

安徽省几种旱地土壤磷吸附曲线的研究

本文运用Langmuir公式,研究了安徽省几种代表性的旱地土壤:砂姜黑土、粘盘黄褐土、和黄红壤的磷吸附曲线,探索了最大吸附量b、吸附能常数K和吸附量Y。结果表明,最大吸附量和吸附能常数K能较好地反映土壤的固磷与供磷状况,可为合理施用磷肥提供依据。     

伯努利方程的扩展讨论

能量方程在水利工程中应用广泛,解决了很多工程实际问题,本文从能量方程的适用条件入手,重点讨论了能量方程的扩展方程。     

Architecture of a charge-transfer state regulating light harvesting in a plant antenna protein

Energy-dependent quenching of excess absorbed light energy (qE) is a vital mechanism for regulating photosynthetic light harvesting in higher plants. All of the physiological characteristics of qE have been positively correlated with charge transfer between coupled chlorophyll and zeaxanthin molecules in the light-harvesting antenna of photosystem II (PSII). We found evidence for charge-transfer quenching in all three of the individual minor antenna complexes of PSII (CP29, CP26, and CP24), and we conclude that charge-transfer quenching in CP29 involves a delocalized state of an excitonically coupled chlorophyll dimer. We propose that reversible conformational changes in CP29 can "tune" the electronic coupling between the chlorophylls in this dimer, thereby modulating the energy of the chlorophyll-zeaxanthin charge-transfer state and switching on and off the charge-transfer quenching during qE.     

Persistent cultural systems

I have indicated here some features of a kind of entity which I have called a cultural identity system, and I have focused on a variety of this general type-the persistent system. In general terms it is best described as a system of beliefs and sentiments concerning historical events. I suggest using the term "a people" for the human beings who, at any given time, hold beliefs of this kind. These are phenomena with which we have been long familiar, but they have not been systematically studied by any but a few investigators. I have emphasized that a persistent system is a cumulative cultural phenomenon, an open-ended system that defines a course of action for the people believing in it. Such peoples are able to maintain continuity in their experience and their conception of themselves in a wide variety of sociocultural environments. I hold that certain kinds of identifiable conditions give rise to this type of cultural system. These may best be summarized as an oppositional process involving the interactions of individuals in the environment of a state or a similar large-scale organization. The oppositional process frequently produces intense collective consciousness and a high degree of internal solidarity. This is accompanied by a motivation for individuals to continue the kind of experience that is "stored" in the identity system in symbolic form. The persistent identity system is more stable as a cultural structure than are large-scale political organizations. When large-scale states disintegrate, they often appear to decompose into cultural systems of the persistent type. Large-scale organizations also give rise to the kind of environment that can result in the formation of new persistent systems. It is possible that, while being formed, states depend for their impetus on the accumulated energy of persistent peoples. A proposition for consideration is that states tend to dissipate the energy of peoples after transforming that energy into state-level integrations, and then regularly break down in the absence of mechanisms for maintaining human motivations in the large-scale organizations that they generate.     

国内外海洋能发电测试场研究现状

海洋能作为一种重要的海洋资源和清洁能源,其开发和利用是国家发展战略的必然要求。海洋能发电测试场能对海洋能装置进行实海况并网试验,是海洋能装置从工程样机走向规模产业化应用的关键环节。介绍了目前国外大型的波浪能、潮流能测试场的建设与运行情况,并做了简要的对比分析;还介绍了当前我国在海洋能试验与测试场建设方面的进展、现状及相关技术。探讨了我国海洋能发电进行并网测试的必要性,指出建设海洋能发电测试场是保证我国海洋能资源的有效利用途径。     

动态边界条件下一类强阻尼波动方程解的爆破

考虑了一类具有Kelvin-Voigt阻尼的波动方程.运用位势井理论,通过构造稳定集和不稳定集,结合能量分析的方法,首先证明了当初值属于稳定集时,该问题存在整体解;其次证明了强阻尼项的存在使得问题的解一致趋近于零,且具有指数衰减速率;最后给出了解在有限时间爆破的充分必要条件.     

木材的热力学函数

从木材的微观结构出发，并把木材视为一个热力学系统。应用晶态固体理论和热力学关系，在木材比热容理论表达式的基础上，导出了木材的状态方程，内能，熵等热力学函数。     

Priestley-Taylor模型参数修正及在蒸散发估算中的应用

准确估算和模拟植被蒸散可为提高水分利用效率、合理配置水资源,及生态系统可持续经营管理提供科学依据。Priestley-Taylor模型因其所需参数较少而在蒸发散估算中得到广泛应用。介绍了该模型的计算方法和发展情况,总结分析了Priestley-Taylor模型参数的各种修正方法及适用条件,简要介绍了其在农田生态系统和森林生态系统蒸散估算研究中的应用情况,并指出了该模型今后的应用和发展方向,以期为Priestley-Taylor模型的进一步深入研究和广泛应用提供参考。表1参42     

Wet electrons at the H2O/TiO2(110) surface

At interfaces of metal oxide and water, partially hydrated or "wet-electron" states represent the lowest energy pathway for electron transfer. We studied the photoinduced electron transfer at the H2O/TiO2(110) interface by means of time-resolved two-photon photoemission spectroscopy and electronic structure theory. At approximately 1-monolayer coverage of water on partially hydroxylated TiO2 surfaces, we found an unoccupied electronic state 2.4 electron volts above the Fermi level. Density functional theory shows this to be a wet-electron state analogous to that reported in water clusters and which is distinct from hydrated electrons observed on water-covered metal surfaces. The decay of electrons from the wet-electron state to the conduction band of TiO2 occurs in 相似文献   

输气管道静态模拟及管道末段储气量计算

在对稳定流动理论分析的基础上，建立了较真实反映管内气体稳定流动的基本数学模型，该模型包括连续性方程、动量方程、能量方程和状态方程。采用四阶龙格-库塔法编制了该模型的通用数值计算程序，以陕甘宁至北京长输管道为例进行验证，并在此基础上，对稳定流动工况输气管道末段储气量进行了详细研究和计算。     

秸秆燃气合成甲醇的热力学试验研究

采用热化学方法,将玉米秸秆裂解为生物质燃气,并对该燃气进行优化试验,制备出合成气.在直流流动等温积分反应器中,采用国产C 301铜基催化剂,对玉米秸秆合成气催化合成甲醇进行了试验.运用SHBWR状态方程,计算了加压下秸秆合成气合成甲醇反应体系的密度及状态方程参数.     

Age estimates of globular clusters in the Milky Way: constraints on cosmology

Recent observations of stellar globular clusters in the Milky Way Galaxy, combined with revised ranges of parameters in stellar evolution codes and new estimates of the earliest epoch of globular cluster formation, result in a 95% confidence level lower limit on the age of the Universe of 11.2 billion years. This age is inconsistent with the expansion age for a flat Universe for the currently allowed range of the Hubble constant, unless the cosmic equation of state is dominated by a component that violates the strong energy condition. This means that the three fundamental observables in cosmology-the age of the Universe, the distance-redshift relation, and the geometry of the Universe-now independently support the case for a dark energy-dominated Universe.     

一种基于响应的振动系统参数识别的迭代方法

研究了振动反问题,提出了一种适用于振动系统参数识别的迭代方法。该方法把振动控制方程转化为状态方程,基于振动系统的时域响应,通过构造一种矩阵迭代算法来反演系统参数。数值算例表明本文方法具有较快的收敛速度和较高的精度。     

Condensed-matter energetics from diatomic molecular spectra

Analyses of molecular spectra and compression data from crystals show that a single function successfully describes the dependence on interatomic separation of both the potential energy of diatomic molecules and the cohesive binding energy of condensed matter. The empirical finding that one function describes interatomic energies for such diverse forms of matter and over a wide range of conditions can be used to extend condensed-matter equations of state but warrants further theoretical study.     

粘钢加固钢筋混凝土梁可靠性分析

为了按照《建筑结构可靠度设计统一标准》（GB50068—2001）要求的可靠指标进行钢筋混凝土梁的粘钢加固设计,根据现行《混凝土结构设计规范》（GB50010—2002）和Chen—Teng模型建立了钢筋混凝土粘钢加固梁的极限状态方程,通过一次二阶矩法计算了由使用功能改变引起的粘钢加固混凝土梁抗弯可靠性指标．计算结果表明按此方程设计的粘钢加固混凝土梁可靠指标基本大于3．7,满足《建筑结构可靠度设计统一标准》（GB50068—2001）的要求,可以按此方法进行混凝土梁的粘钢加固．     

Synchrotron X-ray Diffraction Measurements of Single-Crystal Hydrogen to 26.5 Gigapascals

The crystal structure and equation of state of solid hydrogen have been determined directly to 26.5 gigapascals at room temperature by new synchrotron x-ray diffraction techniques. Solid hydrogen remains in the hexagonal close-packed structure under these pressure-temperature conditions and exhibits increasing structural anisotropy with pressure. The pressure-volume curve determined from the x-ray data represents the most accurate experimental measurement of the equation of state to date in this pressure range. The results remove the discrepancy between earlier indirect determinations and provide a new experimental constraint on the molecular-to-atomic transition predicted at higher pressures.     

The relationship between high-temperature superconductivity and the fractional quantum Hall effect

The case is made that the spin-liquid state of a Mott insulator, hypothesized to exist by Anderson and identified by him as the correct context for discussing high-temperature superconductors, occurs in these materials and exhibits the principles of fractional quantization identified in the fractional quantum Hall effect. The most important of these is that particles carrying a fraction of an elementary quantum number, in this case spin, attract one another by a powerful gauge force, which can lead to a new kind of superconductivity. The temperature scale for the superconductivity is set by an energy gap in the spin-wave spectrum, which is also the fundamental measure of how "liquid" the spins are.     

土壤信息熵和热力学熵的联系及其肥力意义

在统计力学中,熵是混乱度的度量。它一方面与土壤信息出现概率有关,一方面和土壤热力学系统中的自由能有关。土壤信息在约定前提下出现概率可反映土壤整体肥力水平,土壤热力学熵则更直接地反映了土壤系统的作功能力,是高度综合的土壤肥力指标。土壤系统耗散结构从热力学机率大的状态过渡到机率小的状态,是一个不断输入能量和获得信息的过程,为土壤肥力研究另辟蹊径。