Monodomain theory: experimental verification

The Néel thermal-activation theory of remanence in monodomain grains has been verified quantitatively in experiments on four ferrite micropowders and two natural rocks. Magnetization and demagnetization curves of thermal, isothermal, viscous, and anhysteretic remanences can all be predicted with reasonable accuracy when the Neél theory is generalized to include effects of grain interaction. Results with the natural materials indicate that interacting, single-domain grains or regions are the carriers of the magnetically hard natural remanence of some paleomagnetic rocks.     

Ecological competition between algae: experimental confirmation of resource-based competition theory

All possible outcomes of ecological competition, including stable coexistence, were observed in laboratory studies of two species of freshwater diatoms potentially limited by phosphate and silicate. The relative abundance of these nutrients determined the outcome of competition. The observed conditions of coexistence and competitive displacement agree with those predicted solely from the abilities of each species to acquire and utilize limiting nutrients. Coexistence occurred only when the growth rate of each species was limited by a different resource. These results may help explain the regional coexistence in nature of an otherwise paradoxically high number of algal species.     

基于新新贸易理论视角的农产品 加工企业出口决定因素研究

在经济全球化背景下,农产品加工企业成为农产品进出口的行为主体,为检验其出口决定因素,拓展了新新贸易理论的单一生产率异质企业模型,构建农产品加工企业出口决定因素的多重异质性模型,并利用中国工业企业数据库进行实证检验.结果发现:我国农产品加工企业走出去的程度较低,有出口的企业总体比例约为17％,出口为主的企业比例约为7％,纯出口的企业比例约为2.5％.总体来看,决定农产品加工企业是否出口以及出口产值占工业总产值比例高低的主要影响因素是企业区位、企业规模、技术创新、企业性质、企业级别和外资占总资本比例等多重异质性,受企业现有人力资本存量的影响不显著.     

权衡理论在企业资本结构战略中的应用

在资本结构战略中有很多理论指导,本文讨论权衡理论在资本结构战略中的应用.权衡理论认为,利息可以由税前抵扣,从而产生抵税收益,财务杠杆可以增加企业的价值,但是企业负债是有成本的,在企业负债规模较小时,企业市场价值与企业杠杆成递减函数关系,一旦财务杠杆持续扩展下去,企业的价值将要减少,企业存在一个最优的负债水平.     

Yeast: an experimental organism for modern biology

The yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe have become popular and successful model systems for understanding eukaryotic biology at the cellular and molecular levels. The reasons for this success are experimental tractability, especially in applying classical and molecular genetic methods to associate genes with proteins and functions within the cell.     

Cerebral concussion in the monkey: an experimental model

A statistically significant experimental model has been developed for reproducing head injury by impact in the monkey. Results with 80 monkeys subjected to occipital impact under specified conditions ( duration of phenomena, 1 to 10 milliseconds) enable the construction of curves relating the production of experimental cerebral concussion in 10, 50, and 90 percent of the monkeys to the average impulse of the blow in pounds-seconds, as well as to the average linear acceleration of the head. These curves are proposed as a baseline from which blows to various parts of the head, as well as nonimpacting impulsive loads, can be studied under various conditions of protection and according to varioucs time regimes.     

关于区域地价平衡的研究

随着我国国民经济的迅速发展，迫切需要我国的土地管理体系跟上形势的发展，而在我国的土地管理体系中，地价管理乃是重中之重，众所周知，现阶段我国各地经济发展水平差异较大，地价的管理水平更是参差不齐，鉴于以上情况，我们详尽地论述了关于“区域地价平衡”的论点，该论点分为3大部分，即宏观地价平衡，中观地价平衡，微观地价平衡，分别针对我国不同层次上地价管理中存在的不同问题提出了详尽的见解。     

家禽日粮中电解质平衡的研究进展

阐述家禽电解质平衡与酸碱平衡的关系、 DEB计算方法、电解质平衡对生产性能、蛋壳质量、营养物质利用率、肉鸡腿病、肉鸡猝死症和腹水症的影响     

五味祛脂颗粒辅助降血脂动物实验研究

通过辅助降血脂动物试验研究,研究五味祛脂颗粒对高血脂症大鼠的降血脂作用.采取喂食高脂饲料的方法建立大鼠高血脂症模型,取高血脂模型大鼠40只,随机分为五味祛脂颗粒低、中、高剂量组以及模型对照组、非诺贝特阳性对照组.各组分别给予相应的受试物,每日1次,连续给样30 d,眼内眦取血,观察大鼠体重及血清TC、TG、LDL-C、...     

Accretionary processes in the early solar system: an experimental approach

Micrometer-size silicate flakes do not accrete during impacts in the velocity range 1.5 to 9.5 kilometers per second. Conventional accretionary theories for silicate bodies are applicable only to particles whose orbits are similar. Metal-silicate fractionation in the solar system may have been affected by differences in the accretionary behavior of the metal and silicate particles.