查询词典 irrational fraction

To make a comprehensive view of metapopulation researches, we folly analyze and summarize the present concepts, theories and models of metapopulation in this paper, which primarily includes the dynamical models and simulation approaches of single and competitive metapopulations. Based on the Levin's patch occupant model, the center framework of metapopulation researches, primary principles and mechanisms are discussed. First, Levins rule: the fraction of empty patch will remain constant with habitat destruction as long as metapopulation survives. This rule implies that empty patches have determinant effects on persistence and conservation. Second. Allee effect of metapopulation is incurred by establishing difficulties and dispersal costs, which is important to the studies of reserve area and the minimum available metapopulation size. Third, we analyze the rescue effect that immigrants can reduce the extinction risk of the presented local population. Rescue effect can leads to the improvement of metapopulation sustainability and the decrease of fraction of empty patches. Fourth, the coexistence mechanism of two competing metapopulation is discussed, which suggests that competition-colonization trade off may be prevalent in competing systems. Finally, extinction debt ob tamed from coexistence mechanism is given, which depicts the lost of species richness in the future for the current habitat destruction. After theoretical discussion, we present two popular simulated approaches in metapopulations: probability transition model and stochastic process model.

为了能总观集合种群进展的全局并开展进一步的工作，首先对集合种群的已有概念、理论和模型做了全面的分析和总结；其次对集合种群的发展和概念进行了探讨，以集合种群模型的中心框架：Levins的斑块占据模型为基础，展开对其它原理、效应和机制的探讨；主要包括了Levins原理，即当生境进到破坏时，空斑块比例在集合种群灭绝前保持不变，然后还分析了Allee效应（集合种群的Allee效应主要是由于建群困难和扩散损失造成的）；第三，分析了援救效应：迁人个体可以降低斑块中现有局域种群的灭绝风险，援救效应会增强集合种群的生存力，使空斑块比例下降第四，探讨了两竞争集合种群的共存机制，即竞争－侵占妥协，其共存机制为空间生境中物种共存提供了有力的理论解释。

Establishment of non-contact nanoscale measurement of local electrical properties (local charge and local electric field).The local electron concentration of N atom in Al_xGa_(1-x)N with different Al mole fraction were calculated and the concentration was found to increase with the increase of Al fraction.

利用第一性原理方法分别计算了不同Al组分的Al_xGa_(1-x)表面的N原子周围局域电子密度和相应的态密度，模拟不同电子密度N KVV论俄歇价电子谱主峰强度N_与次峰的N_的比值，发现了比值随电子密度的增加而线性增加的现象。

The pH increase resulted in formation of a higher fraction of granules with a smaller diameter and a si- multaneous decrease in the fraction of the larger gran- ules Fig.

pH值增加导致形成一个更高部分颗粒的直径更小的硅同步下降，部分规模较大的颗粒 ules （图4）。

Softs for the adsorption experiment were sieved into the sand-sized fraction and sfttand clay-sized fraction.

其中吸附实验又分成砂粒土壤和粘粒土壤2个粒级分别实验。

Moreover, the vanadium of oxidisable fraction in rhizosphere soils had best correlation with that in stem leaf and to root the acid soluble fraction was the best.

根际土中可氧化态钒与茎叶相关性最好，酸可溶态与根系相关性最好。

Among those lipids, crude soy-bean phosphatides are most powerful. Crude egg yolk phosphatides and its alcoholic insoluble fraction and sodium or ammonium oleates are also effective; whereas the alcohol soluble fraction of egg yolk phosphatidesi.e.

二在上述情况中，有效的脂類為大豆磷脂、粗製雞卵璘脂及其不溶於酒精的部分、油脂酸鈉和油脂酸銨等；溶於酒精的雞卵磷脂和油脂酸鉀，並無作用。

The efficiency of mass transfer in 60% fraction of hole is higher than in 40% fraction of hole. When gas/liquid ratio is lower 10, the efficiency of mass transfer in new sieve baffle tray is higher than in traditional tray.A three-dimensional quasi-single phase computational fluid dynamics program with the RNG- turbulence model is presented for evaluating the performance of the new sieve baffle tray. The special feature of this model is taking into account the influence of heat transfer during the mass transfer and the influence of mass transfer in computing the flow field.

建立了以RNG模型为基础的三维拟单相流模型，该模型与其它研究者所建立的模型的最大进步是，前人在塔板流场的计算中没有考虑传质的影响，并且在传质过程中没有也没有考虑传热对传质产生的影响，实际上在传质过程中，抛开传热来计算和研究传质是不准确的，因为在传质过程中伴随着传热，并且传热和传质是互相影响、互相制约的，本文所建立的传热与传质模型，把传热和传质进行了有效的藕合。

And they end up predominantly in the fine particle fraction in the fly ash duringcombustion.When biomass sample is pretreated by using chemical fractionation method,the content of volatile alkali in fuels decreases clearly and large amount of available C1 andS is also leached.So,during combustion the vaporization amount of alkali reduces and theformation of fine particle fraction in the fly ash is limited.

而当样品在经水洗分离和酸洗分离的化学处理后，燃料中易气化部分的碱金属元素含量大幅减少，大量水溶态或酸溶态的S，Cl等非金属&催化性&元素同时也被分离脱除，从而导致燃料样品燃烧时的碱金属气化量下降，且在成灰过程中向细微颗粒转化的途径也受到较大的抑制。

In this paper we proposed a hypothesis of difference fiber volume fraction and presented expressions respectively. The fiber volume fraction of unit cell is not equal to that of each lamina, which need calculate eachly. The paper also advanced conception of weighted average of three cell's stiffness.

本文提出了差别纤维体积分数的假设，各个纤维束的纤维体积分数与单胞的纤维体积分数并不相等，需要分别进行计算，并分别给出了各纤维束的纤维体积分数计算式；还提出了三单胞弹性模量按比例叠加的思想，并给出了比例计算式，计算出了结果。

Unit fraction concepts: The description problems of language of halves are easier than the problem of symbol of 1/2. Students have the habit to deal with unit of things of all contents. When they face the problem of remaining to divide again, they would by oneself increase or reduce the thing of contents. And students were inclined toward each fraction appearing in the same contexts of assumption of ego to have the same deal of unit. When facing comparing problems could be influenced by intuition rules of Same A — Same B and solving problems incorrectly.

单位量概念的表现：一半语言叙述的问题的表现优於具二分之一符号的问题，较习惯用全部内容物当单位量，面对余量再分问题时会自行增减内容物改变单位量，会倾向於自我假设在同一情境中出现的各个分数具有相同的单位量，面对比较问题时受直观规律Same A─Same B的影响而错误解题。

You can snipe the second and third union leaders from this position.

您可以鹬第二和第三工会领袖从这一立场出发。

Aiming at the currently shortage of XML streams quality detecting, this paper proposes a new forecasting method of XML streams quality by least squares support vector machines, which is used the method of XML keys' vector matrix as windows, and vector product wavelet transform to multilevel decompose and refactor the XML streams series, that can fulfill real-time checking demand of XML quality, and ensure constraint, consist- ency and integrality. For even more adapting net load, it proposes a control strategy by weight and adaptive adjustment to ensure XML streams quality.

针对当前XML数据流质量检测存在的不足，提出构建XML键的矢量矩阵作为窗口，利用矢量积小波变换多级分解与重构XML数据流，再结合最小二乘支持向量机对XML数据流质量进行预测的一种方法，满足XML数据流质量重构时实时检测的要求，保证XML数据的约束性、一致性与完整性；为了更好的适应网络负载，采取加权与自适应窗口调整等调度策略充分保证XML数据流的质量检测。