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A predator model with refuge and toxicity is studied. By constructing a suitable Dulac function, it is shown that there is no limit cycle in the first quadrant, thus the globally stability of the equilibrium is proved. Further more, the paper analyzes the influence of refuge, toxicity and harvesting. It is amazing that ① if the death rate of predator is big or the harvesting effort is big, the existence of the predator is unrelated with refuge; if the death rate of predator and the harvesting effort are small, and the refuge is small enough, the population of both species is increased as the increase of refuge;② if d2=0, the increase of d1 has no influence on the prey population, while the population of predator is decreased.

研究一类有避难所、毒素作用和外界捕获影响的捕食系统，通过构造恰当的Dulac函数，证明系统在第一象限没有极限环，从而证明了平衡点的全局稳定性；分析了避难所、毒素、捕获作用对该系统最终种群数量的影响，发现：①当捕食者的死亡率大或其被捕获得多时，两种群的绝灭与避难所的存在无关；当捕食者的死亡率小、被捕获得多且避难所足够小时，随着食饵避难所的增加，捕食者种群数量也随之增加；②当毒素d2=0时，毒素d1的增加对食饵种群最终数量没有影响，而使捕食者种群数量下降。

The seedlings of both genet population and clone population appeared random for their scarcity. The viability of population will be weakened because of the lack of seedlings.

基株种群和无性系种群幼龄级的分布格局均呈随机分布，与幼龄个体的数量稀少有关。

In the base of population and quantity of house-completed data of Xi'an, the paper builds an Auto-regressive Distributed Lag Model of population Geordie coefficient and quantity of house-completed, and analyzes the relationship between the two, which find that house construction is one cause of population suburbanization, but contrarily it's not.

本文以西安市人口和住宅竣工量为基础数据，建立人口基尼系数和住宅竣工量之间的自回归分布滞后模型，并对二者的关系进行了分析，发现住宅建设是西安市人口郊区化的动力之一，反之则不然。

The basal diameter, height of aerial stem, leaf length at middle stem, leaf width at middle stem, internode length at middle stem, internodes number and panicle length of 30 plants from every population were recorded. The statistics of morphological characters showed that the distribution trends of the averages of morphological characters are similar among populations. However, the coefficients of variation within population of 7 morphological characters were very different. The CV of internodes was largest and the CV of height was smallest within population. F-statistics showed that the differences of all morphological characters among populations were significant (P.01). But the differences among populations were different between different groups. The cluster analysis proved that all populations could be divided into three types: salty reed, freshwater reed and giant reed.

对来自每个种群的30个个体的基径、株高、中部叶长、中部叶宽、中部节间长、节间数、穗长7个形态特征的统计分析表明：各形态特征平均值在种群间的分布趋势相似，但变化幅度不同，株高、叶长等营养特征变化较大大，生殖特征穗长的变化较小；7个形态指标在种群内的平均变异度从大到小依次为中部节间长、中部叶宽、穗长、中部叶长、基径、节间数、株高，种群内的平均形态变异度与生境异质性有关；7个形态指标在种群间均差异显著，但多重比较分析显示显著差异主要存在于BZH、淡水生境种群和盐渍化生境种群之间，在相似生境种群间的形态差异不显著；以形态特征为依据的聚类分析支持将15个种群分为三类：盐生芦苇、淡水芦苇和巨型芦苇。

This study showed that population genetic diversity was much lower than other Gymnosperm and there was no distinct genetic differentiation among individuals in this population. In order to protect or preserve its genetic resource,it is suggested that the most individuals in the population should be selected as we can.

研究结果表明：AFLP方法是一种十分有效的检测种群遗传多样性的分子标记，既具有可靠性又有方便高效性；元宝山冷杉种群的遗传多样性水平很低，种群内各个个体间的相似性系数很大，遗传关系很近，无明显的遗传分化，这说明该种群的适应能力差、进化潜力有限，濒危程度很高；若要保护或保存这个物种的遗传资源，建议应该选择种群内尽可能多的个体进行保护。

This thesis gives some research on Chongqing city\'s population data by several models, which reveals the population problem. The last chapter analyzes the temporary habitant population by the statistics methods.

本文根据已有的人口数据对重庆市目前的人口状况给出了几方面的研究，建立了多个模型，初步了解了目前的人口问题，为未来人口的发展提出了一些设想。

The important elements of population dynamics were the population age structure,the pregnant rate,the reproductive indices and the population number of other species(little Chinese jird,northern three-toed jerboa and striped hamster).

结论影响种群数量变动的主要因素有种群年龄组成中幼年组的百分比、怀孕率、繁殖指数以及该地区子午沙鼠、三趾跳鼠和黑线仓鼠的数量。

In the study on the fern population structure, we through the analysis of the variation in height structure, leafstalk diameter structure and age structure in various forest communities, found the rule of variation of population, and discussed the reasons of variation of population structure, and explored the suitable habitat of various forest ferns.

在蕨类植物种群结构的研究中，我们通过对不同群落中蕨类植物种群高度结构、叶柄直径结构和年龄结构的研究，发现种群结构变化的规律，找出种群结构变化的原因，探索出各种蕨类植物种群的适生生境。

More physical mass requires more resources needed, meaning ever more material, energy and/or technical progress – or just more " Lebensraum "; hence the effects of severe over-population will arise even with steady or even declining population numbers! Therefore, the extremely mobile population of the U.S.A.

越多的有形形体，就需要越多的资源，也就意味着更多的物质，能量和/或技术进步—和更多的生存空间；因此，人口大量的过剩会影响社会的稳定，甚至人口数量的下降。

On the other hand,there has been so far no mapping method and software that can be used to map dominant-recessive markers obtained from F2 population of lepidopteran species.To resolve this problem,two-point and three-point maximum likelihood methods for mapping dominant-recessive markers using F2 population of this type of species were developed in this paper.At,the same time:we also gave a general method for constructing the gene linkage map of this type of species using F2 population.

另外，目前还没有任何方法和软件可以用杂交F2群体来作图鳞翅目类昆虫，如家蚕等连锁图谱，为了解决这一问题，本文发展了用F2群体作图这类昆虫连锁图谱的两点和三点极大似然法，同时还给出了大群体作图形态基因连锁图谱的一般方法。

Asked to design a simulation of this process, and give out the number of people out sequence..

要求设计一个程序模拟此过程，并给出出列人的编号序列。

The invention relates to an amplifier circuit containing a high-frequency transistor (1) and having a circuit (2) for adjusting the operating point, which provides a base current for the high-frequency transistor (1) according to the voltage released at a resistor (3) which is connected in the collector ring of the high-frequency transistor (1). The circuit (2) has a differentiating unit (20), fed by the supply voltage, which compares the voltage released at the resistor (3) with a reference voltage.

带有高频晶体管(1)的放大器电路具有一个用于工作点调整的电路(2)，其依赖于在连接在高频晶体管(1)的集电极电路中的电阻(3)上下降的电压为高频晶体管(1)提供基极电流，电路(2)具有一个由供电电压馈电的差分节(20)，其把在电阻(3)上下降的电压与基准电压比较。