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in patches相关的网络例句

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This paper consists of three parts: Firstly, we discuss a nonautonomous -species two-patches cooperative Lotka-Volterra diffusion system. Using Brouwer fixed-point theory and Liapunov function, under some conditions, we obtain that the system has a unique globally asymptotically stable positive periodic solution. Secondly, we consider a kind of nonautonomous predator-prey model, in which preys are with stage structure and the predator are with two patches.

中文摘要:本文分三部分讨论三类生态模型周期解或概周期解的存在性及全局渐近稳定性等内容:第一部分讨论了两斑块种群的互惠Lotka-Volterra扩散系统,运用不动点理论和构造Liapunov函数,得到了系统存在唯一一个全局渐近稳定的正周期解的充分条件。

Methods In 98 cases of traumatic tympanic membrane perforations, 66 patients were treated with cotton patches soaked with bFGF applied to the surfaces of perforated tympanic membrane and bFGF eardrop was driped onto the patches twice per day, other 22 patients without the use of bFGF as the control.

随机将外伤性鼓膜穿孔分为两组:治疗组66例,用浸湿bFGF的压薄无菌棉片贴补,并每日两次用bFGF喷耳;对照组22例仅用贴补治疗。

The introduction of the Field Grey Assault Gun uniform in 1940 led to field grey collar patches similar to the panzer type patches shown above. These were worn by self-propelled artillery crews.

引进外地灰色殴打枪制服在1940年导致领域的灰领补丁类似该型装甲补丁上面显示的,这些人所穿的自行火炮的船员。

The results showed that suitable grassland patches occupied 20% in 100 investigated grassland patches.

结果表明:在所调查的100个绿地斑块中,适宜绿地斑块占20%;基本适宜的绿地斑块占22%;不适宜的绿地斑块占58%。

To keep certain number of greater patches through protection and restoration in urban area is meaningful;(2) small greenland patches with diverse structure may promote the heterogeneity of urban landscape, and serve as colonial land and stepping stones for certain populations, and create rich types of habitats and ecological niches. So laying small patches in urban environment is also important. Incorporation of the coarse grain and fine grain, aggregation and outliner of landscape elements may creates better landscape patterns;(3) many literatures have showed that good landscape connectivity benefits the longer persistence of species and the conservation of biodiversity.

大的绿地斑块有多种作用,通过城市地区自然景观斑块的保护或城市绿地的建设,在城市中维持一定的较大规模的绿地斑块是有积极意义的;(2)结构不同的小的绿地斑块可增加城市的景观异质性,为生物提供迁徙地、扩散暂歇地,创造丰富的生境资源和生态位,因此,结合大的绿地斑块的建设,同时布置小的绿地斑块作为补充,粗粒、细粒结合,集聚、分散结合是形成优良绿地景观格局的途径;(3)诸多的文献已显示,好的景观连接性有利于物种持续较长的时间,从而有利于生物多样性的保护。

Bieti lost its habitat continuously in recently decades associated with the extension of rangelands and farmlands, as well as firewood collection etc. The monkey live mainly in primary fir forest and the mixed conifer forest, to evaluate the status of the monkeys' habitat, we employed GIS and RS software to identify the habitat types with five Landsat TM/ETM+ satellite imagery in winter of 1986, 1992, 1997, 2001 and 2006 years respectively. The work resulted in: 1 the size of summer grazing lands, farmlands, and fir forest was 13 100 hm2, 6 400 hm2, and 30 500 hm2 in 2006 respectively; 2 during the past 20 years (1986-2006), the size of fir forest (including primary fir forest and the mixed conifer forest) decreased by 14.6%(5 200 hm2), summer grazing lands and farmlands increased by 47.2%(4 200 hm2) and 14.3%(800 hm2) respectively; and 3, during the past 20 years, the number of firry forest patches increased by 68.4%, the mean size of firry forest patches decreased by 49.3%(from 15.1 to7.6 hm2), the largest patch index of firry forest decreased 54.9%; the patch richness had no change, but the Shannon's diversity index and the Shannon's evenness index increased by 2.7% respectively.

为了评估该物种的栖息地现状和变化情况,我们通过野外调查工作,应用GIS和RS技术,分别解译了1986年、1992年、1997年、2001年和2006年的Landsat TM/ETM+冬季卫星影像,并对解译结果进行了计算和分析,得到了以下西藏种群栖息地的主要结果:1)现有暗针叶林(包括原始针叶林和针阔混交林)面积是30 500 hm2,夏季牧场面积是13 100 hm2,农田面积是6 400 hm2;2)在过去20年间(1986-2006年),暗针叶林面积减少了14.6%(5 200 hm2),夏季牧场面积增加了47.2%(4 200 hm2),农田面积增加了14.3%(800 hm2);3)在过去20年间,暗针叶林的斑块数量增加了68.4%,平均斑块面积下降了49.3%(从1986年的15.1 hm2下降到2006年的7.6 hm2),最大的斑块指数下降了54.9%;景观丰富度并没有变化,但Shannon多样性指数和Shannon均匀度指数分别增加了2.7%。

Result The levels of sICAM1 and IL12 in skin tissue fluid were significantly higher in vitiliginous skin than that in nonvitiliginous patches in patients with common type vitiligo, whereas there was no significant difference between the two kinds of patches in patients with segmental type vitiligo.

结果:寻常型白癜风患者局部白斑处皮肤组织液sICAM1及IL12水平较非白斑处显著增高;而节段型白癜风白斑与非白斑处皮肤组织液sICAM1及IL12水平无显著性差异。

Result The levels of sICAM-l and IL-12 in skin tissue fluid were significantly higher in vitiliginous skin than that in non-vitiliginous patches in patients with common type vitiligo, whereas there was no significant difference between the two kinds of patches in patients with segmental type vitiligo.

结果:寻常型白癜风患者局部白斑处皮肤组织液sICAM-1及IL-12水平较非白斑处显著增高;而节段型白癜风白斑与非白斑处皮肤组织液sICAM-1及IL-12水平无显著性差异。

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。

Firstly, according to study dynamic changes of the elements structures in succession about natural and artificial forest, then summarized regular patterns;at the same time.based on the study of Coupling Relationship between structure and function of water conservation forest established the ideal structures from the stand level and the watershed level. The ideal structures from the stand level: uneven-aged, double layer and mixed structure, and trend to natural forest. The watershed level followed the same principle, that is double layer patches, uneven-aged forest well-distributed and to build up different forest patches in watershed.

首先,经过对北京山区水源林天然林和人工林结构要素的演替动态研究,提出其发展规律,同时依据水源林结构与功能耦合关系研究,从林分层次和流域层次上分别构建了水源林的理想结构,其中,林分层次上水源林的理想结构为:异龄、复层、混交的结构状态,林分结构趋于天然林结构的特征;在流域层次上水源林的理想结构为也应形成&复层&、&异龄&、&混交&的结构,即:在流域各水源林斑块间形成林冠层复层、斑块内部乔木、灌木、草本层的复层;不同水源林年龄面积上的均匀分布;形成不同水源林斑块间的镶嵌分布。

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推荐网络例句

By the time of its fall, most of the prisoners were writers who had written against the corruptions of the government.

到它被攻陷的时候,里面多数的犯人是写了反对政府贪污文章的作家。

The most obvious variation to ovum morphological character was that the color was changed from light green to sepiaceous in embryonic development, and all the ovums were almost hatched after 96h.

在胚胎发育过程中卵的形态特征最明显的变化是颜色从淡绿到深褐色,卵在发育96h后卵基本全部孵化。

There was a conflict between plebs and patricians in ancient Rome in 494BC.

在公元前494年,罗马发生了一次平民反对贵族的斗争。