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1.
经过对白背飞虱不同虫态在同一生境内空间格局进行连续测定,表明其仅在田间初始低密度情况下呈现随机或均匀分布,一般均为聚集分布.分布参数显示白背飞虱种群为负二项分布,基本成分是个体群;低龄若虫有较高的聚集度;高龄若虫及成虫活动能力强,空间分布图式趋于个体;不同虫态平均密度(X)与方差(S2)用负二项分布曲线公式S2=X+X2/Kc配合良好;采用种群聚集均数(λ)测定,平均密度2.55头/丛是判定聚集原因的临界值.采用Iwao理论抽样模式,得出不同密度下的理论抽样数,并建立序贯抽样模式,可应用于田间抽样.  相似文献   

2.
应用泊松分布、负二项分布和奈曼分布三种理论分布模型,对取自长门岩岛的山茶种群的样方资料进行了分布格局的研究.结果表明,该种群的实际频数符合负二项分布,因此判定种群的分布格局为聚集分布.通过对种群的聚集强度指数的计算,求得各参数分别为二项参数(K)0.6291,扩散系数(C)17.7372,丛生指标(I)16.7372,Casie指标(1/K)1.5896,聚块性指标为(m/m)2.5896,均表明为强聚集分布.  相似文献   

3.
研究如下一类问题{utt+X^*1X1u+X^*2X2u=f(u){t=0:u=0,ut=h(x,y),其中f∈C^1(R^1),f(0)=0,h∈H^5(R^2)并具有紧支集,s>m/2(m+1),X1,X2是R^2上的光滑向量场并满足m阶Hormander条件,在以上假设下,得到了问题强解的存在性及正则性。  相似文献   

4.
给出了方差分量模型Y=Xβ+∑^mi=1Uiεi,U1U1’=…=UmUm’〉0中方差分量(o^21,…,o^2m)的非负二次同时估计(Y’A1Y,…,Y’AmY)可容许的一个必要条件。  相似文献   

5.
海南岛无翼坡垒种群调节研究   总被引:2,自引:1,他引:2  
通过对无翼坡垒种群的两个高度类群的个体群的高度与密度关系,以及种群生物量与种群稀疏规律的研究,基本上掌握了种群的调节规律.该种群3m高以下的个体群高度与密度的关系为D1=0.791026H1(-1.18716),3m高以上的个体群相应的关系为D2=1.83252H2(-2.26782),种群生物量基本上符合Logistic增长,种群稀疏规律Bmf=0.0248D(-1.4204).说明无翼坡垒种群调节的因素是种群密度,稀疏过程主要是自疏过程,他疏程度小,但却是一个必须引起注意的因素.  相似文献   

6.
部分取代苯定量结构-生物降解相关性(QSBR)研究   总被引:1,自引:0,他引:1  
采用Chems3D中量子化学MOPAC-AM1法计算了7种间苯胺类和8地苯酚的分子量高占有轨道能EHOMO、分子最低空轨道能ELUMO。用QSAR程序软件包查得分子体积Vm。结合分子连接性指数(^3X,^3X^v)对生物降解二级速率常数对数lgKb进行定量结构-生物降解相关性(QSBR)分析,通过回归分析,得到如下两个回归方程:lgKb=-0.832-0.118Vm+1.748^3X^v,n=15,R^2=0.832,SE=0.577,F=29.7,p=0.000。(1)lgKb=0.124Vm+1.749^3X^v,n=15,R^2=0.998,SE=0.5591,F=4148.99,p=0.000.(2)  相似文献   

7.
对Gauss-Markoff模型:Y=Xτ+e,e ̄(0,ο^2V),V≥0,τ的LSE的一种新的相对效率被提出来并得到了其下界,对方差分量模型:Y=Xτ+e,e ̄(0,mΣi=1ο^iVi),V=mΣi=1Vi≥0,τ的LSE的一种新的相对效率也被提出来并得到了独立于未知参数的下界。  相似文献   

8.
星豹蛛对棉花害虫的捕食效应研究   总被引:1,自引:0,他引:1  
研究了星豹蛛对棉花害虫的捕食效应.观察结果表明:星豹蛛对棉蚜、叶螨、棉铃虫、棉盲蝽的种群数量具有明显的控制作用.田间种群数量消长与棉花害虫密度表现为动态正相关(r=0.6124~0.8928).在试验条件下,其功能反应表现为随猎物密度的增加捕食量增大,随自身密度的增加捕食量减少.用Holing-Ⅱ型反应模型Na=a′TNt/(1+a′TnNt)能较好地拟合.星豹蛛对四种猎物的日最大捕食量依次为71.4,158.7,17.8,25.0头.在蚜螨猎物共存时,星豹蛛的选食作用较小,选择系数E=0.9896  相似文献   

9.
根据随机型概率分布(Poisson分布)中,方差(v)与均值(m)相等的性质,提出一个新的种群聚集度指标,,=m/n+m。指标不仅可用来判断昆虫种群的空间分布型,而且c’与m之间存在着线性关系。据此,提出了“c-m回归模型:c=a+bm。当c’与m线性相关显著时,a、b的不同组合型式就揭示了种群不同的空间分布型的信息。根据c-m模型,推导了序贯抽样方程和最大抽样数量的确定公式。  相似文献   

10.
本文研究了250Gev/c下π^+(K+)同质子,核碰撞的Bose-Einstein关联,用Q^-vKy(Q)分布拟合实验数据得出:当靶粒子为p时,r0=2.1fm;发靶为Al核时,r0=3.5fm;当靶为Au核时,r0=4.1fm。  相似文献   

11.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to  相似文献   

15.
Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications (up to 574.8 km/ h test speeds or 380 km/h commercial speeds) in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.  相似文献   

16.
17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.  相似文献   

19.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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