简介：Bambooasanimportantbiologicalresourcehasbecomeanalternativetowoodgradually,butthevariationinmechanicalpropertiesleadstodifficultyinitsusetosomeextent.Sodeepunderstandingofthenatureinbambooisneededtosatisfytheutilizationeffectively.Aswehaveknown,thedensityisoneofmechanicalpropertiesofbamboo.Therefore,thispaperstudiedthevariationinbamboodensitywiththeweighingmethod.Theresultsshowedthatthedensitydecreasesgraduallyfromtheoutertotheinn...

简介：Araliaclata是在东北中国的重要的经济种。为determung最佳幼苗密度的实验在辽宁省的试验性的福雷斯特农场的托儿所被做。Qingyuan县，在1997。为六密度的4个重复实验的结果被单个因素用变化分析分析。幼苗密度在直径的生长上有大效果(在英尺)并且高度。合适的幼苗密度forAraliaelata决心是55鈥?5stems/m2，或330000390000hm2。因此，密度能保险单个幼苗鈥檚质量和幼苗的最大的生产率。

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简介：在这个工作，我们主要为一个拓扑地动态的系统调查复杂性的问题(X，f)。如果，我们证明f有一个完整的措施中心在那里存在X的一个可计算的底令人满意为任何i，在X有y以便N(y，Ui)积极Banach上面的密度被设置。而且，我们考虑混乱性质(X，f)。如果它及物然而并非最小，我们证明如此的一个系统在拿窄小的街道的意义是混乱的。

简介：Traditionally,bonestructureandbonemassareassessedbyobservingtherari-fiedboneonstandardx-rayfilms.However,smallchangesinbonemasscannotbedetectedeffectively.Bythetimelossofbonemasscanbedetectedonthex-ray,thediseaseisalreadyinanadvancestage.Atleast30%ofbonemustbelostbeforeproblemslikeosteoporosiscanbediagnosed.

简介：Background:Oneofthemostimportantdriversofforestbiodiversityisconspecificnegativedensitydependence(CNDD),areductioninperformancewhenconspecificdensitiesarehigh.WhilethemajorityofCNDDresearchhasfocusedontropicalforests,evidenceismountingthatCNDDmayalsoplayanimportantroleintemperateforests.Tofurtherexplorethepotentialreachofthisphenomenon,weinvestigatedCNDDinAmericanbeech(Fagusgrandifolia)inamaturemid-Atlanticforest.Methods:Weusedbivariatepointpatternanalysestoexaminespatialrelationshipsbetweenlargebeechtreesandconspecificsaplings,andwealsocontrastedthesepatternswithcomparablepatternsforheterospecifics.Inaddition,toaddressthepossibilityofdispersallimitationandtheassociatedeffectsonspatialpatterns,weanalyzedseedlingdensityasafunctionofadultconspecificabundance.Results:Wefoundthatbeechsaplingsweremorerepeledfromlargeconspecificsthanlargeheterospecifics,despitethefactthatbeechseedlingdensitywaspositivelycorrelatedwithbeechbasalarea.However,saplingsofothercanopytreespecieswerealsorepeledfromadultbeechtrees,suggestingageneralsuppressiveeffect.Nonetheless,thediscrepancybetweenbeechseedlingandsaplingdensitiesbeneathadultconspecificssuggeststhatbeechseedlingsurvivalrateswerereducedinvicinityofconspecificadults.Conclusions:Regardlessoftheextenttowhichbeechinhibitsheterospecifictrees,anegativeeffectonconspecificrecruitsmaybecriticalforbiodiversitymaintenance.Withoutthisconspecificsuppression,adenselayerofshade-tolerantbeechsaplingscouldformbeneathadultbeechtrees.Ifthisweretooccur,beechwouldhaveasubstantialhead-startfolowingcanopydisturbance,andthislate-successionalspeciescouldpotentialydominateastandinperpetuity,throughrepeateddisturbancecycles.

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简介：土壤体积密度的测量为理解土壤的物理、化学、生物的性质是重要的。精确、快速的土壤体积密度测量技术在农业试验性的研究起一个重要作用。这评论是存在测量方法的一篇全面摘要并且为未来开发评估他们的优点，劣势，错误的潜在的来源，和方向。这些技术能广泛地作为直接、间接的方法被分类。直接方法包括核心，土块，和挖掘采样，而间接方法包括放射和回归途径。核心方法最广泛地被使用，但是为采样使用多重土壤深度耗时、困难。coring柱体的尺寸使用了，操作员经验，采样深度，并且在原处显著地玷污潮湿内容影响它的精确性。土块方法是合适的因为有重黏土的使用，和它的精确性依赖于设备刻度，弄干时间，和操作员经验，但是这个过程复杂、耗时。挖掘技术最通常被用来评估森林土壤的体积密度，但是把他们不能与大毛孔在土壤被使用，他们的测量精确性被土壤质地和分析的类型强烈影响的主要限制选择。间接方法看起来比直接途径有更大的精确性，但是有更高的费用，是更复杂的，并且要求更大的操作员经验。一如此的途径使用gamma放射，和它的精确性被土壤深度强烈影响。当他们能做间接大小，回归方法是节俭的，但是这些取决于土壤质地和有机物内容和地理、气候的性质的好、优秀数据。另外，它的精确性象大多数另外的途径一样，与采样深度减少。

简介：Weraiseandpartlyanswerthequestion:whetherthereexistsaMarkovsystemwithrespecttowhichthezerosoftheChebyshevpolynomialsaredense,butthemaximumlengthofazerofreeintervalofthenthChebyshevpolynomialdoesnottendstozero.Wealsodrawtheconclu-tionthataMarkovsystem,underanadditionalassumption,isdenseifandonlyifthemaxi-mumlengthofazerofreeintervalofthenthassociatedChebyshevpolynomialtendstozero.

简介：Twokindsofgaseswereusedtoinvestigatetheinfluenceofgasdensityonthehydrodynamiccharacteristicsinabubblecolumn.Itcanbefoundoutthathighergasdensityleadstosmallerbubblediameterandtheflowpatternsaredifferentforthebothgases.Energybalancemechanismsareanalyzedbyconsideringthegasdensitydifference.Modelsweredevelopedtopredicttheaveragebubblediameterwithgoodaccuracy.

简介：ThispaperdefinestheuppercapacitydensitiesofthesubsetsofR^n,getsuniformlowerboundoftheuppercapacitydensitiesforH^s-almostallpointsoftheHausdorffs-setsortheanalyticsetswithHausdorffdimensionsinR^n,whichimprovestheresultsofWenZhiyingandZhangYiping'spaperin[1].

简介：Arbuscularmycorrhizafungi(AMF)arevitalintheregenerationofvegetationindisturbedecosystemsduetotheirnumerousecologicaladvantagesandthereforearegoodindicatorsofsoilandecosystemhealthatlarge.Thisstudywasaimedatdetermininghowtheseasonal,vegetationcoverdensity,edaphicandanthropogenicfactorsaffectAMFrootcolonization(RC)andsporedensity(SD)inDesa’adryAfromontaneforest.AMFRCandSDintherhizosphereoffivedominantwoodyspecies,Juniperusprocera,Oleaeuropaea,Maytenusarbutifolia,CarissaspinarumandDodonaeaangustifoliagrowinginDesa’aforestwerestudiedduringtherainyandthedryseasonsinthreepermanentstudyvegetationcoverdensityplots(dense,medium,andpoor).Eachplot(160×40m2)hastwomanagementpractices(fencedandunfencedplots)ofarea.A100gsampleofrhizospheresoilfrommoisturefreecompositesoilwasusedtodeterminesporedensity.Sporedensityrangedfrom50to4467spores/100gsoil,andallspecieswerecolonizedbyAMFwithinarangeof4–95%.Glomuswasthedominantgenusintherhizosphereofallspecies.VegetationcoverdensitystronglyaffectedSDandRC.TheSDwassignificantlyhigher(p<0.05)inthepoorvegetationcoverdensitythanintheothertwoandlowestinthedensecover;rootcolonizationshowedthereversetrend.Managementpracticessignificantly(p<0.05)influencedAMFSDandRC,withthefencedplotsbeingmorefavoured.Seasonssignificantly(p<0.05)affectedRCandSD.MoreRCandSDwereobservedinthewetperiodthanthedryperiod.CorrelatingAMFSDandRCwithsoilphysicalandchemicalpropertiesshowednosignificantdifference(p>0.05)exceptfortotalnitrogen.Disturbance,vegetationcoverdensity,seasonandtotalnitrogenaresignificantfactorsthatcontrolthedynamicsandmanagementinterventionstomaintaintheforesthealthofdryAfromontaneforests.

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简介：一座大楼城市的流动上的密度的效果与RNGκ用一个CFD模型被调查-ɛ骚乱闭合计划。有不同的造的27个案例是密度参数(例如，大楼和街峡谷纵横比)数字地被模仿。当大楼的密度参数变化，不同流动政体出现。当街峡谷相对狭窄、高时，在垂直方向的二个相反旋转的旋涡被产生。沿着街的风速被大楼的长度主要影响。然而，以一座单个大楼的密度参数发现或概括街峡谷流动的特征是很困难的。这是因为复杂流动模式由于旋涡结构和旋涡数字的变化出现。平均卷的涡度大小是很好的指示物尽管有流动的强壮的相关性，在大楼的密度参数的变化上反映流动特征。平均卷的涡度大小是大楼的长度和街峡谷宽度的强壮的功能的多线性的回归表演。大楼的长度的增加减少街峡谷的涡度流动，当时，在街上，峡谷宽度增加的增加涡度。

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简介：Objective:ThisstudyaimstoexploretheassociationbetweenthedensityofHimalayanmarmot(Marmotahimalayana)andclimaticfactorssuchastemperature,precipitation,humidity,vapourpressure,sunshinepercentage,windvelocity,whicharecloselyassociatedwithglobalclimatechange,andtoprovideareferenceforplaguepreventionandcontrol.Methods:WeconductedaregressionanalysistofindthepossibleclimatefactorsassociatedwiththedensityofHimalayamarmot,andanalyzedtheresponsecharactersofHimalayanmarmottoclimatechange.Results:Dailyprecipitationdays(>=0.1mm)andsunshinepercentageweresignificantlyassociatedwiththedensityofHimalayanmarmot(p<0.01).Conclusion:Climatechangewasassociatedwiththeriskofplague.ThisphenomenonisvaluableforHimalayanmarmotandplagueprevention.MorestudiesareneededtounderstandtheimpactofclimatechangeonHimalayanmarmotandplague.

简介：啮齿类动物是散布了瘟疫，和Spermophilusdauricus的主要主人动物(S。dauricus)是在诺思中国的最普通的啮齿类动物。在这研究，啮齿类动物密度调查从4月在瓷器吉林省被执行到2005年8月。我和semivariogram弄弯的Morans被用来调查采样数据的空间分发特征。我们发现空间自相关索引低、失败产生一条有意义的semivariogram曲线。在这种情况中，通常使用内插器，例如kriging，不对在学习区域上印射密度合适。然而，三明治模型，基于空间成层的异质，能被用于我们的数据。我们的结果证明土壤和土地使用的类型显著地影响了啮齿类动物密度的分发，并且这些变量的交互效果独自比每个变量的强壮得多。估计三明治的啮齿类动物密度地图证明那啮齿类动物密度在吉林省从东南增加了到西北。最后，用三明治模型的啮齿类动物密度调查的一个框架被介绍。

简介：原子磁性的时刻是一个重要物理变量并且为原子模型的紧测试用作一个有用工具。为过去的十年，功能的理论和它的延期被证明了在描述原子地面状态成功并且激动的covariant密度说性质。然而，一个长期的问题是它的失败预言磁性的时刻。这篇文章在covariant密度以内在对原子磁性的时刻的描述考察最近的进步功能的理论。特别地，磁性的时刻球形奇怪--有二倍地关上的壳核心加或减一个核子的A原子核并且使变形奇怪--一原子核。

简介：§1.IntroductionandMainResultLet(X,F)beaJBrXR'-valuedvector.AssumethatwhenX=xisgiven,thereexistsaconditionaldensityofYtobedenotedbyf(y[x),whichisaBorel-measurablefunctionof(x,y).Notethatwedonotassumetheexistenceofadensityfunctionof(X,F).Let(X-i,fi),—,(Xn,Fn)bei.i.d.samplesof(X,F).Ourpurposeistoestimatef(y\x)basedonthesesamples.Thisisaninterestingprobleminviewofeitherpuretheoryorpracticalapplications.MotivatedbytheideasuggestedinkernelandNNestimationsinthetheoryofnonparametricregressionanddensityestimates,thefirstauthorproposesthefollowingtwoclassesofestimatorsoff(y\x):

简介：Therelationshipbetweengainandcarrierdensityisanalysed.Inthequantumwell(QW)lasers,initially,thegainincreasesrapidlywiththecarrierdensityandthenstartstosaturate.ItcanbeseenthatQWlasershaveahigherdifferentialgainbecauseofthestep-likestatedensity,andthatthegainsaturatesathighercarrierdensitiesbecauseoftheconstantstatedensityofthelowestsubband.Itisshownthatsimpleogarithmicgain-carrierdensityismoreaccuratethanthetraditionallinearizedformforaQWlaser.