简介：Ithaslongbeenrecognizedthattherotationofsingleparticlesplaysaveryimportantroleinsimulationsofgranularflowusingthediscreteelementmethod(DEM).ManyresearchershavealsopointedoutthattheeffectofrollingresistanceatthecontactpointsshouldbetakenintoaccountinDEMsimulations.However,evenforthesimplestcaseinvolvingtwo-dimensionalcircularparticles,thereisnoagreementonthebestwaytodefinerollingandsliding,anddifferentdefinitionsandcalculationsofrollingandslidinghavebeenproposed.Ithasevenbeensuggestedthatauniquerollingandslidingdefinitionisnotpossible.Inthispaperweassessresultsfrompreviousstudiesonrollingandslidingindiscreteelementmodelsandfindthatsomeresearchershaveoverlookedtheeffectofparticlesofdifferentsizes.Afterconsideringtheparticleradiusinthederivationofrollingvelocity,allresultsreachthesameoutcome:auniquesolution.Wealsopresentaclearandsimplederivationandvalidateourresultusingcasesofrolling.Suchadecompositionofrelativemotionisobjective,orindependentofthereferenceframeinwhichtherelativemotionismeasured.

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简介：这份报纸为随机的波浪方程和时空白人噪音驾驶的随机的有弹性的方程涉及有限元素方法。为简洁，我们重写随机的夸张方程的二种类型进一种统一形式。我们由discretizing把随机的夸张方程变换成一个调整方程白噪音然后为调整方程考虑完整分离的有限元素方法。我们由由使用确定的方程的错误估计使用“格林的方法”和有限元素近似错误导出当模特儿的错误。一些数字例子被举验证理论结果。[从作者抽象]

简介：我们为经由公共密钥的密码学在二个合法聚会(鲍勃和艾莉斯)之间分享的信息建议一个协议。特别地，我们由采用分离算法在下面专业化协议现代派那经由光子旋转印射整数到量状态。基于这个算法，我们发现协议在攻击的各种各样的班下面是安全的。特殊，欠到算法，在公共密钥的量和相应密文包含的古典隐私的安全被保证。并且协议由设计特别检查对扮演攻击和活跃wiretapping攻击是柔韧的处理，这样协议是有效的。

简介：Wefirstdesignadiscretehyperchaoticsystemviapiecewiselinearstatefeedback.Thestatesoftheclosedloopsystemarelocallyexpandingintwodirectionsbutabsolutelyboundedonthewhole,whichimplieshyperchaos.Then,weusethreesuchlikehyperchaotiesystemswithdifferentfeedbackgainmatricestodesignapseudo-randomsequencegenerator(PRSG).Throughathresholdfunction,threesub-sequencesgeneratedfromtheoutputofpiecewiselinearfunctionsarechangedinto0-1sequences.Then,followedbyXORoperation,anunpredictablepseudo-randomsequence(PRS)isultimatelyobtained.TheanalysisandsimulationresultsindicatethatthePRS,generatedwithhyperchaoticsystems,hasdesirablestatisticalfeatures.

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简介：linear-springdashpot(迷幻药)和接触建模的非线性的Hertzian-springdashpot(HSD)通常在小粒的系统的分离元素方法(DEM)模拟为接触力量的计算被使用。尽管有这些模型，为象僵硬那样的模仿的粒子的接触参数的合适的值的决心，抑制系数，归还的系数，和模拟的流行，预定步，不完全是明显的。在这个工作，在这些之间的关系为一座公寓上的影响基于的一个粒子被检验的一个模型系统联系参数。建议在DEM模拟为使用有关这些接触参数的决心被做。

简介：在这篇论文，二维的弄歪的分离Fourier变换(2-DWDFT)基于1-DWDFT的概念被开发。一个准确计算算法与特殊结构基于矩阵factorizing为2-DWDFT被开发。一个快算法然后被建议极大地减少反的2-DWDFT的计算复杂性。最后，数字例子被给显示出建议途径的效率。

简介：Inthispaperweprovideasufficientandnecessaryconditionfortheeigenvalueandeigenvectorofageneralreduciblematrixinadiscrete-eventsystemdescribedbythe“max”algebra,analysethesteadyperiodicalperformanceofthesystem,andobtainananalyticsolutionofthedynamicequation.Weproposetheconceptionof“order-d-(?)-block-periodicalmatrix”andobtainitssufficientandnecessaryconditionandprovideanalgorithmof(?)matrix.

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简介：AbstractBackground:As COVID-19 makes its way around the globe, each nation must decide when and how to respond. Yet many knowledge gaps persist, and many countries lack the capacity to develop complex models to assess risk and response. This paper aimed to meet this need by developing a model that uses case reporting data as input and provides a four-tiered risk assessment output.Methods:We used publicly available, country/territory level case reporting data to determine median seeding number, mean seeding time (ST), and several measures of mean doubling time (DT) for COVID-19. We then structured our model as a coordinate plane with ST on the x-axis, DT on the y-axis, and mean ST and mean DT dividing the plane into four quadrants, each assigned a risk level. Sensitivity analysis was performed and countries/territories early in their outbreaks were assessed for risk.Results:Our main finding was that among 45 countries/territories evaluated, 87% were at high risk for their outbreaks entering a rapid growth phase epidemic. We furthermore found that the model was sensitive to changes in DT, and that these changes were consistent with what is officially known of cases reported and control strategies implemented in those countries.Conclusions:Our main finding is that the ST/DT Model can be used to produce meaningful assessments of the risk of escalation in country/territory-level COVID-19 epidemics using only case reporting data. Our model can help support timely, decisive action at the national level as leaders and other decision makers face of the serious public health threat that is COVID-19.

简介：在这份报纸，一个频率领域决定反馈均衡器为单身的搬运人传播被建议，时间颠倒时空块(TR-STBC)编码。斜决定反馈均衡器矩阵能从频率领域隧道反应是计算的，这被显示出。在完美的反馈假设下面，建议均衡器能接近匹配的过滤器界限(MFB)。与存在时间领域决定反馈均衡器相比，建议均衡器与一样的均等复杂性展出更好的性能。

简介：【摘要】对于小学生来说,只有将语法放入语境中教,他们对语法知识的理解才会更加透彻,也更容易通过相关实践活动将这些语法知识转化为语言运用能力。本文笔者结合译林新版《英语》五下Unit 8 Birthday中Grammar time和Fun time的教学,探讨教师如何围绕语境开展语法教学。立足单元话题,搭建语法支架。用单元话题开展核心词汇的发散式学习。词汇是语言学习的基石,词汇教学,教师应做到词不离句,句不离篇。所以,在语法板块中教词汇,教师应该通过一个具体的语境将语法进行教学。

简介：【摘要】对于小学生来说,只有将语法放入语境中教,他们对语法知识的理解才会更加透彻,也更容易通过相关实践活动将这些语法知识转化为语言运用能力。本文笔者结合译林新版《英语》五下Unit 8 Birthday中Grammar time和Fun time的教学,探讨教师如何围绕语境开展语法教学。立足单元话题,搭建语法支架。用单元话题开展核心词汇的发散式学习。词汇是语言学习的基石,词汇教学,教师应做到词不离句,句不离篇。所以,在语法板块中教词汇,教师应该通过一个具体的语境将语法进行教学。

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简介：爱因斯坦——诺贝尔物理学奖获得者，荣获了很高的荣誉，但因战争也经历了流离失所的日子。他是一位二十世纪最伟大的科学家之一。

简介：简介TimeTrackerStarterKit使开发人员能够轻松地创建项目跟踪应用程序，帮助用户跟踪分配给特定项目的时间。TimeTrackerStarterKit的思想是提供一个框架，可以使用它快速组织一个实现项目和时间管理系统的实用Web站点。这个StarterKit提供了一系列页而，可以很容易地管理分配给多个项目的时间。它的启始页面包括一个主页，可以记录各个用户分配给特定项日的时间，而其他贝阿允许查看项目、分配给项目的资源以及基于项目或资源的报告。

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简介：Livercelltransplantationpresentsclinicalbenefitinpatientswithinbornerrorsofmetabolismasanalternative,oratleastasabridge,toorthotopiclivertransplantation.Thesuccessofsuchatherapeuticapproachremainslimitedbythequalityofthetransplantedcells.Cryopreservationremainsthebestoptionforlong-termstorageofhepatocytes,providingapermanentandsufficientcellsupply.However,isolatedadulthepatocytesarepoorlyresistanttosuchaprocess,withasignificantalterationboth...