共查询到20条相似文献,搜索用时 15 毫秒
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Xiong Dasheng Du Dongyao Department of Mathematics Southwest China Normal University Chongqing Financial Section Sichuan Union University Chengdu 《西南师范大学学报(自然科学版)》1999,(5)
Theissueofoptimaleconomicgrowthistheproblemofoptimalratioinaccumulationandconsumption.Ifthepresentconsumptionistoohigh,theaccumulationwillbelowandthatwilleffecttherapidincreaseoffutureconsumption.Ontheotherhand,ifthepresentaccumulationistoohigh,thep… 相似文献
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Althoughthedesignofcomputingschemeinthenumericalweatherpredictionismainlytoimprovethespacialdifference,theresearchforimprovingthetimedifferenceschemehasseenapparentprogresses[1~5].Itisconfirmedthattheretrospectivetimeintegralschemeadoptedinaspectrummodel,whichutilizesmultitimehistoricaldata,improvestheaccuracyofthenumericalweatherprediction[6,7].Inthisarticle,weapplytheretrospectivetimeintegralschemetoasimpledifferencemodel,performnumericalexperimentsandpresentacomparisonanalysis.1 Principle… 相似文献
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A set of numerical tests was carried out to compare the retrospective time integral scheme in a self-memory model,whose dynamic kernel is the barotropical quasi-geostrophic model, with the ordinary centered difference scheme in the barotropical quasigeostrophic model. The Rossby-Haurwitz wave function was taken as the initial fields for both schemes. The results show that in comparison with the ordinary centered difference scheme, the retrospective time integral scheme reduces by 2 orders of magnitude the forecast error, and the forecast error increases very little with lengthening of the time-step. Therefore, the retrospective time integral scheme has advantages of improving the forecast accuracy, extending the predictable duration and reducing the computation amount. 相似文献
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Extending the effective medium approximation with the fractal theory for describing nanoparticle clusters and their radius distribution, a predictive model is proposed for the effective thermal conductivity of nanoparticle suspension, combined with the consideration of size effect and surface adsorption effect of nanoparticles.The predicted effective thermal conductivity of nanoparticle suspension is consistent with experimental data in the dilute limit. 相似文献
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《科学通报(英文版)》1995,40(18):1512-1512
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Development of the CAS-LIBB single-particlemicrobeam for localizedirradiation of living cells 总被引:3,自引:0,他引:3
《科学通报(英文版)》2004,49(17)
The use of microirradiation techniques in radiationbiology dates back to the work of Zirkle and his col-leagues in 1950’s[1,2]. However, biological effects of arandom single particle traversal in living materials re-mained highly unknown since they could not be simulatedby conventional broad-field radiation exposures. In recentyears, there has been a resurgence of interest in sin-gle-particle/single-cell microbeams[3—12]. The biologicalinterest in the single-particle microbeam stems from the… 相似文献
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A subfossil chironomid-total phosphorus inference model for lakes in the middle and lower reaches of the Yangtze River 总被引:1,自引:0,他引:1
ZHANG Enlou Alan Bedford Richard Jones SHEN Ji WANG Sumin TANG Hongqu 《科学通报(英文版)》2006,51(17):2125-2132
Quantitative environmental reconstruction using subfossil chironomid has attracted much attention in recent years[1]. Consisting of about 400 genera, chi- ronomids (Diptera: Chironomidae) are found in nearly all freshwater bodies[2]. They are holometabolo… 相似文献
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WANGXufei WANGXiaohua CHENLianyun HUZhiwen LIJun WUYu CHENBin HUSuhua ZHANGJun XUMingliang WULijun WANGShaohu FENGHuiyun ZHANFuru PENGShixiang HUChundong ZHANGShuqing CHENGJianjun SHIZhongtao YUANHang YUANHaitao YUZengliang 《科学通报(英文版)》2004,49(17):1806-1811
A single-particle microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering (LIBB), Chinese Academy of Sciences (CAS). The system was designed to deliver a defined numbers of hydrogen ions, produced by a van de Graaff accelerator, in an energy range of 2.0-3.0 MeV, into an area smaller than that of the nucleus of an individual living cell. The beam is collimated by a borosilicate glass capillary that forms the beam-line exit. An integrated computer program recognizes the cells and locates them one by one over the microbeam exit for irradiation. We present technical details of the CAS-LIBB microbeam facility, particularly on the collimator, hardware, control program, as well as cell irradiation protocols available. Various factors contributing to the targeting and positioning precision are discussed along with accuracy measurement results. 相似文献
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DINGWeiping HE Liqun ZHAO Gang SHU Zhiquan CHENG Shuxia & GAO Dayong . Department of Thermal Science & Energy Engineering University of Science & Technology of China Hefei China . Department of Mechanical Engineering University of Kentucky Lexington KY - USA Correspondence should be addressed to Gao Dayong 《科学通报(英文版)》2003,48(21)
Hemodialyzers have been applied to hemodialysiswidely. In order to get accurate mass transfer coefficient and clearance to determine treatment time, their masstransfer models have been studied deeply. The domesticstudy on hemodialyzers is later, focuses on experiment, and seldom refers to theoretical mechanism[1,2], but theoverseas research is more in-depth. Simple one-dimensional models have been used to simulate mass transfer in hemodialyzers by many re-searchers[3—7]. Their models assumed … 相似文献
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JIAO Nianzhi FENG Fuying WEI Bo 《科学通报(英文版)》2006,51(8):889-896
The sea is the cradle of photosynthesis on the Earth. Bio-utilization of light in the sea is usually thought to be carried out by light-harvesting pigments, such as normal chlorophyll, divinyl chlorophyll and bacterial chlorophyll, which exist correspondi… 相似文献
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LIU Xiao-Juan KANG Xu-Ping 《井冈山学院学报》2002,(3)
“ThereisnoregionintheU.S.thatcontainsasmuchbeauty,violence,passion,courageandfinally,tragedyastheAmericanSouth.Andinthetwentiethcentury,thereisnonovelistwhomorepowerfullyandeloquentlyrepresentsthisregioninhisfictionthanWilliamFaulkner.”(WanPeide,1986)FaulknerranksamongtheleadingAmericanauthorsofthetwentiethcentury.Hewasaregionalist,whospentmostofhislifeinasmall,particularareaoftheUnitedStates,writingaboutthescenesandpeopleheknewbest.BornintoadistinguishedMississippi… 相似文献
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Prospects for study of tectono-geochemistry 总被引:1,自引:2,他引:1
Focusing on fault tectono-geochemistry, the authors will illustrate four aspects of the fault tectono-geochemistry and its research prospects: (1) the major elements, trace elements and rare earth elements and their differentiation and dissipation sequence; (2)mineral veins, secondary inclusions, sync-deformation fluids and their micro-kinetic analyses; (3) pressure intensity, temperature grads,solution concentration and their coupled correlation system; (4) tectonic stress fields, rheologic physical fields, geochemical fields and digital modeling of parameters. The four aspects are unique in their own systems and related to one another. A unified explanation of spatial and temporal evolution can be obtained in combination with the geodynamics and tectonic chronology. 相似文献
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How to protect the database, the kernel resources of information warfare, is becoming more and more important since the rapid development of computer and communication technology. As an application-level firewall, database security proxy can successfully repulse attacks originated from outside the network, reduce to zerolevel damage from foreign DBMS products. We enhanced the capability of the COAST‘ s firewall reference model by adding a transmission unit modification function and an attribute value mapping function,describes the schematic and semantic layer reference model, and finally forms a reference model for DBMS security proxy which greatly helps in the design and implementation of database security proxies. This modeling process can clearly separate the system functionality into three layers, define the possible security functions for each layer, and estimate the computational cost for each layer. 相似文献
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LI HaoYuan CHEN Liang QIAO Juan DUAN Lian DONG GuiFang WANG LiDuo QIU Yong 《科学通报(英文版)》2013,58(1):79-83
Short range order model is commonly used to explain the charge transport property of disordered organic semiconductors.However,its validity is not yet studied.In this paper,the hole and electron mobilities of a bipolar material,N,N’-dicarbazolyl-1,4dimethene-benzene(DCB),were measured through time of flight method.The hole and electron mobilities of DCB based on the crystalline structure were calculated.In order to investigate the short range order model,the ratios of charge mobilities at zero electric field of holes to electrons were calculated.The results showed that this model cannot fully explain our case.The reason was discussed in detail,and a correction method was proposed.We showed that using the short range order model without preconditions to explain the charge transport property of amorphous materials may lead to deviations,which is often neglected in the past. 相似文献
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A DNA based model for addition computation 总被引:4,自引:0,他引:4
Much effort has been made to solve computing problems by using DNA-an organic simulating method, which in some cases is preferable to the current electronic computer. However, No one at present has proposed an effective and applicable method to solve addition problem with molecular algorithm due to the difficulty in solving the carry problem which can be easily solved by hardware of an electronic computer. In this article, we solved this problem by employing two kinds of DNA strings, one is called result and operation string while the other is named carrier. The result and operation string contains some carry information by its own and denotes the ultimate result while the carrier is just for carrying use. The significance of this algorithm is the original code, the fairly easy steps to follow and the feasibility under current molecular biological technology. 相似文献
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Numerical simulations are performed on the gas fluidization of the secondary agglomerates of SiO2 and SiC nanoparticles. An Eulerian two-fluid approach is used, which models the solids stress modulus with an empirical Jung-Gidaspow relationship and the drag force based on the secondary agglomerates. The results show the behaviour of particulate fluidisation of the secondary agglomerates of nanoparticles. The fluidised bed has a very high expansion ratio but without distinct bubbles. A three-zone distribution of time-averaged particle concentration is observed along the bed height. These are a dense zone in the lower part of the bed, a dilute zone at the top part, and a transitional zone lies in between. The radial distribution of particle concentration is found to be nearly homogeneous in both the dilute and transitional zones. The modelling results are compared with experimental results reported in the literature and reasonably good agreement has been achieved. 相似文献