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61.
通过选择部分高校的体育教育专业的教师和人才培养方案(教学计划)、部分中小学体育教师作为研究对象,运用文献资料法、问卷调查法、数理统计法等研究方法,对基础教育改革下的我国高校体育教育专业人才培养现状进行深入调查和客观分析,找出当前我国高校体育教育专业人才培养目标定位、培养内容,以及体育教育专业学生的教育思想、创新能力、综合素质不能很好地适应基础教育体育与健康课程改革的要求等现实问题,对高校体育专业人才培养的发展定位、目标体系、具体内容提出了相应的对策和建议  相似文献   
62.
为了提高智能电网中家域网的传输控制协议(TCP)性能,提出一种自适应速率控制方法。家域网采用电力线通信(PLC)和无线局域网(WLAN)技术,具有异构特点。该控制方法利用WLAN的通信机制提高PLC的链路利用率,采用启发式动态规划,通过神经网络训练估计瓶颈链路的容量,根据应用的长期服务质量调整TCP数据包的发送速率。仿真结果表明,该方法可以有效滤除PLC信道中冲击噪声的负面影响,其性能优于现有TCP的拥塞控制。  相似文献   
63.
The Chinese alligator, Alligator sinensis, is a critically endangered species. A conservation project of gene resources for an endangered species first involves the preservation of organs, tissues, gametes, genomic DNA libraries and cell lines. The present study is the first to establish and cryopreserve cell lines of liver, heart and muscle tissues from the Chinese alligator. The study revealed that there was a large discrepancy in cell migration time in primary cultures among liver (11-12 d), heart (13-14 d) and muscle (17-18 d) tissue pieces. The differences in time in primary cell culture suggested that it was relatively easy to build visceral-derived cell lines for reptiles. Biological analysis showed that the population doubling time for thawed cells was approxi- mately 36 h. Karyotyping revealed that the frequency of Chinese alligator cells showing chromosome number as 2n=32 was 88.6%-93.4%. Chinese alligator cell lines established here provide a vital resource for research and are likely to be useful for protection of this rare and critically endangered species. Furthermore, the establishment of these methods may supply technical and theoretical support for preserving genetic resources at the cellular level for other reptile species.  相似文献   
64.
Experimental study on the explosive boiling in saturated liquid nitrogen   总被引:1,自引:0,他引:1  
Nowadays,thedevelopmentandapplicationofsuperconductionisbecomingmoreandmoreimpor tantinmanyareas .Duringtheworkingprocessofsu perconductor,somefactors ,forinstance ,deforma tion ,friction ,andmagneticvortex ,canresultinin stantaneousandrandomheatimpulsion ,andmakeitover heatedtothecriticaltemperatureanddeviatefromthenormaloperationcondition .Undersomeex tremeconditions ,thesuperconductorcannotgobacktothenormalstateevenifremovingthetransientheat load ,thusverysevereandunexpectableconse quencema…  相似文献   
65.
Thetherapyofnerveinjuryandneurode generativediseasessuchasAlzheimer’sdiseaseandParkinson’sdiseaseisadifficultprojectforscientiststosurmount.Manydrugsandtherapeuticapproacheshavebeenusedtotreatthesediseases ,buttheresultisunsatisfactory[1] .Inrecent years ,neurotrophinsincludingnervegrowthfactor (NGF) ,neurotrophin3(NT3) ,neurotrophin 4 / 5 (NT4 / 5 )andbrain de rivedneurotrophicfactor (BDNF)werestudiedex tensivelyandfoundtoaffectthesurvival,growth ,and/ordifferentiationofneuronsandsever…  相似文献   
66.
Thenotionofpackingmeasure ,introducedinRefs.[1— 3],hasbeenusedincomparisonwithHausdorffmeasuretostudytheregularityandrectifi abilityofsetsintheplane[4 ] .TheHausdorffmeasureisdefinedusingeconomicalcoversofaset,whilethepackingmeasureisdefinedviapackingwithdisjointballscenteredinthegivenset (formoredetailsseeRefs .[5— 7]) .Asasymmetryofthepackingmea sure ,theHausdorffcenteredmeasure ,definedbythecoverswithballscenteredinthegivenset,wasintro ducedinRef .[4 ].RaymondandTricot[8] verifiedthatt…  相似文献   
67.
依据图的边独立指数概念,探讨了单圈连通图的边独立指数的相关性质,得到了单圈连通图边独立指数的上、下界,并给出了单圈连通图边独立指数达到上、下界的极图  相似文献   
68.
Polyoxometalates (POMs) form a large class ofmetal oxide cluster type compounds. Their wealthytopology, physical and chemical properties have at tracted increasing interests. In this paper, based onour group’s research, we review the latest progress inthe synthetic chemistry and catalysis of POMs and in troduce some POMs with novel structure and theirderivatives that emerged in 2002—2004. Most of thecited references come from those published in 2003.Due to POMs’superio…  相似文献   
69.
IntroductionThe behavior of bubbles,especially theirformation,interaction and coalescence,are of keyimportance in such fields as gas- liquid contact,gas- liquid separation,bubble absorption,bubblecolumns,fermentation,cavitations,etc. Theinduced fluid moti…  相似文献   
70.
ComparativeAnalysisandFuzzySelectionofInformationSystemDevelopmentApproach⒇CHENXiaohong*LIUMai*YASUHIKOTakahara***ColegeofBus...  相似文献   
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