共查询到19条相似文献,搜索用时 118 毫秒
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高永华 《石家庄师范专科学校学报》2001,3(2):39-41
针对双重Q^2重标度模型存在的问题,提出了改进的双重Q^2重标度模型,利用该模型所得到的束缚核子内部分子分布函数,对核Drell-Yan过程给出了满意的解释。 相似文献
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高永华 《石家庄师范专科学校学报》2001,3(4):11-13
给出了推广x重新标度模型的重标度参数公式,并利用该公式给出的铅核的重标度参数值,计算了铅核与氘核的平均结构函数之比,结果表明,理论计算与实验数据符合较好,从而对重标度参数公式进行了检验。 相似文献
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给出了推广x重新标度模型的重标度参数公式,并利用该公式给出的铅核的重标度参数值,计算了铅核与氘核的平均结构函数之比,结果表明,理论计算与实验数据符合较好,从而对重标度参数公式进行了检验. 相似文献
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记H为复可分无限维Hilbert空间,H上的有界线性算子F若满足F2=F,则称F为幂等算子,P(N(F)),PF分别为幂等算子F的核空间N(F),值域R(F)上正交投影.借助算子分块技巧,给出PFP(N(F))范数的表达式,进一步研究了PQP(N(Q))及PQ-P(N(Q))范数的最大值与最小值,其中Q是满足R(Q)=R(F)的H上的幂等算子. 相似文献
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提出了一个能构建小世界网络和无标度网络的演化模型,这演化模型保持节点规模和边数量不变,引入边非线性择优重连方法.数值模拟表明:当边重连概率比较小时,能生成小世界网络,而当重连概率等于1时,能生成无标度网络. 相似文献
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结晶凝固形核时,晶核的自由能刚开始随着半径增加而增大,到达某临界值后自由能开始降低.形核是一个热激活过程,需要克服一个形核功,通常认为,临界晶核的数目正比于激活项exp(—ΔG*/kT),临界晶核接收一个扩散原子的概率正比于扩散项exp(—Q/kT),形核率正比于exp(—ΔG*/kT)exp(—Q/kT),在某一个过... 相似文献
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介绍一种基于FPGA的LCD液晶显示驱动IP核的设计。该设计采用VHDL硬件描述语言,以Altera公司的Cyclone II系列FPGA—EP2C8Q208C8芯片为载体,实现了对液晶显示的控制。结果表明,该设计是实现12864液晶显示的一种行之有效的方法,且控制灵活,可靠性高。 相似文献
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本文将从关联理论中的明示-推理模式出发,针对译者与原文作者以及译者与译文读者之间的交际失误这两大案例,分别从语言和文化两个方面对钱钟书先生的《围城》的英译本进行分析,着重研究明示-推理模式对翻译实践的指导性。 相似文献
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Andrew C. Dwyer 《Journal of Educational Measurement》2016,53(1):3-22
This study examines the effectiveness of three approaches for maintaining equivalent performance standards across test forms with small samples: (1) common‐item equating, (2) resetting the standard, and (3) rescaling the standard. Rescaling the standard (i.e., applying common‐item equating methodology to standard setting ratings to account for systematic differences between standard setting panels) has received almost no attention in the literature. Identity equating was also examined to provide context. Data from a standard setting form of a large national certification test (N examinees = 4,397; N panelists = 13) were split into content‐equivalent subforms with common items, and resampling methodology was used to investigate the error introduced by each approach. Common‐item equating (circle‐arc and nominal weights mean) was evaluated at samples of size 10, 25, 50, and 100. The standard setting approaches (resetting and rescaling the standard) were evaluated by resampling (N = 8) and by simulating panelists (N = 8, 13, and 20). Results were inconclusive regarding the relative effectiveness of resetting and rescaling the standard. Small‐sample equating, however, consistently produced new form cut scores that were less biased and less prone to random error than new form cut scores based on resetting or rescaling the standard. 相似文献
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In this study, the authors investigated incorporating adjusted model fit information into the root mean square error of approximation (RMSEA) fit index. Through Monte Carlo simulation, the usefulness of this adjusted index was evaluated for assessing model adequacy in structural equation modeling when the multivariate normality assumption underlying maximum likelihood estimation is violated. Adjustment to the RMSEA was considered in 2 forms: a rescaling adjustment via the Satorra-Bentler rescaled goodness-of-fit statistic and a bootstrap adjustment via the Bollen and Stine adjusted model p value. Both properly specified and misspecifed models were examined. The adjusted RMSEA was evaluated in terms of the average index value across study conditions and with respect to model rejection rates under tests of exact fit, close fit, and not-close fit. 相似文献
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本文在考虑随机投资收益率的基础上,对双二项风险模型进行研究,得到了最终破产概率满足的Lundberg不等式以及一般公式. 相似文献
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乐茂华 《商丘师范学院学报》2005,21(5):30-31
对于正整数m,设Fm=2^2^m+1是第m个Femat数,Q(Fm)是Fm的无平方因子部分.本文证明了:Q(Fm)〉2^4m-6/m^2. 相似文献
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杨军 《商丘师范学院学报》2011,27(9):20-22
主要研究了如下近似Hamilton系统{x=y y=-x3+εQ(x,y)的极限环情况,其中Q(x,y)=∑lj=0 ajxj|y|2m.通过分析其一阶Melnikov函数,证明了当l=2n-2或2n-1时其存在n个极限环. 相似文献
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1Introduction AGalton Watsonbranchingprocessinrandom environments[13]isageneralizationofstandardGalton Watsonbranchingprocesses.Itwasfirstformulatedby SmithandWilknson[1]inthespecificcasewheretheen vironmentalprocessisi.i.d.randomvariables.The structureof… 相似文献
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推广了Kou等人提出的双指数跳扩散模型,建立了更具解释灵活性的广义双指数跳扩散模型,应用鞅方法,测度变换、线性变换等方法推导出了广义双指数跳扩散模型下的欧式期权定价公式. 相似文献