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The cross sections of Ni(n,x)~(58(m g))Co,Ni(n,x)~(60m)Co,Ni(n,x)~(61)Co and Ni(n,x)~(62m)Co reactions induced by neutrons around 14 MeV were measured in this work and calculated by a previously developed formula in this work.The neutron flux was determined using the monitor reaction ~(27)Al(n,α)~(24)Na and the neutron energies were measured with the method of cross-section ratios for ~(90)Zr(n,2n)~(89)Zr to ~(93)Nb(n,2n)~(92m)Nb reactions. 相似文献
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本文提出了一种对季节性数据建立数学模型的新方法──横断面方法.其思想是,把一个季节性时间序列划分成为数相当于一个季节周期长度的若干个子序列,在这些子序列中已完全消除了季节性因素,然后对这些子序列分别建立形式各异的数学模型,最后再把这些子序列的数学模型综合起来就得到了对原始序列的数学模型. 相似文献
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E,E-1,4-Bis(4'-N,N-diphenylaminostyryl)-2,5-dimethoxybenzene (DPAMOB) has been synthesized by a simple and effective solid phase Wittig reaction and characterized by 1^H NMR spectra and elemental analysis, Linear absorption, single-photon induced fluorescence and two-photon induced fluorescence spectra were experimentally studied. The new dye has a large two-photon absorption (TPA) cross-section of σr= 1007,2 GM [1 GM= 1 × 10^-50 cm^4·s/(photon molecule)] at 800 nm measured by the two-photon induced fluorescence method. The experimental results confirm that DPAMOB is a good TPA chromophore and can successfully initiate two-photon photopolymerization of ethoxylated trimethylolpropane triacrylate esters (SR454). Finally, a microstructure has been fabricated by use of DPAMOB as initiator. 相似文献
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Based on calculating the contributions of the littlest Higgs model with T-parity (called LHT model) to the anomalous top coupling tqγ (q = u or c), we consider single top production via the t-channel partonic process eq→et in ep collisions. Our numerical results show that the production cross section in the LHT model can be significantly enhanced relative to that in the standard model (SM). 相似文献
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J.C.SONG 《应用数学和力学(英文版)》2011,32(10):1333-1338
The spatial decay of solutions to initial-boundary value problems for a semilinear parabolic equation in a semi-infinite cylinder
of variable cross-section subject to zero condition on the lateral boundaries is investigated. A second-order differential
inequality that shows the spatial decay O(exp(−z
2/(4(t+t
0)))) for an L
2p
cross-sectional measure of the solution is obtained. A first-order differential inequality leading to growth or decay is
also derived. In the case of growth, an upper bound for blow-up in space is obtained, while in the case of decay an upper
bound for the total energy in terms of data is obtained. 相似文献
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YAN Yu-Liang SUN Xiao-Jun ZHANG Yue ZHANG Jing-Shang 《理论物理通讯》2007,47(1):102-106
A new light nuclear reaction model has been developed and the double-differential measurements of lp shell nuclei have been analyzed successfully. Now, the application of this model is expanded to 19F of the 2s-ld shell nucleus. The double-differential cross section of total outgoing neutron for n +^19F reactions at En=14.2 MeV has been calculated and analyzed, which agrees fairly well with the experimental measurements. In this paper, the contributions from different reaction channels to the double-differential cross sections have been analyzed in detail. The calculations indicate that this light nudear reaction model is also able to be used for the 2s-ld shell nucleus so long as the related level scheme couM be provided sufficiently. 相似文献
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为了快速准确进行西洋参和人参的品种鉴别,从主根横断面入手,采集其横断面的近红外光谱,分别从物理结构因素和化学因素方面对光谱进行了分析,选定特定波段进行物理因素主导建模、化学因素主导建模、理化因素综合建模,并对三种建模结果进行比较分析,发现三种模型判别率都在96%以上,都能很好的满足批量原材料快速检测的需求。物理因素模型运算简单,但判别率相对低。化学因素判别率较高,但运算量大。理化因素综合模型判别率最高为100%,无需预处理,运算量小,效果最理想,该结果说明近红外定性判别中物理结构因素有时也发挥重要作用。横断面鉴别法准确、便捷,可实际应用于企业原料药材的质量控制,实现对原料药材的快速筛查。 相似文献
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题目 水渠横断面为等腰梯形,如图1,梯形面积为定值s,渠深为h,为了使渠道的渗水量达到最小(即水与水渠的接触面最少),应使梯形两腰及下底边长和最小,问此时腰与下底边夹角θ应为多大? 相似文献
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