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While the standard model is the most successful theory to describe all the interactions and constituents of elementary particle physics,it has been constantly scrutinized for over four decades.Weak decays of charm quarks can be used to measure the coupling strength between quarks in different families and serve as an ideal probe for CP violation.As the lowest charm-strange baryons with three different flavors,Ξ;baryons(composed of csu or csd)have been extensively studied in experiments.In this study,we use state-of-the-art lattice QCD techniques to generate 2+1 clover fermion ensembles with two lattice spacings,a=(0.108,0.080 fm).Then,we present the first ab-initio lattice QCD calculation of the Ξ;→Ξ form factors.Our theoretical results for the Ξc→Ξl;v;decay widths are consistent with and approximately two times more precise than the latest measurements by the ALICE and Belle collaborations.Based on the latest experimental measurements,we independently obtain the quark-mixing matrix element |V;|,which is in good agreement with results from other theoretical approaches. 相似文献
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大豆二羟异黄酮及三羟异黄酮的高效液相色谱分析 总被引:5,自引:0,他引:5
1mol/L盐酸水解大豆及豆制品,乙腈提取,高效液相色谱分析了二羟、三羟异黄酮的含量。以甲醇-2mmol/L乙酸铵(体积比55:45,乙酸铵溶液用乙酸调pH至4.380)为流动相,Hypersil BDS C18色谱分析柱,柱温25℃,260nm紫外检测波长进行分析。二羟、三羟异黄酮的1-500μmol/L的范围内,与峰面积有很好的线性关系 (r=0.9999)。它们的检出限为5ng(S/N=3),平均回收率94.46%以上,6次进样的相对标准差(RSD)小于4%。该法灵敏、重复性好、结果准确、分析迅速。检测大豆及豆制品中异黄酮的含量,得到满意的结果。 相似文献
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CountablyCompactPropertyofG(H∞)SunWei(孙玮)(DepartmentofMathematics,SichuanUnionUniversity,Chengdu,610064andInstituteofAppliedM... 相似文献
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以甲烷/空气混合物为研究对象,开展了连通容器气体泄爆影响因素的实验研究。结果表明:连通容器泄爆片泄爆时,随着破膜压力和量纲一泄压比的减小,大、小球容器的最大泄爆压力均增大;在等量纲一泄压比条件下,随着连接管道长度的增加,传爆容器的最大泄爆压力增大。连通容器无膜泄爆时,大球点火条件下,无论管长如何,起爆容器和传爆容器均比单个容器最大泄爆压力大。小球点火条件下,当管道长度为0.45 m时,起爆容器和传爆容器的最大泄爆压力均小于单个容器。连通容器无膜泄爆且量纲一泄压比相同时,当管道长度为0.45 m时,大、小容器内的最大泄爆压力基本相等;当管道长度为2.45 m时,大容器点火时,传爆容器最大爆炸压力大于起爆容器,但小容器点火时,起爆容器最大泄爆压力大于传爆容器;当管道长度为4.45和6.45 m时,传爆容器最大泄爆压力均大于起爆容器。 相似文献
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Theoretical Analysis of Ionic Autoionization Spectra of Lanthanum in the Energy Region of 90650—915—00cm^—1 下载免费PDF全文
Eigenquantum defects μα and transformation matrix Uiα of La are calculated from the first principles byrelativistic multichannel theory, and dipole matrix elements Dα are obtained by fitting the experimental spectra.With these parameters, ionic autoionization spectra of lanthanum via an intermediatestate (Xe)5d6d^-1 P1 of La . in the energy region of 90650-91500 cm^-1 are calculated within the framework of multichannel auantum defecttheory. Our calculated spectra are in general agreement with the experimental data. 相似文献
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兔膝关节炎模型的关节软骨及软骨下骨 ,经盐酸水解 ,纤维素CF11分离吡啶诺林 (Pyr) ,高效液相色谱测定其含量 ;采用 μBondapakC18 柱 (10μm,3.9mm×300mm) ,以V 乙腈∶V 水[0.5 %(φ)七氟正丁酸]=25∶75为流动相,荧光检测器在λem 和λex 分别为390nm和297nm的条件下测定Pyr;在0.250~6.00μmol/L的范围内 ,Pyr含量与峰面积有良好的线性关系 ,r=0.9996 ,加标平均回收率是98 % ,相对标准差(n=6)是3.3 % ;样品测定结果显示 ,8周内 ,关节软骨中Pyr含量逐渐下降 ,软骨下骨中Pyr含量在早期下降 ,随后逐渐升高 ;骨胶原Pyr含量的变化是造成尿液Pyr升高的原因。 相似文献
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2-(4-取代-苯基)-3-异噻唑啉酮抗菌活性的定量构效关系研究 总被引:1,自引:0,他引:1
用密度泛函理论和逐步回归分析方法对22种新合成的2-(4-取代-苯基)-3-异噻唑啉酮化合物进行了结构与抗菌活性研究. 通过对平衡几何构型、前线轨道组成和Mulliken电荷分布的分析得出: S(1), N(2)原子是该类化合物的主要活性部位, 且5位氯取代的化合物抗菌活性较好. 通过回归分析, 筛选了影响抗菌活性的主要因素, 建立了定量构效关系方程. 结果表明, 硫原子的亲核前线电子密度、3D-Balaban指数、S(1)—N(2) Wiberg键级和Schultz分子价拓扑指数是影响异噻唑啉酮类化合物抗大肠杆菌活性的主要因素, 所得模型对化合物抗菌活性有较好的预报能力. 相似文献