排序方式: 共有37条查询结果,搜索用时 0 毫秒
11.
本文用塔姆-唐可夫近似解K+介子和核子的弹性散射问题,得到了K介子实验室动能400Mev以下的相移截面和能量的关系,并和实验及前人的理论结果作了比较。计算中较严格考虑了核子反冲效应,指出了在考虑了反冲效应后能使理论曲线在高能端更与实验曲线接近。同时就Λ-K和∑-K的各种可能的宇称情况进行了分析,排斥了相对宇称皆正的可能,并指出Λ-K和∑-K的相对宇称选取不同的符号和二者皆取负号一样,能符合K+-p散射实验,但在分析K+-n散射时仍遇到困难。 相似文献
12.
13.
本文提出了反常作用的μ荷观点,μ荷不仅是一种反映μ-e禁戒性的量子数,而且是反常作用的承担者。在此观点下,讨论了轻子结构和μ-e质量差,得到了关于轻子结构的一些普遍定理。例如,证明了电子的反常作用和电磁作用形状因子相同等。在讨论轻子结构的基础上,得到了将μ-e质量差和轻子的电磁结构相联系的公式,证明了主要由于电磁作用干涉产生的μ荷-μ矩作用是反常作用自能的主要部分,它是负值,故是电子参与反常作用。利用电子的电磁结构数据能合理地解释μ-e质量差,而后者也提供了有关电子电磁结构的进一步知识。 相似文献
14.
FENG XI-ZHANG ZHAO ZHEN-LAN GUO YING-HUAN LO SHI-HUA XU YUAN-BIAO YANG RUI-YING HUANG ZHONG-XIANG JIANG YONG 《中国物理C(英文版)》1982,6(5):642-647
The present paper examines theoretically the way of reducing tha errors introducedby the inaccuracy of the decay constant and measuring statistics in the determinationof the number of the radioactive atoms. It was discovered that the "front-back sym-metrical measurements with life-time as center" (FBSLC) may fulfil this reguirement.Even if the error of the decay constant reaches ±10%, the error introdnced by theinaccuracy of decay constant of the number of the radioactive atoms at zero time cal-culated from the radioactivities measured at zero time and two life-times by takingaverage will still be smaller than 0.1%. Experimental data of 99mTc radioactive decaywithin measuring statistics verified the above theoretical prediction. Therefore, by FBSLC with measuring time as early as possible, it is possible toreduce the errors introduced by inaccuracy of the decay constant and measuring sta-tistics, so that the results of the absolute measurements may be more accurate. 相似文献
15.
16.
A general discussion of the behavior of the shallow circular arch is presented. It is shown that, irrespective of specific loading or boundary conditions, it is possible to arrive at general conclusions regarding buckling, postbuckling, and imperfection sensitivity. General methods of analysis are established which lead to the determination of points of bifurcation and of postbuckling paths under symmetric loads. Modifications accounting for antisymmetric load components are introduced, with special emphasis on their asymptotic and limit load effect. A typical numerical example is carried through in detail. The solution is “exact” in the sense of shallow arch theory. Its asymptotic behavior conforms to the asymptotic theory of Koiter. 相似文献
17.
利用SEM—EDS分析了稀土氧化物在熟料中的分布并结合熟料的岩相分析初步探讨了稀土对水泥熟料烧成的矿化作用机理。研究结果表明,稀土元素La和Y在熟料煅烧过程中更多地分布在硅酸盐相中,同时增加了溶剂型氧化物(Al2O3、Fe2O3)在A矿中的固溶量;稀土离子的掺杂引起微观介质应力场发生畸变,增加结构中的空位缺陷,降低扩散活化能,从而提高质点的扩散速度,促进了C3S矿物的形成。 相似文献
18.
Resonance Raman studies of Ni2TIED3+ (TIED = tetraiminoethylenedimacrocycle) reveal that many modes couple to the intense electronic transition centered at 725 nm, a feature that is nominally similar to the intense delocalized intervalence absorption bands observed in the same region for Fe2(TIED)L4(5+) and Ru2(TIED)L4(5+) (L is any of several axial ligands). Time-dependent spectral modeling of the Raman and absorption spectra for the nickel compound was undertaken to understand the electronic transition. We were unable to model the Raman and absorption spectra successfully with a single electronic transition, suggesting that the absorption band is made up of two overlapping transitions. Semiempirical electronic structure calculations corroborate the suggestion. Additionally, these calculations indicate that the transitions are in fact ligand-localized transitions, with little metal involvement and no charge-transfer character. Furthermore, the ground-state electronic structure is best described as an identical pair of NiII centers bridged by a radical anion rather than a three-site mixed-valence assembly. Previous EPR studies (McAuley and Xu, Inorg. Chem. 1992, 31, 5549) had indicated primarily ligand character for the radical. The assignments are consistent with the resonance Raman results where the dominant modes coupled to the transitions are assigned as totally symmetric bridge vibrations. 相似文献
19.
20.
利用Katayama在一种Si断裂强度; 弯曲试验; 加载因子; Weibull模量 fracture strength, bending test, load factor, Weibull modulus 2002年6月25日 2003-12-10 利用Katayama在一种Si断裂强度; 弯曲试验; 加载因子; Weibull模量 fracture strength, bending test, load factor, Weibull modulus 2002年6月25日 2003-12-10 利用Katayama在一种Si3N4陶瓷得到的实验数据,考察了一条关联陶瓷材料三点及四点弯曲断裂强度的式子,其准确度较好,简要地导出了一般教材上较少提及其推导的四点弯曲加载因子。 相似文献