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排序方式: 共有4494条查询结果,搜索用时 15 毫秒
941.
Bai Jingzhi Bian Jianguo Chai Zhengwei Chen HongfangChen Jiangchuan Chen Shaomin Chen Yaqing Chen YuanboCheng Baosen Cheng Baosen cui Xiangzong Ding Huiliang Du Zhizhen Fan XiaolingFang Jian Gao Cuishan Gao Meili Gao Shuqi Gu Jianhui Gu ShudiGu. Wei 《中国物理 C》1997,(5)
分析J/ψ衰变终态为三个光子的衰变道,测量得到了衰变道J/ψ→γπ0和J/ψ→γη’的分支比分别为Br(J/ψ→γπ0)=(4.6±1.1)×10-5和Br(J/ψ→ッη')=(4.12±0.82)×10-3;相对分支比F(J/ψ→γη’)/F(J/ψ→γη)=4.79±0.85,在实验误差范围内与两个理论模型的预言都能一致。 相似文献
942.
Molecules in the source region of a time of flight mass spectrometer are ionized by ultraviolet laser radiation. Under certain conditions mass spectra consisting of a remarkably periodic set of ion peaks are generated. It is demonstrated that these result from spatially periodic ionization within the mass spectrometer which is a consequence of the development of standing electromagnetic waves. 相似文献
943.
In this paper, based on the Naghdi shell model, we analyze the uniform convergence of mixed finite element methods for cylindrical
shell problems using macroelement techniques. We show that Taylor–Hood elements p
2-P
1 and P
1
iso P
2 are locking free elements for the model problems. Optimal error estimates are presented with these elements.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
944.
The characteristics of supercontinuum produced by high-intensity femtosecond pulses were investigated under different interaction
lengths, various pump intensities, different pump wavelengths at the fundamental 800 nm and its second-harmonic 400 nm. High
transfer-efficiency supercontinuum with flat-top in liquid media was produced. As the main nonlinear mechanisms, the effects
of self-phase modulation (SPM) and four-photon parametric emission were also investigated.
Project supported by Hong Kong Research Grant Council Project HKUST 633/94P, the China National Climbing Plan, and the Laboratory
of Optoelectronics and Information Engineering, the State Education Commission. 相似文献
945.
946.
The effect of friction in ferrules on compression tuning characteristics of fiber Bragg gratings (FBG) was observed and analyzed in this paper. It was demonstrated that the micro-bending of the fiber in the ferrule would cause friction between fiber and inner wall of the ferrule, and the friction would make a non-uniform strain in the FBG and degradations of its reflection spectrum. To avoid the effect, some measures have been applied including reducing the ferrule diameter to fit the fiber, and filling some lubrication in the ferrule, and so on. Near 10 nm tuning range can be obtained with good spectral performance. 相似文献
947.
分别采用514 nm绿光4、88 nm蓝光和390 nm紫外光作为敏化光,633 nm红光作为记录光,详细研究了敏化光波长对氧化(Fe,Ni)∶LiNbO3晶体全息记录性能的影响。结果表明:随着敏化光波长的逐渐减小,氧化(Fe,Ni)∶LiNbO3晶体的非挥发全息记录性能逐渐优化,390 nm紫外光是这三种敏化光中最优的敏化光。考虑敏化光的吸收,为了在双中心全息记录中获得最优的性能,应当选择合适波长的敏化光:一方面短波长敏化光能有效地敏化深中心;另一方面短波长敏化光的吸收太强(如对光折变效应无用的基质吸收),不能沿厚度方向有效地敏化晶体,所以实际上需折衷考虑,并从理论上给予了解释。 相似文献
948.
949.
Wei‐Yu Bi Xing‐Qiang Lü Wen‐Li Chai Ji‐Rong Song Wai‐Kwok Wong Xiao‐Ping Yang Richard A. Jones 《无机化学与普通化学杂志》2008,634(10):1795-1800
Two heterobimetallic Zn‐Nd phenylene‐bridged Schiff‐base ligands complexes [ZnNd L1 (Py)(NO3)3] ( 1 ) and [Zn L2 Nd(Py)(NO3)3]·MeCN ( 2 ) (Py = pyridine, H2L1 = N,N′‐bis‐ (3‐methoxy‐salicylidene)phenylene‐1,2‐diamine, H2L2 = N,N′‐bis‐5‐bromo‐3‐methoxy‐salicylidene)phenylene‐1,2‐diamine) were obtained. Both 1 and 2 were structurally characterized by X‐ray crystallography, and their near‐infrared (NIR) luminescent properties were determined. For the two complexes, the occupation of pyridine at the axial position of 3d Zn2+ ions could effectively prevent luminescent quenching arising from OH‐, NH‐ or CH oscillators of the solvates around the 4f Nd3+ ions, and the heavy‐atom (Br) effect of the Schiff‐base ligands on their NIR luminescent properties is also discussed. 相似文献
950.
Mathematische Zeitschrift - 相似文献