共查询到20条相似文献,搜索用时 140 毫秒
1.
μ子动量谱的精确测量是L3C宇宙线实验最重要的目标之一.事例重建的好坏是该测量的关键,而能量确定的衰变为双μ子的事例是检验重建程序的最好手段.该数据分析利用在2000年中获取的数据作为样本,筛选出了LEP在2000年4月、5月、8月和9月等Z0能量运行期间L3C宇宙线实验数据中记录的Z0→μ+μ-事例数据,得到通过重建程序后动量为45GeV的μ子动量分辨率为(5.4?7±0.25)%. 相似文献
2.
3.
4.
通过对北京谱仪(BES)所记录到的宇宙线事例的挑选和校正重建,得到了BES上数量很大、动量分布宽广的高纯度的μ样本.所得样本已经用于Ds物理研究. 相似文献
5.
6.
7.
8.
9.
10.
从甘巴拉山乳胶室中选取18个大天顶角(θ≥70°)事例, 对这些事例进行了初步分析. 从而给出μ子在产生能量大于3TeV时的电磁簇射流强与能谱. 相似文献
11.
Very high purity single crystals have been successfully grown by the method of vertical zone refining. The problem of excessive evaporation of the material, confronted by the earlier workers, has been successfully overcome. The purity of the crystals has been tested by D. C. conductivity measurements and further confirmed by U. V. spectroscopy. X-ray diffraction has been employed for the characterization of the crystals. The crystals have been found to crystallize exclusively in 6R polytypic modifications, without any arcing and streaking on their X-ray photographs. The results have been discussed in relation to the effect of impurities on polytype formation. 相似文献
12.
13.
研究了行波管中均匀聚焦磁场和周期永磁聚焦磁场对轨迹波动的影响。推导了这两种磁场下轨迹波动周期和幅值,讨论了磁场强度对轨迹的影响。解释了聚焦磁场存在小的波动的原因,并且通过计算得出小波动的周期为磁场周期的1/2,揭示了在周期永磁聚焦磁场下,电子轨迹近似等效于周期为周期永磁聚焦磁场1/2的小波动和均匀磁场形成的波动轨迹的叠加。利用电子科技大学编写的微波管模拟套装中的3维注-波互作用模块进行了静态轨迹计算,验证了理论推导。 相似文献
14.
Three phase transitions between 100 and 400 K were previously shown by X-ray diffraction measurements. Such results have been confirmed by optical measurements on crystals. The thermal dependence of the birefringence has been determined. A new phase transformation has been shown at around 590 K not only by optical study but also by dielectric measurements. Ferroelastic domain-walls have been visualized. The sequence transition has been discussed taking into account the various space groups. 相似文献
15.
V. Antoni M. Bagatin A. Buffa G. Della Mea F. Freyre Jr. P. Mazzoldi F. Romanato 《Il Nuovo Cimento D》1991,13(4):435-453
To investigate the ion flux escaping from the plasma and the impurity flux released by the wall, collector probes made of
graphite, silicon and titanium have been exposed to the deuterium plasma confined in the toroidal device ETA BETA II. The
damages on the collector surfaces have been surveyed by a scanning electron microscopy (SEM) apparatus. The deuterium and
impurity retention have been measured by elastic recoil detection (ERD) and Rutherford backscattering spectroscopy (RBS) techniques
respectively. The implantation build-up has been investigated as a function of the exposure time. The deuterium dose in graphite
saturates after a few discharges, whereas the metal impurities exhibit a linear increase in time. The deuterium flux and its
radial dependence, inferred from the implanted concentrations, have been compared with those measured by Langmuir probes.
Metal impurities have been identified and their relative abundances have been compared with the material wall composition.
The impurity flux is found consistent with the global content in the plasma derived by spectroscopic measurements. The deuterium
dose measured in different samples has been related to the backscattering coefficient of the materials. Finally, to investigate
the damage on sample probes facing the plasma particle flow, erosion probes made of vitreous graphite with silver implanted
at a fixed depth have been exposed to the plasma and the thickness change after exposure recovered. 相似文献
16.
Wei ZhongXiangdong Zhang 《Physics letters. A》2011,375(40):3533-3536
Acoustic analog of monolayer graphene has been designed by using silicone rubber spheres of honeycomb lattices embedded in water. The dispersion of the structure has been studied theoretically using the rigorous multiple-scattering method. The energy spectra with the Dirac point have been verified and zigzag edge states have been found in ribbons of the structure, which are analogous to the electronic ones in graphene nanoribbons. The guided modes along the zigzag edge excited by a point source have been numerically demonstrated. The open cavity and “Z” type edge waveguide with 60° corners have also been realized by using such edge states. 相似文献
17.
18.
Formation and microstructural investigation of Ag-Cu alloy nanoclusters embedded in SiO2 formed by sequential ion implantation 总被引:1,自引:0,他引:1
We report on the formation of alloy nanoclusters in silica by Ag/Cu ion sequential implantation. The formation of alloy nanocluster has been evidenced by optical absorption spectra, selected area electron diffraction and energy dispersive X-ray spectra. The microstructure characters of nanoclusters have been studied by high resolution transmission electron microscopy. The lattice distortion of some nanoclusters has been observed. A model has been given to explain the distortion. Some defects (partial dislocation, stacking faults) have been found in nanoclusters. 相似文献
19.
4-Dimethylaminobenzaldehyde-4-nitrophenylhydrazone (DANPH) single crystals exhibit polymorphism such as DANPH-G form (greenish red) and DANPH-R form (red). The different polymorphic phases of the grown crystals have been identified by X-ray diffraction studies. The functional groups of the crystals have been identified by FT-IR study. Crystallographically independent environment of polymorphs has been confirmed by NMR study. The thermal properties such as melting and decomposition temperatures of the compound have been analyzed. Optical constants of DANPH polymorph crystals have been calculated. 相似文献
20.
The two pulse photon echo (2PPE) phenomena induced by the 1s-1s electronic transition in CdSe/ZnS quantum dot quantum well (QDQW) has been studied by employing semiconductor Bloch equations. The energy eigenvalues and eigenfunctions of electrons and holes have been obtained by solving the stationary Schrödinger equation under effective-mass approximation. The Coulomb interaction, which changes with the size variation of QDQW, has been calculated and analyzed as a perturbation. The variations of the electric transition dipole moment and the energy interval with the changing of the size and structure of the QDQW have also been obtained. It has been shown from the numerical calculation results that the efficiency of 2PPE can be controlled by the variation of the size and structure of the QDQW and the mechanism has been explained in terms of the quantum size confined effect (QSCE) theory. 相似文献