|
Measurements of Total Reaction Cross Section for Light Nuclei and Evidence for the Anomalous Nuclear Structure in 15C
FANG De-Qing, SHEN Wen-Qing, FENG Jun, CAI Xiang-Zhou, WANG Jian-Song, SU Qian-Min, ZHANG Hu-Yong, HU Peng-Yun, MA Yu-Gang, ZHU Yong-Tai, LI Song-Lin, WU He-Yu, GOU Quan-Bu, JIN Gen-Ming, ZHAN Wen-Long, GUO Zhong-Yan, XIAO Guo-Qing
Chin. Phys. Lett. 2000, 17 (9):
655-657
.
Measurements of the total reaction cross section for 12-16C, 14-17N and 16-18O on carbon target at intermediate energies were performed on RIBLL of HIRFL. A larger enhancement of σR for 15C was observed than that for its neighbors. The analysis of these data indicates possible existence of an anomalous nuclear structure in 15C. A new quantity was suggested as the criterion to distinguish anomalous structure nuclei from normal nuclei.
|
|
Observation of Electronic shells and Characteristic Products from Mass Abundance Spectra of AI Cluster and AI-C Cluster Anions
LIU Bing-Chen, ZHAI Hua-Jin, ZHOU Ru-Fang, NI Guo-Quan, XU Zhi—Zhan
Chin. Phys. Lett. 2000, 17 (9):
658-660
.
Using a laser vaporization/pulsed molecular beam cluster source, AI cluster anions and A1-C mixed cluster anions are produced and recorded by a time of flight mass spectrometer. Mass abundance spectra of the AI cluster anions in the size range from AI-2 to AI-42 show that AI-13, AI-23, AI-35, and slightly, AI-37 are local maxima, as predicted by the electronic jellium model. Mixed cluster AInC- and AInC-2 are also shown, among which the most abundant species are AI3C-2, AI6C-2,AI7C- and AI7C-2in the small size range. The formation mechanism of these products is discussed.
|
|
Scaling Law of Nonlinear Compton Scattering
WANG Ping-Xiao, HUO Yu-Kun, WANG Jia-Xiang, FENG Liang, KONG Qing
Chin. Phys. Lett. 2000, 17 (9):
666-668
.
We show that there are two mechanisms responsible for the net energy exchange between an intense pulsed laser and an electron in vacuum, namely, stimulated Compton scattering and nonlinear Compton scattering(NLCS). For NLCS, being the only effect in a mono-frequency continuous laser beam, its contribution is also independently determined. The characteristics of these two mechanisms in connection with the net energy exchange are studied. For the case of a pulsed laser field, it is found that the maximum net energy exchange by NLCS is approximately proportional to Q20(Q0 ≡ eE0/(me ωc)) for Q0 ≥100. In addition, the relative importance of these two mechanisms to the net energy exchange at different intensities is explored.
|
|
Thermal and Mechanical Properties of a Complex Nonlinear Optical Material: Cadmium Mercury Thiocyanate Crystal
YUAN Duo-Rong, XU Dong, ZHANG Guang-Hui, LIU Ming-Guo, GUO Shi-Yi, MENG Fan-Qing, LÜ, Meng-Kai, FANG Qi, JIANG Min-Hua
Chin. Phys. Lett. 2000, 17 (9):
669-671
.
The data of the thermal expansion and specific heat of cadmium mercury thiocyanate crystal have been obtained. The specific heat is 0.7588 J/g.oC at room temperature. The thermal expansion occurs in the direction parallel to the c-axis, and the thermal contraction occurs in the direction parallel to the a-axis. The thermal expansion is the same as the thermal contraction at 353 K. The relationship between thermal properties and crystal structure is discussed.
|
|
Propagation Properties of Quasi-longitudinal Leaky Surface Acoustic Wave on Y-Rotated Cut Quartz Substrates
TONG Xiao-Jun, WANG Wei-Biao, ZHOU Ran, ZHANG De, QIN Hou-Rong
Chin. Phys. Lett. 2000, 17 (9):
678-679
.
Propagation properties of the quasi-longitudinal leaky surface acoustic wave (QLLSAW) along different directions on Y-rotated cut quartz substrates, such as on the 34o, 36o, 42o Y-rotated cut, are investigated. The advantages of the QLLSAW along some directions include low propagation attenuation (less than 10-4dB/λ), small power flow deviation and high phase velocity which can be up to 7000 m/s. A novel propagation direction of the quasi-longitudinal leaky surface acoustic wave with the theoretical temperature coefficient of delay of 0.508 ppm/oC is proposed.
|
|
New Age Indicators for Stellar Populations
KONG Xu, , CHENG Fu-Zhen,
Chin. Phys. Lett. 2000, 17 (9):
700-702
.
We apply the method of principal component analysis to a sample of simple stellar populations to select some age sensitive spectral indices. Besides the well-known age sensitive index Hβ, we also find some new age sensitive indices, G4300 and Fe4383, C24668, and Mgb. In addition, we find that these spectral indices sensitive to age depend on the metallicity of stellar population, Hβ and G4300 are more suitable to determine the age of low metallicity stellar population, while C24668 and Mgb are more suitable to the high metallicity stellar population.
|
27 articles
|