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Hyperon Halos in Λ Hypernuclei in the Relativistic Continuum Hartree-Bogoliubov Theory
LÜ, Hong-Feng, MENG Jie,
Chin. Phys. Lett. 2002, 19 (12):
1775-1778
.
We investigate the existences of a single-Λ hyperon halo in 153ΛC and a two-Λ hyperon halo in 164ΛC. Ground-state properties of hyperon carbon isotopes, such as density distributions, single particle levels in the canonical basis, the binding energy, Λ separation energy and radii, are calculated and discussed by using the relativistic continuum Hartree-Bogoliubov theory. The hyperon halo phenomenon in 153ΛC and 164ΛC is supported by the discussion on the weakly bound state 1p3/2, extended density distribution and small separation energy of the Λ hyperon.
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Search for the Chiral Band in the N = 71 Odd-Odd Nucleus 126Cs
LI Xian-Feng, MA Ying-Jun, LIU Yun-Zuo, LU Jing-Bin, ZHAO Guang-Yi, YIN Li-Chang, MENG Rui, ZHANG Zhen-Long, WEN Li-Jun, ZHOU Xiao-Hong, GUO Ying-Xiang, LEI Xiang-Guo, LIU Zhong, HE Jian-Jun, ZHENG Yong
Chin. Phys. Lett. 2002, 19 (12):
1779-1781
.
High-spin states in 126Cs are studied via the 116Cd(14N, 4n) reaction at a beam energy of 65 MeV. The sideband of the πh11/2 vh11/2 yrast band, a ΔI = 2 band known from previous study, is developed into a ΔI = 1 coupled structure at low spins. This sideband is assigned to be built on the same configuration as the yrast band according to the measured ratios of directional correlation of orientation and observed alignment properties. On the basis of comparisons with the previously proposed chiral doublet bands for 128,130Cs, the observed two πh11/2 vh11/2 bands are proposed to be candidates for chiral doublet bands in 126Cs.
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Electron Momentum Spectroscopy of the Frontier Orbitals of Chlorodifluoromethane
XU Chun-Kai, CHEN Xiang-Jun, JIAChang-Chun, ZHANG Xu-Huai, YIN Xiao-Feng, SHAN Xu, WEI Zheng, XU Ke-Zun
Chin. Phys. Lett. 2002, 19 (12):
1795-1797
.
We report on the first measurement of the electron momentum distributions of the three outermost valence orbitals for chlorodifluoro-methane (CHF2Cl) by a binary (e, 2e) electron momentum spectroscopy. The experimental data are compared with Hartree-Fock and density functional theory (DFT) calculations employing 6-31 G, 6-311++G** and AUG-cc-pVQZ basis sets. For the summed momentum distribution of 8a'+5a''+7a' orbitals, the DFT/AUG-cc-pVQZ calculation gives the best fit. A very large and diffuse basis set, AUG-cc-pVQZ, is employed in the calculations to approach the Hartree-Fock limit of basis set, but improvement of the calculation quality is little in comparison with that calculated with 6-311++G** basis set. This indicates that 6-311++G** basis set is nearly saturated for the calculations of these three orbitals of CHF2Cl, and it is unnecessary to employ a larger basis set in the calculations.
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Acoustic Nonlinear Behaviour of Microbubble Contrast Agent
YU Jin-Fei, LU Rong-Rong, GONG Xiu-Fen, William T. Shi
Chin. Phys. Lett. 2002, 19 (12):
1828-1830
.
We have investigated the nonlinear characteristics of a microbubble contrast agent SonazoidR (Nycomed, Norway), including the second, third, 1/2-order, 3/2-order and 5/2-order harmonics. We have measured the 1/2-order subharmonic response to different transmit sound pressure. It is found that subharmonic signals can not be generated until the acoustic pressure reached a certain value, which is the most difference subharmonic from high harmonics. This result is favorable for the further study of the subharmonic in the bubbly liquid. The 3/2-order ultraharmoic response to acoustic pressure was also measured.
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Pt/Au Schottky Contacts to Modulation-Doped AlxGa1-xN/GaN Heterosturctures Using Pre-deposition Surface Treatment
LIU Jie, SHEN Bo, WANG Mao-Jun, ZHOU Yu-Gang, ZHENG Ze-Wei, ZHANG Rong, SHI Yi, ZHENG You-Dou, T. Someya, Y. Arakawa
Chin. Phys. Lett. 2002, 19 (12):
1853-1855
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Pt/Au Schottky contacts were fabricated on modulation-doped Al0.22GaN0.78/GaN heterostructures. Some different pre-deposition surface treatments were used to prevent the formation of the native oxide layer on the Al0.22GaN0.78 surface. X-ray photoelectron spectroscopy (XPS) measurements indicate that the pre-deposition surface treatment with boiling (NH4)2S solution can remove the native oxide layer on the Al0.22GaN0.78 surface effectively. The highest Schottky barrier height of 1.13 eV was obtained on the (NH4)2S-treated Al0.22GaN0.78 heterostructure.
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Substantial Enhancements of Low-Field Magnetoresistance at Temperatures near 77 K with Doping 4% Cu at Mn Sites of La2/3Ca1/3MnO3 Synthesized at 1000°C
YUAN Song-Liu, ZHANG Guo-Hong, LIU Li, TANG Jie, ZHANG Li-Jiang, ZHONG Qiang-Hua, YANG Ying-Ping, FENG Wen, LIU Sheng, CHEN Wei, XIA Zheng-Cai
Chin. Phys. Lett. 2002, 19 (12):
1866-1869
.
We report on investigations of magnetoresistance (MR) in polycrystalline La2/3Ca1/3Mn1-xCuxO3 (x = 0 and 4%) samples prepared by the sol-gel method followed a sintering treatment at 1000°C. For the x = 4% sample, the most remarkable MR effect appears at temperatures near 77 K and for magnetic fields lower than 1 T. For fields ~ 0.3 T and at temperatures ~ 77 K, the x = 4% sample exhibits giant MR effect with M0 (≡ Δρ/ρ (H = 0)) between ~ 50 and ~ 70%, comparable to the so-called colossal MR response observed in the x = 0 sample for the 3 T field.
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Phenomenon of Energy Concentration in High-Energy Family Events of Cosmic Rays
WANG He, WANG Yong-Gang, DAI Zhi-Qiang, XUE Liang, FENG Cun-Feng, ZHANG Xue-Yao, LI Jin-Yu, ZHANG Nai-Jian, HE Mao, WANG Cheng-Rui, REN Jing-Ru, LU Sui-Ling
Chin. Phys. Lett. 2002, 19 (12):
1890-1892
.
The phenomenon of energy concentration in high-energy family events of cosmic rays is studied by comparing the results of family events of total visible energies 100-400 TeV observed in Kanbala emulsion chamber experiment with the Monte Carlo simulation data. The simulation is made by program CORSIKA in which QGSJET is applied as the hadronic interaction model, and the chemical composition of primary cosmic rays is obtained from the rigidity-cut model and the extrapolation of new results of direct measurements. This shows that the whole distribution tendency of the rate of energy concentration of simulated family events is basically consistent with that of the experiment.
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45 articles
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