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(EC+β+) Decay of 128Ce
LI Zhan-Kui, XU Shu-Wei, XIE Yuan-Xiang, ZHANG Tian-Mei, MA Rui-Chang, GUO Ying-Xiang, GE Yuan-Xiu, WANG Chun-Fang, GUO Bin, XING Jian-Ping, DU Jin-Zhou
Chin. Phys. Lett. 2000, 17 (11):
787-788
.
The (EC+β+) decay of 128Ce was reinvestigated in the116Sn (l6O, 4n) reaction by using a helium-jet tape transport system. The decay γ rays of 128Ce were unambiguously described from those of 129Ce after taking the comparing experiments of 16O+116Sn and 16O+117Sn. Based on x-γ and γ-γ coincidence measurements, a detailed (EC+β+) decay scheme of 128Ce has been proposed which modifies the previous one, and takes accounts of 100 observed γ-lines.
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Momentum Profile and Final Correlation Effects of Iso-butane Inner Valence by Binary (e, 2e) Spectroscopy
DENG Jing-Kang, LI Gui-Qin, HE Yao, HUANG Jian-Dong, DENG Hui, WANG Xiao-Dong, WANG Fang, ZHANG Yi-An, NING Chuan-Gang, GAO Nai-Fei, WANG Yan, CHEN Xue-Jun, ZHENG Yan-You
Chin. Phys. Lett. 2000, 17 (11):
795-797
.
The binding energy spectra and the momentum distributions of the valence orbitals of iso-butane, also known as methylpropane (CH3CH(CH3)CH3), are studied by using a high resolution binary (e, 2e) electron momentum spectrometer, at an impact energy of 1200eV plus the binding energy (8-32eV) with symmetric non-coplanar kinematics. Binding energy spectra of the valence shell are obtained at a coincidence energy resolution of 0.95 eV in full width at halfmaximum. The experimental momentum profiles of the inner valence orbitals are obtained and compared with the theoretical momentum distributions calculated by using Hartree-Fock and density functional theory methods with the basis sets 6-31G and 6-311++G**. The pole strengths of the inner orbitals are estimated and the final correlation effects are discussed.
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Enhancement of Curie Temperature and Magnetoresistance in the
Perovskit es La2/3Cal/3Mnl-xSixO3
LI Run-Wei, WANG Zhi-Hong, SUN Ji-Rong, CHEN Xin, SHEN Bao-Gen
Chin. Phys. Lett. 2000, 17 (11):
832-834
.
Structural, magnetic, and transport properties of perovskite La2/3Cal/3Mnl-xSixO3(x = 0, 0.025, 0.05) have been studied. The incorporation of Si decreases the overall resistivity, but obviously increases the Curie temperature (TC), metal-insulator transition temperature (TP), and the magnetoresistance ratio MR (defined as [R(0) - R(H)]/R(0)) near room temperature. Comparing with La2/3Cal/3MnO3 the TC , TP, and MR of the sample with x = 0.05 increase by 30, 45K, and 20%, respectively. Lattice effects may play a more important role than the magnetic dilution in the case of low Si substitution.
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Photoluminescence and Microstructure of the Erbium-Doped Hydrogenated Amorphous SiOx(O < x < 2)
LIANG Jian-Jun, , CHEN Wei-De, , WANG Yong-Qian, , HE Jie, , ZHENG Wei-Min, WANG Zhan-Guo
Chin. Phys. Lett. 2000, 17 (11):
838-840
.
The hydrogenated amorphous SiOx films (a-SiOx:H) with various oxygen contents have been prepared using plasma enhanced chemical vapor deposition technique. The films were implanted with erbium and annealed by rapid thermal annealing. An intense photoluminescence (PL) of Er at 1.54μm has been observed at 77K and at room temperature. The PL intensity depends strongly on both the oxygen content of the film and the rapid thermal annealing temperature and reaches its maximum if the ratio of O/Si in the film is approximately equal to 1.0 at 77K and to 1.76 at room temperature. The microstructure of the film also has strong influences on the PL intensity. The PL intensity at 250K is slightly more than a half of that at 15K. It means that the temperature quenching effect of the PL intensity is very weak.
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Some New Observing Features of a Solar Radio Spectral Event
on August 25,1999
XU Fu-Ying, LIU Yu-Ying, YAO Qi-Jun, FU Qi-Jun, MENG Xuan, WU Hong-Ao
Chin. Phys. Lett. 2000, 17 (11):
850-852
.
A broadband solar radio type III burst was observed on August 25,1999 at Purple Mountain Observatory with waveband of 4.5-7.5 GHz. It was also observed at Beijing Astronomical Observatory with waveband of 5.2-7.6 GHz. Therefore, it is the first common spectral event observed in China. The type III bursts are gathered into more than 10 groups and drift in opposite directions, but the reverse drifting prevails. The largest bandwidth of type III burst reaches ≥3 GHz and may be the broadest bandwidth of the reverse type III burst ever observed up to the present. Some new observing characteristics of fine structures are found, for example, fiber-like, V-shaped and neck-ring-like structures. Especially, the neck-ring-like structure is probably first discovered in cm waveband and may be the evidence of twisted rope of magnetic lines.
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27 articles
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