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An Automated Algebraic Method for Finding a Series of Exact Travelling Wave Solutions of Nonlinear Evolution Equations
LIU Yin-Ping, LI Zhi-Bin
Chin. Phys. Lett. 2003, 20 (3):
317-320
.
Based on a type of elliptic equation, a new algebraic method to
construct a series of exact solutions for nonlinear evolution equations is proposed, meanwhile, its complete implementation TRWS in Maple is presented. The TRWS can output a series of travelling wave solutions entirely automatically, which include polynomial solutions, exponential function solutions, triangular function solutions, hyperbolic function solutions, rational function solutions, Jacobi elliptic function solutions, and Weierstrass elliptic function solutions. The effectiveness of the package is illustrated by applying it to a variety of equations. Not only are previously known solutions recovered but also new solutions and more general form of solutions are obtained.
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Structure of the Semi-decoupled π 1/2[411] Band in Odd Proton Nucleus 169Ta
SONG Hai, YANG Chun-Xiang, , SUN Hui-Bin, DENG Fu-Guo, WU Xiao-Guang, LU Jing-Bin, ZHAO Guang-Yi, HAN Guang-Bing, PENG Chao-Hua, YIN Li-Chang, WEN Shu-Xian, LI Guang-Sheng, YUAN Guan-Jun, LIU Yun-Zuo, ZHU Li-Hua, SHAO Li-Qin, ZHOU Hong-Yu,
Chin. Phys. Lett. 2003, 20 (3):
346-349
.
High spin states of the odd proton-nucleus 169Ta have been populated in the reaction 155Gd(19F, 5n) with beam energies of 97 MeV. Rotational band based on d3/2 proton 1/2[411] Nilsson state has been pushed up to 39/2+ in the α = 1/2 decay sequence. Its signature partner, the α = -1/2 decay sequence with four link transitions has been established and 1/2[411] band in 169Ta was reassigned to be a semi-decoupled band. The systematics of the signature splitting in the K = 1/2 bands in the rear-earth region and the accidental degeneracy conclusion given by the angular projection shell model were discussed.
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Collective Bands in Neutron-Rich 110Ru Nucleus
JIANG Zhuo, ZHU Sheng-Jiang, J. H. Hamilton, A. V. Ramayya, J. K. Hwang, ZHANG Zheng, XU Rui-Qing, XIAO Shu-Dong, CHE Xing-Lai, YU Yong-Nan, W. C. Ma, J. D. Cole, M. W. Drigert, I. Y. Lee, J. O.Rasmussen, Y. X. Luo,
Chin. Phys. Lett. 2003, 20 (3):
350-353
.
High spin states in neutron-rich 110Ru nucleus have been investigated by measuring high-fold prompt γ-ray coincidence events of the spontaneous fission of 252Cf with the Gammasphere detector array. The ground-state band and the γ-vibrational band have been confirmed and extended with spin up to 18ħ and 13ħ, respectively. The other three side bands, two proposed as two-quasiparticle bands and one proposed as a four-quasiparticle band,have been observed for the first time. The possible configurations for the quasi-particle bands are discussed. The cranked shell model calculations show that 110Ru nucleus may have oblate triaxial deformation with parameters β2 = -0.30 and γ = 24°, and the band crossing in the yrast band is due to the alignment of a pair of h11/2 neutrons.
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Total Reaction Cross Section in an Isospin-Dependent Quantum Molecular Dynamics Model
WEI Yi-Bin, CAI Xiang-Zhou, SHEN Wen-Qing, , MA Yu-Gang, ZHANG Hu-Yong, ZHONG Chen, GUO Wei, CHEN Jin-Gen, MA Guo-Liang, WANG Kun
Chin. Phys. Lett. 2003, 20 (3):
354-357
.
The isospin-dependent quantum molecular dynamics (IDQMD) model is used to study the total reaction cross section σR. The energy-dependent Pauli volumes of neutrons and protons have been discussed and introduced into the IDQMD calculation to replace the widely used energy-independent Pauli volumes. The modified IDQMD calculation can reproduce the experimental σR well for both stable and exotic nuclei induced reactions. Comparisons of the calculated σR induced by 11Li with different initial density distributions have been performed. It is shown that the calculation by using the experimentally deduced density distribution with a long tail can fit the experimental excitation function better than that by using the Skyrme-Hartree-Fock calculated density without long tails. It is also found that σR at high energy is sensitive to the long tail of density distribution.
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Pseudospin Symmetry in Relativistic Framework with Harmonic Oscillator Potential and Woods-Saxon Potential
CHEN Ti-Sheng, LÜ, Hong-Feng, MENG Jie, , ZHANG Shuang-Quan, ZHOU Shan-Gui,
Chin. Phys. Lett. 2003, 20 (3):
358-361
.
Based on the Dirac equation, we discuss the exact pseudospin symmetry and some examples are presented. For harmonic oscillator potential there exist bound states under the condition of the exact pseudospin symmetry, Vs+Vv = 0, and even usual intruder orbits will have degenerated pseudospin partners. Apart from the harmonic oscillator potential, a Woods-Saxon potential is introduced to eliminate the redundant degeneracies due to the speciality of harmonic oscillator potential except the pseudospin degeneracy.
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Temporal Skewness of Electromagnetic Pulsed Waves Propagating Through Random Media with Embedded Irregularity Slab
XU Zheng-Wen, WU Jian, HUO Wen-Ping, WU Zhen-Se
Chin. Phys. Lett. 2003, 20 (3):
370-373
.
Electromagnetic pulsed waves can be distorted in the propagation through random media, and their energy distributions change along the leading and trailing edge of the waveform, which can be presented by the temporal skewness. The skewness presents asymmetry and is treated by the third order temporal moment, in which an analytic solution for the two-frequency mutual coherence function is obtained recently. Then, transionospheric pulses are discussed in details. Both theoretical analysis and numerical computation indicate that the contributions from scattering and dispersion of irregularities dominate over those of background, so the latter can be neglected in most cases. Also, the temporal skewness of a transionospheric pulse is negative and energy is shifted to the leading edge.
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Etch Pits and Threading Dislocations in GaN Films Grown by Metal-Organic Chemical Vapor Deposition
LU Min, , CHANG Xin, LI Zi-Lan, , YANG Zhi-Jian, , ZHANG Guo-Yi, , ZHANG Bei,
Chin. Phys. Lett. 2003, 20 (3):
398-400
.
High quality epitaxial GaN films on (0001) sapphire substrates were grown by a commercial metal-organic chemical vapor deposition system. The etch-pits and threading dislocations in GaN films is studied by a scaning electron microscope (SEM) and a transmission electron microscope (TEM). The SEM images of GaN films etched in mixed acid solution (H3PO4:H2SO4 = 1:3) and molten KOH exhibit notably different etching pit densities of 5 x 108/cm2 and 4 x 107/cm2, respectively, which probably indicate that more kinds of etching pits were revealed when etched in mixed acid solution (H3PO4:H2SO4 = 1:3). Cross section TEM of GaN films with different g vectors showed the portions of different threading dislocations. Theoretical calculation indicates that the lattice and thermal expansion coefficient mismatch may be the main origins of pure edge threading dislocations.
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An a-C:F:H Film with High Thermal Stability by Electron Cyclotron Resonance Chemical Vapor Deposition at Room Temperature
XIN Yu, XU Sheng-Hua, NING Zhao-Yuan, LU Xin-Hua, JIANG Mei-Fu, HUANG Song, DU Wei, CHEN Jun, YE Chao, CHENG Shan-Hua
Chin. Phys. Lett. 2003, 20 (3):
423-426
.
Using CHF3/C6H6 gases, amorphous fluorinated hydrocarbon films (a-C:F:H) were deposited by electron cyclotron resonance (ECR) chemical vapor deposition at room temperature. Dependence of the film properties on variable flow ratios R[CHF3]/{[CHF3]+[C6H6]} was investigated by infrared absorption, x-ray photoelectron spectroscopy, measurements of the film thickness and dielectric constant. Evidences show that the film deposition rate decreases linearly with the increasing flow ratios R and the adding of C6H6 source gas to ECR plasma enhances structural cross-linking in the a-C:F:H films. In order to obtain good structural stability of these films, it is necessary to reconcile configurations between C-C bond and H or F terminal atoms carefully. The experimental results indicate that an a-C:F:H film with low dielectric constant (k < 3) and high thermal stability ( > 400°C) has been deposited successfully at R = 56.3%.
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37 articles
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