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Volume 4 Issue 2
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Original Articles
CHAOTIC BEHAVIOR OF MHD FLOW IN A SHEARED MAGNETIC FIELD
QIU Xiaoming(S.M.Chiu), WANG Xiaogang*
Chin. Phys. Lett. 1987, 4 (2): 49-52 .  
Abstract   PDF(pc) (44KB) ( 474 )
A model on the Rayleigh-Benard problem of a non-ideal MHD flow in a sheared magnetic field is put forward and studied. Theoretical and numerical analyses on this model and its strange attractor show the existence of all three routes to chaos. Among the well-known models with these routes, so far, it is the unique one independent of an extrinsic periodic impelling.
OBSERVATION OF DENDRITIC PATTERNS IN ION IRRADIATED Ni-Mo FILMS
LIU Baixin, HUANG Liji, SHANG Changhe
Chin. Phys. Lett. 1987, 4 (2): 53-56 .  
Abstract   PDF(pc) (80KB) ( 430 )
Dendrites were observed for the first time in the Ni-Mo thin films irradiated by ion beam. Various patterns are presented and a typical one features no specific orientation. The formation of dendrites induced by ion beam is attributed to the critical phenomenon during amorphous to crystalline phase transformation.
THERMOELECTRIC POWER OF AMORPHOUS Nd0.06Fe0.94 AND Nd0.04Fe0.94B0.02 FILMS
TONG Litai, YANG Ke, ZHANG Yuxiang
Chin. Phys. Lett. 1987, 4 (2): 57-60 .  
Abstract   PDF(pc) (39KB) ( 434 )
Thermoelectric power measurements are reported for amorphous Nd0.06Fe0.94 AND Nd0.04Fe0.94B0.02 films. They provide the first examples which show that the thermoelectric power in magnetic glasses, contrary to the popular results, can be positive and non-linear, exhibiting a broad peak, as temperature varies.
ANOMALOUSLY AMPLITUDE DEPENDENT EFFECT OF THE LOW-TEMPERATURE INTERNAL-FRICTION PEAKS IN COLD-WORKED DILUTE ALUMINIUM-COPPER SOLID SOLUTION
GE Tingsui(T.S.Ke), YANG Shiqing, ZHU Zhengang
Chin. Phys. Lett. 1987, 4 (2): 61-64 .  
Abstract   PDF(pc) (53KB) ( 426 )
The composite internal friction peak (versus temperature) assumed to be consisted of a relaxation peak and a phase transformation peak previously observed in cold-worked Al-0.50wt% (0.21at%) Cu at temperatures below room temperature are now resolved into two separate peaks. Internal friotion peaks as a function of strain amplitude (the amplitude peak) are observed around the temperature region of both peaks for he first time.
A MONTE CARLO STUDY OF PERCOLATfON IN INHOMOGENEOUS SYSTEMS
PANG Gengdi, XIONG Shijie, CAI Jianhua*
Chin. Phys. Lett. 1987, 4 (2): 65-68 .  
Abstract   PDF(pc) (47KB) ( 415 )
The percolation critical line of an inhomogeneous system with simple cubic structure and periodic boundary condition is computed using a Monte Carlo method. We conclude that Hoshen and Kopelman's criterion applies to inhomogeneous systems, too. The implications on the localization of electron and phonon states in modulated alloys are also discussed.
A LIKELY EXTREMELY STRONG El TRANSITION
HO Yukun
Chin. Phys. Lett. 1987, 4 (2): 69-72 .  
Abstract   PDF(pc) (45KB) ( 509 )
It is predicted from the measured radiative width of the 2+2 state of 14C that the El transition strength from the state should exceed the old Recommended upper limit (RUL). Calculations in connection with this problem have been surveyed. It is suggested to measure the partial radiative widths to identify this prediction.
PHOTOACOUSTIC STUDY ON SPECTRAL PROPERTIES OF OPTICAL FILMS
JIN Gang, CHOW Quantie
Chin. Phys. Lett. 1987, 4 (2): 73-76 .  
Abstract   PDF(pc) (60KB) ( 399 )
Photoacoustic method is developed to directly determine the absorption spectrum of optical films. For weak absorption, it has a higher precision than conventional spectrophotometric methods. With the aid of a carbon-black film, it can also be used to determine the transmission and reflection spectra. Measurements of some typical optical films are illustrated.
OBSERVATION OF BIFURCATIONS AND CHAOS IN SAW ON Y-Z LiNbO3
WEI Rongjue, ZHANG Shuyi, ZHOU Jianping
Chin. Phys. Lett. 1987, 4 (2): 77-80 .  
Abstract   PDF(pc) (55KB) ( 487 )
Bifurcations and chaos have been observed in surface acoustic waves propagating on the substrate LiNb03. We have discovered the second to sixth subharmonics, uttraharmonics, and the entering of the chaotic state which is manifested by the broadening and splitting of the subharmonic spectral lines.
DOES THE RADIO LUMINOSITY OF PULSAR GROW UP IN ITS LATER STAGE?
LU Tan*, ZHU Peichen, KUI Jisheng
Chin. Phys. Lett. 1987, 4 (2): 81-84 .  
Abstract   PDF(pc) (45KB) ( 558 )
In usual statistical analyses, because of diversities of proper parameters of pulsars, some interesting features might be smeared. In order to remove these diversities, we use the mean values for all quantities of pulsars, instead of values of individual one to do statistical analyses. Logp/p3- log τ and LogL-log τ have been plotted. The most interesting feature is that the radio luminosity of pulsar evidently appears to regrow up after its initial dropping. This feature is difficult to understand in usual models. Two tentatlive interpretations have been given.
A NEW ON-DEMAND BEAM EXCITATION SYSTEM USED IN PIXE
LI Xiaomei, ZENG Xianzhou
Chin. Phys. Lett. 1987, 4 (2): 85-88 .  
Abstract   PDF(pc) (47KB) ( 401 )
By using a symmetrical driving method of electrostatic deflecting field, a new all-transistorized on-demand beam pulsing system for Particle-Induced X-ray Emission (PIXE) analysis has been made. The measured rise time of the electrostatic field is less than 35ns; the pile-up continuum in PIXE spectrum is greatly suppressed, and the counting rate reaches as high as 20,000 counts per second.
EFFECTS OF DISORDER ON POLARIZATION OF ELECTRONS
ZHU Shiyao, CHEN Yinli, FANG Junxin
Chin. Phys. Lett. 1987, 4 (2): 89-92 .  
Abstract   PDF(pc) (45KB) ( 584 )
The Anderson Model has been extended to a disordered system interacting with light field. A method to obtain polarization of electrons of the system is given, where the disordered system is treated as a crystal plus a disordered revision. Criterions for determining whether the method is valid or not for Gaussian distribution disorder and homogeneous disorder have been derived.
THE PROPAGATION OF A LASER PULSE THROUGH AN OPTICALLY THICK HYDROGEN PLASMA-AN EXAMINATION OF THE COLLISIONAL RADIATIVE MODELS OF THE ATOMIC HYDROGEN SYSTEM
DING Ruiqin*, Geoffry Kolbe**, D. D. Burgess
Chin. Phys. Lett. 1987, 4 (2): 93-96 .  
Abstract   PDF(pc) (36KB) ( 374 )
The Collisional-Radiative Models(CRM) of hydrogen are used in the experiments of a resonant H-α laser pulse through an optically deep hydrogen plasma. Several causes for the disagreement between the theoretical predictions and experimental results are discussed.
12 articles