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1994年, 第3卷, 第6期　刊出日期：1994-06-20 上一期    下一期

ATOMIC AND MOLECULAR PHYSICS

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STUDY OF THE POLARIZATION SPECTROSCOPY OF 3p RYDBERG STATES OF m-DIMETHYLBENZENE 刘耀明, 林美荣, 张包铮, 赵青春, 陈文驹 1994 (6):  401-405.  doi: 10.1088/1004-423X/3/6/001 摘要 ( 1503 )   PDF(156KB) ( 344 )   A polarization-selected three-photon resonant multiphoton ionization investigation of the 3p Rydberg region of the spectra of m-dimethylbenzene has been conducted. Several vibronic states have been discovered and also assigned for the first time. 相关文章 | 计量指标

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ANALYSIS OF THE LASER-INDUCED FLUORESCENCE IN CRYSTAL Cr:Mg2SiO4 郭祥义, 杨宝成, 沈国土, 林远齐, 祝生祥, 潘佩聪 1994 (6):  406-412.  doi: 10.1088/1004-423X/3/6/002 摘要 ( 1229 )   PDF(190KB) ( 433 )   Observation of the 532 nm-laser-induced fluorescence spectra of two kinds of Cr:Mg2SiO4 crystalline samples grown in different atomsphere are reported. The experiments were con-ducted at both room temperature and liquid-nitrogen temperature. The fluorescence spectra of the two kinds of samples were different with respect to the polarizing direction of the inducing leser, and two emission bands with different polarized characters and various en-hancement in intensity at low temperatures were also found. In the light of the calculated results by Ms-Xα method, the main experimental results are explained. 相关文章 | 计量指标

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INTERSUBBAND OPTICAL ABSORPTION IN SEMICONDUCTOR SUPERLATTICES WITH COMPLEX BASES 史俊杰, 戴宪起, 潘少华 1994 (6):  413-425.  doi: 10.1088/1004-423X/3/6/003 摘要 ( 1465 )   PDF(274KB) ( 395 )   The third-order nonlinear intersubband optical absorption coefficient within the con-duction band of semiconductor superlattices with complex bases have been calculated using the density matrix formalism including intrasubband and intersubband relaxation. The sub-band dipole moments zij(k) and zii(k) are first studied in superlattices with complex bases including a general coupled-well basis and a general step-well basis. The results show that zij(k) and zii(k) are complicated functions of and strongly depends on the well parameters. The intersubband transition optical absorption coefficient α(ω,I) is further studied. The numerical illustrations are also given. 相关文章 | 计量指标

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ELECTRICAL RESISTIVITY OF NANOCRYSTALLINE Fe-Cu-Si-B ALLOYS 刘学东, 卢柯, 丁炳哲, 胡壮麒, 王永忠 1994 (6):  426-430.  doi: 10.1088/1004-423X/3/6/004 摘要 ( 1310 )   PDF(154KB) ( 389 )   We have studied the room temperature and low-temperature electrical resistivities of nanocrystalline Fe-Cu-Si-B alloys with various grain sizes prepared by crystallization of amor-phous material. Experimental results showed that with the reduction of grain size both room temperature resistivity ρRT and residual reaistivity ρ0 of the nanostructured alloys studied increased significantly. Based on the scattering effects from interfaces and lattice distortion, the above results were qualitatively discussed. 相关文章 | 计量指标

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

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SIMULATION OF X-RAY DIFFRACTION OF MULTILAYER FILM WITH INTERFACIAL ROUGHNESS 高琛, 刘文汉, 吴自勤 1994 (6):  431-438.  doi: 10.1088/1004-423X/3/6/005 摘要 ( 1243 )   PDF(216KB) ( 397 )   In this paper, the X-ray diffraction profiles of multilayer with uncorrelated rough interfaces are directly simulated using kinematic theory of X-ray diffraction. The result shows that the decrease of the reflective intensity caused by the interracial roughness is more severe than that caused by random fluctuation of period of the same degree, and the decrease of the reflective intensity of high order Bragg deffraction is more rapid than that of low order ones. So it is very important to reduce the interracial roughness in the deposition and in the annealing of multilayer films. 相关文章 | 计量指标

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RADIATION-INDUCED DEFECTS IN RADIATION HARD AND SOFT OXIDES 刘昶时, 马忠权, 赵元富 1994 (6):  439-444.  doi: 10.1088/1004-423X/3/6/006 摘要 ( 1236 )   PDF(166KB) ( 357 )   The point defects of Pb and E′ in radiation hard and soft Si-SiO2 samples were examined using electron spin resonance (ESR). The experimental results showed that these defects were correlated with the ways of oxidation process, the dosage of 60Co radiation and the radiation bias field. Besides, the ΔH (peak of peak) of Pb and E′ indicated that Pb is the defect with slow electron spin relaxation time while E′ is the defect with fast electron spin relaxation time. Finally, the experimental results are explained qualitatively. 相关文章 | 计量指标

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PROPERTIES OF TEMPERATURE DEPENDENCE OF THRESHOLD IN PURE AND IMPUHITY-DOPED BLUE BRONZES 田明亮, 毛志强, 张裕恒, 张一民, 石兢, 田德诚 1994 (6):  445-452.  doi: 10.1088/1004-423X/3/6/007 摘要 ( 1145 )   PDF(210KB) ( 450 )   Temperature dependence of the threshold of pure and impurity-doped blue bronzes has been studied. It is found that for pare blue bronzes the threshold field near 100K has an anomalous peak, but for impurity-doped samples no anomaly is observed in the range of liquid nitrogen temperature, and the value of the threshold field gradu-ally increases with the decrease of temperature. The results show that in the high-quality pure blue bronzes, there may exist an incommensurate to quasi-commensurate transition near 100K. But for the impurity-doped or "dirty" pure samples, such an incommensurate to quasi-commensurate transition near 100K can be extensively re-strained by impurities or defects, which leads to a pure incommensurate CDW in a wide temperature range. 相关文章 | 计量指标

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FAR-INFRARED PHOTOCONDUCTIVITY MECHANISM ON SHALLOW IMPURITY IN GaAs 陈忠辉, 刘普霖, 周涛, 史国良, 陆卫, 黄醒良, 沈学础 1994 (6):  453-459.  doi: 10.1088/1004-423X/3/6/008 摘要 ( 1169 )   PDF(196KB) ( 353 )   We report the far-infrared photoconductivity spectroscopy (FIRPCS) of the high purity n-GaAs grown by molecular beam epitaxial (MBE) technique. The current-voltage (I-V) measurement and FIRPCS under different electric field strength have been performed on high purity n-GaAs at 4.2K. Except for photothermal ionization process, a new far-infrared photoconductivity (FIRPC) mechanism is observed. This photo ionization process is assisted by impact ionization and depends on external electric field. This new mechanism originates from photo-field ionization. 相关文章 | 计量指标

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MAGNETIC PROPERTIES OF NEW SERIES R-Mo-Fe NITRIDES WITH THE ThMn12-TYPE STRUCTURE AT A LOWER Mo CONTENT 潘琪, 张晓东, 张明厚, 杨应昌 1994 (6):  460-469.  doi: 10.1088/1004-423X/3/6/009 摘要 ( 1485 )   PDF(262KB) ( 334 )   A systematic study has been made on formation condition, crystallographic structure and magnetic properties of RMo1.5Fe10.5Nx, where R=Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er. The interstitial nitrogen atom effects on Curie temperature, saturation magnetization and magneto-crystalline anisotropy have been investigated. Two important preliminary results have been obtained. (1) A single phase crystallized in the ThMn12-type structure was stabilized with a smaller content of molybdenum, thus, the compounds possess a higher Curie temperature and a larger spontaneous magnetization. (2) A complete system of compounds with 1:12 type structure containing the light rare earth cerium and praseodymium was synthesized, which will be favorable for developing new rare earth hard magnetic materials. 相关文章 | 计量指标