Pub Date : 1999-12-01DOI: 10.1088/1004-423X/8/12/009
Wu Jin, Xie Fang-qing, Zhang Qing-zhe, Liu Ji-wen, Chen You-cun, Lin Zhang-Da
Partially oriented and highly textured diamond films on Si(111) substrates were achieved by hot-filament chemical vapor deposition(HFCVD). High nucleation density greater than 5 x 10(8) cm(-2) was realized in 3 min by near-surface glow discharge. The as-grown films were characterized. by scanning electron microscopy (SEM), X-ray diffraction(XRD) and Raman spectroscopy. It was found that by adding a small amount of oxygen to the mixture of CH4/H-2, the appearance of facet(111) was well controlled, and the secondary nucleation on the facet(111) was suppressed greatly. Growth feature of homoepitaxy on diamond(111) surface was demonstrated to be in Stranski-Krastanov model by SEM.
{"title":"GROWTH MODEL OF TEXTURED DIAMOND (111) FILM IN CH 4 /O 2 /H 2 ATMOSPHERE","authors":"Wu Jin, Xie Fang-qing, Zhang Qing-zhe, Liu Ji-wen, Chen You-cun, Lin Zhang-Da","doi":"10.1088/1004-423X/8/12/009","DOIUrl":"https://doi.org/10.1088/1004-423X/8/12/009","url":null,"abstract":"Partially oriented and highly textured diamond films on Si(111) substrates were achieved by hot-filament chemical vapor deposition(HFCVD). High nucleation density greater than 5 x 10(8) cm(-2) was realized in 3 min by near-surface glow discharge. The as-grown films were characterized. by scanning electron microscopy (SEM), X-ray diffraction(XRD) and Raman spectroscopy. It was found that by adding a small amount of oxygen to the mixture of CH4/H-2, the appearance of facet(111) was well controlled, and the secondary nucleation on the facet(111) was suppressed greatly. Growth feature of homoepitaxy on diamond(111) surface was demonstrated to be in Stranski-Krastanov model by SEM.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130483985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-12-01DOI: 10.1088/1004-423X/8/12/001
Liu Yong-cai, C. Wan-chun, Huo Chong-ru, Ge Pei-wen
The Kerr rotation of MnBixAl0.5(0.4 less than or equal to x 0.9) thin films with and Al protective layer as a function of the Bi concentration, x, has been investigated. Compared with MnBix thin films, it is found that a large enhancement of Kerr rotation appears in the MnBixAl0.15 thin films with 0.4 less than or equal to x less than or equal to 0.7, but no enhancement of Kerr rotation appears when x is greater than 0.7. When x = 0.5, a maximum Kerr rotation of 2.75 degrees is observed at 633 nm for the MnBi0.5Al0.15 thin film, which is much larger than that of 1.56 degrees for the MnBi0.5 thin film. For the MnBixAl0.15 thin films with 0.4 less than or equal to x less than or equal to 0.7, the c lattice shrinking may result in a stronger hybridization between Bi 6p and Mn 3d states, which also should be responsible for the large enhancement of Kerr rotation. In addition, the saturation magnetization M-s is reduced from 4 x 10(5) A/m for the MnBi0.5Al0.15 thin film to 3 x 10(5) A/m for the MnBi0.5Al0.15 thin film, suggesting that some of Al may also substitute for Mn at the octahedrtal sites.
{"title":"Interface shape and concentration distribution in crystallization from solution under microgravity","authors":"Liu Yong-cai, C. Wan-chun, Huo Chong-ru, Ge Pei-wen","doi":"10.1088/1004-423X/8/12/001","DOIUrl":"https://doi.org/10.1088/1004-423X/8/12/001","url":null,"abstract":"The Kerr rotation of MnBixAl0.5(0.4 less than or equal to x 0.9) thin films with and Al protective layer as a function of the Bi concentration, x, has been investigated. Compared with MnBix thin films, it is found that a large enhancement of Kerr rotation appears in the MnBixAl0.15 thin films with 0.4 less than or equal to x less than or equal to 0.7, but no enhancement of Kerr rotation appears when x is greater than 0.7. When x = 0.5, a maximum Kerr rotation of 2.75 degrees is observed at 633 nm for the MnBi0.5Al0.15 thin film, which is much larger than that of 1.56 degrees for the MnBi0.5 thin film. For the MnBixAl0.15 thin films with 0.4 less than or equal to x less than or equal to 0.7, the c lattice shrinking may result in a stronger hybridization between Bi 6p and Mn 3d states, which also should be responsible for the large enhancement of Kerr rotation. In addition, the saturation magnetization M-s is reduced from 4 x 10(5) A/m for the MnBi0.5Al0.15 thin film to 3 x 10(5) A/m for the MnBi0.5Al0.15 thin film, suggesting that some of Al may also substitute for Mn at the octahedrtal sites.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"07 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130005359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-12-01DOI: 10.1088/1004-423X/8/12/005
Wang Chuan-bing, Li Ding
The general dispersion relation for toroidally coupled tearing mode including pressure and other O(2) order corrections is naturally derived based on the structure of ideal magnetohydrodynamic solutions in the outer region. It is found that the inclusion of the O(2) order terms in the diagonal element of E-matrix does not change physical properties of the toroidally coupled tearing mode and only make negligible contribution to the magnitude of growth rate.
{"title":"Influence of higher order toroidicity on coupling of tearing modes","authors":"Wang Chuan-bing, Li Ding","doi":"10.1088/1004-423X/8/12/005","DOIUrl":"https://doi.org/10.1088/1004-423X/8/12/005","url":null,"abstract":"The general dispersion relation for toroidally coupled tearing mode including pressure and other O(2) order corrections is naturally derived based on the structure of ideal magnetohydrodynamic solutions in the outer region. It is found that the inclusion of the O(2) order terms in the diagonal element of E-matrix does not change physical properties of the toroidally coupled tearing mode and only make negligible contribution to the magnitude of growth rate.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132145933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-12-01DOI: 10.1088/1004-423X/8/12/002
Yan Zhen-ya, Zhang Hong-qing
In this paper, with the aid of Lax pairs, a new Backlund transformation for the variable coefficient KdV equation is found. Based on the Backlund transformation, only if integration is needed, a series of exact solutions can be obtained. This method is important for finding more new and physical-signficant solutions.
{"title":"New bäcklund transformation and exact solutions for variable coefficient KdV equation","authors":"Yan Zhen-ya, Zhang Hong-qing","doi":"10.1088/1004-423X/8/12/002","DOIUrl":"https://doi.org/10.1088/1004-423X/8/12/002","url":null,"abstract":"In this paper, with the aid of Lax pairs, a new Backlund transformation for the variable coefficient KdV equation is found. Based on the Backlund transformation, only if integration is needed, a series of exact solutions can be obtained. This method is important for finding more new and physical-signficant solutions.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122704707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-12-01DOI: 10.1088/1004-423X/8/12/003
Luo Xiao－shu, Fang Jin-qing, Wang Li-hu, Kong Ling-jiang, Jiang Feng
Based on a general principle of physics that a physical system is in the most stable state if it is of the lowest energy state, a new method for chaos control is proposed. A calculable generalized energy function in a nonlinear system is suggested for measuring control process. The Henon map and Lorenz system are taken as two typical examples to demonstrate the method. A series of stabilized periodic orbits as well as inverse sequence of chaotic bands are obtained. At the same time, a unified mechanism of physics for several kinds of current chaos control methods is studied using the idea proposed in this paper.
{"title":"A NEW STRATEGY OF CHAOS CONTROL AND A UNIFIED MECHANISM FOR SEVERAL KINDS OF CHAOS CONTROL METHODS","authors":"Luo Xiao－shu, Fang Jin-qing, Wang Li-hu, Kong Ling-jiang, Jiang Feng","doi":"10.1088/1004-423X/8/12/003","DOIUrl":"https://doi.org/10.1088/1004-423X/8/12/003","url":null,"abstract":"Based on a general principle of physics that a physical system is in the most stable state if it is of the lowest energy state, a new method for chaos control is proposed. A calculable generalized energy function in a nonlinear system is suggested for measuring control process. The Henon map and Lorenz system are taken as two typical examples to demonstrate the method. A series of stabilized periodic orbits as well as inverse sequence of chaotic bands are obtained. At the same time, a unified mechanism of physics for several kinds of current chaos control methods is studied using the idea proposed in this paper.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123919713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-12-01DOI: 10.1088/1004-423X/8/12/010
Dong Guang-jiong, H. Rushan, Huang Yun, K. Sakatani, Zhuang Feng-yuan
Using the transport theory to describe the near infrared light propagating in tissue with finite parallel-plane geometry, and taking the zero-boundary condition, we obtain the analytical expression of average photon density and Green's function incorporating the boundary effects in the homogeneous tissure. Making use of perturbation theory we also obtain the analytical expression of scattered wave induced by the heterogeneity, and present the 2-dimensional spatial transform of scattered wave with respect to transverse coordinate. If the information of heterogeneity on depth and thickness is available, diffraction tomography formula is presented to save the time of image reconstruction; if the information is unknown, we suggest to obtain the inhomogeneous function from the one-dimensional integral equation of 2-dimensional spatial transform of scattered wave applying the direct matrix method or iterative method for image reconstruction. This approach avoids directly solving three-dimensional integral equation of scattered wave. In our proposed approach the strong points of the direct matrix method, iterative method, and diffraction tomography are fully combined.
{"title":"Tomography formula for biochemical imaging of thin tissue with diffuse-photon density waves","authors":"Dong Guang-jiong, H. Rushan, Huang Yun, K. Sakatani, Zhuang Feng-yuan","doi":"10.1088/1004-423X/8/12/010","DOIUrl":"https://doi.org/10.1088/1004-423X/8/12/010","url":null,"abstract":"Using the transport theory to describe the near infrared light propagating in tissue with finite parallel-plane geometry, and taking the zero-boundary condition, we obtain the analytical expression of average photon density and Green's function incorporating the boundary effects in the homogeneous tissure. Making use of perturbation theory we also obtain the analytical expression of scattered wave induced by the heterogeneity, and present the 2-dimensional spatial transform of scattered wave with respect to transverse coordinate. If the information of heterogeneity on depth and thickness is available, diffraction tomography formula is presented to save the time of image reconstruction; if the information is unknown, we suggest to obtain the inhomogeneous function from the one-dimensional integral equation of 2-dimensional spatial transform of scattered wave applying the direct matrix method or iterative method for image reconstruction. This approach avoids directly solving three-dimensional integral equation of scattered wave. In our proposed approach the strong points of the direct matrix method, iterative method, and diffraction tomography are fully combined.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123335555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-12-01DOI: 10.1088/1004-423X/8/12/004
C. Zhaoyang, Zhang Jing-Tao, Xu Zhi-zhan
We discuss the optical bistable behavior of a system of N V-type three-level atoms pumped by a coherent input field and coupled to a squeezed vacuum field by treating the optical bistability of such a system as an input-output problem. It is shown that bistability can be realized due to the squeezed vacuum input.
{"title":"Optical bistability in V medium by squeezed vacuum input","authors":"C. Zhaoyang, Zhang Jing-Tao, Xu Zhi-zhan","doi":"10.1088/1004-423X/8/12/004","DOIUrl":"https://doi.org/10.1088/1004-423X/8/12/004","url":null,"abstract":"We discuss the optical bistable behavior of a system of N V-type three-level atoms pumped by a coherent input field and coupled to a squeezed vacuum field by treating the optical bistability of such a system as an input-output problem. It is shown that bistability can be realized due to the squeezed vacuum input.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130627677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-12-01DOI: 10.1088/1004-423X/8/12/007
Wang Jun-zhong, Li Bo-zang, Gao Jun-shan
Based on the nearly free-electron approximation, we have investigaed the temperature (T) dependence of spin-polarized tunneling in the magnetic tunnel junction with an asymmetrical barrier, with emphasis on the variation of molecular field with T in the same way as that of surface magnetization. It is found that the Slonczewski model can describe well the T dependence of spin-polarized tunneling, while the Julliere model only describes the T dependence of JMR qualitatively, but does accurately that of the difference of tunneling conductance between the parallel and antiparallel alignments for the magnetizations of FMs; Differing from the previous finding, we find the electron spin polarization is not strictly proportional to the surface magnetization, for the former decreases with the increasing T more rapidly than the latter does.
{"title":"Contribution from moldcular field to the temperature dependence of tunneling magnetoresistance","authors":"Wang Jun-zhong, Li Bo-zang, Gao Jun-shan","doi":"10.1088/1004-423X/8/12/007","DOIUrl":"https://doi.org/10.1088/1004-423X/8/12/007","url":null,"abstract":"Based on the nearly free-electron approximation, we have investigaed the temperature (T) dependence of spin-polarized tunneling in the magnetic tunnel junction with an asymmetrical barrier, with emphasis on the variation of molecular field with T in the same way as that of surface magnetization. It is found that the Slonczewski model can describe well the T dependence of spin-polarized tunneling, while the Julliere model only describes the T dependence of JMR qualitatively, but does accurately that of the difference of tunneling conductance between the parallel and antiparallel alignments for the magnetizations of FMs; Differing from the previous finding, we find the electron spin polarization is not strictly proportional to the surface magnetization, for the former decreases with the increasing T more rapidly than the latter does.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123972560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-12-01DOI: 10.1088/1004-423X/8/12/006
Z. Tang, Jian-lun Yang, Shu-huai Wen, Gen-xing Wang, Yu-zhi Guo, Hong-qiong Yang, Ma Chi
A current-mode neutron time-of-flight(nTOF) energy spectrometer for inertial confinement fusion(ICF) ion temperature measurements has been designed which will reduce measuring error of fusion neutron energy spectra when the neutron yield is low. The spectrometer consists of a shallow cup-shaped ST1422 fast plastic scintillator with a thickness of 3 mm and full effective volume of 104 cm3, a microchannel plate photomultiplier tube(MCP-PMT), a piece of coaxial cable(SUJ-50-7) with a length of 20 m, and a transient oscilloscope with a bandwidth of 7 GHz. The main performances of the spectrometer and its components have been calibrated. The rise-time and FWHM of the temporal response function are 260 ps and 850 ps, respectively. This spectrometer will be used to measure ion temperature in the direct-driven implosion experiments on Sheng-Guang 2 laser facility at Shanghai Institute of Optics and Fine Mechanics(SIOFM) next year.
{"title":"Neutron time of flight energy spectrometer for ICF ion temperature diagnostic","authors":"Z. Tang, Jian-lun Yang, Shu-huai Wen, Gen-xing Wang, Yu-zhi Guo, Hong-qiong Yang, Ma Chi","doi":"10.1088/1004-423X/8/12/006","DOIUrl":"https://doi.org/10.1088/1004-423X/8/12/006","url":null,"abstract":"A current-mode neutron time-of-flight(nTOF) energy spectrometer for inertial confinement fusion(ICF) ion temperature measurements has been designed which will reduce measuring error of fusion neutron energy spectra when the neutron yield is low. The spectrometer consists of a shallow cup-shaped ST1422 fast plastic scintillator with a thickness of 3 mm and full effective volume of 104 cm3, a microchannel plate photomultiplier tube(MCP-PMT), a piece of coaxial cable(SUJ-50-7) with a length of 20 m, and a transient oscilloscope with a bandwidth of 7 GHz. The main performances of the spectrometer and its components have been calibrated. The rise-time and FWHM of the temporal response function are 260 ps and 850 ps, respectively. This spectrometer will be used to measure ion temperature in the direct-driven implosion experiments on Sheng-Guang 2 laser facility at Shanghai Institute of Optics and Fine Mechanics(SIOFM) next year.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133863264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-11-01DOI: 10.1088/1004-423X/8/11/010
A. A. Essa, Xu Ke-xi, Zhou Shi-ping, Bao Jia-shan
Microwave responses of YBa2Cu3O7-δ (YBCO) granular film have been studied at the microwave frequency of 30.5 GHz. In the absence of a magnetic field the dependence of a normal microwave response on the bias current is observed at a temperature close to Tc. When a magnetic field ranged from 5.0 mT to 33.0 mT is applied, the responses broaden and shift toward a lower temperature. In the superconducting state, the responses were found to be highly dependent on the magnetic field. For the current equal to 5.0 mA and a magnetic field above 17.0 mT the response increases and did not vanish even at a very low temperature, the fact is believed to be correlated to the anisotropic character of the structure.
{"title":"NON-EQUILIBRIUM MICROWAVE RESPONSE OF Yba 2 Cu 3 O 7-δ GRANULAR THIN FILMS UNDER MAGNETIC FIELDS","authors":"A. A. Essa, Xu Ke-xi, Zhou Shi-ping, Bao Jia-shan","doi":"10.1088/1004-423X/8/11/010","DOIUrl":"https://doi.org/10.1088/1004-423X/8/11/010","url":null,"abstract":"Microwave responses of YBa2Cu3O7-δ (YBCO) granular film have been studied at the microwave frequency of 30.5 GHz. In the absence of a magnetic field the dependence of a normal microwave response on the bias current is observed at a temperature close to Tc. When a magnetic field ranged from 5.0 mT to 33.0 mT is applied, the responses broaden and shift toward a lower temperature. In the superconducting state, the responses were found to be highly dependent on the magnetic field. For the current equal to 5.0 mA and a magnetic field above 17.0 mT the response increases and did not vanish even at a very low temperature, the fact is believed to be correlated to the anisotropic character of the structure.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128513941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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