Pub Date : 1999-11-01DOI: 10.1088/1004-423X/8/11/002
Mei Dong-cheng, Chen Luo-en, Xie Guang-zhong, Cao Li, Wu Da–jin
The transition rate of a double well system driven by cross-correlated noises has been investigated, in when the correlation times between the noises are nonzero. From numerical computation, we find followings: (1) The transition rate decreases as the lambda (lambda is the strength of the correlations between noises) increases. (2) The transition rate increases as the tau (tau is the correlation time between noises) increases. It imglies that tau and lambda play opposite roles in the transition rate of the system (3). For the case of perfectly correlated noises (lambda = 1), there is no the suppressed phenomenon in the double well system with cross-correlated noise sources.
{"title":"THE TRANSITION RATE OF A DOUBLE WELL SYSTEM DRIVEN BY CROSS-CORRELATED NOISES","authors":"Mei Dong-cheng, Chen Luo-en, Xie Guang-zhong, Cao Li, Wu Da–jin","doi":"10.1088/1004-423X/8/11/002","DOIUrl":"https://doi.org/10.1088/1004-423X/8/11/002","url":null,"abstract":"The transition rate of a double well system driven by cross-correlated noises has been investigated, in when the correlation times between the noises are nonzero. From numerical computation, we find followings: (1) The transition rate decreases as the lambda (lambda is the strength of the correlations between noises) increases. (2) The transition rate increases as the tau (tau is the correlation time between noises) increases. It imglies that tau and lambda play opposite roles in the transition rate of the system (3). For the case of perfectly correlated noises (lambda = 1), there is no the suppressed phenomenon in the double well system with cross-correlated noise sources.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"1 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":"131076662","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/8/11/001
Yang Shi-qing, Zhang Wenxu, Gong Jie, Zhang Wanli, Wang Hao-cai
In order to calculate the pair potentials between light rare-earth metallic atoms with double hexagonal close-packed (dhcp) crystal structure, a Mobius inversion transform formula for the dhcp structure is proposed. The pair potentials for the light rare-earth atoms are calculated by this formula. These pair potentials are fitted to the analytic Morse-type potential expressions.
{"title":"THEORETICAL CALCULATION ON THE PAIR POTENTIALS BETWEEN LIGHT RARE-EARTH METALLIC ATOMS","authors":"Yang Shi-qing, Zhang Wenxu, Gong Jie, Zhang Wanli, Wang Hao-cai","doi":"10.1088/1004-423X/8/11/001","DOIUrl":"https://doi.org/10.1088/1004-423X/8/11/001","url":null,"abstract":"In order to calculate the pair potentials between light rare-earth metallic atoms with double hexagonal close-packed (dhcp) crystal structure, a Mobius inversion transform formula for the dhcp structure is proposed. The pair potentials for the light rare-earth atoms are calculated by this formula. These pair potentials are fitted to the analytic Morse-type potential expressions.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"55 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":"134506353","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/8/11/008
Zhao Guo-nian, Xian-yu Hai-qing, Song Jian, Li Xiao-bai, Ren Shang-yuan
Using a recently developed new scheme, we investigated the electronic structure of the lowest conduction band states of cuboid GaAs quantum dots with different shapes and sizes in a wide range from 4 to 120a (a is the lattice constant). The critical edge length of the direct/indirect crossover in GaAs cuboid quantum dots depends on the size and shape of the quantum dots. As a deduction we also discussed the critical size of direct/indirect transition in GaAs quantum wires and thin films.
{"title":"Size and shape dependence of the lowest conduction band states in GaAs quantum dots","authors":"Zhao Guo-nian, Xian-yu Hai-qing, Song Jian, Li Xiao-bai, Ren Shang-yuan","doi":"10.1088/1004-423X/8/11/008","DOIUrl":"https://doi.org/10.1088/1004-423X/8/11/008","url":null,"abstract":"Using a recently developed new scheme, we investigated the electronic structure of the lowest conduction band states of cuboid GaAs quantum dots with different shapes and sizes in a wide range from 4 to 120a (a is the lattice constant). The critical edge length of the direct/indirect crossover in GaAs cuboid quantum dots depends on the size and shape of the quantum dots. As a deduction we also discussed the critical size of direct/indirect transition in GaAs quantum wires and thin films.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"1 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":"128167579","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/8/11/009
Xu Pengshou, Guo Hong-zhi, Zhang Fapei, Lu Er-Dong, Xu Fa-qiang, Pan Hai-bin, Z. Xinyi
Ferromagnetic resonance (FMR) has been used to investigat the magnetism of Fe overlayer on S-passivated GaAs(100) pretreated by CH3CSNH2. Comparing with the magnetism of Fe overlayer on clean GaAs(100), we find that sulfur passivation can prevent As diffusion into Fe overlayer and weaken the interaction of As and Fe. It results in enhancing the magnetism of Fe overlayer on GaAs(100). We also investigate the effects of the pre-annealing of S- passivated GaAs(100) substrate on the magnetism of Fe overlayers. The results show that the maximum effective magnetization can be obtained at annealing temperature of 400 °C. According to the experimental results of synchrotron radiation photoemission, it can be explained by the change of chemical composition and surface structure of the passivation layer on GaAs(100) surface after the annealing.
{"title":"A NEW METHOD TO ENHANCE THE MAGNETISM OF Fe OVERLAYER ON GaAs(100): SULFUR PASSIVATION USING CH 3 CSNH 2","authors":"Xu Pengshou, Guo Hong-zhi, Zhang Fapei, Lu Er-Dong, Xu Fa-qiang, Pan Hai-bin, Z. Xinyi","doi":"10.1088/1004-423X/8/11/009","DOIUrl":"https://doi.org/10.1088/1004-423X/8/11/009","url":null,"abstract":"Ferromagnetic resonance (FMR) has been used to investigat the magnetism of Fe overlayer on S-passivated GaAs(100) pretreated by CH3CSNH2. Comparing with the magnetism of Fe overlayer on clean GaAs(100), we find that sulfur passivation can prevent As diffusion into Fe overlayer and weaken the interaction of As and Fe. It results in enhancing the magnetism of Fe overlayer on GaAs(100). We also investigate the effects of the pre-annealing of S- passivated GaAs(100) substrate on the magnetism of Fe overlayers. The results show that the maximum effective magnetization can be obtained at annealing temperature of 400 °C. According to the experimental results of synchrotron radiation photoemission, it can be explained by the change of chemical composition and surface structure of the passivation layer on GaAs(100) surface after the annealing.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"65 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":"133027809","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/8/11/004
Luo Cheng-lin, Zhou Yan-huai
A transferable tight-binding potential for nickel was used with molecular-dynamics methods and simulated-annealing techniques to study the structural properties of nickel clusters Nin (n ≤ 55). The mean coordination number and structure of some clusters and their relative stability have been obtained.
{"title":"A NEW APPROACH TO STRUCTURES OF NICKEL CLUSTERS","authors":"Luo Cheng-lin, Zhou Yan-huai","doi":"10.1088/1004-423X/8/11/004","DOIUrl":"https://doi.org/10.1088/1004-423X/8/11/004","url":null,"abstract":"A transferable tight-binding potential for nickel was used with molecular-dynamics methods and simulated-annealing techniques to study the structural properties of nickel clusters Nin (n ≤ 55). The mean coordination number and structure of some clusters and their relative stability have been obtained.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"3 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":"134534925","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}
The time-domain ABCD matrix formalism is based on the propagation of a Gaussian pulse which is characterized by the pulsewidth and chirp. In this paper, the time-domain ABCD matrix of the SPM (self phase modulation) is perfected so as to acquire more information. With the time-domain ABCD matrices of amplitude modulation, filtration from the optical bandpass, group velocity dispersion and SPM, the detailed characteristics of actively mode-locked fiber laser are described and the steady-state solutions are derived for two simple cases. The application of the formalism is also helpful to understand the mechanism of mode-locking in an actively mode-locked fiber laser.
{"title":"Novel analytic theory for actively mode-locked fiber laser","authors":"Chang Guo-qing, Lou Cai-yun, Ling Yuhua, Gao Yizhi","doi":"10.1088/1004-423X/8/11/007","DOIUrl":"https://doi.org/10.1088/1004-423X/8/11/007","url":null,"abstract":"The time-domain ABCD matrix formalism is based on the propagation of a Gaussian pulse which is characterized by the pulsewidth and chirp. In this paper, the time-domain ABCD matrix of the SPM (self phase modulation) is perfected so as to acquire more information. With the time-domain ABCD matrices of amplitude modulation, filtration from the optical bandpass, group velocity dispersion and SPM, the detailed characteristics of actively mode-locked fiber laser are described and the steady-state solutions are derived for two simple cases. The application of the formalism is also helpful to understand the mechanism of mode-locking in an actively mode-locked fiber laser.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"23 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":"130993401","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/8/11/006
Shi Wei, Fang Changshui, Pan Qi-wei, Sun Xun, Gu Qing-tian, Xu Dong
chielectric relaxation theory was demonstrated. chielectric relaxation that selectively probes chromophore reorientation in the frequency domain was described by the Havriliak Negami (HN) function. chielectric spectra of several nonlinear optical (NLO) polymers were fitted well by the HN function. To describe the scaling of chromophore reorientation relaxation in frequency domain, two-shape parameters m and n describing the low- and high- frequency wings of the chielectric spectra need to be specified, besides the chielectric characteristic relaxation time τ and the chielectric strength Δχ(2). From the temperature dependences of m and n of NLO polymers, the relations between the chromophore relaxation and the α relaxation of the polymer host have been revealed.
{"title":"Modeling and scaling of chielectric relaxation of nonlinear optical polymers in frequency domain","authors":"Shi Wei, Fang Changshui, Pan Qi-wei, Sun Xun, Gu Qing-tian, Xu Dong","doi":"10.1088/1004-423X/8/11/006","DOIUrl":"https://doi.org/10.1088/1004-423X/8/11/006","url":null,"abstract":"chielectric relaxation theory was demonstrated. chielectric relaxation that selectively probes chromophore reorientation in the frequency domain was described by the Havriliak Negami (HN) function. chielectric spectra of several nonlinear optical (NLO) polymers were fitted well by the HN function. To describe the scaling of chromophore reorientation relaxation in frequency domain, two-shape parameters m and n describing the low- and high- frequency wings of the chielectric spectra need to be specified, besides the chielectric characteristic relaxation time τ and the chielectric strength Δχ(2). From the temperature dependences of m and n of NLO polymers, the relations between the chromophore relaxation and the α relaxation of the polymer host have been revealed.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"9 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":"121536342","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/8/11/003
Jiang Dongdong, Wu Bo-qun, Zhu Jing, L. Lu
In this work, double-center-doped luminescent material CaS:Bi3+, Eu2+ was made via flux NH4Cl by sintering in excess sulfur environment. The sample had a purplish red net luminescent color. Excitation spectra at both red, 650 nm and blue, 487 nm were taken. The red emission from Eu2+ center was mainly come from the 4f65d1 absorption in the CaS host. The blue emission from the Bi3+ center on the other hand showed no big difference from the singly doped CaS:Bi3+ materials in excitation spectrum. Emission spectra were obtained at excitaton of 270 nm and 300 nm. Stokes shift was moved about 20-30 nm, under different point excitation. Emission peaks of both Bi3+ and Eu2+ centers appeared at 463 nm, 642.5 nm by 270 nm excitation and 487 nm, 620 nm by 300 nm excitation respectively. After-glow decay curves were also obtained and the shapes of decay curves are similar and it is due to the single hole-trap system by lattice defects.
{"title":"LUMINESCENCE OF Bi 3+ and Eu 2+ DOUBLE CENTERS DOPED IN CaS HOST","authors":"Jiang Dongdong, Wu Bo-qun, Zhu Jing, L. Lu","doi":"10.1088/1004-423X/8/11/003","DOIUrl":"https://doi.org/10.1088/1004-423X/8/11/003","url":null,"abstract":"In this work, double-center-doped luminescent material CaS:Bi3+, Eu2+ was made via flux NH4Cl by sintering in excess sulfur environment. The sample had a purplish red net luminescent color. Excitation spectra at both red, 650 nm and blue, 487 nm were taken. The red emission from Eu2+ center was mainly come from the 4f65d1 absorption in the CaS host. The blue emission from the Bi3+ center on the other hand showed no big difference from the singly doped CaS:Bi3+ materials in excitation spectrum. Emission spectra were obtained at excitaton of 270 nm and 300 nm. Stokes shift was moved about 20-30 nm, under different point excitation. Emission peaks of both Bi3+ and Eu2+ centers appeared at 463 nm, 642.5 nm by 270 nm excitation and 487 nm, 620 nm by 300 nm excitation respectively. After-glow decay curves were also obtained and the shapes of decay curves are similar and it is due to the single hole-trap system by lattice defects.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"27 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":"125659802","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/8/11/005
Feng Xun-Li, Zhang Qing-hua, Gong Shang-qing, Xu Zhi-zhan
We present a scheme to realize the arbitrary control of the time evolution of an atom-cavity system via atomic feedback for the generation of an arbitrary quantum state. The scheme does not need to detect the atomic state, thus the uncontrollable measurement can be avoided.
{"title":"Generation of arbitrary quantum state via atomic feedback","authors":"Feng Xun-Li, Zhang Qing-hua, Gong Shang-qing, Xu Zhi-zhan","doi":"10.1088/1004-423X/8/11/005","DOIUrl":"https://doi.org/10.1088/1004-423X/8/11/005","url":null,"abstract":"We present a scheme to realize the arbitrary control of the time evolution of an atom-cavity system via atomic feedback for the generation of an arbitrary quantum state. The scheme does not need to detect the atomic state, thus the uncontrollable measurement can be avoided.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"30 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":"132672587","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 : 1999-10-01DOI: 10.1088/1004-423X/8/10/002
Gu Chun-ming, S. Ke
A method of chaos control with optical feedback in a Q switching CO2 laser was proposed and investigated theoretically. The results of the computer simulation show that to control the chaos to the stable states could be realized by adjusting the feedback coefficient or delay-time.
{"title":"Controlling chaos with optical feedback in a Q switching CO2 laser","authors":"Gu Chun-ming, S. Ke","doi":"10.1088/1004-423X/8/10/002","DOIUrl":"https://doi.org/10.1088/1004-423X/8/10/002","url":null,"abstract":"A method of chaos control with optical feedback in a Q switching CO2 laser was proposed and investigated theoretically. The results of the computer simulation show that to control the chaos to the stable states could be realized by adjusting the feedback coefficient or delay-time.","PeriodicalId":188146,"journal":{"name":"Acta Physica Sinica (overseas Edition)","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124059847","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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