Based on the historical records in Guangdong Province during the last 500a, the moist index sequence was reconstructed and analyzed by the correlation analysis, wavelet analysis and the power spcctrum analysis. The re...Based on the historical records in Guangdong Province during the last 500a, the moist index sequence was reconstructed and analyzed by the correlation analysis, wavelet analysis and the power spcctrum analysis. The resuits indicate that: 1 ) The El Nino events have evident correlations with the droughts happened in the west and north of Guangdong Province, which intensified the dryness and wetness distribution patterns in these areas in a certain degree. 2) Good correspondence relations exist among the moist index sequence, Greenland ice core oxygen isotope record and the winter-half-year temperature sequence in the eastern China, which showed pattern of moisture and temperature. 3) By applying the wavelet analysis to deal with icities are revealed, among which some can be attributed to the solar activities. At monsoon (especially the East Asian monsoon) activity and the human activity may an apparent monsoonal disposal the data, several apparent period. the same tithe, the ENSO event, also have some influences on the periodicities of the climatic changes in Guangdong Province. 4) Guangdong will persist in dry period before 2040 (±5 years) though some little waterlogged period will also exist in this interval, and after that great floods maybe take place in Guangdong. We think that the variety range of the dryness and wetness has increasing tendency in Guangdong Province in future several even hundred years.展开更多
Based on temperature data in Guangdong in the past 50years, statistical methods are used to analyze the characteristics of temperature in spatial and temporal variation. The results show that land surface temperature ...Based on temperature data in Guangdong in the past 50years, statistical methods are used to analyze the characteristics of temperature in spatial and temporal variation. The results show that land surface temperature warms by 0.16℃/1 0a in Guangdong. The range of warming was lower than the average of nationwide and global land surface. Furthermore, the temperature has a larger increase tendency in winter and spring and coastal areas than in summer and autumn and inland areas. Climate zones move towards the north obviously. North tropical zone is expanding, south subtropical zone is reducing and central subtropical zone is relatively stable. Under the global climate warming, characteristics of climate warming in Guangdong were influenced by atmosphere general circulation, sea surface temperature and human activities etc.展开更多
This study focused on the quantitative evaluation of the impact of the spatio-temporal scale used in data collection and grouping on the standardization of CPUE(catch per unit effort).We used the Chinese squid-jigging...This study focused on the quantitative evaluation of the impact of the spatio-temporal scale used in data collection and grouping on the standardization of CPUE(catch per unit effort).We used the Chinese squid-jigging fishery in the northwestern Pacific Ocean as an example to evaluate 24 scenarios at different spatio-temporal scales,with a combination of four levels of temporal scale(weekly,biweekly,monthly,and bimonthly)and six levels of spatial scale(longitude×latitude:0.5°×0.5°,0.5°×1°,0.5°×2°,1°×0.5°,1°×1°,and 1°×2°).We applied generalized additive models and generalized linear models to analyze the24 scenarios for CPUE standardization,and then the differences in the standardized CPUE among these scenarios were quantified.This study shows that combinations of different spatial and temporal scales could have different impacts on the standardization of CPUE.However,at a fine temporal scale(weekly)different spatial scales yielded similar results for standardized CPUE.The choice of spatio-temporal scale used in data collection and analysis may create added uncertainty in fisheries stock assessment and management.To identify a cost-effective spatio-temporal scale for data collection,we recommend a similar study be undertaken to facilitate the design of effective monitoring programs.展开更多
In this paper, we proved that a sequential space has a cs*-regular cs*-network (or a cs*-regular weak base) is metrizable, which generalized related results in [6], [12] and [14].
Calculations have been performed to investigate the pressure-induced solid-solid phase transitions and the mechanical stability for three zinc-blende II-VI semiconductor compounds: ZnS, ZnSe, ZnTe by ab initio plane-...Calculations have been performed to investigate the pressure-induced solid-solid phase transitions and the mechanical stability for three zinc-blende II-VI semiconductor compounds: ZnS, ZnSe, ZnTe by ab initio plane-wave pseudopotential density functional theory (DFT). Using the generalized gradient approximation (GGA) for exchange and correlation in the scheme of Perdew-Wang 1991 (P Wgl ), the ground state properties and equation of state are obtained, which are well consistent with the experimental data available and other calculations. On the basis of the forth-order Birch-Murnaghan equation of states, the transition pressures Pt are determined through the analysis of enthalpy variation with pressure. A linear-response approach is used to calculate the frequencies of the phonon dispersion. Finally, by the calculations of phonon frequencies, some thermodynamic properties such as the vibrational contribution to the Helmholtz free energy (F), enthedpy (H), entropy (S), and the heat capacity (Cv ) are also successfully obtained.展开更多
Community Radio is a medium which the different threads mingle together brings different social threads together and weaves a vibrant fabric where all without compromising their original composition. Freedom of speech...Community Radio is a medium which the different threads mingle together brings different social threads together and weaves a vibrant fabric where all without compromising their original composition. Freedom of speech and expression is the cornerstone of this medium. In India, Community Radio started its journey in 2004, with the purpose of bringing different sections of the society together so that they can share their experiences, fears, and ambition. Social intervention has been one of the primary agenda Community Radio. Through various awareness-raising programs, it aims to bring positive social change in the lives of people residing around its transmission zone. It also aims to include different sub-sections of its community who are often excluded from the mainstream media.展开更多
A modified evolution model of self-organized criticality on generalized Barabasi-Albert (GBA).scale-free networks is investigated. In our model, we find that spatial and temporal correlations exhibit critical behavi...A modified evolution model of self-organized criticality on generalized Barabasi-Albert (GBA).scale-free networks is investigated. In our model, we find that spatial and temporal correlations exhibit critical behaviors. More importantly, these critical behaviors change with the parameter b, which weights the distance in comparison with the degree in the GBA network evolution.展开更多
The electronic structure, magnetic properties, and optical properties of Co-doped AIN are investigated based upon the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional the...The electronic structure, magnetic properties, and optical properties of Co-doped AIN are investigated based upon the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional theory. The band gaps narrowing of AI1-x Cox N are found with the increase of Co concentrations. The analyses of the band structures and density of states show that AI1-xCoxN alloys exhibit a halfometallie character. Moreover, we have succeeded in demonstrating that Co doped AIN system in x = 0.125 is always antiferromagnetie, which is in good agreement with the experimental results. Besides, it is shown that the insertion of Co atom leads to redshift of the optical absorption edge. Finally, the optical constants of pure A1N and AI1-xCoxN alloy, such as loss function, refractive index and reflectivity, are discussed.展开更多
An important research topic for prospecting seismology is to provide a fast accurate velocity model from pre-stack depth migration. Aiming at such a problem, we propose a quadratic precision generalized nonlinear glob...An important research topic for prospecting seismology is to provide a fast accurate velocity model from pre-stack depth migration. Aiming at such a problem, we propose a quadratic precision generalized nonlinear global optimization migration velocity inversion. First we discard the assumption that there is a linear relationship between residual depth and residual velocity and propose a velocity model correction equation with quadratic precision which enables the velocity model from each iteration to approach the real model as quickly as possible. Second, we use a generalized nonlinear inversion to get the global optimal velocity perturbation model to all traces. This method can expedite the convergence speed and also can decrease the probability of falling into a local minimum during inversion. The synthetic data and Mamlousi data examples show that our method has a higher precision and needs only a few iterations and consequently enhances the practicability and accuracy of migration velocity analysis (MVA) in complex areas.展开更多
The effects of roughness geometries and relative roughness height at the slip flow regime to investigate the thermal and hydraulic performances of microchannel have been considered in the present article using a therm...The effects of roughness geometries and relative roughness height at the slip flow regime to investigate the thermal and hydraulic performances of microchannel have been considered in the present article using a thermal Lattice Boltzmann Method(TLBM).A two dimensional 9-bit(D2Q9)single relaxation time(SRT)model is used to simulate this problem.In micro-flows,the local density variation is still relatively small,but the total density changes,therefore,in order to account this density variation and its effect on the kinematic viscosityν,a new relaxation time proposed by Niu et al.[13]is used.The roughness geometry is modeled as a series of square and circular riblets with a relative roughness height from 0%to 10%of the channel height.The friction coefficients in terms of Poiseuille number(Pn)and the dimensionless heat transfer rate in terms of Nusselt number(Nu)have been discussed in order to analyze the roughness effects.The thermal-hydraulic performance(η)is calculated considering the simultaneous effects of thermal and fluid friction(pressure drop)at the slip flow regime at Knudsen number,Kn,ranging from 0.01 to 0.10 with other controlling parameters for both kind of geometries.The results have been compared with previous published works and it is found to be in very good agreement.展开更多
The numerical method for multi-dimensional integrals is of great importance, particularly in the uncertainty quantification of engineering structures. The key is to generate representative points as few as possible bu...The numerical method for multi-dimensional integrals is of great importance, particularly in the uncertainty quantification of engineering structures. The key is to generate representative points as few as possible but of acceptable accuracy. A generalized L2(GL2)-discrepancy is studied by taking unequal weights for the point set. The extended Koksma-Hlawka inequality is discussed. Thereby, a worst-case error estimate is provided by such defined GL2-discrepancy, whose dosed-form expression is available. The characteristic values of GL2-discrepancy are investigated. An optimal strategy for the selection of the representative point sets with a prescribed cardinal number is proposed by minimizing the GL2-discrepancy. The three typical examples of the multi-dimensional integrals are investigated. The stochastic dynamic response analysis of a nonlinear structure is then studied by incorporating the proposed method into the probability density evolution method. It is shown that the proposed method is advantageous in achieving tradeoffs between the efficiency and accuracy of the exemplified problems. Problems to be further studied are discussed.展开更多
In this article, we apply the Generalized Uncertainty Principle (GUP), which is consistent with quantum gravity theories to an elementary particle in a finite potential well, and study the quantum behavior in this s...In this article, we apply the Generalized Uncertainty Principle (GUP), which is consistent with quantum gravity theories to an elementary particle in a finite potential well, and study the quantum behavior in this system. The generalized Hamiltonian contains two additional terms, which are proportional to ap3 (the result of the maximum momentum assumption) and a2p4 (the result of the minimum length assumption), where a - 1/MpIc is the GUP parameter. On the basis of the work by Ali et al., we solve the generaiized Schrodinger equation which is extended to include the a2 correction term, and find that the length L of the finite potentiai well must be quantized. Then a generalization to the double-square-well potential is discussed. The result shows that all the measurable lengths especially the distance between the two potential wells are quantized in units of aolp1 in GUP scenario.展开更多
基金Under the auspices of the Natural Science Foundation of Guang dong Province(No.031522),the Fok Ying Tung Ed-ucation Foundation(No.91021)
文摘Based on the historical records in Guangdong Province during the last 500a, the moist index sequence was reconstructed and analyzed by the correlation analysis, wavelet analysis and the power spcctrum analysis. The resuits indicate that: 1 ) The El Nino events have evident correlations with the droughts happened in the west and north of Guangdong Province, which intensified the dryness and wetness distribution patterns in these areas in a certain degree. 2) Good correspondence relations exist among the moist index sequence, Greenland ice core oxygen isotope record and the winter-half-year temperature sequence in the eastern China, which showed pattern of moisture and temperature. 3) By applying the wavelet analysis to deal with icities are revealed, among which some can be attributed to the solar activities. At monsoon (especially the East Asian monsoon) activity and the human activity may an apparent monsoonal disposal the data, several apparent period. the same tithe, the ENSO event, also have some influences on the periodicities of the climatic changes in Guangdong Province. 4) Guangdong will persist in dry period before 2040 (±5 years) though some little waterlogged period will also exist in this interval, and after that great floods maybe take place in Guangdong. We think that the variety range of the dryness and wetness has increasing tendency in Guangdong Province in future several even hundred years.
基金Key project from Natural Science Foundation of China (40231009)
文摘Based on temperature data in Guangdong in the past 50years, statistical methods are used to analyze the characteristics of temperature in spatial and temporal variation. The results show that land surface temperature warms by 0.16℃/1 0a in Guangdong. The range of warming was lower than the average of nationwide and global land surface. Furthermore, the temperature has a larger increase tendency in winter and spring and coastal areas than in summer and autumn and inland areas. Climate zones move towards the north obviously. North tropical zone is expanding, south subtropical zone is reducing and central subtropical zone is relatively stable. Under the global climate warming, characteristics of climate warming in Guangdong were influenced by atmosphere general circulation, sea surface temperature and human activities etc.
基金Supported by Shanghai Universities First-class Disciplines Project,Discipline name:Fisheries(A),the National Natural Science Foundation of China(No.NSFC41276156)the National High Technology Research and Development Program of China(863 Program)(No.2012AA092303)+1 种基金the Shanghai Science and Technology Innovation Program(No.12231203900)CHEN Yong’s involvement was supported by the Shanghai Ocean University
文摘This study focused on the quantitative evaluation of the impact of the spatio-temporal scale used in data collection and grouping on the standardization of CPUE(catch per unit effort).We used the Chinese squid-jigging fishery in the northwestern Pacific Ocean as an example to evaluate 24 scenarios at different spatio-temporal scales,with a combination of four levels of temporal scale(weekly,biweekly,monthly,and bimonthly)and six levels of spatial scale(longitude×latitude:0.5°×0.5°,0.5°×1°,0.5°×2°,1°×0.5°,1°×1°,and 1°×2°).We applied generalized additive models and generalized linear models to analyze the24 scenarios for CPUE standardization,and then the differences in the standardized CPUE among these scenarios were quantified.This study shows that combinations of different spatial and temporal scales could have different impacts on the standardization of CPUE.However,at a fine temporal scale(weekly)different spatial scales yielded similar results for standardized CPUE.The choice of spatio-temporal scale used in data collection and analysis may create added uncertainty in fisheries stock assessment and management.To identify a cost-effective spatio-temporal scale for data collection,we recommend a similar study be undertaken to facilitate the design of effective monitoring programs.
基金Supported by the NNSF of China(10571151,10671173)Supported by the NSF of Fujian Province(2006J0228,2008F5066)
文摘In this paper, we proved that a sequential space has a cs*-regular cs*-network (or a cs*-regular weak base) is metrizable, which generalized related results in [6], [12] and [14].
基金Support by the National Natural Science Foundation of China under Grant No.10776022the National Key Laboratory Fund for Shock Wave and Detonation Physics Research of the China Academy of Engineering Physics and the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No.20090181110080
文摘Calculations have been performed to investigate the pressure-induced solid-solid phase transitions and the mechanical stability for three zinc-blende II-VI semiconductor compounds: ZnS, ZnSe, ZnTe by ab initio plane-wave pseudopotential density functional theory (DFT). Using the generalized gradient approximation (GGA) for exchange and correlation in the scheme of Perdew-Wang 1991 (P Wgl ), the ground state properties and equation of state are obtained, which are well consistent with the experimental data available and other calculations. On the basis of the forth-order Birch-Murnaghan equation of states, the transition pressures Pt are determined through the analysis of enthalpy variation with pressure. A linear-response approach is used to calculate the frequencies of the phonon dispersion. Finally, by the calculations of phonon frequencies, some thermodynamic properties such as the vibrational contribution to the Helmholtz free energy (F), enthedpy (H), entropy (S), and the heat capacity (Cv ) are also successfully obtained.
文摘Community Radio is a medium which the different threads mingle together brings different social threads together and weaves a vibrant fabric where all without compromising their original composition. Freedom of speech and expression is the cornerstone of this medium. In India, Community Radio started its journey in 2004, with the purpose of bringing different sections of the society together so that they can share their experiences, fears, and ambition. Social intervention has been one of the primary agenda Community Radio. Through various awareness-raising programs, it aims to bring positive social change in the lives of people residing around its transmission zone. It also aims to include different sub-sections of its community who are often excluded from the mainstream media.
基金The project supported by National Natural Science Foundation of China under Grant No. 90203008 and the Doctoral Foundation of Ministry of Education of China
文摘A modified evolution model of self-organized criticality on generalized Barabasi-Albert (GBA).scale-free networks is investigated. In our model, we find that spatial and temporal correlations exhibit critical behaviors. More importantly, these critical behaviors change with the parameter b, which weights the distance in comparison with the degree in the GBA network evolution.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant Nos.BUPT2009RC0412 and 10979065the National High Technology Research and Development Program of China under Grant No.2009AA03Z405the National Natural Science Foundation of China under Grant Nos.60644004 and 10979065
文摘The electronic structure, magnetic properties, and optical properties of Co-doped AIN are investigated based upon the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional theory. The band gaps narrowing of AI1-x Cox N are found with the increase of Co concentrations. The analyses of the band structures and density of states show that AI1-xCoxN alloys exhibit a halfometallie character. Moreover, we have succeeded in demonstrating that Co doped AIN system in x = 0.125 is always antiferromagnetie, which is in good agreement with the experimental results. Besides, it is shown that the insertion of Co atom leads to redshift of the optical absorption edge. Finally, the optical constants of pure A1N and AI1-xCoxN alloy, such as loss function, refractive index and reflectivity, are discussed.
基金This work is supported by National Natural Science Foundation of China (Grant No.40839905).
文摘An important research topic for prospecting seismology is to provide a fast accurate velocity model from pre-stack depth migration. Aiming at such a problem, we propose a quadratic precision generalized nonlinear global optimization migration velocity inversion. First we discard the assumption that there is a linear relationship between residual depth and residual velocity and propose a velocity model correction equation with quadratic precision which enables the velocity model from each iteration to approach the real model as quickly as possible. Second, we use a generalized nonlinear inversion to get the global optimal velocity perturbation model to all traces. This method can expedite the convergence speed and also can decrease the probability of falling into a local minimum during inversion. The synthetic data and Mamlousi data examples show that our method has a higher precision and needs only a few iterations and consequently enhances the practicability and accuracy of migration velocity analysis (MVA) in complex areas.
文摘The effects of roughness geometries and relative roughness height at the slip flow regime to investigate the thermal and hydraulic performances of microchannel have been considered in the present article using a thermal Lattice Boltzmann Method(TLBM).A two dimensional 9-bit(D2Q9)single relaxation time(SRT)model is used to simulate this problem.In micro-flows,the local density variation is still relatively small,but the total density changes,therefore,in order to account this density variation and its effect on the kinematic viscosityν,a new relaxation time proposed by Niu et al.[13]is used.The roughness geometry is modeled as a series of square and circular riblets with a relative roughness height from 0%to 10%of the channel height.The friction coefficients in terms of Poiseuille number(Pn)and the dimensionless heat transfer rate in terms of Nusselt number(Nu)have been discussed in order to analyze the roughness effects.The thermal-hydraulic performance(η)is calculated considering the simultaneous effects of thermal and fluid friction(pressure drop)at the slip flow regime at Knudsen number,Kn,ranging from 0.01 to 0.10 with other controlling parameters for both kind of geometries.The results have been compared with previous published works and it is found to be in very good agreement.
基金supported by the National Natural Science Foundation of China(Grant Nos.51538010&51261120374)the State Key Laboratory of Disaster Reduction in Civil Engineering(Grant No.SLDRCE14-B-17)the Fundamental Funding for Central Universities
文摘The numerical method for multi-dimensional integrals is of great importance, particularly in the uncertainty quantification of engineering structures. The key is to generate representative points as few as possible but of acceptable accuracy. A generalized L2(GL2)-discrepancy is studied by taking unequal weights for the point set. The extended Koksma-Hlawka inequality is discussed. Thereby, a worst-case error estimate is provided by such defined GL2-discrepancy, whose dosed-form expression is available. The characteristic values of GL2-discrepancy are investigated. An optimal strategy for the selection of the representative point sets with a prescribed cardinal number is proposed by minimizing the GL2-discrepancy. The three typical examples of the multi-dimensional integrals are investigated. The stochastic dynamic response analysis of a nonlinear structure is then studied by incorporating the proposed method into the probability density evolution method. It is shown that the proposed method is advantageous in achieving tradeoffs between the efficiency and accuracy of the exemplified problems. Problems to be further studied are discussed.
基金Supported by National Natural Science Foundation of China under Grant Nos.10865003 and 11464005
文摘In this article, we apply the Generalized Uncertainty Principle (GUP), which is consistent with quantum gravity theories to an elementary particle in a finite potential well, and study the quantum behavior in this system. The generalized Hamiltonian contains two additional terms, which are proportional to ap3 (the result of the maximum momentum assumption) and a2p4 (the result of the minimum length assumption), where a - 1/MpIc is the GUP parameter. On the basis of the work by Ali et al., we solve the generaiized Schrodinger equation which is extended to include the a2 correction term, and find that the length L of the finite potentiai well must be quantized. Then a generalization to the double-square-well potential is discussed. The result shows that all the measurable lengths especially the distance between the two potential wells are quantized in units of aolp1 in GUP scenario.