The output power of a photovoltaic system largely depends on the amount of solar radiation that can be received by the photovoltaic panel, and the solar radiation energy reaching the ground is affected by the radiatio...The output power of a photovoltaic system largely depends on the amount of solar radiation that can be received by the photovoltaic panel, and the solar radiation energy reaching the ground is affected by the radiation transmission process. However, in engineering practice, numerical simulation prediction schemes tend to adopt a kind of radiation scheme, and the prediction of solar radiation and photovoltaic power cannot always meet the prediction accuracy. In this paper, NCEP-NCAR reanalysis data are used as the initial field, and a variety of radiation parameterization schemes are used to produce simulations for the Xinjiang area. Through analysis of examples, it is found that the simulation results differ greatly depending on the radiation parameterization scheme employed, with the maximum absolute error of the total radiation and the predicted power being 106.67 W m-2 and 3.5 MW, respectively. Meanwhile, the mean absolute percentage error of the total radiation ranges from 8.6% to 17.3%, and that of the predicted power from 11.3% to 20.2%. Having analyzed the simulation results of the different radiation parameterization schemes, we conclude that the RRTM/Dudhia and CAM （Community Atmospheric Model） schemes are the most appropriate when under clear-weather conditions.展开更多
Over the past 20 years, significant progress has been made in virtual plant modeling corresponding to the rapid advances in information technology. Virtual plant research has broad applications in agronomy, forestry, ...Over the past 20 years, significant progress has been made in virtual plant modeling corresponding to the rapid advances in information technology. Virtual plant research has broad applications in agronomy, forestry, ecol- ogy and remote sensing. As many biological processes are driven by light, it is the key for virtual plant to estimate the light absorbed by each organ. This paper presents the radiance equation suitable for calculating sun and sky light intercepted by plant organs based on the principles of the interaction between light and plant canopy firstly; analyzes the process principles of plant canopy primary lighting based on ray casting and projection secondly; describes the multiple scattering of plant lighting based on Monte Carlo ray tracing method and on the radiosity method thirdly; and confirms the research with 3D visualization based on Virtual Reality Modeling Language (VRML) finally. The research is the primary work of digital agriculture, and important for monitoring and estimating corn growth in Northeast China.展开更多
1 INTRODUCTION Cloud radiation is one of the most important and indefinite factors in atmospheric radiation. As shown in a comparative study by Cess et al. with a climate model, differences can be very large in the ou...1 INTRODUCTION Cloud radiation is one of the most important and indefinite factors in atmospheric radiation. As shown in a comparative study by Cess et al. with a climate model, differences can be very large in the outcome of varying schemes of cloud parameterization. It is therefore of great significance to have a relatively accurate scheme of cloud parameterization for the atmospheric radiative transfer process. According to the Mie＇s scattering theory, the scale parameter of the particulate has a very important effect on its optical property. It is then seen that the number concentration and size distribution of cloud droplets play an important in the determination of the optical properties of cloud droplets.展开更多
A scheme is proposed to generate W state of N atoms trapped in a cavity,based on adiabatic passage alongdark state.Taking advantage of adiabatic passage,the atoms have no probability of being excited and thus the atom...A scheme is proposed to generate W state of N atoms trapped in a cavity,based on adiabatic passage alongdark state.Taking advantage of adiabatic passage,the atoms have no probability of being excited and thus the atomicspontaneous emission is suppressed.The scheme is simple.It does not need to adjust the interaction time accurately,anddoes not need to prepare the cavity field in one-photon state.Numerical simulation shows that the successful probabilityof the scheme increases with the increasing of the atom number.展开更多
The combination of photovoltaic system with a thermal to form the hybrid PVT （photovoltaic thermal）, which together will generate electricity and heat. This energy depends on the input that is to say the energy of s...The combination of photovoltaic system with a thermal to form the hybrid PVT （photovoltaic thermal）, which together will generate electricity and heat. This energy depends on the input that is to say the energy of solar radiation, temperature and speed wind and output which is the operating temperature of the system. This production also depends on the mode of heat removal. The authors present in this article; a study by a numerical simulation of the thermal behavior of a prototype hybrid sensor through the development of an energy balance that involves heat exchange between the different components of the hybrid sensor, and it will allow us to study the influence of internal and external parameters on the temperature variation in the different layers of the prototype PV/T studied.展开更多
基金funded by the National Natural Science Foundation of ChinaNational Research Council of Thailand Joint Research Project[grant number 51561145011]a State Grid Corporation of Science and Technology Project[grant number NY71-15-056]
文摘The output power of a photovoltaic system largely depends on the amount of solar radiation that can be received by the photovoltaic panel, and the solar radiation energy reaching the ground is affected by the radiation transmission process. However, in engineering practice, numerical simulation prediction schemes tend to adopt a kind of radiation scheme, and the prediction of solar radiation and photovoltaic power cannot always meet the prediction accuracy. In this paper, NCEP-NCAR reanalysis data are used as the initial field, and a variety of radiation parameterization schemes are used to produce simulations for the Xinjiang area. Through analysis of examples, it is found that the simulation results differ greatly depending on the radiation parameterization scheme employed, with the maximum absolute error of the total radiation and the predicted power being 106.67 W m-2 and 3.5 MW, respectively. Meanwhile, the mean absolute percentage error of the total radiation ranges from 8.6% to 17.3%, and that of the predicted power from 11.3% to 20.2%. Having analyzed the simulation results of the different radiation parameterization schemes, we conclude that the RRTM/Dudhia and CAM （Community Atmospheric Model） schemes are the most appropriate when under clear-weather conditions.
基金Under the auspices of National High-Tech Research and Development Program of China (863 Program) (No. 2006AA10Z227)the "Eleventh Five-year Plan" of Jilin Province Educational Office (No. 2007[456])
文摘Over the past 20 years, significant progress has been made in virtual plant modeling corresponding to the rapid advances in information technology. Virtual plant research has broad applications in agronomy, forestry, ecol- ogy and remote sensing. As many biological processes are driven by light, it is the key for virtual plant to estimate the light absorbed by each organ. This paper presents the radiance equation suitable for calculating sun and sky light intercepted by plant organs based on the principles of the interaction between light and plant canopy firstly; analyzes the process principles of plant canopy primary lighting based on ray casting and projection secondly; describes the multiple scattering of plant lighting based on Monte Carlo ray tracing method and on the radiosity method thirdly; and confirms the research with 3D visualization based on Virtual Reality Modeling Language (VRML) finally. The research is the primary work of digital agriculture, and important for monitoring and estimating corn growth in Northeast China.
文摘1 INTRODUCTION Cloud radiation is one of the most important and indefinite factors in atmospheric radiation. As shown in a comparative study by Cess et al. with a climate model, differences can be very large in the outcome of varying schemes of cloud parameterization. It is therefore of great significance to have a relatively accurate scheme of cloud parameterization for the atmospheric radiative transfer process. According to the Mie＇s scattering theory, the scale parameter of the particulate has a very important effect on its optical property. It is then seen that the number concentration and size distribution of cloud droplets play an important in the determination of the optical properties of cloud droplets.
基金Supported by the Science Foundation of Educational Committee of Fujian Province under Grant No.JB09011
文摘A scheme is proposed to generate W state of N atoms trapped in a cavity,based on adiabatic passage alongdark state.Taking advantage of adiabatic passage,the atoms have no probability of being excited and thus the atomicspontaneous emission is suppressed.The scheme is simple.It does not need to adjust the interaction time accurately,anddoes not need to prepare the cavity field in one-photon state.Numerical simulation shows that the successful probabilityof the scheme increases with the increasing of the atom number.
文摘The combination of photovoltaic system with a thermal to form the hybrid PVT （photovoltaic thermal）, which together will generate electricity and heat. This energy depends on the input that is to say the energy of solar radiation, temperature and speed wind and output which is the operating temperature of the system. This production also depends on the mode of heat removal. The authors present in this article; a study by a numerical simulation of the thermal behavior of a prototype hybrid sensor through the development of an energy balance that involves heat exchange between the different components of the hybrid sensor, and it will allow us to study the influence of internal and external parameters on the temperature variation in the different layers of the prototype PV/T studied.
