A light?weight design method of integrated structural topology and size co?optimization for the force?performance?structure of complex structural parts is presented in this paper. Firstly, the supporting function of a...A light?weight design method of integrated structural topology and size co?optimization for the force?performance?structure of complex structural parts is presented in this paper. Firstly, the supporting function of a complex structural part is built to map the force transmission, where the force exerted areas and constraints are considered as connecting structure and the structural configuration, to determine the part performance as well as the force routines. Then the connecting structure design model, aiming to optimize the static and dynamic performances on connection configuration, is developed, and the optimum design of the characteristic parameters is carried out by means of the collaborative optimization method, namely, the integrated structural topology optimization and size optimization. In this design model, the objective is to maximize the connecting stiffness. Based on the relationship between the force and the structural configuration of a part, the optimal force transmission routine that can meet the performance requirements is obtained using the structural topology optimization technology. Accordingly, the light?weight design of conceptual configuration for complex parts under multi?objective and multi?condition can be realized. Finally, based on the proposed collaborative optimization design method, the optimal performance and optimal structure of the complex parts with light weight are realized, and the reasonable structural unit configuration and size charac?teristic parameters are obtained. A bed structure of gantry?type machining center is designed by using the proposed light?weight structure design method in this paper, as an illustrative example. The bed after the design optimization is lighter 8% than original one, and the rail deformation is reduced by 5%. Moreover, the lightweight design of the bed is achieved with enhanced performance to show the effectiveness of the proposed method.展开更多
The woven textile sandwich composite（WTSC） is a promising lightweight composite.In bending,two competing core shearing failure modes reduce the strength;deflection induced by the core shearing deformation reduces th...The woven textile sandwich composite（WTSC） is a promising lightweight composite.In bending,two competing core shearing failure modes reduce the strength;deflection induced by the core shearing deformation reduces the flexural rigidity.To replace a solid composite laminate,the span of WTSC panel must be greater than a critical value,which was deduced on the condition that the load capacity and flexural rigidity of the WTSC panel are equal to those of the composite laminate.Three WTSC panels were tested in bending,so that the failure modes were observed,and the critical spans were determined.Using the alternative design method,the WTSC based wind deflector with reduced weight has been fabricated and mounted on the CRH（China Railway High-speed）.展开更多
Nowadays, lighting design is the modern attractive field of professional activity. Although its theoretical and methodological bases are in the initial stage of formulation. Though there are standards for regulating i...Nowadays, lighting design is the modern attractive field of professional activity. Although its theoretical and methodological bases are in the initial stage of formulation. Though there are standards for regulating illumination quantitatively, the science has never created a bridge to transfer illumination quantity into illumination quality. How to keep a day image of architectural object without imitating natural lighting？ How unrecognizably to change the image, to make it extraordinary and catchy？ This paper offers a solution in the form of external illumination designing principles. This paper proposes two conceptual ways of creating artificial lighting of buildings and constructions that pursue different goals： the principle of ＂tectonic＂ illumination and the principle of ＂decorative＂ illumination. These principles were developed based on the analysis of the state of the art experience of lighting architectural objects and author＇s empirical study. The latter contained measuring luminosity with luminance meter, processing the data, statistical survey （180 respondents） and lighting modeling in the laboratory of Moscow Architectural Institute.展开更多
This paper proposes the financial index of payback period analysis in order to evaluate the economic performance of lighting system. Conventional designs and proposed optimal design using the Energy Conversation Promo...This paper proposes the financial index of payback period analysis in order to evaluate the economic performance of lighting system. Conventional designs and proposed optimal design using the Energy Conversation Promotion Act （No. 2） B.E. 2550 of Ministry of Energy （Section--The Type or Size of Building Standards and Rules and Procedures, Building Design for Energy Conservation, Act B.E. 2552） are compared based on illumination standard for office building in term of energy consumption, return of investment and environmental impact. Firstly, the Type or Size of Building Standards and Rule and Procedures, Building Design for Energy Conservation, Act B.E. 2552 is reviewed and compared with the conventional designs of lighting system for office building. Next, the lifetime energy consumption of fluorescent lamp T5 with electronic ballast, fluorescent lamp T8 with standard ballast and fluorescent lamp T8 with electronic ballast are simulated using DIALux software program in three sizes office buildings. Then, the payback period and CO2 emission of lighting system for selected office building are simulated by various scenarios, which the analytical results show are the optimal lighting system for office building under the present situation. Finally, the optimal design of lighting system for designated office building in Thailand will be discussed with respect to the energy performance with environmental friendly.展开更多
At the scheme design stage,the potential of daylighting is significant due to the saving for electric lighting use. There are few simple tools for architects to optimize the daylighting design. Therefore,it is useful ...At the scheme design stage,the potential of daylighting is significant due to the saving for electric lighting use. There are few simple tools for architects to optimize the daylighting design. Therefore,it is useful to develop a design guideline related to the evaluation of lighting energy saving potential and sunlight design strategies. This paper analyzes the impacts of different artificial lighting control methods and design parameters on daylighting. A direct correlation between lighting energy consumption and parameters such as orientations,window to wall ratio (WWR) and perimeter depth is established. A simplified prediction model is proposed to estimate lighting energy consumption with the given perimeter depth,WWR,and window transparency. Validation of the model is carried out compared with detailed lighting simulation software for an office building. After the variation analysis for these parameters,design advises for the daylighting design at scheme design phase are summarized.展开更多
The compound diffractive telescope is a novel space optical system which combines the structure of compound eyes with diffractive optics and so it has a lighter weight, a wider field of view （FOV）, a lower cost as w...The compound diffractive telescope is a novel space optical system which combines the structure of compound eyes with diffractive optics and so it has a lighter weight, a wider field of view （FOV）, a lower cost as well as looser fabrication tolerance. In this paper, the design of a compound diffractive telescope composed of one primary lens and twenty-one eyepieces is introduced. Then the influence of diffraction orders on the performance of the system is analysed. A modified phase function model of diffractive optics is proposed to analyse the modulation transfer function （MTF） curves for 0° FOV, which provides a more accurate prediction of the performance of the system. In addition, an optimized mechanism is also proposed to suppress stray light. The star image and resolution tests show that the system can achieve diffraction limit imaging within ±2° of FOV and 4-4 mm of eccentricity. Finally, a series of pictures of an object are taken from different channels, and the splicing of pictures from adjacent FOVs is demonstrated. In summary, the designed system has been proved to have great potential applications.展开更多
The design of optical instruments is an active subject due to improvement in lens techniques, fabrication technology, and data handling capacity. Much remains to do to expand its application to phytopathology, which w...The design of optical instruments is an active subject due to improvement in lens techniques, fabrication technology, and data handling capacity. Much remains to do to expand its application to phytopathology, which would be in particular quite useful to improve crop growth monitoring in countries like Mali. An optical multimodal system for plant samples has been developed to improve the characterization of leaf disease symptoms, provide information on their effects, and avoid their spread. Potentially inexpensive components (laser, lens, turntables camera and sample, filter, lens, camera and computer) have been selected, assembled and aligned on an optical table into a multimodal system operating in transmission, reflection, diffusion and fluorescence. The illumination and observation angles can be adjusted to optimize viewing conditions in the four modes. This scientific contribution has been an initiation into the design and implementation of an optical instrument. Initial results are shown and will now be extended in cooperation with agronomic laboratories in African countries for tests on specific plant diseases in relation with prevailing climate conditions.展开更多
A new method for patterned sapphire substrate （PSS） design is developed and proven to be reliable and cost-effective. As progress is made with LEDs＇ luminous efficiency, the pattern units of PSS become more complic...A new method for patterned sapphire substrate （PSS） design is developed and proven to be reliable and cost-effective. As progress is made with LEDs＇ luminous efficiency, the pattern units of PSS become more complicated, and the effect of complicated geometrical features is almost impossible to study systematically by experiments only. By employing our new method, the influence of pattern parameters can be systematically studied, and various novel patterns are designed and optimized within a reasonable time span, with great improvement in LEDs＇ light extraction efficiency （LEE）. Clearly, PSS pattern design with such a method deserves particular attention. We foresee that GaN-based LEDs on these newly designed PSSs will achieve more progress in the coming years.展开更多
The size effects of microstructure of lattice materials on structural analysis and minimum weight design are studied with extented multiscale finite element method（EMsFEM） in the paper. With the same volume of base ...The size effects of microstructure of lattice materials on structural analysis and minimum weight design are studied with extented multiscale finite element method（EMsFEM） in the paper. With the same volume of base material and configuration, the structural displacement and maximum axial stress of micro-rod of lattice structures with different sizes of microstructure are analyzed and compared.It is pointed out that different from the traditional mathematical homogenization method, EMsFEM is suitable for analyzing the structures which is constituted with lattice materials and composed of quantities of finite-sized micro-rods.The minimum weight design of structures composed of lattice material is studied with downscaling calculation of EMsFEM under stress constraints of micro-rods. The optimal design results show that the weight of the structure increases with the decrease of the size of basic sub-unit cells. The paper presents a new approach for analysis and optimization of lattice materials in complex engineering constructions.展开更多
Bubble plumes are important during the process of air-sea exchange,and optical-fiber phase detection is a suitable way to observe bubble plumes entrained by breaking waves.This paper designs a new optical-fiber probe(...Bubble plumes are important during the process of air-sea exchange,and optical-fiber phase detection is a suitable way to observe bubble plumes entrained by breaking waves.This paper designs a new optical-fiber probe(OFP)made of sapphire to overcome the limitations of existing materials(e.g.,high brittleness,poor corrosion resistance,and narrow bandwidth)and thereby enhance the detection performance of the OFP by improving its structure.Based on total internal reflection and light refraction,a simulation model of the probe is established in the Zemax optical design software to optimize the probe tip and matching mode of the two probe tips.The results show that the optimum OFP tip is a conical sapphire one with a cone angle of 35°.Tests are then conducted on a bespoke OFP sensor,the results of which are consistent with those predicted theoretically.The simulation results lay the foundation for the integrated design of OFP sensors and the optimization of their internal optics.The findings could also be applied to OFPs with multiple tips.展开更多
In this paper, we present a comparison of different light-emitting diodes （LEDs） as the light source for long path differential optical absorption spectroscopy （LP-DOAS） atmospheric trace gas measurements. In our ...In this paper, we present a comparison of different light-emitting diodes （LEDs） as the light source for long path differential optical absorption spectroscopy （LP-DOAS） atmospheric trace gas measurements. In our study, we use a fiberoptic design, where high power LEDs used as the light source are coupled into the telescope using a Y shape fiber bundle. Two blue and one ultraviolet （UV） LEDs with different emission wavelength ranges are tested for NO2 and SO2 measurements. The detailed description of the instrumental setup, the NO2 and SO2 retrieval procedure, the error analysis, and the preliminary results from the measurements carried out in Science Island, Hefei, Anhui, China are presented. Our first measurement results show that atmospheric NO2 and SO2 have strong temporal variations in that area and that the measurement accuracy is strongly dependent on the visibility conditions. The measured NO2 and SO2 data are compared to the Ozone Monitoring Instrument （OMI） satellite observations. The results show that the OMI NO2 product underestimates the ground level NO2 by 45%, while the OMI SO2 data are highly influenced by clouds and aerosols, which can lead to large biases in the ground level concentrations. During the experiment, the mixing ratios of the atmospheric NO2 and SO2 vary from 8 ppbv to 36 ppbv and from 3 ppbv to 18 ppbv, respectively.展开更多
This paper discusses the basic principle and design m ethod for light distribution of car lamp, introduces an important development: h igh efficient and flexible car lamp with reflecting light distribution-segmente d ...This paper discusses the basic principle and design m ethod for light distribution of car lamp, introduces an important development: h igh efficient and flexible car lamp with reflecting light distribution-segmente d reflector (multi-patch) car lamp, and puts out a design method for segmented reflector based on error analysis. Unlike classical car lamp with refractive lig ht distribution, the method of reflecting light distribution gives car lamp desi gn more flexibility. In the case of guarantying the lightness of car lamp and sa tisfying the standard demand for the light distribution, the design of the exter ior of the car lamp has more freedom. The high gradient of car lamp is more suit able for the demand of streamline of the car exterior. The shape of segmented re flector obtained by theory calculating of car lamp reflecting light distribution is only an ideal shape, which usually has considerable differences with the fin al shape and will influences light distribution. There exist difference between the calculated reflector and manufactured reflector. Owing to light reflecting c haracter, the small diversification of the reflector will reduce the big diver sification of the light distribution shape on light distribution screen in 25 -meter place, so light distribution quality can’t be ensured. To ensure the re flector by light distribution calculation accordance to reflector by practical m anufacture, the error effect of surface shape must be reasonably considered name ly the error effect of manufacture tache. The paper establishes error-analyzing model for segmented reflector according to the analysis of error of making proc ess for segmented reflector. Based on this error-analyzing model and by use of the analyzing software developed for segmented reflector light distribution, it could reasonably consider reflector errors made by manufacturing, such as reflec tor surface spray-painting and plating aluminum, which could give out shapes of reflector patches for segmented reflector well and truly, and direct the plan o f making process efficiently. The method put by the paper has successfully appli ed to develop segmented reflector lamp for several type cars and obtained good e ffect for the factory.展开更多
In accordance with the enhancement for luminous efficiency improving, LED (Light Emitting Diode) has been gradually developed by combining the characteristics of small volume, impact resistance, good reliability, long...In accordance with the enhancement for luminous efficiency improving, LED (Light Emitting Diode) has been gradually developed by combining the characteristics of small volume, impact resistance, good reliability, long life, low power consumption with multiple purposes for energy saving and environmental protection. Therefore, the array LED has been widely applied in human livings nowadays. This study applies the finite element analysis software ANSYS to analyze the thermal behavior of the array power LED work lamp which is modeled by four same-size LED with MCPCB (Metal Core Print Circuit Board) mounted on a base heat-sink. The Flotran heat flow analysis is applied to obtain the natural convection of air coefficient, while the convection value can be confirmed by the iterative method since it is set as the boundary condition for ANSYS thermal analysis to obtain the temperature distribution, accordingly the chip junction temperature and the base heat-sink temperature were followed through experiments in order to check if the simulation results meet the design requirements and coincide with the power LED product design specification. Prior to the optimal design process for chip junction temperature, the most significant parameters were first chosen by the fractional factorial design. The regressive models were respectively setup by the dual response surface method (RSM) and the mixed response surface method. Furthermore, the genetic algorithm combined with response surface method was applied to acquire the optimal design parameters, and the results were obtained from both methods, which are reviewed for comparison. Afterwards, the mixed response surface method is adopted to investigate the effects of interactions among various factors on chip junction temperature. In conclusion, it is found that the thermal conductivity of MCPCB and the height of base heat-sink are the two major significant factors. In addition, the interactive effects between chip size and thermal conductivity of chip adhesion layer are acknowledged as the most significant interaction influenced on the chip junction temperature.展开更多
基金Supported by National Science and Technology Major Project(Grant No.2015ZX04014021)
文摘A light?weight design method of integrated structural topology and size co?optimization for the force?performance?structure of complex structural parts is presented in this paper. Firstly, the supporting function of a complex structural part is built to map the force transmission, where the force exerted areas and constraints are considered as connecting structure and the structural configuration, to determine the part performance as well as the force routines. Then the connecting structure design model, aiming to optimize the static and dynamic performances on connection configuration, is developed, and the optimum design of the characteristic parameters is carried out by means of the collaborative optimization method, namely, the integrated structural topology optimization and size optimization. In this design model, the objective is to maximize the connecting stiffness. Based on the relationship between the force and the structural configuration of a part, the optimal force transmission routine that can meet the performance requirements is obtained using the structural topology optimization technology. Accordingly, the light?weight design of conceptual configuration for complex parts under multi?objective and multi?condition can be realized. Finally, based on the proposed collaborative optimization design method, the optimal performance and optimal structure of the complex parts with light weight are realized, and the reasonable structural unit configuration and size charac?teristic parameters are obtained. A bed structure of gantry?type machining center is designed by using the proposed light?weight structure design method in this paper, as an illustrative example. The bed after the design optimization is lighter 8% than original one, and the rail deformation is reduced by 5%. Moreover, the lightweight design of the bed is achieved with enhanced performance to show the effectiveness of the proposed method.
基金Project supported by the National Natural Science Foundation of China(Nos.11172089 and 11372095)the State Key Laboratory of Mechanics and Control of Mechanical Structures(Nos.MCMS-0212G01 and MCMS-0215G01)
文摘The woven textile sandwich composite（WTSC） is a promising lightweight composite.In bending,two competing core shearing failure modes reduce the strength;deflection induced by the core shearing deformation reduces the flexural rigidity.To replace a solid composite laminate,the span of WTSC panel must be greater than a critical value,which was deduced on the condition that the load capacity and flexural rigidity of the WTSC panel are equal to those of the composite laminate.Three WTSC panels were tested in bending,so that the failure modes were observed,and the critical spans were determined.Using the alternative design method,the WTSC based wind deflector with reduced weight has been fabricated and mounted on the CRH（China Railway High-speed）.
文摘Nowadays, lighting design is the modern attractive field of professional activity. Although its theoretical and methodological bases are in the initial stage of formulation. Though there are standards for regulating illumination quantitatively, the science has never created a bridge to transfer illumination quantity into illumination quality. How to keep a day image of architectural object without imitating natural lighting？ How unrecognizably to change the image, to make it extraordinary and catchy？ This paper offers a solution in the form of external illumination designing principles. This paper proposes two conceptual ways of creating artificial lighting of buildings and constructions that pursue different goals： the principle of ＂tectonic＂ illumination and the principle of ＂decorative＂ illumination. These principles were developed based on the analysis of the state of the art experience of lighting architectural objects and author＇s empirical study. The latter contained measuring luminosity with luminance meter, processing the data, statistical survey （180 respondents） and lighting modeling in the laboratory of Moscow Architectural Institute.
文摘This paper proposes the financial index of payback period analysis in order to evaluate the economic performance of lighting system. Conventional designs and proposed optimal design using the Energy Conversation Promotion Act （No. 2） B.E. 2550 of Ministry of Energy （Section--The Type or Size of Building Standards and Rules and Procedures, Building Design for Energy Conservation, Act B.E. 2552） are compared based on illumination standard for office building in term of energy consumption, return of investment and environmental impact. Firstly, the Type or Size of Building Standards and Rule and Procedures, Building Design for Energy Conservation, Act B.E. 2552 is reviewed and compared with the conventional designs of lighting system for office building. Next, the lifetime energy consumption of fluorescent lamp T5 with electronic ballast, fluorescent lamp T8 with standard ballast and fluorescent lamp T8 with electronic ballast are simulated using DIALux software program in three sizes office buildings. Then, the payback period and CO2 emission of lighting system for selected office building are simulated by various scenarios, which the analytical results show are the optimal lighting system for office building under the present situation. Finally, the optimal design of lighting system for designated office building in Thailand will be discussed with respect to the energy performance with environmental friendly.
基金Project(2006BAJ02A02) supported by the National Key Technologies R & D Program of China
文摘At the scheme design stage,the potential of daylighting is significant due to the saving for electric lighting use. There are few simple tools for architects to optimize the daylighting design. Therefore,it is useful to develop a design guideline related to the evaluation of lighting energy saving potential and sunlight design strategies. This paper analyzes the impacts of different artificial lighting control methods and design parameters on daylighting. A direct correlation between lighting energy consumption and parameters such as orientations,window to wall ratio (WWR) and perimeter depth is established. A simplified prediction model is proposed to estimate lighting energy consumption with the given perimeter depth,WWR,and window transparency. Validation of the model is carried out compared with detailed lighting simulation software for an office building. After the variation analysis for these parameters,design advises for the daylighting design at scheme design phase are summarized.
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2006AA12Z127)the National Natural Science Foundation of China (Grant No. 10704072)the Innovation Program of Chinese Academy of Sciences
文摘The compound diffractive telescope is a novel space optical system which combines the structure of compound eyes with diffractive optics and so it has a lighter weight, a wider field of view （FOV）, a lower cost as well as looser fabrication tolerance. In this paper, the design of a compound diffractive telescope composed of one primary lens and twenty-one eyepieces is introduced. Then the influence of diffraction orders on the performance of the system is analysed. A modified phase function model of diffractive optics is proposed to analyse the modulation transfer function （MTF） curves for 0° FOV, which provides a more accurate prediction of the performance of the system. In addition, an optimized mechanism is also proposed to suppress stray light. The star image and resolution tests show that the system can achieve diffraction limit imaging within ±2° of FOV and 4-4 mm of eccentricity. Finally, a series of pictures of an object are taken from different channels, and the splicing of pictures from adjacent FOVs is demonstrated. In summary, the designed system has been proved to have great potential applications.
文摘The design of optical instruments is an active subject due to improvement in lens techniques, fabrication technology, and data handling capacity. Much remains to do to expand its application to phytopathology, which would be in particular quite useful to improve crop growth monitoring in countries like Mali. An optical multimodal system for plant samples has been developed to improve the characterization of leaf disease symptoms, provide information on their effects, and avoid their spread. Potentially inexpensive components (laser, lens, turntables camera and sample, filter, lens, camera and computer) have been selected, assembled and aligned on an optical table into a multimodal system operating in transmission, reflection, diffusion and fluorescence. The illumination and observation angles can be adjusted to optimize viewing conditions in the four modes. This scientific contribution has been an initiation into the design and implementation of an optical instrument. Initial results are shown and will now be extended in cooperation with agronomic laboratories in African countries for tests on specific plant diseases in relation with prevailing climate conditions.
基金Project supported by the National Natural Science Fundation for Excellent Young Scholars of China(Grant No.51422203)the National Natural Science Foundation of China(Grant No.51372001)+1 种基金the Outstanding Youth Foundation of Guangdong Scientific Committee(Grant No.S2013050013882)the Strategic Special Funds for LEDs of Guangdong Province,China(Grant Nos.2011A081301010,2011A081301012,2012A080302002,and 2012A080302004)
文摘A new method for patterned sapphire substrate （PSS） design is developed and proven to be reliable and cost-effective. As progress is made with LEDs＇ luminous efficiency, the pattern units of PSS become more complicated, and the effect of complicated geometrical features is almost impossible to study systematically by experiments only. By employing our new method, the influence of pattern parameters can be systematically studied, and various novel patterns are designed and optimized within a reasonable time span, with great improvement in LEDs＇ light extraction efficiency （LEE）. Clearly, PSS pattern design with such a method deserves particular attention. We foresee that GaN-based LEDs on these newly designed PSSs will achieve more progress in the coming years.
基金supported by the National Natural Science Foundation of China(11372060,10902018,91216201,and 11326005)the National Basic Research Program of China(2011CB610304)the Major National Science and Technology Project(2011ZX02403-002)
文摘The size effects of microstructure of lattice materials on structural analysis and minimum weight design are studied with extented multiscale finite element method（EMsFEM） in the paper. With the same volume of base material and configuration, the structural displacement and maximum axial stress of micro-rod of lattice structures with different sizes of microstructure are analyzed and compared.It is pointed out that different from the traditional mathematical homogenization method, EMsFEM is suitable for analyzing the structures which is constituted with lattice materials and composed of quantities of finite-sized micro-rods.The minimum weight design of structures composed of lattice material is studied with downscaling calculation of EMsFEM under stress constraints of micro-rods. The optimal design results show that the weight of the structure increases with the decrease of the size of basic sub-unit cells. The paper presents a new approach for analysis and optimization of lattice materials in complex engineering constructions.
文摘Bubble plumes are important during the process of air-sea exchange,and optical-fiber phase detection is a suitable way to observe bubble plumes entrained by breaking waves.This paper designs a new optical-fiber probe(OFP)made of sapphire to overcome the limitations of existing materials(e.g.,high brittleness,poor corrosion resistance,and narrow bandwidth)and thereby enhance the detection performance of the OFP by improving its structure.Based on total internal reflection and light refraction,a simulation model of the probe is established in the Zemax optical design software to optimize the probe tip and matching mode of the two probe tips.The results show that the optimum OFP tip is a conical sapphire one with a cone angle of 35°.Tests are then conducted on a bespoke OFP sensor,the results of which are consistent with those predicted theoretically.The simulation results lay the foundation for the integrated design of OFP sensors and the optimization of their internal optics.The findings could also be applied to OFPs with multiple tips.
基金Project supported by the National High-Technology Research and Development Program of China (Grant No. 2009AA063006)the National Natural Science Foundation of China (Grant No. 60808034)
文摘In this paper, we present a comparison of different light-emitting diodes （LEDs） as the light source for long path differential optical absorption spectroscopy （LP-DOAS） atmospheric trace gas measurements. In our study, we use a fiberoptic design, where high power LEDs used as the light source are coupled into the telescope using a Y shape fiber bundle. Two blue and one ultraviolet （UV） LEDs with different emission wavelength ranges are tested for NO2 and SO2 measurements. The detailed description of the instrumental setup, the NO2 and SO2 retrieval procedure, the error analysis, and the preliminary results from the measurements carried out in Science Island, Hefei, Anhui, China are presented. Our first measurement results show that atmospheric NO2 and SO2 have strong temporal variations in that area and that the measurement accuracy is strongly dependent on the visibility conditions. The measured NO2 and SO2 data are compared to the Ozone Monitoring Instrument （OMI） satellite observations. The results show that the OMI NO2 product underestimates the ground level NO2 by 45%, while the OMI SO2 data are highly influenced by clouds and aerosols, which can lead to large biases in the ground level concentrations. During the experiment, the mixing ratios of the atmospheric NO2 and SO2 vary from 8 ppbv to 36 ppbv and from 3 ppbv to 18 ppbv, respectively.
文摘This paper discusses the basic principle and design m ethod for light distribution of car lamp, introduces an important development: h igh efficient and flexible car lamp with reflecting light distribution-segmente d reflector (multi-patch) car lamp, and puts out a design method for segmented reflector based on error analysis. Unlike classical car lamp with refractive lig ht distribution, the method of reflecting light distribution gives car lamp desi gn more flexibility. In the case of guarantying the lightness of car lamp and sa tisfying the standard demand for the light distribution, the design of the exter ior of the car lamp has more freedom. The high gradient of car lamp is more suit able for the demand of streamline of the car exterior. The shape of segmented re flector obtained by theory calculating of car lamp reflecting light distribution is only an ideal shape, which usually has considerable differences with the fin al shape and will influences light distribution. There exist difference between the calculated reflector and manufactured reflector. Owing to light reflecting c haracter, the small diversification of the reflector will reduce the big diver sification of the light distribution shape on light distribution screen in 25 -meter place, so light distribution quality can’t be ensured. To ensure the re flector by light distribution calculation accordance to reflector by practical m anufacture, the error effect of surface shape must be reasonably considered name ly the error effect of manufacture tache. The paper establishes error-analyzing model for segmented reflector according to the analysis of error of making proc ess for segmented reflector. Based on this error-analyzing model and by use of the analyzing software developed for segmented reflector light distribution, it could reasonably consider reflector errors made by manufacturing, such as reflec tor surface spray-painting and plating aluminum, which could give out shapes of reflector patches for segmented reflector well and truly, and direct the plan o f making process efficiently. The method put by the paper has successfully appli ed to develop segmented reflector lamp for several type cars and obtained good e ffect for the factory.
文摘In accordance with the enhancement for luminous efficiency improving, LED (Light Emitting Diode) has been gradually developed by combining the characteristics of small volume, impact resistance, good reliability, long life, low power consumption with multiple purposes for energy saving and environmental protection. Therefore, the array LED has been widely applied in human livings nowadays. This study applies the finite element analysis software ANSYS to analyze the thermal behavior of the array power LED work lamp which is modeled by four same-size LED with MCPCB (Metal Core Print Circuit Board) mounted on a base heat-sink. The Flotran heat flow analysis is applied to obtain the natural convection of air coefficient, while the convection value can be confirmed by the iterative method since it is set as the boundary condition for ANSYS thermal analysis to obtain the temperature distribution, accordingly the chip junction temperature and the base heat-sink temperature were followed through experiments in order to check if the simulation results meet the design requirements and coincide with the power LED product design specification. Prior to the optimal design process for chip junction temperature, the most significant parameters were first chosen by the fractional factorial design. The regressive models were respectively setup by the dual response surface method (RSM) and the mixed response surface method. Furthermore, the genetic algorithm combined with response surface method was applied to acquire the optimal design parameters, and the results were obtained from both methods, which are reviewed for comparison. Afterwards, the mixed response surface method is adopted to investigate the effects of interactions among various factors on chip junction temperature. In conclusion, it is found that the thermal conductivity of MCPCB and the height of base heat-sink are the two major significant factors. In addition, the interactive effects between chip size and thermal conductivity of chip adhesion layer are acknowledged as the most significant interaction influenced on the chip junction temperature.
