为进一步提高LED路灯的散热,降低模组的温升,通过对石墨烯材料进行导热结构设计,形成石墨烯高散热碳塑合金散热器,再对其进行光学设计和电路设计,形成50 W LED路灯模组。实测结果表明:50 W的LED路灯模组工作时,温度降低至50.8℃,既保障...为进一步提高LED路灯的散热,降低模组的温升,通过对石墨烯材料进行导热结构设计,形成石墨烯高散热碳塑合金散热器,再对其进行光学设计和电路设计,形成50 W LED路灯模组。实测结果表明:50 W的LED路灯模组工作时,温度降低至50.8℃,既保障LED模组的寿命,也降低光衰,可实现光效高达124.5 lm·W-1。展开更多
Deformation prediction and the analysis of underground goaf are important to the safe and efficient recovery of residual ore when shifting from open-pit mining to underground mining.To address the comprehensive proble...Deformation prediction and the analysis of underground goaf are important to the safe and efficient recovery of residual ore when shifting from open-pit mining to underground mining.To address the comprehensive problem of stability in the double mined-out area of the Tong-Lv-Shan(TLS)mine,which employed the dry stacked gangue technology,this paper applies the function fitting theory and a regression analysis method to screen the sensitive interval of four influencing factors based on single-factor experiments and the numerical simulation software FLAC3D.The influencing factors of the TLS mine consist of the column thickness(d),gob area span(D),boundary pillar thickness(h)and height of tailing gangue(H).The fitting degree between the four factors and the displacement of the gob roof(W)is reasonable because the correlation coefficient(R2)is greater than0.9701.After establishing29groups that satisfy the principles of Box-Behnken design(BBD),the dry gangue tailings process was re-simulated for the selected sensitive interval.Using a combination of an analysis of variance(ANOVA),regression equations and a significance analysis,the prediction results of the response surface methodology(RSM)show that the significant degree for the stability of the mined-out area for the factors satisfies the relationship of h>D>d>H.The importance of the four factors cannot be disregarded in a comparison of the prediction results of the engineering test stope in the TLS mine.By comparing the data of monitoring points and function prediction,the proposed method has shown promising results,and the prediction accuracy of RSM model is acceptable.The relative errors of the two test stopes are1.67%and3.85%,respectively,which yield satisfactory reliability and reference values for the mines.展开更多
This paper proposes a novel microphone array speech denoising scheme based on tensor filtering methods including truncated HOSVD(High-Order Singular Value Decomposition), low rank tensor approximation and multi-mode W...This paper proposes a novel microphone array speech denoising scheme based on tensor filtering methods including truncated HOSVD(High-Order Singular Value Decomposition), low rank tensor approximation and multi-mode Wiener filtering. Microphone array speech signal is represented in three-order tensor space with channel, time, and spectrum modes and then tensor filtering model can be designed to process the multiway array data. As to the first method, noise can be reduced through the truncated HOSVD which is a simple scheme in tensor processing. It is more accurate to find the lower-rank approximation of the three-order tensor with Tucker model. Then MDL(Minimum Description Length) criterion is used to estimate the optimal tensor rank in the second method. Further, multimode Wiener filtering approach upon tensor analysis can be considered as the spanning of one-mode wiener filtering. How to take advantages of tensor model to obtain a set of filters is the heart of the novel scheme. The performances of the proposed three approaches are evaluated with objective indexes and listening quality test. The experimental results indicate that the proposed tenor filtering methods have potential ability of retrieving the target signal from noisy microphone array signal and the multi-mode Wiener filtering method provides the best denoising results among the three ones.展开更多
The leaching behavior of Tunceli malachite mineral was investigated in nitric acid solutions by two steps to evaluate the effect of various experimental parameters.In the first step,the optimal conditions for the leac...The leaching behavior of Tunceli malachite mineral was investigated in nitric acid solutions by two steps to evaluate the effect of various experimental parameters.In the first step,the optimal conditions for the leaching process were determined,while in the second step,a kinetic evaluation for the process was performed.In the optimization experiments,the concentration of nitric acid,temperature,stirring speed,and solid-to-liquid ratio were selected as the independent variables,and the central composite design method(CCD)was applied to the experimental data.At the end of the experiments,the optimal values for the concentration of nitric acid,temperature,solid-to-liquid ratio and stirring speed were determined to be 0.5 mol/L,50℃,0.004 g/m L and 500 r/min,respectively.Under the optimal conditions,the leaching rate was found to be 99%for 120 min of reaction time.In the kinetic evaluation tests,the effects of the concentration of nitric acid,temperature,stirring speed,solid-to-liquid ratio and particle size on the leaching rate of copper from malachite were investigated.In these tests,it was determined that the leaching rate increased with the increase in the temperature,acid concentration and stirring speed,and with the decrease in the particle size and solid-to-liquid ratio.In consequence of the kinetic analysis,it was observed that the leaching kinetics followed the mixed kinetic model,and a mathematical model for the leaching process was introduced.The activation energy for this process was calculated to be 36.23 k J/mol.展开更多
To support modular fixture assembly design in virtual environment,a multi-view based modular fixture virtual assembly model is proposed.Instead of squeezing all assembly related information into a single model,three c...To support modular fixture assembly design in virtual environment,a multi-view based modular fixture virtual assembly model is proposed.Instead of squeezing all assembly related information into a single model,three complementary views of assembly model,element information,function and structure,and assembly relationship are proposed to be used.The first view contains the detailed element information,while the other two explicitly capture the hierarchical function relationships and mating relationships respectively.These views are complementary in the sense that each view only contains a specific aspect of assembly related information while together they include required assembly related information.The proposed assembly model is specialized to accommodate the features of modular fixture virtual assembly design and applied in our developed prototype system.展开更多
Discussing the matter of organizational data management implies, almost automatically, the concept of data warehousing as one of the most important parts of decision support system （DSS）, as it supports the integrat...Discussing the matter of organizational data management implies, almost automatically, the concept of data warehousing as one of the most important parts of decision support system （DSS）, as it supports the integration of information management by aggregating all data formats and provisioning external systems with consistent data content and flows, together with the metadata concept, as one of the easiest ways of integration for software and database systems. Since organizational data management uses the metadata channel for creating a bi-directional flow, when correctly managed, metadata can save both time and resources for organizations. This paperI will focus on providing theoretical aspects of the two concepts, together with a short brief over a proposed model of design for an organizational management tool.展开更多
This study aimed to identify the potential of shrub legumes as protein feed in West Timor. Eight shrub legumes, i.e., Clitoria ternatea Q5455 （CT Q5455）, Clitoria ternatea millgara （CT millgara）, Centrosema pascuo...This study aimed to identify the potential of shrub legumes as protein feed in West Timor. Eight shrub legumes, i.e., Clitoria ternatea Q5455 （CT Q5455）, Clitoria ternatea millgara （CT millgara）, Centrosema pascuorum bundey （CP bundey）, Centrosema pascuorum molle （CP molle）, Macroptilium bracteatum juanita （MB Juanita）, Macroptilium bracteatum cadaarga （MB cadaarga）, Dolichos lablab （DL） and Stylossanthes seabrana （SS） were evaluated for their yield and nutritive value in Randomized Block Design. Each legume was cultivated in four plots of different soil fertility as block （5 ~ 5 m2 per plot）. Phosphorus （P） fertilizer was applied once just before planting at level of 50 kg ha~. Watering was done three times per week using sprinkler. The legumes were harvested at 120 days after planting （dap） in three sub-plots of 1 x 1 m2 size for their yield measurement. Samples of each legume was taken for Dry Matter （DM）, Organic Matter （OM）, Crude Protein （CP）, cellulose, hemi-cellulose and lignin content and in vitro DM, OM and CP digestibility test. Data were statistically analyzed using Genstat release 12.2. The results showed that the legumes showed significantly different （P 〈 0.01） in biomass yield. The highest biomass yield was shown by SS （6,739 kg DM ha-l; 6,120 kg OM ha1 and 1,224 kg CP hal） and the lowest was by DL （1,294 kg DM ha^-1; 1,157 kg OM ha^-1 and 242 kg CP ha^-1）. In general, there was no significant difference （P 〉 0.05） of DM digestibility of the eight legumes, except for DL which showed significantly highest （P 〈 0.01） DM and OM digestibility compared to the other.展开更多
This paper is composed of three elements： 3D modeling, web design and heritage visualization on the basis of the chronological restoration of Fort Frontenac in 1673, 1675, 1680, 1685 and 1688, changing from narrow an...This paper is composed of three elements： 3D modeling, web design and heritage visualization on the basis of the chronological restoration of Fort Frontenac in 1673, 1675, 1680, 1685 and 1688, changing from narrow and plain to broad, grand features. The aim is to use computer graphic design to inform and create an interest in historical visualization by rebuilding Fort Frontenac using 3D modeling and interactive design. The final model can be integrated into an interactive website to learn more about the fort＇s historic importance. It is apparent that using computer graphics can save time and money when it comes to historical visualization. Visitors do not have to travel to the actual archaeological buildings and can simply use the web in their own homes to learn about this information virtually. In order to create a sophisticated restoration of archaeological buildings, meticulously assessing historical records will draw viewers into the visualizations, such as the historical world of Fort Frontenac. As a result, the completed restoration allows the viewers to effectively understand the fort＇s social system, habits and historical events.展开更多
A cogeneration plant can run at off-design due to change of load demand or ambient conditions. The cogeneration considered for this study is gas turbine based engine consists of variable stator vanes （VSVs） compress...A cogeneration plant can run at off-design due to change of load demand or ambient conditions. The cogeneration considered for this study is gas turbine based engine consists of variable stator vanes （VSVs） compressor that are re-staggered for loads greater than 50% to maintain the gas turbine exhaust gas temperature at the set value. In order to evaluate the exergetic performance of the cogeneration, exergy model of each cogeneration component is formulated. A 4.2 MW gas turbine based cogeneration plant is analysed for a wide range of part load operations including the effect of VSVs modulation. For loads less than 50%, the major exergy destruction contributors are the combustor and the loss with the stack gas. At full load, the exergy destructions in the combustor, turbine, heat recovery, compressor and the exergy loss with stack gas are 63.7, 14.1, 11.5, 5.7, and 4.9%, respectively. The corresponding first and second law cogeneration efficiencies are 78.5 and 45%, respectively. For comparison purpose both the first and second law efticiencies of each component are represented together. This analysis would help to identify the equipment where the potential for performance improvement is high, and trends which may aid in the design of future plants.展开更多
In previous studies, N,O-carboxymethyl chitosan has been shown to decrease the incidence and intensity of abdominal adhesions. In the present study, adhesions were induced in 220 rabbits using a double uterine horn mo...In previous studies, N,O-carboxymethyl chitosan has been shown to decrease the incidence and intensity of abdominal adhesions. In the present study, adhesions were induced in 220 rabbits using a double uterine horn model. Rabbits were randomized to receive an operation only or an operation+medical chitosan intraperitoneally. Twenty-two rabbits from each group were euthanized at one of five different times(Day 3, 7, 14, 28, or 42), and adhesion formation was given gross and histopathological scores. Reductions were observed in adhesion extent(P=0.0337) and tenacity(P=0.0271) as well as inflammation(P<0.0001) on Day 3 when medical chitosan was applied. Prior to Day 14, fibrosis was less obvious in the medical chitosan group(P<0.0005). The tenacity scores were significantly lower in the medical chitosan group following Day 14(P<0.05), while the type scores were lower in the medical chitosan group following Day 28(P<0.03). Thus, medical chitosan decreased both the gross and the histopathological scores of the induced adhesions.展开更多
文摘为进一步提高LED路灯的散热,降低模组的温升,通过对石墨烯材料进行导热结构设计,形成石墨烯高散热碳塑合金散热器,再对其进行光学设计和电路设计,形成50 W LED路灯模组。实测结果表明:50 W的LED路灯模组工作时,温度降低至50.8℃,既保障LED模组的寿命,也降低光衰,可实现光效高达124.5 lm·W-1。
基金Project(2017YFC0602902) supported by the National Science and Technology Pillar Program during the 13th Five-Year Plan Period,ChinaProject(2015CX005) supported by the Innovation Driven Plan of Central South University,ChinaProject(2016zzts445) supported by the Fundamental Research Funds for the Central Universities,China
文摘Deformation prediction and the analysis of underground goaf are important to the safe and efficient recovery of residual ore when shifting from open-pit mining to underground mining.To address the comprehensive problem of stability in the double mined-out area of the Tong-Lv-Shan(TLS)mine,which employed the dry stacked gangue technology,this paper applies the function fitting theory and a regression analysis method to screen the sensitive interval of four influencing factors based on single-factor experiments and the numerical simulation software FLAC3D.The influencing factors of the TLS mine consist of the column thickness(d),gob area span(D),boundary pillar thickness(h)and height of tailing gangue(H).The fitting degree between the four factors and the displacement of the gob roof(W)is reasonable because the correlation coefficient(R2)is greater than0.9701.After establishing29groups that satisfy the principles of Box-Behnken design(BBD),the dry gangue tailings process was re-simulated for the selected sensitive interval.Using a combination of an analysis of variance(ANOVA),regression equations and a significance analysis,the prediction results of the response surface methodology(RSM)show that the significant degree for the stability of the mined-out area for the factors satisfies the relationship of h>D>d>H.The importance of the four factors cannot be disregarded in a comparison of the prediction results of the engineering test stope in the TLS mine.By comparing the data of monitoring points and function prediction,the proposed method has shown promising results,and the prediction accuracy of RSM model is acceptable.The relative errors of the two test stopes are1.67%and3.85%,respectively,which yield satisfactory reliability and reference values for the mines.
基金supported by the National Natural Science Foundation of China(No.61571044,No.11590772,No.61473041 and No.61620106002)
文摘This paper proposes a novel microphone array speech denoising scheme based on tensor filtering methods including truncated HOSVD(High-Order Singular Value Decomposition), low rank tensor approximation and multi-mode Wiener filtering. Microphone array speech signal is represented in three-order tensor space with channel, time, and spectrum modes and then tensor filtering model can be designed to process the multiway array data. As to the first method, noise can be reduced through the truncated HOSVD which is a simple scheme in tensor processing. It is more accurate to find the lower-rank approximation of the three-order tensor with Tucker model. Then MDL(Minimum Description Length) criterion is used to estimate the optimal tensor rank in the second method. Further, multimode Wiener filtering approach upon tensor analysis can be considered as the spanning of one-mode wiener filtering. How to take advantages of tensor model to obtain a set of filters is the heart of the novel scheme. The performances of the proposed three approaches are evaluated with objective indexes and listening quality test. The experimental results indicate that the proposed tenor filtering methods have potential ability of retrieving the target signal from noisy microphone array signal and the multi-mode Wiener filtering method provides the best denoising results among the three ones.
基金supported by Munzur University Scientific Investigations Project Unit(PPMUB018-13)。
文摘The leaching behavior of Tunceli malachite mineral was investigated in nitric acid solutions by two steps to evaluate the effect of various experimental parameters.In the first step,the optimal conditions for the leaching process were determined,while in the second step,a kinetic evaluation for the process was performed.In the optimization experiments,the concentration of nitric acid,temperature,stirring speed,and solid-to-liquid ratio were selected as the independent variables,and the central composite design method(CCD)was applied to the experimental data.At the end of the experiments,the optimal values for the concentration of nitric acid,temperature,solid-to-liquid ratio and stirring speed were determined to be 0.5 mol/L,50℃,0.004 g/m L and 500 r/min,respectively.Under the optimal conditions,the leaching rate was found to be 99%for 120 min of reaction time.In the kinetic evaluation tests,the effects of the concentration of nitric acid,temperature,stirring speed,solid-to-liquid ratio and particle size on the leaching rate of copper from malachite were investigated.In these tests,it was determined that the leaching rate increased with the increase in the temperature,acid concentration and stirring speed,and with the decrease in the particle size and solid-to-liquid ratio.In consequence of the kinetic analysis,it was observed that the leaching kinetics followed the mixed kinetic model,and a mathematical model for the leaching process was introduced.The activation energy for this process was calculated to be 36.23 k J/mol.
文摘To support modular fixture assembly design in virtual environment,a multi-view based modular fixture virtual assembly model is proposed.Instead of squeezing all assembly related information into a single model,three complementary views of assembly model,element information,function and structure,and assembly relationship are proposed to be used.The first view contains the detailed element information,while the other two explicitly capture the hierarchical function relationships and mating relationships respectively.These views are complementary in the sense that each view only contains a specific aspect of assembly related information while together they include required assembly related information.The proposed assembly model is specialized to accommodate the features of modular fixture virtual assembly design and applied in our developed prototype system.
文摘Discussing the matter of organizational data management implies, almost automatically, the concept of data warehousing as one of the most important parts of decision support system （DSS）, as it supports the integration of information management by aggregating all data formats and provisioning external systems with consistent data content and flows, together with the metadata concept, as one of the easiest ways of integration for software and database systems. Since organizational data management uses the metadata channel for creating a bi-directional flow, when correctly managed, metadata can save both time and resources for organizations. This paperI will focus on providing theoretical aspects of the two concepts, together with a short brief over a proposed model of design for an organizational management tool.
文摘This study aimed to identify the potential of shrub legumes as protein feed in West Timor. Eight shrub legumes, i.e., Clitoria ternatea Q5455 （CT Q5455）, Clitoria ternatea millgara （CT millgara）, Centrosema pascuorum bundey （CP bundey）, Centrosema pascuorum molle （CP molle）, Macroptilium bracteatum juanita （MB Juanita）, Macroptilium bracteatum cadaarga （MB cadaarga）, Dolichos lablab （DL） and Stylossanthes seabrana （SS） were evaluated for their yield and nutritive value in Randomized Block Design. Each legume was cultivated in four plots of different soil fertility as block （5 ~ 5 m2 per plot）. Phosphorus （P） fertilizer was applied once just before planting at level of 50 kg ha~. Watering was done three times per week using sprinkler. The legumes were harvested at 120 days after planting （dap） in three sub-plots of 1 x 1 m2 size for their yield measurement. Samples of each legume was taken for Dry Matter （DM）, Organic Matter （OM）, Crude Protein （CP）, cellulose, hemi-cellulose and lignin content and in vitro DM, OM and CP digestibility test. Data were statistically analyzed using Genstat release 12.2. The results showed that the legumes showed significantly different （P 〈 0.01） in biomass yield. The highest biomass yield was shown by SS （6,739 kg DM ha-l; 6,120 kg OM ha1 and 1,224 kg CP hal） and the lowest was by DL （1,294 kg DM ha^-1; 1,157 kg OM ha^-1 and 242 kg CP ha^-1）. In general, there was no significant difference （P 〉 0.05） of DM digestibility of the eight legumes, except for DL which showed significantly highest （P 〈 0.01） DM and OM digestibility compared to the other.
文摘This paper is composed of three elements： 3D modeling, web design and heritage visualization on the basis of the chronological restoration of Fort Frontenac in 1673, 1675, 1680, 1685 and 1688, changing from narrow and plain to broad, grand features. The aim is to use computer graphic design to inform and create an interest in historical visualization by rebuilding Fort Frontenac using 3D modeling and interactive design. The final model can be integrated into an interactive website to learn more about the fort＇s historic importance. It is apparent that using computer graphics can save time and money when it comes to historical visualization. Visitors do not have to travel to the actual archaeological buildings and can simply use the web in their own homes to learn about this information virtually. In order to create a sophisticated restoration of archaeological buildings, meticulously assessing historical records will draw viewers into the visualizations, such as the historical world of Fort Frontenac. As a result, the completed restoration allows the viewers to effectively understand the fort＇s social system, habits and historical events.
文摘A cogeneration plant can run at off-design due to change of load demand or ambient conditions. The cogeneration considered for this study is gas turbine based engine consists of variable stator vanes （VSVs） compressor that are re-staggered for loads greater than 50% to maintain the gas turbine exhaust gas temperature at the set value. In order to evaluate the exergetic performance of the cogeneration, exergy model of each cogeneration component is formulated. A 4.2 MW gas turbine based cogeneration plant is analysed for a wide range of part load operations including the effect of VSVs modulation. For loads less than 50%, the major exergy destruction contributors are the combustor and the loss with the stack gas. At full load, the exergy destructions in the combustor, turbine, heat recovery, compressor and the exergy loss with stack gas are 63.7, 14.1, 11.5, 5.7, and 4.9%, respectively. The corresponding first and second law cogeneration efficiencies are 78.5 and 45%, respectively. For comparison purpose both the first and second law efticiencies of each component are represented together. This analysis would help to identify the equipment where the potential for performance improvement is high, and trends which may aid in the design of future plants.
文摘In previous studies, N,O-carboxymethyl chitosan has been shown to decrease the incidence and intensity of abdominal adhesions. In the present study, adhesions were induced in 220 rabbits using a double uterine horn model. Rabbits were randomized to receive an operation only or an operation+medical chitosan intraperitoneally. Twenty-two rabbits from each group were euthanized at one of five different times(Day 3, 7, 14, 28, or 42), and adhesion formation was given gross and histopathological scores. Reductions were observed in adhesion extent(P=0.0337) and tenacity(P=0.0271) as well as inflammation(P<0.0001) on Day 3 when medical chitosan was applied. Prior to Day 14, fibrosis was less obvious in the medical chitosan group(P<0.0005). The tenacity scores were significantly lower in the medical chitosan group following Day 14(P<0.05), while the type scores were lower in the medical chitosan group following Day 28(P<0.03). Thus, medical chitosan decreased both the gross and the histopathological scores of the induced adhesions.
