A new algorithm is presented that generates developable Bézier surfaces through a Bézier curve called a directrix. The algorithm is based on differential geometry theory on necessary and sufficient condition...A new algorithm is presented that generates developable Bézier surfaces through a Bézier curve called a directrix. The algorithm is based on differential geometry theory on necessary and sufficient conditions for a surface which is developable, and on degree evaluation formula for parameter curves and linear independence for Bernstein basis. No nonlinear characteristic equations have to be solved. Moreover the vertex for a cone and the edge of regression for a tangent surface can be obtained easily. Aumann’s algorithm for developable surfaces is a special case of this paper.展开更多
Dipolar and quadrupolar resonance wavelengths of SiO_(2)/Au nanoshell surface plasmons are designed at 560 nm to enhance the light trapping in thin film solar cells.In order to quantitatively describe the light trappi...Dipolar and quadrupolar resonance wavelengths of SiO_(2)/Au nanoshell surface plasmons are designed at 560 nm to enhance the light trapping in thin film solar cells.In order to quantitatively describe the light trapping effect,the forward−scattering efficiency(FSE)and the light trapping efficiency(LTE)are proposed by considering the light scattering direction of SiO_(2)/Au nanoshells.Based on the Mie theory,the FSE and the LTE are calculated for SiO_(2)/Au nanoshells of different dimensions,and the contributions of the dipolar and quadrupolar modes to the light trapping effect are analyzed in detail.When the surface coverage of nanoshells is 5%,the LTEs are 21.7%and 46.9%for SiO_(2)/Au nanoshells with sizes of(31 nm,69 nm)and(53 nm,141 nm),respectively.The results indicate that the SiO_(2)/Au nanoshell whose quadrupolar mode peak is designed to the strongest solar energy flux density of the solar spectrum facilitates the further enhancement of light harvesting in thin film solar cells.展开更多
采用溶胶-凝胶法制备了双金属氧化物Ti/IrSbO_(x)电极,表征了电极的析氯电位、析氯稳定性、法拉第效率、活性氯产量、工作寿命等电化学性能,利用电催化氧化反应系统研究了该电极对不同水质工业氨氮废水的处理效果。结果表明,Ti/IrSbO_(x...采用溶胶-凝胶法制备了双金属氧化物Ti/IrSbO_(x)电极,表征了电极的析氯电位、析氯稳定性、法拉第效率、活性氯产量、工作寿命等电化学性能,利用电催化氧化反应系统研究了该电极对不同水质工业氨氮废水的处理效果。结果表明,Ti/IrSbO_(x)电极在10 mA/cm^(2)的电流密度下的析氯电位为2.04 V vs RHE,20h电解反应后的电极电势仅增大0.48%,在0.05 M NaCl溶液中的法拉第效率为64.33%,在20 mA/cm^(2)的电流密度下活性氯产量达到8.51 mg/h,在20 mA/cm^(2)电流密度下的工作寿命为21.12年。通过电催化氧化反应系统处理低氯子浓度(2000 mg/L)工业氨氮废水时较市售电极有更高的电流效率,为该电极的工业化应用提供了理论依据和实践经验。展开更多
基金Project supported by the National Basic Research Program (973) of China (No. 2004CB719400), the National Natural Science Founda-tion of China (Nos. 60373033 and 60333010) and the National Natural Science Foundation for Innovative Research Groups (No. 60021201), China
文摘A new algorithm is presented that generates developable Bézier surfaces through a Bézier curve called a directrix. The algorithm is based on differential geometry theory on necessary and sufficient conditions for a surface which is developable, and on degree evaluation formula for parameter curves and linear independence for Bernstein basis. No nonlinear characteristic equations have to be solved. Moreover the vertex for a cone and the edge of regression for a tangent surface can be obtained easily. Aumann’s algorithm for developable surfaces is a special case of this paper.
基金by the Natural Science Foundation of Beijing under Grant No 2102042the National Natural Science Foundation of China under Grant No 61006050+1 种基金the Fundamental Research Funds for the Central Universities under Grant No 10QG24the National Basic Research Program of China under Grant No 2010CB933800.
文摘Dipolar and quadrupolar resonance wavelengths of SiO_(2)/Au nanoshell surface plasmons are designed at 560 nm to enhance the light trapping in thin film solar cells.In order to quantitatively describe the light trapping effect,the forward−scattering efficiency(FSE)and the light trapping efficiency(LTE)are proposed by considering the light scattering direction of SiO_(2)/Au nanoshells.Based on the Mie theory,the FSE and the LTE are calculated for SiO_(2)/Au nanoshells of different dimensions,and the contributions of the dipolar and quadrupolar modes to the light trapping effect are analyzed in detail.When the surface coverage of nanoshells is 5%,the LTEs are 21.7%and 46.9%for SiO_(2)/Au nanoshells with sizes of(31 nm,69 nm)and(53 nm,141 nm),respectively.The results indicate that the SiO_(2)/Au nanoshell whose quadrupolar mode peak is designed to the strongest solar energy flux density of the solar spectrum facilitates the further enhancement of light harvesting in thin film solar cells.
文摘采用溶胶-凝胶法制备了双金属氧化物Ti/IrSbO_(x)电极,表征了电极的析氯电位、析氯稳定性、法拉第效率、活性氯产量、工作寿命等电化学性能,利用电催化氧化反应系统研究了该电极对不同水质工业氨氮废水的处理效果。结果表明,Ti/IrSbO_(x)电极在10 mA/cm^(2)的电流密度下的析氯电位为2.04 V vs RHE,20h电解反应后的电极电势仅增大0.48%,在0.05 M NaCl溶液中的法拉第效率为64.33%,在20 mA/cm^(2)的电流密度下活性氯产量达到8.51 mg/h,在20 mA/cm^(2)电流密度下的工作寿命为21.12年。通过电催化氧化反应系统处理低氯子浓度(2000 mg/L)工业氨氮废水时较市售电极有更高的电流效率,为该电极的工业化应用提供了理论依据和实践经验。
