Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extens...Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extensive attention due to their advantages of small size,high multiplexing efficiency,convenient mass production,and low cost.An RGB beam combiner based on directional couplers is designed,with a core-cladding relative refractive index difference of 0.75%.The RGB beam combiner is optimized from the perspective of parameter optimization.Using the beam propagation method(BPM),the relationship between the performance of the RGB beam combiner and individual parameters is studied,achieving preliminary optimization of the device’s performance.The key parameters of the RGB beam combiner are optimized using the entropy weight-technique for order preference by similarity to an ideal solution TOPSIS method,establishing the optimal parameter scheme and further improving the device’s performance indicators.The results show that after optimization,the multiplexing efficiencies for red,green,and blue lights,as well as the average multiplexing efficiency,reached 99.17%,99.76%,96.63%and 98.52%,respectively.The size of the RGB beam combiner is 4.768 mm×0.062 mm.展开更多
适应城市化进程加速与气候变化,提高抵御洪涝灾害的能力是可持续发展的必由之路。从韧性视角出发,构建基于“自然-经济-社会-基础设施”的洪涝韧性评估框架,运用组合赋权-逼近理想解排序模型(Technique for Order Preference by Similar...适应城市化进程加速与气候变化,提高抵御洪涝灾害的能力是可持续发展的必由之路。从韧性视角出发,构建基于“自然-经济-社会-基础设施”的洪涝韧性评估框架,运用组合赋权-逼近理想解排序模型(Technique for Order Preference by Similarity to the Ideal Solution,TOPSIS)评估2007—2022年南京都市圈城市洪涝韧性水平,并利用障碍度模型诊断抑制洪涝韧性提升的主要因素。结果表明:(1)都市圈城市洪涝韧性呈上升趋势,从较低水平转变为中等水平;(2)洪涝韧性空间分布呈现以南京为核心、向四周辐射递减的“中心-外围”特征;(3)研究时段末南京都市圈洪涝韧性的关键限制因素有河流调蓄能力、人口脆弱度、政府财政情况,植被覆盖率为部分城市潜在障碍因素。研究可为南京都市圈完善洪涝灾害防治体系、提升洪涝韧性提供参考。展开更多
为克服单一赋权法的局限性,结合山区干线公路交通特征及交通安全评价指标的选取原则,从社会因素、驾驶因素、环境因素、管理因素和道路因素五个维度出发,选取18个综合评价指标,运用序关系分析法(Order Relation Analysis Method,G1)-指...为克服单一赋权法的局限性,结合山区干线公路交通特征及交通安全评价指标的选取原则,从社会因素、驾驶因素、环境因素、管理因素和道路因素五个维度出发,选取18个综合评价指标,运用序关系分析法(Order Relation Analysis Method,G1)-指标相关性权重确定法(Criteria Importance Through Intercriteria Correlation,CRITIC)确定各评价指标的权重,并结合折中妥协多属性决策法(VlseKriterijumska Optimizacija I Kompromisno Resenje,VIKOR)对山区干线公路交通安全进行综合评价,提出了基于G1-CRITIC-VIKOR模型的山区干线公路交通安全综合评价及比选方法。以中国西部6条山区干线公路为例进行实证研究,结果表明,G1-CRITIC-VIKOR模型的评价效果与传统的秩和比(Rank-Sum Ratio,RSR)综合评价法及加权逼近理想解排序法(Technique for Order Preference by Similarity to Ideal Solution,TOPSIS)的评价结果基本一致,且评价效果明显优于后者,具有更好的辨识性,验证了该模型的可行性和科学性。展开更多
基金Project(52175445)supported by the National Natural Science Foundation of ChinaProject(2022JJ30743)supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(2023GK2024)supported by the Key Research and Development Program of Hunan Province,ChinaProject(2023ZZTS0391)supported by the Fundamental Research Funds for the Central Universities of China。
文摘Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extensive attention due to their advantages of small size,high multiplexing efficiency,convenient mass production,and low cost.An RGB beam combiner based on directional couplers is designed,with a core-cladding relative refractive index difference of 0.75%.The RGB beam combiner is optimized from the perspective of parameter optimization.Using the beam propagation method(BPM),the relationship between the performance of the RGB beam combiner and individual parameters is studied,achieving preliminary optimization of the device’s performance.The key parameters of the RGB beam combiner are optimized using the entropy weight-technique for order preference by similarity to an ideal solution TOPSIS method,establishing the optimal parameter scheme and further improving the device’s performance indicators.The results show that after optimization,the multiplexing efficiencies for red,green,and blue lights,as well as the average multiplexing efficiency,reached 99.17%,99.76%,96.63%and 98.52%,respectively.The size of the RGB beam combiner is 4.768 mm×0.062 mm.
文摘适应城市化进程加速与气候变化,提高抵御洪涝灾害的能力是可持续发展的必由之路。从韧性视角出发,构建基于“自然-经济-社会-基础设施”的洪涝韧性评估框架,运用组合赋权-逼近理想解排序模型(Technique for Order Preference by Similarity to the Ideal Solution,TOPSIS)评估2007—2022年南京都市圈城市洪涝韧性水平,并利用障碍度模型诊断抑制洪涝韧性提升的主要因素。结果表明:(1)都市圈城市洪涝韧性呈上升趋势,从较低水平转变为中等水平;(2)洪涝韧性空间分布呈现以南京为核心、向四周辐射递减的“中心-外围”特征;(3)研究时段末南京都市圈洪涝韧性的关键限制因素有河流调蓄能力、人口脆弱度、政府财政情况,植被覆盖率为部分城市潜在障碍因素。研究可为南京都市圈完善洪涝灾害防治体系、提升洪涝韧性提供参考。
文摘为克服单一赋权法的局限性,结合山区干线公路交通特征及交通安全评价指标的选取原则,从社会因素、驾驶因素、环境因素、管理因素和道路因素五个维度出发,选取18个综合评价指标,运用序关系分析法(Order Relation Analysis Method,G1)-指标相关性权重确定法(Criteria Importance Through Intercriteria Correlation,CRITIC)确定各评价指标的权重,并结合折中妥协多属性决策法(VlseKriterijumska Optimizacija I Kompromisno Resenje,VIKOR)对山区干线公路交通安全进行综合评价,提出了基于G1-CRITIC-VIKOR模型的山区干线公路交通安全综合评价及比选方法。以中国西部6条山区干线公路为例进行实证研究,结果表明,G1-CRITIC-VIKOR模型的评价效果与传统的秩和比(Rank-Sum Ratio,RSR)综合评价法及加权逼近理想解排序法(Technique for Order Preference by Similarity to Ideal Solution,TOPSIS)的评价结果基本一致,且评价效果明显优于后者,具有更好的辨识性,验证了该模型的可行性和科学性。
