突发性洪水研究的现状及发展趋势

突发性洪水研究的现状及发展趋势穆宏强（蒲圻长江职工大学蒲圻４３７３０２）１９９４年９月２６～２９日，由联合国教科文组织、国际水文计划中国国家委员会、南京水文水资源研究所、美国亚里桑那大学水文水资源系等１４个单位主办，西安理工大学承办的干旱半于旱地区突...     

基于蚁群算法的三峡库区洪水优化调度

为解决三峡水利枢纽汛期的洪水调度问题,根据三峡库区洪水优化调度问题的具体需求,以蚁群箅法为基础建立了求解该问题的模型和求解方法,并对三峡水库典型洪水的洪水优化调度问题进行了仿真计算.结果表明,蚁群算法能够有效求解水库洪水优化调度问题,计算效果也较好.     

Ultra-broadband of up to 200 nm near-infrared phosphors based on one-site occupation strategy for multipurpose applications in light-emitting diodes

Portable near-infrared (NIR) lighting source stimulates great efforts to exploit NIR phosphor-converted LEDs (pc-LEDs) that push the rapid development of broadband NIR-emitting phosphors. Although Cr³⁺-activated NIR phosphors designed by multisites occupation strategy show significant potential in emission bandwidth, poor spectral stability caused by different thermal quenching behaviors is a brake on practical application due to different local structure around Cr centers. One-site-based NIR phosphors seem to be an effective method to solve aforementioned problem. Herein, we report a type of new ultra-broadband one-site-based NIR-emitting phosphors NaSc_1-xP₂O₇:xCr³⁺ (NSP:xCr³⁺) with emission at 910 nm and full width at half maximum (FWHM) of up to ～200 nm. Their FWHM value exceeds all one-site-based Cr³⁺-activated phosphors and some multiple-sites ones. Structural analysis and low-temperature spectra demonstrate that such impressive broadband NIR emission originates from Cr³⁺ occupying at single octahedral Sc site. At 425 K, integrated emission intensity of NSP:0.04Cr³⁺ phosphor maintains 53.8% of room temperature. A NIR pc-LED prototype is fabricated by using NSP:0.04Cr³⁺ phosphor with a blue LED chip, and its multipurpose applications in non-destructive detection, night vision and analysis of foodstuff are demonstrated. These findings indicate that broadband NSP:0.04Cr³⁺ NIR phosphor enabled by one-site occupation strategy has potential prospect for multipurpose NIR pc-LEDs applications.