首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 117 毫秒
1.
本文根据作业车间凋度问题的数学模型和特点,首先改进了经典的TS和SA算法,在此基础上提出了一套基于关键路理论的混合优化算法,实现了关键路理论和混合优化策略的有机结合;应用此算法对该调度问题的一些实例进行了计算验证,实践证明本算法能显著提高优化效果和效率。该套方法对实现自动化、智能化的车间调度系统提供了较好的算法支持。  相似文献   

2.
白光LED是一种符合环保和节能的绿色照明光源,而红色荧光粉的性能对白光LED的显色指数及色温的影响极其显著.氮化物材料的结构和组成的多样性,以及独特的局部配位环境使其具有丰富的发光颜色、可协调发光性、较高的量子效率和较小的热猝灭性等发光性能.本文主要从晶体结构、发光特性、量子效率、化学稳定性和物理稳定性等方面总结了不同类型的氮化物红色荧光粉的最新研究成果和发展现状.最后,对氮化物红色荧光粉的研究进行了展望.  相似文献   

3.
白光LED具有低压、低功耗、高可靠性和长寿命等一系列优点,是一种符合节能环保的绿色照明光源.现阶段的白光LED显色指数低、色温较高,限制了白光LED在室内照明等领域的发展,而红色荧光粉能对白光LED的显色指数的提高及色温的改善影响极其显著.主要介绍白光LED用红色荧光粉几大主要体系的发光性质及最新发展现状.  相似文献   

4.
杨玮  李沁  王晓雅  岳婷 《包装工程》2019,40(7):134-141
目的研究子母穿梭车式立体仓库中复合作业路径优化问题,有利于提高系统运行效率,降低成本。方法对于子母穿梭车式立体仓库在一次存取货作业中复合作业方式的实际调度路径,考虑到其运动机构的加(减)速度,以完成复合作业总时间最短为目标建立数学模型。针对该系统复合作业的运行特征,提出一种结合遗传和蚁群算法各自优点的混合粒子群算法进行优化求解。结果实例验证可知,与粒子群算法和蚁群算法相比,文中提出的混合粒子群算法具有性能稳定、优化效率更高等优点。结论文中所提复合作业路径优化方法能够有效地缩短子母穿梭车式立体仓库的复合作业时间,提高了进出库调度效率。  相似文献   

5.
杨玮  王晓雅  岳婷  张据燕  王婷 《包装工程》2018,39(7):173-179
目的为提高双载具式多层穿梭车立体仓库的运作效率,对其货位优化进行研究。方法针对双载具式多层穿梭车立体仓库货位优化作业系统的特点,考虑其运动过程中的加(减)速度特性,建立以入库时间最短为目标的货位分配优化模型。通过设计结合交叉变异算子的混合植物繁殖算法对该模型进行优化求解,从而确定最佳货位分配方案,缩短货位分配时间。结果实例分析表明,混合植物繁殖算法与遗传算法和物繁殖算法相比,收敛速度更快、优化效率更高。结论混合植物繁殖算法能够有效地缩短双载具式多层穿梭车立体仓库的货位分配时间,提高了仓库运作效率。  相似文献   

6.
服装样片裁剪空行程路径是影响裁床裁剪效率的重要因素,裁剪路径优化有助于提高裁剪效率。针对裁剪空行程优化问题,先构建了裁剪空行程路径的数学模型,结合遗传算法和蚁群算法的优势,提出了遗传蚁群混合算法优化裁剪空行程。算法先利用遗传算法的快速搜索能力建立蚁群算法的初始信息素分布,然后采用蚁群算法求精确解,最后建立仿真实验验证混合算法的可行性,与基本遗传算法相比,混合算法具有较优的全局优化性能。  相似文献   

7.
基于并行混沌和复合形法的桁架结构形状优化   总被引:1,自引:0,他引:1  
针对多工况下受应力、位移和局部稳定性约束的桁架形状优化问题,提出了基于并行混沌优化算法和复合形法的混合优化算法。该算法综合利用了并行混沌的全局搜索能力,复合形法的快速局部搜索能力和混沌细搜索。首先,利用并行混沌优化算法快速搜索到全局最优解附近,然后应用改进复合形法以并行混沌的优化解为初始复形进行搜索,提高了最优解的搜索速度,最后应用混沌细搜索策略提高最优解的精度。两个典型数值算例验证了该混合优化方法对桁架形状优化问题的有效性和稳定性。  相似文献   

8.
用于固态体积式真三维立体显示的LED投影照明系统研究   总被引:4,自引:1,他引:3  
合肥工业大学开发的固态体积式真三维立体显示器包括单片DMD、UHP投影光源、RGBRGB六段4倍速色轮、方棒、20层液晶光阀组成的显示体、投影镜头、折叠光路、控制电路等,存在刷新率低、色域小的问题.本文设计了基于LED的投影照明系统,包括RGB三原色LED发光模块、混合聚光镜、X棱镜等,替换样机中的UHP光源和色轮.红...  相似文献   

9.
裴云  邢益良  陈敏 《硅谷》2015,(2):48-49
在很多应用领域都要用到串匹配算法,本文介绍了防抄袭检测技术、串匹配技术,在RKR-GST算法研究的基础上,利用该算法实现了教学平台的防抄袭系统模块,该模块使用后,很大程度上提高了检测抄袭的效率和准确性,最后对模块进行了系统的测试。  相似文献   

10.
制备了铕离子掺杂氧氮玻璃陶瓷,研究了该玻璃陶瓷的发光性能。X射线衍射结果表明玻璃基质中析出了CaAl2Si2O8,Ca2Al2SiO7和Y20Si12O48N4等晶体。随着Si3N4成分的增加或热处理的进行,玻璃陶瓷中一些Eu3+离子被还原成Eu2+离子。我们认为Eu3+被还原为Eu2+主要源自于6Eu3++2N3-→6Eu2++N2↑氧化还原反应,或者源自于析出的CaAl2Si2O8和Ca2Al2SiO7晶相中Eu3+对Ca2+的取代。玻璃陶瓷除了产生类似于玻璃中三价Eu3+离子f-f跃迁的橘红色发光外,还出现了源自于d-f跃迁的Eu2+离子超宽带蓝绿色发光。因此,玻璃陶瓷中Eu3+离子的橘红色发光和Eu2+离子的蓝绿色发光混合产生了白色发光,具有更高的发光强度和白光显色指数,在LED照明领域展示出很好的潜在应用前景。  相似文献   

11.
Pawlak A  Zaremba K 《Applied optics》2008,47(3):467-473
The lighting parameters of LEDs are constantly improving. They should not however be applied directly in general lighting luminaires. Luminous intensity distribution solid of high power LEDs is inappropriate for the uniform lighting of a target surface and produces too high of a luminance for this luminaire for large elevation angles. We analyzed the luminous intensity curves allowing us to achieve the best possible lighting uniformity and limited distribution of the luminous flux. Specially manufactured reflectors with limited height were applied in the designed luminaire model. The application of 30 white and additionally six red diodes in the same luminaire provided the resulting optical radiation with the color temperature of 3702 K and a color rendering index of 81.  相似文献   

12.
随着LED技术的持续发展,其检测方法和评价标准成为了世界LED产业所面临的共同挑战。该文介绍了LED模块的光强分布、光通量、光强、相关色温、显色指数、色品坐标、色品容差、平均颜色不均匀性和最大颜色不均匀性等光色性能参数的测试方法,并结合自己在检测LED模块产品检测工作中的积累,总结了LED模块相具体条件下应选用的测试方法。  相似文献   

13.
Swift PD  Smith GB 《Applied optics》2003,42(25):5112-5117
We present modeled results of the luminous and color outputs of a three-layer stack of fluorescent planar concentrators (FPCs). FPCs have the potential to provide sufficient luminous output to illuminate moderate-sized rooms for reasonably-sized collecting areas. It is of course necessary not only that the lumens be sufficient, but also that the light be sufficiently white as to be comfortable. Modeling shows that by use of a stack of three FPCs, one each of violet, green, and red, it is possible to achieve good color rendering and sufficient lighting levels for room illumination.  相似文献   

14.
Abstract

By adding red-emitting α-SrO·3B2O3:Sm2+ phosphor and SiO2 co-doping particles to yellow-emitting YAG:Ce phosphor compound, a novel method for improving lighting performance of white LEDs with remote phosphor structure, which have an average correlated color temperature (CCT) of 5600–8500 K, is proposed and demonstrated. By varying α-SrO·3B2O3:Sm2+ concentration from 2 to 30% and maintaining 5% SiO2, the obtained results indicated that color rendering index (CRI), color quality scale (CQS), and luminous flux can be increased significantly. Moreover, the Mie-scattering theory is employed to verify the scattering properties, which have an effect on the enhancement of color quality and luminous flux. The results prove a prospective practical solution for manufacturing remote phosphor white LED (RP-WLED) having higher color quality and luminous flux.  相似文献   

15.
张帆  刘慧  王勇 《上海计量测试》2012,(1):32-33,36
介绍两种光源光通量测量方法:加V(λ)修正的光度计法和分光法,比较各自的特点,并分析影响光通量测量结果的因素。加V(λ)修正的光度计法测量光通量简捷、快速,但无法同时测量光色参数。随着新型光电测试技术的日益成熟,光谱辐射计性能越发完善,除了测量光源光通量,还可计算光源的色品坐标、色温、显色指数、色容差等色度参数。在CIE127中分光法被推荐为测量光源光色参数的方法。  相似文献   

16.
固态照明具有功率大、亮度高、体积小、节能环保等优点, 已成为21世纪最有前景的照明技术。作为固态照明关键材料, 荧光材料的性能直接决定固态照明器件的显色指数、流明效率和可靠性等技术参数。相较于荧光单晶、荧光玻璃、荧光薄膜及量子阱, 荧光陶瓷因具有优异的热学和光学性质及微观结构易调控等特点, 被认为是综合性能最优的大功率固态照明用荧光材料。未来, 荧光陶瓷将在汽车大灯、户外照明、激光电视、激光影院等领域得到更广泛的应用和发展, 具有广阔的市场前景。本文探讨了大功率固态照明用荧光陶瓷的设计原则, 重点介绍了目前研究相对较多的氧化物荧光陶瓷(主要指钇铝石榴石结构)和氮(氧)化物荧光陶瓷的研究进展, 最后对大功率固态照明用荧光陶瓷的未来发展方向进行了展望。  相似文献   

17.
传统“荧光粉+有机硅脂”荧光转换体的热导率低, 且物理化学稳定性差, 不能应用于高功率白光LED领域。全无机荧光块体材料可以规避有机封装, 具有更高的热导率, 但这类材料面临着成本高且极难实现立体结构的问题。本工作基于非晶态纳米二氧化硅, 得到一种包含(Gd,Y)AG:Ce荧光粉、可在紫外光下固化的浆料, 并通过光固化成型、空气排脂、无压烧结, 制备了一种(Gd,Y)AG:Ce荧光粉-石英玻璃复合材料。该荧光玻璃陶瓷在蓝光激发下发射峰值位于575 nm的宽带橙黄光, 且内量子效率大于90%。研究结果表明, 在致密化烧结过程中, (Gd,Y)AG:Ce荧光粉与石英玻璃之间的界面反应非常微弱, 因此荧光粉能够完好地嵌入到石英玻璃中。该全无机荧光转换体可以用于封装相关色温小于4500 K、显色指数大于75和流明效率为74 lm·W-1的高功率暖白光LED。所构建的激光照明器件的饱和激光功率密度可达2.84 W·mm-2, 此时光通量为180 lm。此外, 所提出的制备方法与3D打印兼容, 可以批量化制造出具有复杂立体结构的荧光转换体。该技术有望推动高功率白光LED朝着个性化和模块化发展。  相似文献   

18.
Plasma and thin films for lighting application Thin films play an important role in the lighting industry. Well known products are reflectors with simple aluminium coating or with dichroic coatings for cold light mirrors. Especially for energy saving applications special halogen bulbs are coated with a transparent hot mirror that increases the overall efficiency up to 50 % while keeping the positive properties of halogen lighting like color, color rendering index, start up performance and others unchanged. Special thin film applications realize color filters, IR filters, UV filters or color conversion filters. All these processes are vacuum processes that work with plasma assistance. The most prominent technologies for cost effective production are the PICVD processes (former development of SCHOTT AG in cooperation with Auer Lighting) and the Microdyn® technology from DSI, Santa Rosa.  相似文献   

19.
Abstract

A superior alternative to the conventional hydrargyrum medium-arc iodide (HMI) luminaires, high power light emitting diode (HP-LED) luminaires are increasingly being utilized in numerous modern lighting designs and applications. Specifically, this research is concerned with the comparative optical and electrical performance and engineering economic analysis of Fresnel-type HMI and HP-LED luminaires for studio lighting applications in the experiments conducted in a real studio environment. The findings revealed that, optically, the Correlated color temperature, luminous flux, luminous intensity and illuminance of the experimental HP-LED and HMI luminaires were comparable. The Color rendering index of the HP-LED was higher and its beam/spread output was more controllable. In the electrical aspect, the results showed that the HP-LED luminaire required significantly less power while producing lower %THDv and %THDi vis-à-vis the HMI counterpart. The payback period for the replacement of HP-LED luminaires was around 7 years and 7 months, which was shorter than the project life of 15 years. The commercial prospect of HP-LED luminaires is thus brighter as an excellent substitute for the conventional HMI luminaires in myriad applications, particularly in studio lighting for photography, cinematography, and broadcasting.  相似文献   

20.
Commercial white light‐emitting diodes (LEDs) have the undesirable characteristics of blue‐rich emission and low color rendering index (CRI), while the constituent quantum dots (QDs) suffer from aggregation‐induced fluorescence quenching and poor stability. Herein, a strategy is developed to assemble tricolor QDs into a polysiloxane matrix using a polymer‐mediated hybrid approach whereby the hybrid composite exhibits a significant enhancement of aggregation‐dispersed emission, outstanding photostability, high thermal stability, and outstanding fluorescence recovery. Using the as‐prepared hybrid fluorescent materials, the fabricated LEDs exhibit solar spectrum‐simulated emission with adjustable Commission Internationale de L'Eclairage coordinates, correlated color temperature, and a recorded CRI of 97. Furthermore, they present no ultraviolet emission and weak blue emission, thus indicating an ideal healthy and high‐CRI white LED lighting source.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号