简化紫外辐射模型在基于OMI卫星传感器数据反演西太平洋海面紫外辐射中的应用

将简化紫外辐射传输模型应用于OMI卫星传感器数据,研究西太平洋地区B波段(UVB)的紫外辐射,其中卫星数据取自OMI传感器中L2级数据,地面实测数据取自加拿大全球紫外辐射中心(WOUDC)。将模型反演的UVB辐射数据与位于西北太平洋的两个典型站位实测数据进行了比较,结果显示卫星反演的UVB数据与地面实测数据具有很好的一致性,表明该简化的紫外辐射传输模型在基于OMI卫星传感器数据反演西太平洋地区的UVB辐射时具有良好的适用性。利用卫星反演的UVB数据,研究了西太平洋地区UVB辐射的时间及空间变化规律,这些变化规律与已有的观测结果一致。     

高压放电紫外传感器与检测装置研究

采用光电倍增管(PMT)研制了一种基于紫外光功率法的电力设备放电检测装置.围绕着"日盲"区紫外检测,进行了传感器系统设计,分析了其响应特性.介绍了系统整体结构、系统信号处理模块的软硬件设计,采用数字积分方法实现了紫外光功率测量.使用新装置进行了火花放电和针板放电模拟检测试验,验证了该仪器能够准确检测放电紫外辐射,线性反应放电的强弱,可获得设备放电能量依据.研制的装置工作稳定可靠,灵敏度高,抗干扰能力强,线性度好.     

烟草生产环境监测系统的开发与应用

开发了一个烟草生产环境监测系统,该系统可对烟草生产过程中环境温度、湿度、降雨量、日照全辐射和紫外辐射进行监测.系统测试的数据可通过GSM网络传送到数据巾心,用户可通过访问数据中心服务器查询到相关的生产环境数据;为保证数据的安全性,系统采集到的数据还被保存到SD卡上;可将多个系统组建成为一个监测网络,用于对多个生产基地生产环境进行动态监测;监测系统已经在红塔集团烟叶基地部署了20台,并正常运行半年;系统的部署,为企业原料采购提供重要的决策支持.     

基于涡度数据的东北草地光能利用率模型构建与验证

草地作为地球上分布最广的植被类型,在陆地碳循环中发挥着重要作用。草地生产力是估算产草量的基础,准确模拟生产力对草原资源合理利用及生态保护具有重要意义。以东北草地生产力为研究核心,利用涡度相关通量观测数据、遥感数据和气象数据,构建和检验东北草地光能利用率模型。东北草地光能利用率模型以归一化物候植被指数(NDPI)代表光合有效辐射吸收比例,以地表水分指数(LSWI)+0.5表示水分胁迫因子。基于44个草原站的通量数据对东北草地光能利用率模型进行验证,东北草地光能利用率模型的R²为0.855,高于MODIS GPP产品(R²=0.719),略高于VPM GPP产品(R²=0.848),东北草地光能利用率模型的MAE和RMSE分别为0.374 g Cm^-2和0.735 g Cm^-2,低于MODIS GPP产品(MAE=0.562 g Cm^-2,RMSE=1.026 g Cm^-2)和VPM GPP产品(MAE=0.667 g Cm^-2...     

探测光幕的高速弹丸红外辐射信号获取研究

为了解决光电探测靶在低照度环境下不能工作的问题,提出采用红外探测技术改善其低照度探测性能。利用普朗克定律,分析高速弹丸作用于探测光幕的红外辐射特性;结合探测光幕,分析高速弹丸穿越光幕的红外辐射通亮的变化;利用红外探测器的响应率,建立红外电压信号输出模型,设计红外探测放大电路与数据采集电路,通过实验,飞行弹丸穿越光幕瞬间,探测系统输出的信号明显,在小口径弹作用下,输出幅值可达1V。     

基于ZigBee的太阳能LED照明系统的设计

设计了一种基于ZigBee技术的太阳能LED照明系统,充分考虑了电、热、光的设计.系统结合AVR单片机设计的太阳能控制器具有防止过充过放等保护功能,通过相关传感器采集数据并通过ZigBee无线网络传给监控中心,实时显示采集到的数据,实现无线远程监测与智能控制;通过建立LED热模型,仿真分析了灯具的热均匀分布;通过Matlab计算及Tracepro仿真等过程合理地布置了高低色温LED灯珠间距,并得到了近场照度均匀面.系统测试表明,该系统设计可提供节能高效的、智能稳定的、温馨健康的照明环境.     

基于PSO-ELM算法的红外目标模拟器校准数据拟合方法研究

提高红外目标模拟器校准数据的拟合精度,对于红外目标的辐射照度等辐射特性的测量有着重要意义;针对校准数据具有很强的非线性,传统的拟合算法精度不高的问题,引入一种基于粒子群算法优化的极限学习机算法（PSO-ELM）,以标准黑体辐射温度作为输入因子,以MCT探测器实际测量出的辐射照度作为输出因子,建立PSO-ELM模型,利用粒子群算法（PSO）对连接隐藏神经元和输入层的权值和隐藏神经元阈值进行优化,拟合出输入参数和输出参数之间的非线性关系;这两个参数的优化提高了极限学习机算法（ELM）的性能,该方法的主要优点是具有较强的容错性、较好的对复杂非线性数据处理性能和ELM算法参数设置上的优化机制;通过与GA-ELM模型、ELM模型进行对,验证了与传统数据拟合方法相比,基于PSO-ELM的方法拟合精度有了很大提高,为红外目标模拟器校准数据拟合提供了新的方法。     

近空间高超飞行器气动热红外特性数值仿真

研究飞行器提高自身生存和突防能力,提高红外探测精度,针对近空间高超声速飞行器的气动热红外辐射特性开展了数值仿真研究。利用Jameson中心差分格式,并引入了类TVD变量修正,数值求解三维Navier-Stokes方程获得较为精确的流场参量。以已知流场参量为基础,采用精细的逐线计算模型计算气体的辐射吸收系数,考虑了光谱线的压力增宽和多普勒增宽混合效应;通过有限体积法求解辐射传输方程,空间离散采用与流场相同的计算网格,避免了插值的麻烦,采用了一种较为精确的离散格式。以典型的锥导乘波构型为例,应用所建方法和计算程序数值仿真了其在3~5μm波段的红外辐射空间分布。仿真结果分析表明,模型和方法是合理可行的,可以为红外隐身设计提供一定的参考依据。     

内置面热源密闭方腔内耦合传热数值仿真

为研究温度对固体推进剂点火燃烧性能的影响,需对实验用燃烧室进行温度控制。为进行优化控制,建立了内置面热源的密闭方腔耦合传热模型,利用FLUENT软件,对流动和耦合传热进行了三维数值仿真。计算采用离散坐标(DO)辐射模型,Boussinesq假设。计算结果表明,在自然对流的密闭方腔内,辐射换热比导热和自然对流换热更具主导地位。腔内中心上升的热流与边壁附近下降的冷流形成自然对流环流,环流的速度较高,而上述两部分中间夹层的流体速度较低。数值仿真反映了实验用燃烧室内温度及流场的分布,为实验数据的准确性提供了理论依据。     

曲面环境的一般辐射度方法

基于两微面元间的能量传递理论,本文提出了一种适用于曲面环境的一般辐射度方法.与传统辐射度方法不同的是,本方法假定每一面片上的辐射度是变化的,并引入双线性插值将辐射度系统方程中未知数转化为各面片顶点处的辐射度,从而建立起一整套辐射度系统方程.同时,该一般辐射度方程被拓广至非漫射环境,并导出了一组描述多重镜面和透明面间光能传递的递推公式.理论分析与实验结果证明该方法具有很大的潜力.     

紫外热释电探测器的电学定标分析

在建立有效的紫外热释电探测器三维结构模型基础上,利用Ansys有限元软件的热分析功能,通过以不同的方式对模型施加模拟光辐射的热载荷和模拟电加热的热载荷,观察探测器热释电层的热传递过程并进行温度场分析。结果表明当以相同功率的光和电交替对探测器进行加热时,探测器将最终达到平衡;由于光和电加热的方式有所不同而会产生一定的误差。     

Preferred viewing distance and screen angle of electronic paper displays

This study explored the viewing distance and screen angle for electronic paper (E-Paper) displays under various light sources, ambient illuminations, and character sizes. Data analysis showed that the mean viewing distance and screen angle were 495 mm and 123.7 degrees. The mean viewing distances for Kolin Chlorestic Liquid Crystal display was 500 mm, significantly longer than Sony electronic ink display, 491 mm. Screen angle for Kolin was 127.4 degrees, significantly greater than that of Sony, 120.0 degrees. Various light sources revealed no significant effect on viewing distances; nevertheless, they showed significant effect on screen angles. The screen angle for sunlight lamp (D65) was similar to that of fluorescent lamp (TL84), but greater than that of tungsten lamp (F). Ambient illumination and E-paper type had significant effects on viewing distance and screen angle. The higher the ambient illumination was, the longer the viewing distance and the lesser the screen angle. Character size had significant effect on viewing distances: the larger the character size, the longer the viewing distance. The results of this study indicated that the viewing distance for E-Paper was similar to that of visual display terminal (VDT) at around 500 mm, but greater than normal paper at about 360 mm. The mean screen angle was around 123.7 degrees, which in terms of viewing angle is 29.5 degrees below horizontal eye level. This result is similar to the general suggested viewing angle between 20 degrees and 50 degrees below the horizontal line of sight.     

一种矿用火焰传感器研制

针对现有基于红外检测原理的火焰传感器存在探测距离短、反应时间长等问题,研制了一种基于紫外光检测原理的矿用火焰传感器。通过实验得到了紫外光电管信号调理电路的数学模型,根据该模型得出的电路参数提高了紫外光电管的响应速度;对火焰传感器的供电电源及信号传输电路进行了电磁兼容性设计,提高了火焰传感器的抗干扰能力。测试结果表明,该传感器反应速度快、抗干扰能力强、稳定可靠。     

一种高精度太阳跟踪控制装置研究

提高太阳能跟踪系统的跟踪精度及其稳定性是提高太阳能利用效率及降低成本的重要途径.提出了一种以程控和光控相结合的混合控制高精度太阳能跟踪系统.通过对光电传感器进行改进,使其壁有一定的张角同时增加合适宽度的遮光板用使输出模拟量放大,以提高其稳定性和入射光偏差灵敏度,其中入射光最大偏差为0.105 mm.实验结果表明:该跟踪装置通过太阳光线垂直照射在接收器,从而有效的提高系统的跟踪精度且能够实现全天候自动跟踪.通过误差分析法将实测数据与理论数据进行计算得出跟踪绝对误差在±0.1°以内,比现有的跟踪控制装置更为精确,表明该跟踪控制装置满足稳定可靠、精度高、抗干扰能力强.     

紫外光谱响应度测量系统设计

由于目前的紫外辐射的定标测量存在测量误差大的缺点,采用热释电探测器作为基准探测器给被测探测器(GaN)进行定标,给出光谱响应度测量系统的设计原理,对高稳定度紫外光源系统、热释电电学定标系统、信号检测电路进行了详细的设计,分析计算机控制和软件处理系统部分功能构成,最后进行了单色仪的波长标定来证明系统的准确性。     

车灯线光源优化设计及其反射光亮区的计算机模拟

文章以汽车的一种典型车头灯的线光源优化设计为例,建立了满足具体设计规范的线光源优化设计的非线性规划模型。将线光源离散化为点光源,采用数值方法求出了该模型的最优解。根据所建的模型,用计算机模拟了线光源反射光在测试测试屏上的亮区形状和亮度。     

Mapping solar ultraviolet radiation from satellite data in a tropical environment

This paper presents a technique for mapping erythemally-weighted solar ultraviolet (EUV) radiation from satellite data in a tropical environment. A satellite-based EUV radiation model was formulated for calculating the EUV daily dose from satellite-derived earth-atmospheric albedo, total column ozone and other ground-based ancillary data. The earth-atmospheric albedo was obtained from a geostationary satellite (GMS5) while the total column ozone was retrieved from a polar orbiting satellite (EP/TOMS). The model was validated against the monthly average EUV daily dose from the measurements at four solar radiation monitoring stations located in the tropical environment of Thailand. The monthly average EUV daily dose calculated from the model was in reasonable agreement with that obtained from the measurement, with root mean square difference (RMSD) and mean bias difference (MBD) of 12.3% and 0.7%, respectively. After the validation, the model was used to calculate the monthly average EUV daily dose over Thailand employing an 8-year period of data from GMS5, EP/TOMS and other ancillary surface data. Values of the monthly average of EUV daily dose were presented as monthly and yearly maps. These maps reveal that the tropical monsoons have a strong influence on the EUV in this region.     

实用的MEMS惯性器件外场标定方法

在实际工程应用中,当不具备高精度实验室标定设备时,研究简易可行的MEMS惯性器件外场标定算法非常有必要。在分析MEMS惯性器件误差模型的基础上,提出一种基于椭球模值约束算法的外场标定方法,通过设计合理的实验编排方案和有效的求解算法来实现对误差模型参数的估计。对比实验结果表明:所提出的标定方法简易可行,其误差系数在合理的误差范围内,从而证明了该外场标定方法的有效性。     

Meter-scale large area LED-embedded light fabric for the application of fabric ceilings in rooms

We have developed a meter-scale light emitting diode (LED)-embedded light fabric and its weaving machine for application to a light device for fabric ceilings, which have recently become desired for lightweight safe ceilings in Japan and other countries with frequent earthquakes. The LED fabric structure is 1.2-m-wide woven fabric that has 5-mm-wide LED chip-mounted printed circuit board (PCB) tapes as wefts. LEDs are mounted on the tape of PCBs with a reel-to-reel chip mounting system. Then, the LED-mounted tapes are woven with a developed automatic looming machine that aligns the weft with an accuracy of 0.9 mm, which is suitable for precise arrangement of LEDs and wiring to power supply. A 1.2 × 1.2 m LED-embedded light fabric weighing 320 g/m² was woven. The luminance of the LED fabric is 353 lx at a distance of 1 m, which is the luminance of conventional office lighting. The temperature increase of LEDs without a rigid cooling aluminum plate is only 5.8 °C, and the LED fabric is flexible enough to sustain 1,000 bends down to a radius of 3 mm. This LED fabric and its weaving technology will lead to light devices that have lightweight, large area, and high flexibility for fabric ceilings, walls, and other large areas in homes and offices.     

Simulation of a high-power LED lamp for the evaluation and design of heat dissipation mechanisms

High-power LED lamps have been under intense development in recent years. However, issues related to heat dissipation on the LED chip continue to plague research efforts. Heat generation increases with the power of the LED chip and heat accumulation is exacerbated by the plastic casinge of the lamp. Accumulated heat can seriously shorten the lifespan of an LED device. Consequently, manufacturers are constantly seeking ways to improve heat dissipation via heat transfer mechanisms. Little analysis has been performed on coupling the fluid field and heat dissipation inside LED lamps. Using FLUENT software, this study developed a simulation method for LED lamps in order to investigate thermal and fluid fields inside a lamp. The simulation results of an 8 W LED lamp predicted a chip temperature of 75.1 °C and maximum air velocity of 97.3 mm/s within the lamp with two sets of air circulation. The proposed model facilitates new fin designs and the determination of the optimal inner-shell thickness with the proposed design of a LED lamp having 36 fins and an inner-shell thickness of 1 mm for increased heat dissipation.