一种道路照明光源的光视光效模型研究

文章依据视觉功效法建立基于中间视觉道路照明的行车视觉行为反应时间测试系统,获取受测试数据集;根据人眼对光谱敏感度适应效应理论,对实验测试数据进行分析处理,构建了基于行车视觉行为反应时间的光视光效模型,获得了中间视觉下光视光效率曲线;采用建立的模型给出了基于反应时间的光源节能性评价计算分析方法,并对道路照明传统白色和黄白色光源与设计的白绿色光源进行了光视光效性能分析与节能评价。结果表明,在中间视觉下设计的白绿色光源光视性能更好,且光视效能更高。

基于反应时间的中间视觉道路照明功率密度分析及显色性能研究

给出了一种在人眼中间视觉条件下道路照明光源安全节能性能分析的研究方法。通过构建基于中间视觉行车行为反应时间模拟测试系统,建立了人眼中间视觉条件下的光视光效模型,获得了中间视觉下的光视光效曲线。并通过该模型,给出了基于照明功率密度LPD的光源节能性评价方法。从色度学理论出发,选用Luv均匀颜色空间,基于显色指数的光源显色性评价分析计算方法,探讨了不同主波长光源的相对光谱功率分布变化对光源颜色的影响,建立了光源主波长与显色指数的函数关系表达式,可计算获得人眼敏感度与光源颜色各个波长点的关系。对上述方法进行了反应时间模拟测试实验和道路照明图像清晰度计算实验验证,数据分析与计算结果表明,在中间视觉条件下,以540~550 nm为主波长的白绿色照明光源的功率密度和显色性最佳。

照明系统能效分析及评价技术

提出照明系统的照度指标、照度均匀度指标、显色指数指标、光效模型、镇流器效率模型、照明功率密度模型。基于上述模型、指标及照明管理节能技术,构建照明系统运行能效评价指标体系和对应的能效诊断方法,指标体系涵盖灯具能效、照明舒适度、运行管理水平三方面的技术参数。

Small-Signal Equivalent Circuit Modeling of a Photodetector Chip

A small-signal equivalent circuit model and the ted. The equivalent lumped circuit, which takes the main extraction techniques for photodetector chips are presen- factors that limit a photodetector＇s RF performance into consideration,is first determined based on the device＇s physical structure. The photodetector＇s S parameters are then on-wafer measured, and the measured raw data are processed with further calibration. A genetic algorithm is used to fit the measured data, thereby allowing us to calculate each parameter value of the model. Experimental resuits show that the modeled parameters are well matched to the measurements in a frequency range from 130MHz to 20GHz, and the proposed method is proved feasible. This model can give an exact description of the photodetector chip＇s high frequency performance,which enables an effective circuit-level prediction for photodetector and optoelectronic integrated circuits.

Evaluation of Spectral Scale Effects in Estimation of Vegetation Leaf Area Index Using Spectral Indices Methods

Spectral index methodology has been widely used in Leaf Area Index(LAI) retrieval at different spatial scales. There are differences in the spectral response of different remote sensors and thus spectral scale effect generated during the use of spectral indices to retrieve LAI. In this study, PROSPECT, leaf optical properties model and Scattering by Arbitrarily Inclined Layers(SAIL) model, were used to simulate canopy spectral reflectance with a bandwidth of 5 nm and a Gaussian spectral response function was employed to simulate the spectral data at six bandwidths ranging from 10 to 35 nm. Additionally, for bandwidths from 5 to 35 nm, the correlation between the spectral index and LAI, and the sensitivities of the spectral index to changes in LAI and bandwidth were analyzed. Finally, the reflectance data at six bandwidths ranging from 40 to 65 nm were used to verify the spectral scale effect generated during the use of the spectral index to retrieve LAI. Results indicate that Vegetation Index of the Universal Pattern Decomposition(VIUPD) had the highest accuracy during LAI retrieval. Followed by Normalized Difference Vegetation Index(NDVI), Modified Simple Ratio Indices(MSRI) and Triangle Vegetation Index(TVI), although the coefficient of determination R^2 was higher than 0.96, the retrieved LAI values were less than the actual value and thus lacked validity. Other spectral indices were significantly affected by the spectral scale effect with poor retrieval results. In this study, VIUPD, which exhibited a relatively good correlation and sensitivity to LAI, was less affected by the spectral scale effect and had a relatively good retrieval capability. This conclusion supports a purported feature independent of the sensor of this model and also confirms the great potential of VIUPD for retrieval of physicochemical parameters of vegetation using multi-source remote sensing data.

Studies on Forecast Model of Photosynthetic Active Radiation in Sunlight Greenhouse in Winter in Panjin

In order to explore the law of photosynthetic active radiation in winter sunlight greenhouse in Panjin and serve the local facility agriculture better,based on the observed data of sunlight greenhouse microclimate and of the nearby weather station during winter in 2012,the methods of correlation analysis and stepwise regression analysis were adopted to study characteristics of photosynthetic active radiation in sunlight greenhouse and the ratio of photosynthetic active radiation to global radiation under different weather types during winter,and to set up forecast models of photosynthetic active radiation in sunlight greenhouse under different weather types during winter.The results showed that：（1） the daily variation of photosynthetic active radiation in sunlight greenhouse on sunny and cloudy days were both obvious,and photosynthetic active radiation in sunlight greenhouse was 1-38 W/m^2 when it＇s cloudy.（2） ηPARon typical cloudy day was the highest,on cloudy day was secondary and on sunny day was the minimum during winter;（3） the methods of stepwise regression analysis were respectively adopted to set up models of the highest daily maximum photosynthetic active radiation,the total daily photosynthetic active radiation,daily maximum global radiation,and the total daily global radiation in sunlight greenhouse associated with climate outside,the models passed the 0.01 level of significance,and fitting test had been carried out：4 factors were fitted well on sunny and cloudy day,but fitted poor on overcast day.

Properties of Linear Entropy in k-Photon Jaynes-Cummings Model with Stark Shift and Kerr-Like Medium

The time evolution of the linear entropy of an taking into consideration Stark shift and Kerr-like medium. atom in k-photon daynes-Cummings model is investigated The effect of both the Stark shift and Kerr-like medium on the linear entropy is analyzed using a numerical technique for the field initially in coherent state and in even coherent state. The results show that the presence of the Kerr-like medium and Stark shift has an important effect on the properties of the entropy and entanglement. It is also shown that the setting of the initial state plays a significant role in the evolution of the linear entropy and entanglement.

Scattering loss in optical waveguide with trapezoidal cross section

To get the scattering loss of the trapezoidal core waveguide,a new analysis model is presented based on the perturbation equivalent method and modified effective-index method.Firstly,the trapezoidal core waveguide is successfully equivalent to the rectangular one with both restricting the same optical field energy by adopting the perturbation method,Then,the equivalent rectangular core waveguide is decomposed into two slab waveguides by employing the modified effective-index method,The trapezoidal core waveguide scattering theory model is established based on the slab waveguide scattering theory.With the sidewalls surface roughness in the range from 0 to 100 nm in the single model trapezodial core waveguide,optical simulation shows excellent agreement with the results from the scattering loss model presented.The relationship between the dimension and side-wall roughness with the scattering loss can be determined in the trapezoidal core waveguide by the scattering loss model.

Mechanism of Bragg Diffraction-Assisted Light Extraction in GaN-based Light-Emitting Diodes Based on a Self-Consistent Model

By introducing the distribution of the light energy density in GaN-based light-emitting diode (LED),theLED model based on the incoherent regime and the light extraction efficiency are investigated.The energy density asa function of the angle of incidence is calculated to demonstrate the mechanism of the light extraction.The deviationbetween the tendencies of the transmissivity of the output layer and the extraction efficiency is also demonstrated.

Regional Oceanic Impact on Circulation and Direct Radiative Effect of Aerosol over East Asia

The Regional Integrated Environmental Model System （RIEMS 2.0） coupled with a chemistry-aerosol model and the Princeton Ocean Model （POM） is employed to simulate regional oceanic impact on atmospheric circulation and the direct radiative effect （DRE） of aerosol over East Asia. The aerosols considered in this study include both major anthropogenic aerosols （e.g., sulfate, black carbon, and organic carbon） and natural aerosols （e.g., soil dust and sea salt）. The RIEMS 2.0 is driven by NCEP/NCAR reanalysis II, and the simulated period is from 1 January to 31 December 2006. The results show the following： （1） The simulated annual mean sea-level pressure by RIEMS 2.0 with POM is lower than without POM over the mainland and higher without POM over the ocean. （2） In summer, the subtropical high simulated by RIEMS 2.0 with POM is stronger and extends further westward, and the continental low is stronger than without POM in summer. （3） The aerosol optical depth （AOD） simulated by RIEMS 2.0 with POM is larger in the middle and lower reaches of the Yangtze River than without POM. （4） The direct radiative effect with POM is stronger than that without POM in the middle and lower reaches of the Yangtze River and parts of southern China. Therefore, the authors should take account of the impact of the regional ocean model on studying the direct climate effect ＆aerosols in long term simulation.

A Model for Extreme Ultraviolet Radiation Conversion Efficiency From Laser Produced Mass-Limited Tin-Based Droplet Target Plasmas

Simple arguments are used to construct a model to explain the extreme ultraviolet radiation conversion efficiency(EUV-CE) of a tin-based droplet target laser produced plasmas by calculating the laser absorption efficiency,radiation efficiency,and spectral efficiency.The dependence of drive laser pulse duration and laser intensity on EUV-CE is investigated.The results show that at some appropriate laser intensity,where the sum energy of the thermal conduction,out-off band radiation and plasma plume kinetic losses is at a minimum,the EUV-CE should reach a maximum.The EUV-CE predicted by the present simple model is also compared with the available experimental and simulation data and a fair agreement between them is found.

Investigation of shunt solar cells’ currents based on equivalent circuit model

In view of the universality of the parallel connection of solar cells and their mismatch problem, in the present paper, we select two shunt solar cells (connected in parallel) as our research object, and use the equivalent one-diode circuit of the solar cell and the analysis of the two-body model. At first, the equations of current and voltage are deduced from the related electrical laws and the circuit diagram of the two solar cells connected in parallel. Then, according to the experimentally measured data of typical single-crystalline silicon solar cells (125 mm×125 mm), we select the appropriate simulation parameters. Following this, by using the photo-generated current, the shunt resistance, and the serial resistance of one of the shunt solar cells and the load resistance as independent variables, in turn, the changing characteristics of each branch current in the two shunt solar cells are numerically discussed and analyzed for these four cases for the first time. At the same time, we provide a simple physical explanation for the modeling results. Our analyses show that these parameters have different impacts on the internal currents of solar cells connected in parallel. These results provide a reference to solve the problem of connecting solar cells and to develop higher efficiency solar cells and systems. Meanwhile, the results will contribute to a better comprehension of the reasons for efficiency loss of solar cells and systems, and deepen the understanding of the electrical of solar cells behavior for high performance photovoltaic applications.