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Two-Stream Approximation to the Radiative Transfer Equation:A New Improvement and Comparative Accuracy with Existing Methods

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Advances in Atmospheric Sciences 2024年第2期41卷 278-292页

作者： F.Momo TEMGOUA L.Akana NGUIMDO DNJOMO Environmental Energy Technologies Laboratory(EETL) Faculty of SciencesUniversity of YaoundéPO Box 812 YaoundéCameroon Department of Electrical and Electronic Engineering Faculty of Engineering and TechnologyUniversity of BueaPO Box 63 BueaCameroon

Mathematical modeling of the interaction between solar radiation and the Earth's atmosphere is formalized by the radiative transfer equation(RTE), whose resolution calls for two-stream approximations among other methods. This paper proposes a new two-stream approximation of the RTE with the development of the phase function and the intensity into a third-order series of Legendre polynomials. This new approach, which adds one more term in the expression of the intensity and the phase function, allows in the conditions of a plane parallel atmosphere a new mathematical formulation of γparameters. It is then compared to the Eddington, Hemispheric Constant, Quadrature, Combined Delta Function and Modified Eddington, and second-order approximation methods with reference to the Discrete Ordinate(Disort) method(δ –128 streams), considered as the most precise. This work also determines the conversion function of the proposed New Method using the fundamental definition of two-stream approximation(F-TSA) developed in a previous work. Notably,New Method has generally better precision compared to the second-order approximation and Hemispheric Constant methods. Compared to the Quadrature and Eddington methods, New Method shows very good precision for wide domains of the zenith angle μ 0, but tends to deviate from the Disort method with the zenith angle, especially for high values of optical thickness. In spite of this divergence in reflectance for high values of optical thickness, very strong correlation with the Disort method(R ≈ 1) was obtained for most cases of optical thickness in this study. An analysis of the Legendre polynomial series for simple functions shows that the high precision is due to the fact that the approximated functions ameliorate the accuracy when the order of approximation increases, although it has been proven that there is a limit order depending on the function from which the precision is lost. This observation indicates that increasing the order of approximation of the phase function of the RTE lead

关键词： Radiative Transfer Equation two-stream method Legendre polynomial optical thickness moments of specific intensity conversion function transmittance reflectance

transmittance and phase measurement via self-calibrated balanced heterodyne detection

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Chinese Optics Letters 2018年第6期16卷 44-49页

作者：缪洁张雪洁李展崔子健张琰佳刘德安朱健强 Key Laboratory of High Power Laser and Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China University of Chinese Academy of Sciences Beijing 100049 China

It is rare for a conventional direct detection method to measure the transmittance uniformity of mirrors with rigorous standards, especially to meet the requirement of transmittance/reflectance and phase detection simultaneously. In this study, a new method of self-calibrated balanced heterodyne detection（SCBHD） is proposed. It can be self-calibrated by a two-channel structure to overcome the environmental effects in large optics scanning detection by employing highly accurate heterodyne interference. A typical transmittance measurement experiment was performed at 1053 nm wavelength via SCBHD. A standard deviation（SD） of 0.038% was achieved in the preliminary experiment. The experimental results prove to reduce the SD by approximately two orders of magnitude compared with the conventional direct detection method in the same condition. The proposed method was verified as being promising not only for its wider dynamic measurement range and its higher accuracy but also for its simultaneous transmittance and phase detection ability.

关键词： Heterodyne detection High power lasers Phase measurement Phase modulation Phase shift transmittance

Singular PT-symmetry broken point with infinite transmittance and reflectance--a classical analytical demonstration

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Frontiers of Optoelectronics 2021年第4期14卷 438-444页

作者： Yingxin JIANG Department of Physics Jiangsu UniversityZhenjiang 212013China

To demonstrate the existence of singularparity-time symmetry(PT-symmetry)broken point inoptics system,we designed a one-dimensional PT symmetricstructure including N unit-cell with loss and gainmaterials in half.We performed an analytical deduction toobtain the transmittance and reflectance of the structurebasing on Maxwell’s equations.We found that with theexact structure unit-cell number and the imaginary part ofrefraction index,the transmittance and reflectance are bothclose to infinite.Such strict condition is called the singularpoint in this study.At the singular point position,both thetransmission and reflection are direction-independent.Away from the singular point,the transmittance andreflectance become finite.In light of classical wave optics,the single unit and total structure both become theresonance units.The infinite transmittance and reflectanceresult from the resonance matching of single unit and totalstructure.In light of quantum theory,the singular pointcorresponds to the single eigenvalue of electromagneticscattering matrix.The infinite transmittance and reflectancemean a huge energy transformation from pumpingsource to light waves.Numerical calculation and softwaresimulation both demonstrate the result.

关键词： parity-time symmetric(PT-symmetric)structure singular point transmittance reflectance

Comparing of Light transmittance Aggregometry and Modified Thrombelastograph in Predicting Clinical Outcomes in Chinese Patients Undergoing Coronary Stenting with Clopidogrel

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Chinese Medical Journal 2015年第6期128卷 774-779页

作者： Xiao-Fang Tang Ya-Ling Han Jia-Hui Zhang Jing Wang Yin Zhang Bo Xu Zhan Gao Shu-Bin Qiao Jue Chen Yuan Wu Ji-Lin Chen Run-Lin Gao Yue-Jin Yang Jin-Qing Yuan Department of Cardiology State Key Laboratory of Cardiovascular Disease Fuwai Hospital National Centre for Cardiovascular Diseases Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100037 China Department of Cardiology Institute of Cardiovascular Research of People's Liberation Army Shenyang Northern Hospital Shenyang Liaoning 110840 China Department of Cardiology Centre for Coronary Heart Disease State Key Laboratory of Cardiovascular DiseaseFuwai Hospita/i National Center for Cardiovascular Diseases Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100037 China

Background:Several platelet function tests are currently used to measure responsiveness to antiplatelet therapy.This study was to compare two tests,light transmittance aggregometry (LTA) and modified thrombelastography (mTEG),for predicting clinical outcomes in Chinese patients after percutaneous coronary intervention (PCI).Methods:Prospective,observational,single-center study of 789 Chinese patients undergoing PCI was enrolled.This study was investigated the correlations between the two tests and performed receiver operating characteristic curve (ROC) analysis for major adverse cardiovascular events (MACEs) at 1-year follow-up.Results:MACEs occurred in 32 patients (4.1％).Correlations were well between the two tests in the adenosine diphosphate induced platelet reactivity (Spearman r =0.733,P ＜ 0.001).ROC-curve analysis demonstrated that LTA (area under the curve [AUC]:0.677; 95％ confidence interval [CI]:0.643-0.710; P =0.0009),and mTEG (AUC:0.684; 95％ CI:0.650-0.716; P =0.0001) had moderate ability to discriminate between patients with and without MACE.MACE occurred more frequently in patients with high on-treatment platelet reactivity (HPR) when assessed by LTA (7.4％ vs.2.7％; P ＜ 0.001),and by TEG (6.7％ vs.2.6％; P ＜ 0.001).Kaplan-Meier analysis demonstrated that HPR based on the LTA and mTEG was associated with almost 3-fold increased risk of MACE at 1-year follow-up.Conclusions:The correlation between LTA and mTEG is relatively high in Chinese patients.HPR measured by LTA and mTEG were significantly associated with MACE in Chinese patients undergoing PCI.

关键词： Clopidogrel High On-treatment Platelet Reactivity Light transmittance Aggregometry Thrombelastography

Design and calculation of low infrared transmittance and low emissivity coatings for heat radiative applications

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International Journal of Minerals,Metallurgy and Materials 2012年第2期19卷 179-184页

作者： Cruang-hai Wang Yue Zhang Da-hai Zhang Jin-peng Fan School of Materials Science and Engineering Beihang University Beijing 100191 China National Defence Science ＆ Technology Key Laboratory of Advanced Functional Composites Aerospace Research Institute of Materials and Processing Technology Beijing 100076 China

The infrared transmittance and emissivity of heat-insulating coatings pigmented with various structural particles were studied using Kubelka-Munk theory and Mie theory. The primary design purpose was to obtain the low transmittance and low emissivity coatings to reduce the heat transfer by thermal radiation for high-temperature applications. In the case of silica coating layers constituted with various structural titania particles （solid, hollow, and core-shell spherical）, the dependence of transmittance and emissivity of the coating layer on the particle structure and the layer thickness was investigated and optimized. The results indicate that the coating pigmented with core-shell titania particles exhibits a lower infrared transmittance and a lower emissivity value than that with other structural particles and is suitable to radiative heat-insulating applications.

关键词： scattering pigments coatings transmittance emissivity

Phase transition of shocked water up to 6 GPa:transmittance investigation

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Chinese Physics B 2021年第5期30卷 287-292页

作者：吴浪任月虹廖文强黄曦晨刘福生张明建孙燕云 Key Laboratory of Advanced Technologies of Materials Ministry of Education of ChinaSchool of Physical Science and TechnologySouthwest Jiaotong UniversityChengdu 610031China Sichuan Provincial Key Laboratory(for Universities)of High Pressure Science and Technology Southwest Jiaotong UniversityChengdu 610031China

The phase transition behaviors of the shocked water are investigated by employing an optical transmittance in-situ detection system.Based on the light scattering theory and phase transformation kinetics,the phase transition mechanism of the water under multiple shocks is discussed.The experimental data indicate that the evolution of the transmittance of the shocked water can be broadly divided into three stages:relaxation stage,decline stage,and recovery stage.In the early stage of the phase transition,the new phase particles began to form around the quartz/window interface.It should be mentioned that the water/ice phase boundary seems to move toward the liquid region in one experiment of this work.Due to the new phase core being much smaller than the wavelength of the incident light,the transmittance of the sample within the relaxation stage remains steady.The decline stage can be divided into the rapid descent stage and the slow descent stage in this work,which is considered as the different growth rates of the new phase particle under different shock loadings.The recovery stage is attributed to the emergence of the new phase particles which are bigger than the critical value.However,the influence of the size growth and the population growth of the new phase particles on the transmittance restrict each other,which may be responsible for the phenomenon that the transmittance curve does not return to the initial level.

关键词： phase transition shocked water multiple compresses transmittance scattering

Electron-beam irradiation induced optical transmittance enhancement for Au/ITO and ITO/Au/ITO multilayer thin films

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Journal of Materials Science & Technology 2017年第10期33卷 1107-1112页

作者： Wenzuo Wei Ruijin Hong Jinxia Wang Chunxian Tao Dawei Zhang Engineering Research Center of Optical Instrument and System Ministry of Education and Shanghai Key Lab of Modern Optical System University of Shanghai for Science and Technology Shanghai 200093 China

Electron beam（EB） irradiation experiments on Au/ITO and ITO/Au/ITO multilayer thin films are reported.The structure and the optical-electrical properties of the samples were investigated by X-ray diffraction,atomic force microscopy, four-point probe resistivity measurement system, and UV–vis-NIR double beam spectrometer, respectively. Those results show that the EB irradiation has the effects of improving the crystalline of samples, widening the optical band gap of both thin films, reducing the sheet resistance,and improving the transmittance of samples.

关键词： EB irradiation Multilayer thin films Structure Optical-electrical properties transmittance

A comparison of transmittance properties between ZnO∶Al films for transparent conductors for solar cells deposited by sputtering of AZO and cosputtering of AZO/ZnO

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Rare Metals 2006年第Z1期25卷 105-109页

作者： LEE Chongmu YIM Keunbin CHO Youngjoon Lee J.G. Department of Materials Science and Engineering Inha University 253 Yonghyeon-dong Incheon 402-751 Korea School of Advanced Materials Engineering Kookmin University Seoul 136-702

Aluminum-doped zinc oxide (AZO) thin films were deposited on sapphire (002) and glass substrates by two different sputtering techniques radio frequency magnetron cosputtering of AZO and ZnO targets and sputtering of an AZO target. The dependence of the photoluminescence (PL) and transmittance properties of the AZO films deposited by cosputtering and sputtering on the AZO/ZnO target power ratio, R and the O2/Ar flow ratio, r were investigated, respectively. Only a deep level emission peak appears in the PL spectra of cosputtered AZO films whereas both UV emission and deep level emission peaks are observed in the PL spectra of sputtered AZO films. The absorption edges in the transmittance spectra of the AZO films shift to the lower wavelength region as R and r increase. Effects of crystallinity, surface roughness, PL on the transmittance of the AZO films were also explained using the X-ray diffraction (XRD), atomic force microscopy (AFM), and PL analysis results.

关键词： Al-doped ZnO (AZO) R.F. magnetron sputtering R.F. power transparent conducting oxide (TCO) transmittance

A Parameterized yet Accurate Model of Ozone and Water Vapor transmittance in the Solar-to-near-infrared Spectrum

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Advances in Atmospheric Sciences 2012年第3期29卷 599-610页

作者：刘为一邱金恒 Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of Sciences

A parameterized transmittance model （PTR） for ozone and water vapor monochromatic transmittance calculation in the solar-to-near-infrared spectrum 0.3-4 pm with a spectral resolution of 5 cm-1 was developed based on the transmittance data calculated by Moderate-resolution transmittance model （MOD- TRAN）. Polynomial equations were derived to represent the transmittance as functions of path length and airmass for every wavelength based on the least-squares method. Comparisons between the transmittances calculated using PTR and MODTRAN were made, using the results of MODTRAN as a reference. Rela- tive root-mean-square error （RMSre） was 0.823% for ozone transmittance. RMSre values were 8.84~ and 3.48~ for water vapor transmittance ranges of 1-1 x 10-is and 1-1x 10-3, respectively. In addition, the Stratospheric Aerosol and Gas Experiment II （SAGEII） ozone profiles and University of Wyoming （UWYO） water vapor profiles were applied to validate the applicability of PTR model. RMSre was 0.437~ for ozone transmittance. RMSre values were 8.89~ and 2.43% for water vapor transmittance ranges of 1-1~10-is and 1-1~ 10-6, respectively. Furthermore, the optical depth profiles calculated using the PTR model were compared to the results of MODTRAN. Absolute RMS errors （RMSab） for ozone optical depths were within 0.0055 and 0.0523 for water vapor at all of the tested altitudes. Finally, the comparison between the solar heating rate calculated from the transmittance of PTR and Line-by-Line radiative transfer model （LBLRTM） was performed, showing a maximum deviation of 0.238 K d-1 （6% of the corresponding solar heating rate calculated using LBLRTM）. In the troposphere all of the deviations were within 0.08 K d-1. The computational speed of PTR model is nearly two orders of magnitude faster than that of MODTRAN.

关键词： parameterization transmittance atmospheric absorption