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Optimization of regularization parameter of inversion in particle sizing using light extinction method

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China Particuology 2007年第4期5卷 295-299页

作者： Mingxu Su Feng Xu Xiaoshu Cai Kuanfang Ren Jianqi Shen Institute of Particle and Two Phase Flow Measurement Technology University of Shanghai .for Science and Technology Shanghai 200093 China LESP UMR6614/CORIA CNRS-Universite France INSA de Rouen 76801 France

In particle sizing by light extinction method, the regularization parameter plays an important role in applying regularization to find the solution to ill-posed inverse problems. We combine the generalized cross-validation （GCV） and L-curve criteria with the Twomey-NNLS algorithm in parameter optimization. Numerical simulation and experimental validation show that the resistance of the newly developed algorithms to measurement errors can be improved leading to stable inversion results for unimodal particle size distribution.

关键词： Particle size analysis light extinction Inversion algorithm Regularization parameter

Humidity and PM_(2.5) composition determine atmospheric light extinction in the arid region of northwest China

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Journal of Environmental Sciences 2021年第2期33卷 279-286页

作者： Xiaoxiao Zhang Xiang Ding Dilinuer Talifu Xinming Wang Abulikemu Abulizi Mailikezhati Maihemuti Suwubinuer Rekefu Key Laboratory of Coal Clean Conuersion and Chemical Engineering Process Xinjiang Uyghur Autonomous RegionXinjiang UniversityUrumqi 830046China State Key Laboratory of Organic Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640China Guangdong-Hong Kong-Macao Joint Laboratory for Enuironmental Pollution and Control Guangzhou 510640China

Atmospheric visibility can directly reflect the air *** this study,we measured watersoluble ions(WSIs),organic and element carbon(OC and EC)in PM 2.5 from September 2017 to August 2018 in Urumqi,NW *** results show that SO4^2-,NO 3^(-)and NH4^(+)were the major WSIs,together accounting for 7.32%-84.12%of PM 2.5 *** carbon(TC=OC+EC)accounted for 12.12%of PM 2.5 mass on *** OC/EC>2 indicated the formation of secondary organic carbon(SOC).The levels of SO4^2-,NO3^(-)and NH4^(+)in low visibility days were much higher than those in high visibility *** humidity(RH)played a key role in affecting *** extinction coefficient(b ext)that estimated via Koschmieder formula with visibility was the highest in winter(1441.05±739.95 Mm-1),and the lowest in summer(128.58±58.00 Mm^(-)1).The b ext that estimated via IMPROVE formula with PM 2.5 chemical component was mainly contributed by(NH 4)2 SO4 and NH4 *** b ext values calculated by both approaches presented a good correlation with each other(R^2=0.87).Multiple linear regression(MLR)method was further employed to reconstruct the empirical regression model of visibility as a function of PM 2.5 chemical components,NO_(2) and *** results of source apportionment by Positive Matrix Factorization(PMF)model showed that residential coal combustion and vehicle emissions were the major sources of b ext.

关键词： Aerosol chemical composition Visibility IMPROVE light extinction Source apportionment South of Urumqi

Measurements for profiles of aerosol extinction coefficient,backscatter coefficient,and lidar ratio over Wuhan in China with Raman/Mie lidar

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Chinese Optics Letters 2010年第6期8卷 533-536页

作者：龚威张金业毛飞跃李俊 State Key Laboratory for Information Engineering in Surveying Mapping and Remote SensingWuhan University School of Science Hubei University of Technology

The profiles of aerosol extinction,backscatter coefficient,and lidar ratio in the lower troposphere over Wuhan are measured by a multi-channel Raman/Mie *** the lidar ratio retrieved by Raman scattering principle,the profiles of aerosol extinction and backscatter coefficients are also retrieved by Mie scattering signals,without a prior assumption about their relation in the traditional pure Mie signals data *** observations by both Raman and Mie are in good agreement with each *** high coherence shows that the system is reliable,and the Mie and Raman channels are in good adjustment and have the same field of view.

关键词： Atmospheric aerosols Backscattering light extinction Optical radar

Ultraviolet Raman lidar for high-accuracy profiling of aerosol extinction coefficient

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Chinese Optics Letters 2009年第2期7卷 95-97页

作者：高飞宋小全王玉峰周毅华灯鑫 School of Mechanical and Precision Instrument Engineering Xi'an University of Technology Ocean Remote Sensing Institute Ocean University of China School of Mechanical and Precision Instrument Engineering Xi’an University of Technology

An ultraviolet （UV） Raman lidar system at 354.7 nm has been developed for accurately measuring the aerosol extinction profiles. A spectroscopic filter combining a high-spectral-resolution grating with two narrowband mirrors is used to separate the vibrational Raman scattering signal of N2 at a central wavelength of 386.7 nm and the elastic scattering signal at 354.7 nm. The aerosol extinction is derived from the Raman scattering of N2 and the elastic scattering by the use of Raman method and Klett method, respectively. The derived results of aerosol extinction are used to compare the difference of two retrieval methods, and the preliminary experiment shows that the Raman lidar system operated in analog detection mode has the capability of measuring aerosol profiles up to a height of 3 km with a laser energy of 250 mJ and an integration time of 8 min.

关键词： Elastic scattering light extinction Optical radar Raman scattering

A novel scheme of label abstraction and erasion based on Fabry-Perot semiconductor optical amplifier

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Chinese Optics Letters 2007年第1期5卷 14-17页

作者：张薇邱昆凌云庞莹 Key Laboratory of Broadband Optical Fiber Transmission and Communication Networks University of Electronic Science and Technology of China

A novel label abstraction and erasion scheme based on a Fabry-Perot semiconductor optical amplifier （FP-SOA） is proposed for all-optical separation of the bit-serial label from payload and its performance is investigated by simulation. Important features of this scheme are that it does not make use of any high-speed electronics and only one device is needed. be realized with the extinction ratio of 9.72 and 7.05 OCIS codes： 060.4510, 060.1810, 070.4340. Using this scheme, label abstraction and erasion can dB, respectively.

关键词： light extinction

Generation of millimeter-wave sub-carrier optical pulse by using cascaded all-pass cavities

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Chinese Optics Letters 2010年第1期8卷 7-10页

作者：徐钦峰叶青潘政清方祖捷蔡海文瞿荣辉 Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences

A novel scheme is proposed to transform an ultra-short optical pulse to a millimeter-wave frequencymodulated pulse by using the cascaded all-pass cavities （APCs）. The envelope waveform of the generated pulse train is calculated, showing effective improvement by APC cascading. The extinction ratio is analyzed with different input pulses, different cavity reflectivities, and different cascading numbers. It is shown that the cascading does not introduce much effect on the extinction ratio. Two designs by using Gires-Tournois cavity and waveguide ring resonators are proposed to realize the cascaded APC.

关键词： Chemical plants Laser pulses light extinction light pulse generators Millimeter wave devices

All-optical wavelength conversion based on nonlinear polarization rotation (NPR) in SOA and AWG filtering

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Chinese Optics Letters 2006年第4期4卷 205-207页

作者：张君毅伍剑徐坤林金桐 Key Laboratory of Optical Communication and lightwave Technologies Ministry of Education Beijing University of Posts and TelecommunicationsBeijing 100876

An all-optical wavelength converter, based on nonlinear polarization rotation （NPR） in semiconductor optical amplifier （SOA） and array waveguide grating （AWG） filtering, is experimentally demonstrated. The wavelength converter can provide excellent operation including extinction ratio and Q factor. The simultaneous two wavelength conversion outputs are successfully obtained at 20 Gb/s.

关键词： Diffraction gratings light amplifiers light extinction Optical communication Q factor measurement

Compact all-optical switches based on photon-induced suppression of mode interference

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Chinese Optics Letters 2006年第2期4卷 93-95页

作者：李龙志唐奕杨建义王明华江晓清 Department of Information and Electronic Engineering

An optically activated optical switch based on suppression of mode interference （SMI） is presented. The imaging properties of multi-mode interference （MMI） section in the switch with Y-branch can be modified by a controlling light injection. The switch was simulated by finite difference beam propagation method （FD-BPM） and fabricated on GaAlAs/GaAs epitaxial materials. At the wavelength of 1.31 μm, the primary experiment showed an extinction ratio of about 8 dB with controlling light power density of 73.5 W/mm^2.

关键词： Computer simulation Finite difference method Image quality Interference suppression light extinction Photons Semiconducting gallium arsenide Semiconducting gallium compounds

Terahertz Brewster polarizing beam splitter on a polymer substrate

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Chinese Optics Letters 2013年第12期11卷 70-72页

作者：张蒙恩李向军梁士雄刘平安刘建军洪治 Centre for THz Research China Jiliang University Science and Technology on ASIC Laboratory Hebei Semiconductor Research Institute

The performance of a terahertz （THz） Brewster polarizing beam splitter on polymer substrate is studied theoretically and experimentally. Simulations by using finite-element method demonstrate that both trans- nqittance/rei%ctanee and their extinction ratios are better than its 45 °counterpart in a broad frequency range. Especially, the reflection extinction ratio improves significantly. The results are also verified exper- imentally with THz time domain spectroscopy （TDS） and backward wave oscillator （BWO） measurement system.

关键词： light extinction