Journals >Laser & Optoelectronics Progress
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2011
Volume: 48 Issue 2
19 Article(s)
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Atmospheric Optics and Oceanic Optics
Tilt Power Spectra Measurements and Frequency Analysis of Disturbed Wavefront in Horizontal Turbulence
Liu Chao, Hu Lifa, Mu Quanquan, Cao Zhaoliang, and Xuan Li
In design of an adaptive optics system, a critical consideration is the bandwidth requirements for turbulence-induced tilt compensation, Tyler frequency. A method to evaluate the Tyler frequency is proposed according to the measured total tilt power spectrum. First, the power spectrum of the horizontal turbulence is meIn design of an adaptive optics system, a critical consideration is the bandwidth requirements for turbulence-induced tilt compensation, Tyler frequency. A method to evaluate the Tyler frequency is proposed according to the measured total tilt power spectrum. First, the power spectrum of the horizontal turbulence is measured through a Shark-Hartmann wavefront sensor. Then, the Tyler frequency is determined by which the tilt cut-off residual error of a diffraction angle is applied. The result illustrates that the tilt power spectrum is proportional to f-2 (f is temporal frequency) at high frequencies. At last, the circadian variation of Tyler frequency is acquired. It illustrates the important fact that, at night and early morning, the Tyler frequency of horizontal turbulence changes slowly, generally less than 4Hz in the turbulence condition, but it is volatile during the day, the largest up to about 20 Hz in Changchun. Therefore, the temporal bandwidth of the tip-tilt, in which the adaptive optics systems are used for the horizontal turbulence correction under such turbulence condition, must exceed 20 Hz..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 20101 (2011)
Detectors
Design of Readout Circuit for Pyroelectric Detector Based on Relaxor Ferroelectric Single Crystals
Wang Jiang, and Jing Weiping
Relaxor-based ferroelectric single crystals, such as (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT, or PMNT) single crystals, exhibit large pyroelectric response, low thermal diffusivity and high temperature stability. To fabricate high performance infrared detectors with relaxor-based single crystals, the related readout cirRelaxor-based ferroelectric single crystals, such as (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT, or PMNT) single crystals, exhibit large pyroelectric response, low thermal diffusivity and high temperature stability. To fabricate high performance infrared detectors with relaxor-based single crystals, the related readout circuit is investigated to increase signal-to-noise ratio, and 8×1 CMOS readout circuit is fabricated to gain very weak current..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 20401 (2011)
Fiber Optics and Optical Communications
Microstructed Fiber for Low-Threshold Mid-IR Supercontinuum Generation
Xie Dong, Wen Jianguo, Zhao Chujun, and Xia Lanye
A new microstructured fiber for low-threshold mid-infrared (mid-IR) supercontinuum generation is proposed and designed. The transmission parameters and mode field intensity are calculated by multipole method. The results show the fiber has high nonlinear coefficient, widely flattened chromatic dispersion, low confinemeA new microstructured fiber for low-threshold mid-infrared (mid-IR) supercontinuum generation is proposed and designed. The transmission parameters and mode field intensity are calculated by multipole method. The results show the fiber has high nonlinear coefficient, widely flattened chromatic dispersion, low confinement loss together with a single mode operation in the mid-IR range. It has two zero-dispersion wavelengths(ZDWs) at 2.2 μm and 3.32 μm. The supercontinuum generation in fiber is studied by a split-step Fourier numerical stimulation method. We find the pulse with pump pulse width of 100 fs and peak power of 100 W, can generate the mid-IR supercontinuum spectrum covering 1.5～5.5 μm, bu the energy of pump single pulse is only 10 pJ. Soliton self-frequency shift and dispersion wave amplification are the major reasons for supercontinuum generation in fiber..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 20601 (2011)
Holography
Optoelectronic Reconstruction of Three-Dimensional Scenes Based on Multiple Fractional-Fourier-Transform Holograms
Zheng Huadong, Dai Linmao, Wang Tao, and Yu Yingjie
Optoelectronic reconstruction experiment is carried out for holographic display of three-dimensional (3D) scene based on multiple fractional Fourier transform (FrFT). By setting different fractional orders according to different diffraction distances, multiple fractional Fourier transform in each object plane is calculOptoelectronic reconstruction experiment is carried out for holographic display of three-dimensional (3D) scene based on multiple fractional Fourier transform (FrFT). By setting different fractional orders according to different diffraction distances, multiple fractional Fourier transform in each object plane is calculated and superposed to the whole complex amplitude. The amplitude-type and phase-type holograms are obtained by encoding the whole complex amplitude in hologram plane. In order to suppress the speckle noise, a pseudorandom phase factor is added to object planes in calculating sequential holograms. An experimental system is set up for optoelectronic reconstruction based on phase-type liquid crystal spatial light modulator (LC-SLM). Speckle index and correlation coefficient between the reconstructed images from single hologram and sequential holograms are analyzed. The experimental results show that, by calculating sequential holograms of 3D object and reconstructing with phase-type LC-SLM , the speckle noise and conjugate image can be well suppressed and the quality of reconstructed image is improved significantly..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 20901 (2011)
Imaging Systems
Line Spread Function Algorithm Research Based on Geometrical Projection
Xie Wei, Hou Liwei, Xu Chun, and Pan Ming
The line spread function (LSF) testing is the most important part of image quality assessment of optical imaging system. The measuring precision of LSF straightly affects the modulated transfer function (MTF) curve of system. A LSF testing algorithm based on geometrical projection is proposed to raise measuring precisiThe line spread function (LSF) testing is the most important part of image quality assessment of optical imaging system. The measuring precision of LSF straightly affects the modulated transfer function (MTF) curve of system. A LSF testing algorithm based on geometrical projection is proposed to raise measuring precision. The LSF fitting curve is gained by analyzing the algorithm, cutting region of interest (ROI), identifying narrow slit and computing projection. The algorithm is validated by imaging narrow slit with background of a blackbody using a medium wave infrared detector. The results are compared with that using traditional way. The impact of un-uniformity noise on measuring results is analyzed. The main error of the algorithm is analyzed. It is concluded that the algorithm raises the measuring precision and the main factor of measuring error is the signal to noise ratio (SNR) of imaging system..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 21101 (2011)
Integrated Optics
Loss Measurement of Small-Size Silicon-on-Insulator Ridge Waveguide
Liu Jun, Yuan Xiaodong, Luo Zhang, Guo Chucai, and Ye Weimin
A loss measurement method on silicon-on-insulator (SOI) waveguide is proposed on the basis of Fabry-Perot (F-P) cavity theory. Through end coupling, the method utilizes the Fourier transform information of the reflection power spectrum to achieve the waveguide loss measurement. In the process of derivation, the main reA loss measurement method on silicon-on-insulator (SOI) waveguide is proposed on the basis of Fabry-Perot (F-P) cavity theory. Through end coupling, the method utilizes the Fourier transform information of the reflection power spectrum to achieve the waveguide loss measurement. In the process of derivation, the main reason why the loss index can not be directly solved from the peak and valley values of the F-P peaks of reflection spectrum is presented. In the experiment, the loss measurement on a SOI ridge waveguide with an etching depth of 750 nm and a width of 1200 nm is achieved by using the method, which indicates that the method can be used for the loss measurement on small size low-loss waveguides with a relatively high accuracy..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 21301 (2011)
Medical Optics and Biotechnology
Red Blood Cells in Patients with Arrhythmias Using Optical Tweezers Raman Spectroscopy
Wu Zhihui, Mo Hua, Huang Daizheng, and Chen Chaowang
Using optical tweezers Raman spectroscopy system to test and compare the Raman spectra of red blood cells (RBCs) between normal human and arrhythmia patients, we find that the overall intensity of some spectral lines of arrhythmia patients becomes weaker, several lines have a displacement, and the low intensity He-Ne lUsing optical tweezers Raman spectroscopy system to test and compare the Raman spectra of red blood cells (RBCs) between normal human and arrhythmia patients, we find that the overall intensity of some spectral lines of arrhythmia patients becomes weaker, several lines have a displacement, and the low intensity He-Ne laser irradiation has a certain impact on arrhythmia patients red blood cells. According to the diversity of Raman spectra, we further research the changes of the contents in red blood cells and its variation mechanism, and understand the changes of red blood cells′ molecular structure, conformation and composition in different types of arrhythmia disease, and also investigate the pathogenesis of arrhythmia disease by the molecular level..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 21701 (2011)
Optical Clearing Effects Caused by Glycerol Based on Tissue-Simulating Phantoms
Jiang Jingying, Chen Wei, and Xu Kexin
In order to describe optical clearing effects of glycerol quantitatively, tissue-simulating phantoms whose optical properties are identical with that of human skin tissue are introduced. The optical clearing effects of tissue-simulating phantoms with different concentrations of glycerol have been studied by using doublIn order to describe optical clearing effects of glycerol quantitatively, tissue-simulating phantoms whose optical properties are identical with that of human skin tissue are introduced. The optical clearing effects of tissue-simulating phantoms with different concentrations of glycerol have been studied by using double integrating spheres system and Fourier transform-infrared (FT-IR) spectrophotometer. The results show that the scattering coefficients of skin phantoms decrease with the rising glycerol concentration at the wavelength of 632.8 nm, and the light penetration depth increases and the maximum percentage attains to 48.76%. Meanwhile, with the increase of glycerol concentration, the transmittance of skin phantoms increases as well, which equales the reduction of total attenuation coefficients. Therefore, the correlation can be obtained quantitatively between the optical clearing effects induced by glycerol and its concentration in tissue-simulating phantoms..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 21702 (2011)
Mono-Hepatocellular Carcinoma by Raman Mapping
Meng Lingjing, Ji Xiaolu, Li Zida, Liu Junxian, Li Lei, and Yao Huilu
Raman mapping technique is applied to detect mono-hepatocellular carcinoma. The area of characteristic peak at 786, 1450 and 1658 cm-1, which assigns to DNA, lipid and protein, is calculated. According to normalized values image in the corresponding scan location of the cells, the distribution of Raman characteristic pRaman mapping technique is applied to detect mono-hepatocellular carcinoma. The area of characteristic peak at 786, 1450 and 1658 cm-1, which assigns to DNA, lipid and protein, is calculated. According to normalized values image in the corresponding scan location of the cells, the distribution of Raman characteristic peak of these materials in liver cell is reconstructed. The results show that, the distribution of DNA, lipid and protein is exhibited clearly by this Raman mapping system, and the reliability is validated by fluorescence staining. The micro distribution of material in the cells can be confirmed by the imaging of characteristic peak, which provides reliable evidence for Raman detection and liver cancer diagnosis..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 21703 (2011)
Optical Design and Fabrication
Freeform LED Lens Design Based on Longitude-Latitude Division and Tangent-Plane Iteration
Yan Xingtao, Yang Jianfeng, Zhang Guoqi, Ma Xiaolong, Liang Shitong, Cao Jie, and Zhang Lei
According to non-imaging optical principle, a method to obtain freeform based on longitude-latitude division and tangent-plane iteration was proposed. Firstly, a relative position model was constructed in three dimensional coordinate system, and the freeform was divided along its longitude and latitude direction with uAccording to non-imaging optical principle, a method to obtain freeform based on longitude-latitude division and tangent-plane iteration was proposed. Firstly, a relative position model was constructed in three dimensional coordinate system, and the freeform was divided along its longitude and latitude direction with uniform angel. Secondly, because the energy of both each longitude and latitude freeform micro-belt and each corresponding micro-belt on the target plane was equal, the target plane was divided into grids and each coordinates of corresponding points on the target plane were obtained accurately. Finally, by choosing an initial grid node on the freeform, and using Snell equation and tangent-plane iterative method, the coordinates of all grid nodes on the freeform were obtained, which could be synthesized for the freeform surface. The simulation using the designed LED lens shows that for the axial symmetry target plane with uniform illumination, the corresponding optical system can be obtained quickly and accurately with this method, which enables LED light source to be applied in road lighting system..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 22201 (2011)
Design of Optical Lens for Traffic Surveillance System
Zhang Shanhua, Chen Huifang, Zhang Haiting, and Tian Weijian
The design of a wide-band and large-aperture optical lens for traffic surveillance system is presented. By utilizing the atmospheric window of infrared light, clear images are achieved in the dark or poor visibility conditions. To use near-infrared and visible light to image, the charge coupled device (CCD) is adopted The design of a wide-band and large-aperture optical lens for traffic surveillance system is presented. By utilizing the atmospheric window of infrared light, clear images are achieved in the dark or poor visibility conditions. To use near-infrared and visible light to image, the charge coupled device (CCD) is adopted as the image sensor of the lens with pixel size of 4.65 μm and limiting resolution of 110 lp/mm. F-number of the lens is 1.6, the field of view (FOV) is 16.8°, the center wavelength is 880 nm and the operating wavelength range is from 400 nm to 1000 nm. After calculating the parameters of optical lens, Sunnah type is selected as the initial structure. Through optimization, the lens has an excellent imaging performance. The modulation transfer function (MTF) is more than 0.3 at the spatial frequency of 110 lp/mm, and the maximum distortion is less than 0.1%..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 22202 (2011)
Quantum Optics
Squeezing Properties of Atomic Laser in Two-Mode Squeezed Field Interaction with Bose-Einstein Condensate of Two-Level Atoms
Wang Lei, and Sun Changyong
The squeezing properties of atomic laser are studied in two-mode squeezed field interaction with Bose-Einstein condensate (BEC) of two-level atoms within rotating-wave approximation by solving the Heisenberg equation and based on the entire quantum theory. The influence of the interaction among atoms in BEC and the couThe squeezing properties of atomic laser are studied in two-mode squeezed field interaction with Bose-Einstein condensate (BEC) of two-level atoms within rotating-wave approximation by solving the Heisenberg equation and based on the entire quantum theory. The influence of the interaction among atoms in BEC and the coupling constant between light field and atoms on the depth and duration of squeezing is investigated. The results show that two quadrature components of atomic laser can be squeezed periodically. The duration of squeezing atomic laser depends closely on both the interaction among atoms in BEC and the coupling constant between light field and atoms. The depth of squeezing atomic laser is determined by both the interaction among atoms and the initial squeezing factor of light..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 22701 (2011)
Remote Sensing and Sensors
Threshold Amendment and Time-Delay Compensation of Rotational Raman Lidar for Atmospheric Temperature Measurement
Kong Weiguo, Chen Siying, Zhang Yinchao, Chen He, Qiu Zongjia, Wang Yuzhao, Liu Peng, and Ni Guoqiang
Differences exist among the trigger channel and two count channels of multiscaler, which is an essential component of the rotational Raman lidar system for atmospheric temperature measurement, both in the threshold and time-delay aspects, and they will impact the temperature measurement results. A measuring system is eDifferences exist among the trigger channel and two count channels of multiscaler, which is an essential component of the rotational Raman lidar system for atmospheric temperature measurement, both in the threshold and time-delay aspects, and they will impact the temperature measurement results. A measuring system is established for the threshold differences, based on the working principle of the multiscaler and the voltage fluctuation of square waves. In the measuring system, square waves with different voltage values are input to the two count channels successively. Through changing the set threshold value, the count value will be at the peak under a particular set threshold value. By this way, pairs of respective set threshold values of the two count channels corresponding to the same input square wave can be obtained, and furthermore the threshold curves can be fitted. One more measuring system is established for the time-delay differences, and the method for compensating the differences is also proposed. Analysis shows that with the threshold value set according to the fitted curves, the appropriate thresholds can be set more quickly, and the positioning accuracy of atmospheric temperature profile can be improved by about 10 m with the time-delay differences compensated..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 22801 (2011)
Measurement of Linear Frequency-Modulated Continnous-Wave Laser Radar
Zeng Zhaoyang, Zhang Xiaoyong, and Jia Xin
Since the corresponding rate of the photoelectric devices is limited and the laser radar needs to meet the requirements of higher distance resolution, linear frequency-modulated continuous-wave (LFMCW) laser radar′s relative bandwidth has to be larger than that of the microwave radar. The measuring theory of LFMCW micrSince the corresponding rate of the photoelectric devices is limited and the laser radar needs to meet the requirements of higher distance resolution, linear frequency-modulated continuous-wave (LFMCW) laser radar′s relative bandwidth has to be larger than that of the microwave radar. The measuring theory of LFMCW microwave radar′s distance and velocity of moving targets cannot be applied directly to the laser radar. In order to detect the short-range high-speed moving target in real-time, a fast linear frequency modulated signal parameters estimation algorithm is proposed, according to the echo′s characteristics of laser radar target. This algorithm divides the IF signal into two sections symmetrically, then carries out Fourier transform of the IF signal to get the target′s distance and speed information. If the target distance is 50 m, speed is 1000 m/s, and IF signal to noise ratio (SNR) is 0, the radar′s ranging error is less than 15 mm and velocity error is less than 10 m/s. Results of simulation experiment show that the algorithm has high measuring precision and strong anti-jamming capability..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 22802 (2011)
Scattering
Calculation of Single Scattering Parameters in Vector Radiative Transfer Equation
Wang Haihua, Sun Xianming, Liu Wanqiang, Shen Jin, and Liu Wei
Based on Mie theory, the single scattering characteristics of a cluster of polydisperse spherical aerosols are calculated. The size distribution of particles is Gamma distribution and effective radii are 5.56, 7, 11 μm, respectively. The average extinction coefficients, average scattering coefficients, single scatterinBased on Mie theory, the single scattering characteristics of a cluster of polydisperse spherical aerosols are calculated. The size distribution of particles is Gamma distribution and effective radii are 5.56, 7, 11 μm, respectively. The average extinction coefficients, average scattering coefficients, single scattering albedos, asymmetry parameters and elements of single scattering phase matrix in the spectral range of 0.4～100 μm are analyzed. The numerical results show that the single scattering properties of aerosols are seldom affected by particle effective radius in visual light waveband, but greater at higher waveband. The single scattering albedo approximately equals 1 at visual light waveband and the characteristics of single scattering albedo are opposite to the imagery part of refraction index. The polarization ratios of single scattering phase matrix are more sensitive to particle size than phase functions..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 22901 (2011)
Spectroscopy
Soil Moisture Measurement Based on Terahertz Transmission Spectrum
Xia Jiaxin, Fan Chengfa, Wang Kejia, and Liu Jinsong
Liquid water is a kind of polar liquid, and has a strong absorption on the terahertz wave. The tiny change of soil moisture has a great influence on the transmitted terahertz wave. Accordingly, a method is proposed to measure the soil moisture based on time domain terahertz transmission spectrum. Soil terahertz parametLiquid water is a kind of polar liquid, and has a strong absorption on the terahertz wave. The tiny change of soil moisture has a great influence on the transmitted terahertz wave. Accordingly, a method is proposed to measure the soil moisture based on time domain terahertz transmission spectrum. Soil terahertz parameters concept is proposed and the equations to calculate soil moisture are derived. Abundant results of soil samples are obtained with terahertz time domain spectroscopy, and the preliminary soil terahertz parameter value is given. By comparison with oven drying method, it demonstrates that this method is accurate and available..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 23001 (2011)
Thin Films
Study on Fabrication of Porous Alumina Film on Glass
Zhao Lixin, Xue Yiyu, Guo Peitao, Peng Hua, and Li Zhanwang
Porous alumina optical film with controllable pore diameter, porosity and highly ordered pore arrangement is fabricated on B207 optical glass by electron-beam evaporation and anodic oxidation. The surface morphology and transmittance of the film are examined by scanning electron microscope (SEM) and the spectrophotometPorous alumina optical film with controllable pore diameter, porosity and highly ordered pore arrangement is fabricated on B207 optical glass by electron-beam evaporation and anodic oxidation. The surface morphology and transmittance of the film are examined by scanning electron microscope (SEM) and the spectrophotometer, respectively. The results indicate that the surface quality of electron-beam-evaporated aluminum film is much worse than that of electrochemically polished Al foil. A two-step anodization can improve the surface quality compared with the one-step anodization. Compared with sulfuric acid and oxalic acid solutions, porous anodic alumina film prepared by electrochemically anodizing in phosphoric acid solutions has larger pore diameter and higher porosity. The transmittance of porous anodic alumina film increases after annealing..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 23101 (2011)
Design and Research on Tricolor Micro-Optical Guidepipe Used in Backlight Module
Xie Hongbo, Yu Honglang, Gong Renmin, Han Lin, and Li Tao
A side-emitting micro-optical guidepipe is presented to replace the linear light source cold cathode fluorescent lighting (CCFL) in backlight module . The guidepipe retains the advantages of designing the light guide plate but avoid the shortcomings of CCFL. Combined with RGB LED, the new backlight module can realize tA side-emitting micro-optical guidepipe is presented to replace the linear light source cold cathode fluorescent lighting (CCFL) in backlight module . The guidepipe retains the advantages of designing the light guide plate but avoid the shortcomings of CCFL. Combined with RGB LED, the new backlight module can realize time mixing color and remove color filter. The tricolor micro-optical guidepipe is modeled in optical software, and the netted dots radius function is proposed by theoretical derivation to uniform light energy, then the analysis show that the structure improves color range to 150%, the efficiency is above 66% the uniformity is better than 95%, and the light transmittance of this new backlight is 12% which is twice of that of the CCFL backlight module..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 23102 (2011)
Effect of N, N-Dimethylformamide on Structure and Optical Properties of Porous Silica Film
Peng Hua, Xia Zhilin, Xue Yiyu, Guo Peitao, Fu Zhiwei, and Zhao Lixin
Using a base catalysis for the hydrolysis of tetraethyl orthosilicate (TEOS), porous silica antireflective film are prepared by in-situ sol-gel process and normal atmosphere drying with the introduction of N, N-dimethylformamide (DMF). Thermal stability in drying process of the SiO2 sol is studied by Netzsch thermal anUsing a base catalysis for the hydrolysis of tetraethyl orthosilicate (TEOS), porous silica antireflective film are prepared by in-situ sol-gel process and normal atmosphere drying with the introduction of N, N-dimethylformamide (DMF). Thermal stability in drying process of the SiO2 sol is studied by Netzsch thermal analyzer; the structure and morphology of these samples are characterized by scanning electron microscope (SEM); the effect on optical properties of porous silicon thin films are measured by spectrophotometer. The results show that DMF effectively prevents the gel from cracking and inhibits the formation of particle clusters, which makes silica particles form a network and prepare silica films easily. DMF can also improve the transmittance of film higher than 99% in 300~1000 nm region..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 2, 23103 (2011)
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