Journals >Infrared and Laser Engineering
Contents
2004
Volume: 33 Issue 3
27 Article(s)
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Research Article
Study of microsphere extinction efficiency by Matlab language computer simulation
[in Chinese], and [in Chinese]
The mathematical character of the extinction efficiency (normalized extinction cross section) is analysed and the numerical computation by Matlab language computer simulation is studied. The relationships between the ripple structure of the extinction efficiency and the size parameter x, the peak value of the ripple stThe mathematical character of the extinction efficiency (normalized extinction cross section) is analysed and the numerical computation by Matlab language computer simulation is studied. The relationships between the ripple structure of the extinction efficiency and the size parameter x, the peak value of the ripple structure and the amplitude of Mie scattering a_n(x,m), b_n(x,m) are discussed. The relationship between the approximate periodicity of the ripple structure and relative refractive index m is also discussed. The result shows that the relation curve of the extinction efficiency and the size parameter x has ripple structure, which becomes faint as x is large;when the relative index m is real and m≤2, the ripple structure has single periodicity, and positions of the peak values of the ripple structure are corresponding to the positions of peak values of Re[a_n(x,m)]and Re[b_n(x,m)]. When m is complex and ｜Im(m)｜<0.01,the ripple structure also has the same periodicity,however, the oscillation amplitude of the ripple structure becomes weaker. The larger | Im( m) | is , the weaker the oscillation amplitude of the ripple structure is. The computer simulation results of this paper can provide reference for further study of microsphere..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 231 (2004)
Research on laser atmospheric propagation in low elevation on the sea
[in Chinese], [in Chinese], and [in Chinese]
Aiming at the key problems of laser weapon, laser atmospheric propagation property in low elevation on the sea is researched. Firstly, laser atmospheric propagation property on the sea is analyzed, and atmospheric transmittance of 1.06 μm laser in low elevation is calculated. And then high power laser atmospheric propaAiming at the key problems of laser weapon, laser atmospheric propagation property in low elevation on the sea is researched. Firstly, laser atmospheric propagation property on the sea is analyzed, and atmospheric transmittance of 1.06 μm laser in low elevation is calculated. And then high power laser atmospheric propagation is qualitatively analyzed. In addition, the compensation technology of laser atmospheric propagation is given. Finally, some data and conclusions about 1.06 μm laser atmospheric propagation in low elevation on the sea are presented. It has some extent reference values for research on laser weapon..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 235 (2004)
Detecting of small infrared moving object based on dynamic programming algorithm
[in Chinese], [in Chinese], and [in Chinese]
An update dynamic programming algorithm is presented in allusion to the features of small moving object.Using the sum of grey level in image sequences, the target is brought into prominence and noise is suppressed by the image preprocessing at the same time. The probability of detecting and false alarm are used to deteAn update dynamic programming algorithm is presented in allusion to the features of small moving object.Using the sum of grey level in image sequences, the target is brought into prominence and noise is suppressed by the image preprocessing at the same time. The probability of detecting and false alarm are used to determine the threshold of image, which can abstract the small target accurately. And dynamic programming algorithm performs well in detecting, and it lays foundations for the tracking in the next step..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 303 (2004)
Detection method for dim small IR targets based on mathematical morphology
[in Chinese], [in Chinese], and [in Chinese]
A new detection method for moving dim small targets in infrared image sequences is presented. Firstly, the proposed method suppresses the background clutter with mathematical morphology and median filtering in temporal profile of image sequences, then segments the candidate target from background. Finally, the continuiA new detection method for moving dim small targets in infrared image sequences is presented. Firstly, the proposed method suppresses the background clutter with mathematical morphology and median filtering in temporal profile of image sequences, then segments the candidate target from background. Finally, the continuity of moving and the consistency of track of the target in sequential images are used to identify the real target. The experimental result shows the effectiveness of the proposed method..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 307 (2004)
Hybrid RBF training algorithm based on artificial immunology
[in Chinese], [in Chinese], and [in Chinese]
Based on artificial immune clustering and Immune Evolutionary Algorithm (IEA), a novel hybrid RBF design method is proposed. The artificial immune clustering is used to adaptively specify the amount and initial position of centers of basis functions in RBF network according to input data set. Then immune evolutionary aBased on artificial immune clustering and Immune Evolutionary Algorithm (IEA), a novel hybrid RBF design method is proposed. The artificial immune clustering is used to adaptively specify the amount and initial position of centers of basis functions in RBF network according to input data set. Then immune evolutionary algorithm is used to train the RBF network, which reduces the searching space of canonical evolutionary algorithm and improves the convergence speed. Computer simulations demonstrate that the RBF network designed in this method has a concise structure with good generalization ability..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 311 (2004)
Off-axis illumination system design for projection display
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel off-axis illumination system has been developed to collect and focus light from an arc lamp onto the imager. The system consists of a sphere-ellipsoidal reflector, a hyperboloidal reflector and a tilted light pipe. The sphere-ellipsoidal reflector synthesizes two main light beams and focuses the light to reduceA novel off-axis illumination system has been developed to collect and focus light from an arc lamp onto the imager. The system consists of a sphere-ellipsoidal reflector, a hyperboloidal reflector and a tilted light pipe. The sphere-ellipsoidal reflector synthesizes two main light beams and focuses the light to reduce the entendue value. The hyperboloidal reflector transforms the shape of beam into a tilted light pipe to gain high collection efficiency and uniformity. The modeling result obtained by LightTools and ZEMAX shows that the system can illuminate the small imagers with high uniformity and collection efficiency..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 316 (2004)
Photonic crystal and it's applications
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Photonic crystals are a new kind of materials with photonic bandgap, their unique physical features bring about a number of theory research and wide application prospect. The basical conception of photonic crystals and fabrication methods of three dimensional photonic crystals are introduced, and some characters and apPhotonic crystals are a new kind of materials with photonic bandgap, their unique physical features bring about a number of theory research and wide application prospect. The basical conception of photonic crystals and fabrication methods of three dimensional photonic crystals are introduced, and some characters and applications in optics, communications and microwave etc are summarized..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 320 (2004)
Research on copying system of a large scale multiplex holographic stereograms
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Multiplex rainbow holographic stereograms can record objects with 2D image, 360° cylindrical holographic stereograms can show animated 3D image when it is illuminated with a small white light source. It has wide applications and exploitation potential in many fields. To meet the needs of market, the duplicator of Multiplex rainbow holographic stereograms can record objects with 2D image, 360° cylindrical holographic stereograms can show animated 3D image when it is illuminated with a small white light source. It has wide applications and exploitation potential in many fields. To meet the needs of market, the duplicator of multiplex holographic stereograms and the silver halide holographic film that is adaptable to the copying system of the multiplex holographic stereograms are developed. The light intensity distribution of the multiplex hologram surface and the rainbow hologram suface at reconstruction are analyzed.Using the developed halide silver holographic film, a 360° cylindrical holographic stereograms is copied. Its noise is very low and the diffraction effect is obviously higher than that of the multiplex holographic stereograms copied by the sensitive holographic films. The efficiency of batch manufacturing of the multiplex holographic stereograms increase to several tenfolds..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 323 (2004)
Technique of wavelength demultiplexing with dense multiple volume holographic grating
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The principle of wavelength demultiplexing with multiple volume holographic grating filter is described. The selectivity of its wavelength and angle is analyzed and the wavelength spacing is discussed. One scheme of wavelength demultiplexing with multiple volume holographic grating filter and the technique difficultiesThe principle of wavelength demultiplexing with multiple volume holographic grating filter is described. The selectivity of its wavelength and angle is analyzed and the wavelength spacing is discussed. One scheme of wavelength demultiplexing with multiple volume holographic grating filter and the technique difficulties to be resolved while being put into practice are put forward..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 327 (2004)
[in Chinese]
Novel infrared-sensitive streak image tube
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel infrared-sensitive streak image tube with a combined infrared photocathode and electrostatics focused electronic optical system is described. Using the characteristics of electron trapping material(ETM) for the rapid infrared up-conversion, a kind of combined infrared photocathode is made by coupling ETM-based A novel infrared-sensitive streak image tube with a combined infrared photocathode and electrostatics focused electronic optical system is described. Using the characteristics of electron trapping material(ETM) for the rapid infrared up-conversion, a kind of combined infrared photocathode is made by coupling ETM-based infrared up-conversion screen with visible photocathode. The novel infrared-sensitive streak image tube is able to extend spectral sensitivity to 800～1600 nm.The peak value of the converting efficiency is located at 1165 nm. Time resolution is superior to 15 ps..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 221 (2004)
Research on far IR shielding effect of multi-material
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The problem of IR absorption and the way how to optimize far IR smokescreen are described. Based on particles dispersion theory, the dispersion of one material particle is calculated. Then the relationship between transmissivity and diameter of some materials is analyzed. For each material, the minimum transmissivity vThe problem of IR absorption and the way how to optimize far IR smokescreen are described. Based on particles dispersion theory, the dispersion of one material particle is calculated. Then the relationship between transmissivity and diameter of some materials is analyzed. For each material, the minimum transmissivity value is obtained. Finally, the IR absorption spectrum of the smokescreen is given and the result is satisfactory..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 224 (2004)
Current status and applications of infrared thermography
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The main characteristics of IR thermography on temperature measurement and the development of infrared thermographic equipments are discussed. Applications of IR thermographic techniques on NDT&E of materials and structures, thermal diagnosis of equipments, testing of structures and buildings, and prevention and cuThe main characteristics of IR thermography on temperature measurement and the development of infrared thermographic equipments are discussed. Applications of IR thermographic techniques on NDT&E of materials and structures, thermal diagnosis of equipments, testing of structures and buildings, and prevention and cure of disasters are reviewed. The application prospect of IR thermography is expected..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 227 (2004)
[in Chinese]
Retrieval of atmosphere extinction coefficient for imaging laser radar
[in Chinese], [in Chinese], and [in Chinese]
The atmosphere extinction coefficient for the application of imaging laser radar is solved by Klett iteration method. The Monte-Carlo simulated results for typical conditions of the imaging laser radar operation show that the theoretical error of the extinction coefficient is less than 6%. The fluctuation of the extincThe atmosphere extinction coefficient for the application of imaging laser radar is solved by Klett iteration method. The Monte-Carlo simulated results for typical conditions of the imaging laser radar operation show that the theoretical error of the extinction coefficient is less than 6%. The fluctuation of the extinction coefficient affected by the atmospheric scintillation is obvious, but the variation trend is coincident with the theoretical model..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 239 (2004)
Atmospheric effects on the link near the earth of optical wireless communication
[in Chinese], and [in Chinese]
Optical wireless communication has several advantages.It has become a viable tool to solve "last-mile" and been considered one of development direction of the next generation optical communication.The history of the development of the optical wireless communication is reviewed firstly, and then, the atmospherOptical wireless communication has several advantages.It has become a viable tool to solve "last-mile" and been considered one of development direction of the next generation optical communication.The history of the development of the optical wireless communication is reviewed firstly, and then, the atmospheric effects to the laser wireless communication link near the earth are elaberated and the emphasis is the atmospheric degradations and turbidity effects. Finally, the scintillation is simulated and the future is forecasted..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 243 (2004)
Laser fuze design for ballistic missile
[in Chinese], [in Chinese], and [in Chinese]
Ballistic missile's laser fuze is used to control warhead's blasting height. Battle environment for ballistic missile is complicated and tactical request is strict, so laser fuze equipped for it needs some special indices, such as high repetition rate, long ranging, etc. So a laser fuze scheme for ballistic misBallistic missile's laser fuze is used to control warhead's blasting height. Battle environment for ballistic missile is complicated and tactical request is strict, so laser fuze equipped for it needs some special indices, such as high repetition rate, long ranging, etc. So a laser fuze scheme for ballistic missile is designed applying multiple advanced technologies, including Diode-Pumped Solid-State Laser(DPSSL), high sensitive detecting component, optimal background suppression, signal processing with anti-interference and target recogniting. The designed laser fuze has small size and weight, fine performance of anti-interference and high ranging precision. So the laser fuze can perfectly fulfill the request for ballistic missile's blasting height control..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 248 (2004)
Long distance microvibration measurement using external-cavity semiconductor laser
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
With Littrow-type external-cavity grating and temperature controlling, the spectral line width is compressed to be less than 1.2 MHz (Δλ<3.5×10~(-6) nm), while the original linewidth of the semiconductor laser is broader than 1200 GHz. Based on this, the system for measuring the amplitude and frequency of the mWith Littrow-type external-cavity grating and temperature controlling, the spectral line width is compressed to be less than 1.2 MHz (Δλ<3.5×10~(-6) nm), while the original linewidth of the semiconductor laser is broader than 1200 GHz. Based on this, the system for measuring the amplitude and frequency of the microvibration with sinusoidal modulation is designed, detecting effect is good..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 253 (2004)
Analysis about the invalidation and improvement research of semiconductor saturable absorption mirror
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The modelocking principle and the manufacture method of semiconductor saturable absorption mirror are introduced. By analyzing the behavior that ultrashort pulse acts on semiconductor material, some methods to increase the anti-damage threshold are put forward, such as doping in absorption layer, annealing, widening thThe modelocking principle and the manufacture method of semiconductor saturable absorption mirror are introduced. By analyzing the behavior that ultrashort pulse acts on semiconductor material, some methods to increase the anti-damage threshold are put forward, such as doping in absorption layer, annealing, widening the area grown at low temperature, surface heat sink and so on. In experiment, several semiconductor saturable absorption mirrors could work and obtain stable passive modelocking pulse output after annealing and being coated with dielectric film..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 256 (2004)
Research on basic wave of laser imaging for earth observation
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The concept of basic wave of laser return in laser imaging for earth observation is put forward. Its important meaning is discussed. And the method of getting the basic wave is also given. According to the experiment, a series of laser return are digitized and the basic wave is acquired after processing. At last, the bThe concept of basic wave of laser return in laser imaging for earth observation is put forward. Its important meaning is discussed. And the method of getting the basic wave is also given. According to the experiment, a series of laser return are digitized and the basic wave is acquired after processing. At last, the basic wave is analyzed and its application is discussed..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 260 (2004)
Research on performances of LPCS with different lamphouses
[in Chinese], [in Chinese], and [in Chinese]
Light intensity distributions of two typical lamp-houses used in Laser Particle Counter System (LPCS)——He-Ne laser and semiconductor laser are measured by Beam Pro_(file)2350. According to the results, intensity uniformity of sensitive volumes formed by two lamp-houses respectively is analyzed. Using the LPCS, the partLight intensity distributions of two typical lamp-houses used in Laser Particle Counter System (LPCS)——He-Ne laser and semiconductor laser are measured by Beam Pro_(file)2350. According to the results, intensity uniformity of sensitive volumes formed by two lamp-houses respectively is analyzed. Using the LPCS, the particle size distributions of the normal particles are measured and corresponding counting efficiency and distinguishability are calculated. The results indicate that intensity uniformity of sensitive volume formed by semiconductor laser is better than that formed by He-Ne laser, and correspondingly, the former has better counting efficiency and distinguishability. By comparision with using He-Ne laser, LPCS using semiconductor laser can make its distinguishability of particle diameters increase 17%..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 264 (2004)
Optimizing control of laser surface strengthening parameters for processing 20CrMo steel based on BP neural network
[in Chinese], and [in Chinese]
Research and optimizing on laser strengthening processing and controlling for processing 20CrMo alloy structure steel by taking laser power, laser processing beam diameter, laser scanning velocity as input parameters and non-transformation hardening, transformation hardening, melting as output parameters. BP neural netResearch and optimizing on laser strengthening processing and controlling for processing 20CrMo alloy structure steel by taking laser power, laser processing beam diameter, laser scanning velocity as input parameters and non-transformation hardening, transformation hardening, melting as output parameters. BP neural network of processing optimal model between laser processing parameters and material surface strengthened quality is established by comparing experimental results and computering simulation analytic results. It is shown that laser processing parameters can be chosen conveniently and material surface quality can be controlled effectively by using BP neural network, furthermore, the proposed model provides accurate results for processing, and fits the experimental results well..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 269 (2004)
Laser cleaning technology and its applications
[in Chinese], and [in Chinese]
A new material processing technology of laser cleaning is introduced. Its merit, mechanisms and types are all elaborated, the influence of laser power density, pulse number, incident angle and wavelength are also analyzed. Furthermore, some application examples of laser cleaning are introduced, and the results indicateA new material processing technology of laser cleaning is introduced. Its merit, mechanisms and types are all elaborated, the influence of laser power density, pulse number, incident angle and wavelength are also analyzed. Furthermore, some application examples of laser cleaning are introduced, and the results indicate that the cleaning effect is satisfying..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 274 (2004)
[in Chinese]
Speckle noise pre-processing technology on image captured at night for pattern matching
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The real-time images captured at night in pattern matching are usually corrupted by speckle noise, which depresses the matching performance. In order to suppress the influence of speckle noise to pattern matching, a new method has been proposed in the paper. The speckle noise is marked and then is out of correlation stThe real-time images captured at night in pattern matching are usually corrupted by speckle noise, which depresses the matching performance. In order to suppress the influence of speckle noise to pattern matching, a new method has been proposed in the paper. The speckle noise is marked and then is out of correlation statistics in pattern matching. Compared with the most popular algorithms, such as median filtering and the average filtering, this method is more efficient for pattern matching. Experimental results show that this method is available..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 278 (2004)
Real-time infrared image enhancing algorithm easy to implement
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Commonly used image enhancing algorithm is analyzed based on the character of infrared image, and a infrared image enhancing algorithm using plateau histograph and enhanced high-pass filtering is also put forward. This algorithm which is easy to implement using FPGA has excellent image enhancing and real-time performanCommonly used image enhancing algorithm is analyzed based on the character of infrared image, and a infrared image enhancing algorithm using plateau histograph and enhanced high-pass filtering is also put forward. This algorithm which is easy to implement using FPGA has excellent image enhancing and real-time performance..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 282 (2004)
Study on thresholding segmentation for infrared image based on edge detection
[in Chinese], [in Chinese], and [in Chinese]
A thresholding segmentation algorithm for complex background is introduced. The method is based on edge detecting of infrared image. Firstly, the image edge is detected, and then segmentation threshold is computed by weighting and averaging value of pixels gray. The method is simple and practical, and it can segment thA thresholding segmentation algorithm for complex background is introduced. The method is based on edge detecting of infrared image. Firstly, the image edge is detected, and then segmentation threshold is computed by weighting and averaging value of pixels gray. The method is simple and practical, and it can segment the targets in the air and on the sea exactly. And it has been used in tracking system, the experimental result indicates that the algorithm is correct and real-time, and the system is reliable..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 288 (2004)
Study on infrared image processing circuit based on high speed DSP
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A image processing system based on high performance fixed-point Digital Signal Processor (DSP)TMS320C6201 is discussed. This system includes drive circuit module, A/D and D/A transform module, digital signal processing module and video frequency display module. As a result of using high performance and low dissipation A image processing system based on high performance fixed-point Digital Signal Processor (DSP)TMS320C6201 is discussed. This system includes drive circuit module, A/D and D/A transform module, digital signal processing module and video frequency display module. As a result of using high performance and low dissipation processing chip, the system owns the virtues of high real-time, performance stability, high precision, small bulk and low dissipation, and has wide application in the future..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 292 (2004)
Research on time-frequency feature extraction based on energy
[in Chinese], [in Chinese], and [in Chinese]
The important basis on the classification and target recognization of nonstationary signal is how to effectively extract feature from it in the gaussian white noise ambience. The watershed algorithm is used to segment the time-frequency distribution of a signal and combine segmentations according energy maximum criteriThe important basis on the classification and target recognization of nonstationary signal is how to effectively extract feature from it in the gaussian white noise ambience. The watershed algorithm is used to segment the time-frequency distribution of a signal and combine segmentations according energy maximum criterion, then a feature extraction method based on energy is proposed. Simulative examples demonstrate that it can effectively extract feature and has a good anti-noise performance to gaussian white noise..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 296 (2004)
Application of Rough Set and K-means clustering in image segmentation
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Rough Set theory is a new mathematical tool to deal with problems on vagueness and uncertainty. An image segmentation method based on Rough Set theory and K-means clustering is presented. The original image is segmented according to the relation of equal value. By applying value reduct to the attribute values, differenRough Set theory is a new mathematical tool to deal with problems on vagueness and uncertainty. An image segmentation method based on Rough Set theory and K-means clustering is presented. The original image is segmented according to the relation of equal value. By applying value reduct to the attribute values, different regions are classified based on indiscernibility. The experimental results indicate that the method can improve veracity and stability of image segmentation..
Infrared and Laser Engineering
- Publication Date: Jun. 01, 2004
- Vol. 33, Issue 3, 300 (2004)
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