2011
2011
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Record 205 of
Title:The third-order optical nonlinearities of Ge-Ga-Sb(In)-S chalcogenide glasses
Author(s):Guo, Haitao(1); Chen, Hongyan(2); Hou, Chaoqi(1); Lin, Aoxiang(1); Zhu, Yonggang(1); Lu, Shoudi(1); Gu, Shaoxuan(2); Lu, Min(1); Peng, Bo(1)Source: Materials Research Bulletin Volume: 46 Issue: 5 DOI: 10.1016/j.materresbull.2010.11.020 Published: May 2011Abstract:The third-order optical nonlinearities of 80GeS2·(20 - x)Ga2S3·xY2S3 (x = 0, 5, 10, 15, 20 and Y = Sb or In) chalcogenide glasses were investigated utilizing the Z-scan method at the wavelength of 800 nm and their linear optical properties and structure were also studied. By analyzing the compositional dependences and possible influencing factors including the linear refractive index, the concentration of lone electron pairs, the optical bandgap and the amount of weak covalent/homopolar bonds, it indicates that the electronic contribution in weak heteropolar covalent and homopolar metallic bonds is responsible for large nonlinear refractive index n2 in the chalcogenide glasses. These chalcogenide glasses have characteristics of environmentally friendship, wide transparency in the visible region, high nonlinear refractive index n 2 and low nonlinear absorption coefficient β, and would be expected to be used in the all-optical switches working at 1330 nm and 1550 nm telecommunication wavelengths. ? 2010 Elsevier Ltd. All rights reserved.Accession Number: 20111313858105 -
Record 206 of
Title:Tunable nonlinear frequency conversion of bismuth-tellurite glass holey fiber
Author(s):Ryasnyanskiy, Aleksandr(1); Lin, Aoxiang(1,2); Guintrand, Cyril(1); Biaggio, Ivan(1); Toulouse, Jean(1)Source: Optics InfoBase Conference Papers Volume: Issue: DOI: 10.1364/ofc.2011.oths2 Published: 2011Abstract:We report on tunable parametric generation (PG) and third-harmonic generation (THG) in a 2.9-μm core bismuth-tellurite holey glass fiber. The maximum conversion efficiency was measured to be 0.1% and 0.06% for PG and THG respectively. ? 2010 Optical Society of America.Accession Number: 20140917383555 -
Record 207 of
Title:Real-time measurement of detonation transient temperature
Author(s):Zheng, Jin-Kun(1,3); Bai, Yong-Lin(2); Wang, Bo(2); Liu, Bai-Yu(2); Yang, Wen-Zheng(2); Bai, Xiao-Hong(2); Qin, Jun-Jun(2); Zhao, Jun-Ping(1); Gou, Yong-Sheng(1); Liu, Hui(1,3)Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 31 Issue: 11 DOI: 10.3964/j.issn.1000-0593(2011)11-3060-05 Published: November 2011Abstract:Based on the spectral characteristic of the detonation temperature, the present paper presents a measurement system of transient multi-wavelength pyrometry with the theory of multi-wavelength thermometry. The FPGA was applied as the hardware developing platform and the high-speed linear CCD was utilized. Each module was controlled by FPGA to achieve the process of real-time data acquisition, storage and transmission. Using the multiple regression analysis method, the dynamic spectral waveforms were calculated. The two laser spectral lines, 630 and 532 nm, were used to calibrate the corresponding pixel sequence numbers and the No.175 and No.270 were confirmed. In this paper, the halide tungsten light was measured. The results show that the system can sample continuous spectrum signal at several different times; the CCD can stably work with 40 MHz clock and the frame scanning frequency can achieve 73 kHz.Accession Number: 20114614524938 -
Record 208 of
Title:Image denoising via improved sparse coding
Author(s):Lu, Xiaoqiang(1); Yuan, Haoliang(2); Yan, Pingkun(1); Yuan, Yuan(1); Li, Luoqing(2); Li, Xuelong(1)Source: BMVC 2011 - Proceedings of the British Machine Vision Conference 2011 Volume: Issue: DOI: 10.5244/C.110.310 Published: 2011Abstract:This paper presents a novel dictionary learning method for image denoising, which removes zero-mean independent identically distributed additive noise from a given image. Choosing noisy image itself to train an over-complete dictionary, the dictionary trained by traditional sparse coding methods contains noise information. Through mathematical derivation of equation, we found that a lower bound of dictionary is related with the level of noise in dictionary learning. The proposed idea is to take advantage of the noise information for designing a sparse coding algorithm called improved sparse coding (ISC), which effectively suppresses the noise influence for training a dictionary. This denoising framework utilizes the effective method, which is based on sparse representations over trained dictionaries. Acquiring an over-complete dictionary by ISC mainly includes three stages. Firstly, we utilize K-means method to group the noisy image patches. Secondly, each dictionary is trained by ISC in corresponding class. Finally, an over-complete dictionary is merged by these dictionaries. Theory analysis and experimental results both demonstrate that the proposed method yields excellent performance. ? 2011. The copyright of this document resides with its authors.Accession Number: 20141617592803 -
Record 209 of
Title:Study on scalable Coulombic degradation for estimating the lifetime of organic light-emitting devices
Author(s):Zhang, Wenwen(1,2); Wu, Zhaoxin(2); Liang, Shixiong(2); Jiao, Bo(2); Zhang, Xinwen(2); Wang, Dawei(2); Hou, Xun(1,2); Chen, Zhijian(3); Q., GongSource: Journal of Physics D: Applied Physics Volume: 44 Issue: 15 DOI: 10.1088/0022-3727/44/15/155103 Published: April 20, 2011Abstract:The luminance decays of organic light-emitting diodes (OLEDs) are investigated with initial luminance of 1000 to 20 000 cd m-2 through a scalable Coulombic degradation and a stretched exponential decay. We found that the estimated lifetime by scalable Coulombic degradation deviates from the experimental results when the OLEDs work with high initial luminance. By measuring the temperature of the device during degradation, we found that the higher device temperatures will lead to instabilities of organic materials in devices, which is expected to result in the difference between the experimental results and estimation using the scalable Coulombic degradation. ? 2011 IOP Publishing Ltd.Accession Number: 20111413897554 -
Record 210 of
Title:A relay level set method for automatic image segmentation
Author(s):Gao, Xinbo(1); Wang, Bin(1); Tao, Dacheng(2); Li, Xuelong(3)Source: IEEE Transactions on Systems, Man, and Cybernetics, Part B: Cybernetics Volume: 41 Issue: 2 DOI: 10.1109/TSMCB.2010.2065800 Published: April 2011Abstract:This paper presents a new image segmentation method that applies an edge-based level set method in a relay fashion. The proposed method segments an image in a series of nested subregions that are automatically created by shrinking the stabilized curves in their previous subregions. The final result is obtained by combining all boundaries detected in these subregions. The proposed method has the following three advantages: 1) It can be automatically executed without humancomputer interactions; 2) it applies the edge-based level set method with relay fashion to detect all boundaries; and 3) it automatically obtains a full segmentation without specifying the number of relays in advance. The comparison experiments illustrate that the proposed method performs better than the representative level set methods, and it can obtain similar or better results compared with other popular segmentation algorithms. ? 2006 IEEE.Accession Number: 20111213849924 -
Record 211 of
Title:Intrinsic images using optimization
Author(s):Shen, Jianbing(1); Yang, Xiaoshan(1); Jia, Yunde(1); Li, Xuelong(2)Source: Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition Volume: Issue: DOI: 10.1109/CVPR.2011.5995507 Published: 2011Abstract:In this paper, we present a novel intrinsic image recovery approach using optimization. Our approach is based on the assumption of color characteristics in a local window in natural images. Our method adopts a premise that neighboring pixels in a local window of a single image having similar intensity values should have similar reflectance values. Thus the intrinsic image decomposition is formulated by optimizing an energy function with adding a weighting constraint to the local image properties. In order to improve the intrinsic image extraction results, we specify local constrain cues by integrating the user strokes in our energy formulation, including constant-reflectance, constant-illumination and fixed-illumination brushes. Our experimental results demonstrate that our approach achieves a better recovery of intrinsic reflectance and illumination components than by previous approaches. ? 2011 IEEE.Accession Number: 20113814348167 -
Record 212 of
Title:Image reconstruction by an alternating minimisation
Author(s):Lu, Xiaoqiang(1); Sun, Yi(1); Yuan, Yuan(2)Source: Neurocomputing Volume: 74 Issue: 5 DOI: 10.1016/j.neucom.2010.08.003 Published: February 2011Abstract:This paper focuses on the problem of incomplete data in the applications of the circular cone-beam computed tomography. This problem is frequently encountered in medical imaging sciences and some other industrial imaging systems. For example, it is crucial when the high density region of objects can only be penetrated by X-rays in a limited angular range. As the projection data are only available in an angular range, the above mentioned incomplete data problem can be attributed to the limited angle problem, which is an ill-posed inverse problem. This paper reports a modified total variation minimisation method to reduce the data insufficiency in tomographic imaging. This proposed method is robust and efficient in the task of reconstruction by showing the convergence of the alternating minimisation method. The results demonstrate that this new reconstruction method brings reasonable performance. ? 2010 Elsevier B.V.Accession Number: 20110113548275 -
Record 213 of
Title:High-repetition-frequency high-voltage narrow pulse source achieved by frequency superposition
Author(s):Zhang, Wei(1,3); Liu, Baiyu(2); Ruan, Chi(2); Bai, Yonglin(2); Ouyang, Xian(2); Gou, Yongsheng(1,3)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 40 Issue: 7 DOI: Published: July 2011Abstract:The traditional method to achieve high-repetition-frequency high-voltage narrow pulsed source is subjected to the device performance, thus the new idea of frequency superposition was put forward. Based on the theories of ultra-fast electronics and frequency superposition, multi-channel high-voltage narrow pulses were produced by MARX circuits. Through the synchronous system, the delay of multi-channel trigger signals were controlled and the multi-channel pulses were coupled into one way to achieve high- repetition-frequency high-voltage narrow pulse output. The two output pulses from the MARX circuits were 2.56 kV in amplitude, 7.13 ns in width and 32 kHz in repetition frequency. While the coupled pulse was 2.46 kV, 7.49 ns and 64 kHz in amplitude, width and repetition frequency, respectively. The idea is confirmed by experimentally superposing frequencies of two pulses with the result of doubled output pulse frequency. This method can be extended to more pulses to obtain higher frequency.Accession Number: 20113614302192 -
Record 214 of
Title:Helium-implanted optical planar waveguides in Nd3+-doped phosphate glass
Author(s):Liu, Chun-Xiao(1,3); Liu, Tao(2); Liu, Xiu-Hong(2); Wei, Wei(1); Peng, Bo(1)Source: Chinese Physics Letters Volume: 28 Issue: 11 DOI: 10.1088/0256-307X/28/11/114205 Published: November 2011Abstract:We report the fabrication of planar waveguides in Nd3+-doped phosphate glass by helium ion implantation. The guiding properties of the waveguide are evaluated by a prism coupler and end-face coupling methods. The refractive index profile of the waveguide is reconstructed by using the intensity calculation method. Absorption and fluorescence investigations reveal that helium ion implantation causes only slight changes in the optical properties, suggesting the possible application of the fabricated structures as waveguide lasers. ? 2011 Chinese Physical Society and IOP Publishing Ltd.Accession Number: 20220711666091 -
Record 215 of
Title:Nonlinear characterization of silver nanocrystals incorporated tellurite glasses for fiber development
Author(s):Zhou, Zhiguang(1,3); Tan, Wenjiang(2); Si, Jinhai(2); Zhan, Huan(1,3); He, Jianli(1,3); Lin, Aoxiang(1)Source: Asia Communications and Photonics Conference and Exhibition, ACP 2011 Volume: Issue: DOI: 10.1117/12.904670 Published: November 13, 2011Abstract:To develop high nonlinear optical fibers for all-optical switching applications, 7.5 wt% AgNO3 was incorporated into tellurite glasses with composition of 75TeO2-20ZnO-5Na2CO3 (TZN75) under precisely-controlled experimental conditions to form 7.5Ag-TZN75 glass. Surface Plasmon resonance absorption peak of Ag nanocrystals embedded in 7.5Ag-TZN75 glass was found to center at 552 nm. By degenerated four-wave mixing method, the non-resonant nonlinear refractive index, n2, of 7.5Ag-TZN75 glass was measured to be 7.54×10-19 m2.W-1 at 1500 nm, about 3 times of the reference TZN75 glass without any dopant and 27 times of the silicate glasses and fibers, and the response time is about 1 picosecond. ? 2011 SPIE-OSA-IEEE.Accession Number: 20145200367429 -
Record 216 of
Title:Multiple incoherent gray photorefractive spatial solitons
Author(s):Lu, Keqing(1); Zhang, Yuhong(2,3); Tian, Ning(1); Li, Kehao(2,3); Zhang, Yiqi(2); Zhang, Xianfeng(1); Miao, Changyun(1); Zhang, Yanpeng(4); Xu, Jingjun(5)Source: Optical and Quantum Electronics Volume: 42 Issue: 5 DOI: 10.1007/s11082-011-9450-2 Published: May 2011Abstract:We show that an even-number sequence of multiple incoherent gray photorefractive spatial screening solitons is possible. When the external voltage is small, only an incoherent Y-junction photorefractive spatial screening soliton is generated, corresponding to the lowest order in the even-number incoherent soliton sequence. When the external voltage is increased, the incoherent gray soliton beam splits into an even-number sequence of multiple incoherent gray photorefractive spatial screening solitons. For a given physical system such an even-number sequence of multiple incoherent gray photorefractive spatial screening solitons is obtained by either increasing the external voltage and decreasing the full width half maximum (FWHM) of the beam's intensity or increasing the external voltage and decreasing the beam's grayness. ? 2011 Springer Science+Business Media, LLC.Accession Number: 20112514082817