2012
2012
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Record 85 of
Title:Photoemission stability of negative electron affinity GaN photocathode
Author(s):Junju, Zhang(1); Xiaohui, Wang(1); Wenzheng, Yang(2); Weidong, Tang(2); Xiaoqian, Fu(1); Biao, Li(1); Benkang, Chang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8555 Issue: DOI: 10.1117/12.2001125 Published: 2012Abstract:The stability for reflection-mode GaN photocathode has been investigated by monitoring the photocurrent and the spectral response at room temperature. We watch that the photocurrent of the cathode decays with time in the vacuum system, and compare the spectral response curves after activation and after degradation. The photocurrent decay mechanism for reflection-mode NEA GaN photocathode was studied by the surface model GaN (Mg) :Cs:O-Cs. The reduction of the effective dipole quantity, which is caused by harmful gases, is the key factor of the photocurrent reduction. ? 2012 SPIE.Accession Number: 20132916514958 -
Record 86 of
Title:Structural analysis and design optimization of a selective laser sintering system
Author(s):Shuai, Cijun(1,2); Yang, Bo(1); Nie, Yi(1); Hu, Huanlong(1); Peng, Shuping(3); Zhou, Ying(1)Source: Advanced Materials Research Volume: 421 Issue: DOI: 10.4028/www.scientific.net/AMR.421.544 Published: 2012Abstract:A three dimensional geometric model of a homemade selective laser sintering (SLS) system is simplified and imported into Ansys Finite Element Software for static and modal analysis. The analysis results show that the supporting base that holds up the laser system undergoes large deformations. The machining accuracy can hardly meet the high-precision requirements of sintered parts with complex internal and external geometries. A method is put forward for the structural optimization of the SLS system. The calculation results show that the bending deformation of the supporting base decreases by 73.2%, and the maximum stress also decreases significantly. It indicates that the high precision manufacturing can be achieved with the improved SLS system.Accession Number: 20115214641954 -
Record 87 of
Title:Near backscatter light diagnostic system on SG-III prototype laser facility
Author(s):Xu, Tao(1); Peng, Xiaoshi(1); Wei, Huiyue(1); Yan, Yadong(2); Wang, Feng(1); Liu, Shenye(1)Source: Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams Volume: 24 Issue: 12 DOI: 10.3788/HPLPB20122412.2853 Published: December 2012Abstract:Development of the near backscatter light diagnostic system is important to measuring the stimulated Brillouin and stimulated Raman scatter so that the near backscatter light fraction of the ICF drive laser will be determined. Based on SG-III prototype laser facility, a near backscatter light diagnostic system with an ellipsoidal mirror and other relay optics as core elements is designed and implemented on the facility. The whole system is well held and modulated by a portable configuration. Both the optical and mechanical design items are introduced in this paper. According to the experiment results, the system is credible and effective.Accession Number: 20125115822529 -
Record 88 of
Title:The design of high performance tracking system based on multi TMS320C6678
Author(s):Wu, Min(1,2); Su, Xiu-Qin(2)Source: 2012 5th International Congress on Image and Signal Processing, CISP 2012 Volume: Issue: DOI: 10.1109/CISP.2012.6470025 Published: 2012Abstract:A high performance TMS320C6678 DSP, which contains 8 1.25 GHZ C66 corepacs and four channels of SRIO, was developed. Then we use 4 TMS320C6678 and FPFA to design a high-performance tracking system platform, which is a completely a new-generation tracking system compared to the traditional systems for its multi-core DSP array and all kinds of high-speed series interfaces. The FPGA mainly do controlling tasks and the DSPs accomplish the complex tracking algorithm. At last we designed two other system architectures applying to different requirement for future use. ? 2012 IEEE.Accession Number: 20131216134086 -
Record 89 of
Title:Design of the autocollimator interface based on TMS320F2812
Author(s):Gao, Li-Na(1,2); Hu, Xiao-Dong(1)Source: Applied Mechanics and Materials Volume: 235 Issue: DOI: 10.4028/www.scientific.net/AMM.235.164 Published: 2012Abstract:In order to convenient the design of the autocollimator interface, this paper introduces the design of hardware and software of the autocollimator interface, and detailed analysis some key links. The SPI extension module (EEPROM) based on abundance on-chip resource of TMS320F2812 DSP is used to storage the equivalent of misalignment angle; The CAN extension module (CAN bus) based on CAN module is used to communicate with other computers; SCI extension module (RS232) is used which is convenient for the system debugging, and extension interfaces are left. Meanwhile, the corresponding design of software is also given in the paper. Prototype tests show that the design of the autocollimator interface can fully satisfy the requirements of the system. The design experience can be referred in similar engineering. ? (2012) Trans Tech Publications, Switzerland.Accession Number: 20130115849437 -
Record 90 of
Title:A new design of large area MCP-PMT for the next generation neutrino experiment
Author(s):Wang, Yifang(1); Qian, Sen(1); Zhao, T.(1); Tian, Jinshou(2); Li, Huirui(3); Cao, Jun(1); Xu, Xiangyan(2); Wang, Xiaoyun(3); Liu, Shudong(1); Liu, Hulin(2); Liu, Shulin(1); Liu, Delin(3); Heng, Yuekun(1); Cao, Xibin(3); Shentu, Jun(3)Source: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Volume: 695 Issue: DOI: 10.1016/j.nima.2011.12.085 Published: December 11, 2012Abstract:This manuscript discusses a new design of large area MCP-PMT for the next generation neutrino experiments. The main motivation of the design is to improve the quantum efficiency (photo detection efficiency) of the PMT. Two sets of small MCP units, the transmission photocathode coated on the front hemisphere and the reflection photocathode coated on the rear hemisphere are assembled in the same glass envelope to form nearly 4π viewing angle to enhance the efficiency of the photoelectron detection. The photoelectrons from the 4π photocathode are collected and amplified by two sets of MCP units. Our goal is eventually to produce 20 in. diameter PMT following such an approach. We will report preliminary results of our ptoelectronic simulation and the results of a 5 in. diameter prototype PMT. Future plans and prospects are discussed at the end. ? 2011 Elsevier B.V.Accession Number: 20124415613693 -
Record 91 of
Title:A run-length based algorithm for feature extraction from multi-target image
Author(s):Zhang, Kun(1,2); Hao, Wei(1); Xu, Zhaohui(1)Source: 2012 5th International Congress on Image and Signal Processing, CISP 2012 Volume: Issue: DOI: 10.1109/CISP.2012.6469777 Published: 2012Abstract:This paper presented a new run-length encoding based method of extracting features from multi-target image. The algorithm uses linked list structure to store data. The data are comprised of three parts, the message in run length, the equal values and the features of the image, which are in one-to-one mapping. While scanning, we only record the features of the image according to the label. After scanning the last pixel, we merge the linked list which contains the features of image according to the equal list. Compared with other approaches, the proposed one is faster and simpler, especially it can label the binary image exactly, no matter how complicated the image is. ? 2012 IEEE.Accession Number: 20131216133838 -
Record 92 of
Title:Investigation of quantum beatings at 608 cm-1 and 70 cm-1 in rb vapor
Author(s):Zhu, Chang Jun(1); He, Jun Fang(2); Zhai, Xue Jun(1); Xue, Bing(1); Zhang, Chong Hui(1)Source: Solid State Phenomena Volume: 181-182 Issue: DOI: 10.4028/www.scientific.net/SSP.181-182.413 Published: 2012Abstract:Two coupled axially phase-matched parametric four-wave mixings have been achieved in Rb vapor by using broad bandwidth laser pulses. Coherent radiations at 420 nm produced by difference-frequency optical wave mixing processes were detected and a pump-probe scheme was employed to record time varying characteristics of the parametric four-wave mixing signals. Quantum beatings at 608 cm-1 and 70 cm-1 were retrieved from the time varying signals by Fourier transform. Moreover, time dependent Fourier transform was utilized to analyze the dynamics of quantum beatings. The results indicate that two wave packets associated with the two quantum beating frequency components interact strongly and the quantum beating dynamics can be controlled by adjusting Rb number density. ? (2012) Trans Tech Publications, Switzerland.Accession Number: 20160201792887 -
Record 93 of
Title:Confidence guided enhancing brain tumor segmentation in multi-parametric MRI
Author(s):Reddy, Kishore K.(1); Solmaz, Berkan(1); Yan, Pingkun(2); Avgeropoulos, Nicholas G.(3); Rippe, David J.(4); Shah, Mubarak(1)Source: Proceedings - International Symposium on Biomedical Imaging Volume: Issue: DOI: 10.1109/ISBI.2012.6235560 Published: 2012Abstract:Enhancing brain tumor segmentation for accurate tumor volume measurement is a challenging task due to the large variation of tumor appearance and shape, which makes it difficult to incorporate prior knowledge commonly used by other medical image segmentation tasks. In this paper, a novel idea of confidence surface is proposed to guide the segmentation of enhancing brain tumor using information across multi-parametric magnetic resonance imaging (MRI). Texture information along with the typical intensity information from pre-contrast T1 weighted (T1 pre), post-contrast T1 weighted (T1 post), T2 weighted (T2), and fluid attenuated inversion recovery (FLAIR) MRI images are used to train a discriminative classifier at pixel level. The classifier is used to generate a confidence surface, which gives a likelihood of each pixel being a tumor or non-tumor. The obtained confidence surface is then incorporated into two classical methods for segmentation guidance. The proposed approach was evaluated on 19 groups of MRI images with tumor and promising results have been demonstrated. ? 2012 IEEE.Accession Number: 20123315340236 -
Record 94 of
Title:A biological inspired features based saliency map
Author(s):Han, Bing(1); Li, Xuelong(2); Gao, Xinbo(1); Tao, Dacheng(3,4)Source: 2012 International Conference on Computing, Networking and Communications, ICNC'12 Volume: Issue: DOI: 10.1109/ICCNC.2012.6167446 Published: 2012Abstract:A visual attention mechanism is believed to be responsible for the most informative spots in complex scenes. We proposed a novel biologically inspired attention model based on Cortex-like mechanisms and sparse representation. Biological Inspired model, HMAX model, is a feature extraction method and this method is motivated by a quantitative model of visual cortex. This biological inspired feature will be used to build the Saliency Criteria to measure the perspective fields. Saliency Criteria is obtained from Shannon's information entropy and sparse representation. We demonstrate that the proposed model achieves superior accuracy with the comparison to classical approach in static saliency map generation on real data of natural scenes and psychology stimuli patterns. ? 2012 IEEE.Accession Number: 20121714960595 -
Record 95 of
Title:Classifiction for hyperspectral imagery based on nonlocal weighted joint sparsity model
Author(s):Li, Jiayi(1); Zhang, Hongyan(1); Huang, Yuancheng(2); Zhang, Liangpei(1)Source: Workshop on Hyperspectral Image and Signal Processing, Evolution in Remote Sensing Volume: Issue: DOI: 10.1109/WHISPERS.2012.6874316 Published: 2012Abstract:A nonlocal weighted joint sparse representation classification method for hyperspectral image is proposed in this paper. A discriminated contributions based on nonlocal spatial structure information are utilized in the joint sparsity model framework. The proposed algorithm is tested on two hyperspectral images. Experimental results suggest that the proposed algorithm shows superior performance over other sparsity-based algorithms and the classical hyperspectral classifier SVM. ? 2012 IEEE.Accession Number: 20143518118147 -
Record 96 of
Title:Analytical and experimental demonstration of depth of field extension for incoherent imaging system with a standard sinusoidal phase mask
Author(s):Zhao, Hui(1); Li, Yingcai(1)Source: Chinese Optics Letters Volume: 10 Issue: 3 DOI: 10.3788/COL201210.031101 Published: March 2012Abstract:The wavefront coding technique is used to enlarge the depth of field (DOF) of incoherent imaging systems. The key to wavefront coding lies in the design of suitable phase masks. To date, numerous kinds of phase masks are proposed. However, further understanding is needed regarding phase mask with its phase function being in a standard sinusoidal form. Therefore, the characteristics of such a phase mask are studied in this letter. Deriving the defocused optical transfer function (OTF) analytically proves that the standard sinusoidal phase mask is effective in extending the DOF, and actual experiments confirm the numerical results. At the same time, with the Fisher information as a criterion, the standard sinusoidal phase mask shows a higher tolerance to focus errors (especially severe focus errors) than the classical cubic phase mask. ? 2012 Chinese Optics Letters.Accession Number: 20121514938105