2017
2017
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Record 181 of
Title:On Combining Social Media and Spatial Technology for POI Cognition and Image Localization
Author(s):Qian, Xueming(1); Lu, Xiaoqiang(2); Han, Junwei(3); Du, Bo(4); Li, Xuelong(2)Source: Proceedings of the IEEE Volume: 105 Issue: 10 DOI: 10.1109/JPROC.2017.2731600 Published: October 2017Abstract:With fast development of information engineering and social network, people's locations can be conveniently sensed by spatial technology, such as global positioning systems (GPS), base stations, Wi-Fi access points and even from the appearances of the photos they have taken. The social networks and the online shopping platforms have been gathering billions of users, who share a large amount of images taken in places they live in and visit. We can leverage the social networks to express our opinions about the services and places of interest (POIs). The interactions among users, and user and POIs or services generate big social media data, which have rich information for user, location, and service cognition. Many real-time network applications rely heavily on the accurate social users' locations. How to sense the locations from multisource social media data is very important and challenging. Thus, in this paper, we give a systematic review of the works that combine social media and spatial technology for POI cognition and image localization. ? 1963-2012 IEEE.Accession Number: 20173604108945 -
Record 182 of
Title:Optimization design of a 20-in. elliptical MCP-PMT
Author(s):Chen, Ping(1,2,3); Tian, Jinshou(1,3); Wei, Yonglin(1); Liu, Hulin(1); Sai, Xiaofeng(1); He, Jianping(1); Chen, Lin(1,2); Wang, Xing(1); Lu, Yu(1)Source: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Volume: 841 Issue: DOI: 10.1016/j.nima.2016.10.036 Published: January 1, 2017Abstract:This paper describes the simulation work for optimizing the newly developed 20-in. elliptical MCP-PMT by enlarging the outside diameters of the two focusing electrodes and the open area of the glass bulb. Effects of biasing voltages applied to the two focusing electrodes and the MCP input facet are studied. With the new design of the 20 in. MCP-PMT, the transit time spread of the prototype can be less than 3 ns and the collection efficiency is as much as the present prototype. ? 2016 Elsevier B.V.Accession Number: 20164502998480 -
Record 183 of
Title:Stand-off laser Raman spectroscopy and its advancement in explosives detection
Author(s):Liu, Sheng-Run(1,2); Xue, Bin(1,2); Li, Yi-Zhe(1,2); Wang, Hui(3)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10461 Issue: DOI: 10.1117/12.2285181 Published: 2017Abstract:The explosives detection has been a hot and difficult issue in the field of security?1/4it is particularly important to detect explosives quickly and reliably. There are many methods to detect explosives currently, stand-off Raman spectroscopy is one of the most promising and practical technologies, this technique can be used for non-contact and nondestructive detection, ensure the safety of attendants, at the same time the precision and speed of detection are also very high and be characterized by rapid response. This paper mainly gives an account of the fundamental principle of Raman spectroscopy, as well as recount major challenges of Standoff Laser Raman Spectroscopy applied in explosives detection and corresponding solutions. From the perspective of the system, this paper sums up related theories and techniques of the excitation laser and telescopic system etc. Ultimately, a brief analysis and summary of the development trend of this technology is given. ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Accession Number: 20180404675575 -
Record 184 of
Title:The Gain and Time Characteristics of Microchannel Plates in Various Channel Geometries
Author(s):Chen, Lin(1,2,3); Wang, Xingchao(4); Tian, Jinshou(1,5); Zhao, Tianchi(6); Liu, Chunliang(2); Liu, Hulin(1); Wei, Yonglin(1); Sai, Xiaofeng(1); Wang, Xing(1); Sun, Jianning(4); Si, Shuguang(4); Chen, Ping(1); Tian, Liping(1); Hui, Dandan(1); Guo, Lehui(1)Source: IEEE Transactions on Nuclear Science Volume: 64 Issue: 4 DOI: 10.1109/TNS.2017.2676010 Published: April 2017Abstract:Microchannel plates (MCPs) are widely used as electron, ion, and X-ray detectors. The gain factor and time resolution of the MCP are strongly dependent on its operating and geometry parameters (applied voltage, length-to-diameter ratio, bias angle, and electrode penetration depth). Measurements about this dependence are sparse and do not cover the full range of the parameters. In this paper, 3-D single channel models are developed in computer simulation technology studio suit to systematically and comprehensively calculate the MCP gain and time resolution for various operating and geometry parameters. Furman secondaries electron emission model is employed in our simulation. Simulated result of the gain versus bias voltage is validated by the available experimental data. Finally, geometry parameters of L = 373.6 μm, D =10 μm, hin = hout = 5 μm, and θ = 12 are proposed to optimize the MCP performances. Simulation results show that the gain, mean transit time, and transit time spread of the optimized MCP are expected to reach 128 012, 128 ps and 19 ps at the applied voltage of 1000 V. ? 2017 IEEE.Accession Number: 20171903638504 -
Record 185 of
Title:Real-time classification of forearm movements based on high density surface electromyography
Author(s):Wei, Yue(1,4); Geng, Yanjuan(1); Yu, Wenlong(1); Samuel, Oluwarotimi Williams(1,2); Jiang, Naifu(3); Zhou, Hui(1); Guo, Xin(4); Lu, Xiaoqiang(5); Li, Guanglin(1,2)Source: 2017 IEEE International Conference on Real-Time Computing and Robotics, RCAR 2017 Volume: 2017-July Issue: DOI: 10.1109/RCAR.2017.8311868 Published: July 2, 2017Abstract:Partial or complete loss of the upper limb motor function has great impact on the activities of daily life (ADL) of post-stroke survivors. To improve the rehabilitation effect of fine motor function of forearms, a couple of recent studies focused on methods that try to decode the limb motion intent of patients through physical exercises. However, there exist a few studies on real-time active rehabilitation method for the classification of multiple hand movements. In the current investigate, a pattern-recognition based rehabilitation environment was set up using high-density surface electromyogram (HD-sEMG) and the real-time classification performance of 21 forearm motions was investigated with eight healthy subjects. The results showed that the average motion completion rate across all subjects was 91.17% + 2.86%, which suggests the potential of intention-initiated approach in assistive rehabilitation technique. ? 2017 IEEE.Accession Number: 20183105627013 -
Record 186 of
Title:Optimization Design and Test for the Front Frame of a Large Off-axis TMA Space Camera
Author(s):Wei, Lei(1,2); Zhang, Lei(1,3); Xie, Peng(1); Chen, Su(4)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 46 Issue: 5 DOI: 10.3788/gzxb20174605.0522001 Published: May 1, 2017Abstract:To guarantee the high stability and high precision of an off-axis thee-mirror optical system space camera, a integration front frame structure was designed to support the second mirror and folded mirror according to the characteristics of the same height of second mirror and folded mirror in optical axis direction, and a topology optimization method based on constraint mode and free mode was proposed to optimize the front frame structure. Then, the integrated structure was assembled into the entire camera after optimization, and the finite element analysis of static was carried out. The results show that the camera maintains excellent static performance with the optical tilt between the primary mirror and secondary mirror being less than 9″ and the optical tilt between the primary mirror and fold mirror being less than 22.4″, the optical eccentricity between the primary mirror and secondary mirror being less than 0.021 mm, meeting the tolerance requirement of system. By free modal analysis and test to the integrated front frame structure, the results verify the correctness of the design method. The proposed topology optimization method can efficient avoid the defect of topology optimization based on constraint modal frequency that there is no relationship between the constraint points. It can provide reference for design the space camera with high-resolution and wide field. ? 2017, Science Press. All right reserved.Accession Number: 20173104014252 -
Record 187 of
Title:Status of the 20 inch MCP-PMT prototype development for JUNO experiment
Author(s):Gao, Feng(1,2,3); Huang, Guorui(4); Heng, Yuekun(1,2); Li, Dong(4); Liu, Hulin(5); Liu, Shulin(1,2); Li, Weihua(5); Ning, Zhe(1,2); Qi, Ming(6); Qian, Sen(1,2); Ren, Ling(4); Sun, Jianning(4); Si, Shuguang(4); Tian, Jinshou(5); Wang, Yifang(1,2); Wei, Yonglin(5); Xin, Liwei(5); Zhao, Tianchi(1)Source: Journal of Physics: Conference Series Volume: 888 Issue: 1 DOI: 10.1088/1742-6596/888/1/012050 Published: September 20, 2017Abstract:A new concept of large area photomultiplier based on MCPs was conceived for JUNO by the scientists in IHEP, Beijing. In the past 5 years by collaborative work of the MCP-PMT collaboration in China, 8 inch and 20 inch prototypes were produced. Test results show that this type of MCP-PMT can have similar photon counting performance as the traditional dynode type PMTs. With the better collection efficiency, low after pulse rate, low Low-Potassium Glass, the JUNO ordered 75% about 15,000 20 inch MCP-PMT from NNVT at the end of 2015. This manuscript just give the overview this type of MCP-PMT, the R&D process and the main characteristics. ? Published under licence by IOP Publishing Ltd.Accession Number: 20174404342933 -
Record 188 of
Title:Electrostatic field assisted micro imprint lithography technology
Author(s):Liu, Min-Zhe(1,2); Wang, Tai-Sheng(1); Li, He-Fu(1); Liu, Zhen-Yu(1); Chen, Zuo-Long(3); Yu, Wei-Xing(4)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 25 Issue: 3 DOI: 10.3788/OPE.20172503.0663 Published: March 1, 2017Abstract:In this paper, a new type of micro imprint lithography assisted by electrostatic field was introduced, and an in-depth theoretical research was conducted on its technological process. First, numerical simulation software (COMSOLTM Multiphysics) was adopted to establish a transient simulation model for electrostatic filed assisted imprint lithography and discussed the evolution process of micro structure in different time domains. Then a detailed analysis was conducted on the qualitative relationship between the micro structure formation and simulation experiment parameters, during which it was found that properly reducing the polar plate spacing, template bulging period and increasing the bulging height, initial polymer film thickness and voltage were beneficial to formation of the micro-nano structure. Finally, a spherical cap micro structure with 31 μm hollow structure was obtained through optimization of the simulation experiment parameters. Compared with traditional imprint method, the electrostatic field assisted micro imprint, which is characterized by simple process and lower cost, can be widely applied to the micro electronic and mechanical system, photonics, genetics and tissue system etc. ? 2017, Science Press. All right reserved.Accession Number: 20172203711460 -
Record 189 of
Title:Embedded nanogratings in bulk fused silica under non-diffractive Bessel ultrafast laser irradiation
Author(s):Cheng, G.(1,2); Rudenko, A.(1); D'Amico, C.(1); Itina, T.E.(1); Colombier, J.P.(1); Stoian, R.(1)Source: Applied Physics Letters Volume: 110 Issue: 26 DOI: 10.1063/1.4987139 Published: June 26, 2017Abstract:We report the formation of embedded nanogratings in bulk fused silica under quasi-stationary field patterns generated by ultrashort laser pulses in nondiffractive modes. The zero-order Bessel beam consists of almost non-propagative light pulses distributed along a narrow micron-sized channel sustained over a large non-diffracting length. Upon multipulse irradiation, a regular pattern of nanoplanes is formed across the channel, spaced at approximately λ/2n. Applying an electromagnetic scattering model [A. Rudenko et al., Phys. Rev. B 93, 075427 (2016)], we associate the formation of nanogratings with multiple scattering from randomly distributed scattering centers created by laser light. Constructive interference between the scattered wavelets leads to periodic excitation enhancement without requiring explicit synchronism conditions. Permanent material modifications are found whenever the local carrier densities are maximized towards the critical value. Multiple periodicities are predicted, either implicitly related to the coherent electromagnetic interaction or due to periodic field depletion and photon replenishment. ? 2017 Author(s).Accession Number: 20172703874441 -
Record 190 of
Title:High-rate and low-jitter optical pulse generation based on an optoelectronic oscillator using a cascaded polarization modulator and phase modulator
Author(s):Liu, Anni(1); Liu, Jingliang(1); Dai, Jian(1,2); Dai, Yitang(1); Yin, Feifei(1); Li, Jianqiang(1); Zhou, Yue(1); Xu, Kun(1,3)Source: ICOCN 2017 - 16th International Conference on Optical Communications and Networks Volume: 2017-January Issue: DOI: 10.1109/ICOCN.2017.8121562 Published: November 27, 2017Abstract:A novel optical pulse generator with high-rate and lowjitter is proposed based on the optoelectronic oscillator using a cascaded polarization modulator and phase modulator. Optical pulses with 10 GHz repetition rate and 29 ps width are demonstrated. According to the single-sideband phase noise of the generated microwave signal, 169 fs time jitter of the generated pulses in the 100 Hz to 1 MHz frequency range can be calculated. ? 2017 IEEE.Accession Number: 20181104902420 -
Record 191 of
Title:Online and Efficient Fabrication of Helical Long-Period Fiber Gratings
Author(s):Ren, Kaili(1,2); Ren, Liyong(1); Liang, Jian(1); Kong, Xudong(1); Ju, Haijuan(1); Wu, Zhaoxin(2)Source: IEEE Photonics Technology Letters Volume: 29 Issue: 14 DOI: 10.1109/LPT.2017.2711608 Published: July 15, 2017Abstract:By taking the advantage of inherent core-cladding eccentricities in standard single-mode fibers, in this letter, we propose and demonstrate an efficient method to fabricate helical long-period fiber gratings (H-LPFGs) by directly twisting fibers. In the fabrication process, we use a double-beam CO2 laser for heating the fiber stably and uniformly, together with an online scheme for monitoring the spectrum. Compared with other fabrication methods reported, the quality of H-LPFGs we fabricated is improved significantly, showing a high extinction ratio of over 30 dB and a low insertion loss of 1 dB. Based on the fact that H-LPFGs with different pitches for specific mode couplings can be fabricated efficiently and controllably, to the best of our knowledge, we actually achieve H-LPFGs with the highest quality up to now, which may find important applications, such as filtering, sensing, and optical vortex generation. ? 2017 IEEE.Accession Number: 20173504101986 -
Record 192 of
Title:3D thermal analysis of end-pumped Nd3+-doped index-crossover gain guided-index antiguided fiber laser
Author(s):Zhang, Weitao(1); Shen, Xiao(1,2); Liu, Jiaxi(1); Wei, Wei(1)Source: Laser Physics Volume: 27 Issue: 6 DOI: 10.1088/1555-6611/aa6991 Published: June 2017Abstract:Improved rate equations are established for the new model of index-crossover gain guided-index antiguided (IGG-IAG) fiber, then the pump and signal light power distribution along the IGG-IAG fiber are investigated. Based on the thermal conduction equations, the 3D temperature distributions of a one-end-pumped and dual-end-pumped Nd3+-doped IGG-IAG fiber laser are further analyzed. The simulation results show that many factors have an important influence on fiber temperature. The temperature of the fiber with the dual-end-pump method is obviously lower than that with the one-end-pump method, and the temperature distribution is more uniform. The larger the R value, the lower the fiber temperature, and the smaller the -Δn, the lower the fiber temperature. Thus proper fiber parameters and pump scheme may help to reduce the fiber temperature. ? 2017 Astro Ltd.Accession Number: 20172103691501