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Record 313 of
Title:Preparation and optical properties of TeO2–BaO–ZnO–ZnF2 fluoro-tellurite glass for mid-infrared fiber Raman laser applications
Author(s):Li, Jie(1); Xiao, Xusheng(2); Gu, Shaoxuan(1); Xu, Yantao(2); Zhou, Zhiguang(2); Guo, Haitao(2)
Source: Optical Materials Volume: 66 Issue: DOI: 10.1016/j.optmat.2017.03.006 Published: April 1, 2017
Abstract:A serial of novel fluoro-tellurite glasses with compositions of 60TeO2–20BaO–(20-x)ZnO–xZnF2 (x?=?0, 2, 4, 5 and 6?mol%) were prepared. The compositional dependences of glass structural evaluation, Raman gain coefficient, UV–Vis transmission spectrum, IR transmission spectrum, linear refractive index and third-order nonlinearity were analyzed. The results showed that the addition of 6?mol% ZnF2 can further improve the Raman gain coefficient to as well as 52?×?10?11?cm/W and effectively decrease around 73% and 57% absorption coefficients respectively caused by free O[sbnd]H groups (@3.3?μm) and hydrogen-bonded O[sbnd]H groups (@4.5?μm) in glass. Addition of ZnF2 does not change the UV–Vis absorption edge, optical band gap energy and infrared region cut-off edge almost, while the linear refraction index and ultrafast third-nonlinearity show unmonotonic changes. These novel fluoro-tellurite glasses may be suitable candidates for using in mid-infrared Raman fiber laser and/or amplifier. ? 2017 Elsevier B.V.
Accession Number: 20171103443058
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Record 314 of
Title:Medium and High Voltage IGBT Module Using Nanosilver Paste Sintering Technology and Its Performance Characterization
Author(s):Mei, Yunhui(1,2); Feng, Jingjing(1); Wang, Xiaomin(1); Lu, Guoquan(1); Zhang, Peng(3); Lin, Zhongkang(3)
Source: Gaodianya Jishu/High Voltage Engineering Volume: 43 Issue: 10 DOI: 10.13336/j.1003-6520.hve.20170925021 Published: October 31, 2017
Abstract:Interface contact through pressure is the way for press-pack insulated gate bipolar transistor (IGBT) modules in smart grid to conduct heat dissipation. However, the junction temperature of the press-pack IGBT modules could be too high, leading to degradation of electrical properties and even impairing the reliability, because of poor interfacial contact and poor heat dissipation. To overcome the above problems, we developed a sinter-pack IGBT module using nanosilver paste by forming electrical contact with chip to replace pressure contact in press-pack module. Then, the sinter-pack module was characterized by die-shear strength, thermal resistance, and static characteristics to compare with press-pack IGBT module. According to the experimental results, the thermal resistance of sinter-pack IGBT module decreased by 15.8%. The static electricity test results are consistent with two types of modules, further proving the feasibility of sinter-pack IGBT modules. The shear strength is around 20 MPa, indicating a good bonding quality of large area of die (13.5 mm×13.5 mm) with nanosiver paste. It is concluded that nano silver paste employed in press-pack IGBT modules can not only significantly decrease the thermal resistance of press-pack IGBT modules, but also get an excellent static electricity. Thus, a sinter-pack module is expected to be operated in smart grid because of the higher conversion efficiency, power density, and reliability during operating at high voltage and current applications. ? 2017, High Voltage Engineering Editorial Department of CEPRI. All right reserved.
Accession Number: 20175104547948
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Record 315 of
Title:1.5-MHz repetition rate passively Q-switched Nd:YVO4 laser based on WS2 saturable absorber
Author(s):Wang, Xi(1,2); Li, Lu(1,2); Li, Jin-Ping(3); Wang, Yong-Gang(1,3)
Source: Chinese Physics B Volume: 26 Issue: 4 DOI: 10.1088/1674-1056/26/4/044203 Published: April 2017
Abstract:A transmission-type tungsten disulfide (WS2)-based saturable absorber (SA) is fabricated and applied to passively Q-switched Nd:YVO4 laser. The WS2 nanosheets are deposited on a quartz substrate by the vertical evaporation method. By inserting the WS2 SA into the plano-concave laser cavity, we achieve 153-ns pulses with an average output power of 1.19Wat 1064 nm. To the best of our knowledge, both of them are the best results among those obtained by the Q-switched solid-state lasers with WS2-based absorbers. The repetition rate ranges from 1.176 MHz to 1.578 MHz. As far as we know, it is the first time that MHz level Q-switched pulses have been generated in all solid state lasers based on low-dimensional materials so far. ? 2017 Chinese Physical Society and IOP Publishing Ltd.
Accession Number: 20171903655160
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Record 316 of
Title:Watt-level high-power passively Q-switched laser based on a black phosphorus solution saturable absorber
Author(s):Wang, Xi(1,2); Wang, Zhenfu(1); Wang, Yonggang(1,3); Li, Lu(1,2); Yang, Guowen(1); Li, Jinping(3)
Source: Chinese Optics Letters Volume: 15 Issue: 1 DOI: 10.3788/COL201715.011402 Published: January 10, 2017
Abstract:A novel black phosphorus (BP) solution saturable absorber (SA) is fabricated by the liquid-phase-exfoliated method and successfully used for passively Q-switched (QS) Nd:YVO4 laser. Compared with a traditional solid SA, a BP solution SA possesses more excellent optical transparency and higher damage resistance. The shortest pulse duration and highest average output power are measured to be 119 ns and 1.23 W, respectively. To the best of our knowledge, both of them are the best results among QS solid-state lasers with BP-based absorbers so far. The repetition rate is in the range of 533.2 to 722 kHz. The results indicate the potential application of the BP solution SA into high-power solid-state pulse lasers. ? 2017 Chinese Optics Letters.
Accession Number: 20170603331857
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Record 317 of
Title:Learning multilayer channel features for pedestrian detection
Author(s):Cao, Jiale(1); Pang, Yanwei(1); Li, Xuelong(2)
Source: IEEE Transactions on Image Processing Volume: 26 Issue: 7 DOI: 10.1109/TIP.2017.2694224 Published: July 2017
Abstract:Pedestrian detection based on the combination of convolutional neural network (CNN) and traditional handcrafted features (i.e., HOG+LUV) has achieved great success. In general, HOG+LUV are used to generate the candidate proposals and then CNN classifies these proposals. Despite its success, there is still room for improvement. For example, CNN classifies these proposals by the fully connected layer features, while proposal scores and the features in the inner-layers of CNN are ignored. In this paper, we propose a unifying framework called multilayer channel features (MCF) to overcome the drawback. It first integrates HOG+LUV with each layer of CNN into a multi-layer image channels. Based on the multi-layer image channels, a multistage cascade AdaBoost is then learned. The weak classifiers in each stage of the multi-stage cascade are learned from the image channels of corresponding layer. Experiments on Caltech data set, INRIA data set, ETH data set, TUD-Brussels data set, and KITTI data set are conducted. With more abundant features, an MCF achieves the state of the art on Caltech pedestrian data set (i.e., 10.40% miss rate). Using new and accurate annotations, an MCF achieves 7.98% miss rate. As many non-pedestrian detection windows can be quickly rejected by the first few stages, it accelerates detection speed by 1.43 times. By eliminating the highly overlapped detection windows with lower scores after the first stage, it is 4.07 times faster than negligible performance loss. ? 2016 IEEE.
Accession Number: 20172703887483
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Record 318 of
Title:Graphene oxide-COOH as a new saturable absorber for both Q-switching and mode-locking fiber lasers
Author(s):Zhao, Fengyan(1,2); Wang, Yishan(1); Wang, Yonggang(3); Wang, Hushan(1,2); Cai, Yajun(1,2)
Source: Chinese Optics Letters Volume: 15 Issue: 10 DOI: 10.3788/COL201715.101402 Published: October 10, 2017
Abstract:Graphene oxide carboxylic acid (COOH), a novel two-dimensional (2D) layered material with its unique optical and electronic properties, is discovered to exhibit the saturation of optical absorption under laser illumination. Applying the liquid-phase exfoliation method, we prepare graphene oxide-COOH dispersions with deionized water and fabricate graphene oxide-COOH polyvinyl alcohol polymer composite film. We further obtain stable Q-switching pulse and mode-locked laser operation with a 22.7 MHz repetition rate and a 1.5 ps pulse duration by incorporating the graphene oxide-COOH-based saturable absorbers into the all-fiber erbium-doped fiber laser cavity. The experimental results show that the proposed graphene oxide-COOH material can act as an effective absorber for pulsed fiber lasers, which demonstrate potential applications in the area of ultrafast optics. ? 2017 Chinese Optics Letters.
Accession Number: 20174904498761
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Record 319 of
Title:JM-Net and cluster-SVM for aerial scene classification
Author(s):Lu, Xiaoqiang(1); Yuan, Yuan(1); Fang, Jie(1,2)
Source: IJCAI International Joint Conference on Artificial Intelligence Volume: 0 Issue: DOI: 10.24963/ijcai.2017/332 Published: 2017
Abstract:Aerial scene classification, which is a fundamental problem for remote sensing imagery, can automatically label an aerial image with a specific semantic category. Although deep learning has achieved competitive performance for aerial scene classification, training the conventional neural networks with aerial datasets will easily stick in overfitting. Because the aerial datasets only contain a few hundreds or thousands images, meanwhile the conventional networks usually contain millions of parameters to be trained. To address the problem, a novel convolutional neural network named Justify Mentioned Net (JM-Net) is proposed in this paper, which has different size of convolution kernels in same layer and ignores the fully convolution layer, so it has fewer parameters and can be trained well on aerial datasets. Additionally, Cluster-SVM, a strategy to improve the accuracy and speed up the classification is used in the specific task. Finally, our method surpass the state-of-art result on the challenging AID dataset while cost shorter time and used smaller storage space.
Accession Number: 20174304308520
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Record 320 of
Title:Passively Q-switched Nd: YVO4 laser based on Fe3O4 nanoparticles saturable absorber
Author(s):Wang, Xi(1,2); Wang, Yonggang(1,3); Mao, Dong(4); Li, Lu(5); Chen, Zhendong(3)
Source: Optical Materials Express Volume: 7 Issue: 8 DOI: 10.1364/OME.7.002913 Published: 2017
Abstract:We report on a passively Q-switched Nd:YVO4 laser at 1064.34 nm by using the ferroferric-oxide (Fe3O4) nanoparticles (FONPs) saturable absorber (SA). It is corroborated that the FONPs SA exhibits a large nonlinear saturable absorption property with the modulation depth of 2.49% at the laser wavelength of 1 μm. By inserting the novel SA into a V-type Nd:YVO4 laser cavity, we obtain the shortest pulse duration of 53 ns with a repetition rate of 576.4 kHz. The corresponding average output power, single pulse energy, and peak power are 104 mW, 0.18 μJ, and 3.53 W, respectively. To the best of our knowledge, it is the first time to experimentally confirm the application of FONPs in a pulsed Nd:YVO4 solid state laser. The parameters of the pulse width, average output power, and peak power are superior to those in the reported pulsed fiber lasers with FONPs SA so far. ? 2017 Optical Society of America.
Accession Number: 20173003985445
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Record 321 of
Title:Repetition Rate Multiplication Pulsed Laser Source Based on a Microring Resonator
Author(s):Wang, Weiqiang(1,2); Zhang, Wenfu(1,2); Chu, Sai T.(3); Little, Brent E.(1,2); Yang, Qinghua(4); Wang, Leiran(1,2); Hu, Xiaohong(1); Wang, Lei(1); Wang, Guoxi(1,2); Wang, Yishan(1); Zhao, Wei(1,2)
Source: ACS Photonics Volume: 4 Issue: 7 DOI: 10.1021/acsphotonics.7b00129 Published: July 19, 2017
Abstract:We demonstrate a stable high-Q microring resonator (MRR)-based pulsed laser source with adjustable repetition rate from 49 to 735 GHz, corresponds to repetition rate multiplication of up to 15× the free spectral range (FSR) of the MRR. The repetition rate multiplication is realized by temporal multiplexing multiple pulses in the MRR through simply tuning of the fiber cavity length. Thus, the repetition rate of the pulsed laser source breaks the frequency limitation of the previous dissipative four wave mixing based mode locked lasers whose repetition rate is equal to the FSR of the built in comb filter. This high quality chip-based repetition rate multiplicable pulsed laser source is an effective approach to on-chip ultrahigh speed optical clock frequency multiplication systems. ? 2017 American Chemical Society.
Accession Number: 20173003968825
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Record 322 of
Title:Graph PCA Hashing for Similarity Search
Author(s):Zhu, Xiaofeng(1); Li, Xuelong(2); Zhang, Shichao(1); Xu, Zongben(3); Yu, Litao(4); Wang, Can(5)
Source: IEEE Transactions on Multimedia Volume: 19 Issue: 9 DOI: 10.1109/TMM.2017.2703636 Published: September 2017
Abstract:This paper proposes a new hashing framework to conduct similarity search via the following steps: first, employing linear clustering methods to obtain a set of representative data points and a set of landmarks of the big dataset; second, using the landmarks to generate a probability representation for each data point. The proposed probability representation method is further proved to preserve the neighborhood of each data point. Third, PCA is integrated with manifold learning to lean the hash functions using the probability representations of all representative data points. As a consequence, the proposed hashing method achieves efficient similarity search (with linear time complexity) and effective hashing performance and high generalization ability (simultaneously preserving two kinds of complementary similarity structures, i.e., local structures via manifold learning and global structures via PCA). Experimental results on four public datasets clearly demonstrate the advantages of our proposed method in terms of similarity search, compared to the state-of-the-art hashing methods. ? 2017 IEEE.
Accession Number: 20173804181504
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Record 323 of
Title:On-chip router elements based on silicon hybrid plasmonic waveguide
Author(s):Ge, Zhiqiang(1,2,3,4); Zhang, Lingxuan(1,3,4); Wang, Guoxi(1,3,4); Zhang, Wenfu(1,3,4); Liu, Mulong(1,3,4); Li, Siqi(1,3,4); Wang, Leiran(1,3,4); Sun, Qibing(1,4); Ren, Wenzhen(1,4); Si, Jinhai(2); Zhao, Wei(1,3,4)
Source: IEEE Photonics Technology Letters Volume: 29 Issue: 12 DOI: 10.1109/LPT.2017.2695081 Published: June 15, 2017
Abstract:We have proposed and investigated micro-ring add-drop switch and M-Z interferometric element for on-chip router applications based on silicon hybrid plasmonic waveguide. The proposed silicon hybrid plasmonic waveguide possesses lower propagation loss compared with conventional plasmonic metal-insulator-metal waveguide. By employing this low loss waveguide, it is found that the proposed ring add-drop switch possesses high transmission efficiency (-1 dB), and the extinction ratio can be as high as 30 dB at 1.556 μm. In addition, the transmission efficiency of drop port for the M-Z interferometric element can be -1.15 dB at 1.55 μm. The designed elements are essential for the on-chip router in optical interconnect. ? 2017 IEEE.
Accession Number: 20172703878474
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Record 324 of
Title:Axial plane optical microscopy for particle manipulation with Weber accelerating beams
Author(s):An, Sha(1,2); Peng, Tong(1,2); Han, Guoxia(1); Huang, Zhangxiang(1); Wang, Meirong(3); Yao, Baoli(1); Zhang, Peng(1)
Source: Optics InfoBase Conference Papers Volume: Part F66-FiO 2017 Issue: DOI: 10.1364/FIO.2017.JTu3A.4 Published: 2017
Abstract:We directly observe the optical particle manipulation with Weber accelerating beams by the axial plane optical microscopy (APOM). Optically trapped particles moving along parabolic trajectories are successfully monitored by the APOM. ? OSA 2017.
Accession Number: 20174804480375
