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Upper mantle seismic anisotropy beneath a convergent boundary:SKS waveform modeling in central Tibet

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Science China Earth Sciences 2014年第4期57卷 759-776页

作者： zhao Liang zhao ming LU Gang State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences

This study used SKS waveforms from the International Deep Profiling of Tibet and the Himalayas(INDEPTH) III dataset and a new 2D method for modeling seismic waves in anisotropic media to construct an image of anisotropic structures beneath central Tibet.A preferred model revealed three-segment anisotropic structures in the upper mantle beneath the study *** modeling demonstrated that the anisotropy was mainly generated by the lithosphere but not the asthenosphere,and that an anisotropic model with a flatter axis of symmetry provides a more consistent interpretation of the observations than models having steeply dipping symmetry axes.A relatively low velocity zone may underlie or intermingle with the anisotropic structures in the northern portion of the *** tests also indicate that variations in the elastic constants and depth extent of the anisotropy assumed by the calculations do not affect the general conclusions,although trade-offs exist among certain model *** modeling results suggest that the complex seismic structures in central Tibet were associated with underthrusting of the Indian lithosphere beneath the Asian lithosphere;the inferred flat symmetry axis of the anisotropy was likely generated during this collision *** this were not the case,the inherited anisotropy would exhibit a steeply dipping axis of symmetry,parallel to the direction of underthrusting.

关键词： waveform modeling spectral element method upper mantle anisotropy central Tibet

Design of a(480,240)CMOS Analog Low-Density Parity-Check Decoder

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China Communications 2017年第8期14卷 41-53页

作者： Hao zheng zhe zhao Xiangming Li Hangcheng Han School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China

Digital low-density parity-check(LDPC) decoders can hardly meet the power-limits brought by the new application scenarios. The analog LDPC decoder, which is an application of the analog computation technology, is considered to have the potential to address this issue to some extent. However, due to the lack of automation tools and analog stopping criteria, the analog LDPC decoders suffer from costly handcraft design and additional decoding delay, and are not feasible to practical applications. To address these issues, a decoder architecture using reusable building blocks is designed to lower the handcraft design, and a probability stopping criterion that is specially designed for analog decoder is further planned and implemented to reduce the decoding delay. Then, a(480,240) CMOS analog LDPC decoder is designed and fabricated in a 0.35-μm CMOS technology. Experimental results show that the decoder prototype can achieve 50 Mbps throughput when the power consumption is about 86.3m W, and the decoding delay can be reduced by at most 93% compared with using the preset maximum decoding delay in existing works.

关键词： LDPC analog decoder handcraft design reduction probability stopping criterion for analog decoding reusable building block

A Robust Face Recognition Method Combining LBP with Multi-mirror Symmetry for Images with Various Face Interferences

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International Journal of Automation and computing 2019年第5期16卷 671-682页

作者： Shui-Guang Tong Yuan-Yuan Huang zhe-ming Tong State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityNo.38Zheda RoadHangzhou 310027China School of Mechanical Engineering Zhejiang UniversityNo.38Zheda RoadHangzhou 310027China

Face recognition(FR) is a practical application of pattern recognition(PR) and remains a compelling topic in the study of computer vision. However, in real-world FR systems, interferences in images, including illumination condition, occlusion, facial expression and pose variation, make the recognition task challenging. This study explored the impact of those interferences on FR performance and attempted to alleviate it by taking face symmetry into account. A novel and robust FR method was proposed by combining multi-mirror symmetry with local binary pattern(LBP), namely multi-mirror local binary pattern(MMLBP). To enhance FR performance with various interferences, the MMLBP can 1) adaptively compensate lighting under heterogeneous lighting conditions, and 2) generate extracted image features that are much closer to those under well-controlled conditions(i.e., frontal facial images without expression). Therefore, in contrast with the later variations of LBP, the symmetrical singular value decomposition representation(SSVDR) algorithm utilizing the facial symmetry and a state-of-art non-LBP method, the MMLBP method is shown to successfully handle various image interferences that are common in FR applications without preprocessing operation and a large number of training images. The proposed method was validated with four public data sets. According to our analysis, the MMLBP method was demonstrated to achieve robust performance regardless of image interferences.

关键词： Face recognition(FR) local binary pattern(LBP) facial symmetry image interferences multi-mirror average

The front-end electronics design of dose monitors for beam delivery system of Shanghai Advanced Proton Therapy Facility

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Nuclear Science and Techniques 2017年第6期28卷 154-160页

作者： Bin-Qing zhao ming-Hua zhao ming Liu Chong-Xian Yin Hang Shu Shanghai Institute of Applied Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

A front-end electronics of dose monitor has been developed for measuring irradiation dose to the patient in Shanghai Advanced Proton Therapy *** parallel plate ionization chamber is used for the dose *** the traditional method of recycling capacitor integration and voltage-to-frequency conversion,this dose monitor electronics uses the trans-impedance amplifier and analog-to-digital conversion *** performs satisfactorily,with the integral nonlinearity of less than ±0.04 nA in the range of-400 to 50 nA and the resolution of about±0.6 nA.

关键词： Front-end electronics Dose monitor Proton therapy

Area-efficient analog decoder design for low density parity check codes in deep-space applications

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The Journal of China Universities of Posts and Telecommunications 2017年第4期24卷 69-75页

作者： zhao zhe Gao Fei zheng Hao Yin Xue School of Information and Electronics Beijing Institute of Technology Beijing 100081 China

Area-efficient design methodology is proposed for the analog decoding implementations of the rate-l/2 accumulate repeat-4 jagged-accumulate （AR4JA） low density parity check （LDPC） code. The proposed approach is designed using optimized decoding architecture and regularized routing network, in such a way that the overall wiring overhead is minimized and the silicon area utilization is significantly improved. The prototyping chip used to verily the approach is tully integrated in a four-metal double-poly 0.35 lam complementary metal oxide semiconductor （CMOS） technology, and includes an input-output interface that maximizes the decoder throughput. The decoding core area is 2.02 mm2 with a post-layout area utilization of 80%. The decoder was successfully tested at the maximum data rate of 10 Mbit/s, with a core power consumption of 6.78 mW at 3.3 V, which corresponds to an energy per decoded bit of 0.677 nJ. The proposed analog LDPC decoder with low processing power and high-reliability is suitable lbr space- and power-constrained spacecraft system.

关键词： low density parity check (LDPC) code analog decoding iterative message-passing algorithms hardware efficient area utilization

Alpha radiolysis of nitric acid aqueous solution irradiated by 238Pu source

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Nuclear Science and Techniques 2017年第4期28卷 74-83页

作者： zhe Liu Zhong Fang Liang Wang Hui He ming-Zhang Lin School of Nuclear Science and Technology University of Science and Technology of China Hefei 230026 China China Institute of Atomic Energy Beijing 102413 China Institute of Nuclear Energy Safety Technology Chinese Academy of Sciences Hefei 230031 China

Alpha radiolysis of nitric acid aqueous solution by a ^(238)Pu source is investigated experimentally and *** time dependence of the nitrous acid yield on dose rate,nitric acid concentration,and nitrate ion concentration is studied.A novel kinetic model for the α-radiolysis of nitric acid aqueous solution is established,by considering the direct and indirect *** simulation results agree well with the experimental data,indicating the validity of our model to treat the reaction paths for generation and consumption of nitrous *** is shown that the redox reactions involving Pu cannot be neglected in theα-radiolysis of the *** results provide a better understanding of the α-ray radiolysis of aqueous nitric acid.

关键词： a-Radiolysis Nitric acid Plutonium Aqueous solution Kinetic model Nitrous acid

Evaluation of earthquake signal characteristics for early warning

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Earthquake Engineering and Engineering Vibration 2012年第3期11卷 435-443页

作者： Kong Qingkai zhao ming Building Engineering Department Tongji UniversityShanghai 200092China

This paper evaluates different characteristics for earthquake early warning. The scaling relationships between magnitude, epicenter distance and calculated parameters are derived from earthquake event data fi＇om USGS. The standard STA/LTA method is modified by adding two new parameters to eliminate the effects of the spike-type noise and small pulsetype noise ahead of the onset of the P-wave. After the detection of the P-wave, the algorithm extracts 12 kinds of parameters from the first 3 seconds of the P-wave. Then stepwise regression analysis of these parameters is performed to estimate the epicentral distance and magnitude. Six different parameters are selected to estimate the epicentral distance, and the median error for all 419 estimates is 16.5 krn. Four parameters are optimally combined to estimate the magnitude, and the mean error for all events is 0.0 magnitude units, with a standard deviation of 0.5. Finally, based on the estimation results, additional work is proposed to improve the accuracy of the results.

关键词： earthquake early warning epicentral distance estimation magnitude estimation

Fast,faster,and the fastest structured illumination microscopy

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Light(Science & Applications) 2024年第9期13卷 1693-1695页

作者： Tianyu zhao ming Lei MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter School of PhysicsXi’an Jiaotong UniversityXi’an 710049China

Parallel acquisition-readout structured-illumination microscopy(PAR-SIM)was designed for high-speed raw data *** utilizing an xy-scan galvo mirror set,the raw data is projected onto different areas of the camera,enabl... 详细信息

关键词： illumination faster utilizing

Theoretical studies on high energetic density nitramine explosives containing pyridine

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Science China Chemistry 2012年第9期55卷 1903-1909页

作者： zhao Guozheng LU ming School of Chemical Engineering Nanjing University of Science&TechnologyNanjing 210094China

The insensitive property of explosives containing pyfidine is combined with the high energy of nitramine explosives, and the concept of new nitramine explosives containing pyridine is proposed, into which nitramine group with N-N bonds is intro- duced as much as possible. Based on molecular structures of nitramine compounds containing pyridine, density functional the- ory （DFT） calculation method was applied to study designed molecules at B3LYP/6-31＋G（d） level. The geometric and elec- tronic structures, density, heats of formation （HOF）, detonation performance and bond dissociation energies （BDE） were investigated and comparable to 1,3,5-trinitro-l,3,5-triazinane （RDX） and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane （HMX）. The simulation results reveal that molecules B and D perform similarly to traditionally used RDX. Molecule E outperform RDX, with performance that approach that of HMX and may be considered as potential candidate of high energy density compound （HEDC）. These results provide basic information for molecular design of novel high energetic density compounds.

关键词： density functional theory (DFT) nitramine pyridine detonation properties bond dissociation energies (BDE)