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Comparison of long-term total ozone observations from space-and ground-based methods at Zhongshan Station,Antarctica

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Science China Earth Sciences 2017年第11期60卷 2013-2024页

作者： ZHANG lei zheng XiangDong BIAN LinGen Chinese Academy of Meteorological Sciences Beijing 100081China School of Atmospheric Physics Nanjing University of Information Science and TechnologyNanjing 210044China College of Meteorological Observation Chengdu University of lnformation and TechnologyChengdu 610225China

Total ozone errors for satellite observations at Zhongshan Station in Antarctica are characterized using their relative difference （RD） from ground-based Brewer observations during 1993-2015. All satellite total ozone observations slightly overestimated ground-based ones （with RD less than 4%）. This is in contrast to conclusions drawn from global-scale validation studies, where main ground-based reference stations are located in middle latitudes. Given multiple total ozone data per day at Zhongshan Station, observed by a sun synchronous orbit satellite, measurements at the lowest solar zenith angle （SZA） show greatest consistency with Brewer ones, having an overall RD of-0.02-1.15%. Algorithm-retrieved total ozone data from the Total Ozone Mapping Spectrometer （TOMS）, including Solar Backscatter Ultra Violet （SBUV）, TOMS-Earth Probe （EP）, Ozone Monitoring Instrument （OMI）-TOMS, show best agreement with ground-based values; followed by the Global Ozone Measurement Experiment-type Direct Fitting （GOD-FIT） algorithm for the GOME-2A, and finally the Differential Optical Absorption Spectroscopy （DOAS） --Algorithm retrieved products for satellites-detectors of Global Ozone Measurement Experiment （GOME）, Scanning Imaging Absorption spectroMetr for Atmospheric CHartographY （SCIAMACHY）, and OMI. Satellite total ozone RD presents some statistical characteristics, but no specific trends. DOAS and GOME-2A algorithms have values that significantly increase, when the SZA is above 60°-70°, whereas values for GOME-2A decrease, when the SZA is 80-85°. Satellite total ozone RD is a minimum, when the Brewer total ozone is 300-350 DU, with an obvious increase in RD values for DOAS- and GOME-2A, when the Brewer total ozone is 150-300 DU. Satellite total ozone RD obviously increases, as the time difference between satellite overpasses and Brewer measurements grows. Specifically, RD rises as the absolute time difference increases to more than 4 h, yielding an OMI-TOMS RD of more than 10%

关键词： Relative difference (RD) Satellite total ozone Brewer total ozone Zhongshan Station Antarctica

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Safety analysis of wheel brake system based on STAMP/STPA and Monte Carlo simulation

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Journal of Systems Engineering and Electronics 2018年第6期29卷 1327-1339页

作者： HU Jianbo zheng lei XU Shukui Equipment Management and Unmanned Aerial Vehicle Engineering College Air Force Engineering UniversityXi’an 710051China The 28th Research Institute of China Electronic Technology Group Corporation Nanjing 210000China

The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with traditional probability techniques based on the linear chain of events. However, it could not comprehensively analyze system safety problems, especially in operating environment, interaction of subsystems, and human factors. Thus,we consider system safety as a control problem based on the system-theoretic accident model, the processes(STAMP) model and the system theoretic process analysis(STPA) technique to compensate the deficiency of traditional techniques. Meanwhile,system safety simulation is considered as system control simulation, and Monte Carlo methods are used which consider the range of uncertain parameters and operation deviation to quantitatively study system safety influence factors in control simulation. Firstly,we construct the STAMP model and STPA feedback control loop of the wheel brake system based on the system functional requirement. Then four unsafe control actions are identified, and causes of them are analyzed. Finally, we construct the Monte Carlo simulation model to analyze different scenarios under disturbance. The results provide a basis for choosing corresponding process model variables in constructing the context table and show that appropriate brake strategies could prevent hazards in aircraft landing taxiing.

关键词： safety analysis landing taxiing system-theoretic accident model and processes(STAMP) model and system theoretic process analysis(STPA)(STAMP/STPA) feedback control loop Monte Carlo simulation

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Needle Steering for Robot-Assisted Insertion into Soft Tissue:A Survey

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 629-638页

作者： GAO Dedong lei Yong zheng Haojun State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Hangzhou 310027 China School of Mechanical Engineering Qinghai University Xining 810016 China Department of Precision Instruments and Mechanology Tsinghua University Beo'ing 100084 China

Needle insertion is a common surgical procedure used in diagnosis and *** needle steering technologies make continuous developments in theoretical and practical aspects along with the in-depth research on needle *** is necessary to summarize and analyze the existing results to promote the future development of theories and applications of needle ***,a survey of the state of the art of research is presented on algorithms of needle steering techniques,the surgical robots and *** on the analysis of the needle insertion procedure,the concept of needle steering is defined as a kinematics problem,which is to place the needle at the target and avoid the *** needle steering techniques,including the artificial potential field method and the nonholonomic model,are introduced to control the needles for improving the *** on the quasi-static thinking,the virtual spring model and the cantilever-beam model are developed to calculate the amount of needle deflection and generate the needle *** phantoms instead of the real tissue are used to verify the models mentioned in most of the *** the desired needle trajectories,the image-guided robotic devices and some novel needles are presented to achieve the needle ***,the challenges are provided involving the controllability of the long flexible needle and the properties of soft *** results and investigations can be used for further study on the precision and accuracy of needle insertion.

关键词： needle insertion needle steering robot-assisted needle insertion path planning needle deflection tissue deformation

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Easily fabricated and recyclable Pd&Cu@Al catalyst for gram-scale phosphine-free Heck reactions with high TON

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Science Bulletin 2017年第19期62卷 1325-1330页

作者： Dongliang Zhang zheng Wei lei Yu Institute of Pesticide School of Horticulture and Plant ProtectionYangzhou University School of Chemistry and Chemical Engineering Yangzhou University

A unique Pd＆Cu@Al catalyst was easily fabricated just by immersing commercial aluminum foil in a mixed xylene solution of PdC12 and CuCl2. The catalyst fabrication process led to aluminum oxide coatings in situ, which supported the metal nanoparticles and enhanced their catalytic activities for the phosphine-free Heck reaction of awl halides and styrenes with high turnover number （TON） up to 3.9×10^5. The reaction can be scaled up to at least 100 mmol and has been applied in modification of drug Lapatinib＇s intermediate with low metal residue. This novel catalyst is of good application potential in industrial production because it was extremely easy to be recycled, in regardless of the generation of the insoluble impurities or tars during the reaction processes.

关键词： Catalyst recoveryPalladiumnanoparticlesAluminum oxidePhosphine-freeSustainable chemistryHeck reaction

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Effects of phase change material(PCM)-based nanocomposite additives on thermal decomposition and burning characteristic of high energy propellants containing RDX

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Defence Technology（防务技术） 2022年第4期18卷 557-566页

作者： En-fa Fu Na Sun zheng-gang Xiao Key Laboratory of Special Energy Materials Ministry of Education School of Chemical Engineering Nanjing University of Science and Technology

A kind of phase change material(PCM)-based nanocomposite was prepared and added into high energy propellants containing RDX as additives to investigate its effect on thermal decomposition and burning characteristic of high energy *** effect of PCM-based nanocomposites on thermal decomposition of high energy propellants is investigated by TG/DSC-FTIR-MS *** to the delayed protection effect(PCM-based nanocomposites can absorb lots of heat at the range of certain temperature when it undergoes structure change or phase transitions)of PCM-based nanocomposites under the thermal decomposition condition,the thermal stability of high energy propellants modified with PCMbased nanocomposites is *** the same time,the concentration of N2,NO2,H2O and CO_(2)is increased during thermal decomposition of high energy propellants whereas NO and CO is *** burning gaseous products and burning characteristic of high energy propellants are studied by the combination of closed bomb test and Fourier transform infrared *** main burning gaseous products are N2,CO_(2),CO,H2O,CH4,*** the high energy propellant modified with PCM-based nanocomposites,the concentration of CH4is increased while CO,CO_(2) and H2O is decreased under the high-pressure burning *** progressivity factor of high energy propellants is increased by22.2%compared with the control sample while the maximum pressure is merely decreased 1.25%after the addition of the PCM-based nanocomposite,thus PCM-based nanocomposites can be used to adjust the burning process and improve the burning progressivity of high energy *** study is expected to boost the practical application of PCM-based nanocomposite to the propellant formulation and effectively control the burning characteristic of high energy propellants.

关键词： Phase change material Propellants Nanocomposite Thermal decomposition Burning

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Energy leakage in OFDM sparse channel estimation:The drawback of OMP and the application of image deblurring

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Digital Communications and Networks 2024年第5期10卷 1280-1288页

作者： gang Qiao Xizhu Qiang lei Wan Hanbo Jia Acoustic Science and Technology Laboratory Harbin Engineering University Key Laboratory of Marine Information Acquisition and Security (Harbin Engineering University) Ministry of Industry and Information Technology College of Underwater Acoustic Engineering Harbin Engineering University School of Informatics Xiamen University Key Laboratory of Underwater Acoustic Communication and Marine Information Technology (Xiamen University) Ministry of Education

In this paper,in order to reduce the energy leakage caused by the discretized representation in sparse channel estimation for Orthogonal Frequency Division Multiplexing(OFDM) systems,we systematically have analyzed the optimal locations of atoms with discrete delays for each path reconstruction from the perspective of linear fitting ***,we have investigated the adverse effects of the non-ideal inner product function on the iteration in one of the most widely used channel estimation method,Orthogonal Matching Pursuit(OMP).The study shows that the distance between the selected atoms for each path in OMP can be larger than the sampling interval,which prevents OMP-based methods from achieving better *** overcome this drawback,the image deblurring-based channel estimation method,in which the channel estimation problem is analogized to one-dimensional image deblurring,was proposed to improve the large compensation distance of traditional *** advantage of the proposed method was validated by the results of numerical simulation and sea trial data decoding.

关键词： Sparse channel estimation Orthogonal matching pursuit (OMP) Orthogonal frequency division multiplexing (OFDM) Linear fitting Image deblurring

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COMPARISONS OF LOW CARBON POLICIES IN SUPPLY CHAIN COORDINATION

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Journal of Systems Science and Systems Engineering 2014年第3期23卷 343-362页

作者： lei YANG Chenshi zheng Minghui XU School of Economics and Commerce South China University of Technology School of Economics and Management Wuhan University

This paper investigates the influence of low-carbon policies on channel coordination for a two-echelon supply chain consisting of one supplier and one retailer. Four different models are considered： the basic model, the carbon emission model, the carbon emission trading model and the carbon tax model. We find that the government policy on all carbon emission models is not universal among the firms as well as the customers. The carbon emission trading policy is always better than the carbon emission policy and the carbon tax policy when the allocated carbon emission quotas are greater than the carbon emissions. The carbon emission trading policy is proved to be an effective mechanism which can motivate the supply chain to reduce carbon emissions. Under certain conditions, the supply chain prefers the carbon emission trading policy with higher carbon price to other policies. In the framework of Stackelberg game with the supplier as the leader, for each carbon policy, the paper presents coordination mechanism with the all-unit wholesale quantity discount contract （AWQD）. We analyze and compare the influence of low-carbon policies on channel coordination for the foul＂ low-carbon policies. Numerical experiments are conducted to examine our findings.

关键词： Carbon emission low-carbon policy carbon quotas supply chain coordination quantitydiscount

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Posterior Cramer-Rao lower bounds for multitarget bearings-only tracking

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Journal of Systems Engineering and Electronics 2008年第6期19卷 1127-1132页

作者： Guo lei Tang Bin Liu gang Xiao Fei School of Physical Electronics Univ. of Electronic Science and Technology of China Chengdu 610054 P. R. China National Key Laboratory of Information Integrated Control Chengdu 610036 P. R. China

Usually, only the Cramer-Rao lower bound （CRLB） of single target is taken into consideration in the state estimate of passive tracking systems. As for the case of multitarget, there are few works done due to its complexity. The recursion formula of the posterior Cramer-Rao lower bound （PCRLB） in multitarget bearings-only tracking with the three kinds of data association is presented. Meanwhile, computer simulation is carried out for data association. The final result shows that the accuracy probability of data association has an important impact on the PCRLB.

关键词： multiple target tracking bearings-only tracking posterior Cramer-Rao lower bounder data association.

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Friction-condition-dependent sulfide and sulfate evolution on dialkylpentasulfide tribofilm studied by XANES

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Friction 2020年第5期8卷 874-881页

作者： Ganlin zheng Tongmei DING Songhong PANG lei zheng Tianhui REN Key Laboratory for Thin Film and Microfabrication of the Ministry of Education School of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100039China

The effects of friction conditions, such as rotational speed, frictional time, and applied load, on the evolution mechanism of sulfide and sulfate on the top and bottom layers of tribofilm were investigated by total electron yield (TEY) and fluorescence yield (FY) mode X-ray absorption near-edge structure (XANES) spectra in the same beam line (4B7A). The results demonstrated that the top and bottom layers of tribofilms were covered by sulfide and sulfate. The addition of dialkylpentasulfide (DPS) could form complex nonuniform tribofilm. In addition, the friction condition (speed, load, or time) has its unique role in the generation of sulfide and sulfate at a specific depth on the tribofilm surface. The enhancement of friction conditions could promote the sulfur tribochemical reaction in a comparatively large range and alter the relative intensity of sulfurization and the sulfur-oxidizing process.

关键词： sulfur X-ray absorption near-edge structure(XANES) friction condition tribochemical process

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Elemental Partitioning Characteristics of Equilibrium Phases in Inconel 718 Alloy at 600-1100℃

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Journal of Iron and Steel Research International 2013年第6期20卷 88-94页

作者： WEI Xian-ping zheng Wen-jie SONG Zhi-gang lei Ting YONG Qi-long XIE Qing-cheng Faculty of Metallurgical and Energy Engineering Kunming University of Science and Technology Central Iron and Steel Research Institute No.704 Institute of China Shipbuilding Industry Corporation

The optimization of heat treatment and chemical composition for Inconel 718 alloy has been investigated uninterruptedly because of its excellent mechanical properties and metallurgical *** species , chemical compositions and content of equilibrium phases of Inconel 718alloy in the temperature range of 600-1 100℃ were calculated by using thermodynamic software ＂ Thermo-Calc ＂ and the latest relevant datebase of Ni-base superalloys.A concept of elemental partitioning fraction was used to study the partitioning characteristics of alloying elements in each equilibrium phase at different temperatures , such as Ni , Cr , Fe , Nb , Mo , Al , Ti and C , and some calculation results were confirmed under a scanning transmission electron microscope （ STEM ） .The results showed that the elemental partitioning characteristics with the change of temperature revealed the selective partitioning characteristic of alloying elements in equilibrium phases at different temperatures , such as Nb was mainly distributed in δ and γ′phase , C in carbides , Al and Ti in γ′phase and Cr , Mo in Laves *** the same time , the effect of the change of component and quantity for each precipitated phase on matrix phase can be helpfully understood , which provided a theoretic foundation to optimize the chemical composition and heat treatment in different environments for Inconel 718alloy.

关键词： Inconel 718alloy Thermo-Calc thermodynamic calculation elemental partitioning fraction

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