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Review on heat-to-power conversion technologies for hypersonic vehicles

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Chinese Journal of Aeronautics 2024年第5期37卷 148-179页

作者： Yinke QI xiaofeng ma Peixue JIANG Yinhai ZHU Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Beijing Key Laboratory of CO_(2)Utilization and Reduction Technology Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China

Hypersonic vehicles have enormous military and economic value,while their power and thermal protection demands will increase substantially with the rise in mach number and *** the tremendous high-quality heat on the vehicle surface and engine wall into electrical energy through heat-to-power technologies will not only play a role in thermal protection,but also supply power for the *** paper provides a comprehensive review of heat-to-power conversion technologies on hypersonic vehicles,including the indirect conversion of Brayton and Rankine cycles,direct conversion of thermoelectric materials,and combined *** the open Brayton cycle with hydrocarbon fuel as the working fluid,the Power-to-Weight Ratio(PWR)can achieve the highest,at around 1.8,due to the high PWR of the hydrocarbon fuel turbine and the few components of the ***,its work capacity is limited by the flow rate of the supplied *** closed Brayton cycle can maintain a relatively high PWR,ranging from 0.2 to 0.8,while achieving relatively high output power and conversion *** Rankine cycle has a higher PWR,its range is close to that of the closed Brayton cycle,peaking at about *** thermoelectric materials technology has a small power generation level,making it more suitable for scenarios with low power *** review provides a basis for selecting and developing heat-to-power conversion technologies on hypersonic vehicles.

关键词： Hypersonic vehicles Heat-to-power conversion Brayton cycle Rankine cycle Thermoelectric materials

Novel methanol-tolerant Ir-S/C chalcogenide electrocatalysts for oxygen reduction in DMFC fuel cell

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Particuology 2011年第2期9卷 155-160页

作者： Jingyu ma Desheng Ai xiaofeng Xie Jianwei Guo Institute of Nuclear & New Energy Technology Tsinghua University Beijing 100084 China

Novel methanol-tolerant oxygen-reduction catalysts, iridium-sulphur （Ir-S） chalcogenides with different Ir/S atomic ratios, were synthesized via a precipitation method using H2IrCI6 and Na2SO3 as the Ir and S precursors. Powder X-ray diffraction （XRD） and transmission electron microscopy （TEM） were used to characterize the lrxSl_x/C chalcogenide catalysts. Particle size ranging from 2.5 to 2.8 nm though obvi- ous agglomeration was found on carbon support. However, these chalcogenide catalysts showed strong catalytic activity towards the oxygen reduction reaction （ORR） and high methanol tolerance, strongly suggesting these novel catalysts as promising candidates for direct methanol fuel cell （DMFC） cathode applications.

关键词： DMFCIridiumSulphurCathodic catalystOxygen reductionMethanol tolerant

Phase-only pattern synthesis based on gradient-descent optimization

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Journal of Systems Engineering and Electronics 2016年第2期27卷 297-307页

作者： Chengjun Lu Weixing Sheng Yubing Han xiaofeng ma School of Electronic and Optical Engineering Nanjing University of Science and Technology

By applying phase-only technique in array antenna pattern synthesis, antenna arrays can form desired patterns with the use of phase shifters only. A novel phase-only pattern synthesis algorithm is proposed for the passive phased array seeker. This algorithm synthesizes the main beam of the antenna pattern through least-squares approximation, thus minimizing the errors between the actual and the desired main beams. The synthesis problem can be solved by applying gradient-descent optimization. The item for suppressing side lobes is added to the above synthesis problem. To obtain a side lobe level as low as possible, the algorithm assigns different weights to different directions in the side lobe region. The algorithm is run repeatedly and the weights are adjusted adaptively according to the normalized power in the side lobe directions. Detailed examples are presented to demonstrate the accuracy and effectiveness of the proposed approach.

关键词： pattern synthesis phase-only gradient-descent adaptively

Genesis of Fibrous Calcite in the Chang 7 Member of the Yanchang Formation,Ordos Basin,China

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Acta Geologica Sinica(English Edition) 2023年第5期97卷 1490-1502页

作者： LIU Guanglin LIU Xianyang ma xiaofeng ma Shuang WANG xiaofeng LI Shuo SHI Zhiqiang WANG Yanxin State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengdu 610059China National Engineering Laboratory for Low Permeability Oil and Gas Field Exploration and Development Xi’an 710018China Exploration and Development Research Institute of PCOC Xi’an 710018China PetroChina Changqing Oilfield Company(PCOC) Xi’an 710018China Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000China Geological Research Institute of the First Oil Production Plant of PCOC Xi’an 710018China Engineering Cost management Department of PCOC Xi’an 710018China

To explore the genesis of the laminated calcite veins developed in the black shale of Chang 73 submember of the Ordos Basin,the petrology,microstructure and geochemistry of calcite veins are studied using thin sections,fluid inclusions,trace elements and isotopic *** source,the time of formation,the mechanism of formation,and the dynamic background of the veins are *** veins are mostly made up of calcite,mixed with lenticular or spindle-shape solid wall rock *** structures are identified in the calcite minerals:fibrous,rhombic cleavage,and wedge-like *** elements and isotopes of carbon and oxygen confirm that the calcite veins were formed from a high density hydrothermal *** is assumed that calcite veins formed prior to wall rock consolidation during the formation of the Qinling Orogenic Belt in the Middle and Late *** results show that the sedimentary sources of Chang 73 submember were influenced by hydrothermal materials besides terrigenous *** fibrous calcite is different from the fibrous calcite reported in the morphology and mechanism of *** this way,the research complements and improves the morphology and the mechanism of formation of fibrous calcite.

关键词： fibrous calcite veins lacustrine black shale hydrothermal fluid Chang 7 member Ordos Basin

Shaped-Beam Pattern Synthesis Through the Construction of Weighted Generalized Rayleigh Quotient

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Chinese Journal of Electronics 2019年第1期28卷 207-214页

作者： YANG Yin WAN Chuan SHENG Weixing HAN Yubing ma xiaofeng School of Electronic and Optical Engineering Nanjing University of Science and Technology

A novel shaped-beam pattern synthesis method of generating an arbitrary footprint pattern under an arbitrary array structure is proposed. The embedded element pattern information is included in the pattern model, and a new cost function composed of three optimization items which are sidelobe levels,mainlobe ripples and mainlobe gains is constructed through the model. During the optimization process,to further enhance the performance of the synthesized pattern, a weight matrix is designed and added to the optimization items, then the generalized Rayleigh quotient approximation method is used to obtain the final array element excitations. To illustrate the good performance of the provided method, several synthesis examples with different arrays and footprints are presented. Compared with other algorithms such as Weighted alternating reverse projection(WARP) method, the proposed method can achieve better results with lower sidelobe levels, smaller mainlobe ripples and less computational load.

关键词： Pattern synthesis Embedded element pattern Mutual coupling Generalized Rayleigh quotient approximation Arbitrary footprint

Signal recovery method based on co-prime array

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Journal of Systems Engineering and Electronics 2017年第2期28卷 224-234页

作者： Shuang Qiu Weixing Sheng xiaofeng ma Yubing Han Renli Zhang School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNanjing 210094China

A signal waveform recovery method based on the co-prime array is investigated to extract the waveform of the desired signal from spatial interferences in narrowband scenarios. The direction of arrivals (DOAs) of the desired signal and interference signals are estimated with the compressive sensing approach based on angle grids, and the signal power together with the noise power are estimated. Thereafter, a modified steepest descent (SD) method is derived to recover the waveform of the desired signal and interferences utilizing the estimated power and directions. The recovered waveform of the desired signal is the output of the proposed method. The situation in which the signals are not on the predefined angle grids is also considered. The DOAs estimated via the predefined angle grids are corrected based on the maximum likelihood (ML) angle estimation. Compared to the existing beamforming methods on co-prime array, the proposed method can obtain the waveform of the desired signal. Simulation results demonstrate that the proposed method can achieve good performance in signal waveform recovery and output signal to noise ratio. © 2017 Beijing Institute of Aerospace Information.

关键词： Compressed sensing maximum likelihood maximum likelihood estimation Recovery Signal reconstruction Signal to noise ratio

Adaptive monopulse beamforming with partial parallel structure

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Journal of Systems Engineering and Electronics 2012年第6期23卷 802-814页

作者： Liang Chen Weixing Sheng xiaofeng ma Fei Huang and Yubing Han School of Electronic and Optical Engineering Nanjing University of Science and Technology Nanjing 210094 P. R. China

A new recursive algorithm with the partial parallel structure based on the linearly constrained minimum variance （LCMV） criterion for adaptive monopulse systems is proposed. The weight vector associated with the original whole antenna array is decomposed into several adaptive weight sub-vectors firstly. An adaptive algorithm based on the conventional LCMV principle is then deduced to update the weight sub-vectors for sum and difference beam, respectively. The optimal weight vector can be obtained after convergence. The required computational complexity is evaluated for the proposed technique, which is on the order of O（N） and less than that of the conventional LCMV method. The flow chart scheme with the partial parallel structure of the proposed algorithm is introduced. This scheme is easy to be implemented on a distributed computer/digital signal processor （DSP） system to solve the problems of the heavy computational burden and vast data transmission of the large-scale adaptive monopulse array. Then, the monopulse ratio and convergence rate of the proposed algorithm are evaluated by numerical simulations. Compared with some recent adaptive monopulse estimation methods, a better performance on computational complexity and monopulse ratio can be achieved with the proposed adaptive method.

关键词： digital beamforming monopulse estimation linearlyconstrainted minimum variance (LCMV) parallel distributed com-putation.

Gangliosides can decelerate accumulation of lipofusin in cultured nerve cells

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Chinese Science Bulletin 1998年第16期43卷 1405-1406页

作者： xiaofeng ma Jinfa Gu Zhentong Mei Shanghai Institute of Physiology Chinese Academy of Sciences Shanghai China

Investigates the effects of gangliosides on aging of cultured nerve cells. Intracellular autofluorescence intensities of each group on the seventh and fourteenth days of culture; Excitation and emission wavelength; Ce... 详细信息

关键词： Gangliosides can decelerate accumulation of lipofusin in cultured nerve cells

Synthesis and structure of 3D heterometallic (3d-4f) coordination polymers:{[Ln_2Cu(pydc)_4(H_2O)_6]·2H_2O}_n

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Chinese Science Bulletin 2009年第23期54卷 4291-4295页

作者： ma JingXin HUANG xiaofeng WEI RuiPing LIU WeiSheng College of Chemistry and Chemical Engineering Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of GansuProvince Lanzhou University Lanzhou 730000 China

Two new 3D heterometallic (3d-4f) coordination polymers {[Ln2Cu(pydc)4(H2O)6]·2H2O}n [Ln = Eu (1) and Gd (2)] have been synthesized by hydrothermal reactions and characterized by elemental analysis, X-ray single-crystal analyses, and IR spectroscopy. X-ray crystal structure analyses show that 1 and 2 possess 3D networks and strong intramolecular hydrogen bonding interactions which was confirmed by thermogravimetric (TG) analysis.

关键词：水热合成反应晶体结构分析配位聚合物三维网络分子内氢键元素分析红外光谱单晶分析