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Nonstationary channel model of reentry plasma sheath for spacecraft: Overview, parameter estimation, and perspective

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Chinese Journal of Aeronautics 2024年第10期37卷 26-49页

作者： Lei SHI Zongyuan liu Weimin BAO bo YAO Yifan WANG xiaoping LI Yanming liu Fangyan LI School of Aerospace Science and Technology Xidian UniversityXi’an 710126China Key Laboratory of Equipment Efficiency in Extreme Environment Ministry of EducationXi’an 710126China China Aerospace Science and Technology Corporation Beijing 100048China

The Tracking,Telemetering,and Command(TT&C)communication of spacecraft faces severe limitations during *** Electromagnetic(EM)propagation channel is influenced by changes in the flight state and fluid *** addition to the high-speed spatial channel,the Plasma Sheath Channel(PSC),which covers the surface of spacecraft,exhibits unique nonstationary and highly dynamic time-varying *** absence of a channel model for the reentry process of spacecraft negatively impacts the quality evaluation and system design of TT&C *** paper summarizes the methods for nonstationary PSC modeling,involving calculation methods for attenuation and phase shift in the channel,as well as a multistate nonstationary channel statistical model based on a hidden Markov ***,the correlation between amplitude variation and phase variation with electron density is *** paper also provides statistical characteristics of the channel and channel parameters at typical frequencies in the S/C/X/Ka *** findings serve as a reference for the design and evaluation of TT&C communication systems for reentry ***,the paper discusses the prospects of various aspects related to the channel characteristics and modeling of spacecraft PSCs in the shortwave and terahertz/laser bands,as well as the potential challenges in cross-domain spacecraft channel sensing and prediction.

关键词： Spacecraft Plasma sheaths Electromagnetic wave transmission Communication channels Channel estimation

Microstructure and properties of novel Al-Ce-Sc,Al-Ce-Y,Al-Ce-Zr and Al-Ce-Sc-Y alloy conductors processed by die casting,hot extrusion and cold drawing

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Journal of Materials Science & Technology 2020年第23期58卷 155-170页

作者： Weiyi Wang Qinglin Pan Geng Lin xiaoping Wang Yuqiao Sun Xiangdong Wang Ji Ye yuanwei Sun Yi Yu Fuqing Jiang Jun Li Yaru liu School of Materials Science and Engineering Central South UniversityChangsha 410083China Light Alloy Research Institute Central South UniversityChangsha 410083China Hunan Oriental Scandium Industry Co. Ltd.Changsha 410100China Manufacturing Center CRRC Times Electric Co.Ltd.Zhuzhou 412001China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China The Second Xiangya Hospital Central South UniversityChangsha 410011China

In order to overcome the trade-off between the strength and electrical conductivity of aluminum alloy conductors,the new Al-Ce-Sc,Al-Ce-Y,Al-Ce-Zr and Al-Ce-Sc-Y alloys were prepared by die casting,high temperature homogenization treatment,hot extrusion and cold *** Sc and Y eliminated the dendrite segregation of the as-cast Al-0.2 Ce alloy and promoted the formation of equiaxed grains with the average grain size of 142.5μ*** Al-0.2 Ce-0.2 Sc-0.1 Y alloy inherited the great tensile properties of Al-0.2 Ce-0.2 Sc alloy and the high electrical conductivity of Al-0.2 Ce-0.1 Y alloy *** cold drawing and annealing at 200℃for 5 h,the ultimate tensile strength of Al-0.2 Ce-0.2 Sc-0.1 Y alloy reached 200 MPa and 198 MPa,the elongation reached 6.8%and 8.5%,and the electrical conductivity reached 61.01%and 61.77%,*** main second phase of Al-0.2 Ce-0.2 Sc-0.1 Y alloy after hot extrusion were Al_(13)Fe_3 Ce containing a few Y and Si *** larger size and proportion of the second phase greatly reduced the concentration of solute Fe and Si atoms and the addition of Y significantly decreased the density of defects after cold drawing compared to Al-0.2 Ce-0.2 Sc alloy,which improved electrical conductivity of the ***,the dispersed and coherent nano-size Al_3 Sc precipitions of Al-0.2 Ce-0.2 Sc-0.1 Y alloy greatly improved strength,elongation and heat *** with Al-0.2 Ce-0.2 Sc alloy,the lower density of dislocation,stacking fault and subgrain boundary and the larger size of Al_3 Sc precipitions with enrichment of Y atoms enable the Al-0.2 Ce-0.2 Sc-0.1 Y alloy to maintain high strength,elongation and electrical conductivity after annealing.

关键词： Al-Ce-Sc-Y alloy Electrical conductivity Mechanical properties Second phase Nano-size precipitates

Genome-wide analysis of expansins and their role in fruit spine development in cucumber(Cucumis sativus L.)

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Horticultural Plant Journal 2022年第6期8卷 757-768页

作者： xiaoping liu Shaoyun Dong Han Miao Kailiang bo Caixia Li Yingying Yang Xingfang Gu Shengping Zhang Institute of Vegetables and Flowers Chinese Academy of Agricultural SciencesBeijing 100081China

Cucumber is one of the most widely consumed vegetables worldwide,and the fruit spine is an important fruit quality *** play critical roles in fruit development;however,the regulation of expansins in cucumber fruit spine development has not been *** this study,33 expansin genes were identified in the cucumber genome V3;additionally,expansin genes in Citrullus lanatus,Cucumis melo,Cucurbita maxima,Lagenaria siceraria,and Benincasa hispida were also *** analysis of expansin proteins in Cucurbitaceae and Arabidopsis showed that they evolved separately in each plant *** analysis showed that *** was derived earlier than the other five Cucurbitaceae *** expression of CsEXPA2,CsEXPA14,and CsEXLA3 varied in cucumber lines with different fruit spine densities.A yeast two-hybrid assay showed that a putative auxin transporter encoded by numerous spine gene(ns)interacts with CsEXLA2,which may be involved in the development of the numerous spines in *** results provide novel insights into the expansins related to plant development and fruit spine development in cucumber.

关键词： Cucumber Expansins Phylogenetic analysis Collinearity Gene expression Fruit spine

Superhydrophobicity and high corrosion resistance of secondary alkane sulphonate(SAS) modified Li-Al LDH film in-situ grown on aluminum alloy

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Corrosion Communications 2023年第1期9卷 27-35页

作者： Xinyu Pan Xiaohu Luo Ji Li xiaoping Zhang Xihong Yu Chengliang Zhou bo Chen Yali liu College of Chemistry and Chemical Engineering Hunan University Guizhou General Colleges and Universities of Engineering Research Center of Corrosion and Anticorrosion of Materials SINOPEC Beijing Research Institute of Chemical Industry Sokan Research Institute of Advanced Surface Treatment and Functional Coatings

In this work, a secondary alkane sulfonate（SAS） modified Li-Al LDH film（SLDH） with high corrosion resistance by a simple in-situ growth on aluminium alloy 6N01. Water contact angle（WCA） and scanning electron microscopy（SEM） revealed that the film was fabricated with a flower-shaped microstructure and highly superhydrophobic performance（WCA = 153°）. XRD patterns and FTIR spectrum revealed that SAS species were intercalated into SLDH. X-ray photoelectron spectroscopy（XPS） analysis indicated that SLDH was mainly composed of C, O, S, Al and Li. Potentiodynamic polarization（PDP） curves proved that SLDH(icorr= 9.169 × 10-8A/cm2) provided pronounced protection than that of CLDH(icorr= 9.011 × 10-7A/cm2), and electrochemical impedance spectra（EIS） demonstrated that corrosion resistance was improved. Neutral salt spray（NSS） tests exhibited that compared to CLDH with severe pitting corrosion, SLDH was virtually undamaged after 360 h exposure. Based on the above results, a sound inhibition mechanism of SLDH was inferred to be a dual effect, including the barrier action of superhydrophobic surface and the ion exchange of intercalated SAS with aggressive chlorides. In conclusion, the special divergent long-chain structure of SAS with low surface energy results in the superhydrophobicity of SLDH.

关键词： LDH SAS Superhydrophobicity High corrosion resistance

Aging amorphous/crystalline heterophase PdCu nanosheets for catalytic reactions

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National Science Review 2019年第5期6卷 955-961页

作者： Hongfei Cheng Nailiang Yang Xiaozhi liu Qinbai Yun Min Hao Goh bo Chen Xiaoying Qi Qipeng Lu xiaoping Chen Wen liu Lin Gu Hua Zhang Center for Programmable Materials School of Materials Science and EngineeringNanyang Technological University State Key Laboratory of Biochemical Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences School of Physical Sciences University of Chinese Academy of Sciences Singapore Institute of Manufacturing Technology A*STAR School of Materials Science and Engineering University of Science and Technology Beijing School of Chemical and Biomedical Engineering Nanyang Technological University Songshan Lake Materials Laboratory Department of Chemistry City University of Hong Kong

Phase engineering is arising as an attractive strategy to tune the properties and functionalities of *** particular, amorphous/crystalline heterophase nanostructures have exhibited some intriguing ***, the one-pot wet-chemical synthesis of two types of amorphous/crystalline heterophase Pd Cu nanosheets is reported, in which one is amorphous phase-dominant and the other one is crystalline *** the aging process of the synthesized Pd Cu nanosheets is studied, during which their crystallinity increases, accompanied by changes in some physicochemical *** a proof-of-concept application, their aging effect on catalytic hydrogenation of 4-nitrostyrene is *** a result, the amorphous phase-dominant nanosheets initially show excellent *** aging for 14 days, their catalytic activity is higher than that of crystalline phase-dominant *** work demonstrates the intriguing properties of heterophase nanostructures, providing a new platform for future studies on the regulation of functionalities and applications of nanomaterials by phase engineering.

关键词： amorphous/crystalline heterophase nanosheets aging selective hydrogenation catalysis

Electrically driven motion, destruction, and chirality change of polar vortices in oxide superlattices

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Science China(Physics,Mechanics & Astronomy) 2022年第3期65卷 77-84页

作者： Pan Chen Congbing Tan Zhexin Jiang Peng Gao yuanwei Sun Lifen Wang Xiaomei Li Ruixue Zhu Lei Liao Xu Hou Ke Qu Ning Li Xiaomin Li Zhi Xu Kaihui liu Wenlong Wang Jinbin Wang xiaoping Ouyang Xiangli Zhong Jie Wang Xuedong Bai Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China International Center for Quantum Materials Electron Microscopy LaboratorySchool of PhysicsPeking UniversityBeijing 100871China Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials School of Physics and ElectronicsHunan University of Science and TechnologyXiangtan 411201China Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China Collaborative Innovation Center of Quantum Matter Beijing 100871China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China State Key Laboratory for Artificial Microstructure&Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China School of Materials Science and Engineering Xiangtan UniversityXiangtan 411105China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang UniversityHangzhou 310027China

Topological polar vortices, which are electric analogs of magnetic objects, present great potential in applications of future nanoelectronics because of their nanometer size, anomalous dielectric response, and chirality. To enable the functionalities, it is prerequisite to manipulate the polar states and chirality by using external stimuli. Here, we probe the evolutions of polar state and chirality evolutions of topological polar vortices in Pb TiO;/Sr TiO;superlattices under an electric field by using atomically resolved in situ scanning transmission electron microscopy and phase-field simulations. We find that, under electric field, the chiral vortex cores can be moved laterally to form close-pair structures, transform into a/c domain stripes, and finally become a nonchiral c-domain. Such transition is reversible and spontaneous after bias removal. Interestingly, during switching and backswitching events, the vortex rotation can be changed, offering a potential strategy to manipulate vortex chirality. The revealed dynamic behavior of individual polar vortices at the atomic scale provides fundamentals for future device applications.

关键词： chirality polar vortex ferroelectrics in situ transmission electron microscopy phase-field simulations

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Integrating single Ni site and PtNi alloy on two-dimensional porous carbon nanosheet for efficient catalysis in fuel cell

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Nano Research 2024年第8期17卷 6916-6921页

作者： Fangyao Zhou Yaner Ruan Feng Li Lin Tian mengzhao Zhu Wenan Tie Xiaoyan Tian bo Wang Peigen liu Jie Xu xiaoping Gao Peng Li Huang Zhou Yuen Wu Key Laboratory of Precision and Intelligent Chemistry University of Science and Technology of ChinaHefei 230026China Shanxi Yanchang Petroleum(Group)Co.Ltd. Xian 710065China College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou 325035China

The performance of catalyst depends on the intrinsic activity of active sites and the structural characteristics of the ***,we simultaneously integrate single nickel(Ni)sites and platinum-nickel(PtNi)alloy nanoparticles(NPs)on a two-dimensional(2D)porous carbon nanosheet,demonstrating remarkable catalytic performance in the oxygen reduction reaction(ORR).The single Ni sites can activate the oxygen molecules into key oxygen-containing intermediate that is further efficiently transferred to the adjacent PtNi alloy NPs and rapidly reduced to H_(2)O,which establishes a relay catalysis between active *** porous structure on the carbon nanosheet support promotes the transfer of active intermediates between these active sites,which assists the relay catalysis by improving mass ***,the obtained catalyst demonstrates a half-wave potential of up to 0.942 V,a high mass activity of 0.54 A·mgPt^(−1),and negligible decay of activity after 30,000 cycles,which are all superior to the commercial Pt/C catalysts with comparable loading of *** theoretical calculation results reveal that the obtained catalyst with defect structure of carbon support presents enhanced relay catalytic effect of PtNi alloy NPs and single Ni sites,ultimately realizing improved catalytic *** work provides valuable inspiration for developing low platinum loading catalyst,integrating single atoms and alloy with outstanding performance in fuel cell.

关键词： two-dimensional porous carbon nanosheet Pt-based alloy single atom catalysts relay effect proton-exchange membrane fuel cells

Systematic co-delivery of dual agonists to enhance cancer immunotherapy

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Nano Research 2022年第9期15卷 8326-8335页

作者： Xiangxia Li Guiyuan Chen Yangyi Wang Lanhong Su bo Chen Kecheng Wu Yun Xing Zechenxi Song Ruike Dai Tianxin liu Jiaao Zhao Zhe Xie Peijie Zhou xiaoping Xia Yuanzeng Min Department of Chemistry University of Science and Technology of ChinaHefei 230026China The First Afffiliated Hospital of USTC Division of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230001China Anhui Provincial Children's Hospital Hefei 230051China Children's Hospital of Fudan University Anhui Hospital Hefei 230051China Children's Hospital of Anhui Medical University Hefei 230051China

In the tumor immunosuppressive microenvironment(TIME),antigen presenting cells(APCs)usually exhibit a tumor suppressor ***-like receptors(TLRs)agonists could reprogram M2-type macrophages to M1-type and stimulate dendritic cells(DCs)*** combination of TLR7/8 and TLR9 agonists seems to have synergistic therapeutic ***,we designed a lipid-coated mesoporous silica nanoparticle(MSNs@Lipo)for the co-delivery of TLR7/8 agonist resiquimod(R848)and TLR9 agonist CpG oligodeoxynucleotides(ODNs)(CpG@MSNs-R@L-M).R848 was firstly conjugated onto the nanoparticle via silane chemistry,which is acidic responsive drug ***,CpG was loaded onto the nanoparticle through the positive charge mainly from TLR7/8 agonist *** in vitro experiments further indicated that both drugs have acid-responsive release properties and could be taken up by DCs and located on the endosomes of *** importantly,CpG@MSNs-R@L-M could significantly improve the antitumor efficacy in B16F10 melanoma *** mechanistic study demonstrated that CpG@MSNsR@L-M could remarkably modulate the TIME by promoting the maturation of DCs and repolarizing macrophages from M2 to M1 phenotype and facilitating the infiltration of tumor cytotoxic T *** was concluded that in comparison to single agonist,the codelivery of dual agonists,CpG and R848,can improve anti-tumor immune responses for cancer immunotherapy.

关键词： toll-like receptors(TLRs)agonists mesoporous silica nanoparticles(MSNs) drug delivery tumor immunosuppressive microenvironment(TIME) cancer immunotherapy

Energetic electron detection packages on board Chinese navigation satellites in MEO

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Earth and Planetary Physics 2021年第2期5卷 158-179页

作者： YuGuang Ye Hong Zou Qiu-Gang Zong HongFei Chen JiQing Zou WeiHong Shi XiangQian Yu WeiYing Zhong YongFu Wang YiXin Hao ZhiYang liu XiangHong Jia bo Wang xiaoping Yang XiaoYun Hao School of Earth and Space Sciences Peking UniversityBeijing 100871China State Key Laboratory of Space Medicine Fundamentals and Application Chinese Astronaut Research and Training CenterBeijing 100093China Shandong Aerospace Electro-technology Yantai Shandong 264000China

Energetic electron measurements and spacecraft charging are of great significance for theoretical research in space physics and space weather *** this paper,the energetic electron detection package(EEDP)deployed on three Chinese navigation satellites in medium Earth orbit(MEO)is *** instrument was developed by the space science payload team led by Peking *** EEDP includes a pinhole medium-energy electron spectrometer(MES),a high-energy electron detector(HED)based onΔE-E telescope technology,and a deep dielectric charging monitor(DDCM).The MES measures the energy spectra of 50−600 keV electrons from nine directions with a 180°×30°field of view(FOV).The HED measures the energy spectrum of 0.5−3.0 MeV electrons from one direction with a 30°cone-angle *** ground test and calibration results indicate that these three sensors exhibit excellent *** observations show that the electron spectra measured by the MES and HED are in good agreement with the results from the magnetic electron-ion spectrometer(MagEIS)of the Van Allen Probes spacecraft,with an average relative deviation of 27.3%for the energy *** charging currents and voltages measured by the DDCM during storms are consistent with the highenergy electron observations of the HED,demonstrating the effectiveness of the *** observations of the EEDP on board the three MEO satellites can provide important support for theoretical research on the radiation belts and the applications related to space weather.

关键词： radiation belts energetic electron detection Pin-hole technology Chinese navigation satellites MEO internal charging