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Efficient optimization method for variable-specific-impulse low-thrust trajectories with shutdown constraint

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Science China(Technological Sciences) 2022年第3期65卷 581-594页

作者： JIA FeiDa qiao Dong HAN hongwei LI XiangYu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information TechnologyBeijing 100081China

This paper develops a sequential convex programming(SCP)-based method to solve the minimum-fuel variable-specific-impulse low-thrust transfer problem considering shutdown constraint,with emphasize on improving the computational efficiency.The variable parameter engine is more applicable for many low-thrust scenarios,therefore,both a continuously variable model and a ladder variable model are adopted.First,the original problem is convexified by processing the constraint feasible domain,which is composed of the nonlinear dynamic equations and second-order equality constraint,into convex sets.Then,the approximation is generated to close the optimal solution of the low-thrust problem by iteratively solving the convexified subproblem.Moreover,the switching self-detection and adaptive node refinement methods are presented,which can improve the accuracy of the solution and accelerate the convergence during the approximation process and is especially necessary and effective in the scenarios with shutdown constraint.In numerical simulations,the comparison with the homotopic approach shows that the proposed method only needs 4%computational time as that of the homotopic approach,and two variable-specificimpulse examples further demonstrate the effectiveness and efficiency of the proposed method.

关键词： low-thrust trajectory variable-specific-impulse shutdown constraint sequential convex programming switching self-detection and adaptive node refinement

In situ phase transitional polymeric vaccines for improved immunotherapy

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National Science Review 2022年第2期9卷 99-108页

作者： Jie Wang Yi Wang Shenglin qiao Muhetaerjiang Mamuti hongwei An Hao Wang CAS Center for Excellence in Nanoscience CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety National Center for Nanoscience and Technology (NCNST) Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences

Cancer vaccines have exhibited immense potential in cancer treatment.Through activating the host’s immune system,vaccines stimulate extensive functional T cells to eliminate cancer.However,the therapeutic efficacy of cancer vaccines is limited by their inferior lymph node delivery and inadequate uptake of dendritic cells.Herein,we propose an in situ phase transitional strategy on vaccine manufacturing to maximally enhance lymph node drainage while ensuring adequate dendritic cell uptake.The phase transitional vaccines,with dynamic size modulation property,retain a small size(24.4±3.1 nm) during lymph node draining then transform into larger particles(483.0±41.6 nm) on-site by external signal input.Results show that this strategy induced rapid and robust immune response in a mouse melanoma tumor model.Furthermore,a stronger humoral immune response was observed in mice when immunized with MHC-Ⅱ restricted antigen,which demonstrated that lymph node-targeted cancer vaccine delivery could be effe ctively manipulated through dynamic size modulation.

关键词： nanomedicine lymph node delivery cancer vaccine size modulation dendritic cell

Chloride-intercalated continuous chemical vapor deposited graphene film with discrete adlayers

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Nano Research 2018年第1期11卷 440-448页

作者： qiao Chen Li Zhang hongwei Zhu State Key Lab of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China Center for Nano and Micro Mechanics Tsinghua University Beijing 100084 China

Heteroatom doping can open the bandgap and increase the carrier density, thus extending the applications of graphene. Iron chloride （FeC13） intercalation has proven to be an efficient method for the heavy doping of graphene. In this study, we prepared continuous chemical vapor deposited graphene （CVD-G） consisting of hexagonal adlayer domains to study the FeC13 intercalation. The structure of the FeC13-treated CVD-G was easily characterized via atomic force microscopy because of the change in the interlayer distance. FeC13 crystals several nanometers thick were integrated with the graphene surface, and FeC13 layer flakes were intercalated between the CVD-G adlayers. The G-band position and two-dimensional band shape in the Raman spectra confirmed the intercalation of the FeC13 between the graphene layers. The FeCI~ intercalation increased the electrical conductivity of the CVD-G with a well-maintained transmittance, which could be beneficial for a sensitive photodetector.

关键词： intercalation,graphene,chemical vapor deposition,iron chloride

Modulating MAPbI3 perovskite solar cells by amide molecules:Crystallographic regulation and surface passivation

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Journal of Energy Chemistry 2021年第5期30卷 179-185页

作者： Jin Xie Ziren Zhou Hongwei Qiao Mengjiong Chen Lijie Wang Shuang Yang Yu Hou Huagui Yang Key Laboratory for Ultrafine Materials of Ministry of Education Shanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China

A controllable crystallization is of practical importance to produce high-quality perovskite thin films with reduced structural defects.Lewis bases as electron-pair donor chemicals can strongly coordinate to lead ions and have been extensively employed to manipulate the growth of perovskite crystals.In this work,we demonstrate a series of Lewis-base amides,for morphological regulation of methylammonium lead triiodide(MAPbI3)thin films.The screened acetamide was demonstrated to decently improve the grain size,along with a spatial distribution at grain boundaries(GBs).The mesostructured solar cells of acetamide-modified absorbers yielded an optimized power conversion efficiency(PCE)of 20.04%with a mitigated open-circuit voltage(V_(OC))deficit of 0.39 V.This work provides a facile and cost-effective strategy toward controllable fabrication of high-performance MAPbI3 solar cells.

关键词： Amide Methylammonium lead triiodide Crystallization Solar cell

The effects of inactivated SARS-CoV-2 vaccination and subsequent infection of pregnant mice on the behaviors of offspring

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Animal Models and Experimental Medicine 2022年第5期5卷 430-435页

作者： Kaili Lin Meixuan Liu Lu Sun Hongwei Qiao Shunyi Wang Sidan Pan Hanjun Fu Jingzhu Wang Qiang Wei Hong Gao Institute of Laboratory Animal Science Chinese Academy of Medical Sciences and Comparative Medicine CenterPeking Union Medical CollegeBeijingChina

The mass inoculation of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccines to induce herd immunity is one of the most effective measures we can deploy in the fight against coronavirus disease 2019(COVID-19).Pregnant women are prone to a higher risk of COVID-19,and maternal infection is a risk fac-tor for a range of neurological disorders leading to abnormal behavior in adulthood.However,there are limited clinical data to support whether vaccination or infection post-immunization in pregnant women can affect the behavioral cognition of fetuses in adulthood.In this study,human angiotensin-converting enzyme 2 pregnant mice(F0 generation)were immunized with CoronaVac and then infected with SARS-CoV-2.Subsequently,we analyzed the behavioral cognition of their adult offspring(F1 gen-eration)using the open-field test and Morris water maze test.The adult F1 generation did not exhibit any impairments in spontaneous locomotor activity or spatial refer-ence memory.

关键词： offspring spatial reference memory spontaneous locomotor activity

Laboratory biosafety emergency management for SARS-CoV-2

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Journal of Biosafety and Biosecurity 2020年第2期2卷 99-101页

作者： Kaili Lin Meixuan Liu Haoran Ma Sidan Pan Hongwei Qiao Hong Gao Institute of Laboratory Animal Sciences Chinese Academy of Medical Sciences&Comparative Medicine CenterPeking Union Medical CollegeBeijing 100021China

A biosafety laboratory is a prerequisite for studying emerging infectious diseases.Safe and effective operation in laboratories and the handling of pathogens determine the safety of the personnel,pathogens,and the environment in the laboratory,which are among the key factors for successful experimentation.In this article,we aimed to provide ideas for the emergency management of biosafety laboratories,including a discussion on the urgency of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)related experimental activities,tracking clinical information,taking emergency measures,revision of the risk assessment process,and standardization of personal protective equipment and personnel behavior standards.

关键词： SARS-CoV-2 Biosafety Laboratory Emergency Management

Is there a great unconformity between Xiamaling and Longshan formations in the North China Craton?

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Science China Earth Sciences 2023年第5期66卷 959-984页

作者： hongwei KUANG Nan PENG Yongqing LIU Yuchong WANG Mingming CUI Xiaoshuai CHEN Dawei qiao Keining QI Institute of Geology Chinese Academy of Geological SciencesBeijing100037China School of Earth Science and Mapping Engineering China University of Mining and Technology(Beijing)Beijing100083China School of Resource and Environmental Engineering Hefei University of TechnologyHefei230009China

The existence of a 0.3 Ga"great unconformity"between the Mesoproterozoic"Undefined System"Xiamaling Formation and the"Neoproterozoic"Longshan Formation has long been controversial.In this study,stratigraphy,sedimentology,detrital zircon dating,lithium isotope,and major and trace elements were applied to systematically analyze their relationship.Results demonstrate that coarse to fine sandstone-mudstone normal cycles with different grades and thicknesses exist from the Xiamaling to the Longshan formations.Sedimentary succession formed from a restricted platform with lagoon-shallow marine shelf-tidal flat-beach and tidal shoal developing in ascending order.The pebbly sandstone at the bottom of the Long shan Formation does not have the properties of basal conglomerate with tectonic significance.The youngest detrital zircon is older than 1.6 Ga for the Long shan Formation and overlying Jing'eryu Formation sandstones.In addition,no(zircon)provenance has been found from the large igneous province of 1.32-1.2 Ga in Xiamaling Formation.Theδ^(7)Li isotope values exhibit a gradually increasing trend.The Li content and CIA(Chemical index of alteration)gradually decreases from the top of the Xiamaling Formation to the lower part of the Long shan Formation.Simultaneously,as K_(2)O/Al_(2)O_(3)and FeO/Fe_(2)O_(3)decreases,Na_(2)O/Al_(2)O_(3)increases,and Li/Al,V/Cr,and V/(V+Ni)fluctuates slightly.At the boundary,the Ce/Ce^(*)and Eu/Eu^(*)show positive and negative anomalies,respectively.Further,the Rb/Sr and Al/Si values decrease,and U/Th values increase.This indicates that the geochemistry of the weathering crust at the interface of the Xiamaling Formation-Long shan Formation is not characteristic.However,it indicates a weakening of continental weathering intensity from the bottom to the top of the interface.These results do not support the existence of a large unconformity between the Xiamaling and the Longshan formations.Therefore,it is suggested that the Long shan Formation-Jing'eryu Formation should be moved to the lower l

关键词： North China Craton Mesoproterozoic Transition period Unconformity Continuous sedimentation

Heterojunction solar cells based on graphene woven fabrics and silicon

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Journal of Materiomics 2018年第2期4卷 135-138页

作者： Yujia Zhong Yequan Xiao qiao Chen hongwei Zhu State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringCenter for Nano and Micro MechanicsTsinghua UniversityBeijing 100084China

Graphene-on-semiconductor has been proved to be a quality heterojunction with efficient photoelectric conversion.In this work,we constructed Schottky junction solar cells by combing graphene woven fabrics(GWFs)and n-doped single crystal silicon,and examined the performance of solar cells when GWFs of different meshes were used.Sparse GWFs possessed high optical transparency but led to poor carrier collection,whereas dense GWFs could collect carriers efficiently but generated too few photo carriers due to low transparency.The GWFs with an optimal mesh could provide a good balance between the generation and collection of photo-induced carriers to deliver high power conversion efficiency.

关键词： Graphene Heterojunction Solar cell

Photoluminescence properties of Tm^(3+)/Tb^(3+)/Sm^(3+) tri-doped Na_(5)Y_(9)F_(32) single crystal with high thermal stability for white light-emitting diodes

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Journal of Rare Earths 2021年第5期39卷 512-519页

作者： Yang qiao Xiong Zhou Jianli Zhang Haiping Xia hongwei Song Baojiu Chen Key Laboratory of Photo-electronic Materials Ningbo UniversityNingbo 315211China State Key Laboratory on Integrated Optoelectronics College of Electronic Science and Engineering and College of PhysicsJilin UniversityChangchun 130012China Department of Physics Dalian Maritime UniversityDalian 116026China

A novel Tm^(3+)/Tb^(3+)/Sm^(3+)tri-doped Na_(5)Y_(9)F_(32)single crystal was synthesized by a modified Bridgman method for the propose of white light emitting diodes.The fluorescence spectra of various Sm^(3+)ion concentrations and fixed 0.4 mol%Tm^(3+)and 0.5 mol%Tb^(3+)were measured and studied systematically excited by near-ultraviolet light of 355 nm.The Sm3+ion concentration takes apparent effect on the relative intensity of peaks in the visible region and the color coordinate combining from these emission bands.A near pure white light emission with color coordinates(0.3295,0.3057)and color temperature(5657 K)can be obtained when the concentrations of Tm^(3+),Tb^(3+)and Sm^(3+)ions are 0.4 mol%,0.5 mol%and 0.8 mol%,respectively.Furthermore,the practical down-conversion internal quantum yield was measured by integrating spheres at about 14.39%.The tri-doped Na_(5)Y_(9)F_(32)single crystal shows a high thermal stability inferring from the temperature dependent emission in which the integrated emission intensities are reduced only by^3%with the increase of temperature from 280 to 450 K.The present results demonstrate that the Tm^(3+)/Tb^(3+)/Sm^(3+)tri-doped Na_(5)Y_(9)F_(32)single crystal may provide a promising candidate for white light-emitting diodes,luminescent materials and fluorescent display devices.

关键词： Na_(5)Y_(9)F_(32)single crystal Tm^(3+)/Tb^(3+)/Sm^(3+) Bridgman method White light emission Rare earths