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Space/Air Covert Communications:Potentials,Scenarios,and Key Technologies

China Communications 2024年第3期21卷 1-18页

作者： Mao Haobin Liu Yanming zhu Lipeng Mao Tianqi Xiao zhenyu Zhang Rui Han zhu Xia Xianggen School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore School of Science and Engineering Shenzhen Research Institute of Big Datathe Chinese University of Hong KongShenzhenGuangdong 518172China Department of Electrical and Computer Engineering University of HoustonHoustonTX 77004USA Department of Computer Science and Engineering Kyung Hee UniversitySeoulSouth Korea446-701 Department of Electrical and Computer Engineering University of DelawareNewarkDE 19716USA

Space/air communications have been envisioned as an essential part of the next-generation mobile communication networks for providing highquality global connectivity. However, the inherent broadcasting nature of wireless propagation environment and the broad coverage pose severe threats to the protection of private data. Emerging covert communications provides a promising solution to achieve robust communication security. Aiming at facilitating the practical implementation of covert communications in space/air networks, we present a tutorial overview of its potentials, scenarios, and key technologies. Specifically, first, the commonly used covertness constraint model, covert performance metrics, and potential application scenarios are briefly introduced. Then, several efficient methods that introduce uncertainty into the covert system are thoroughly summarized, followed by several critical enabling technologies, including joint resource allocation and deployment/trajectory design, multi-antenna and beamforming techniques, reconfigurable intelligent surface(RIS), and artificial intelligence algorithms. Finally, we highlight some open issues for future investigation.

关键词： artificial intelligence(AI) sixth generation(6G) space-air-ground integrated networks(SAGINs) space/air covert communications

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Ancient mitochondrial genome depicts sheep maternal dispersal and migration in Eastern Asia

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Journal of Genetics and Genomics 2024年第1期51卷 87-95页

作者： Liu Yang Xing Zhang Yaning Hu Piao zhu Hua Li zhenyu Peng Hai Xiang Xinying Zhou Xingbo Zhao National Engineering Laboratory for Animal Breeding Key Laboratory of AnimalGeneticsBreeding and ReproductionMinistry of Agriculture and Rural AffairsCollege of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193China Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding School of Life Science and EngineeringFoshan UniversityFoshanGuangdong 528225China State Key Laboratory of Agricultural Genomics BGI-ShenzhenShenzhenGuangdong 518083China Key Laboratory of Vertebrate Evolution and Human Origins Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044China

Sheep have been one of the most important groups of animals since ancient times.However,the knowledge of their migration routes and genetic relationships is still poorly understood.To investigate sheep maternal migration histories alongside Eurasian communications routes,in this study,we obtain mitochondrial genomes(mitogenomes)from 17 sheep remains in 6 Chinese sites and 1 Uzbekistan site dated 4429–3100 years before present(BP).By obtaining the mitogenomes from the sheep(4429–3556 BP)found in the Tongtian Cave site in Xinjiang,Altai region of northwest China,our results support the emergence of haplogroup C sheep in Xinjiang as early as 4429–3556 BP.The combined phylogenetic analyses with extant ancient and modern sheep mitogenomes suggest that the Uzbekistan-Altai region may have been a migration hub for early sheep in eastern Asia.At least two migration events have taken place for sheep crossing Eurasia to China,one passing by Uzbekistan and Northwest China to the middle and lower reaches of the Yellow River at approximately 4000 BP and another following the Altai region to middle Inner Mongolia from 4429 BP to 2500 BP.Overall,this study provides further evidence for early sheep utilization and migration patterns in Eastern Asia.

关键词： Sheep Ancient DNA Eastern Asia Mitochondrial genome Migration Altai

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Sustainable all-weather CO2 utilization by mimicking natural photosynthesis in a single material

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National Science Review 2024年第2期11卷 177-187页

作者： Xianjin Shi Yu Huang Ran Long zhenyu Wang Liqin Wang Junji Cao Gangqiang zhu Yujie Xiong State Key Laboratory of Loess and Quaternary Geology(SKLLQG) Key Laboratory of Aerosol Chemistry and Physics Institute of Earth EnvironmentChinese Academy of Sciences Center of Excellence in Quaternary Science and Global Change Chinese Academy of Sciences University of Chinese Academy of Sciences Hefei National Research Center for Physical Sciences at the Microscale School of Chemistry and Materials Science and National Synchrotron Radiation Laboratory University of Science and Technology of China Institute of Atmospheric Physics Chinese Academy of Sciences School of Physics and Information Technology Shaanxi Normal University

Solar-driven CO2conversion into hydrocarbon fuels is a sustainable approach to synchronously alleviating the energy crisis and achieving net CO2emissions.However,the dependence of the conversion process on solar illumination hinders its practical application due to the intermittent availability of sunlight at night and on cloudy or rainy days.Here,we report a model material of Pt-loaded hexagonal tungsten trioxide（Pt/h-WO3） for decoupling light and dark reaction processes,demonstrating the sustainable CO2conversion under dark conditions for the first time.In such a material system,hydrogen atoms can be produced by photocatalytic water splitting under solar illumination,stored together with electrons in the h-WO3through the transition of W6+to W5+and spontaneously released to trigger catalytic CO2reduction under dark conditions.Furthermore,we demonstrate using natural light that CH4production can persist at night and on rainy days,proving the accomplishment of all-weather CO2conversion via a sustainable way.

关键词： sustainable CO2 utilization artificial photosynthesis all-weather application charge storage

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Novel P-doping-tuned Pd nanoflowers/S,N-GQDs photo-electrocatalyst for high-efficient ethylene glycol oxidation

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Chinese Chemical Letters 2024年第6期35卷 541-545页

作者： Xiaoxiao Huang Zhi-Long He Yangpeng Chen Lei Li zhenyu Yang Chunyang Zhai Mingshan zhu School of Materials Science and Chemical Engineering Ningbo UniversityNingbo 315211China College of Biological Chemical Sciences and EngineeringJiaxing UniversityJiaxing 314001China Guangdong Key Lab oratory of Environmental Pollution and Health School of EnvironmentJinan UniversityGuangzhou 510632China

Traditional photo-electcatalyst structures of small noble metal nanoparticles assembling into large-scale photoactive semiconductors still suffer from agglomeration of noble metal nanoparticles,insufficient charge transfer,undesirable photoresponse ability that restricted the photo-electrocatalytic performance.To this end,a novel design strategy is proposed in this work,namely integrating small-scale photoactive materials(doped graphene quantum dots,S,N-GQDs)with large-sized noble metal(Pd P)nanoflowers to form novel photo-electrocatalysts for high-efficient alcohol oxidation reaction.As expected,superior electrocatalytic performance of Pd P/S,N-GQDs for ethylene glycol oxidation is acquired,thanks to the nanoflower structure with larger specific surface area and abundant active sites.Furthermore,nonmetal P are demonstrated,especially optimizing the adsorption strength,enhancing the interfacial contact,reducing metal agglomeration,ensuring uniform and efficient doping of S,N-GQDs,and ultimately significantly boost the catalytic activity of photo-electrocatalysts.

关键词： Non-metallic P–doping Sulfur nitrogen co-doped graphene quantum dots Pd nanoflowers Photo-electrocatalytic Ethylene glycol oxidation

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Carotenoid isomerase regulates rice tillering and grain productivity by its biosynthesis pathway

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Journal of Integrative Plant Biology 2024年第2期66卷 172-175页

作者： Chaoqing Ding Zhengji Shao Yuping Yan Guangheng Zhang Dali Zeng Li zhu Jiang Hu zhenyu Gao Guojun Dong Qian Qian Deyong Ren State Key Laboratory of Rice Biology and Breeding ChinaNational Rice Research InstituteHangzhou 310006China

Tillers are unique inflorescence-like branches in grasses,and their number determines the panicle number,plant architecture,and yield(Shang et al.,2021).Tiller formation mainly undergoes axillary meristem(AM)initiation and tiller bud outgrowth(Wang et al.,2018;Yan et al.,2023).The rice(Oryza sativa)KNOX gene OSH1 is expressed in AMs,and an osh1 mutant produces fewer tillers(Tanaka et al.,2015).

关键词： sativa Oryza panicle

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Highly efficient ternary organic solar cells with excellent open-circuit voltage and fill factor via precisely tuning molecular stacking and morphology

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Science China Chemistry 2024年第3期67卷 963-972页

作者： Dinghong Sun zhenyu Chen Jianfeng Zhang Wei Song Jingyu Shi Jintao zhu Yuanyuan Meng Fei Jin Shuncheng Yang Ziyi Ge Faculty of Electrical Engineering and Computer Science Ningbo UniversityNingbo 315211China Faculty of Material Science and Chemical Engineering Ningbo UniversityNingbo 315211China Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices Ningbo Institute of Materials Technology&EngineeringChinese Academy of SciencesNingbo 315201China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049China Department of Chemical and Environmental Engineering University of Nottingham NingboNingbo 315100China

The micro-morphology and molecular stacking play a key role in determining the charge transport process and nonradiative energy loss, thus impacting the performances of organic solar cells(OSCs). To address this issue, a non-fullerene acceptor PhC6-IC-F with alkylbenzene side-chain, possessing optimized molecular stacking, complementary absorption spectra and forming a cascade energy level alignment in the PM6:BTP-eC9 blend, is introduced as guest acceptor to improve efficiency of ternary OSCs. The bulky phenyl in the side-chain can regulate crystallinity and optimizing phase separation between receptors in ternary blend films, resulting in the optimal phase separations in the ternary films. As a result, high efficiencies of 18.33% as photovoltaic layer are obtained for PhC6-IC-F-based ternary devices with excellent fill factor(FF) of 78.92%. Impressively, the ternary system produces a significantly improved open circuit voltage(V_(oc)) of 0.857 V compared with the binary device,contributing to the reduced density of trap states and suppressed non-radiative recombination result in lower energy loss. This work demonstrates an effective approach for adjusting the aggregation, molecular packing and fine phase separation morphology to increase V_(oc) and FF, paving the way toward high-efficiency OSCs.

关键词： alkylbenzene side-chain morphology regulation ternary blends organic solar cells

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Blood glucose-lowering activity of protocatechuic acid is mediated by inhibiting a-glucosidase

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Food Science and Human Wellness 2024年第3期13卷 1212-1219页

作者： Huafang Ding Shouhe Huang Chui Yiu Chook Erika Kwek Chi Yan Kaying Ma Jianhui Liu Hanyue zhu zhenyu Chen Food&Nutritional Sciences Programme School of Life SciencesThe Chinese University of Hong KongHong Kong 999077China

α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in various plant foods but also as a major microbial metabolite of dietary anthocyanins in the large colon.The present study investigated the inhibitory mechanism of PCA on a-glucosidase in vitro and examined its effect on postprandial blood glucose levels in vivo.Results from in vitro experiments demonstrated that PCA was a mix-type inhibitor of a-glucosidase.Driven by hydrogen bonds and van der Waals interactions,PCA reversibly bound withα-glucosidase to form a stable a-glucosidase-PCA complex in a spontaneous manner.The computational simulation found that PCA could insert into the active cavity of a-glucosidase and establish hydrogen bonds with catalytic amino acid residues.PCA binding aroused the steric hindrance for substrates to enter active sites and caused the structural changes of interacted catalytic amino acid residues.PCA also exhibited postprandial hypoglycemic capacity in diabetic mice.This study may provide the theoretical basis for the application of PCA as an active ingredient of functional foods in dietary management of diabetes.

关键词： Protocatechuic acid α-Glucosidase Postprandial hyperglycemia Inhibition mechanism

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Numerical Simulation of Low Cycle Fatigue Behavior of Ti_(2)AlNb Alloy Subcomponents

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Computer Modeling in Engineering & Sciences 2023年第9期136卷 2655-2676页

作者： Yanju Wang zhenyu zhu Aixue Sha Wenfeng Hao Materials Evaluation Center for Aeronautical and Aeroengine Application AECC Beijing Institute of Aeronautical MaterialsBeijing100095China Faculty of Civil Engineering and Mechanics Jiangsu UniversityZhenjiang212013China College of Mechanical Engineering Yangzhou UniversityYangzhou225127China

Many titanium alloy subcomponents are subjected to fatigue loading in aerospace engineering,resulting in fatigue failure.The fatigue behavior of Ti_(2)AlNb alloy subcomponents was investigated based on the Seeger fatigue life theory and the improved Lemaitre damage evolution theory.Firstly,the finite element models of the standard openhole specimen and Y-section subcomponents have been established by ABAQUS.The damage model parameters were determined by fatigue tests,and the reliability of fatigue life simulation results of the Ti_(2)AlNb alloy standard open-hole specimen was verified.Meanwhile,the fatigue life of Ti_(2)AlNb alloy Y-section subcomponents was predicted.Under the same initial conditions,the average error of fatigue life predicted by two different models was 20.6%.Finally,the effects of loading amplitude,temperature,and Y-interface angle on fatigue properties of Ti_(2)AlNb Y-section subcomponents were investigated.These results provide a new idea for evaluating the fatigue life of various Ti_(2)AlNb alloy subcomponents.

关键词： Fatigue life prediction stiffness degeneration Ti2AlNb alloy continuous damage mechanics numerical simulation

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High thermoelectric properties with low thermal conductivity due to the porous structure induced by the dendritic branching in n-type PbS

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Nano Research 2022年第5期15卷 4739-4746页

作者： zhenyu zhu Janak Tiwari Tianli Feng Zhan Shi Yue Lou Biao Xu School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China Department of Mechanical Engineering The University of UtahSalt Lake CityUT 84112USA State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210000China

PbS-based thermoelectric materials have attracted extensive attention in recent years for the advantages of earth abundancy and low cost,which is considered to be a substitute for traditional PbTe material.However,their high thermal conductivity restricts its development.Hence,in order to improve their thermoelectric performance from reducing the thermal conductivity,a kind of dendritic PbS with controlled crystal grain and morphology are obtained by solution synthesis.By adjusting the amount of surfactant(CTAB),the specific formation process of dendrites is regulated.After sintering,the dendritic PbS nanoparticles are easy to form porous structure due to the overlapping and staggered arrangement of dendritic branches.For comparison,we also prepare a kind of regular octahedral PbS and a dense packing arrangement is formed because of the integrity of the octahedral structure.DFT-based Boltzmann transport equation is used to prove the crucial role of porous structure in scattering phonon.Finally,a maximum zT=1.0 at 773 K in n-type PbS is obtained,which still keep a high-speed growth and is expected to get higher zT value in a higher temperature region.Our work may shed light to other thermoelectric materials from the formation of porous structure to reduce the thermal conductivity.

关键词： thermoelectric materials lead sulfide solution synthesis porous structure

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Temperature‑Arousing Self‑Powered Fire Warning E‑Textile Based on p-n Segment Coaxial Aerogel Fibers for Active Fire Protection in Firefighting Clothing

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Nano-Micro Letters 2023年第12期15卷 141-160页

作者： Hualing He Yi Qin zhenyu zhu Qing Jiang Shengnan Ouyang Yuhang Wan Xueru Qu Jie Xu Zhicai Yu State Key Laboratory of New Textile Materials and Advanced Processing Technologies School of Textile Science and EngineeringWuhan Textile UniversityWuhan 430200People’s Republic of China National Local Joint Laboratory for Advanced Textile Processing and Clean Production Hubei Key Laboratory of Biomass Fibers and Eco‑Dyeing and FinishingWuhan Textile UniversityWuhan 430200People’s Republic of China Jiangsu New Horizon Advanced Functional Fiber Innovation Center Co. Ltd.Suzhou 215000People’s Republic of China

Firefighting protective clothing is a crucial protective equipment for firefighters to minimize skin burn and ensure safety firefighting operation and rescue mission.A recent increasing concern is to develop self-powered fire warning materials that can be incorporated into the firefighting clothing to achieve active fire protection for firefighters before the protective clothing catches fire on fireground.However,it is still a challenge to facilely design and manufacture thermoelectric(TE)textile(TET)-based fire warning electronics with dynamic surface conformability and breathability.Here,we develop an alternate coaxial wet-spinning strategy to continuously produce alternating p/n-type TE aerogel fibers involving n-type Ti_(3)C_(2)T_(x)MXene and p-type MXene/SWCNT-COOH as core materials,and tough aramid nanofiber as protective shell,which simultaneously ensure the flexibility and high-efficiency TE power generation.With such alternating p/n-type TE fibers,TET-based self-powered fire warning sensors with high mechanical stability and wearability are successfully fabricated through stitching the alternating p-n segment TE fibers into aramid fabric.The results indicate that TET-based fire warning electronics containing 50 p-n pairs produce the open-circuit voltage of 7.5 mV with a power density of 119.79 nW cm-2 at a temperature difference of 300℃.The output voltage signal is then calculated as corresponding surface temperature of firefighting clothing based on a linear relationship between TE voltage and temperature.The fire alarm response time and flame-retardant properties are further displayed.Such self-powered fire warning electronics are true textiles that offer breathability and compatibility with body movement,demonstrating their potential application in firefighting clothing.

关键词： Self-powered fire warning Coaxial wet spinning P-n segment thermoelectric fiber Thermoelectric textiles Active fire protection

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