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Science China Chemistry 2022年第2期65卷 298-303页

作者： tian-ci Wang Pu-Sheng Wang Dian-Feng Chen Liu-Zhu Gong Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of ChinaHefei 230026China Center for Excellence in Molecular Synthesis of CAS Hefei 230026China

Chiral homoallylic vicinal diols are found in many bioactive compounds and are among the most versatile functional groups in organic chemistry. Here, we describe an asymmetric carbonyl allylation of aldehydes with allyl ethers proceeding via allylic C-H borylation enabled by palladium and chiral phosphoric acid sequential catalysis, providing facile access to homoallylic vicinal anti-diols in high yields and with excellent stereoselectivity. This protocol enables the total synthesis of aigialomycin D to be finished within 7 steps.

关键词： asymmetric catalysis palladium allylic C–H borylation allyl ethers chiral phosphoric acid aldehydes

Security in edge-assisted Internet of Things:challenges and solutions

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Science China(Information Sciences) 2020年第12期63卷 27-40页

作者： Shuaiqi SHEN Kuan zhang Yi ZHOU Song ci Department of Electrical and Computer Engineering University of Nebraska-Lincoln School of Computer and Information Engineering Henan University Department of Electrical Engineering Tsinghua University

The flourish of 5th generation wireless systems(5G) network has brought numerous benefits to the Internet of Things(IoT) with universal connectivity, improved data rate, and decreased latency. The development of IoT extends the computation-intensive applications from centralized servers to the edge of the network, promoting the paradigm of edge computing. Edge computing brings great assistance to IoT architecture by efficiently accomplishing tasks with lower latency, less energy consumption and reduced network bandwidth. Edge-assisted IoT emerges to provide location-aware services and offload computational tasks to edge nodes near the IoT devices. However, a series of security challenges still exist in edge-assisted IoT owing to the inherent vulnerabilities of edge nodes and sensitive nature of the collected data. Among the emerging and existing security schemes in IoT applications, security and energy consumption are two overriding yet conflicting requirements. The tradeoff between security and energy is critical to the sustainability of the IoT ecosystem but still lacks sufficient discussion. In this article, we investigate the security challenges in edge-assisted IoT and how the constraints in energy consumption can affect the design of security ***, we firstly present the architecture of edge-assisted IoT and its unique characteristics. Secondly,we identify the security threats in the edge-assisted IoT applications and the security-energy tradeoff during implementation. Thirdly, in a case study of distributed denial of service(DDoS) and malware injection attack, we propose a preliminary solution to address the conflict between security and energy ***, we discuss some open issues and identify future research directions for security and energy efficiency in edge-assisted IoT.

关键词： Internet of Things edge computing network security machine learning data analytics

Search for gamma-ray line signals around the black hole at the galactic center with DAMPE observation

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Science China(Physics,Mechanics & Astronomy) 2022年第6期65卷 150-158页

作者： tian-ci Liu Ji-Gui Cheng Yun-Feng Liang En-Wei Liang Laboratory for Relativistic Astrophysics Department of PhysicsGuangxi UniversityNanning 530004China

The adiabatic growth of a black hole(BH)may enhance the dark matter(DM)density surrounding it,causing a spike in the DM density *** spike around the supermassive BH at the center of the Milky Way may lead to a dramatic enhancement of the gamma-ray flux of DM annihilation from the galactic center(GC).In this work,we analyze the gamma-ray data of the innermost region(i.e.,the inner 1°)of the GC to search for potential line-like signals from the BH *** line-like signals could be generated in the process of DM particles annihilating into double *** adopt the gamma-ray data from the Dark Matter Particle Explorer(DAMPE).Although the DAMPE has a much smaller effective area than the Fermi-LAT,the gamma-ray line search can benefit from its unprecedented high energy *** significant line-like signals are found in our *** derive upper limits on the cross section of the annihilation based on this *** find that despite the DAMPE’s small effective area for photon detection,we can still place strong constraints on the cross section(≥10^(-27)cm^(3)s^(-1))in the spike scenario due to the very bright model-expected flux from the *** results indicate that either DM does not annihilate primarily through theγγchannel in the mass range we considered or no sharp density spike is present at the GC.

关键词： dark matter γ-ray telescopes black holes galactic center

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Thermal-flow-electric coupling performance analysis of a liquid-immersed battery thermal management system

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Science China Technological Sciences 2025年第1期 157-176页

作者： Qiang GAO Jun tian Chujin BAO Yangfan ZHONG Chengbin zhang Yongping CHEN School of Energy and Environment Southeast University Battery Testing Center China North Vehicle Research Institute Zhejiang Immertech Co. Ltd. Alibaba Cloud Computing Co. Ltd.

Ensuring the safety and performance of lithium-ion batteries(LIBs) is a significant challenge for electric *** tackle this issue, an innovative liquid-immersed battery thermal management system(LIBTMS) using bionic baffles with fish-like perforations is developed. The thermal-flow-electric coupling characteristics of LIBTMSs with different baffle structures(no baffle, conventional baffle, baffle with circular perforations and baffle with fish-like perforations) are systematically investigated using experimental and numerical methods. The results indicate that the forced flow scheme exhibits better thermal management performance and voltage equalization than static flow. Moreover, the LIB temperatures and voltage deviations of different LIBTMSs increase quickly with increasing discharge rates. More importantly, the innovative LIBTMS exhibits the best thermoelectric performance due to its excellent thermoelectric equilibrium behavior caused by high electrical and temperature consistency, as well as the best overall performance involving the balance between the pressure loss and heat transfer capacity of the system. Compared with other structures, the innovative LIBTMS using baffles with fish-like perforations exhibits a maximum reduction of 10.1%, 15.2%, 25.8% and 9.0% in LIB maximum temperature, maximum temperature difference, system pressure drop and voltage deviation, respectively, under the same operating ***, for the LIBTMS using baffles with fish-like perforations, the bottom inlet and top outlet configuration and coolant precooling are suggested to enhance cooling performance.

关键词：

A novel active-passive protection strategy endows carbonyl iron with excellent intelligent anti-corrosion and microwave absorption dual functional characteristics

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Nano Research 2025年第1期18卷 487-500页

作者： Wei tian Quanyuan Feng Linbo zhang Yinfan Liu Xian Jian Longjiang Deng Institute of Microelectronics School of Information Science and TechnologySouthwest Jiaotong UniversityChengdu 611756China National Engineering Researching Centre of Electromagnetic Radiation Control Materials Key Laboratory of Multi-Spectral Absorbing Materials and Structures of Ministry of EducationState Key Laboratory of Electronic Thin Films and Integrated DevicesSchool of Electronic Science and EngineeringUniversity of Electronic Science and Technology of ChinaChengdu 611731China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China The Yangtze Delta Region Institute(Huzhou)&School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaHuzhou 313001China

Carbonyl iron absorbers(ci)face significant challenges in practical applications,such as corrosion,interface bonding failure,detachment,and high maintenance ***,we have developed intelligent self-healing technology based on proactive/passive mechanisms via in situ synthesis of self-healing factors(polydopamine/benzotriazole(PDA/BTA))and physical barrier layers(SiO_(2)/1,1,1,3,3,3-hexamethyl disilazane,SiO_(2)/HMDS)to enhance corrosion resistance,while also being compatible with efficient microwave absorption *** unique multiscale structure gives full play to the utilization of the roles of each functional layer,including the intelligent self-healing features of PDA/BTA,physical shielding and spatial confinement characteristics of SiO_(2)/HMDS,and magnetic-dielectric synergistic mechanism resulted from the good impedance matching characteristics,the conduction loss,the interfacial polarization loss and natural *** asfabricated composites achieved an exceptional minimum reflection loss value of-55.4 dB at 10.7 GHz and the effective absorption band of 7.6 ***,it still exhibits obvious self-healing and corrosion resistance characteristics after 360 h corrosion treatment,ascribed to the self-healing mechanism of PDA/BTA and the blocking intervention effect of SiO_(2)/*** work is considered to pave the way for the synthesis of high-performance magnetic absorbers,especially in enhancing their intelligent self-healing ability in corrosive environments.

关键词： microwave absorption intelligent self-healing technology carbonyl iron multiscale structure magneticdielectric synergistic mechanism

The wheat receptor-like cytoplasmic kinase TaRLCK1B is required for host immune response to the necrotrophic pathogen Rhizoctonia cerealis

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Journal of Integrative Agriculture 2020年第11期19卷 2616-2627页

作者： WU tian-ci ZHU Xiu-liang LÜLiang-jie CHEN Xi-yong XU Gang-biao zhang Zeng-yan Laboratory of Forestry Genetics Central South University of Forestry and TechnologyChangsha 410004P.R.China National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences Chinese Academy of Agricultural SciencesBeijing 100081P.R.China Institute for Cereal and Oil Crops Hebei Academy of Agriculture and Forestry SciencesShijiazhuang 050035P.R.China

Receptor-like cytoplasmic kinases(RLCKs)represent a large family of proteins in *** Arabidopsis and rice,several RLCKs in subfamily VII(RLCKs-VII)have been implicated in pathogen-associated molecular pattern-triggered immunity and basal resistance against bacterial and fungal ***,little is known about roles of RLCKs-VII of the important crop common wheat(Triticum aestivum)in immune ***,we isolated a RLCK-VII-encoding gene from wheat,designated as TaRLCK1B,and investigated its role in host immune response to infection of a necrotrophic fungus Rhizoctonia cerealis that is a major pathogen of sharp eyespot,a destructive disease of ***-sequencing and RT-qPCR analyses showed that transcriptional level of TaRLCK1B was significantly higher in sharp eyespot-resistant wheat cultivars than in susceptible wheat *** gene transcription was rapidly and markedly elevated in the resistant wheat cultivars by *** *** TaRLCK1B protein was closely related to OsRLCK176,a rice resistance-related RLCKs-VII,with 84.03%***-induced gene silencing plus wheat response to *** assay results indicated that silencing of TaRLCK1 impaired resistance to ***,silencing of TaRLCK1 significantly elevated both the content of H2 O2(a major kind of reactive oxygen species,ROS)and the transcriptional level of the ROS-generating enzyme-encoding gene RBOH,but repressed the expression of the ROS-scavenging enzyme-encoding gene CAT1 at 18 hours after inoculation(hai)with *** together,these data suggested that TaRLCK1B was required for the early immune response of wheat to *** through modulating ROS signaling in wheat.

关键词： common wheat(Triticum aestivum) H2 O2 immune response reactive oxygen species receptor-like cytoplasmic kinase Rhizoctonia cerealis

Mercury in leaf litter in typical suburban and urban broadleaf forests in China

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Journal of Environmental Sciences 2011年第12期23卷 2042-2048页

作者： Zhenchuan Niu Xiaoshan zhang zhangwei Wang Zhijia ci Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

To study the role of leaf litter in the mercury （Hg） cycle in suburban broadleaf forests and the distribution of Hg in urban forests, we collected leaf litter and soil from suburban evergreen and deciduous broadleaf forests and from urban forests in Beijing. The Hg concentrations in leaf litter from the suburban forests varied from 8.3 to 205.0 ng/g, with an average （avg） of （49.7 ± 36.9） ng/g. The average Hg concentration in evergreen broadleaf forest leaf litter （50.8 ± 39.4） ng/g was higher than that in deciduous broadleaf forest leaf litter （25.8 ± 10.1） ng/g. The estimated Hg fluxes of leaf litter in suburban evergreen and deciduous broadleaf forests were 179.0 and 83.7 mg/（ha·yr）, respectively. The Hg concentration in organic horizons （O horizons）（（263.1 ± 237.2） ng/g） was higher than that in eluvial horizons （A horizons）（（83.9 ± 52.0） ng/g）. These results indicated that leaf litterfall plays an important role in transporting atmospheric mercury to soil in suburban forests. For urban forests in Beijing, the Hg concentrations in leaf litter ranged from 8.8–119.0 （avg 28.1 ± 16.6） ng/g, with higher concentrations at urban sites than at suburban sites for each tree. The Hg concentrations in surface soil in Beijing were 32.0–25300.0 ng/g and increased from suburban sites to urban sites, with the highest value from Jingshan （JS） Park at the centre of Beijing. Therefore, the distribution of Hg in Beijing urban forests appeared to be strongly influenced by anthropogenic activities.

关键词： mercury broadleaf forests leaf litter soil flux

Robust adaptive radar beamforming based on iterative training sample selection using kurtosis of generalized inner product statistics

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Journal of Systems Engineering and Electronics 2024年第1期35卷 24-30页

作者： tian Jing zhang Wei School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Electromagnetic Space Security Chengdu 610036China

In engineering application,there is only one adaptive weights estimated by most of traditional early warning radars for adaptive interference suppression in a pulse reputation interval(PRI).Therefore,if the training samples used to calculate the weight vector does not contain the jamming,then the jamming cannot be removed by adaptive spatial *** the weight vector is constantly updated in the range dimension,the training data may contain target echo signals,resulting in signal cancellation *** cope with the situation that the training samples are contaminated by target signal,an iterative training sample selection method based on non-homogeneous detector(NHD)is proposed in this paper for updating the weight vector in entire range *** principle is presented,and the validity is proven by simulation results.

关键词： adaptive radar beamforming training sample selection non-homogeneous detector electronic jamming jamming suppression

Dominant role of in situ native cartilage niche for determining the cartilage type regenerated by BMSCs

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Bioactive Materials 2022年第7期7卷 149-160页

作者： Mengjie Hou Baoxing tian Baoshuai Bai Zheng ci Yu Liu Yixin zhang Guangdong Zhou Yilin Cao Department of Plastic and Reconstructive Surgery Shanghai 9th People’s HospitalShanghai Jiao Tong University School of MedicineShanghai Key Laboratory of Tissue EngineeringShanghaiPR China National Tissue Engineering Center of China ShanghaiPR China Research Institute of Plastic Surgery Wei Fang Medical CollegeWeifangPR China Department of Breast Surgery Tongren HospitalShanghai Jiao Tong University School of MedicineShanghai200336PR China

Tissue-engineered cartilage regeneration by bone marrow stromal cells(BMSCs)is considered an ideal ***,how to regulate BMSCs to regenerate specific types of cartilage remains unclear,which significantly limits its clinical translation and leads to suboptimal clinical ***,we systematically explored the role of native ear and articular cartilage niches on the differentiation fate of BMSCs and the type of regenerated ***,we prepared two types of acellular cartilage sheets(ACSs)and two types of *** green fluorescent protein-labeled BMSCs were seeded on two types of ACSs with or without corresponding types of chondrocytes using a sandwich model and directed or cross-implanted them into native cartilage *** one year of in vivo culture,cell tracking and the results of histological results showed that the native cartilage niches were capable of regulating BMSCs regeneration into specific types of cartilage that were consistent with the cartilage types of the implanted ***,even when the type of niche formed by ACSs or the biomimetic cartilage niche constructed by specific types of ACSs and specific types of chondrocytes did not match with the native cartilage niche,the native cartilage niche continued to determine the type of cartilage regenerated by implanted BMSCs and *** our results provide sufficient evidence for specific types of cartilage regeneration using chondrogenic potential cells,such as mesenchymal stem cells and chondrocytes.

关键词： BMSCs Niche Cartilage type Cartilage regeneration In situ Chondrocytes

Predicting Hyper-Chaotic Time Series Using Adaptive Higher-Order Nonlinear Filter

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Chinese Physics Letters 2001年第3期18卷 337-340页

作者： zhang Jia-Shu XIAO Xian-ci Department of Electronic Engineering University of Electronic Science and Technology of ChinaChengdu 610054

A newly proposed method,*** adaptive higher-order nonlinear finite impulse response(HONFIR)filter based on higher-order sparse Volterra series expansions,is introduced to predict hyper-chaotic time *** effectiveness of using adaptive HONFIR filter for making one-step and multi-step predictions is tested based on very few data points by computer-generated hyper-chaotic time series including Mackey-Glass equation and 4-dimensional nonlinear dynamical system.A comparison is made with some neural networks for predicting the Mackey-Glass hyper-chaotic time *** simulation results show that the adaptive HONFIR filter proposed here is a very powerful tool for making prediction of hyper-chaotic time series.

关键词： chaotic nonlinear Nonlinear