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Tungsten 2024年第1期6卷 134-140页

作者： Lin-Chao Zhang Ke Jing Rui Liu Zhuo-Ming xie Jun-Feng Yang Gang Li Xian-ping Wang Xue-Bang Wu Qian-Feng Fang Chang-Song Liu Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610041China

The cermet fuels have been considered as a potential key component for the nuclear thermal propulsion,and the homogeneity of the fuel particles in the metal matrix plays a crucial role in stabilizing the structure at extremely high *** this work,liquid paraffin was used as additive to improve the distribution of yttria-stabilized zirconia(YSZ,an appropriate surrogate for UO_(2) fuel)microspheres in the tungsten(W)matrix,and the W-YSZ cermet wafers(volume ratio 1:1)with a relative density of 97.6%were fabricated by spark plasma sintering with a specifically designed *** effects of the paraffin dosage(0-5 wt.%)on the homogeneity,microstructure,mechanical properties,and the thermal conductivity of W-YSZ cermet were *** W-YSZ sample with 2 wt.%paraffin shows the highest homogeneity and exhibits the best comprehensive properties,including the ultimate tensile strength of 132.2 MPa at 600℃,the bending strength of455 MPa and thermal conductivity of 50 W·m^(-1)·K^(-1)at room ***,the cermet could keep structurally sound after thermal shocked at a heat load of 20 MW·m^(-2).These results would be helpful for the design and optimization of the cermet fuels in the nuclear thermal propulsion.

关键词： Nuclear thermal propulsion Tungsten Cermet Liquid paraffin Thermal shock

Visible-Light-Promoted Palladium-Catalyzed Cross-Coupling of lodocarboranes with Disulfides and Phenylselenyl Chloride

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Chinese Journal of Chemistry 2024年第2期42卷 129-134页

作者： Shimeng Li Yizhen Liu Zuowei xie Shenzhen Grubbs Institute and Department of Chemistry Southern University of Science and TechnologyShenzhenGuangdong 518055China

This work describes a general method for the synthesis of a series of sulfenylated and selenylated carboranes at room temperature using readily available iodocarboranes as starting materials via boron-centered carboranyl *** hypervalent boron radicals are generated by a visible-light-promoted Pd(O)/Pd(I)*** are useful intermediates and can be trapped by disulfides and phenylselenyl chloride for the convenient construction of B-S/Sebonds.

关键词： Carborane Sulfenylation Selenylation B-I activation Radical Photocatalysis Boron Selectivity

Spatio-temporal variability of surface chlorophyll a in the Yellow Sea and the East China Sea based on reconstructions of satellite data of 2001-2020

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Journal of Oceanology and Limnology 2024年第2期42卷 390-407页

作者： Weichen xie Tao WANG Wensheng JIANG Key Laboratory of Marine Environment and Ecology Ocean University of ChinaQingdao 266100China College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266100China

Chlorophyll-a(Chl-a)concentration is a primary indicator for marine environmental *** spatio-temporal variations of sea surface Chl-a concentration in the Yellow Sea(YS)and the East China Sea(ECS)in 2001-2020 were investigated by reconstructing the MODIS Level 3 products with the data interpolation empirical orthogonal function(DINEOF)*** reconstructed results by interpolating the combined MODIS daily+8-day datasets were found better than those merely by interpolating daily or 8-day ***-a concentration in the YS and the ECS reached its maximum in spring,with blooms occurring,decreased in summer and autumn,and increased in late autumn and early *** performing empirical orthogonal function(EOF)decomposition of the reconstructed data fields and correlation analysis with several potential environmental factors,we found that the sea surface temperature(SST)plays a significant role in the seasonal variation of Chl a,especially during spring and *** increase of SST in spring and the upper-layer nutrients mixed up during the last winter might favor the occurrence of spring *** high sea surface temperature(SST)throughout the summer would strengthen the vertical stratification and prevent nutrients supply from deep water,resulting in low surface Chl-a *** sea surface Chl-a concentration in the YS was found decreased significantly from 2012 to 2020,which was possibly related to the Pacific Decadal Oscillation(PDO).

关键词： chlorophyll a(Chl a) data interpolation empirical orthogonal function(DINEOF) empirical orthogonal function(EOF)analysis Yellow Sea East China Sea

Mega-Constellations Based TT&C Resource Sharing: Keep Reliable Aeronautical Communication in an Emergency

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China Communications 2024年第2期21卷 1-16页

作者： Haoran xie Yafeng Zhan Jianhua Lu Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

With the development of the transportation industry, the effective guidance of aircraft in an emergency to prevent catastrophic accidents remains one of the top safety concerns. Undoubtedly, operational status data of the aircraft play an important role in the judgment and command of the Operational Control Center(OCC). However, how to transmit various operational status data from abnormal aircraft back to the OCC in an emergency is still an open problem. In this paper, we propose a novel Telemetry, Tracking,and Command(TT&C) architecture named Collaborative TT&C(CoTT&C) based on mega-constellation to solve such a problem. CoTT&C allows each satellite to help the abnormal aircraft by sharing TT&C resources when needed, realizing real-time and reliable aeronautical communication in an emergency. Specifically, we design a dynamic resource sharing mechanism for CoTT&C and model the mechanism as a single-leader-multi-follower Stackelberg game. Further, we give an unique Nash Equilibrium(NE) of the game as a closed form. Simulation results demonstrate that the proposed resource sharing mechanism is effective, incentive compatible, fair, and reciprocal. We hope that our findings can shed some light for future research on aeronautical communications in an emergency.

关键词： aeronautical emergency communication mega-constellation networked TT&C resource allocation stackelberg game

Observer design and interval estimation of time-delay discrete-time linear systems with external disturbance and measurement noise

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Control Theory and Technology 2024年第1期22卷 69-80页

作者： Junqi Yang Jianhao xie Feiyang Liu School of Electrical Engineering and Automation Henan Key Laboratory of Intelligent Detection and Control of Coal Mine EquipmentHenan Polytechnic UniversityJiaozuo454003HenanChina

For a class of time-delay discrete-time linear systems with external disturbance and measurement noise, the interval estimation problems of state and measurement noise are investigated in this paper. First, the system state together with the time-delay term and measurement noise is augmented as a new state, and a singular system is then constructed. Subsequently, a kind of decoupling technique is employed to eliminate the effect of external disturbance, and an observer is designed to simultaneously estimate the system state and measurement noise. Based on the estimated state and measurement noise, the interval estimations of system state and measurement noise are obtained by reachability analysis technique. Finally, the effectiveness of the proposed method is verified by a four-tank liquid level system.

关键词： Interval estimation Time-delay system Observer design Reachability analysis

A human-specific insertion promotes cell proliferation and migration by enhancing TBC1D8B expression

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Science China(Life Sciences) 2024年第4期67卷 765-777页

作者： Hui Zhao Lin-Lin Liu Jian Sun Lian Jin hai-Bing xie Jian-Bo Li Hui Xu Dong-Dong Wu Xiao-Lin Zhuang Min-Sheng Peng Ya-Jun Guo Wei-Zhu Qian Newton OOtecko Wei-Jie Sun Liang-Hu Qu Jie He Zhao-Li Chen Rong Liu Ce-Shi Chen Ya-ping Zhang State Key Laboratory for Conservation and Utilization of Bio-resource School of Life SciencesSchool of Ecology and Environmental ScienceYunnan UniversityKunming 650091China School of Forensic Medicine Kunming Medical UniversityKunming 650500China Academy of Biomedical Engineering Kunming Medical UniversityKunming 650500China The Third Affiliated Hospital Kunming Medical UniversityKunming 650118China Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province Kunming Institute of ZoologyChinese Academy of SciencesKunming 650201China State Key Laboratory of Genetic Resources and Evolution Yunnan Laboratory of Molecular Biology of Domestic AnimalsKunming Institute of ZoologyChinese Academy of SciencesKunming 650201China The Key Laboratory of Gene Engineering of the Ministry of Education State Key Laboratory for BiocontrolSun Yat-sen UniversityGuangzhou 510275China National Engineering Research Center for Antibody Medicine and Shanghai Key Laboratory of Cell Engineering and Antibody Shanghai 201203China Department of Thoracic Surgery Cancer Institute and HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100730China

Human-specific insertions play important roles in human phenotypes and *** we reported a 446-bp insertion(Insert-446)in intron 11 of the TBC1D8B gene,located on chromosome X,and traced its origin to a portion of intron 6 of the EBF1 gene on chromosome ***,Insert-446 was present in the human Neanderthal and Denisovans genomes,and was fixed in humans after human-chimpanzee *** have demonstrated that Insert-446 acts as an enhancer through binding transcript factors that promotes a higher expression of human TBC1D8B gene as compared with orthologs in *** addition,over-expression TBC1D8B promoted cell proliferation and migration through“a dual finger”catalytic mechanism(Arg538 and Gln573)in the TBC domain in vitro and knockdown of TBC1D8B attenuated tumorigenesis in *** of Insert-446 prevented cell proliferation and migration in cancer and normal *** results reveal that the human-specific Insert-446 promotes cell proliferation and migration by upregulating the expression of TBC1D8B *** findings provide a significant insight into the effects of human-specific insertions on evolution.

关键词： human-specific insertion enhancer gene expression cell proliferation and migration

NONMONOTONE LOCAL MINIMAX METHODS FOR FINDING MULTIPLE SADDLE POINTS

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Journal of Computational Mathematics 2024年第3期42卷 851-884页

作者： Wei Liu Ziqing xie Wenfan Yi South China Research Center for Applied Mathematics and Interdisciplinary Studies South China Normal UniversityGuangzhou 510631China Key Laboratory of Computing and Stochastic Mathematics(Ministry of Education) Hunan Normal UniversityChangshaHunan 410081China Hunan Provincial Key Laboratory of Intelligent Information Processing and Applied Mathematics School of MathematicsHunan UniversityChangshaHunan 410082China

In this paper,by designing a normalized nonmonotone search strategy with the BarzilaiBorwein-type step-size,a novel local minimax method(LMM),which is a globally convergent iterative method,is proposed and analyzed to find multiple(unstable)saddle points of nonconvex functionals in Hilbert *** to traditional LMMs with monotone search strategies,this approach,which does not require strict decrease of the objective functional value at each iterative step,is observed to converge faster with less ***,based on a normalized iterative scheme coupled with a local peak selection that pulls the iterative point back onto the solution submanifold,by generalizing the Zhang-Hager(ZH)search strategy in the optimization theory to the LMM framework,a kind of normalized ZH-type nonmonotone step-size search strategy is introduced,and then a novel nonmonotone LMM is *** feasibility and global convergence results are rigorously carried out under the relaxation of the monotonicity for the functional at the iterative ***,in order to speed up the convergence of the nonmonotone LMM,a globally convergent Barzilai-Borwein-type LMM(GBBLMM)is presented by explicitly constructing the Barzilai-Borwein-type step-size as a trial step-size of the normalized ZH-type nonmonotone step-size search strategy in each ***,the GBBLMM algorithm is implemented to find multiple unstable solutions of two classes of semilinear elliptic boundary value problems with variational structures:one is the semilinear elliptic equations with the homogeneous Dirichlet boundary condition and another is the linear elliptic equations with semilinear Neumann boundary *** numerical results indicate that our approach is very effective and speeds up the LMMs significantly.

关键词： Multiple saddle points Local minimax method Barzilai-Borwein gradient method Normalized nonmonotone search strategy Global convergence

Why Are Arctic Sea Ice Concentration in September and Its Interannual Variability Well Predicted over the Barents–East Siberian Seas by CFSv2?

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Journal of Meteorological Research 2024年第1期38卷 53-68页

作者： Yifan xie Ke FAN Hongqing YANG School of Atmospheric Sciences Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082

To further understand the prediction skill for the interannual variability of the sea ice concentration(SIC)in specific regions of the Arctic,this paper evaluates the NCEP Climate Forecast System version 2(CFSv2),in predicting the autumn SIC and its interannual variability over the Barents–East Siberian Seas(BES).It is found that CFSv2 presents much better prediction skill for the September SIC over BES than the Arctic as a whole at 1–6-month leads,and high prediction skill for the interannual variability of the SIC over BES is displayed at 1–2-month leads after removing the linear ***2 can reasonably reproduce the relationship between the SIC over BES in September and such factors as the surface air temperature(SAT),200-hPa geopotential height,sea surface temperature(SST),and North Atlantic *** addition,it is found that the prescribed SIC initial condition in August as an input to CFSv2 is also ***,the above atmospheric and oceanic factors,as well as an accurate initial condition of SIC,all contribute to a high prediction skill for SIC over BES in *** on a statistical prediction method,the contributions from individual predictability sources are further *** high prediction skill of CFSv2 for the interannual variability of SIC over BES is largely attributable to its accurate predictions of the SAT and SST,as well as a better initial condition of SIC.

关键词： sea ice concentration the Barents-East Siberian Seas Climate Forecast System version 2(CFSv2) prediction skill predictability source atmospheric and oceanic factors initial condition

“Steric Armor”Strategy of Blue Fluorescent Emitters against Photooxidation-Induced Degradation

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Chinese Journal of Chemistry 2024年第11期42卷 1223-1229页

作者： Sha-Sha Wang Jing-Rui Zhang Kuan-De Wang Hao-Ran Li Peng-Hui Meng Yang Zhou Xiang Yu Ying Wei Quan-You Feng Yu-He Kan Ling-hai xie Centre for Molecular Systems and Organic Devices(CMSOD) State Key Laboratory of Organic Electronics and Information Displays&Institute of Advanced MaterialsJiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)Nanjing University of Posts&TelecommunicationsNanjingJiangsu210023 China Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials School of Chemistry and Chemical EngineeringHuaiyin Normal UniversityHuai'anJiangsu223300 China

Stability against oxygen is an important factor affecting the performance of organic semiconductor *** photooxidation stability can prolong the service life of the device and maintain the mechanical and photoelectric properties of the ***,various encapsulation methods from molecular structure to macroscopic device level are used to improve photooxidation ***,we adopted a crystallization strategy to allow 14H-spiro[dibenzo[c,h]acridine-7,9′-fluorene](SFDBA)to pack tightly to resist fluorescence decay caused by *** this case,the inert group of SFDBA acts as a“steric armor”,protecting the photosensitive group from being attacked by ***,compared with the fluorescence quenching of SFDBA powder under 2 h of sunlight,SFDBA crystal can maintain its fluorescence emission for more than 8 h under the same ***,the photoluminescence quantum yields(PLQYs)of the crystalline film is 327%higher than that of the amorphous *** shows that the crystallization strategy is an effective method to resist oxidation.

关键词： Organic semiconductor Photooxidation Spirocyclic aromatic hydrocarbons Crystal engineering Fluorescence

One more step to realistic CO_(2) reduction reactions——geometric structures evolutions at gas-solid interface

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Rare Metals 2024年第2期43卷 849-852页

作者： Ya-Qiang xie Xin Yu Ting Wang College of the Environment and Ecology Xiamen UniversityXiamen361102China

A rational design of copper(Cu)nanocatalyst is critical to the efficient carbon dioxide(CO_(2))conversion toward C1/C2 chemical ***,the lack of actual information on the vicinal Cu interfaces hinders the intrinsic activitystructure correlation *** with atomic-scale in situ characterizations(AP-STM and synchrotron-based AP-XPS),Park and co-workers study and identify the adsorbate-driven morphological evolution of Cu nanoclusters on the Cu(997)surface,providing real-space evidence for the critical role of vicinal structures on Cu *** observed surface roughening trends caused by dissociated atomic oxygen and CO adsorbates subsequently affect the result of successive catalytic reactions to produce critical intermediates,such as carbonate and formate,during the CO_(2)reduction reaction.

关键词： reaction critical rational