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Transport induced dimer state from topological corner states

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Science China(Physics,Mechanics & Astronomy) 2021年第5期64卷 91-96页

作者： kai-Tong wang Yafei Ren Fuming Xu Yadong Wei Jian wang College of Physics and Energy Shenzhen UniversityShenzhen 518060China Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Opioelectronic Engineering.Shenzhen UniversiryShenzhen 518060China Department of Physics The University of Texas at AustinAustinTexas 78712USA College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Deparment of Physics University of Hong KongHong KongChina

Recently, a new type of second-order topological insulator has been theoretically proposed by introducing an in-plane Zeeman field into the Kane-Mele model in the two-dimensional honeycomb lattice. A pair of topological corner states arise at the corners with obtuse angles of an isolated diamond-shaped flake. To probe the corner states, we study their transport properties by attaching two leads to the system. Dressed by incoming electrons, the dynamic corner state is very different from its static *** tunneling through the dressed corner state can occur by tuning the in-plane Zeeman field. At the resonance, the pair of spatially well separated and highly localized corner states can form a dimer state, whose wavefunction extends almost the entire bulk of the diamond-shaped flake. By varying the Zeeman field strength, multiple resonant tunneling events are mediated by the same dimer state. This re-entrance effect can be understood by a simple model. These findings extend our understanding of dynamic aspects of the second-order topological corner states.

关键词： higher-order topological insulators multiple resonant tunneling in-plane Zeeman field two-dimensional honeycomb lattice

Who should be screened for colorectal cancer and how can it be prevented more effectively?

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World Journal of Gastrointestinal Oncology 2024年第9期16卷 3741-3746页

作者： You-Xiang wang kai-Juan wang College of Public Health Zhengzhou UniversityZhengzhou 450001Henan ProvinceChina College of Public Health Key Laboratory of Tumor Epidemiology of Henan ProvinceState Key Laboratory of Esophageal Cancer Prevention&TreatmentZhengzhou UniversityZhengzhou 450001Henan ProvinceChina

In this editorial,we comment on the article published by Agatsuma et al in a recent issue of the World J Gastroenterol(2024;30:1368-1376).We firmly concur with Agatsuma et al regarding the vital significance of colorectal cancer(CRC)screening as a public health strategy to diminish disease *** exposed to risk factors for CRC,those with comorbid conditions,and those with limited health literacy should undergo ***,we believe that more regular screenings should be accompanied by a greater focus on primary prevention(PP)of *** remains a significant global health challenge,and its incidence is strongly linked to age,lifestyle,and socioeconomic *** is particularly noteworthy that the majority of CRC patients are diagnosed outside of established screening pathways and frequently at an advanced stage of the disease,and the majority of patients possess inadequate or even nonexistent knowledge regarding CRC,which significantly impacts the prognosis and imposes a substantial economic *** study revealed that CRC identified during hospital visits for comorbid conditions was typically diagnosed at an earlier stage than detected via symptomatic ***,early incidental detection of CRC aligns closely with the timing of discovery through routine cancer *** suggests that by adopting more inclusive screening protocols that combine opportunistic testing with traditional screening methods,health care systems can create a more comprehensive safety net for individuals at risk of ***,before maximizing the health benefits of screening programs,it is essential to make additional efforts prior to screening,such as raising awareness via public education,risk assessment,and personalized recommendations,enhancing the knowledge and skills of health care professionals,optimizing the accessibility and convenience of screening processes,ensuring the quality and safety of screening services,strengthening follow-up and su

关键词： Colorectal cancer Primary prevention Screening program Disease burden Health literacy Economic benefits

Maximum Probabilistic and Dynamic Traffic Load Effects onShort-to-Medium Span Bridges

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Computer Modeling in Engineering & Sciences 2021年第4期127卷 345-360页

作者： Naiwei Lu Honghao wang kai wang Yang Liu School of Civil Engineering Changsha University of Science and TechnologyChangsha410114China School of Civil Engineering Hunan University of TechnologyZhuzhou412007China

The steadily growing traffic load has resulted in lots of bridge collapse events over the past decades, especiallyfor short-to-medium span bridges. This study investigated probabilistic and dynamic traffic load effects on shortto-medium span bridges using practical heavy traffic data in China. Mathematical formulations for traffic-bridgecoupled vibration and probabilistic extrapolation were derived. A framework for extrapolating probabilistic anddynamic traffic load effect was presented to conduct an efficient and accurate extrapolation. An equivalent dynamicwheel load model was demonstrated to be feasible for short-to-medium span bridges. Numerical studies of twotypes of simply-supported bridges were conducted based on site-specific traffic monitoring data. Numerical resultsshow that the simulated samples and fitting lines follow a curve line in the Gumbel distribution coordinate system. Itcan be assumed that dynamic traffic load effects follow Gaussian distribution and the extreme value follows Gumbeldistribution. The equivalent probabilistic amplification factor is smaller than the individual dynamic amplificationfactor, which might be due to the variability of individual samples. Eurocode 1 is the most conservative specificationon vehicle load models, followed by the BS5400 specification. The D60-2015 specification in China and ASSHTOspecification provide lower conservative traffic load models.

关键词： Bridge engineering vehicle load extreme value extrapolation stochastic traffic flow

Forest plant and macrofungal differences in the Greater and Lesser Khingan Mountains in Northeast China:A regional-historical comparison and its implications

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Journal of Forestry Research 2022年第2期33卷 623-641页

作者： Yuanyuan wang Hui Wen kai wang Jingxue Sun Jinghua Yu Qinggui wang Wenjie wang Key Laboratory of Forest Plant Ecology(MOE) College of ChemistryChemical Engineering and Resource UtilizationNortheast Forestry UniversityHarbin 150040People’s Republic of China Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102People’s Republic of China Institute of Applied Ecology Chinese Academy of SciencesShenyang 110016People’s Republic of China Department of Agricultural Resources and Environment Heilongjiang UniversityHarbin 150080People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China

Forests in Northeast China in the Greater and Lesser Khingan Mountains(GKM and LKM)account for nearly 1/3 of the total state-owned forests in the *** and historical comparisons of forest plants and macrofungi will favor biological conservation,forest management and economic development.A total of 1067 sampling plots were surveyed on forest composition and structure,with a macrofungi survey at Liangshui and Huzhong Nature Reserves in the center of two *** and historical differences of these parameters were analyzed with a redundancy ordination of their complex *** were 61-76 families,189-196 genera,and 369-384 species,which was only 1/3 of the historical *** same dominant species were larch and birch with Korean pine(a climax species)less as expected from past surveys in the *** and herb species were different in the two regions,as expected from historical *** was 10-50%lower species diversity(except for herb evenness),but 1.8-to 4-time higher macrofungi diversity in the *** with the LKM,both tree heights and macrofungi density were ***,current heights averaging 10 m are half of historical records(>20 m in the 1960s).Edible macrofungi were the highest proportion in both regions,about twice that of other fungal groups,hav-ing important roles in the local economy.A major factor explaining plant diversity variations in both regions was herb cover,followed by shrubs in the GKM and herb-dominant species in the *** responsible for macrofungi variations were tree density and shrub *** vitis-idaea and Larix gmelinii in the GKM but tree size and diversity were important factors in the *** findings highlighted large spatial and historical differences between the GKM and LKM in plant-macrofungal composition,forest structure,and their complex associations,which will favor precise conservation and management of forest resources in two region in the future.

关键词： Forest structure Biodiversity Redundancy ordination Species dominance Structure-species-diversity complex association decoupling

Deployment simulation of cable-strut structures considering cable sliding

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Science China(Technological Sciences) 2012年第12期55卷 3263-3269页

作者： CAI JianGuo FENG Jian wang kai Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education Southeast UniversityNanjing 210096China National Engineering Research Center for Prestress Southeast UniversityNanjing 210096China

The influence of cable sliding on the deployment of foldable cable-strut structures was studied in this paper. In order to develop an effective program for the cable sliding program, two-node cable element based on the analytical solution of elastic cate- nary was studied. Then the cable sliding stiffness was defined as the ratio of the variation of the cable force to the variation of the cable length. To validate the proposed numerical method, analyses of two examples given in references were carried out. The results show that the method given in this paper is accurate and effective, which can be used to model the cable sliding in cable structures. Finally, the deployment process of a foldable cable-strut structure, which is composed of four-bar linkages and cables, was discussed. It can be found that the effect of cable sliding on the behavior of cable-strut structures is significant. The length changes of active cables are smaller when the cable sliding is considered. Moreover, the nodal coordinate changes also become faster when the numerical model is with cable sliding.

关键词： deployment elastic catenary cable-strut structures cable sliding nonlinear analysis

Experiment and Simulation for Rolling of Diamond–Cu Composites

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Acta Metallurgica Sinica(English Letters) 2017年第8期30卷 791-800页

作者： Yun-Long wang kai-Kun wang Yu-Wei wang Guang-Chen Li School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Department of Engineering University of LeicesterUniversity Road Leicester LE1 7RH UK Tianjin Xiangtong Electronic Company LTD Tianjin 301800 China

We demonstrate an innovative preparation approach of diamond/Cu composites by powder-in-tube technique and rolling. A small copper tube was loaded with Ti- and Cu-coated diamond particles, mad then the diamond particles were combined with Cu matrix by composite rolling. The morphology and element distribution of the interface between diamond and Cu were determined by scanning electron microscopy and energy-dispersive spectrometer. Finite element method （FEM） simulation was used to analyze the rolling process associated with experiment by DEFORM-3D. The final experimental results showed that homogeneous distribution of diamond particles could be observed in the center layer of the composites. According to the contrast experiments, the sample, whose diamond particle size is 0.12-0.15 mm and thickness of pre-rolling is 1.2 mm, showed relatively complete morphologies and homogeneous distribution. Experimental results indicated a poor efficacy of excessive rolling reduction. The thermal conductivity of the composites is about 453 W （m K）-1 by theoretical calculation. For FEM simulation, roiling strain and temperature field of the composites were simulated by DEFORM-3D. Simulation results were interpreted, and numerical results verified the reliability of the model. The simulation predicted that the local area of large strain, indicative of the strain along the thickness direction, could be intensified by adding diamond particles.

关键词： Diamond/Cu composites Powder-in-tube technique (PIT) Rolling Finite element method(FEM) simulation

Gaussian limit for determinantal point processes with J-Hermitian kernels

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Science China Mathematics 2023年第6期66卷 1359-1374页

作者： Zhaofeng Lin Yanqi Qiu kai wang Shanghai Center for Mathematical Sciences Fudan UniversityShanghai 200438China Institute of Mathematics and Hua Loo-Keng Key Laboratory of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences Fudan UniversityShanghai 200433China

We show that the central limit theorem for linear statistics over determinantal point processes with J-Hermitian kernels holds under fairly general *** particular,we establish the Gaussian limit for linear statistics over determinantal point processes on the union of two copies of Rdwhen the correlation kernels are J-Hermitian translation-invariant.

关键词： determinantal point process J-Hermitian kernel linear statistics central limit theorem translation-invariantkernel

Recent advances in organic pressure-responsive luminescent materials

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Chinese Chemical Letters 2019年第11期30卷 1883-1894页

作者： Zhiyuan Fu kai wang Bo Zou State Key Laboratory of Superhard Materials College of PhysicsJilin University

Organic luminescent materials are very sensitive to external stimuli,such as pressure,temperature,and electric *** luminescent properties of some organic luminescent materials significantly change under high *** materials may show luminescence discoloration,whereas some may exhibit luminescence *** properties have many potential applications in anticounterfeiting,force sensor,data recording and storage,and luminescent devices,thereby greatly attracting the attention of *** this review,the progress of research on these materials at high pressure in recent years is summarized.

关键词： Pressure-responsive Piezochromic Diamond anvil cell Pressure-induced enhanced emission Organic luminescent

Local thresholding with adaptive window shrinkage in the contourlet domain for image denoising

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Science China(Information Sciences) 2013年第9期56卷 65-73页

作者： SHEN XiaoHong wang kai GUO Qiang School of Computer Science and Technology Shandong University of Finance and Economics Shandong Provincial Key Laboratory of Digital Media Technology Shandong University of Finance and Economics

Threshold selection is a challenging job for the image denoising in the contourlet domain. In this paper, a new local threshold with adaptive window shrinkage is proposed. According to the anisotropic energy clusters in contourlet subbands, local adaptive elliptic windows are introduced to determine the neighboring coefficients with strong dependencies for each coefficient. Utilizing the maximum likelihood estimator within the adaptive window, the signal variance is estimated from the noisy neighboring coefficients. Based on the signal variance estimation, the new threshold is obtained in the Bayesian framework. Since it makes full use of the captured directional information of images, the threshold extends to the anisotropic spatial adaptability and behaves reliably. Simulation experiments show that the new method exhibits better performance than other outstanding wavelet and contourlet denoising schemes obviously, both in the PSNR value and the visual appearance.

关键词： image denoising thresholding contourlet transform adaptive window directional selectivity