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Positive Solutions of a Class of Quasilinear Elliptic Equations in Two-dimensional Exterior Domains

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Acta Mathematica Sinica,English Series 2006年第3期22卷 819-826页

作者： zhao Yang yin Department of Mathematics Zhongshan University Department of Mathematics Lund University

Sufficient conditions for the existence of positive solutions to a class of quasilinear elliptic equations in two-dimensional exterior domains are given.

关键词： Positive solution Quasilinear elliptic equation Exterior domains

General series expression of eddy-current impedance for coil placed above multi-layer plate conductor

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Chinese Physics B 2018年第6期27卷 179-184页

作者： yin-zhao Lei School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China

This paper presents a closed expression of the layered-plate factor used to calculate the coil eddy-current impedance over the multi-layer plate conductor. By using this expression, the general series of eddy-current impedance can be written directly without solving the undetermined constant equations. The series expression is easy to use for theoretical analysis and programming. Experimental results show that calculated values and measured values are in agreement. As an application, when the bottom layer of the layered plate is a non-ferromagnetic thin layer conductor and the product of the thickness and conductivity of the layer remains unchanged, using the layered-plate factor expression proposed in this paper, it can be theoretically predicted that the eddy-current impedance curves corresponding to different thin layer thickness values will coincide.

关键词： multi-layer plate conductor layered-plate factor series expression eddy-current impedance

Non-parametric reconstruction of growth index via Gaussian processes

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Science China(Physics,Mechanics & Astronomy) 2019年第9期62卷 110-119页

作者： zhao-Yu yin Hao Wei School of Physics Beijing Institute of Technology

The accelerated cosmic expansion could be due to dark energy within general relativity(GR), or modified gravity. Differentiating between them using both the expansion history and growth history has attracted considerable attention. In the literature, the growth index γ has been found useful to distinguish these two scenarios. This work aims to consider the non-parametric reconstruction of the growth index γ as a function of redshift z from the latest observational data as of July 2018 via Gaussian processes. We found that f(R) theories and dark energy models within GR(especially ΛCDM) are inconsistent with the results in the moderate redshift range far beyond 3σ confidence level. A modified gravity scenario different from f(R) theories is favored. However, these results can also be due to other non-trivial possibilities in which dark energy models within GR(especially ΛCDM) and f(R) theories may still survive. In all cases, our results suggest that new physics is required.

关键词： cosmology dark energy modified gravity growth index Gaussian processes

On controllability and stabilizability of probabilistic Boolean control networks

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Science China(Information Sciences) 2014年第1期57卷 178-191页

作者： zhao yin CHENG DaiZhan Institute of Systems Science Chinese Academy of Sciences

The controllability of probabilistic Boolean control networks(PBCNs)is first *** the input-state incidence matrices of all models,we propose a reachability matrix to characterize the joint *** we prove that the joint reachability and the controllability of PBCNs are equivalent,which leads to a necessary and sufcient condition of the ***,the result of controllability is used to investigate the stability of probabilistic Boolean networks(PBNs)and the stabilization of PBCNs.A necessary and sufcient condition for the stability of PBNs is obtained *** introducing the control-fixed point of Boolean control networks(BCNs),the stability condition has finally been developed into a necessary and sufcient condition of the stabilization of *** necessary and sufcient conditions for controllability and stabilizability are based on reachability matrix,which are easily *** the two necessary and sufcient conditions are straightforward *** examples are provided from case to case to demonstrate the corresponding theoretical results.

关键词： probabilistic Boolean control network controllability stability stabilization semi-tensor product

Mapping determinants of rural poverty in Guangxi–a less developed region of China

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Journal of Mountain Science 2020年第7期17卷 1749-1762页

作者： zhao yin-jun LU Yuan Key Laboratory of Environment Change and Resources Use in Beibu Gulf Ministry of EducationNanning Normal UniversityNanning530001China School of Geography and Planning Nanning Normal UniversityNanning530001China

Rapid urbanization in China has led to an increasing imbalance in regional *** Guangxi Zhuang Autonomous Region,a less developed border region with unique cultural diversity,has a relatively large population(4.52 million people in 2015)under the poverty line,according to the national standard of *** has launched a national campaign to reduce poverty using a wide range of new development policies and large-scale ***,there have been few studies on the determinants of poverty at the county level across a *** paper aims to explore the spatial and social differences related to poverty among 109 counties by considering the spatial heterogeneity of poverty *** statistical models revealed that slope(Slp),GDP per capita(GDPP),the ethnic minority population ratio(EMPR),medical and technical personnel of healthcare institutions(MTP)and illiteracy rate(IR)significantly affect the patterns of the poverty rate,with a high adjusted R2(0.67),while the poverty rate affects GDPP,IR,MTP and EMPR;i.e.,the effects are ***,the IR is significantly affected by the provision of schools and transportation *** these determinants,social factors may be *** spatial patterns of these relationships demonstrate remarkable variation across the province and between minor and major *** quantitative evidence is enhanced by indepth interviews with selected *** results are expected to be useful for the anti-poverty project in Guangxi.

关键词： Determinants Ordinary least squares regression Geographically weighted regression Poverty Spatial distribution Guangxi

Improved thermoelectric performance in n-type BiTe facilitated by defect engineering

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Rare Metals 2021年第10期40卷 2829-2837页

作者： Hao Zhu Ji-yin zhao Chong Xiao Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China

BiTe is a potentially attractive candidate for thermoelectric applications because it is the structural analogue of the state-of-the-art thermoelectric material,bismuth telluride(Bi_(2)Te_(3)). However, BiTe has attracted little attention due to its small band gap and high electron concentration. In this study, remarkable increase in thermoelectric performance in the n-type Bi_(1-x)Sb_(x)Te compounds through tuning the carrier concentration with chemical doping is shown. The Seebeck coefficient of Bi_(1-x)Sb_(x)Te increases remarkably while the electronic thermal conductivity decreases gradually as Sb content is increased, leading to enhanced thermoelectric figure of merit(ZT). Moreover, the simultaneous optimization of the electrical and thermal transport properties leads the peak temperature of the figure of merit to shift toward lower temperature with Sb content increasing in Bi_(1-x)Sb_(x)Te, thus making Bi_(1-x)Sb_(x)Te a potential alternative to bismuth telluride for near-room-temperature thermoelectric applications. In addition, the presence of multiple low-frequency optical phonons and their coupling with the long-wavelength heat carrying acoustic phonons in all the Bi_(1-x)Sb_(x)Te investigated are revealed based on the combined Debye-Einstein model. The present results provide the underlying mechanism connecting thermoelectric performance and lattice dynamics in Bi_(1-x)Sb_(x)Te compounds.

关键词： BiTe Thermoelectric material Carrier concentration Defect engineering Einstein oscillators Near-room-temperature application

Global Well-posedness for the Non-viscous MHD Equations with Magnetic Diffusion in Critical Besov Spaces

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Acta Mathematica Sinica,English Series 2022年第9期38卷 1493-1511页

作者： Wei Kui YE zhao Yang yin Institute of Applied Physics and Computational Mathematics P.O.Box 8009Beijing 100088P.R.China Department of Mathematics Sun Yat-sen UniversityGuangzhou 510275P.R.China

In this paper,we mainly investigate the Cauchy problem of the non-viscous MHD equations with magnetic *** first establish the local well-posedness(existence,uniqueness and continuous dependence)with initial data(u_(0),b_(0))in critical Besov spaces B_(p,1)^(d/p+1)×B_(p,1)^(d/p)with 1≤p≤∞,and give a lifespan T of the solution which depends on the norm of the Littlewood–Paley decomposition(profile)of the initial ***,we prove the global existence in critical Besov *** particular,the results of global existence also hold in Sobolev space C([0,∞);H~s(S~2))×(C([0,∞);H^(s-1)(S~2))∩L~2([0,∞);H~s(S~2)))with s>2,when the initial data satisfies∫_(S~2)b_(0)dx=0 and||u_(0)||B_(()∞,1~((S~2)))~1+||b_(0)||B_(()∞,1^(S~2))~0≤ε.It’s worth noting that our results imply some large and low regularity initial data for the global existence.

关键词： The non-viscous MHD equations with magnetic diffusion local well-posedness critical Besov spaces global existence

Coupling mechanism of multi-force interactions in the myosin molecular motor

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Chinese Science Bulletin 2010年第31期55卷 3538-3544页

作者： GUO zhao yin YueHong State Key Laboratory of Mechanism System and Vibration Institute of Robotics Shanghai Jiao Tong University Shanghai 200240 China

The dynamics of the myosin molecular motor as it binds to actin filaments during muscle contraction are still not clearly *** this paper,we focus on the coupling mechanism of multi-force interactions in the myosin molecule during its interaction with *** forces include the electrostatic force,the van der Waals force and the Casimir force in molecular dynamic simulations of the molecules in solvent with thermal *** on the Hamaker approach,van der Waals and Casimir potentials and forces are calculated between myosin and *** have developed a Monte Carlo method to simulate the dynamic activity of the molecular *** have shown that because of the retardation effect,the van der Waals force falls into the Casimir force when the distance between the surfaces is larger than 3 *** the distance is smaller than 3 nm,the electrostatic force and the van der Waals force increase until the myosin becomes attached to the *** the distances studied in the present work,the electrostatic force dominates the attractive *** calculations are in good agreement with recently reported experimental results.

关键词：肌球蛋白分子马达相互作用耦合机制分子动力学模拟 Casimir力肌动蛋白范德华力

A new source extraction algorithm for optical space debris observation

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Research in Astronomy and Astrophysics 2013年第5期13卷 604-614页

作者： Rong-Yu Sun Chang-yin zhao Purple Mountain Observatory Chinese Academy of Sciences Key Laboratory of Space Object and Debris Observation Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Specific challenges arise in the task of real-time automatic data reduction of optical space debris observations. Here we present an automatic technique that optimally detects and measures the sources from images of optical space debris ob- servations. We show that highly reliable and accurate results can be obtained on most images produced by our specific sensors, and due to optimizations, the whole pipeline works fast and efficiently. Tests demonstrate that the technique performs better than SExtractor from the point of view of fast and accurate detection, therefore it is well suited for data reduction of optical space debris observations.

关键词： techniques: image processing -- space vehicles -- astrometry