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Computing knots by quadratic and cubic polynomial curves

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Computational Visual Media 2020年第4期6卷 417-430页

作者： fan Zhang Jinjiang Li Peiqiang Liu Hui fan School of Computer Science and Technology Shandong Technology and Business UniversityYantai 264005China Co-Innovation Center of Shandong Colleges and Universities:Future Intelligent Computing Yantai 264005China

A new method is presented to determine parameter values(knot)for data points for curve and surface *** four adjacent data points,a quadratic polynomial curve can be determined uniquely if the four points form a convex *** the four data points do not form a convex polygon,a cubic polynomial curve with one degree of freedom is used to interpolate the four points,so that the interpolant has better shape,approximating the polygon formed by the four data *** degree of freedom is determined by minimizing the cubic coefficient of the cubic polynomial *** advantages of the new method are,firstly,the knots computed have quadratic polynomial precision,i.e.,if the data points are sampled from a quadratic polynomial curve,and the knots are used to construct a quadratic polynomial,it reproduces the original quadratic ***,the new method is affine invariant,which is significant,as most parameterization methods do not have this ***,it computes knots using a local *** show that curves constructed using knots computed by the new method have better interpolation precision than for existing methods.

关键词： knot interpolation polynomial curve affine invariant

Complete Universal Scaling in First-Order Phase Transitions

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Chinese Physics Letters 2024年第10期41卷 8-13页

作者： fan Zhong School of Physics and State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-sen UniversityGuangzhou 510275China

Phase transitions and critical phenomena are among the most intriguing phenomena in nature and *** are classified into first-order phase transitions(FOPTs)and continuous *** the latter shows marvelous phenomena of scaling and universality,whether the former behaves similarly is a long-standing controversial *** we definitely demonstrate complete universal scaling in field driven FOPTs for Langevin equations in both zero and two spatial dimensions by rescaling all parameters and subtracting nonuniversal contributions with singular dimensions from an effective temperature and a special field according to an effective *** offers a perspective different from the usual nucleation and growth but conforming to continuous phase transitions to study FOPTs.

关键词： theory. transitions scaling

Compressive elastic behavior of single-crystalline 4H-silicon carbide(SiC) nanopillars

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Science China(Technological Sciences) 2021年第1期64卷 37-43页

作者： fan SuFeng LI XiaoCui fan Rong LU Yang Department of Mechanical Engineering City University of Hong KongHong Kong 999077China Department of Materials Science and Engineering City University of Hong KongHong Kong 999077China Nanomanufacturing Laboratory(NML) Center for Advanced Structural Materials(CASM)City University of Hong Kong Shenzhen Research InstituteShenzhen 518057China

As a wide-bandgap semiconductor, 4H-SiC is an ideal material for high-power and high-frequency devices, and plays an increasingly important role in developing our country’s future electric vehicles and 5G techniques. Practical applications of SiCbased devices largely depend on their mechanical performance and reliability at the micro-and nanoscales. In this paper, singlecrystal [0001]-oriented 4H-SiC nanopillars with the diameter ranging from ~200 to 700 nm were microfabricated and then characterized by in situ nanomechanical testing under SEM/TEM at room temperature. Loading-unloading compression tests were performed, and large, fully reversible elastic strain up to ~6.2% was found in nanosized pillars. Brittle fracture still occurred when the max strain reached ~7%, with corresponding compressive strength above 30 GPa, while in situ TEM observation showed few dislocations activated during compression along the [0001] direction. Besides robust microelectromechanical system(MEMS), flexible device and nanocomposite applications, the obtained large elasticity in [0001]-oriented 4H-SiC nanopillars can offer a fertile opportunity to modulate their electron mobility and bandgap structure by nanomechanical straining,the so called "elastic strain engineering", for novel electronic and optoelectronic applications.

关键词： silicon carbide elastic deformation compressive behavior in situ SEM/TEM elastic strain engineering

Spatial identification and scenario simulation of the ecological transition zones under the climate change in China

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Journal of Geographical Sciences 2021年第4期31卷 497-517页

作者： fan Zemeng State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

Explicitly identifying the spatial distribution of ecological transition zones(ETZs)and simulating their response to climate scenarios is of significance in understanding the response and feedback of ecosystems to global climate *** this study,a quantitative spatial identification method was developed to assess ETZ distribution in terms of the improved Holdridge life zone(iHLZ)*** on climate observations collected from 782 weather stations in China in the T0(1981–2010)period,and the Intergovernmental Panel on Climate Change Coupled Model Intercomparison Project(IPCC CMIP5)RCP2.6,RCP4.5,and RCP8.5 climate scenario data in the T1(2011–2040),T2(2041–2070),and T3(2071–2100)periods,the spatial distribution of ETZs and their response to climate scenarios in China were simulated in the four periods of T0,T1,T2,and ***,a spatial shift of mean center model was developed to quantitatively calculate the shift direction and distance of each ETZ type during the periods from T0 to *** simulated results revealed 41 ETZ types in China,accounting for 18%of the whole land *** temperate grassland/humid forest and warm temperate arid forest(564,238.5 km~2),cold temperate humid forest and warm temperate arid/humid forest(566,549.75 km~2),and north humid/humid forest and cold temperate humid forest(525,750.25 km~2)were the main ETZ types,accounting for 35%of the total ETZ area in *** 2010 and 2100,the area of cold temperate desert shrub and warm temperate desert shrub/thorn steppe ETZs were projected to increase at a rate of 4%per decade,which represented an increase of 3604.2,10063.1,and 17,242 km~2 per decade under the RCP2.6,RCP4.5,and RCP8.5 scenarios,*** cold ETZ was projected to transform to the warm humid ETZ in the *** average shift distance of the mean center in the north wet forest and cold temperate desert shrub/thorn grassland ETZs was generally larger than that of other ETZs,with the mean center moving to the n

关键词： ecological transition zone mean center spatial identification model scenario simulation China

The detection of gravitational waves and the new era of multi-messenger astronomy

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Science China(Physics,Mechanics & Astronomy) 2016年第4期59卷 90-92页

作者： XiLong fan School of Physics and Electronics Information Hubei University of Education

For the first time,gravitational waves(GWs),a major prediction of Einstein’s 1915 general theory of relativity(GR),has been detected directly by the two detectors of the Laser Interferometer Gravitational-Wave Observ... 详细信息

关键词：引力波探测天文学信使广义相对论爱因斯坦激光干涉 GWS 天文台

Calculation method of ship collision force on bridge using artificial neural network

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第5期9卷 614-623页

作者： Wei fan Wan-cheng YUAN Qi-wu fan State Key Laboratory for Disaster Reduction in Civil Engineering Tongji University Shanghai 200092 China Department of Civil Engineering Southwest Jiaotong University Chengdu 610031 China

Ship collision on bridge is a dynamic process featured by high nonlinearity and instantaneity. Calculating ship-bridge collision force typically involves either the use of design-specification-stipulated equivalent static load, or the use of finite element method (FEM) which is more time-consuming and requires supercomputing resources. In this paper, we proposed an alternative approach that combines FEM with artificial neural network (ANN). The radial basis function neural network (RBFNN) employed for calculating the impact force in consideration of ship-bridge collision mechanics. With ship velocity and mass as the input vectors and ship collision force as the output vector, the neural networks for different network parameters are trained by the learning samples obtained from finite element simulation results. The error analyses of the learning and testing samples show that the proposed RBFNN is accurate enough to calculate ship-bridge collision force. The input-output relationship obtained by the RBFNN is essentially consistent with the typical empirical formulae. Finally, a special toolbox is developed for calculation efficiency in application using MATLAB software.

关键词： Ship-bridge collision force Finite element method (FEM) Artificial neural network (ANN) Radial basis function neural network (RBFNN)

Catalytic reduction of NO_x by biomass-derived activated carbon supported metals

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Chinese Journal of Chemical Engineering 2018年第10期26卷 2077-2083页

作者： Yun Shu fan Zhang fan Wang Hongmei Wang Research Center of Air Pollution Control Technology Chinese Research Academy of Environmental Sciences

In this study,to prepare a series of activated carbon-supported metals for the catalytic reduction of NO_x to N_2 in excess O_2,activated carbons derived from lignocellulosic and herbaceous biomasses were selected as the reducing agents,and alkali and transition metals were used as the catalytic active *** effects of the type of biomass,carbonization temperature and catalyst composition on NO_x reduction efficiency were analyzed in a fixed-bed flow *** results showed that two temperature regimes are present for the NO_x-carbon reaction:at temperatures below 250°C,the NO_x adsorption process on the carbon surface was predominant,whereas true NO_x reduction by carbon occurred at temperatures above 250°C,producing N_2,CO_2 and *** influence of the carbonization temperature on carbon reactivity depended on the effect of the carbonization temperature on the carbon surface area and the reduction of the metal species on *** studied metals catalyzed both NO_xand O_2reduction by carbon,and potassium could strongly enhance the C-NO_x reaction without substantial carbon consumption by O_***,the potassium supported by sawdust-derived activated carbon exhibited higher selectivity and capacity towards NO_x reduction than did its previously reported coal-derived *** properties were ascribed to the high dispersion of the active potassium species on the carbon surface,as observed through the comparison of X-ray photoelectron spectroscopy and powder X-ray diffraction results for the carbons made from biomass and coal-based precursors.

关键词： Biomass NOx reduction Activated carbon Selectivity

Ce and Se co-doped MBG/SA/HLC microgel bone powder for repairing tumor bone defects

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Nano Research 2023年第1期16卷 746-756页

作者： Miaolin fan Wan Liu Cuiying fan Xiaoyan Zheng Junfeng Hui Chaoquan Hu Daidi fan Shaanxi Key Laboratory of Degradable Biomedical Materials Shaanxi R&D Center of Biomaterials and Fermentation EngineeringSchool of Chemical EngineeringNorthwest UniversityXi’an 710069China Biotech.&Biomed.Research Institute Northwest UniversityXi’an 710069China Xi’an Giant Biogene Technology Co. Ltd.Xi’an 710069China Nanjing IPE Institute of Green Manufacturing Industry Nanjing 211100China

The repair and treatment of tumor bone defects is a difficult problem to solve urgently in clinical *** tumor resection,patients are not only faced with a large area of bone defect,but also may have the risk of tumor recurrence,which can easily cause huge physical and mental harm to *** this study,we successfully designed and constructed an organic/inorganic composite microgel bone powder(S-H-M3%Ce/3%Se)based on cerium(Ce)and selenium(Se)elements co-doped mesoporous bioactive glass(M3%Ce/3%Se),sodium alginate(SA),and recombinant human-like collagen(HLC).The obtained S-H-M3%Ce/3%Se could inhibit the growth of osteoma cells and promote the growth of normal cells,and effectively promote the repair of defect *** integration of the“treatment and repair”organic/inorganic composite microgel bone powder provided a new strategy for the treatment of cancerous bone defects.

关键词： mesoporous bioactive glass functional elements osteoma inhibition bone repair

Effect of swirling flow on platelet concentration distribution in small-caliber artificial grafts and end-to-end anastomoses

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Acta Mechanica Sinica 2011年第5期27卷 833-839页

作者： fan Zhan Yu-Bo fan Xiao-Yan Deng Key Laboratory for Biomechanics and Mechanobiologyof Ministry of Education School of Biological Science and Medical EngineeringBeihang University 100191 Beijing China

Platelet concentration near the blood vessel wall is one of the major factors in the adhesion of platelets to the *** our previous studies,it was found that swirling flows could suppress platelet adhesion in small-caliber artificial grafts and end-to-end *** order to better understand the beneficial effect of the swirling flow,we numerically analyzed the near-wall concentration distribution of platelets in a straight tube and a sudden tubular expansion tube under both swirling flow and normal flow *** numerical models were created based on our previous experimental *** simulation results revealed that when compared with the normal flow,the swirling flow could significantly reduce the near-wall concentration of platelets in both the straight tube and the expansion *** present numerical study therefore indicates that the reduction in platelet adhesion under swirling flow conditions in small-caliber arterial grafts,or in end-to-end anastomoses as observed in our previous experimental study,was possibly through a mechanism of platelet transport,in which the swirling flow reduced the near-wall concentration of platelets.

关键词： Platelet near-wall concentration · Swirling flow · Small-caliber arterial grafts · End-to-end anastomosis