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Convex hull theorem for multiply connected domains in the plane with an estimate of the quasiconformal constant

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Science China Mathematics 2009年第5期52卷 932-940页

作者： LIU gang wu ShengJian LMAM School of Mathematical SciencesPeking UniversityBeijing 100871China

For any multiply connected domain Ω in ?2, let S be the boundary of the convex hull in H 3 of ?2Ω which faces Ω. Suppose in addition that there exists a lower bound l > 0 of the hyperbolic lengths of closed geodesics in Ω. Then there is always a K-quasiconformal mapping from S to Ω, which extends continuously to the identity on ?S = ?Ω, where K depends only on l. We also give a numerical estimate of K by using the parameter l.

关键词： convex hull quasiconformal mapping multiply connected domain 30C62

A secure rational quantum state sharing protocol

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Science China(Information Sciences) 2018年第2期61卷 204-215页

作者： Zhao DOU gang XU Xiu-Bo CHEN Xin LIU Yi-xian YANG Information Security Center State Key Laboratory of Networking and Switching TechnologyBeijing University of Posts and Telecommunications School of Software Engineering Beijing University of Posts and Telecommunications School of Information Engineering Inner Mongolia University of Science and Technology School of Computer Science Shaanxi Normal University Gui Zhou University Guizhou Provincial Key Laboratory of Public Big Data

A novel rational protocol to share two arbitrary qubits among multiple parties is investigated in this paper. First, the protocol is presented, which is learned from Li et al.’s protocol. Second, the utility,security, correctness, fairness, Nash equilibrium, and Pareto optimality of our scheme are discussed in detail,where the utility, correctness, and fairness of rational quantum state sharing protocols are creatively given because the agent who recovers the state plays a different and more important role. Another important point is that assumptions about our protocol are more practical and suitable than existing protocols.

关键词： rational quantum state sharing Nash equilibrium secure correct

Tetrabenzotriazacorrole and its derivatives as undopea hole transporting materials for perovskite solar cells:Synthesis,device fabrication,and device performance

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Journal of Energy Chemistry 2020年第4期29卷 139-147页

作者： xian-Fu Zhang Chang Liu Jianchang wu Baomin Xu Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055GuangdongChina Institute of Applied Photochemistry Hebei Normal University of Science and TechnologyQinhuangdao 066004HebeiChina Shenzhen Engineering Research and Development Center for Flexible Solar Cells Southern University of Science and TechnologyShenzhen 518055GuangdongChina

Phosphorous tetrabenzotriazacorrole(TBC)and its two soluble derivatives(TBC-1 and TBC-2)were synthesized and used for the first time as undoped hole transporting materials(HTMs)in MAPbI3 perovskite solar cells(PSCs).Their performance in PSCs was measured and compared with that of SpiroOMeTAD and phthalocyanine *** fundamental properties related to HTMs are also *** novel HTMs are easily prepared,cost-effective,and solution *** materials exhibited much higher hole transport mobility and broader light absorption than pristine Spiro-OMeTAD and phthalocyanine *** can work efficiently in the absence of any dopant for devices composed of FTO/cp-TiO2/mp-TiO2/MAPbI3/HTM/*** undoped mesoscopic solar cell devices based on TBC exhibited a promising power conversion efficiency(PCE)of up to 16.2%(measured at 100 mWcm2 illumination,AM 1.5 G),together with good long-term stability under ambient *** PCE of 16.2%observed using TBC is remarkably higher than the 11.2%observed using undoped Spiro-OMeTAD and also much better than the 8.70%observed using its phthalocyanine *** to substitution effects,α-substituted TBC-1 was found to be a better HTM thanβ-substituted TBC-2(PCE 11.4%)and unsubstituted TBC-3(PCE 6.81%)under the same *** results provide the basis for further exploiting TBC compounds as a new type of low-cost and effective HTM for PSCs.

关键词： Perovskite solar cell Hole transporting material Tetrabenzotriazacorrole Phthalocyanine

Reverse-transformation austenite structure control with micro/nanometer size

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International Journal of Minerals,Metallurgy and Materials 2017年第5期24卷 530-537页

作者： Hui-bin wu gang Niu Feng-juan wu Di Tang Collaborative Innovation Center of Steel Technology University of Science and Technology Beijing Beijing Engineering Technology Research Center of Special Steel for Traffic and Energy

To control the reverse-transformation austenite structure through manipulation of the micro/nanometer grain structure, the influences of cold deformation and annealing parameters on the microstructure evolution and mechanical properties of 316L austenitic stainless steel were investigated. The samples were first cold-rolled, and then samples deformed to different extents were annealed at different temperatures. The microstructure evolutions were analyzed by optical microscopy, scanning electron microscopy (SEM), magnetic measurements, and X-ray diffraction (XRD); the mechanical properties are also determined by tensile tests. The results showed that the fraction of stain-induced martensite was approximately 72% in the 90% cold-rolled steel. The micro/nanometric microstructure was obtained after reversion annealing at 820-870A degrees C for 60 s. Nearly 100% reversed austenite was obtained in samples annealed at 850A degrees C, where grains with a diameter ae 500 nm accounted for 30% and those with a diameter > 0.5 mu m accounted for 70%. The micro/nanometer-grain steel exhibited not only a high strength level (approximately 959 MPa) but also a desirable elongation of approximately 45%.

关键词： austenitic stainless steel structure control martensite reverse transformation grain refinement

Thermodynamic simulation of the effect of slag chemistry on the corrosion behavior of alumina–chromia refractory

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International Journal of Minerals,Metallurgy and Materials 2016年第12期23卷 1458-1465页

作者： Shi-xian Zhao Bin-li Cai Hong-gang Sun gang Wang Hong-xia Li Xiao-yan Song State Key Laboratory of Advanced Refractories Sinosteel Luoyang Institute of Refractories Research Co. Ltd. School of Materials Science and Engineering Beijing University of Technology

The corrosion behavior of alumina-chromia refractory against two kinds of industrial slags （coal slag and iron smelting slag） at 1550℃ was investigated via thermodynamic simulations. In the proposed simulation model, the initial slag first attacks the matrix and surface aggregates and subsequently attacks the inner aggregates. The simulation results indicate that the slag chemistry strongly affects the phase formation and corrosion behavior of the refractory brick. Greater amounts of alumina were dissolved and spinel solid phases formed when the brick interacted with iron smelting slag. These phenomena, as well as the calculated lower viscosity, may lead to much deeper penetration than that exhibited by coal slag and to more severe corrosion compared to that induced by coal slag. The thermodynamic calculations well match the experimental observations, demonstrating the efficiency of the proposed simulation model for evaluating the corrosion behavior of alumina-chromia refractory.

关键词： thermodynamic analysis simulation corrosion spinel alumina chromia refractories

Retrospective analysis of pathological types and imaging features in pancreatic cancer: A comprehensive study

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World Journal of Gastrointestinal Oncology 2025年第1期17卷 121-129页

作者： Yang-gang Luo Mei wu Hong-Guang Chen Pathology Department Xuanhan County People’s HospitalDazhou 636150Sichuan ProvinceChina

BACKGROUND Pancreatic cancer remains one of the most lethal malignancies worldwide,with a poor prognosis often attributed to late *** the correlation between pathological type and imaging features is crucial for early detection and appropriate treatment *** To retrospectively analyze the relationship between different pathological types of pancreatic cancer and their corresponding imaging *** We retrospectively analyzed the data of 500 patients diagnosed with pancreatic cancer between January 2010 and December 2020 at our *** types were determined by histopathological examination of the surgical spe-cimens or biopsy *** imaging features were assessed using computed tomography,magnetic resonance imaging,and endoscopic *** analyses were performed to identify significant associations between pathological types and specific imaging *** There were 320(64%)cases of pancreatic ductal adenocarcinoma,75(15%)of intraductal papillary mucinous neoplasms,50(10%)of neuroendocrine tumors,and 55(11%)of other rare *** imaging features were identified in each pathological *** ductal adenocarcinoma typically presents as a hypodense mass with poorly defined borders on computed tomography,whereas intraductal papillary mucinous neoplasms present as characteristic cystic lesions with mural *** tumors often appear as hypervascular lesions in contrast-enhanced *** analysis revealed significant correlations between specific imaging features and pathological types(P<0.001).CONCLUSION This study demonstrated a strong association between the pathological types of pancreatic cancer and imaging *** findings can enhance the accuracy of noninvasive diagnosis and guide personalized treatment approaches.

关键词： Pancreatic cancer Pathological types Imaging features Retrospective analysis Diagnostic accuracy

Nonlinear dynamics analysis of a new autonomous chaotic system

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第9期8卷 1408-1413页

作者： CHU Yan-dong LI xian-feng ZHANG Jian-gang CHANG Ying-xiang School of Mathematics Physics and Software Engineering Lanzhou Jiaotong University Lanzhou 730070 China Nonlinear Science Research Center Lanzhou Jiaotong University Lanzhou 730070 China

In this paper,a new nonlinear autonomous system introduced by Chlouverakis and Sprott is studied further,to present very rich and complex nonlinear dynamical behaviors. Some basic dynamical properties are studied either analytically or nu-merically,such as Poincaré map,Lyapunov exponents and Lyapunov dimension. Based on this flow,a new almost-Hamilton chaotic system with very high Lyapunov dimensions is constructed and investigated. Two new nonlinear autonomous systems can be changed into one another by adding or omitting some constant coefficients.

关键词： Lyapunov exponents Bifurcation Chaos Phase space Poincaré sections

Pythagorean probabilistic hesitant triangular fuzzy aggregation operators with applications in multiple attribute decision making

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Journal of Systems Engineering and Electronics 2023年第2期34卷 422-438页

作者： LIAO Fuping LI wu LIU gang ZHOU Xiaoqiang School of Information Science and Engineering Hunan Institute of Science and TechnologyYueyang 414006China

As a generalization of fuzzy set,hesitant probabilistic fuzzy set and pythagorean triangular fuzzy set have their own unique advantages in describing decision *** modern socioeconomic decision-making problems are becoming more and more complex,it also becomes more and more difficult to appropriately depict decision makers’cognitive information in decision-making *** order to describe the decision information more comprehensively,we define a pythagorean probabilistic hesitant triangular fuzzy set(PPHTFS)by combining the pythagorean triangular fuzzy set and the probabilistic hesitant fuzzy ***,the basic operation and scoring function of the pythagorean probabilistic hesitant triangular fuzzy element(PPHTFE)are proposed,and the comparison rule of two PPHTFEs is ***,some pythagorean probabilistic hesitant triangular fuzzy aggregation operators are developed,and their properties are also ***,a multi-attribute decision-making(MADM)model is constructed based on the proposed operators under the pythagorean probabilistic hesitant triangular fuzzy information,and an illustration example is given to demonstrate the practicability and validity of the proposed decision-making method.

关键词： pythagorean probabilistic hesitant triangular fuzzy set(PPHTFS) aggregation operator multi-attribute decisionmaking(MADM)

Range-spread target detector via coherent energy accumulation and block thresholding denoising

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Journal of Systems Engineering and Electronics 2021年第4期32卷 873-880页

作者： ZHANG Yunjian PAN Pingping DENG Zhenmiao wu gang School of Electronics and Communication Engineering Sun Yat-sen UniversityGuangzhou 510275China Jiuquan Satellite Launch Center Dunhuang 736200China

A range-spread target(RST)detector is proposed for wideband *** detector,referred to as a conjugate multiplication and block thresholding(CMBT)detector,is simple for implementation in existing radar systems and has the advantage of minor ***,the target energy of adjacent stretched echoes is coherently accumulated via conjugate multiplication and Fourier transform *** is noted that conjugate multiplication of two complex Gaussian distributed noise is complex double Gaussian distributed,leading to a signal to noise ratio(SNR)***,considering the sparsity and clustering characteristics of the conjugate multiplication amplitude spectrum(CMAS),the block thresholding method is adopted for denoising,where the noise and cross-terms are adaptively smoothed,and the signal terms can be basically ***,numerical simulation results for both synthetic and real radar data validate the effectiveness of the proposed detector,comparing with the conventional integration detector(ID),the spatial scattering density(SSD)detector,and waveform entropy(WE)and waveform contrast(WC)based detectors.

关键词： wideband radar detection range-spread target conjugate multiplication block thresholding denoising