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An implicit symmetry constraint of the modified Korteweg-de Vries (mKdV) equation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第10期9卷 1457-1462页

作者： Ying YOU Jing yu qiao-yun JIANG Department of Mathematics Zhejiang University Hangzhou 310027 China School of Science Hangzhou Dianzi University Hangzhou 310018 China College of Science Nantong University Nantong 226007 China

In this paper, an implicit symmetry constraint is calculated and its associated binary nonlinearization of the Lax pairs and the adjoint Lax pairs is carried out for the modified Korteweg-de Vries (mKdV) equation. After introducing two new inde-pendent variables, we find that under the implicit symmetry constraint, the spatial part and the temporal part of the mKdV equation are decomposed into two finite-dimensional systems. Furthermore we prove that the obtained finite-dimensional systems are Hamiltonian systems and completely integrable in the Liouville sense.

关键词： Implicit symmetry constraint Completely integrable Hamiltonian system Modified Korteweg-de Vries (mKdV) equation

Hot deformation characteristics of as-cast high-Cr ultra-super-critical rotor steel with columnar grains

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International Journal of Minerals,Metallurgy and Materials 2016年第11期23卷 1275-1285页

作者： Zong-ye Ding qiao-dan Hu Long zeng Jian-guo Li School of Materials Science and Engineering Shanghai Jiao Tong University Laboratory of Advanced Materials and Solidification Shanghai Jiao Tong University

Isothermal hot compression tests of as-cast high-Cr ultra-super-critical（USC） rotor steel with columnar grains perpendicular to the compression direction were carried out in the temperature range from 950 to 1250°C at strain rates ranging from 0.001 to 1 s^（-1）. The softening mechanism was dynamic recovery（DRV） at 950°C and the strain rate of 1 s^（-1）, whereas it was dynamic recrystallization（DRX） under the other conditions. A modified constitutive equation based on the Arrhenius model with strain compensation reasonably predicted the flow stress under various deformation conditions, and the activation energy was calculated to be 643.92 kJ ×mol^（-1）. The critical stresses of dynamic recrystallization under different conditions were determined from the work-hardening rate（θ）–flow stress（σ） and-θ/σ–σ curves. The optimum processing parameters via analysis of the processing map and the softening mechanism were determined to be a deformation temperature range from 1100 to 1200°C and a strain-rate range from 0.001 to 0.08 s^（-1）, with a power dissipation efficiency η greater than 31%.

关键词： rotor steel columnar grains dynamic recrystallization constitutive models critical conditions processing maps

Optimal timing of invasive intervention for high-risk non-ST-segment-elevation myocardial infarction patients

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Journal of Geriatric Cardiology 2024年第8期21卷 807-815页

作者： Juan-Juan ZHENG yue-qiao SI Tian-Yang XIA Bing-Jun LU Chun-yu zeng Wei-Eric WANG Department of Geriatrics Southwest HospitalThird Military Medical UniversityChongqingChina Department of Cardiology Daping HospitalThird Military Medical UniversityChongqingChina

OBJECTIVE To compare the immediate,early,and delayed percutaneous coronary intervention(PCI)strategies in non-ST-segment-elevation myocardial infarction(NSTEMI)patients with *** Medical records of patients treated at the Daping Hospital,Third Military Medical University,Chongqing,China between 2011 and 2021 were retrospectively *** patients with complete available information were *** patients assigned into three groups based on the timing of PCI including immediate(<2 h),early(2–24 h)and delayed(≥24 h)*** Cox hazards regression and simpler nonlinear models were *** A total of 657 patients were included in the *** median follow-up length was 3.29(interquartile range:1.45–4.85)*** PCI strategy improved the major adverse cardiac event(MACE)outcome compared to the immediate or delayed PCI *** PCI,diabetes mellitus,and left main or/and left anterior descending or/and left circumflex stenosis or/and right coronary artery≥99%were predictors for MACE *** optimal timing range for PCI to reduce MACE risk is 3–14 h *** high-risk NSTEMI patients,early PCI reduced primary clinical outcomes compared to immediate or delayed PCI,and the optimal timing range was 3–14 h *** PCI was superior for NSTEMI with chronic kidney *** Delayed invasive strategy was helpful to reduce the incidence of MACE for high-risk NSTEMI with chronic kidney *** immediate PCI strategy might increase the rate of MACE.

关键词： patients infarction Chongqing

A one-pot method for controlled synthesis and selective etching of organic-inorganic hybrid perovskite crystals

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Journal of Energy Chemistry 2019年第6期28卷 149-154页

作者： yu Hou Mengjiong Chen Hongwei qiao Huagui Yang Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials Science and Engineering East China University of Science and Technology

Organometal halide perovskites have recently emerged with a huge potential for photovoltaic applications. Moreover, preparation of high-quality perovskite crystals with controlled morphology is of great significance for the fundamental studies such as optical and electrical properties, as well as the applications. Here, we report a one-pot solvothermal process to synthesize sheet-shaped CH3NH3PbBr3 single crystals with the lateral size of 100 μm and the thickness of 3–8 μm. Furthermore, a controlled etching behavior on the crystalline surface was demonstrated, which could be the irregular collapse of the crystalline surface caused by the local accumulation of methylammonium cations. Using this technique,CH3NH3PbBr3 single crystal sheets could be used in the various optoelectronic devices, such as nanolaser,optical sensors, photodetectors and field effect transistors.

关键词： Crystal growth Perovskite Solvothermal Etching effect

Do cooperatives participation and technology adoption improve farmers’welfare in China?A joint analysis accounting for selection bias

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Journal of Integrative Agriculture 2021年第6期20卷 1716-1726页

作者： YANG Dan ZHANG Hui-wei LIU Zi-min zeng qiao College of Economics and Management Southwest UniversityChongqing 400716P.R.China School of Business Chongqing College of HumanitiesScience and TechnologyChongqing 401524P.R.China

This study examines the impact of farmers’cooperatives participation and technology adoption on their economic welfare in China.A double selectivity model(DSM)is applied to correct for sample selection bias stemming from both observed and unobserved factors,and a propensity score matching(PSM)method is applied to calculate the agricultural income difference with counter factual analysis using survey data from 396 farmers in 15 provinces in *** findings indicate that farmers who join farmer cooperatives and adopt agricultural technology can increase agricultural income by 2.77 and 2.35%,respectively,compared with those non-participants and ***,the effect on agricultural income is found to be more significant for the low-income farmers than the high-income ones,with income increasing 5.45 and 4.51%when participating in farmer cooperatives and adopting agricultural technology,*** findings highlight the positive role of farmer cooperatives and agricultural technology in promoting farmers’economic *** on the findings,government policy implications are also discussed.

关键词： cooperatives double selectivity model propensity score matching sample selection bias technology adoption welfare improvement

Numerical Investigation of Boundary Grid Effect on Heat Transfer Computation of RP-3 at Supercritical Temperature of Helical Tube Wall

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Journal of Thermal Science 2021年第2期30卷 504-516页

作者： LIU Shaobei BAO Zewei HUANG Weixing zeng Tao qiao Min MENG Jiancheng School of Chemical Engineering Sichuan UniversityChengdu 610065China School of Mechanical Engineering Sichuan University of Science&EngineeringZigong 643000China Sichuan Provincial Key Lab of Process Equipment and Control Zigong 643000China

To get reliable computational results,the RNG k-ε turbulence model with enhanced wall treatment was validated to solve the heat transfer of supercritical RP-3 in a helically coiled tube,and models of the thermo-physical properties of RP-3 were optimally *** significantly,the grid independence was validated by two-step procedure,and the effect of boundary grids of the supercritical-temperature wall on the computational accuracy was well *** adjusting boundary-layer girds' size,four regions (increased,pseudo-convergence,decreased and convergence) of the outlet temperature Tout were obtained and *** results showed that the maximum computation errors of Tout and the pressure differential between the inlet and outlet ΔP reached 20.65% and 98.15%,respectively,indicating that boundary grids have a significant influence on computation of flow and heat *** on this,a dimensionless distance from the wall-adjacent cell to the wall y+=Prw-1/1.78 (Prw denotes Wall Prandtl number) was recommended as a convergence *** variation laws of viscous length scale y* were discussed under different structural parameters,operation parameters,and helical *** explicit model of y* was proposed to calculate the height (y) of the first boundary layer grids and refine boundary grids efficiently.A modified model for coefficient of fiiction factor Cf was proposed based on Rogers's,and Nusselt number Nu was proposed based on an analogy of momentum and heat *** above models about y*,Cf and Nu could apply to both the entrance region and the whole tube length,and showed good performance when Reynolds number was extended to above 70 000,or whenever the outlet temperature is below or above the critical point.

关键词： supercritical heat transfer helically coiled tube aviation kerosene dimensionless wall distance viscous length scale

Equipartition of current in metallic armchair nanoribbon of graphene-based device

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Frontiers of physics 2022年第6期17卷 63-69页

作者： Hui Yang Junjie zeng Sanyi You yulei Han Zhenhua qiao CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics and Department of PhysicsUniversity of Science and Technology of ChinaHefei 230026China Department of Physics Fuzhou UniversityFuzhou 350108China ICQD Hefei National Research Center for Physical Sciences at the MicroscaleUniversity of Science and Technology of ChinaHefei 230026China

We numerically investigate the mesoscopic electronic transport properties of Bernal-stacked bilayer/trilayer graphene connected with four monolayer graphene *** armchair-terminated metallic bilayer graphene,we show that the current from one incoming terminal can be equally partitioned into other three outgoing terminals near the charge-neutrality point,and the conductance periodically fluctuates,which is independent of the ribbon width but influenced by the interlayer hopping *** finding can be clearly understood by using the wave function matching method,in which a quantitative relationship between the periodicity,Fermi energy,and interlayer hopping energy can be ***,for the trilayer case,when the Fermi energy is located around the charge-neutrality point,the fractional quantized conductance 1/(4e 2h)can be achieved when system exceeds a critical length.

关键词： graphene electronic transport armchair nanoribbon

Modular Verification of SPARCv8 Code

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Journal of Computer Science & Technology 2020年第6期35卷 1382-1405页

作者： Jun-Peng Zha Xin-yu Feng Lei qiao Department of Computer Science and Technology Nanjing UniversityNanjing 210023China State Key Laboratory for Novel Software Technology Nanjing UniversityNanjing 210023China Beijing Institute of Control Engineering Beijing 100080China

Inline assembly code is common in system software to interact with the underlying hardware platforms. The safety and correctness of the assembly code is crucial to guarantee the safety of the whole system. In this paper, we propose a practical Hoare-style program logic for verifying SPARC (Scalable Processor Architecture) assembly code. The logic supports modular reasoning about the main features of SPARCv8 ISA (instruction set architecture), including delayed control transfers, delayed writes to special registers, and register windows. It also supports relational reasoning for refinement verification. We have applied it to verify that there is a contextual refinement between a context switch routine in SPARCv8 and a switch primitive. The program logic and its soundness proof have been mechanized in Coq.

关键词： Scalable Processor Architecture Version 8(SPARCv8) assembly code verification context switch Coq refinement verification

Formation of topological domain walls and quantum transport properties of zero-line modes in commensurate bilayer graphene systems

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Frontiers of physics 2022年第6期17卷 95-105页

作者： Junjie zeng Rui Xue Tao Hou yulei Han Zhenhua qiao ICQD Hefei National Laboratory for Physical Sciences at MicroscaleCAS Key Laboratory of Strongly-Coupled Quantum Matter PhysicsDepartment of PhysicsUniversity of Science and Technology of ChinaHefei 230026China Department of Physics Fuzhou UniversityFuzhou 350108China

We study theoretically the construction of topological conducting domain walls with a finite width between AB/BA stacking regions via finite element method in bilayer graphene systems with tunable commensurate twisting *** find that the smaller is the twisting angle,the more significant the lattice reconstruction would be,so that sharper domain boundaries declare their *** subsequently study the quantum transport properties of topological zero-line modes which can exist because of the said domain boundaries via Green’s function method and Landauer–Büttiker formalism,and find that in scattering regions with triintersectional conducting channels,topological zero-line modes both exhibit robust behavior exemplified as the saturated total transmission Gtot≈2e_(2)/h and obey a specific pseudospin-conserving current partition law among the branch transport *** former property is unaffected by Aharonov–Bohm effect due to a weak perpendicular magnetic field,but the latter is *** from our genuine bilayer hexagonal system suggest a twisting angle aroundθ≈0.1°for those properties to be expected,consistent with the existing experimental reports.

关键词： twistronics lattice reconstruction topological domain wall zero-line mode quantum transport