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Abstract models for heat engines

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Frontiers of physics 2021年第3期16卷 99-110页

作者： Zhan-chun.tu Department of Physics Beijing Normal UniversityBeijing100875China

We retrospect three abstract models for heat engines which include a classic abstract model in textbook of thermal physics,a primary abstract model for finite-time heat engines,and a refined abstract model for finite-time heat *** detailed models of heat engines in literature of finite-time thermodynamics may be mapped into the refined abstract *** future developments based on the refined abstract model are also surveyed.

关键词： abstract model heat engine finite-time thermodynamics

Responses of greenhouse gas fluxes to experimental warming in wheat season under conventional tillage and no-tillage fields

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Journal of Environmental Sciences 2017年第4期29卷 314-327页

作者： chun.tu Fadong Li Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences University of Chinese Academy of Sciences College of Resources and Environment University of Chinese Academy of Sciences

Understanding the effects of warming on greenhouse gas（GHG, such as N2O, CH4 and CO2 ）feedbacks to climate change represents the major environmental issue. However, little information is available on how warming effects on GHG fluxes in farmland of North China Plain（NCP）. An infrared warming simulation experiment was used to assess the responses of N2O, CH4 and CO2 to warming in wheat season of 2012–2014 from conventional tillage（CT） and no-tillage（NT） systems. The results showed that warming increased cumulative N2O emission by 7.7% in CT but decreased it by 9.7% in NT fields（p 〈 0.05）. Cumulative CH4 uptake and CO2 emission were increased by 28.7%–51.7% and 6.3%–15.9% in both two tillage systems,respectively（p 〈 0.05）. The stepwise regressions relationship between GHG fluxes and soil temperature and soil moisture indicated that the supply soil moisture due to irrigation and precipitation would enhance the positive warming effects on GHG fluxes in two wheat ***, in 2013, the long-term drought stress due to infrared warming and less precipitation decreased N2O and CO2 emission in warmed treatments. In contrast, warming during this time increased CH4 emission from deep soil depth. Across two years wheat seasons, warming significantly decreased by 30.3% and 63.9% sustained-flux global warming potential（SGWP） of N2O and CH4 expressed as CO2 equivalent in CT and NT fields, respectively. However, increase in soil CO2 emission indicated that future warming projection might provide positive feedback between soil C release and global warming in NCP.

关键词： Climate warming Greenhouse gas fluxes(N2O CH4 CO2) Conventional tillage No-tillage Soil temperature Soil moisture

Characterization and reactivity of biogenic manganese oxides for ciprofloxacin oxidation

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Journal of Environmental Sciences 2014年第5期26卷 1154-1161页

作者： Jinjun tu Zhendong Yang chun Hu Jiuhui Qu State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesResearch Center for Eco-Environmental Sciences

Biogenic manganese oxides （BioMnOx） were synthesized by the oxidation of Mn（II） with Mn- oxidizing bacteria Pseudomonas sp. G7 under different initial pH values and Mn（II） dosages, and were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and UV-Vis absorption spectroscopy. The crystal structure and Mn oxidation states of BioMnOx depended on the initial pH and Mn（lI） dosages of the medium. The superoxide radical （O2） was observed in Mn-containing （III/IV） BioMnOx suspensions by electron spin resonance measurements. BioMnOx（0.4）-7, with mixed valence of Mn（II/III/IV） and the strongest O^- signals, was prepared in the initial pH 7 and Mn（II） dosage of 0.4 mmol/L condition, and exhibited the highest activity for ciproftoxacin degradation and no Mn（II） release. During the degradation of ciprofloxacin, the oxidation of the Mn（II） formed came from biotic and abiotic reactions in BioMnOx suspensions on the basis of the Mn（II） release and O2- formation from different BioMnOx. The degradation process of ciprofloxacin was shown to involve the cleavage of the hexatomic ring having a secondary amine and carbon-carbon double bond connected to a carboxyl group, producing several compounds containing amine groups as well as small organic acids.

关键词： Mn oxidation state Mn-oxidizing bacteria superoxide radicals ciprofloxacin degradation

A Possible Generalized Form of Jarzynski Equality

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Communications in Theoretical Physics 2006年第5X期46卷 886-890页

作者： tu Zhan-chun ZHOU Zi-Cong Department of Physics Tamkang University Tamsui 25137 Taiwan China Physics Division National Center for Theoretical Sciences at Taipei National Taiwan University Taipei 10617 Taiwan China

The crucial condition in the derivation of the Jarzynski equality （JE） from the fluctuation theorem is that the time integral of the phase space contraction factor can be exactly expressed as the entropy production resulting from the heat absorbed by the system from the thermal bath. For the system violating this condition, a more general form of JE may exist. This existence is verified by three Gedanken experiments and numerical simulations, and may be confirmed by the real experiment in the nanoscale.

关键词： Jarzynski equality fluctuation theorem entropy production

Morphologies of Al_4Sr Intermetallic Phase and Its Modification Property upon A356 Alloys

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Journal of Materials Science & Technology 2012年第6期28卷 524-530页

作者： Chengwei Liao Jianchun chun Yang Li Rui tu chunxu Pan School of Physics and Technology and Center for Electron Microscopy Wuhan UniversityWuhan 430072China Hunan Jinlianxing Specially Materials Technology Co.Ltd Yueyang 414005China

In general, the modification performance of AI-Sr master alloys is primarily dependent upon the morphologies and sizes of the AI4Sr intermetallic phase. In this paper, the crystal structure, morphologies, sizes, hardness and elastic modulus of AI4Sr in AI-Sr master alloys prepared from variant processes were studied by means of optical metallurgical microscope, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and nanoindentation system. The results revealed that the microstructures and modification performance of the AI4Sr phase were related to the preparation processes. That is to say, when a ＂direct reaction-hot extrusion＂ process was used, the AI4Sr phase exhibited a homogeneous distribution in the AI matrix with small size and roundish shapes, which ensured the AI-Sr master alloy wire advantages involving high recovery, good reproducibility, no delitescence of modification, no corrosion on equipments, and good workability. However, in the case of the traditional ＂direct reaction＂ process, the AI4Sr phase was in large size with shapes of rectangular stripe and plates, which limited the Sr content increasing due to the brittleness of the AI-Sr alloy. It was also found that the morphology and size of the AI4Sr phases changed during heat treatment at high temperature up to 600℃.

关键词： Intermetallics Modification Hot extrusion Heat treatment Microstructure

First integrals of the axisymmetric shape equation of lipid membranes

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Chinese Physics B 2018年第3期27卷 551-559页

作者： Yi-Heng Zhang Zachary McDargh Zhan-chun.tu Department of Physics Beijing Normal UniversityBeijing 100875China Department of Physics Carnegie Mellon University5000 Forbes AvenuePittsburgh PA 15213USA

The shape equation of lipid membranes is a fourth-order partial differential *** the axisymmetric condi-tion,this equation was transformed into a second-order ordinary differential equation(ODE)by Zheng and Liu(***.E 482856(1993)).Here we try to further reduce this second-order ODE to a first-order ***,we invert the usual process of variational calculus,that is,we construct a Lagrangian for which the ODE is the corresponding Euler-Lagrange ***,we seek symmetries of this Lagrangian according to the Noether *** a certain restriction on Lie groups of the shape equation,we find that the first integral only exists when the shape equation is identical to the Will-more equation,in which case the symmetry leading to the first integral is scale *** also obtain the mechanical interpretation of the first integral by using the membrane stress tensor.

关键词： lipid membrane shape equation first integral Noether theorem

A single-point measurement scheme for quantum work based on the squeezing state

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Communications in Theoretical Physics 2021年第6期73卷 51-58页

作者： Bao-Ming Xu Jian Zou Zhan-chun.tu Shandong Key Laboratory of Biophysics Institute of BiophysicsDezhou UniversityDezhou 253023China School of Physics Beijing Institute of TechnologyBeijing 100081China Department of Physics Beijing Normal UniversityBeijing 100875China

To investigate the role of initial quantum coherence in work-probability distribution,it is necessary to consider an incomplete or partial measurement,in which the energy cannot be fully discriminated by the *** this paper,we use a harmonic oscillator with a coherent or squeezing state to realize this incomplete or partial measurement,and propose a unified framework of quantum work statistics for a closed system with an arbitrary initial *** find that work is proportional to the change of the real part of the coherent state parameter,i.e.,quantum work can be estimated by the coherent state *** resulting work-probability distribution includes the initial quantum coherence,and can be reduced to the result of the traditional two projective energy measurement scheme(TPM)by squeezing the state of the harmonic *** measurement scheme reveals the fundamental connections between measurement error and coherent *** introducing a‘coherent work-to-noise ratio’,we find the optimal measurement error,which is determined by the energy difference between the superposed energy *** an application,we consider a driven two-level system and investigate the effects of driving velocity on work *** find that only when the driving velocity matches the transition frequency of the system can initial quantum coherence play an important role.

关键词： work distribution quantum coherence coherent state squeezing state

Percutaneous coronary intervention for acute myocardial infarction with mitral regurgitation

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Journal of Geriatric Cardiology 2016年第6期13卷 521-527页

作者： Yan tu Qing-chun ZENG Ying HUANG Jian-Yong LI Department of Cardiology Nanfang Hospital Southern Medical University Gunaghzou China

Ischemic mitral regurgitation （IMR） is a common complication of acute myocardial infarction （AMI）. Current evidences suggest that revascularization of the culprit vessels with percutaneous coronary artery intervention （PCI） or coronary artery bypass grafting can be beneficial for relieving IMR. A 2.5-year follow-up data of a 61-year-old male patient with ST-segment elevation AMI complicated with IMR showed that mitral regurgitation area increased five days after PCI, and decreased to lower steady level three months after PCI. This finding suggest that three months after PCI might be a suitable time point for evaluating the possibility oflMR recovery and the necessity of surgical intervention of the mitral valve for AMI patient.

关键词： Acute myocardial infarction Follow-up Mitral regurgitation

Quasistatic Magnetic Field Generation by an Intense Ultrashort Laser Pulse in Underdense Plasma

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Chinese Physics Letters 2000年第10期17卷 746-748页

作者： ZHENG chun-Yang ZHU Shao-ping HE Xian-tu Institute of Applied Physics and Computational Mathematics P.O.Box 8009Beijing 100088

The quasistatic magnetic field created in the interaction of intense ultrashort laser pulses with underdense plasmas has been investigated by two-dimensional particle *** relativistic ponderomotive force and plasma wave excited in self-modulation processes can drive intense electron current mainly in the propagation *** a result,an azimuthal,multi-mega Gauss order quasi-static magnetic field can be generated around the laserbeam.

关键词： ultrashort intense Pulse