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From Elastic Spin to Phonon Spin:Symmetry and Fundamental Relations

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Chinese Physics Letters 2022年第12期39卷 41-49页

作者： jie ren Center for Phononics and Thermal Energy Science China-EU Joint Lab on NanophononicsShanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai 200092China

This work is mainly based on postgraduate lectures at Tongji University since 2020 *** firstly revisit the elastic spin and orbital angular momentum[*** 115,9951(2018)]but more general for anisotropic systems by applying Noether’s theorem to the elastic Lagrangian and by applying the symmetry argument in the field ***,fundamental relations between elastic energy flux and elastic spin are *** particular cases,the wave spin is closely related to the vorticity of energy flux and ***,we move forward from the elastic spin to revisit the phonon spin[Fizika Tverdogo Tela 3,2160(1961)]by applying the second quantization to elastic *** show that the uncovered phonon spin,a polarized elastic-vibration quanta,is generally not restricted to transverse phonon modes,but applying to general phonon modes,such as the longitudinal phonon modes,surface phonon modes,and hybridized phonon modes,regarded as a consequence of mode *** elastic spin and phonon spin originate from the local rotating of the field polarization in time domain,not the local circulation(vorticity)of displacement or velocity in space *** is hopeful that the present results could advance the fundamental understanding of phonon spin and elastic spin,and promote the spin phononics for hybrid quantum sensing and technology with multiple degrees of freedom.

关键词： theory phonon applying

Detectable states, cycle fluxes, and motility scaling of molecular motor kinesin： An integrative kinetic graph theory analysis

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Frontiers of physics 2017年第6期12卷 21-32页

作者： jie ren Center for Phononics and Thermal Energy Science School of Physics Science and Engineering Tongji University 200092 Shanghai China

The process by which a kinesin motor couples its ATPase activity with concerted mechanical hand- over-hand steps is a foremost topic of molecular motor physics. Two major routes toward elucidating kinesin mechanisms are the motility performance characterization of velocity and run length, and single-molecular state detection experiments. However, these two sets of experimental approaches are largely uncoupled to date. Here, we introduce an integrative motility state analysis based on a theorized kinetic graph theory for kinesin, which, on one hand, is validated by a wealth of accumulated motility data, and, on the other hand, allows for rigorous quantification of state occurrences and chemomechanical cycling probabilities. An interesting linear scaling for kincsin motility performance across species is discussed as well. An integrative kinetic graph theory analysis provides a powerful tool to bridge motility and state characterization experiments, so as to forge a unified effort for the elucidation of the working mechanisms of molecular motors.

关键词： graph theory molecular motor state detection cycle flux motility scaling

Floquet analysis of fundamental,subharmonic and detuned secondary instabilities of Grtler vortices

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Science China(Physics,Mechanics & Astronomy) 2014年第3期57卷 555-561页

作者： ren jie FU Song School of Aerospace Engineering Tsinghua University

Nonlinear parabolized stability equations are employed in this work to investigate the nonlinear development of the G6rtler insta- bility up to the saturation stage. The perturbed boundary layer is highly inflectional both in the normalwise and spanwise directions and receptive to the secondary instabilities. The Floquet theory is applied to solve the fundamental, subharmonic and detuned secondary instabilities. With the Gortler-vortices-distorted base flow, two classes of secondary disturbances, i.e. odd modes and even modes, are identified according to the eigenfunctions of the disturbances. These modes may result in different patterns in the late stages of the transition process. Li and Malik [ 1 ] have shown the sinuous and varicose types of breakdown originating from the odd and even modes. The current study focuses on the four most amplified modes termed the even modes I ＆ Ⅱ and odd modes I ＆ lI. Odd mode II was missing in the work of Li and Malik [1] probably due to their inviscid simplifeation. The detuned modes are confirmed to be less amplifed than the fundamental （for the odd mode I） and subharmonic modes （for even modes I ＆ II and the odd mode II）.

关键词： Goirtler vortices secondary instability Floquet theory

Competition of the multiple Grtler modes in hypersonic boundary layer flows

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Science China(Physics,Mechanics & Astronomy) 2014年第6期57卷 1178-1193页

作者： ren jie FU Song School of Aerospace Engineering Tsinghua University

Competition of multiple Gortler modes in hypersonic boundary layer flows are investigated with the local and marching methods. The wall-layer mode （mode W） and the trapped-layer mode （mode T） both occur in the compressible boundary layer where there exists a temperature adjustment layer near the upper edge. The mode T has the largest growth rate at a lower Gortler number while the mode W dominates at larger G/Srtler numbers. These two modes are both responsible for the flow transition in the hypersonic flows especially when Gortler number is in the high value range in which the crossover of these two modes takes place. Such high Gortler numbers are virtually far beyond the neutral regime. The nonparallel base flows, therefore, cease to influence the stability behavior of the Gortler modes. The effects of the Mach number on the multiple Gortler modes are studied within a chosen Mach number of 0.95, 2, 4 and 6. When the flow Mach number is sufficiently large, e.g., Ma ≥4, the growth rate crossover of the mode T and mode W occurs both in the conventional G-β map as well as on the route downstream for a fixed wavelength disturbance. Four particular regions （Region T, T-W, W-T and W） around the crossover point are highlighted with the marching analysis and the result matches that of the local analysis. The initial disturbance of a normal mode maintains the shape in its corresponding dominating region while a shape-transformation occurs outside this region.

关键词： Gortler vortices linear stability theory multiple modes local analysis marching analysis

WALL EFFECTS ON FLOWS PAST TWO TANDEM CYLINDERS OF DIFFErenT DIAMETERS

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Journal of Hydrodynamics 2012年第1期24卷 1-10页

作者： JIANG ren-jie LIN Jian-zhong State Key Laboratory of Fluid Power Transmission and Control Zhejiang UniversityHangzhou 310027China China Jiliang University Hangzhou 310018China

Flows past two tandem cylinders of different diameters placed centrally in a channel with fixed centre-to-centre spacing 6D and diameter ratio are simulated based on the Lattice Boltzmann Method（LBM）.In all the simulations,the diameter of the smaller cylinder is chosen as the characteristic *** Reynolds number based on the average inflow velocity is 20-120 and studies are over the range of blockage ratio *** both Small-Big Arrangement（SBA）and Big-Small Arrangement（BSA）,the effects of the channel width and Reynolds number on the flow structures and force coefficients are *** show that the flows in BSA are more regular than those in SBA for the same flow *** BSA with and,the force coefficients all fluctuate with constant amplitudes and a coupled frequency,the coupled frequency becomes small as the blockage ratio decreases and by an exact test we give out the relation of the blockage ratio and Strouhal *** the blockage ratio decreases to 2,there exist pitchfork bifurcations in both SBA and BSA,and results show that the critical Reynolds numbers of pitchfork bifurcations for SBA and BSA are both between 60 and *** SBA with,the flow structure has a static asymmetric *** is found that the channel width has also an effect on the critical spacing where the flow changes from single body mode into co-shedding *** an accurate survey on flows past two cylinders with equal diameters placed inside a channel with the width,the relation between channel width and the critical spacing is given and results show that the critical spacing increases as the channel width increases.

关键词： two tandem cylinders different diameters blockage ratio critical spacing Lattice Boltzmann Method(LBM)

Mn、Zn、Sn掺杂CsPbI_(3)的稳定性和光电性质研究

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原子与分子物理学报 2025年第2期42卷 182-188页

作者：张仁杰陶红帅郝启圣内蒙古工业大学理学院呼和浩特010051

采用基于密度泛函理论的第一性原理,计算了本征CsPbI_(3)和Mn、Zn、Sn掺杂体系的形成能、电子结构和光学性质.研究结果表明:Mn、Zn、Sn的掺入减小了材料晶格常数,Mn原子掺入CsPbI_(3)晶体结构使得体系的磁矩由0变为5.00μ_(B),丰富了材... 详细信息

采用基于密度泛函理论的第一性原理,计算了本征CsPbI_(3)和Mn、Zn、Sn掺杂体系的形成能、电子结构和光学性质.研究结果表明:Mn、Zn、Sn的掺入减小了材料晶格常数,Mn原子掺入CsPbI_(3)晶体结构使得体系的磁矩由0变为5.00μ_(B),丰富了材料磁性.与Zn掺杂体系相比,Mn、Sn掺杂体系更为稳定.Mn掺杂体系增大了材料带隙,Zn、Sn的掺入使材料带隙分别减小了30.2%和16.2%,有利于电子极化跃迁,但Zn掺入使CsPbI_(3)材料转变为间接带隙半导体.在可见光区域中Mn、Zn、Sn掺杂体均表现出优异的光学性能,Sn掺杂体系效果最佳.这些研究结果为实验方面CsPbI_(3)材料的掺杂改性提供了数据支持,有利于CsPbI_(3)钙钛矿在光电领域的应用.

关键词： CsPbI_(3) 第一性原理电子结构光学性质

Geometric Thermoelectric Pump:Energy Harvesting beyond Seebeck and Pyroelectric Effects

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Chinese Physics Letters 2023年第9期40卷 7-13页

作者：任捷 Center for Phononics and Thermal Energy Science China-EU Joint Lab on NanophononicsShanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai 200092China

Thermal-electric conversion is crucial for smart energy control and harvesting,such as thermal sensing and waste heat *** far,researchers are aware of two main ways of direct thermal-electric conversion,Seebeck and pyroelectric effects,each with different working mechanisms,conditions and ***,we report the concept of Geometric Thermoelectric Pump(GTEP),as the third way of thermal-electric conversion beyond Seebeck and pyroelectric *** contrast to Seebeck effect that requires spatial temperature difference,GTEP converts the time-dependent ambient temperature fluctuation into ***,GTEP does not require polar materials but applies to general conducting systems,and thus is also distinct from pyroelectric *** demonstrate that GTEP results from the temperature-fluctuation-induced charge redistribution,which has a deep connection to the topological geometric phase in non-Hermitian dynamics,as a consequence of the fundamental nonequilibrium thermodynamic *** findings advance our understanding of geometric phase induced multiple-physics-coupled pump effect and provide new means of thermal-electric energy harvesting.

关键词： Seebeck harvesting geometric

Bipartite and Tripartite Entanglement in a Three-Qubit Heisenberg Model

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Communications in Theoretical Physics 2006年第6X期46卷 969-974页

作者： ren jie ZHU Shi-Qunt School of Physical Science and Technology Suzhou University Suzhou 215006 China

The bipartite and tripartite entanglement in a three-qubit Heisenberg XY model with a nonuniform magnetic field is studied. There are two or four peaks in the concurrence of the bipartite entanglement when the amplitudes of the magnetic fields are. differently distributed between the three qubits. It is very interesting to note that there is no tangle of tripartite entanglement between the three qubits when the amplitudes of the magnetic fieMs are varied. However, the variation of the magnetic field direction can induce the tangle. The tangle is periodic about the angle between the magnetic field and the z axis of the spin.

关键词： bipartite entanglement tripartite entanglement Heisenberg XY model

Theoretical Study of Decomposition Pathways for Rare-gas-containing Compounds HRgX (Rg = He, Ne, Ar, Kr; X = Cl, Br)

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Chinese Journal of Structural Chemistry 2005年第12期24卷 1445-1451页

作者： AI Chun-Zhi SUN ren-An YAN jie College of Chemistry and Chemical Engineering Liaoning normal university Dalian 116029 China

Eight species, HRgX （Rg = He, Ne, Ar, Kr; X = Cl, Br）, are predicted to have bending transition states at B3PW91/AUG-cc-PVTZ level, leading to 2-body decomposition pathway like H-Rg-X→Rg＋HX. The reaction path has been obtained with Intricate Reaction Coordinates （IRC） method on identical theoretical level. Additionally, the linear transition states of HArCl, HArBr, HKrCl and HKrBr were obtained at MP2/6-311 ＋＋G （2d, 2p） level, resulting in 3-body dissociation channel as H-Rg-X→H ＋ Rg＋ X.

关键词： decomposition pathway transition state IRC energy barrier