检索结果-南通市图书馆

Pseudoconformal equation of state in compact-star matter from topology change and hidden symmetries of QCD

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2019年第11期62卷 87-92页

作者： Yong-Liang Ma Hyun Kyu Lee Won-Gi Paeng Mannque Rho Center for Theoretical Physics and College of Physics Jilin UniversityChangchun 130012China Department of Physics Hanyang UniversitySeoul 133-791Korea Rare Isotope Science Project Institute for Basic ScienceDaejeon 305-811Korea Institut de Physique Theorique CEA Saclay91191 Gif-sur-Yvette cedexFrance

We construct a new effective field theory approach to the equation of state(EoS), dubbed pseudo-confomal model 'PCM', for nuclear and compact star matter entirely in terms of effective hadron degrees of freedom. The possible transition at n ^(2-4)n0(where n0 is the normal nuclear matter density) from hadron degrees of freedom to strongly-coupled quark degrees of freedom,giving rise to a soft-to-hard changeover in the EoS that can accommodate the massive stars observed, is effectuated by the topology change at n1/2>~ 2n0 from skyrmions to half-skyrmions without involving local order-parameter fields. The mechanism exploits possible emergence of hidden scale and local symmetries of QCD at high density, leading to a precocious 'pseudo-conformal'sound velocity vs2= 1/3(in unit of c = 1) for n>~ 3n0. The resulting prediction signals a drastic departure from standard nuclear many-body theory in the density regime involved in the massive stars. We suggest that the tidal deformability implemented in gravitational waves coming from coalescing neutron stars in LIGO/Virgo-type observations could pin down the location of the topology change density n1/2.

关键词： equation of state compact star tidal deformability conformal sound velocity

state of rare earth elements in the rare earth deposits of Northwest Guizhou,China

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2018年第6期37卷 867-874页

作者： Peinan He Mingyou He Hai Zhang College of Air Traffic Management Civil Aviation Flight University of ChinaGuanghan618307China Chengdu University of Technology Chengdu610059China 113 Geological Team Bureau of Geology and Mineral ResourcesLiupanshui553001GuizhouChina

We studied the states of rare earth elements in ore of the Xianglushan rare earth deposit. Rare earth ore samples were tested and examined by scanning electron microscope, electron probe, and chemical leaching. No independent rare earth minerals were detected by scanning electron microscope. Elements detected by the electronic probe for the in situ micro-zone of the sample included: O,Al, Si, Ca, Mg, Fe, Ti, K, Na, S, Cl, C, Cu, Cr, V, and *** earth elements were not detected by electron probe.(NH_4)_2 SO_4,(NH_4)Cl, NaCl, and H_2 SO_4 were used as reagents in chemical leaching experiments that easily leached out rare earth elements under the action of 10%reagent, indicating that the rare earth elements in ore are mainly in the ionic state rather than present as rare earth minerals.

关键词： Kaolinite Clay rocks Rare earth deposits Element existence state Information extraction Northwest Guizhou Province

Controlling the magnetic state of the proximate quantum spin liquid α-RuCl_(3) with an optical cavity

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2023年第1期9卷 265-274页

作者： Emil Viñas Boström Adithya Sriram Martin Claassen Angel Rubio Max Planck Institute for the Structure and Dynamics of Matter Luruper Chaussee 14922761 HamburgGermany Department of Physics Stanford UniversityStanfordCA 94305USA Department of Physics and Astronomy University of PennsylvaniaPhiladelphiaPA 19104USA Center for Computational Quantum Physics Flatiron InstituteSimons FoundationNew York CityNY 10010USA

Harnessing the enhanced light-matter coupling and quantum vacuum fluctuations resulting from mode volume compression in optical cavities is a promising route towards functionalizing quantum materials and realizing exotic states of ***,we extend cavity quantum electrodynamical materials engineering to correlated magnetic systems,by demonstrating that a Fabry-Pérot cavity can be used to control the magnetic state of the proximate quantum spin liquidα-RuCl_(3).Depending on specific cavity properties such as the mode frequency,photon occupation,and strength of the light-matter coupling,any of the magnetic phases supported by the extended Kitaev model can be *** particular,in the THz regime,we show that the cavity vacuum fluctuations alone are sufficient to bringα-RuCl_(3) from a zigzag antiferromagnetic to a ferromagnetic *** external pumping of the cavity in the few photon limit,it is further possible to push the system into the antiferromagnetic Kitaev quantum spin liquid state.

关键词： state quantum magnetic

state vector solutions for nonaxisymmetric problem of multilayered half space piezoelectric medium

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 1999年第12期42卷 1323-1331页

作者：王建国 1. Department of Civil Engineering Hefei University of Technology 230009 Hefei China

A state space formulation is established for the nonaxisymmetric space problem of transversely isotropic piezoelectric media in a system of cylindrical coordinate by introducing the state vector. Using the Hankel transform and the Fourier series, the state vector equations are transformed into ordinary differential equations. By the use of the matrix methods, the analytical solutions of a single piezoelectric layer are presented in the form of the product of initial state variables and transfer matrix. The applications of state vector solutions are discussed. An analytical solution for a semiinfinite piezoelectric medium subjected to the vertical point force P_z, horizontal point force P_x along x-direction and point electric charge Q at the origin of the surface is presented. According to the continuity conditions at the interfaces, the general solution formulation for N-layered transversely isotropic piezoelectric media is given.

关键词： multilayered piezoelectric media transverse isotropy nonaxisymmetric problems state vector equations transfer matrix analytical solutions.

Parameter identification and state-of-charge estimation approach for enhanced lithium–ion battery equivalent circuit model considering influence of ambient temperatures

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第10期28卷 562-570页

作者： Hui Pang Lian-Jing Mou Long Guo School of Mechanical and Precision Instrument Engineering Xi’an University of Technology

It is widely accepted that the variation of ambient temperature has great influence on the battery model parameters and state-of-charge(SOC) estimation, and the accurate SOC estimation is a significant issue for developing the battery management system in electric vehicles. To address this problem, in this paper we propose an enhanced equivalent circuit model(ECM) considering the influence of different ambient temperatures on the open-circuit voltage for a lithium-ion battery. Based on this model, the exponential-function fitting method is adopted to identify the battery parameters according to the test data collected from the experimental platform. And then, the extended Kalman filter(EKF) algorithm is employed to estimate the battery SOC of this battery ECM. The performance of the proposed ECM is verified by using the test profiles of hybrid pulse power characterization(HPPC) and the standard US06 driving cycles(US06) at various ambient temperatures, and by comparing with the common ECM with a second-order resistance capacitor. The simulation and experimental results show that the enhanced battery ECM can improve the battery SOC estimation accuracy under different operating conditions.

关键词： lithium-ion battery parameter identification state of charge ambient temperature

EQUATION OF state BASED HYDRATE MODEL FOR NATURAL GAS SYSTEMS CONTAINING BRINE AND POLAR INHIBITOR

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 1996年第3期4卷 4-17页

作者：左有祥郭天民 Sφren Gommesen Visiting MS student from the Technical University of Denmark

A new thermodynamic model for gas hydrates was established by combining the modified Patel-Teja equation of state proposed for aqueous electrolyte systems and the simplified Holder -John multi -shell hydrate model. The new hydrate model is capable of predicting the hydrate formation/dissociation conditions of natural gas systems containing pure water/formation water (brine) and polar inhibitor without using activity coefficient model. Extensive test results indicate very encouraging results.

关键词： hydrate model equation of state brine natural gas

Comparative Study on Solid-state and Metastable Liquid-state Aging for SAC305/Cu Joints

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2019年第5期32卷 629-637页

作者： Shuang Li Xiao-Wu Hu Wei-Guo Zhang Yu-Long Li Xiong-Xin Jiang Key Lab for Robot and Welding Automation of Jiangxi Province Mechanical and Electrical Engineering SchoolNanchang University College of Mechanical and Electronic Engineering Northwest A&F University

In order to study the in?uence of the physical state of solder on the interfacial reaction of dip-soldered Sn-3.0 Ag-0.5 Cu/Cu system, two kinds of experiments were designed, including:(1) solid-state aging between the solder and Cu substrate;(2)liquid-state aging between the metastable supercooled liquid-state solder and Cu substrate. The aging times were 30, 60,120 and 180 min, respectively, and the aging temperature was 8 ℃ lower than the melting point of the Sn-3.0 Ag-0.5 Cu(SAC305) alloy(217 ℃). The experimental data revealed that the physical state of the solder obviously affected the formation of the intermetallic compound(IMC), and resulted in the difference in the diffusion of atoms on the interface between the SAC305 solder and Cu substrate. The IMC interface after aging for 30 min presents unique characteristics compared with that of the sample after dip soldering. The IMC interface of solid-state aged SAC305/Cu couple is relatively planar, while the IMC interface under metastable supercooled liquid-state aging conditions presents scallop-like shape.

关键词： Lead-free solder Supercooling Metastable liquid state Aging Intermetallic compound

Remaining Useful Life Model and Assessment of Mechanical Products: A Brief Review and a Note on the state Space Model Method

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2019年第1期32卷 11-30页

作者： Yawei Hu Shujie Liu Huitian Lu Hongchao Zhang School of Mechanical Engineering Dalian University of Technology Department of Construction & Operations Management South Dakota State University Department of Industrial Engineering Texas Tech University

The remaining useful life(RUL) prediction of mechanical products has been widely studied for online system performance reliability, device remanufacturing, and product safety(safety awareness and safety improvement). These studies incorporated many di erent models, algorithms, and techniques for modeling and assessment. In this paper, methods of RUL assessment are summarized and expounded upon using two major methods: physics model based and data driven based methods. The advantages and disadvantages of each of these methods are deliberated and compared as well. Due to the intricacy of failure mechanism in system, and di culty in physics degradation observation, RUL assessment based on observations of performance variables turns into a science in evaluating the degradation. A modeling method from control systems, the state space model(SSM), as a first order hidden Markov, is presented. In the context of non-linear and non-Gaussian systems, the SSM methodology is capable of performing remaining life assessment by using Bayesian estimation(sequential Monte Carlo). Being e ective for non-linear and non-Gaussian dynamics, the methodology can perform the assessment recursively online for applications in CBM(condition based maintenance), PHM(prognostics and health management), remanufacturing, and system performance reliability. Finally, the discussion raises concerns regarding online sensing data for SSM modeling and assessment of RUL.

关键词： Remaining useful life state space model Online assessment Bayesian estimation Particle filter Remanufacturing

Dissipative generation for steady-state entanglement of two transmons in circuit QED

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第8期28卷 50-55页

作者： Shuang He Dan Liu Ming-Hao Li Department of Nuclear Medicine Yanbian University Hospital

We present a dissipative scheme to generate an entangled steady-state between two superconducting transmon qutrits separately embedded in two coupled transmission line resonators in a circuit quantum electrodynamics(QED)*** our scheme,the resonant qutrit-resonator interaction and photon hopping between resonators jointly induce asymmetric energy gaps in the dressed state *** coherent driving fields induce the specific dressed state transition and the dissipative processes lead to the gradual accumulation in the population of target state,combination of both drives the system into a steady-state *** simulation shows that the maximally entangled state can be produced with high fidelity and strong robustness against the cavity decay and qutrit decay,and no requirements for accurate time *** scheme is achievable with the current experimental technologies.

关键词： steady-state entanglement dissipation dressed state