检索结果-南通市图书馆

An effective gauge field theory of the nucleon interactions

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

Communications in Theoretical Physics 2024年第10期76卷 76-84页

作者： eduard Boos Skobeltsyn Institute of Nuclear Physics Lomonosov Moscow State UniversityLeninskie Gory119991MoscowRussia Faculty of Physics Lomonosov Moscow State UniversityLeninskie Gory119991MoscowRussia

We discuss the possibility of constructing an effective gauge field theory of the nucleon interactions based on the ideas of isotopic invariance as well as hypercharge invariance as a local gauge symmetry and spontaneous breaking of this symmetry. The constructed effective field theory predicts the structure of interactions of protons and neutrons with ρ- and σ-mesons, and with pi-mesons and photons, as well as interactions of these particles with each other. The Lagrangian of the theory consists of several parts involving dimension 4 and 5 gauge invariant operators. Feynman rules for physical degrees of freedom that follow on from the Lagrangian define the structure of diagrams for one-boson exchanges between nucleons, predicting the internucleon one-boson-exchange potential as well as nucleon scattering amplitudes. The range of applicability of the effective theory is discussed and estimates are made of the resulting coupling constants. The theory predicts the mass of the neutral ρ^(0)-meson to be about 1 MeV larger than the mass of the charged mesons ρ^(±). The vector ω-meson, which is a sterile particle with respect to the considered gauge group SU_(I)(2) × U_(Y)(1), can be added to the scheme via a gauge-invariant operator of dimension 5, as shown in the appendix.

关键词： gauge invariance spontaneous symmetry breaking nucleon interactions

Investigation of the liquid recycle in the reactor cascade of an industrial scale ebullated bed hydrocracking unit

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2019年第2期27卷 298-304页

作者： eduard Manek Juma Haydary Institute of Chemical and Environmental Engineering Faculty of Chemical and Food Technology Slovak University of Technology

One of the commercial means to convert heavy oil residue is hydrocracking in an ebullated bed. The ebullated bed reactor includes a complex gas–liquid–solid backmixed system which attracts the attention of many scientists and research groups. This work is aimed at the calculation of the internal recycle flow rate and understanding its effect on other parameters of the ebullated bed. Measured data were collected from an industrial scale residual hydrocracking unit consisting of a cascade of three ebullated bed reactors. A simplified block model of the ebullated bed reactors was created in Aspen Plus and fed with measured data. For reaction yield calculation, a lumped kinetic model was used. The model was verified by comparing experimental and calculated distillation curves as well as the calculated and measured reactor inlet temperature. Influence of the feed rate on the recycle ratio(recycle to feed flow rate) was estimated. A relation between the recycle flow rate, pump pressure difference and catalyst inventory has been identified. The recycle ratio also affects the temperature gradient along the reactor cascade. Influence of the recycle ratio on the temperature gradient decreased with the cascade member order.

关键词： Residual hydrocracking Ebullated bed reactor Liquid recycle Aspen Plus Simulation

Exclusive meson production at HERMES

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2010年第9期34卷 1472-1475页

作者： eduard Avetisyan Deutsches Electronen Synchrotron

The exclusive electroproduction of pseudoscalar and vector mesons was studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen *** results are compared to calculations based on generalized parton distributions,some of which are sensitive to the contribution of the total angular momentum of the quarks to the proton spin.

关键词： exclusive meson production generalized parton distributions

The Investigation of the Dynamical Evolution of Extrasolar Three-planetary System GJ 3138

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2022年第1期22卷 68-84页

作者： Alexander Perminov eduard Kuznetsov Ural Federal University 51 Lenin AvenueYekaterinburgRussia

This article is devoted to studying the dynamical evolution and orbital stability of compact extrasolar threeplanetary system GJ 3138. In this system, all semimajor axes are less than 0.7 au. The modeling of planetary motion is performed using the averaged semi-analytical motion theory of the second order in planetary masses,which the authors construct. Unknown and known with errors orbital elements vary in allowable limits to obtain a set of initial conditions. Each of these initial conditions is applied for the modeling of planetary motion. The assumption about the stability of observed planetary systems allows to eliminate the initial conditions leading to excessive growth of the orbital eccentricities and inclinations and to identify those under which these orbital elements conserve moderate values over the whole modeling interval. Thus, it becomes possible to limit the range of possible values of unknown orbital elements and determine their most probable values in terms of stability.

关键词： Planetary Systems planets and satellites:dynamical evolution and stability planetstar interactions celestial mechanics

Artificial boundary conditions for Euler–Bernoulli beam equation

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2014年第5期30卷 687-692页

作者： Shao-Qiang Tang eduard G.Karpov HEDPS CAPT and LTCS College of EngineeringPeking University Department of Civil and Materials Engineering University of Illinois at ChicagoChicago IL60607 USA

In a semi-discretized Euler-Bernoulli beam equa- tion, the non-nearest neighboring interaction and large span of temporal scales for wave propagations pose challenges to the effectiveness and stability for artificial boundary treat- ments. With the discrete equation regarded as an atomic lattice with a three-atom potential, two accurate artificial boundary conditions are first derived here. Reflection co- efficient and numerical tests illustrate the capability of the proposed methods. In particular, the time history treatment gives an exact boundary condition, yet with sensitivity to nu- merical implementations. The ALEX （almost EXact） bound- ary condition is numerically more effective.

关键词： Euler-Bernoulli beam. Artificial boundary con- dition - Wave propagation

Revisiting the LQR Problem of Singular Systems

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第11期11卷 2236-2252页

作者： Komeil Nosrati Juri Belikov Aleksei Tepljakov eduard Petlenkov IEEE the Department of Computer Systems Tallinn University of Technology the Department of Software Science Tallinn University of Technology

In the development of linear quadratic regulator(LQR) algorithms, the Riccati equation approach offers two important characteristics——it is recursive and readily meets the existence condition. However, these attributes are applicable only to transformed singular systems, and the efficiency of the regulator may be undermined if constraints are violated in nonsingular versions. To address this gap, we introduce a direct approach to the LQR problem for linear singular systems, avoiding the need for any transformations and eliminating the need for regularity assumptions. To achieve this goal, we begin by formulating a quadratic cost function to derive the LQR algorithm through a penalized and weighted regression framework and then connect it to a constrained minimization problem using the Bellman's criterion. Then, we employ a dynamic programming strategy in a backward approach within a finite horizon to develop an LQR algorithm for the original system. To accomplish this, we address the stability and convergence analysis under the reachability and observability assumptions of a hypothetical system constructed by the pencil of augmented matrices and connected using the Hamiltonian diagonalization technique.

关键词： DC motor optimal control penalized weighted regression power system quadratic regulator singular system

维普期刊数据库博看期刊

Robust Stability Analysis of Smith Predictor Based Interval Fractional-Order Control Systems:A Case Study in Level Control Process

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2023年第3期10卷 762-780页

作者： Majid Ghorbani Mahsan Tavakoli-Kakhki Aleksei Tepljakov eduard Petlenkov Department of Computer Systems Tallinn University of TechnologyTallinn 12618Estonia Faculty of Electrical Engineering K.N.Toosi University of TechnologyTehran ***Iran IEEE

The robust stability study of the classic Smith predictor-based control system for uncertain fractional-order plants with interval time delays and interval coefficients is the emphasis of this *** uncertainties are a type of parametric uncertainties that cannot be avoided when modeling real-world ***,in the considered Smith predictor control structure it is supposed that the controller is a fractional-order proportional integral derivative(FOPID)*** the best of the authors'knowledge,no method has been developed until now to analyze the robust stability of a Smith predictor based fractional-order control system in the presence of the simultaneous uncertainties in gain,time-constants,and time *** three primary contributions of this study are as follows:ⅰ)a set of necessary and sufficient conditions is constructed using a graphical method to examine the robust stability of a Smith predictor-based fractionalorder control system—the proposed method explicitly determines whether or not the FOPID controller can robustly stabilize the Smith predictor-based fractional-order control system;ⅱ)an auxiliary function as a robust stability testing function is presented to reduce the computational complexity of the robust stability analysis;andⅲ)two auxiliary functions are proposed to achieve the control requirements on the disturbance rejection and the noise ***,four numerical examples and an experimental verification are presented in this study to demonstrate the efficacy and significance of the suggested technique.

关键词： Interval uncertainty FOPID controller fractional-order systems robust stability analysis smith predictor

Weak-strong uniqueness for the compressible Navier-Stokes equations with a hard-sphere pressure law

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2018年第11期61卷 2003-2016页

作者： eduard Feireisl Yong Lu Antonín Novotny Institute of Mathematics Academy of Sciences of the Czech Republic Department of Mathematics Nanjing University IMATH University of Toulon

We consider the Navier-Stokes equations with a pressure function satisfying a hard-sphere *** means the pressure,as a function of the density,becomes infinite when the density approaches a finite critical *** some structural constraints imposed on the pressure law,we show a weak-strong uniqueness principle in periodic spatial *** method is based on a modified relative entropy inequality for the *** main difficulty is that the pressure potential associated with the internal energy of the system is largely dominated by the pressure itself in the area close to the critical *** a result,several terms appearing in the relative energy inequality cannot be controlled by the total energy.

关键词： Navier-Stokes equations hard-sphere pressure weak-strong uniqueness

Do Larger and Older Individuals Occupy Better Areas in the Colony of Qinghai Toad-headed Agamas?

在线全文

学校读者我要写书评

暂无评论

Asian Herpetological Research 2023年第3期14卷 183-190页

作者： eduard GALOYAN Natalia SOPILKO Anna KOVALYEVA Yin QI A.N.Severtsov Institute of Ecology and Evolution Moscow 119071Russia Lomonosov Moscow State University Leninskie Gori 1Moscow 119991Russia Chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041SichuanChina

Group living reduces the chances of *** is also true for burrowing animals,which use burrows as refuges to escape *** in the center of a colony is the safest because it offers access to the greatest number of burrows;however,it is stressful due to frequent aggressive interactions *** predicted that larger and older animals should occupy areas of a colony with a higher density of burrows than smaller and younger *** test this prediction,we observed individually marked Qinghai toad-headed agamas(Phynocephalus vlangalii)from a single colony late in the breeding season when females were *** of burrows was the highest and distance between them the shortest in the center of the *** encounters were more frequent in the central part of the colony than on its *** found a negative correlation between body size and distance to the center of the colony for females,but not for *** was no such correlation between age of individuals and distance to the center of the *** in this species likely compete with other females and males for central burrows in the colony even after mating season *** suggest that gravid females likely compete for the dense burrows within the central part of the colony mainly due to their relatively lower sprint speed and higher probability of being caught by a predator if they are not refuged in a burrow.

关键词： burrow distribution competition group living lizards Phrynocephalus space use