6,744 research outputs found
Groundstate with Zero Eigenvalue for Generalized Sombrero-shaped Potential in -dimensional Space
Based on an iterative method for solving the goundstate of Schroedinger
equation, it is found that a kind of generalized Sombrero-shaped potentials in
N-dimensional space has groundstates with zero eigenvalue. The restrictions on
the parameters in the potential are discussed.Comment: 8 pages, 3 figure
Iterative Solutions for Low Lying Excited States of a Class of Schroedinger Equation
The convergent iterative procedure for solving the groundstate Schroedinger
equation is extended to derive the excitation energy and the wave function of
the low-lying excited states. The method is applied to the one-dimensional
quartic potential problem. The results show that the iterative solution
converges rapidly when the coupling is not too small.Comment: 14 pages, 4 figure
Plaquette order and deconfined quantum critical point in the spin-1 bilinear-biquadratic Heisenberg model on the honeycomb lattice
We have precisely determined the ground state phase diagram of the quantum
spin-1 bilinear-biquadratic Heisenberg model on the honeycomb lattice using the
tensor renormalization group method. We find that the ferromagnetic,
ferroquadrupolar, and a large part of the antiferromagnetic phases are stable
against quantum fluctuations. However, around the phase where the ground state
is antiferroquadrupolar ordered in the classical limit, quantum fluctuations
suppress completely all magnetic orders, leading to a plaquette order phase
which breaks the lattice symmetry but preserves the spin SU(2) symmetry. On the
evidence of our numerical results, the quantum phase transition between the
antiferromagnetic phase and the plaquette phase is found to be either a direct
second order or a very weak first order transition.Comment: 6 pages, 9 figures, published versio
Soliton solutions of the improved quark mass density-dependent model at finite temperature
The improved quark mass density-dependent model (IQMDD) based on soliton bag
model is studied at finite temperature. Appling the finite temperature field
theory, the effective potential of the IQMDD model and the bag constant
have been calculated at different temperatures. It is shown that there is a
critical temperature . We also calculate the
soliton solutions of the IQMDD model at finite tmperature. It turns out that
when , there is a bag constant and the soliton solutions are
stable. However, when the bag constant and there is no
soliton solution, therefore, the confinement of quarks are removed quickly.Comment: 10 pages, 9 figures; Version to appear in Physical Review
Motion planning and control strategy of a cable-driven body weight support gait training robot
In this paper, a cable-driven body weight support gait training robot (C-BWSGTR) that provides patients with partial body weight support as well as a kind of stable gait training driving force was
designed; this device enabled those patients to walk again. Firstly, the overall
configuration of the C-BWSGTR was determined, and the structural
composition and working principle of the robot were established. Secondly, the
vector algebra method was applied to carry out the kinematic analysis and
establish the mathematical model of the C-BWSGTR. The displacement
of each cable during the patient gait training was also calculated. Thirdly, the
motion planning of the C-BWSGTR was carried out in stages, using the
time–phase distribution relationship based on an S-shaped speed curve.
Meanwhile, the displacement, speed, and acceleration of each
cable during the patient gait training were calculated and
corresponding change curves were generated. Finally, a position servo composite
control strategy for the C-BWSGTR was designed by analyzing the robot's
dynamic characteristics of the forward channel transfer function. The simulation
analysis and prototype experiment in this paper verified that the designed
composite position servo control strategy can meet the requirements of the
system with respect to stability and a fast response
of the system to the loading command.</p
Optical and transport properties in doped two-leg ladder antiferromagnet
Within the t-J model, the optical and transport properties of the doped
two-leg ladder antiferromagnet are studied based on the fermion-spin theory. It
is shown that the optical and transport properties of the doped two-leg ladder
antiferromagnet are mainly governed by the holon scattering. The low energy
peak in the optical conductivity is located at a finite energy, while the
resistivity exhibits a crossover from the high temperature metallic-like
behavior to the low temperature insulating-like behavior, which are consistent
with the experiments.Comment: 13 pages, 5 figures, accepted for publication in Phys. Rev. B65
(2002) (April 15 issue
Two Kinds of Iterative Solutions for Generalized Sombrero-shaped Potential in -dimensional Space
Based on two different iteration procedures the groundstate wave functions
and energies for N-dimensional generalized Sombrero-shaped potentials are
solved. Two kinds of trial functions for the iteration procedure are defined.
The iterative solutions are convergent nicely to consistent results for
different choices of iteration procedures and trial functions.Comment: 16 pages, 3 figure
A Stem Cell-Based Tool for Small Molecule Screening in Adipogenesis
Techniques for small molecule screening are widely used in biological mechanism study and drug discovery. Here, we reported a novel adipocyte differentiation assay for small molecule selection, based on human mesenchymal stem cells (hMSCs) transduced with fluorescence reporter gene driven by adipogenic specific promoter - adipocyte Protein 2 (aP2; also namely Fatty Acid Binding Protein 4, FABP4). During normal adipogenic induction as well as adipogenic inhibition by Ly294002, we confirmed that the intensity of green fluorescence protein corresponded well to the expression level of aP2 gene. Furthermore, this variation of green fluorescence protein intensity can be read simply through fluorescence spectrophotometer. By testing another two small molecules in adipogenesis –Troglitazone and CHIR99021, we proved that this is a simple and sensitive method, which could be applied in adipocyte biology, drug discovery and toxicological study in the future
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Review of distributed control and optimization in energy internet: From traditional methods to artificial intelligence-based methods
Abstract: Energy internet (EI) can alleviate the arduous challenges brought about by the energy crisis and global warming and has aroused the concern of many scholars. In the research of EI control systems, the access of distributed energy causes the power system to exhibit complex nonlinearity, high uncertainty and strong coupling. Traditional control and optimization methods often have limited effectiveness in solving these problems. With the widespread application of distributed control technology and the maturity of artificial intelligence (AI) technology, the combination of distributed control and AI has become an effective method to break through current research bottlenecks. This study reviews the research progress of EI distributed control technologies based on AI in recent years. It can be found that AI‐based distributed control methods have many advantages in maintaining EI stability and achieving optimal energy management. This combination of AI and distributed control makes EI control systems more intelligent, safe and efficient, which will be an important direction for future research. The purpose of this study is to provide a reference as well as useful research ideas for the study of EI control systems
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