Simulation on Residual Stress of Shot Peening Based on a Symmetrical Cell Model

The symmetrical cell model is widely used to study the residual stress induced by shot peening. However, the correlation between the predicted residual stresses and the shot peening coverage, which is a big challenge for the researchers of the symmetrical cell model, is still not established. Based on the dynamic stresses and the residual stresses outputted from the symmetrical cell model, the residual stresses corresponding to full coverage are evalu- ated by normal distribution analysis. The predicted nodal dynamic stresses with respect to four corner points indicate that the equi-biaxial stress state exists only for the first shot impact. Along with the increase of shot number, the interactions of multiple shot impacts make the fluctuation of the nodal dynamic stresses about an almost identical value more and more obvious. The mean values and standard deviations of the residual stresses gradually tend to be stable with the increase of the number of shot peening series. The mean values at each corner point are almost the same after the third peening series, which means that an equi-biaxial stress state corresponding to the full coverage of shot peening is achieved. Therefore, the mean values of the nodal residual stresses with respect to a specific transverse cross-section below the peened surface can be used to correlate the measured data by X-ray. The predicted residual stress profile agrees with the experimental results very well under 200% peening coverage. An effective correlation method is proposed for the nodal residual stresses predicted by the symmetrical cell model and the shot peening coverage.

Evaluation of the Witten Index in 1+1 Dimensional Supersymmetric Models with O(N) Symmetry

We present a way to calculate the Witten indexΔfor a class of l+l dimensional supersymmetric(SUSY)models with O(N)symmetry.SinceΔis invariant under an adiabatic change of parameters,an O(N)non-invariant but SUSY term 2hФN is added to the Lagrangian,therefore the degeneracy of zero-energy states due to O(N)symmetry is removed.It is shown that SUSY breaking can occur for the SUSY O(N)Wess-Zumino model.

Compliance Modeling of a Compliant Stage with Symmetric Configuration

This paper presents the compliance modeling of a compliant stage with symmetric configuration. Empirical compliance equations for the circular flexure hinge are first introduced. Using the matrix method, the output compliance of a compliant stage with symmetric configuration is then obtained. Finally, the compliances derived from the proposed theoretical model and finite element analysis (FEA) are compared. It indicates that the results calculated by the theoretical model are in good agreement with those derived from FEA, which demonstrates the accuracy of the theoretical model.

Anisotropic Plane Symmetric Two-Fluid Cosmological Model with Time-Varying G and A

We investigate a two-fluid anisotropic plane symmetric cosmological model with variable gravitational constant G（t） and cosmological term A（t）. In the two-fluid model, one fluid is chosen to be that of the radiation field modeling the cosmic microwave background and the other one a perfect fluid modeling the material content of the universe. Exact solutions of the field equations are obtained by using a special form for the average scale factor which corresponds to a specific time-varying deceleration parameter. The model obtained presents a cosmological scenario which describes an early acceleration and late-time deceleration. The gravitation constant increases with the cosmic time whereas the cosmological term decreases and asymptotically tends to zero. The physical and kinematical behaviors of the associated fluid parameters are discussed.

Robust Stability of Nonlinear Plants with a Non-symmetric Prandtl-Ishlinskii Hysteresis Model

In this paper, robust stability of nonlinear plants represented by non-symmetric Prandtl-Ishlinskii （PI） hysteresis model is studied. In general, PI hysteresis model is the weighted superposition of play or stop hysteresis operators, and the slopes of the operators are considered to be the same. In order to make a hysteresis model, a modified form of non-symmetric play hysteresis operator with unknown slopes is given. The hysteresis model is described by a generalized Lipschitz operator term and a bounded parasitic term. Since the generalized Lipschitz operator is unknown, a new condition using robust right coprime factorization is proposed to guarantee robust stability of the controlled plant with the hysteresis nonlinearity. As a result, based on the proposed robust condition, a stabilized plant is obtained. A numerical example is presented to validate the effectiveness of the proposed method.

Itinerant Topological Magnons in SU (2) Symmetric Topological Hubbard Models with Nearly Flat Electronic Bands

We show that a suitable combination of flat-band ferromagnetism,geometry and nontrivial electronic band topology can give rise to itinerant topological magnons.An SU(2) symmetric topological Hubbard model with nearly flat electronic bands,on a Kagome lattice,is considered as the prototype.This model exhibits ferromagnetic order when the lowest electronic band is half-filled.Using the numerical exact diagonalization method with a projection onto this nearly flat band,we can obtain the magnonic spectra.In the flat-band limit,the spectra exhibit distinct dispersions with Dirac points,similar to those of free electrons with isotropic hoppings,or a local spin magnet with pure ferromagnetic Heisenberg exchanges on the same geometry.Significantly,the non-flatness of the electronic band may induce a topological gap at the Dirac points,leading to a magnonic band with a nonzero Chern number.More intriguingly,this magnonic Chern number changes its sign when the topological index of the electronic band is reversed,suggesting that the nontrivial topology of the magnonic band is related to its underlying electronic band.Our work suggests interesting directions for the further exploration of,and searches for,itinerant topological magnons.

Modeling and Simulations in Symmetrical Supercapacitors Using Time Domain Mathematical Expressions

This study presents the deduction of time domain mathematical equations to simulate the curve of the charging process of a symmetrical electrochemical supercapacitor with activated carbon electrodes fed by a source of constant electric potential in time ε and the curve of the discharge process through two fixed resistors. The first resistor RCo is a control that aims to prevent sudden variations in the intensity of the electric current i1(t) present at the terminals of the electrochemical supercapacitor at the beginning of the charging process. The second resistor is the internal resistance RA of the ammeter used in the calculation of the intensity of the electric current i1(t) over time in the charging and discharging processes. The mathematical equations generated were based on a 2R(C + kUC(t)) electrical circuit model and allowed to simulate the effects of the potential-dependent capacitance (kUC(t)) on the charge and discharge curves and hence on the calculated values of the fixed capacitance C, the equivalent series resistance (ESR), the equivalent parallel resistance (EPR) and the electrical potential dependent capacitance index k.

A New Symmetric Model for Predicting Ternary Thermodynamic Properties from its Three Binary Systems

A new symmetric model for predicting ternary thermodynamic properties from its three binary systems has been presented. The application of this new model to the prediction of the ternary mixing enthalpy of Ga-Bi-Sn system and the ternary excess Gibbs energy of AgCl-LiCl-KCl system shows that the calculated results are close to the experimental data.

基于ICE的SIP穿越Symmetric NAT技术的改进

针对SIP(会话发起协议)穿越NAT设备的问题,提出ICE(交互式连通建立方式)协助SIP穿越Symmetric NAT的优化方案。设计端口分配服务器,实现针对SIP和ICE特性的改进端口预测模型,智能化ICE检测列表和改进连通检测过程,使SIP能够采用UDP直连方式高效穿越绝大部分Symmetric NAT。大量实验结果表明,改进方案保持了传统ICE方法不改动NAT设备的优点,有效提高了针对Symmetric NAT的穿越效率,缩短了ICE连通性检测过程的时间,满足更多企业使用Symmetric NAT提高信息安全性的需求。

Multinucleon transfer dynamics in nearly symmetric nuclear reactions

Within the framework of the dinuclear system model,the multinucleon transfer dynamics for nearly symmetric nuclear collisions has been investigated.The reaction mechanism in the systems of 198Pt+198Pt and 204Hg+198Pt was investigated at beam energies around the Coulomb barrier.It was found that the isotopic yields are enhanced with increased incident energy in the domain of proton-rich nuclides.However,the production on the neutron-rich side weakly depends on the energy.The angular distribution with the beam energy was also analyzed in the multinucleon transfer reactions.Projectile-like fragments were produced toward the forward emission with increasing incident energy.The target-like fragments manifested the opposite trend in the transfer reactions.

ADAPTIVE CONTROLLER AND ITS APPLICATION IN FORCE SYSTEM OF ASYMMETRIC CYLINDER CONTROLLED BY SYMMETRIC VALVE

Partial pressure, system vibration and asymmetric system dynamic performance exit in asymmetric cylinder controller by symmetric valve hydraulic system. To solve this problem in the force control system, model reference adaptive controller is designed using equilibrium point stability theory and output error equation polynomial. The reference model is selected in such a way that it meets the system dynamic performance. Hardware configuration of asymmetric cylinder controlled by asymmetric valve hydraulic system is replaced by intelligent control algorithm, thus the cost is lowered and easy to application. Simulation results demonstrate that the proposed adaptive control sheme has good adaptive ability and well solves asymmetric dynamic performance problem. The designed adaptive controller is fairly robust to load disturbance and system parameter variation.

Research on the Control for the Planar Motor by Non-symmetric and Unilateral Driven

与由四组线圈单元驱动方式相比，三组线圈单元驱动的平面电机属于单边非质心驱动模型。为提高平面电机系统的伺服性能，需要准确的力解耦模型以及有效的控制算法。由于实际中存在建模误差，如永磁体线圈加工误差引起的推力误差、气隙厚度不均匀、外部不确定扰动等，使得基于名义模型的系统无法有效解耦。同时建模误差的存在使得闭环系统误差方程的等号右侧不为0，无法确保跟踪误差的收敛。因此，必须利用控制器对建模误差进行补偿。以三组线圈单元且x方向为单边非质心驱动的平面电机作为研究对象。为提高其轨迹跟踪与定位能力，提出一种非线性控制算法。在逆动力学控制算法的基础上增加鲁棒项，对建模误差进行有效补偿。采用李雅普诺夫（Lyapunov）理论证明了该算法的稳定性。实验结果表明，轨迹跟踪误差小于1．5μm，可见通过对建模误差的补偿，减小了多自由度间耦合作用对运动精度的影响，提高了平面电机伺服性能。

Radiation energy flux of Dirac field of static spherically symmetric black holes

By the statistical entropy of the Dirac field of the static spherically symmetric black hole, the result is obtained that the radiation energy flux of the black hole is proportional to the quartic of the temperature of its event horizon. That is, the thermal radiation of the black hole always satisfies the generalised Stenfan-Boltzmann law. The derived generalised Stenfan-Boltzmann coefficient is no longer a constant. When the cut-off distance and the thin film thickness are both fixed, it is a proportional coefficient related to the space-time metric near the event horizon and the average radial effusion velocity of the radiation particles from the thin film. Finally, the radiation energy fluxes and the radiation powers of the Schwarzschild black hole and the Reissner-NordstrSm black hole are derived, separately.

Multiobjective Nonlinear Symmetric Duality Involving Generalized Pseudoconvexity

The purpose of this paper is to introduce second order (K, F)-pseudoconvex and second order strongly (K, F)- pseudoconvex functions which are a generalization of cone-pseudoconvex and strongly cone-pseudoconvex functions. A pair of second order symmetric dual multiobjective nonlinear programs is formulated by using the considered functions. Furthermore, the weak, strong and converse duality theorems for this pair are established. Finally, a self duality theorem is given.

Single Production of Top Quark via e^-γ Collision in Left-Right Twin Higgs Model

In the context of the left-right twin Higgs （LRTH） model, we fist study single production of the standard model （SM） top quark via e-γ collisions. We find that the corrections of the LRTH model to the cross section of the process e-γ→vebt might be observed only for f ≤750 GeV and the heavy top quark mass scale M ≥500 GeV in future high energy linear e^＋e^- collider （LC） experiment with the center-of-mass （CM） energy √s = 500 GeV and a yearly integrated luminosity of ￡ = 100 fb^-1. We also consider single production of the heavy top quark T via e-γ collisions. Our numerical results show that the possible signals of the heavy top quark T might be observed via the decay channel T →Ф^＋b→tbb in future LC experiment with √s = 3 TeV and ￡ = 500 fb^-1.

Production of Charged Higgs Bosons from Left-Right Twin Higgs Model at TeV Energy e^-γ Colliders

The left-right twin Higgs （LRTH） model predicts the existence of three additional Higgs bosons： one neutral Higgs φo and a pair of charged Higgs bosons φ±. In this paper, we study two pair production processes of these new particles at the next generation eγ colliders, i.e., e-γ → e-φ＋φ- , and e-γ→vRφ-φ0. We find that the production cross section of the process e-γ → e-φ＋φ- are at the level of several tens fb, the production cross section of the process e-γ→vRφ-φ0 can reach 0.35 fb with the reasonable parameter values. As long as the charged Higgs bosons are not too heavy, we conclude that these processes might be used to test for the left-right twin Higgs model in future high-energy linear collider experiments.

Associated ZH and WH Production in Left-Right Twin Higgs Model at LHC

At the CERN large hadron collider （LHC）, production of the Higgs boson in association with Z or W bosons provides a dramatic experimental signal for detecting the standard model （SM） Higgs boson. In this paper, we consider the contributions of the left-right twin Higgs （LRTH） model to the processes qq＇ --~ Z（W）H. Our numerical results show that, in the favorable parameter spaces, the cross sections deviate distinctly from the predictions of the SM. The possible signals of the LRTH model can be detected via these processes at the LHC experiments.

Single Production of Charged Gauge Boson W_H^-from Left-Right Twin Higgs Model in Association with Top Quark at LHC

The twin Higgs mechanism has recently been proposed to solve the little hierarchy problem. In the context of the left-right twin Higgs （LRTH） model, we discuss single production of the new charged gauge boson WH^- , which is predicted by the left-right twin Higgs model, in association with top quark at the CERN Large Hadron Collider （LHC）. It is found that, for a typical nonzero value of mass mixing parameter M = 150 GeV in the LRTH model, the production cross section is in the range of 3 ×10^-2 - 6.07×10^3 fb at the LHC. As long as the WH^- is not too heavy, the possible signatures of the heavy charged gauge boson might be detected at the LHC experiments.

Utilization of Logistical Regression to the Modified Sine-Gordon Model in the MST Experiment

In this paper, a logistical regression statistical analysis (LR) is presented for a set of variables used in experimental measurements in reversed field pinch (RFP) machines, commonly known as “slinky mode” (SM), observed to travel around the torus in Madison Symmetric Torus (MST). The LR analysis is used to utilize the modified Sine-Gordon dynamic equation model to predict with high confidence whether the slinky mode will lock or not lock when compared to the experimentally measured motion of the slinky mode. It is observed that under certain conditions, the slinky mode “locks” at or near the intersection of poloidal and/or toroidal gaps in MST. However, locked mode cease to travel around the torus;while unlocked mode keeps traveling without a change in the energy, making it hard to determine an exact set of conditions to predict locking/unlocking behaviour. The significant key model parameters determined by LR analysis are shown to improve the Sine-Gordon model’s ability to determine the locking/unlocking of magnetohydrodyamic (MHD) modes. The LR analysis of measured variables provides high confidence in anticipating locking versus unlocking of slinky mode proven by relational comparisons between simulations and the experimentally measured motion of the slinky mode in MST.

Nonlinear Mathematical Modeling and Sensitivity Analysis of Hydraulic Drive Unit

The previous sensitivity analysis researches are not accurate enough and also have the limited reference value, because those mathematical models are relatively simple and the change of the load and the initial displacement changes of the piston are ignored, even experiment verification is not conducted. Therefore, in view of deficiencies above, a nonlinear mathematical model is established in this paper, including dynamic characteristics of servo valve, nonlinear characteristics of pressure-flow, initial displacement of servo cylinder piston and friction nonlinearity. The transfer function block diagram is built for the hydraulic drive unit closed loop position control, as well as the state equations. Through deriving the time-varying coefficient items matrix and time-varying free items matrix of sensitivity equations respectively, the expression of sensitivity equations based on the nonlinear mathematical model are obtained. According to structure parameters of hydraulic drive unit, working parameters, fluid transmission characteristics and measured friction-velocity curves, the simulation analysis of hydraulic drive unit is completed on the MATLAB/Simulink simulation platform with the displacement step 2 mm, 5 mm and 10 mm, respectively. The simulation results indicate that the developed nonlinear mathematical model is sufficient by comparing the characteristic curves of experimental step response and simulation step response under different constant load. Then, the sensitivity function time-history curves of seventeen parameters are obtained, basing on each state vector time-history curve of step response characteristic. The maximum value of displacement variation percentage and the sum of displacement variation absolute values in the sampling time are both taken as sensitivity indexes. The sensitivity indexes values above are calculated and shown visually in histograms under different working conditions, and change rules are analyzed. Then the sensitivity indexes values of four measurable parameters, such as supply pressure, proportional gain, initial position of servo cylinder piston and load force, are verified experimentally on test platform of hydraulic drive unit, and the experimental research shows that the sensitivity analysis results obtained through simulation are approximate to the test results. This research indicates each parameter sensitivity characteristics of hydraulic drive unit, the performance-affected main parameters and secondary parameters are got under different working conditions, which will provide the theoretical foundation for the control compensation and structure optimization of hydraulic drive unit.