Control of GaN inverted pyramids growth on c-plane patterned sapphire substrates

Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar facets.In this work,GaN inverted pyramids are directly grown on c-plane patterned sapphire substrates(PSS)by metal organic vapor phase epitaxy(MOVPE).The influences of growth conditions on the surface morphol-ogy are experimentally studied and explained by Wulff constructions.The competition of growth rate among{0001},{1011},and{1122}facets results in the various surface morphologies of GaN.A higher growth temperature of 985°C and a lowerⅤ/Ⅲratio of 25 can expand the area of{}facets in GaN inverted pyramids.On the other hand,GaN inverted pyramids with almost pure{}facets are obtained by using a lower growth temperature of 930℃,a higherⅤ/Ⅲratio of 100,and PSS with pattern arrangement perpendicular to the substrate primary flat.

Storage reliability assessment model based on competition failure of multi-components in missile

The degradation data of multi-components in missile is derived by periodical testing. How to use these data to assess the storage reliability (SR) of the whole missile is a difficult problem in current research. An SR assessment model based on competition failure of multi-components in missile is proposed. By analyzing the missile life profile and its storage failure feature, the key components in missile are obtained and the characteristics voltage is assumed to be its key performance parameter. When the voltage testing data of key components in missile are available, a state space model (SSM) is applied to obtain the whole missile degradation state, which is defined as the missile degradation degree (DD). A Wiener process with the time-scale model (TSM) is applied to build the degradation failure model with individual variability and nonlinearity. The Weibull distribution and proportional risk model are applied to build an outburst failure model with performance degradation effect. Furthermore, a competition failure model with the correlation between degradation failure and outburst failure is proposed. A numerical example with a set of missiles in storage is analyzed to demonstrate the accuracy and superiority of the proposed model.

The entanglement between two isolated atoms in the double mode mode competition model

Extending the double Jaynes Cummings model to a more complicated case where the mode-mode competition is considered, we investigate the entanglement character of two isolated atoms by means of concurrence, and discuss the dependence of atom atom entanglement on the different initial state and the relative coupling strength between the atom and the corresponding cavity field. The results show that the amplitude and the period of the atom atom entanglement evolution can be controlled by the choice of initial state and relative coupling strength, respectively. We find that the phenomenon of entanglement sudden death （ESD） is sensitive to the initial conditions. The length of the time interval for zero entanglement depends not only on the initial degree of entanglement between two atoms but also on the relative coupling strength of atom field interaction. The ESD effect can be weakened by enhancing the mode-mode competition between the three- and single-photon processes.

What Competition Model for Economic Development Should China Adopt at the Present Stage?

As a major developing country,China has attracted significant attention as to whichpathitshouldfol owfortechnologicalprogress.Accordingtotheauthorofthispaper,Chinashouldcontinueto pursue the international division of labor and competition strategy based on comparative advantages.Meanwhile,China should,through reform and adjustment,build a national innovation system capable ofplaying an e ective role in the future.However,laying too much emphasis on proprietary innovation atthe present stage wil bring about undesirable consequences.The timing for China to embark on a path oftechnologicaldevelopmentthroughproprietaryinnovationissubjecttothechangesbothintradeconditionsandin income distribution e ects arising from proprietary innovation.

THE DISCRETE DYNAMICS FOR COMPETITIVE POPULATIONS OF LOTKA-VOLTERRA TYPE

The discrete dynamics for competition populations of Lotka-Volterra type modeled as N1(t+1)=N1(t) exp[r1(1-N1-b12N2)], N2(t+1)=N2(t) exp[r2(1-N2-b21N1)] is considered in the paper. In the case of non-persistence the attractive behavior of model has been discussed. Especially, there are two attractive sets when h_(ij)>1, and the attractive behaviors are more complicated than that of the corresponding cofitinuous model. The attracted regions are given. We prove that the model is also persistent in the degenerate case of b_(ij)=1. In the persistence case of b_(ij)<1, the existence and uniqueness for two-period points of the model are studied at r1=r2. The condition for the multi-pair of two-period points is indicated and their influences on population dynamical behaviors are shown.

Road Resources Distribution and Evolution Analysis Using a Species Competition Model for Improving Road Equity

The paper analyzes the equity of road resources distribution in urban areas by modeling the competitive relationship among different road users. A logistic model is used to describe the development of different traffic modes in the transportation network. The system is similar to the species competition model, so a two-species model is used to analyze the relationship between users based on the stability of the equilibrium points. The Lotka-Volterra model is then used to describe the multi-species cases with numerical examples, showing that this model can describe the effects of the road space distribution on the competitive user relationships. Policy makers must ensure the equity of road resources distribution so that each urban transportation mode is properly developed for sustainable social development.

Bifurcation control of a fractional-order delayed competition and cooperation model of two enterprises

The competition and cooperation among enterprises has become a hot topic and focus issue in today’s world. How to manage the enterprise well so as to achieve the maximum output is an important problem for enterprise managers. Optimizing output of two enterprises plays a key role in operating enterprises. Many scholars pay much attention to this aspect. However, the reports on the stability and Hopf bifurcation for fractional-order delayed competition and cooperation model of two enterprises are very few. This paper is concerned with the stability, the existence of Hopf bifurcation and the bifurcation control issue of fractionalorder delayed competition and cooperation model of two enterprises. Firstly, some new sufficient conditions that guarantee the stability and the existence of Hopf bifurcation for fractional-order delayed competition and cooperation model of two enterprises are obtained by regarding the delay as bifurcation parameter. Then a suitable time delayed feedback controller is designed to control the Hopf bifurcation for involved model. The study shows that the delay and the fractional order have an important effect on the stability and Hopf bifurcation of involved model. Some simulations justifying the validity of the derived analytical results are given. At last, we end this paper with a concise conclusion. The obtained results of this article are innovative and are of great significance in handling the competition and cooperation among enterprises.

Strategic Bidding in Distribution Network Electricity Market Focusing on Competition Modeling and Uncertainties

Developing the electricity market at the distribution level can facilitate the energy transactions in distribution networks with a high penetration level of distributed energy resources(DERs)and microgrids(MGs).However,the lack of comprehensive information about the marginal production cost of competitors leads to uncertainties in the optimal bidding strategy of participants.The electricity demand within the network and the price in the wholesale electricity market are two other sources of the uncertainties.In this paper,a day-ahead-market-based framework for managing the energy transactions among MGs and other participants in distribution networks is introduced.A game-theory-based method is presented to model the competition and determine the optimal bidding strategy of participants in the market.Robust optimization technique is employed to capture the uncertainties in the marginal cost of competitors.Additionally,the uncertainties in demand are modeled using a scenario-based stochastic approach.The results ob-tained from case studies reveal the merit of considering competition modeling and uncertainties.

EXISTENCE OF POSITIVE PERIODIC SOLUTION TO A CLASS OF NEUTRAL DELAY COMPETITION MODEL

By means of the theory of coincidence degree, sufficient condition for the existence of positive periodic solution to certain neutral delay competition model is obtained.

GLOBAL ANALYSIS TO A KIND OF COMPETITION MODEL OF E-COMMERCE SITES

In this paper, we present a competition modei of e-commerce sites with the property of 'better for better'. Then we qualitatively analyze the special case of two dimensions. So we prove that there does not exist limit cycle, in the first quadrant of the phase plane and all trajectories tend to some singular points.

Positive Solutions for a Competition Model with an Inhibitor Involved

In the paper, we study the positive solutions of a diffusive competition model with an inhibitor involved subject to the homogeneous Dirichlet boundary condition. The existence, uniqueness, stability and multiplicity of positive solutions are discussed. This is mainly done by using the local and global bifurcation theory.

GLOBAL ANALYSIS OF AN EBENMAN＇S MODEL OF POPULATION WITH TWO COMPETING AGE CLASSES

Several global conclusions about an Ebenman's model of a population with competing juveniles and adults are derived in this paper. The problems about the number of non-trivial fixed points, the number of synchronous 2-cycles, and the number of attracting synchronous cycles are resolved. In a special case, the twice iteration of the 2-dimensional map can be reduced to a 1-dimensional map, and the existence of one or more continua of non-synchronous 2-cycles is pointed out. Numerical calculations are used to draw orbit diagrams which show complicated dynamics of this non-invertible 2-dimensional map. Experimental and field observational evidence is also discussed.

Scaling relation of domain competition on(2+1)-dimensional ballistic deposition model with surface diffusion

During heteroepitaxial overlayer growth multiple crystal domains nucleated on a substrate surface compete with each other in such a manner that a domain covered by neighboring ones stops growing.The number density of active domains ρ decreases as the height h increases.A simple scaling argument leads to a scaling law of ρ~ h^（-γ） with a coarsening exponent γ=d/z,where d is the dimension of the substrate surface and z the dynamic exponent of a growth front.This scaling relation is confirmed by performing kinetic Monte Carlo simulations of the ballistic deposition model on a two-dimensional（d=2） surface,even when an isolated deposited particle diffuses on a crystal surface.

PERIODIC SOLUTION OF A NEUTRALDELAY COMPETITION MODEL

In this paper, we use topological degree method to obtain the existence of a positive periodicsolution of the neutral delay competition modelwhere α,β,ri,ki,ci (i=1,2) are positive continuous ω-periodic functions and rj (j=0,1,…,4) arenonnegative constants.

Incorporating two coupling noises into a nonlinear competitive system with saturation effect

In this paper,a novel stochastic two-species competitive system with saturation effect is formulated,in which there exist two noise resources and their coupling mode is relatively complex and every noise source has elfect on the intrinsic growth rates of both species.With the help of some suitable Lyapunov functions,sufficient conditions for stochastic permanence are established as exponential extinction,extinction,permanence in time average and asymptotic pathwise estimation of system.The effect of coupling noise on the asymptotic behaviors of the populations is shown.

Nodal, zonal, or uniform electricity pricing： how to deal withnetwork congestion

In this paper, the main contributions to congestion management and electricity pricing, i.e., nodal, zonal, and uniform electricity pricing, are surveyed. The key electricity market concepts are structured and a formal model framework is proposed for electricity transportation, production, and consumption in the context of limited transmission networks and competitive, welfare maximizing electricity markets. In addition, the main results of existing short-run and long-run congestion management studies are explicitly summarized. In particular, the important interconnection between short-run network management approaches and optimal long-run investments in both generation facilities and network lines are highlighted.