With powerful nonlinear mapping and fitting ability of neural network, a production predicting neural network model is constructed. In view of high error, easy to default and other characteristics of oil field production data or data fitting and prediction is not easy to converge, a method of extended training data set and improved mean square error loss function are presented to get remarkable results in oil production fitting.

Controlling Hopf bifurcation in a fluid-flow model for congestion control in wireless networks, we propose a state feedback controller. Choosing communication delay as a bifurcation parameter, we proved that with the controller, one can change critical value of bifurcation and enlarge stable region. Hopf bifurcation of the system is delayed. Moreover, by choosing appropriate parameters, we change easily stability and direction of bifurcating periodic solutions. Theoretical analysis and numerical results verifies that the method controls Hopf bifurcation effectively.

Conjugate gradient method (CGM) is developed for the estimation of surface heat flux in two-dimensional variable geometry heat conduction problem from temperature measurements.In typical exemplified case,it is shown that CGM is feasible and robust.Further studies reveal that estimated results are influenced by number of measurement points and initial estimation.The number of measurement points are related to intensity of heat flux spatial variation.And the final heat flux should be chosen as the initial estimation.

Temperature-dependent thermal conductivity k(T)and specific heat C(T)are estimated simultaneously.At first,k(T) and C(T)are rewritten as functions of position and time,k(x,t)and C(x,t),and the gradient of cost function is deduced with adjoint equation method(AEM).Temperature is divided into segments and thermal conductivity and specific heat are expressed as constant in each segment.Gradients of cost function with respect to k(T)and C(<T)are further deduced from gradients of cost function with respect to k(x,t)and C(x,t).With a typical inversion problem,it is shown that the inversion method is feasible,effective and not too sensitive to measurement noise.

A two-dimensional Gross-Pitaevskii equation describing Bose-Einstein condensation in an axial symmetry nonharmonic trap is solved.Converged wave functions,chemical potentials,and internal energies in Bose-Einstein condensation are obtained.Ground-state of Bese-Einstein condensation with atomic interaction is investigated.A comparison between harmonic and non-harmonic traps is reported.

A method called Rayleigh integral linear superposition algorithm is introduced, in which nonlinear propagation and high order harmonic attenuation are considered. Principle of the method is analyzed. For a concave spherical transducer, medium attenuation and nonlinear propagation in sound focused region are studied. The method is compared with Khokhov-Zabolotskaya-Kuznesov (KZK) method. It is shown that the method is effective in calculating high-intensity focused ultrasound(HIFU) sound fields.

The mean short path of network is discussed. The mean short path of the network product is equal to the sum of the mean short path of the networks. Based on this we calculate the mean short path of several constructed networks.

The total energy and cohesive energy of typical binary compounds, namely, NiAl, SiC, GaAs, MgS and NaCl, are studied by using he linearized augmented plane-wave method. Special emphasis is put on the effects of the choice of muffin-tin radii of the two elements. Results show that, for closely packed alloy NiAl, the variation of MT radius yields little change to the total energy; and the atomic covalent radii could be used in setting the MT radii for covalent crystals such as SiC and GaAs; but the ionic radii are not appropriate for crystals with strong ionic bonds such as MgS and NaCl due to a large number of core electrons lost out of the mufin-tin spheres of cations. The calculated cohesive energies with proper choice of muffin-tin radii are in good agreement with experimental results.

All-electron self-consistent linearized augmented planewave band method in the local spin density functional and warped muffin tin approximation is used to calculate the cohesive energy of as many as 58 elemental crystals including not only simple, noble and transition metals, but also the covalent and inert gas so lids. Calculation scheme for achieving good results for this wide range of cryst a ls is thoroughly discussed. The numerical results are in general agreement with those of other band-structure methods and the experimental data.

It describes an improved numerical model and calculation method for stability simulation of a pulse tube refrigerator.A set of differential equations based on the conservation of mass,energy and momentum for oscillating fluid flow is solved by numerical method.A variety of physical factors,such as actual gas,gas flow friction,heat transfer in the heat exchanger and regenerator,ect.are included to improve the accuracy of the model.The results show the changes of mass flow,pressure,temperature,enthalpy flow and so on in each cell with time.The computer predicted performance is compared with the experimental data.Good agreement has been found between the two.