珠心算排积法论

负加10差值法也适用于正加10差值法。它的方式是后减前。

Clarkson-Kruskal Direct Similarity Approach for Differential-Difference Equations

In this letter, the Clarkson-Kruskal direct method is extended to similarity reduce some differentialdifference equations. As examples, the differential-difference KZ equation and KP equation are considered.

Non-isothermal crystallization kinetics of Nylon 10T and Nylon 10T/1010 copolymers:Effect of sebacic acid as a third comonomer

Nylon 10 T and Nylon 10T/1010 samples were synthesized by direct melt polymerization. The non-isothermal crystallization kinetics of Nylon 10 T and Nylon 10T/1010 was investigated by means of differential scanning calorimetry(DSC). Jeziorny equation and Mo equation were applied to describe the non-isothermal crystallization kinetics of the Nylon 10 T and the Nylon 10T/1010. The activation energies for non-isothermal crystallization were obtained by Vyazovkin's method and Friedman's method, respectively. These results showed that Jeziorny equation and Mo equation well described the non-isothermal crystallization kinetics of the Nylon 10 T and the Nylon 10T/1010. It was found that the values of the activation energy for non-isothermal crystallization of the Nylon 10T/1010 were lower than those of the Nylon 10 T at a given temperature or relative crystallinity degree,which revealed that crystallization ability of the Nylon 10T/1010 was higher. The crystal morphology was observed by means of a polarized optical microscope(POM) and X-ray diffraction(XRD). It was found that the addition of sebacic acid comonomer not only did not change the crystal form of the Nylon 10 T, but also significantly increased the number and decreased the size of spherulites. Comparing with the Nylon 10 T, the crystallization rate was increased with the addition of the sebacic acid comonomer.

Transient analysis of Casson fluid thermo-convection from a vertical cylinder embedded in a porous medium: Entropy generation and thermal energy transfer visualization

Thermal transport in porous media has stimulated substantial interest in engineering sciences due to increasing applications in filtration systems,porous bearings,porous layer insulation,biomechanics,geomechanics etc.Motivated by such applications,in this article,a numerical study of entropy generation impacts on the heat and momentum transfer in time-dependent laminar incompressible boundary layer flow of a Casson viscoplastic fluid over a uniformly heated vertical cylinder embedded in a porous medium is presented.Darcy’s law is used to simulate bulk drag effects at low Reynolds number for an isotropic,homogenous porous medium.Heat line visualization is also included.The mathematical model is derived and normalized using appropriate transformation variables.The resulting non-linear time-dependent coupled governing equations with associated boundary conditions are solved via an implicit finite difference method which is efficient and unconditionally stable.The outcomes show that entropy generation and Bejan number are both elevated with increasing values of Darcy number,Casson fluid parameter,group parameter and Grashof number.To analyze the heat transfer process in a two-dimensional domain,plotting heat lines provides an excellent approach in addition to streamlines and isotherms.It is remarked that as the Darcy number increases,the deviations of heat lines from the hot wall are reduced.

Improved modal truncation error in the directly analytical method for damage identification of frame structures

The damage identification is made by the numerical simulation analysis of a five-storey-and-two-span RC frame structure, using improved and unimproved direct analytical method respectively; and the fundamental equations were solved by the minimal least square method （viz. general inverse method）. It demonstrates that the feasibility and the accuracy of the present approach were impoved significantly, compared with the result of unimproved damage identification.

Path-tracking Control of Underactuated Ships Under Tracking Error Constraints

This paper presents a constructive design of new controllers that force underactuated ships under constant or slow time-varying sea loads to asymptotically track a parameterized reference path, that guarantees the distance from the ship to the reference path always be within a specified value. The control design is based on a global exponential disturbance observer, a transformation of the ship dynamics to an almost spherical form, an interpretation of the tracking errors in an earth-fixed frame, an introduction of dynamic variables to compensate for relaxation of the reference path generation, p-times differentiable step functions, and backstepping and Lyapunov＇s direct methods. The effectiveness of the proposed results is illustrated through simulations.

Large electrocaloric effect in BaTiO_3 based multilayer ceramic capacitors

The electrocaloric effect(ECE) of multilayer ceramic capacitor(MLCC) of Y5 V type was directly measured via a differential scanning calorimetry(DSC) method and a reference resistor was used to calibrate the heat flow due to the heat dissipation. The results are compared with those calculated from Maxwell relations by using the polarization data obtained from the polarization–electric field hysteresis loops. The direct method shows a larger ECE temperature change, which is accounted for the situation approaches an ideal condition. For the indirect method using Maxwell relations, only the polarization projection along the electric field was taken into account, which will be less than the randomly distributed real polarizations that contribute to the ECE. The MLCCs exhibit a broad peak of ECE around 80 C, which will be favorite for the practical ECE cooling devices.

FDTD analysis of the optical properties of vertical ZnO nanorod array

Based on the structure and dimensions of a vertical ZnO nanorod array(V-ZNA)sample,an ideal 2-D photonic crystal model was established.The optical properties of the V-ZNAs were analyzed with finite-difference time-domain(FDTD)method,and the influences of the geometry parameters,including the circumcircle diameters of the top and bottom surfaces(Dt and Db)and the height(H)of the nanorods,and the pitch between each column(L),were discussed.High transmittance and low reflectance in the waveband of 400–800 nm were proved,and the highest transmittance can be obtained with Dt<50 nm,H=200 nm,and Db/L=0.85,which was verified by Effective Index Method(EIM).The result indicates that V-ZNAs can be used as excellent light coupling element and antireflection material for solar energy applications.