一类非线性双曲型方程初边值问题解的爆破

该文给出一类非线性双曲型方程初边值问题解爆破的充分条件, 并证明问题局部解的存在性与唯一性     

Banach空间中脉冲积分-微分方程的迭代解

利用单调迭代技术,本文首先讨论了Banach空间一阶脉冲积分-微分方程初值问题最大解与最小解的存在性.在此基础上,讨论了右端项中带有一阶导数的二阶脉冲积分-微分方程初值问题最大解与最小解的存在性.最后的例子说明对导数的限制条件是可验证的.     

一类非线性高阶波动方程的初边值问题

该文研究一类非线性高阶波动方程u_tt－a_1^Uxx+a_₂u_x4+a₃u_x4_tt=φ(u_{x ⁾}x+f(u,u_x,u_xxu_xxx,u_x4)的初边值问题.证明整体古典解的存在唯一性并给出古典解爆破的充分条件.     

A new method of generating Ga slope in Cu(In,Ga)Se2 film by controlling Se content in a multi-stacked precursor

An appropriate Ga slope is required in Cu(In,Ga)Se₂ (CIGS) film to enhance the cell performance of CIGS thin-film solar cells. In the conventional three-stage-co-evaporation process, the Ga slope was obtained by controlling Ga/In flux during deposition process. However, in two-step process, where a precursor was deposited first and then annealed in a Se environment for mass production, the desirable Ga slope was not achievable with the Ga/In flux control. We observed that the Ga/(Ga + In) ratio was nearly flat in CIGS film for Se-rich precursor and the ratio was nearly zero at surface and very high on bottom side of CISG film for Se-deficient precursor. We were able to generate a CIGS film with a Ga non-zero Ga surface and desired slope in the bulk by devising a precursor with Se-rich layer on top and Se-deficient layer on bottom, resulting in the enhancement of Cell performance.     

Central Force Optimization with variable initial probes and adaptive decision space

An implementation of Central Force Optimization (CFO) utilizing variable initial probes and decision space adaptation is presented. The algorithm is tested against a suite of benchmark functions and CFO’s results compared to those of other algorithms. CFO performs well against the benchmarks, and also in scalability tests in 300-dimensions.     

Post-Newtonian Cosmology

Newtonian Cosmology is commonly used in astrophysical problems, because of its obvious simplicity when compared with general relativity. However it has inherent difficulties, the most obvious of which is the non-existence of a well-posed initial value problem. In this paper we investigate how far these problems are met by using the post-Newtonian approximation in cosmology.     

On convexity of solutions of ordinary differential equations

We prove a result on the convex dependence of solutions of ordinary differential equations on an ordered finite-dimensional real vector space with respect to the initial data.     

Mechanism of carbothermal reduction of iron, cobalt, nickel and copper oxides

A new scheme of thermal dissociation which is based on the dissociative evaporation of the reactant with simultaneous condensation of the low-volatile product has been invoked to interpret the kinetics of reduction of FeO, CoO, NiO and Cu₂O by carbon. A critical analysis of literature data and their comparison with theoretical calculations has shown that the main kinetic characteristics of carbothermal reduction, including the initial decomposition temperature and activation energy are in full agreement with the proposed mechanism of decomposition. Condensation of the low-volatile product (metal vapour) in the reaction zone and partial transport of condensation energy to the oxide account for the features which are typical of solid state reactions and manifest themselves in the appearance of periods of induction and acceleration in the course of the process. Carbon fulfils the role of buffer in this process. This is supported by an appearance of metals in the condensed phase and a higher than equilibrium partial pressure of oxygen in high-vacuum experiments with Knudsen cells.     

High-performance optical modulators bias control system without dither

A software-based bias control system of push–pull Mach–Zehnder modulators (MZMs) without dither tone is described in this paper. The slope of the average optical output power respect to the bias voltage is used to control the operating bias points in the automatic control system. The paper analyses the theory of automatic bias control intensively and verifies the effectiveness of the proposed technique which is a modulation-format-free method under the RF signal through testing and contrasting the BER (bit error rate) between the new technique and manual measure on the experimental platform. Based on this, an automatic bias control system set up by an optical QPSK composed by double MZMS on the LabVIEW platform is described.     

Strength softening models of soil and its application in rainfall-induced landslidesimulation

In this study, strength softening models are developed for exploring rainfall-induced landslide mechanism based on Mohr-Coulombstrength theory with both saturation degree and temporal evolution into consideration. According tothe ratio of two time scales available, the model can be classified into three categories, i.e., instant softeningmodel, delay softeningmodel, and couplingsoftening model.Corresponding evolution functions are specified to represent these kinds of softening processes andthen applied to simulate landslide of homogeneous slopes triggered by rainfall, therefrom, usefulconclusions can be drawn in the end.