含同原因故障和一个冷储备部件的可修复系统主算子性质

研究了含同原因故障的由两个不同型的平行部件和一个冷储备部件所组成的系统.通过选取空间并定义算子,将系统模型转化成抽象Cauchy问题.运用C_0半群和预解正算子理论,验证了系统主算子A为稠定的预解正算子,计算出了A的谱界为一c,同时得出了算子A的共轭算子及其定义域,最终利用共尾理论证得算子A的谱界和增长界相等,即为-c.     

参数不确定统一混沌系统的鲁棒分数阶比例-微分控制

针对含参数不确定的整数阶统一混沌系统, 提出一种鲁棒分数阶比例-微分(PD^μ)控制. 通过变换将受控统一混沌系统转换成等效被控对象及其等效控制器. 针对等效被控对象, 基于一种改进Monje-Vinagre方法并考虑到求解性能约束方程组的复杂度, 设计了鲁棒PD^μ控制器. 通过基于最小相角边界传递函数和最大增益边界传递函数的设计约束来保证受控统一混沌系统对参数不确定性的鲁棒性能. 数值仿真验证了所提出方法的有效性.     

单轴应变硅N沟道金属氧化物半导体场效应晶体管电容特性模型

电容特性模型是单轴应变硅金属氧化物半导体场效应晶体管(Si MOSFET)和电路进行瞬态分析、交流小信号分析、噪声分析等的重要基础. 本文首先建立了单轴应变Si NMOSFET 的16 个微分电容模型, 并将微分电容的仿真结果与实验结果进行了比较, 验证了所建模型的正确性. 同时对其中的关键性栅电容C_gg 与应力强度、偏置电压、沟道长度、栅极掺杂浓度等的关系进行了分析研究. 结果表明, 与体硅器件相比, 应变的引入使得单轴应变Si NMOSFET器件的栅电容增大, 随偏置电压、沟道长度、栅极掺杂浓度的变化趋势保持不变.     

多壁碳纳米管固相萃取净化气相色谱法分析蔬菜中有机氯和拟除虫菊酯农药残留

建立了多壁碳纳米管为吸附剂的固相萃取(SPE)净化、气相色谱-电子捕获检测(GC-ECD)测定蔬菜中6种有机氯和7种拟除虫菊酯农药的方法。采用双柱(HP-50和HP-1色谱柱)双检测器进行定性和定量分析。蔬菜样品采用乙腈提取,多壁碳纳米管SPE柱净化,正己烷溶解上样,丙酮-正己烷(7:3, v/v)洗脱,13种农药中有11种农药的添加回收率高于70%。将该净化方法用于荷兰黄瓜、卷心菜、红圣女果、奶油生菜、紫甘蓝、韭菜、大葱和洋葱等样品的净化,与弗罗里硅土SPE柱相比较,净化效果更好,表明多壁碳纳米管具有较强的吸附去除色素的能力,可以避免色素对测定的干扰。     

嵌入式碳纳米管石墨电极测定灯盏花素的研究

制备嵌入式多壁碳纳米管修饰石墨电极,利用循环伏安法(CV)研究灯盏花素在嵌入式多壁碳纳米管修饰石墨电极(ESCFE)上的电化学氧化行为,结果表明,灯盏花素在修饰电极上出现一对明显的准可逆氧化还原峰,峰电位分别为Epa=0.17 V和Epc=0.05 V(△E=0.12 V),峰电流分别为ipa=42.79μA,ipc=...     

New approach to differential equations with countable impulses

This paper provides a new approach to study the solutions of a class of generalized Jacobi equations associated with the linearization of certain singular flows on Riemannian manifolds with dimension n + 1.A new class of generalized differential operators is defined.We investigate the kernel of the corresponding maximal operators by applying operator theory.It is shown that all nontrivial solutions to the generalized Jacobi equation are hyperbolic,in which there are n dimension solutions with exponential...     

Existence of positive solutions for a general nonlinear eigenvalue problem

Let Ω R n be a bounded domain, H = L 2 (Ω), L : D(L) H → H be an unbounded linear operator, f ∈ C(■× R, R) and λ∈ R. The paper is concerned with the existence of positive solutions for the following nonlinear eigenvalue problem Lu = λf (x, u), u ∈ D(L), which is the general form of nonlinear eigenvalue problems for differential equations. We obtain the global structure of positive solutions, then we apply the results to some nonlinear eigenvalue problems for a second-order ordinary differential equation and a fourth-order beam equation, respectively. The discussion is based on the fixed point index theory in cones.     

The monotone method for controllability of the nonlinear evolution systems

In this paper,we study the controllability of the nonlinear evolution systems.We establish the controllability results by using the monotone operator theory.No compactness assumptions are imposed in the main results.We present an example to illustrate our results.     

带P-Laplacian算子的四点四阶奇异边值问题的对称正解

本文主要利用上下解方法和Schauder不动点定理,在更广泛的条件下研究了一类带PLaplacian算子的四点四阶奇异边值问题的对称正解的存在性.克服了对非线性微分算子[φp(u″)]″Fredholm抉择定理和极大值原理不能使用的困难,改进并推广了最近的一些已知结果.     

Completeness of the System of Root Vectors of 2 × 2 Upper Triangular Infinite-Dimensional Hamiltonian Operators in Symplectic Spaces and Applications

The authors investigate the completeness of the system of eigen or root vectors of the 2 × 2 upper triangular infinite-dimensional Hamiltonian operator H ₀. First, the geometrical multiplicity and the algebraic index of the eigenvalue of H ₀ are considered. Next, some necessary and sufficient conditions for the completeness of the system of eigen or root vectors of H ₀ are obtained. Finally, the obtained results are tested in several examples.