Chemical oscillations

A chemical reaction is usually thought of as coming together of reactant molecules to form products. The concentrations of initial components (reactants) decrease, and concentrations of products increase until they reach a well defined state: the equilibrium. This process is accompanied by a decrease of the system free energy (compared at constant pressure and temperature), until it reaches a minimum in the equilibrium. Thus, it follows from the nature of the law of mass-action that every simple reaction approaches its equilibrium asymptotically, and the evolution of any physico-chemical system leads invariably to the steady state of maximum disorder in the universe. Normally, chemical systems approach equilibrium in a smooth, frequently exponential relaxation. Under special circumstances, however, coherent behavior such as sustained oscillations are observed and the oscillations of chemical origin have been present as long as life itself. Such reactions can be studied using mathematical models, the Lotka-Volterra model being the earliest and the simplest one.     

The director of education as a leader of pedagogical issues: a study of leadership in municipal educational sector activities

The purpose of this article is to increase our knowledge about the role that directors of education play as leaders of educational activities. For its analytical framework, the study uses the qualitative research approach known as phenomenography and examines the study's findings against the rationalist perspective, against systems theory and against tight and loosely-coupled systems. On the issue of accountability, the study shows that while the directors were perceived to be accountable for mismanagement of finances, being accountable for student results was not something that worried the directors participating in this study.     

广义耦合Hirota-Satsuma KdV方程组的对称约化和精确解

利用修正的CK直接方法,得到广义耦合Hirota-Satsuma KdV方程组的经典李点对称,并利用对称得到该方程的一些相似约化和新的精确解,同时,建立了该方程组的新、旧解之间的关系,从而推广了本文所得的新解.     

基于耦合网络的社交网络舆情传播模型研究

[目的]为了研究社交网络以及研究微博网络与微信网络之间舆情的传递过程。[方法]利用无标度有向网络和BA网络分别模拟微博网络和微信网络环境,通过特定的连接关系设计了耦合网络载体,在SEIR模型的基础上,充分分析了用户的传播心理,考虑到了个体具有兴趣衰减效应以及记忆效应等特征,构建了基于耦合网络的社交网络舆情传播模型。[结果]实验结果表明,构建的双层社交网络舆情传播模型能较好地反映现实生活中的舆情传播过程,用户在多层社交网络之间的互动加速了舆情信息的流动,扩大了舆情信息的影响力,层间传播阈值的控制是管理多层社交网络舆情传播的关键。     

A Novel Multivalued Associative Memory System *

通过适当控制参数,全局耦合映射模型能够从混沌搜索演化到若干稳定的周期轨道．这种特性可用于联想记忆和优化．本文在修正的ＧＣＭ模型（ＳＧＣＭ）基础上提出了一种新的多值模式相关学习规则可有效地用于灰度图像的联想记忆．最后对回忆的效果进行了分析．     

关于混合单调算子的藉合不动点定理

在本中，献[1]的定理1及其推论得到了推广。     

任意信号输入完全耦合互感电路的暂态过程

利用等效电路方法、戴维南定理、卷积积分推导出任意信号输入完全耦合互感电路的哲态过程的一般表示式,并给出了应用实例。     

天山雪莲花中稀土元素的电感耦合等离子质谱法分析

建立了一种电感耦合等离子体质谱法测定天山雪莲中痕量稀土元素的方法．利用该方法分析了国家标准物质（GBW07603）中的稀土元素,结果与标准值一致．该方法被用于分析天山雪莲实际样品中的稀土元素,结果令人满意．     

Torsional Oscillation Characteristics of Rotary Shafts Based on Torsion and Bending Coupled Vibration

THE TORSIONAL OSCILLATION CHARACTERISTICS ON THE BENDING AND TORSION COUPLED VIBRATION OF ROTARY SHAFT SYSTEM WERE INVESTIGATED USING THE ELASTO-DYNAMIC THEORY AND OTHER MATHEMATIC METHODS, SUCH AS DIFFERENCE APPROACH, FOURIER TRANSFORM, AND WAVELET TRANSFORM. IT IS CONCLUDED THAT MASS ECCENTRICITY AND OTHER EXCITING MODALITIES AFFECT THE BENDING AND TORSION COUPLED VIBRATION OF ROTARY SHAFTS. TORSIONAL VIBRATION CAUSED BY BENDING VIBRATION FEATURES LINEARITY ALONG WITH THE CHANGE OF AMPLITUDE OF BENDING VIBRATION. MEANWHILE, ENERGY SPECTRUM CONCENTRATES ON HIGH FREQUENCY ARE-A WITH THE WAVELET ANALYSIS.     

电感耦合等离子体质谱法测定小麦中的重金属元素

采用电感耦合等离子体质谱法测定小麦中铅、砷、铬、镉、铜、锌、铁和锰8种重金属元素.用微波消解法对样品进行消解,用ICP-MS对消解液进行检测.用加标回收率试验考察了方法的准确性,结果表明,所测元素在标准溶液浓度范围内呈线性关系,相关系数均大于0.9990.方法的检出限在0.01025~4.547 mg/kg之间,相对标准偏差均小于3.89%,加标回收率在90.70%~109.9%之间.此方法快速准确、检出限低、灵敏度高,适用于小麦中8种重金属元素的测定.