铜(Ⅱ)配位树状高分子的研究进展

介绍了一类由铜配位的树状高分子化合物的配位方式、制备及其催化性质。树状高分子与铜配位方式主要有分子内酰胺键的配位和分子末端的端氨基配位或端酯基配位。同时介绍了铜金属纳米粒子的制备及性质。发现随着其代数的增加，所形成纳米粒子的尺寸逐渐减小，而且大大降低了纳米粒子的团聚现象。并探讨了此类大分子在该领域中的研究和应用前景。     

亲水/疏水半互穿网络凝胶在直流电场作用下的响应

研究了一种亲水 疏水型半互穿网络水凝胶 (PAAc QPVPDgels)对直流电场的刺激应答 .该凝胶中的疏水型N 十二烷基聚 (4 乙烯吡啶 )溴化盐 (QPVPD)高分子链与亲水型聚丙烯酸水凝胶 (PAAc)网络通过物理缠绕复合 .由于疏水力和亲水力的共同作用 ,在接触电场下 ,该凝胶在阳极端发生消溶胀 ,疏水相互作用对消溶胀有一定的影响 ;在非接触电场下 ,该凝胶在弱碱性溶液中迅速向阴极方向弯曲 ,在弱酸性溶液中首先发生消溶胀 ,然后向阳极方向弯曲     

一个简单的能呈现二分岔现象的双分子反应模型

二分岔现象(pitchfork bifurcation)是非平衡非线性动力系统中最典型和最简单的分岔现象.1972年Schlogl提出了如下一个化学反应模型: A+2x?3X,X?B (1)假定组份A和B的浓度可由外界控制为恒定,在某些条件下该模型可呈现出二分岔现象.自那以后,Schlogl模型已成为人们研究非平衡相变时最广泛采用的理论模型,该模型对推动非平衡非线性现象的研究起了十分重要的作用.但从物理-化学的角度来看,该模型存在着如下一些问题:首先该模型涉及一个三分子自催化反应步骤,这种反应步骤在现实反应系统     

铝酸钠和含硅铝酸钠溶液结构和性质的研究

本文通过对铝酸钠和硅铝酸钠溶液的红外光谱、拉曼光谱、粘度、表面张力、丁达尔现象和聚沉等光谱和物理化学性质的研究测定,分析了硅在铝酸钠溶液中的行为.认为硅主要是取代Al-O-Al结构中的Al,形成Al-O-Si结构和Al-O-Si-O-Al-O结构等多种形式硅氧铝键以及由氢键相连的大分子结构.这种结构直接影响其物理化学性质,表现为随硅含量增加表面张力增加,粘度上升,具有丁达尔现象等.说明含硅铝酸钠溶液中存在大分子的胶性基团,属于无机高分子溶液,这种网络状"大分子"结构是硅铝酸钠溶液稳定的原因.     

Identification of Different Cobalt Nucleation on Glassy Carbon

The nucleation mechanisms of cobalt from sulfate solutions were studied by utilizing the electrochemical technique, chronoamperometry. It was found that the recorded current-time transients introduced from 1.0mol/L CoSO4 solution were complexes with unusual shapes. All characteristic features were identified as separate process. The instantaneous or progressive nucleation with 2D or 3D growth exists during the cobalt deposition, depending on the applied potentials.     

Anti-Controlling Codimension-2 Bifurcation of Discrete Dynamical Systems in 1 : 2 Resonance北大核心CSCD

从分岔反控制的角度设计了一套非线性反馈控制策略,来实现离散动力系统1∶2共振情形下余维二分岔的各种分岔解。首先,针对传统分岔准则在确定高余维分岔点时存在的局限性,建立了一个1∶2共振情形下的余维二分岔的新显式准则,基于这个显式准则通过设计线性控制增益来确保此类余维二分岔的存在性。然后,推导了1∶2共振的中心流形,并基于范式方法通过设计非线性控制增益,分析了1∶2共振情形下余维二分岔解的类型和稳定性。最后,以一个Arneodo-Coullet-Tresser映射为例,在指定的参数点处通过控制实现了具有1∶2共振分岔特性的各种分岔解,进一步验证了理论分析。     

Effects of Cone Angles on Nonlinear Vibration Responses of Functionally Graded Shells北大核心CSCD

The nonlinear vibration responses of functionally graded materials (FGMs) shells with different cone angles under external loads were studied. Firstly, the Voigt model was employed to describe the physical properties along the thickness direction of FGMs conical shells. Then, the motion equations were derived based on the 1st-order shear deformation theory, the von Kármán geometric nonlinearity and Hamilton’s principle. Next, the Galerkin method was applied to discretize the motion equations and the governing equations were simplified into a 1DOF nonlinear vibration differential equation under Volmir’s assumption. Finally, the nonlinear motion equations were solved with the harmonic balance method and the Runge-Kutta method, and the amplitude frequency response characteristic curves of the FGMs conical shells were obtained. The effects of different material distribution functions and different ceramic volume fraction exponents on the amplitude frequency response curves of conical shells were discussed. The bifurcation diagrams of conical shells with different cone angles, as well as time process diagrams and phase diagrams for different excitation amplitudes, were described. The motion characteristics were characterized by Poincaré maps. The results show that, the FGMs conical shells present the nonlinear characteristics of hardening springs. The chaotic motions of the FGMs conical shells are restrained and not prone to motion instability with the increase of the cone angle. The FGMs conical shell present a process from the periodic motion to the multi-periodic motion and then to chaos with the increase of the excitation amplitude. © 2022 Editorial Office of Applied Mathematics and Mechanics. All rights reserved.     

时滞对磁通耦合及化学耦合神经元分岔及同步的影响

以化学突触耦合神经元模型为基础,讨论了抑制性及兴奋性条件下达到同步的区别及同步的类型。并根据磁通耦合对神经元放电的影响,讨论了具有时滞、磁通耦合和化学耦合Morris-Lecar (ML)神经元模型的放电状态、分岔类型及其同步情况。发现具有磁通耦合和化学耦合ML神经元系统在不同参数下会产生丰富的逆倍周期分岔或加周期分岔行为。而时滞的引入,虽然可以增加系统的周期性,但同时也会破环系统同步。相反,适当的耦合强度能够增加同步。     

非对称碰撞约束下形状记忆合金梁的随机响应与分岔

形状记忆合金(SMA)是二十一世纪具有形状记忆效应的新型智能材料.针对具有非对称约束的SMA梁,本文构造了碰撞振动系统.在无碰撞和有碰撞两种情况下,利用随机平均法给出了近似解析结果.数值模拟作为验证解析结果的工具.结果表明,系统能量的概率响应曲线具有非光滑特性.当约束位置发生变化时,系统会出现随机P分岔和D分岔.     

Exact solutions for Belousov-Zhabotinskii reaction-diffusion system

Abstract. We consider the following simplified model for the Belousou-Zhabotinskii(B-Z)reaction: