Kinetics of catalytically activated duplication in aggregation growth

We propose a catalytically activated duplication model to mimic the coagulation and duplication of the DNA polymer system under the catalysis of the primer RNA. In the model, two aggregates of the same species can coagulate themselves and a DNA aggregate of any size can yield a new monomer or double itself with the help of RNA aggregates. By employing the mean-field rate equation approach we analytically investigate the evolution behaviour of the system. For the system with catalysis-driven monomer duplications, the aggregate size distribution of DNA polymers a_k(t) always follows a power law in size in the long-time limit, and it decreases with time or approaches a time-independent steady-state form in the case of the duplication rate independent of the size of the mother aggregates, while it increases with time increasing in the case of the duplication rate proportional to the size of the mother aggregates. For the system with complete catalysis-driven duplications, the aggregate size distribution a_k(t) approaches a generalized or modified scaling form.     

NO3自由基与HNO及HONO反应机理研究

有研究显示NO3自由基会在RDX热解过程中形成,然而实验中却始终未有发现.本文首次通过量子化学方法研究了NO3自由基分别与RDX两种热解产物HNO及HONO的反应,并利用CCSD(T)/6-311++G(d,p)方法对反应势垒进行了精确计算.计算结果显示,NO3+HNO反应为无势垒反应,且放出大量热量,预示该反应极易发生.这为NO3自由基始终没有在RDX热解实验中被观察到提供了一种解释.     

COMSOL软件在高中物理教学中的应用——以“磁场和磁感线”为例

简要介绍计算机仿真软件COMSOL在教学中的应用优势,并以高中物理"磁场和磁感线"为例,展示了如何高效利用该软件辅助中学物理教学,以帮助学生掌握物理概念,建立空间模型,培养思维能力.     

Evolution behavior of catalytically activated replication-decline in a coagulation process

We propose a catalytically activated replication-decline model of three species, in which two aggregates of the same species can coagulate themselves, an A aggregate of any size can replicate itself with the help of B aggregates, and the decline of A aggregate occurs under the catalysis of C aggregates. By means of mean-field rate equations, we derive the asymptotic solutions of the aggregate size distribution ak（t） of species A, which is found to depend strongly on the competition among three mechanisms： the self-coagulation of species A, the replication of species A catalyzed by species B, and the decline of species A catalyzed by species C. When the self-coagulation of species A dominates the system, the aggregate size distribution a~（t） satisfies the conventional scaling form. When the catalyzed replication process dominates the system, ak（t） takes the generalized scaling form. When the catalyzed decline process dominates the system, ak（t） approaches the modified scaling form.     

一维铁磁材料光子晶体的光学传输特性

利用光学传输矩阵方法,模拟计算了由铁磁材料组成的一维光子晶体的光学传输特性.研究了能带结构随介质层厚度h(O ≤h≤0.5λ0 λ0=1.2×10-6m)变化的规律,并与相同周期结构的普通光子晶体的传输特性进行了比较.结果表明,当O.15λ0＜h＜0.165λ0时,铁磁光子晶体的带隙宽度略小于普通光子晶体的带隙宽度;在h取其他值时铁磁光子晶体的带隙宽度远远大于普通光子晶体的带隙宽度,并且在h=0.25λ0时存在最大值.这种结构的光子晶体通过掺杂有望在多通窄带滤波技术中得到广泛的应用.     

数字电路基础分层次教学模式的探究

“ 数字电路”是高等院校理工科电信等专业学生的一门重要基础课, 在学生的培养过程中起着十分重 要的作用. 该门课程理论性和实用性都很强, 学生不易掌握. 本文以提高高校“ 数字电路基础”课程的教学质量为目 标, 对课程的教学模式提出改革思路, 对该课程分层次教学模式进行探究. 研究中结合物理专业特点以及自己的实 际教学经验, 通过在教学中探索和对不同年级学生进行问卷调查, 结果显示对“ 数字电路基础”课程在学生中进行 走班分层的教学模式是切实可行的