An Anti-Control Scheme for Spiral under Lorenz Chaotic Signals

The Fitzhugh-Nagumo (FHN) equation is used to generate spiral and spatiotemporal chaos. The weak Lorenz chaotic signal is imposed on the system locally and globally. It is found that for the right chaotic driving signal,spiral and spatiotemporal chaos can be suppressed. The simulation results also show that this anti-control scheme is effective so that the system emerges into the stable states quickly after a short duration of chaotic driving (about 50 time units) and the continuous driving keeps the system in a homogeneous state.     

Evolution of Spiral Waves under Modulated Electric Fields

Spirals generated from the excitable media within the Barkley model is investigated under the gradient electric fields by a numerical simulation. The spiral drift and spiral break up are observed when the amplitude of the electric fields is modulated by a constant signal or a chaotic signal. It is also verified that, even in the presence of the white noise, the whole system can reach homogeneous states after the spiral breakup, by using an adaptive strategy.     

13.5—14.6MeV中子能区锗的同位素反应截面的测量

报道了在13.5—14.6MeV中子能区用活化法测得的⁷⁶Ge(n,2n)⁷⁵Ge, ⁷⁰Ge(n,2n)⁶⁹Ge, ⁷⁰Ge(n, p)⁷⁰Ga, ⁷²Ge(n,p)⁷²Ga, ⁷³Ge(n,p)⁷³Ga, ⁷²Ge(n,α)^69mZn和⁷⁴Ge(n, α)^71mZn的反应截面值. 中子注量用⁹³Nb(n,2n)^92mNb反应截面得到. 单能中子由T(d,n)⁴He反应获得. 同时还列举了已收集到的文献值以作比较.     

Stabilization of spiral wave and turbulence in the excitable media using parameter perturbation scheme

This paper proposes a scheme of parameter perturbation to suppress the stable rotating spiral wave, meandering spiral wave and turbulence in the excitable media, which is described by the modified Fitzhug-Nagumo （MFHN） model. The controllable parameter in the MFHN model is perturbed with a weak pulse and the pulse period is decided by the rotating period of the spiral wave approximatively. It is confirmed that the spiral wave and spiral turbulence can be suppressed greatly. Drift and instability of spiral wave can be observed in the numerical simulation tests before the whole media become homogeneous finally.     

染料敏化太阳能电池光敏剂卟啉儿茶酚的密度泛函和含时密度泛函研究

用密度泛函理论的杂化密度泛函B3LYP方法研究了太阳能电池光敏荆5,10,15.三苯基-20-(3,4-二羟基苯)卟啉(卟啉儿荼酚,TPP-cat)的几何结构、电子结构、IR和Raman特性.用自然键轨道方法分析了电荷布居和成键性质.计算结果表明,最强的IR吸收峰位于1175.81 cm-1处,最强的Raman活性位于1587.18 cm-1处.采用含时密度泛函计算了TPP-cat在水溶液中的电子吸收谱,其Soret带和Q带均指认为π→π*跃迁,在大约354 cm-1处的跃迁与一个光诱导分子内电荷转移过程有关.     

(Li3N)n(n=1-5)团簇结构与性质的密度泛函研究

用密度泛函理论(DFT)的杂化密度泛函B3LYP方法在6-31G*基组水平上对(Li3N)n(n=1-5)团簇各种可能的构型进行儿何结构优化,预测了各团簇的最稳定结构.并对最稳定结构的振动特性、成键特性、电荷特性等进行了理论研究.结果表明,(Li3N)n(n=1-5)团簇中N原子的配位数以4,5较多见,"Li-Li键长为0.210-0.259 nm,Li原子在桥位时Li-N键长为0.185-0.204 nm,Li原子在端化时Li-N键长为0.172-0.178nm;团簇中N原子的平均自然电荷为-2.01 e,Li原子的平均自然电荷为 0.67e;Li3N,(Li3N)5团簇有相对较高的动力学稳定性.     

14MeV钕的同位素反应截面的测量

报道了在13.5—14.6MeV中子能区用活化法以⁹³Nb(n,2n)^92mNb反应截面为中子注量标准测得的¹⁵⁰Nd(n,2n)¹⁴⁹Nd,¹⁴⁸Nd(n,2n)¹⁴⁷Nd和¹⁴²Nd(n,2n)¹⁴¹Nd的反应截面值.由13.5±0.2,14.1±0.1和14.6±0.2MeV中子引起的¹⁵⁰Nd(n,2n)¹⁴⁹Nd反应截面值分别为2037±85,1737±68,1657±65mb,¹⁴⁸Nd(n,2n)¹⁴⁷Nd反应截面值分别为1394±58,1416±54,1956±76mb,^{142Nd(n,2n)141Nd反应截面值分别为1501±59,1623±62,1764±111mb.单能中子由T(d,n)4He反应获得.文中还收集了已发表的数据以作比较.}     

Si6N2团簇结构与性质的密度泛函理论研究

用密度泛函理论(DFT)中的杂化密度泛函B3LYP方法,在6-31G(d)的水平上对Si6N2团簇的可能结构进行了几何结构优化和电子结构计算,得到了16个可能的异构体.Si6N2团簇的最稳定结构是有4个Si-N键和4个Si-Si键的三维结构.自然键轨道方法分析成键性质的结果表明,Si-N键中Si原子向N原子有较大的电荷转移,因此Si-N原子间有较强的电相互作用;最强的IR和Raman谱峰分别位于1359.14cm-1和1366.29cm-1处;并计算了Si6N2团簇的最稳定结构的极化率和超极化率.     

160Gd(n,2n)159Gd和158Gd(n,p)158Eu反应截面测量

报道了在13.5—14.6MeV中子能区用活化法测得的¹⁶⁰Gd(n,2n)¹⁵⁹Gd和¹⁵⁸Gd(n,p)¹⁵⁸Eu的 反应截面值. 中子注量用⁹³Nb(n, 2n)⁹²m Nb反应截面得到. 由(13.5±0.2)MeV,(14.1±0.1)MeV和(14.6±0.2)MeV中子引起的¹⁶⁰Gd(n, 2n) ¹⁵⁹Gd反应截面值分别为(1940±83)mb, (2324±92)mb和(1983±77)mb, ¹⁵⁸Gd(n, p) ¹⁵⁸Eu反应截面值分别为(1.9±0.1)mb, (2.1±0.1)mb和(3.5±0.1)mb. 单能中子由T(d, n)⁴He反应获得.文中还列举了已收集到的数据以作比较.     

线性反馈抑制螺旋波

研究了激发介质FitzhughNagumo方程中螺旋波的控制问题.基于稳定性和自适应理论,对系统格点变量进行采样,将采样变量与外界标准的周期信号和稳定信号进行线性作差,进一步将误差线性反馈到系统(局部反馈和全局反馈)中,当系统达到稳定均匀态,控制器自动关闭.并研究了噪声对该方法的影响.数值计算表明,选择不同的控制区域和外部标准信号,可将螺旋波抑制,系统很快达到均匀态,螺旋波转化成靶波或者形成新的斑图,控制器对噪声有一定鲁棒性.