Stability of piecewise-linear models of genetic regulatory networks

This paper investigates the stability of the equilibria of the piecewise-linear models of genetic regulatory networks on the intersection of the thresholds of all variables. It first studies circling trajectories and derives some stability conditions by quantitative analysis in the state transition graph. Then it proposes a common Lyapunov function for convergence analysis of the piecewise-linear models and gives a simple sign condition. All the obtained conditions are only related to the constant terms on the right-hand side of the differential equation after bringing the equilibrium to zero.     

有leader的二阶动态多智能体网络的L2-L∞控制

考虑系统噪声和时滞,利用L2-L∞控制理论研究了有leader的二阶定拓扑多智能体系统的协调一致问题.工程应用中控制输出的极大值经常需控制在一定范围内,并且考虑系统对位置变量和速度变量限制的范围不同,分别针对位置和速度的控制输出设计了加权系数;进而建立了多智能体系统的数学模型.对有时滞和无时滞的两种网络拓扑,利用李亚普诺夫函数,分析了多智能体系统在满足L2-L∞性能指标要求下,followers和leader的位置与速度的一致问题.并且以双线性矩阵不等式的形式,分别给出了有时滞和无时滞网络系统能够达到一致的条件.最后仿真结果验证了所获结果的有效性.     

苯甲酰水杨酸铽的合成与发光特性研究

合成了一类以苯甲酰水杨酸(Benzoyl Salicylic Acid,BSA)为配体的稀土铽配合物,将导电高分子材料PVK引入到配合物中,制成了结构为ITO／PVK：Tb(BSA)4／LiF／Al的电致发光器件。并对该配合物的吸收特性及电致发光和光致发光性能进行了研究,实验数据表明,在PVK与Tb(BSA)4之间存在着能量传递,在电致发光中,PVK的发光完全被抑制,这与光致发光的表现不同,这是由于两种发光(光致和电致)机理不同造成的。章同时比较了几种不同PVK掺杂浓度对于器件性能的影响。     

时间分辨荧光免疫分析高灵敏检测嗜水气单胞菌

建立了生物素-链霉亲和素时间分辨荧光免疫分析（BAS-TRFIA）高灵敏检测嗜水气单胞菌的新方法.以兔抗IgG包被微孔板,加入嗜水气单胞菌菌株B18和生物素化IgG,生成的夹心复合物用Eu³⁺-链霉亲和素作为示踪物,Eu³⁺可与离解增强液形成时间分辨荧光（TRF）,通过TRF值对病原菌定量.方法的检测限为1.0×10² cfu/mL,在1.0×10~1.0×10⁶ cfu/mL范围内线性良好,相关系数0.9716.用该法检测时,不同来源的嗜水气单胞菌以及其它气单胞菌均呈阴性.板内和板间的变异系数分别小于5.00%和9.00%.所有相关检测试剂37℃恒温放置6 d后,检测性能无明显改变.对60份人工感染的美洲鳗鲡组织样品,包括肝、肾、肠、鳃和肌肉等组织进行检测,阳性检测率为98.33%.结果表明,BAS-TRFIA法检测嗜水气单胞菌,灵敏度高、特异性好、操作简便,该方法为水产养殖病原菌检测提供了新的思路.     

Discrete element crowd model for pedestrian evacuation through an exit

A series of accidents caused by crowds within the last decades evoked a lot of scientific interest in modeling the movement of pedestrian crowds. Based on the discrete element method, a granular dynamic model, in which the human body is simplified as a self-driven sphere, is proposed to simulate the characteristics of crowd flow through an exit. In this model, the repulsive force among people is considered to have an anisotropic feature, and the physical contact force due to body deformation is quantified by the Hertz contact model. The movement of the human body is simulated by applying the second Newton's law. The crowd flow through an exit at different desired velocities is studied and simulation results indicated that crowd flow exhibits three distinct states, i.e., smooth state, transition state and phase separation state. In the simulation, the clogging phenomenon occurs more easily when the desired velocity is high and the exit may as a result be totally blocked at a desired velocity of 1.6 m/s or above, leading to faster-to-frozen effect.     

Spatial chirp in Ti:sapphire multipass amplifier

The spatial chirp generated in the Ti:sapphire multipass amplifier is numerically investigated based on the onedimensional(1D) and two-dimensional(2D) Frantz–Nodvik equations. The simulation indicates that the spatial chirp is induced by the spatially inhomogeneous gain, and it can be almost eliminated by utilization of proper beam profiles and spot sizes of the signal and pump pulses, for example, the pump pulse has a top-hatted beam profile and the signal pulse has a super-Gaussian beam profile with a relatively larger spot size. In this way, a clear understanding of spatial chirp mechanisms in the Ti:sapphire multipass amplifier is proposed, therefore we can effectively almost eliminate the spatial chirp and improve the beam quality of a high-power Ti:sapphire chirped pulse amplifier system.     

短纤维增强复合材料破坏过程的数值模拟

利用一个材料破坏过程分析程序ＭＦＰＡ＾２Ｄ系统,研究了短纤维增强复合材料的破坏过程,研究表明,对于非均匀脆性材料而言,纤维与基体的强度、弹性模量经级纤维的弹塑性性质对宏观材料的强度和韧性有很大的影响,数值模拟再现了短纤维增强复合材料的变形、破坏全过程,包括纤维的止裂与桥连作用及微裂纹的萌生、扩展直至最宏观贯通。     

镥铕共发光时间分辨荧光免疫法检测嗜水气单胞菌

建立了共发光时间分辨荧光免疫检测嗜水气单胞菌的新方法,以嗜水气单胞菌菌株B11包被微孔板,与Eu3+标记的兔抗IgG免疫反应后,加入含有共发光离子Lu3+的解离增强剂,由于Eu3+和Lu3络合物的共发光效应,时间分辨荧光大大增强,有效放大了检测信号,提高了检测灵敏度.优化了共发光体系的条件,方法的检出限为1.0×103...     

用超导转变点和气体三相点温度监测标准铑铁电阻温度计

用 SRM767a 超导转变固定温度点器件中的六个 T_c 点和密封气体三相点瓶复现的三个气体三相点在 0.5—25K 间对标准铑铁电阻温度计做九点监测,并用多项式R=sum from k=0 to 6 bk[ln(T+9)]~k做最小二乘法拟合,发现受验证的16支温度计对分度值的偏差≤2mK.     

使用NBS的SRM 767a复现六个超导固定点的温度

用精密互感电桥在稀释致冷机上复现了NBS SRM767a 器件中的全部六个超导固定点温度,即Nb、Ph、In、Al、Zn和Cd的超导转变温度T_c。给出了每个点的互感变化△M和转变宽度w,并同三支锗电阻温度计的示值作了比较。