液相色谱-串联质谱法筛查原多甲藻酸毒素及其代谢产物

建立了原多甲藻酸毒素(azaspiracids,AZAs)及其代谢产物的液相色谱-串联质谱检测方法,考察了目标代谢产物检测方法和非目标多离子检测方法,将二级质谱图与标准品谱库进行比对,从而获得高精准定性。通过对产毒藻、蓄积代谢实验样品和实际阳性样品综合分析,共检出11种AZAs,其中包括AZA-2,3,6,11,12,16,17,28和36,以及AZAs的谷胱甘肽结合型代谢产物。结果发现,目标代谢产物检测法可无偏差地筛出常规代谢物,而且对低浓度代谢产物表现出更佳的响应。本方法重现性好,数据分析简单,对操作人员的专业要求不高,更适合AZAs的监控要求。     

从文物中学化学——铁、铜性质主题式复习教学设计与实施

选择"铁、铜性质主题式复习"为案例,以铁器和铜器文物为主题背景,将铁、铜性质的复习与文物知识的介绍结合起来,使学生在学习过程中主动建构知识,在复习化学知识的同时,接触了一些文物知识,拓宽了视野,激发了学习兴趣。     

深水钻井隔水管在平台升沉运动下的参激振动响应分析

建立了深水钻井隔水管在平台升沉运动作用下的参激振动控制方程;利用振型叠加法将控制方程转化成马蒂厄方程形式,并用摄动法对马蒂厄方程进行求解;考虑海水的阻尼作用,得到了隔水管参激振动的马蒂厄不稳定区。最后对参激振动方程进行了实例求解,得到了参激振动下的隔水管位移,并在此基础上对参激振动的稳定性及隔水管强度进行了分析。结果表明:在给定的平台升沉周期与升沉振幅条件下,隔水管外径、壁厚、顶张力的变化均有可能引发隔水管产生参激共振;在不产生参激共振的情况下,隔水管Mises应力随隔水管外径与壁厚的增大而减小,随顶张力与升沉补偿装置轴向刚度系数的增大而增大;最大Mises应力均出现在隔水管顶部,沿水深近似成线性分布。     

近红外定性分析模型的稳健性与适应性分析

研究了近红外定性分析中模型的稳健性与适应性问题。讨论了单独建模延长建模周期对模型性能的影响,结果显示这种方法可以显著提高模型的稳健性,同时对模型的台间适应性也有所提升,但提升作用有限;研究了不同仪器联合建模的方法对模型性能的影响,该方法不仅可以显著提高模型的适应性,而且可以有效提高模型的稳健性。对比单独建模,可以缩短建模时间,减少模型建立的工作量;延长模型的适用期限,提高建模效率。结果表明,对模型适应性的测试,单独建模其正确识别率较低,不能满足应用的要求,而多台仪器联合建模可以达到90%以上,提升效果明显;对模型稳健性的测试,联合建模也能得到相比单独建模更好的模型识别效果,具有很好的应用价值。     

基于稳定性分析的应急物资储备策略研究

应急物资实物代储方式是有效降低应急物流成本和实现应急物资快速筹集的重要举措。针对政府直接储备应急物资所带来的采购和管理成本过高、巨额资金占用、物资性能降低以及因管理不善造成的应急物资浪费等问题,本文本着互利合作的原则,借助种群共生理论构建政府与应急物资代储企业之间的合作共生关系,并通过构建数学模型分析了政府与实物代储企业满足共生平衡点的稳定性条件,以解决政府在限制支付条件下如何选择应急物资代储企业的问题,为政府制定应急物资储备策略提供决策依据。     

Stability Analysis for Car Following Model Based on Control Theory

Stability analysis is one of the key issues in car-following theory. The stability analysis with Lyapunov function for the two velocity difference car-following model （for short, TVDM） is conducted and the control method to suppress traffic congestion is introduced. Numerical simulations are given and results are consistent with the theoretical analysis.     

Stability analysis and control synthesis of uncertain Roesser-type discrete-time two-dimensional systems

We study the stability analysis and control synthesis of uncertain discrete-time two-dimensional(2D) systems.The mathematical model of the discrete-time 2D system is established upon the well-known Roesser model,and the uncertainty phenomenon,which appears typically in practical environments,is modeled by a convex bounded(polytope type) uncertain domain.The stability analysis and control synthesis of uncertain discrete-time 2D systems are then developed by applying the Lyapunov stability theory.In the processes of stability analysis and control synthesis,the obtained stability/stabilzaition conditions become less conservative by applying some novel relaxed techniques.Moreover,the obtained results are formulated in the form of linear matrix inequalities,which can be easily solved via standard numerical software.Finally,numerical examples are given to demonstrate the effectiveness of the obtained results.     

Impacts of higher-order dispersions and saturable nonlinearities on modulation instability in negative-refractive metamaterials

On the basis of the standard linear stability analysis and Drude electromagnetic model,the impacts of higher-order dispersions and three kinds of typical saturable nonlinearities on modulation instability(MI) have been analyzed and calculated for negative-refractive metamaterials(MMs).Our results show that the MI gain spectra consist of only one spectral region instead of one or two regions in ordinary materials,which may be close to or far from the zero point.Particularly,the spectrum far from the zero point has a high cut-off frequency but a narrow spectral width,which is obviously beneficial to the generation of high-repetition-rate pulse trains.Moreover,MI characteristics here will vary with the normalized angular frequency which can be modified by adjusting the structures of negative-refractive MMs,signifying the controllability of bistable solitons and MI based applications.The effects of saturable nonlinearities are similar to those in ordinary materials.     

瞬态问题稳定性及弥散分析的无网格RKPM配点法研究

介绍了基于强形式的RKPM配点法求解瞬态动力问题的算法,并提出了采用RKPM配点法,配合时间域中心差分求解二阶波动方程的稳定性评价方法,并通过数值算例验证了此方法的正确性．此评价方法可以方便有效地评估出实际计算时的临界时间步长．通过数值算例比较可知,实际算例的计算临界时间步长与本评价方法,所预测的临界时间步长结果非常接近．给出了如何合理地选择RKPM形函数支撑域的建议．最后与径向基函数配点法进行了对比研究．     

A New Car Following Model： Comprehensive Optimal Velocity Model

In this paper, we present a new car-following model, i.e. comprehensive optimal velocity model (COVM), whose optimal velocity function not only depends on the following distance of the preceding vehicle, but also depends on the velocity difference with preceding vehicle. Simulation results show that COVM is an improvement over the previous ones theoretically. Then, the stability condition of the model is obtained by the linear stability analysis, which has shown that the model could obtain a bigger stable region thanprevious models in the phase diagram. Through the nonlinear analysis, the Burgers, Korteweg-de Vries (KdV) and modified KdV (mKdV) equations are derived for the triangular shock wave, the soliton wave, and the kink-antikink soliton wave. At the same time, numerical simulations are also carried out to show that the model could simulate these density waves.