2,7-二芳基呫吨螺芴二醇衍生物的合成

以2,7-二溴-9-芴酮、间苯二酚和苯硼酸的衍生物为原料,经过环化、羟乙基化和Suzuki偶联等3步反应,设计并合成了一系列2,7-芳基呫吨螺芴二醇衍生物,通过红外光谱、核磁光谱（¹H NMR, ¹³C NMR）、元素分析等表征了化合物的结构。折光率和紫外可见光谱测试结果表明:与2,7-无取代基的呫吨螺芴二乙醇衍生物相比,目标化合物具有更高的折光率(1.66~1.68)和良好的透光率,有望作为聚碳酸酯光学树脂的二醇单体,应用于光学透镜、光学膜等领域。     

Modeling and staged assessments of the controllability of spread for repeated outbreaks of COVID-19

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) has been causing an outbreak of a new type of pneumonia globally, and repeated outbreaks have already appeared. Among the studies on the spread of the COVID-19, few studies have investigated the repeated outbreaks in stages, and the quantitative condition of a controllable spread has not been revealed. In this paper, a brief compartmental model is developed. The effective reproduction number (ERN) of the model is interpreted by the ratio of net newly infectious individuals to net isolation infections to assess the controllability of the spread of COVID-19. It is found that the value of the ERN at the inflection point of the pandemic is equal to one. The effectiveness of the quarantine, even the treatment, is parametrized in various stages with Gompertz functions to increase modeling accuracy. The impacts of the vaccinations are discussed by adding a vaccinated compartment. The results show that the sufficient vaccinations can make the inflection point appear early and significantly reduce subsequent increases in newly confirmed cases. The analysis of the ERNs of COVID-19 in the United States, Spain, France, and Peru confirms that the condition of a repeated outbreak is to relax or lift the interventions related to isolation and quarantine interventions to a level where the ERN is greater than one.

     

三嗪类化合物溶解度参数及毒性构—效关系

测定了１２种三嗪类化合物的水溶解度，辛醇水分配系数和对发光菌的毒性，并用分子连结性指数建立了预测三嗪类化合物的溶解度，辛醇水分配系数及对发光菌毒性的定量结构活性相关方程，其中１０种化合物献中未见报道。e     

光波导三向力触觉传感技术及信号处理

本文阐述了一种新的光波导型三向力触觉传感器的工作原理和基本结构,并设计了实验系统。这种传感器由一个橡胶垫和一个光波导路等组成,在橡胶垫的一侧制作圆柱触头阵列,在其另一侧制作圆锥触头阵列,使得每个圆柱触头下面分布2×2个圆锥触头。圆柱触头与施力的物体接触,而圆锥触头与光波导板接触。施加到圆柱触头上的力的三个分量可以通过该圆柱触头所对应的2×2个圆锥触头与光波导板接触时溢出的光斑面积确定。通过CCD摄取此光斑送入计算机进行图象处理,从而可求出光斑面积大小。实验结果显示了力的三个分量能通过圆锥触头的四个接触面积求出。     

CDS器件在TDI-CCD视频信号处理中的应用

本文是对国家863-2计划中某项目的部分工作所做的总结。文中对CCD的噪音和新型TDI-CCD输出视频信号的特性进行了分析,提出了对于各种噪音的处理方法,尤其详细介绍了采用相关双采样(CDS)技术处理kTC噪音和复位噪音的方法,并通过实验进行了验证,最后分析了系统的信噪比。     

含嘧啶环的双冠醚(Ⅳ)

前文已报道由啶环桥联两个苯并冠醚的双冠醚的合成与性质。由于嘧啶环的刚性较大,能把两个冠醚单元固定在有效地协同作用位置,因此以它们作中性载体的离子选择性电极具有较好的选择性。为了进一步研究这类双冠醚的性质,我们合成了四种嘧啶环桥联两个脂肪族冠醚的双冠醚,并经元素分析、IR、′HNMR鉴定。     

Global dynamics of a pipe conveying pulsating fluid in primary parametrical resonance: Analytical and numerical results from the nonlinear wave equation

The chaotic dynamics of nonlinear waves in the harmonic-forced fluid-conveying pipe in primary parametrical resonance, is explored analytically and numerically. The multiple scale method is applied to obtain an equivalent nonlinear wave equation from the complicated nonlinear governing equation describing the fluid conveyed in a pipe. With the Melnikov method, the persistence of a heteroclinic structure is shown to be satisfied and its condition is given in functional form. Similarly, for the heteroclinic orbit, using geometric analysis, a condition function of the stable manifold is derived for the orbit to return to the stable manifold from the saddle point. The persistent homoclinic structures and threshold of chaos in the Smale-horseshoe sense are obtained for the fluid-conveying pipe under both conditions, indicating how the external excitation amplitude can change substantially the global dynamics of the fluid conveyed in the pipe. A numerical approach was used to test the prediction from theory. The impact of the external excitation amplitude on the nonlinear wave in the fluid-conveying pipe was also studied from numerical simulations. Both theoretical predications and numerical simulations attest to the complex chaotic motion of fluid-conveying pipes.     

Stationary solutions of non-autonomous Maxwell–Dirac systems

The Maxwell–Dirac system describes the interaction of a particle with its self-generated electromagnetic field. In this paper, we study the existence of least energy stationary solutions for non-autonomous Maxwell–Dirac system with a nonlinear term in (3+1)$(3+1)$-Minkowski space–time via variational methods. This problem is strongly indefinite and presents a lack of compactness. To overcome these difficulties, we will use the linking and concentration compactness arguments.     

中间补气的双级压缩热泵系统性能的实验研究

以滚动活塞压缩机为例,搭建了带中间补气的单机双级压缩热泵系统,对中间补气参数对系统制热性能的影响进行实验研究。实验结果表明:中间补气与不补气相比,制热量增加5～8%,制热COP提高3～7%。能降低排气温度8～14℃,压缩机效率提高5～12%,高压级容积效率提高4～9%。为今后压缩机设计和热泵系统运行提供了实验数据和经验参考。     

Four-wing hyperchaotic attractor generated from a new 4D system with one equilibrium and its fractional-order form

In this paper, a new simple 4D smooth autonomous system is proposed, which illustrates two interesting rare phenomena: first, this system can generate a four-wing hyperchaotic and a four-wing chaotic attractor and second, this generation occurs under condition that the system has only one equilibrium point at the origin. The dynamic analysis approach in the paper involves time series, phase portraits, Lyapunov exponents, bifurcation diagram, and Poincaré maps, to investigate some basic dynamical behaviors of the proposed 4D system. The physical existence of the four-wing hyperchaotic attractor is verified by an electronic circuit. Finally, it is shown that the fractional-order form of the system can also generate a chaotic four-wing attractor.