线上线下混合式实验教学模式的改革与探索

大学化学实验课程是培养材料、化学、化工等专业人才应用基本操作和理论解决实际问题的综合性实践训练环节。文章探讨了当前大学化学实验发展由于受到仪器设备大型化、专业化、成本大、更新快等因素限制出现瓶颈,设计了线上线下混合实验教学模式,进行相应的软硬件建设,并开展线上线下混合式实验教学模式的改革与探索。该教学模式具有良好的教学效果,并且可复制可推广,为创新人才的培养和实验教学的创新提供了有益的借鉴。     

Economical Access to Diverse Enantiopure Tetrahydropyridines and Piperidines Enabled by Catalytic Borrowing Hydrogen

We disclose herein a catalytic borrowing hydrogen method that enables an unprecedented, economical one-pot access to enantiopure tetrahydropyridines with minimal reagent use or waste formation. This method couples a few classes of readily available substrates with commercially available 1,3-amino alcohols, and delivers the valuable tetrahydropyridines of different substitution patterns free of N-protection. Such transformations are highly challenging to achieve, as multiple redox steps need to be realized in a cascade and numerous side reactions including a facile aromatization have to be overcome. Highly diastereoselective functionalizations of tetrahydropyridines also result in a general access to enantiopure di- and tri-substituted piperidines, which ranks the topmost frequent N-heterocycle in commercial drugs.     

Morphology Control over the Organic Nanoparticles of 1,3-Diphenyl-5-（9-anthryl）-2-pyrazoline

The organic nanoparticles of a blue-light-emitting molecule, 1,3-diphenyl-5-(9-anthryl)-2-pyrazuline, were prepared by reprecipitation method using acetonitrile as the solvent for the molecular precursor. Three morphologies, spherical, doughnut-shaped and cubic, could be observed on the silicon substrate forthe nanoparfides by the volume-controlled addition of acetonitrile. The evolution of particle morphology as a function of acetonitrile addition was attributed to the variation of the growth habits of the particles in the different environment. The nanoparticles exhibit the novel photoluminescence spectra as compared to those of monomer and the bulk crystals.     

双频光栅傅里叶变换轮廓术频谱混叠研究

讨论了用双频光栅方法对包含突变成份的物体产生的变形条纹进行傅里叶变换时,可能会出现频谱混叠问题.推出了低频光栅的频谱f1与高频光栅的频谱f2不相互混叠的条件,分析了探测器非线性会引起同一光栅间频谱发生混叠情况.考虑到通常情况下低频光栅频谱f1与高频光栅频谱f2的混叠起主要作用,因此在该情况下用计算机仿真与实验验证了:当f2<2f1时,f1与f2相互混叠,物体面形难以恢复;当f2>2f1时,f1与f2不相互混叠,物体面形恢复得很好.     

Numerical Simulation of Shear-Horizontal-Wave-Induced Electromagnetic Field in Borehole Surrounded by Porous Formation

Seismoelectric fieM excited by purely torsional loading applied directly to the borehole wall is considered. A brief formulation and some computed waveforms show the advantage of using shear-horizontal （SH） transverseelectric （TE） seismoelectric waves logging to measure shear velocity in a fluid-saturated porous formation. By assuming that the acoustic field is not influenced by its induced electromagnetic field due to seismoeleetric effect, the coupling governing equations for electromagnetic field are reduced to Maxwell equations with a propagation current source. It is shown that this simplification is valid and the borehole seismoelectric conversion efficient is mainly dependent on the electrokinetic coupling coefficient. The receivers to detect the conversion electromagnetic field and to obtain shear velocity can be set in the borehole fluid in the SH-TE seismoelectric wave log.     

半正二阶三点边值问题的解和正解

考察了非线性二阶三点边值问题的n个解和正解的存在性,其中允许非线性项有一个负的下界并且n是一个任意的自然数．主要结论表明该问题可以具有n个解或者正解,只要非线性项在某些有界集上的“高度”是适当的．     

α-混合序列下期望损失ES的两步核估计

期望损失(Expected Shortfall,ES)是当今最流行的金融资产风险管理的工具之一,是一个理想的一致性风险度量.本文在α-混合序列具有幂衰减混合系数条件下,用两步核估计估算风险度量ES的值,第一步是在险价值(Value at Risk,VaR)的核估计,第二步是ES的核估计.得到ES的核估计量的Bahadur表示,以及均方误差和渐近正态性的收敛速度.     

一类具非线性边值条件的微分方程的奇摄动问题

研究了一类非线性三阶微分方程的奇摄动问题.运用合成展开法构造了问题的形式渐近解,并运用不动点原理证明了原问题解的存在性及所得形式渐近解的一致有效性.     

用改进的十进制遗传算法确定土质边坡最危险滑面

基于瑞典圆弧法和简化Bishop条分法分析土质边坡的稳定性,以圆弧滑裂面与边坡面的左右交点的两个横坐标和以滑裂面圆心的纵坐标作为优化变量,采用了一种改进的十进制遗传算法对优化变量进行优化。这种改进的遗传算法是以简单的十进制遗传算法为基础,结合优体克隆操作、子体优生操作和多代调环操作。通过计算ACADS考核题验证,该方法有较强的自适应能力,具有收敛速度快、解的精度高和避免出现早熟等优点。