定常的热传导-对流问题的Galerkin/Petrov最小二乘混合元方法

1.引言 热传导-对流问题是大气动力学中的一个重要的方程,这个方程组也称为强迫耗散的非线性系统方程组,其较Navier-Stokes方程多了一个未知函数温度场,且温度与速度和压力之间存在着复杂的非线性关系.从热动力学可知,任何运动都会产生热量即有温度,而且温度与速度和压力之间必定互相转化,因此对该非线性系统的研究更具有实际意义.[1]先对     

三效催化剂作用下的NO+CO催化反应机理

NO与CO在Pt/Rh/Pd及载体组成的三效催化剂上的氧化还原应用是控制汽车尾气对空气污染的一个关键反应，这一反应随着近年来对环境保护的日益重视而成为国内外研究的热点，本文主要综述了NO及CO在Pt,Rh,Pd上的吸附及反应机理的实验及理论研究现状，总结得出：在三效催化剂对NO CO的催化反应中，Pt,Pd对CO的催化氧化起主要作用，而Rh对NO的解离有很好的活化作用。     

DNA Degradation of Genetically Modified Cottonseed Meal During Feed Processing

The effects of dry heating, wet heating, and extrusion on the degradation of DNA in cottonseed meal (CSM) were studied using polymerase chain reaction (PCR) and real-time PCR approach. Both the sad1 DNA, ranging between 128 and 883 bp in size, and the cry1Ab/c gene, ranging between 183 and 652 bp in size, were detectable in all dry-heated CSM and cottonseed. During wet heating, the sad1 gene (≥883 bp) and the cry1Ab/c (≥952 bp) gene were thoroughly degraded at 105 and 120 °C, respectively. Sizes from 128 to 530 bp for the sad1 gene and sizes from 183 to 652 bp for the cry1Ab/c gene were detected during extrusion at temperatures ranging from 75 to 135 °C. Fragments ≤883 bp for the sad1 gene and ≤952 bp for the cry1Ab/c gene were detected in all of the extruded samples with water content varying between 26 and 34 %. The copy number ratio of cry1Ab/c to sad1 in samples of Bt cottonseed meal decreased rapidly when the temperature increased during the heating process. In conclusion, feed processing markedly degrades the larger DNA fragments of sad1 and cry1Ab/c, with high temperature and water content being the main factors for that degradation.     

Printed Circuit Board-Based Electrolyte Regulator for Laminar Microfluidics

The trench on a printed circuit board was reconstructed to fabricate a microfluidic framework that allows low-cost production for small quantities and integration with multifunctional elements. An on-chip electrolyte regulator was thus proposed on this platform to analyze diffusion properties in laminar flow. A numerical model was developed, highlighting the interplay between the electrolyte migration and hydrodynamic properties. Solutions with dissolved sodium chloride were simulated and experimentally tested for the regulation of electrical conductivity under the guidance of the normalized Nernst-Planck equation. The diffusion mechanism and the resulting concentration field were demonstrated in detail. This approach provides a satisfactory manufacturing method and a useful tool for integrated microfluidic systems.     

微米及纳米丝光沸石分子筛上二甲醚羰基化反应的积碳分析

对比研究了在传统微米尺寸和新结构纳米丝光沸石催化剂上二甲醚羰基化合成乙酸甲酯的反应行为.结果表明,通过减小分子筛的尺寸到纳米水平,可以有效提高反应物和产物到达或者脱离反应活性位的效率,从而提高了二甲醚的转化率;更重要的是,抑制了硬积碳的生成,使催化剂保持了更高的稳定性.     

Facile Preparation of α‐Zirconium Phosphate/Polyaniline Hybrid Film for Detecting Potassium Ion in a Wide Linear Range

A novel α‐zirconium phosphate/polyaniline (α‐ZrP/PANI) hybrid film used as K⁺ ion sensor was fabricated on carbon paper by electrochemical method. Mechanisms of film formation and detection of K⁺ ions were also proposed. The exfoliated α‐ZrP was mixed with PANI and deposited on carbon paper. The resultant α‐ZrP/PANI film exhibited a good current response to K⁺ ion with different concentrations. It also showed a wide logarithmic linear response in detecting K⁺ ions in the ranges of 10^?8–10^?4 M and 10^?4–10^?2 M, respectively. The results can be attributed to the synergetic effect of α‐ZrP and PANI.     

可调谐二极管激光吸收光谱法测量气体温度

研究了一种新型的非接触式测温技术——可调谐二极管激光吸收光谱(TDLAS)测温技术。介绍了温度测量及调制吸收光谱技术原理,分析了调制幅度对气体温度测量的影响。优选了氧气吸收谱线对13163.78 cm-1和13164.18 cm-1,在搭建的高温实验系统上,实现了气体温度和浓度的同时测量。通过分析实测波形获得了谱线13164.18 cm-1在823~1323 K温度范围内的碰撞展宽系数和温度指数。实验结果表明,在823~1323 K温度范围内,系统温度测量的线性误差为0.65%,最大波动为±15 K。     

基于$q$-差分Painlev\'e方程的几类$q$-差分方程解的性质

文章讨论了几类$q$-差分Painlev\''e方程的亚纯解性质,获得了方程亚纯解的存在性条件、增长级的估计,以及亚纯解$f$的$q$-差分$\Delta_qf(z):= f(qz)-f(z)$的极点收敛指数的估计等结果,进一步推广了Qi-Yang的结果.