Separation of antipyretic analgesics by open tubular capillary electrochromatography with homopolymer coatings

This study developed an open‐tubular capillary electrochromatography protocol for the analysis of antipyretic analgesic drugs, which used a multifunctional homopolymer as coating. A controlled/living radical polymerization strategy was adopted to obtain poly(N‐acryloxysuccinimide) with a tunable chain‐length. The homopolymer coating enhanced the separation performance by contributing to the hydrophobic and hydrogen‐bonding interactions between the analytes and the homopolymer. The effect of polymer chain‐length and buffer pH and concentration on the separation efficiency was evaluated. In this approach, baseline separation of the three test drugs was achieved within 15 min. The repeatability of the prepared homopolymer coating was investigated, with the relative standard deviations < 2.88% observed in intra‐ and interday runs. Good linearity in the 5–800 µM range (R² ≥ 0.998) demonstrates that accurate quantitative analysis of real samples was achieved. Moreover, the proposed assay was used to quantify the three drugs (aminopyrine, 4‐aminoantipyrine, and phenacetin) in urine samples, achieving recovery rates between 92.1 and 108.7%. This promising methodology may be used for the analysis of drugs in real bio‐samples and for the development of unique homopolymer coatings for open‐tubular capillary electrochromatography systems.     

铅基堆超临界CO2复合循环发电系统热力学分析

本文对比了再压缩超临界CO2 (S-CO2)循环、蒸汽朗肯循环、He布雷顿循环分别应用于铅基堆的最优热学性能,明确了S-CO2循环与铅基堆结合较传统循环的热力学优势。为进一步提高再压缩S-CO2循环的效率,以跨临界CO2 (T-CO2)循环为底循环构建了再压缩S-CO2/T-CO2复合循环,探讨了不同顶循环透平入口温度、压力和压缩机入口温度条件下系统性能的变化规律,对比了S-CO2/T-CO2复合循环和S-CO2循环的热学性能。结果表明:铅基堆再压缩S-CO2循环发电系统较传统循环形式具有更高的热效率;构建的S-CO2/T-CO2复合循环能够有效提高S-CO2循环的效率,在所研究参数范围内,S-CO2/T-CO2复合循环的热效率和效率比S-CO2循环分别最大可提高约4.8%和8.3%;再压缩S-CO2循环和S-CO2/T-CO2复合循环热学性能随顶循环关键参数变化规律具有一致性。     

Experimental and kinetic modeling study of the oxidation of cyclopentane and methylcyclopentane at atmospheric pressure

Cyclopentane and methylcyclopentane oxidation was investigated in a jet-stirred reactor at atmospheric pressure, over temperatures ranging from 900 to 1250 K, for fuel-lean, stoichiometric, and fuel-rich mixtures at a constant residence time of 70 ms. The initial mole fraction of both fuels was kept constant at 1000 ppm. The reactants were highly diluted by a flow of nitrogen to ensure thermal homogeneity. Samples of the reacting mixture were analyzed online and off-line by Fourier transform infrared spectroscopy and gas chromatography. A detailed kinetic mechanism consisting of 590 species involved in 3469 reactions was developed, and simulation results were compared to these new experimental data and previously reported ignition delays. Reaction pathways analysis as well as sensitivity analyses were performed to get insights into the differences observed during the oxidation process of cyclopentane and methylcyclopentane.     

基于VHTRC的棱柱式高温气冷堆核设计程序验证北大核心CSCD

高温气冷堆是国际公认的固有安全性高的反应堆堆型。针对高温气冷堆包覆颗粒燃料引入的燃料组件的双重非均匀性以及棱柱式堆芯布置的非均匀性和强空间耦合效应,提出基于蒙特卡罗均匀化-确定论输运方法的RMC-SaraGR程序系统作为棱柱式高温气冷堆的核设计程序。基于日本棱柱式高温气冷堆临界实验装置VHTRC基准题,针对此套核设计程序系统开展了均匀化模型研究和初步验证。研究结果表明,基于蒙特卡罗均匀化方法,采用全堆模型、合适的能群结构和分区方式产生组件群常数,并经过超级等效均匀化方法进行等效均匀化修正,可以保证堆芯多群均匀计算具有较高的计算精度。     

多釜串联模型停留时间分布方差的推导

简要分析了理想反应器的特点,并指出现实反应器与理想反应器的区别,介绍了多釜串联模型描述实际反应器的思想.针对多釜串联模型的停留时间分布的计算函数进行逐步的推导,以阶跃法对模型进行分析,采用数学归纳法和分部积分法等方法推导出了多釜串联模型无因次停留时间分布函数表达式;根据停留时间分布密度函数定义,推导出了无因次停留时间分布密度函数的表达式;根据概率中方差的定义,推导出了无因次方差的表达式.     

用概率断裂力学方法预测管状接头的疲劳寿命

本文研究了Ｔ型管状接头在面内和面外弯曲循环载荷作用下的疲劳强度问题，通过将材料常数和初始裂纹尺寸作为随机变量，采用ＭｏｎＣａｒｌｏ模拟方法对疲劳寿命进行了统计分析．同时，对计算结果进行了线性回归，并与实验结果作了比较。     

TEXONO反应堆中微子能谱的计算

在低能反应堆中微子物理实验中,无论是研究中微子振荡、中微子反应还是测量中微子反常磁矩,都必须准确地知道反应堆中微子的通量和能谱.本文详细讨论了反应堆中微子能谱的计算方法,依据TEXONO实验所用的NP2反应堆的实际情况及探测器的安排,计算并得到中微子的通量和能谱.     

次临界能源堆物理设计进展

聚变-裂变混合能源堆包括聚变中子源和次临界能源堆,主要目标是生产电能。回顾了国内外混合堆的发展历史,给出混合能源堆设计的边界条件和约束条件,说明次临界能源堆以铀锆合金为燃料、水为冷却剂的设计思想。利用输运燃耗耦合程序 MCORGS 计算了混合能源的燃耗,给出了中子有效增殖因数、能量放大倍数和氚增殖比等物理量随时间的变化。通过分析能谱和重要核素随燃耗时间的变化,说明混合能源堆与核燃料增殖、核废料嬗变混合堆的不同特点。论述了混合堆的热工设计并进行了安全分析。对于燃耗数值模拟程序,通过多家对算,保证其计算结果的可信性。针对次临界能源堆的特点,利用贫铀球壳建立了贫铀聚乙烯装置和贫铀LiH装置,并且专门设计加工了天然铀装置,开展铀裂变率、造钚率、产氚率等中子学积分实验,验证了数值模拟的可靠性。     

Formation of Si-nanoparticles in a microwave reactor: Comparison between experiments and modelling

The formation and growth of silicon-nanoparticles from silane in a microwave reactor was investigated. Experiments were performed for the following conditions: precursor concentration 380–2530 ppm, pressures of 20–30 mbar, microwave powers 120–300 W. The formed particles were examined in-situ with a particle mass spectrometer. Additionally, particles were collected on grids and analyzed by transmission electron microscopy, X-ray diffraction, and by determining the specific surface area by BET. The particle size was found to be in the range of 5–8 nm in diameter. A simple model was used to simulate the particle formation processes taking place inside the reactor. The microwave energy coupled into the reactor flow was treated as a spatially distributed energy source resulting in a local temperature increase. The particles were assumed to have a monodisperse size distribution. To allow an approximation of their shape they were characterized by their volume and surface area. The model takes nucleation, convection, coagulation, and coalescence into account. The fluid flow inside the microwave reactor was simulated with the commercial CFD-code Fluent.     

应用DQE增量迭代法分析斜直井内管柱的非线性屈曲

基于斜直井内管柱屈曲的平衡微分方程,构建DQE (Differential Quadrature Element)增量迭代法,对斜直井内管柱的非线性屈曲进行计算.通过与有限元的计算结果对比,验证方法的正确性.DQE法方法简单、易于实施,计算量少、精度较高,所得到的螺旋屈曲计算结果与实验结果吻合,最大井壁约束力随上端载荷的增加而增大.对于工程中比较长的受压段管柱,其屈曲是一个局部非线性稳定性问题,屈曲首先从下端开始发生,随着上端载荷的增加,逐渐向上扩展;上端边界条件对下端局部屈曲无明显影响.