Comparison between Eulerian and Lagrangian semi-analytical models to simulate the pollutant dispersion in the PBL

In this work we display a numerical comparison, under statistical and computational point of view, between semi-analytical Eulerian and Lagrangian dispersion models to simulate the ground-level concentration values of a passive pollutant released from a low height source. The Eulerian approach is based on the solution of the advection–diffusion equation by the Laplace transform technique. The Lagrangian approach is based on solution of the Langevin equation through the Picard’s Iterative Method. Turbulence inputs are calculated according to a parameterization capable of generating continuous values in all stability conditions and in all heights of the Planetary Boundary Layer (PBL). Numerical simulations and comparisons show a good agreement between predicted and observed concentrations values. The comparison reveals the main advantages and disadvantages between the models.     

固体CD光谱研究及其应用于手性席夫碱M(II)配合物

结合课题组近期的相关研究,对固体CD光谱在手性配合物研究中的应用,特别是手性样品固体CD光谱的测试方法进行了概述,通过对四对手性席夫碱M(II)(M=Ni、Cu)配合物的固体和溶液CD光谱进行比较研究,发现配合物的手性构型在固液相中保持一致,但其固液CD光谱之间存在不同程度的差异,可能是由于相应配合物在固体和溶液相中的四面体扭曲或构象的微妙不同所致.     

Thermoanalytical characterization of carbon/carbon hybrid material, Apple Woodceramics

Woodceramics, a carbon/carbon composite of plant-originated carbon reinforced by glassy carbon from phenolic resin, was prepared from apple pomace at carbonizing temperatures of 1073 K (AWC800) and 1473 K (AWC1200), and characterized by thermoanalytical methods and X-ray diffraction (XRD). Simultaneous differential scanning calorimetry (DSC) and thermogravimetric (TG) showed complicated overlapping reactions similar to those of coal. The initial temperature of pyrolysis was obtained by fitting logistic functions to observed TG data. The results suggested that AWC1200 contained more volatile matter than AWC800. In an inert atmosphere, complicated devolatilization takes place. In an oxidizing atmosphere, thermal change occurs roughly in four steps: desorption of physically adsorbed matter; pyrolysis into aliphatic and aromatic fragments; ignition; combustion of char. The oxidation resistance of AWC1200 was superior to AWC800.     

Multivariate resolution of NMR labile signals by means of hard- and soft-modelling methods

One of the difficulties frequently encountered when studying acid–base equilibria with NMR spectroscopy is the labile behaviour of the measured signal, which hinders the application of bilinear multivariate data analysis methods. In this work, a mathematical transformation is proposed for the conversion of NMR labile signals to inert signals, which make possible the application of multivariate data analysis methods, based on bilinear data models. The procedure has been applied to the analysis of NMR data corresponding to the acid–base equilibria of nucleotides dCMP and dGMP. Both hard-modelling (EQUISPEC) and soft-modelling (MCR-ALS) approaches have been applied for the analysis and resolution of transformed bilinear NMR data matrices.     

对固体圆二色光谱测试方法的再认识——兼谈“浓度效应”

对近期发展的固体圆二色(CD)光谱测试方法进行了概述、评价和比较, 着重探讨了“浓度效应”的存在使固体CD光谱失真的原因. 通过对本课题组和其他作者已报道的四种化合物的固体CD谱再测试的反思, 强调了依手性化合物的手性光谱学性质不同, 根据浓度梯度实验选择其合适测试浓度的必要性. 对固有手性的阻转异构化合物(S)-1,1'-联二萘酚(S-BINOL)进行了成膜法固体CD谱浓度梯度测试, 发现所得固体薄膜CD谱中也存在着“浓度效应”     

A competitive (dual) simplex method for the assignment problem

Where there is abundance of mystery and confusion in every direction, the truth seldom remains hidden for long. It's a matter of having plenty of angles to go at it from. Only the utterly simple crimes - the simplex crimes, you may say - have the trick of remaining baffling. - Sir John (from Michael Innes,The Open House (A Sir John Appleby Mystery), Penguin Books, 1974).A dual simplex method for the assignment problem leaves open to choice the activity (i,j) of rowi and columnj that is to be dropped in pivoting so long asx _ij < 0. A choice (i,j) over columnsj having at least 3 basic activities that minimizesx _ij is shown to converge in at most ( ₂ ^n-1 ) pivots, and at most O(n ³) time, and it is argued that on average the number of pivots is at mostn logn. Dedicated with affection to George B. Dantzig on the occasion of his seventieth birthday.     

聚类分析法在食品TE分级中应用研究

用１５种食品的Ｚｎ、Ｃｕ、Ｆｅ、Ｍｇ含量作分级特征，按聚类分析分级，结果以Ｚｎ、Ｃｕ、Ｆｅ、Ｍｇ总量均值最低的蕃茄为Ⅰ级；低的白鸡、鲜牛奶、黄瓜、新会柑、罗岗橙为Ⅱ级；高的精面粉、水豆腐、粉丝、牛肉、鸡蛋、鸭蛋、西洋菜、白芽为Ⅲ级；最高的红豆为Ⅳ级．提示膳食中Ｚｎ、Ｃｕ、Ｆｅ、Ｍｇ含量大于供给量标准时可选Ⅲ、Ⅳ级，小于标准选Ⅰ、Ⅱ级，＝标准选Ⅰ、Ⅲ级食品．据此认为聚类分析法可用于食品分级，对选择食品、制订食谱、营养治疗、食品科研、研制食品配方等均具有实用价值和指导意义。     

非线型缩聚物的重均分子量

本文用数学期望方法研究了非线型共缩聚物的重均分子量,并推导出重均分子量表达式,将3种特例的理论曲线与实验结果相比较,两者基本相符。     

A practical approach to transferring linear gradient elution methods

Attempts to theoretically address the problems involved in transferring linear gradient elution methods have been somewhat ad hoc due to the simplifying assumptions usually made in conventional gradient elution theory. Until now, all equations based on the k* parameter of linear gradient elution theory used as the basis for predicting the separation selectivity have not explicitly included the effect of the dwell volume (VD). Using an exact equation for predicting k*, that is, one which fully accounts in an a priori fashion for VD, we find a set of simple yet exact equations which unequivocally must be satisfied to transfer an optimized linear gradient elution method from one system (column or instrument or both) to another. These relationships absolutely mandate that a change in the instrument dwell volume requires a proportional change in the column volume; in turn, a change in the column volume requires a proportional change in the flow rate and/or gradient time to maintain a constant gradient steepness. Although we are not the first to suggest these guidelines, this work provides a complete theoretical foundation for these exact guidelines for the maintenance of gradient selectivity for the case of transferring a linear gradient elution method between different columns packed with the same particles and/or between different instruments.     

对固体圆二色光谱测试方法的再认识——兼谈“浓度效应”

对近期发展的固体圆二色(CD)光谱测试方法进行了概述、评价和比较, 着重探讨了“浓度效应”的存在使固体CD光谱失真的原因. 通过对本课题组和其他作者已报道的四种化合物的固体CD谱再测试的反思, 强调了依手性化合物的手性光谱学性质不同, 根据浓度梯度实验选择其合适测试浓度的必要性. 对固有手性的阻转异构化合物(S)-1,1'-联二萘酚(S-BINOL)进行了成膜法固体CD谱浓度梯度测试, 发现所得固体薄膜CD谱中也存在着“浓度效应”