二维渗流相关长度ξ(p)的幂估计(英文)

相关长度ξ(p)是渗流理论中最重要的一个量。本文对它给出了一个幂估计     

STABILITY NUMBER IN SUBCLASSES OF P5-FREE GRAPHS

Two new hereditary classes of P5-free graphs where the stability number can be found in polynomial time are proposed. They generalize several known results.     

Microbalance Techniques in Design and Control of Synthetic Carbons

Peculiarities of carbonization of two styrene/divinylbenzene precursors (one sulfonated, another aminated and phosphorylated) have been investigated by thermogravimetry and differential thermal analysis. It was shown that phosphorus compounds incorporate into carbon structure and cause delayed carbonization. Porous structure and surface properties of synthetic carbons have been investigated by standard (BET, α_s method, DA) and advanced (AED, PSD, regularization) methods from benzene and water adsorption isotherms. It was shown that phosphorus-containing carbon is less microporous and shows highly hydrophilic surface. This revised version was published online in August 2006 with corrections to the Cover Date.     

On the chemical structure of phosphorus compounds in phosphoric acid-activated carbon

Chemical structure of phosphorus species in polymer-based phosphoric acid-activated carbon SP800 was investigated by X-ray photoelectron spectroscopy. It has been shown that most probable structure for phosphorus species is condensed phosphates bound to carbon lattice via COP bonding.     

循环流化床气固曳力模型

气固曳力是稠密气固两相流动,尤其是垂直流动中的主要作用力,相应的模型也是数值模拟中准确描述气固两相运动的关键.为了解决现有经验或半经验模型的普适性问题,合理描述流动中经常发生的颗粒团聚现象及其对气固曳力的影响,从理论分析入手,运用最小能量的概念,将传统的CFD方法与宏观的系统分析方法相结合,建立了一个新的计及颗粒团聚效应的气固曳力理论模型.与现有模型相比,新模型不仅具有相同的函数变化关系,可合理地描述气固两相相互作用的物理过程,而且避免了以往经验系数不准确导致的各种误差,为稠密气固两相流动的数值描述提供了重要依据.     

Nanostructured carbons for solid phase extraction

Nanostructured carbons have been obtained by the template method using zeolite NaY and silica gels (SG60, Fluka and ZK, POCh) as structure directing agents. Texture and porous structure of carbons were characterized by TEM, XRD and nitrogen adsorption. Surface chemistry was investigated by the potentiometric titration method. It has been shown that all carbons show developed and uniform porous structure with mean size in the micropore range (1.1 nm) for zeolite derived carbon and in the mesopore range (3.4 and 4.8 nm) for silica gel derived carbons. The BET surface area of silica gel derived carbons is in the range 1230-1280 m²/g whereas zeolite derived carbon possesses very high BET surface area, 3000 m²/g. Potentiometric titration showed that carbons obtained by the template method contain significant amount of acid surface groups (carboxylic, lactone/enol and phenolic) with the total amount 1.1-1.5 mmol/g. To study adsorption-desorption properties of nanostructured carbons towards phenol and chlorophenols the solid phase extraction method was used. High recoveries of chlorophenols were obtained (80-93%) at the breakthrough volumes 1700-3000 mL. The recoveries are much higher than that obtained with commercially available carbon ACC (Supelco).