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991.
992.
On the occasion of the celebration of Prof. Rosa Caballol's 65's birthday, a symposium was organized by the Quantum Chemistry Group of the Universitat Rovira i Virgili (Tarragona, Spain) under the title “Theoretical Chemistry in Spain told by women.” The symposium gave a representative illustration of the research in theoretical chemistry in Spain, which is not only very diverse, but also in many areas at the forefront of the field. In this article, we summarize the contributions made by Rosa Caballol and coworkers. Emphasis lies on the developments of wave function based methods to accurately describe electron correlation effects in systems with unpaired electrons. Besides discussing some illustrative applications, we will also explore the limits of the existing methods and outline the perspectives of how one can possibly overcome them. © 2014 Wiley Periodicals, Inc. 相似文献
993.
通过简单高效的醛酮缩合反应,合成了碱性配体2,6-二(4-吡啶基亚甲基)环己酮(BPCH),采用3种芳香羧酸配体:对苯二甲酸(H2TP)、间苯二甲酸(H2IP)和均苯三甲酸(H3TMA),以混合配体策略制备了7例金属有机骨架(MOFs)。用单晶X射线衍射、红外光谱、粉末X射线衍射和热重分析对其进行表征并分析其拓扑结构。MOFs1、2、3均呈现为多样的三维结构,MOFs4~7表现为同构的二维结构。荧光测试结果显示该类化合物对Fe3+有较好的荧光猝灭效应,同时对于染料具有一定的吸附能力。 相似文献
994.
基于半刚性的配体3'',5''-di (1H-1,2,4-triazol-1-yl)-(1,1''-biphenyl)-3,5-dicarboxylic acid (H2DTBDA)和硝酸钴制备了一个柔性超微孔的金属有机骨架{[Co (DTBDA)]·4H2O}n(FJI-H35),并对该材料的结构进行了系统的表征。FJI-H35活化以后可以发生自适应的结构转变,使得孔径从0.43 nm收缩到0.37 nm。气体吸附测试表明FJI-H35可以从氮气和甲烷中选择性捕获二氧化碳,具有很高的吸附选择性和相对低的吸附焓。突破实验进一步证实FJI-H35可以从二氧化碳/氮气(15∶85,V/V)和二氧化碳/甲烷(50∶50,V/V)混合气中高效选择性捕获二氧化碳。 相似文献
995.
丙烯、丙烷作为分子尺寸相近的共沸物,其分离一直是化工领域研究热点。金属有机骨架(MOFs)材料因其高度可调的孔道结构,在丙烯/丙烷分离应用上已展现出诱人潜能。本文基于Core MOF 2019数据库,采用巨正则蒙特卡洛基高通量计算筛选技术,获得了分离性优异的MOFs结构,发现其拥有适中的丙烯吸附量和较弱的丙烷吸附能力,且骨架孔径为3.70~4.10?、孔隙率中等(0.35~0.44),并揭示了孔道中心吸附位的选择性与丙烯/丙烷分离系数间关系。本研究阐明了高丙烯/丙烷分离性的骨架材料的结构和性能特征,为设计MOFs实现丙烯/丙烷的高效分离提供理论指导和数据支撑。 相似文献
996.
The adsorption and dissociation of NH(3) on the clean and hydroxylated TiO(2) rutile (110) surfaces have been investigated by the first-principles calculations. The monodentate adsorbates such as H(3)N-Ti(a), H(2)N-Ti(a), N-Ti(a), H(2)N-O(a), HN-O(a), N-O(a) and H-O(a), as well as the bidentate adsorbate, Ti-N-Ti(a) can be formed on the clean surface. It is found that the hydroxyl group enhances the adsorption of certain adsorbates on the five-fold-coordinated Ti atoms (5c-Ti), namely H(2)N-Ti(a), HN-Ti(a), N-Ti(a) and Ti-N-Ti(a). In addition, the adsorption energy increases as the number of hydroxyl groups increases. On the contrary, the opposite effect is found for those on the two-fold-coordinated O atoms (2c-O). The enhanced adsorption of NH(x) (x = 1-2) on the 5c-Ti is due to the large electronegativity of the OH group, increasing the acidity of the Ti center. This also contributes to diminish the adsorption of NH(x) (x = 1-2) on the two-fold-coordinated O atoms (2c-O) decreasing its basicity. According to potential energy profile, the NH(3) dissociation on the TiO(2) surface is endothermic and the hydroxyl group is found to lower the energetics of H(2)N-Ti(a)+H-O(a) and HN-Ti(a)+2{H-O(a)}, but slightly raise the energetic of Ti-N-Ti(a)+3{H-O(a)} compare to those on the clean surface. However, the dissociation of NH(3) is found to occur on the hydroxylated surface with an overall endothermic by 31.8 kcal/mol and requires a barrier of 37.5 kcal/mol. A comparison of NH(3) on anatase surface has been discussed. The detailed electronic analysis is also carried out to gain insights into the interaction nature between adsorbate and surface. 相似文献
997.
998.
999.
Perez AA Sánchez CC Patino JM Rubiolo AC Santiago LG 《Colloids and surfaces. B, Biointerfaces》2011,85(2):50-315
Milk whey proteins (MWP) and pectins (Ps) are biopolymer ingredients commonly used in the manufacture of colloidal food products. Therefore, knowledge of the interfacial characteristics of these biopolymers and their mixtures is very important for the design of food dispersion formulations (foams and/or emulsions). In this paper, we examine the adsorption and surface dilatational behaviour of MWP/Ps systems under conditions in which biopolymers can saturate the air-water interface on their own. Experiments were performed at constant temperature (20 °C), pH 7 and ionic strength 0.05 M. Two MWP samples, β-lactoglobulin (β-LG) and whey protein concentrate (WPC), and two Ps samples, low-methoxyl pectin (LMP) and high-methoxyl pectin (HMP) were evaluated. The contribution of biopolymers (MWP and Ps) to the interfacial properties of mixed systems was evaluated on the basis of their individual surface molecular characteristics. Biopolymer bulk concentration capable of saturating the air-water interface was estimated from surface pressure isotherms. Under conditions of interfacial saturation, dynamic adsorption behaviour (surface pressure and dilatational rheological characteristics) of MWP/Ps systems was discussed from a kinetic point of view, in terms of molecular diffusion, penetration and configurational rearrangement at the air-water interface. The main adsorption mechanism in MWP/LMP mixtures might be the MWP interfacial segregation due to the thermodynamic incompatibility between MWP and LMP (synergistic mechanism); while the interfacial adsorption in MWP/HMP mixtures could be characterized by a competitive mechanism between MWP and HMP at the air-water interface (antagonistic mechanism). The magnitude of these phenomena could be closely related to differences in molecular composition and/or aggregation state of MWP (β-LG and WPC). 相似文献
1000.
Qinghui Mao Linping Zhang Dehui Huang Dan Wang Yang Huang Hong Xu Huantian Cao Zhiping Mao 《Surface and interface analysis : SIA》2011,43(5):903-912
Preparation and characterization of lamellar magnesium hydroxide (Mg(OH)2) thin films on cotton fabrics are reported in this paper. Mercerized cotton fabrics were treated with citric acid, so carboxyl groups were introduced to the surface of the fabrics. Mg(OH)2 seeds were first adsorbed on the citric acid‐treated cotton fabrics and then Mg(OH)2 thin films grew on the fabric through secondary growth method. Kinetics and isotherm studies found that the adsorption of Mg(OH)2 seeds on citric acid‐treated cotton fabrics followed pseudo second‐order kinetic model and Langmuir isotherm. This indicated that Mg(OH)2 seeds adsorption was monolayer chemical adsorption driven by electric attraction between positively charged Mg(OH)2 seeds and ? COO? ions on the cotton fiber surface. The X‐ray diffraction (XRD) and SEM characterizations of the Mg(OH)2 thin films covered cotton fabrics found that standing flaky Mg(OH)2 crystals formed a shell of porous but continuous network on cotton fabric surface. Owing to the Mg(OH)2 thin film covering, the fabric had fireproof property, lower thermal conductivity and higher optical absorbance in the UV, Vis and IR regions. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献