A rapid method for the estimation of calcium and magnesium carbonates in limestones, dolomite and other calcareous materials

Summary Calcium and magnesium carbonates are determined in minerals by dissolving the sample in ammonium chloride solution and subsequent chelatometric titration. Iron and aluminium are dissolved, it any, in traces only.

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Zusammenfassung Calcium- und Magnesiumcarbonat werden in Mineralen bestimmt, indem man die Probe in Ammoniumchloridlösung auflöst und anschlie\end chelatometrisch titriert. Eisen und Aluminium werden nur in vernachlÄssigbaren Mengen gelöst.

     

Representation of finite action large games

A large game can be formalized as a probability distribution on the set of players' characteristics or as a function from a measure space of players to the set of players' characteristics. Given a game as a probability distribution on the set of players' characteristics, a representation of that game is a function from a set of players to the set of players' characteristics which induces the same distribution. It is shown that if the playoffs are continuous and there are only finite number of actions, then the set of Nash equilibria of any representation of a game induces essentially all the Cournot-Nash equilibrium distributions of the given game.     

Kinetics and mechanism of the oxidation of ethylene glycol, 2,3-butanediol and pinacol by hexachloroiridate(IV)

Summary The kinetics of oxidation of ethylene glycol, 2,3-butanediol and pinacol have been studied spectrophotometrically under different experimental conditions. The reactions seem to occur through the formation of an intermediate complex between each diol and iridium(IV). The complexes decompose through intermediate free radicals to form formaldehyde, acetaldehyde and acetone, respectively. Thermodynamic parameters have been calculated.     

Star and Hyperbranched Polyisobutylenes via Terminally Reactive Polyisobutylene-Polystyrene Block Copolymers

Unique, highly branched polyisobutylenes (PIB) were prepared via quasiliving carbocationic copolymerization of isobutylene and styrene (St) monomers. The junction points were formed by Friedel-Crafts self alkylation of PSt segments by the carbocationic chain ends. First, linear PIB was prepared with reactive chain ends. This was reacted with St monomer to form PIB-b-PSt AB, and PSt-b-PIB-b-PSt ABA type triblock copolymers with reactive carbocationic chain ends. The terminal carbonations react with the phenyl group of the polystyrene end-segments of the block copolymers leading to chain coupling, and thus PIB star polymers in the case of AB and hyperbranched PIB from ABA block copolymers. The resulting branched polymers were characterized and the branch formation was confirmed by gel permeation chromatography (GPC) and proton nuclear magnetic resonance spectroscopy (¹H NMR).     

Design,synthesis, anticancer activity,and in silico studies of novel imidazo[1,2-a]pyridine based 1H-1,2,3-triazole derivatives

A novel series of imidazo[1,2-a]pyridine based 1H-1,2,3-triazole derivatives were designed, synthesized, and evaluated for their anticancer activity against two different human cancer cell lines. Most of the synthesized compounds displayed anticancer activity with IC₅₀ values from 2.35 to 120.46 μM. Furthermore, compounds 9b , 9c, 9d, 9f , and 9j showed potent inhibitory activity against cancer cell lines, with IC₅₀ values close to that of standard drug. It is important to note that compound 9d was more potent than the standard drug cisplatin with IC₅₀ values of 10.89 and 2.35 μM against Hela cell line and MCF-7 cell line, respectively.     

Crystal structure, spectroscopic and magnetic properties, and antimicrobial activities of cobalt(II) 2-methylthionicotinate complexes with N-heterocyclic ligands

Synthesis and characterization of 10 new 2-methylthionicotinate (2-MeSnic) Co(II) complexes, namely, [Co(2-MeSnic)₂L₂(H₂O)₂] · nH₂O (L is N,N-diethylnicotinamide—Et₂nia, ethylnicotinate—Etnic, nicotinamide—nia, isonicotinamide—isonia, N-methylnicotinamide—N-Menia, furo[3,2-c]pyridine—fpy, 2,3-dimethylfuro[3,2-c]pyridine—Me₂fpy or benzo[4,5]furo[3,2-c]pyridine—Bfp; n is 0, 1 or 2) as well as [Co(2-MeSnic)₂L₂] (L is ronicol—ron or 2-methylfuro[3,2-c]pyridine—Mefpy), are reported. The characterizations were based on physico-chemical and spectroscopic methods. The crystal structure of one of the complexes has been determined. In the molecular complex [Co(2-MeSnic)₂(Me₂fpy)₂(H₂O)₂], the Co(II) central atom, located at a symmetry centre, is octahedrally coordinated by an oxygen atom of the unidentate 2-MeSnic carboxyl group, the nitrogen atom of the pyridine ring of Me₂fpy, a water molecule and the corresponding centrosymmetrically located atoms. Also, biological activity of the complexes against various strains of bacteria and filamentous fungi has been investigated. It is concluded that by complexation of these nicotinate derivatives their biological activities are elevated. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

钝化处理1Cr18Ni9Ti不锈钢在H2O2 水溶液中的摩擦学性能初探

为研究1Cr18Ni9Ti不锈钢钝化膜在H2O2水溶液中的摩擦学性能,对1Cr18Ni9Ti不锈钢表面进行了酸洗钝化处理,利用CS300电化学测试系统和XPS对不锈钢表面钝化膜的电化学行为、元素组成和化学状态进行了分析;用SST销-盘式摩擦磨损试验机研究了1Cr18Ni9Ti不锈钢盘与GCr15钢球摩擦副在不同浓度H2O2水溶液中配副时的摩擦学性能;用TR240形貌轮廓仪和扫描电子显微镜(SEM)观察分析了盘试样磨损处的轮廓形貌、磨痕面积和微区结构.结果表明,1Cr18Ni9Ti不锈钢经钝化工艺处理后,耐腐蚀性能显著提高,且表面形成一层富氧、富铬、贫铁的钝化膜,其主要成分是Cr2O3;钝化后的1Cr18Ni9Ti不锈钢在过氧化氢溶液中的摩擦系数较钝化前均出现不同程度的降低,耐磨性提高;钝化或未钝化的1Cr18Ni9Ti不锈钢在过氧化氢溶液中的磨损机理均表现为黏着磨损、磨粒磨损和腐蚀磨损,但在90%H2O2水溶液中,盘磨损表面的黏着作用明显减轻.