Search results for "COMPOSITION"
showing 10 items of 2675 documents
Pyridylcarbene formation by thermal decomposition of 7-bromo-3-methyl-[1,2,3]triazolo[1,5-a]pyridine under pressure
2007
7-Bromo-3-methyl-[1,2,3]triazolo[1,5-a]pyridine 1 at 1.7 atm and 100ºC decompose to form a pyridylcarbene intermediate by nitrogen expulsion. The carbene stabilization give 2-bromo-6- vinylpyridine 2, 1-(6-bromopyridin-2-yl)ethanol 3, 1-(6-Bromopyridin-2-yl)ethanone 4, 2- bromo-6-[2-(6-bromopyridin-2-yl)-2-methyl-trans-cyclopropyl]pyridine 5, and 2-bromo-6-[2-(6- bromopyridin-2-yl)-2-methyl-cis-cyclopropyl]pyridine 6. Abarca Gonzalez, Belen, Belen.Abarca@uv.es ; Ballesteros Campos, Rafael, Rafael.Ballesteros@uv.es
Effect of the milling conditions on the degree of amorphization of selenium by milling in a planetary ball mill
2007
The effect of the milling parameters (rotation speed of the milling device and duration of milling) on the phase composition of the products of milling of fully crystalline selenium has been investigated. The milling was conducted using a planetary micromill and the phase composition of the milling products was determined by differential thermal analysis. It has been found that ball milling leads to the partial amorphization of the starting crystalline material. The content of amorphous phase in the milling products depends, in a rather complicated way, on the milling parameters. At the milling parameters adopted in the present study, the milling product was never fully amorphous. The compl…
Investigation of the effect of intensive ball milling in a planetary ball mill on the thermal decomposition of cadmium carbonate and basic zinc carbo…
2007
The kinetics of thermal decomposition of cadmium carbonate CdCO3 and basic zinc carbonate ZnCO3?nZn(OH)2 and the effect of intensive milling in a planetary ball mill on its parameters, have been investigated. The values of the reaction heat and of the activation energies of thermal decomposition have been determined for both the compounds. Investigations of the thermal decomposition of the products of ball milling of investigated compounds revealed a slight effect of milling conditions on the reaction temperature and heat consumed during the thermal decomposition of ZnCO3?nZn(OH)2. No effect of ball milling on the thermal decomposition of CdCO3 has been found.
Effect of the capping agents on cobalt nanoparticles
2009
The achievement of high information density and fast recording rate in memory devices crucially depends on the structure of magnetic domains. In this paper cobalt nanoparticles are synthesised using two capping agents (TOA, ODA) and two different preparation routes: thermal decomposition (TD) and Solvated Metal Atom Dispersion (SMAD). The interaction of capping agents with free metal clusters and their influence on Co nanoparticles size, atomic structure and oxidation state is investigated by means of X-ray diffraction and X-ray absorption spectroscopy.
The Post-Process Era in Composition Studies and the Linguistic Turn of the 20th Century
2013
In order to present the post-process era in composition as part of the general phenomenon known as the linguistic turn of the 20th century rather than as only the social turn in composition, in this chapter I point to some epistemological developments in composition studies, developments that underlie and define the process and post-process eras in composition as distinguishable rather than distinct periods in the history of the discipline. I apply the term linguistic turn specifically to the epistemological evolution that has taken place in composition studies and present post-process as a phase of this evolutionary process. Accordingly, I try to pinpoint some crucial changes in the ways w…
New insights into the composition of historical remedies and pharmaceutical formulations: the identification of natural resins and balsams by gas chr…
2020
AbstractThe present paper reports one of the first studies on the identification of natural resins and balsams in modern era drug formulations. Gas chromatography coupled with mass spectrometry (GC-MS) was applied to investigate the composition of ancient remedies and pharmaceutical formulations coming from the Spezieria di Santa Maria della Scala in Rome, founded at the end of the seventeenth century by the Discalced Carmelites. The obtained results highlight the presence of complex mixtures containing resinaceous and lipidic-based compounds. Thanks to the detection of characteristic markers, it was possible to identify several natural resins, such as guaiacum resin, ladano resin and scamm…
Comparison between Different Techniques for Volatiles Analyses in Coriander (Coriandrum sativum L.)
2011
Although many papers have been devoted to the study of Coriander fruits aromatic pattern, many differences show up according not only to the provenience of seeds, but also to the analytical methods chosen. In our work, samples from one Coriander small-seeded biotype has been analysed, verifying the differences between (1) the oil extracted by means of a Soxhlet apparatus (2) the same oil sampled by means of HS-SPME and (3) the HS-SPME on the roughly ground seeds, all analysed by direct injection in the GC-MS. The volatile composition detected by means of HS-SPME on oil resembles tightly that performed on Soxhlet extract. With respect to the direct injection, the HS-SPME shows a higher sensi…
Volatile Constituents of the Seed Coat ofZanthoxylum rhetsa(Roxb.) DC.
2010
Abstract The chemical composition of the volatile oil of Zanthoxylum rhetsa seed coat was analyzed by GC and GC/MS. Thirty-four compounds, accounting for 87.4% of the oil were identifed. The major compounds were terpinen-4-ol (32.1%), α-terpineol (8.2%), sabinene (8.1%), β-phellandrene (7.4%) and 2-undecanone (7.1%).
Comparative Investigation on the Nutrient Composition of Healthy and Injured Spruces of Different Locations
1988
Investigations on the content of cations (Ca2+, K+, Mg2+ and Mn2+) were carried out in spruce trees at two exemplary locations in the Taunus montains (Konigstein) and in the Hunsruck mountains (Hattgenstein) in the course of the vegetation period in 1985 and 1986.
Regulation of Rooting Ability of Solanum tuberosum L. Explants by Gaseous Environment, In Vitro
1997
It has been reported by many investigators that morphogenesis of expiant tissue can be regulated by the composition of the nutrient medium as well as by the gaseous environment (Buddendorf-Joosten and Woltering, 1994). The aim of the present study was to investigate different effects on rooting ability of potato expiants in vitro, caused by limited gas exchange and IBA and BAP treatment.