Search results for "Solid"

1992

The synthesis and the results of the structural study of two copolysiloxanes with laterally fixed trinitrofluorenone (TNF) units is reported. The two copolysiloxanes having 2,4 (1a) and 5,3 (1b) dimethylsiloxane comonomer units per TNF side group differ significantly in their phase behaviour as evident from optical microscopy, differential scanning calorimetry and X-ray scattering: 1b shows a nematic mesophase whereas 1a is an amorphous material. The different phase behaviour is discussed in terms of microphase separation between the siloxane backbone and TNF side groups.

From Single Molecules to Nanoscopically Structured Functional Materials

2006

AbstractThe synthesis of MS2 (M = Mo, W) onion-like nanoparticles by means of a high temperature MOCVD process starting from W(CO)6 and elemental sulfur is reported. The reaction can also be carried out in two steps where the intermediate amorphous WS2 nanoparticles formed through the high temperature reaction of tungsten and sulfur in the initial phase of the reaction are isolated and converted in a separate annealing step to onion-type WS2 nanoparticles. Based on a study of the temperature dependence of the reaction a set of conditions could be derived where onion-like structures were formed in a one-step reaction. Onion-like structures obtained in the single-step process were filled, whe…

Rapid fluorimetric assay for primary amine groups in water samples

2003

Bond Elut C(18) solid-phase extraction cartridges were used for pre-concentration followed by derivatization with o-phthaldialdehyde-N-acetylcysteine (OPA-NAC) of primary amines in water. Optimal conditions were: conditioning the cartridges with borate buffer pH 10.4, retention of the primary amines, addition of the OPA-NAC(3.7 mmol L(-1)) 1:1 molar ratio and borate buffer pH 8, elution of the isoindol with MeOH-borate buffer (9:1) pH 10.2 and fluorescence measurement. The equations of the calibration graphs for methylamine, ethylamine, propylamine, butylamine, pentylamine, and beta-phenylethylamine at lambda(excitation)=330 nm and lambda(emission)=440 nm, in the optimal conditions are pres…

Solid-Phase Synthesis of Oligo(p-benzamide) Foldamers

2006

[reaction: see text] A coupling protocol has been developed which allows the synthesis of oligo(p-benzamide)s on solid support. Aromatic carboxylic acids are activated in situ with thionyl chloride and used to acylate secondary aromatic amines. N-p-Methoxy benzyl (PMB) as well as N-hexyl protected monomers were investigated. Heterosequences of both monomers were synthesized. Such nanoscale objects are important building blocks for supramolecular chemistry.

Topochemical reactions of monomers with conjugated triple bonds. III. Solid-state reactivity of derivatives of diphenyldiacetylene

1971

ChemInform Abstract: COMPLEXES OF ORGANOMETALLIC COMPOUNDS PART 42, SPECTROSCOPIC STUDIES OF N,N′-ETHYLENEBIS(ACETYLACETONEIMINE) AND N,N′-ETHYLENEBI…

1975

Abstract The nature of the 1 1 adducts formed from the ligands N,N′-ethylenebis(acetylacetonemine) and N,N′-ethylenebis(salicylideneimine) with Ph2PbCl2 and PhTlCl2 was investigated in the solid state and in methanol solution by IR, electronic and PMR spectroscopy, and by osmometry and conductivity. The adducts exist only in the solid state and dissociate fully into the parent compounds in solution. Polymeric structures are proposed for the solids, in which bis-monodentate ligands bridge the organometallic moieties.

On lead-scandium tantalate solid solutions with high electrocaloric effect

1992

Abstract The PbSc0,5Ta0,5O3 solutions are found to be a useful material for active elements of microcryogenic devices based on electrocaloric effect. A temperature difference of ΔT = 1. 0-1.8 K at field intensities 20–30 kV/cm in the interval of 210–310 K can be achieved by simultaneous or separate introducing of Sb and Co ions in B-sites of the lattice. The most important contribution to the electrocaloric effect is due to field-induced Fn3m → R3m phase transition in the case of high ordering of B-ions in the perovskite structure ABO3.

The structure of ammonium pyrazolates in the solid state

2006

The crystals obtained by mixing equimolar amounts of diethyl 1H-pyrazole-3,5-dicarboxylate and the primary amines phenethylamine and homoveratrylamine are ammonium pyrazolate salts as determined by 13C and 15N CPMAS NMR. Copyright © 2006 John Wiley & Sons, Ltd.

Transferability of ASTM/NIST alanine–polyethylene recipe at ISS

2000

Abstract Alanine–polyethylene solid state dosimeters were prepared at Istituto Superiore di Sanita (ISS) following the recipe proposed by National Institute of Standards and Technology (NIST) with the goal of testing its transferability. Dosimeters were prepared using 95% alanine and 5% polyethylene, by weight. They are rugged and of increased sensitivity, repeatability and reproducibility as respect to the ISS alanine-paraffin pellets. Reproducibility of about 1% was obtained at 10 Gy and at 3 Gy if one single pellet or a stack of five dosimeters were used, respectively.

New developments in immunochemical water analysis down to 30 mul sample volume.

1999

Abstract The determination of trace levels of pesticides like atrazine in water samples of small, restricted volumes is one of the future demands of environmental analysis. In a brief review existing chromatographic and immunochemical methods for atrazine are critically discussed. Then a simple rapid enzyme-linked immunosorbent assay (ELISA) using the tip of an inoculation needle as a solid surface is presented. The sample volume could be reduced to 30 μl. The assay had a centre of the test IC50 of 0.12 μg l−1 and permitted the characterisation of atrazine at levels of 0.022–2.90 μg l−1. A first outlook for automatisation is given. The new method was compared with an ELISA using 96 well mic…