476 research outputs found
We Found 29 Habits and Practices Adopted by Effective Fish and Wildlife Management Professionals
Synthesis and Structure of Aminoguanidinium Sulfite Monohydrate
AbstractâThe reaction between sulfur(IV) oxide and an aqueous suspension of aminoguanidinium hydro
carbonate yields (CN4H7)2SO3 â
H2O, an âoniumâ sulfite, which has been characterized by Xray diffraction
and IR spectroscopy and mass spectrometry. The structure of the salt is stabilized by numerous Hbonds, such
as NHâ
â
â
O, OHâ
â
â
O, and NHâ
â
â
N. The incorporation of pyramidal ions into the network of Hbonds is
accompanied by the lowering of their symmetry in comparison with C3v, thus complicating the IR spectra of
the salt in the region where the vibrations of the anion appear
Synthesis, Crystal Structure, Vibrational Spectra, and Thermochemical Transformations of Tris(hydroxymethyl)aminomethane
AbstractâA practically promising compound, tris(hydroxymethyl)aminomethane sulfate ((TRISH)2SO4,
C8H24N2O10S) was synthesized and studied by a set of experimental methods (elemental analysis, IR and
Raman spectroscopy, mass spectrometry, thermogravimetry)
Products of Interaction between Sulfur(IV) Oxide and Aqueous Solutions of Hexamethylendiamine and tertButylamine: The Crystal Structure of Hexamethylenediammonium Sulfate Dihydrate
The possibility of mild SO2 oxidation in sulfur(IV) oxideâalkylamineâwaterâoxygen systems is demonstrated to yield onium sulfates
Cs2Bi(PO4)(WO4)
Dicaesium bisÂmuth(III) phosphate(V) tungstate(VI), Cs2Bi(PO4)(WO4), has been synthesized during complex investigation in a molten pseudo-quaternary Cs2OâBi2O3âP2O5âWO3 system. It is isotypic with K2Bi(PO4)(WO4). The three-dimensional framework is built up from [Bi(PO4)(WO4)] nets, which are organized by adhesion of [BiPO4] layers and [WO4] tetraÂhedra above and below of those layers. The interÂstitial space is occupied by Cs atoms. Bi, W and P atoms lie on crystallographic twofold axes
Synthesis, Crystal Structure, and Spectral Characteristics of N-(tert-Butyl) aminomethanesulfonic Acid
A new method of the synthesis of N-(tert-butyl)aminomethanesulfonic acid in the system SO2â(CH3)3CNH2âCH2OâH2O was developed. The target compound [(CH3)3ĐĄ]NHCH2SO3H was characterized by means of X-ray diffraction analysis, IR spectroscopy, and mass spectrometry
Interaction Products in the System Sulfur Dioxideâ2,2âČ-BipyridineâWater. Van der Waals Clathrates
Crystallization of 2,2âČ-bipyridine from aqueous solution containing sulfur(IV) oxide afforded clathrates with the composition (bipy)k·(SO2)m·(H2O)n. X-Ray amorphous guest SO2 molecules occupy voids in the crystal lattice of 2,2âČ-bipyridine without distortion of its structure. The isolated compounds were
characterized by elemental analyses, X-ray diffraction data, and IR, NMR, and mass spectra
Characterization of commercial synthetic resins by pyrolysis-gas chromatography/mass spectrometry : application to modern art and conservation
To characterize a set of synthetic resins, a methodology by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) has been developed. The studied reference materials were commercial versions of a wide range of synthetic resins. For each polymer, the pyrolytic and chromatographic conditions were optimized to adequately resolve the fragment mixture in a short time. The proposed
analytical method does not require previous treatment of the sample, and due to its high sensitivity, only a small sample quantity in the microgram range can be used. The pyrolysis temperature was found to have little effect on the obtained pyrograms. The summarized data set for the individual polymer materials, especially the characteristic fragments with a structure close to the monomeric unit, was useful to identify commercial synthetic resins. These materials were used in the art and
conservation field, as binding media, paint additives, painting varnishes, coatings, or consolidants. Two case studies are introduced where direct Py-GC/MS and thermally assisted hydrolysis and methylation GC/MS were applied on art objects: first, a modern gluing material of a medieval reverse glass painting, and the second example, the binding medium of a painting by Georg Baselitz (âSentaâ, 1992/1993) from the Sammlung Moderne Kunst at the Pinakothek der Moderne, MunichVersiĂł editoria
Onium Salts of Sulfur-Containing Oxyanions Resulting from Reaction of Sulfur(IV) Oxide with Aqueous Solutions of 1,2-Diamines and Morpholine
Reaction products have been isolated from SO2âLâH2OâĐ2 systems (L = ethylenediamine,
N,N,N',N'-tetramethylethylenediamine, piperazine, and morpholine) as onium salts
[H3NCH2CH2NH3]SO4, [(CH3)2NHCH2CH2NH(CH3)2]SO4, [(CH3)2NHCH2CH2NH(CH3)2]S2O6 â
H2O, [C4H8N2H4]SO3 â
H2O, [C4H8N2H4]S2O6, [C4H8N2H4]SO4 â
H2O, [O(C2H4)2NH2]2SO4 â
H2O. The
prepared compounds have been characterized by X-ray diffraction analysis, X-ray powder diffraction, IR and
mass spectroscopy
Lifetime Measurement of the 6s Level of Rubidium
We present a lifetime measurements of the 6s level of rubidium. We use a
time-correlated single-photon counting technique on two different samples of
rubidium atoms. A vapor cell with variable rubidium density and a sample of
atoms confined and cooled in a magneto-optical trap. The 5P_{1/2} level serves
as the resonant intermediate step for the two step excitation to the 6s level.
We detect the decay of the 6s level through the cascade fluorescence of the
5P_{3/2} level at 780 nm. The two samples have different systematic effects,
but we obtain consistent results that averaged give a lifetime of 45.57 +- 0.17
ns.Comment: 10 pages, 9 figure
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