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981.
R. S. B. Reddi V. S. A. Kumar Satuluri U. S. Rai R. N. Rai 《Journal of Thermal Analysis and Calorimetry》2012,107(1):377-385
Solid–liquid phase equilibrium data of three binary organic systems, namely, 3-hydroxybenzaldehyde (HB)—4-bromo-2-nitroanilne
(BNA), benzoin (BN)—resorcinol (RC) and urea (U)—1,3-dinitrobenzene (DNB), were studied by the thaw–melt method. While the
former two systems show the formation of simple eutectic, the third system shows the formation of a monotectic and a eutectic
with a large immiscibility region where two immiscible liquid phases are in equilibrium with a liquid of single phase. Growth
kinetics of the pure components, the monotectic and the eutectics, studied by measuring the rate of movement (v) of solid–liquid interface in a thin U-tube at different undercoolings (ΔT) suggests the applicability of the Hillig–Turnbull’s equation: v = u (ΔT)
n
, where v and n are the constants depending on the nature of the materials involved. The thermal properties of materials such as heat of
mixing, entropy of fusion, roughness parameter, interfacial energy, and excess thermodynamic functions were computed from
the enthalpy of fusion values, determined by differential scanning calorimeter (Mettler DSC-4000) system. The role of solid–liquid
interfacial energy on morphologic change of monotectic growth has also been discussed. The microstructures of monotectic and
eutectics were taken which showed lamellar and federal features. 相似文献
982.
U. N. Tripathi Mohd. Safi Ahmad 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2307-2313
Triphenylantimony (V) (O-alkyl,O-cycloalkyl and O-aryltrithiophosphates) of the type Ph 3 Sb[S 2 (S)P(OR)] (R = Me, Et, Pr n , Pr i , Bu n , Bu s , Bu i , Am i , Ph and C.h. = cyclohexyl) have been synthesized for the first time by the reaction of triphenylantimony (V) dibromide with potassium trithiophosphates in 1:1 molar ratio in methanol. These new compounds have been characterized by elemental analysis, molecular weight determinations, and spectroscopic (IR,13C and 31P NMR) studies. On the basis of these data trigonal bipyramidal geometry has been proposed for these compounds. 相似文献
983.
Redox initiated free‐radical polymerization of methyl methacrylate (MMA) with allyl alcohol 1,2‐butoxylate‐block‐etoxylate (AABE) was carried out to yield AABE‐b‐PMMA copolymers at elevated temperatures. The composition of the copolymers depending on the polymerization temperature was qualitatively estimated by the dielectric measurements. It has been seen that AABE segment quantity decreased and PMMA segment quantity increased with increasing the polymerization temperature. The dielectric constant and the dissipation factor of the copolymers were investigated as a function of frequency and temperature. The dielectric constant and the dissipation factor were found to be strongly affected by the polymerization temperature. The highest dielectric constant in all studied temperatures and frequencies was obtained in the case of the copolymer which was prepared at 313 K. The dipolar C‐O and OH groups of the AABE segment have the primary effect on the dielectric constant. The copolymer which was prepared at 323 K, showed the highest dissipation factor near the relaxation temperature of PMMA. 相似文献
984.
C.-W. Cho J. Ranke J. Arning J. Thöming U. Preiss C. Jungnickel 《SAR and QSAR in environmental research》2013,24(10):863-882
985.
W.W. Schoeller R. Schneider U. Tubbesing 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):781-784
Mono-and bis-donor-acceptor formation (donor=AH3, Y = N, P, As, Sb, Bi and AH2, O, S, Se, Te) is discussed on the basis of quantum chemical (ab initio) calculations for π-bonded low-coordinated phosphorus cations, evaluating new types of bis-donor adducts. 相似文献
986.
On the Hydrates M(HSeO3)2 · 4H2O (M = Mg, Co, Ni, Zn) – Crystal Structures, IR, Raman, and Thermoanalytical Investigations From aqueous solutions of M(HSeO3)2 single crystals of Mg(HSeO3)2 · 4H2O and of the hitherto unknown compounds Co(HSeO3)2 · 4H2O, Ni(HSeO3)2 · 4H2O and Zn(HSeO3)2 · 4H2O could be obtained. The crystal structures, X-ray powder, IR, Raman and thermoanalytical (DTA, TG, Raman heating) data are presented and discussed. The crystal data of the isotypic compounds are: monoclinic, space group C2/c, Z = 4, Mg: a = 1 464.6(2), b = 755.3(1), c = 1 099.9(1) pm, β = 126.59(1)°, V = 0.9769(1) nm3, Co: a = 1 462.5(2), b = 756.5(2), c = 1 102.2(2) pm, β = 126.53(1)°, V = 0.9798(2) nm3, Ni: a = 1 452.2(2), b = 751.0(1), c = 1 091.5(1) pm, β = 126.28(1)°, V = 0.9595(1) nm3, Zn: a = 1 468.3(2), b = 755.8(1), c = 1 103.1(1) pm, β = 126.79(1)°, V = 0.9804(2) nm3. The crystal structures consist of hexagonal packed [M(HSeO3)2 · 2H2O]n chains of [MO4(H2O)2] octahedra linked by Se atoms. They contain trigonal pyramidal SeO2OH?ions with “free” hydroxyl groups and also “free” molecules of water of crystallization. The hydroxyl groups build strong H-bonds (O? H …? O distances: 265–268 pm). The IR spectra show AB doublett bands in the OH stretching mode region of the hydroxyl groups. The water molecules of crystallization are linked to planar (H2O)4 tetramers by H-bonds with unusually short O? H …? O bond distances of 271–273 pm. DTA and TG measurements indicate that thermal decomposition results in the direct formation of the respective diselenite MSe2O5. Raman heating measurements show under quasi static conditions the intermediate formation of the anhydrous hydrogen selenites. 相似文献
987.
Breuer U Holzbrecher H Gastel M Becker JS Dietze HJ 《Analytical and bioanalytical chemistry》1995,353(3-4):372-377
For the quantification of heterostructure depth profiles the knowledge of relative sensitivity factors (RSF) and the influence of matrix effects on the measured profiles is necessary. Matrix dependencies of the measured ion intensities have been investigated for sputtered neutral mass spectrometry (SNMS) and MCs(+)-SIMS. The use of Cs as primary ions for SNMS is advantageous compared to Ar because the depth resolution is improved without changing RSFs determined under Ar bombardment. No significant amount of molecules has been found in the SNMS spectra under Cs bombardment. Using MCs(+)-SIMS the RSFs are matrix dependent. An improvement of depth resolution can be achieved by biasing the sample against the primary ion beam for SNMS due to a reduction of the net energy of the primary ions and a resulting more gracing impact angle. 相似文献
988.
S. Cattarin M.M. Musiani U. Casellato P. Guerriero R. Bertoncello 《Journal of Electroanalytical Chemistry》1995,380(1-2)
In+As+Sb alloys have been deposited onto Ni and Ti cathodes from tartaric acid solutions at pH 2. Homogeneous deposits of composition suitable for achieving InAsxSb1−x can be obtained from this medium. The As-to-Sb ratio can be controlled by properly selecting solution composition and deposition potential.X-ray photoelectron spectroscopy and X-ray diffraction analyses show that formation of III–V compounds occurs at room temperature. In reacts preferentially with As rather than with Sb, but crystalline phases formed at room temperature are Sb-rich. After annealing the In+As+Sb alloys at 250°C, the composition calculated from cell parameters appears similar to that measured by energy-dispersive X-ray analysis, suggesting that the entire deposit has been converted into the InAsxSb1−x crystalline phase. 相似文献
989.
Cr(III) slowly forms a violet complex with EDTA at pH 3.5 +/- 0.2 under normal conditions. The complex formation can be catalyzed by irradiating the reacting mixture with ultrasonic waves. Quantitative formation of the complex was possible with ultrasonic waves of 15 W/cm(2) intensity within 7.5 min of sonication. This method may be successfully applied to the determination of chromium in ores and beneficiated products containing 20-60% Cr(2)O(3) without separating the analyte from the matrix elements. 相似文献
990.
Weiss VU Subirats X Pickl-Herk A Bilek G Winkler W Kumar M Allmaier G Blaas D Kenndler E 《Electrophoresis》2012,33(12):1833-1841
During infection, enteroviruses, such as human rhinoviruses (HRVs), convert from the native, infective form with a sedimentation coefficient of 150S to empty subviral particles sedimenting at 80S (B particles). B particles lack viral capsid protein 4 (VP4) and the single-stranded RNA genome. On the way to this end stage, a metastable intermediate particle is observed in the cell early after infection. This subviral A particle still contains the RNA but lacks VP4 and sediments at 135S. Native (150S) HRV serotype 2 (HRV2) as well as its empty (80S) capsid have been well characterized by capillary electrophoresis. In the present paper, we demonstrate separation of at least two forms of subviral A particles on the midway between native virions and empty 80S capsids by CE. For one of these intermediates, we established a reproducible way for its preparation and characterized this particle in terms of its electrophoretic mobility and its appearance in transmission electron microscopy (TEM). Furthermore, the conversion of this intermediate to 80S particles was investigated. Gas-phase electrophoretic mobility molecular analysis (GEMMA) yielded additional insights into sample composition. More data on particle characterization including its protein composition and RNA content (for unambiguous identification of the detected intermediate as subviral A particle) will be presented in the second part of the publication. 相似文献