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11.
Jacquelynn L. Savoca Robert P. Lattimer Joseph M. Richards Willem Windig Henk L.C. Meuzelaar 《Journal of Analytical and Applied Pyrolysis》1985,9(1):19-28
A set of twelve natural rubber vulcanizates was analyzed by Curie-point pyrolysis-mass spectrometry (Py-MS). Multivariate analysis successfully correlated the Py-MS data with either total or polysulfidic crosslink density measurements. (Polysulfidic means two or more sulfurs.) The principal correlation observed was an increase in the ratio of monomer to dimer pyrolyzate yield with an increase in crosslink density. The feasibility of using Py-MS for total crosslink density determination has thus been demonstrated. The Py-MS data, however, did not allow us to distinguish different types of crosslinks. 相似文献
12.
Floris P. J. T. Rutjes Henk Hiemstra Hendrik H. Mooiweer W. Nico Speckamp 《Tetrahedron letters》1988,29(52):6975-6978
Acid catalyzed cyclization of methoxymethyl substituted acyclic hydrazides 4 provides cyclic hydrazides 5 in moderate to good yields through the intermediacy of N,N′-di(methoxycarbonyl)hydrazinium intermediates. 相似文献
13.
Saalfrank RW Deutscher C Maid H Ako AM Sperner S Nakajima T Bauer W Hampel F Hess BA van Eikema Hommes NJ Puchta R Heinemann FW 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(8):1899-1905
In the reaction of the N-substituted diethanolamines (H(2)L(1-3)) (1-3) with calcium hydride followed by addition of iron(III) or indium(III) chloride, the iron wheels [Fe(6)Cl(6)(L(1))(6)] (4) and [Fe(6)Cl(6)(L(2))(6)] (6) or indium wheels [In(6)Cl(6)(L(1))(6)] (5), [In(6)Cl(6)(L(2))(6)] (8) and [In(6)Cl(6)(L(3))(6)] (9) were formed in excellent yields. Exchange of the chloride ions of 6 by thiocyanate ions afforded [Fe(6)(SCN)(6)(L(2))(6)] (7). Whereas the structures of 4, 5 and 7 were determined unequivocally by single-crystal X-ray analyses, complexes 8 and 9 were characterised by NMR spectroscopy. Contrary to what is normally presumed, the scaffolds of six-membered metallic wheels are not generally rigid, but rather undergo nondissociative topomerisation processes. This was shown by variable temperature (VT) (1)H NMR spectroscopy for the indium wheel [In(6)Cl(6)(L(1))(6)] (5) and is highlighted for the enantiotopomerisation of one indium centre [ 1/6[S(6)-5]<==>[1/6[S(6)-5']]. The self-assembly of metallic wheels, starting from diethanolamine dendrons, is an efficient strategy for the convergent synthesis of metallodendrimers. 相似文献
14.
Henk Buck 《International journal of quantum chemistry》2005,101(1):73-83
With semi‐empirical MO and ab initio calculations at different levels, we investigated the π conjugation of alternating X? Y bonds with X? Y for N/B and N/C combinations in an open and cyclic arrangement. Although the intrinsic symmetry is lost for the acyclic even‐membered compounds, the alternation is still reflected in its geometry and electron‐density transfer. For the cyclic π compounds, we focused our attention on borazine N3B3H6 (D3h symmetry), which is isoelectronic with benzene (D6h symmetry). Specific attention is given to the electrophilic behavior of borazine with respect to CH and SiMe. The dynamics based on the results of FT‐ICR mass spectrometry was studied in more detail. In addition, the results of the cyclic systems with 4n and 4n+2 π electrons concerning their geometries are compared with the corresponding carbon compounds. Attention is also given to the dication of borazine, because of the corresponding triplet ground state of the benzene dication. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 相似文献
15.
Neil S. Arnold Cyorgy Hars Henk L. C. Meuzelaar 《Journal of the American Society for Mass Spectrometry》1994,5(7):676-688
Proceeding from the pseudopotential-well approximation for ion motion in a quadrupole ion trap, mathematical expressions are derived to describe the excitation amplitude of an ion packet at a given mass-to-charge ratio. Ion-neutral collisions are incorporated to describe the damping of ion trajectories and to describe the distribution of individual ion trajectories about a mean amplitude for the ion packet. The rate of increase of the amplitude during scanning is related to expressions that describe the amplitude dispersion of the ions at the time of ejection from the trap, which is operating in a resonance ejection scanning mode to describe the temporal line width of the ejected ion packet. The temporal line width is related to mass resolution under a number of different scanning conditions. Included in the discussion are considerations of the effect on resolution of the resonance excitation voltage, temperature, pressure, noise, and buffer-gas composition. An expression for the maximum possible resolution at high ion mass-to-charge ratios is developed, and these results are compared to an existing theoretical construction. The expressions derived under the pseudopotential-well approximation are further extended to high q z values and compared to experimental data previously published by two other researchers. 相似文献
16.
Rozing G van de Goor T Yin H Killeen K Glatz B Kraiczek K Lauer HH 《Journal of separation science》2004,27(17-18):1391-1401
A systematic investigation of the influence of the perimeter shape of open and particle packed fused silica capillaries on chromatographic properties such as resistance to flow and dispersion of solutes propelled through these channels has been conducted. Verifications of these uncommon experiments with existing theoretical treatments are presented and the insights transferred to a novel polymer chip design with integrated facilities for complex separations. A comparison of the chromatographic performance of a real life proteomics sample on this chip with a capillary column of "similar" dimensions is presented. 相似文献
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19.
David D. Díaz Henk J. Bolink Luca Cappelli Eugenio Coronado 《Tetrahedron letters》2007,48(27):4657-4660
A series of new light emitting subphthalocyanines, lower homologues of phthalocyanines, were synthesized having color points covering the red-orange region of the visible spectrum. Additionally, they were found to be of potential use as narrow band emitters for red-light emitting diodes. 相似文献
20.
René Grouls Wim van de Laar Henk M. J. Goldschmidt Frits G. van Merode 《Accreditation and quality assurance》2004,10(1-2):41-46
Many medical professionals are involved in patient care processes. For pharmaceutical care this results in many information transfer moments. To provide optimal care, communication and information the transfer should be conducted in a timely manner, fully transparent, complete and relevant. The TRANSFORM project is directed towards the development of a reference information model of the pharmaceutical care chain with the aim to improve the availability (time, place, completeness) and access of pharmaceutical information regarding patients, thereby resulting in continuity and quality of pharmaceutical care, reduction in medical errors and improvement in patient safety through the design of a safer healthcare system. TRANSFORM leads to improved insight into the processes and data transfer points in the pharmaceutical chain of care. Focussed on laboratory medicine and pharmacy, the implementation of the integration of laboratory test and pharmacy information may result in major improvements in drug therapy monitoring and guidance (i.e. drug impact monitoring). Because of the overwhelming amount of data generated by this integration of drugs, drug effects and laboratory test results, an online decision support system is warranted.Presented at the 9th Conference on Quality in the Spotlight, 18–19 March 2004, Antwerp, Belgium.The following paper may appear at first sight not to be specifically within the realm of ACQUAL. It has been accepted for publication anyway as it is about reliable handling of data, incl. measurement results, which lead to important decisions (in this case related to a patient). The reliability of handling (a large amount of) measurement results towards a basis for important decisions, is a very important feature of the use of such results.Paul De Bièvre, Editor in Chief 相似文献