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Brivio M Tas NR Goedbloed MH Gardeniers HJ Verboom W van den Berg A Reinhoudt DN 《Lab on a chip》2005,5(4):378-381
The integration of a monitoring port along the microfluidic path of a MALDI-chip integrated device is described. Optimization of the microreactor design allows longer reaction and measuring times. The Schiff base reaction between 4-tert-butylaniline (1) and 4-tert-butylbenzaldehyde (2) in ethanol was carried out on-chip in the MALDI ionization chamber and the formed imine 3 was detected in real time, demonstrating the feasibility of the "monitoring window" approach. This preliminary result opens the way to on-chip kinetic studies by MALDI-MS, by opening multiple monitoring windows along the microchannel. 相似文献
13.
Ahmet Kilic Cezmi Kayan Murat Aydemir Feyyaz Durap Mustaf Durgun Akn Baysal Esref Tas Bahattin Gümgüm 《应用有机金属化学》2011,25(5):390-394
Two new boron complexes were synthesized from N‐[3‐(methylmercapto)aniline]‐3,5‐di‐tert‐butylsalicylaldimine ( LH ) with boron reagent BPh3 or BF3.Et2O. These boron complexes are stable and easily soluble in protic solvents such as ethanol (C2H5OH) but hardly soluble in nonprotic solvents such as chloroform (CHCl3), dichloromethane (CH2Cl2) and tetrahydrofuran (THF). All new boron complexes have been fully characterized by both analytical and spectroscopic methods. The catalytic activities of complexes [LBPh2], 2 , and [LBF2], 3 , in the transfer hydrogenation of acetophenone derivatives were tested. Stable boron complexes were found to be efficient catalysts in the transfer hydrogenation of aromatic ketones in good conversions up to 99% in the presence of iso‐PrOH/KOH. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
14.
In this paper we define strong A-convergence with respect to an Orlicz function for double sequences. We show, on bounded double sequences, that statistical convergence and strong A-convergence with respect to any Orlicz function are equivalent. This eliminates a condition of Demirci for bounded single (ordinary) sequences. 相似文献
15.
Reactions of NO in a Positive Streamer Corona Plasma 总被引:2,自引:0,他引:2
Tas Marnix A. van Hardeveld R. van Veldhuizen E. M. 《Plasma Chemistry and Plasma Processing》1997,17(4):371-391
The reaction of NO in a streamer corona plasma is studied systematically as a function of the composition of the gas mixture, the initial concentration of NO, and the discharge repetition rate. The experimental results show that the reactions of NO depend strongly on the composition of the gas mixture. Reduction is observed in the absence of oxidants such as oxygen and water, but at very high energy cost (>200 eV/NO). In the presence of both these oxidants, more than 90% of the NO conversion is oxidation. The lowest energy costs, 24 eV/NO for He mixtures and 45 eV/NO for N
2
mixtures, are obtained at water and oxygen concentration above 3% and at low discharge repetition rates (<10 Hz). Chemical kinetics calculations of the production of radicals in the plasma show a good agreement with the value derived from the experiments. 相似文献
16.
New Schiff-base copper and cobalt complexes, [Cu(L1)], [Cu(L2)] and [Co(L1)], [Co(L2)] (where L1 = N-N′-bis(3,5-di-tert-butylsalicylaldimine)-1,4-cyclohexane bis(methylamine) and L2 = N-N′-bis(3,5-di-tert-butylsalicylaldimine)-1,8-diamino-3,6-dioxaoctane), were synthesized and characterized using elemental analysis, IR spectra, UV–Vis spectra, magnetic susceptibility measurements, 1H and 13C NMR spectroscopy, thermal analysis and molar conductance (ΛM). Their electro-spectrochemical properties were investigated using cyclic voltammetric (CV) and thin-layer spectroelectrochemical techniques in a dichloromethane solution (CH2Cl2). The CV of [Cu(L2)] showed a lower oxidation potential than that of [Cu(L1)] under the same experimental conditions. The oxidation wave (II) of [Cu(L2)] was accompanied by an EC process (II′), which was not observed for [Cu(L1)]. Also, [Cu(L2)] exhibited a reduction process, but [Cu(L1)] did not. These results indicate that the Cu(II) ion in [Cu(L2)] is coordinated by N2O4 donor sites while [Cu(L1)] presents a square-planar structure with N2O2 donor sites. Both oxidation processes for [Co(L1)] and [Co(L2)] are based on the cobalt center, and they are assigned to Co(II)/Co(III) couples. The spectroelectrochemical results indicate that the oxidized species of [Cu(L2)] is similar to that of [Cu(L1)], the only difference being that the absorption bands of the oxidized species for [Cu(L2)] shift to lower energy compared with those of [Cu(L1)] because of their different coordination environment. The geometry of [Cu(L2)] changed into square-planar after the complex was totally oxidized and the neutral complex was only recovered following the EC process, as observed from the CV of [Cu(L2)]. For the two cobalt complexes, the bands corresponding to the π → π∗transitions disappeared and new bands with small red shifts and of lower intensity were observed during the oxidation process. These new bands are attributed to the LMCT transition as observed in the case of the oxidation processes of the cobalt complexes. 相似文献
17.
Derivatization and mass spectrometric behaviour of catecholamines and their 3-O-methylated metabolites 总被引:1,自引:0,他引:1
A C Tas J Odink M C ten Noever de Brauw J Schrijver R J Jonk 《Journal of chromatography. A》1984,310(2):243-250
A method has been developed for the derivatization of both catecholamines (dopamine, noradrenaline and adrenaline) and their 3-O-methylated metabolites (3-methoxytyramine, normetanephrine and metanephrine) in a single run. The compounds were first incubated with methanolic hydrochloric acid to methylate those compounds that contain a benzylic hydroxyl group and were subsequently converted into their pentafluoropropionyl derivatives. The derivatives thus prepared, showed good gas chromatographic and electron-impact mass spectrometric properties and can be analysed in a single gas chromatographic run. The effect of the derivatization on exchange reactions in the aromatic ring was investigated because standard compounds with deuterium label in that part of the molecule are often used in isotope dilution measurements. The exchange of deuterium for hydrogen in the aromatic ring under derivatization conditions was found to be limited. 相似文献
18.
Salvador J. Pastor Tas Dienes Jie Yao Charles L. Wilkins 《Journal of the American Society for Mass Spectrometry》1998,9(9):931-937
Low-voltage on-resonance ion selection (LOIS) was recently introduced as an alternative technique for ion selection and storage. Under high pressure conditions and similar to the technique of quadrupolar axialization, unwanted (unselected) trapped ions are eliminated from the analysis cell through collisions with cell plates following orbital expansion. The ions remaining after tens of seconds of mass selection can be detected with better coherence, leading to improvements in ion detection and sensitivity. Here, experiments designed to test ion remeasurement and ion transfer capabilities are presented. Simulations of ion motion give insight into the possible mechanism of ion cooling, which does not appear to be the same as that of the axialization process. Because of its ease of use, lack of need for additional hardware devices, and comparable ion selection results, LOIS is an attractive alternative for trapped ion experiments. 相似文献
19.
The ligand containing the 4‐amino‐1‐benzyl piperidine group, N, N′‐(4‐amino‐1‐benzyl piperidine)‐glyoxime, (LH2) (1) was prepared from 4‐amino‐1‐benzyl piperidine with anti‐dichloroglyoxime at ? 15 °C in absolute Tetrahydrofuran (THF). In the trinuclear [Pd(L)2Ru2(phen)4](ClO4)2 (4) and [Pd(L)2Ru2(bpy)4](ClO4)2 (5) metal complexes, the PdII ion centered into the main oxime core by the coordination of the imino groups while the two RuII ions coordinated dianionic oxygen donors of the oxime groups and linked to the ligands of 1,10‐phenanthroline and 2,2′‐bipyridine. The mono and trinuclear metal complexes were characterized by elemental analyses, FT‐IR, UV–vis, 1H and 13C‐NMR spectra, magnetic susceptibility measurements, molar conductivity, cyclic voltammetry, mass spectra, X‐ray powder techniques and their morphology by SEM measurements. The cyclic voltammetric results show that the cathodic peak (Epc) potential of (3) shifts towards more positive values compared with that of (2) as a result of the BPh2+‐bridged complex formation. The Suzuki–Miyaura reaction was used to investigate their activity as catalyst either prepared in‐situ or from well‐defined complexes. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Mela P Tas NR Berenschot EJ van Nieuwkasteele J van den Berg A 《Electrophoresis》2004,25(21-22):3687-3693
Electrokinetic pumping of low-volume rates was performed on-chip in channels of small cross sectional area and height in the sub-microm range. The flow was detected with the current monitoring technique by monitoring the change in resistance of the fluid in the channel upon the electroosmosis-driven displacement of an electrolyte solution by a second electrolyte solution. Flow rates in the order of 0.1 pL/s were successfully generated and detected. The channels were fabricated with the sacrificial layer technology. 相似文献