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991.
992.
气相色谱质谱联用仪与微机的数据传输和处理 总被引:1,自引:0,他引:1
报道了一种用于气相色谱质谱联用仪和微机之间实现数据传输和处理的方法。方法可更有效地利用质谱仪采集的数据,解决了工作站处理数据的局限性。经数据格式转换,原始数据可以在微机上实现色谱峰再现,从而为色谱条件的优化和定量数据处理创造了条件。 相似文献
993.
L.A. Isupova I.S. Yakovleva I.I. Gainutdinov Yu.T. Pavlyukhin V.A. Sadykov 《Reaction Kinetics and Catalysis Letters》2004,81(2):373-382
The phase composition and microstructure of samples of the La1-xCaxFeO3-y system prepared via a ceramic route were characterized by M?ssbauer spectroscopy. In all cases, iron was found in the 3+ state. The ordering
of anion vacancies in the samples with the composition in the range of 0.8 > x ≥ 0.4, which corresponds to a microheterogeneous
solid solution, generates new distorted octahedral and fivefold/tetrahedral sites revealed by two typical sextets. The disordering
of this solid solution and small (10-100 ?) sizes of domains with a perovskite, braunmillerite or Grenier phase structure
caused the appearance of a superparamagnetic doublet, which grows with the Ca content up to x = 0.8 but disappears in the
sample of pure braunmillerite. The appearance of Fe cations in a distorted coordination correlates with the increased activity
of the samples with a microheterogeneous structure in the CO catalytic oxidation and with their reducibility by H2.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
994.
Summary Chemiluminescent reactions of ozone with several classes of compounds at different temperatures are described. In a reaction chamber in front of a photomultiplier ozone is mixed with the compounds studied such as alkanes, olefins, alcohols, aromatics, C2H2, NO, vinyl chloride or H2S. The chemiluminescent emission is proportional to the concentration of the compound involved. At room temperature only olefinic hydrocarbons respond but at temperatures above 150°C also a response for alkanes, alcohols, CO etc. is obtained. It is suggested that next to the ozonide-excited formaldehyde mechanism the CO-CO
2
*
mechanism is responsible for the chemiluminescent emission at high temperature. A detection limit of a few ppb is achieved. Possible applications are a selective gas-chromatographic detector, an air pollution monitor for instance for CO, and a photochemical reactivity monitor.
Bestimmung reaktiver Kohlenwasserstoffe durch Chemiluminescenz
Zusammenfassung Chemiluminescenzreaktionen von Ozon mit verschiedenen Verbindungsgruppen (hauptsächlich Kohlenwasserstoffe) bei unterschiedlichen Temperaturen werden beschrieben. In einer Reaktionskammer werden die Verbindungen vor einem Photomultiplier mit Ozon vermischt. Es handelt sich u. a. um folgende Verbindungstypen: Alkane, Olefine, Alkohole, Aromaten, C2H2, NO, Vinylchlorid, H2S. Die Emissionsintensität ist proportional der Konzentration. Bei Raumtemperatur sprechen nur Olefine an, die übrigen Verbindungen erst über 150°C. Die Emission bei höherer Temperatur wird neben der Bildung von Formaldehyd auf die Reaktion CO-CO 2 * zurückgeführt. Die Nachweisgrenze beträgt wenige ppb. Als mögliche Anwendungsgebiete werden ein selektiver GC-Detektor, ein Monitor für Luftverunreinigungen (z.B. für CO) sowie ein Monitor zur Messung photochemischer Reaktivität der Luft genannt.
Presented at the 6th Annual Symposium on Recent Advances in the Analytical Chemistry of Pollutants, April 21–23, 1976; Vienna, Austria. 相似文献
995.
The physico-chemical properties of a catalyst containing 90% Al2O3, 9% Cr2O3 and 1% Fe2O3 have been studied. Coexistence of acidic and basic (ionic) sites as well as electron acceptor radical centers have been found.
- : 90% Al2O3, 9% Cr2O3 1% Fe2O3. , () , - .相似文献
996.
乙酰化淀粉/DL-丙交酯接枝共聚物的合成及降解性能研究 总被引:7,自引:0,他引:7
用醋酸乙烯酯和玉米淀粉反应制备出了不同取代度乙酰化淀粉,再用乙酰化淀粉同DL-丙交酯接枝共聚合成乙酰化淀粉/DL-丙交酯接枝共聚物。研究了原料配比,淀粉取代度对接枝反应单体转化率(C%),接枝率(G%)接枝效率(GE%)和接枝支链数均分子量(Mn)的影响,结果表明在给定的试验条件下接枝共聚反应的C%,G%,GE%和Mn可分别达到40%,225%,80%和1.4万。接枝共聚物在磷酸缓冲溶液和户外土壤掩埋降解实验表明,在160天内样品失重率分别为71%和60%,表明合成的乙酰化淀粉/DL-丙交酯接枝共聚物具有很好的降解性能。 相似文献
997.
998.
J. C. Masini Oswaldo E. S. Godinho Luiz M. Aleixo 《Fresenius' Journal of Analytical Chemistry》1998,360(1):104-111
A linearization method based on modified Gran functions, and a general nonlinear regression program were used to study potentiometric
titration curves of denatured ovalbumin and lysozyme in 6 mol L–1 guanidine hydrochloride medium with the aim of determining the ionizable species. With both numerical techniques it was possible
to determine the sum of the carboxylic groups, the imidazol, the α-amine, and the sum of ɛ-amine, phenolic and sulfhydryl
groups, if the protein is completely denatured, and assumes a randomly coiled conformation. A total of 87.8 ± 2.5 and 20.7
± 0.6 groups per mol were determined in the ovalbumin and lysozyme, respectively. These values are very close to the 88 and
21 groups expected by aminoacid composition of both proteins, indicating that all ionizable groups were exposed to the solvent.
For ovalbumin the distribution of groups was very similar to that expected by the aminoacid composition, but for lysozyme
some anomalies were observed, suggesting the existence of interactions between ionizable groups, altering the dissociation
constants.
Received: 9 December 1996 / Revised: 27 February 1997 / Accepted: 4 March 1997 相似文献
999.
R. Bontchev K. Cheshkova D. Mehandjiev J. Darriet 《Reaction Kinetics and Catalysis Letters》1998,63(1):121-127
The catalytic activity of Ba2Ru0.67Bi1.33O6, Ba2RuBiO6, Ba3Ru2BiO9 and BaRuO3 towards NO-decomposition prior to and after treatment with NH3 has been studied. About 100% degree of conversion has been achieved at 400°C for samples with the highest percentage of hexagonal
stacking in their crystal structures. It has been shown that the active sites are units of two or three face-sharing [RuO6] octahedra in which a strong Ru−Ru interaction takes placevia the common faces. 相似文献
1000.
二氧化碳溶剂浮选光度法测定高碘蛋总碘量 总被引:5,自引:1,他引:5
浮选法是二氧化碳气氛中,以溴化十六烷基三甲基铵(CTMAB)为捕收剂,用溶剂浮选吸光光度法对离子缔合物(CTMA~ I_3~-)的组成进行测定。试验表明,方法有较高的灵敏度,较好的准确性和重现性。 相似文献