全文获取类型
收费全文 | 40篇 |
免费 | 1篇 |
专业分类
化学 | 26篇 |
物理学 | 15篇 |
出版年
2018年 | 1篇 |
2015年 | 1篇 |
2013年 | 1篇 |
2012年 | 3篇 |
2011年 | 1篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2001年 | 1篇 |
1994年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1970年 | 2篇 |
1960年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1955年 | 2篇 |
1943年 | 1篇 |
1939年 | 1篇 |
排序方式: 共有41条查询结果,搜索用时 203 毫秒
1.
F. Meyer J. Dupré C. Meyer C. Lambeau M. De Vleeschouwer J. -G. Lahaye A. Fayt 《International Journal of Infrared and Millimeter Waves》1982,3(1):83-95
The 5 band of methylacetylene has been studied simultaneously by means of CO2 Laser Stark spectroscopy and high resolution infrared absorption spectroscopy (0.012 cm–1). The primary aim of this work was to assign all the Stark coïncidences. Effective vibration-rotation parameters and the dipole moment of the v5=1 state have been determined. 相似文献
2.
In the TAS procedure, substances which can be separated from a sample by thermal increase of the vapour pressure can be transported to the TLC layer in different ways and with varying effectiveness. “Forced Convection” gives the lowest yields, results improve considerably with the so-called carrier gas extraction, and a carrier gas extraction in a stream of helium results in optimal yields. Nipagin®, Sudan red, Dimethyl yellow, Menadione® and Diphenyl were used as model substances. An almost quantitative thermoextraction from samples can only be achieved with amounts of less than 20 μg. Following scraping off and elution of the corresponding TLC-zones a photometric assay is carried out for quantitative determination. 相似文献
3.
Direct determination of the alkali metal output of glass ampoules by atomic emission and absorption spectrometry is described. The methods provide suitable alternatives to acidimetric titration for characterizing the hydrolytic resistance of container glasses for pharmaceutical use. 相似文献
4.
Jixin Qiao Petra Lagerkvist Ilia Rodushkin Susanna Salminen-Paatero Per Roos Syverin Lierhagen Karl Andreas Jensen Emma Engstrom Yann Lahaye Lindis Skipperud 《Journal of Radioanalytical and Nuclear Chemistry》2018,315(3):565-580
Inductively coupled plasma mass spectrometry (ICP-MS) techniques are widely used for determination of long-lived radionuclides and their isotopic ratios in the nuclear fields. Uranium (U) and Plutonium (Pu) isotopes have been determined by many researchers with ICP-MS due to its relatively high sensitivity and short measurement time. In this work, an inter-laboratory comparison exercise among the Nordic countries was performed, focusing on the measurement of U and Pu isotopes in certified reference materials by ICP-MS. The performance and characters of different ICP-MS instruments are evaluated and discussed in this paper. 相似文献
5.
Christoph Bttcher Edda von Roepenack‐Lahaye Jürgen Schmidt Stephan Clemens Dierk Scheel 《Journal of mass spectrometry : JMS》2009,44(4):466-476
Total phenolic choline ester fractions prepared from seeds of Arabidopsis thaliana and Brassica napus were analyzed by capillary LC/ESI‐QTOF‐MS and direct infusion ESI‐FTICR‐MS. In addition to the dominating sinapoylcholine, 30 phenolic choline esters could be identified based on accurate mass measurements, interpretation of collision‐induced dissociation (CID) mass spectra, and synthesis of selected representatives. The compounds identified so far include substituted hydroxycinnamoyl‐ and hydroxybenzoylcholines, respective monohexosides as well as oxidative coupling products of phenolic choline esters and monolignols. Phenolic choline esters are well separable by reversed‐phase liquid chromatography and sensitively detectable using electrospray ionization mass spectrometry in positive ion mode. CID mass spectra obtained from molecular ions facilitate the characterization of both the type and substitution pattern of such compounds. Therefore, LC/ESI‐MS/MS represents a valuable tool for comprehensive qualitative and quantitative analysis of this compound class. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
6.
Zusammenfassung Die vorliegende Abhandlung besch?ftigt sich mit der Erforschung der Zusammenh?nge zwischen Flie?eigenschaften und Temperatur.
Nach eingehender Diskussion der verschiedenen Flie?kurventypen werden die Flie?kurvendiagramme von 4 Polyvinylazetaten besprochen
und der Begriff der Verformungsleistung entwickelt. Die Abh?ngigkeit der Verformungsleistung von der Temperatur kann durch
eine ?hnliche Gleichung dargestellt werden, wie sie von Andrade und Sheppard für die Temperaturabh?ngigkeit der Viskosit?t
angegeben wurde. Dadurch wird eine allgemeinere Auswertung von Flie?kurvendiagrammen m?glich.
Die Verfasser danken dem Direktor der Reichsforschungsanstalt für Kleintierzucht, Herrn Prof. Dr. A. Koch, für sein wohlwollendes
und stets f?rderndes Interesse an der Aufdeckung der mitgeteilten Zusammenh?nge. Wir danken der Firma Dr. Alexander Wacker,
München, für die überlassung der verschiedenen Polyvinylazetate sowie Herrn Generaldirektor Wilke, Mitteldeutsche Spinnhütte
G. m. b. H., Celle, für die Bereitstellung eines Ultrathermostaten. Unser Dank gilt ferner der Deutschen Forschungsgemeinschaft,
die ein Konsistometer zur Verfügung stellte. 相似文献
7.
8.
A water-soluble manganese porphyrin, 5,10,15,20-tetrakis-(1,3-dimethylimidazolium-2-yl)porphyrinatomanganese(III) (Mn(III)TDMImP) is shown to react with H(2)O(2) to generate a relatively stable dioxomanganese(V) porphyrin complex (a compound I analog). Stopped-flow kinetic studies revealed Michaelis Menton-type saturation kinetics for H(2)O(2). The visible spectrum of a compound 0 type intermediate, assigned as Mn(III)(OH)(OOH)TDMImP, can be directly observed under saturating H(2)O(2) conditions (Soret band at 428 nm and Q bands at 545 and 578 nm). The rate-determining O-O heterolysis step was found to have a very small activation enthalpy (ΔH(≠) = 4.2 ± 0.2 kcal mol(-1)) and a large, negative activation entropy (ΔS(≠) = -36 ± 1 cal mol(-1) K(-1)). The O-O bond cleavage reaction was pH independent at 8.8 < pH < 10.4 with a first-order rate constant of 66 ± 12 s(-1). These observations indicate that the O-O bond in Mn(III)(OH)(OOH)TDMImP is cleaved via a concerted "push-pull" mechanism. In the transition state, the axial (proximal) (-)OH is partially deprotonated ("push"), while the terminal oxygen in (-)OOH is partially protonated ("pull") as a water molecule is released to the medium. This mechanism is reminiscent of O-O bond cleavage in heme enzymes, such as peroxidases and cytochrome P450, and similar to the fast, reversible O-Br bond breaking and forming reaction mediated by similar manganese porphyrins. The small enthalpy of activation suggests that this O-O bond cleavage could also be made reversible. 相似文献
9.
R.J.W.E. Lahaye 《Surface science》2010,604(13-14):1135-1142
This is a study into the scattering dynamics of the alkaline ions Cs+, K+, Na+, and Li+ from an ice surface, and the process of abstracting water molecules by the scattered ions to form ion–water clusters as a result of the ion–dipole attraction. In a classical molecular dynamics computer simulation a semi-empirical ion–water interaction potential and a modified version of the TIP3P ice model are employed.The thickness of the ice structure at the surface greatly affects the abstraction efficiency. From a thin ice overlayer all alkaline ions exhibit similar scattering probabilities, but Cs+ abstracts water molecules most efficiently; its lower speed facilitates a mechanism where the Cs+ in its outgoing trajectory pulls water molecules out of the ice structure. From a thick ice structure the scattering probabilities decrease dramatically due to an effective energy transfer to the ice structure. A more grazing angle of incidence reduces the energy transfer and enhances the scattering probabilities for the lighter alkaline ions. The deprived formation of ion–water clusters in the simulations confirms that from thick ice the cluster formation probability is reduced by at least three orders of magnitude. 相似文献
10.
A. Fayt J. G. Lahaye J. Lemaire F. Herlemont J. G. Bantegnie 《Journal of Molecular Spectroscopy》1990,140(2)
Heterodyne spectra of carbonyl sulfide have been obtained with saturation in a CO2 waveguide laser and without saturation with a diode laser. The absolute uncertainties of the measured positions lie between 10−4 and 7 × 10−6 cm−1. The CW submillimeter laser line of OCS at 378 μm has been assigned to the J = 65 → 64 transition in the 0220e state of 16O12C32S, with a pumping through the R(64) line of 0220e ← 0000, a Δ-Σ transition weakly allowed by the l-type resonance. 相似文献