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排序方式: 共有732条查询结果,搜索用时 15 毫秒
131.
Chi Wu Klaus Unterforsthuber Dieter Lilge Erik Lüddecke Dieter Horn 《Particle & Particle Systems Characterization》1994,11(2):145-149
Laser light scattering (LLS), especially dynamic laser light scattering (DLS), also known as photon correlation spectroscopy (PCS), is a well established method for particle size distribution analysis. It usually involves a Laplace inversion of the field autocorrelation function. However, the resolution is limited because of the ill-conditioned nature of this Laplace inversion. No unique solution exists when noise is present on the data. In contrast with this ill-conditioned nature, the angular dependence of scattered (static) intensities is precisely not ill-conditioned, which allows the resolution of the ill-conditioned inversion of DLS data to be improved. In order to characterize samples with more complicated size distributions, an intensityconstrained multi-angle PCS data analysis program has been developed, which is an alternative way of normalizing the field correlation function to that reported by Cummins and Staples [12]. In this program, the field autocorrelation function is normalized to the scattering intensity by using a predetermined coherent factor at each angle, which provides an additional constraint on the Laplace inversion of multi-angle PCS data analysis. The alternative analysis improves the resolution of PCS and provides a more reliable particle size distribution than single-angle data analysis. Both simulated and measured LLS data are used to illustrate its application, resolution and limitations. 相似文献
132.
Franz Maximilian Horn 《Fresenius' Journal of Analytical Chemistry》1888,27(1):163-165
Ohne ZusammenfassungAssistent an der K. K. technischen Hochschule in Wien. 相似文献
133.
The chemisorption of Li and Na on clean and oxygen covered polycrystalline iridium was investigated using nuclear spin polarized alkali atoms. During adsorption on the surface the moments of the nuclei act as microscopic probes. The nuclear quadrupole moments of the alkali atoms are interacting with the electric field gradient. The interaction reflects the charge distribution around the nucleus. The nuclear magnetic moments are interacting with magnetic fields generated by the magnetic moments of electrons. 相似文献
134.
Michalek F Horn J Tzschucke CC Bannwarth W 《Combinatorial chemistry & high throughput screening》2003,6(7):729-740
Supported catalysts have become valuable tools for simplified product isolation and catalyst recycling. The common method is covalent attachment to a solid support. An alternative strategy is to immobilize catalysts by non-covalent bonding through hydrogen bridges, ionic, hydrophobic or fluorous interactions. Compared to covalent attachment, such non-covalent approaches increase the flexibility in the choice of the support-material, reaction conditions and work-up strategies. Numerous catalytic reactions employing one of these non-covalent fixation strategies have meanwhile appeared in the literature. 相似文献
135.
Zusammenfassung Die beiden Reaktionen (1) PbR4+HacR3Pbac+HR, (2) R3Pbac+HacR2Pbac
2+HR laufen bei der Umsetzung von Pb(C2H5)4 und Essigsäure in wasserfr. Toluol bei 60°, 80° und 100° als konkurrierende Folgereaktionen 2. Ordnung ab. Der Reaktionsablauf wurde durch Titration der Essigsäure mit KOCH3-Lösung in wasserfr. Medium verfolgt, wobei die Geschwindigkeitskonstanten und die Aktivierungsenergien der Reaktionen ermittelt wurden.
Mit 9 Abbildungen.
Herrn Professor Dr.-Ing. habil.F. Asinger zum 60. Geburtstag gewidmet.
Auszug aus der PromotionsarbeitH. Horn, Techn. Hochsch. Aachen 1966.
2. Mitt.:F. Huber, H. Horn undH.-J. Haupt, Z. Naturforschg., im Druck. 相似文献
During the reaction of Pb(C2H5)4 and acetic acid in anhydrous toluene at 60, 80 and 100° C the two reactions (1) and (2) proceed as competitive consecutive second order reactions. The reaction was studied by nonaqueous titration of acetic acid with KOCH3-solution. Rate constants and activation energies have been determined.
Mit 9 Abbildungen.
Herrn Professor Dr.-Ing. habil.F. Asinger zum 60. Geburtstag gewidmet.
Auszug aus der PromotionsarbeitH. Horn, Techn. Hochsch. Aachen 1966.
2. Mitt.:F. Huber, H. Horn undH.-J. Haupt, Z. Naturforschg., im Druck. 相似文献
136.
Accurate electric dipole moment functions have been calculated for the stretching vibrational coordinates of the linear molecules HCN, HNC, HCCF and HC3N by means of coupled cluster theory with single and double excitation operators plus a quasi-perturbative treatment of connected triples (CCSD(T)). Combining these with anharmonic stretching vibrational wave-functions absolute IR intensities for strecthing vibrational transitions up to high overtones are obtained. For HCN, excellent agreement with experiment is observed up to 7 ν1 + η3 at 23047 cm−1. HCCF and DCCF show unusual behavior, with the ν2 band with origin at 2239.2 cm−1 being strongest in HCCF and the ν1 band with origin at 2645.1 cm−1 being the most intense in DCCF. The Fermi resonance system 2ν3/ν2 of DCCF is analysed in detail. The calculated IR intensities of the stretching fundamentals of HC3N and DC3N, which are difficult to obtain with high accuracy, are in very good agreement with the existing experimental data. 相似文献
137.
Michael I. Bruce Ernst Horn Omar Bin Shawkataly Michael R. Snow 《Journal of organometallic chemistry》1985,280(2):289-298
Deprotonation (K[HBBu3s]) of HRu3(μ3-C2But)(CO)9, followed by reaction of the anion with [O{Au(PPh3)}3][BF4], afforded the known complex Ru3Au(μ3-C2But)(CO)9 (9%), the vinylidene cluster Ru3Au2(μ3-CCHBut)(CO)9(PPh3)2 (16%) and the hexanuclear Ru3Au3(C2But)(CO)8(PPh3)3 (3%). The X-ray structure of the pentanuclear complex shows an asymmetric trigonal-bipyramidal Ru3Au2 core (Ru, Au at the apices) with the Ru3 face bridged by a t-butylvinylidene ligand, being σ-bonded to Ru(1) and Ru(3), and η2-coordinated to Ru(2). Crystals are monoclinic, space group P21/n with a 19.121(3), b 13.109(3), c 23.649(4) Å, β 106.76(2)° and Z = 4. The structure was solved using 4405 observed diffractometer data, and refined to R 0.044, Rw 0.047. 相似文献
138.
Michael I. Bruce E. Horn M.R. Snow M.L. Williams 《Journal of organometallic chemistry》1984,276(2):c53-c57
Hydrogenation of [Ru3(CO)10(L2)] (L2 = dppm or dpam) affords [HRu3(μ3-PhECH2EPh2)(CO)9] (E = P or As), which is deprotonated by K[HBBu3s] . Reactions of the anions with [PhN2] [PF6] give [Ru3(μ-N2Ph)(μ3-PhECH2EPh2)(CO)9], which undergo facile cyclometallation reactions when heated, as revealed by an X-ray structure of the title complex. 相似文献
139.
H. Nölle A. Horn J. Hüve B. Nölle J. Reinhardt J. Schmand H. J. Andrä E. W. Weber 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1994,30(2):227-229
Cooling and optical pumping by a circularly polarized two mode laser is applied to a Na atomic beam in transverse geometry. The low velocity components of the beam are transversly cooled to the Doppler limit temperature of 240 µK and are simultaneously spin polarized for more than 90%. 相似文献