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991.
A.A. Kokhanovsky B. Mayer K. Wapler U. Schumann 《Journal of Quantitative Spectroscopy & Radiative Transfer》2007,103(3):460-477
The paper is devoted to theoretical studies of the influence of cloud inhomogeneities on cloud top height (CTH) retrievals based on top-of-atmosphere nadir reflectance observations in the oxygen A-band. A three-demensional (3D) Monte Carlo code is used to simulate highly resolved spectral measurements in the oxygen A-band. These synthetic radiances are used as input for the retrieval code SACURA based on asymptotic radiative transfer theory and the independent pixel approximation. The results show that the effect of cloud inhomogeneity on the derived CTHs is small. While we found considerable 3D effects in the reflectance of more than 30% compared to the independent column approximation, the spectral dependence of the difference was small. As SACURA is mainly based on spectral ratios, the retrieval results are hardly affected by the large absolute deviations. In consequence, SACURA is capable to retrieve CTHs with an accuracy of better than 1.5 km for overcast and also most partially cloudy cases. 相似文献
992.
993.
Fiber Bragg Grating Writing by Interferometric or Phase-Mask Methods Using High-Power Excimer Lasers
This paper reports the development of high-power excimer lasers with enhanced spatial and temporal coherence. These excimer lasers are applicable to writing fiber Bragg gratings by interferometric or phase-mask techniques. An excimer laser with a novel unstable resonator is analyzed with respect to its suitability to the production of passive fiber-optic components and in terms of production flexibility, efficiency, and reliability. A survey of applicability of this tool to short-and long-period fiber Bragg gratings is presented. 相似文献
994.
995.
Edison discovered that the coefficient of friction between a metallic plate and a porous material moistened with a dilute
electrolyte could be modulated by an electric field. In experiments on the same kind of contacts (clays or chalks on carbon
or metals) but without continuous tangential relative motion we measure two electro-mechanical effects at frequencies of the
order of 10 kHz. An alternating field induces an alternating normal force between the porous material and the conducting base.
The force is lagging by
versus the field. A forced normal relative motion induces through the contact a current nearly in phase with the motion. For an
explanation we start from Helmholtz theory of stationary electrophoretic phenomena. We present a model in which liquid motions
obey the Helmholtz laws. It explains decently the phase relations between causes and effects, and approximately the values
of the effects. In optical experiments on contacts between a wet clay and the transparent conducting coating of a glass plate
we measure in the frequency range 1-100 kHz a modulation of reflecting power induced by an alternating potential. The decrease
of reflecting power is lagging by an angle close to behind the field. We think the modulation observed is induced by a modulation of the amount of liquid in the film present
between glass and clay. In friction experiments this alternating liquid lubrication acting exclusively at the very places
where friction occurs may have significant effect.
Received: 22 July 1997 / Revised: 21 October 1997 / Accepted: 21 November 1997 相似文献
996.
M. Hvecker A. Knop-Gericke H. Bluhm E. Kleimenov R. W. Mayer M. Fait R. Schlgl 《Applied Surface Science》2004,230(1-4):272-282
The surface of an activated vanadium phosphorus oxide (VPO) catalyst was investigated by means of in situ X-ray absorption spectroscopy in the total electron yield mode. We observed significant changes of the V L3-near edge X-ray absorption fine structure (NEXAFS) when the material was transferred from room temperature to working conditions at 400 °C in the reaction atmosphere. We studied the same VPO material under different gas compositions comprising the reaction mixture of n-butane and oxygen, pure oxygen and vacuum to elucidate the influence of the gas–surface interaction and the effect of the temperature. The results of this extensive study indicate a dynamic response of the catalyst surface to the applied conditions. 相似文献
997.
This article presents an approach to the modeling of CaCO3 fouling and cleaning in a microscale cross-flow heat exchanger. The fouling progress was detected by thermal, fluid dynamical, and optical measures. In general, the observed fouling phenomena at microscale were comparable to those at macroscale. The detected thermal fouling resistance was between 10? 6 and 10? 3 m? 2 K? 1. As expected, crystallization fouling strongly depends on the surface temperature. In addition, the surface coverage can be a useful measure for both processes—fouling and cleaning. An extended approach to derive a reasonable fouling allowance was formulated through a fractional fouling resistance. 相似文献
998.
Thomas M. Klapötke Peter Mayer Jörg Stierstorfer 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):2393-2407
Bis(1-aminoguanidinium) sulfate monohydrate (AG2SO4 … H2O, 1), bis(1,3-diamino-guanidinium sulfate (DAG2SO4, 2), bis(1,3,5-triaminoguanidinium) sulfate dihydrate (TAG2SO4 … 2 H2O, 3) and bis(azidoformamidinium) sulfate (AF2SO4, 5) were synthesized and characterized by multinuclear NMR, IR, and Raman spectroscopy and elemental analysis. In the synthesis of 3, double protonated triaminoguanidinium sulfate (HTAGSO4, 4) was obtained as a byproduct. The molecular structures of 1–5 in the crystalline state were determined by low-temperature single crystal X-ray diffraction. 1: orthorhombic, Pnma, a = 6.7222 (8) Å, b = 14.153 (2) Å, c = 11.637 (1) Å, V = 1107.1(2) Å3, Z = 4, ρcalc.= 1.586 g cm?3 R1 = 0.0442, wR2 = 0.1007 (all data). 2: hexagonal, P6122, a,b = 6.6907 (1) Å, c = 43.4600 (8) Å, γ= 120°, V = 1684.86 (5) Å3, Z = 6, ρcalc.= 1.634 g cm?3, R1 = 0.0321, wR2 = 0.0714 (all data). 3: monoclinic, C2/c, a = 9.6174 (8) Å, b = 22.858 (1) Å, c = 6.7746 (5) Å, β= 109.49 (1), V = 1404.0 (4) Å3, Z = 4, ρcalc.= 1.620 g cm?3, R1 = 0.0292, wR2 = 0.0781 (all data). 4: monoclini c, P21/c, a = 8.9998 (9), b = 6.3953 (6), c = 13.3148(12) Å, β= 99.679 (8), V = 755.44 (13) Å3, Z = 4, ρcalc.= 1.778 g cm?3, R1 = 0.0305, wR2 = 0.0809 (all data); 5: orthorhombic, Pbca, a = 11.3855 (9), b = 7.1032 (6), c = 12.807 (1) Å, V = 1035.74 (14) Å3, Z = 4, ρcalc.= 1.720 g cm?3, R1 = 0.0389, wR2 = 0.0862 (all data). 相似文献
999.
We study aspects of the analytic foundations of integration and closely related problems for functions of infinitely many variables x1,x2,…∈D. The setting is based on a reproducing kernel k for functions on D, a family of non-negative weights γu, where u varies over all finite subsets of N, and a probability measure ρ on D. We consider the weighted superposition K=∑uγuku of finite tensor products ku of k. Under mild assumptions we show that K is a reproducing kernel on a properly chosen domain in the sequence space DN, and that the reproducing kernel Hilbert space H(K) is the orthogonal sum of the spaces H(γuku). Integration on H(K) can be defined in two ways, via a canonical representer or with respect to the product measure ρN on DN. We relate both approaches and provide sufficient conditions for the two approaches to coincide. 相似文献
1000.
Aitala EM Amato S Anjos JC Appel JA Ashery D Banerjee S Bediaga I Blaylock G Bracker SB Burchat PR Burnstein RA Carter T Carvalho HS Copty NK Costa I Cremaldi LM Darling C Denisenko K Fernandez A Gagnon P Gerzon S Gobel C Gounder K Halling AM Herrera G Hurvits G James C Kasper PA Kwan S Langs DC Leslie J Lundberg B MayTal-Beck S Meadows B de Mello Neto JR Milburn RH de Miranda JM Napier A Nguyen A d'Oliveira AB O'Shaughnessy K Peng KC Perera LP Purohit MV Quinn B Radeztsky S Rafatian A 《Physical review letters》1996,77(12):2384-2387