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141.
The first results of the television observations of meteors at the Ondejov Observatory are presented. It is shown that three spectral components may be distinguished in meteors: cool meteoric, hot meteoric and hot atmospheric. The intensity ratio of these components varies strongly even in meteors of the same velocity and within the records of single meteors. This is evidence for variations in the ablation process and in the formation of the shock wave. The so called calcium anomaly is in fact only a demonstration of these variations. 相似文献
142.
René Hudec Pavel Spurný Jan Florián Jaroslav Boček Miloš Tichý Jana Tichá Libor Vyskočil Wolfgang Wenzel Scott Barthelmy Thomas Cline Niels Gehrels Gerald Fishman Chryssa Kouveliotou Charles Meegan Asen Mutafov 《Experimental Astronomy》1997,7(4):319-323
We present first preliminary results obtained with the European Observation Network consisting of 9 observatories in the Czech Republic, Germany and Bulgaria. We also discuss related problems such as the background of unknown variable stars and suggest a strategy for work in this area. 相似文献
143.
Matthias Jonas Katharina Fleischmann Andrey V. Ganopolski Jaroslav Krabec Uta Sauer Krzysztof Olendrzyński Vladimir K. Petoukhov Roderick W. Shaw 《Climatic change》1996,34(3-4):479-512
This paper describes a methodology that combines the outputs of (1) the Integrated Model to Assess the Greenhouse Effect (IMAGE Version 1.0) of the Netherlands National Institute of Public Health and Environmental Protection (RIVM) (given a greenhouse gas emission policy, this model can estimate the effects such as global mean surface air temperature change for a wide variety of policies) and (2) ECHAM-1/LSG, the Global Circulation Model (GCM) of the Max-Planck Institute for Meteorology in Hamburg, Germany. The combination enables one to calculate grid point surface air temperature changes for different scenarios with a turnaround time that is much quicker than that for a GCM. The methodology is based upon a geographical pattern of the ratio of grid point temperature change to global mean values during a certain period of the simulation, as calculated by ECHAM-1/LSG for the 1990 Scenarios A and D of the Intergovernmental Panel on Climate Change (IPCC). A procedure, based upon signal-to noise ratios in the outputs, enabled us to estimate where we have confidence in the methodology; this is at about 23% to 83% of the total of 2,048 grid points, depending upon the scenario and the decade in the simulation. It was found that the methodology enabled IMAGE to provide useful estimates of the GCM-predicted grid point temperature changes. These estimates were within 0.5K (0.25K) throughout the 100 years of a given simulation for at least 79% (74%) of the grid points where we are confident in applying the methodology. The temperature ratio pattern from Scenario A enabled IMAGE to provide useful estimates of temperature change within 0.5K (0.25K) in Scenario D for at least 88% (68%) of the grid points where we have confidence; indicating that the methodology is transferable to other scenarios. Tests with the Geophysical Fluid Dynamics Laboratory GCM indicated, however, that a temperature ratio pattern may have to be developed for each GCM. The methodology, using a temperature ratio pattern from the 1990 IPCC Scenario A and involving IMAGE, gave gridded surface air temperature patterns for the 1992 IPCC radiative-forcing Scenarios C and E and the RIVM emission Scenario B; none of these scenarios has been simulated by ECHAM-1/LSG. The simulations reflect the uncertainty range of a future warming.The work reported by the authors was carried out during their stay at the project Forestry and Climate Change of the International Institute for Applied Systems Analysis, Laxenburg, Austria. 相似文献
144.
A New GIS-based Solar Radiation Model and Its Application to Photovoltaic Assessments 总被引:3,自引:0,他引:3
The solar radiation model r.sun is a flexible and efficient tool for the estimation of solar radiation for clear‐sky and overcast atmospheric conditions. In contrast to other models, r.sun considers all relevant input parameters as spatially distributed entities to enable computations for large areas with complex terrain. Conceptually the model is based on equations published in the European Solar Radiation Atlas (ESRA). The r.sun model was applied to estimate the solar potential for photovoltaic systems in Central and Eastern Europe. The overcast radiation was computed from clear‐sky values and a clear‐sky index. The raster map of the clear‐sky index was computed using a multivariate interpolation method to account for terrain effects, with interpolation parameters optimized using a cross‐validation technique. The incorporation of terrain data improved the radiation estimates in terms of the model's predictive error and the spatial pattern of the model outputs. Comparing the results of r.sun with the ESRA database demonstrates that integration of the solar radiation model and the spatial interpolation tools in a GIS can be especially helpful for data at higher resolutions and in regions with a lack of ground measurements. 相似文献
145.
146.
Two experimental techniques have been used for study of mass transfer from a drop of 1-hexanol evaporating into air. In the first technique, liquid is added to the drop by a supporting capillary. When the rate of liquid adding counterbalances the evaporation rate, the drop size remains constant and the evaporation takes place at steady state. In the second case with drop suspended from a thermocouple, the rate of evaporation is determined from variation of drop diameter with time. Since the combination of both methods should allow to measure at the broader range of experimental conditions, the differences and their impact on experimental determination of mass transfer are discussed. The results are compared with results of previous experimental and theoretical works reported in the literature. 相似文献
147.
Summary The dependence of the individual parameters of geomagnetic Pc3 pulsations, of their frequencies, amplitudes, phases, flattening of their polarization ellipses, the orientation of their major axis and the sense of rotation of the disturbance vector, are determined from the records made at the Budkov and Niemegk Observatories. Also their diurnal variations at both stations and the correlation of the numerical values between both stations are given. 相似文献
148.
New trace element analyses have been made on the composite Canadian Precambrian shield samples reported in 1967.The overall mean abundance of Cr has been revised to 35 ppm (from 99). New abundances similar to 1967 values are (in ppm): Ni, 19; Co, 12; Cu, 14; Zr, 300; Sr, 315; Ba, 1070; Rb, 110: individual 1967 Rb values were erroneous.Elements not previously determined have the following overall mean values (in ppm): Zn, 52; Sc, 7.0; Nb, 26; Hf, 6.9; La, 32; Ce, 65; Nd, 26; Sm, 4.5; Eu, 0.94; Gd, 2.8; Tb, 0.48; Ho, 0.62; Yb, 1.5; Lu, 0.23; Y, 21; Pb, 17; values in ppb are: Ir, 0.02; Au, 1.8; Tl, 520.Clear positive correlations among Mg-Cr-Ni-Ir-Au appear for all rock-types, marble and quartzite as well as mafic igneous. Regional differences are apparent for several elements: e.g. higher Au, Ir, Cr, Ni in Baffin Island and Northern Quebec composites, compared with Saskatchewan and Southwestern Quebec; high Ti, Zn, Nb, Zr, Hf, REE, Y, Sr, K/T1 abundances and negative Eu anomalies in Southwestern Quebec.The overall REE abundances (omitting Southwestern Quebec) differ from other surface continental crustal rock estimates. 相似文献
149.
Between pH 3.5 and 7, humic acids form a water-soluble uranyl-humic acid complex with the uranyl ion, UO22+ (log β1 = 7.8 ± 0.4 at μ = 0.1). The stability constant of the complex is practically independent of the ionic strength (μ). Experimental results can be explained by the formation of a complex in which every uranyl ion is simultaneously bonded to one phenolic oxygen and one dissociated carboxyl group. The bonding through the phenolic group is considerably stronger than that through carboxylic groups. 相似文献
150.
nua m¶rt; nma aaua a, umua m nma, m n¶rt;um umau nuau un nmam. m¶rt; annua aaum nauu Pi2 u Pc3 u amu u u ¶rt;. ¶rt;a ma m ¶rt; nmam nuau aamumu u u auum m aum amumu. 相似文献