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排序方式: 共有122条查询结果,搜索用时 15 毫秒
1.
S. Leskinen J. K. Miettinen T. Jaakkola 《Journal of Radioanalytical and Nuclear Chemistry》1987,115(2):289-298
Concentrations of239,240Pu and241Am in filtered seawater, particulate fraction and sediment were measured. Methods for determination of these nuclides were critically chequed and a new rapid method for241Am in sediment was developed. Due to seasonal variation a significant decrease of plutonium and americium concentrations in surface water takes place in summer. Americium is more efficiently associated with particulate matter than plutonium. From May 1980 to September 1984 soluble plutonium in the water was reduced to about half. The residence half-time of239,240Pu in the water of Baltic Sea is of the order of 5 years. About similar concentrations of239,240Pu and241Am were found in particulates in water as in the surface layer of the sediment. The average Kd-values for plutonium and americium were 105 and 105–106 ml/g, respectively. 相似文献
2.
Hydrophobins are small fungal proteins, which have remarkable surface-chemical properties. They self-assemble at hydrophobic/hydrophilic interfaces and work as adhesive agents and coatings. Sixteen layer Langmuir-Blodgett films of hydrophobins HFBI and HFBII from the fungus Trichoderma reesei were prepared and studied using grazing-incidence X-ray diffraction and reflectivity techniques. Both kind of films contain hexagonally ordered crystallites on the substrate with unit cell parameters of a = b = 54 Å (HFBI) and a = b = 55 Å (HFBII). The structure is similar to the structure of monolayer Langmuir-Blodgett films. 相似文献
3.
Anders Lindfors Anu Heikkilä Jussi Kaurola Tapani Koskela Kaisa Lakkala 《Photochemistry and photobiology》2009,85(5):1233-1239
UV radiation exerts several effects concerning life on Earth, and spectral information on the prevailing UV radiation conditions is needed in order to study each of these effects. In this paper, we present a method for reconstruction of solar spectral UV irradiances at the Earth's surface. The method, which is a further development of an earlier published method for reconstruction of erythemally weighted UV, relies on radiative transfer simulations, and takes as input (1) the effective cloud optical depth as inferred from pyranometer measurements of global radiation (300–3000 nm); (2) the total ozone column; (3) the surface albedo as estimated from measurements of snow depth; (4) the total water vapor column; and (5) the altitude of the location. Reconstructed daily cumulative spectral irradiances at Jokioinen and Sodankylä in Finland are, in general, in good agreement with measurements. The mean percentage difference, for instance, is mostly within ±8%, and the root mean square of the percentage difference is around 10% or below for wavelengths over 310 nm and daily minimum solar zenith angles (SZA) less than 70°. In this study, we used pseudospherical radiative transfer simulations, which were shown to improve the performance of our method under large SZA (low Sun). 相似文献
4.
Bonner BE Buchanan JA Clement JM Corcoran MD Krishna NM Kruk JW Lincoln DW Miettinen HE Mutchler GS Nessi-Tedaldi F Nessi M Phillips GC Roberts JB Stevenson PM Tonse SR White JL Chung SU Etkin A Fernow RC Protopopescu SD Willutzki H Hallman T Madansky L Pinsky LS 《Physical review letters》1989,62(14):1591-1594
5.
Bonner BE Buchanan JA Clement JM Corcoran MD Krishna NM Kruk JW Miettinen HE Moss RM Mutchler GS Nessi-Tedaldi F Nessi M Phillips GC Roberts JB Stevenson PM Tonse SR Birman A Chung SU Etkin A Fernow RC Kirk H Protopopescu SD Willutzki H Hallman T Madansky L Bar-Yam Z Dowd J Kern W King E Mayes BW Pinsky LS 《Physical review D: Particles and fields》1990,41(1):13-16
6.
The use of a TDI camera is restricted to cases of viewing from the direction of the surface normal. Our previous work indicated that a TDI camera can be used with viewing angles up to 30° from the surface normal which extends the usability of TDI for visual inspection applications. The objective of this paper is to examine the use of a TDI camera at a non-zero viewing angle under vibration conditions. The effects caused by vibration of the surface to be viewed become critical when using a TDI camera at non-zero viewing angles. A method of approximating the TDI performance under vibration conditions was determined and evaluated experimentally. The resulting measurements support the approximating method developed here. 相似文献
7.
Kaisa Matomäki 《Monatshefte für Mathematik》2008,155(2):167-189
Let 1/5 < θ ≤ 1. We prove that there exists a positive constant δ such that the number of even integers in the interval [X, X + X
θ] which are not a sum of two primes is 《 X
θ−δ. The proof uses the circle method, a sieve method, exponential sum estimates and zero-density estimates for L-functions.
Current address: Department of Mathematics, 20014 University of Turku, Finland.
Author’s address: Department of Mathematics, University of London, Royal Holloway, Egham, Surrey TW20 0EX, UK 相似文献
8.
9.
We analyze the absorption structure of diffractive dissociation discussing simultaneously the elastic and inelastic processes. This approach is motivated by their close interdependence and mutual influence. We show that the results differ significantly from the standard picture of elastic scattering. In particular, protons are shown to have very rich internal structure coupling both to “black” and “transparent” diffractive scattering eigenstates. Proton matter distribution may well be very different from that suggested by the analysis of Chou and Yang. Finally, the indicated asymptotic behaviour is that of a “grey” instead of a “black” disc limit. 相似文献
10.