排序方式: 共有14条查询结果,搜索用时 15 毫秒
1.
G.S. Duesberg J. Muster V. Krstic M. Burghard S. Roth 《Applied Physics A: Materials Science & Processing》1998,67(1):117-119
Received: 18 May 1998/Accepted: 22 May 1998 相似文献
2.
It is shown that if is an integral domain which is not a field, and is the subgroup of generated by all unipotent elements, then the quotient group has a free quotient of infinite rank.
3.
Let G be a group, and let Fn[G] be the free G-group of rankn. Then Fn[G] is just the natural non-abelian analogue of thefree ZG-module of rank n, and correspondingly the group n(G)of equivariant automorphisms of Fn[G] is a natural analogueof the general linear group GLn(ZG). The groups n(G) have beenstudied recently in [4, 8, 5]. In particular, in [5] it wasshown that if G is not finitely presentable (f.p.) then neitheris n(G), and conversely, that n(G) is f.p. if G is f.p. andn2. It is a common phenomenon that for small ranks the automorphismgroups of free objects may behave unstably (see the survey article[2]), and the main aim of the present paper is to show thatthis turns out to be the case for the groups 2(G). 相似文献
4.
Dragana Krstic Zoran Jovanovic Vladimir Markovic Dragoslav Nikezic Vlade Urosevic 《Central European Journal of Physics》2014,12(10):714-718
The Boron Neutron Capture Therapy (BNCT) is based on selective uptake of boron in tumour tissue compared to the surrounding normal tissue. Infusion of compounds with boron is followed by irradiation with neutrons. Neutron capture on 10B, which gives rise to an alpha particle and recoiled 7Li ion, enables the therapeutic dose to be delivered to tumour tissue while healthy tissue can be spared. Here, therapeutic abilities of BNCT were studied for possible treatment of liver cancer using thermal and epithermal neutron beam. For neutron transport MCNP software was used and doses in organs of interest in ORNL phantom were evaluated. Phantom organs were filled with voxels in order to obtain depth-dose distributions in them. The result suggests that BNCT using an epithermal neutron beam could be applied for liver cancer treatment. 相似文献
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6.
Cylindrical diffusion chamber for radon measurement equipped with nuclear track detector (CR-39) and electretis considered in this work. Electret is electrostatic analogous of permanent magnet which preserves constant and strong electric
field for long time period. Electrets were used to attract radon progeny formed in a cup where CR-39 was placed for radon
measurements. In this way the sensitivity of detector could be increased by bringing progeny just in front of detector in
more convenient measuring geometry.
Influence of distance between electret and detector on sensitivity of such equipment has been investigated theoretically.
Different geometrical setups of detector and electret were tested in order to optimize this kind of device. Some results are
presented in this report.
相似文献
7.
Due to the increasing frequency of wildfires in recent years, there is a strong need for developing mitigation strategies to manage the impact of smoke exposure of vines and occurrence of ‘smoke taint’ in wine. One plausible approach would be to prevent or inhibit the uptake of volatile phenols from smoke into grape berries in the vineyard. In this study we describe a model system we developed for evaluating under controlled conditions the effectiveness of a range of surface coatings (including existing horticultural sprays) for reducing/preventing the uptake of volatile phenols and their subsequent conversion to phenolic glycosides. Grapes were coated with the materials to be tested and then exposed to gaseous phenols, via evaporation from an aqueous solution, in a semi-closed glass container. Analysis of volatile phenols and their glycosidic grape metabolites demonstrated that the treatments typically did not provide any significant protection; in fact, some resulted in higher concentrations of these compounds in the grapes. The highest concentrations of volatile phenols and their glycosides were observed after application of oily, hydrophobic materials, suggesting that these materials may enhance the adsorption or transfer of volatile phenols into grape berries. Therefore, it is important to consider the types of sprays that are being applied in the vineyard before and during smoke events to prevent the potential of exacerbating the uptake of smoke compounds by grape berries. 相似文献
8.
Milena Zivkovic Nenad Zlatic Tijana Zeremski Milan Stankovic Vesna Manic Dragana Krstic Dragoslav Nikezic 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(3):1285-1298
Journal of Radioanalytical and Nuclear Chemistry - Vertical distribution of natural radionuclides, 137Cs and heavy metals were measured in soil and plants collected from Kragujevac surroundings.... 相似文献
9.
V. D. Krstic 《Theoretical and Applied Fracture Mechanics》1988,10(3):241-247
The effect of pore size and pore volume fraction on strength in brittle solids is evaluated. The analysis considers that the strength degradaton of a solid containing a large number of spherical pores is due to a strong effect of porosity on Young's modulus. Each pore is assumed to possess radial or annular flaws emanating from the pore surface whose lengths are considered to be independent of pore size. The effect of stress concentration induced by the presence of the pore is included in the equation for strength through the Young's modulus dependence of porosity originally developed using the concept of crack opening displacement. It is shown that the strength of a solid containing spherical pores is controlled by the pore size, pore volume fracton and the radial (or annular) crack size to pore size ratio. Predicted variation of strength with pore volume fraction is tested against experimental data for glass and polycrystalline alumina. 相似文献
10.