排序方式: 共有41条查询结果,搜索用时 15 毫秒
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E. M. Zaytseva R. D. Govorun G. V. Mitsin A. G. Molokanov 《Physics of Particles and Nuclei Letters》2011,8(6):599-605
The effectiveness of the impact of therapeutic proton beams in human cells with respect to the criterion of formation of chromosome
aberrations in human-blood lymphocytes is estimated. The physical characteristics of radiation (proton LET at the input of
the object and in the region of the modified Bragg peak) and the role of the biological factor (the differences in the radiosensitivity
of nondividing cells corresponding to the irradiation of normal tissues along the proton-beam path and tumor tissues) are
taken into account. The relative biological effectiveness of protons is ∼1 at the beam input of the object and ∼1.2 in the
Bragg peak region. Taking into account the higher radiosensitivity of dividing cells in the G
2 phase of the cell cycle, the irradiation effectiveness increases to ∼1.4. 相似文献
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The Advanced Photon Source (APS) at Argonne National Laboratory is considering the development of a superconducting linac-based fourth-generation hard X-ray source to meet future scientific needs of the hard X-ray user community. This work specifically focuses on the design of an optimized 5-cell superconducting radio-frequency structure well suited for a high-energy, high-beam-current energy recovery linac. The cavity design parameters are based on the APS storage ring nominal 7 GeV and 100 mA beam operation. A high-current 5-cell cw superconducting cavity operating at 1.4 GHz has been designed. In order to achieve a high current, the accelerating cavity shape has been optimized and large end-cell beam pipes have been adopted. The beam break-up threshold of the cavity has been estimated using the code TDBBU, which predicts a high threshold beam current for a 7 GeV energy recovery linac model. A copper prototype cavity has been fabricated that uses half-cell modules, initially assembled by clamping the cells together. 相似文献
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Fluoropolymer blends have been widely used as binders for exterior coatings because of their excellent resistance to ultra-violet (UV) radiation as well as to many corrosive chemical agents.It is known that the fluorinated component usually has a lower glass transition temperature and easily crystallizes in the final structure depending upon the blend composition and sample annealing condition.We investigated the effect of blend composition and annealing process (slow and fast cooling) on the surface mor... 相似文献
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Hossein Shirani IL Beigi 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(9):1537-1541
DFT calculations are applied for some stable C60, C59Si, and C59N hetero fullerenes. Sn and Ge atoms are doped at the same position of C60. Computations are carried out at the B3LYP/cc pVDZ levels. In this work the effects of the heteroatoms, Si and N, on the structural properties of the fullerene have been studied. The structure, energetic and relative stabilities of the compounds were compared and analyzed with each other. In addition, vibrations spectra of proposed stable neutral species, as well as the infrared intensities are calculated. From the data obtained from calculation, we found that there is strong correlation between the stability of pure C60 fullerene molecule and the numbers of different C-C bonds. 相似文献
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Ki-Min Park Yongri Jin Joobeom Seo IL Yoon Sang Cheol Lee 《Supramolecular chemistry》2013,25(1):51-58
Novel S4O n mixed donor macrocycles (1, n=1; 2, n=2) were synthesized by the coupling reactions of corresponding dichlorides with dithiols under high dilution conditions. Synthesis and crystal structures of Tl+ and Ag+ complexes, [Tl(2)+ and Ag(2)+], with macrocycle 2 are described. The electrode based on macrocycle 2 showed excellent potentiometric sensing ability for Tl+ and Ag+ ions. This remarkable sensing of the proposed electrode can be understood in terms of the synergy effect of a soft–soft acid–base interaction and π-coordination, especially for the Tl+ ion, which was observed from the crystal structure of the corresponding complex. 相似文献
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N. A. Bonch-Osmolovskaya J. Vrzal J. Lipták N. G. Zaytseva V. G. Tishin J. Urbanec E. P. Grigoriev 《Czechoslovak Journal of Physics》1969,19(2):254-272
The spectrum of -radiation of the radioactive isotope170Lu was studied by means of two Ge(Li) coaxial semiconductor detectors. Around 150-transitions belonging to the decay of170Lu were found and their relative intensities were determined. Using the relative intensities of the conversional electrons from other works the internal conversional coefficients and the multipolarities of -ray transitions in the170Yb nucleus were established. Twenty new excited levels of the170Yb nucleus were introduced.A comparison of the experimental results with the predictions of the superfluid and Davydov models is made. The possible existence of I=O– excited states in the level scheme of170Yb is discussed.
On leave fromFaculty of Mathematics and Physics, Charles University, Behová 7, Praha, Czechoslovakia.
On leave fromNuclear Research Institute, Czechosl. Acad, Sci., e, Czechoslovakia. 相似文献
On leave fromFaculty of Mathematics and Physics, Charles University, Behová 7, Praha, Czechoslovakia.
On leave fromNuclear Research Institute, Czechosl. Acad, Sci., e, Czechoslovakia. 相似文献
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N. N. Kolobylina E. A. Greshnikov A. L. Vasiliev E. Yu. Tereschenko I. E. Zaytseva N. A. Makarov P. K. Kashkarov E. B. Yatsishina M. V. Kovalchuk 《Crystallography Reports》2017,62(4):529-536
The phase compositions of the basic material (alloy) of a pre-Mongolian Old Russian encolpion cross found near Suzdal and its black inlay have been investigated by methods of scanning and transmission electron microscopy and energy-dispersive X-ray microanalysis. The cross material is lead–zinc–tin α-bronze, and the black is copper sulfide with lead inclusions. As a result of the corrosion, tin and copper oxides and zinc sulfides, which made the cross dark gray, were formed on its surface. It is shown that the corrosion depth is as large as 50 μm; thus, laps must be prepared to accurately determine the morphology and phase composition of the corrosion layer. Decoration with black was apparently performed by pouring with copper sulfide melt or melting a powder preliminarily placed in grooves forming an image on the surface. 相似文献