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61.
S. Bellucci Yu. A. Chesnokov P. N. Chirkov M. Ćosić G. Giannini V. A. Maisheev S. Petrović I. A. Yazynin 《JETP Letters》2014,98(11):649-651
The phenomenon of the deflection of a charged particle beam due to channeling in a bent crystal is thoroughly investigated and successfully applied for the extraction of the beam in high-energy accelerators, at the energies of about 10 GeV and higher. However, a big practical interest lies in the task of bending and extracting charged particles with energies below 1 GeV, for example, for the production of ultrastable beams of low emittance for medical and biological applications. That is why a novel crystal technique, namely thin straight crystal targets, is investigated in this article, using crystals as elements for extraction and collimation of the circulating beam in a ring accelerator. The advantages of reflection in straight crystals in comparison with bent crystal channeling consist in the small length of straight crystals along the beam that reduces the amount of nuclear interactions and improves the background. Experimental results were obtained for the bending of a 100 MeV positron beam with using five sequential straight crystals. 相似文献
62.
New solitary and extended wave solutions of the generalized sinh-Gordon (SHG) equation with a variable coefficient are found by utilizing the self-similar transformation between this equation and the standard SHG equation. Two arbitrary self-similar functions are included in the known solutions of the standard SHG equation, to obtain exact solutions of the generalized SHG equation with a specific variable coefficient. Our results demonstrate that the solitary and extended waves of the variable-coefficient SHG equation can be manipulated and controlled by a proper selection of the two arbitrary self-similar functions. 相似文献
63.
Jerković I Gašo-Sokač D Pavlović H Marijanović Z Gugić M Petrović I Kovač S 《Molecules (Basel, Switzerland)》2012,17(2):2058-2072
GC and MS were used for the analysis of Croatian Centaurium erythraea Rafn essential oil (obtained by hydrodistillation) and headspace (applying headspace solid-phase microextraction). The headspace contained numerous monoterpene hydrocarbons (the major ones were terpinene-4-ol, methone, p-cymene, γ-terpinene and limonene). Oxygenated monoterpenes were present in the headspace and oil, while 1,8-cineole, bornyl acetate and verbenone were present only in the headspace. High headspace percentages of toluene and naphthalene were found, followed by hemimellitene. Lot of similarities were observed with Serbian C. erythraea oil [neophytadiene (1.4%), thymol (2.6%), carvacrol (6.1%) and hexadecanoic acid (5.7%)], but different features were also noted such as the presence of menthol, menthone and phytone. The oil fractionation enabled identification of other minor compounds not found in total oil such as norisoprenoides, alk-1-enes or chromolaenin. The essential oil showed antimicrobial potential on Escherichia coli, Salmonella enteritidis, Staphylococcus aureus and Bacillus cereus. On the other hand, no antibacterial activity of the oil was observed on Pseudomonas fluorescens and Lysteria monocytogenes. 相似文献
64.
Ljubica R. Dja?anin Miroslav D. Drami?anin Svetlana R. Luki?-Petrovi? Dragoslav M. Petrovi? Marko G. Nikoli? 《Central European Journal of Physics》2012,10(2):519-523
Lithium-indium oxide is a high-density (5.9 g·cm−3), wide band-gap semiconductor with promising applications for scintillating detection of solar neutrinos as well as for efficient
phosphorescence when doped with Er3+ or Sm3+ ions. In this report, we demonstrate visible upconversion emission of Er3+-doped LiInO2 synthesized by a simple solid-state chemistry procedure and discuss mechanisms responsible for pumping the Er3+ ions to upper levels. Intense upconversion emission is observed in the green and red spectral regions under near-infrared
excitation, and it is greatly enhanced by co-doping with Yb3+ ions. We also examined the upconversion intensity change as a function of temperature, and, consequently, possible applications
of this material as a low-temperature sensor. 相似文献
65.
Filipović J. Petrović-Đakov D. Katsikas L. Božić B. 《Journal of Thermal Analysis and Calorimetry》2000,62(1):251-256
Copolymers of dimethyl itaconate (DMI) and 4-vinylpyridine (4VP) were synthetized in toluene at 60°C with0.26 mol% of AIBN
as initiator. Their compositions were determined by differential refractometry and by differential scanning calorimetry. The
4VP contents of the copolymer samples ranged between 7 and 75 mol%. The reactivity ratios calculated via the Fineman-Ross
method were r
1=0.24 (DMI) and r
2=0.57 (4VP).
The thermal degradations of these copolymers were studied. The results of thermogravimetric measurements indicated that the
copolymers degrade at lower temperatures than those of their parent homopolymers. A possible explanation of this anomalous
behaviour is the formation of thermally unstable structures during the copolymerisation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
66.
Djaković-Sekulić Tatjana Lj. Perišić-Janjić Nada U. Petrović Slobodan D. 《平面色谱法杂志一现代薄层色谱法》2003,16(2):147-153
JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of para-substituted amides of α-phenylacetic, benzoic, propanoic, and 2,2-dimethylpropanoic acid... 相似文献
67.
The measurement accuracy of different hot-wire probes possessing between two and 12 sensors is analyzed. Experimental data were sampled in a round free jet and in a zero-pressure-gradient turbulent boundary layer by a 12-sensor hot-wire probe. Testing of the various hot-wire configurations is enabled by selectively considering different combinations of the 12 available anemometer output voltages. The influence on the measurement accuracy of neglecting the velocity gradients as well as neglecting one velocity component is analyzed. Two approaches were applied. One is based on expressions that relate the instantaneous velocity components and velocity gradients, and the other is based on a simple least-squares regression method. It is found that neglecting the instantaneous fluctuations of the velocity gradients for the measurement of the cross-stream velocity component, V, has a crucial influence and results in large errors. It is also shown that this influence is less significant or even negligible for the measurement accuracy of the other two velocity components, U and W. 相似文献
68.
Zorica D. Petrović Jelena Đorović Dušica Simijonović Snežana Trifunović Vladimir P. Petrović 《Chemical Papers》2018,72(9):2171-2180
N-Salicylidene and N-vanillidene anil Schiff bases SB-1–5 were evaluated for their iron-coordinating properties. For this purpose, reactions with Fe(III) chloride were performed. The obtained results showed that salicylaldehyde bases SB-1 and SB-2 are the best coordinating ligands among the investigated SBs. The corresponding complexes are obtained in good yield and investigated using UV–Vis spectrophotometry and IR spectroscopy. The inhibitory potential of SB-1–5 against iron-containing enzyme lipoxygenase (LOX) was also tested. Salicylidene bases exerted better activity then vanilliden. The cytotoxic in vitro activities against human breast carcinoma MDA-MB-231 and human colon carcinoma HCT-116 cell lines were determined. Based on these results, SB-1 and SB-2 can be considered as interesting compounds for further in vivo investigations. 相似文献
69.
Summary Dual retention behaviour on cellulose, silica and alumina in thin-layer chromatography, that is, the separation of solutes either in normal phase or in reversed phase mode is discussed as a function of the mobile phase polarity utilizing the solubility parameter theory and then correlated with the molecular structure of the solute. 相似文献
70.
A kinetic method for the determination of microquantities of d(?)-arabinose is presented. The method is based on the accelerating effect of d(?)-arabinose on the reaction between molybdenum(VI) and hydrogen peroxide in solution containing 50 vol% of acetonitrile. In order to find optimum experimental conditions for the determination of d(?)-arabinose, the kinetics of the reaction between molybdenum(VI) and hydrogen peroxide in the presence, as well as in the absence, of d(?)-arabinose was studied. d(?)-Arabinose was determined photometrically by following the rate of the colored reaction product formation. The concentrations of d(?)-arabinose which were determined ranged from 46 to 135 μg/ml, and the standard deviation was lower than 10%. 相似文献