排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
V. L. Ivanov R. R. Akhmetshin A. N. Amirkhanov A. V. Anisenkov V. M. Aulchenko V. S. Banzarov N. S. Bashtovoy D. E. Berkaev A. V. Bragin S. I. Eidelman D. A. Epifanov L. B. Epshteyn A. L. Erofeev G. V. Fedotovich S. E. Gayazov A. A. Grebenuk D. N. Grigoriev E. M. Gromov F. V. Ignatov S. V. Karpov V. F. Kazanin B. I. Khazin I. A. Koop O. A. Kovalenko A. N. Kozyrev E. A. Kozyrev P. P. Krokovny A. E. Kuzmenko A. S. Kuzmin I. B. Logashenko P. A. Lukin K. Yu. Mikhailov V. S. Okhapkin Yu. N. Pestov E. A. Perevedentsev A. S. Popov G. P. Razuvaev Yu. A. Rogovsky A. L. Romanov A. A. Ruban N. M. Ryskulov A. E. Ryzhenenkov V. E. Shebalin D. N. Shemyakin B. A. Shwartz D. B. Shwartz A. L. Sibidanov Yu. M. Shatunov P. Yu. Shatunov E. P. Solodov V. M. Titov A. A. Talyshev A. I. Vorobiov Yu. V. Yudin 《Physics of Atomic Nuclei》2016,79(2):251-259
We report preliminary results on the cross section of the process e+e? → φ(1020)η measured at 30 center-of-mass energy points in the range from 1.59 up to 2.0 GeV. Data analysis is based on the integrated luminosity of 22 pb?1 collected with the CMD-3 detector in 2011–2012. The obtained cross section agrees with the BaBar measurement and has better statistical accuracy. 相似文献
2.
In this work, first we formulate and compare three different discontinuous Interior Penalty Galerkin methods for the 2D Keller–Segel chemotaxis model. Keller–Segel chemotaxis model is the important starting step in the modeling of the real biological system. We show in the numerical tests that two of the proposed methods fail to give accurate, oscillation-free solutions. 相似文献
3.
V. S. Ryaben’kii V. I. Turchaninov Ye. Yu. Epshteyn 《Computational Mathematics and Mathematical Physics》2006,46(10):1768-1784
An algorithm composition scheme for the numerical solution of boundary value problems in composite domains is proposed and illustrated using an example. The scheme requires neither difference approximations of the boundary conditions nor matching conditions on the boundary between the subdomains. The scheme is suited for multiprocessor computers. 相似文献
4.
A. A. Artamonov V. S. Epshteyn V. B. Gavrilov A. A. Gavrilyuk P. A. Gorbounov A. S. Jokin N. V. Lychkovskaya V. P. Popov G. B. Safronov V. V. Shamanov P. B. Shatalov A. A. Spiridonov I. I. Tsukerman 《Physics of Atomic Nuclei》2016,79(3):433-443
Recent achievements of the ATLAS and CMS experiments at the Large Hadron Collider searching for a Higgs boson are summarized. A new particle with the mass of 125 GeV and properties expected for the Standard Model Higgs boson was discovered three years ago in these experiments in proton-proton collisions when analyzing part of the data taken at the centre-of-mass energies 7 TeV and 8 TeV in 2011 and 2012 year exposures. Today all the data are processed and fully analyzed. Experimental results of studies of individual Higgs boson decay channels as well as their combination to extract such properties as mass, signal strength, coupling constants, spin and parity are reviewed. All experimental results are found to be compatible with the Standard Model predictions. 相似文献
5.
Kumar A Goldberg I Botoshansky M Buchman Y Gross Z 《Journal of the American Chemical Society》2010,132(43):15233-15245
A series of five free-base corroles were metalated and brominated to form 10 manganese(III) corroles. Two of the free-base corroles and six manganese(III) corroles were analyzed by X-ray crystallography, including one complex that may be considered a transition-state analogue of oxygen atom transfer (OAT) from (oxo)manganese(V) to thioansisole. Oxidation by ozone allowed for isolation of the 10 corresponding (oxo)manganese(V) corroles, whose characterization by (1)H and (19)F NMR spectroscopy and electrochemistry revealed a low-spin and triply bound manganese-oxygen moiety. Mechanistic insight was obtained by investigating their reactivity regarding stoichiometric OAT to a series of p-thioanisoles, revealing a magnitude difference on the order of 5 between the β-pyrrole brominated (oxo)manganese(V) corroles relative to the nonbrominated analogues. The main conclusion is that the (oxo)manganese(V) corroles are legitimate OAT agents under conditions where proposed oxidant-coordinated reaction intermediates are irrelevant. Large negative Hammett ρ constants are obtained for the more reactive (oxo)manganese(V) corroles, consistent with expectation for such electrophilic species. The least reactive complexes display very little selectivity to the electron-richness of the sulfides, as well as a non-first-order dependence on the concentration of (oxo)manganese(V) corrole. This suggests that disproportionation of the original (oxo)manganese(V) corrole to (oxo)manganese(IV) and (oxo)manganese(VI) corroles, followed by substrate oxidation by the latter complex, gains importance when the direct OAT process becomes progressively less favorable. 相似文献
6.
The synthesis and solid-state structural characterization of a family of homoleptic and mixed dialkyl d1Ta(IV) complexes of the formula, (eta5-C5Me5)TaR1R2[N(i-Pr)C(Me)N(i-Pr)], where R1 = R2 = i-Bu (3), n-Bu (4), and Et (7), and R1 = Me, R2 = i-Bu (10), neopentyl (Np) (11), are reported, along with those for the cationic d1Ta(IV) complex, {(eta5-C5Me5)TaNp[N(i-Pr)C(Me)N(i-Pr)]}[B(C6F5)4] (12). All of the new compounds displayed a remarkably high degree of solution stability toward beta-hydrogen and beta-methyl eliminations/abstractions. Thermolysis of 3 in toluene at 80 degrees C for 18 h provided the Ta(IV) trimethylenemethane (TMM) complex 13. 相似文献
7.
Andrew P. Purdy Rebecca Sorber Albert Epshteyn Katherine A. Pettigrew Joel B. Miller 《Journal of nanoparticle research》2011,13(10):5435-5448
Hafnium tetrachloride was reduced in organic solvents with lithium powder, sodium–potassium alloy, or lithium hydride/Et3B. All reductions required sonochemical agitation to proceed at an appreciable rate, with the notable exception of the reaction
of HfCl4 with Li in diethyl ether. Activation of C–H bonds occurred in all reactions, which resulted in carbon-containing products.
HfCl4 was reduced on a 50-g scale with LiH/Et3B, and a 10-g scale with Li powder in pentane. All the solid products from the reductions were converted to nanomaterials
by annealing under vacuum from 500 to 1,000 °C, which also resulted in the sublimation of the alkali metal salts. The nanomaterials
contain a mixture of products with the α-Hf (hexagonal) structure (crystallite size 8–250 nm) and the HfC (FCC) structure
(crystallite size 3–80 nm), with the amount of hafnium in the bulk annealed product varying from 88 to 99 wt%. When toluene,
pentane, or triethylamine solvents were used, the presence of amorphous graphitic or carbonaceous material was also detected
by solid state 13C NMR. Thermally annealed products were additionally characterized by electron microscopy and thermal analysis under Ar/O2, and have BET surface areas ranging from 2.7 to 155 m2/g. 相似文献
8.
Alina Chertock Yekaterina Epshteyn Hengrui Hu Alexander Kurganov 《Advances in Computational Mathematics》2018,44(1):327-350
Chemotaxis refers to mechanisms by which cellular motion occurs in response to an external stimulus, usually a chemical one. Chemotaxis phenomenon plays an important role in bacteria/cell aggregation and pattern formation mechanisms, as well as in tumor growth. A common property of all chemotaxis systems is their ability to model a concentration phenomenon that mathematically results in rapid growth of solutions in small neighborhoods of concentration points/curves. The solutions may blow up or may exhibit a very singular, spiky behavior. There is consequently a need for accurate and computationally efficient numerical methods for the chemotaxis models. In this work, we develop and study novel high-order hybrid finite-volume-finite-difference schemes for the Patlak-Keller-Segel chemotaxis system and related models. We demonstrate high-accuracy, stability and computational efficiency of the proposed schemes in a number of numerical examples. 相似文献
9.
Rokhlenko Y Geacintov NE Shafirovich V 《Journal of the American Chemical Society》2012,134(10):4955-4962
The exposure of guanine in the oligonucleotide 5'-d(TCGCT) to one-electron oxidants leads initially to the formation of the guanine radical cation G(?+), its deptotonation product G(-H)(?), and, ultimately, various two- and four-electron oxidation products via pathways that depend on the oxidants and reaction conditions. We utilized single or successive multiple laser pulses (308 nm, 1 Hz rate) to generate the oxidants CO(3)(?-) and SO(4)(?-) (via the photolysis of S(2)O(8)(2-) in aqueous solutions in the presence and absence of bicarbonate, respectively) at concentrations/pulse that were ~20-fold lower than the concentration of 5'-d(TCGCT). Time-resolved absorption spectroscopy measurements following single-pulse excitation show that the G(?+) radical (pK(a) = 3.9) can be observed only at low pH and is hydrated within 3 ms at pH 2.5, thus forming the two-electron oxidation product 8-oxo-7,8-dihydroguanosine (8-oxoG). At neutral pH, and single pulse excitation, the principal reactive intermediate is G(-H)(?), which, at best, reacts only slowly with H(2)O and lives for ~70 ms in the absence of oxidants/other radicals to form base sequence-dependent intrastrand cross-links via the nucleophilic addition of N3-thymidine to C8-guanine (5'-G*CT* and 5'-T*CG*). Alternatively, G(-H)(?) can be oxidized further by reaction with CO(3)(?-), generating the two-electron oxidation products 8-oxoG (C8 addition) and 5-carboxamido-5-formamido-2-iminohydantoin (2Ih, by C5 addition). The four-electron oxidation products, guanidinohydantoin (Gh) and spiroiminodihydantoin (Sp), appear only after a second (or more) laser pulse. The levels of all products, except 8-oxoG, which remains at a low constant value, increase with the number of laser pulses. 相似文献
10.
V. E. Shebalin A. V. Anisenkov V. M. Aulchenko N. S. Bashtovoy D. A. Epifanov L. B. Epshteyn A. A. Grebenuk F. V. Ignatov A. L. Erofeev O. A. Kovalenko A. N. Kozyrev A. S. Kuzmin I. B. Logashenko K. Yu. Mikhailov G. P. Razuvaev A. A. Ruban B. A. Shwartz A. A. Talyshev V. M. Titov Yu. V. Yudin 《Physics of Atomic Nuclei》2015,78(13):1544-1551
The structure of the barrel calorimeter of the CMD-3 detector is presented in this work. The procedure of energy calibration of the calorimeter and the method of photon energy restoration are described. The distinctive feature of this barrel calorimeter is its combined structure; it is composed of two coaxial subsystems: a liquid xenon calorimeter and a crystalline CsI calorimeter. The calorimeter spatial resolution of the photon conversion point is about 2 mm, which corresponds to an angular resolution of ~6 mrad. The energy resolution of the calorimeter is about 8% for photons with energy of 200 MeV and 4% for photons with energy of 1 GeV. 相似文献