4,185 research outputs found
Poems selected from Karamzin, Pushkin, Tyutchev, Lermontov, Count A. Tolstoy, Nikitin, Pleshcheyev, Nadson, and Sologub.
No full textAdded t.p. in Russian.Eight pages at end, with running title: Dlia zamietok.Poems in Russian, grouped under author; English translations follow each group.--Karamzin. --Pushkin. --Tyutchev. --Lermontov. --Count A. Tolstoy. -- Nikitin. -- Pleshcheyev. --Nadson. --Sologub.Mode of access: Internet
The Khozhenie za tri morya of Afanasy Nikitin: a critical edition
Get PDFThe subject of this thesis is the Khozhenie za tri morya, an account of a journey to India by a 15th century Russian merchant, Afanasy Nikitin, of his sojourn there and of his return thence. After a brief introduction the author examines the history of this document both with regard to early copies of the text and to more recent attitudes towards the work. The second section consists of a translation into English of the fullest version of the text which has been obtained by taking the fullest extant copy and adding to it various words, phrases and passages which only occur in other versions. The third section of the work consists of commentary notes on the translation with particular emphasis on the vocabulary used by Nikitin and on points of general interest. In the fourth section, "Notes on the Historical and Geographical Background to the Khozhenie", the author examines the history of the various regions through which Nikitin passed, thereby building up a picture of the conditions which he encountered. There are notes on the location and character of the various towns through which he passed. The next section, "Russian Awareness of India before Nikitin", examines the question of how much was known of India in medieval Russia. The author makes the point that it was not an entirely unknown land and that certain connections had existed between the two countries prior to Nikitin's visit. In the sixth section, "Nikitin - a Traveller among Travellers", Nikitin's work is contrasted with the works of other travellers to the East who had preceded him. It is pointed out that, whilst his account is perhaps less important than some Russian commentators maintain, it is worthy of more consideration than it has generally been granted in the West. A reference section, bibliography and glossary complete the original work in this thesis. Copies of several versions of the text are included in the appendices, as is a map showing Nikitin's route
A Novel Approach for Investigation of Chain Transfer Events by Pulsed Laser Polymerization
No full textPulsed laser polymerization (PLP) with subsequent analysis of molecular mass distribution (MMD) is used to determine the rate coefficient of chain transfer to an agent A, k(trA), by varying pulse repetition rate such that the contributions of PLP-induced and chain-transfer-induced peaks to the MMD change to a significant extent. It is shown by simulation that the relative heights of these peaks may be used to estimate k(trA). The method is applied to evaluation of the rate coefficient of chain transfer to dodecylmercaptan with butyl methacrylate polymerizations at -11, 0, 20 and 40 degrees C. The Arrhenius parameters for this coefficient are determined to be: A(k(trA)) (2.2 +/- 0.6) x 10 6 L.mol(-1).s(-1) and E(a)(k(trA)) (22.1 +/- 0.7) kJ.mol(-1)
First observation of the decay Bs0→K*0K*0
Get PDFThe first observation of the decay B0s→K∗0K∗0 is reported using 35 pb−1 of data collected by LHCb in proton–proton collisions at a centre-of-mass energy of 7 TeV. A total of 49.8±7.5 B0s→(K+π−)(K−π+) events are observed within ±50 MeV/c2 of the B0s mass and 746 MeV/c2 < mKπ < 1046 MeV/c2, mostly coming from a resonant B0s→K∗0K∗0 signal. The branching fraction and the CP-averaged K∗0 longitudinal polarization fraction are measured to be B(B0s→K∗0K∗0)=(2.81±0.46(stat.)±0.45(syst.)±0.34(fs/ fd))×10−5 and fL =0.31±0.12(stat.)±0.04(syst.)
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
Get PDFThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
Devonian spores of Kryshtofovichia africani Nikitin (Tracheophyta): morphology and ultrastructure
No full textThe morphology and ultrastructure of spores of the Devonian plant Kryshtofovichia africani Nikitin are examined. The structure of ultrathin exine megaspores of K. africani is established. The exine consists of two layers: granular ectexine and lamellate endexine. Microspores have a lamellate ultrastructure with a trend toward loosening and formation of the granular structure towards the ectexine outer part. Heterospory of K. africani is apparent in both morphological characters and sporoderm ultrastructure of micro- and megaspores.</p
Determination of intramolecular chain transfer and midchain radical propagation rate coefficients for butyl acrylate by pulsed laser polymerization
No full textA novel method to extract individual free-radical polymerization rate coefficients for butyl acrylate intramolecular chain transfer (backbiting), k(bb), and for monomer addition to the resulting midchain radical, k(p)(t), is presented. The approach for measuring k(bb) does not require knowledge of any other rate coefficient. Only the dispersion parameter of SEC broadening has to be determined by fitting measured MWDs or should be available from separate experiments. The method is based upon analysis of the shift in the position of the inflection point of polymer molecular weight distributions produced by a series of pulsed-laser polymerization (PLP) experiments with varying laser pulse repetition rate. The coefficient k(bb) is determined from the onset of the sharp decrease of the apparent propagation rate coefficient (k(p)(app)) with decreasing repetition rate, an approach verified by simulation. With experiments performed between -10 and +30 degrees C, the estimated values are fitted well by an Arrhenius relation with pre-exponential factor A(k(bb)) = (4.84 +/- 0.29) x 10(7) s(-1) and activation energy E-a(k(bb)) = (31.7 +/- 2.5) kJ center dot mol(-1). At low pulse repetition rates, the experimental k(p)(app) values are related to an averaged propagation rate coefficient, k(p)(av), that is dependent on the relative population of chain-end and midchain radicals. Evaluated by comparing simulated and experimental molecular weight distributions, k(p)(av) provides an estimate for k(p)(t). The Arrhenius parameters are: A(k(p)(t)) = (1.52 +/- 0.14) x 10(6) L center dot mol(-1)center dot s(-1) and E-a(k(p)(t)) = (28.9 +/- 3.2) kJ center dot mol(-1)
Measurement of CP asymmetry in D-0 -> K- K+ and D-0 -> pi(-) pi(+) decays
Get PDFTime-integrated CP asymmetries in D 0 decays to the final states K - K + and π - π + are measured using proton-proton collisions corresponding to 3fb-1 of integrated luminosity collected at centre-of-mass energies of 7 TeV and 8 TeV. The D 0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in CP asymmetries between the two final states is measured to be Δ ACP = ACP (K- K +) ACP (π- π+) = (+ 0.14 ± 0.16 (stat) ± 0.08 (syst)) %. A measurement of A CP (K - K +) is obtained assuming negligible CP violation in charm mixing and in Cabibbo-favoured D decays. It is found to be ACP (K- K+) = (- 0.06 ± 0.15 (stat) ± 0.10 (syst)) %, where the correlation coefficient between ΔA CP and A CP (K - K +) is ρ = 0.28. By combining these results, the CP asymmetry in the D 0 → π - π + channel is A CP (π - π +) = (-0.20 ± 0.19 (stat) ± 0.10 (syst))%. [Figure not available: see fulltext.] © 2014 The Author(s)
Free-radical propagation rate coefficients via n-pulse periodic polymerization
No full textAspects of applying n-pulse periodic initiation in pulsed laser polymerization/size exclusion chromatography (PLP/SEC) experiments are studied via simulation of molecular weight distributions (MWDs). IN n-pulse periodic PLP/SEC, sequences of n laser pulses at successive time intervals Deltat(1), up to Deltat(n) are periodically applied. With the dark time intervals being suitably chosen, n-modal MWDs with n well separated peaks occur. The n-pulse periodic PLP/SEC method has the potential for providing accurate propagation rate coefficients, k(p). Among several measures for k(p), the differences in molecular weights at the MWD peak positions yield the best estimate of k(p) under conditions for medium and high pulse laser-induced free-radical concentration. Deducting k(p) from n dark time intervals (corresponding to n regions of free-radical chain length) within one experiment at otherwise identical PLP/SEC conditions allows addressing in more detail a potential chain-length dependence of k(p). Simulations are compared with experimental data for 2-pulse periodic polymerization of methylmethacrylate
Physics demonstrations for upper secondary school students - a video study
Get PDFNázev práce: Fyzikální pokusy pro střední školy - videostudie Autor: Bc. Alexandr Nikitin Katedra / Ústav: Katedra didaktiky fyziky Vedoucí diplomové práce: RNDr. Marie Snětinová, Ph.D., Katedra didaktiky fyziky Abstrakt: Experiment je základním prvkem nejen ve fyzice jako vědě, ale také ve výuce fyziky. Přestože je poslední dobou více pozornosti věnováno samostatnému experimentování žáků, významnou roli ve školách stále hraje demonstrační experiment. Na katedře didaktiky fyziky MFF UK má projekt předvádění demonstračních experimentů pro studenty středních škol tradici více než 30 let a v současné době nabízí celkem sedm tematických celků. Předchozí výzkum provedený na vzorku cca 5100 studentů však ukázal, že tyto tematické celky jsou studenty vnímány poměrně odlišně zejména z hlediska jejich zájmu, vnitřní motivace a subjektivně vnímané užitečnosti a hodnoty. Nabízí se tedy otázka, zda existují parametry, které předurčují pozitivní vnímání demonstračních pokusů studenty - ať už by mělo jít o požadavky na lektora, o způsob práce s publikem či o výběr jednotlivých experimentů. Cílem této práce je představit videostudii zabývající se analýzou těchto vystoupení, jejíž výsledky poslouží k hledání předestřených parametrů. V práci je popsána metodologie tvorby kategoriálního systému užitého ve videostudii,...Title: Physics demonstrations for upper secondary school students - video study Author: Bc. Alexandr Nikitin Department: Department of Physics Education Supervisor: RNDr. Marie Snětinová, Ph.D., Department of Physics Education Abstract: Experiment is a key element not only for physics as science, but also for physics education. Even though attention has been lately focused more on students' hands-on experiments, demonstration experiments still play an important role in today's education. Department of Physics Education (Charles University, Faculty of Mathematics and Physics) has been performing physics demonstrations for upper secondary school students for more than 30 years. Seven different topics are currently offered by the Department. A survey conducted on a population of est. 5,100 students showed that the perception of these topics by students varies quite significantly, especially considering their intrinsic motivation and subjectively perceived value and usefulness of a given topic. The questions at hand are whether parameters that influence students' perception in negative or positive way do exist and how they are related to the choice of the experiments themselves or the lecturer's work with the audience. Aim of this thesis is to present a video study conducted on video recordings of all seven...Department of Physics EducationKatedra didaktiky fyzikyMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
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