1,484 research outputs found
Adatom incorporation and step crossing at the edges of 2D nanoislands
Adatom incorporation into the ``faceted'' steps bordering the 2D nanoislands
is analyzed. The step permeability and incorporation coefficients are derived
for some typical growth situations. It is shown that the step consisting of
equivalent straight segments can be permeable even in the case of fast egde
migration if there exist factors delaying creation of new kinks. The step
consisting of alternating rough and straight segments may be permeable if there
is no adatom transport between neighboring segments through the corner
diffusion.Comment: 3 pages, one figur
Spurious trend switching phenomena in financial markets
The observation of power laws in the time to extrema of volatility, volume
and intertrade times, from milliseconds to years, are shown to result
straightforwardly from the selection of biased statistical subsets of
realizations in otherwise featureless processes such as random walks. The bias
stems from the selection of price peaks that imposes a condition on the
statistics of price change and of trade volumes that skew their distributions.
For the intertrade times, the extrema and power laws results from the format of
transaction data
Investigation of preparative possibilities of iodinating systems on the basis of N-iodoacetamide
N-iodoacetamide in organic solvents with H2SО4 iodinates successfully alkylbenzenes, aromatic amines and phenol ether. Electrophilic iodine activity is controlled by medium acidity. Super electrophilic iodine formed at N-iodoacetamide dissolution in sulfuric acid reacts easily with electron-deficient arenes at 0...20 °C forming iodinated product
Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives
It was shown that the reaction of 2-cyanothioacetamides with hydrazine involves both cyano- and thioamide groups, and 3,5-diaminopyrazoles are formed. In the reaction of 2-cyano-3-(dimethylamino)-N, N-dimethylprop-2-enethioamides with hydrazine and its derivatives, the interaction proceeds with the participation of cyano- and enamine groups, not affecting the thiocarbamoyl group, and leads to the formation of 4-thiocarbamoylpyrazoles. A synthesis method has been developed and a series of 1-substituted-4-thiocarbamoyl pyrazoles has been thus synthesized. The structure of the reaction products was studied using NMR spectroscopy and mass spectrometry and confirmed by X-ray diffraction analysis. © 2023 Filimonov et al.Russian Science Foundation, RSF: 23-13-00248The authors thank the Russian Science Foundation (project 23-13-00248)
Ambient and 550 oC tribological behavior of select MAX phases against Ni-based superalloys
Wear, In Press, Corrected ProofIn this paper, we report on the tribological behavior, at 25 and 550 ◦C of the following layered (MAX phase) ternary carbides: Ti2AlC, Cr2AlC,
Ta2AlC, Ti3SiC2, Ti2AlN, Ti4AlN3, Cr2GeC, Cr2GaC, Nb2SnC and Ti2SnC, tested against Ni-based superalloys, SA (Inconel-718 and Inconel-
600). The tests were performed using a pin-on-disc method at 1 m/s and 3N. At room temperature, the wear rates, WRs, were relatively high
(≥10−4 mm3/N-m) and no correlation was found between the WRs and the friction coefficients, μ. Third body abrasion is believed to be responsible
for the high WRs at this temperature. At 550 ◦C, oxidized transfer films were identified on both contact surfaces. The tribofilms comprised mostly
of Ni, Cr, Fe and O and resulted in low (<10−6 mm3/N-m) WRs and μ’s < 0.5. This result implies that the tribo-oxidation products of the Ni-based
SA tested herein (Inconel 718) are lubricious
Jets as a Probe of Dense Matter at RHIC
Jet quenching in the matter created in high energy nucleus-nucleus collisions
provides a tomographic tool to probe the medium properties. Recent experimental
results on jet production at the Relativistic Heavy-Ion Collider (RHIC) are
reviewed. Jet properties in p+p and d+Au collisions have been measured,
establishing the baseline for studying jet modification in heavy-ion
collisions. Current progress on detailed studies of high transverse momentum
production in Au+Au collisions is discussed, with an emphasis on dihadron
correlation measurements.Comment: 8 pages, 9 figures. Plenary talk given at 17th International
Conference on Ultra Relativistic Nucleus-Nucleus Collisions (Quark Matter
2004), Oakland, California, 11-17 Jan 2004. Submitted to J.Phys.
Event-by-event fluctuations at SPS
Results on event-by-event fluctuations of the mean transverse momentum and
net charge in Pb-Au collisions, measured by the CERES Collaboration at
CERN-SPS, are presented. We discuss the centrality and beam energy dependence
and compare our data to cascade calculations.Comment: 4 pages, 4 figures, proceedings to INPC2004 Goteborg, Swede
Modification of the rho meson detected by low-mass electron-positron pairs in central Pb-Au collisions at 158 A GeV/c
We present a measurement of pair production in central Pb-Au
collisions at 158 GeV/. As reported earlier, a significant excess of the
pair yield over the expectation from hadron decays is observed. The
improved mass resolution of the present data set, recorded with the upgraded
CERES experiment at the CERN-SPS, allows for a comparison of the data with
different theoretical approaches. The data clearly favor a substantial
in-medium broadening of the spectral function over a density-dependent
shift of the pole mass. The in-medium broadening model implies that
baryon induced interactions are the key mechanism to in-medium modifications of
the -meson in the hot fireball at SPS energy.Comment: Revised versio
Water/Alkali-Catalyzed Reactions of Azides with 2-Cyanothioacetamides. Eco-Friendly Synthesis of Monocyclic and Bicyclic 1,2,3-Thiadiazole-4-carbimidamides and 5-Amino-1,2,3-triazole-4-carbothioamides
The reactions of thioamides with azides in water were studied. It was reliably shown that the reaction of 2-cyanothioacetamides 1 with various types of azides 2 in water in the presence of alkali presents an efficient, general, one-step, atom-economic, and eco-friendly method for the synthesis of 1,2,3-thiadiazol-4-carbimidamides 5 and 1,2,3-triazole-4-carbothioamides 4. This method can be extended to the one-pot reaction of sulfonyl chlorides and 6-chloropyrimidines 2′o with sodium azide, leading to final products in higher yields, that is, avoiding the isolation of unsafe sulfonyl azides. The method was furthermore applied to the reaction of N,N′-bis-(2-cyanothiocarbonyl)pyrazine 1h with sulfonyl azides to afford bicyclic 1,2,3-thiadiazoles 8 and 1,2,3-triazoles 9 connected via a 1,1′-piperazinyl linker. 2-Cyanothioacetamides 1 were also shown to react with aromatic azides in water in the presence of alkali to afford 1-aryl-5-amino-1,2,3-triazole-4-carbothioamides 11. In contrast to aromatic azides and similarly to sulfonyl azides, 6-azidopyrimidine-2,4-diones 2o-q react with cyanothioacetamides to form N-pyrimidin-6-yl-5-dialkylamino-1,2,3-thiadiazole-4-N-l-carbimidamides 12. A mechanism was proposed to rationalize the role of water in changing the reactivity of azides toward 2-cyanothioacetamides. Copyright © 2019 American Chemical Society.We gratefully acknowledge financial support of this work by the Russian Science Foundation (18-13-00161)
New Results on Pb-Au Collisions at 40 AGeV from the CERES/NA45 Experiment
In 1999 the CERES/NA45 ran at the CERN SPS with a beam energy of 40
GeV/nucleon. The data set comprises about 8.7 millions Pb-Au events with a
trigger selection corresponding to approximately the most central 30% of the
geometrical cross section. Results on low-mass electron pair analysis are
presented.
The upgrade of the experimental setup with the radial drift TPC has allowed
to enhance hadron physics capabilities of the experiment. New results on hadron
spectra (including Lambda) and flow are presented.Comment: Talk at the International Nuclear Physics Conference INPC2001,
Berkeley, CA, July 29th - August 3rd 200
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