Reaction of 1,2,4-triazole-3-thiones with 1-chloro-2,3-epoxypropane

Addition of 1-chloro-2,3-epoxypropane to 1,2,4-triazole-3-thiones depending on the ratio of the reactants leads to the formation of 3-(1-chloro-2-hydroxypropyl)-3-(1-chloro-2-hydroxypropylthio)-1,2,4-triazoles. 3-Hydroxy-1,2,4-triazolo[2,3-b] tetrahydro-1,3-triazines have been synthesized by intramolecular cyclization of the monoadducts.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 271–274, February, 1987     

Contact interaction and relaxation effects in paramagnetic complex of Eu(dpm)3 with 3- and 5-hydroxyflavone

Conclusions A mechanism was proposed for the transfer of the contact hyperfine coupling in the paramagnetic complexes of lanthanides with organic ligands on the example of the 3- and 5-hydroxyflavones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1878–1880 August, 1977.The author expresses his gratitude to N. N. Pogodaeva for supplying the samples of (I) and (II), and also to Yu. L. Frolov for helpful discussion.     

Open-Closed Moduli Spaces and Related Algebraic Structures

We set up a Batalin–Vilkovisky Quantum Master Equation (QME) for open-closed string theory and show that the corresponding moduli spaces give rise to a solution, a generating function for their fundamental chains. The equation encodes the topological structure of the compactification of the moduli space of bordered Riemann surfaces. The moduli spaces of bordered J-holomorphic curves are expected to satisfy the same equation, and from this viewpoint, our paper treats the case of the target space equal to a point. We also introduce the notion of a symmetric Open-Closed Topological Conformal Field Theory (OC TCFT) and study the L _∞ and A _∞ algebraic structures associated to it.     

Invertible architectures from amphiphilic polyesters

We synthesized and characterized novel amphiphilic polyesters with both hydrophilic and hydrophobic functionalities. The polyesters are soluble in organic and aqueous media and reveal the formation of inverse architectures whose behavior could be correlated to their chemical structure. We foresee that the amphiphilic properties of the polyesters reported here are obviously the basis of new architectures both in solution and on the solid surfaces, which could be used in a broad range of applications. The described synthesis of the copolymers is very simple and is based on commercially available products. That makes this approach attractive in various uses.     

Boundary slip and wetting properties of interfaces: correlation of the contact angle with the slip length

Correlations between contact angle, a measure of the wetting of surfaces, and slip length are developed using nonequilibrium molecular dynamics for a Lennard-Jones fluid in Couette flow between graphitelike hexagonal-lattice walls. The fluid-wall interaction is varied by modulating the interfacial energy parameter epsilonr=epsilonsfepsilonff and the size parameter sigmar=sigmasfsigmaff, (s=solid, f=fluid) to achieve hydrophobicity (solvophobicity) or hydrophilicity (solvophilicity). The effects of surface chemistry, as well as the effects of temperature and shear rate on the slip length are determined. The contact angle increases from 25 degrees to 147 degrees on highly hydrophobic surfaces (as epsilonr decreases from 0.5 to 0.1), as expected. The slip length is functionally dependent on the affinity strength parameters epsilonr and sigmar: increasing logarithmically with decreasing surface energy epsilonr (i.e., more hydrophobic), while decreasing with power law with decreasing size sigmar. The mechanism for the latter is different from the energetic case. While weak wall forces (small epsilonr) produce hydrophobicity, larger sigmar smoothes out the surface roughness. Both tend to increase the slip. The slip length grows rapidly with a high shear rate, as wall velocity increases three decades from 100 to 10(5) ms. We demonstrate that fluid-solid interfaces with low epsilonr and high sigmar should be chosen to increase slip and are prime candidates for drag reduction.     

Synthesis of New Amphiphilic Comb-Like Copolymers Based on Maleic Anhydride and α-Olefins

Summary: Novel amphiphilic comb-like poly(α-olefin-co-maleic anhydride) with a controlled ratio of hydrophilic (polyoxyethylene) and hydrophobic (polymethylene) side chains have been synthesized and characterized. The comb-like copolymers are soluble in organic and aqueous media and form micelles whose behaviour could be correlated to the chemical structure of polymers. We foresee that amphiphilic properties of the novel comb-like polymers are obviously the basis of new architectures in solution which could be used in a broad range of applications. Using micelles from these copolymers, silver nanoparticles with a narrow particle size distribution have been obtained as stable dispersion in both polar and non-polar media.     

Investigation of antirelaxation coatings for alkali-metal vapor cells using surface science techniques

Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10?000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C[Double Bond]C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials.     

Synthesis of Ba<Subscript>4</Subscript>R<Subscript>3</Subscript>F<Subscript>17</Subscript> (R stands for rare-earth elements) powders and transparent compacts on their base

Single-phase samples of Ba₄R₃F₁₇ · nH₂O (R = La, Ce, Pr, Nd, Eu, Gd, Y, Er, or Yb; n = 2.5−3.2) were prepared by coprecipitation from nitrate solutions using hydrofluoric acid. The phases crystallize in a fluorite-type face-centered cubic lattice. The dried precipitates are transparent. Scanning electron and atomic-force microscopy and X-ray diffraction line broadening show a hierarchic structure in the samples: primary nanoparticles join into agglomerates with characteristic sizes of about 150–200 nm, these agglomerates being self-packed into parallel layers with a thickness on the order of 500 nm.     

Ground state correlations and structure of odd spherical nuclei

It is well known that the Pauli principle plays a substantial role at low energies because the phonon operators are not ideal boson operators. Calculating the exact commutators between the quasiparticle and phonon operators, one can take into account the Pauli principle corrections. Besides, the ground state correlations due to the quasiparticle interaction in the ground state influence the single-particle fragmentation as well. In this paper, we generalize the basic equations of the quasiparticle-phonon nuclear model to account for both effects mentioned. As an illustration of our approach, calculations on the structure of the low-lying states in ¹³³Ba have been performed. The text was submitted by the authors in English.     

Rotational isomerism in 1-vinylpyrazoles and 1-vinylimidazoles from 1H and 13C NMR data and quantum-chemical calculations

A quantitative evaluation of the percentages of rotational isomers of 1-vinylpyrazoles and 1-vinylimidazoles was made on the basis of an analysis of the ¹H and ¹³C NMR spectral parameters and quantum-chemical calculations. It is shown that the populations of the s-cis-(N₍₂₎, N₍₃₎) and s-trans-(N₍₂₎, N₍₃₎) forms in both the 1-vinylpyrazole and in the 1-vinylimidazole are approximately equal.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1346–1351, October, 1990.