Analysis of hydrogen bonds by the IR spectra of thymine and N<Subscript>1</Subscript>,N<Subscript>3</Subscript>-deuterothymine

Calculations of the frequencies and absolute intensities of the IR bands of plane vibrations of thymine and N₁,N₃-deuterothymine in various phase states have been carried out. It has been shown that in the polycrystalline state thymine forms hydrogen bonds C₂=O₈...HN₁ and C₂=O₈...HN₃, and in an aqueous solution the intermolecular interaction is realized by means of the hydrogen bonds O₈...HO and O...HN₁.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 1, pp. 99–105, January–February, 2005.     

Non-Fermi liquid theory of quantum Hall effects

Within the Grassmannian U(2N)/U(N) × U(N) nonlinear σ-model representation of localization, one can study the low-energy dynamics of both a free and interacting electron gas. We study the crossover between these two fundamentally different physical problems. We show how the topological arguments for the exact quantization of the Hall conductance are extended to include the Coulomb interaction problem. We discuss dynamical scaling and make contact with the theory of variable range hopping.     

Using an infrasonic method to monitor the destruction of glaciers in Arctic conditions

We study the application of an infrasonic method to detect infrasonic acoustic emission caused by the destruction of glaciers in the Arctic. We consider the main approaches and methods for automatic signal detection from the data of infrasonic microarrays from the viewpoint of their practical use in conditions of frequent and significant variations in the noise level characteristics of the Arctic coast. We propose a novel method for the automatic detection of infrasonic events based on representation of a plane wave signal and adaptive estimation of the noise level. The method makes it possible to detect signals with a small number of sensors (up to three) in the specific conditions of the Arctic coast. We present the results of infrasonic monitoring of the destruction of Icefjord outlet glaciers (Spitsbergen archipelago) carried out by the Kola Branch of the RAS Geophysical Survey in 2011–2012.     

On the electrodynamics of an absorbing uniaxial nonpositive determined (indefinite) medium

It is shown that a surface plasmon, whose decay length infinitely increases as it approaches the threshold frequency, can propagate over the surface of a half-space filled with a uniaxial indefinite absorbing metamaterial. At the threshold frequency itself, a new phenomenon is observed-upon incidence of a TM-polarized wave on the absorbing material, a real Brewster angle exists, and in the case of a plate made of such a metamaterial, ??reflectionless?? reflection is observed when two plane waves are incident on the plate from two sides. In the latter case, complete destructive interference of reflected and transmitted waves occurs.     

4-Thionazolidones,derivatives and analogs

A hitherto unknown isomer of rhodanine, 4-thiothiazolid-2-one (isorhodanine), is prepared by boiling thiazolidine-2, 4-dione with P₂S₅ in anhydrous dioxane for 3 hr. Isorhodanine I is characterized by great reactivity of the methylene and thione groups. The 4-phenylhydrazone and 4-phenylimino derivatives of I are prepared, as well as condensation products obtained by condensing I with aromatic aldehydes and diazonium salts. 5-Methylisorhodanine is also prepared. A derivative of I containing a quinoline ring is further obtained by reacting I with anthranilaldehyde.For Part II see [2].     

Calculation of normal vibrations of adenine and its deuterium-substituted analogs

The vibrational spectra of adenine and its deuterium-substituted analogs are calculated in the valence force field approximation. The frequencies and forms of normal vibrations of the molecule at 1700–300 cm^-1 are interpreted. Translated fromZhumal Struktumoi Khimii, Vol. 38, No. 2, pp. 324–333, March–April, 1997.     

铕(Ⅲ)荧光增敏体系在微乳液中的发光性质和荧光衰减动力学研究

利用稳态和瞬态光谱方法研究了不同铕离子发光体系中各种因素对铕离子发光性质的影响.通过吸收和激发光谱的变化分析了稀土离子Gd³⁺对Eu³⁺增敏机理,并从荧光衰减动力学角度证明了主配体噻吩甲酰三氟丙酮(TTA)、协配体邻啡咯啉(Phen)、稀土离子Gd³⁺和表面活性剂TX-100对铕离子发光的增敏作用.4种发光体系Eu³⁺/Gd³⁺/TTA/Phen/TX-100,Eu³⁺/TTA/Phen/TX-100,Eu³⁺/Gd³⁺/TTA/Phen和Eu³⁺/Gd³⁺/TTA/TX-100中铕离子⁵D₀态的发光寿命依次为980>670>400>260μs,而且存在铕离子⁵D₁到⁵D₀的传能过程.在发光越强的体系中,⁵D₁的衰减越慢,相应地⁵D₀的上升时间也就越长.研究结果表明,在最佳发光体系中既存在分子内的能量转移,又存在分子间的能量传递.     

带荧光基团蒽的正庚醛和正丁醛ReSOrcinarenes母体衍生物的合成研究

合成正庚醛、正丁醛Resorcinarenes母体,经生成酯衍生物后同－9蒽甲醇反应,合成了带荧炮光基团蒽的正庚醛、正丁醛Resorcinarenes母体衍生物,考察了各种因素对产物产率的影响,并给出了产物的IR,^1H NMR,MS及UV谱数据。     

New insights into water‐soluble and water‐coordinated copper 15‐metallacrown‐5 gadolinium complexes designed for high‐field magnetic resonance imaging applications

The development of contrast agents specifically designed for high‐field magnetic resonance imaging (MRI) is required because the relaxation efficiency of classic Gd(III) contrast agents significantly decreases with increasing magnetic field strengths. With an idea of exploring the unique structure of lanthanide (Ln) 15‐MC‐5 metallacrowns, we developed a series of water‐soluble Gd(III) aqua‐complexes, bearing aminohydroxamate (glycine, α‐alanine, α‐phenylalanine and α‐tyrosine) ligands, with increasing number of water molecules directly coordinated to the Gd(III) ion: Gd(H₂O)₄[15‐MC_Cu(II)Glyha‐5](Cl)₃ ( 1 (Gd)), Gd(H₂O)₄[15‐MC_Cu(II)Alaha‐5](Cl)₃ ( 2 (Gd)), Gd(H₂O)₃[15‐MC_{Cu(II)Phalaha}‐5](Cl)₃ ( 3 (Gd)) and Gd(H₂O)₃[15‐MC_Cu(II)Tyrha‐5](Cl)₃ ( 4 (Gd)). In these systems, the Ln(III) central ion is coordinated by five oxygen donor atoms of the ligands and three or four inner‐sphere water molecules. The X‐ray crystal structure of metallacrown Ln(H₂O)_3,4[15‐MC_Cu(II)Rha‐5]³⁺ agrees with density functional theory predictions. The calculations demonstrate that the exchange of coordinated water molecules can proceed easily, resulting in increased relaxivity parameters. The longitudinal relaxivities (r₁) of 1 (Gd)– 4 (Gd) in water at ultrahigh magnetic field of 9.4 T were determined to be 11.5, 14.8, 13.9 and 12.2 mM^?1 s^?1, respectively. The ability to increase the number of Ln(III) inner‐sphere water molecules up to four, the planar metallacrown structure and the rich hydration shell due to strong hydrogen bonds between the [15‐MC‐5] moiety and bulk water molecules provide new opportunities for potential MRI applications.     

Efficient Removal of Lead from Washing Effluent of Lead-contaminated Soil with Garlic Peel

Wastewater produced from the soil washing process contains heavy metals, which limits its reuse for washing. So it is necessary to develop an efficient and economical way to recycle it, and this study presented a biosorption method to realize this goal. A typical soil sample contaminated by lead was taken from the real field near a lead smelting factory, used for the toxic metals extraction with dilute citric acid. A leach liquor was obtained with lead ions at the level of 12.35 mg/L, Cd 1.2 mg/L, Cu 1.5 mg/L, Zn 2.6 mg/L, as well as the coexisting anions, such as sulphate, silicate, chloride at the concentration of several hundred miligram per liter. The garlic peel was modified by a simple chemical saponification process and used as the biosorbent for toxic metal removal. Firstly, the adsorption behavior of lead ions on the saponified garlic peel was systematically investigated using the synthetic solutions, and then the adsorption mechanisms were explored by detailed experiments combining with the thermodynamic calculation reuslts of the aqueous system of Pb(Ⅱ)-citrate-H₂O. It was found that in artificial solution containing 0.01 mol/L citrate, the maximum adsorption capacity of 261.0 mg/g was reached at pH near 3.0, and also at this very pH value the Pb²⁺ and Pb(H₂Cit)⁺ were the dominant lead species, which are favorable for adsorption due to its easier approaching to the -COO^- ligands in the saponified garlic peel partilces via charge attraction, and the appearance of Pb(HCit)⁰ and Pb(Cit)^- at pH above 3.0 inhibits the adsorption. Secondly, the real leach liquor was used for adsorption tests, and twice adsorption under the optimal conditons would decrease the residual concentrations of Pb, Cd, Cu and Zn to zero. After elution by using 0.1 mol/L nitric acid, the adsorbed metals can be recovered and garlic peel can be reused for at least 10 cycles effectively. This study presents a prospective biosorption method for economical and efficient removal of the lead ions from soil washing wastewater with citric acid as the leaching reagent.