1,3-Dipolar cycloaddition of diphenylnitrilimine and 5-arylmethylidene-1-phenyl-1,5,6,7-tetrahydro-4H-indazol-4-ones to afford novel spiro[indazole-5,3′-pyrazole] derivatives

Chemistry of Heterocyclic Compounds - Novel 4'-aryl-1,2',5'-triphenyl-2',4',6,7-tetrahydrospiro[indazole-5,3'-pyrazol]-4(1H)-ones have been synthesized in moderate yields by...     

Effects of Side-Chain Substituents in Benzo-15-Crown-5 on Lithium Extraction

Chloroform–water extraction systems have been studied using crown-ethers as extracting agents, namely: benzo-15-crown-5 (B15C5), 2,3-naphtho-15-crown-5 (N15C5), 4′-nitro-benzo-15-crown-5 (NO₂B15C5), 4′-tert-butyl-benzo-15-crown-5 (TBB15C5), and 4′-acetyl-benzo-15-crown-5 (AcB15C5). Extraction isotherms of these systems have been obtained, and an attempt made to elucidate the effect of the structure of extracting agent on extraction characteristics. IR-spectroscopic studies have been performed for selected crown-ethers and their complexes in crystalline form and in chloroform solutions, namely, for N15C5, NO₂B15C5, AcB15C5, and B15C5. The complexes LiN15C5H₂OClO₄ (1), LiN15C5H₂OI (2), LiNO₂B15C5H₂OI (3), LiAcB15C5H₂OI (4), and LiTBB15C5H₂OI (5) have been isolated for the first time and characterized by IR spectroscopy. Single-crystal X-ray data have been obtained for complexes 1–3.     

Low-waste production of alumina catalysts for gas sulfur recovery

A new low-waste technology for production of the alumina catalyst at the Claus process has been developed. The catalytic activity of the Claus alumina catalysts (IC-27-22) produced by this technology is close to that of the best foreign samples (CR and S-100).VNIIGAS     

Kinetics and mechanism of copper fracture during deformation in surface-active baths

Relations have been derived here between the macroscopic characteristics of liquid metal embrittlement (durability _c under creep and strain _c prior to rupture under tension) and the parameters which characterize the micromechanism of fracture (surface energy at the crystal bath interface, energy of grain boundaries, temperature, structure of the crystal-bath interface, etc.), on the basis of test data indicating that the subcritical stage of microcrack development governs the fracture process, and on the assumption that transition to supercritical fracture occurs when the crack angle at the tip opens to its critical width _c. It is also shown here that, as the rate of subcritical crack development changes by three orders of magnitude, the magnitude of the critical angle _c changes only by a factor of 3.0 and may, to the first approximation, be regarded as independent of the bath composition. The values of _c and _c calculated according to this approximation agree closely enough with values based on tests.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 22–29, July, 1976.     

Molecular design of macrocyclic extractants for extraction and separation of alkali and alkaline-earth metals

The distribution coefficients of the alkaline and alkali-earth metal nitrates are determined for the processes of extraction from nitric acid solutions with crown ethers, which differ in sizes of their cycles (from 18 to 22 atoms) and in side phenyl and cyclohexyl substituents, but have unchanged number of the O atoms in a cycle. The phenyl and cyclohexyl derivatives of 18-crown-6 are found to be more efficient extractants of alkali metals as compared with unsubstituted crown ethers. However, the selectivity of separation of a pair Cs-Na remains low. The 18-crown-6 derivatives with one and two cyclohexyl fragments selectively extract Sr, which can be used to separate it from the remaining alkali and alkaline-earth metals. An increase in the size of a macrocycle from 18 to 20 and 22 atoms leads to a reduction in the extraction efficiency for all alkali and alkaline-earth metals, insignificantly improves separation of a pair Cs-Na, but noticeably deteriorates Sr-Na separation.     

Structure and electric properties of BaCe0.77 ? xZrxGd0.2Cu0.03O3 ? δ

In the present work, samples with the composition of BaCe_{0.77 − x} Zr _x Gd_0.2Cu_0.03O_{3 − δ} (x = 0, 0.1…0.7, 0.77) were synthesized according to the standard solid state technique. The effect of zirconium oxide on the phase character, structure, and conductivity was studied using the methods of X-ray diffraction analysis, scanning electron microscopy, and four-probe method, accordingly. Stability of these materials in the flow of carbon dioxide was studied. The results show that introduction of zirconium oxide leads to preservation of a single-phase system (x ≤ 0.6), a decrease in the grain size, and an increase in stability in the CO₂ atmosphere.     

Parametric generation of low-frequency sound in the propagation of high-intensity modulated noise

With the use of the one-dimensional Burgers equation, the evolution of a high-intensity noise with periodically modulated intensity is analyzed. The nonlinearity is shown to lead to partial suppression of the amplitude modulation and to the generation of a regular low-frequency component. The probability distributions and the power spectra of the field are studied.     

Immobilization of fluorescent protein TagGFP2 on Fe3O4-based magnetic nanoparticles

Russian Chemical Bulletin - The immobilization of fluorescent protein TagGFP2 on Fe3O4-based magnetic nano particles (MNPs), preliminarily functionalized with 3-aminopropylsilane and...     

Numerical simulation for the simple shear test in amorphous glassy polymers

In this paper, a driving stress finite element method of elastic-plastic large deformation based on implicit time integrating algorithm and an eight-chain molecular network model is used for the numerical simulation of the simple shear test of polycarbonate (PC) materials. The simulated results are compared with experimental ones. The strain localization propagation for the shear band deformation for simple shear deformation is investigated numerically. The effects of microstructure parameters in the model on strain softening and orientation hardening of the PC are discussed in detail. Supported by the National Natural Science Foundation of China.