Experimental Study on Atomization Characteristics of Gas-Liquid Two-Phase Flow Nozzle and Its Dust Removal Effect.

An experimental study on the flow rate and atomization characteristics of a new gas-liquid two-phase flow nozzle was carried out to use high-concentration respirable dust in the workplace of high-efficiency sedimentation coal production based on the gas-liquid two-phase flow nozzle technology. The simulation roadway of dust fall in large coal mines was constructed, and the respirable rock dust produced by fully mechanized mining surfaces was chosen as the research object. The effects of humidity on the capture effect of respirable rock dust were analyzed in the experimental study. The results demonstrated that: (1) the distribution range of the particle size of fogdrops declines with the reduction in fogdrops D50, D[3,2] and D[4,3], which are produced by gas-liquid two-phase flow nozzles. (2) The initial ambient humidity in the simulated roadway was 64.8% RH. After the gas-liquid two-phase flow spray was started, the ambient humidity was elevated by 23.2 to 23.5% RH within 840s and tended to be stable and no longer grew after reaching 88.0-88.3% RH. The initial growth rate of the ambient humidity in the simulated roadway was high, and then was gradually slowed down. (3) Humidity is an important factor influencing the collection of respirable dust. The humidity at 10.0 m leeward of the dust-producing point was increased by 19.6% RH, and the sedimentation rate of respirable dust was increased by 6.73%; the two growth rates were 13.1% RH and 9.90% at 20.0 m; 16.4% RH and 15.42% at 30.0 m; 18.4% RH and 11.20% at 40.0 m. In practical applications of the gas-liquid two-phase flow nozzle in coal mining activities, attention shall be paid to not only the influences of its atomization characteristics on the capture effect of respirable dust but also the influences of the flow rate of the nozzle on the humidity of the working surface. Appropriate gas and water supply pressures shall be chosen according to the space and respirable dust concentration on the working surface to realize a better dust removal effect.

Functionalized Lanthanide(III) Complexes Constructed from Azobenzene Derivative and ß-Diketone Ligands: Luminescent, Magnetic, and Reversible Trans-to-Cis Photoisomerization Properties.

The coordination ability of ligands functionalized by azobenzene was manipulated, and two novel chelating ligands, (E)-4-(phenyldiazenyl)-N,N-bis(pyridin-2-ylmethyl) benzohydrazide (C25H22N6O, PBPM) and (E)-4-((4-(dimethylamino)phenyl)diazenyl)-N,N-bis(pyridin-2-ylmethyl) benzohydrazide (C27H27N7O, dmPBPM), were synthesized. The ligands can offer four coordinating atoms (one oxygen and three nitrogens) to act as tetradendate ligands, together with the two ß-diketonates (4,4,4-trifluoro-1-phenylbutane-1,3-dionate, tfd), and the trifluoroacetate anion presented as a ligand and a counterion to form the quaternary units with lanthanide(III) ions (La, Eu, and Gd), [Ln(tfd)2(PBPM)(CF3CO2)] (LnC47H34F9N6O7) and [Ln(tfd)2(dmPBPM)(CF3CO2)] (LnC49H39F9N7O7), where the lanthanide(III) ions are nine coordinated with N3O6 donor sets. All six complexes were structurally characterized, and four crystals were obtained and further analyzed by means of single-crystal X-ray diffraction. They all crystallized in the monoclinic P21/c space group with very similar lattice parameters, forming a monocapped twisted square antiprism. We successfully observed the photoluminescent properties of Eu(III) complexes at a wavelength of 614 nm in both solution and the solid state, as well as the trans-to-cis photoisomerization with the quantum yield (Φt→c = 10-2) of [Eu(tfd)2(PBPM)(CF3CO2)] complex that was comparable to that of PBPM. Moreover, the trans-to-cis photoisomerization rates of complexes [Ln(tfd)2(PBPM)(CF3CO2)] (La, Eu, Gd) (10-3-10-2 s -1) were also at the same level as that of PBPM and much higher than azobenzene itself (10-5-10-4 s-1). With the aid of TD-DFT calculations, the luminescence of Eu(III) complexes was found to originate from the attenuation effect of ß-diketonates. These features provide the foundation for the development of azobenzene-derived ß-diketonates lanthanide(III) complexes with photoisomerization and photoluminescence dual functions.

4-Amino-3-(4-pyrid-yl)-1,2,4-triazole-5(4H)-thione.

In the title mol-ecule, C(7)H(7)N(5)S, the pyridyl and triazole rings form a dihedral angle of 20.07 (6)°. Inter-molecular N-H⋯N hydrogen bonds link the mol-ecules into chains extended in the direction [10]. Further stability is provided by π⋯π stacking inter-actions, indicated by short distances between the centroids of triazole rings [3.480 (5) Å] and pyridyl rings [3.574 (5) Å] of neighbouring mol-ecules.

[Study on the CD and ORD of the crystal NaClO3].

Chiral isotropy material should be obtained in order to manufacture chiral optical waveguide. In the present paper, a chiral crystal of NaClO3 was grown from water solution by standard rocking techniques. Crystal incising and optical polishing were doneand a transparent 10.9 mm x 8.2 mm x 4.7 mm crystal NaClO3 was obtained. Along the six directions perpendicular to the surface of the crystal NaClO3, its circular dichroism and UV spectra were collected, and at the same time its optical rotatory dispersion was measured by a self-fabricated ORD apparatus. It was approved by our experiment that the CD, UV spectrum and the optical rotatory dispersion of the crystal NaClO were isotropic, which is not the same as those of quartz.

Change of handedness in cholesteric liquid crystalline phase for N-phthaloylchitosan solutions in organic solvents.

The influence of concentration on the helicoidal change of N-phthaloylchitosan (PhCh) solutions in Me2SO, DMAc and DMF was investigated by means of circular dichroism (CD). The critical concentrations to form liquid crystal phase in these three solvents were 43, 45 and 48 wt.%, respectively as measured with polarized optical microscope. There were two kinds of CD peaks, sharp peaks with absorption maximum at about 330 nm induced by the helical conformation of molecular chain, and very broad peaks covering almost whole visible region induced by the cholesteric helix of mesophase. The later only appeared in concentrated solutions with the concentration higher than the critical concentration. The handedness of both levels of helicoidal structures changed from left- to right-handed with the increase of concentration for PhCh/Me2SO solutions. The chirality transfer occurred between these two chiral levels. For PhCh/DMAc and PhCh/DMF systems, only the handedness of helical conformation reversed, but the cholesteric helix did not change. As a method to measure critical concentration, CD is more sensitive than polarized optical microscopy (POM).