1,962 research outputs found
Electric Fields and Chiral Magnetic Effect in Cu + Au Collisions
The non-central Cu + Au collisions can create strong out-of-plane magnetic
fields and in-plane electric fields. By using the HIJING model, we study the
general properties of the electromagnetic fields in Cu + Au collisions at 200
GeV and their impacts on the charge-dependent two-particle correlator
(see main text for
definition) which was used for the detection of the chiral magnetic effect
(CME). Compared with Au + Au collisions, we find that the in-plane electric
fields in Cu + Au collisions can strongly suppress the two-particle correlator
or even reverse its sign if the lifetime of the electric fields is long.
Combining with the expectation that if is induced by
elliptic-flow driven effects we would not see such strong suppression or
reversion, our results suggest to use Cu + Au collisions to test CME and
understand the mechanisms that underlie .Comment: V1: 7 pages, 8 figures. V2: Add 2 new figures. Published versio
Bis[3-allyl-1-(4-cyanobenzyl)-2-methylbenzimidazolium] di-μ-bromido-bis[bromidocuprate(I)]
The asymmetric unit of the title compound, (C19H18N3)2[Cu2Br4], contains one cation and one half-anion; there is a centre of symmetry mid-way between the two Cu atoms. In the cation, the nearly planar benzimidazole ring system is oriented at dihedral angles of 75.31 (3) and 21.39 (3)° with respect to the cyanobenzyl and allyl groups, respectively. The dihedral angle between cyanobenzyl and allyl groups is 87.94 (3)°. In the crystal structure, intermolecular C—H⋯Br hydrogen bonds link the molecules. There is a C—H⋯π contact between the cyanobenzyl ring and the anion; π—π contacts also exist between the benzimidazole ring systems as well as between the anion and the cyanobenzyl ring [centroid–centroid distances = 4.024 (1) and 4.617 (1) Å, respectively]
Measurement and Simulation Study on Effective Drainage Radius of Borehole Along Coal Seam
A measurement study was conducted for the effective drainage radius of borehole along coal seam #9 of the Kaiyuan Coal Mine using the gas pressure method and gas flow method. The measurement results show that the effective drainage radius of borehole along coal seam #9 was 0.75 m, 27 days after drainage, and 1.5 m, 92 days after drainage. Experimental schemes were designed for the entire evolution of the stress in the coal mass around the borehole, and an experimental study on methane seepage in the coal mass around borehole was conducted. Fitting functions for the permeability of the coal sample and its vertical stress were obtained by fitting the experimental data. Based on the vertical stress–permeability functional relationship of coal masses around borehole, a numerical calculation model for methane seepage from coal masses around borehole was established, and the influences of drainage time, initial gas pressure, borehole diameter, and drainage negative pressure on the effective drainage radius of borehole were investigated. The numerical simulation results show that with the increase in initial gas pressure and borehole diameter, the effective drainage radius of borehole increases continuously but its increase amplitude decreases constantly. With the increase in drainage negative pressure, the effective drainage radius of borehole increases linearly but the increase amplitude is relatively small. The layout parameters of borehole along coal seam #9 of the Kaiyuan Coal Mine were optimized based on the numerical calculation results, and the reasonable drainage time, reasonable borehole diameter, and reasonable drainage negative pressure are 180 days, 120 mm, and 15 kPa, respectively, for the borehole along coal seam #9
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