Numerical simulation and experiment of medium flow energy field in vibrating mill

In order to solve to the technical bottleneck that powder is easy to reunite and without refining in the vibration ultrafine grinding(UFG)technology,the energy field of medium flow was studied by analyzing crushing energy and energy transfer.The numerical simulation model of medium flow based on Particle Flow Code(PFC)was established.By setting four kinds of working conditions of amplitude and frequency,the dynamic graphics and curves of the energy field(such as kinetic energy,strain energy,velocity field,force chain and so on)were obtained.In the situation of mid-frequency with large amplitude,the average speed of front medium flow was 1.3–5.03 times that of others and the low-energy region was decreased by 6%to 10%.The largest kinetic energy and strain energy were 3.25 and 2.94 times the average value of others,respectively.The diamond UFG was analyzed in new vibration mills under the conditions of low frequency with large amplitude and mid-frequency with large amplitude.Utilizing a laser particle size analyzer,it was discovered that the particle sizes d(50)in these two models were 3.840µm and 0.260µm and bandwidths were 9.940µm and 3.825µm.This highlights the effect of mid-frequency with large amplitude in particle refining and bandwidth narrowing,which is of great importance in the fields of ultra-hard particle refining research and energy utilization.

Palladium/Copper Cocatalyzed Coupling Reaction of Aroyl Hydrazides with Indoles

An unprecedented palladium/copper cocatalyzed coupling reaction of indoles with simple aroyl hydrazides has been developed under aerobic conditions. A range of aroyl hydrazides underwent palladium/copper cocatalyzed oxidative arylation with indoles open to air in a 1：1 mixture of dimethyl sulfoxide and nitromethane to give structurally diverse 2-arylindoles or 3-arylindoles in moderate to good yields. The reaction well tolerates a wide variety of functional groups such as alkoxy, halo, ester.