Jianbo Zhu

Meta‐analysis of amiodarone versus beta‐blocker as a prophylactic therapy against atrial fibrillation following cardiac surgery

Current guidelines recommend beta‐blocker as the first‐line preventive treatment of atrial fibrillation (AF) after cardiac surgery; if beta‐blocker therapy is contraindicated, then amiodarone is recommended. There is still lack of strong evidence of directly comparing the efficacy of amiodarone and beta‐blocker in preventing postoperative AF (POAF).

Study on capacitance evolving mechanism of polypyrrole during prolonged cycling.

A simple model on the evolution mechanism of PPy capacitance during prolonged cycling offers a reasonably description on the rapid increase and decay of PPy capacitance in 1 M 1-ethyl-3-methylimidazolium tetrafluoroborate/propylene carbonate (EtMeImBF4/PC). The capacitance of PPy films reached a very high specific capacitance of 420 F·g(-1) after 15 cycles when they worked in 1 M MeEt3ImBF4/PC. However, the capacitance rapidly decreased to 5% after only 400 cycles. The electronic conductivity and protonation level on the nitrogen site of PPy films rapidly decreased with the increase of cyclic number. The salt of EtMeImBF4 was monitored in PPy matrix by FTIR spectra after 400 cycles. The EQCM results indicated that a lot of 1-ethyl-3-methylimidazolium cations (EtMeIm(+)) were inserted during reduction process and retained in PPy matrix. The detained EtMeIm(+) cations bonded with doped p-toluenesulfonate anions (PTS(-)) in PPy matrix or BF4(-) anions from electrolyte and formed salts. Small amount of salts in PPy matrix can open more channels of ion insertion and resulted in a very high capacitance after 15 cycles. The continuous combination of detained EtMeIm(+) cations with doping anions of PTS(-) resulted in the rapid decrease of PPy protonation level on the nitrogen site and formation of compensate semiconductor state in PPy matrix. This should be responsible for the rapid decay of PPy conductivity and capacitance. The continuous accumulation of salts resulted in the great increase of PPy internal resistance.

Effect of cohesive powders on pressure fluctuation characteristics of a binary gas-solid fluidized bed

The effect of cohesive particles on the pressure fluctuations was experimentally investigated in a binary gas-solid fluidized bed. The pressure fluctuation signals were measured by differential pressure sensors under conditions of various weight percentages of cohesive particles. The cohesive particles increased the fixed bed pressure drop per unit height and decreased the minimum fluidization velocity. The Wen & Yu equation well predicts the minimum fluidization velocity of the binary system. The addition of cohesive particles slightly decreased the bubble size in bubbling flow regime when the cohesive particles and the coarse particles mixed well, while the bubble size greatly decreased when the cohesive particles agglomerated on the bed surface. The time series of pressure fluctuations was analyzed by using the methods of time domain, frequency domain and wavelet transformation. The normalized standard deviation of pressure fluctuations decreased with increasing weight percentages of cohesive particles. A wide bandwidth frequency of 0 to 1Hz got narrower with a single peak around 0.6Hz with an increase in proportion of the cohesive particles. The meso-energy and micro-energy of pressure fluctuations were decreasing with increasing cohesive particles proportions, which indicated that adding cohesive particles could reduce the energy dissipation of bubble and particle fluctuations.