ABSTRACT
The effects of ship vibrations on the mass transfer and performance of proton exchange membrane fuel cells (PEMFCs) have many vague aspects. Hence, the method of loading ship vibrations with the sliding mesh is first proposed in this paper. Furthermore, this method is adopted to form the solution of the simulation study of PEMFC performance under ship vibrations. In the framework of computational fluid dynamics, the ship vibration is loaded into the three-dimensional PEMFC model and successfully solved. Then, a series of special cases are performed to explore the gas distribution and output features of PEMFCs in ship environments with different vibrations. Finally, the results show that the ship vibrations have vectorial effects on the gas transfer in the PEMFC. Additionally, vibrations perpendicular to the channel evidently affect the gas transfer. Moreover, while the vibrations are parallel to the channel, they remain nearly normal. Relatively, a more significant influence on the output voltage of the PEMFC will occur under smaller frequencies and/or greater amplitudes of ship vibrations.
ABSTRACT
Objective To observe the bacterioflora of bile and it' s drugs sensitivity in patients with bile duct diseases to serve as a guidance in medication. Methods Bile of 156 cases of patients with biliary disease was collected and cultured respectively during endoscopic retrograde cholangiopancreatography (ER-CP) by deep cannulation and sucking out bile through the catheter. Forty eight blood samples among them were cultured simultaneously. Ten kinds of drug papers were used to investigate the bacterial sensitivity. The data were analysed statistically- Results Bacteria positive rate of these 156 bile samples was 62. 8% , including Gram - negative bacteria (81.6% ) and Gram - positive bacteria (18. 4% ). These bacteria consist of Pseudomonas aeruginosa (35. 1% ) , Escherichia coli(22. 8% ) , Streptococcus faecalis (16.7%) ,Entero bacilliaerogenes(7. 9% ) ,Klebsiella(7. 0% ) , Citrobacter(6. 1% ) ,Acinetobacler lwqffi(2. 6% ) and Staphylo-coccus aureus( 1. 7% ). The bacteria positive rate was only 4. 2% in the 48 blood samples. Drug sensitive rates of bacteria against 10 kinds of drugs were changed in recent years. The result indicated that the sensitive rates of bacteria were significantly higher in ciprofloxacin, fortum, cefoperazone, sulbactam + cefoperazone and cilastatin than those in ampicillin,azlocillin, cefazolin sodium, eefuroxime(P
