RESUMEN
The mass transport and ion conductivity in the catalyst layer are important for fuel cell performances. Here, we report an in situ-grown ultrathin catalyst layer (UTCL) to reduce the oxygen mass transport and a surface ionomer-coated gas diffusion layer method to reduce the ion conducting resistance. A significantly reduced catalyst layer thickness (ca. 1 µm) is achieved, and coupled with the ionomer introduction method, the ultrathin catalyst layer is in good contact with the membrane, resulting in high ion conductivity and high Pt utilization. This ultrathin catalyst layer is suitable for both proton exchange membrane fuel cells and anion exchange membrane fuel cells, giving peak power densities of 2.24 and 1.11 W cm-2, respectively, which represent an increase of more than 30% compared with the membrane electrode assembly (MEA) fabricated by using traditional Pt/C power catalysts. Electrochemical impedance spectra and limiting current tests demonstrate the reduced charge transfer, mass transfer, and ohmic resistances in the ultrathin catalyst layer membrane electrode assembly, resulting in the promoted fuel cell performances.
RESUMEN
OBJECTIVE: To discuss the impacts of moxibustion for regulating spleen and stomach function on the survival quality of the patients of end stage renal disease (ESRD) with maintenance hemodialysis (MHD). METHODS: One hundred and nine cases of uremia with MHD from 3 hemodialysis centers were randomized into an observation group (58 cases) and a control group (51 cases). The regular hemodialysis and conventional medication were used in the two groups. In the observation group, on the basis of the common treatment, moxibustion was applied to Zusanli (ST 36) and Sanyinjiao (SP 6), 2-3 times a day, the treatment of 4 weeks made one session. Totally, 3 sessions were required and the follow-up lasted for 3 months. KDQOL-SF (kidney disease quality of life short form,KDQOL-SFTM 1. 3) was adopted for the questionnaire investigation on survival quality before treatment, after treatment and at the end of follow-up separately in the two groups. RESULTS: After treatment, the survival quality scores in terms of physical functioning (83.62+/-13.27 vs 79.32+/- 22. 17), general health (58. 88+/- 20.24 vs 48.82+/-20.89) and vitality (77.07+/-15.56 vs 70. 59+/-22.61) in the observation group were higher than those in the control group (all P<0. 05). In comparison before and after treatment in the same group, the survival quality scores in terms of physical functioning, general health, vitality and symptoms/problems were all improved in the observation group (all P<0. 05). At the end of follow-up, the survival quality scores in terms of physical functioning, general health, mental health, social functioning, vitality, effects of kidney disease and cognitive function were higher in the observation group as compared with those in the control group (all P<0. 05). In comparison of the results at the end of follow-up with those before treatment, the survival quality scores in terms of vitality, symptoms/problems and cognitive function in the observation group were improved (all P< 0. 05). The differences were not significant in all of the 19 fields of survival quality evaluation before and after treatment, and after follow-up in the control group (all P>0. 05). CONCLUSION: Moxibustion for regulating spleen and stomach function improves the survival quality of the patients with hemodialysis in terms of physical functioning, general health and vitality, which benefits the psychological condition of the patients, resulting in the improvements of the survival quality in the fields of mental health, social functioning, effects of kidney disease and cognitive function.