RESUMEN
The pivotal steps for the practical application of dehydrogenation of aluminum hydride (AlH3) have been to decrease the temperature and increase the content of AlH3. Herein, the initial dehydrogenation temperature of AlH3 decreased to 43 °C with the amount of released hydrogen of 8.3 wt % via introducing TiO2 and Pr6O11 with synergistic catalysis effects, and its apparent activation energy of the dehydrogenation reaction decreased to 56.1 kJ mol-1, which is 52% lower than that of pure AlH3. These differences in performances of the samples are further evaluated by determining the electron density of Al-H bonds during dehydrogenation. The multiple valence state conversions of TiO2 and Pr6O11 promoted the electron transfer of H in AlH3, and a novel dehydrogenation pathway of PrH2.37 formed simultaneously, which could accelerate the breakage of Al-H bonds. The density functional theory calculations further exhibit that there are fewer electrons around H in AlH3 and the Al-H bond energy is weaker at the atomic levels, which is more conducive to the release of hydrogen. A higher hydrogen storage capacity and a lower dehydrogenation temperature make AlH3 one of the most promising hydrogen source media for mobile applications.
RESUMEN
OBJECTIVE: To study diagnosis and therapeutic efficacy of transient oeteoporods of the hip (TOH). METHODS: From January 2005 to February 2010, 5 patients with TOH were treated with traditional methods. All the patients were male, with an average age of 38.6 years (ranged, 27 to 46 years). The clinical manifestation, physical examination and imageology characteristic was investigated. The therapeutic efficacy was evaluated by Harris hip score. RESULTS: All the patients were followed up, the duration ranged from 12 to 36 months (averaged, 24 months). The Harris hip score before treatment were 63.1, 86.0, 74.9, 63.6 and 64.8 respectively, while after 6 months treatment, the scores improved to 90.5, 94.5, 89.7, 93.9 and 87.8 respectively. Moreover, 6 months later, the abnormal signal disappeared in MR imaging and X-ray. CONCLUSION: Transient osteoporosis of the hip is a self-resolving condition and a self-limited disease, the expectant treatment is useful for it.