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Ming Au

Publications and source records attributed to Ming Au.

4 recordsLinked to original sources
PubMed2006

Modified lithium borohydrides for reversible hydrogen storage (2).

This paper reports the results of the effort to destabilize lithium borohydride for reversible hydrogen storage. Various metals, metal hydrides, and metal chlorides were selected and evaluated as destabilization agents for reducing dehydriding temperatures and improving dehydriding/rehydriding reversibility. The most effective material was LiBH4 + 0.2MgCl2 + 0.1TiCl3 which starts desorbing 5 wt % of hydrogen at 60 degrees C and can be rehydrogenated to 4.5 wt % at 600 degrees C and 70 bar. X-ray diffraction and Raman spectroscopic analysis show the interaction of LiBH4 with additives and the unusual change of B-H stretching.

Journal Article↗
PubMed2006

Modified lithium borohydrides for reversible hydrogen storage.

In an attempt to develop lithium borohydrides as reversible hydrogen storage materials with high hydrogen storage capacities, the feasibility of reducing the dehydrogenation temperature of the lithium borohydride and moderating rehydrogenation conditions was explored. The lithium borohydride was modified by ball milling with metal oxides and metal chlorides as additives. The modified lithium borohydrides released 9 wt % hydrogen starting from 473 K. The dehydrided modified lithium borohydrides absorbed 7-9 wt % hydrogen at 873 K and 7 MPa. The modification with additives reduced the dehydriding starting temperature from 673 to 473 K and moderated the rehydrogenation conditions from 923 K/15 MPa to 873 K/7 MPa. XRD and SEM analysis revealed the formation of an intermediate compound that might play a key role in changing the reaction path, resulting in the lower dehydriding temperature and reversibility. The reversible hydrogen storage capacity of the oxide-modified lithium borohydrides decreased gradually during hydriding/dehydriding cycling. One of the possible reasons for this effect might be the loss of boron during dehydrogenation, but this can be prevented by changing the dehydriding path using appropriate additives. The additives reduced the dehydriding temperature and improved the reversibility, but they also reduced the hydrogen storage capacity. The best compromise can be reached by selecting appropriate additives, optimizing the additive loading, and using new synthesis processes other than ball milling.

Journal Article↗
PubMed2003

Depression in older Chinese migrants to Auckland.

OBJECTIVE: This study was conducted to identify risk factors for depressive symptomatology among older Chinese migrants. METHOD: One hundred and sixty-two Chinese migrants aged 55 years or older, living in the community and recruited via Chinese community organizations and general practitioners, were interviewed using a Chinese version of the Geriatric Depression Scale and measures of stressful life events, morbid conditions, self-rated health, acculturation, social support and service utilization. RESULT: Twenty-six percent of participants met the criteria for depressive symptomatology. No recent migrants showed symptoms of depression. Multiple logistic regression analysis showed that lower emotional support, greater number of visits to a doctor, difficulties in accessing health services and low New Zealand cultural orientation increased the risk of showing symptoms of depression. CONCLUSION: Significant numbers of older Chinese migrants appear to be depressed or at risk for depression and, while participants with depressive symptoms consulted general practitioners more than their counterparts without such symptoms, they reported greater difficulty in accessing health services. The findings point to the need for further epidemiological study of this growing sector of the population and investigation of the nature of its engagement with health services. Social support and aspects of acculturation may play a significant role in preventing depression. This also requires further investigation.

Acculturation↗