By a ball-covering B of a Banach space X, we mean that it is a collection of open balls off the origin whose union contains the sphere of the unit ball of X. The space X is said to have a ball-covering property, if it...By a ball-covering B of a Banach space X, we mean that it is a collection of open balls off the origin whose union contains the sphere of the unit ball of X. The space X is said to have a ball-covering property, if it admits a ball-covering consisting of countably many balls. This paper, by constructing the equivalent norms on l~∞, shows that ball-covering property is not invariant under isomorphic mappings, though it is preserved under such mappings if X is a Gateaux differentiability space; presents that this property of X is not heritable by its closed subspaces; and the property is also not preserved under quotient mappings.展开更多
Cobalt catalysts supported on a series of mesoporous SBA-15 materials isomorphically substituted with zirconium (Zr/Si atomic ratio=1/20) with different pore sizes (5.7 nm,7.8 nm,11.6 nm,17.6 nm) have been synthesized...Cobalt catalysts supported on a series of mesoporous SBA-15 materials isomorphically substituted with zirconium (Zr/Si atomic ratio=1/20) with different pore sizes (5.7 nm,7.8 nm,11.6 nm,17.6 nm) have been synthesized.The catalysts were characterized by transmission electron microscopy,29 Si solid state magic angle spinning (MAS)NMR,N2 adsorption-desorption measurements,X-ray powder diffraction,X-ray photoelectron spectroscopy,H2-temperature programmed reduction,H2-temperature programmed desorption and O2 titrations.The results indicated that larger pore size led to weaker interactions between cobalt and the supports which lowered the temperature of both reduction steps (Co3O4 → CoO and CoO→ Co0).The catalytic performances of the catalysts in Fischer-Tropsch synthesis (FTS) were tested in a fixed bed reactor.It was found that the FTS catalytic activity and product selectivity depended strongly on the pore size of the catalysts.The catalyst with a pore size of 7.8 nm showed the best FTS activity,and the catalyst with a pore size of 17.6 nm showed the highest selectivity to C12-C20 and C20+ hydrocarbons.展开更多
Within high-risk industries, efficient management of safety is an important element of organisational efforts to reduce accidents. Most organisations such as nuclear, aviation and oil and gas sectors have a safety man...Within high-risk industries, efficient management of safety is an important element of organisational efforts to reduce accidents. Most organisations such as nuclear, aviation and oil and gas sectors have a safety management system (SMS) which provides sequence of organisational procedure to identify hazards, mitigation of risk, measure performance, investigate incidents and maintain an on-going continuous improvement. However, experts believe that when such complex organisations complement safety management system with isomorphic lessons and organisational learning strategies to manage safety, there will be a high propensity to aggressively reduce risk and save cost. Undoubtedly, learning from accidents/incidents is one of many ways to manage safely in any given organisation. As a result, this paper is intended to ascertain if organisations use isomorphic lessons and organisational learning as strong feature of organisation’s practice capable of promoting stronger safety culture;and if lessons learned from other high-risk sectors can help inform risk-based decisions in organisations. Risk experts and by extension the nuclear sector, could have learned from past accident such as the Three Mile Island of 1979 and employ lessons learned to forestall future occurrences. Primary data was gathered via online, and research population are health and safety professionals from aviation, nuclear, and the oil and gas sectors. The sample size recruited are aviation (n = 59, 25%);nuclear (n = 124, 54%);and oil and gas (n = 49, 21%). Statistical Package for the Social Sciences (SPSS) software was used to analyse 232 responses used for this paper.展开更多
The maximum matching graph M（G） of a graph G is a simple graph whose vertices are the maximum matchings of G and where two maximum matchings are adjacent in M（G） if they differ by exactly one edge. In this paper, ...The maximum matching graph M（G） of a graph G is a simple graph whose vertices are the maximum matchings of G and where two maximum matchings are adjacent in M（G） if they differ by exactly one edge. In this paper, we prove that if a graph is isomorphic to its maximum matching graph, then every block of the graph is an odd cycle.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 10471114)
文摘By a ball-covering B of a Banach space X, we mean that it is a collection of open balls off the origin whose union contains the sphere of the unit ball of X. The space X is said to have a ball-covering property, if it admits a ball-covering consisting of countably many balls. This paper, by constructing the equivalent norms on l~∞, shows that ball-covering property is not invariant under isomorphic mappings, though it is preserved under such mappings if X is a Gateaux differentiability space; presents that this property of X is not heritable by its closed subspaces; and the property is also not preserved under quotient mappings.
基金supported by the National Natural Science Foundation of China(20590360 and 20773166)
文摘Cobalt catalysts supported on a series of mesoporous SBA-15 materials isomorphically substituted with zirconium (Zr/Si atomic ratio=1/20) with different pore sizes (5.7 nm,7.8 nm,11.6 nm,17.6 nm) have been synthesized.The catalysts were characterized by transmission electron microscopy,29 Si solid state magic angle spinning (MAS)NMR,N2 adsorption-desorption measurements,X-ray powder diffraction,X-ray photoelectron spectroscopy,H2-temperature programmed reduction,H2-temperature programmed desorption and O2 titrations.The results indicated that larger pore size led to weaker interactions between cobalt and the supports which lowered the temperature of both reduction steps (Co3O4 → CoO and CoO→ Co0).The catalytic performances of the catalysts in Fischer-Tropsch synthesis (FTS) were tested in a fixed bed reactor.It was found that the FTS catalytic activity and product selectivity depended strongly on the pore size of the catalysts.The catalyst with a pore size of 7.8 nm showed the best FTS activity,and the catalyst with a pore size of 17.6 nm showed the highest selectivity to C12-C20 and C20+ hydrocarbons.
文摘Within high-risk industries, efficient management of safety is an important element of organisational efforts to reduce accidents. Most organisations such as nuclear, aviation and oil and gas sectors have a safety management system (SMS) which provides sequence of organisational procedure to identify hazards, mitigation of risk, measure performance, investigate incidents and maintain an on-going continuous improvement. However, experts believe that when such complex organisations complement safety management system with isomorphic lessons and organisational learning strategies to manage safety, there will be a high propensity to aggressively reduce risk and save cost. Undoubtedly, learning from accidents/incidents is one of many ways to manage safely in any given organisation. As a result, this paper is intended to ascertain if organisations use isomorphic lessons and organisational learning as strong feature of organisation’s practice capable of promoting stronger safety culture;and if lessons learned from other high-risk sectors can help inform risk-based decisions in organisations. Risk experts and by extension the nuclear sector, could have learned from past accident such as the Three Mile Island of 1979 and employ lessons learned to forestall future occurrences. Primary data was gathered via online, and research population are health and safety professionals from aviation, nuclear, and the oil and gas sectors. The sample size recruited are aviation (n = 59, 25%);nuclear (n = 124, 54%);and oil and gas (n = 49, 21%). Statistical Package for the Social Sciences (SPSS) software was used to analyse 232 responses used for this paper.
基金Supported by National Natural Science of Foundation of China (Grant Nos. 10531070, 10721101)KJCX YW-S7 of CAS
文摘The maximum matching graph M（G） of a graph G is a simple graph whose vertices are the maximum matchings of G and where two maximum matchings are adjacent in M（G） if they differ by exactly one edge. In this paper, we prove that if a graph is isomorphic to its maximum matching graph, then every block of the graph is an odd cycle.
