In this work,hydrogen is produced from partial oxidation reforming of dimethyl ether （DME） by a plasma-catalyst hybrid reformer under atmospheric pressure.The plasma-catalyst hybrid reformer which includes both plas...In this work,hydrogen is produced from partial oxidation reforming of dimethyl ether （DME） by a plasma-catalyst hybrid reformer under atmospheric pressure.The plasma-catalyst hybrid reformer which includes both plasma and catalyst reactors is designed.A spark discharge is used as a non-equilibrium plasma source,and it is used to ionize the mixture of DME and air.The performances of the reformer are characterized experimentally in terms of gas concentrations,hydrogen yield,DME conversion ratio,and specific energy consumption.The effects of discharge frequency,reaction temperature,air-to-DME ratio and space velocity are investigated.The experimental results show that the plasma-catalyst hybrid reformer enhances hydrogen yield when reaction temperature drops below 620 ℃.At 450 ℃,hydrogen yield of hybrid reforming is almost three times that of catalyst reforming.When space velocity is 510 h-1,hydrogen yield is 67.7%,and specific energy consumption is 12.2 k J/L-H2.展开更多
In this paper a system combining a diesel reformer using catalytic partial oxidation （CPOX） with the Solid Oxide Fuel Cell （SOFC） for Auxiliary Power Unit （APU） applications is modeled with respect to the coolin...In this paper a system combining a diesel reformer using catalytic partial oxidation （CPOX） with the Solid Oxide Fuel Cell （SOFC） for Auxiliary Power Unit （APU） applications is modeled with respect to the cooling effect provided by internal reforming of methane in anode gas channel. A model mixture consisting of 80% n-hexadecane and 20%..!-methylnaphthalin is used to simulate the commercial diesel. The modelling consists of several steps. First, equilibrium gas composition at the exit of CPOX reformer is modelled in terms oxygen to car- bon （O/C） ratio, fuel utilization ratio and anode gas recirculation. Second, product composition, especially methane content, is determined for the me.th.an, ation process at the operating temperatures ra：ng!ng from 500 ℃to 520 ℃.Finally, the cooling power provided by internal reforming of methane in SOFC fuel channel is calculated for two concepts to increase the methane content of the diesel reformate. The results show that the first concept, operating the diesel reformer at low O/C ratio and/or, recirculation rat!o, is not realizable due to high probability of coke formation, whereas the second concept, combining a methanation process with CPOX, can provide a significant cool- ing effect in addition to the conventional c？oling concept which needs higher levels of excess air.展开更多
By introducing the partial actions of primitive inverse semigroups on a set and their globalizations, a structure theorem for E^＊-unitary categorical inverse semigroups is obtained.
Mental imagery generation is essential in the retrieval and storage of knowledge.Previous studies have indicated that the holistic properties of mental imagery generation can be evaluated more easily than the partial ...Mental imagery generation is essential in the retrieval and storage of knowledge.Previous studies have indicated that the holistic properties of mental imagery generation can be evaluated more easily than the partial properties.However,the relationship between partial and holistic mental imagery generations has not been clearly demonstrated.To address this issue,we designed a task to investigate the changes in the spectrum of the electroencephalogram (EEG) during partial or holistic imagery generation.EEG signals were obtained from 18 healthy subjects,and a statistical measure of spectral dynamics between two EEG signals in per frequency band was performed.Additionally,a bicoherence spectrum analysis was used to detect the phase coupling within these two imagery conditions.Our results indicated that EEG of the partial imagery appeared earlier and stronger than that of the holistic imagery in the theta (5–8 Hz) range in a time window around 220 to 300 ms after cue onset,and a slight decrease in the alpha (8–12 Hz) band was observed at around 270 ms.The scalp topography of these changes in the theta and alpha bands distributed overall significantly in the frontal and central-temporal areas.The significant phase coupling within two conditions was remarkable at high frequency.From these results,we infer that there are complex relations between partial and holistic imageries.The generation of partial mental imagery is not a subprocess of holistic imagery,but it is relevant to holistic imagery and requires correct modification from the holistic information.展开更多
基金Project(21106002)supported by the National Natural Science Foundation of ChinaProject(2010DFA72760)supported by Collaboration on Cutting-Edge Technology Development of Electric Vehicle,China
文摘In this work,hydrogen is produced from partial oxidation reforming of dimethyl ether （DME） by a plasma-catalyst hybrid reformer under atmospheric pressure.The plasma-catalyst hybrid reformer which includes both plasma and catalyst reactors is designed.A spark discharge is used as a non-equilibrium plasma source,and it is used to ionize the mixture of DME and air.The performances of the reformer are characterized experimentally in terms of gas concentrations,hydrogen yield,DME conversion ratio,and specific energy consumption.The effects of discharge frequency,reaction temperature,air-to-DME ratio and space velocity are investigated.The experimental results show that the plasma-catalyst hybrid reformer enhances hydrogen yield when reaction temperature drops below 620 ℃.At 450 ℃,hydrogen yield of hybrid reforming is almost three times that of catalyst reforming.When space velocity is 510 h-1,hydrogen yield is 67.7%,and specific energy consumption is 12.2 k J/L-H2.
基金Supported by the Ministry of the Environment, Climate Protection and the Energy Sector, Baden-Wuettermberg
文摘In this paper a system combining a diesel reformer using catalytic partial oxidation （CPOX） with the Solid Oxide Fuel Cell （SOFC） for Auxiliary Power Unit （APU） applications is modeled with respect to the cooling effect provided by internal reforming of methane in anode gas channel. A model mixture consisting of 80% n-hexadecane and 20%..!-methylnaphthalin is used to simulate the commercial diesel. The modelling consists of several steps. First, equilibrium gas composition at the exit of CPOX reformer is modelled in terms oxygen to car- bon （O/C） ratio, fuel utilization ratio and anode gas recirculation. Second, product composition, especially methane content, is determined for the me.th.an, ation process at the operating temperatures ra：ng!ng from 500 ℃to 520 ℃.Finally, the cooling power provided by internal reforming of methane in SOFC fuel channel is calculated for two concepts to increase the methane content of the diesel reformate. The results show that the first concept, operating the diesel reformer at low O/C ratio and/or, recirculation rat!o, is not realizable due to high probability of coke formation, whereas the second concept, combining a methanation process with CPOX, can provide a significant cool- ing effect in addition to the conventional c？oling concept which needs higher levels of excess air.
文摘By introducing the partial actions of primitive inverse semigroups on a set and their globalizations, a structure theorem for E^＊-unitary categorical inverse semigroups is obtained.
基金Project supported by the National Natural Science Foundation of China (No. 60971096)the National Basic Research Program (973) of China (No. 2006CB504100)
文摘Mental imagery generation is essential in the retrieval and storage of knowledge.Previous studies have indicated that the holistic properties of mental imagery generation can be evaluated more easily than the partial properties.However,the relationship between partial and holistic mental imagery generations has not been clearly demonstrated.To address this issue,we designed a task to investigate the changes in the spectrum of the electroencephalogram (EEG) during partial or holistic imagery generation.EEG signals were obtained from 18 healthy subjects,and a statistical measure of spectral dynamics between two EEG signals in per frequency band was performed.Additionally,a bicoherence spectrum analysis was used to detect the phase coupling within these two imagery conditions.Our results indicated that EEG of the partial imagery appeared earlier and stronger than that of the holistic imagery in the theta (5–8 Hz) range in a time window around 220 to 300 ms after cue onset,and a slight decrease in the alpha (8–12 Hz) band was observed at around 270 ms.The scalp topography of these changes in the theta and alpha bands distributed overall significantly in the frontal and central-temporal areas.The significant phase coupling within two conditions was remarkable at high frequency.From these results,we infer that there are complex relations between partial and holistic imageries.The generation of partial mental imagery is not a subprocess of holistic imagery,but it is relevant to holistic imagery and requires correct modification from the holistic information.
