Oxy-steam combustion is a promising next-generation combustion technology.Conversions of fuel-N,volatile-N,and char-N to NO and N_2O during combustion of a single coal particle in O_2/N_2and O_2/H_2O were studied in a...Oxy-steam combustion is a promising next-generation combustion technology.Conversions of fuel-N,volatile-N,and char-N to NO and N_2O during combustion of a single coal particle in O_2/N_2and O_2/H_2O were studied in a tube reactor at low temperature.In O_2/N_2,NO reaches the maximum value in the devolatilization stage and N_2O reaches the maximum value in the char combustion stage.In O_2/H_2O,both NO and N_2O reach the maximum values in the char combustion stage.The total conversion ratios of fuel-N to NO and N_2O in O_2/N_2are obviously higher than those in O_2/H_2O,due to the reduction of H_2O on NO and N_2O.Temperature changes the trade-off between NO and N_2O.In O_2/N_2and O_2/H_2O,the conversion ratios of fuel-N,volatile-N,and char-N to NO increase with increasing temperature,and those to N_2O show the opposite trends.The conversion ratios of fuel-N,volatile-N,and char-N to NO reach the maximum values at b O_2N=30 vol%in O_2/N_2.In O_2/H_2O,the conversion ratios of fuel-N and char-N to NO reach the maximum values at b O_2N=30 vol%,and the conversion ratio of volatile-N to NO shows a slightly increasing trend with increasing oxygen concentration.The conversion ratios of fuel-N,volatile-N,and char-N to N_2O decrease with increasing oxygen concentration in both atmospheres.A higher coal rank has higher conversion ratios of fuel-N to NO and N_2O.Anthracite coal exhibits the highest conversion ratios of fuel-N,volatile-N,and char-N to NO and N_2O in both atmospheres.This work is to develop efficient ways to understand and control NO and N_2O emissions for a clean and sustainable atmosphere.展开更多
为了考察发状念珠藻(发菜)在类火星表面半开放体系复苏的可行性,搭建了在线监测模拟类火星环境密闭体系内发菜复苏时放氧速率的试验装置,并考察了水对发菜光合放氧复苏的影响。结果显示,在气压超过5℃、15℃、25℃所对应的水饱和蒸气压...为了考察发状念珠藻(发菜)在类火星表面半开放体系复苏的可行性,搭建了在线监测模拟类火星环境密闭体系内发菜复苏时放氧速率的试验装置,并考察了水对发菜光合放氧复苏的影响。结果显示,在气压超过5℃、15℃、25℃所对应的水饱和蒸气压时,发菜放氧最高速率分别为5、7和10μmol O_2·h^(-1)·g^(-1)(DW),分别是发菜最大放氧速率的1%、2%和3%;而在气压低于相应的水饱和蒸气压时,发菜放氧平均速率分别下降为1、2和3μmol O_2·h^(-1)·g^(-1)(DW),且随着反应时间的延长,发菜在5℃放氧速率下降为0;然而,在5℃,气压为1.7~1.9 k Pa,加入10 mL BG11时,发菜放氧速率最高上调至12μmol O_2·h^(-1)·g^(-1)(DW)。以上结果显示,水对发菜在类火星表面半开放体系复苏的影响大于气压。展开更多
Manufacturing and integration of micro-electro-mechanical systems(MEMS) devices and integrated circuits(ICs) by wafer bonding often generate problems caused by thermal properties of materials.This paper presents a low...Manufacturing and integration of micro-electro-mechanical systems(MEMS) devices and integrated circuits(ICs) by wafer bonding often generate problems caused by thermal properties of materials.This paper presents a low temperature wafer direct bonding process assisted by O2 plasma.Silicon wafers were treated with wet chemical cleaning and subsequently activated by O2 plasma in the etch element of a sputtering system.Then,two wafers were brought into contact in the bonder followed by annealing in N2 atmosphere for several hours.An infrared imaging system was used to detect bonding defects and a razor blade test was carried out to determine surface energy.The bonding yield reaches 90%-95% and the achieved surface energy is 1.76 J/m2 when the bonded wafers are annealed at 350 ℃ in N2 atmosphere for 2 h.Void formation was systematically observed and elimination methods were proposed.The size and density of voids greatly depend on the annealing temperature.Short O2 plasma treatment for 60 s can alleviate void formation and enhance surface energy.A pulling test reveals that the bonding strength is more than 11.0 MPa.This low temperature wafer direct bonding process provides an efficient and reliable method for 3D integration,system on chip,and MEMS packaging.展开更多
基金Supported by the National Basic Research Program of China(2015CB251501)the Innovative Research Groups of the National Natural Science Foundation of China(51621005)
文摘Oxy-steam combustion is a promising next-generation combustion technology.Conversions of fuel-N,volatile-N,and char-N to NO and N_2O during combustion of a single coal particle in O_2/N_2and O_2/H_2O were studied in a tube reactor at low temperature.In O_2/N_2,NO reaches the maximum value in the devolatilization stage and N_2O reaches the maximum value in the char combustion stage.In O_2/H_2O,both NO and N_2O reach the maximum values in the char combustion stage.The total conversion ratios of fuel-N to NO and N_2O in O_2/N_2are obviously higher than those in O_2/H_2O,due to the reduction of H_2O on NO and N_2O.Temperature changes the trade-off between NO and N_2O.In O_2/N_2and O_2/H_2O,the conversion ratios of fuel-N,volatile-N,and char-N to NO increase with increasing temperature,and those to N_2O show the opposite trends.The conversion ratios of fuel-N,volatile-N,and char-N to NO reach the maximum values at b O_2N=30 vol%in O_2/N_2.In O_2/H_2O,the conversion ratios of fuel-N and char-N to NO reach the maximum values at b O_2N=30 vol%,and the conversion ratio of volatile-N to NO shows a slightly increasing trend with increasing oxygen concentration.The conversion ratios of fuel-N,volatile-N,and char-N to N_2O decrease with increasing oxygen concentration in both atmospheres.A higher coal rank has higher conversion ratios of fuel-N to NO and N_2O.Anthracite coal exhibits the highest conversion ratios of fuel-N,volatile-N,and char-N to NO and N_2O in both atmospheres.This work is to develop efficient ways to understand and control NO and N_2O emissions for a clean and sustainable atmosphere.
文摘为了考察发状念珠藻(发菜)在类火星表面半开放体系复苏的可行性,搭建了在线监测模拟类火星环境密闭体系内发菜复苏时放氧速率的试验装置,并考察了水对发菜光合放氧复苏的影响。结果显示,在气压超过5℃、15℃、25℃所对应的水饱和蒸气压时,发菜放氧最高速率分别为5、7和10μmol O_2·h^(-1)·g^(-1)(DW),分别是发菜最大放氧速率的1%、2%和3%;而在气压低于相应的水饱和蒸气压时,发菜放氧平均速率分别下降为1、2和3μmol O_2·h^(-1)·g^(-1)(DW),且随着反应时间的延长,发菜在5℃放氧速率下降为0;然而,在5℃,气压为1.7~1.9 k Pa,加入10 mL BG11时,发菜放氧速率最高上调至12μmol O_2·h^(-1)·g^(-1)(DW)。以上结果显示,水对发菜在类火星表面半开放体系复苏的影响大于气压。
基金Project supported by the Foreign Cultural and Educational Experts Employing Plan,Ministry of Education,China (No. TS2010CQDX 056)the Fundamental Research Funds for the Central Universi-ties,China (No. CDJZR12135502)
文摘Manufacturing and integration of micro-electro-mechanical systems(MEMS) devices and integrated circuits(ICs) by wafer bonding often generate problems caused by thermal properties of materials.This paper presents a low temperature wafer direct bonding process assisted by O2 plasma.Silicon wafers were treated with wet chemical cleaning and subsequently activated by O2 plasma in the etch element of a sputtering system.Then,two wafers were brought into contact in the bonder followed by annealing in N2 atmosphere for several hours.An infrared imaging system was used to detect bonding defects and a razor blade test was carried out to determine surface energy.The bonding yield reaches 90%-95% and the achieved surface energy is 1.76 J/m2 when the bonded wafers are annealed at 350 ℃ in N2 atmosphere for 2 h.Void formation was systematically observed and elimination methods were proposed.The size and density of voids greatly depend on the annealing temperature.Short O2 plasma treatment for 60 s can alleviate void formation and enhance surface energy.A pulling test reveals that the bonding strength is more than 11.0 MPa.This low temperature wafer direct bonding process provides an efficient and reliable method for 3D integration,system on chip,and MEMS packaging.
