Activity 1.Think about the following questions and write down your answers before reading the text.1.Have you ever tried Liuzhou Luosifen?If so,what did you think of it?2.What makes Liuzhou Luosifen unique compared to...Activity 1.Think about the following questions and write down your answers before reading the text.1.Have you ever tried Liuzhou Luosifen?If so,what did you think of it?2.What makes Liuzhou Luosifen unique compared to other types of noodles?展开更多
因其速率快、稳定性高,非金属N与金属共掺杂的碳材料作为新型高效ORR催化剂而引起了人们的广泛关注.采用包含色散力校正的密度泛函理论方法系统地研究了氧分子在FeN_4掺杂的碳纳米管上的吸附、氢化特性.结果表明:(1)O_2倾向于以end-on...因其速率快、稳定性高,非金属N与金属共掺杂的碳材料作为新型高效ORR催化剂而引起了人们的广泛关注.采用包含色散力校正的密度泛函理论方法系统地研究了氧分子在FeN_4掺杂的碳纳米管上的吸附、氢化特性.结果表明:(1)O_2倾向于以end-on模式吸附在Fe顶位,O-O键与衬底表面成一定角度,并指向五元环,对应的吸附能为1.62 e V.(2)O_2在FeN_4-CNTs上更倾向于直接氢化为OOH,然后解离为O+OH,整个路径的限速步为OOH的解离,对应的势垒为1.19 eV.展开更多
因其较好的稳定性和催化活性,非金属N与金属共掺杂的富勒烯(C60)作为新型氧化还原反应(ORR)催化剂受到了人们的广泛关注.采用基于密度泛函理论的第一性原理方法系统地研究了Fe N4掺杂对C60催化特性的调制规律,揭示了O_2在Fe N4掺杂的C6...因其较好的稳定性和催化活性,非金属N与金属共掺杂的富勒烯(C60)作为新型氧化还原反应(ORR)催化剂受到了人们的广泛关注.采用基于密度泛函理论的第一性原理方法系统地研究了Fe N4掺杂对C60催化特性的调制规律,揭示了O_2在Fe N4掺杂的C60上的吸附和氢化特性.结果表明:(1)O_2倾向于以side-on模式吸附在Fe的顶位上,O-O键平行于C60的球切面,与Fe形成O-Fe-O三元环结构,对应的吸附能为1.48 e V.(2)O_2的氢化反应路径可以分为两条:(i)O_2先解离为O+O,然后氢化为O+OH.O_2的解离为反应的速控步,势垒为2.82 e V.(ii)O_2先氢化形成OOH结构,然后解离.氢化为反应的速控步,势垒为2.83 e V.展开更多
采用热解法制备FeN/C催化剂,考察催化剂前驱体中氮含量对其氧还原活性的影响.使用X射线衍射、比表面积和孔径分布测试、透射电子显微镜以及热重分析等方法对催化剂的结构、形貌及催化剂前驱体的热性质等进行表征,使用线性扫描伏安法对...采用热解法制备FeN/C催化剂,考察催化剂前驱体中氮含量对其氧还原活性的影响.使用X射线衍射、比表面积和孔径分布测试、透射电子显微镜以及热重分析等方法对催化剂的结构、形貌及催化剂前驱体的热性质等进行表征,使用线性扫描伏安法对催化剂的氧还原活性进行测试.结果表明,以1,10-菲啰啉为氮源,FeCl3为铁源,Black Pearl 2000为载体,催化剂前驱体中1,10-菲啰啉含量为20wt%,Fe含量为1wt%时,热处理制备所得催化剂粒子分布均匀,比表面积为824.48 m2·g-1,平均孔隙为10.58 nm,表面的氮元素含量为0.31wt%;并具有最好的氧还原催化活性.催化剂前驱体中氮源含量在热解过程中导致催化剂的比表面积、孔径结构及表面氮元素含量的变化是影响催化剂活性的关键因素.展开更多
在前期FeN/C催化剂研究的基础上,以不同的含硫化合物为硫源,在Ar气氛下高温热处理获得一系列FeNS/C催化剂。使用线性扫描伏安法测试催化剂的氧还原活性,通过热重分析、比表面积和孔径分布测试对催化剂前驱体的热性质及催化剂的结构等进...在前期FeN/C催化剂研究的基础上,以不同的含硫化合物为硫源,在Ar气氛下高温热处理获得一系列FeNS/C催化剂。使用线性扫描伏安法测试催化剂的氧还原活性,通过热重分析、比表面积和孔径分布测试对催化剂前驱体的热性质及催化剂的结构等进行表征。结果表明,分别以硫脲为硫源,1,10-菲啰啉为氮源,FeCl_3为铁源,Black Pearl 2000为载体,催化剂前驱体中硫含量为1wt.%时,所得催化剂比表面积为559. 39 m^2/g,且催化剂表现出较好的氧还原催化活性。硫源的种类、热性质对催化剂的氧还原活性有着明显影响。展开更多
The resistance in tomato plants to bacterial speck caused by Pseudomonas syringae pv. tomato is triggered by the interactions between the plant resistance protein Pto and the pathogen avirulence proteins AvrPto or Avr...The resistance in tomato plants to bacterial speck caused by Pseudomonas syringae pv. tomato is triggered by the interactions between the plant resistance protein Pto and the pathogen avirulence proteins AvrPto or AvrPtoB. Fen is a gene encoding closely related functional protein kinases as the Pto gene. To investigate the status of resistance to the pathogen and natural variation of Pto and Fen genes in tomato, 67 lines including 29 growing in China were subject to disease resistance evaluation and fenthion-sensitivity test. Alleles of Pto and Fen were amplified from genomic DNA of 25 tomato lines using polymerase chain reaction （PCR） and sequences were determined by sequencing the PCR products. The results indicated that none of the 29 cultivars/hybrids growing in China were resistant to bacterial speck race 0 strain DC3000. Seven of eight tomato lines resistant to DC3000 were also fenthion-sensitive. Analysis of deduced amino acid sequences identified three novel residue substitutions between Pto and pto, and one new substitution identified between Fen and fen. A PCR-based marker was developed and successfully used to select plants with resistance to DC3000.展开更多
文摘Activity 1.Think about the following questions and write down your answers before reading the text.1.Have you ever tried Liuzhou Luosifen?If so,what did you think of it?2.What makes Liuzhou Luosifen unique compared to other types of noodles?
文摘因其速率快、稳定性高,非金属N与金属共掺杂的碳材料作为新型高效ORR催化剂而引起了人们的广泛关注.采用包含色散力校正的密度泛函理论方法系统地研究了氧分子在FeN_4掺杂的碳纳米管上的吸附、氢化特性.结果表明:(1)O_2倾向于以end-on模式吸附在Fe顶位,O-O键与衬底表面成一定角度,并指向五元环,对应的吸附能为1.62 e V.(2)O_2在FeN_4-CNTs上更倾向于直接氢化为OOH,然后解离为O+OH,整个路径的限速步为OOH的解离,对应的势垒为1.19 eV.
文摘因其较好的稳定性和催化活性,非金属N与金属共掺杂的富勒烯(C60)作为新型氧化还原反应(ORR)催化剂受到了人们的广泛关注.采用基于密度泛函理论的第一性原理方法系统地研究了Fe N4掺杂对C60催化特性的调制规律,揭示了O_2在Fe N4掺杂的C60上的吸附和氢化特性.结果表明:(1)O_2倾向于以side-on模式吸附在Fe的顶位上,O-O键平行于C60的球切面,与Fe形成O-Fe-O三元环结构,对应的吸附能为1.48 e V.(2)O_2的氢化反应路径可以分为两条:(i)O_2先解离为O+O,然后氢化为O+OH.O_2的解离为反应的速控步,势垒为2.82 e V.(ii)O_2先氢化形成OOH结构,然后解离.氢化为反应的速控步,势垒为2.83 e V.
文摘采用热解法制备FeN/C催化剂,考察催化剂前驱体中氮含量对其氧还原活性的影响.使用X射线衍射、比表面积和孔径分布测试、透射电子显微镜以及热重分析等方法对催化剂的结构、形貌及催化剂前驱体的热性质等进行表征,使用线性扫描伏安法对催化剂的氧还原活性进行测试.结果表明,以1,10-菲啰啉为氮源,FeCl3为铁源,Black Pearl 2000为载体,催化剂前驱体中1,10-菲啰啉含量为20wt%,Fe含量为1wt%时,热处理制备所得催化剂粒子分布均匀,比表面积为824.48 m2·g-1,平均孔隙为10.58 nm,表面的氮元素含量为0.31wt%;并具有最好的氧还原催化活性.催化剂前驱体中氮源含量在热解过程中导致催化剂的比表面积、孔径结构及表面氮元素含量的变化是影响催化剂活性的关键因素.
文摘在前期FeN/C催化剂研究的基础上,以不同的含硫化合物为硫源,在Ar气氛下高温热处理获得一系列FeNS/C催化剂。使用线性扫描伏安法测试催化剂的氧还原活性,通过热重分析、比表面积和孔径分布测试对催化剂前驱体的热性质及催化剂的结构等进行表征。结果表明,分别以硫脲为硫源,1,10-菲啰啉为氮源,FeCl_3为铁源,Black Pearl 2000为载体,催化剂前驱体中硫含量为1wt.%时,所得催化剂比表面积为559. 39 m^2/g,且催化剂表现出较好的氧还原催化活性。硫源的种类、热性质对催化剂的氧还原活性有着明显影响。
基金supported by the National High Technology Research and Development Program of China (2006AA10Z1A6)the Program for New Century Excellent Talents in University, China (NCET-08-0531)
文摘The resistance in tomato plants to bacterial speck caused by Pseudomonas syringae pv. tomato is triggered by the interactions between the plant resistance protein Pto and the pathogen avirulence proteins AvrPto or AvrPtoB. Fen is a gene encoding closely related functional protein kinases as the Pto gene. To investigate the status of resistance to the pathogen and natural variation of Pto and Fen genes in tomato, 67 lines including 29 growing in China were subject to disease resistance evaluation and fenthion-sensitivity test. Alleles of Pto and Fen were amplified from genomic DNA of 25 tomato lines using polymerase chain reaction （PCR） and sequences were determined by sequencing the PCR products. The results indicated that none of the 29 cultivars/hybrids growing in China were resistant to bacterial speck race 0 strain DC3000. Seven of eight tomato lines resistant to DC3000 were also fenthion-sensitive. Analysis of deduced amino acid sequences identified three novel residue substitutions between Pto and pto, and one new substitution identified between Fen and fen. A PCR-based marker was developed and successfully used to select plants with resistance to DC3000.
