A chromosome segment substitution line (CSSL) is a powerful tool for combining quantitative trait locus (QTL) mapping with the pyramiding of desirable alleles. The rice CSSL Z1364 with increased kernel number was iden...A chromosome segment substitution line (CSSL) is a powerful tool for combining quantitative trait locus (QTL) mapping with the pyramiding of desirable alleles. The rice CSSL Z1364 with increased kernel number was identified in a BC3F8 population derived from a cross of Nipponbare as the recipient with Xihui 18 as the donor parent. Z1364 carried three substitution segments distributed on chromosomes 1, 6, and 8. The mean substitution length was 1.19 Mb. Of 17 QTL identified on the substitution segments, qSP1 for spikelets per panicle, qSSD1 for seed-set density, and qNSB1 for number of secondary branches explained respectively 57.34%, 87.7%, and 49.44% of the corresponding phenotypic variance and were all linked to RM6777. Chi-square analysis showed that the increased kernel number in Z1364 was inherited recessively by a single gene. By fine mapping, qSP1 was delimited to a 50-kb region on the short arm of chromosome 1. Based on DNA sequence, a previously uncharacterized rice homolog of Arabidopsis thaliana AT4G32551 was identified as a candidate gene for qSP1 in which mutation increases the number of spikelets and kernels in Z1364. qSP1 was expressed in all tissues, but particularly in 1-cm panicles. The expression levels of OsMADS22, GN1A, and DST were upregulated and those of LAX2, GNP1, and GHD7 were downregulated in Nipponbare. These results provide a foundation for functional research on qSP1.展开更多
High-quality Mg-Nd-Zn-Zr magnesium alloy billets with diameter of 200 mm were successfully prepared by direct chill(DC)casting.The results show that microstructures of the as-cast billet prepared by DC casting are mai...High-quality Mg-Nd-Zn-Zr magnesium alloy billets with diameter of 200 mm were successfully prepared by direct chill(DC)casting.The results show that microstructures of the as-cast billet prepared by DC casting are mainly composed of equiaxed a-Mg and Mg 12 Nd eutectic compound distributing along the grain boundaries.The average grain size decreases along the radius of the billet.And the alloying elements of Nd and Zn distribute homogeneously across the large billet.The optimum process parameters for DC casting of the Mg-Nd-Zn-Zr magnesium alloy billet with diameter of 200 mm have been experimentally determined as follows:casting temperature 710℃ and casting speed 80 mm/min.展开更多
The spontaneous growth and evolution mechanism of metal whiskers have long been scientific problems.With the development of the integration of electronic and electrical productions,short circuits and system failures a...The spontaneous growth and evolution mechanism of metal whiskers have long been scientific problems.With the development of the integration of electronic and electrical productions,short circuits and system failures are raised by metal whiskers continuously.In the meantime,the related theories and mechanisms of whiskering problem are still vague,leading to a deficiency in the studies of environmental factors influencing the whisker phenomenon.Besides,the extreme environments such as aerospace,have been proven the accelerators to the formation of metal whiskers,resulting in a severe threaten to equipment and devices working in such environments including satellite and military equipment.To establish a comprehensive understanding to the whiskering process associated with their applicable control strategies,this study analyzes the growth phenomenon,influencing factors,formation process and evolution mechanism of metal whiskers in extreme service environments,puts forward the corresponding controlling strategies,offers a reference for the establishment of Chinese extreme aerospace strategic environment,and improves the reliability of aerospace systems.展开更多
Tdmercaptotriazine-functionalized polystyrene chelating resin was prepared and employed for the adsorption of Ag（I） from aqueous solution. The adsorbent was characterized according to the following techniques： Four...Tdmercaptotriazine-functionalized polystyrene chelating resin was prepared and employed for the adsorption of Ag（I） from aqueous solution. The adsorbent was characterized according to the following techniques： Fourier transform infrared spectroscopy, elemental analysis, scanning electron microscopy and the Brunauer-Emmet-Teller method. The effects of initial Ag（I） concentration, contact time, solution pH and coexisting ions on the adsorption capacity of Ag（I） were systematically investigated. The maximum adsorption capacity of AgO） was up to 187.1 mg/g resin at pH 0.0 and room temperature. The kinetic experiments indicated that the adsorption rate of Ag（I） onto the chelating resin was quite fast in the first 60 rain and reached adsorption equilibrium after 360 min. The adsorption process can be well described by the pseudo second-order kinetic model and the equilibrium adsorption isotherm was closely fitted by the Langmuir model. Moreover, the chelating resin could selectively adsorb more Ag（I） ions than other heavy metal ions including： Cu（Ⅱ）, Zn（Ⅱ）, Ni（Ⅱ）, Pb（Ⅱ） and Cr（Ⅲ） during competitive adsorption in the binary metal species systems, which indicated that it was a highly selective adsorbent of Ag（I） from aqueous solution.展开更多
The visible light photocatalytic H 2 evolution activities of a series of transition-metal substituted Keggin-structure heteropoly blues K 6 SiW 11 O 39 M(H 2 O)·nH 2 O (M=Co,Ni,Cu and Zn) were systematically stud...The visible light photocatalytic H 2 evolution activities of a series of transition-metal substituted Keggin-structure heteropoly blues K 6 SiW 11 O 39 M(H 2 O)·nH 2 O (M=Co,Ni,Cu and Zn) were systematically studied with Pt nanoparticles as co-catalyst.The H 2 evolution rates were 150,98,65 and 48 mol h-1g-1 for SiW 11 Cu,SiW 11 Ni,SiW 11 Co and SiW 11 Zn,respectively,meaning that the order of photocatalytic activity of these heteropoly blues from transition-metal substituted polyoxometalates was:SiW 11 Cu > SiW 11 Ni > SiW 11 Co > SiW 11 Zn.The catalysts could be efficiently reused for at least 5 cycles.展开更多
基金supported by the National Key Research Plan Project (2017YFD0101107)the Chongqing Science and Technology Commission Special Project (cstc2016shmsztzx0032)the Southwest University Innovation Team Project (XDJK2017A004)
文摘A chromosome segment substitution line (CSSL) is a powerful tool for combining quantitative trait locus (QTL) mapping with the pyramiding of desirable alleles. The rice CSSL Z1364 with increased kernel number was identified in a BC3F8 population derived from a cross of Nipponbare as the recipient with Xihui 18 as the donor parent. Z1364 carried three substitution segments distributed on chromosomes 1, 6, and 8. The mean substitution length was 1.19 Mb. Of 17 QTL identified on the substitution segments, qSP1 for spikelets per panicle, qSSD1 for seed-set density, and qNSB1 for number of secondary branches explained respectively 57.34%, 87.7%, and 49.44% of the corresponding phenotypic variance and were all linked to RM6777. Chi-square analysis showed that the increased kernel number in Z1364 was inherited recessively by a single gene. By fine mapping, qSP1 was delimited to a 50-kb region on the short arm of chromosome 1. Based on DNA sequence, a previously uncharacterized rice homolog of Arabidopsis thaliana AT4G32551 was identified as a candidate gene for qSP1 in which mutation increases the number of spikelets and kernels in Z1364. qSP1 was expressed in all tissues, but particularly in 1-cm panicles. The expression levels of OsMADS22, GN1A, and DST were upregulated and those of LAX2, GNP1, and GHD7 were downregulated in Nipponbare. These results provide a foundation for functional research on qSP1.
基金supported by National Natural Science Foundation of China(Grant No.51775329 and 51605280)the Foundation of Shanghai youth teacher training scheme(Grant No.ZZSHOU16016)the Doctoral Scientific Re-search Foundation of Shanghai Ocean University(Grant No.A2-0203-17-100325).
文摘High-quality Mg-Nd-Zn-Zr magnesium alloy billets with diameter of 200 mm were successfully prepared by direct chill(DC)casting.The results show that microstructures of the as-cast billet prepared by DC casting are mainly composed of equiaxed a-Mg and Mg 12 Nd eutectic compound distributing along the grain boundaries.The average grain size decreases along the radius of the billet.And the alloying elements of Nd and Zn distribute homogeneously across the large billet.The optimum process parameters for DC casting of the Mg-Nd-Zn-Zr magnesium alloy billet with diameter of 200 mm have been experimentally determined as follows:casting temperature 710℃ and casting speed 80 mm/min.
基金supported by the National Natural Science Foundation of China(No.41976194).
文摘The spontaneous growth and evolution mechanism of metal whiskers have long been scientific problems.With the development of the integration of electronic and electrical productions,short circuits and system failures are raised by metal whiskers continuously.In the meantime,the related theories and mechanisms of whiskering problem are still vague,leading to a deficiency in the studies of environmental factors influencing the whisker phenomenon.Besides,the extreme environments such as aerospace,have been proven the accelerators to the formation of metal whiskers,resulting in a severe threaten to equipment and devices working in such environments including satellite and military equipment.To establish a comprehensive understanding to the whiskering process associated with their applicable control strategies,this study analyzes the growth phenomenon,influencing factors,formation process and evolution mechanism of metal whiskers in extreme service environments,puts forward the corresponding controlling strategies,offers a reference for the establishment of Chinese extreme aerospace strategic environment,and improves the reliability of aerospace systems.
基金supported by the Chinese Academy of Science and Technology Project in Support of Gansu (No.XBLZ-2011-013)
文摘Tdmercaptotriazine-functionalized polystyrene chelating resin was prepared and employed for the adsorption of Ag（I） from aqueous solution. The adsorbent was characterized according to the following techniques： Fourier transform infrared spectroscopy, elemental analysis, scanning electron microscopy and the Brunauer-Emmet-Teller method. The effects of initial Ag（I） concentration, contact time, solution pH and coexisting ions on the adsorption capacity of Ag（I） were systematically investigated. The maximum adsorption capacity of AgO） was up to 187.1 mg/g resin at pH 0.0 and room temperature. The kinetic experiments indicated that the adsorption rate of Ag（I） onto the chelating resin was quite fast in the first 60 rain and reached adsorption equilibrium after 360 min. The adsorption process can be well described by the pseudo second-order kinetic model and the equilibrium adsorption isotherm was closely fitted by the Langmuir model. Moreover, the chelating resin could selectively adsorb more Ag（I） ions than other heavy metal ions including： Cu（Ⅱ）, Zn（Ⅱ）, Ni（Ⅱ）, Pb（Ⅱ） and Cr（Ⅲ） during competitive adsorption in the binary metal species systems, which indicated that it was a highly selective adsorbent of Ag（I） from aqueous solution.
基金supported by the National Natural Science Foundation of China(91027002)the Special Fund from the Central Collegiate Basic Scientific Research Bursary+2 种基金the Postdoctoral Station Foundation of Ministry of Education(20060200002)the Testing Foundation of Northeast Normal University(NENU)the Program for Chang jiang Scholars and Innovative Research Team in University
文摘The visible light photocatalytic H 2 evolution activities of a series of transition-metal substituted Keggin-structure heteropoly blues K 6 SiW 11 O 39 M(H 2 O)·nH 2 O (M=Co,Ni,Cu and Zn) were systematically studied with Pt nanoparticles as co-catalyst.The H 2 evolution rates were 150,98,65 and 48 mol h-1g-1 for SiW 11 Cu,SiW 11 Ni,SiW 11 Co and SiW 11 Zn,respectively,meaning that the order of photocatalytic activity of these heteropoly blues from transition-metal substituted polyoxometalates was:SiW 11 Cu > SiW 11 Ni > SiW 11 Co > SiW 11 Zn.The catalysts could be efficiently reused for at least 5 cycles.
