Tl2Ba2Ca2Cu3O10 was reported to be a superconductor with a highest transition temperature of 125 K among the homologous series of Tl2Ba2Can-1CunO2n＋4. The direct information on the Cu ion site at the atomic level is ...Tl2Ba2Ca2Cu3O10 was reported to be a superconductor with a highest transition temperature of 125 K among the homologous series of Tl2Ba2Can-1CunO2n＋4. The direct information on the Cu ion site at the atomic level is important for elucidating the superconductivity mechanism. The local bond properties of Tl2Ba2Ca2Cu3O10 were studied using the average band-gap model. The calculated results show that the covalency of Cu（1）-O bond is 0.561, and the average covalency of Cu（2）-O is 0.296. Mossbauer isomer shifts of 57Fe in Tl2Ba2Ca2Cu3O10 were calculated using the chemical surrounding factor, defined by covalency and electronic polarizability. It is verified that for lower doping, Fe substitute the Cu at the Cu （1） site in forms of Fe^3＋ and Fe^4＋; for higher doping, Fe^3＋ and Fe^4＋ ion occupies Cu（1） and Cu（2） site respectively. The studies show that the determination of the correspondence between spectrum components and actual copper sites occupied by MSssbauer nucleus was made easier with the aid of the calculation results of the chemical bond parameters.展开更多
[目的]获得苏云金芽胞杆菌QL32-1中杀虫晶体蛋白基因,并分析其杀虫活性。[方法]采用cyt基因通用引物、两步法染色体步移的方法对QL32-1中cyt基因进行鉴定和全长克隆,再构建重组质粒pET-28a-2Ba16,并转化到大肠杆菌BL21(DE3)中,经IPTG诱...[目的]获得苏云金芽胞杆菌QL32-1中杀虫晶体蛋白基因,并分析其杀虫活性。[方法]采用cyt基因通用引物、两步法染色体步移的方法对QL32-1中cyt基因进行鉴定和全长克隆,再构建重组质粒pET-28a-2Ba16,并转化到大肠杆菌BL21(DE3)中,经IPTG诱导表达,最后对表达蛋白进行杀虫活性分析。[结果]克隆得到1个全长783 bp cyt2B基因,其编码260个氨基酸,推导分子量约29.69 kDa,此氨基酸序列与已知的Cyt2Ba1蛋白同源性最高,为92.4%。该基因被国际杀虫晶体蛋白基因命名委员会正式命名为cyt2Ba16。杀虫活性分析表明:cyt2Ba16对双翅目的库蚊(Culex quinquefasciatus)具有显著的杀虫活性,LC50为9.73μg/mL。[结论]cyt2Ba16基因是一个对库蚊具有较高杀虫活性的新型cyt基因,为QL32-1菌株的应用提供理论基础。展开更多
K2Ba（MoO4）2：Eu3＋ phosphors were synthesized by solid-state reaction. The emission and excitation spectra of K2 Ba（MoO4）2：Eu3＋ phosphors exhibited that the phosphors could be effectively excited by near ultravi...K2Ba（MoO4）2：Eu3＋ phosphors were synthesized by solid-state reaction. The emission and excitation spectra of K2 Ba（MoO4）2：Eu3＋ phosphors exhibited that the phosphors could be effectively excited by near ultraviolet （394 nm） and blue （465 nm） light, and emitted red light at 616 nm. The influence of Eu3＋concentration, sintering temperature and charge compensators （K＋, Na＋ or Li＋ ） on the emission intensity were investigated. The results indicated that concentration quenching of Eu3＋ was not observed within 30mol.% Eu 3＋, 600 oC was a suitable sintering temperature for preparation of K2 Ba（MoO4）2：Eu3＋phosphors, and K＋ ions gave the best improvement to enhance the emission intensity. The CIE chromaticity coordinates of K2 Ba（MoO4）2：0.05Eu3＋phosphor were calculated to be （0.68, 0.32）, and color purity was 97.4%.展开更多
Cu-substituted Bi2Ba2Co2-xCuxOy（0.0≤x≤0.4） samples were prepared by conventional solid-state reaction method and the effect of Cu substitution on the microstructure and thermoelectric properties were investigated....Cu-substituted Bi2Ba2Co2-xCuxOy（0.0≤x≤0.4） samples were prepared by conventional solid-state reaction method and the effect of Cu substitution on the microstructure and thermoelectric properties were investigated.The partial substitution of Cu for Co in Bi2Ba2Co2-xCuxOy led to an increase in the electrical conductivity because of an increase in the hole concentration and grain size of sintered bodies.In addition,Cu substitution led to an increase in Seebeck coefficients while kept the thermal conductivity unchanged.The highest thermoelectric figure of merit（ZT value） was obtained in x=0.4 sample and the value was 1.5 times as large as that of Cu-free sample at 873 K.展开更多
The top-seeded infiltration and growth process (TSIG) is an important method to fabricate YBCO bulk superconductors. In this paper, single domain YBCO superconductors with different Gd2Ba4CuWOx (GdW2411) additions hav...The top-seeded infiltration and growth process (TSIG) is an important method to fabricate YBCO bulk superconductors. In this paper, single domain YBCO superconductors with different Gd2Ba4CuWOx (GdW2411) additions have been fabricated by TSIG process, the amount of GdW2411 added to Y2BaCuO5 (Y211) is in the range from 0wt% to 8 wt%, but there is no other additions to the liquid source. The growth morphology, microstructure and levitation force of the YBCO bulks have been investigated, it is found that the levitation force is increasing from 14 to 25 N with the increasing of GdW2411 addition from 0 to 4 wt%, and decreasing from 25 to 7 N with the increasing of GdW2411 addition from 4 to 8 wt%, the largest levitation force is obtained when the GdW2411 content is about 4 wt%. This is helpful for the fabrication of high quality YBCO bulk superconductors.展开更多
文摘Tl2Ba2Ca2Cu3O10 was reported to be a superconductor with a highest transition temperature of 125 K among the homologous series of Tl2Ba2Can-1CunO2n＋4. The direct information on the Cu ion site at the atomic level is important for elucidating the superconductivity mechanism. The local bond properties of Tl2Ba2Ca2Cu3O10 were studied using the average band-gap model. The calculated results show that the covalency of Cu（1）-O bond is 0.561, and the average covalency of Cu（2）-O is 0.296. Mossbauer isomer shifts of 57Fe in Tl2Ba2Ca2Cu3O10 were calculated using the chemical surrounding factor, defined by covalency and electronic polarizability. It is verified that for lower doping, Fe substitute the Cu at the Cu （1） site in forms of Fe^3＋ and Fe^4＋; for higher doping, Fe^3＋ and Fe^4＋ ion occupies Cu（1） and Cu（2） site respectively. The studies show that the determination of the correspondence between spectrum components and actual copper sites occupied by MSssbauer nucleus was made easier with the aid of the calculation results of the chemical bond parameters.
文摘[目的]获得苏云金芽胞杆菌QL32-1中杀虫晶体蛋白基因,并分析其杀虫活性。[方法]采用cyt基因通用引物、两步法染色体步移的方法对QL32-1中cyt基因进行鉴定和全长克隆,再构建重组质粒pET-28a-2Ba16,并转化到大肠杆菌BL21(DE3)中,经IPTG诱导表达,最后对表达蛋白进行杀虫活性分析。[结果]克隆得到1个全长783 bp cyt2B基因,其编码260个氨基酸,推导分子量约29.69 kDa,此氨基酸序列与已知的Cyt2Ba1蛋白同源性最高,为92.4%。该基因被国际杀虫晶体蛋白基因命名委员会正式命名为cyt2Ba16。杀虫活性分析表明:cyt2Ba16对双翅目的库蚊(Culex quinquefasciatus)具有显著的杀虫活性,LC50为9.73μg/mL。[结论]cyt2Ba16基因是一个对库蚊具有较高杀虫活性的新型cyt基因,为QL32-1菌株的应用提供理论基础。
基金Project supported by Natural Science Foundation of Fujian Province (2011J033)
文摘K2Ba（MoO4）2：Eu3＋ phosphors were synthesized by solid-state reaction. The emission and excitation spectra of K2 Ba（MoO4）2：Eu3＋ phosphors exhibited that the phosphors could be effectively excited by near ultraviolet （394 nm） and blue （465 nm） light, and emitted red light at 616 nm. The influence of Eu3＋concentration, sintering temperature and charge compensators （K＋, Na＋ or Li＋ ） on the emission intensity were investigated. The results indicated that concentration quenching of Eu3＋ was not observed within 30mol.% Eu 3＋, 600 oC was a suitable sintering temperature for preparation of K2 Ba（MoO4）2：Eu3＋phosphors, and K＋ ions gave the best improvement to enhance the emission intensity. The CIE chromaticity coordinates of K2 Ba（MoO4）2：0.05Eu3＋phosphor were calculated to be （0.68, 0.32）, and color purity was 97.4%.
基金supported by the Foundation for University Key Teacher of Henan Province,China(No. 2008136)the Program for Innovative Research Team (in Science and Technology) in Henan Institute of Engineering(No.2009IRTHNIE05)
文摘Cu-substituted Bi2Ba2Co2-xCuxOy（0.0≤x≤0.4） samples were prepared by conventional solid-state reaction method and the effect of Cu substitution on the microstructure and thermoelectric properties were investigated.The partial substitution of Cu for Co in Bi2Ba2Co2-xCuxOy led to an increase in the electrical conductivity because of an increase in the hole concentration and grain size of sintered bodies.In addition,Cu substitution led to an increase in Seebeck coefficients while kept the thermal conductivity unchanged.The highest thermoelectric figure of merit（ZT value） was obtained in x=0.4 sample and the value was 1.5 times as large as that of Cu-free sample at 873 K.
基金National Natural Science Foundation of China (50872079)National High Technology Research and Development Program of China ("863"2007AA03Z241)Fundamental Research Funds for the Central Universities (GK200901017)
文摘The top-seeded infiltration and growth process (TSIG) is an important method to fabricate YBCO bulk superconductors. In this paper, single domain YBCO superconductors with different Gd2Ba4CuWOx (GdW2411) additions have been fabricated by TSIG process, the amount of GdW2411 added to Y2BaCuO5 (Y211) is in the range from 0wt% to 8 wt%, but there is no other additions to the liquid source. The growth morphology, microstructure and levitation force of the YBCO bulks have been investigated, it is found that the levitation force is increasing from 14 to 25 N with the increasing of GdW2411 addition from 0 to 4 wt%, and decreasing from 25 to 7 N with the increasing of GdW2411 addition from 4 to 8 wt%, the largest levitation force is obtained when the GdW2411 content is about 4 wt%. This is helpful for the fabrication of high quality YBCO bulk superconductors.
