排序方式: 共有12条查询结果,搜索用时 140 毫秒
1.
Wei Hu Jian-zhang Li Ying Wang Shen-xin Li Jia-qing Xie 《Journal of Dispersion Science and Technology》2013,34(1):88-95
Metallomicelles made from two Schiff base manganese(III) complexes (MnL1 and MnL2) and surfactants (CTAB and Brij35) were used as mimetic peroxidase in the catalytic oxidation of phenol by H2O2. The catalytic activity of the complexes (MnL1 and MnL2) were investigated. The mechanism and a kinetic mathematic model of the phenol catalytic oxidation were also studied. The results show the optimum acidity of the enzyme-like system in the paper is ca. pH 7.0, the optimum temperature which is ca. 35°C and the optimum molar ratio of H2O2 to the complex is ca. 30 in the complexes-H2O2-buffered solution; the Schiff base manganese(III) complexes and their metallomicelles as peroxidase mimics exhibit good catalytic activity and similar catalytic character to natural enzyme. 相似文献
2.
新一代白光LED照明用一种适于近紫外光激发的单一白光荧光粉 总被引:42,自引:8,他引:34
首次报道单一Sr2MgSiO5:Eu^2 材料的白光发射性质。发射光谱由两个谱带组成,分别位于470,570nm处,并具有不同的荧光寿命,归结为处于不同格位上的二价铕离子的发射,它们混合成白光。这两个发射带所对应的激发光谱均分布在250~450nm的紫外区,利用该荧光粉和具有400nm近紫外光发射的InGaN管芯制成了白光LED。正向驱动电流为20mA时,色温为5664K;发光色坐标为x=0.33,y=0.34;显色指数为85%;光强达8100cd/m^2。实验表明,器件的色坐标和显色指数等参数随正向驱动电流的变化起伏量小于5%,优于目前商用的蓝光管芯泵浦白光LED,报道的单一白光荧光粉在新一代白光LED照明领域具有广阔的应用前景。 相似文献
3.
给出了稀土离子电子态在高静水压下的某些特性,包括高压下的发光光 谱及能级特性,晶体场强度的压力效应,4f电子库仑排斥及自旋轨道耦合等作用随压力 的变化等。 相似文献
4.
Jian-zhang Li Shen-xin Li Feng Xie Bo Zhou Wei Zeng Sheng-ying Qin 《Transition Metal Chemistry》2006,31(8):1066-1070
Mono-Schiff base CoII complexes, CoL
2
1
–CoL
2
6
with aza-crown or morpholino pendants were synthesized. The O2 uptake of these complexes in MeOCH2CH2OMe solution was determined at different temperatures, and the equilibrium constants (KO2) and thermodynamic parameters (ΔH
0, ΔS
0) for oxygenation were calculated. The corresponding MnIII complexes, MnL
2
1
Cl–MnL
2
6
Cl, were employed to catalyze epoxidation of styrene at ambient temperature and pressures. Crown ether effects on the modulation
of O2-binding capability and the catalytic oxidation of styrene are discussed. The results indicate that the dioxygen affinities
of the CoII complexes are much more enhanced by aza-crown pendants than that by morpholino pendants, and the O2-binding capabilities of CoL
2
1
–CoL
2
3
with aza-crown pendants can also be enhanced by adding alkali metal (Li+, Na+ and K+) cations; similarly, the catalytic activities of the MnIII complexes with aza-crown pendants, MnL
2
1
Cl–MnL
2
3
Cl, are higher than those of the MnIII complexes with morpholino pendants, MnL
2
4
Cl–MnL
2
6
Cl. 相似文献
5.
A Kinetic Study of Phenolic Oxidation by H2O2 Using the Schiff Base Complexes As Mimetic Peroxidases
Xie Jia-qing Li Jian-zhang Meng Xiang-guang Hu Chang-wei Zeng Xian-cheng Li Shen-xin 《Transition Metal Chemistry》2004,29(4):388-393
The Schiff base complexes containing a transition metal ion, CoII and CuII, were used as mimetic peroxidase in the catalytic oxidation of phenol by H2O2. The characteristic spectra of the Schiff base complexes in H2O2-buffered solution were recorded and analyzed, respectively. The mechanism and the kinetic mathematic model of the phenol catalytic oxidation were studied. The results showed that the Schiff base complexes containing the transition metal ion, CoII and CuII, as peroxidase mimics exhibited good catalytic activity and the character of the peroxidase in the catalytic oxidation of phenol by H2O2 under different conditions. 相似文献
6.
Jia-qing Xie Fa-mei Feng Shen-xin Li Fuan Liu 《Journal of Dispersion Science and Technology》2013,34(9):1311-1318
The intramolecular nucleophilic substitution of an activated phosphate diester, bis(p-nitrophenyl) phosphate (BNPP) as the nucleic acids substitute, was investigated. A macro-cyclic ligand and the corresponding Cu (II) and Ni (II) complexes were synthesized and characterized. The metallomicelles made up of macrocyclic divalent metal complex and micelle, as mimic hydrolytic metalloenzyme, was used in BNPP catalytic hydrolysis. The metallomicelles displayed higher catalytic activity although they do not attain the catalytic efficiency of enzymes. The analysis of specific absorption spectra showed that the course of the BNPP catalytic reaction was different from that of the BNPP spontaneous hydrolysis, and was an intramolecular nucleophilic substitution reaction. Based on the analytic result of the specific absorption spectrum, an intramolecular nucleophilic substitution mechanism of BNPP catalytic hydrolysis was proposed and a correlative kinetic mathematical model was established, and the corresponding thermodynamic and kinetic constant was calculated. The result of this study proved validity of the mechanism and mathematical model proposed in the article. 相似文献
7.
CaSO4∶Eu是一种人们早已较为熟知的发光材料,由于其优异的热释发光特性而被广泛应用于辐射剂量学方面。近年来由于崭新的光致发光液晶显示模式的出现,人们又对其近紫外发射特性产生了极大兴趣。考察了CaSO4∶Eu的发光特性和材料的各种制备方法,以及制备条件对发光性能的影响,特别是对其近紫外发射性能的影响。实验表明,对于还原彻底、结晶良好的样品,激活剂Eu几乎全部以二价铕离子的形式存在,是一种很好的近紫外发射材料。该材料能被低压汞蒸气放电辐射有效激发,其发射带的峰值在386 nm附近,随Eu的掺杂浓度不同而略有差异,半峰全宽约为16 nm,基本满足了近紫外发射的要求,可应用于光致发光液晶显示器件的背照明光源中。 相似文献
8.
9.
Jian-zhang Li Bin Xu Ying Wang Shen-xin Li Bo Zhou Wei Zeng Sheng-ying Qin 《Transition Metal Chemistry》2006,31(4):487-494
Two novel unsymmetrical bis-Schiff base manganese(III) and cobalt(II) complexes with benzo-10-aza-crown ether pendants (MnL1Cl, CoL1), and their analogoues with morpholino pendants (MnL2Cl, CoL2), have been synthesized and employed as models to mimic hydrolase in p-nitrophenyl picolinate (PNPP). The kinetics and the mechanism of PNPP hydrolysis catalyzed by these complexes were investigated.
A kinetic mathematical model of PNPP cleavage catalyzed by these complexes was proposed. The effects of the complexes structure
and reactive temperature on the rate of catalytic PNPP hydrolysis have been also examined. The results showed that the rate
for the catalytic PNPP hydrolysis increased following the increase in pH of the buffer solution; four complexes exhibited
high activity in the catalytic PNPP hydrolysis. Compared with the crown-free analogoues MnL2Cl and CoL2, the crowned Schiff base complexes (MnL1Cl, CoL1) exhibit a higher catalytic activity; the pseudo-first-order-rate (kobs) for the PNPP hydrolysis catalyzed by the complex MnL1Cl containing benzo-10-aza-crown ether is 1.04 × 103 that of spontaneous hydrolysis of PNPP at pH = 7.00, [S] = 2.0×10−4 mol dm−3. 相似文献
10.
CaSO4:Eu是一种人们早已较为熟知的发光材料,由于其优异的热释发光特性而被广泛应用于辐射剂量学方面。近年来由于崭新的光致发光液晶显示模式的出现,人们又对其近紫外发射特性产生了极大兴趣。考察了CaSO4:Eu的发光特性和材料的各种制备方法,以及制备条件对发光性能的影响,特别是对其近紫外发射性能的影响。实验表明,对于还原彻底、结晶良好的样品,激活剂Eu几乎全部以二价铕离子的形式存在,是一种很好的近紫外发射材料。该材料能被低压汞蒸气放电辐射有效激发,其发射带的峰值在386nm附近,随Eu的掺杂浓度不同而略有差异,半峰全宽约为16nm,基本满足了近紫外发射的要求,可应用于光致发光液晶显示器件的背照明光源中。 相似文献