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741.
Introduction In a series of papers the authors reported the spec-troscopy results on upconversion luminescence of the double salts between the alkali metal (Rb,Cs) halide and rare earth metal trihalide (REX3).1-4 Consequently, ex-tensive syntheses of new double salts and studies on optical properties of such species have received much more attention.5-12 Although a number of these double salts have been synthesized, the formation in alkali metal halide/rare earth metal halide double salts s… 相似文献
742.
Gao-mai Yang Jun Li Yan-wei Ren Hui Guo Min-yue Duan Feng-xing Zhang Xiongfu Zhang 《Transition Metal Chemistry》2009,34(2):191-196
Four new dinuclear complexes of the type [M2(cyclen)2(suc)]Cl2 · nH2O (M = Co2+, Ni2+, Cu2+, Zn2+, cyclen = 1,4,7,10-tetraazacyclododecane, suc = succinate) have been obtained by the reaction of cyclen and succinate with
the corresponding metal dichlorides in aqueous solution. All the complexes were characterized by physico-chemical and spectroscopic
methods. The crystal structure of [Ni2(cyclen)2(suc)]Cl2 · 2H2O was determined. The four complexes have similar compositions and structures and are all bridged by succinate. Furthermore,
the hydrolysis of bis(2,4-dinitrophenyl)phosphate (BDNPP) promoted by the four complexes was studied. The experimental results
indicate that these complexes can efficiently catalyze hydrolysis of BDNPP, and their catalytic activities are in the order
Ni > Zn > Cu > Co. 相似文献
743.
Zheng Yang Mengyao She Bing Yin Likai Hao Martin Obst Ping Liu Jianli Li 《Analytica chimica acta》2015
A novel, solvent-dependent “off–on” probe with benzoylthiourea moiety as the functional receptor and fluorescein as the fluorophore was designed for monitoring of Ag+ in EtOH–H2O (2:8, v/v) solution and Zn2+ in CH3CN–H2O (2:8, v/v) solution at physiological range with sufficient selectivity and sensitivity. The Ag+ promoted desulfurization of thiosemicarbazide functionality in formation of the 1,3,4-oxadiazole and the coordination of Zn2+ to the O atom and N atom of the spoirolactam moiety and the S atom of the benzoylthiourea moiety were investigated to be the power that promoted the fluorescent enhancement. This probe was tested highly suitable for mapping Ag+ and Zn2+ in living human osteosarcoma MG-63 cells and microbial cell–EPS–mineral aggregates, thus, providing a wonderful candidate for tracking Ag+ and Zn2+ in biological organisms and processes. 相似文献
744.
Xianzhong Zhao 《Semigroup Forum》2002,64(2):289-296
For every semigroup S , we define a congruence relation ρ on the power semiring (P(S),\cup,\circ) of S . If S is a band, then P(S)/ρ is an idempotent semiring . This enables us to find models for the free objects in the variety of idempotent semiring s
whose additive reduct is a semilattice.
December 28, 1999 相似文献
745.
多模叠加态|Ψe4,Ⅲ〉q中广义电场分量的N次方H压缩 总被引:3,自引:0,他引:3
利用多模压缩态理论,详细研究了由多模偶相干态和多模虚偶相干态的线性叠加所组成的一种新型的四态叠加多模叠加态光场|Ψe4,Ⅲ〉q中广义电场分量的等幂次N次方H压缩特性结果表明:1)在腔模总数q与压缩次数N的乘积q·N=4m(m=1,2,3,…)的条件下,态|Ψe4,Ⅲ〉q的广义电场分量可恒处于等幂次NH最小测不准态2)在q·N=4m’+2(m’=0,1,2,…)的条件下,当态间的初始相位差(θ1-θ2)、各模的初始相位和 φj,以及各模平均光子数之总和 Rj2等分别满足一定的取值条件时,态|Ψe4,Ⅲ〉q的广义电场分量总可呈现出周期性变化的偶数次的等幂次N次方H压缩效应. 相似文献
746.
Six new lanthanide(III) complexes (i.e., [Ln(L)2(NA)1.5]·3H2O, where Ln=La(III), Pr(III), Nd(III), Sm(III), Gd(III), and Ce(III) and L and NA indicate N2H4 and C10H6(1-O)(2-COO), respectively) with 1-hydroxy-2-naphthoic acid [C10H6(1-O)(2-COOH)] and hydrazine (N2H4) as co-ligands were characterized by elemental, FTIR, UV-visible, and XRD techniques. In the FT-IR spectra, the N-N stretching frequency in the range of 981–949 cm−1 demonstrates evidence of the presence of coordinated N2H4, indicating the bidentate bridging nature of hydrazine in the complexes. These complexes show symmetric and asymmetric COO− stretching from 1444 to 1441 cm−1 and 1582 to 1557 cm−1, respectively, indicating bidentate coordination. TG-DTA studies revealed that the compounds underwent endothermic dehydration from 98 to 110 °C. This was followed by the exothermic decomposition of oxalate intermediates to yield the respective metal oxides as the end products. From SEM images, the average size of the metal oxide particles prepared by thermal decomposition of the complexes was determined to be 39–42 nm. The powder X-ray and SEM coupled with energy dispersive X-ray (EDX) studies revealed the presence of the respective nano-sized metal oxides. The kinetic parameters of the decomposition of the complexes were calculated using the Coats-Redfern equation. 相似文献
747.
Two new nitrone alkaloids were isolated from the whole plant of Huperzia serrata (Thunb .) Trev . They are both phlegmarine‐type lycopodium alkaloids with a nitrone moiety. Their structures were elucidated on the basis of spectral evidences, and their configurations were established on the basis of optical rotation, CD, and NOESY‐NMR data. 相似文献
748.
Effect of Mn-doping on the growth mechanism and electromagnetic properties of chrysanthemum-like ZnO nanowire clusters 下载免费PDF全文
Chrysanthemum-like ZnO nanowire clusters with different Mn-doping concentrations are prepared by a hydrothermal process. The microstructure, morphology and electromagnetic properties are characterized by x-ray diffractometer high-resolution transmission electron microscopy (HRTEM), a field emission environment scanning electron microscope (FEESEM) and a microwave vector network analyser respectively. The experimental results indicate that the as-prepared products are Mn-doped ZnO single crystalline with a hexagonal wurtzite structure, that the growth habit changes due to Mn-doping and that a good magnetic loss property is found in the Mn-doped ZnO products, and the average magnetic loss tangent tanδm is up to 0.170099 for 3% Mn-doping, while the dielectric loss tangent tanδe is weakened, owing to the fact that ions Mn2 + enter the crystal lattice of ZnO. 相似文献
749.
Let B(X) be the algebra of all bounded linear operators on a complex Banach space X. We give the concrete form of every unital surjective map φ on B(X) such that AB is a non-zero idempotent if and only if φ(A)φ(B) is for all A,B∈B(X) when the dimension of X is at least 3. 相似文献
750.
Asymmetric W-shaped and M-shaped soliton pulse generated from a weak modulation in an exponential dispersion decreasing fiber 下载免费PDF全文
We study localized waves on continuous wave background in an exponential dispersion decreasing fiber with two orthogonal polarization states. We demonstrate that asymmetric W-shaped and M-shaped soliton pulse can be generated from a weak modulation on continuous wave background. The numerical simulation results indicate that the generated asymmetric soliton pulses are robust against small noise or perturbation. In particular, the asymmetric degree of the asymmetric soliton pulse can be effectively controlled by changing the relative frequency of the two components. This character can be used to generate other nonlinear localized waves, such as dark–antidark and antidark–dark soliton pulse pair, symmetric W-shaped and M-shaped soliton pulse. Furthermore, we find that the asymmetric soliton pulse possesses an asymmetric discontinuous spectrum. 相似文献