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51.
KAlF4:Ce,Tb磷光体的发光特性及Ce^3+对Tb^3+的敏化作用 总被引:6,自引:3,他引:3
采用溶液反应法和高温固相反应法合成了KA1F4基质化合物及KA1F:Ce,Tb磷光体,测定了磷光体的激发光谱和发射光谱,研究了在碱金属氟铝酸盐基质中Ce^3+对Tb^3+的能量传递,根据Ce^3+,Tb^3+在KAlF4中的能级关系,分析了其发光特性和Ce^3+对Tb^3+能量传递过程。 相似文献
52.
Chen Youcun Liu Guangxiang Xu Heng Zhou Hong Ren Xiaoming 《Russian Journal of Coordination Chemistry》2003,29(4):251-255
Two complexes [PyH][Ni(Mnt)2] (I) and [QlH][Ni(Mnt)2] (II) (Mnt2– = maleonitriledithiolate, [PyH]+ = pyridinium, [QlH]+ = quinolinium) were synthesized and characterized by elemental analysis and IR spectra. ESR spectra of polycrystalline samples collected at room temperature are isotropic with g = 2.039 for Iand anisotropic with g
z = 1.997, g
y g
x = 2.102 (g
av = 2.068) for II. The magnetic susceptibility data of I and II have been measured in the temperature range of 2–300 K. The results obtained suggest the antiferromagnetic coupling interactions between neighboring Ni3+ ions for I and ferromagnetic coupling interactions for II, respectively. Based on the crystal structure analysis of I, the magnetic properties of two complexes were discussed. 相似文献
53.
Wanghua Xu 《大学化学》2020,35(2):135-139
Through the analysis of several valuable chemical contest problems, the students' spatial visualization and divergent thinking abilities were improved, and the teaching's advice was provided. 相似文献
54.
在状态空间是可数情形下,本文给出了时间随机环境下随机游动的一个一般模型.随后,在环境是独立同分布情形下得到了直线上时间随机环境下紧邻随机游动的一个常返与暂留准则和强大数定律;最后讨论了其中心极限定理,它类似与简单随机游动的相应结果. 相似文献
55.
56.
PbS nanotubes were synthesized by the tiny water channels in bicontinuous microemulsions consisted of p-octyl polyethylene glycol phenylether (OP)/n-amyl alcohol/cyclohexane/water. The possible formation mechanism of PbS nanotubes is also discussed based on their shape evolutions. The results indicate that the formation of PbS nanotubes is probably via the process of the nucleation, growth, assemblage and crystallization. 相似文献
57.
A novel compound [(IBz)2Im](TCNQ) [(IBz)2Im=1,3-bis(4-iodobenzyl) imidazole cation, TCNQ-=7,7,8,8-tetracyanoquinodimethanide anion] was synthesized by the reaction of [(IBz)2Im]Br and LiTCNQ in CH3OH and its structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c with a=1.147 35(18) nm, b=2.028 1(3) nm, c=1.264 1(2) nm, β=104.73(0)°, V=2.666(65) nm3, Z=4, C29H19I2N6, Mr= 705.30, Dc=1.757 g·cm-3, R1=0.053 2 and wR2=0.111 2. The structure analysis shows that the anions are stacked into column with isolated π-dimers, and there is one type of TCNQ entries (TCNQ-), in agreement with the IR spectra analysis of the compound. The most prominent structural features are the completely segregated stacking columns of the TCNQ-anions and [(IBz)2Im]+ cations. CCDC: 759523. 相似文献
58.
59.
《Comptes Rendus de l''Academie des Sciences Series IIB Mechanics Physics Astronomy》1998,1(2):115-121
The structure of the new compound Eu27T20X2S54O12 (X ≈ I0.35 Cl0.65), prepared by solid state reaction, contains ∞2[(Ti4S2O4)(Ti2S10)4/2] planes built up from rutile-like chains that cross perpendicularly. Two [TiS6] octahedra separate the [Ti4S2O4] clusters at the chain intersections. These planes are separated by a corrugated layer of [Ti3S8O4] triplets of face-sharing Ti-centered octahedra. Five crystallographically independent europium ions are seven- to nine-coordinated. 相似文献
60.
一维链状配合物[BrBzPy][Ni(dmit)2]的合成和红外光谱研究 总被引:1,自引:0,他引:1
合成了一种新的化合物[BrBzPy][Ni(dmit)2](1),并进行了红外光谱表征.晶体的结构结果表明它的空间点群为P21/c,a=0.627 5(1)nm,b=1.743 8(3)nm,c=2.283 9(3)nm,α=90°,β=9.187(1)nm,γ=90°,V=2.497(7)nm3,Z=4,Mr=700.57,Dc=1.863 g·cm-3.晶体中[Ni(dmit)2]-非常接近平面,共轭性相当显著,且成为一维链状结构. 相似文献