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采用液相沉淀法合成了铽单掺杂,铕单掺杂,铽、铕双掺杂的硅酸锶发光材料。其结构经X-射线衍射表征。研究了合成样品的激发、发光光谱。研究结果表明:在254nm波长紫外光激发下,SrSiO3:0.04Eu3+的发光光谱中出现4个Eu3+的发光峰,分别为Eu3+的5D0→7F1(588、590nm)、5D0→F2(609nm)、5D0→7F3(626nm)、5D0→4F4(651nm)跃迁峰;SrSiO3:0.04Tb3+的发光光谱中出现4个Tb3+的发光峰,分别为Tb3+的5D4→F6(488nm)、5D4→7F5(541、548nm)、5D4→7F4(584nm)跃迁峰;SrSiO3:0.04Tb3+,0.04Eu3+发光体系中,Tb3+的共掺杂显著增强了Eu3+的特征发射,存在Tb3+→Eu3+的能量传递现象,结果表明有Eu3+和Tb3+两个发光中心。 相似文献
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囊泡表面分子间通讯交流体系的构建: 利用受体的分子识别行为调控酶的活性 总被引:1,自引:0,他引:1
在人工双层膜囊泡表面, 构建了一个通过人工受体的分子识别行为控制酶反应活性的超分子体系. 体系以生物体细胞信号转导系统为模拟原型, 由作为受体的烷基胺、被受体识别的信号分子吡哆醛衍生物、乳酸脱氢酶、受体和酶之间的媒介物Cu2+以及作为体系载体的合成肽脂囊泡五个成分构成.通过UV-vis光谱法及动态光散射测定对体系进行了评价, 结果表明: 随着受体疏水参数增大, 其对信号分子的识别能力增强, 二者呈良好的线性关系; 通过信号分子与囊泡表面静电相互作用的研究表明信号分子具有选择性; 媒介物与信号分子–受体可形成化学计量比为1∶2的配合物, 其形成能力比媒介物与酶的结合能力更强.作为结论, 体系中烷基胺受体对磷酸吡哆醛信号分子的识别有效控制了处于囊泡表面的乳酸脱氢酶的活性. 相似文献
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In this paper, the palaeomagnetic study of the 55 oriented samples collected from some Late Cenozoic basalt group of Datong region has been carried out. The results show that the magnetic declinations of all specimens indicate eastward deviation, a shallower inclination than the present value and large amplitude of the secular variation. Site B records a short reversed episode during the late Brunhes Epoch, and it may be correlated with the Blake Event. 相似文献
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Based on the hexagonal BN structure, six possible layered B~ CN structures are constructed. Their total energies, lattice constants as well as electronic properties are calculated using the ab initio pseudopotential density functional method within the local density approximation. The calculated results show that the B2 CN-V configuration with AA stacking sequence is the most stable among the six B2CN layered structures. The characteristics of electronic structures indicate that the B2 CN-V shows metallicity, which mainly comes from -B1-C-B1-C- chains. 相似文献
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A sequential decay model is used to study isoscaling, i.e. the factorization of the isotope ratios from sources of different isospins and sizes over a broad range of excitation energies, into fugacity terms of proton and neutron number, R21(N, Z) = Y2( N, Z)/Y1( N, Z) = Cexp(αN -βZ). It is found that the isoscaling parameters α and β have a strong dependence on the isospin difference of equilibrated source and excitation energy, no significant influence of the source size on α andβ has been observed. It is found that α and β decrease with the excitation energy and are linear functions of 1/T and △(Z/A)2 or△(N/A)2 of the sources. Symmetry energy coefticient Gsym is constrained from the relationship of a and source △(Z/A)2, /3 and source △(N/A)2. 相似文献
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用超分子MP4方法和大基组(aug-cc-pVTZ)及键函数得到He-N2O体系的分子间从头算势能面及偶极矩面.用离散变量表象方法计算了^4He-N2O及^3He-N2O体系的振转能级,并进一步计算得到其振转跃迁强度,计算结果很好地解释了实验现象。 相似文献
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