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The graft copolymerization of MMA onto human dentin was studied with the redox system usingK_2S_2O_8+NaHSO_3 as initiator. The IR spectrum of the copolymer showed the presence of C=Oband at 1720 cm~(-1),C--O at 1260~(-1), CH_3, at 2850 cm~(-1). indicating the presence of polymerized me-thacrylate on the detin. The ppt. of the acid hydrolysis of the graft copolymer showed an -NH_3~+band of amino acid at 3200 cm~(-1). Most marked percent decreases in contents of amino acids inthe acid hydrolysate were observed in serine, tyrosine and methionine. The absolute amounts ofglycine, alanine and proline have also decreased markedly. This suggests that it was most proba-ble that the graft copolymerization occurred at these residues. The tubular stripes and cross sectioncavities of dentin tublets were covered with a high polymer graft which could be seen from the SEMpictures. The mol. wt. of this grafted high polymer, as determined by GPC, was higher than thatof the homopolymer and the former had a broader mol. wt. distribution. All these facts suggest-ed that a genuine graft copolymerization of MMA onto human dentin occurred. 相似文献
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研究了ZnS:ErF_3和ZnS:HoF_3两种材料制备的交流驱动的绿色电致发光薄膜(ACELTF)的发光亮度和色度与ErF_3和HOF_3掺杂浓度的关系。对于ZnS:ErF_3和ZnS:HoF_3,其最佳掺杂浓度分别为7×10~(-3)和2×10~(-3)mol/mol基质;获得的最高发光亮度分别为900cd/m~2和550cd/m~2。当ErF_3的掺杂浓度由3×10~(-4)mol/mol基质增至3×10~(-1)mol/mol基质时,ZnS:ErF_3薄膜的色座标(x,y值)由0.251,0.664变为0.392,0.586;当HOF_3的掺杂浓度由3×10~(-4)mol/mol基质增至1×10~(-1)mol/mol基质时,ZnS:HoF_3薄膜的色座标值由0.315,0.615变为0.472,0.521。 相似文献
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制取氯气,并且在其中燃烧金属钠,红磷,锑及铁粉的实验,可以不需要通风橱而在如下的一套仪器中进行: 相似文献
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本文研究了Er~(3+)离子浓度对ZnS:ErF_3薄膜交流电致发光(ACEL)特性的影响。I(~4F_(9/2)→~4I_(15/2))受Er~(3+)离子浓度的影响较大,随Er~(3+)离子浓度增高,I(~4F_(9/2)→~4I_(15/2))增强,甚至超过I(~2H_(11/2)→~4I_(15/2))。通过研究具有不同Er~(3+)离子浓度样品的电致发光衰减,绿红比随外加电压的变化关系以及不同能级的电致发光效率,我们发现,粒子从~4S_(3/2)和~2H_(11/2)能级向~4F_(9/2)能级弛豫是使I(~4F_(9/2)→~4I_(15/2))增强的主要原因。随Er~(3+)离子浓度增高,交叉弛豫速率也增高,因而使I(~4F_(9/2)→~4I_(15/2))随浓度的增高而增强。 相似文献
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ZnS:ErF3电致发光薄膜2H11/2,4S3/2→4I15/2发光的猝灭过程 总被引:1,自引:0,他引:1
本文通过ZnS:ErF3交流电致发光薄膜发光光谱和发光衰减特性研究了Er3+离子2H11/2,3S3/2发光的猝灭过程,实验结果表明由于Er3+离子间多极矩相互作用,一个激发的Er3+离子从2H11/2态无辐射弛豫到4F9/2态,同时另一个激发的Er3+离子从4F7/2或4F5/2+4F3/2态跃迁到2H9/2或4G11/2态的交叉弛豫过程是2H11/2,4S3/2发光浓度猝灭的一个主要机制,交叉弛豫几率随着掺杂浓度的增加而增大,根据在固定掺杂浓度下2H11/2,4S3/2、4F9/2发光衰减时间不随激发密度而改变的实验结果,排除了处于激发的Er3+离子之间直接能量传递的可能性,这结果与扩散限制的能量传递理论相符。 相似文献