排序方式: 共有10条查询结果,搜索用时 15 毫秒
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研究了用传统方法在1200~1400℃烧结的ZnO陶瓷,以及用放电等离子体烧结(SPS)方法烧结的ZnO陶瓷的结构特征与电学性能。以ZnO为基添加了不同浓度的LiOH,制备了不同Li掺杂浓度的ZnO陶瓷。研究了掺杂、烧结温度,以及烧结方法等因素对ZnO基陶瓷的微观结构、电学性能的影响。实验表明,用传统方法烧结时,ZnO在烧结温度低于1400℃的情况下难以成瓷,而放电等离子体烧结(SPS)方法可以显著降低烧结温度。ZnO陶瓷的晶粒大小。密度随着烧结温度的增大而增大。在同样的烧结温度下,LiOH含量越大,ZnO基陶瓷的电阻率越大。 相似文献
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为了实现高平坦的自发辐射输出,提出并设计了一种基于974nm泵浦源和高掺杂浓度掺铒光纤的平坦宽带光源。系统以泵浦波长974nm的激光二极管作为泵浦源,先将泵浦光分为两路对掺铒光纤分级泵浦,再将铒离子产生的自发辐射光合并输出,并调节铒纤长度和泵浦功率对输出光谱进行优化。仿真结果表明:泵浦功率为160mW,两段掺铒光纤长度分别为7m和2m时,可以在1530~1610nm得到带宽为80nm,功率为20.348mW,平坦度为±1.268dB的光谱输出。该系统在不额外增加滤波器且光纤总长小于10m的前提下,实现平坦宽带输出,有望在光纤传感系统中得到应用。 相似文献
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聚氨酯具有许多优异性能,如耐磨损、耐油、耐撕裂、耐化学腐蚀、与其他材质黏结性好、高弹性和吸震能力强等。该课题完成了聚氨酯支撑材料的堆照实验,在残余放射性达到自然本底后取出聚氨酯材料,对聚氨酯材料进行气相色谱(GC)、动态力学性能(DMA)、压缩性能和正电子湮没(PAL)等分析研究,探讨了聚氨酯材料的性能和结构变化规律。 相似文献
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利用高温固相法合成了稀土离子Eu2+, Dy3+掺杂的Ca5MgSi3O12长余辉发光材料. 利用光谱学证明了在材料内部存在与氧空位有关的缺陷发光. 通过对比不同条件下合成样品的发光及余辉性能, 发现氧空位对材料的发光及余辉均起到促进作用. 同时发现氧空位发光可以向发光中心传递能量. 利用热释光曲线系统的分析了氧空位对余辉性能的影响. Ca5MgSi3O12:Eu2+,Dy3+是一种潜在的长余辉发光材料.
关键词:
长余辉
氧空位
能量传递
热释光 相似文献
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为了满足在隧道环境中实现高速率、高质量无线通信的迫切需求,研究了适用于隧道环境的高增益天线,提出了利用二元相控阵天线系统提高隧道内信号传输质量的新方法。相控阵天线系统由两个高增益天线单元及一个移相器组成,通过移相器调整其中一个天线单元的相位,使隧道内合成电场的最小值幅值达到最大,提升信号的平均场强。仿真结果表明:与单个天线发射信号相比,在3 000 m隧道轴向传播范围内,相控阵天线系统发射信号合成电场的最低电平最少提升了19.6 dB;与两个天线同时发射信号相比,最低电平最少提升了12.4 dB,取得较好分集优化效果,消除多径效应导致的深度衰落,解决了隧道环境中存在的通信问题。
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Uranyl (Ⅵ) amidoxime complexes are investigated using relativistic density functional theory. The equilibrium structures, bond orders, and Mulliken populations of the complexes have been systematically investigated under a generalized gradient approximation (GGA). Comparison of (acet) uranyl amidoxime complexes ([UO 2 (AO) n ] 2 n , 1≤ n ≤4) with available experimental data shows an excellent agreement. In addition, the U-O(1), U-O(3), C(1)-N(2), and C(3)-N(4) bond lengths of [UO 2 (CH 3 AO) 4 ] 2 are longer than experimental data by about 0.088, 0.05, 0.1, and 0.056 A. The angles of N(3)-O(3)-U, O(2)-N(1)-C(1), N(3)-C(3)-N(4), N(4)-C(3)-C(4), and C(4)-C(3)-N(3) are different from each other, which is due to existing interaction between oxygen in uranyl and hydrogen in amino group. This interaction is found to be intra-molecular hydrogen bond. Studies on the bond orders, Mulliken charges, and Mulliken populations demonstrate that uranyl oxo group functions as hydrogen-bond acceptors and H atoms in ligands act as hydrogen-bond donors forming hydrogen bonds within the complex. 相似文献
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Uranyl (VI) amidoxime complexes are investigated using relativistic density functional theory. The equilibrium structures, bond orders, and Mulliken populations of the complexes have been systematically investigated under a generalized gradient approximation (GGA). Comparison of (acet) uranyl amidoxime complexes ([UO2(AO)n]2-n, 1 ≤ n ≤ 4) with available experimental data shows an excellent agreement. In addition, the U-O(1), U-O(3), C(1)-N(2), and C(3)-N(4) bond lengths of [UO2(CH3AO)4]2- are longer than experimental data by about 0.088, 0.05, 0.1, and 0.056 Å. The angles of N(3)-O(3)-U, O(2)-N(1)-C(1), N(3)-C(3)-N(4), N(4)-C(3)-C(4), and C(4)-C(3)-N(3) are different from each other, which are due to existing interaction between oxygen in uranyl and hydrogen in amino group. This interaction is found to be intra-molecular hydrogen bond. Studies on the bond orders, Mulliken charges, and Mulliken populations demonstrate that uranyl oxo group functions as hydrogen-bond acceptors and H atoms in ligands act as hydrogen-bond donors forming hydrogen bands within the complex. 相似文献
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