聚氨酯结构与径向分布的分子动力学模拟

采用分子动力学方法计算得到DHI-乙烯醇聚合体系统的结构和径向分布函数.讨论了系统结构和径向分布函数与温度和压力之间的关系.结果表明粘合系统的空间分布一般地随着温度和压力的增加而收窄,对增加聚氨酯系统的粘合性具有积极的意义.     

激光调频连续波测距的精度评定方法研究

基于双光纤光路等光频重采样原理,提出了一种距离精度的评定方法.通过推导噪声背景下等光频重采样信号中距离参量的克拉美-罗下边界,得到了影响系统测距精度的两个重要因素:信噪比和扫描带宽,并进行了实验验证.实验表明,该评价方法并不会受到任何距离估算方法的影响,根据此方法可以选择一个最优的距离估算方法.通过对两个影响精度的因素进行仿真分析可知,在扫描带宽为2.2 nm时,若将测量光路的信噪比提升至70 dB以上,系统可获得低于10μm的测距精度.该精度评定方法可为后续改善调频连续波测距系统性能提供理论参考.     

碳纳米管锁模双包层光纤激光器的实验研究

本文采用双包层掺镱光纤作为增益介质,用单壁碳纳米管作为饱和吸收体,获得最高输出功率为336 mW的锁模脉冲激光.用飞秒激光诱导水击穿法直接在单模光纤上制备出D形区,通过在D形光纤上滴涂单壁碳纳米管溶液,成功制备出碳纳米管饱和吸收体,并对其饱和吸收特性进行测试,发现其调制深度为27％.利用该饱和吸收体作为锁模器件,制备出具有环形腔结构的锁模光纤激光器.当抽运功率为4W时,获得了脉宽为93.8 fs,中心波长为1083.8 nm,3 dB谱宽为8.6 nm,重复频率为5.59 MHz,平均功率为336 mW的飞秒脉冲激光输出.     

Simulation of a 2-site Langmuir model for characterizing the sorption capacity of Cs and Se in crushed mudrock under various ionic strength effects

The sorption capacity of cesium (Cs) and selenium (Se) in crushed mudrock was demonstrated in this study through a 2-site Langmuir model. To employ such a numerical analysis, batch tests were applied in this study in synthetic seawater and groundwater with sorption/desorption kinetic experiments (time-dependent) and different concentrations (10^?2–10^?7 M). The 2-site sorption models, which correspond to two rate constants (λ ₁ and λ ₂), might be more adequate than 1-site sorption models in characterizing Cs and Se sorption/desorption according to the least square errors between the numerical analysis and the results of the batch tests. The fitting results showed that a 2-site Langmuir model is capable of appropriately describing Cs and Se sorption in mudrock. Consequently, the sorption capacity was calculated at about 0.06 mol/kg for Cs and at 0.015 mol/kg for Se.     

HTS双饼线圈的加工工艺及实验研究

详细介绍了高温超导双饼线圈的加工工艺和流程,针对绕制时带材弯曲形变使临界电流退化的技术难点,重点阐述了其解决方法。在液氮温度、自场环境下对采用该加工工艺制作的YBCO双饼线圈及Bi2223/Ag双饼线圈进行低温实验,测试其V-I特性曲线。实验结果表明:该工艺制作的双饼线圈性能良好,工艺安全可靠,是合适的。同时,实验测量数据也为线圈在磁体中的进一步应用提供了可靠依据。     

Facile filling of metal particles in small carbon nanotubes for catalysis

A versatile wet chemistry method is developed for filling of subnanometer sized metal particles in carbon nanotubes with a diameter smaller than 1.5 nm. As an example, we showed that a confined bi-component Pd-V catalyst exhibit a higher benzene hydroxylation activity compared with that within multi-walled carbon nanotubes.     

An optical study of the D-D neutron irradiation-induced defects in Co-and Cu-doped ZnO wafers

Room-temperature photoluminescence and optical transmittance spectroscopy of Co-doped(1×1014,5×1016,and 1×1017cm-2) and Cu-doped(5×1016cm-2) ZnO wafers irradiated by D-D neutrons(fluence of 2.9×1010 cm-2) have been investigated.After irradiation,the Co or Cu metal and oxide clusters in doped ZnO wafers are dissolved,and the wu¨rtzite structure of ZnO substrate for each sample remains unchanged and keeps in high c-axis preferential orientation.The degree of irradiation-induced crystal disorder reflected from the absorption band tail parameter(E0) is far greater for doped ZnO than the undoped one.Under the same doping concentration,the Cu-doped ZnO wafer has much higher irradiation-induced disorder than the Co-doped one.Photoluminescence measurements indicate that the introduction rate of both the zinc vacancy and the zinc interstitial is much higher for the doped ZnO wafer with a high doping level than the undoped one.In addition,both crystal lattice distortion and defect complexes are suggested to be formed in doped ZnO wafers.Consequently,the Co-or Cu-doped ZnO wafer(especially with a high doping level) exhibits very low radiation hardness compared with the undoped one,and the Cu-doped ZnO wafer is much less radiation-hard than the Co-doped one.     

光致变色多阶游程光存储研究

多阶游程存储是一种不改变光学系统而显著提高光存储容量和数据传输率的新方法.介绍了光致变色多阶游程存储原理和实验系统.提出了基于光致变色原理的多阶游程存储数学模型，该模型反映了记录符反射率与曝光功率、曝光时间之间的非线性关系，并在此基础上确定了光致变色多阶游程存储的写策略.基于650nm光致变色材料进行了4阶游程存储的动态实验.结果表明，实验中采用的650nm光致变色材料可用于多阶游程存储，采用的写策略能够有效地使记录信道线性化，利于采用适合线性系统的信号处理方法. 关键词： 多阶游程 光致变色 光存储 写策略     

具有超小光斑点和高通光效率的AlGaAs 四面锥尖的模拟和优化

本文我们利用时域有限差分方法研究和比较了四种类型探针的光发射斑点和通光效率，在这些探针中，全镀薄金属银膜的AlGaAs 四面锥尖可提供最高的通光效率和单个近场光斑点。探针镀有3 nm银膜并利用波长800 nm入射光照射是提供高通光效率和超小光斑点的优化条件，高通光效率和超小光斑点的光探针使我们能实现超高密度光存储。