苄基四甲基环戊二烯基钼羰基化合物的合成及晶体结构

C₅Me₄(benzyl)H reacted with Mo(CO)₆ in refluxing xylene to give the new complex (C₅Me₄benzyl)₂Mo₂(CO)₆. Its molecular structure was characterized by elemental analysis, IR spectra, ¹H NMR and X-ray diffraction. Crystal data for this compound: Triclinic, space group P1, M_r=782.56, a=0.854 43(17) nm, b=0.991 0(2) nm, c=1.035 5(2) nm, α=67.25(3)°, β=87.38(3)°, γ=85.99(3)°, V=0.806 4(3) nm³, Z=1, D_c=1.611 g·cm³, μ(Mo Kα)=0.825 mm^-1, F(000)=398, R=0.032 9, wR=0.083 6 (observed reflections with I>2σ(I)) and R=0.036 2, wR=0.084 3 (all reflections). The X-ray crystal structure of the dimer confirms the structure with terminal CO groups and the Mo-Mo bond distance is 0.326 6 nm. CCDC: 693386.     

基于连续弯液面构筑的有序阵列模板复制模塑制备图案化聚合物薄膜

基于咖啡环理论, 利用微米尺度限制下的弯液面溶剂散逸过程获得表面微结构可控的有序阵列, 以此为母模板制备聚二甲基硅氧烷(PDMS)弹性印章, 通过复制模塑过程实现阵列结构转移. 利用广义Young-Laplace方程建立的理论模型分析弯液面聚合物沉积黏连过程, 推导出条纹沉积频率与聚合物分子量、 基底滑动速率和溶液浓度的关系, 理论计算结果与实验现象一致.     

Synthesis of large diamond crystals containing high-nitrogen concentration at high pressure and high temperature using Ni-based solvent by temperature gradient method

This paper reprots that with Ni-based catalyst/solvent and with a dopant of NaN 3,large green single crystal diamonds with perfect shape are successfully synthesized by temperature gradient method under high pressure and high temperature in a China-type cubic anvil high-pressure apparatus (SPD-6×1200),and the highest nitrogen concentration reaches approximately 1214-1257 ppm calculated by infrared absorption spectra.The synthesis conditions are about 5.5 GPa and 1240-1300 C.The growth behaviour of diamond with high-nitrogen concentration is investigated in detail.The results show that,with increasing the content of NaN 3 added in synthesis system,the width of synthesis temperature region for growth high-quality diamonds becomes narrower,and the morphology of diamond crystal is changed from cube-octahedral to octahedral at same temperature and pressure,the crystal growth rate is slowed down,nevertheless,the nitrogen concentration doped in synthetic diamond increases.     

基于纯相位调制的散射介质传输矩阵测量与光波聚焦

提出了基于纯相位调制的传输矩阵通用测量方法,搭建了传输矩阵测量的实验装置。分别利用单位矩阵调制和哈达玛矩阵调制方式进行了传输矩阵测量,并实现了穿透散射介质的光波聚焦。实验结果表明,基于单位矩阵测得的传输矩阵,其聚焦点光强为背景光强的19倍;而基于哈达玛矩阵测得的传输矩阵,其聚焦点光强为背景光强的16倍。     

基于曲面空间合束的多单管半导体激光光纤耦合

随着单管半导体激光器光纤耦合技术的不断发展,为了进一步提高多单管半导体激光器的输出功率,本文采用曲面空间排列方式对多个单管半导体激光器进行合束研究,使更多数量的单管半导体激光器耦合进入同一光纤中,获得更高的输出功率。文中利用ZEMAX光学设计软件进行仿真模拟,将34只波长为975 nm、输出功率为10 W的单管半导体激光器合束聚焦后耦合进芯径200 μm、数值孔径0.22的光纤中,获得耦合效率91.76%、输出功率312.03 W的激光系统。实验中,将17只单管半导体激光器耦合进芯径200 μm、数值孔径0.22的光纤中,在10.5 A的驱动电流下,输出功率为100.5 W,系统耦合效率为68.46%。     

Potts-Ising model for simulation of polarization switching in polycrystalline ferroelectrics

This paper proposes a scheme based on the Potts and Ising models for simulating polarization switching of polycrystalline ferroelectrics using the Monte Carlo method. The polycrystalline texture with different average grain size is produced from the Potts model. Then Ising model is implemented in the polycrystalline texture to produce the domain pattern and hysteresis loop. The domain patterns and hysteresis loops have been obtained for polycrystalline texture with different average grain size. From the results of domain pattern evolution process under an applied electric field using this scheme, an extended domain, which covers more than one grain with polarization aligned roughly in the same direction, has been observed during the polarization reversal. This scheme can well reproduce the basic properties of polycrystalline ferroelectrics and is a valuable tool for exploring the physical properties of polycrystalline ferroelectrics.     

迁移率对单层有机发光器件中复合率分布的影响

以载流子运动的扩散-漂移理论为基础,利用数值方法研究了有机发光层中双极载流子注入时的电势、电场、载流子浓度和复合率分布.结果表明:当两种载流子的迁移率相同实现平衡注入,并且当空穴和电子的复合为Langevin型时,复合率的分布曲线相当理想,参与复合的空穴和电子总量远大于其他情况,由此器件的发光性能也得到更大的优化.     

沉淀方法对CeO2-ZrO2系储氧材料性能的影响

利用不同沉淀方法制备了一系列CeO2-ZrO2系储氧材料,并应用BET、XRD、TPR及其储氧性能测定等方法对储氧材料进行了研究.结果表明,不同的沉淀方法对样品的结构和性能有重要的影响.并流法可得到耐高温,储氧性能好,比表面积高的储氧材料;正滴法所得样品储氧量低但稳定,其比表面积抗老化性能差;反滴法所制备的样品储氧性能好,老化后比表面积较低.三种沉淀方法均可形成CeO2-ZrO2固溶体,材料的还原性能取决于比表面积,但与储氧性能无直接关系.     

基于纯转动拉曼谱线激光雷达的大气温度反演分析

由于气溶胶的影响,传统的瑞利散射法测量低空大气温度有一定的局限,为此开展了纯转动拉曼法测量低空大气温度。利用纯转动拉曼激光雷达在北京进行了2个月的大气温度观测,由观测数据反演了温度廓线。在基于N₂和O₂的纯转动拉曼谱线特征进行大气温度反演过程中,分析了平滑窗口、定标范围和定标常数对温度反演精度的影响。结果显示随着平滑窗口的增大,雷达和无线电探空仪测量的温度之间的平均绝对偏差先减小后增加,为有效去除信号中随机误差的影响,同时保留温度廓线的垂直结构,平滑窗口应选择600~1 200 m比较好。定标范围不同,雷达和无线电探空仪测量的温度之间的平均绝对偏差就不同,相对变化约为0.07 K。当定标常数a,b都增大或都减小时,雷达和无线电探空仪测量的温度之间的平均偏差增大,当一个增大另一个减小时,平均偏差相互抵消;a,b的变化不是等几率的,在符号上总是相反的;平均偏差对a的变化不敏感,对b的变化也不敏感,对a与b的整体变化敏感,约91.7%平均偏差落入-3~3 K之间。该研究分析结果对纯转动拉曼激光雷达数据反演中涉及的平滑窗口、定标范围的选择提供了理论依据,对激光雷达定标常数造成实际温度反演结果的误差提供了参考。     

Ferroelectric Properties of Polycrystalline Ceramics with Dipolar Defect Simulated from the Potts--Ising Model

Physical properties of polycrystailine ferroelectrics including the contributions of the fixed dipolar defects and the average grain size in the Potts-Ising model are simulated by using the Monte Carlo method. Domain pattern, hysteresis loop and switching current of the polarization reversal process are obtained. Two processes are considered in our simulation. In the first one, the grain texture of ferroelectric ceramics are produced from the Ports model, and then the Ising model is implemented in the obtained polycrystailine texture to produce the domain pattern, hysteresis loop and switching current. It is concluded that the defect has the ability to decrease the remnant polarization P~ as well as the coercive field E~. The back switching is obviously observed after the electric field is off, and it shows some variation after introducing the fixed dipolar defect. Meanwhile, the spike of the switching current is found to lower with the increasing defect concentration and the decreasing average grain size.