体积相位全息光栅的设计与制备

本文指出全息干版薄膜在曝光后处理过程中的收缩性和折射率变化对制备全息光栅的周期、倾斜度、布喇格入射角及衍射角的影响问题,并根据实验数据对光栅设计进行修正,再结合Kogelnik衍射方程及折射率调制度和曝光量的线性关系,在实验中基本上能准确设计出指定周期、倾斜度和衍射效率的全息光栅。     

二甲亚砜硝酸钇的晶体结构

二甲亚砜硝酸钇Y(NO₃)₃·3DMSO晶体属单斜晶系,a=13.604(4)?,b=12.669(4)?, c=11.554(2)?, β=100.14(4)°,z=4。空间群为P2₁/n。用PW-1100四圆衍射仪收集强度数据,独立衍射点数为3615个。结构已用重原子法解出,用全矩阵和方块对角矩阵最小二乘方法修正结构参数,最后R因子为0.080。结构分析结果表明,围绕着钇离子的九个氧构成稍歪扭的“三帽三方棱柱”配位多面体。钇和配位氧之间 关键词：     

风沙冲击作用下钢结构表面涂层与基体界面应力研究

在应用接触力学分析风沙冲击钢结构表面涂层的动力基础上,应用界面力学镜像点法分析涂层基体界面应力,并计算分析风沙冲击作用下涂层与钢结构界面应力。分析结果表明：界面正应力随着冲击速度的增大而增大,界面正应力在冲击点附近较大,越远离冲击点越小,在冲击点处,界面正应力随着冲击角度的增大而增大,90°时达到最大,当离冲击点有一定距离时,界面正应力在45°时达到最大。界面剪应力也随着冲击速度的增大而增大,且界面剪应力在冲击角度为30°时达到最大值,界面剪应力在离冲击点距离x=1mm的界面处,界面剪应力达到最大值,当x≤1mm时,界面剪应力随着x的增大而增大,当x＞1mm时,界面的剪应力随着x的增大而减小。     

样品表面近红外光谱结合多类支持向量机快速鉴别枸杞子产地

采用便携式近红外光谱仪采集枸杞子表面不同部位的近红外漫反射光谱,结合多类支持向量机算法对枸杞子产地进行快速无损辨识。以识别率为评价指标进行光谱预处理方法的选择,为了消除样本划分偏性对结果的影响,本研究通过重复划分样本集多次建模与预测,利用识别率的统计结果考察各个光谱采集部位的建模结果。实验结果表明,原始数据经二阶导数加SG平滑处理后,所建模型具有良好的产地预测性能。除了枸杞子顶端部位外,其他部位模型的稳定性及准确性均较好,其外部验证识别率的中位数与平均值均大于97%。这表明利用枸杞子样品表面近红外光谱可实现产地的准确鉴别,便携式近红外光谱技术可作为中药材流通环节中的有效监控手段。     

基于实时操作系统的光电稳定自适应模糊PI复合控制方法研究

针对经典稳定控制理论存在超调与快速性之间难以调和的矛盾,建立了稳定控制系统数学模型,采用自适应模糊实现控制的快速性,用PI保证系统的稳态精度,以误差为模糊控制的输入,设计一种实用的自适应模糊和PI复合控制系统,并在基于VxWorks实时操作系统的数字平台上得以实现.仿真和试验表明:设计的新型自适应模糊PI复合控制系统超调量为0,调节时间约8 ms,带宽约29 Hz.     

ZnO-SnO_2透明导电薄膜的制备及性能研究

采用二步成胶工艺制备ZnO-SnO_2透明导电薄膜,应用X射线衍射、原子力显微镜、紫外-可见分光光度计、薄膜分析仪及四探针仪等对薄膜的结构、表面微观形貌、透过率和导电性能进行表征.结果表明,锌锡摩尔比为9/12,退火温度为500 ℃时,薄膜的透过率达90%,电阻率为3.15×10~(-3) Ω·cm.与其它工艺相比,二步成胶工艺所制备出的ZnO-SnO_2透明导电薄膜性能优异.     

从极优基未必能迅达最优基：兼与文献[1]作者商榷

本对献[1]提出的“求解线性规划的快速换基迭代法”从多阶段决策的观点阐述并举证了从极优基未必能快速到达最优基的论断。旨在说明用此方法求解一般线性规划问题时不一定能实现快速换基迭代的概念。     

First-Principles Study of Structural and Electronic Properties of Layered B2CN Crystals

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.     

凝胶-燃烧法合成YAG∶Eu3+纳米荧光材料的结构和发光性能

Y₃Al₅O₁₂∶Eu nanophosphors were synthesized by a gel combustion method. The structure of phosphors was characterized by XRD and FTIR. YAG phase came to occur when YAG∶Eu precursors were sintered at 800 ℃, although the phase was mainly amorphous. The organic groups pyrolyzed completely and pure YAG phase was obtained in the samples sintered at 900 ℃. In the formation of YAG phase, no intermediate phases such as YAP and YAM were detected. Both ⁵D₀ → ⁷F₁ orange and ⁵D₀ → ⁷F₂ red emission could be observed for all the sintered samples. However, the emission of amorphous samples was greatly different from that of crystalline ones. The former was mainly ⁵D₀→ ⁷F₂ red emission, but the latter was ⁵D₀ → ⁷F₁ orange emission. As sintering temperature rises, the ratio of orange to red for phosphors increases. Eu could be doped up to 8% in YAG host lattice, and fluorescence quenching was absent. It indicated that the gel combustion synthesis method can increase emission intensity and quenching concentration due to a good distribution of Eu³⁺ activators in Y₃Al₅O₁₂ matrix.     

全自动红外测油仪的研制

研制新型全自动红外测油仪。通过对进样系统、萃取系统、吸附过滤系统和检测系统自动化和集成化设计,实现了对水中油分的全自动检测。仪器的测量范围为0～200 mg/L。自动进样器取样体积误差在1%以内,仪器示值误差在样品浓度不大于10 mg/L时为0.1 mg/L,样品浓度大于10 mg/L时为0.9%,仪器重复性为0.2%(n=6),零点漂移为–0.1 mg/L,示值漂移为0.6%,最小检出浓度为0.1 mg/L,两种水样测量结果的相对标准偏差分别为1.28%和0.91%(n=11),加标回收率分别为96.8%和96.1%,检出限为0.006 mg/L。该仪器测量准确,性能稳定,能够降低工作强度,提高工作效率,减少有机物危害,为环境监测提供有效保障。