Er,Yb：(LaLu)2O3透明陶瓷制备及上转换发光性能

采用柠檬酸燃烧法制备Er,Yb：（LaLu）₂O₃陶瓷粉体,用X射线衍射对其进行了物相鉴定,研究表明1 000℃时已经得到纯相的（LaLu）₂O₃。采用冷等静压-真空烧结法制备了Er,Yb：（LaLu）₂O₃和Er：（LaLu）₂O₃陶瓷,对陶瓷的结构和光谱性能进行了详细的研究,研究发现掺杂5% Yb³⁺和10% La³⁺样品的上转换发光强度与未掺Yb³⁺、La³⁺样品相比明显增大,根据上转换光谱显示较强发射峰位于564 nm和661 nm处,对应Er³⁺的⁴S_3/2（²H_11/2）→⁴I_15/2能级跃迁和⁴F_9/2→⁴I_15/2能级跃迁,并讨论了Er³⁺-Yb³⁺的能量传递过程及其上转换发光机制。     

直接序列扩频系统中数字Costas环的设计与实现

主要针对直接序列扩频系统(DSSSS)的载波同步,研究了数字Costas环的设计和实现方法.介绍了数字Costas环的结构和其提取载波频率和相位、实现载波同步的基本原理.以典型的二阶连续系统的离散数字化方法为基础,分析了线性数字锁相环(DPLL)的参数设计方法,为非线性的数字Costas环的设计提供了参考.提出了一种在高速数字信号处理器(DSP)中数字Costas环的软件实现方案;经过试验验证,能够实现载波同步,并且应用更加简单、灵活,性能更加稳定.     

长链氨羧络合剂萃取稀土饵

研究了长链氨羧络合剂N,N′-二(十二烷基)乙二胺二乙酸钠(Na2R2Y)的氯仿溶液萃取稀土饵的行为;考察了溶液酸度、络合剂浓度、相比和温度对萃取率的影响.用摩尔比法测定了Na2R2Y与Er3+的络合摩尔比为1∶1;结果表明,Na2R2Y的氯仿溶液对饵的萃取率随络合剂浓度的增大而增大,随温度的升高而降低.     

Complex lanthanide chromate(VI)-phosphates K2R(CrO4)(PO4) (R = Dy-Lu, Y)

The conditions of formation of complex lanthanide chromate(VI)-phosphates K₂R(CrO₄)(PO₄) were found and these compounds were synthesized by solid-state synthesis with variation of the starting compounds, the temperature of synthesis (500–800 °C), and the annealing time (6–200 h). These salts are typical of late lanthanides, R = Dy-Lu, Y. Using lutetium derivatives as examples, it was shown that no similar compounds with lithium or sodium are formed. All the complex chromate(VI)-phosphates obtained decompose under static conditions at temperatures above 550 °C. They are isostructural and crystallize in the monoclinic system. The unit cell parameters for thulium, ytterbium, and lutetium compounds were calculated. It is shown by IR spectroscopy that PO₄ tetrahedra in the crystal lattice of potassium lanthanide chromate(VI)-phosphates are substantially distorted, whereas the CrO₄ tetrahedra retain the regular tetrahedron symmetry (T _d ). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 622–626, April, 2006.     

增益介质的色散对锁模激光器输出脉宽和啁啾的影响

利用时间域内各光学元件的传播矩阵,在考虑了增益介质的色散后,对锁模激光器输出的脉宽和啁啾做了理论方面的推导,并做了相关的数值模拟,结果表明:当不考虑增益介质的色散时,其输出脉宽啁啾值为零;而考虑了增益介质的色散后,啁啾值随色散值的增加先增加而后降低,且存在一个最大值,脉宽随色散值的增加而增加.     

锁相环的相位模型与实验电路

讨论了锁相环的相位数学模型,给出了一种适合于数学的锁相环实验电路．     

量热法研究氯化铒与甘氨酸配合物的标准生成焓

量热法测定;量热法研究氯化铒与甘氨酸配合物的标准生成焓     

Asymmetric cycloaddition of β,γ-unsaturated α-ketoesters with electron-rich alkenes catalyzed by a chiral Er(OTf)3/N,N'-dioxide complex: highly enantioselective synthesis of 3,4-dihydro-2H-pyrans

The asymmetric inverse-electron-demand hetero-Diels-Alder (HDA) reactions of β,γ-unsaturated α-ketoesters with electron-rich alkenes were investigated, with an N,N'-dioxide/erbium(III) complex employed as the catalyst. Quantitative conversion of the β,γ-unsaturated α-ketoesters and excellent enantioselectivities (up to >99% ee) and diastereoselectivities (up to >99:1 d.r.) were observed for a broad range of substrates by using a 0.5-0.05 mol% catalyst loading under mild reaction conditions. The reaction could be scaled up to the gram scale with the same results. In addition, this was the first application of Er(OTf)(3) to the asymmetric inverse-electron-demand HDA reaction and it behaved as an efficient catalyst. Moreover, the synthetic utility of this methodology was demonstrated with the synthesis of key intermediates of some natural products.     

7.13 W全固态1 319 nm宏微脉冲激光器

研制了一台高效率全固态平均功率7.13 W的1 319 nm宏微脉冲激光器。激光器采用热稳Z形折叠腔,增益模块采用自行研制的准连续15个二极管芯片环形泵浦的Nd:YAG模块,采用主动声光锁模器作为锁模元件,并在腔内插入倍频KTP晶体对激光器的输出尖峰进行抑制。为了获得稳定的锁模状态,对激光器腔长进行了精确设计和调节。当激光器腔长与锁模器驱动频率匹配时,获取了宏脉冲重复频率400 Hz、脉宽约190 μs,微脉冲重复频率95.6 MHz、脉宽小于1.0 ns的1 319 nm激光脉冲。     

Application of experimental design for optimization of erbium determination by high-resolution continuum source electrothermal atomic absorption spectrometry using lanthanum as a chemical modifier

ABSTRACT

In this paper, lanthanum was used as a chemical modifier for the direct determination of erbium by high-resolution continuum source electrothermal atomic absorption spectrometry. A two-step experimental design was used for optimization, first a full factorial design was conducted for identification of significant factors, and then a central composite design was carried out for final optimization of the significant factors. The optimum parameters were obtained as follows: atomization temperature of 2500°C, pyrolysis temperature of 1600°C, and pyrolysis time of 10?s in the presence of lanthanum as a chemical modifier. Under optimum conditions, the characteristic mass, limit of detection, and limit of quantification were 29?pg, 0.71, and 2.4?µg?L^?1, respectively. The precision of the method, estimated as the relative standard deviation for 10 replicate measurements of 50?µg?L^?1 of erbium, was 1.8%. The optimized method was applied to determine erbium content in sediments and rock samples. The determined values of erbium in sediment certified reference materials were in satisfactory agreement with the certified values according to the t-test for a 95% confidence level.