基于SBS光限幅和金属酞菁光限幅相结合的复合型光限幅器的研究

为了使受激布里渊散射(SBS)光限幅器的输出能量更"平",提出了一种基于SBS光限幅和金属酞菁光限幅相结合的复合型光限幅器的方案,即SBS光限幅后边放置金属酞菁光限幅,在两种光限幅器的共同限幅作用下,使复合型光限幅器的输出光能量更"平". 数值模拟了该复合型光限幅器的输出光能量随入射光强度的变化曲线,并在Countinuum's Nd: YAG种子注入式激光器中进行了实验验证. 理论和实验结果均表明,复合型光限幅器的输出光能量比单独SBS光限幅器更"平". 关键词： 复合型光限幅器 SBS光限幅 金属酞菁限幅     

ON THE INVERTIBILITY OF HILBERT SPACE IDEMPOTENTS

This note is to present some results on the group invertibility of linear combina- tions of idempotents when the difference of two idempotents is group invertible.     

主客观组合赋权的灰色决策模型及其在消费者决策中的运用

现实中许多抽象系统的数值并不能精确地得到,在多属性决策过程中,其属性值多以模糊数或者区间灰数的形式表示,属性权重也受到主观因素和客观因素的影响,针对此类问题,以属性值为区间灰数的多属性决策问题为出发点,采用主客观结合的赋权方式,提出了基于区间距离的灰色相对关联度分析方法,构建了灰色决策模型,并通过消费者决策实例进行了分析,模型是对传统灰色决策模型的拓展,具有更广泛的应用性和实用性.     

On-line combination of single-drop liquid–liquid–liquid microextraction with capillary electrophoresis for sample cleanup and preconcentration: A simple and efficient approach to determining trace analyte in real matrices

In order to improve the sensitivity of capillary electrophoresis (CE) and overcome the deficiency of commercial CE instruments in handling complex matrices directly, we proposed a novel technique which combined single-drop liquid–liquid–liquid microextraction (SD-LLLME) with CE on-line. In this technique, SD-LLLME was realized using a commercial CE instrument and, to further concentrate the target analyte, large-volume sample stacking combined sweeping without polarity switching was utilized. Even though without agitating the donor phase in the extraction process, the model compound, adenine was enriched 550-fold in only 10 min. The enrichment factors were 760 and 1030 when the extraction time was extended to 30 and 60 min, respectively. The relative standard deviations (RSDs) of adenine were 5.24% and 2.29% for peak area and migration time, respectively, which indicated that this method was much more reproducible compared to the existing methods that combined sample-preparation strategies with CE. In addition, this approach was selective while cleaning up target analyte. These mentioned advantages allowed the developed method to be an attractive approach to determining trace target compounds in complex real samples.     

Assessment of conservative weighting scheme in simulating chemical vapour deposition with trace species

Low‐pressure or ultra‐high vacuum chemical vapour deposition often involves important trace species in both gas‐phase and surface reactions. The conservative weighting scheme (J. Thermophys. Heat Transfer 1996; 10 (4) : 579) has been used to deal with the trace species often involved in some non‐reactive physical processes, which is otherwise considered computationally impossible using the conventional DSMC method. This conservative weighting scheme (CWS) improves greatly the statistical uncertainties by decreasing the weighting factors of trace‐species particles and ensures the conservation of both momentum and energy between two colliding particles with large difference of weighting factors. This CWS is further extended to treat reactive processes for gas‐phase and surface reactions with trace species, which is called extended conservative weighting scheme (ECWS). A single‐cell equilibrium simulation is performed for verifying both the CWS and ECWS in treating trace species. The results of using CWS show that it is most efficient and accurate for weight ratio (trace to non‐trace) equal to or less than 0.01 for flows with two and three species. The results of a single‐cell simulation using ECWS for gas‐phase reaction and surface reactions show that only ECWS can produce acceptable results with reasonable computational time. Copyright © 2003 John Wiley & Sons, Ltd.     

次序统计量线性函数的随机加权逼近速度

设ｘ１，ｘ２，…ｘｎ（连续未知），Ｆｎ为经验分布函数，Ｈｎ（ｘ）为随机加权经验分布函数，。ｘｎ１≤ｘｎ２≤…≤ｘｎｎ为次序统计量．记以Ｆｎ取代σ２（Ｊ，Ｆ）中的Ｆ即得σ２（Ｊ，Ｆｎ）．     

一个分析不等式的反向

本文建立了作者在１９９０年证明的一个分析不等式的反向形式；作为其直接推论，我们得到了Ｊａｎｏｕｓ－Ｋｌａｍｋｉｎ猜想（１９９２年）等一系列有意义的结果。     

一类Bernstein型算子线性组合加Jacobi权的逼近

给出了一类用广义杨辉三角阵定义的Bernstein型算子线性组合加Ja-cob i权的逼近在一致逼近意义下的特征刻划.     

基于预测有效度的组合预测方法冗余信息的判定

基于预测方法有效度的概念 ,建立了考虑预测精度标准差的预测有效度的组合模型 ,提出了几个新的概念 ,给出冗余信息出现的两个判定定理 .并用实例说明判定定理的有效性 .     

基于对数灰关联度的加权几何平均组合预测模型的有效性

基于对数灰关联度的加权几何平均组合预测是一种新的非线性组合预测。针对该方法提出新的优性组合预测、预测方法优超、冗余度等概念,给出优性组合预测存在的充分条件,最后证明冗余预测方法的一个判定定理。