Ashing and microwave digestion of aerosol samples with a polypropylene fibrous filter matrix

Radionuclide monitoring is one of the key techniques required by the International Monitoring System (IMS) and On-Site Inspection (OSI) in the Comprehensive Nuclear Test Ban Treaty (CTBT). There shall be a global network of 80 radionuclide monitoring stations. Atmospheric aerosols are collected generally on filters in the stations. A polypropylene (PP) fibrous filter is often used in sampling atmospheric aerosols. There might be much information to be obtained by measuring aerosol samples after digestion rather than nondestructive analysis directly by γ-spectrometry. The present work focused on pretreatment of the filter samples, which includes the influence of different ashing or microwave digestion conditions on the recoveries of analytes. The inductively coupled plasma-atomic emission spectrometric detection results indicated that the recoveries of elements in the PP fibrous filters by ashing were influenced by ashing time, temperature and the properties of the elements. High recoveries of volatile elements and consistent recovery for other elements were obtained by using a closed microwave system to digest the filters. Higher sensitivity was also obtained when the intercomparison sample was measured by a HPGe well detector after pretreatment by the recommended ashing and microwave digestion procedures.     

亚波长介质光栅导模共振研究

从平板波导的本征值方程出发,导出弱调制介质光栅共振位置的表达式,其预测结果与利用严格的耦合波理论所得值一致.对正入射时导模共振产生双反射峰现象进行解释,并就导模共振对入射角和光栅周期敏感性的成因进行了探讨.从薄膜的特征矩阵方程出发,在理论上分析了利用导模共振获得性能良好的反射滤光片的途径.     

一维参数化正交小波滤波器的解析性质与优化逼近

本文给出了一维参数化正交小波滤波器系数向量的解析表达式和它的递推计算公式,还给出了它的一阶变分及二阶变分公式．利用这些结果和最优化方法,给出了FIR正交小波滤波器的逼近和设计问题的优化模型和数值例子．     

分散液液微萃取-在线衍生化-气相色谱-质谱联用法检测环境水样品中紫外吸收剂

建立了分散液液微萃取（dispersive liquid-liquid microextraction,DLLME）-在线衍生化-气相色谱-质谱（GC-MS）方法,将其用于环境水中6种二苯甲酮类紫外吸收剂（BPs）（二苯甲酮、2,4-二羟基二苯甲酮、2-羟基-4-甲氧基二苯甲酮、4-羟基二苯甲酮、2-羟基-4-辛氧基二苯甲酮、2,2'-二羟基-4,4'-二甲氧基二苯甲酮）的检测。系统优化了在线衍生化的条件（如进样口温度、不分流时间、衍生化试剂用量）以及DLLME萃取条件（如萃取剂种类、分散剂种类、萃取剂与分散剂比例、样品体积、样品溶液离子强度及pH值）等。在最优的条件下,所考察的6种BPs检出限为0.011~0.15 μg/L,重现性（RSD）为0.7%~16.6%。该方法结果准确可靠,操作简单,富集效果好,成本较低,环境友好,在实际样品检测中具有一定的应用前景。     

Evaluation of Two Novel Hydantoin Derivatives Using Reconstructed Human Skin Model EpiskinTM: Perspectives for Application as Potential Sunscreen Agents

This study aimed to assess two novel 5-arylideneimidazolidine-2,4-dione (hydantoin) derivatives (JH3 and JH10) demonstrating photoprotective activity using the reconstructed human skin model Episkin^TM. The skin permeability, irritation, and phototoxicity of the compounds was evaluated in vitro. Moreover, the in vitro genotoxicity and human metabolism of both compounds was studied. For skin permeation and irritation experiments, the test compounds were incorporated into a formulation. It was shown that JH3 and JH10 display no skin irritation and no phototoxicity. Both compounds did not markedly enhance the frequency of micronuclei in CHO-K1 cells in the micronucleus assay. Preliminary in vitro studies with liver microsomes demonstrated that hydrolysis appears to constitute their important metabolic pathway. Episkin^TM permeability experiments showed that JH3 permeability was lower than or close to currently used UV filters, whereas JH10 had the potential to permeate the skin. Therefore, a restriction of this compound permeability should be obtained by choosing the right vehicle or by optimizing it, which should be addressed in future studies.     

Programmable phase-mostly holograms and correlation filters

We obtain continuous phase modulation with commercial twisted nematic liquid television. We present theory and experimental implementation of kinoforms, matched spatial filters, circular harmonic filters and synthetic discriminant functions with the phase-mostly filter approach.     

On the design and performance of printed-circuit filters and diplexers for millimeter-wave integrated circuits

This paper describes the design and performance of various millimeter-wave printed-circuit filters and diplexers. These components include microstrip/suspended stripline and finline lowpass filters, capacitive-gap and inductive-iris-coupled bandpass filters, spurline bandstop filters, and finline diplexers. State-of-the-art performances from Ka-band (26.5 to 40 GHz) to D-band (110 to 170 GHz) have been obtained. Agreement between the measured and calculated results was also achieved.     

Decomposability of free Łukasiewicz implication algebras

?ukasiewicz implication algebras are {→,1}-subreducts of Wajsberg algebras (MV-algebras). They are the algebraic counterpart of Super-?ukasiewicz Implicational logics investigated in Komori, Nogoya Math J 72:127–133, 1978. The aim of this paper is to study the direct decomposability of free ?ukasiewicz implication algebras. We show that freely generated algebras are directly indecomposable. We also study the direct decomposability in free algebras of all its proper subvarieties and show that infinitely freely generated algebras are indecomposable, while finitely free generated algebras can be only decomposed into a direct product of two factors, one of which is the two-element implication algebra.     

Generating ultrafilters in a reasonable way

We continue investigations of reasonable ultrafilters on uncountable cardinals defined in Shelah [8]. We introduce a general scheme of generating a filter on λ from filters on smaller sets and we investigate the combinatorics of objects obtained this way. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Hepatic CT image retrieval based on the combination of Gabor filters and support vector machine

Content-based image retrieval has been an active area of research for more than ten years.Gabor schemes and support vector machine (SVM) method have been proven effective in image representation and classification. In this paper,we propose a retrieval scheme based on Gabor filters and SVMs for hepatic computed tomography (CT) images query.In our experiments,a batch of hepatic CT images containing several types of CT findings are used for the retrieval test.Precision comparison between our scheme and existing methods is presented.