Complexation of macroporous amphoteric cryogels based on N,N‐dimethylaminoethyl methacrylate and methacrylic acid with dyes,surfactant, and protein

Macroporous amphoteric cryogels based on N,N‐dimethylaminoethylmethacrylate and methacrylic acid p(DMAEM‐co‐MAA) crosslinked by N,N′‐methylenebisacrylamide (MBAA) were synthesized by radical copolymerization of monomer mixtures in cryoconditions. The structure and morphology of cryogels were evaluated by FTIR and SEM. Cryogels exhibited interconnected porous structure with pore size ranging from 40 to 80 µm, which depended on their crosslinking degree. The value of the isoelectric point (IEP) of equimolar amphoteric cryogel determined from the water flux was equal to 4.4, while the IEP of cryogel with the excess of DMAEM units was equal to 7.1. The mechanical strength of equimolar amphoteric cryogels increases with increasing amount of crosslinking agent. The complexation ability of amphoteric cryogels with respect to surfactant, dyes, and protein was demonstrated. The adsorption isotherms with respect to anionic surfactant—sodium dodecylbenzene sulfonate (SDBS) and protein—lysozyme correspond to Langmuir equation, while adsorption isotherms of anionic and cationic dyes—methylene blue (MB) and methyl orange (MO) are well described by Freundlich equation. It was found that the binding ability of p(DMAEM‐co‐MAA) with respect to various low‐ and high‐molecular weight compounds changes in the following order: SDBS > lysozyme ? MO > MB. The preferential adsorption of MB from the mixture of protein and MB was shown. The quantitative release of protein, surfactant and dye molecules from the matrix of cryogels takes place at the IEP of cryogel. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43784.     

维吾尔语三音节词中元音和谐的声学特征分析

该文从提高语音合成自然度的实际需求出发,首次从实验语音学的角度从《维吾尔语语音声学参数库》中统计出了333个三音节词,其中再筛选了93个全和谐词和半和谐词,并对其元音的宽带共振峰模式、共振峰值、音高、时长和音强等韵律参数进行了统计分析,归纳了其共振峰、音高、时长和音强分布特点来考察元音和谐的基本声学特征,总结出了一些重要的规则和结论,为参数式或波形拼接式语音合成系统中调整合成前的元音和谐问题提供了重要的参考依据。     

不同水平的普通话学习者单字调声调感知研究

首先采用实验语音学的理论和方法进行比较分析,进一步了解普通话学习者声调学习的情况,通过定量研究的方法,对两种不同水平(高级水平和初级水平)学习者的声调感知进行声学分析并对学习普通话过程中的语调掌握状况展开探讨。考察了20名不同水平学习者对普通话声调学习的感知情况。按学习者对汉语9个单元音的4个声调感知和12个复合元音的4个声调的单字调辨认,以及阳平-上声的区分实验数据,统计学习者的辨认准确率、各调类的偏误率和反应时间,最后利用SPSS数据分析软件从统计的角度进行了辨认准确率和反应时间的相关性分析,分别对声调感知的准确率和反应时间的显著性差异进行检验。     

非汉语母语者的普通话元音和辅音感知研究

语音感知研究是语音学主要研究内容之一。为了解学习者对普通话元音和辅音的感知情况,并为汉语教学提供借鉴,拓宽言语学习模型的应用领域,减少教学的盲目性,根据第二语言习得理论模式,采用实验语音学和统计学的方法,设计辨认实验和区分实验,分别对普通话水平处于高级和初级水平的20名维吾尔族大学生元音、塞音、擦音和塞擦音的感知情况进行研究。辨认实验考察学习者对元音和辅音的感知反应时间和感知准确率。在区分实验中,计算元音对的频谱距离,辅音对的频谱距离,以及它们的时长差异,对学习者的区分能力进行分析。实验结果显示高级水平学习者的感知元音和辅音的能力明显高于初级水平学习者。学习者对发音部位靠后的元音反应时间快且感知准确率高,对于发音部位靠前的元音反应时间较慢且感知准确率低,对塞擦音的辨认准确率高,对擦音的辨认准确度最低。元音对的频谱距离和辅音对的时长差异会影响到学习者的区分能力,但辅音对的频谱距离和区分情况不存在密切联系。     

Electrostatic mirror objective with eliminated spherical and axial chromatic aberrations

Computational formulae for the coefficients of the third-order spherical aberration and the second-order axial chromatic aberration are presented for an axially symmetric electrostatic electron mirror. A technique for eliminating the high-order derivatives of the potential axial distribution in mirror systems from the integrands is described. Conditions for elimination of spherical and axial chromatic aberrations, either separately or simultaneously, are found for a three-electrode axially symmetric mirror composed of coaxial cylinders of the same diameter. A principal scheme of the transmission electron microscope, where an electrostatic electron mirror serves as its objective, is presented.