表面改性后的SiO2薄膜光学性能研究

用溶胶-凝胶法在酸碱复合催化条件下制备了Si O2溶胶,采用浸渍提拉法在K9玻璃上制备了性能稳定的Si O2薄膜,并用三甲基氯硅烷对Si O2薄膜进行了表面改性。用反射式椭圆偏振光谱仪测试薄膜的椭偏参数,并用Cauchy模型对椭偏参数进行数据拟合,获得了Si O2改性前后在300~700 nm波段的色散关系。讨论了薄膜改性与光学性能间的关系。结果表明:Cauchy模型能较好的描述溶胶-凝胶薄膜在300~650 nm波段的光学性能;表面改性后Si O2薄膜光学常数发生改变,但未影响色散关系的变化趋势;薄膜改性后具有随着膜层数的增加,折射率增加,而最大峰值透光率、孔隙率减小的规律,且薄膜改性后表面更加致密。     

Experimental Solution of the Local Field Problem in Uniaxial Liquid Crystals†

A method of experimental determination of the Lorentz-factor tensor in uniaxial liquid crystals is suggested. The specific features of the local field tensor of the light wave in a nematic liquid crystal with low optical anisotropy have been investigated experimentally. Anisotropy of the local field and Lorentz-factor tensors has been found to decrease with the decreasing optical and molecular-optical anisotropies. These results appear to contradict the existing polarization theories of liquid crystals. The local field problem in cholesteric liquid crystals has been considered. A new approach to the local field problem in uniaxial liquid crystals with arbitrary optical anisotropy is developed and the experimental results are explained.     

Prebiotic activity of polysaccharides extracted from Gigantochloa levis (Buluh beting) shoots

Bamboo shoot crude polysaccharides (BSCP) extracted from the shoots of Gigantochloa levis gave about 3.27 ± 0.18% on dry basis and a very minute percentage of protein (0.02 ± 0.01%). The molecular weight of BSCP estimated by gel chromatography was found to be around 7.49 × 103 Da, while the molecular weights of purified fractions (F1 to F5) were around 1550.96, 1471.63, 1685.78, 1691.61 and 1551.67 Da, respectively. The FTIR spectrum of BSCP revealed the possibility that the extract contains β-glucan, which can be considered a valuable compound for the medical and food industries. These relate to the resistance of BSCP towards artificial human gastric juice which is more than 99%. Prebiotic activity tested using BSCP as a carbon source showed significant increase in the growth of B. animalis ATCC 1053, B. longum BB 536 and L. acidophilus ATCC 4356 as compared to the use of FOS. Survivality of S. choleraesuis JCM 6977 was found to be slower in both BSCP and FOS. Study conducted reflects a good sign for the BSCP to be exploited as a promising prebiotic.     

二氢苯骈[c]菲啶类生物碱的制备及其抗乙肝病毒的活性

二氢苯骈[c]菲啶类生物碱是自然界中一类重要的生物活性成分,但含量很低.利用硼氢化还原方法,对博落回粗提物中的血根碱和白屈菜红碱混合物进行还原、分离,得到了二氢血根碱和二氢白屈菜红碱;并初步评价了其抗乙肝病毒活性.结果表明,利用硼氢化还原方法制备二氢苯骈[c]菲啶类生物碱的产率较高,还原产物具有一定的抗乙肝病毒活性.     

SOME GEOMETRIC PROPERTIES OF A NEW DIFFERENCE SEQUENCE SPACE INVOLVING LACUNARY SEQUENCES

In this paper, we define a new generalized difference sequence space involving lacunary sequence. Then, we examine k-NUC property and property （β） for this space and also show that it is not rotund where p = （pr） is a bounded sequence of positive real numbers with pr ≥ 1 for all r ∈ N.     

一种分析自由电子激光场的新量子方法

将固体理论中的LLP变换用于研究自由电子激光场的量了态,并求得了小信号增益,这种新方法简捷且有助于深入地探讨自由电子激光场的量子特性. 关键词：     

蛙峡核的视野区域对应投射和双眼反应

本文用玻璃微电极从黑斑蛙(Rana nigromaculata)左峡核细胞外记录了125个单位的视觉反应,并用钴染色法标记出101个电极尖端位置,以便重建峡核内的视野图。在所记录的单位中,80％对静止光点显示给光(ON)-撤光(OFF)反应,许多单位对通过其感受域的黑、白目标的运动有方向选择性。所有钴标记点都在核内,表明峡核本身是蛙视觉系统的一个局限部分。在峡核内有一个视野投射圈。整个对侧半视野和同侧半视野的鼻侧40°呈区域对应地投射到峡核上。核内的无细胞带是对侧半视野与同侧半视野的分界线,它的背侧是对侧视野代表区。上视野投射到核的嘴半部、尾半部的中央和内腹部分。下视野的代表在尾半部的背部和外侧部。在峡核里观察到15个双眼单位,其中13个主要被对侧眼兴奋,2个几乎同等地被两只单眼兴奋。标记成功的14个双眼单位主要位于峡核嘴半部的髓质内。     

高校图书馆书刊采访决策支持系统

在指出高校图书馆书刊采访科学决策重要性的基础上,分析影响书刊采访决策的基本因素,提出一种科学的书刊采访决策模式.建立了图书供应商选择、采购经费分配、书刊选购决策的数学模型,进而给出书刊采访决策支持系统的设计方案.该系统的应用可提高图书采访质量.     

瞬态光谱测试仪在烟火方面的应用

用３５０～１１００ｎｍ瞬态光谱测试仪对烟火药剂进行谱测试，分析碱金属和碱土金属在烟火药火焰光谱中的辐射波段，计算各红外烟火剂的稳身指数。