叶黄素简介

叶黄素属类胡萝卜素,近年研究发现其具有保护视觉、抗氧化、抗癌等作用。本文从叶黄素的结构、性质、来源、生理功效、研究现状及应用前景等方面进行了介绍。     

硬脂酸镉和山嵛酸镉混合LB膜的微结构

X-ray diffraction (XRD) was used to investigate the microstructure and phase separation of mixed multilayers of cadmium stearate (SA) and behenate (BA) deposited onto hydrophilic glass by the Langmuir-Blodgett technique. No unitary fatty acid diffraction peaks in the XRD spectra of the mixed LB films, which reveals that domains in these samples are small and uniform. The interplanar spacing of the mixed LB films changes with the ratio of BA to SA in a step-shaped curve, which suggests that with the changing of the ratio between BA and SA, only three kinds of ordered structure form in the mixed system, and each microstructure, in particular, the short chains against long chains meshed microstructure can be maintained in a certain ratio range . In addition, for the meshed microstructure, the alkyl chains of both SA and BA stand straight or may have exactly the same small tilted angle from the substrate normal, as is indicated by the symmetric and asymmetric stretching vibration of methylene (CH2) peaks which are at 2847.80 and 2914.37 cm-1respectively in the Fourier transform infrared (FT-IR) transmission spectra. The mixed system always goes through a longitudinal regularity decreasing process when BA/SA is out of the intermediate ratio range (BA/SA: 1/5-1/1), which is illustrated by the relative XRD intensity changing with the ratio of BA/ SA in a \W" shape. These results for the mixed LB films of BA/SA provide meaningful data for choosing the mixture ratio when fabricating composite films with special structure.     

Preparation and Properties of Electrospun Sheath-core Modified-PMMA Nanofibers with Photoluminescence and Photochromic Functions

Multi-functional nanofibers are playing an important role in the optical field, and are widely used in fluorescence indication, product anti-counterfeit identification and smart clothing. Nanofibers with photoluminescence and photochromic functions are already attracting more interest from researchers. In this work, based on electrospun technology, the modified-PMMA nanofibers[PMMA=poly(methyl methacrylate)] with photoluminescence and photochromic functions were prepared through the design of the sheath-core structure(SCNFs 1-4). Compared with other samples, SCNF-4 shows outstanding photoluminescence and photochromic functions. SCNF-4 can produce green light and its fluorescence intensity and fluorescence lifetime can reach 7144 a.u. and 1031.32 μs, respectively. In photochromic functions, SCNF-4 can show purple in 1 min under the 365 nm ultraviolet light, and the color can be preserved for more than 4 h under the sunlight. When SCNF-4 is irradiated by far infrared light, the color of the samples can fade quickly in 40 s. Under the irradiation of ultraviolet light of different wavelengths, SCNF-4 can display multi-color fluorescence and achieve a reversible transition between white and purple. The design of the sheath-core structure realizes the complementarity of photoluminescence and photochromic functions of the electrospun modified-PMMA nanofibers, which is important to promote the wide application of multi-functional nanofibers in the optical field.     

具有Beddington-Deangelis类功能反应的时滞食物链系统全局吸引性研究

研究了具有Beddington-Deangelis类功能反应的时滞食物链捕食者-食饵系统模型,得到了与时滞有关的系统永久持续生存的充分条件,同时通过构造Lyapunov函数得到了与时滞有关的系统全局渐近稳定的充分条件,是对文献结果的进一步推广和改进.     

孔梯度陶瓷纤维复合膜管的制备及特性

陶瓷过滤管具有孔隙率高、耐腐蚀、耐高温、机械强度高、便于清洗、使用寿命长等优点,是高温烟尘处理用的高效过滤元件.本文研制了一种具有梯度孔结构堇青石陶瓷纤维复合膜过滤元件,该过滤元件是由多孔支撑体、过渡层和分离膜层组成.其中支撑体、过渡层和分离层的气孔率分别为35～40;、50～60;和60～70;.文中主要分析了孔梯度陶瓷纤维复合膜管的材料结构和抗热震性能,同时对复合膜管进行含尘气体过滤的冷态模拟试验.对于烟气中粒径大于或等于0.1μm的颗粒,复合膜管的截留率达到99.8;以上.     

盐藻(Dunaliella viridis)细菌人工染色体文库的构建和鉴定

盐藻具有极强的耐盐能力,是研究植物耐盐机制的模式系统.为了对其耐盐机制进行深入的 研究,以pCC1BAC为载体,构建了盐藻的细菌人工染色体（BAC）文库.该文库共有9 216 个转化子,插入片段平均长度为55 kb,以单克隆形式保藏在96块96孔板中,并建立了四维P CR基因筛选体系,可以通过4轮PCR快速筛选获得阳性单克隆.根据本实验室分离到的两个盐 藻基因的cDNA序列（ DvSPT2和DvTPSP ）设计引物,通过PCR从该文库中各筛到4个阳性BA C克 隆,说明该文库能有效用于分离盐藻基因的基因组序列,据此推测该文库约覆盖4倍盐藻基 因组序列.     

磺酸型双子表面活性剂在有机硅乳液聚合中的应用

以八甲基环四硅氧烷(D4)为原料,磺酸型双子表面活性剂为乳化剂(兼催化剂),制备了一种新型的有机硅乳液.考察了反应温度、乳化剂的用量、反应时间对乳液体系的粒径、D4的转化率、黏均分子量和力学稳定性的影响.结果表明:采用单体滴加法,在85℃高温聚合8h,然后25℃低温聚合12h,乳化剂用量为单体用量的10%,在此条件下制备的产品为微透明且具有优异稳定性能的乳液,D4转化率较高,该乳液经破乳后得到的聚硅氧烷(PDMS)黏均分子量达到2.38×105g/mol.     

基于FPGA的全景图像展开算法实现

全景图像柱面展开理论算法占用系统资源较大,不适合在资源有限的嵌入式系统上实现,所以改善算法,设计一种基于嵌入式系统的算法有一定的现实意义,文中以柱面展开算法为理论依据,设计一种能在FPGA上实现的快速柱面展开算法．采用Matlab验证算法的可行性,然后采用硬件描述语言编写硬件模块,模块通过ModelSim仿真后,最终在硬件平台上实现FPGA对全景图像的快速柱面展开算法．     

藏药材红毛五加不同药用部位和不同产地茎皮中总皂苷的含量测定

目的：比较川产藏药材红毛五加不同药用部位和不同产地茎皮中总皂苷的含量．方法：采用超声法提取红毛五加总皂苷,紫外．可见分光光度法于548nm渡长处测定总皂苷的量．结果：齐墩果酸在11．8496～82．9472μg范围内呈良好的线形关系,平均回收率98．82％,RSD为1．42％（,2=9）;用此条件测得四川不同产地红毛五加茎皮中均含有总皂苷,其中以四川阿坝州大板村和四川阿坝州金川县产的红毛五加茎皮总皂苷含量较高（12．12％、10．04％）：不同药用部位中根、茎皮、叶、茎刺和去皮后的茎分别为12．90％、12．13％、7．71％、0．84％和1．88％．结论：该方法简便、快速、准确,可用于红毛五加药材质量的捡测手段之一;有关红毛五加根和叶的开发利用报道少见,从总皂苷成分和资源综合利用的角度考虑．建议根和叶可以入药．     

部分取代苯定量结构-生物降解相关性(QSBR)研究

采用Ｃｈｅｍｓ３Ｄ中量子化学ＭＯＰＡＣ－ＡＭ１法计算了７种间苯胺类和８地苯酚的分子量高占有轨道能ＥＨＯＭＯ、分子最低空轨道能ＥＬＵＭＯ。用ＱＳＡＲ程序软件包查得分子体积Ｖｍ。结合分子连接性指数（＾３Ｘ,＾３Ｘ＾ｖ）对生物降解二级速率常数对数ｌｇＫｂ进行定量结构－生物降解相关性（ＱＳＢＲ）分析,通过回归分析,得到如下两个回归方程：ｌｇＫｂ＝－０．８３２－０．１１８Ｖｍ＋１．７４８＾３Ｘ＾ｖ,ｎ＝１５,Ｒ＾２＝０．８３２,ＳＥ＝０．５７７,Ｆ＝２９．７,ｐ＝０．０００。（１）ｌｇＫｂ＝０．１２４Ｖｍ＋１．７４９＾３Ｘ＾ｖ,ｎ＝１５,Ｒ＾２＝０．９９８,ＳＥ＝０．５５９１,Ｆ＝４１４８．９９,ｐ＝０．０００．（２）