PHASE TRANSITIONS IN COLLOIDAL SYSTEMS PART I: REFRACTOMETRIC STUDY OF THE BINARY SYSTEM SDS+WATER OR PENTANOL-1+WATER AND THE TERNARY SYSTEM WATER+SDS+PENTANOL-1 AT 298.15 K.

The monophasic ranges for the binary systems water+SDS and water+pentanoM and for the ternary system water+SDS+pentanoM has been studied by means of refractametric experiments at 298 K.

The curves of refractometric index versus the composition of the system, has shown the existence of several transitions labeled successive critic micellar concentrations. These transitions are detected by a change of the variation of the refractive index.

We have evidenced the very importance of the pentanol-1 in these amphiphilic solutions, acting as a surfactant or as an oil according the concentration.

For these systems it is passible to better understand the phase inversion phenomena.

At last, we present the phase diagram indicating the concentration range of the different microstructures.     

Potential antimicrobial compounds in flower extract of Plumeria alba

This study was carried out to investigate the antimicrobial activity of methanolic flower extract of Plumeria alba and identification of the possible antimicrobial compounds through GC–MS analysis. Antimicrobial efficacy of the methanolic extract of 5 ppm to 1000 ppm concentrations was assessed against five fungal (Trichoderma viride, T. reesei, T. harzianum, T. hamatum and T. koningii) and five bacterial species (Escherichia coli, Salmonella sp., Pseudomonas sp., Bacillus sp. and Staphylococcus sp.). In general, all the concentrations of the extract significantly reduced growth of all the fungal and bacterial species. However, there was a significant variation in susceptibility of different fungal and bacterial species to the applied concentrations of the extract. The extract was the most effective against T. reesii followed by T. viride, T. harzianum, T. hamatum and T. koningii causing 11–97%, 36–90%, 24–86%, 7–77% and 9–76% reduction in their growth. Similarly, there was 23–93%, 12–92%, 36–90%, 19–90% and 8–84% reduction in growth of Bacillus sp., Staphylococcus sp., E. coli, Pseudomonas sp., and Salmonella sp., respectively, due to different concentrations of methanolic extract. GC–MS analysis of the extract showed the presence of 21 constituents. The most abundant compound was benzofuran, 2,3-dihydro- (27.95%). Other important compounds included cyclononanone (14.59%), 9-octadecyne (14.29%), 9,12,15-octadecatrienoic acid, methyl ester, (Z,Z,Z)- (10.28%), benzyl alcohol (5.57%), 1-decanol, 2-hexyl- (5.44%), 2,6-octadien-1-ol, 3,7-dimethyl-, acetate, (Z)- (3.76%), 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl- (2.48%) and heptadecane (2.43%). It is concluded that methanolic extract of P. alba flowers has the potential to control both fungal as well as bacterial growth.     

基于Flower星座的区域卫星导航系统

在Flower星座设计方法的基础上,提出了一种新的区域卫星导航系统设计方法.利用2个Flower星座,通过Flower星座模型精确计算导航Flower星座(NFC)中每个卫星的6个轨道参数,得到一个区域卫星导航系统NFC.NFC可以分阶段部署,开始由8颗卫星组成,补充发射6颗卫星以后组成完整的系统.对中国区域的几何精度因子(GDOP)仿真证明,NFC的平均GDOP值为2.113.与国内已经提出的几种区域导航系统及GPS,GLONASS,Galileo等全球卫星导航系统相比,NFC的GDOP性能与Galileo系统相当,远优于其他系统.NFC较高的导航精度和经济性证明基于Flower星座的区域卫星导航系统设计方法是有效的.     

茶树花黄酮的提取及对羟自由基的清除效果

通过对茶树花物料粒度、不同提取剂和提取方式的比较,研究茶树花黄酮的最佳提取工艺;并比较不同提取方法获得的茶树花黄酮提取物对羟自由基(·OH)的清除效果.结果表明:乙醇热回流提取的最佳工艺条件为:体积分数95%的乙醇,料液比1∶15,80℃下批次提取90 min;超声波振荡提取最佳工艺为:体积分数95%的乙醇,料液比1∶30,提取温度45℃,批次提取80 min.超声波结合热提法获得的茶树花黄酮提取物对·OH的清除效果最好.     

Effect of Flower Removal on Senescence and Metabolism of Faba Bean(Vicia Faba L.)

In pot experiments at Xichang,China,during 1989～1994,visual senescencesymptoms and associated changes in constituent contents and activities of leaves of fababean(Vicia faba L.)were compared in respones to flower removal.The leaves from upper,middle and lower positions were sampled six times during reproductive developmentphase.At 70 DAP flower removal had caused 37%～189% and 82%～197% increase ofgreen leaf area and green leaf dry weight per plant respectively.Flower removal led to asignificant increase in the chlorophyll,soluble sugar and protein contents and the catalaseactivity.The leaf cell relative electroconductivity of those plants was maintained at a lowerlevel,relative to the control,during the late growing stage.These results certainly impliedthat the leaves of flower removal plants were still fully functional at a very late growingstage,consequently the plants increased many new branches per plant.