中药青蒿化学成分的研究Ⅰ

 近年来我们对中药青篙的化学成分进行了较系统的研究,其中抗疟有效成分一青蓄素(qinghaosu)为具有过氧墓的新倍半萜内酸,有专文报道^1-4。本文报道其它倍半萜内酣,黄酮,香豆素及挥发油的分离鉴定,其中青简甲素及丙素(qinghaosu I及III)为新化合物。     

AC-PDP结构对串扰的影响

采用二维数值模拟的方法计算了表面放电型PDP在不同结构下相邻3个显示单元的放电过程.研究了放电过程中各单元内电子、氙谐振态浓度分布和其平均浓度随时间的变化情况.在流体模型计算基础上,采用蒙特卡罗模型对单元内大量谐振光子的辐射、捕获过程进行模拟跟踪,从而得出各放电单元内所产生谐振光子在荧光粉层上的分布.研究了放电过程中相邻单元之间的影响,结果表明,对传统条形障壁结构,单元内维持电极间距增大,放电空间高度增加会使放电串扰和发光串扰加强,Waffle型障壁结构不仅能提高放电效率,而且能有效阻止串扰的发生.     

聚1-[3’-(N-吡咯)丙基]-3-丁基咪唑离子液体膜电极测定双酚A

合成了1-[3＇-（N-吡咯）丙基]-3-丁基咪唑离子液体,采用电位阶跃技术制备了该离子液体聚合物膜修饰玻碳电极,利用扫描电子显微镜（SEM）和交流阻抗谱（EIS）表征了该膜修饰电极的表面形貌和电化学性能,通过伏安法研究了双酚A在该膜修饰电极上的电化学行为.结果表明：双酚A在聚离子液体膜修饰电极上只有一个不可逆氧化峰,氧化峰峰电流比在裸玻碳电极上显著增强.峰电流与双酚A浓度在1.0×10-8～1.0×10-5mol/L之间线性关系良好,检出限为8.0×10-9mol/L（S/N=3）.该法可用于测定塑料瓶中双酚A.     

基于RFID的室内智能导航系统

设计并实现了用于大规模室内环境的移动终端定位与智能导航系统.系统基于RFID技术和TDOA原理测量距离,并通过三点定位技术实现对手持移动终端的精确定位.在此基础上引入A~*搜索算法,以完成对手持终端设备准确、高效的导航.实验表明,该系统具有准确的测距与定位功能,能满足室内定位的要求.     

Effect of wing planform on leading-edge vortex structures

Flow visualization experiments are conducted in water tunnel for low aspect ratio cropped wings at low Reynolds number. The experimental results show that the model sweep angle Λ influences the formation and development of the leading-edge vortex. For wings with Λ =0°, the dominant flow structure is transverse vortex. When Λ≥26°, the dual vortex structure can be observed at some angles of attack, and it is confirmed that the dual vortex is a special structure for flow over low aspect ratio wing at low Reyno...     

Urban transport policy response to global climate change in China

Accompanying with the economic development and the process of industrialization and urbanization in China, the energy consumption and greenhouse gases emission of transport sector increased rapidly. From the viewpoint of how the urban traffic management department should cope with the global climate change, based on the economy, institutional reform, planning and policies in China, the paper analyzed the main important problems and obstacles in the development of urban transport, put forward the corresponding policy recommendations which could lead the urban transport system transform to low carbon emission and become more suitable to the climate change.     

BMSCs与PLGA支架构建组织工程化骨软骨复合组织

目的:探讨同种异体骨髓间充质干细胞(bone mesenchymal stem cells,BMSCs)体外分离培养后种植到孔径和孔隙率不同且复合不同胶原和生长因子的PLGA支架上再种植到大鼠肌袋内构建组织工程化骨软骨复合组织的可行性。方法:制作复合BMP-2和Ι型胶原PLGA支架与复合bFGF、TGF-β1和Ⅱ型胶原PLGA支架后把两者用生物蛋白胶粘合形成复合支架,把体外培养扩增的BMSCs种植到复合支架上,植入实验组A组、对照组B组、空白组C组SD大鼠肌袋内,于术后4、8、12周取材,分别行大体观察、HE染色、甲苯胺蓝染色、Ⅱ型胶原免疫组化、ALP染色、扫描电镜、透视电镜观察。结果:实验组大体标本成骨区呈白色类骨样组织,质硬,成软骨区呈乳白色类软骨样组织,质较硬,两区融合;扫描电镜观察可见成骨细胞、破骨细胞及软骨细胞,透视电镜尚可见细胞浆内有大量的线粒体和内质网,并见大量胶原分泌,与对照组、空白组有明显区别,组织学评分表明A组较B、C两组差异具有统计学意义(P0.05)。结论:BMSCs体外分离扩增后种植到孔径和孔隙率不同且复合不同胶原和生长因子的PLGA支架上再植入动物肌袋可构建骨软骨复合组织。     

Performance evaluation of the fixed relay in OFDMA systems

Performance of fixed relays in orthogonal frequency division multiple access (OFDMA) systems, especially the coverage and capacity performance at the cell edge, is evaluated in this paper.Two methods, theoretical analysis and calculation and Monte Carlo simulation, are used for the evaluations.By theoretical analysis and calculation, frequency efficiency equation of a relay is introduced and numerical results are calculated.Monte Carlo simulation results also verify that the calculation method is reasonable.The evaluation shows that a relay can increase system performance to a certain level if it is designed appropriately, otherwise it will be harmful for the system performance, even to reduce it.     

新疆基础研究现状分析

"十一五"期间,新疆经过不懈的努力,基础研究实力明显增强,研究水平不断提高,自主创新能力有了一定的提升,形成了区域研究特色,在国内外相关研究领域产生了一定影响。本文从区域创新体系出发,通过对新疆研究项目、知识创造和转移及人才培养等进行介绍,探讨了新疆基础研究现状,分析了当前新疆基础研究存在不能满足区域创新体系功能定位等问题,并提出了"十二五"改善新疆基础研究发展及资助政策的若干建议。     

Pre-desilication and digestion of gibbsitic bauxite with lime in sodium aluminate liquor

The effect of lime on the pre-desilication and digestion of gibbsitic bauxite in synthetic sodium aluminate liquor at different temperatures was investigated. The bauxite is comprised of gibbsite, aluminogoethite, hematite, kaolin, quartz, and minor boehmite. Lime increases the desilication efficiency of the bauxite during the pre-desilication process by promoting the conversion of sodalite and cancrinite to hydrogarnet. Desilication reactions during the digestion process promoted by lime result in the loss of Al₂O₃ entering the red mud, but the amount of aluminogoethite-to-hematite conversion promoted by lime leads to the increase of aluminogoethitic Al₂O₃ entering the digested liquor. The alumina digestion rate at 245℃ is higher than that at 145℃ due to the more pronounced conversion of aluminogoethite to hematite. The soda consumption during the digestion process decreases due to lime addition, especially at higher temperatures.