随着控制释药技术的不断提高,及至90年代,多层片释药系统(multiple layer tablet as drug delivery system)越来越受到重视。该系统是在骨架片的基础上发展的一种多相释药系统,它由含有药片心及一层或多层屏障层(barri-ers)组成,屏障层...随着控制释药技术的不断提高,及至90年代,多层片释药系统(multiple layer tablet as drug delivery system)越来越受到重视。该系统是在骨架片的基础上发展的一种多相释药系统,它由含有药片心及一层或多层屏障层(barri-ers)组成,屏障层作为释药调节层,通过减少药物的释放表面积及限制溶剂的渗透速度,延缓溶出介质对片心的作用,达到控制释放的目的。片心有骨架缓释型及速释型,外层阻滞层对心片进行一层或上下两层覆盖、周边覆盖或阻滞层压制包裹片心形成包心片(press coated tablet)。这种技术可针对药物不同的溶解特性及生物学特征,对药物的释放作更为精细的调节以满足各种需要,包括不同性质的复方药物在同一系统中的释放调节。阻滞层可根据药物性质特性选用溶解性、膨胀性的高分子聚合物或生物可降解物质。展开更多
In this paper, we propose a new two-lane cellular automata model in which the influence of the next-nearest neighbor vehicle is considered, The attributes of the traffic system composed of fast-lane and slow-lane are ...In this paper, we propose a new two-lane cellular automata model in which the influence of the next-nearest neighbor vehicle is considered, The attributes of the traffic system composed of fast-lane and slow-lane are investigated by the new traffic model. The simulation results show that the proposed two-lane traffic model can reproduce some traffic phenomena observed in real traffic, and that maximum flux and critical density are close to the field measurements. Moreover, the initial density distribution of the fast-lane and slow-lane has much influence on the traffic flow states. With the ratio between the densities of slow lane and fast lane increasing the lane changing frequency increases, but maximum flux decreases. Finally, the influence of the sensitivity coefficients is discussed.展开更多
文摘随着控制释药技术的不断提高,及至90年代,多层片释药系统(multiple layer tablet as drug delivery system)越来越受到重视。该系统是在骨架片的基础上发展的一种多相释药系统,它由含有药片心及一层或多层屏障层(barri-ers)组成,屏障层作为释药调节层,通过减少药物的释放表面积及限制溶剂的渗透速度,延缓溶出介质对片心的作用,达到控制释放的目的。片心有骨架缓释型及速释型,外层阻滞层对心片进行一层或上下两层覆盖、周边覆盖或阻滞层压制包裹片心形成包心片(press coated tablet)。这种技术可针对药物不同的溶解特性及生物学特征,对药物的释放作更为精细的调节以满足各种需要,包括不同性质的复方药物在同一系统中的释放调节。阻滞层可根据药物性质特性选用溶解性、膨胀性的高分子聚合物或生物可降解物质。
基金The project partly supported by the National 0utstanding Young Investigation under Grant No. 70225005 of National Natural Science Foundation of China, National Natural Science Foundation of China under Grant No. 70471088, and the Teaching ＆ Research Award Program for 0utstanding Young Teachers in Higher Education Institutions （2001） of the Ministry of Education of China
文摘In this paper, we propose a new two-lane cellular automata model in which the influence of the next-nearest neighbor vehicle is considered, The attributes of the traffic system composed of fast-lane and slow-lane are investigated by the new traffic model. The simulation results show that the proposed two-lane traffic model can reproduce some traffic phenomena observed in real traffic, and that maximum flux and critical density are close to the field measurements. Moreover, the initial density distribution of the fast-lane and slow-lane has much influence on the traffic flow states. With the ratio between the densities of slow lane and fast lane increasing the lane changing frequency increases, but maximum flux decreases. Finally, the influence of the sensitivity coefficients is discussed.
