A STUDY OF STRUCTURE AND PROPERTY CHANGES OF BIODEGRADABLE POLYGLYCOLIDE AND POLY(GLYCOLIDE-co-LACTIDE)FIBERS DURING PROCESSING AND IN VITRO DEGRADATION

Structure and properties of bioabsorbable polyglycolide (PGA) and poly(glycolide-co-lactide) (PGA-co-PLA)fibers were investigated during several industrial processing stages and in vitro degradation by means of wide-angle X-raydiffraction (WAXD), dynamic mechanical analysis (DMA) and mechanical property tests. In the orientation stage, the PGAfibers were found to have higher degrees of crystallinity than corresponding PGA-co-PLA samples produced under similarconditions. In the hot-stretching and post-annealing stages, after fibers were braided, PGA samples were found to gain morecrystallinity and higher T_g than PGA-co-PLA samples. The higher crystallinity in PGA fibers resulted in a slower rate ofdegradation. DMA results showed that a great deal of internal stress that was built during orientation and hot-stretchingstages was released in the post-annealing stage for a1l PGA and PGA-co-PLA samples. During earlier stages of in vitrodegradation, both PGA and PGA-co-PLA samples exhibited the typical cleavage-induced crystallization mechanism. Theheat shrinkage in the glass transition area was found to disappear after 6-8 days of degradation for all PGA and PGA-co-PLAsamples, indicating the amorphous portions of the polymers lost orientation after a short period in the buffer solution, mostlikely due to relaxation of the cleaved chains.

Monte Carlo Si mulation of Damage Depth in Focused Ion Beam Milling Si_3N_4 Thin Film

The damage properties of Focused Ion Beam(FIB) milling Si3N4 thin film are investigated by the detailed analyzing images of nanoholes and simulation of Monte Carlo. The damage depth in the Si3N4 thin film for two different ion species(Gallium and Arsenic) under various parameters(ion energy, angle of incidence) are investigated by Monte Carlo method. The simulations show the damage depth increases with the increasing ion energy, the damage depth is dependent on the angle of incident ion, the curves of the damage depth for Ga ion and As ion at 30 keV nearly superpose, while the damage depth for Ga with 90 keV ion is more than that for As ion with the same energy.

LIBS光谱技术鉴别原料药或辅料中的金属元素

目的:建立简便、快速鉴别原料药或药用辅料中金属元素的激光诱导击穿光谱法(LIBS)。方法:以择几种含钠、钾、镁、钙、锌元素的原料药或药用辅料为模型,采用LIBS采集样品的原子光谱,基于原子光谱理论和NIST数据库,对166～800 nm波段范围内LIBS谱线进行辨识,鉴别样品中的金属元素。结果:获得的LIBS光谱中的特征谱线与样品中的金属元素一一对应。结论:LIBS光谱法是鉴别药物或药用辅料中金属元素的快速、准确、可靠的方法。

激光诱导击穿光谱技术及其在药学中的应用

激光诱导击穿光谱技术(LIBS)基于原子发射光谱和激光等离子体发射光谱,是一种正在发展中的对样品中元素成分进行快速、现场定性定量检测的分析技术。本文介绍了LIBS的由来、基本原理、实验装置和实验方法特点,并结合典型示例,综述了LIBS在药学方面的应用。分析得出LIBS技术应用方便快捷,能快速辨识药品真伪且应用前景广泛,有利于药品市场的质量监管,在药物分析中将获得更为广泛的应用。