SDH环网由二纤环扩容升级至四纤环的方案探讨

对双二纤 MS- SPring和四纤 MS- SPring的经济性、组网灵活性、业务可靠性等方面进行了比较 。

基于四纤自愈环继电保护通道的试验研究

山西电力主干通信网2.5 G系统四纤自愈环完成改造后,为验证基于四纤自愈环的通道参数是否满足继电保护技术要求,制定了在运行四纤环上开通继电保护通道并与继电保护装置进行互联试验的方案。通过试验,模拟了继电保护通道在收发时延不一致的情况及四纤环纤芯中断情况下继电保护通道时延变化情况,试验结果表明基于四纤自愈环的继电通道在切换过程中不存在收发时延不一致的情况,满足继电保护通道技术要求。

基于四纤自愈环改造的同步数字体系运行方式

随着山西电网结构的变化,同步数字体系通信网络不断完善,为了提高网络的可靠性,山西电力公司对省内SDH网络进行四纤自愈环改造,通过讨论省内网络结构变化,以及针对这些变化所进行的环网的同步方式的调整,提出网络变化时所应考虑的同步因素,提高网络的运行可靠性。

Synthesis and Neuroprotective Activity of Novel C4, C7 Derivatives in Tetracycline Series

Since the discovery of the tetracycline in 1953, numerous natural andsemisynthelic tetracyclines have been reported with broad spectrum antibacterial activity .Doxycycline 1 and minocycline 2 are semisyn-thetic second-generation tetracyclines that exertanti-inflammatory effects. These effects appear completely separate and distinct fromtheirantimicrobial actio. Minocycline and doxycycline are absorbed rapidly and show higher brainpenetrability than other tetracyclines. During recent years, doxycycline and minocycline have shownto have neuroprotective effects in models of global and focal ischemia . The neuroprotective effectsare assumed to result from the inhibition of microglia activation. Furthermore, from an in vitrostudy, it was reported that minocycline induces neuroprotection against NMDA-induced neurotoxicityby inhibiting p38 MAP ki-nase activity in microglia . However, neuroprotective mechanisms andstructure-activity relationships of these compounds in neurons are unclear.