地裂缝场地隧道暗挖地表沉降影响因素分析

以西安地铁6号线区间隧道穿越f8地裂缝为工程背景,对传统交叉中隔墙(cross diaphragm,CRD)工法隧道开挖施工穿越地裂缝场地全过程进行了三维有限元动态数值模拟,分析了开挖方向、隧道埋深、隧道洞径以及隧道穿越地裂缝的角度4个因素对暗挖隧道穿越地裂缝场地施工地表沉降的影响.结果表明:地表沉降曲线随开挖进尺均呈...     

小鼠电激怒实验中应用研制的智能化电刺激系统提高成模率的探索

摘要:目的 为提高小鼠电激怒模型制备成功率,研制了智能化电刺激系统以满足电激怒实验要求。 方法 电刺激系统由计算机窗口界面输入用户的控制参数,通过计算机系统与 STM32F103 单片机之间的 RS232 通讯,将用户输入的控制参数传入 STM32F103 单片机中,控制高压输出电路输出用户所需高压脉冲到鼠笼电极装置,以此激怒小鼠,并在动物实验中应用。 结果 制备小鼠激怒模型,通过采用计算机设定电刺激参数,使小鼠激怒模型制备的成功率达 90% ,并符合实验动物福利的“3R”原则要求,可以满足氯丙嗪对小鼠抗电激怒实验效果观察。 结论 研制的电刺激系统实现了计算机对刺激参数的智能化控制,技术性能可满足小鼠电激怒实验教学的要求。     

微波法合成含1,1’-联萘骨架的对称酰胺型开链冠醚

在微波辐射条件下高效合成了3种含1,1’-联萘骨架的对称酰胺型开链冠醚,产物结构经IR,1 H-NMR进行了表征.结果表明,该方法具有反应步骤短,时间短,产率高等优点,是合成含1,1’-联萘骨架的对称酰胺型开链冠醚的有效方法之一.     

A huge oceanic-type UHP metamorphic belt in southwestern Tianshan, China: Peak metamorphic age and P-T path

Recent progress in the study of the UHP metamorphic belt in southwestern Tianshan, China, is summarized in this paper. This about 80-kin-long and over 10-km-wide UHP belt has been recognized by the discovery of coesite, coesite pseudomorphs and other UHP minerals. It is the largest oceanic-type UHP metamorphic belt reported so far. It has formed due to northward subduc- tion of the Tianshan Paleo-Ocean. U-Pb dating of metamorphic rims of zircons from a coesite-bearing garnet-phengite schist yields a peak UHP metamorphic ages of 320±3.7 Ma. Combined with ages of 233-226 Ma obtained from rims of zircons from retrograded eclogites, a long retrograde metamorphic evolution （〉70 Ma） has been revealed. According to phase equilibria mod- eling, the P-T paths of both coesite-bearing eclogites and garnet-phengite schists are characterized by thermal relaxation, i.e., the metamorphic temperature peak lags behind the pressure peak, indicating that the UHP rocks experienced slow and long heating and decompression during exhumation in the subduction channel. On the basis of the field observation that a small amount of eclogite lenses is wrapped in large volumes of metapelites, and the similar P-T paths of both rock types, we propose that the ex- humation of the UHP eclogites from southwestern Tianshan, China, may have resulted from the exhumation of large volumes of low-density metapelites, which carried the denser eclogites to the Earth＇s surface.     

佳禾沟泥石流堆积物的粒度与强度关系分析

佳禾沟位于云南省维西县中路乡佳禾村,历史上曾多次发生不同规模的泥石流,并造成了人员伤亡和财产损失。通过对沟道流域沿线不同位置取样,用泥石流颗粒标度分析法并结合强度实验,发现佳禾沟泥石流松散堆积物的颗分参数μ与P(D_2)之间存在线性关系,这说明μ影响了泥石流的启动;物源区中的细颗粒的迁移、上游泥石流部分物质的随机性停歇和沟道支沟和主沟陡坡物质的随机性补给导致了颗分参数(μ,D_c)的波浪式发展。黏聚力c与μ之间的关系为线性关系,c随着μ的增加而增加。这说明细颗粒的组成控制了黏聚力c的大小,因此推断黏聚力受到细颗粒之间的胶结作用和静电作用等因素的影响。内摩擦角φ与Dc之间的关系为负线性相关,而φ随着D_c的增加而变小,粗颗粒决定了φ的发展。因此,在相同条件下,较大的μ和较小的D_c组合的土体,其强度较大;这从定量的角度上验证了颗粒级配与土体强度的关系。以上结论是否适用于其他流域需进一步验证。此外,还应结合颗粒形状,土动力学,渗透理论分析泥石流发生机理。