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担载四核羰基簇——FeCo_3(CO)_11PPh_3^-在聚苯乙烯表面簇骼畸变的EXAFS研究
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作者 卢建军 寇元 +3 位作者 罗玉忠 李红兵 傅宏祥 殷元骐 《化学学报》 SCIE CAS CSCD 北大核心 1992年第7期661-667,共7页
通过配体取代将四核羰基簇FeCo_3(CO)_(12)^-锚联在膦化的聚苯乙烯表面,获得担载簇FeCo(?)(CO)_(11)PPh_3^-/poly,目的在于使簇骼结构偏离较高对称性.以考察锚联过程对簇结构的影响.本文以EXAFS(Extended X-ray Absorption Fine Structu... 通过配体取代将四核羰基簇FeCo_3(CO)_(12)^-锚联在膦化的聚苯乙烯表面,获得担载簇FeCo(?)(CO)_(11)PPh_3^-/poly,目的在于使簇骼结构偏离较高对称性.以考察锚联过程对簇结构的影响.本文以EXAFS(Extended X-ray Absorption Fine Structure)方法研究了担载样品的结构.结果显示担载簇与FeCo_3(CO)_(11)PPh_3^-晶体具有相同的结构模式,尤其是膦配体确实与一Co原子相连接.EXAFS结果表明:(1)与FoCo_3(CO)_(12)^-(其簇骼具有三重对称性结构)比较,锚联使Co—Fe键增长0.005nm;金属-金属及金属-桥联碳壳层的Debye-Waller因子均增大约一倍而金属-端联碳壳层的值变化很小.说明金属-金属间实际键长值具有一较宽分布,因而其簇骼已偏离了三重对称结构;(2)与FeCo_3(CO)_(11)PPh_3^-晶体的结构比较.Co—Fe键长长0.003nm.而Co—Co键长则短约0.002nm.考虑到EXAFS分析只能给出平均键长值,因此认为,存在于FeCo_3(CO)_(11)PPh_3^-晶体中的由于一个羰基被膦配体取代而引起的簇骼畸变,在锚联后被加剧. 展开更多
关键词 锚联 羰基簇 EXAFS 铁钴羰基簇
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关于膨胀型软弱地层中隧道修建及病害防治问题的探讨 被引量:1
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作者 彭刚 《四川建材》 2008年第5期45-47,共3页
针对某高速公路隧道塑性大变形软弱膨胀型复杂地质特点以及该隧道在穿越该地层时发生的大变形和衬砌破坏等现象,本文对该隧道开挖过程和对已出现病害区段进行治理采用的几项关键技术展开讨论,其中采用的预应力自钻式锚杆、中深孔注浆加... 针对某高速公路隧道塑性大变形软弱膨胀型复杂地质特点以及该隧道在穿越该地层时发生的大变形和衬砌破坏等现象,本文对该隧道开挖过程和对已出现病害区段进行治理采用的几项关键技术展开讨论,其中采用的预应力自钻式锚杆、中深孔注浆加固手段、卵型结构断面、纵向槽钢联锚、先仰拱后拱墙全断面衬砌等技术对抑制围岩的变形,保障隧道衬砌的安全起到了积极的作用。 展开更多
关键词 塑性大变形 软弱膨胀型地层 中深孔注浆加固 卵型结构断面 纵向槽钢 全断面衬砌 自钻式
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Deformation mechanism of high-stress and broken-expansion surrounding rock and supporting optimization based on the gray correlation theory 被引量:6
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作者 余伟健 WANG Ping DU Shao-hua 《Journal of Chongqing University》 CAS 2014年第3期99-114,共16页
Aiming at the large deformation and support problems of high-stress and broken-expansion surrounding rock, and taking 1 000 m level roadway of Mine II in Jinchuan as the research object, an investigation on the deform... Aiming at the large deformation and support problems of high-stress and broken-expansion surrounding rock, and taking 1 000 m level roadway of Mine II in Jinchuan as the research object, an investigation on the deformation and damage of roadway surrounding rock and an analysis of its mechanism were carried out. The gray correlation theory was used in support scheme optimization design. First, causes and mechanism of deformation of the 1 000 m horizontal transport channel were analyzed through field investigation, laboratory test and data processing methods. We arguued that poor engineering geological conditions and deep pressure increases were the main factors, and the deformation mechanism was mainly the ground deformation pressure. Second, the gray correlation theory was used to construct supporting optimization decision method in the deep roadway. This method more comprehensively considers various factors, including construction, costs, and supporting material functions. The combined support with pre-stressed anchor cables, shotcrete layer, bolt and metal net was put forward according to the actual roadway engineering characteristics. Finally, 4 support schemes were put forward for new roadways. The gray relational theory was applied to optimizing the supporting method, undertaking technical and economic comparison to obtain the correlation degree, and accordingly the schemes were evaluated. It was concluded as follows: the best was the flexible retaining scheme using the steel strand anchor; the second best was the one using plate anchors on the top and rigid common screw steel bolt on the two sides; the ttiird was; the rigid common screw steel bolt in full section of roadway; and the worst is the planished steel rigid support. The optimized scheme was applied to the 1000 m level of new excavation roadway. The results show that the roadway surrounding rock can reach a stable state after 5 to 6 months monitoring, with a convergence rate less than 1 mm/d. 展开更多
关键词 deep high stress broken-expansion surrounding rock deformation and failure of roadways gray correlation theory
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