The mineralogical data materialized in the present work suggest that the previously described skarns at Ad Darb in the literature are actually marble deposits intercalated with schists and phyllites of different compo...The mineralogical data materialized in the present work suggest that the previously described skarns at Ad Darb in the literature are actually marble deposits intercalated with schists and phyllites of different compositions. The marble and associated metasediments lie to the west of striking ridges of marbles that are nearly aligned in the NNW-SSE direction. Garnet at Al Madhiq occurrence often occurs in the form of bands conformable with rock foliation (gneissosity and schistosity). It is suggested that the paragenesis “quartz-gar- net-epidote” is developed due to the percolation of some Al-rich solutions along rock foliation of the horn- blende gneiss, i.e. metasomatic garnet. Careful field investigation collaborated with petrographic and SEM studies, suggest the occurrence of another garnetiferous paragenesis associating quartz, mica and feldspar in pegmatites, aplites and quartz veins, i.e. exclusively igneous garnet. Metasomatic garnet in the calc-silicates of Al Madhiq is of grossular composition. It is commonly unzoned but some distinctly to slightly zoned crystals are observed where the core is andradite-rich and the rim is grossular. Metasomatic events responseble for growth of garnet in the calc-silicates led also to formation of epidote post-dating grossular. Hand specimens, microscopic investigation and BSE images prove that this epidote post-dates and replaces gros sular, and even rims it in some instances. Igneous garnet at Al Madhiq (almandine-spessartine) is found only in pegmatites and aplites that are genetically related to alkali granitoids. Sulphides (dominated by pyrite) occur in intemate association with domains rich in grossular and hence these sulphides are more likely hydrothermal indicating reducing conditions for formation of grossular.展开更多
目的探讨最佳自适应统计迭代重建(ASIR)百分比联合最优单能量技术提高腹部图像质量,优化腹部血管显示。方法搜集临床腹部能谱CT检查的32例腹部疾病患者资料,应用能谱分析软件,采用70 ke V、55ke V分别联合0%、30%、50%、70%ASIR模式进...目的探讨最佳自适应统计迭代重建(ASIR)百分比联合最优单能量技术提高腹部图像质量,优化腹部血管显示。方法搜集临床腹部能谱CT检查的32例腹部疾病患者资料,应用能谱分析软件,采用70 ke V、55ke V分别联合0%、30%、50%、70%ASIR模式进行腹部动脉期及门静脉期重建,比较70 ke V联合不同ASIR百分比模式下动脉期及门静脉期肝实质噪声(LN)、胰腺噪声(PN),竖脊肌噪声(SMN)以及肝CNR(LCNR)、胰腺CNR(PCNR)、门静脉CNR(PV-CNR)及主观图像质量评分之间差异有无统计学意义。同时比较55 ke V联合不同ASIR百分比模式下动脉期及门静脉期腹部动脉血管、门静脉CNR等相关指标及主观图像质量评分,并采用单因素方差分析进行比较。结果 70 ke V组不同ASIR比例中,LN、PN,SMN、LCNR及PCNR差异均有统计学意义(P<0.05)。主观图像质量评分显示动脉期及静脉期不同ASIR组间比较,30%组伪影最低;诊断信心度方面30%最高;噪声方面70%最低,微小结构及病变显示方面各ASIR组间无统计学差异。55 ke V组间,除了动脉期LCNR各组间差异无统计学意义,腹部各动脉血管CNR及PV-CNR,LN,SMN,PN,主观评分及门静脉期LCNR在不同ASIR组间差异均有统计学意义(P<0.05);主观评分方面以50%ASIR组最优(P<0.05)。结论 70 ke V+30%ASIR及55ke V+50%ASIR分别成为优化腹部图像质量及血管成像的最优化组合。展开更多
文摘The mineralogical data materialized in the present work suggest that the previously described skarns at Ad Darb in the literature are actually marble deposits intercalated with schists and phyllites of different compositions. The marble and associated metasediments lie to the west of striking ridges of marbles that are nearly aligned in the NNW-SSE direction. Garnet at Al Madhiq occurrence often occurs in the form of bands conformable with rock foliation (gneissosity and schistosity). It is suggested that the paragenesis “quartz-gar- net-epidote” is developed due to the percolation of some Al-rich solutions along rock foliation of the horn- blende gneiss, i.e. metasomatic garnet. Careful field investigation collaborated with petrographic and SEM studies, suggest the occurrence of another garnetiferous paragenesis associating quartz, mica and feldspar in pegmatites, aplites and quartz veins, i.e. exclusively igneous garnet. Metasomatic garnet in the calc-silicates of Al Madhiq is of grossular composition. It is commonly unzoned but some distinctly to slightly zoned crystals are observed where the core is andradite-rich and the rim is grossular. Metasomatic events responseble for growth of garnet in the calc-silicates led also to formation of epidote post-dating grossular. Hand specimens, microscopic investigation and BSE images prove that this epidote post-dates and replaces gros sular, and even rims it in some instances. Igneous garnet at Al Madhiq (almandine-spessartine) is found only in pegmatites and aplites that are genetically related to alkali granitoids. Sulphides (dominated by pyrite) occur in intemate association with domains rich in grossular and hence these sulphides are more likely hydrothermal indicating reducing conditions for formation of grossular.
文摘目的探讨最佳自适应统计迭代重建(ASIR)百分比联合最优单能量技术提高腹部图像质量,优化腹部血管显示。方法搜集临床腹部能谱CT检查的32例腹部疾病患者资料,应用能谱分析软件,采用70 ke V、55ke V分别联合0%、30%、50%、70%ASIR模式进行腹部动脉期及门静脉期重建,比较70 ke V联合不同ASIR百分比模式下动脉期及门静脉期肝实质噪声(LN)、胰腺噪声(PN),竖脊肌噪声(SMN)以及肝CNR(LCNR)、胰腺CNR(PCNR)、门静脉CNR(PV-CNR)及主观图像质量评分之间差异有无统计学意义。同时比较55 ke V联合不同ASIR百分比模式下动脉期及门静脉期腹部动脉血管、门静脉CNR等相关指标及主观图像质量评分,并采用单因素方差分析进行比较。结果 70 ke V组不同ASIR比例中,LN、PN,SMN、LCNR及PCNR差异均有统计学意义(P<0.05)。主观图像质量评分显示动脉期及静脉期不同ASIR组间比较,30%组伪影最低;诊断信心度方面30%最高;噪声方面70%最低,微小结构及病变显示方面各ASIR组间无统计学差异。55 ke V组间,除了动脉期LCNR各组间差异无统计学意义,腹部各动脉血管CNR及PV-CNR,LN,SMN,PN,主观评分及门静脉期LCNR在不同ASIR组间差异均有统计学意义(P<0.05);主观评分方面以50%ASIR组最优(P<0.05)。结论 70 ke V+30%ASIR及55ke V+50%ASIR分别成为优化腹部图像质量及血管成像的最优化组合。
