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云南美登木内生真菌Phomopsis sp. Lz42的化学成分 总被引:2,自引:0,他引:2
从云南美登木内生真菌Phomopsis species Lz42的琼脂平板发酵物中分离得到2个倍半萜和5个麦角甾醇类化合物(1~7), 其中化合物1和2为新化合物. 应用波谱技术确定其结构为4-Deacetyl-10-oxo-dihydrobotrydial(1)和麦角甾-6,22-二烯-5α,8α-环二氧-3-甲酸酯(2). 相似文献
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Thermoelectric power measurements are reported for seven samples with different x in the Gd1.85-xSmxCe0.15CuO4 system at temperatures ranging from 80K to 300K. For Sm-rich superconducting samples, thermoelectric power S has a small negative value and is almost temperature independent. As the content of Sm decreases, the absolute value of S increases and a broad valley appears in the S(T) curve. The results which can be interpreted in terms of a two-channel model support the existence of mid-gap states with Fermi level close to the minimum of the density of states as well as the coexistence of electron and hole carriers. It is suggested that a linear temperature dependence of S with a small negative slope is close to the intrinsic behavior in the a-b plane of normal states for superconducting samples. 相似文献
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Thermoelectric power measurements are reported for seven samples with different x in the Gd1.85-xSmxCe0.15CuO4 system at temperatures ranging from 80K to 300K. For Sm-rich superconducting samples, thermoelectric power S has a small negative value and is almost temperature independent. As the content of Sm decreases, the absolute value of S increases and a broad valley appears in the S(T) curve. The results which can be interpreted in terms of a two-channel model support the existence of mid-gap states with Fermi level close to the minimum of the density of states as well as the coexistence of electron and hole carriers. It is suggested that a linear temperature dependence of S with a small negative slope is close to the intrinsic behavior in the a-b plane of normal states for superconducting samples. 相似文献
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观测了金锡相间周期结构薄膜的弱局域效应现象,与经典现象不同,观察到了有效的自旋轨道散射驰豫时间τ50随温度明显的变化,在传统的WL的基础上,用一个简单的模型进行了解释。 相似文献
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用磁控溅射和后期退火的方法,首次制成了完全取向的D相准晶薄膜。这种薄膜对准晶的基础研究和应用研究都有重要意义。 相似文献
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在氨水-NH4Cl介质(pH 9.0)和沸水浴加热下,铜离子对氨苄青霉素的降解反应具有催化作用,其降解产物可产生荧光。据此建立了测定氨苄青霉素的方法。氨苄青霉素的浓度在1.5×10-7~3.0×10-6mol·L-1范围内与荧光强度呈线性关系,检出限为4.0×10-8mol·L-1。可用于氨苄青霉素胶囊的分析及尿液中氨苄青霉素的测定,平均回收率为95.3%~101.4%。研究表明,反应的活化能为34.88 kJ·mol-1,100℃速率常数为4.68 h-1。 相似文献
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