共查询到14条相似文献,搜索用时 140 毫秒
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氨噻肟酸-锅法合成头孢吡肟盐酸盐 总被引:2,自引:0,他引:2
以氨噻肟酸为原料与二乙氧基硫代磷酰氯反应合成新活性酯溶液,直接与(6R,7R)-7-氨基-3-[(1-甲基-1-吡咯烷)甲基]头孢-3-烯-4-羧酸盐酸盐(7-Acp)在混合溶剂中反应得到头孢吡肟盐酸盐一水合物,该合成方法产率高、质量好、成本低,适合于生产。 相似文献
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本文用pH电位法研究了在温度为25±0.1℃,离子强度为0.1mol/L(NaNO3)的水溶液中,过渡金属离子(Co(Ⅱ)、Ni(Ⅱ)、Cu(Ⅱ)、Zn(Ⅱ)与头孢氨噻肟的配位作用,报导了溶液中头孢氨噻肟配体的酸解离常数和配合物形成的稳定常数.结果表明,溶液中金属离子与头孢氨噻肟配体主要以1∶1形式的配合物存在. 相似文献
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为了研究注射用头孢他美钠在大鼠体内的药代动力学及组织分布特点,将180只SD大鼠随机分为36组,分别静脉注射50、100、1 000 mg·kg~(-1)头孢他美钠,于不同时间点采血,分离血清;另将36只大鼠随机分成3组,分别静脉注射100 mg·kg~(-1)头孢他美钠,于不同时间点取各组织制成匀浆.采用HPLC法测定血清及各组织中头孢他美的浓度,用3p97软件计算药代动力学参数.头孢他美在SD大鼠血清中的药代动力学特征符合二室模型,低、中、高剂量下的主要药动学参数:Cmax为(66.70±21.59)、(216.90±43.22)和(1 972.70±125.54)μg·m L-1,t1/2β为(1.49±0.20)、(1.36±0.20)和(1.27±0.16)h,AUC(0~12)为(139.05±27.93)、(293.01±65.55)和(2 627.32±134.92)μg·h·m L~(-1);静脉注射头孢他美钠1 h时大鼠组织中头孢他美浓度最高,此时头孢他美在各组织中的浓度从高到低依次为肾、肝、肺、胃、心、骨骼肌、脾、小肠、脂肪、脑、卵巢和睾丸.结果表明,静脉注射头孢他美在大鼠血清和部分组织中浓度较高,无蓄积. 相似文献
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本文借助自变量代换,获得了三阶变系数线性微分方程的新的可积类型,并且得到了三阶变系数线性微分方程化为三阶常系数线性微分方程的充要条件. 相似文献
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本文综述了广谱抗蠕虫新药氟苯达唑的抗蠕虫活性、应用及其安全性,为我国动物蠕虫病的防治提供参考。 相似文献
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王定一 《华中科技大学学报(自然科学版)》1987,(3)
本文提出用动态规划法与等微增率法相结合、以开停机指标数确定运行机组台号的水电站自动发电控制(AGC)新算法,以满足在线实时运行的要求.文中介绍了该法的简易方案在新丰江水电站上应用情况. 相似文献
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《科学通报(英文版)》2006,51(Z1)
The stability of oases is one of the key scientific issues in the process of evolution and management of oases in arid areas. The stability of oases and its representation are also different at different scales. This paper deals with the stability of oases at the landscape patch scale with a case study in the Sangong River Watershed of Tianshan Mountains. We employed the remote sensing, geographic information system and mathematical statistical methods to process the remote sensing images of three periods in 1978, 1987 and 1998, and put forward the approaches for representing the oasis stability at the landscape patch scale. The landscape control capacity of oasis patches is a kind of natural driving forces of the dynamic landscape change. The control capacity of a certain patch type on landscape change increases with its area and shape complexity and contrasts between it and other patches, and reduces with its spatial distances between it and other patches. The patch type with the strongest control capacity should be the matrix of landscape. The conversion of oasis landscape patches results from both natural and anthropogenic driving forces, particularly the anthropogenic driving forces. The higher the conversion proportion is, the lower the stability of patch types is and the stronger the anthropogenic disturbance is. The patch type with the strongest net control capacity in the Sangong River Watershed in 1987 was the desert grassland, which was the matrix of landscapes; but the matrix of landscapes had been changed into the irrigated lands in 1987 and 1998. The control capacities of landscape patches on the oasis landscape evolution have gradually reduced with time in the Sangong River Watershed, and the change extents also have reduced gradually. This reveals that the interaction among the landscape patch types generally tends to reduce, and the natural stability of the oasis landscape patches generally tends to increase. However, the conversion among the landscape patches occurs more frequently due to the increase of intensive human activities, which probably causes the lower stability of environmental resources patch and higher stability of introduced patches in the oasis landscape. 相似文献
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本文将模式识别技术引入到启发式搜索当中,开展一种新的搜索——学习式搜索——的研究。我们给出了一个学习式的搜索算法SCDF,并证明了该算法的平均复杂度可达到线性。 相似文献
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The river corridor areas in the middle and lower reaches of the Tarim River are dominated by the traditional green corridors along the river section from the Qara Reservoir in Yuli County to the Taitema Lake in Ruoqiang County, which plays an important role in the social and economic development in the Tarim River Watershed with a extremely significant ecological functions. The buffer zones perpendicular to the watercourse were defined along both riversides at a 5-km interval beginning from the watercourse (10 km wider) using the method of the buffer zone analysis. The landscape pattern indexes of each buffer zone were calculated, and the indexes of the main landscape patterns were analyzed so as to reveal the radiative effect and the characteristics of the river corridors on landscape and patch levels. The results show that the radiative width is generally 30 km in the study area, and can be up to 50-70 km in sub- region FG1 because the study area is located in two drainage basins, with an ecological interstitial zone between them. The landscapes of woodlands and wetlands are generally distributed within the 10 km buffer zone (it means that the buffer zone is 5 km away from the watercourse; the same hereafter) along both riversides. Moreover, the closer the buffer zone is to the watercourse, the higher the patch density and the largest patch index are. In the ecological and environmental regeneration for the study area, the extent of ecological effect of the river corridors must be fully considered, and the projects must be scientifically and rationally planned and designed. 相似文献
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世界各地因其自然、历史、社会诸因素影响,国家与法律诞生模式不尽相同。中国考古学的发展从实物资料证明了中国文明诞生于夏代以前的龙山时代,而对历史文献中关于夏及夏代以前传说时期社会情的分析也佐证了这一观点。生产发展和思维发展是中国国家和法律产生发展的其本动力。 相似文献
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从科学与艺术的基本特点出发,在理论研究与科学教育实践的基础上,形成了把科学与艺术相关联,从而进行科学教育的思想.依据上述思想,提出了通过科学与艺术的关联,能够实现其独特的教育功能.即通过科学美与艺术美相交汇,对学生进行审美教育;通过科学研究风格与艺术创作风格相交流,使学生形成学习与探究风格;通过科学家发现个性与艺术家创作个性相交融,来培养学生的健全人格. 相似文献
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程波 《杭州师范学院学报(社会科学版)》2009,31(4)
通过对中国当代先锋电影和底层的关系作逻辑和历史的梳理,对"先锋的底层转向"以及"先锋底层转向之后"、中国当代新生代电影"底层泛化"的外部语境、表现及其内在原因和规律等问题作深入的探讨,力图通过建构"泛底层"这个概念,来表述中国当代先锋电影的"底层"悖论. 相似文献