排序方式: 共有74条查询结果,搜索用时 11 毫秒
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目的:研究高河菜提取物对小鼠消化道动力的影响.方法:采用炭末推进实验观察高河菜提取物对阿托品所致小鼠小肠推进抑制的影响;采用甲基橙胃残留率的方法观察高河菜提取物对阿托品所致小鼠胃排空抑制的影响.结果:高河菜提取物2g/kg能明显拮抗阿托品对小鼠小肠推进抑制的作用;高河菜提取物2g/kg、1g/kg和0.5g/kg均能拮抗阿托品对小鼠胃排空抑制的作用.结论:高河菜提取物对阿托品所致小鼠胃肠功能障碍有明显的改善作用. 相似文献
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Klaus Regenauer-Lieb Andrew Bunger Hui Tong Chua Arcady Dyskin Florian Fusseis Oliver Gaede Rob Jeffrey Ali Karrech Thomas Kohl Jie Liu Vladimir Lyakhovsky Elena Pasternak Robert Podgorney Thomas Poulet Sheik Rahman Christoph Schrank Mike Trefry Manolis Veveakis Bisheng Wu David A. Yuen Florian Wellmann Xi Zhang 《地球科学学刊》2015,(1)
Deep geothermal from the hot crystalline basement has remained an unsolved frontier for the geothermal industry for the past 30 years. This poses the challenge for developing a new un-conventional geom... 相似文献
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萨日娜 《吉林大学学报(理学版)》2017,55(6):1518-1522
通过对蚁群算法和粒子群算法分别进行改进,利用两种算法自身优势相结合的方式建立一种蚁群粒子群算法,以提高云计算资源调度效率,解决云计算中资源调度方案优化问题.实验结果表明,该算法所消耗的时间更少,效果更好. 相似文献
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在Hilbert空间中引入并研究一类非线性投影方程,利用不动点定理,我们得到了关于这类非线性投影方程解的一些新的存在性定理,所得的结果统一和发展了一些作者的近期工作。 相似文献
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【目的】林火是森林生态系统中重要的干扰因子,严重影响着森林的结构与功能。内蒙古大兴安岭是我国重要的森林生态系统之一,从内蒙古地区地域、海拔、火灾原因分布等可能导致火灾的时空因素分析林火灾害,为森林防火和管理提供有力的科学依据。【方法】基于遥感影像,借助ArcGIS 10.2和Origin等软件,分析了1980—2015年内蒙古地区森林火灾特点,结合时间、空间的因素,探讨林火的时空动态规律。【结果】内蒙古地区森林火灾时空上表现出规律性分布。受害森林面积年变化存在周期性规律,周期间隔16 a,且春季为林火高发季节,在进行森林防火的资源调节过程中,火灾发生次数较多的4、5月正处于春分、清明和谷雨时节,应以控制火源为主要内容。此外,月初林火发生概率相对较高,应在该时段提高警惕; 林火的发生主要集中在9:00—17:00; 多发于呼伦贝尔市、赤峰市、鄂尔多斯市和兴安盟等地区,其中兴安盟过火面积最大,大兴安岭林区火灾也比较频繁。【结论】内蒙古森林火灾频发,过火面积较大,且火灾频发与人类活动及气候特点息息相关。森林火灾主要由人为活动造成,必须严格控制野外火源、生活用火等。建议在掌握内蒙古自治区森林火灾时空动态特征的基础上,加强防火宣传与教育,并运用科学的森林防火措施,制定合理的森林防护政策。 相似文献
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乙烯信号转导与合成基因在延长花期中的应用 总被引:1,自引:0,他引:1
乙烯对花卉衰老具有强烈的促进作用,是造成花卉衰老的根本原因.本文主要综述了近几年来采用基因工程手段将乙烯信号转导途径和生物合成途径的相关基因转化到植物体内,从而延长花期方面的研究. 相似文献
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抓住竞赛契机 深化计算机专业教学改革 总被引:1,自引:0,他引:1
各种计算机类竞赛对高校计算机专业的教学改革起到了积极的促进作用,本文倡导抓住竞赛契机,引导和深化计算机专业教育教学改革,并对教学模式的改革、新课程体系的制定和强化教师队伍的建设提出了具体举措. 相似文献
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Images of geomorphological features that seem to have been produced by the action of liquid water have been considered evidence for wet surface conditions on early Mars. Moreover, the recent identification of large deposits of phyllosilicates, associated with the ancient Noachian terrains suggests long-timescale weathering of the primary basaltic crust by liquid water. It has been proposed that a greenhouse effect resulting from a carbon-dioxide-rich atmosphere sustained the temperate climate required to maintain liquid water on the martian surface during the Noachian. The apparent absence of carbonates and the low escape rates of carbon dioxide, however, are indicative of an early martian atmosphere with low levels of carbon dioxide. Here we investigate the geochemical conditions prevailing on the surface of Mars during the Noachian period using calculations of the aqueous equilibria of phyllosilicates. Our results show that Fe3+-rich phyllosilicates probably precipitated under weakly acidic to alkaline pH, an environment different from that of the following period, which was dominated by strongly acid weathering that led to the sulphate deposits identified on Mars. Thermodynamic calculations demonstrate that the oxidation state of the martian surface was already high, supporting early escape of hydrogen. Finally, equilibrium with carbonates implies that phyllosilicate precipitation occurs preferentially at a very low partial pressure of carbon dioxide. We suggest that the possible absence of Noachian carbonates more probably resulted from low levels of atmospheric carbon dioxide, rather than primary acidic conditions. Other greenhouse gases may therefore have played a part in sustaining a warm and wet climate on the early Mars. 相似文献