抗旱保水剂膨润土-聚丙烯酸盐吸水树脂研究   总被引：2，自引：0，他引：2  

刘建朝  左可胜  李绍卿  李剑敏 《地球科学与环境学报》2005,27(4):58-62

利用丙烯酸盐在蒙脱石层间进行原位聚合，研究开发一种适用于农林业的抗旱保水剂。实验结果表明：聚合产物的综合性能较为理想，吸水树脂的保水作用主要体现在能够吸收大量的水，并且在压力下不脱水。  相似文献   

CygX—1硬态高能光子的时延   总被引：1，自引：1，他引：0  

屈进禄  李惕碚 《天文学报》2001,42(2):140-147

硬X射线和软射线光子的时延时研究主能辐射的一个重要方面，傅里叶交叉谱常常被用于教育处硬软光子之间的时延，但是交叉说示能在高于30Hz的傅里叶频率上从CygX-1测量到有统计意义的快速光变，由李惕培在时域上发展的交叉相关函方法能有效测量不同时间尺度上的时延，利用此交叉相关分析方法，讨论了不同观测时期CygX-1硬态高能光子时延 的性质，分析结果表明，CygX-1硬态在短的尺度（＜0．1秒）上存存在有意义的时间延迟，并将短时间尺度上的观测结果和各种CygX-1硬态模型进行了比较讨论。  相似文献   

Magnetic susceptibility variations of the Edicaran cap carbonates in the Yangtze platform and their implications for paleoclimate     

吴怀春  张世红  蒋干清  李海燕 《中国海洋湖沼学报》2005,(3)

1 INTRODUCTION One of the most intriguing phenomena in the late Neoproterozoic (~750 to 543 Ma) is the globa occurrence of thin carbonates that directly overlie glacial deposits in almost every continent (Kennedy 1996; Hoffman et al., 1998; Hoffman and Schrag 2002; Brasier and Shields, 2000; James et al., 2001 Jiang et al., 2003; Nogueira et al., 2003). These “cap carbonates”, commonly several to tens of meters thick, have attracted enormous interests because o their unusually negati…  相似文献   

基于GPS实现测频等功能的虚拟仪器的研制     

李涛  李忠华  朱才连 《时间频率学报》2005,28(1):15-21

设计和研制了一种适用于大专院校示范教学实验的虚拟仪器。该虚拟仪器以GPS接收模块输出的1PPS(秒脉冲)信号为基准,测量无源石英晶体振荡器频率,同时利用GPS信号实现了仪器的时间同步与测距功能。从硬件和软件两方面描述了该虚拟仪器的构成及设计方法,主要介绍和讨论基于GPS和虚拟仪器技术实现多功能测量的途径。  相似文献   

单片机在卫星天线控制系统中的应用     

樊昌元  邓洪 《成都信息工程学院学报》2005,20(1):41-44

主要介绍卫星天线控制系统中天线旋转定位控制的软硬件设计和实现。该部分的主要功能是：接收红外遥控器的信号；检测前面板上的按键信号；检测传感器反馈的信号；根据所得信号作出相应的动作。  相似文献   

Age-metallicity relation for F-stars     

Hong Bae Ann  Yong Hee Kang 《Astrophysics and Space Science》1986,118(1-2):325-327

We derived the age-metallicity relation for the solar neighbourhood from theuvby, H photometry of F-stars using the evolutionary models of Hejlesen (1980). It is shown that disk formation is divided into two phases according to the fast and slow collapse which accompany the initial rapid enrichment and slow increase of the metallicity of the galactic disk, respectively.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.  相似文献   

Timing of the Nihewan formation and faunas   总被引：2，自引：0，他引：2  

Chenglong Deng  Rixiang Zhu  Rui Zhang  Hong Ao  Yongxin Pan 《Quaternary Research》2008,69(1):77-90

Magnetostratigraphic dating of the fluvio-lacustrine sequence in the Nihewan Basin, North China, has permitted the precise timing of the basin infilling and associated Nihewan mammalian faunas. The combined evidence of new paleomagnetic findings from the Hongya and Huabaogou sections of the eastern Nihewan Basin and previously published magnetochronological data suggests that the Nihewan Formation records the tectono-sedimentary processes of the Plio-Pleistocene Nihewan Basin and that the Nihewan faunas can be placed between the Matuyama-Brunhes geomagnetic reversal and the onset of the Olduvai subchron (0.78-1.95 Ma). The onset and termination of the basin deposition occurred just prior to the Gauss-Matuyama geomagnetic reversal and during the period from the last interglaciation to the late last glaciation, respectively, suggesting that the Nihewan Formation is of Late Pliocene to late Pleistocene age. The Nihewan faunas, comprising a series of mammalian faunas (such as Maliang, Donggutuo, Xiaochangliang, Banshan, Majuangou, Huabaogou, Xiashagou, Danangou and Dongyaozitou), are suggested to span a time range of about 0.8-2.0 Ma. The combination of our new and previously published magnetostratigraphy has significantly refined the chronology of the terrestrial Nihewan Formation and faunas.  相似文献   

The bituminous mixtures of Tall-e Abu Chizan: A Vth millennium BC settlement in southwestern Iran     

Jacques Connan  John Zumberge  Kendra Imbus  Abbas Moghaddam 《Organic Geochemistry》2008,39(12):1772

Various bituminous artifacts were excavated from the Tall-e Abu Chizan, a late prehistoric (Middle Susiana to Middle Uruk) settlement on the middle of the Curvy plain, between the Karun River and the Ram Hormoz Plain. All samples dated from the Vth millennium BC and cover three periods: 5000–4700 BC (Late Middle Susiana), 4700–4200 BC (Late Susiana 1) and 4200–3900 BC (Late Susiana 2). The bitumens were studied using the techniques of petroleum geochemistry and were compared both to the unaltered crude oils produced from the main oil fields in the area and to the famous Mamatain oil seeps. All samples are very rich in bitumen (average 46 wt%) which has been biodegraded and oxidized. Despite these alteration phenomena, δ¹³C of asphaltenes occur within a narrow range of less than 1‰ PDB. Biodegradation affected the steranes, terpanes, dibenzothiophenes and mono- and triaromatic steroids. Molecular characteristics of terpanes, especially the occurrence of 18α (H)-oleanane, suggest that the bitumen from Tall-e Abu Chizan is a mixture generated from Cretaceous Kazdhumi and Eocene Pabdeh petroleum source rocks. In that respect, bitumens from Tall-e Abu Chizan belong to the same oil family as oil from the Naft Safid field, which is in the vicinity of the archaeological site. In fact, the bitumen at Tall-e Abu Chizan likely originated from oil seepages at Naft Safid. These oil seeps have not yet been sampled or analysed.  相似文献   

新疆塔中南坡奥陶系的地层缺失和沉积相变化   总被引：4，自引：0，他引：4  

蔡习尧  李越 《地层学杂志》2008,32(4)

按照奥陶系内部6个组沉积的时间片段拟定塔中南坡不同区块存在不同程度的缺失。部分关键层段的牙形石和几丁虫组合特征证明一间房组和恰尔巴克组在塔中部分井区是存在的,但恰尔巴克组的分布范围最狭窄。总体上,塔中南坡隆起区地层缺失较多,古城墟隆起基本完整。据缺失状况和岩相展布,显示塔中南坡的沉积单元具有由东往西迁移的特征,且各时段迁移的距离与速度存在较大差异。  相似文献   

车镇凹陷上古生界高分辨率层序地层研究   总被引：2，自引：0，他引：2  

吕大炜  李增学  李文涛  柳汉丰  刘海燕  吴立荣 《地层学杂志》2008,32(2):182-187

以高分辨率层序地层学原理为指导,利用测井、岩芯和录井等资料,对车镇凹陷上古生界不同级次基准面旋回进行了高分辨率层序划分。将上古生界划分为2个超长期、7个长期、16个中期和45个短期基准面旋回,精细对比研究了短期、中期和长期基准面旋回。其中,短期基准面旋回可分为2大类3种亚类,并区别出A型、B型不对称短期基准面旋回和C型对称性短期基准面旋回,总结了它们的结构特征、形成条件、岩性岩相组成;通过研究不同沉积体系下中期、长期基准面旋回特点,得出中期、长期基准面旋回的特点和发育特征,区别出不同沉积环境下层序界面特点;分析了研究区内超长期基准面旋回特征,综合分析认为车镇凹陷超长期基准面旋回以下降半旋回为主。  相似文献