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711.
陈娜  朱磊  从常奎 《陕西地质》2007,25(2):66-71
在厚松散层中进行钻孔施工较常规钻孔存在一些技术难题,按照常规方法达不到钻孔目的或者花费较大的人力和物力。本文通过分析松散层钻孔正常钻进的影响因素,采用正循环钻孔施工技术进行施工,提出钻孔防偏和纠偏措施,最后给出了厚松散层钻孔施工技术措施,对厚松散层钻探技术具有一定的指导意义。  相似文献   
712.
符学兵 《江苏地质》2007,31(4):370-372
从水泥土的固化机理出发,结合水泥搅拌桩桩身标准贯入试验和水泥土配合比试验,分析讨论了土性指标、土质条件和地层性质对水泥搅拌桩成桩质量的影响。  相似文献   
713.
The absorption and accumulation of Pb, Zn, Cu and Cd in some endurant weed plant species that survived in an old smeltery in Liaoning, China, were systematically investigated. Potential hyperaccumulative characteristics of these species were also discussed. The results showed that metal accumulation in plants differed with species, tissues and metals. Endurant weed plants growing in this contaminated site exhibited high metal adaptability. Both the metal exclusion and detoxification tolerance strategies were involved in the species studied. Seven species for Pb and four species for Cd were satisfied for the concentration time level standard for hyperaccumulator. Considering translocation factor (TF) values, one species for Pb, seven species for Zn, two species for Cu and five species for Cd possessed the characteristic of hyperaccumulator. Particularly, Abutilon theophrasti Medic, exhibited strong accumulative ability to four heavy metals. Although enrichment coefficients of all samples were lesser than 1 and the absolute concentrations didn’t reach the standard, species mentioned above were primarily believed to be potential hyperaccumulators.  相似文献   
714.
715.
土壤侵蚀治理范式与生态学理论的耦合关系   总被引:1,自引:0,他引:1  
目前土壤侵蚀已经成为全球普遍关注的环境问题, 土壤侵蚀治理范式是近年水土保持研 究中的一个热点。本文探讨了“范式”在科学研究中的变迁过程以及对土壤侵蚀防治的重要意义, 并且讨论了土壤侵蚀防治范式与生态学范式之间的耦合关系, 指出生态学思想对土壤侵蚀科学 的发展有重要的借鉴作用, 强调在进行土壤侵蚀研究过程中必须考虑生态因子。土壤侵蚀过程和 生态过程是相互渗透在一起, 它们之间所表现的是相辅相成的耦合关系, 生态学中的自然均衡思 想、系统非平衡态理论、等级缀块动态理论都深刻的影响着土壤侵蚀科学的发展并且都得到不同 程度的应用。在土壤侵蚀研究过程中必须重视生态环境平衡思想。  相似文献   
716.
晋玲  李鸣  张勇  白蕾  安黎哲  陈拓 《中国沙漠》2007,27(3):466-468
 摸索沙拐枣属(Calligonum L.)七种植物沙拐枣(Calligonum mongolicum Turcz. )、泡果沙拐枣(C. junceum (Fisch. et Mey.) Endl.)、无叶沙拐枣(C. aphyllum (Pall.) Gürke)、红果沙拐枣(C. rubicundum Bge.)、心形沙拐枣(C. cordatum E. Kor. ex N. Pavl.)、密刺沙拐枣(C. densum Borszcz.)、乔木状沙拐枣(C. arborescens Litv.)的总DNA提取方法并对DNA样品的纯度和浓度进行鉴定,对传统的CTAB法进行方法和材料的改进,开展与总DNA相关的PCR扩增和其他遗传学分析,并取得满意的结果。其结果对于沙拐枣属植物的有关研究提供了有效的实验手段。  相似文献   
717.
The December 26, 2003 Mw 6.6 Bam earthquake is one of the most disastrous earthquakes in Iran. QuickBird panchromatic and multispectral satellite imagery with 61 cm and 2.4 m ground resolution, respectively provide new insights into the surface rupturing process associated with this earthquake. The results indicate that this earthquake produced a 2–5 km-wide surface rupture zone with a complex geometric pattern. A 10-km-long surface rupture zone developed along the pre-existing Bam fault trace. Two additional surface rupture zones, each 2–5 km long, are oblique to the pre-existing Bam fault in angles of 20–35°. An analysis of geometric and geomorphic features also shows that movement on the Bam fault is mainly right-lateral motion with some compressional component. This interpretation is consistent with field investigations, analysis of aftershocks as well as teleseismic inversion. Therefore, we suggest that the 2003 Bam earthquake occurred on the Bam fault, and that the surface ruptures oblique to the Bam fault are caused by secondary faulting such as synthetic shears (Reidel shears). Our fault model for the Bam earthquake provides a new tectonic scenario for explaining complex surface deformations associated with the Bam earthquake.  相似文献   
718.
The No. 6 Coal-bed from the Heidaigou Mine, Jungar Coalfield, Inner Mongolia is a super-large Ga deposit. The dominant carrier of Ga is boehmite in coal. The study of coal facies may provide genetic enrichment information of Ga and its carrier (boehmite) in the Ga deposit. On the basis of study on coal petrology and mineralogy, it was found that the No. 6 Coal-bed from the Heidaigou Mine of Jungar was enriched in inertinites and the microlitho-types were dominated by clarodurite. The maceral morphological features and association indicate that the coal-bed was formed in a dry sedimentary environment or in a periodic dry sedimentary environment caused by the alternating variations of groundwater level. The optimum conditions for the enrichment of Ga and its particular carrier (boehmite) were dominated by four transitional conditions: (1) the upper delta plain which was the transitional zone between alluvial and lower delta plains, (2) the transitional zone between the dry and wet forest swamps, being slightly apt to the dry one, (3) the transitional tree density between the thick and loose ones, and (4) the low moor that was the transitional zone between two high moors during peat accumulation.  相似文献   
719.
The No. 6 Coal-bed from the Heidaigou Mine, Jungar Coalfield, Inner Mongolia is a super-large Ga deposit. The dominant carrier of Ga is boehmite in coal. The study of coal facies may provide genetic enrichment information of Ga and its carrier (boehmite) in the Ga deposit. On the basis of study on coal petrology and mineralogy, it was found that the No. 6 Coal-bed from the Heidaigou Mine of Jungar was enriched in inertinites and the microlitho-types were dominated by clarodurite. The maceral morphological features and association indicate that the coal-bed was formed in a dry sedimentary environment or in a periodic dry sedimentary environment caused by the alternating variations of groundwater level. The optimum conditions for the enrichment of Ga and its particular carrier (boehmite) were dominated by four transitional conditions (1) the upper delta plain which was the transitional zone between alluvial and lower delta plains, (2) the transitional zone between the dry and wet forest swamps, being slightly apt to the dry one, (3) the transitional tree density between the thick and loose ones, and (4) the low moor that was the transitional zone between two high moors during peat accumulation.  相似文献   
720.
MCAI课件的开发   总被引:1,自引:0,他引:1  
介绍了开发多媒体计算机辅助教学课件《台风》的设计思想及过程,其中包括系统分析、结构设计、关键技术和课件实现等,为相关人员开发MCAI(Multimedia Computer-Assisted Instruction)课件提供了借鉴。  相似文献   
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