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排序方式: 共有458条查询结果,搜索用时 31 毫秒
1.
采用PCR技术对2种亚洲龙鱼的mtDNAD_Loop全序列进行扩增和测序,序列结构分析和序列同源性比对结果表明,2种亚洲龙鱼的mtDNAD_Loop在靠近5’端有3个终止相关序列TAS(Ⅰ、Ⅱ、Ⅲ),靠近D_Loop的3’端有4个保守区域CSB1、CSB2、CSB3、CSB-D。在终止相关序列和保守区域之间是连续重复区域。经DNASP4.0软件分析,全序列中检测出多态位点数(S)为26,其中有17个转换,核苷酸多样性(Pi)为0.013,平均核苷酸差异数(K)为17.333。 相似文献
2.
为了给公路设计部门提供选线依据,运用瞬变电磁法在山西境内的某两条高速公路隧道工程设计线路段上进行探测,以查明下覆不良地质构造的发育情况.通过对瞬变电磁法的探测能力进行理论上的讨论,对不同地电断面情况下的异常体电磁响应的定性分析,得出用瞬变电磁法探测不良地质体的可行性结论.经过资料处理,查出不良地质构造赋存的位置,解释结果与钻探资料完全吻合. 相似文献
3.
探讨了windows编程环境下,编绘软件的网络实现方法。通过对WinSock编程方法的讨论,表明了编绘软件电子图板实现网络化编辑的可行性。 相似文献
4.
5.
CBERS-02B星HR与多光谱影像融合及评价 总被引:4,自引:0,他引:4
CBERS-02B星搭载了高分辨率全色相机HR和多光谱传感器CCD,HR影像可以与CCD影像融合,优势互补形成新的影像,既保持HR的高空间分辨率又保持CCD的光谱分辨率,HR影像同样可以与其它传感器影像融合形成新的影像。本文使用6种不同的融合方法融合HR与多光谱CCD以及SPOT5多光谱影像,并对融合结果进行了定性和定量评价,得到了HR与SPOT5多光谱影像融合较好的方法,表明了HR与其它传感器影像融合的潜力,同时也对HR和SPOT5多光谱融合影像及与CCD融合影像进行了初步的对比分析。 相似文献
6.
通过一个成功的钻孔后压浆桩工程实例,介绍了钻孔后压浆桩的优点、承载力计算方法和施工措施.桩基的静动载检测结果表明,施工中通过合理布置压浆管、控制压浆顺序和压浆量可使软弱土层得到较好的处理效果.本工程的成功经验可为类似工程提供有价值的参考. 相似文献
7.
Che Yong-tai Yu Jin-zi Zhang Shu-liang Fan Xue-fang Guo Jun-jie Zhang Tian-yuan Yang Jin-lan 《地震学报(英文版)》2002,15(2):226-233
A lot of slow fluctuations of water level have been observed in the original recording maps of subsurface fluid in Well Shuozhou,
Shanxi Province. Some typical recording maps of the “precursors” are introduced in the paper and the features of the “precursors”
recorded by the well are analyzed. The results show that 38% strong earthquakes possess this kind of record, which has a fluctuation
period arranging from several to tens of minutes and appear mostly two days before the earthquakes. Moreover, the mechanism,
transmission and responding conditions of well water level are discussed, as well as the scientific meaning and practical
value of the “precursor” of the well water level in earthquake predictions.
Foundation item: State Natural Science Foundation of China (19973011). 相似文献
8.
大口黑鲈抗菌肽hepcidin cDNA序列和结构分析 总被引:2,自引:0,他引:2
以大口黑鲈为材料,提取肝脏总RNA,经RT-PCR扩增出hepcidin cDNA的开放阅读框(ORF)及3′端非编码区序列,应用5′RACE方法得到大口黑鲈hepcidin cDNA5′末端。将所获得的两个片段分别克隆到T载体后进行测序,并拼接成大口黑鲈hepcidin全长cDNA。序列分析表明:大口黑鲈hepcidin全长cDNA为564bp,含有一个258bp的ORF,编码86个氨基酸残基,由信号肽(24个残基)、前肽(42个残基)和成熟肽(20个残基)3部分组成hepcidin前体。在前肽部分具有前肽转化酶典型的RX(K/R)R基元,成熟肽部分含有8个保守的半胱氨酸残基,可形成四个链内二硫桥,使β-折叠结构保持稳定。大口黑鲈Hepcidin与其他鱼类的同源性在29.7%~90.5%间,尤其是信号肽区域,与鳜、尼罗罗非鱼、真鲷、花鲈、黑鯛、金眼狼鲈仅有2~3个氨基酸的差别。 相似文献
9.
Impacts of native vegetation on the hydraulic properties of the concentrated flows in bank gullies 总被引:1,自引:0,他引:1
SU Zheng-an HE Zhou-yao ZHOU Tao WANG Jun-jie WANG Xiao-yi WANG Li-juan FANG Hai-dong SHI Liang-tao LIU Yi-han WU Zuo 《山地科学学报》2021,(4):907-922
To quantify the impacts of native vegetation on the spatial and temporal variations in hydraulic properties of bank gully concentrated flows, a series of in situ flume experiments in the bank gully were performed at the Yuanmou Gully Erosion and Collapse Experimental Station in the dry-hot valley region of the Jinsha River, Southwest China. This experiment involved upstream catchment areas withone-and two-year native grass(Heteropogon contortus) and bare land drained to bare gully headcuts, i.e., Gullies 1, 2 and 3. In Gully 4, Heteropogon contortus and Agave sisalana were planted in the upstream catchment area and gully bed, respectively. Among these experiments, the sediment concentration in runoff in Gully 3 was the highest and that in Gully 2 was the lowest, clearly indicating that the sediment concentration in runoff obviously decreased and the deposition of sediment obviously increased as the vegetation cover increased. The concentrated flows were turbulent in response to the flow discharge. The concentrated flows in the gully zones with native grass and bare land were sub-and supercritical, respectively. The flow rate and shear stress in Gully 3 upstream catchment area were highest among the four upstream catchment areas, while the flow rate and shear stress in the gully bed of Gully 4 were lowest among the four gully beds, indicating that native grass notably decreased the bank gully flow rate and shear stress. The Darcy–Weisbach friction factor(resistance f) and flow energy consumption in the gully bed of Gully 4 were notably higher than those in the other three gully beds, clearly indicating that native grass increased the bank gully surface resistance and flow energy consumption. The Reynolds number(Re), flow rate, shear stress, resistance f, and flow energy consumption in the gully beds and upstream areas increased over time, while the sediment concentration in runoff and Froude number(Fr) decreased. Overall, increasing vegetation cover in upstream catchment areas and downstream gully beds of the bank gully is essential for gully erosion mitigation. 相似文献
10.
建立了一种适用于海洋远程快速检测氰化物的检测方法,设计了一体化检测装置,未来可搭载到无人艇上实现自动快速检测。针对最佳检测条件进行了一系列优化,得到最佳检测条件:对于100 mL的待测样品,加入酒石酸固体1.5 g;用1~2滴浓度为150 g/L的碳酸钠溶液浸润苦味酸试纸;加热温度80℃,加热时间10min。在最佳检测条件下,检测检出限达0.3mg/L。该方法实现了适用于海水氰化钠的远程检测,大大提高了检测效率,无需人员进入污染现场,安全性高。可广泛用于海洋危化品泄漏、湖泊污染、现场应急筛选等场合的水体样品快速检测。 相似文献