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61.
��������С�����պϻ��Զ������㷨�о� 总被引:1,自引:0,他引:1
??????С????????????????????????????????????????????????????????????????????????????·?????????????????????????????????С?????????????????????GPS???????????????????????????????÷??????????? 相似文献
62.
Deli YU Shufeng LIU Liyu TIAN Peiping ZHANG. College of Material Science Engineering Jilin University Changchun China 《东北亚地学研究》2008,11(3):188-190
Analyzing raw material's structure and performance of bentonite from Panzhihua in Sichuan, the authors think that it is adequate for agglomerant of iron smelting. According to its composition and property we have researched the purification and modification of I/S bentonite under conditions of different dispersants and sodium agent. XRD test result reveals that the essential minerals of Panzhihua bentonite are I/S mixed-layer ones, and FTIR analysis shows that when adding 1.5% sodium pyrophosphate to the bentonite slurry during purification, the composition of quartz in bentonite decreases to less than 4% and I/S is more than 90%. The optimized modification technic conditions are Na2CO3 (4%) and CMC-Na (3%) as modified agents, the clay and water are 10 vs. 1, and the temperature is 75℃. It is 40 min for stirring time and reacting time is 4 h. Under the conditions we can get the modified I/S bentonite with colloid index more than 500 nd/15 g. 相似文献
63.
中国丹霞地貌空间格局 总被引:1,自引:0,他引:1
1 IntroductionD anxia landform ,a kind of im portantscenic landform ,has its unique function in shape-m akingand scenery-constructing.It is distributed throughout m ost parts of China (H uang, 1999, 2003;Figure 1). It has m uch value in tourism for its re… 相似文献
64.
基于地震动参数的建筑物震害研究 总被引:15,自引:3,他引:12
本文介绍了多步简化的push—over(MSP)方法,引导出求解单体建筑物易损性指数和群体建筑物易损性指数的办法,并通过建筑物平均易损性指数曲线,来评价城市的总体抗震性能。本文不采用过去以烈度为地震输入的易损性评定方法,采用地震动参数作为城市建筑物易损性的评定标准。给出的易损性指数曲线,可用来查找不同地震动参数下各类建筑物的易损性结果,比较城市各类建筑物的抗震性能。本文研究可望在城市建筑物震害评估中有好的应用前景。 相似文献
65.
Nitrous oxide (N2O) is a potent greenhouse gas. Mitigating N2O emission is critical for combating global climate change and improving the ecological environment. Many studies have focused on factors affecting N2O emission from agricultural soils, but rarely on the relationship among these factors. In the present study, continuous measurement on N2O emission was conducted in a maize system in Griffith, Australia and the relationships between N2O emission, soil properties and weather conditions were examined. Principal component analysis and path analysis were used to analyze these data in correlation coefficient and the direct and indirect effects to N2O emission. Results indicated that (1) the major factors affecting N2O emission were WFPS, mineralized nitrogen (Mineral N), daily mean temperature (T mean) and CO2 concentration. The factors of direct influence N2O emission were following Mineral N, CO2, WFPS, and T mean. The indirect influence N2O emission was following T mean, WFPS, Mineral N, and CO2 concentration. (2) The standard multiple regression describing the relationship between N2O emission and its major factors were Y = ?37.162 + 0.5267 X 1 + 0.4331 X 2 + 0.3014 X 3 + 0.2392 X 4 (r = 0.924, p < 0.01, n = 151), where Y is N2O emission, X 1 is Mineral N, X 2 is CO2, X 3 is WFPS and X 4 is T mean. (3) N2O emission from agricultural soils can be monitored and mitigated through improved management practices such as irrigation, straw retention and fertilizer application. 相似文献
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Based on surfaced-related multiple elimination (SRME),this research has derived the methods on multiples elimination in the inverse data space.Inverse data processing means moving seismic data from forward data space (FDS) to inverse data space (IDS).The surface-related multiples and primaries can then be separated in the IDS,since surface-related multiples will form a focus region in the IDS.Muting the multiples energy can achieve the purpose of multiples elimination and avoid the damage to primaries energy during the process of adaptive subtraction.Randomized singular value decomposition (RSVD) is used to enhance calculation speed and improve the accuracy in the conversion of FDS to IDS.The synthetic shot record of the salt dome model shows that the relationship between primaries and multiples is simple and clear,and RSVD can easily eliminate multiples and save primaries energy.Compared with conventional multiples elimination methods and ordinary methods of multiples elimination in the inverse data space,this technique has an advantage of high calculation speed and reliable outcomes. 相似文献
68.
为探讨外来引种的互花米草(Spartina alterniflora Loisel)在我国海湾的扩展过程,根据1989-2010年遥感影像和野外观测数据,对罗源湾互花米草的分布特征进行分析,结果显示,对该区互花米草近20 a的扩展过程划分为3个阶段:前5 a其沿着高潮带平行于海岸线呈带状扩展;之后5 a在中潮带向湾内快速拓殖;后10 a则扩展缓慢,种群内部的空隙地逐渐被米草覆盖。截至2010年,罗源湾互花米草的总面积约为741.13 hm2。受潮滩环境分带性影响,罗源湾互花米草在高潮带平行于海岸线的扩展速度明显大于垂直于海岸线的扩展速度;在中潮带的快速扩展过程中互花米草倾向于先在潮沟两侧分布,这可能与归槽水和滩面摩阻作用有关,相比较,互花米草在浅洼地的扩展较滞后,该区域随着滩面的淤高过程逐渐被米草覆盖。在其整个扩展过程中,由于互花米草对潮流及悬浮颗粒的阻滞作用,使得其扩展前缘米草斑块和连续种群之间的光滩区成为悬浮颗粒及米草种子容易沉降的区域,互花米草易朝向该区域扩展。 相似文献
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Passive seismic has recently attracted a great deal of attention because non‐artificial source is used in subsurface imaging. The utilization of passive source is low cost compared with artificial‐source exploration. In general, constructing virtual shot gathers by using cross‐correlation is a preliminary step in passive seismic data processing, which provides the basis for applying conventional seismic processing methods. However, the subsurface structure is not uniformly illuminated by passive sources, which leads to that the ray path of passive seismic does not fit the hyperbolic hypothesis. Thereby, travel time is incorrect in the virtual shot gathers. Besides, the cross‐correlation results are contaminated by incoherent noise since the passive sources are always natural. Such noise is kinematically similar to seismic events and challenging to be attenuated, which will inevitably reduce the accuracy in the subsequent process. Although primary estimation for transient‐source seismic data has already been proposed, it is not feasible to noise‐source seismic data due to the incoherent noise. To overcome the above problems, we proposed to combine focal transform and local similarity into a highly integrated operator and then added it into the closed‐loop surface‐related multiple elimination based on the 3D L1‐norm sparse inversion framework. Results proved that the method was capable of reliably estimating noise‐free primaries and correcting travel time at far offsets for a foresaid virtual shot gathers in a simultaneous closed‐loop inversion manner. 相似文献