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1994-1996年,广州海洋地质调查局承担了南海西部石油公司在北部湾的部分高分辨率二维地震调查工程,调查船使用设备为1993年从美国引进的OYO地震仪(型号为DAS-1),施工过程前期进行了参数选择试验。本文介绍了高分辨地震调查参数选择依据、高分辨率二维采集中的一些注意事项、高分辨率二维采集中的一些注意事项、高分辨率地震资料的采集方法以及一些参数设定的原因。  相似文献   
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崩岗是中国花岗岩地区危害最大的一种土壤侵蚀方式,坡面防护是崩岗侵蚀治理的重要措施。为研究微生物诱导碳酸钙沉淀(MICP)技术在花岗岩崩岗侵蚀区冲刷防护中应用的可行性,以福建省崩岗最为发育的安溪县官桥镇花岗岩土质覆盖层为研究对象,进行降雨条件下微生物治理崩岗的模型试验研究。采用喷洒加固法对崩岗坡面进行处理,然后利用降雨模拟系统冲刷坡面,最后分析了MICP加固技术对泥沙产量及坡面侵蚀深度的影响。结果表明:与未加固边坡相比,MICP固化边坡泥沙产量由未加固的7648.43 g下降至266.61 g,较加固之前降低了96.51%;最大侵蚀深度由未加固的60 mm下降至除个别侵蚀坑外边坡表面基本未发生侵蚀。  相似文献   
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为明确降雨诱发滑坡机理及为防治措施确定依据,本文以福建省永泰县东门旗山滑坡为研究案例,在充分的地质勘探资料以及降雨期间滑坡位移监测数据的基础上,从内部与外部因素两个方面分析了滑坡的诱发机理,并通过数值方法对滑坡稳定性演化历程进行了反分析,将滑坡治理分为应急处理与长期加固两个阶段。在应急处理阶段,以拦排地表与地下水为主要工程措施,依据滑坡体不同部位滑动速率与降雨量的关系,验证推移式滑坡判断,得出先将排水措施布设于滑坡下部的结论;在长期加固方面,以抗滑桩为主要加固措施,以抗滑桩工程造价最低为优化目标,结合数值模拟与理论计算方法,得到最优抗滑桩设计方案为布桩于滑坡体中下部、桩径1.0 m、桩净距与中心距分别为2.0 m和3.0 m。  相似文献   
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为了进一步研究氮掺杂碳材料活化过硫酸盐降解4-氯苯酚的方法,首先以廉价易得的废弃工业糖浆作为碳源,以氨水作为氮源,利用溶胶-凝胶法合成了3种氮掺杂碳材料(NC-700,NC-800和NC-900),并利用扫描电子显微镜(SEM)、X射线衍射(XRD)、拉曼光谱(Raman)、X射线光电子能谱(XPS)等技术对氮掺杂碳材料进行表征分析;然后考察了NC-800投加量、过硫酸盐(PDS)投加量和初始pH等因素对4-氯苯酚去除率的影响,并进行了电子自旋共振(ESR)和自由基淬灭实验。结果表明:3种材料均可有效活化PDS降解4-氯苯酚,其中NC-800活化PDS去除4-氯苯酚效率最高;当NC-800投加量为100 mg/L、PDS投加量为5 mmol/L时,反应30 min后,50 mg/L的4-氯苯酚的总去除率达99.10%;初始pH对4-氯苯酚去除率无明显影响;NC-800活化过硫酸盐降解4-氯苯酚遵循非自由基途径,单线态氧为降解4-氯苯酚的活性物质。循环使用实验证明NC-800具有一定的稳定性,4次循环使用后,4-氯苯酚去除率仍可达到73.80%。  相似文献   
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Ye  Peng  Yu  Bin  Chen  Wenhong  Liu  Kan  Ye  Longzhen 《Natural Hazards》2022,113(2):965-995

The rainfall can contribute significantly to landslide events, especially in hilly areas. The landslide susceptibility map (LSM) usually helps to mitigate disasters. However, how to accurately predict the susceptibility of landslides is still a difficult point in the field of disaster research. In this study, five advanced machine learning technologies (MLTs), including the Light Gradient Boosting Machine, extreme gradient boost, categorical boosting (CatBoost), support vector machine, and random forest, are utilized to landslide susceptibility modeling and their capabilities are compared through evaluation indicators. The northern part of Yanping, Fujian Province, China, is selected as the research object, because this area experienced mass landslide events due to extremely heavy rainfall in June 2010, resulting in many casualties and a large number of public facilities destroyed. The influencing factors for landslides, namely topographic, hydrological, geologic and human activities, are prepared from various data sources based on the availability. Through the analysis of the actual situation in the study area, 13 suitable landslide condition factors are considered and the availability of relevant factors is checked according to the multicollinearity test. The landslide inventory including 631 samples in this study area is obtained from historical information, satellite data in Google earth and performed field surveys. The landslide inventory is randomly divided into two datasets for model training and testing with a 7:3 ratio. The area under the curve of ROC, accuracy rate, Kappa index and F1 score are applied to compare the MLTs capabilities. In this paper, the results of factor importance analysis show that the first three important condition factors are the distance to faults, the distance to drainages and the slope. According to the LSMs, in the study area, the central and western regions are at high and very high landslide susceptibility levels, while almost all the eastern and northeastern regions are at medium and low landslide susceptibility levels. The CatBoost model is a very promising technology in landslide research according to the evaluation results, which means that for landslide susceptibility research, gradient boosting algorithms may get more accurate results and show better prospects in the future. Finally, the results of this paper will contribute to environmental protection to a certain extent.

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6.
通过福建省重大灾难性地质灾害的历史资料归整、野外核查分析,总结灾害特征及影响作用因素,简要剖析成灾机理,以期为福建地质灾害防治提供指导。福建重大地质灾害特征包括时空分布集中、规模小危害重、滑坡泥石流灾害链形式及快速冲击效应等。其主要影响因素包括人类活动改造的局部汇水横纵坡形等微地貌、岩浆岩浅表层松散孔隙岩土体及罕见强降雨,表现为持续强降雨及地表水入渗软弱岩土体结构面,形成高孔隙水压及渗流动水压力形成滑坡泥石流灾害。  相似文献   
7.
We evaluated the ability of juvenile Amur sturgeon (Acipenser schrenckii) to osmoregulate and grow in saltwater. Hatchery-reared juveniles (mean weight 106.8 g, 5-month old) were transferred from freshwater to 10, 20, and 25 salinity saltwater over a period of 20 d. We measured the growth, serum osmolality, ion concentrations, and Na+/K+-ATPase activity. In addition, we prepared samples of gill tissue to quantify morphological changes in gill ultrastructure. Rearing in up to 25 saltwater for 30 d had no significant effect on growth. Similarly, serum osmolality and ion concentrations were similar to levels reported in other teleosts following acclimation to saltwater. Serum osmolality and Na+, Cl concentrations increased significantly with the initial increase in salinity. Afterwards, levels tended to stabilize and then decrease. Serum K+ levels did not change during acclimation to saltwater. Gill Na+/K+-ATPase activity increased initially as salinity was increased. However, the activity later decreased and, finally stabilized at 3.7±0.1 μmol Pi/mg·prot·h in 25 saltwater (1.6 times higher than the level in those in freshwater). In fish that were held only in freshwater, the chloride cells were located in the interlamellar regions of the filament and at the base of the lamella. Following acclimation to 25 saltwater for 30 d, the number and size of chloride cells increased significantly. Our results suggest that juvenile Amur sturgeon is able to tolerate, and grow in, relatively high concentrations of saltwater.  相似文献   
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