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151.
QFGZ型潜孔锤反循环跟管钻头的研制 总被引:2,自引:2,他引:0
为实现在复杂地层用同步跟管钻进工艺钻凿直径较大的桩孔和水井,设计了一种气动潜孔锤反循环跟管钻进钻头。介绍了该钻头的结构组成、工作原理和设计特点。与常规设计相比,该新型钻头流道设计可以增强排渣效果,保持孔底干净,减少重复破碎,提高钻进效率;边齿数量较多,耐磨损能力强,有利于提高使用寿命。 相似文献
152.
Efficient hybrid breaching‐filling sink removal methods for flow path enforcement in digital elevation models
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John B. Lindsay 《水文研究》2016,30(6):846-857
Digital elevation models (DEMs) that are used in hydrological applications must be processed to remove sinks, mainly topographic depressions. Flow enforcement techniques include filling methods, which raise elevations within depressions, breaching, which carves channels through blockages, and hybrid methods. Despite previous research demonstrating the large impact to DEMs and subsequent analyses of depression filling, it is common practice apply this technique to flow enforcement. This is partly because of the greater efficiency of depression filling tools compared to breaching counterparts, which often limits breaching to applications of small‐ to moderate‐sized DEMs. A new hybrid flow enforcement algorithm is presented in this study. The method can be run in complete breaching, selective breaching (either breached or filled), or constrained breaching (partial breaching) modes, allowing for greater flexibility in how practitioners enforce continuous flow paths. Algorithm performance was tested with DEMs of varying topography, spatial extents, and resolution. The sites included three moderate sized DEMs (52 000 000 to 190 000 000 cells) and three massive DEMs of the Iberian Peninsula, and the Amazon and Nile River basins, the largest containing nearly one billion cells. In complete breaching mode, the new algorithm required 87% of the time needed by a filling method to process the test DEMs, while the selective breaching and constrained breaching modes, operating with maximum breach depth constraints, increased run times by 8% and 27% respectively. Therefore, the new algorithm offers comparable performance to filling and the ability to process massive topographic data sets, while giving practitioners greater flexibility and lowering DEM impact. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
153.
长春市高家窝棚—双泉眼矿区为松软煤系地层,采用绳索取心液动冲击回转钻进方法,选择加大钻孔孔壁与钻杆环状间隙的钻孔结构;经实验选择以粘土、共聚物、植物胶、铵盐、腐植酸钾、磺化沥青、聚丙烯酸钾等材料配制的冲洗液,并加强冲洗液的日常维护管理;配备离心式除泥机;套管丝扣连接处涂抹松香(粘结剂),并用薄钢板焊接补强丝扣连接处,防止套管脱扣等技术措施,成功地完成了2个深孔的钻孔施工,终孔深度分别为1112.45 m(ZK6405孔)和1359.95 m(ZK3201孔),岩心采取率达到100%,煤心样品没有燃烧破坏现象,较好地满足了地质的要求。 相似文献
154.
为去除农村家庭饮用地下水中的硝酸盐,以农村自酿米酒为碳源,利用简易的沙桶装置开展了反硝化去除硝酸盐的实验,对比了不同乙醇浓度下的反硝化效果。实验结果表明,以沙桶为实验装置,自酿米酒为碳源,在家庭中异位反硝化去除抽取地下水中的硝酸盐方法是有效果,易操作的。硝酸盐的去除率和C/N质量比有直接关系,当C/N质量比大于1.99时,硝酸盐去除率达99%,亚硝酸盐零积累,但易积累乙酸盐;当C/N质量比为0.89时,硝酸盐去除率达99%,生成物亚硝酸盐浓度远高于国家饮用水限值(1 mg/L);当C/N质量比为0.43时,反硝化过程不彻底,硝酸盐去除率不高,且易生成溶度较高的亚硝酸盐。溶解氧的存在不会对反硝化产生显著影响。米酒和硝酸盐之间的C/N最佳比例,宜大于本次实验的0.89,小于1.99,利用农村自酿米酒作为碳源去除地下水中硝酸盐是可行的。 相似文献
155.
采用一步溶剂热法制备了活化半焦负载还原氧化石墨烯掺杂二氧化钛新型负载型光催化剂,即rGO-TiO2/ASC。分别考察了高温水汽活化方法和还原氧化石墨烯rGO掺杂量对光催化脱硝性能的影响,并进一步探究光照条件、烟气氧含量和烟气湿度对NO氧化脱除的作用,得出新型负载型光催化剂rGO-TiO2/ASC光催化脱硝过程主要过程。结果表明,5%水汽高温活化半焦ASC的脱硝效率最高,反应4h后可达52%。rGO负载量为8%时,负载型光催化剂rGOTiO2/ASC脱硝性能4h后转化率达70.68%。有无O2对脱硝率影响较大,有无光照对其影响次之。无H2O时,脱硝率呈现先平稳后下降的趋势。新型负载型光催化剂rGO-TiO2/ASC的脱硝过程由光催化活性组分rGO-TiO2/ASC的光催化氧化和载体部分ASC的常规氧化两部分组成。 相似文献
156.
研究了人工湿地循环处理哈氏仿对虾(Parapenaeopsis hardwickii)高盐度(21.1-23.3)养殖废水的净化效果。人工湿地对高盐度养殖废水中各水质指标去除率为:总氨氮66.7%,亚硝酸盐80.0%,化学需氧量12.5%,浊度69.1%,硝酸盐-12.1%,总氮3.5%,总磷0.0%。养殖池水质状况良好。在试验负载范围内,湿地对总氨氮、亚硝酸盐、浊度的去除量随进水污染负载量的增加而增加。研究表明:人工湿地能持续有效降低哈氏仿对虾养殖废水中的主要水质因子浓度。 相似文献
157.
Mussel farming as a nutrient reduction measure in the Baltic Sea: consideration of nutrient biogeochemical cycles 总被引:1,自引:0,他引:1
Nutrient loads from the land to the sea must be reduced to combat coastal eutrophication. It has been suggested that further mitigation efforts are needed in the brackish Baltic Sea to decrease nutrients, especially in eutrophic coastal areas. Mussel farming is a potential measure to remove nutrients directly from the sea. Mussels consume phytoplankton containing nitrogen (N) and phosphorus (P); when the mussels are harvested these nutrients are removed from the aquatic system. However, sedimentation of organic material in faeces and pseudo-faeces below a mussel farm consumes oxygen and can lead to hypoxic or even anoxic sediments causing an increased sediment release of ammonium and phosphate. Moreover, N losses from denitrification can be reduced due to low oxygen and reduced numbers of bioturbating organisms. To reveal if mussel farming is a cost-effective mitigation measure in the Baltic Sea the potential for enhanced sediment nutrient release must be assessed. 相似文献
158.
159.
大陆岩石圈的增厚及对流剥离对青藏高原隆升的影响 总被引:1,自引:0,他引:1
伴随着印度板块对欧亚板块南缘的碰撞、挤压,青藏高原地壳及下伏地幔岩石圈的厚度增加了1倍。增厚岩石圈热结构的变化可导致高原海拨下降约1500m。其对流剥离并被较热的软流圈物质替代可用以解释青藏高原自8百万年或3百万年前开始的快速隆升。大陆岩石圈的增厚及热结构变化和对流剥离可能是青藏高原自9百万年前开始的夷平—快速隆升过程的主导控制因素。 相似文献
160.
Yu-Fang Chiu Samkele S. Tfwala Yung-Ching Hsu Yen-Yu Chiu Chen-Yang Lee Su-Chin Chen 《地球表面变化过程与地形》2021,46(13):2527-2539
Sediment flushing and the morphological responses to the procedure of check dam removal are still unclear. Following laboratory experiments that revealed three stages (deepening, widening, and volume release) of check dam adjustment, a check dam built in 2007 at Landao Creek in central Taiwan was adjusted in 2015 by removing central bars and cutting 2.5 m from the middle two piers (stage 1 + 2), with the purpose of regulating sediment transfer and keeping the thalweg at the center of the channel, while also preventing hill slope toe erosion. In 2019, four central piers were removed (stage 3) to increase the volume of sediment released. Annual surveys were conducted after the initial adjustment in 2015 through to 2020 using unmanned aerial vehicles (UAVs). The check dam adjustments revealed that the channel had narrowed and stabilized as indicated by regenerating riparian vegetation. Additionally, distinct terraces had formed on the hill slope toes of the creek channel in proximity to the check dam. The meander upstream weakened following the dam adjustments. This study combining laboratory experiments with actual field observation contributed immensely to check dam decommissioning. Additionally, this study illustrated how an adjustable check dam may aid regulation of sediment transport and thereby sediment balance. It can be adjusted accordingly based on the prevailing channel condition. 相似文献