Application of multimedia methodology for investigation of karst water in highland regions of Ha Giang Province, Vietnam     

Ngoc Thach Nguyen  Ngoc Hai Pham  Xuan Canh Pham  Thi Thuy Hang Nguyen  Van Lam Nguyen  Thi Thanh Thuy Duong 《Environmental Earth Sciences》2013,70(2):531-542

Ha Giang is one of the largest, northern border provinces of Vietnam, consisting of four districts: Yen Minh, Quan Ba, Dong Van and Meo Vac. This province features varied karst landscape of Carboniferous–Permian limestone. The region has been recognized by UNESCO as one of the 77 geological parks in the world and the second in Southeast Asia on 3 October 2012. In the dry season, little or no rain is recorded; therefore, surface water is very scarce. For this reason, proper delineation and exploitation of the groundwater resource is critical for sustainable water supply. This has been identified as an important challenge under the scientific project KC-08-10 in the national program KC-08. Remote sensing and GIS were used to decipher the signature of karst water in the highland of Ha Giang. Information layers generated were subjected to multi-criteria evaluation using analytic hierarchy process for decision making to identify ideal locations for groundwater prospecting. The study resulted in delineation of ten zones for all regions and 18 ideal drilling sites in Tam Son Town of Quan Ba District. Drilling and resistivity soundings were performed to assess the success of the interpretation. Deep resistivity survey confirmed low resistivity (200–300 Ωm) near the identified potential sites in Tam Son Town of Quan Ba District. Further, successful drilling at site LKTS1 with a discharge of 7–9 l/s is observed, proving the potential of this methodology for rapid exploration of groundwater in water-scare karst terrains of Vietnam.  相似文献   

Structural controls on the occurrence and morphology of karstified assemblages in northeastern Vietnam: a regional perspective     

Hai Thanh Tran  Bat Van Dang  Chi Kim Ngo  Que Dinh Hoang  Quyen Minh Nguyen 《Environmental Earth Sciences》2013,70(2):511-520

Karstified assemblages occur widely in, and distinctively shape, the geological landscape of the northeastern part of Vietnam. These carbonate rocks were deposited during three major periods of basinal evolution including: (1) Late Cambrian, (2) Early Devonian to Early Carboniferous, and (3) Carboniferous to Earliest Triassic. These sedimentary units contain primary sedimentary structures and have undergone numerous post-depositional geological processes including multiple deformational events, which can be regionally correlated. Several thrusting events and associated folding have led to significant thickening of the carbonate units. The subsequent post-thrusting cross-folding events, followed by several phases of brittle faulting and fracturing further modified the spatial geometry and outcrop of these rocks. The combination and interaction of the primary structures with those formed during the long-lived and complicated deformational history is an important controlling factor in local and regional hydrogeological systems in the region. The geological structures now recorded in the carbonate units ultimately govern the formation of the unique modern surface and sub-surface geomorphology of the karstic terrains in northeastern Vietnam. These structures should be further investigated in the context of water resource assessment and natural hazard prediction and mitigation.  相似文献   

磷灰石裂变径迹(AFT)研究进展   总被引：2，自引：0，他引：2  

周海  雷川 《西北地质》2013,(1):168-177

磷灰石裂变径迹是一种揭示岩石低温热年代学的有力工具。通过对国内外相关文献的广泛阅读,综述了磷灰石裂变径迹分析方法的原理、研究进展和地质意义及其在相关地质领域的应用。总结了影响磷灰石裂变径迹退火行为的主要影响因素,包括:①磷灰石的主要元素及238U的富集。②α衰变亏损。③压力及应力,以及实验观察时需要注意的问题。简要介绍了关于磷灰石裂变径迹退火过程的多元退火模型的建立及控制因素。对于目前的退火模型应用情况,结合前人研究总结了目前该方法的独特性及现行退火模型的不足之处。并对磷灰石裂变径迹在关于盆地热演化史、断层研究和造山带隆升分析(主要针对青藏高原隆升分析)中的应用做了简单、概要的剖析。  相似文献   

黄河流域绿色发展效率时空演进     

周福礼  海盼盼  王雪妮 《中国沙漠》2022,42(3):95-104

识别黄河流域绿色发展效率及其时空演进规律,有助于区域产业布局、环境规制与政策制定,进而实现黄河流域生态保护和高质量发展。针对黄河流域异质化发展,结合经济发展和环境治理的区域发展规律,构建多周期两阶段DEA模型（Multi-period two-stage DEA model）,通过测算绿色经济效率与绿色创新效率,实现黄河流域省市的绿色发展效率测度,同时借助ArcGIS10.6软件对黄河流域省域绿色发展的时空格局进行了动态演进并分析其发展路径。结果表明：黄河流域空间维度呈现上游较差、中游一般、下游最优的发展不均衡现状;时间维度呈现“W”型波动式上升趋势,但整体一般;存在省份绿色发展水平较高、黄河段城市却较差的发展不一致现象。针对黄河流域省市的各种发展情境,从省市协同治理、政府引导、产业结构、科技研发、税收政策等方面提出了建议。  相似文献   

制备工艺对低温烧结Ni-Cu-Zn铁氧体/BaTiO_3复合材料性能的影响     

凌味未  许诚昕  马文英  聂海  陈祝 《成都信息工程学院学报》2014,(2):117-120

采用2种复合工艺流程在900°C和950°C制备了适用于低温共烧陶瓷(LTCC)工艺的Ni-Cu-Zn铁氧体/BaTiO3复合材料。对比研究了不同工艺流程下,烧结温度及助剂用量变化对复合体系烧结性能和电磁性能的影响。900°C烧结时,在铁氧体预烧前添加BaTiO3(工艺流程Ⅱ)制备的复合材料比在铁氧体预烧后添加BaTiO3(工艺流程Ⅰ)制备的复合材料有更高的烧结密度(5.40g/cm3)和Snoek乘积(5.56GHz);950°C烧结时,工艺流程Ⅱ制备的复合材料的介电性能优于工艺流程Ⅰ制备的。  相似文献   

Interdecadal change in the Northern Hemisphere seasonal climate prediction skill: part II. predictability and prediction skill     

XiaoJing Jia  June-Yi Lee  Hai Lin  Harry Hendon  Kyung-Ja Ha 《Climate Dynamics》2014,43(5-6):1611-1630

The interdecadal change in seasonal predictability and numerical models’ seasonal forecast skill in the Northern Hemisphere are examined using both observations and the seasonal hindcast from six coupled atmosphere-ocean climate models from the 21 period of 1960–1980 (P1) to that of 1981–2001 (P2). It is shown that the one-month lead seasonal forecast skill of the six models’ multi-model ensemble is significantly increased from P1 to P2 for all four seasons. We identify four possible reasons accounting for the interdecadal change of the seasonal forecast skill. Firstly, the numerical model’s ability to simulate the mean state, the time variability and the spatial structures of the sea surface temperature and precipitation over the tropical Pacific is improved in P2 compared to P1. Secondly, an examination of the potential predictability of the atmosphere, estimated by the ratio of the total variance to the variance due to the internal dynamics of the model atmosphere, reveals that the atmospheric potential predictability is significantly increased after 1980s which is mainly due to an increased influence of El Niño-Southern Oscillation signal over the North Pacific and North American regions. Thirdly, the long-term climate trends in the atmosphere are found to contribute, to some extent, to the increased seasonal forecast skill especially over the Eurasian regions. Finally, the improved ocean observations in P2 may provide better initial conditions for the coupled models’ seasonal forecast.  相似文献   

北斗卫星定轨中的常用光压模型比较     

陈晨  李建文  罗福龙  黄克亮  黄海 《测绘科学技术学报》2014,(5)

利用北斗精密星历作为伪观测值拟合了伯尔尼(BERN)光压模型和球光压模型的光压参数,并利用所求参数分别进行了轨道外推。通过分析轨道拟合和外推精度得到如下结论:在1 d的弧段上,BERN模型对于3类卫星GEO,IGSO和MEO的拟合精度相当且精度优于10 cm;球模型对于GEO和IGSO的轨道拟合精度相当且精度优于50 cm,明显低于其对MEO的拟合精度;对于GEO和MEO以及IGSO卫星6号星,利用BERN模型得到的外推轨道比利用球模型得到的外推轨道精度高;但对于8号,9号及10号IGSO卫星而言,利用球模型得到的外推轨道比利用BERN模型得到的外推轨道精度高。  相似文献   

Prediction Model of Kinetic Energy Conversion of Tandem Dual-Oscillator Based on Flow-Induced Vibration Experiment     

Bai  Xu  Sun  Meng  Han  Chuan-yu  Sun  Hai 《中国海洋工程》2022,36(5):707-719

China Ocean Engineering - Flow-induced vibration energy harvesting devices typically use an elastically supported body immersed in an oncoming flow to convert the sea and river current’s...  相似文献   

房产全生命周期测绘管理系统开发     

张金山  杨海  全丽娟  芦园园 《测绘与空间地理信息》2013,(9)

房产作为社会最重要的财富,要经历规划、预售、竣工、拆迁等阶段,在每一阶段均要进行房产面积的测算。现在房产测绘在各阶段的测绘方法与计算规范不尽相同,成果的比较核对与共享大部分还处在手工阶段,这给房产测绘管理带来了很大的不确定性,也大大增加了测绘成本和可能带来的纠分。为此,开发一套针对房产全生命周期的测绘管理办法与系统,提高房产调查与测绘的效率,降低成本,保证成果的质量与权威性,实现各管理部门的信息共享,为城市建设提供决策支持。  相似文献   

Water quality improvement through five constructed serial wetland cells and its implications on nonpoint-source pollution control     

Z. Jia  S. Tang  W. Luo  Y. Hai 《水文科学杂志》2013,58(16):2946-2956

ABSTRACT

Constructed wetlands can be used for reducing nonpoint-source pollution and providing ecological services in a watershed. This paper presents a field monitoring study on water quality improvement in constructed wetlands of five cells in series. The wetland system covers 59.9 ha, or 0.08% of the watershed area; it diverts 7.3 million m³ (hm³) water (or 4.3% annual flow) from a degraded river. The results showed that the hydraulic retention times (HRT) of the five cells ranged from 5 to 15 days, 18.4% inflow was lost to seepage and increased evapotranspiration (ET) in the wetlands; the wetlands retained 99.1% total suspended solids (TSS), 60.9% total phosphorus (TP), and 54.4% total nitrogen (TN) from the inflow. Major reductions of TSS and TP were observed in the first two large cells that occupied 57% of the total wetland area. The smaller cells did not show advantages over the bigger ones in pollutant retention as reported in some studies. Although significant water quality benefit can be achieved by the constructed wetlands, the increased water loss may be a concern, particularly in dry regions.