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851.
采用有限元法模拟计算了液压光电测压计传压盒的受力和变形情况,对传压盒的结构进行了优化分析。介绍了液压光电测压计的标定试验、模拟试验及其结果的分析处理,阐述了这种具有极大推广使用价值的发明专利产品的特性及适用范围。 相似文献
852.
在黄土塬区或复杂的黄土地形区作煤田地震勘探工作需要进行沿沟弯线地震施工技术的研究。通过项目实施,对弯线技术的应用有所见解,着重分析了弯曲测线在煤田地震勘探中的主要采集参数选择和施工技术措施,并介绍了地震弯线技术的应用效果。 相似文献
853.
854.
This paper provides a comparison of gauge and radar precipitation data sources during an extreme hydrological event. November–December 2006 was selected as a time period of intense rainfall and large river flows for the Severn Uplands, an upland catchment in the United Kingdom. A comparison between gauge and radar precipitation time‐series records for the event indicated discrepancies between data sources, particularly in areas of higher elevation. The HEC‐HMS rainfall‐runoff model was selected to assess the accuracy of the precipitation to simulate river flows for the extreme event. Gauge, radar and gauge‐corrected radar rainfall were used as model inputs. Universal cokriging was used to geostatistically interpolate gauge data with radar and elevation data as covariates. This interpolated layer was used to calculate the mean‐field bias and correct the radar composites. Results indicated that gauge‐ and gauge‐corrected radar‐driven models replicated flows adequately for the extreme event. Gauge‐corrected flow predictions produced an increase in flow prediction accuracy when compared with the raw radar, yet predictions were comparative in accuracy to those using the interpolated gauge network. Subsequent investigations suggested this was due to an adequate spatial and temporal resolution of the precipitation gauge network within the Severn Uplands. Results suggested that the six rain gauges could adequately represent precipitation variability of the Severn Uplands to predict flows at an approximately equal accuracy to that obtained by radar. Temporally, radar produced an increase in flow prediction accuracy in mountainous reaches once the gauge time step was in excessive of an hourly interval. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
855.
The present model permits simulation of any geographic region and the symmetrical or random positioning of any number of rain gauges. The operator has the option of entering precipitation parameters: rain cell diameter, duration, rain swath length, vector angle, and precipitation amount for any number of discrete showers. In a series of computations the model generates (1) a random first echo location and resulting rain swath, which is superimposed on a specific grid of rain gauges; (2) the number of rain gauge receiving a hit; and (3) the number of undetected rain events within an area.By use of a portion of the Iowa climatological rain gauge network and parameters derived from radar and rain gauge observations the model shows that only 7% of single cell showers are detected by the existing sampling grid.Journal Paper No. J-10378 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA 50011. Project 2449.A portion of this paper was presented at the 93rd Annual Meeting of the Iowa Academy of Science, April 1981. 相似文献
856.
趋势面分析在洪山殿矿区构造和厚煤带分布研究中的应用 总被引:1,自引:0,他引:1
通过对洪山殿矿区龙潭组Ⅳ煤层底板高程趋势面分析,认为在洪山殿矿区存在多方向的褶皱及其叠加。与本区受到多期次的构造应力场作用相吻合。而通过对Ⅳ煤层厚趋势面分析,得出的煤层厚度在褶皱轴部加厚,翼部变薄的规律性可用来预测矿区Ⅳ煤层厚度和构造的变化。 相似文献
857.
地质灾害分布范围广,应用卫星图像监测地质灾害是一种可行的方法,泥石流沟小流域面积一般达到平方公里的数量级,可以由卫星图像观察到,TM数据有7个波段,各个波段图像的标准差是不同的,我们计算了泥石流沟各波段的标准差,按大小排成一个序列,发现地理条件相同,标准序列也相同,在一定尺度范围内,各泥石流沟的标准差序列和周围不一致,表示该构处于特殊的发育阶段,有爆发泥石流的危险,应用上述方法,对甘肃主要泥石流分布区的典型泥石流沟进行了分析,认为这是监测泥石流的可行方法。 相似文献
858.
859.
We have computed estimates of the rate of vertical land motion in the Mediterranean Sea from differences of sea level heights measured by the TOPEX/Poseidon radar altimeter and by a set of tide gauge stations. The comparison of data at 16 tide gauges, using both hourly data from local datasets and monthly data from the PSMSL dataset, shows a general agreement, significant differences are found at only one location. Differences of near-simultaneous, monthly and deseasoned monthly sea level height time-series have been considered in order to reduce the error in the estimated linear-term. In a subset of 23 tide gauge stations the mean accuracy of the estimated vertical rates is 2.3 ± 0.8 mm/yr. Results for various stations are in agreement with estimates of vertical land motion from geodetic methods. A comparison with vertical motion estimated by GPS at four locations shows a mean difference of -0.04 ± 1.8 mm/yr, however the length of the GPS time-series and the number of locations are too small to draw general conclusions. 相似文献
860.
Shigeru Aoki Kazuo Shibuya Akihiro Masuyama Taku Ozawa Koichiro Doi 《Journal of Oceanography》2002,58(3):519-523
Global Positioning System (GPS) measurements of the vertical displacement of fast ice near Syowa Station, Antarctica, were
conducted between April and December 1998 to evaluate measurements of sea level variation derived with a conventional bottom
pressure gauge (BPG). The BPG-derived sea level revealed a seasonal variation of about 0.13 m, with a high in April–June and
a low in November–December. The GPS-derived sea level, combined with observed sea ice thickness, supported the BPG result,
with an RMS error of 0.007 m. Our result also demonstrates that GPS is a powerful technique for monitoring sea level variations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献