两点后方交会在工业检测中的应用研究     

李法礼  韩万围  王智 《四川测绘》2010,33(4):176-177

用全站仪检测工业设备时经常需要移站测量，本文根据移站前后两个公共点利用后方交会求取移站后测站点坐标，通过解平面三角形求取测站点平面坐标，采用距离进行加权平均求取高程值，通过实验验证了该方法的可行性。  相似文献   

Industry participation in stock assessment: the New Zealand SNA1 snapper (Pagrus auratus) fishery     

Mark N. Maunder  Paul J. Starr   《Marine Policy》2002,26(6)

We describe industry funded contributions to the assessment of the SNA1 snapper (Pagrus auratus) fishery during the 1990s and discuss the advantages and disadvantages of industry funded research. We also provide background on the history of fisheries management in New Zealand, on the current assessment and management processes, and on the SNA1 snapper fishery. In the SNA1 fishery, the contributions of industry and the cooperation with Government scientists has resulted in high quality assessments. In our opinion, the advantages of industry funded research out weigh the disadvantages and suggest that industry funded assessments are highly desirable and should be an integral part of any management system.  相似文献   

A Study of the Extended-range Forecast for the Low Frequency Temperature and High Temperature Weather over the Lower Reaches of Yangtze River Valley in Summer     

Qiuming Yang 《地球科学进展》2018,33(4):385-395

Based on the observational data, the variations of Intraseasonal Oscillation (ISO) of the daily temperatures and its relationships to the high temperature in summer over the lower reaches of the Yangtze River Valley (LYRV) were studied for the period of 1979-2011. It is found that the daily temperatures over LYRV in May-August was mainly of periodic oscillations of 1525, 3060 and 6070 days, and the interannual variation of the intensity of its 3060-day oscillation had a strongly positive correlation with the number of days with daily highest temperature over 35 ℃ in July-August. Low frequency components of daily temperature in the LYRV, and the principal components of the Eastern Asian 850 hPa low frequency temperature, over a time period ranging from 1979 to 2000, were used to establish the Extended Complex Autoregressive model (ECAR) on an extended-range forecast of the 3060-day low frequency temperature over the LYRV. A 11-year independent real-time extended-range forecast was conducted on the extended-range forecast of low frequency component of the temperature over the LYRV in May-August, for the period ranging from 2001 to 2011. These experimental results show that this ECAR model, which is based on a data-driven model, has a good forecast skill at the lead time of approximately 23 days, with a forecast ability superior to the traditional autoregressive (AR) model. Hence, the development and variation of the leading 3060-day modes for the Eastern Asian 850 hPa low frequency temperatures and temporal evolutions of their relationships to low frequency components of the temperature over the LYRV in summer are very helpful in predicting the persistent high temperature over the LYRV at a 20 to 25 days lead.  相似文献   

Response characteristics of plunge pool slabs of Xiaxiluodu Hydropower Station to flood discharge pulsating-pressure under valley deformation conditions     

《地震研究进展（英文）》2022,2(4):100136

The key problem of the energy dissipation scheme of the arch dam body flood discharge and plunge pool below the dam is the stability problem of the plunge pool slab. As the protection structure of the underwater bed, the plunge pool slab bears the continuous impact of high-speed water flow. The hourly average dynamic water pressure on the slab is one of the main loads directly affecting the stability of the slab and is the main factor causing its erosion destruction. After the impoundment of the Xiluodu Hydropower Station, the measuring line of valley width in the plunge pool area has been continuously shrinking. By 2020, the cumulative shrinking value is about 80 ​mm. In light of the general background condition of valley shrinkage, daily inspection, annual detailed inspection, underwater inspection and drainage inspection of the plunge pool found that the plunge pool has experienced different degrees of damage, which greatly influences the long-term safety stability of the plunge pool. In this paper, the prototype observation data of flood discharge is used as the input load of pulsating-pressure, and the stress and displacement distribution of the plunge pool structure under the vibration load of flood discharge is analyzed under the condition that the stress and strain state of the plunge pool is changed under the influence of valley displacement. The results show that the stress, strain, and displacement distribution of the plunge pool are mainly caused by valley deformation, the vibration caused by flood discharge is little in influence, and the impact effect of deep hole flood discharge tongue on the plunge pool slab is weak.  相似文献   

高泉沟流域产流产沙的降水特征因子分析     

焦金鱼 《地质灾害与环境保护》2012,23(2):86-90

高泉沟流域属于黄土丘陵沟壑区。运用灰色关联与相关系数分析法,分析影响该流域坡面产流产沙的降水特征因子。结果表明对黄土丘陵沟壑区产生径流贡献最大的因子是降雨量;对土壤侵蚀量贡献最大的因子是降雨量半小时雨强复合因子。因此,降雨量的多少是影响本区产流产沙最关键的因素。  相似文献   

雅鲁藏布江河谷加查-米林段沙丘成因     

刘慧  李晓英  夏翠珍  姚正毅 《中国沙漠》2020,40(3):16-26

加查-米林段位于雅鲁藏布江河谷中游下段，分布沙丘89片。通过实地考察、遥感卫星影像解译、DEM分析、粒度分析等方法对加查-米林段沙丘成因进行分析。结果表明：依据沙丘沙物质来源可将加查-米林段沙丘划分为河漫滩型沙丘、阶地型沙丘和谷坡型沙丘。河漫滩型沙丘形成与雅鲁藏布江水位关系密切。丰水期洪水淹没河漫滩，泥沙沉积；枯水期水位降低，泥沙出露，经风的吹蚀、搬运、堆积形成河漫滩型沙丘。阶地型沙丘和谷坡型沙丘形成与表层覆盖的黄土层（粉质砂土）破坏有关。雅鲁藏布江不断下切，在阶地及谷坡不同高度残留古河流冲积沙，遭受风蚀后风蚀堆积物形成古沙丘。因环境演变，古沙丘表面沉积黄土，形成致密坚硬的黄土层，不易被风吹蚀，成为古沙丘的保护层。黄土层受风蚀、水蚀及人类活动破坏，导致下伏古沙丘裸露，形成现代流动沙丘。  相似文献   

水产养殖遥感监测及信息自动提取方法研究   总被引：2，自引：0，他引：2  

关学彬  张翠萍  蒋菊生  曹建华 《国土资源遥感》2009,(2):41-44

以海南省文昌地区为例,在沿海地区尝试利用遥感监测的手段提取水产养殖地块和面积.采用面向对象的分类方法进行监测,取得了理想效果,同时也提出了提高分类精度的建议.  相似文献   

Dissolved aluminium and the silicon cycle in the Arctic Ocean   总被引：1，自引：0，他引：1  

R. Middag  H.J.W. de Baar  P. Laan  K. Bakker 《Marine Chemistry》2009,115(3-4):176-195

Concentrations of dissolved (0.2 µm filtered) aluminium (Al) have been determined for the first time in the Eurasian part of the Arctic Ocean over the entire water column during expedition ARK XXII/2 aboard R.V. Polarstern (2007). An unprecedented number of 666 samples was analysed for 44 stations along 5 ocean transects. Dissolved Al in surface layer water (SLW) was very low, close to 1 nM, with lowest SLW concentrations towards the Canadian part of the Arctic Ocean and higher values adjacent to and in the shelf seas. The low SLW concentrations indicate no or little influence from aeolian dust input. Dissolved Al showed a nutrient-type increase with depth up to 28 nM, but large differences existed between the different deep Arctic basins. The differences in concentrations of Al between water masses and basins could largely be related to the different origins of the water masses. In the SLW and intermediate water layers, Atlantic and Pacific inflows were of importance. Deep shelf convection appeared to influence the Al distribution in the deep Eurasian Basin. The Al distribution of the deep Makarov Basin provides evidence for Eurasian Basin water inflow into the deep Makarov Basin. A strong correlation between Al and Silicon (Si) was observed in all basins. This correlation and the nutrient-like profile indicate a strong biological influence on the cycling and distribution of Al. The biological influence can be direct by the incorporation of Al in biogenic silica, indirect by preferential scavenging of Al onto biogenic siliceous particles, or by a combination of both processes. From the slope of the overall Al–Si relationship in the intermediate water layer (AIDW; ~ 200–2000 m depth), an Al/Si ratio of 2.2 atoms Al per 1000 atoms Si was derived. This ratio is consistent with the range of previously reported Al/Si uptake ratio in biogenic opal frustules of diatoms. In the deepest waters (>2000 m depth) a steeper slope of the Al–Si relationship of 7.4 to 13 atoms Al per 1000 atoms Si likely results from entrainment of cold shelf water into the deep basins, carrying the signal of dissolution of terrigenous particles with a much higher Al:Si ratio of crustal abundance. Only a small enrichment with such crustal Al and Si component may readily account for the higher Al:Si slope in the deepest waters.  相似文献   

Developing a conceptual model of marine farming in New Zealand     

Hamish G. Rennie  Roger White  Lars Brabyn 《Marine Policy》2009

Survey and Geographic Information System (GIS) data analysis describes the relative influence of biophysical and human variables on site choices made by marine farmers in New Zealand. Community conflicts have grown in importance in determining farm location and different government planning strategies leave distinct signature patterns. Recent legislation empowers local governments to choose among three strategies for future regional aquaculture development. This paper suggests each strategy could result in different spatial outcomes. Simulation modelling of the type described here can provide a better understanding of farmer responses to management approaches and the range of futures that could result from planning choices made today.  相似文献   

Monitoring salmon aquaculture waste: The contribution of First Nations’ rights, knowledge, and practices in British Columbia, Canada     

Robyn Heaslip   《Marine Policy》2008,32(6):988-996

British Columbia's current approach to monitoring salmon aquaculture waste is disconnected from political and legal trends towards the recognition of Aboriginal rights in Canada. Drawing on insights from collaborative monitoring in northern Canada and interviews with 23 Kwakwaka’wakw clam-diggers and cultural specialists (2006–2007), preliminary directions for integrating First Nations’ values, knowledge and stewardship practices into marine environmental monitoring are identified. Kwakwaka’wakw monitoring practices include the use of qualitative individual, community and population scale indicators and the integration of traditional knowledge as baseline data about the healthy conditions of traditional food resources.  相似文献