At‐a‐station hydraulic geometry relations, 2: calibration and testing     

Vijay P. Singh  Lan Zhang 《水文研究》2008,22(2):216-228

Using a large number of data sets obtained from various sources, the geometric relations derived in Part 1 are calibrated and verified using the split sampling approach. The calibration of parameters shows that the change in stream power is not shared equally among hydraulic variables and that the unevenness depends on the boundary conditions to be satisfied by the channel under consideration. The agreement between the observed values of the hydraulic variables and those predicted by the derived relations is close for the verification data set and lends credence to the hypotheses employed in this study. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

基于遥感数据和多因子评价的中国地区建设光伏电站的适宜性分析   总被引：1，自引：0，他引：1  

张乾  辛晓洲  张海龙  李月  李小军  裔传祥 《地球信息科学学报》2018,20(1):119-127

中国属于太阳能资源丰富的国家之一,光伏装机量位居世界第一,未来其装机量仍会不断增加。本文拟利用遥感技术获取区域太阳能资源的时空分布,采用多因子评价模型对中国地区大型光伏电站区域适宜性进行评估,以期为光伏电站的选址提供科学依据。结合太阳总辐射、日照时数的稳定程度、离路网的距离、离城镇的距离和坡向5个因子,通过设定海拔以及土地覆盖类型对应的限制区域,利用MuSyQ辐射产品、DEM、道路网数据、VIIRS夜间灯光数据、土地覆盖产品得到因子图层,使用层次分析法确定各因子在模型中的权重,借助GIS进行叠加分析并分为“低适宜”、“较适宜”、“适宜”、“非常适宜”和“限制区”5类,得到光伏电站建设的空间适宜性分布。研究结果表明,西北地区的适宜区占全国的53.0%,“非常适宜”区占全国的47.3%,其累计光伏电站装机量占全国的45.6%。建设光伏电站的“适宜”和“非常适宜”区面积的大小与装机量的多少没有明显的线性关系。“非常适宜”区作为光伏电站的最佳建设场所,光伏发电潜力大于2016年全国发电量的5倍。同时,国家政策制定的装机规模指标以及光电补贴政策对光伏电站的选址也起了一定的指向作用。  相似文献   

Modeling of twin-turbine systems with vertical axis tidal current turbines: Part I—Power output     

《Ocean Engineering》2010,37(7):627-637

Recent interest in the tidal current industry has driven development of the prototype from the stand-alone turbine to the twin-turbine system. In this paper, we develop a numerical model to systematically analyze the relationship between the power output and the configuration of a twin-turbine system. First, we present the design principle of the twin-turbine system. We then develop the numerical model for simulating the operation of the system, and validate the model by conducting towing tank experimental tests. We then use the model to predict the power output of the system. The results of this study show that the total power output of a twin-turbine system with optimal layout can be about 25% higher than two times that of a stand-alone turbine. We also discuss the hydrodynamic interaction between the two turbines under different configurations of the system. We conclude that the optimally configured counter-rotating system should be a side-by-side system, and that the optimally configured co-rotating system should have the downstream turbine partially in the wake of the upstream turbine, depending on the detailed configuration of the turbine.  相似文献   

钱塘江河口护塘丁坝的研究进展     

严盛  孙志林  赵渭军  林炳尧 《海洋学研究》2008,26(2):75-81

从作为河道整治或护岸的辅助建筑物的丁坝的原型观测、模型试验到工程实践等多种手段对钱塘江强潮河口段各个历史阶段护塘丁坝的研究成果进行了回顾和总结。钱塘江护塘丁坝技术在抗击强涌潮的过程中被不断推进、发展和创新,为钱塘江海塘的防护发挥了至关重要的作用。  相似文献   

Deriving hydrological signatures from soil moisture data     

Flora Branger  Hillary K. McMillan 《水文研究》2020,34(6):1410-1427

Soil moisture is an important variable in hydrological studies, but has been little used for model evaluation due to its high sensitivity to local conditions. We explore the possibility to derive hydrological signatures from soil moisture data that could overcome this limitation and be helpful for model evaluation. A set of eight hydrological signatures was built, encompassing long-term to short-term time scales. These signatures were tested according to robustness, representativeness and discriminatory power, using in situ data sets from New Zealand, including national network and experimental watershed data. Field capacity, type of soil moisture distribution, and starting dates of seasonal transitions typically meet the criteria, subject to uniform sensor depths and homogeneous land uses. Durations of seasonal transitions and event-based signatures showed higher variability and lower discriminatory power. In general, long-term signatures are more robust, more representative of large areas, and have a high discriminatory power, thus showing a good potential for use in diagnostic evaluation of regional models.  相似文献   

The preparation and antioxidant activity of glucosamine sulfate     

邢荣娥  刘松  王琳  蔡圣宝  于华华  冯金华  李鹏程 《中国海洋湖沼学报》2009,27(2):283-287

Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of chitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide (O-2)/hydroxyl (·OH) radicals scavenging, reducing power, iron ion chelating. The following results are obtained: first, glucosamine sulfa...  相似文献   

一种基于低功耗蓝牙的室内定位技术     

赵帅豪  王坚 《北京测绘》2020,(2):238-242

本文提出了一种基于蓝牙基站的室内定位解决方案。该技术方案中,蓝牙基站由低功耗蓝牙模块组成,在需要定位的室内空间均匀部署一定数量的蓝牙基站,每个蓝牙基站可以创建一个信号区域,并周期性地向外界广播自己独有的与位置信息对应的mac(media access control)地址和RSSI(Received Signal Strength Indication)值。当携带有蓝牙终端设备的用户进入该信号区域,就会接收蓝牙基站广播的RSSI值和mac地址,然后通过基于泰勒级数线性化的最小二乘迭代算法进行精确定位。实验结果表明,该系统定位精度在2.5 m以内,满足绝大多数的室内定位需求。  相似文献   

秋季红沿河核电站海域水龄分布及其对水母丰度分布的影响     

邱敏志  苏薇  姚庆祯  王彦涛  张广跃  许博超  张晓洁 《海洋学报》2020,42(4):122-127

本研究调查了秋季红沿河核电站海域镭、氡同位素的活度水平及分布情况，结合镭同位素表观年龄模型计算该海域的水体年龄，进而得出研究区域的水体运移方向，初步探讨了水母丰度分布与水体运移的相关关系。得到结论如下:(1)红沿河核电站海域表层水体中224Ra、226Ra及222Rn的活度水平分别为2.9～62.4 dpm/(100 L)，11.9～57.4 dpm/(100 L)及0.1～1.3 dpm/L，镭同位素活度呈现出近岸高、远岸低的分布趋势，氡同位素的分布则更大程度上受水温控制；(2)通过224Ra/226Ra表观年龄模型计算得出红沿河海域表层水体年龄范围介于0～16 d，平均年龄(10.9±3.6) d，水体主体流向为北偏东方向，流速为7.2 cm/s；(3)水母丰度分布与水体流向呈现出较为一致的对应关系，在主体流向方向上，水体年龄较大的海域水母丰度最高。  相似文献   

城乡一体,共建生态文明——北京周边地区的碧水、蓝天、绿化工程     

吴洁 《地球信息科学学报》2008,10(4):470-478

为落实绿色奥运的承诺,北京市与京津冀周边地区,以及内蒙古自治区、山西、山东等省(区),通力合作,城乡一体,调整产业结构及布局。推行资源节约、节能减排,优化环境,加强了保障能源、水源的基础设施;采取防尘、防沙、净化大气质量的工程措施。生态修复,成效显著。  相似文献   

滨海核电厂环境功能区调整问题分析   总被引：1，自引：0，他引：1  

李立立  郭佩芳  于宁 《海岸工程》2010,29(3):28-36

滨海核电站的建设导致电站附近海域现有使用功能与原有的环境功能出现矛盾,因此有必要进行环境功能区的调整。但由于核电发展在我国尚属起步阶段,相关方面的标准、规范尚不完善,因此在针对核电用海进行近岸海域环境功能区的调整过程中呈现出一些问题,例如,混合区的确定问题、余氯和放射性废液的排放问题以及数值模拟的科学性等。通过对这些问题进行分析,提出建议,为进一步完善国家相应的标准、规范提供依据,以便更好的保护海洋环境。  相似文献