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黄河(内蒙古段)弯道卡冰过程及数值模拟研究 被引量:8
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作者 李超 李畅游 李红芳 《水力发电学报》 EI CSCD 北大核心 2015年第10期103-110,共8页
野外观测发现天然河流弯道处是封河期最易形成卡冰结坝的位置,冰坝的形成会壅高上游水位,严重时发生凌洪灾害。因此,研究弯道处卡冰过程,分析卡冰结坝机理是河冰研究的关键问题之一。本文中,通过对2013—2014年冬季不同形态弯道河冰过... 野外观测发现天然河流弯道处是封河期最易形成卡冰结坝的位置,冰坝的形成会壅高上游水位,严重时发生凌洪灾害。因此,研究弯道处卡冰过程,分析卡冰结坝机理是河冰研究的关键问题之一。本文中,通过对2013—2014年冬季不同形态弯道河冰过程的野外观测,分析了各种形态弯道卡冰结坝的过程、特性。基于二维Dyna RICE河冰动力学模型对三湖河道弯道表面冰输移进行模拟。结果表明弯道卡冰位置常发生在弯道出口河面束窄处,弯道处上游流凌密度、上游及下游的水力条件和河道形态是影响弯道卡冰结坝的关键因素。本研究对于确定冰坝初始形成位置,为进一步提出防凌减灾措施提供技术支持。 展开更多
关键词 黄河 弯道 过程 卡冰 DynaRICE河模型
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黄河头道拐段冰输移及堆积过程数值模拟 被引量:1
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作者 李超 冀雪飞 +1 位作者 赵水霞 Hung Tao Shen 《水利学报》 EI CSCD 北大核心 2023年第4期474-485,共12页
头道拐河段因其特殊的河道形态及地理位置而成为黄河内蒙古段最易形成冰坝的河段,研究该河段河冰输移及堆积过程是理解内蒙古段河冰过程及卡冰结坝作用机理的关键。本文基于耦合的二维有限元水动力学模型和DPM(Discrete Parcel Method)... 头道拐河段因其特殊的河道形态及地理位置而成为黄河内蒙古段最易形成冰坝的河段,研究该河段河冰输移及堆积过程是理解内蒙古段河冰过程及卡冰结坝作用机理的关键。本文基于耦合的二维有限元水动力学模型和DPM(Discrete Parcel Method)河冰动力学模型,模拟了黄河头道拐河段2020—2021年冬季封河过程并进行了验证,讨论了不同水力条件、上游流凌密集度及河道形态对封河过程的影响。结果表明:相比于官牛犋弯道,河道弯曲率大、束窄程度高的什四份子弯道更易形成卡冰,且流量越小,卡冰作用越明显,冰盖向上游发展速度越快。河道流凌密集度小于0.4时,各种流量下研究河段未发生卡冰;流凌密集度增大至0.4,表面流冰首先在弯曲率系数较大的什四份子弯道处形成卡冰,随着流凌密集度和流量的进一步增大,下潜并输移到下游的流凌也会在官牛犋弯道形成卡冰,因此,头道拐河段形成卡冰的流凌密集度临界条件为0.4。应用冰水耦合二维动力学模型可以很好地模拟天然河道河冰输移、堆积过程中河道的水力特性、冰厚增长及封河形态,揭示了影响河冰过程的相关因素及作用机理,为黄河内蒙古段防凌减灾工作提供技术支撑。 展开更多
关键词 黄河内蒙古段 输移 卡冰结坝 动力学 数值模拟
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黄河口河道演变规律探讨 被引量:3
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作者 王万战 张俊华 《水利水电科技进展》 CSCD 北大核心 2006年第2期5-9,20,共6页
通过分析黄河口河道在纵剖面、横断面、河型等方面的演变过程,总结归纳出黄河口河道的演变规律。指出:黄河口泥沙在潮汐涨落等因素影响下,河口河道纵剖面逐渐形成台阶状,与此同时,河口滩地横比降逐渐发展为倒比降;河口河道中段由顺直型... 通过分析黄河口河道在纵剖面、横断面、河型等方面的演变过程,总结归纳出黄河口河道的演变规律。指出:黄河口泥沙在潮汐涨落等因素影响下,河口河道纵剖面逐渐形成台阶状,与此同时,河口滩地横比降逐渐发展为倒比降;河口河道中段由顺直型河道逐渐转为弯曲型河道,而下段仍为相对顺直、游荡型河道。当河口河道中段比降减小到一定程度后,此河段开始漫滩、卡冰、出汊。河口台阶的形成揭示了黄河口流路由单股河道逐渐转为出汊的过程,即黄河口流路由“青壮期”逐渐转为“衰亡期”的过程。延长黄河口流路使用年限的途径是:①尽量减少黄河下游输向黄河口的泥沙量;②采取河口挖沙或人工改汊措施,地点宜选在河口河道的中下段。 展开更多
关键词 黄河口 河道演变 河口台阶 漫滩 出汊 卡冰
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Preliminary Results on Hydrological and Hydrochemical Features of Kartamak Glacier Area in Mt. Muztag Ata 被引量:5
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作者 ZHAO Huabiao YAO Tandong XU Baiqing 《Journal of Mountain Science》 SCIE CSCD 2007年第1期77-85,共9页
The variations of the meltwater runoff draining from Kartamak Glacier in Mt. Muztag Ata in China were studied by using the measured hydrological data from 1 June to 25 August 2003. The meltwater runoff is mainly affec... The variations of the meltwater runoff draining from Kartamak Glacier in Mt. Muztag Ata in China were studied by using the measured hydrological data from 1 June to 25 August 2003. The meltwater runoff is mainly affected by ambient temperature and precipitation. Meltwater and precipitation samples were collected from 10 to 23 August 2003. Their pH, EC (electric conductivity) and the major ions (Na^+, K^+, Ca^(2+), Mg^(2+), Cl^-, NO_3^-, SO_~4^(2-)) were determined. pH values showed a positive correlation with EC values for all samples. Meltwater samples were slightly alkaline. Sulfate and calcium were the dominant anion and cation in the measured ions, respectively. All the ion concentrations had inverse relationships with runoff or water level. In order to discuss the origins of dissolved chemical substances in the glacial meltwater, a principal component analysis was carried out. The results showed that water-rock interaction determined the ion components of the meltwater. 展开更多
关键词 Muztag Ata Kartamak Glacier Meltwater runoff Hydrochemical characteristics
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A New Remote and Automated Control System for the Vineyard Hail Protection Based on ZigBee Sensors, Raspberry-Pi Electronic Card and WiMAX
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作者 Marco Cagnetti Fabio Leccese Daniele Trinca 《Journal of Agricultural Science and Technology(B)》 2013年第12期853-864,共12页
A new inexpensive vineyard protection against hailstorm has been realized and tested. The system has been designed and organized in such a way to perform autonomously local activities to physically control the protect... A new inexpensive vineyard protection against hailstorm has been realized and tested. The system has been designed and organized in such a way to perform autonomously local activities to physically control the protection of the vineyard but also to transmit information toward a remote control. Each row has an "umbrella" designed by the authors which, unlike other commercial solutions, protects the product without hindering all the mechanical activities typical of a modem vineyard. Locally the single umbrella uses an electronic card for the management and a ZigBee mesh telecommunication network to transmit data to a central control unit which manages the protection. Because of its efficiency, a Raspberry-Pi control card has been chosen as central unit. Finally, a WiMAX connection was chosen to remotely control the system, thus allowing the authors to overcome distance limitations of commercial Wi-Fi networks. The system has been realized and tested for some months in field also during a hailstorm. The results of these tests proved how the system is easy to use and effectively protects against hail; moreover the authors proved the high reliability of the mechanical components which allow the authors to lower the maintenance costs. 展开更多
关键词 Anti hail VINEYARD WIMAX ZIGBEE Raspberry-Pi remote control.
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Evaluating the treatment of E-waste──a case study of discarded refrigerators 被引量:1
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作者 DENG Jian-jun WEN Xue-feng ZHAO Yue-min 《Journal of China University of Mining and Technology》 EI 2008年第3期454-458,共5页
Disassembly and recycling of E-waste creates a series of environmental problems. The selection of a technologically reliable, environmentally friendly, economically affordable and socially acceptable recycling technol... Disassembly and recycling of E-waste creates a series of environmental problems. The selection of a technologically reliable, environmentally friendly, economically affordable and socially acceptable recycling technology for E-waste is a significant question. This study establishes a Monte-Carlo mathematical model of cost minimization, given the constraints of environmentally sound handling of the e-waste, in the context of Crystal Ball risk assessment and evaluation software. By following the streams of the different treatment processes, which consist of various technologies including disassembly, recycling and disposal, the econom-ics of various possibilities were identified and the optimal recycling technology proposed. The key factors of the proposed scenarios were determined by using sensitivity analysis. The results of this study show that, for discarded refrigerators, the operating life span plays the key role. The model supports maintenance and resale of the short lived refrigerators. For the longer lived refrigerators material recycling is recommended by the model. Sensitivity analysis shows that purchase cost, plastic sale price, condenser sale price and disassembly costs are the main effects. This study provides a significant technical support for policy making in E-waste management. 展开更多
关键词 E-WASTE end-of-life refrigerator RECYCLING Monte-carlo method sensitivity analysis
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