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711.
The planning and management of water resources in the Shiyang River basin, China require a tool for assessing the impact of groundwater and stream use on water supply reliabilities and improving many environment‐related problems such as soil desertification induced by recent water‐related human activities. A coupled model, integrating rule‐based lumped surface water model and distributed three‐dimensional groundwater flow model, has been established to investigate surface water and groundwater management scenarios that may be designed to restore the deteriorated ecological environment of the downstream portion of the Shiyang River basin. More than 66% of the water level among 24 observation wells have simulation error less than 1·0 m. The overall trend of the temporal changes of simulated and observed surface runoff at the Caiqi gauging station remains almost the same. The calibration was considered satisfactory. Initial frameworks for water allocation, including agricultural water‐saving projects, water diversion within the basin and inter‐basin water transfer, reducing agricultural irrigation area and surface water use instead of groundwater exploitation at the downstream were figured out that would provide a rational use of water resources throughout the whole basin. Sixteen scenarios were modelled to find out the most appropriate management strategies. The results showed that in the two selected management options, the groundwater budget at the Minqin basin was about 1·4 × 108 m3/a and the ecological environment would be improved significantly, but the deficit existed at the Wuwei basin and the number was about 0·8 × 108 m3/a. Water demand for domestic, industry and urban green area would be met in the next 30 years, but the water shortage for meeting the demand of agricultural water use in the Shiyang River basin was about 2·2 × 108 m3/a. It is suggested that more inter‐basin water transfer should be required to obtain sustainable water resource use in the Shiyang River basin. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
712.
针对2020年第9号台风"美莎克"期间FY-4A 高光谱红外干涉式大气垂直探测仪GIIRS每15 min一次的目标区跟踪加密观测资料,用三维卷积神经网络算法反演的全天空大气温度、湿度廓线分析了台风处于生命史不同阶段时暖心结构和湿度场结构的演变特征。结果表明:卷积神经网络的深度机器学习算法可以用来反演全天空的三维大气温度和湿度垂直廓线,不光适用范围广(晴空和有云视场)、反演精度高,而且反演速度快。利用静止卫星平台高时间分辨率的特性,反演得到的温度、湿度廓线可以细致追踪台风处于发展、成熟和登陆等阶段时暖心结构和湿度场的时空演变特征。台风从发展阶段(热带风暴和强热带风暴)到成熟阶段至登陆消亡时,暖心首先出现在对流层中高层较薄的区域,随着台风强度的加强,深厚的暖心结构明显、强度增加,水平面积增大且垂直往下延伸。由于对流云中强上升气流的输送水汽正距平区逐渐上传至300 hPa,台风最强时密闭云区与四周下沉气流区比湿差高到8 K·kg-1。暖心结构和高湿度中心随着台风登陆而逐渐消失。 相似文献
713.
LIN Bin TANG Juxing TANG Pan SUN Yan QI Jing M. SANTOSH XIE Jinling DENG Shilin LI Faqiao XIE Fuwei ZHOU Aorigele 《《地质学报》英文版》2024,98(1):83-103
Rubidium (Rb) deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites. This study investigates a newly-discovered giant Rb deposit at Gariatong in the Central Lhasa terrane in Tibet. Detailed field studies and logging data revealed that the Rb mineralization mainly occurs in monzogranite and is related to greisenization. LA-ICP-MS U-Pb dating of zircon yielded ages of 19.1 ± 0.2 Ma and
19.0 ± 0.2 Ma for greisenized monzogranite and fresh monzogranite, respectively. The monzogranites are characterized as strongly peraluminous, with high contents of SiO2, Al2O3, K2O and Na2O as well as a high differentiation index. They are enriched in light rare earth and large ion lithophile elements with signi?cant negative Eu anomalies and depleted high field-strength elements. Petrological and geochemical features of these ore-related monzogranites suggest that they are highly fractionated S-type granites, derived from remelting of crustal materials in a post-collisional setting. The geochemistry of zircon and apatite points to a low oxygen fugacity of the ore-related monzogranite during the magma’s evolution. The discovery of the Gariatong Rb deposit suggests that the Central Lhasa terrane may be an important region for rare metal mineralization. 相似文献
714.
Based on Hagget's theory of spatial structure,researches on the nodes and field of tourist origins to Huang-cheng Village in Shanxi Province of China have been explored.Nodal hierarchy structure of tourist origins is analyzed with cluster analysis and the gravity model.And field of tourist origins is analyzed with attraction radius index(R)and geography concentration index(G).In the field analysis,R and G of Huangcheng Village are compared with Xidi Village that is a world heritage located in Huangshan City of Anhui Province in China.According to comparison of loca-tions of two areas,influential factors for field area of Huangcheng Village are identified.It is concluded that:1)cluster analysis and gravity model can be complementary methods to each other for nodal hierarchy structure analysis of tour-ist origins;and 2)as far as location is concerned,the weak intensity effect of tourism resources in the tourist region is a major cause for explaining why tourist origins to Huangcheng Village are mainly its neighboring areas.Moreover,it is suggested that the regional effect of tourist resources should be regarded as a component of destination attractiveness when applying gravity model. 相似文献
715.
716.
We evaluated the effect of ration level(RL) on the growth and energy budget of lenok Brachymystax lenok. Juvenile lenok(initial mean body weight 3.06±0.13 g) were fed for 21 d at five different ration levels: starvation,2%,3%,4% bwd(body weight per day,based on initial mean values),and apparent satiation. Feed consumption,apparent digestibility,and growth were directly measured. Specific growth rates in terms of wet weight,dry weight,protein,and energy increased logarithmically with an increase in ration levels. The relationship between specific growth rate in terms of wet weight(SGRw,%/d) and RL(%) was characterized by a decelerating curve: SGRw=-1.417+3.166ln(RL+1). The apparent digestibility coefficients of energy exhibited a decreasing pattern with increasing ration level,and there was a significant difference among different RLs. Body composition was significantly affected by ration size. The relationship between feed efficiency rate in terms of energy(FERe) and RL was: FERe=-14.167+23.793RL–3.367(RL)2,and the maximum FERe was observed at a 3.53% ration. The maintenance requirement for energy of juvenile lenok was 105.39 k J BW(kg)-0.80/d,the utilization efficiency of DE for growth was 0.496. The energy budget equation at satiation was: 100IE=29.03FE+5.78(ZE+UE)+39.56 HE+25.63 RE,where IE is feed energy,FE is fecal energy,ZE+UE is excretory energy,HE is heat production,and RE is recovered energy. Our results suggest that the most suitable feeding rate for juvenile lenok aquaculture for wet weight growth is 2.89% bwd,whereas for energy growth,the suggested rate is 3.53% bwd at this growth stage. 相似文献
717.
P. textile is an important aquaculture species in China and is mainly distributed in Fujian, Guangdong, and Guangxi Provinces. In this study, an HSP20 c DNA designated Pt HSP20 was cloned from P. textile. The full-length c DNA of Pt HSP20 is 1 090 bp long and contains a 5′ untranslated region(UTR) of 93 bp, a 3′ UTR of 475 bp, and an open reading frame(ORF) of 522 bp. The Pt HSP20 c DNA encodes 173 amino acid residues and has a molecular mass of 20.22 k Da and an isoelectric point of 6.2. Its predicted amino acid sequence shows that Pt HSP20 contains a typical α-crystallin domain(residues 77–171) and three polyadenylation signal-sequences at the C-terminus. According to an amino acid sequence alignment, Pt HSP20 shows moderate homology to other mollusk s HSPs. Pt HSP20 m RNA was present in all of the test tissues including the heart, digestive gland, adductor muscle, gonad, gill, and mantle, with the highest concentration found in the gonad. Under the stress of high temperature, the expression of Pt HSP20 m RNA was down-regulated in all of the tissues except the adductor muscle and gonad. 相似文献
718.
洪水溃坝等复杂灾害现象的时空过程模拟分析,是当前国际地理信息科学热点研究方向之一。随着网络的普及化,公众对GIS时空分析模型的网络实时集成和可视化分析提出了迫切的需求。本文以溃坝洪水为例开展了时空过程网络可视化模拟与分析服务研究,利用Web GL、HTML5、Ajax、Web Service、GPU并行计算等技术手段,通过探讨溃坝洪水时空模型计算优化、网络三维可视化模拟与动态交互分析等关键技术,研发了原型系统并进行应用实验。实验结果表明,本文研究成果有助于实现时空过程信息的网络发布,在线影响分析及动态可视化服务,可为分布式网络环境下溃坝洪水等时空过程信息管理和应急决策提供科学依据和技术支持。 相似文献
719.
针对日常生活中因对温度变化的忽视引起的各种问题,提出一种对温度进行远程监测并短信通知用户的系统,以达到向用户进行温度报警的目的.系统主要由STC89C52单片机,液晶显示器1602,温度传感器DS18B20,TC35模块4大部分构成,首先通过温度传感器DS18B20采集当前环境温度,然后利用液晶显示器1602将当前温度显示出来,与此同时单片机判断当前温度值,当前温度超过温度上限值时,单片机控制GSM模块向指定手机号发送一条短信.结果显示,当温度超过设定温度时,指定手机会收到一条报警短信,提醒用户当前的温度超过了温度上限.通过与传统的温度检测系统作对比,系统能够得到较准确的温度检测值其测温误差能够控制在0.4以下,并且通过发送短信来对温度进行远程实时监测. 相似文献
720.
闫璟 《成都信息工程学院学报》2015,30(2)
在对当前无线网络供求特征分析的基础上,通过研究路由器Openwrt系统的网络架构,对该设计平台下实现无线网络分享的可行性进行探讨.基于Openwrt平台,将无线网络分享及流量平衡的理念引入方案设计中,利用C++语言实现并建立了无线网络流量银行Wlanbank(Wireless LocalArea Networks bank),并对该流量银行的功能和实用性进行了分析.该平台能够方便地实现家庭网络的相互分享,包括客户端与服务器的定时通信、流量结算以及路由器的远程管理等功能.该无线网络分享平台参考金融秩序中的货币流通方式,在流量银行Wlanbank系统中实现在用户互相之间的转账流量交易来获得无线网络的使用,遵循“分享才能使用”、“分享的越多才能使用的越多”的理念,在流量流通过程中制造一种类似金融秩序的平衡,在不损害用户利益的基础上,扩大无线网络覆盖率. 相似文献