检索结果-南通市图书馆

Application of phase space reconstruction and v-SVR algorithm in predicting displacement of underground engineering surrounding rock

在线全文

学校读者我要写书评

暂无评论

Journal of Coal Science & Engineering(China) 2006年第2期12卷 21-26页

作者：史超陈益峰余志雄杨坤 State Key Laboratory of water Resources and Hydropower Engineering Sciences Wuhan UniversityWuhan 430072China Guangzhou Guangyuan Construction company Guangzhou 510010China

A new method for predicting the trend of displacement evolution of surroundingrock was presented in this *** to the nonlinear characteristics of displace-ment time series of underground engineering surrounding rock,based on phase spacereconstruction theory and the powerful nonlinear mapping ability of support vector ma-chines,the information offered by the time series datum sets was fully exploited and thenon-linearity of the displacement evolution system of surrounding rock was well *** example suggests that the methods based on phase space reconstruction and modi-fied v-SVR algorithm are very accurate,and the study can help to build the displacementforecast system to analyze the stability of underground engineering surrounding rock.

关键词： displacement of surrounding rock phase space reconstruction support vector machine prediction

Multi-objective interval prediction of wind power based on conditional copula function

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2019年第4期7卷 802-812页

作者： Gang ZHANG Zhixuan LI Kaoshe ZHANG Lei ZHANG Xia HUA Yongqing WANG Institute of water Resources and Hydro-Electric Engineering Xi’an University of TechnologyXi’an 710048China State Grid Shaanxi Baoji Electric Power company Baoji 721000China State Grid Gansu Electric Power company Gansu Electric Power Research InstituteLanzhou 730050China State Grid Shaanxi Electric Power company Shaanxi Electric Power Research InstituteXi’an 710054China

Interval prediction of wind power,which features the upper and lower limits of wind power at a given confidence level,plays a significant role in accurate prediction and stability of the power grid integrated with wind ***,the conventional methods of interval prediction are commonly based on a hypothetic probability distribution function,which neglects the correlations among various variables,leading to the decrease of prediction ***,we improve the multi-objective interval prediction based on the conditional copula function,through which we can fully utilize the correlations among variables to improve prediction accuracy without an assumed probability distribution *** use the multi-objective optimization method of nondominated sorting genetic algorithm-II(NSGA-II)to obtain the optimal solution *** particular best solution is weighted by the prediction interval average width(PIAW)and prediction interval coverage probability(PICP)to pick the optimized solution in practical ***,we apply the proposed method to three wind power plants in different cities in China as examples forvalidation and obtain higher prediction accuracy compared with other methods,i.e.,relevance vector machine(RVM),artificial neural network(ANN),and particle swarm optimization kernel extreme learning machine(PSO-KELM).These results demonstrate the superiority and practicability of this method in interval prediction of wind power.

关键词： Wind power prediction Interval prediction Conditional copula function Empirical distribution function Multi-objective optimization algorithm

Cationic content effects of biodegradable amphoteric chitosan-based flocculants on the flocculation properties

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2012年第8期24卷 1378-1385页

作者： Zhen Yang Yabo Shang Xin Huang Yichun Chen Yaobo Lu Aimin Chen Yuxiang Jiang Wei Gu Xiaozhi Qian Hu Yang Rongshi Cheng State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentSchool of Chemistry&Chemical EngineeringNanjing UniversityNanjing 210093China Zhenjiang water Supply company Zhenjiang 212009China

A series of biodegradable amphoteric chitosan-based flocculants （3-chloro-2-hydroxypropyl trimethyl ammonium chloride （CTA） modified carboxymethyl chitosan, denoted as CMC-CTA） with different substitution degrees of CTA were prepared successfully. The content of carboxymethyl groups in each CMC-CTA sample was kept almost constant. The solubility of the various flocculants showed that, higher cationic content of flocculants caused a better solubility. The flocculation experiments using kaolin suspension as synthetic water at the laboratory scale indicated that the substitution degree of CTA was one of the key factors for the flocculation properties. With the increase of cationic content, the flocculants were demonstrated better flocculation performance and lower dosage requirement. Flocculation kinetics model of particles collisions combining zeta potential and turbidity measurements was employed to investigate the effects of the cationic content of the flocculants on the flocculation properties from the viewpoint of flocculation mechanism in detail. Furthermore, flocculation performance using raw water from Zhenjiang part of Yangtze River at the pilot scale showed the similar effects to those at the laboratory scale.

关键词： amphoteric chitosan-based flocculants substitution degree of CTA flocculation kinetics and mechanism

Hydrological cycle research by D&^(18)O tracing in small watershed in the loess hilly region

在线全文

学校读者我要写书评

暂无评论

International Soil and water Conservation Research 2013年第3期1卷 75-82页

作者： Xu Xuexuan Zhao Jiaona Zhang Xiaoni Institute of soil and water conservation Northwest A&F UniversityXi'anShaanxiChina Xiangyu water Conservancy Survey and Design Limited company XingtaiHebeiChina Institute of soil and water conservation Northwest A&F UniversityShaanxiChina

The objective of this study was to determine the mechanisms of the hydrologic cycle in the loess area in *** eight water samples from precipitation,soil water of the 0-4 m layer,surface water in the valley,ground water(spring and well)were collected and the Deuterium(D)and Oxygen-18(^(18)O)of these water samples were analyzed to interpret the relationship among those waters in the watershed in the loess hilly region during *** results show that:the D&^(18)O of precipitation in Yangou was consistent with that of Xi,an,apparently the north migration of water vapor in Xi^an;according to the correlations among the differential waters in D&^(18)O,confirmed that precipitation recharge could account for most of the sources of valley flow,with part of the recharge water going to soil water *** D&^(18)O of groundwater were very close to that of precipitation,likely the soil preferential flow was dominant in groundwater recharge although the infiltration had a certain *** the influence of rainfall and evaporation,the response of the soil moisture profile,and its D&^(18)O profile were *** soil moisture had the strong influenced layer in the 60-160 cm range,a weak impacted layer in 60 l60 cm,and a stable layer below l60 *** was shown that the soil evaporation depth could be up to l60 cm because the D&^(18)O changed in that *** study could increase our understanding of the magnitude and pattern of the hydrologic cycle,which should improve water resources management in the watershed scale.

关键词： Hilly area in the Loess Plateau Precipitation Groundwater Soil water D&^(18)O

Wind power prediction based on variational mode decomposition multi-frequency combinations

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2019年第2期7卷 281-288页

作者： Gang ZHANG Hongchi LIU Jiangbin ZHANG Ye YAN Lei ZHANG Chen WU Xia HUA Yongqing WANG Institute of water Resources and Hydro-Electric Engineering Xi’an University of TechnologyXi’an 710048China State Grid Gansu Electric Power company Gansu Electric Power Research InstituteLanzhou 730050China State Grid Shaanxi Electric Power company Shaanxi Electric Power Research InstituteXi’an 710054China

Because of the uncertainty and randomness of wind speed, wind power has characteristics such as nonlinearity and multiple frequencies. Accurate prediction of wind power is one effective means of improving wind power integration. Because the traditional single model cannot fully characterize the fluctuating characteristics of wind power, scholars have attempted to build other prediction models based on empirical mode decomposition(EMD) or ensemble empirical mode decomposition(EEMD) to tackle this problem. However, the prediction accuracy of these models is affected by modal aliasing and illusive components. Aimed at these defects, this paper proposes a multi-frequency combination prediction model based on variational mode decomposition(VMD). We use a back propagation neural network(BPNN),autoregressive moving average(ARMA)model, and least square support vector machine(LS-SVM) to predict high, intermediate,and low frequency components,respectively. Based on the predicted values of each component, the BPNN is applied to combine them into a final wind power prediction ***,the prediction performance of the single prediction models(ARMA,BPNN and LS-SVM)and the decomposition prediction models(EMD and EEMD) are used to compare with the proposed VMD model according to the evaluation indices such as average absolute error, mean square error,and root mean square error to validate its feasibility and accuracy. The results show that the prediction accuracy of the proposed VMD model is higher.

关键词： Wind power prediction Variational mode decomposition Multi-frequency combination prediction Back propagation neural network Autoregressive moving average model Least square support vector machine

Full-scale application and performance of a new multi-self-reflow decentralized Wastewater treatment device: Impact of hydraulic and pollutant loads

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2023年第9期131卷 37-47页

作者： Xiang Li Yong Huang Yi Guo Wei Li Yuqing Li School of Environmental Science and Engineering Suzhou University of Science and TechnologySuzhou 215009China Jiangsu Collaborative Innovation Center of Technology and Material of water Treatment Suzhou University of Science and TechnologySuzhou 215009China Suzhou SuJing Environmental Engineering company Jiangsu Suzhou Purification Group Technology CompanySuzhou 215009China

Decentralized treatment of wastewater in rural areas usually has several challenges,which include large fluctuations in pollutant concentration and water quantity,complicated operation and maintenance of conventional biochemical treatment equipment,resulting in poor stability and a low compliance rate of the wastewater treatment *** order to solve the above problems,a new integration reactor is designed,which uses gravity and aeration tail gas self-reflux technology to realize the reflux of sludge and the nitrification liquid,*** feasibility and operation characteristics of its application for decentralized wastewater treatment in rural areas are *** results demonstrated that,under constant influent,the device showed strong tolerance to the shock of pollutant *** chemical oxygen demand,NH_(4)^(+)-N,total nitrogen and total phosphorus fluctuated in the ranges of 95–715 mg/L,7.6–38.5 mg/L,9.32–40.3 mg/L and 0.84–4.9 mg/L,*** corresponding effluent compliance rates were 82.1%,92.8%,96.4%and 96.3%,*** the wastewater discharge was non-constant and the maximum single-day Qmax/Qmin reached 5,all indicators of the effluent met the relevant discharge *** integrated device also demonstrated high phosphorus enrichment levels in its anaerobic zone;the concentration of phosphorus reached a maximum of 26.9 mg/L,which created a good environment for phosphorus *** microbial community analysis showed that sludge digestion,denitrification,and phosphorus-accumulating bacteria all played an important role in pollutant treatment.

关键词： Decentralized wastewater treatment Integrated device Self-reflux technology Load shock Operational characteristics

Intelligent Speed Limit System for Safe Expressway Driving in Rainy and Foggy Weather Based on Internet of Things

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2023年第1期28卷 10-19页

作者：燕北瑞方成邱昊朱文峰 School of Mechanical Engineering Tongji UniversityShanghai 201804China Zhejiang Highway&water Transportation Engineering Consulting Limited Liability company Hangzhou 310006China

The feature bends and tunnels of mountainous expressways are often affected by bad weather,specif-ically rain and fog,which significantly threaten expressway safety and traffic *** order to solve this problem,a vehicle–road coordination system based on the Internet of Things(IoT)is developed that can share vehicle–road information in real time,expand the environmental perception range of vehicles,and realize vehicle–road *** helps improve traffic safety and ***,a vehicle–road cooperative driving assistance system model is introduced in this study,and it is based on IoT for improving the driving safety of mountainous *** the influence of rain and fog on driving safety,the interaction between rainfall,water film,and adhesion coefficient is *** intelligent vehicle–road coordination assistance system is constructed that takes in information on weather,road parameters,and vehicle status,and takes the stopping sight distance model as well as rollover and sideslip model as boundary *** conducted on a real expressway demonstrated that the assistance system model is helpful in bad weather *** system could promote intelligent development of mountainous expressways.

关键词： rainy and foggy weather expressway driving assistance system Internet of Things(IoT)

Infuences of Different Admixtures on the Drying Shrinkage Characteristics of Metakaolin-based Geopolymer Mortar

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2024年第6期39卷 1425-1433页

作者： ZHI Jing ZHANG Chengyang WANG Yunwen WEI Libao ZHANG Pan State Grid Gansu Electric Power company Wuwei Power Supply company Wuwei 733000China State Grid Gansu Electric Power company Baiyin Power Supply company Baiyin 730900China

To investigate the influences of different admixtures on the drying shrinkage of polymer mortar in a metakaolin base,the experiments of VAE(vinyl acetate ethylene copolymer),APAM(anionic polyacrylamide)and CPAM(cationic polyacrylamide)on the drying shrinkage properties of geopolymer mortar were designed under normal temperature curing *** SP-175 mortar shrinkage dilatometer was introduced to measure the dry shrinkage of geopolymer ***,the drying shrinkage properties of geopolymer mortar are exhibited by the parameters of water loss rate,drying shrinkage rate,drying shrinkage strain and drying shrinkage *** experimental data are further fitted to obtain the prediction model of dry shrinkage of geopolymer mortar,which can better reflect the relationship between dry shrinkage rate and ***,the experimental results demonstrate that the dry shrinkage of geopolymer mortar can be significantly increased by adding 4%VAE admixture,meanwhile under the condition that the polymer film formed by VAE reaction can strengthen and toughen the mortar.2.5%APAM admixture and 1.5%CPAM admixture can enhance the dry shrinkage performance of geopolymer mortar in a certain range.

关键词： metakaolin base polymer mortar dry shrinkage property admixture dry shrinkage prediction model

The Technology and Economic Analysis of the DCC and MIP Processes at Anqing Petrochemical company

在线全文

学校读者我要写书评

暂无评论

China Petroleum Processing & Petrochemical Technology 2006年第3期8卷 7-13页

作者： Li Jibing SINOPEC Anqing Branch company Anqing 246001

In order to meet the demand for gasoline quality upgrading, SINOPEC Anqing Branch Com- pany has retrofitted the DCC unit with the MGD technology and equipped the FCC unit with the MIP technology. This article makes an analysis and comparison on commercial application of the MIP and the DCC/MGD processes in terms of technology and economics while focusing on their specific features and methods for maximization of their economic benefits.

关键词： MIP DCC/MGD process economics economic benefit