基于LS-SVM的小水电站年发电量智

针对小水电站年发电量序列的特点，将最小二乘支持向量机（least squares support vector machine, LS-SVM）回归模型引入年发电量预测领域，并给出了相应的过程和算法。与常规基于人工神经网络（artificial neural networks, ANN）的智能预测方法比较，该模型优点是明显的：①将神经网络迭代学习问题转化为直接求解多元线性方程；②整个训练过程中有且仅有一个全局极值点，确定了预测的稳定性。最后，一个实际的预测例子表明：该模型实现容易、预测准确，适用于小水电站预测。     

小水电站年发电量的预测模型及风险分析

通过对小水电站年发电量变化规律及其影响因素的分析,提出了基于小水电站年来水量、年来水量的时空分布及年负荷率等历史统计资料对小水电年发电量进行的线性回归模型,以及对预测结果进行风险分析的方法。最后结合小水电站实例说明了本方法的应用。     

基于NSGA-II算法的硗碛水电站多目标调度研究

为探索硗碛水电站发电与生态效益的矛盾关系,按照不同时间尺度的生态流量下泄方式,建立硗碛水电站年发电量与平均生态流量最大为目标的水库多目标优化调度模型.该模型以MATLAB的platEMO开源工具箱为基础平台,分别运行了基于年尺度与月尺度流量过程的Tennant法生成的生态放水模式,分析了两种模式下发电效益.结果发现:当...     

海乐山水电站的优化设计

海乐山水电站是河北省邯郸市装机容量最大和效益最好的一座引水式电站。1997年2×3.2MW发电机组投产发电,2000年按设计计划续建了800kW小机组,电站装机总容量为7.2MW,设计年发电量19.93GWh。电站投产以来,特别是2000年大小机组联合运行后,产生了良好的经济效益,四年年发电量累计达113.61GWh,平均年发电量为28.4025GWh,是设计年发电量的1.43倍,平均年产值达838.9万元。在我国北方水电站普遍存在实际年发电量难以达到设计发电量的情况下,海乐山电站为什么能连年超额完成设计年发电量?这是因为合理优化设计方案为电站产生良好效益奠定了基…     

基于ESMD-LSSVM模型的径流式水电站出力预测研究

针对径流式水电站日出力随机性强，直接预测精度低的特点，采用极点对称模态分解（ESMD）对出力序列进行平稳化处理，结合最小二乘支持向量机（LSSVM），建立了基于ESMD-LSSVM的组合预测模型。选取西北某省径流式水电站2020年的日出力时间序列进行实例分析，并与单一模型SVM,LSSVM,BP及组合模型ESMD-SVM,ESMD-BP预测效果进行比较。结果发现：(1) PACF分析得到ESMD分解后的各子序列的特征向量不同，反映了径流式水电站日出力的复杂性和多变性的特征。(2)与单一模型相比，组合模型泛化能力更强，对时间序列中出力突变点的预测更准确。(3)ESMD-LSSVM组合模型日出力预测效果较好，为径流式水电站日出力时间序列预测提供了新的方法参考。     

湖南“小水电”战略

全省六十个县主要靠“小水电”供电自1956年南岳华严湖水电站投产后,拉开了全省小水电建设的序幕,全省人民艰苦奋斗,一座座小水电站如璀璨的明珠嵌满三湘西水。据统计,现在全省有98.7％的乡镇和81％村组兴办了小水电,截至1991年止装机总容量达162万kW,居全国第3位,年发电量达43.7亿kWh,1992年前八个月发电量过43亿kWh,有60个县(市)主要靠小     

缙云县小水电的发展前景

目前缙云县已建小水电站141处,总装机容量1.5万千瓦,1984年年发电量5000万千瓦小时(度),预测1988年全县需电量为0.97亿千瓦小时,1990年为1亿千瓦小时,2000年为1.35亿千瓦小时。按分月电力电量平衡及负载、事故备用,全县总装机应达5万千瓦,尚需增建3.5万千瓦,为此必须选择容量较大和技术经济条件较优的方案进行开发。经过一年的勘测和规划,决定采取以下措施:     

九湾溪水电站带侧渠式沉沙池的改进形式

一、概述秭归县九湾溪水电站是迳流式电站。总装机容量4800kW(3×1600kW)。设计水头78.5m,设计流量8.5m~3/s,年发电量3000万 kW·h。水电站建筑物主要有:(1)长97.6m 的底栏栅坝,其中有栅条的坝长40m,栅条间距10mm,安装坡度为10°;(2)长5636m 的输水渠道(含总长3095m 共12条     

波动水资源数据灰幂模型预测中的维数选择

针对GM(1,1)幂模型预测中如何选择合适的样本维数提高模型精度问题,探讨小样本波动统计序列光滑度的判断方法及其对GM(1,1)幂模型预测结果的影响,利用GM(1,1)幂模型白化计算公式完成最小二乘准则下的参数计算,在此基础上构建序列统计数据预测计算模型,将其应用于城市用水量波动统计数据预测,并进行GM(1,1)幂模型样本维数预测精度探讨,计算结果验证了波动统计序列光滑度与GM(1,1)幂模型预测精度的关系,为小样本波动统计序列建模和预测提供了一种计算方法。     

四川小水电有很大发展

四川省已建成小水电站8,258座,装机9,726台,容量为91.3万千瓦,年发电量近23亿度。特别是从1979年以来,发展速度更快,到现在仅三年多的时间,全省共新建小水电站1,670座,装机2,375台,容量35.9万千瓦,相当于1979年前小水电总装机容量59％。     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

车用发动机润滑油失效规律与更换周期研究

研究在正常使用条件下１０Ｗ／３０－ＱＣ级润滑油用于某型车用发动机时所表现的失效规律,确认期服从两参数Ｗｅｉｂｕｌｌ分布,并给出分布的尺度参数η和形状参数ｍ之最佳线性无偏估计（ＢＬＵＥ）同时,还为定量分析,计算车用发动机润滑油的使用可靠性和合理确定其更换周期提供了一套可供借鉴的方法,并给出了具体的计算实例。     

农村剩余劳动力就业问题的探讨

论述了我国农村剩余劳动力就业的意义，并针对我国农村剩余劳动力的现状，提出多渠道促进农村剩余劳动力就业的途径和办法。     

乡（镇）农业技术推广体系存在的问题及对策

乡（镇）农技推广体系是农业发展的关键。介绍朝阳市农业技术推广体系的现状,针对目前体制及运行机制、服务手段等方面存在的问题,提出适合朝阳市乡（镇）农技推广体系改革与发展的对策,以期对全省农技推广体系改革和发展起到一些借鉴作用。     

草莓的采收与贮藏

草莓果味酸甜爽口,营养价值高,为人们所喜爱的应市鲜果之一。由于草莓易受损伤和微生物侵染,因此其采收、贮藏过程极为重要。介绍草莓采收过程中的注意事项以及11种贮藏保鲜技术的实施步骤和操作方法,推介9种加工方式,为草莓产业化提供技术支持。     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。