Study on ES Based Generation System Planning

Based on the analysis of expert experience on generation system planning(GPS), the theory of knowledge based method is introduced into GPS to express the constraints of engineering(viz. Expert experience of engineering), and to discard abundant improper program during the earlier stage of GPS. In this situation, the difficulty degree of optimizing calculation in the later stage of GPS is lessened. And then, integrating expert system with production simulation in a method of GPS is proposed and is verified with an example. The results show that the method presented is effective.     

浅谈“光伏+农业”产业的发展模式

农业在中国经济发展中起着重要作用,是中国社会经济发展的基础。近年来,随着农业机械化以及科技现代化不断推进,多种现代科学技术逐渐在农业产业中得到应用,其中光伏发电技术在农业上的应用对于农业产业转型有着重要意义,是中国农业产业发展的强有力推手。光伏农业是将光伏发电与农业生产相结合的一种绿色、环保的全新产业模式,是集太阳能光伏发电、智能温控系统、现代高科技种植、养殖为一体的农业产业,有着非常广阔的应用前景。本研究综述了光伏农业中主要的几种结合形式：“光伏+种植业”、“光伏+畜禽业”以及“光伏+渔业”的业态,分析了各结合形式的研究现状和面临的问题,并对光伏农业发展趋势进行了合理展望,以期为未来光伏农业的发展提供参考。     

TOPSIS法综合评价宁夏中部干旱带五种风蚀环境抗风蚀性能

针对宁夏中部干旱带土壤风蚀严重、沙尘暴频发等生态问题,分别选择典型压砂农田、沙质旱作传统翻耕农田、人工灌木林地、封育草场和流动沙地5种风蚀环境为研究对象,利用TOPSIS法综合评价不同风蚀环境抗风蚀性能。结果表明:灌木林地的抗风蚀性能最强,其Ci值为0.674257,其次为压砂农田、封育草场;抗风蚀性能最弱的是翻耕农田、流动沙地,Ci值分别为0.087007和0.003552。可见翻耕农田和流动沙地是当地主要沙尘来源。     

中国农村电力普遍服务的理论基础分析

市场化改革之后。通过交叉补贴实现电力普遍服务的机制不可能实施,中国农村电力普遍服务的理论基础值得探讨。农村电力普遍服务是一种特殊的再分配方式,它是缩小地区差距、保证地区均衡发展的重要途径。是实现社会和谐稳定的基础。认为电力产业具有的网络特性、自然垄断性和准公共物品特征,这些因素都可能导致市场失灵,要保证公众所需要的基本生活用电,必然要求建立相应有效的公共政策。     

浅圆仓不同功率风机通风试验研究

利用2.2kW的轴流风机组与7.5kW的离心风机组,对两个浅圆仓进行通风降温,经对比试验,在储粮数量、储粮品种、入仓时间、入仓质量、粮情状况等基本相同的浅圆仓中,当降温效果基本相同时,2.2kW的轴流风机组通风时间较长,7.5kW离心风机组降温效果较快,但水损较多,2.2kW的轴流风机组通风耗能较低,吨粮降温成本较低。     

内蒙古西部地区马铃薯晚疫病菌的交配型分布及对3种杀菌剂的敏感性

研究内蒙古西部马铃薯主产区马铃薯晚疫病菌的交配型组成及对3种常用杀菌剂的敏感性,为生产上防治马铃薯晚疫病提供依据.2008年从内蒙古西部马铃薯主产区分离94个马铃薯晚疫病菌株中,测定其交配型,结果表明,82株为A1交配型,占被测菌株的87.2％;8株为A2交配型,占被测菌株的8.5％;4株为A1A2交配型,占被测菌株的...     

Research on reliability evaluation model for frequency collapse of power grid

In order to comprehensively consider the possibility and the severity of frequency instability risk, this paper proposes the risk evaluation model and algorithm for frequency collapse of power grid. The uncertainties in generating dispatch, network topology and component outage are considered. The calculation method for system frequency variation is depicted while considering the active power deficiency arising from random failure of generating units, and then various probabilistic risk indices for frequency collapse are defined. The presented method can provide important reference information for evaluating the frequency collapse risk of power grid. The non-sequential Monte Carlo simulation-based results of IEEE-RTS79 show the correctness of the method.     

Genetic analyses of agronomic traits in Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.)

The consumption of products made from Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) has increased in recent years in Japan. Increased consumer demand has led to recognition of the need for early varieties of this crop with high and stable yields. In order to accomplish this, more information is needed on the genetic mechanisms affecting earliness and yield. We conducted genetic analysis of 3 agronomic traits (days to flowering, plant height and total seed weight per plant) to segregate F₂ and F₃ populations derived from a cross between Tartary buckwheat cultivars ‘Hokuriku No. 4’ and ‘Ishisoba’. Broad-sense heritability estimates for days to flowering, plant height and total seed weight were 0.70, 0.62 and 0.75, respectively, in F₃ population. Narrow-sense heritability for total seed weight (0.51) was highest, followed by heritability for days to flowering (0.37), with heritability for plant height (0.26) lowest. Later flowering was associated with increased plant height and higher yields. From the F₄ generation, we identified twelve candidate plants with earlier maturity and reduced plant height compared to ‘Hokuriku No. 4’, but almost the same total seed weight. These results suggest that hybridization breeding using the single seed descent (SSD) method is an effective approach for improving agronomic characteristics of Tartary buckwheat.     

生态环境与西部城市竞争力研究

西部城市生态环境的好坏直接关系到西部城市竞争力的培育和提高,而强有力的城市竞争力对加速西部地区城市化进程,促进全国经济均衡持续发展具有重要的战略意义。加强西部城市生态环境建设要注意：坚持可持续发展理念,避免“唯经济发展”观念;加快农村城市化步伐,减轻人口对城市区域环境的压力;大力培育发展环境产业,走生态建市的道路;推行投资项目评估制度,确保西部城市投资项目取得经济效益、生态效益和社会效益的统一;加强生态环境监察执法力度,根除环境污染源。     

Comparative study of low voltage ride-through techniques for doubly-fed induction generator wind turbines under asymmetrical grid faults

Asymmetrical grid faults occur more frequently and have more adverse effects on the doubly fed induction generator (DFIG) than symmetrical grid faults in the transmission system. The transient response of DFIG under asymmetrical grid faults is analyzed firstly. Meanwhile, operation behaviors of several low voltage ride-through (LVRT) techniques under severe asymmetrical grid faults are given by simulation with the Matlab/Simulink software. Then the characteristics of these LVRT techniques are further researched and analyzed based on the simulation results. Finally, the economies of these LVRT techniques are discussed. The conclusion lays a certain foundation for engineering development of these LVRT techniques.