基于遗传算法的火电厂机组间负荷分配的研究

讨论了在火电厂负荷分配中常用的三种方法:等微增率法、动态规划法和遗传算法.采用不同的方法对火电厂机组间的负荷分配进行计算,并对结果进行比较.使用遗传算法来计算火电厂机组间的负荷分配,计算结果简单准确.该算法具有广阔的应用前景.     

自动发电控制(AGC)在小型水力发电厂运行中的应用

根据发电厂与电力系统之间的相互关系,明确了发电厂须依据电力系统分配的负荷进行运行生产。为了实现电厂的经济运行,可采取等微增率法、动态规划法对电力系统给定的生产负荷在发电厂内部进行合理的二次分配,二次分配主要确定机组组合方式、机组启停顺序、各机组出力等,为实现经济运行模式提供基础数据。     

基于成本分析的火电厂日前市场竞价上网报价

针对火电厂在电力市场环境下追求经济效益最大化,优化了机组的负荷分配,掌握企业运行成本,并在电力市场上报出具有竞争力的上网电价。通过分析火电厂各项成本的特点,建立了机组经济性曲线拟合的数学模型和基于序列二次规划法(SQP法)的机组负荷优化分配模型,指出完全成本加成定价法的报价方法,确定火电厂在日前市场的报价模型,并用算例实现了一个火电厂在3个典型时段的报价。     

基于改进动态规划法的火电厂负荷经济调度

提出一种确定火电厂负荷经济调度的改进动态规划方法.先按优先顺序法压缩各时段机组组合状态,再用动态规划法进行计算.新的方法克服了优先顺序法没有考虑启停耗量的不足,也解决了动态规划法的"维数灾"及难于处理的爬坡速度约束问题,且各机组的最优负荷分配与机组的最优启停计划可以同时计算出.     

计及网损的电力系统负荷最优分配中网损微增率的求解

首先介绍了电力系统的发展,在计算网损微增率的过程中,主要使用了潮流计算中收敛后的雅各比矩阵逆阵中的元素求解网损微增率的方法,并通过Matlab程序编制了网损微增率的求解过程,这在实际应用计算负荷分配过程中有着重要的意义。     

火电厂锅炉微油等离子复合点火技术改造浅析

对比分析了火电机组等离子点火、微油点火及复合点火技术的技术特点，结合某大型火电厂机组点火运行中存在的问题，探索微油等离子复合点火技术的可行性及运行方式，经实际运行检验，发现该方法在安全性，稳定性、经济性方面具有明显优势，为火电厂机组安全运行提供技术保障。     

微网中两种典型微型燃气轮机运行特性比较

为给微网中基于微型燃气轮机的冷热电联产设备选型提供参考,从多方面分析了两种不同结构的微型燃气轮机特点,并根据微型燃气轮机不同运行模式切换、不同负荷类型以及不同拓扑结构下的动态特性进行了研究．结果表明：微网运行模式切换过程中,单轴MT允许负荷变化的范围要比分轴MT大;单轴结构MT适用于负荷类型较多情况,而分轴结构的MT则受负荷类型影响相对大些;串联微网结构下MT对应的负荷允许变化范围比并联结构的小．     

发电机组凝汽器背压的优化计算

结合某电厂350 MW发电机组运行数据和凝汽器变工况计算,运用控制变量法分别定性与定量分析了机组负荷、循环水流量、循环水温度对凝汽器背压的影响,并进一步得到这些参数对机组热耗率、机组净功率、全厂供电煤耗率的影响规律。以机组净出力为目标函数,寻找机组运行最佳背压和最佳循环水流量,并给出机组在常用负荷(75%)运行时,循环水泵优化调整方案及优化调整前后全厂供电煤耗率的对比。经优化,循环水泵单泵运行向双泵运行切换的温度点由16℃调整至18℃;通过循环水泵运行方式调整,该台机组全厂平均供电煤耗率可节约0.25 g/(kW·h)。     

某火电厂引风机变频改造节能分析

本文对桌火电厂300MW机组引风机变频改造前后在180MW、200MW、250MW、300MW负荷下的风机机组电能利用率进行了测试计算分析,结果表明该引风机变频改造后风机机组电能利用率由28.5％-51．8％提高至65．1％-75．7％,平均节电率可达42．0％,年节约电量382万kWh,节能效果明显。     

火电厂机组负荷优化调度软件系统的设计与实现

为满足火电厂节能降耗的内在需要,提出了厂级监控信息系统(SIS)平台下的机组负荷实时优化调度软件系统框架,实现了SIS和管理信息系统(M IS)的无缝集成和发电负荷自动分配.通过在线采集运行数据进行经济计算,实时拟合出各机组煤耗特性曲线,建立机组负荷分配的数学模型,在此基础上采用分层模糊遗传算法,实现了机组负荷的最优化调度.基于微软.NET Framework解决方案和Browser/Server多层架构设计思想,设计和实现了该实时优化调度软件系统.采用该软件进行负荷优化调度,可使全厂供电煤耗率比原来的值长制分配模式降低0.5 g/(kW.h)左右,有利于电厂的节能降耗.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.