综合经济目标下的电厂汽轮机组最优负荷分配

提出了基于动态规划法的汽轮发电机组负荷分配的优化模型,该模型考虑了机组主要部件的低周疲劳寿命损耗、机组的最小运行时间和最小停机时间、负荷最大爬升和降负荷速度限制等约束条件,并对各种因素对负荷分配计算结果的影响进行了比较分析.文中以一个具有4台300MW机组的电厂作为运行单元,考虑运行单元内部的各种费用,并将其折合成标准煤耗量.计算结果表明,采用这种负荷分配模型,在满足电网调度负荷的前提下,可以降低煤耗率3g/(kW·h).     

电厂厂级实时监控信息系统(SIS)

电厂厂级实时监控信息系统(SIS)是集过程实时监测、优化控制及生产过程管理为一体的厂级自动化信息系统。SIS系统以机组的性能计算、厂级经济性分析、厂级负荷分配以及机组的经济运行为主要目的,通过对运行状况进行准确的分析、诊断与优化,提高企业自身的竞争力。     

基于EMD距离的燃煤机组煤耗评估分析方法

燃煤机组班组间运行人员操作习惯的差异常常导致煤耗水平存在优劣之分,因此需要对班组进行对标管理,指导班组优化运行方式.传统上一般通过煤耗的均值、极值等统计指标来评估班组能耗水平,但是这些指标不能完整准确地反映班组的运行水平.为此采用了一种基于EMD距离(earth mover’s distance)的燃煤机组煤耗评估分析方法,采用直方图来估计煤耗及其影响参数的数据分布,并用EMD来定量计算数据分布之间的差异,然后以煤耗最低为目标搜索标杆机组,分析导致其他班组与标杆班组煤耗差异的关键参数,为班组运行优化提供建议.这种方法通过对煤耗关键性能指标数据分布的定量分析,实现了对燃煤机组煤耗水平的精准评估,为电力企业降低机组煤耗提供分析手段,也为政府监管部门开展燃煤机组节能降耗精细化对标管理和性能评估提供了技术支撑.     

采用粒子群算法的热电厂热电负荷分配优化

为了优化热电厂内多台机组的热电负荷分配以提高热电厂的经济效益,建立了热电联产机组能耗分析模型和基于粒子群算法的热电厂热电负荷优化分配模型,研究获得了某330 MW热电联产机组的运行区间及运行区间内能量利用效率和■效率的分布规律,进而研究热电负荷分配对热电厂整体能耗特性的影响规律。结果表明:对于单台机组在供热机组的运行区间内,供热量是影响能量利用效率的主要因素,能量利用效率最大、最小值分别为72.11%和34.08%,发电量是影响■效率的主要因素,■效率最大、最小值分别为38.51%和29.97%;通过合理的热电负荷分配,热电厂总煤耗降低,■效率提高。以某热电厂热电负荷边界为例,通过负荷分配优化,热电厂的总煤耗量降低了49.17 t/d,发电标准煤耗率降低了2.56 g/(kW·h)。     

基于发电机组最大调节速率的电网负荷指令调度优化

随着新能源发电的大规模并网,电网平稳运行受到日益严峻的挑战,为充分利用火电等功率可调机组的自动发电控制(automatic generation control,AGC)功能,加快对电网负荷指令的调整,抑制新能源发电波动带来的电网功率偏差,提出一种基于机组最大调节速率的电网负荷指令优化调度方法.首先,对机组实发功率历史数据分段线性表示获得机组调节速率样本,基于调节速率样本分布估计机组最大调节速率,其中采用贝叶斯估计判断样本分布的稳定性;然后,以最短调节时间为目标建立负荷指令调度线性规划模型,求解确定了按机组最大调节速率进行电网负荷调度的策略;最后,通过工业和仿真案例,并与传统负荷分配方法对比,验证了所述方法的有效性.     

葛洲坝水电站厂内优化调度分析

水电站厂内优化调度是一个优化问题,它包括机组组合,负荷分配以及机组检修等问题.针对葛洲坝水电站厂内经济运行要求,在满足电能生产的安全、可靠、优质的前提下,基于动态规划以及遗传算法2种优化方法,对葛洲坝各机组优化调度进行了研究,合理的安排组织电厂设备的运行,以获得尽可能大的经济效益.由计算结果可以看出,运用的2种方法都能较好地求出最优结果,在给定水头和总流量的情况下,合理的进行流量分配,从而实现葛洲坝生产调度的优化运行.     

基于供电煤耗的厂网联合优化节能发电调度

为了尽使全网总损耗降至最小,综合考虑发电机组煤耗及网损,采取联合优化节能调度模型,在电网侧基于等供电煤耗微增率原则,对全网发电机组出力最优分配,综合降低发电煤耗和网损,可有效克服节能发电调度维数灾及收敛难的问题;在电网侧进行出力优化后,电厂侧可基于等煤耗微增率原则,在电厂内部机组进行出力再分配,可克服因通信问题导致的在线煤耗特性误差影响,进一步降低发电机组煤耗,从而达到节能减排的目的。     

供热机组的热电负荷分配

根据供热机组的基本特性，将复杂的供热机组按照供热循环和凝汽循环划分为一定数目的简单等效机组，为了能更准确地描述机组的热力特性，采用考虑辅助汽水系统的单元进水系数法来确定机组的特性方程，然后建立相应的机组热电负荷分配的混合整数线性规划优化模型．实例证明，通过划分等效机组建立的负荷优化调度模型可靠性强，计算时间短，可以实时指导热电厂的最佳经济运行，不需投资仅通过优化调度就可使燃料消耗量约降低1%～3％．     

基于混合粒子群优化算法的机组负荷最优调度

粒子群优化(too)算法是一种现代启发式算法,提出一种基于混合粒子群优化算法的机组负荷的调度方法,该方法考虑了机组的经济性和安全可靠性.优化了机组的调度运行方式.     

黄龙滩电厂机组负荷优化调度的探索

本文通过对水电厂水轮发电机组负荷优化调度分析,探索机组负荷合理分配、科学调度达到最佳经济运行调度方案。     

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.     

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.     

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。     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-