发电商多交易策略的有效前沿分析:（一）模型的建立

电力系统和电力市场特殊的技术性约束和结构性约束，使得电力市场中发电商的策略组合可行集与资本市场中投资者的策略组合可行集存在显著差异，而现有的研究对这些差异没有进行系统的探讨，这给发电商多交易策略研究成果应用于实际的发电商决策造成了困难。文中针对目前研究存在的不足，以有效前沿为分析工具，着重探讨电力系统和电力市场的技术性约束和结构性约束对发电商多交易策略可行集的影响，得到了发电商多交易策略有效前沿的形状不同于一般投资市场有效前沿的结论。从理论上阐明了发电商多交易决策中考虑电力市场特殊约束的重要性。     

基于CVaR风险计量指标的发电商投标组合策略及模型

电力市场中各类市场具有不同的价格波动特性和收益率随机变化特性。为了保证年度收益最大且风险最低，发电商需在各个市场上合理分配参与竞价的电量。借鉴金融领域风险管理的理论，以条件风险价值（CVaR）为风险计量指标，综合考虑风险和期望收益率，建立了新的发电商均值-CVaR投标组合优化模型。应用该模型，对发电商在年度合约市场、月度合约市场、日前市场和实时市场4个市场总电量的分配比例和有效前沿进行了计算。计算结果表明，所提出的模型能较真实地反映发电商所面临的市场风险的本质特征，可使发电商在保证一定期望收益率的前提下承担最小的CVaR风险，从而为发电商的投标决策与风险评估提供了新的思路。     

不确定市场下的一种二层规划最优竞价模型

在不确定的电力现货市场条件下，讨论了发电商和售电商关于长期合约交易与现货交易之间的最佳选择策略方法，提出一种(随机)二层规划理论模型及其求解算法。根据求解结果，发电商可确定适当的合约电价及合约电量，使公司获得最大利润；售电商能对签订多少合约电量和购买多少现货电量做出最佳决策，使公司获得最大效益。最后给出了结论及需进一步研究的问题。     

考虑输电约束的期权市场与现货市场联合均衡分析

针对实际运营电力市场的需求，研究发电商在期权市场与现货市场的联合竞争问题，建立了一个考虑输电约束的两阶段古诺博弈模型。该模型是一个具有均衡约束的2层数学模型，可使用非线性互补方法和改进的Levenberg-Marquardt算法求解。结果表明，输电阻塞抑制了发电商参与期权交易的积极性，削弱了期权对电力市场的作用，加强了处于阻塞有利位置的发电商的市场力，发电商可通过策略性竞标剥夺用户和网络所有者的部分或全部收益。     

发电商资产组合研究

发电商在电力市场中的整个决策过程可分为3个阶段：投资决策、资产组合和策略选择。资产组合与投资决策和策略选择一样，是整个发电商效用最大化问题的重要一环。文中基于证券投资领域近年来的研究成果，提出了一种方法，根据该方法对电力市场重新建模，并对该方法的可信性和有效性进行了全面的验证和考察。为了使结果更有可信度，算例采用实际电力市场（PJM）的真实电价数据。算例和拓展计算的结果反映了该资产组合方法的可信性和有效性，且不同的资产组合会使发电商的收益和风险产生很大的差别。     

基于企业经营决策的发电商最优竞价策略

在电力市场环境下，发电商的策略性投标行为关系到电价风险、市场稳定、市场力滥用行为及发电商自身利润等诸多问题。文中在对发电机组成本/需求的微观经济分析基础上，建立了机组面对需求曲线的公式及求解方法，提出了机组市场价格控制区的新概念。基于经济学中企业经营决策的最大利润原理，阐述了“边际发电成本等于边际发电收入”的机组最优竞价准则，提出了拥有不同市场力的发电商最优竞价策略及算法。     

需求侧参与期权市场的电力市场均衡分析

期权是电力市场参与者使用的主要金融工具之一。建立了风险厌恶的购电商以效用最大为目标、风险中立的发电商按Cournot方式竞争的两阶段博弈模型，给出了市场均衡的解析解。结果表明期权对电力市场的作用要强于远期合约，随着购电商等值风险规避指数和现货市场电价波动性的增加，发电商的市场力逐渐加强，为保持较高的收益和现货市场电价，发电商有兴趣维持现货市场电价的高波动性。     

基于Hotbooting-Q算法的抽水蓄能电网电能交易风险识别方法

为提升电网电能交易收益以及风险识别精准度,提出了基于Hotbooting-Q算法的抽水蓄能电网电能交易风险识别方法.搭建了基于深度Q学习算法的电网电能交易博弈模型,并运用Hotbooting技术求解模型Q值表及V值表,获取最佳交易策略;同时构建了抽水蓄能电网电能交易风险识别模型,将获取的最佳交易策略输入模型,分别求解交...     

考虑多时间尺度的梯级水电站组合交易风险自适应感知方法

为了控制交易风险发生概率，规避交易风险，助力收益最大化，提出考虑多时间尺度的梯级水电站组合交易风险自适应感知方法。综合考虑多时间尺度，将梯级水电站交易方式划分为上下两层，各层利用多时间尺度的马尔科夫决策描述梯级水电站的交易过程，搭建梯级水电站组合交易序贯模型，并采用人工蜂群算法求解获取组合交易最佳策略，搭建基于条件在险价值的组合交易风险度量模型，给定置信水平，求解组合交易最佳策略的风险值，实现梯级水电站组合交易风险自适应感知。实验结果表明，所提方法能够选取最佳组合交易决策，决策后的水电出力可满足实际负荷需求，拥有理想的决策性能；能够感知各时间段内组合交易的风险值，且应用该方法后可有效控制交易风险发生概率，应用效果极佳。     

分组竞价的电力合约市场交易模式

合约市场是电力市场的重要组成部分，它通过中长期合约交易降低发电商的市场风险，保证电力系统长期安全平稳运营。文中紧密结合我国现状，充分考虑各发电公司由于历史原因造成的在市场上竞争能力的差异，提出了分组竞价的概念和交易机制，在最大限度上保证各发电公司的公正和公平性。提出了分组竞价的合约市场交易模型和算法，可以同时考虑上升、下降及混合型报价曲线。算例分析表明，这种分组竞价机制能保证交易的经济性和公平性，将对电力市场的稳定运营提供有力的保障。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.     

Serial discontinuities in a Rocky mountain river. II. Distribution and abundance of trichoptera

River regulation in the headwaters and middle reaches of the Gunnison River, Colorado, significantly altered distributions and abundances of Trichoptera fauna. Twenty-five species were collected from mainstream samples, with the greatest species richness occurring at an unregulated, rhithron segment above the central reach dams. At sites immediately below the three hypolimnial-release dams and a reregulation dam, species richness was reduced 35–90 per cent and abundance > 95 per cent. Net-spinning caddisflies were the dominant trichopterans at unregulated sites; Arctopsyche grandis in the upper reaches (218 organisms, 586 mg dry mass m^?2) and Hydropsyche cockerelli, H. occidentalis and Cheumatopsyche pettiti in the lower river (9041 total organisms, 6621 mg m^?2), downstream from the last dam. The observed distributional pattern of low trichopteran densities in dam tailwaters and high hydropsychid densities at sites 60–80 km below the central reach dams is a classic expression of continuum resets and adjustments in response to stream regulation as predicted by the Serial Discontinuity Concept.     

Surveying for Water Resources

Abstract

A professional Land Surveyor (Geomatician) describes the Hydrogeologists' survey requirements of a major water resources assessment for the government of The Sultanate of Oman (1992 to 1996). The need for objective specifications is stated. Specialist terms like geoid, spheroid, Mean Sea Level are explained and how to relate spheroidal levels to the geoid. Methods like traditional survey, satellite survey, and photogrammetry are introduced. The paper encourages coordinated working for the benefit of water resource assessment and recommends employment of the professional land surveyor for major studies.     

The Impact of Economic Development on Water Pollution: Trends and Policy Actions in Malaysia

The paper examines the impact of development activities on water pollution in Malaysia. Hence, the main objective of this paper is not just to examine the trends of development-induced water pollution around the region of the country but to know where the problems are and the policy measures taken by the government. It evaluates the probable causative relationship between problems introduced due to technology employed in water pollution control and governmental policy measures. It examines the relationship between development indicators as sources of pollution and polluted rivers over a period of 12 years. The findings of the paper have shown that despite the policy enforcement actions against the identified sources of water pollution, all the three development indicators (chosen based on those identified sources) still accounted for high percentage of river pollution in Malaysia. The findings of the paper were used to identify the central fact of the location of the problem. Some crucial conclusions of where the problems likely to be, as reflected in the findings, are: (a) the issue of interactive-effects between pollutants that many policy-makers are not aware of. This is when policy measures concentrate only on one source of water pollution; (b) the enforcement strength and/or effectiveness of policy measures themselves; (c) financial constraints to invest in appropriate technology especially sewerage systems for controlling human source of water pollution in the country; as well as those confronting small polluting industries (d) finally, lack of cooperation between government and private business firms to comply with regulatory policies for water pollution control.     

浅淡溢洪道改扩建方案与选择

溢洪道改扩建和进行溢洪道方案布置，要择优选取溢洪道进口型式、防冲消能工，以使其工程量省、施工快、运行管理方便     

Intangible Flood Damage Quantification

Flooding is a natural disaster that may cause tremendous tangibleand intangible damage to the national economy. The tangible damage assessment, i.e. the monetary value of all direct and indirect physical damages, has already been studied, whileintangible damages have not yet been taken into account. Thisarticle, therefore, is the first systematic attempt to assess bothtangible and intangible damages. The new proposed Anxiety-Productivity and Income Interrelationgship Approach (API) has been developed to quantify the intangible damage in monetary terms. The Bangkok area has been selected as the research area because several severe flood events have occurredthere over the last two decades. The 1983 Bangkok flood caused 6600 million baht in damage, according to estimates by the National Statistical Office (NSO). This article examines the totalflood damage (including the intangible damage) at different flood magnitudes. Case studies with and without flood mitigation projects are studied and compared. Furthermore, thisarticle also discusses the improvements over the conventional approach offered by the new API methodology.     

Seasonal variation in nutrient retention during inundation of a short‐hydroperiod floodplain

Floodplains are generally considered to be important locations for nutrient retention or inorganic‐to‐organic nutrient conversions in riverine ecosystems. However, little is known about nutrient processing in short‐hydroperiod floodplains or seasonal variation in floodplain nutrient retention. Therefore, we quantified the net uptake, release or transformation of nitrogen (N), phosphorus (P) and suspended sediment species during brief periods (1–2 days) of overbank flooding through a 250‐m floodplain flowpath on the fourth‐order Mattawoman Creek, Maryland U.S.A. Sampling occurred during a winter, two spring and a summer flood in this largely forested watershed with low nutrient and sediment loading. Concentrations of NO increased significantly in surface water flowing over the floodplain in three of the four floods, suggesting the floodplain was a source of NO. The upper portion of the floodplain flowpath consistently exported NH, most likely due to the hyporheic flushing of floodplain soil NH, which was then likely nitrified to NO in floodwaters. The floodplain was a sink for particulate organic P (POP) during two floods and particulate organic N and inorganic suspended sediment (ISS) during one flood. Large releases of all dissolved inorganic N and P species occurred following a snowmelt and subsequent cold winter flood. Although there was little consistency in most patterns of nutrient processing among the different floods, this floodplain, characterized by brief inundation, low residence time and low nutrient loading, behaved oppositely from the conceptual model for most floodplains in that it generally exported inorganic nutrients and imported organic nutrients. Published in 2007 by John Wiley & Sons, Ltd.     

Experience in the Introduction of Steam-Water-Oxygen Cleaning, Passivation, and Preservation at the TÉTs-23 Cogeneration Plant of the Mosénergo Company

Conditions of the process of steam-water-oxygen cleaning, passivation, and conservation (SWOC, P, and C) of internal heating surfaces of the boiler and the high-pressure feed heater (HPFH) piping over the steam side are presented. The process produces partial cleaning of the internal heating surfaces from scale and yields a corrosion-resistant protective film that hinders corrosion processes both in the operation of the boiler and in the idle period.     

钢筋混凝土三点弯曲梁断裂韧度计算模型

基于虚拟裂缝模型,针对钢筋混凝土试件在三点弯曲作用下开裂截面的受力特征,在合理假定的前提下,给出了一种计算钢筋混凝土三点弯曲梁的失稳断裂韧度的解析方法。然后,应用该方法计算了初始缝高比 α₀（初始裂缝长度与试件高度的比值）分别为0.2,0.3,0.4,0.5的三点弯曲试件的最大荷载和临界有效裂缝长度,进而求得了钢筋混凝土三点弯曲梁的失稳断裂韧度。通过对计算结果与试验数据的误差分析,发现失稳断裂韧度最大误差为4.915%,说明这种方法可以较为准确地预测三点弯曲梁的失稳断裂韧度。在此基础上研究了初始缝高比 α₀对失稳断裂韧度的影响,发现失稳断裂韧度基本上不随 α₀ 变化,失稳断裂韧度可以作为材料常数,应用于裂缝扩展状态的判断。