Environmental flow requirements for integrated water resources allocation in the Yellow River Basin,China

Based on the classification and regionalization of the ecosystem, multiple ecological management objectives and the spatial variability of the environmental flow requirements of the Yellow River Basin were analyzed in this study. The summation rule was used to calculate water consumption requirements and the compatibility rule, i.e., “maximum” principle, was also adopted to estimate the non-consumptive use of water in the river basin. The environmental flow requirements for integrated water resources allocation were determined by identifying the natural and artificial water consumption in the Yellow River Basin. The results indicated that the annual minimum environmental flow requirements amounted to 317.62 × 10⁸ m³, which represented 54.76% of the natural river flows, while for the environmental flow requirements for the integrated water resources allocation were 262.47 × 10⁸ m³, which represented 45.25% of the natural river flows. The highest percentage of environmental flow requirements was 93.64% for the river ecosystem. It can be concluded that the primary concerns should be put on the downstream river water requirements to determine the environmental flows for integrated water resources allocation in a river basin.     

Numerical simulation of discharged waste heat and contaminants into the South Estuary of the Yangtze River

In this paper, a two-dimensional depth-averaged mathematical model based on the finite volume approach is formed, which can be used to compute the flow fields and contaminant movements driven by tidal flows in estuaries with variations in the river bed. The paper also presents a set of appropriate outflow boundary conditions for immersed outlets in water, when these outlets are important to the entire flow region. As an example, the distributions and variations of velocity, temperature, and concentration caused by discharging contaminants from seven sources, two of which are submerged, near the south estuary of the Yangtze river have been simulated over a full tidal cycle. The results of the simulation and prediction are presented, and the effects of the outflow boundary conditions are also discussed.     

The profile of the nozzle of a water cannon designed for maximal inflow velocity

Using the method of total counting, which is based on representing the conditions on the characteristics of the equations of gas dynamics as transfer equations and subsequent approximation of them over triangular grids, we obtain a numerical solution of the variational problem of profiling the nozzle of a water cannon so as to obtain the maximal inflow velocity. We confirm numerically an earlier conclusion reached theoretically that the optimal nozzle of a water cannon contains breaks. Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 24, 1993, pp. 86–89.     

Multi‐area transboundary pollution problems under learning by doing in Yangtze River Delta Region,China

In this paper, we investigate transboundary pollution problems in the Yangtze River Delta Region where emission permits trading and abatement costs under learning by doing. At first, we use the optimal control theory to analyze two‐area transboundary pollution problems and give an empirical study for the Shanghai Municipality and Zhejiang Province by using four‐order Runge‐Kutta method and the authentic economic data. Then, we extend two‐area transboundary pollution problems to three‐area transboundary pollution problems and also give an empirical study by adopting the authentic economic data of Shanghai Municipality, Zhejiang Province, and Jiangsu Province. Finally, we get a similar conclusion that the abatement cost will decrease with the amelioration of abatement technology.     

关于长江水质污染预测的两种数学模型

本文根据《长江年鉴》提供的数据,分别利用灰色系统中的GM(1,1)模型和数值拟合模型,使用mat-lab软件,对长江水质污染问题进行了预测。给出了未来十年内,在不加治理的情况下,长江水质污染状况的数据,并对两种预测模型加以分析和比较。     

最优渡江路线的理论解和非线性规划解

探讨了2003年全国大学生数学建模竞赛D题主要问题的求解,从理论上得出了一个有用的结论,在已知江中各处流速分布的情况下,由该结论可以算出渡江路线的理论最优解.作为对比,文章还建立了非线性规划模型,用LINGO软件求出了近似解.     

长江上游集装箱码头泊位——锚地系统配置策略

针对内河集装箱运输增长与内河航道制约所导致的集装箱运输系统运作效率与航运安全问题,讨论长江上游集装箱码头泊位-锚地系统最优配置策略.通过构建码头泊位-锚地系统的船舶候泊排队服务模型,推导出队长水平状态的稳态概率分布,计算出平均等待队长,并建立泊位-锚地系统配置模型,采用数值算例考察相应的最优配置策略和锚泊溢出概率.     

辽河口附近海冰单轴压缩强度的试验与统计特征

为研究影响海冰单轴压缩强度的因素,在渤海辽河口附近海域采集冰坯,加工成方柱状冰样.在试验温度分别为-3℃,-5℃,-7℃,-10℃和-15℃下,对225个冰样沿平行和垂直自然冰表面方向进行加载.研究试样温度,加载方向,应变速率和孔隙率对海冰单轴压缩强度的影响.试验结果表明:海冰单轴强度随试样温度的降低而增加;垂直方向冰样的峰值强度高于水平方向,海冰表现为各向异性.利用试验结果建立了韧性区内海冰单轴压缩强度与应变速率和孔隙率的统计关系.     

控制点优化磨光算法在长江径流量预测中的应用

盈亏修正磨光法所得到的逼近效果仍然很差,通过控制点的参数优化和目标函数的最小,提出一种控制点优化磨光算法,利用这个算法得到参数后代入模型,使预测的精度得到提高.通过实例,该算法简单易行,并通过相对误差进行了分析,控制点优化磨光算法所得到的预测值好于神经网络模型、PPAR和小波网络模型的预测值,这为研究磨光法提供了较好的分析方法.     

长江经济带经济发展质量的演化趋势与对策研究

在综合已有文献基础上,设计出包含强盛性、有效性、稳定性、协调性、持续性、包容性等六个特性的经济发展质量评价指标体系,并采用主成分分析法对长江经济带11省市1985-2015年的经济发展质量演化趋势进行了测算和分析.主要研究结论:第一,长江经济带11个省市经济发展质量水平与强盛性以及各省市在长江经济带所处地理位置高度一致.第二,有效性和包容性成为长江经济带经济发展质量水平差异的最重要因素,协调性和稳定性的影响程度则呈弱化态势,而持续性的影响表现为一定的波动性.第三,尽管长三角地区经济增长质量水平无论是综合指标还是分项指标均全面领先,但是,长江经济带各省市经济发展质量的差异呈现出缩小态势.为此,提出以下对策性建议:第一,正确认识经济新常态,科学把握新时代转型升级的新机会.第二,准确把握好政府与市场关系.第三,精准定位供给侧改革提升经济发展质量的路径.第四,综合理解包容性增长的现实和战略意义.     

鱼咀及丁坝对长江口航道分流分沙的影响

利用水平二维水流、盐度、泥沙数学模型研究了长江口航道整治工程(一期)实施前后,航道的分水分沙特点,重点讨论了束水丁坝的长度、潜堤的方向对航道分流比、分沙比的影响．数值模拟结果表明,双导堤工程减少了航道的分沙量,这有利于维护航道的畅通,但同时也使航道的分流比减小．航道分流分沙比的改变可通过调整各水工建筑物的布置或尺寸来实现．与束水丁坝长度的影响相比,鱼咀工程潜堤方向的改变对航道分流分沙比的影响更大．     

长三角主要城市空气质量状况与经济社会发展的关联性研究

建立模糊综合模型及面板数据模型对长三角主要城市2006-2013年的空气质量状况进行评价,及对空气质量与主要经济社会因素的关联性进行研究.研究结果表明:长三角主要城市空气质量均在相应的Ⅲ级标准内;经济社会因素的关联程度为:第三产业值对空气质量有正向影响,人口密度、人均生产总值、工业粉尘排放量和第二产业比值这四个指标均对空气质量有负效应.并基于此研究结果进行分析为决策者提供参考,实现长三角地区的可持续发展.     

Vertices, sources and Green correspondents of the simple modules for the large Mathieu groups

We investigate the simple modules for the sporadic simple Mathieu groups M₂₂, M₂₃ and M₂₄ as well as those of the automorphism group, the covering groups and the bicyclic extensions of M₂₂ in characteristics 2 and 3. We determine the vertices and sources as well as the Green correspondents of these simple modules. We also find two 3-blocks with elementary abelian defect groups of order 9 in these groups which are Morita equivalent to their Brauer correspondents.     

基于三阶段SM-DEA-Malmquist指数的长江经济带碳排放效率研究

碳排放问题近年来备受各界学者所关注。为评价长江经济带区域内碳排放绩效,本文结合非期望产出的三阶段SBM-DEA模型和Malmquist指数对2011~2019年长江经济带11省市碳排放效率测算及动静态分析,该模型剔除了环境因素和随机变量的影响,使得测算结果更加符合实际情况。研究表明:长江经济带碳排放绩效呈整体上升态势,且存在东部>中部>西部差异化特征,内部管理对碳排放效率提升的正向作用明显,加大东中西部地区的人才引入及技术交流频度,有助于提升碳排放效率。     

长三角地区能源消费、要素投入与经济增长关系研究——基于变系数和面板因果检验模型

深入研究能源消费及投入要素对经济增长的贡献,对于协调区域要素投入和区域经济的可持续发展具有重要意义.在生产函数框架下,利用1980-2013年长三角地区各省市经济增长与能源消费、要素投入数据,通过控制面板组内自相关、截面相关及组间异方差的变系数模型和面板因果检验模型,研究经济增长与能源消费、投入要素间长期均衡和因果关系.结果表明长三角地区经济增长与能源消费、投入要素间存在长期均衡关系,浙江省的劳动和资本的产出弹性最高,分别为0.515和0.95,江苏省的劳动产出弹性和浙江省的能源消费产出弹性为负,分别为-0.124和-0.338,表现为边际报酬递减特征.长三角地区能源消费和经济增长之间满足反馈假说,并提出提高能源使用效率、调整劳动和能源的投入结构及加大经济转型力度等对策建议.     

System dynamics simulation model for assessing socio-economic impacts of different levels of environmental flow allocation in the Weihe River Basin,China

This study develops a complex system dynamics model (SD) reflecting interactions between water resources, Environmental Flow (EF) and socio-economy using SD software package “Vensim PLE”. The proposed model is employed to assess socio-economic impacts of different levels of EF allocation in the Weihe River Basin of China. Four alternative socio-economic growth patterns and four EF allocation schemes are designed to simulate those impacts. The results reveal that developed SD model performance well in reflecting the dynamic behavior of the system in the current study area. In the meanwhile, an optimal growth pattern considering both socio-economic growth and EF requirements are also found by comparing the different scenario simulation results.     

Modelling and optimization of parallel reservoirs having nonlinear storage curves under critical water conditions for long-term regulation

This paper deals with the problem of parallel reservoirs having nonlinear storage-elevation curves (quadratic functions) for long-term regulation under critical water conditions using the minimum norm formulation. To overcome these nonlinearities, we introduce a set of pseudo-state variables. A set of optimizing equations is obtained. The proposed method is efficient in computing time and in calculating the expected benefits of generation from the system during the critical period. Numerical results are reported for a real system in operation consisting of two rivers; each river has two reservoirs in series.This work was supported by the National Research Council of Canada, Grant No. A4146. The authors would like to acknowledge data obtained from B. C. Hydro.     

A trace theorem for solutions of the wave equation,and the remote determination of acoustic sources

The determination of sources of acoustic wave motion in several dimensions from remote measurements is of considerable interest in many applications, and the underlying mathematical problem is quite ill-posed. We separate the source determination problem into a control problem for the wave equation and an inverse mixed initial-boundary value problem, and concentrate on the latter, in which the initial data for a solution of the wave equation are to be determined from its trace on a time-like hyperplane. Though the geometry of this problem is simple, it exhibits some of the central analytic difficulties of more complex problems. We prove a uniqueness theorem, give examples of instability, establish regularity properties of the trace, and locate noncompact classes of stable functionals. The existence of these noncompact classes shows that the problem is “partially well-posed”, i.e. that smoothing in all directions is not required to regularize the problem, and distinguishes it from most other ill-posed problems, such as backwards diffusion and analytic continuation.     

Simulation of nitrogen contaminant transportation by a compact difference scheme in the downstream Yellow River,China

The rapid agricultural development of the Yellow River basin in China has caused serious potential water pollution to the vicinal areas. In this paper, a compact scheme is developed and employed to simulate the unsteady transportation of three representative water quality variables including ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the downstream Yellow River. As an extension of Ref. [Yang ZF, Chen GQ. The compact fourth-order finite difference scheme for the unsteady convection–diffusion equation involving source term. Chin Sci Bull 1993;38(2):113–6 [in Chinese]], the scheme is applied to the more general convection–diffusion equation with complicated terms reflecting the mutual action of water and sediment, which conforms to the characteristic of high sediment concentration of the Yellow River. The simulation results indicate that the error yielded from the proposed method is smaller than that of the referenced scheme (five-point hybrid scheme) in solving the water quality equation.