河道汇流演算方法对比分析与研究

分别采用分段马斯京根法、反映河道断面形状和水力特性的变动参数Muskingum-Cunge(MC)演算法和Muskingum-Cunge-Todini(MCT)可变参数法对沅水流域沅陵站—王家河站河段进行河道汇流演算,探讨了具有分布式参数的演算方法在实际河道的应用效果。结果表明,分段马斯京根法、MC演算法、MCT可变参数法均较好地模拟出洪水在河道的推移与坦化,模拟精度较高,且MC演算法和MCT可变参数法的确定性系数相对分段马斯京根法精度更高且更为稳定;MC演算法和MCT可变参数法对分段马斯京根法参数特性进行了较好的改进,并且MCT可变参数法解决了MC演算法蓄量和稳态不一致的问题。总体上看,3种方法对于洪水预报具有较强的适应性和可靠性,为实时洪水预报提供了新方法。     

河段汇流参数抗差估计研究

当河段实测出流流量值被不服从正态分布的异常值污染时,最小二乘法不能获得参数最优估计.为此,采用崩溃率为20%、附有条件的抗差最小二乘法估计马斯京根汇流参数最优值.通过对闽江永安河段理想模型参数的计算,比较了参数抗差最小二乘法与最小二乘法抵抗2类误差的效果.结果表明,抗差最小二乘法能排除异常值对参数估计的影响而获得稳健性的参数.     

小流域洪水预报新安江模型参数优选方法及应用研究

针对小流域洪水降雨强度大、历时短、汇流速度快的特点,提出了一种应用新安江模型进行小流域洪水预报及模型参数优化率定的方法.该方法以最小二乘法作为模型参数优选的准则,并采用逐次渐进网格寻优法优选模型参数.由于该方法同时优选所有模型参数,不需要对实测径流进行分割,从而可避免人工分割径流而出现的参数率定误差.最后,按照该方法,应用二水源、三水源新安江模型对广东省黄京塘流域进行了研究计算,优选出了模型参数.模型验证结果表明,二水源新安江模型效果比三水源新安江模型好.     

河道洪水演算的径向基函数神经网络模型

将径向基函数神经网络方法应用于河道洪水演算中，并利用最小二乘法来确定模型参数。结合河道洪水演算的具体方式，分别构建基于马斯京根方法和具有预见期的洪水演算方法的径向基函数神经网络模型。将该模型应用于两条天然河道的洪水演算中，计算结果表明，该模型运算快速，精度较高，具有较大的应用价值。     

马斯京根法——河道洪水演算的线性有限差解

常用的马斯京根法,是河道洪水演算的线性有限差解,它的入流条件应当是三角形的,选取时段长的条件应当是△t=K,在长河段的情况下,应当用分段连续演算。这一个计算系统,比较简便而且合理,宜于在实际中应用。如入流条件为矩形,也可以用有限差求解,其结果与纳须模型S-曲线解所得的十分相近.马斯京根法的积分解必然导致负效应,不宜应用,应用其特解纳须模型完全就可以了。但它提供了矩法,有意义。     

河道洪水演算方法在淮河及滹沱河中游的应用

为解决马斯京根法在河道洪水演算中未考虑河道断面特征和水力特性的变化问题,在淮河中游吴家渡至小柳巷河段、滹沱河中游黄壁庄至北中山河段采用考虑河道断面几何形状和水力学糙率的Muskingum-Cunge-Todini可变参数法和非线性水库法进行河道洪水演算研究,探讨考虑河道断面特征和水力特性的演算方法在湿润区淮河中游及半干旱区滹沱河中游的适用性,并将模拟结果与马斯京根法进行比较。结果表明,Muskingum-Cunge-Todini可变参数法和非线性水库法在研究河道上模拟精度较高,洪峰合格率均在86%以上,确定性系数均大于0.8,可应用于河道洪水预报。     

扩散波与马斯京根法在栅格汇流演算中的应用比较

以数字高程模型(DEM)为基础,对分布式水文模型中的汇流演算方法进行研究。以皖南山区呈村流域为例,分别采用扩散波模型与马斯京根法进行栅格单元间的汇流过程模拟,对2种汇流演算方法进行应用比较。结果表明,采用2种方法模拟的洪水过程精度基本相当,均能取得较好的应用效果。通过进一步对比分析后发现,两者在描述参数与变量的空间分布、运算效率等方面存在一定的差异。     

基于遗传算法的TOPMODEL参数优化

模型参数的确定是模型研制与应用成功与否的关键.一般采用人工经验率定和自动率定两种方法来确定.遗传算法和一般的优化算法不同,它具有全局寻优能力,是一类优秀的非线性函数优化算法.利用遗传算法来进行TOPMODEL参数优化,并和人工率定的计算结果作了简要的对比,明显地显示该方法的优点.采用遗传算法所得到的精度较高,可以类推到其他水文模型的参数优化中去.     

淮河上中游复杂流域洪水预报

为了提高淮河洪水预报的精确度,以鲁台子和鲁蚌区间作为研究区域,选取2000—2017年之间的13场洪水资料,在降雨径流方面采用新安江三水源模型进行模拟预报,分别将鲁台子以上和鲁蚌区间分为9个和4个自然子流域,进行参数率定;对具有行蓄洪区的淮河干流河段进行节点概化,结合分流比法和马斯京根法,建立了具有行蓄洪区流域的洪水预报模拟方法,取得较好的模拟预报效果。研究结果表明:在洪量相对误差方面,鲁台子和鲁蚌区间的预报合格率都达到100%;在洪峰相对误差方面,鲁台子流域的合格率达到100%,而鲁蚌区间则达到92. 3%。2003年和2007年这2场大洪水的洪峰相对误差和确定性系数方面都得到显著改善。     

基于遗传模拟退火法的马斯京根方程参数估计

提出一种用遗传退火算法估计马斯京根方程参数的新方法，在遗传算法中融入模拟退火算法，在每一代群体产生后，对各个个体独立地进行模拟退火过程，以其结果再作为下一代群体的个体，避免了简单遗传算法容易提前收敛的缺陷以及模拟退火法搜索较盲目的缺点，应用实例表明方法简便，直观，可广泛应用于解决多种模型的优化问题，特别在洪水预报方面有很好的应用前景。     

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.     

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.     

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.     

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.     

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.     

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that