不同库水模型对高拱坝动力特性的影响

给出了3种模型及不同情况下高拱坝动力特性的数值求解方案,并结合实际工程分析了不同库水模型对高拱坝动力特性所产生的影响.计算和分析结果表明:不同库水模型对坝体的自振频率、振型参与系数和振型等动力特性的影响程度相差较大;可压缩库水模型最能真实地反映库水的特性和库水对坝体动力特性的影响,可采用可压缩库水模型来求解高拱坝的动力特性.     

解非线性方程的一种新的三步六阶迭代格式

Newton迭代法是求解非线性方程的重要方法之一,其收敛阶是二阶,在迭代过程中需要计算一个函数值和一个导数值,因此Newton迭代法的效率指数为1.414 2。基于Newton迭代法结合两步迭代格式构造了一种新的三步迭代格式,通过理论证明其收敛阶是六阶,在迭代过程中每次均需要计算2个函数值和2个导数值,则该三步迭代格式的效率指数为1.565 1,最后数值实验结果也验证了该方法的有效性和可行性。     

基于TDMA的多孔介质热湿耦合模型求解与算法优化

为了提高多孔介质热湿耦合模型的求解效率,采用三对角矩阵求解法(TDMA)对模型进行求解,并将该算法和迭代法进行对比分析.对TDMA计算误差与时间步长之间进行了敏感性分析,基于敏感性分析结果提出了一种变时间步长的TDMA优化算法.数值计算结果表明:对于变物性参数问题,随着时间步长的增加,TDMA计算精度将会下降,而迭代法精度保持不变;对于纤维素绝热材料,当连续2个时间步长内相对湿度变化小于0.24％且温度变化小于0.1℃时,时间步长取值对TDMA计算精度的影响可以忽略;相比于TDMA,变时间步长TDMA算法不受时间步长取值影响,精度更高;相比于迭代法,变时间步长TDMA算法具有相同的计算精度,但用时更短,计算用时可减小67％.     

基于有限差分离散的模方法定价美式债券期权

针对美式债券期权定价模型的数值解法, 构造全隐式的有限差分格式, 并给出格式的稳定性证明. 采用模系矩阵分裂迭代法求解离散得到的线性互补问题, 并与投影超松弛迭代法进行比较. 数值实验验证了新方法的有效性和稳健性.     

基于状态空间理论的工程结构地震时程响应分析

基于状态空间理论分析与计算工程结构地震时程响应问题,根据结构动力学方程,引入结构系统的状态变量,建立结构地震时程响应分析的状态方程,并给出非齐次状态方程的解.为了求解矩阵指数函数,着重介绍了凯莱-哈密尔顿(Kaley-Hamilton)法、状态空间迭代法和精细积分法.对结构动力时程响应问题按这三种解法分别建立了计算格式,并编制相应计算程序.最后,给出若干数值算例,其计算结果表明,状态空间法分析计算结构动力时程响应,其精度好,效率高,是一种非常有效的方法.     

空间结构-地基动力相互作用数值分析时域算法研究

对于大型结构地震响应分析,结构-无限地基耦合系统动力分析的数值实现,往往由于有限元网格过多,以及地基无限域时域计算模型中存在的复杂卷积运算,严重限制了求解规模.为解决此问题,提出了基于阻尼溶剂抽取法的三维结构-地基相互作用分析的分区时域逐步求解模型.并针对三维大规模工程问题的数值求解,在积分算法及矩阵存储格式等方面,结合阻尼溶剂抽取法的特点进行了详细的探讨,以推进动力相互作用时域数值分析的实用化.以三维全空间球形空腔动力变形及大岗山拱坝的地震响应分析为例,针对上述数值实现算法进行了具体验证,并就不同的地基弹模及地震波输入方式对坝体响应的影响进行了探讨.计算结果表明,地基辐射阻尼以及河谷散射效应对结构的动力响应有很大影响,而该模型表现出了良好的精度和计算效率.     

基于投影法的三维流场数值求解方法

本文利用投影法和浸入边界法使用的固定笛卡尔网格技术,三维泊松方程(poisson equation)采用有限七点差分格式离散,结合迭代法和直接法将三维的数值求解问题简化为二维问题,然后利用二维的直接数值解法进行快速的迭代求解.采用VC++编写数值计算代码,通过三维数值算例验证了三维压力Poisson方程求解数值方法的有...     

基于牛顿法的美式期权最优实施边界的数值模拟

美式看跌期权最优实施边界具有单调非减和凸性质,为寻找符合性质的数值解法,本文对非线性最优实施边界问题提出了牛顿迭代格式。通过数值试验分析得出牛顿迭代法下复合梯形格式的图形符合最优实施边界性质,并与不动点迭代法下的复合梯形格式求解的最优实施边界进行了比较,得到两种方法求解的最优实施边界数值解误差非常小。     

一种高效的求解非线性方程的史蒂芬森型迭代法

首先,针对非线性方程求根问题,提出一种最优4阶收敛的无记忆史蒂芬森型方法.在迭代过程中该新方法不需要计算任何导数,仅需计算3个函数值就达到了4阶收敛,该方法的计算效率为1. 587;其次,利用加速参数得到该无记忆迭代法的有记忆迭代格式,进一步提高了收敛阶;最后,将无记忆迭代法扩展到Banach空间,用于求解非线性方程组,并且数值实验结果验证了方法的有效性.     

结构地震反应DQ解法的两种数值格式

通过对时间计算域的离散化将结构地震时程分析问题转化为一系列初值问题的求解,建立了一种基于DQ原理的结构地震反应高精度数值分析方法.为了使DQ原理能够应用于任意变化的地震地面加速度激励下的结构动力分析问题,提出了两种数值方案———单时步格式和多时步格式.单时步格式要求假定时步内地面加速度的分布模式,并且需要对时步进行网格剖分;多时步格式直接利用地面加速度的离散信息构造数值格式,一次运算可获得多个时刻的反应值.数值试验表明:两种数值格式均可以获得较高的数值精度.对于单时步格式,可以通过采用较大步距的方式降低结构动力分析的计算工作量;对于多时步格式,可以通过时步数量的合理选择达到提高计算效率的目的.     

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.     

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.     

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.     

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.     

A computer generator for randomly layered structures

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

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.