明渠渠底糙率突变对紊流边界层影响的试验研究

利用激光测速仪,对壁面糙率突变时的明渠紊流进行了试验研究,测量了糙率突变不同水深情况下明渠紊流的纵向时均流速和脉动流速。通过实测资料分析水深和糙率改变后内边界层发展变化规律、粗糙度和水深对内边界层的厚度的影响以及糙率突变后从一种均匀流到形成新的充分发展的紊流所需要的纵向长度。     

关于《厂房顶溢流的原型观测》一文中紊流边界层问题的商榷

[日本]三井一郎与秋秀一在第十届国际大坝会议上所发表的“厂房顶溢流的原型观测”一文①系统阐述了为鉴定在[日本]中部地区建成的新成羽大坝(高为103米的混凝土重力拱坝)的坝后溢流厂房在洪水期的安全所进行的现场观测试验及其成果的分析研究;为今后在高山峡谷河段建造高水头、大容量水力发电枢纽工程提供了宝贵经验。由于溢流面的各种水力特性都与紊流边界层的发展有关,论文提出了一个用数值积分法解紊流边界层的方法。计算所得的边界层厚度δ值与实测值比较获得了相当一致的结果。但笔者发现论文中边界层排挤厚度δ~*、动量厚度θ及流速分布参数H等均有错误;从而其计算结果与实测值比较所     

U形渠道直壁槽式量水堰的流量系数和流速系数的探讨与计算

本文通过理论分析,推导了U形渠道直壁槽式量水堰的流量系数和流速系数的理论计算式,讨论了流量系数的变化规律。并在大量试验研究的基础上,得出了上游水头与水深、上游水头与喉道临界水深的线性关系,提出了流量系数和流速系数的实用计算公式。     

铸铁中第三组元的偏析参数

本文从schiel方程推导出在给定冷却速度下铸铁枝晶奥氏体及共晶奥氏体中第三组元的偏析参数KS和偏析梯度KR的计算式,并讨论了计算值与实测值之间的差别。     

溢流反弧段的壁面摩阻特性的分析与计算

本文将流速对数律和流速指数律相联系,推导了溢流反弧段的摩阻流速的计算公式,对其进行了分析。并利用所量测的反弧段流速指数和边界层的资料,计算了不同粗糙度和不同曲率半径时反弧壁面摩阻流速及切应力等。     

两相流理论在挟沙水流流速分布和阻力求解中的应用

利用紊流条件下的固液两相流基本方程,结合推移质运动水流的概化模式,推导出定床和动床两种情况下明渠带推移质水流的流速分布和阻力系数公式。通过实测资料的计算,证明了理论分析的合理性。     

在园弧曲面上急流的扩散

本文对园弧曲面上急流的扩散进行了研讨,根据驻波理论推导出波角计算式;水流转向与水深变化的关系式;特征线方程.据此对园弧曲面上急流的扩散进行了求解.     

长幅摆线针齿行星传动的运动分析

本文依据长幅摆线针齿行星传动的工作原理,分析了针轮针齿与摆线轮轮齿啮合的运动关系,推导出了轮齿间相对运动速度以及齿廓滑动系数的计算式;并作了数值计算和分析。     

溢流反弧段紊流边界层变化规律的数值模拟

在溢流反弧段流线同心圆假定的基础上,通过理论推导,建立了表征反弧段动水压强、壁面势流流速、壁面切应力的相应表达式;将描述边界层发展变化规律的连续方程、动量积分方程、动能积分方程联立,并运用列主元高斯消去法将其转化为一阶微分方程组,采用双边法求其数值解,从而模拟出反弧段水深、边界层厚度以及流速分布指数的沿程变化规律。     

平衡盘灵敏度的定义与计算

本文第一次定义了节段式多级离心泵平衡盘的灵敏度,建立了计算式,并依据现有资料给出灵敏度的合理范围。     

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.     

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.     

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.     

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…