用动态有限元法计算加筋板固有频率

采用含有频率变量的形函数代替静态形函数求解结构的振动问题。在Przemieniecki动态有限元概念的基础上,分别构造了Timoshenko梁单元和任意四边形板单元的动态形函数阵并推得其刚度阵和质量法,应用动态有限元法计算加筋板的固有振动频率,结果表明动态有限元法比一般有限元法精度高,更适用于求解结构的动力响应问题。     

非阻塞性颗粒阻尼加筋板振动功率流的研究

针对工程上常用的加筋板结构,推导出了加筋板振动方程,并用拉普拉斯变换法对方程进行了求解,从理论上分析了激励位置、肋骨和非阻塞性颗粒阻尼（NOPD）对板结构振动功率流的影响规律。理论分析和实验研究表明：NOPD能有效地抑制振动能量流的输入及峰值功率流,从而有利于降低板的噪声辐射;当肋骨数目一定时,激励位置靠近加筋板结构的边角、沿矩形板的长度方向加肋和选择比重较大的NOPD,均更有利于减少输入到结构中的能量流。研究结果为该类结构的结构优化设计和阻尼优化配置提供了重要的理论依据。     

正交异性环形板非线性振动的有限元分析

本文用有限元法研究了正交异性环形板非线性振动的频率随振幅的变化规律。由于结构和运动的对称性，三节点九自由度环形单元被采用，计算表明这神单元是高度有效的．系统的动力学方程借助于拉格朗日方程来获得．由于刚度阵中含有非线性项，计算中使用迭代逐步逼近方程的解．与类似方法相比，本文在对非线性刚度阵的线性化方面作了改进，用能量平衡原理求得线性化系数，使计算结果更趋合理．     

加筋夹层板的几何非线性自由振动分析

本文应用能量法与谐波平衡原理求解加筋夹层板的几何非线性自由振动问题。对位移选用多模态近似解析解将连续体进行离散求解.计算了不同边界条件的算例,讨论了加筋(布局、数量、尺寸)对夹层板结果的影响。数值计算表明本文解法非常有效。     

受压加筋板极限承载能力研究

研究了面内单向受压的加筋板单元极限承载能力,考虑了弯扭耦合、加强筋截面变形、板的屈曲以及板和加筋之间的相互作用对加筋板极限承载能力的影响．计算结果表明算法具有较好的精度．     

四边形加筋板的拓扑研究

航天器的结构件为了减轻重量,同时又要确保一定的刚度,往往采用加筋板结构.在重量一定的情况下,筋的拓扑对加筋板的刚度影响很大,因此研究加筋板在不同的约束条件下的拓扑具有重要意义.采用有限元方法,对工程中常用的四边形加筋板进行了研究,得到不同边界条件下,加强筋的合理分布,为工程设计提供了理论依据.     

纯剪切横向密加筋板的加筋弯曲刚度门槛值

针对由横向密加筋板组成的散货船舷侧板承担着较大的面内剪切载荷,而散货船共同结构规范中加筋弯曲刚度设计考虑的是舷外水压力,并没有考虑剪切载荷的问题,研究在剪切载荷作用下横向密加筋板的加筋弯曲刚度门槛值.通过改变加筋的高度,可以改变加筋弯曲刚度,从而使加筋板的剪切屈曲强度和极限强度也随之变化.根据加筋板的纯剪切弹性屈曲强度和极限强度等于材料的剪切屈服极限,找出2种加筋弯曲刚度的门槛值,并把这2种加筋弯曲刚度值与AASHTO规范所得值进行对比分析.结果表明,应由剪切极限强度分析来确定横向密加筋板的无量纲加筋弯曲刚度门槛值.     

基于传递函数的含损伤复合材料加筋板振动

研究了具有基板嵌入分层损伤和筋板脱粘损伤的复合材料加筋层合板的振动特性。根据层合板和层合梁的一阶理论,结合Adams应变能法的模态阻尼模型,建立了含损伤复合材料加筋板动力分析的有限元方法,开发了相应的有限元分析软件。通过典型数值算例的计算结果,分别讨论了具有基板分层和筋、板间脱粘的复合材料加筋板损伤尺度和损伤位置对板的传递函数的影响,得到含不同类型和尺度的含损伤复合材料加筋板的振动特征。     

受压加筋板极限承载能力研究

研究了面内单向受压的加筋板单元极限承载能力,考虑了弯扭耦合,加强筋截面变形,板的屈曲以及板和加筋之间的相互作用对加筋板极限承载能力的影响。计算结果表明算法具有较好的精度。     

非共面加筋结构能量有限元分析研究

为了拓展能量有限元分析在复杂耦合结构振动响应预示中的应用，基于能量有限元理论与能量传递系数计算方法，提出一种针对非共面加筋结构的能量有限元建模分析方法，通过与经典文献中的计算数据进行对比验证方法的合理性，再基于算例分析获取非共面加筋结构在单点简谐激励作用下的能量密度分布规律，并与无加筋的情况进行对比.研究表明：横向激励作用下，结构中的弯曲波能量密度明显高于另外两种面内波，并且加强筋的存在会对面内波的传递起到阻碍作用.     

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.     

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。     

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.     

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.