斜轧穿孔过程力能参数理论计算研究

由于穿孔机力学性能直接影响无缝钢管的产品质量和品种规格,而目前国内外对斜轧穿孔过程力的特性研究很不充分。为此,针对斜轧穿孔过程中计算力能参数的经验公式
和模拟计算力能参数的有限元方法进行了分析和比较,分析了轧制力、顶头受力和导板受力在整个斜轧穿孔过程中的分布情况,描述了整个斜轧穿孔过程中工件与工具间的受
力状态,给出了力能参数在斜轧穿孔过程中的规律。同时分析了轧制压力计算的经验公式出现误差的原因。结果表明,通过有限元模拟方法可以计算具有较高精确性的力能参数,该方法可应用于工程计算中,为实际生产提供更为准确的轧制力值。     

带钢热连轧过程轧制力有限元模拟

应用DEFORM-2D软件对带钢热连轧过程的轧制力进行了有限元模拟,并与宝钢轧制力模型进行了比较。模拟结果表明,有限元模型计算的轧制力与现场实测数据接近,且计算精度高于宝钢轧制力模型,该模拟对现场轧制工艺参数的调整优化有重要的参考价值。     

锆板轧制模拟的显式动力与隐式静力有限元法比较

针对用作核燃料元件金属包壳的锆合金板建立三维有限元模型,分别运用显式动力与隐式静力有限元法实现了轧制加工的数值模拟.对两种模拟方法下轧制后工件的几何尺寸、接触面上的轧制压力分布等计算结果进行了分析与比较.研究结果表明:通过选取合理的质量放大因子,显式算法的计算效率远高于隐式算法;而隐式静力方法的计算结果比显式动力方法更加平滑;在轧板中部和远离接触表面处,两种方法所得轧制后工件的尺寸吻合得很好;并且两种方法所得稳定轧制阶段的工件表面接触压力分布总体上较为吻合.所做工作可为核燃料元件轧制数值模拟方法的合理选取提供参考.     

铜/铝双金属复合管连轧变形过程数值模拟

本文以铜/铝双金属管的轧制复合为例,对双金属管的连轧变形过程进行数值模拟。铜铝双金属管中铜管为覆层,铝管为基层,轧制工艺采用冷轧复合工艺。轧机采用三辊Y型轧机,结合金属塑性变形理论、管棒材连轧技术、张力减径理论、固体传热模型、刚塑性有限元理论,利用大型非线性显式动力学有限元模拟软件ANSYS/LSDYNA对双金属管的轧制过程进行热力耦合数值模拟分析,对双金属管在轧制复合过程中的塑性变形过程、力学性能、尺寸精度和温度变化分布做了分析研究。     

PC轧机轧制过程轧制力三维有限元模拟

详细介绍了应用ANSYS/LS-DYNA软件建立PC轧机有限元模型求解轧制力的方法,对某1880精轧机组F3机架的轧制过程进行了模拟分析。结果表明,轧制过程等效应力场、等效应变场与实际相符,轧制力模拟值与实测值基本一致,计算结果真实可信,可以为工业生产提供参考。     

Accu-Roll轧管机热轧奥氏体无缝钢管的数值模拟与工艺参数优化

根据钢管斜轧过程的变形特点,利用ANSYS/LS-DYNA有限元软件对Accu-Roll轧管机热轧奥氏体无缝钢管的轧制过程进行有限元数值模拟.通过模拟仿真计算,分析无缝钢管截面的变形特点及轧制力和应力应变分布的变化规律,通过将模拟结果与实测数据进行比较,验证了模型的可靠性.模拟结果表明,在轧制过程中孔型形状不当易造成双鼓形,整个轧制过程中最大轧制应力为403.4 MPa,最大等效应力值为231.8 MPa.     

AZ31B镁板热轧过程的数值模拟

采用Deform-3D有限元软件对AZ31B镁板进行热轧过程数值模拟,对热轧数值模拟过程中镁板的温度分布、裂纹分布、轧制力大小等因素进行分析;并且用Microstructure模块模拟了不同压下量轧制后组织变化情况,为制定合理的热轧工艺提供技术参考。     

基于ANSYS的中厚板轧制前板料温度场数值模拟

温度是轧制过程中的重要参数,采用常规方式难以测得板料内部温度。本文利用有限元软件ANSYS建立了中厚板轧制前板料冷却过程的有限元模型,模型参数化构建,适用范围广。利用模型对一特定尺寸材质为16Mn的板料的冷却过程进行了数值模拟,模拟结果与工程实测结果相符合。     

热连轧粗轧水平辊多道次可逆轧制宽展有限元模拟

利用ANSYS/LS-DYNA有限元分析软件,建立了平轧辊系一体化的三维弹塑性有限元模型;利用小型重启动方法对水平辊多道次连续可逆轧制过程进行了模拟计算,分析了不同轧制规程下轧制出相同厚度中间坯的宽展变化以及不同规格的带钢轧制出不同厚度中间坯的宽展变化.不同轧制规程的模拟结果表明,轧制规程对中间坯的宽度变化关系不大,但是不同的轧制规程消耗的能量不同,所产生的轧制力和轧制力矩也不同.利用小型重启动既可以保证轧制过程的连续性,又可避免模型更新法重复建模的复杂性.     

中厚板多道次热轧过程有限元连续模拟

基于有限元软件Marc,建立了中厚板多道次轧制过程的三维热力耦合弹塑性有限元模拟模型.以等效空心辊替代实心辊,既考虑了轧辊压扁及弯曲变形对其轧件变形的影响,又减少了单元数目并缩短了计算时间,构建了能够将多道次轧制过程连续模拟的有限元输入数据生成系统.通过其网格重划分模块和参数传递模块,使得前一道次的变形与温度的计算结果可用于后一道次模型的初始形状和初始参数,避免了网格畸变引起的计算困难,实现了多道次热轧过程的连续模拟.以某厂实际生产中的7道次连轧参数为例,进行了7道次热轧的连续模拟,所得各道次轧制力及温度结果与实测值吻合,轧辊压扁及轧件厚度分布符合实际规律.     

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.     

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.     

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.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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