啮合双螺杆挤出机的输送与混合特点

论述了啮合型双螺杆挤出机的输送特点;机头压力降与挤出段熔体充满长度之间的关系;分析了双螺杆挤出机螺杆异向旋转和螺杆同向旋转各自的混合性能。及双螺杆挤出机的发展趋向。     

挤出机螺杆的性能评价和设计

挤出机螺杆的作用是使胶料随螺杆旋转运动逐渐变为直线运动,向机头方向推移,并与机身相配合,实现压缩生热、软化搅拌,混合胶料等。文章结合实际,分析了螺杆性能的评价指标等,在此基础上,阐述了挤出机螺杆的设计要领,供大家参考。     

复杂螺杆的参数化设计CAD

双螺杆塑料挤出机中的螺杆较为复杂,螺杆的结构和参数对挤出过程起决定作用.详细分析了螺杆的主要结构形式和螺纹参数的确定方法.以VB为工具研究开发的螺杆参数化设计系统可根据挤出机的用途、产量、原料等使用要求,快速实现双螺杆参数化设计CAD过程,并能方便地根据某些特别要求做出局部调整.     

啮合型双螺杆挤出机的特性研究

在大量实验的基础上,作者指出计量加料对双螺杆的熔体输送有明显影响,故应把计量加料作为啮合型双螺杆挤出机的一个独立操作参量,在国内,作者第一次讨论了类似于单螺杆挤出机的啮合型双螺杆挤出机的螺杆特性线,工作图和工作点,另外作者建议把沿螺杆轴线方向的压力分布作为描写啮合型双螺杆挤出机特性的一个重要参量。     

异型挤出螺杆的数学模型

分析了挤出机的异型螺杆形状特点及螺杆螺旋型面成型方法,建立了几类异型螺杆的数学模型.该数学模型适用于异型螺杆的参数化设计及螺杆数控加工、编程需要。     

螺杆结构对熔融金属挤压成型流场分布的影响研究

基于无限大平板模型进行挤出过程的压力公式推导，开展单螺杆结构对于熔融金属挤出过程的流场分布影响研究。将机头压力损耗计算所得压力数值与单螺杆挤出机建压数值进行对比，从而判断单螺杆挤出机挤出能力。采用ANSYS中的POLYFLOW模块对挤出过程进行仿真模拟，该模块采用网格叠加技术，模拟熔融状态下金属锡的挤出，其中忽略了惯性和重力影响的三维计算，对螺杆进行最优化设计。研究发现减小挤出机的机筒间隙及螺距可以增加螺杆元件对物料的输送能力，且由于金属具有超高流动性，在挤出中并不需要有完整的固体塞段。通过理论分析得到最优螺杆设计参数并完成样机制备，通过实验验证设备的可行性，最终结果表明所设计小型单螺杆挤出机能够实现金属锡的连续均匀挤出。     

螺杆结构对熔融金属挤压成型流场分布的影响研究

基于无限大平板模型进行挤出过程的压力公式推导,开展单螺杆结构对于熔融金属挤出过程的流场分布影响研究。将机头压力损耗计算所得压力数值与单螺杆挤出机建压数值进行对比,从而判断单螺杆挤出机挤出能力。采用ANSYS中的POLYFLOW模块对挤出过程进行仿真模拟,该模块采用网格叠加技术,模拟熔融状态下金属锡的挤出,其中忽略了惯性和重力影响的三维计算,对螺杆进行最优化设计。研究发现减小挤出机的机筒间隙及螺距可以增加螺杆元件对物料的输送能力,且由于金属具有超高流动性,在挤出中并不需要有完整的固体塞段。通过理论分析得到最优螺杆设计参数并完成样机制备,通过实验验证设备的可行性,最终结果表明所设计小型单螺杆挤出机能够实现金属锡的连续均匀挤出。     

螺杆疲劳强度计算

作者从挤出机或注射机螺杆的实际工作状态出发,确定螺杆的工作应力为变应力,分析了目前螺杆设计时所用的静强度计算的缺点,提出了按变应力进行疲劳强度计算的方法,并通过实例对两种计算方法作了比较。     

串联式磨盘螺杆挤出机混合过程的研究

采用网格重叠技术（MST）生成串联式磨盘螺杆挤出机混炼段的有限元网格,对物料在混炼段流场中的动态混合过程进行了模拟,研究了物料粒子的运动轨迹和混合过程;采用流体动力学分析软件POLYFLOW模拟混炼过程,选取停留时间和最大剪切应力作为量化指标,分析和评价了该挤出机混炼段的物料混合性能．研究发现物料在串联式磨盘螺杆挤出机混炼段的停留时间较长,分布范围较广,有利于物料的分散混合和分布混合,得到性能稳定的产品．     

串联式磨盘挤出机提高聚合物复合材料混炼质量的研究

文中阐述了一种新型连续混炼设备——串联式磨盘挤出机的混炼机理 ,采用串联式磨盘挤出机和同向平行双螺杆挤出机对聚苯乙烯/四氧化三铁/丙烯酸、高密度聚乙烯/纳米氢氧化镁进行挤出混炼效果研究 ,通过显微照片和图像分析对共混物微观混炼效果进行数学统计分析 ,发现串联式磨盘挤出机混炼性能明显优于同向平行双螺杆挤出机 ,而且改变其磨盘间隙及螺杆转速可以达到不同的混炼效果。     

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