牵切过程中纤维长度指标的控制

合理配置牵切工艺参数是控制牵切条中纤维长度指标(平均长度、长度不匀、短纤维率)的关键,这是纺制高品质牵切纱的前提.通过对牵切区中纤维运动和断裂规律进行分析,明确了牵切隔距、牵切倍数、纤维断裂点分布是影响牵切条纤维长度指标的主要牵切工艺参数,并确定了它们之间的定量关系,其中牵切隔距影响最大.研究结果为牵切生产实践提供了理论参考依据.     

苎麻罗拉梳麻机梳理作用分析

本文对苎麻罗拉梳麻机的喂给机构与梳理质量的关系进行了讨论.对纤维喂入负荷、锡林与工作罗拉的速比、隔距和梳理质量的关系亦进行了分析.得出如下结论:1.喂给机构梳理作用对梳理质量有明显影响.喂给机构的梳理度应在0.3—0.9针/每根纤维,速比在20—30为宜.2.在锡林与工作罗拉梳理部份,影响梳理质量的主要因素是纤维喂入负荷,而锡林与工作罗拉的速比、隔距对梳理质量无明显影响.     

毛条产品质量的研究与控制分析

腈纶丝束采用拉断工艺方法制条。本文分析腈纶丝束本身质量对拉断纤维长度的影响。创新生产工艺，适当调整拉断机再割区的隔距和牵伸倍数，可确保纤维平均长度波动偏差缩小，从而提高产品质量。     

喷射FRP拉伸力学性能的试验与分析

为研究喷射FRP的拉伸力学性能,文中对13组试件进行了单向拉伸力学性能试验,分析其应力—应变曲线、抗拉强度、拉伸弹性模量、断裂伸长率等力学性能指标。研究纤维类型、树脂种类、纤维体积率、纤维长度、试件厚度等因素对喷射FRP力学性能的影响。结果显示:纤维类型和树脂种类对喷射FRP拉伸力学性能的影响十分明显;纤维体积率为20%~25%,纤维长度为40 mm时,喷射FRP能获得较好的力学性能;喷射FRP试件厚度增加并不能持续有效的增强力学性能,不宜过厚。研究表明:为获得较好的力学性能,喷射FRP宜采用碳纤维喷射纱和乙烯基酯树脂加工制作,纤维体积率和长度宜控制在一定范围,且材料厚度不宜过厚。     

牵伸区浮游纤维变速的数学建模与仿真

有效地控制须条在牵伸区内滓游纤维的运动，使其变速点分布更为合理，尽可能降低条干不匀率，是牵伸理论研究的基本问题。而对于纤维的运动大部分研究工作除实验分析外，也有一些学者在理论上对变速点的分布和变细曲线的关系作过讨论，但对于变速点的分布形式，尤其是在压力棒牵伸形式下的分布，只作了桌些定性的解释。这里在总结前人经验的基础上，通过对牵伸区浮游纤维的受力分析，建立了纤维变速的数学模型，并结合计算机技术，通过计算机模拟的方法，作了在多种条件下的变速点分布仿真，从得到的直方图和变速点分布的统计结果中，可以看出在牵伸区中的浮游纤维其变速点分布虽是随机的，但由于工艺参数的影响，呈一定的正偏态或负偏态分布，并进一步分析了摩擦力界、纤维长度、罗拉隔距、牵伸比等多种因素时变速点分布规律的影响。     

罗布麻纤维氧化还原体系脱胶预处理工艺

预处理是脱胶工艺的重要环节,为了进一步提高罗布麻的脱胶效果与制备纤维的可纺性能,对其脱胶预处理工艺进行研究.试验在罗布麻纤维的脱胶预处理过程中,逐次加入还原剂硫脲,氧化剂双氧水两种组分,讨论了2组分浓度配比、预处理温度、时间对胶质去除的影响,分析预处理前后纤维纵向形貌的变化,同时还测试了氧化还原预处理脱胶工艺对制备罗布麻纤维性能指标的影响.结果表明采用该氧化还原预处理脱胶工艺可提高罗布麻纤维的脱胶制取率、纤维长度、单纤维强力等性能指标,是一种有效的脱胶预处理方法.     

羊毛束纤维蒸汽处理后的拉伸性能研究

探讨羊毛柬纤维经蒸汽处理后拉伸性能的变化。在INSTRON上对处理时间不同的羊毛柬纤维，采取不同的夹持隔距进行拉伸试验，结果表明，在一定条件下，随着处理时间的增加，柬纤维强力下降，断裂伸长增加，其拉伸力学性能随隔距增大的变化趋势与未经蒸汽处理的柬纤维基本一样：断裂强力逐渐下降，断裂伸长，断裂功逐渐增大。     

拉断工艺纤维长度控制的研究

腈纶丝束采用拉断工艺制条,分析了腈纶丝束本身质量对拉断纤维长度的影响。创新生产工艺,适当调整拉断机再割区的隔距和牵伸倍数,可使纤维长度分布符合要求,波动偏差小,从而提高产品质量。     

PVA纤维表面覆油量对SHCC拉伸性能的影响

为了制备高强高韧应变硬化水泥基复合材料(SHCC),并且研究PVA(聚乙烯醇)纤维对其受拉特性的影响,使用不同PVA纤维配制SHCC并进行单轴拉伸试验,分析PVA纤维覆油量、纤维长度对其强度与韧性的影响,采用傅里叶转换红外线光谱(FTIR)和扫描电子显微镜(SEM)观测纤维属性,用超景深显微镜统计裂纹数目并计算其平均宽度.结果表明:采用不同覆油量的PVA纤维均能制备SHCC;当覆油量为0.8%、纤维长度为12mm时,配制的SHCC特性更佳;采用不同覆油量的PVA纤维配制的SHCC在断口处残留纤维长度不同.     

秋葵纤维的化学脱胶工艺

采用化学脱胶处理秋葵纤维,对预酸和碱煮工艺中的参数进行优化设计,提取出可纺纤维,并对处理后纤维的长度、细度及断裂强度进行测试和评价.预酸处理,硫酸溶液质量浓度2 g/L,处理时间120min,处理温度60℃.浴比1:15;碱处理,一煮碱溶液质量浓度7.5 g/L.二煮碱溶液质量浓度9 g/L,一煮处理时间3.5 h.二煮处理时间2 h,处理温度100℃.浴比1:20.其中一煮与二煮中添加2%的硅酸钠、尿索和JFC.纤维性能测试结果表明:残胶率为7.32%,工艺纤维长度为10～30 cm、细度为2.8 tcx,断裂强度为23.8 cN/tcx.     

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.     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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