粗旦丙纶强力丝的生产初探

介绍了粗旦丙纶强力丝的生产工艺、着色方法及存在的问题。认为聚丙烯切片的分子量、分子量分布以及纺丝、拉伸工艺的合理调整等是丙纶强力丝生产中的关键。     

卧式一步法丙纶高强丝生产工艺研究

在意大利ＦＡＲＥ公司卧式一步法丙纶高强丝设备上，研究了聚丙烯熔融指数与丙纶高强丝强度的关系。探讨了纺丝温度、冷却条件、单丝纤度、拉伸倍数等主要工艺条件对丙纶高强丝强度的影响。     

二步法丙纶高强工业丝纺丝工艺研究

通过试验和生产实践,研究了二步法丙纶高强工业丝的纺丝工艺条件、原料和产品性能之间的关系,为工业化生产的最佳工艺选择提供了参考依据。     

丙纶细旦长丝的研制

介绍了丙纶细旦长丝的生产工艺。在国产纺丝设备 KP431丙纶纺丝机上,采用高熔融指数树脂,喷油上油、适当调整侧吹风温度和风速、以及牵伸机卷绕张力,生产出了单丝纤度为2.31—2.36dtex,强力为4.3—4.4cN/dtex 的丙纶细旦丝。     

意大利FARE公司丙纶高强丝设备及工艺

介绍了意大利ＦＡＲＥ公司丙纶高强丝设备，并对其工艺及技术特点进行了分析。     

聚丙烯短纤维工业生产的新技术

综述国外聚丙烯纤维的生产和应用情况,重点介绍意大利ZETA公司最新无螺杆短程纺短纤维的设备和工艺,其中包括熔融纺丝和后加工装置、工艺流程、原料单耗及公用工程;还介绍了英国PFE公司丙纶短纤维生产的由下向上喷丝的纺丝新技术。     

丙纶粗旦纺丝生产工艺探讨

着重丙纶粗旦丝纺丝工艺参数与切片ＭＩ值，冷却条件和喷丝板孔径之间的关系，为企业生产选择最佳纺丝工艺参数提供参考。     

丙纶高强丝的生产及应用

本文概述了丙纶及丙纶高强丝在国内外的发展概况、高强丝的性能及开发应用情况，介绍了丙纶高强线的一步法和两步法生产工艺和设备，并就纺丝温度、纺丝速度、冷却在形、拉伸温度、拉伸倍数、拉伸速度等工艺参数进行论述。     

一步法生产丙纶工业丝的工艺探讨

研究了用一步法生产丙纶工业丝的纺丝温度、冷却成形条件、拉伸温度、拉伸倍数等工艺参数对生产过程的影响,并将产品质量指标与国外同类产品进行了比较.     

装饰用阻燃丙纶短纤维通过鉴定

装饰用阻燃丙纶短纤维通过鉴定丹阳合成纤维厂开发的阻燃丙纶装饰用短纤维产品，于１９９５年１０月６日在丹阳通过省级鉴定。该厂利用引进德国巴马格公司制造的短程纺设备，优选了阻燃剂及关键技术工艺参数，开发生产出阻燃丙纶装饰用短纤维产品，具有工艺流程短，生产效...     

基体种类对CTBN改性环氧树脂结构和性能的影响

研究了ＣＴＢＮ对不同种类的环氧树脂（Ｅ－５１、Ｆ－５１）力学性能的影响,通过扫描电镜观察了２种增韧体系的微观结构形态,并探讨了２种增韧体系的微观结构形态与力学性能间的关系。     

筛孔塔板气液两相流动的速度场模拟

<正>由于气体的搅动,筛孔塔板上的流动是极其复杂的气液两相流。目前两相流理论尚不成熟,未见运用此理论对塔板流速场的研究报道,Zhang和Yu的研究虽考虑了气相对液相流动的影响,但由于利用单相流理论,计算结果与实际情况有较大偏差。本文利用Elghobashi等建立的两相流双流体模型,建立了塔板上气液两相流二维流速场计算模型。在此基础上,通过调整模型参数,考虑了液层高度对塔板上返流区二维流型的影响,建立了模型参数值与液层高度的关系,实现了考虑液层高度影响的二维流动——拟三维流动的模拟。计算结果与Porter的实验结果基本相符。     

Bimodal crystalline orientation in polypropylene: Mechanism of formation

Melt-spun polypropylene fibers have two sets of crystallites, each with a different preferred orientation. A probable kinetic mechanism of nucleation and growth of the two sets of crystallites, based on an analysis of crystallization in oriented polymers, is proposed. Experimental data on the fractions of these two sets of crystallites in as-spun fibers and the effect of subsequent drawing or thermal annealing on the relative amounts of these two sets are presented.     

蓖麻油聚氨酯基网状聚合物的动态力学性质

研究了蓖麻油聚氨酯基AB型交联聚合物(ABCP)及同步法合成互穿聚合物网络(IPN)的动态力学谱。ABCP的两组分近似互容,在动态力学谱上呈现出单一T_g松弛,用透射电子显微镜观察,聚氨酯相区尺寸小于 2 nm;而其化学组成相同的 IPN则呈现出两相结构,其动态力学谱上有两个 T_g松弛,两组分间虽有链段互穿,但其相容性仍次于 ABCP。     

The adhesional electrification force between randomly rough surfaces with identical materials

Abstract

I present a general theory for the adhesional electrification and find a necessary force to separate two identical rough plates. This theory is a continuation of the previous research. In addition to the effect of the fluctuations of charge density, the roughness effects of two identical plates are considered. When both surfaces are rough but uncorrelated results an increase in the electroadhesion force in comparison to the case of only one rough surface. The roughness leads to an increase in the area of the rough surfaces as well as the magnitude of the positive and negative charges on the surfaces and this leads effectively to a larger charge induction. Therefore, the electroadhesion force increases between two rough plates by growing the magnitude of charges on the surfaces. When there is a cross correlation between two surfaces, the perturbed force is different from the case where there is no cross correlation between two surfaces for the constant charge density. As a result, if the cross correlation between two surfaces is positive (negative), the perturbed force is smaller (larger) than the case of two uncorrelated rough surfaces.     

Statistics of Brittle Failure in Multiaxial Stress States

Two methods for relating failure statistics for different stress states in brittle materials are compared. Despite the fact that the two methods are based on the same fundamental assumptions on crack distributions, they give apparently very different formulations. In this paper it is shown that the two methods are equivalent, and the apparent ambiguity resulting from having two seemingly different results from the same set of basic assumptions is removed.     

Evaluation of the relation between the compressive strength of cement by the British Standard cube test and iso-rilem prism test

The compressive strength of cement mortar is principally determined by two methods, either by cubes or by prisms. In the cube method, the compressive strength is evaluated by directly subjecting the cube specimens to compressive load, where as in the prism method, the standard mortar prism (4×4×16cm) is first broken to two halves by flexural test, and then each half prism is subjected to compressive stress by distributing the axial compressive stress on the specified area on the two plane faces. This paper, aims at finding the relation between the compressive strength of the same cement, by these two methods of test.     

SETTLING VELOCITIES OF TWO EQUAL-SIZED SPHERES FOLLOWING EACH OTHER IN VISCOUS FLUIDS CONTAINED IN CYLINDERS

Experimental data are presented for two equal-sized spheres falling along the axis of a cylinder. The two spheres settle with the same velocity as that of a single falling sphere as long as their separation distance is larger than a critical value. When the distance is smaller than the critical value, the two spheres fall faster than a single sphere. The drag on the two spheres is less affected when two spheres fall in a cylinder in comparison to the situation when two spheres fall in an unbounded medium. The data are correlated and shown to agree with numerical calculations.     

Nanostructures at Electrostatic Bond Interfaces

During electrostatic bonding of aluminum to Pyrex glass, γ-Al₂O₃ is formed on the interface between the two materials in two distinct morphologies. The first, and more obvious, morphology is that of highly textured nanocrystalline structures growing from the interface into the glass. These nanostructures have a distinct effect on the width of the sodium-depletion layer formed in the glass and are associated with precipitates in the aluminum adjacent to the aluminum/Pyrex interface. The second morphology of γ-Al₂O₃ is an anodic oxide layer on the interface between the two materials. Together, these two morphologies enable strong bonds to be made.     

Elastic characterization of CVD diamond by static and dynamic measurements

The present paper describes two different nondestructive approaches for the direct identification of the elastic constants of thin square isotropic plates. First a static method is presented, by which the identification of the Young's modulus and Poisson's ratio is carried out by the full field measurement of the out-of-plane displacements detected on the upper surface of the plate in two biaxial bending tests. Then a dynamic method is illustrated, by which the elastic constants are determined from two different natural frequency of a free vibrating plate. Both techniques, previously verified on a carbon steel specimen, have been applied to a CVD diamond specimen; a comparison between the two approach is reported and the influence of the measurement errors is also discussed.