柔性石墨的生产和发展

本文论述了柔性石墨的生产工艺和应用特点,尤其是其重要原料可膨胀石墨的几种生产工艺比较,并对柔性石墨的国内外发展作了展望。     

膨胀石墨低温物理机械性能测试研究

简介了新型密封材料膨胀石墨即柔性石墨的主要特点，给出膨胀石墨的低温力学性能和热学性能测试数据，并对测试结果进行了分析讨论。     

柔性石墨——一个新产业的发展与展望

本文对柔性石墨新产业的概况及柔性石墨的工艺、性能进行了综述介绍,并对技术发展的方向、新产业的发展前景进行了讨论.     

我国柔性石墨密封材料的现状与发展趋势

本文对我国近年来应用的新型柔性石墨密封材料的现状,质量、市场及发展趋势等问题提出见解,企望抛砖引玉,在行业中求得共识,以利完成密封材料在我国的更新换代工作,并使新型柔性石墨密封材料工业能较快地发展,获得更高的经济效益和更好的社会效益。     

柔性石墨双极板透气性的研究

由于柔性石墨材料具有耐腐蚀特性 ,与电极、电解质不发生作用 ,并具有重量轻、厚度小、导电、导热性能好的优点 ,是制造质子交换膜燃料电池双极板理想的材料。由于燃料电池双极板还要求严格的阻气性能 ,本文通过对柔性石墨制造双极板的研究 ,提出了相对透气系数的概念以表征柔性石墨材料的阻气性能。并利用自行组装的测试设备研究了柔性石墨板密度、厚度以及空气压力差对相对透气系数的影响。研究结果证明柔性石墨材料具有很小的相对透气系数 ,并且阻气性能稳定。     

柔性石墨——金属间腐蚀问题的研究现状与分析

目前，国内外减缓柔性石墨－金属间腐蚀的研究主要包括柔性石墨中其他物质的添加及柔性石墨中残存硫的降低等两方面的工作。本文对近年来这一工作的主要进展进行了简要的回顾与分析，并在此基础上对柔性石墨－金属间腐蚀问题研究工作的进一步开展提供出了一些看法或建议。     

柔性石墨板材开发——引进设备与中科煤—Ⅱ型的技术经济浅析

本文简要叙述了柔性石墨产品的主要用途，研究分析了我国引进日本、美国板材生产线技术特点，并与我国研究开发的中科煤—Ⅱ型生产工艺、产品质量进行了对比。通过简略的技术经济分析，结合我国国情，阐述了加大我国柔性石墨研究开发力度的重要意义。     

理想柔性石墨抗拉强度的计算机模拟

依据柔性石墨强度的物理模型和已知的石墨性能与结构参数,同时考虑到压轧过程中回弹率和微晶取向角的变化,利用有关的摩擦学知识,探讨对理想柔性石墨抗拉强度进行计算机模拟,最终计算求得柔性石墨的理论抗拉强度,进而比较了计算结果与实验结果,讨论了模型的适用范围。     

纤维增强柔性石墨—橡胶密封材料的制备及性能研究

制备了几种柔性石墨—橡胶复合密封材料，研究了纤维、柔性石墨含量等对材料性能的影响，结果表明纤维增强柔性石墨—橡胶密封材料具有较好的综合性能，是一种新型的有发展前途的无石棉密封材料。     

燃料电池流场板新材料的研究

在不同工艺条件下将石墨蠕虫用压片机压制成柔性石墨板，测其电阻并计算电阻率，从而确定电阻率的影响因素，利用模压技术将柔性石墨板压制成燃料电池的流场板，装配燃烧电池，测其放电性能曲线并与其它材料流场板组装的燃料电池的放电性能曲线进行了比较。     

Development of a mathematical model for the effect of temperature and relative humidity on the water vapour permeability of plastic films

The water vapour permeability constants of three flexible films (LDPE, PET and a laminate of both films) were determined at 20, 30 and 40 °C and from 55 to 90% relative humidities. The relationship between permeability and temperature followed the Arrhenius model for the three films. The relative humidity also influenced the permeability of the films. A mathematical model describing permeance (P/X - the permeability of laminates or films) as a function of external relative humidity and temperature was developed. The model can be used to predict the permeance of the three films at different temperatures and relative humidities.     

软包装材料透氧率对食用油氧化特性的影响

通过恒温加速实验,运用分光光度法测定不同透氧率的软包装材料中的食用油的过氧化值,分析了不同透氧率的软包装材料对食用油氧化特性的影响,理论上含铝箔或镀铝材料的氧化速率较小。结果表明:不同透氧率的包装材料对食用油的氧化影响是显著的;在进行盒中袋内袋材料的选择时,选择透氧率低的包装材料是合理的。     

Nanoimprinting of Flexible Polycarbonate Sheets with a Flexible Polymer Mold and Application to Superhydrophobic Surfaces

This study demonstrates a reliable process for the direct nanoimprinting of a flexible polycarbonate (PC) sheet using a perfluoropolyether (PFPE) mold. PC is a commonly used flexible substrate with optical transparency, low thermal expansion coefficient, high mechanical strength, and excellent deformation resistivity. The imprint performances of PFPE, hard/soft‐polydimethylsiloxane, and silicon molds are compared. Given that the heating temperature is near the glass transition temperature (≈153 °C) of PC, only PFPE mold can be fully patterned into PC substrate with viable integrity. The mechanical property and gas permeability of the materials are investigated to determine the mechanism of the flexible PFPE mold, which performs better than a rigid silicon mold. Nanoimprint process using a PFPE mold is performed at 153 °C and 5 bars. The lower imprint temperature or imprint pressure of the proposed process compared with those from previous studies is favorable in nanoimprinting. Finally, nanoroughness‐on‐nanopillar hierarchical surfaces, which possess superhydrophobic slippery characteristics superior to those of nanoroughness‐only surfaces, are obtained by treating PC nanopillar arrays imprinted by PFPE mold with C₄F₈ plasma.     

多层复合包装材料的气体渗透性

系统地讨论了高分子材料的气体渗透性，并从单层包装材料的渗稼性理论导出层合包装材料的渗稼系工，讨论相对湿度对气体渗透的影响及如何计算多层结构中的阻隔层的相对湿度。给出的结果对设计多层复合包装材料有重要的参考价值。     

Low temperature processing of Mn–Zn nanoferrites

Mn_0.4Zn_0.6Fe₂O₄ ferrite synthesized by coprecipitation method is investigated in the present work. D.C. resistivity is studied as a function of temperature and values upto 10² times greater than those for samples prepared by the conventional ceramic method are observed. It is found that resistivity decreases with increase in temperature. The initial permeability values are high as compared to those prepared by soft chemical route. Initial permeability is found to increase with increase in temperature. At a certain temperature, called the Curie temperature, it attained a maximum value, after which the initial permeability is found to decrease. Even at nanolevel, appreciable value of initial permeability is obtained. The particle size is calculated using Scherrer equation for Lorentzian peak, which comes out between 9 nm and 19 nm. Possible mechanisms contributing to these processes have been discussed.     

盒式气调包装下温度对薄膜透气性能的影响

以高阻隔膜、双层膜、聚丙烯(PP)膜及双向拉伸聚丙烯(BOPP)膜为材料,采用小袋法,分析了盒式气调包装下,各薄膜在4,10,25,30℃温度下的薄膜透气系数和透气系数比的变化规律。结果表明:随着温度的升高,4种薄膜的透气系数都呈上升趋势;同时,高阻隔膜和双层膜的透气系数比显著降低,而BOPP膜和PP膜的透气系数比则逐渐升高。同一温度条件下,PP膜的透气性能最好,BOPP膜次之,双层膜和高阻隔膜的透气性能较低。试验中,透气系数的自然对数与绝对温度的倒数满足阿累尼乌斯方程,以此可求得不同薄膜材料在其他温度下的透气系数。     

钴含量对锰锌铁氧体磁导率温度稳定性的影响(英文)

采用溶胶凝胶自燃烧法制备了Mn0.4Zn0.6-xCoxFe2O4铁氧体,研究了钴掺杂对其结构和磁性质的影响。将自燃烧法制备的粉末进行1,150℃烧结。利用X射线衍射仪对制备的粉末测试发现,Mn0.4Zn0.6-xCoxFe2O4系列铁氧体都具有尖晶石结构。利用VSM对铁氧体进行磁性测试,发现饱和磁化强度与晶格常数的变化规律一致,在钴含量为0.2时,都取得最大值。通过μi-T曲线发现,初始磁导率随着钴含量的增加而降低,居里温度是一个常数。而且,钴含量可以调节磁导率的温度稳定性,在钴含量为0.3时,磁导率具有优良的温度稳定性。基于铁氧体中离子分布的原理,阐明了钴掺杂对铁氧体磁导率温度稳定性的作用机理。     

用于应力监测的新型平面柔性涡流传感器

针对直升机旋翼轴应力监测的需求和轴部安装空间有限的实际情况,研制了一种新型平面柔性涡流传感器,并提出了相应的应力监测方法.该方法利用磁弹效应,通过建立平面涡流传感器和铁磁性被测对象的有限元仿真模型,得到传感器阻抗变化与对象磁导率的测量网格数据,可实现铁磁性被测对象的非接触或接触应力监测.搭建了拉应力实验平台,通过实验,验证了该方法的可行性,并得到了磁导率与拉应力的线性关系式,测量了增加的残余应力值.     

In-plane permeability characterization of the vacuum infusion processes with fiber relaxation

In vacuum infusion processes fiber preforms are placed onto the single molding surface and enveloped with a non-rigid polymer bag which is sealed to the molding surface. The flexible bagging film does deform during the resin infusion process thus changing the compaction of the fabric. However, one can also relax the preform by drawing a partial vacuum in a rigid chamber placed on top of the flexible bag which will increase the permeability of the fabric under the chamber. A numerical model is presented to characterize the change in permeability and describe the mold filling for such processes in which the fabrics undergo controlled relaxation by external stimuli. The predictions from the simplified model agreed reasonably well with the experiments. This characterization and resin flow front prediction with time method should prove useful in processes such as Vacuum Induced Preform Relaxation (VIPR) process which can be used to actively manipulate flow in a vacuum infusion process.     

温度对保鲜膜透气和透湿性能的影响

在不同温度下测定聚乙烯、聚氯乙烯保鲜膜的氧气、二氧化碳渗透系数和水蒸气渗透率,并用Arrhenius公式关联温度与各个渗透系数和渗透率。根据Arrhenius公式,温度与各个渗透系数和渗透率之间具有很好的相关性,相关系数均在0.97以上。给出了温度与各个渗透系数和渗透率之间的关系式,可以计算出任何温度下聚乙烯保鲜膜的氧气、二氧化碳渗透系数和水蒸气渗透率。