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材料真空出气性能是卫星设计选材时的一个重要依据,辐照是对材料出气性能影响较为严重的一种空间环境因素。本文对Co源辐照(1.2×10~9rad,Si)前后的材料样品,进行100及125℃条件下真空出气参数试验;结合红外光谱、扫描电镜、热重分析测试手段,研究辐照环境对聚乙烯电缆护套材料(SF-30-35)出气性能的影响。研究表明:经过辐照后的聚乙烯电缆护套材料样品的总质量损失及可凝挥发物量真空出气参数显著增加;Co源辐照使材料性质发生很大变化,辐照前材料表面为韧性网状结构,辐照后材料表面明显硬化,力学性能由柔韧变为干脆易断;辐照使材料发生氧化断链及交联反应,真空出气试验时断链产生的分子逸出。上述结果说明辐照环境改变了电缆护套材料特性,加速了材料真空环境下的出气性能。 相似文献
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《真空科学与技术学报》2017,(10)
航天器材料在空间环境下的出气容易造成敏感系统的污染,并带来负面效应。对航天器出气污染的预估仿真,首先需要材料出气特性参数和模型作为输入。以RTV胶为对象,基于阶跃加热的方式对材料进行出气量原位测试,分析获得了材料出气的主要特性参数,建立了多个温度下的出气预测模型,为卫星在轨动态污染水平的仿真和预测提供输入。 相似文献
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含砷废渣作为一种持久性污染物被广泛关注,固化/稳定化技术是治理含砷废渣的一种行之有效的途径。对硅酸盐水泥基胶凝材料固砷效果以及其固化机理等方面的研究进行了综述,水泥水化过程中产生的大量Ca(OH)_2与可溶性砷酸盐反应生成较为稳定的砷酸钙盐,降低砷的浸出浓度,从而实现砷的有效固化,但其存在污染物包容量小、耐久性差等缺点。本课题组提出了利用地聚物水泥(地聚物材料)固化含砷废渣,通过在地聚物材料水化聚合过程中,以同晶取代的方式实现AsO43-与SiO_4~(4-)、AlO_4~(5-)之间的化学键合,并辅以地聚物材料的高强、耐久性好的优良特性,利用地聚物材料固化含砷废渣实现砷的大容量、持久性地安全稳定固封。 相似文献
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《真空与低温》2015,(5)
为了精确地预测污染物对卫星系统性能的影响,许多国家制定了相应的航天器材料出气动力学测试方法,其中美国材料与试验协会(ASTM)制定的ASTM E1559航天器材料出气污染特性测试标准更为先进。此测试方法与以往实验方法相比,可以对材料出气特性进行原位测量,并且可以获得与时间和温度相关的沉积动力学模型。文中介绍了几种常用的航天器材料出气动力学测试方法,着重介绍了ASTM E 1559测试方法的主要内容,基于这种方法的国内外的应用,最后对该方法进行分析得出:该方法可以进行原位测试,可以获得不同温度敏感表面的沉积特性,温度变化范围广,低温可达90 K,并且基于该方法,利用四极质谱仪可以对污染成份进行实时的分析,对我国基于ASTM E 1559实验方法应用具有参考价值,有助于提高我国对航天器材料出气污染预估水平。 相似文献
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塑料食品包装材料安全性研究现状 总被引:9,自引:6,他引:3
介绍了塑料食品包装材料中的污染物种类、污染物的分析方法以及污染物迁移到食品中的迁移模型。指出塑料包装带来的食品污染问题已经引起了世界各国的重视,各个国家纷纷制定了相应的法规以确保食品安全,最后指出了我国安全型塑料食品包装材料的研究方向。 相似文献
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Yong-Jin Seo Woo-Sun Lee Sang-Yong Kim Jin-Sung Park Eui-Goo Chang 《Journal of Materials Science: Materials in Electronics》2001,12(7):411-415
We have invetigated the slurry-induced metallic contaminations of undoped and doped silicate oxide surface during the post-chemical mechanical polishing (CMP) cleaning process. The metallic contaminations by CMP slurry were evaluated in the four different oxide films, such as plasma enhanced tetra-ethyl-ortho-silicate glass (PE-TEOS), O3-boro-phospho-silicate glass (O3-BPSG), PE-BPSG, and phospho-silicate glass (PSG). Prior to entering the post-CMP cleaner, all films were polished with KOH-based slurry. The total X-ray fluorescence (TXRF) measurements showed that all oxide surfaces are heavily contaminated by potassium and calcium during polishing, which is due to the CMP slurry. The polished O3 BPSG films presented higher potassium and calcium contaminations compared to PE-TEOS film because of a mobile ion gettering ability of phosphorus. For PSG oxides, the slurry-induced mobile ion contamination increased with an increase of phosphorus content. In addition, the polishing removal rate of PSG oxides had a linear relationship with phosphorus content. 相似文献
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P. P. Poluektov S. S. Shirokov O. V. Kholopova M. A. Chernikov S. K. Savin E. V. Shirokova 《Radiochemistry》2014,56(3):308-310
A pulsed decontamination apparatus was developed and tested. Its operation is based on the action of oscillating liquid flow on contaminated objects. It ensures efficient decontamination of items and parts of complex geometry with deep contaminations and with contaminations blocked by corrosion products. 相似文献
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A new approach to monitoring the quality of adhesive bonding in the carbon fiber--reinforced polymer (CFRP) is developed by using a local nonlinear response of the laminate. It is shown that a degraded (contaminated) boundary layer of the adhesive contributes to an overall nonlinear response of the laminate that enables to evaluate and quantify bonding quality caused by various types and levels of single contaminations. In the context of aviation applications, two typical stages during the life of a structural part for which the adhesive properties of a bonding joint could be degraded were considered: the production process and the maintenance/repair scenario. All kinds of single contaminations studied result in enhancement of the nonlinear response of the CFRP laminate, which is an indication of deterioration of the bonding quality. The effect of multiple contaminations confirms a cumulative decline of adhesion caused by increase of the contents of single contamination components. 相似文献
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成核剂的超临界分散及其效果的研究 总被引:1,自引:0,他引:1
采用超临界溶胀渗透法,将成核剂(DM和NA 21)分散到等规聚丙烯(iPP)的基体内部,结果表明,分散后成核剂的形态、聚集状态及均匀性与成核剂本身的性质有关。NA 21成核剂在iPP中以分子状态渗透并呈均匀分布,其自组装形成的纳米单元大小在50 nm~100 nm之间。M D成核剂则以分散前相似的棒状单晶形式排列,显示出明显的团聚。还采用Jez iorny方法拟合出非等温结晶动力学参数;并对溶胀渗透NA 21前后的iPP样品的结晶动力学进行了比较。 相似文献
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We report an experimental and theoretical study of the effects of interference in polymeric light-emitting diodes (LEDs). These effects are due to the complex optical structures of the devices, which include many layers of materials with different refractive indices, and are of considerable importance since they affect spectral distribution and intensity of the absorption and emission in a significant way. By way of comparison, they can also provide a flexible, noninvasive optical probe of the electroluminescent processes, such as, for example, the spatial distribution of the recombination inside the LED. In this paper we analyse single-layer diodes with indium-tin oxide (ITO) and Al electrodes, where poly(p-phenylene vinylene) (PPV) is the luminescent polymer. We find that photo-induced excitation of the radiative species produce different spectral shapes depending on the excitation energy (and hence on the profile of excited chromophores) which we can describe in terms of interference phenomena. The theoretical analysis is conducted by means of multilayer stack theory and transfer matrix calculations, and takes into account additional quenching effects due to In contaminations from the ITO electrode. The theoretical results are in good agreement with the experiment. 相似文献
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钢的硼-铬-稀土共渗层脆性行为研究 总被引:4,自引:0,他引:4
研究了钢的B-Cr-RE共渗层和渗硼层的脆性行为,表明,B-Cr-RE共渗层脆性明显低于渗硼层,且沿渗层不同深度的脆性分布呈“浴盆”型.进行适当渗后热处理可以降低渗层脆性.同时,对铬及稀土元素降低渗层脆性的机理作了探讨. 相似文献
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用仪表冲击的方法和系列冲击的方法测定了加入一定量成核剂的聚丙烯材料的冲击强度和断裂韧性(临界裂纹扩展力Gc)及其随成核剂含量变化的规律。结果表明,其冲击强度σ1和Gc均在成核剂0.4%的加入量处极大值。 相似文献