4种炭素材料的抗氧化性研究

采用SEM、Raman光谱和TG-Dsc等手段研究了纳米碳管、天然石墨、酚醛树脂热解炭、炭黑改性酚醛树脂热解炭的抗氧化性.研究表明,这4种炭素材料的抗氧化性由强到弱的顺序为天然石墨、纳米碳管、炭黑改性酚醛树脂热解炭、酚醛树脂热解炭.     

合成树脂浸渍含量对炭素机械密封材料

主要研究酚醛树脂的浸渍含量对炭素机械密封材料的机械,物理性能的影响,同时对炭石墨材料浸渍酚醛树脂的浸渍机理及酚醛树脂固化机理作了初步的探讨。     

合成树脂浸渍含量对炭素机械密封材料性能的影响

主要研究酚醛树脂的浸渍含量对炭素机械密封材料的机械,物理性能的影响,同时对炭石墨材料浸渍酚醛树脂的浸渍机理及酚醛树脂固化机理作了初步的探讨。     

沥青与糠醛树脂混合作为炭制品浸渍剂的研究

一、前言在炭素材料的开发过程中,工艺性能良好的树脂浸渍剂一直是一个重要的研究课题。人们通常所使用的树脂浸渍剂如酚醛、环氧、糠醇、呋喃、聚酰亚胺等,其残炭率较低,裂解炭的体积收缩大和难石墨化,它们满足不了炭素材料各种性能的要求。因此为改进这些树脂浸渍剂所存在的问题,人们进行了广泛的研究。例如合成高残炭率的可石墨化的二甲     

悬浮共聚法处理石墨对石墨／沥青基炭材料性能影响

采用悬浮聚合法处理石墨表面,在石墨颗粒表面均匀包裹上一层树脂,使用热压方法制备的炭材料弯曲强度大大提高,达到44.68 MPa,而且炭材料的正面弯曲强度与侧面弯曲强度基本一致,有利于缓解热压烧结所引起的炭材料的各向异性.从红外光谱(FT-IR)分析得出,经过处理的石墨表面存在大量的C-O-C,C-O-H官能团;用环境扫描电子显微镜(SEM)观察样品弯曲断口的组织结构,发现未处理的石墨断口具有明显的层状结构,经处理后,层状结构被扭曲,随着树脂含量的增多,层状结构越不明显.     

机械用炭素材料

机械用炭素材料炭素材料具有良好的耐高温、耐腐蚀及自润滑性，使其在密封领域获得广泛应用。但普通炭一石墨材料强度低、开孔率大，用于流体密封，承压力低，密封性差，必须经过浸渍煤沥青、各种树脂或低熔点金属及其盐类，再经适当的固化，炭化或其它烧结处理。目前，这...     

TiC改性炭石墨材料的微观结构与性能研究

研究了在炭石墨材料基料中均匀掺杂TiC陶瓷粉体，经高温烧结、原住合成反应、石墨化，制备了TiC改性炭石墨复合材料。研究了TiC改性炭石墨复合材料的微观结构，分析了TiC掺杂对炭石墨材料力学性能的影响，并从微观角度解释了TiC对炭石墨材料力学性能影响的机理。从研究结果可以看出，TiC掺杂可使炭陶瓷复合材料的抗折强度提高13．4％，抗压强度提高38．1％，气孔率降低16．9％；其机理在于TiC掺杂在炭陶瓷复合材料制备过程中能促进石墨化，使晶体更加完整、细化，有利于力学性能的提高。     

炭素材料热稳定性能的研究

采用了热分析仪和差示量热扫描仪等对若干类别的炭素材料的热稳定性能进行了系统分析研究。研究发现,炭素材料制备工艺及骨料粒度对其抗氧化性能影响很大,炭制品的低温抗氧化性能不及石墨制品,石墨接头材料的高温抗氧化性能不及石墨电极材料。石墨制品骨料粒度越小,高温抗氧化性能越差。     

包混材料

包混材料是在研制高温气冷堆用炭／石墨材料的过程发展出来的，它与常规炭／石墨材料的区别在于独特的粉料制备工艺，这种工艺使每一个骨料颗粒的表面都均匀地包覆上一层粘结剂，因此骨料之间的每一个接触点都是有效的连接，这种材料在相同的强度下，其密度可以比常规炭／石墨材料的低，孔隙均匀，通孔发达，具有广阔的应用前景，这种粉料制备工艺也可用于SiC及其他陶瓷制品。     

树脂包覆对石墨化中间相沥青炭微球电化学性能的影响

以中间相沥青炭微球(SSGMCMB)为核、酚醛树脂(PR)热解炭为壳，采用浸渍一固化一炭化手段制备出树脂热解炭包覆SSGMCMB复合材料，并对其电化学性能进行了研究。通过SEM、XRD、恒电流充放电测试等手段研究了不同树脂包覆量对该复合材料的形态、结构及其电化学行为的影响，结果表明：树脂热解炭对SSGMCMB有较好的包覆作用，保持了SSGMCMB的球形形态，有利于锂离子的嵌入／脱出反应，对其电化学性能有一定的提高，改进了酚醛树脂热解炭有较大电压滞后的问题。     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

用两个形状指数表征粉煤灰颗粒形貌的研究

引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。     

典型煤碳燃烧特性研究和数值模拟

本文以三种典型煤的碳燃烧为研究对象，分别采用简单一维沉降燃烧方式和等温加热燃烧方式，实验研究了煤在快速加热条件下，其碳的初期和中，后期燃烧过程。以实验为基础，建立了煤的碳燃烧模型，变工况数值模拟了煤的碳燃烧过程，揭示了煤不同条件下的单颗粒碳燃烧特性。