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生石油针状焦经４８小时三磨成〈５μｍ的细粉后，具有良好的自粘结性能和烧结性能，不用添加粘结剂夺型烧结即可制得高强高密碳石墨材料，研磨时间对粉末的形态、石墨化性能和烧结性能有重要影响。 相似文献
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研究了热处理温度，Ｈ３ＢＯ３溶液质量浓度和ＣＦ在Ｈ３ＢＯ３溶液中的浸泡时间等因素对ＰＡＮ基ＣＦ力学性能和电学性能的影响。并通过考察加和未添加Ｈ２ＢＯ３的ＣＦ分别经高温石墨化热处理后在结构和性能上的差异，对硼在ＰＡＮ基ＣＦ高温热处理时的促进石墨化作用进行了初步探讨。 相似文献
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灰铸铁中石墨分布形态对性能的影响 总被引：2，自引：0，他引：2
晋芳伟 《云南农业大学学报(自然科学版)》2000,15(2):139-141
研究了HT200-400灰铸铁的石墨长度、石墨量对铸铁力学性能的影响。结果表明：石墨量<15%,石墨长度在50～200 μm范围内的铸铁,性能优良,加工光洁度高。用回归分析法建立了强度与硬度的回归方程。 相似文献
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本文通过石墨共沉淀这一化学改性法，证实廉价易得的石墨材料对Mno_2电极的可充性有一定的改善。经过化学反应使Mn（OH）_2与石墨共沉淀，通氧气使Mn（OH）_2氧化成Mn_2O_3，干燥脱水后的Mn_2O_3再经酸化歧化成为所需MnO_2样品，并探讨了石墨选型对MnO_2电极改性的影响． 相似文献
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有机锗的抗癌作用已引起人们的关注,用石墨炉原子吸收法测定锗的报道很少,测定锗的困难在于试样中的锗在原子化之前以易挥发的 GeO 形式损失掉了,影响分析准确度。本试验采用在热解石墨管内涂难熔金属层,使石墨管表面性质得到改善并采用镁和钯为改进剂,对降低基体干扰获得了明显效应 相似文献
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孟凡胜 《中国农业科技导报》2009,11(Z1):22-23
研究了在石墨炉原子吸收光谱法分析条件下,饲料中钙、磷、硫、锰、镁、钾和氯化钠等成分对铅测定的影响。结果表明,磷、钙、硫、钾和氯化钠对铅测定的影响比较大;镁和锰的影响比较小。 相似文献
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黄火盛 《厦门水产学院学报》1985,(1):75-81
本文在分析TDR—C型、含Cr、Mo、W、V堆焊焊条性能、特点与作用的基础上，提出了研制一种新的、石墨型药皮的“堆328”堆焊焊条，以满足生产实践中对于堆焊层金属性能的更高要求。设计、试验了新的石墨型药皮的配方，进行了焊条的试制和试验堆焊、以及在生产中的应用、均获得良好结果。与常用的“堆322”堆焊焊条比较，石墨型“堆328”堆焊焊条的堆焊工艺性能良好；合金元素过渡系数高；堆焊层金属硬度较高，因而其耐磨性能有较大的提高。用石墨型“堆328”堆焊焊条堆焊修复的零件，其耐磨性能(使用寿命)比用“堆322”焊条堆焊的要高2倍左右，因而石墨型堆焊焊条“堆328”具有明显的技术经济效益，值得推广使用． 相似文献
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杉木间伐材炭化过程微观机制分析 总被引：2，自引：0，他引：2
对不同炭化条件所得炭化物的FTIR光谱进行分析, 得出杉木间伐材加盖法炭化过程炭化物中微晶生成情况与表面官能团随温度的变化规律 结果表明, 炭化温度在600℃以下, 炭化物中较难形成高聚合度的芳核; 600~700℃间芳构化程度迅速提高, 其中发生大量-OH的脱水、脱氢反应, 在碳网间形成烷醚键、芳醚键; 经更高温度的结构重整, 部分炭化物从碳网畸变的交叉连接格子构造逐步转化成平面碳网为主的石墨状微晶结构; 结构重整过程中表面官能团发生了明显变化, 900℃的炭化物表面重新出现了酚-OH等基团 相似文献
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Cai W Piner RD Stadermann FJ Park S Shaibat MA Ishii Y Yang D Velamakanni A An SJ Stoller M An J Chen D Ruoff RS 《Science (New York, N.Y.)》2008,321(5897):1815-1817
The detailed chemical structure of graphite oxide (GO), a layered material prepared from graphite almost 150 years ago and a precursor to chemically modified graphenes, has not been previously resolved because of the pseudo-random chemical functionalization of each layer, as well as variations in exact composition. Carbon-13 (13C) solid-state nuclear magnetic resonance (SSNMR) spectra of GO for natural abundance 13C have poor signal-to-noise ratios. Approximately 100% 13C-labeled graphite was made and converted to 13C-labeled GO, and 13C SSNMR was used to reveal details of the chemical bonding network, including the chemical groups and their connections. Carbon-13-labeled graphite can be used to prepare chemically modified graphenes for 13C SSNMR analysis with enhanced sensitivity and for fundamental studies of 13C-labeled graphite and graphene. 相似文献
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We report the synthesis of tubular graphite cones using a chemical vapor deposition method. The cones have nanometer-sized tips, micrometer-sized roots, and hollow interiors with a diameter ranging from about 2 to several tens of nanometers. The cones are composed of cylindrical graphite sheets; a continuous shortening of the graphite layers from the interior to the exterior makes them cone-shaped. All of the tubular graphite cones have a faceted morphology. The constituent graphite sheets have identical chiralities of a zigzag type across the entire diameter, imparting structural control to tubular-based carbon structures. The tubular graphite cones have potential for use as tips for scanning probe microscopy, but with greater rigidity and easier mounting than currently used carbon nanotubes. 相似文献
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Zhou O Fleming RM Murphy DW Chen CH Haddon RC Ramirez AP Glarum SH 《Science (New York, N.Y.)》1994,263(5154):1744-1747
Previous high-resolution electron microscopy (HREM) observations of the carbon nanotubes have led to a "Russian doll" structural model that is based on hollow concentric cylinders capped at both ends. The structures of the carbon nanotubes and particles were characterized here by bulk physical and chemical property measurements. The individual nanostructure is as compressible as graphite in the c axis, and such nanostructures can be intercalated with potassium and rubidium, leading to a saturation composition of "MC(8)." These results are counter to expectations that are based on a Russian doll structure. HREM after intercalation with potassium and deintercalation indicates that individual nanoparticles are a "paper-mache" of smaller graphite layers. Direct current magnetization and electron spin resonance measurements indicate that the electronic properties of the nanostructures are distinctly different from those of graphite. Although the nanostructures have distinct morphologies and electronic properties, they are highly defective and have a local structure similar to turbostratic graphite. 相似文献
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Real-space observations of long-range electronic perturbations caused by defects have been made with scanning tunneling microscopy. The defects are isolated adsorbed molecules on the surface of graphite. These defects perturb the charge density, giving periodic oscillations similar to Friedel oscillations. The oscillations have a wavelength radical3 times that of the graphite lattice, and the symmetry of the oscillations reflects the nature of the defect. 相似文献
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The scanning tunneling microscope (STM) can be used to measure current-voltage characteristics on an atomic scale. The attachment of copper phthalocyanine molecules, in contrast to a variety of other molecules, to graphite changes the electrical characteristics of the STM from relatively symmetric to highly asymmetric or rectifying. Evidence is presented to show that the asymmetry arises because of the electronic energy levels of the copper phthalocyanine. The organic molecules were bonded to the graphite by an acid-base reaction that may have wide applicability. 相似文献
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于2013年7月(夏季),10月(秋季),12月(冬季)和2014年4月(春季)对东苕溪下游9个样点大型底栖动物功能摄食类群和营养盐状况进行了季节性调查,并采用摄食均匀度指数(Feeding Evenness Index,j_(FD))评价东苕溪下游生态系统健康状况。结果表明,该河段底栖动物摄食类群以收集者为主,且各摄食类群在季节间差异不显著(P0.05),说明东苕溪下游小微颗粒有机物丰富。冗余分析(Redundancy Analysis,RDA)表明功能摄食群在各个季度中均与总氮关系最为密切。j_(FD)值表明东苕溪下游整体生态系统健康状况较好,但个别样点较差。这说明该河段可能存在点源污染,且生境可能出现片段化。 相似文献
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本文报道了应用Ｘ－射线衍射分析及其它一些实验手段，研究钼在石墨炉内石墨探针表面上的原子化机理。结果表明：钼的原子化源于它的碳化物的热离解。 相似文献