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利用氢化燃烧合成法制备了镁基储氢合金Mg-Mg2Ni,分析了镁镍配比和镁粉粒径对HCS产物组成和储氢性能的影响.研究结果表明,HCS产物主要由Mg2Ni及Mg的氢化物MgH2、Mg2NiH4和Mg2NiH0.3组成,没有Ni相的存在,当Mg:Ni>2:1时,较粗镁粉原料的使用对燃烧合成产物Mg2Ni的氢化活性影响不大,但会降低反应剩余Mg的氢化活性.随原料中镁镍配比的增加,HCS产物中MgH2的相对含量逐渐增加,HCS产物的氢化动力学性能逐渐降低,吸氢量却先增加后降低,Mg:Ni=7.85:1时具有最大的吸氢量4.87wt.%,同时由较细镁粉得到的HCS产物的氢化速率和吸氢量大于较粗镁粉,但两者之间的差别会随镁镍配比的降低而减小. 相似文献
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目的 建立利用燃烧氧化法测试包装用生物降解塑料中TOC含量的方法。方法 对已知含无机碳酸盐填料的样品,分别用盐酸进行酸化处理和不经酸化处理,研究用酸化样品对消除样品中无机碳酸盐干扰的效果;在不同温度下考察薄层纤维素的TOC测定结果,对燃烧温度进行优化;在优化后的条件下,采用碳酸钙作为碳含量的标准物质,对包装用生物降解塑料实际样品进行定量测试。结果 经酸化处理后的塑料样品,TOC检测值与理论值偏差仅为-1.22%~+1.42%,而不经酸化处理的塑料样品,实测值与理论计算值的偏差为+7.40%~+29.36%,可见经过酸化处理所得结果更为准确;在950℃到1250℃区间内,对薄层纤维素样品分别在不同温度下进行燃烧氧化测试,发现最佳燃烧温度为1 100℃;利用碳酸钙为标准品绘制标准工作曲线,结果表明在0.6~24mg碳含量内,标准工作曲线线性关系良好;对7个生物降解塑料实际样品进行检测,TOC实测值与理论计算值的偏差在-4.26%~+3.47%。结论 研究表明,该方法操作简便、线性良好,精密度和准确性高,适用于生物降解塑料中TOC的检测。 相似文献
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设计合成了双功能共聚单体3-羧基-3-丁烯酰胺(CBA),采用溶液聚合的方法制备丙烯腈二元共聚物作为碳纤维前驱体,详细研究了单体配比对聚合反应、聚合物结构和预氧化性的影响。结果表明,随着单体投料中CBA含量的增加,聚合物中CBA含量增加,而相对分子质量和转化率均逐渐降低;红外光谱和差示扫描量热分析表明CBA单体能够通过离子机理引发环化,使预氧化温度降低60℃以上,且随着CBA单体含量的增加,离子环化反应加强,放热速率降低,有利于避免集中放热,CBA可以明显改善聚丙烯腈(PAN)的预氧化性能,有利于制备高性能碳纤维。 相似文献
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We investigate the process of hydrogen sorption by nanoporous carbon at temperatures of 570–970 K by using the method of thermodesorption spectrometry. Thermodesorption spectra consist of several phases caused by chemisorption in several independent states on the surface of nanoporous carbon. Each of the states is characterized by the activation energy and pre-exponential factors of desorption rate constants. We obtain estimates for the efficient activation energy and heat of sorption. 相似文献
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通过酯化反应和自由基共聚反应制得木质素磺酸盐-丙烯腈共聚物(P(LS-AN)),采用静电纺丝技术将其制成纳米纤维,再经预氧化和碳化处理,制得碳纳米纤维。采用红外光谱仪(FTIR)、差示扫描量热/热重同步分析仪(DSC/TG)、扫描电子显微镜(SEM)和拉曼光谱仪(Raman)对P(LS-AN)、电纺纤维及其碳纳米纤维的结构进行表征。结果表明,P(LS-AN)纳米纤维具有良好的热稳定性,在较高升温速率(10℃/min)下对其进行预氧化和碳化处理,所制得的碳纳米纤维单丝间未产生粘连。在碳化过程中,LS的苯酚结构有利于促进有序碳结构的形成,使得碳纳米纤维的结构更为完善。 相似文献
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Pashkevich D. S. Zimin A. R. Kapustin V. V. Petrov V. B. 《Journal of Engineering Physics and Thermophysics》2021,94(4):963-971
Journal of Engineering Physics and Thermophysics - The objective of the work was to thermodynamically substantiate the method of obtaining hydrogen fluoride from uranium hexafluoride by its... 相似文献
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在一透明有机玻璃块上钻孔,填满延期药(铅丹∶硅=85∶15),在一端安装电极,置于一耐压钢质容器内,容器压力可在实验前充气调节,可认为延期药燃烧时容器内压力恒定。高速摄影仪记录燃烧波阵面移动过程,观察发现,燃烧波阵面向前传播线速度不是定值,而是有节奏的"闪烁"跃进。亮时前进速度较快,暗时则较慢。通过计算图片张数得到小区间燃烧速度,对比发现燃烧速度是脉动的,脉动周期宽度约为1.0 mm,时间约14 ms。分析认为:脉动原因是加热区热分解产生的气体膨胀,使正在燃烧的延期药位移产生裂隙,其阻碍了加热区加热,使燃速降低,所以产生燃烧脉动;脉动周期不稳定的原因是火药密度不均或混药不均。通过改变预设压力,使延期药在不同压力下燃烧,对比发现,随着压力增大,燃烧速度呈一次线性加速。 相似文献
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Characteristics of Hydrogen Storage Alloy Mg2Ni Produced by Hydriding Combustion Synthesis 总被引:1,自引:0,他引:1
Qian LI Qin LIN Lijun JIANG Kou-chih CHOU Feng ZHAN Qiang ZHENGResearch Center of Energy Materials Technology General Research Institute for Nonferrous Metal Beijing ChinaDepartment of Physical Chemistry University of Science Technology Beijing Beijing China 《材料科学技术学报》2004,20(2):209-212
A high activity and large capacity of hydrogen storage alloy Mg2Ni by hydriding combustion synthesis was investigatedby means of pressure composition isotherms, X-ray diffraction and scanning electron microscopy. The results showedthat the maximum hydrogen absorption capacity of Mg2Ni is 3.25 mass fraction at 523 K, just after synthesis withoutany activation. The relationships between the equilibrium plateau pressure and the temperature for Mg2Ni were lgp(0.1 Mpa)=3026/T 5.814 (523 K≤ T ≤623 K) for hydriding and Igp (0.1 Mpa)=-3613/T 6.715 (523 K≤T ≤623 K) for dehydriding. The kinetic equation is [-ln(1 - α)]3/2 = kt and the apparent activation energy for thenucleation and growth-controlled hydrogen absorption and desorption were determined to be 64.3±2.31 kJ/(mol.H2)and 59.9±2.99 kJ/(moI.H2) respectively. 相似文献
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The thermodynamics and kinetics of pyrolytic carbon deposition via hydrogen reduction of CCl4 were studied. Thermodynamic analysis of the C–Cl–H system was used to determine the compositions of the gas and condensed phases at CCl4 : H2 = 1 : 4 to 1 : 90, temperatures from 700 to 1400 K, and a pressure of 105 Pa. The reactions leading to the formation of solid carbon in the H2–CCl4 system were considered, and the deposition parameters were optimized in terms of carbon yield. 相似文献