共存金属离子对碳纤维中碱金属、碱土金属离子测定的干扰影响

本文采用火焰原子吸收光谱法,对碳纤维中碱金属,碱土金属离子的含量及试样中共存金属离子的干扰影响作了研究。由于碳纤维中钾、钠、钙、镁等离子在高温下易电离,会降低原子吸收的灵敏度(其中钙原子吸收灵敏度下降趋势尤为显著)。为了提高钙原子吸收的灵敏度,本文选用了氯化锶、氯化铯、氧化镧等抑制剂抑制待测金属离子的电离,提高钙原子吸收的灵敏度。抑制剂既能消除共存金属离子的干扰影响,又能提高分析结果的准确度。     

实验《碱金属和碱土金属》存在问题的探究

针对无机化学实验教材中的实验《碱金属和碱土金属》,讨论了学生在实验过程中以及教材本身存在的问题,提出了解决这些问题的方法。     

金属氧化物对单组分缩合型室温硫化氟硅橡胶耐热空气老化性能的影响

研究了金属氧化物（二氧化锡、三氧化二铁和铁锡氧化物复合物）对单组分缩合型室温硫化氟硅橡胶（ＦＲ１）耐热空气老化性能的影响。结果表明,二氧化锡、三氧化二铁和铁锡氧化物复合物能提高ＦＲ１的耐热空气老化性能,使ＦＲ１的初始分解温度分别提高１５,１５和３０℃,并使ＦＲ１的热重曲线向高温方向偏移;二氧化锡和三氧化二铁在耐热空气老化方面有协同作用,铁锡氧化物复合物的耐热空气老化性能最好     

杂质对金河磷矿酸解反应特性的影响

采用正交实验法研究了杂质氧化镁、氧化铝、三氧化二铁、氧化钙、二氧化硅及其交互作用对硫酸分解金河磷矿的分解率的影响,得出了各因素的影响主次及显著性,以及该磷矿各组份的优化配比.     

碱土金属修饰的Co/RPSA催化剂催化分解N2O

以RPSA分子筛为载体,采用浸渍法制备了一系列以Co为主活性组分和碱土金属为助剂的CoM/RPSA（M=Mg、Ca、Sr和Ba）催化剂,考察了含硫和含氧条件下直接催化分解N2O的性能。采用X射线衍射、热重-质谱联用系统、NH3-TPD和N2O-TPD等方法对催化剂进行了表征。XRD结果表明,Co物种主要以Co3O4尖晶石形态存在。NH3-TPD和N2O-TPD结果表明,碱土金属的种类影响催化剂酸性和对反应物N2O的吸附-脱附性能,催化剂活性与催化剂酸性及其对反应物N2O的吸附-脱附性能有关。催化剂活性评价结果显示,CoSr/RPSA催化剂的N2O分解活性较好,N2O转化率达到95%时的反应温度为471 ℃。     

杂质对金河磷矿酸解反应特性的影响

采用正交实验法研究了杂质氧化镁、氧化铝、三氧化二铁、氧化钙、二氧化硅及其交互作用对硫酸分解金河磷矿的分解率的影响，得出了各因素的影响主次及显著性，以及该磷矿各组份的优化配比。     

典型碱金属、碱土金属对不同变质程度煤焦溶损反应的催化作用

试验研究发现,添加碱金属、碱土金属对低变质程度煤焦反应性的催化作用小于焦煤等中等变质程度煤焦反应性。它们对焦炭溶损反应的催化作用顺序为：K〉Na〉Ca〉Mg,且随着添加量的增加,催化作用越强。随反应时间和典型金属添加量的增加,以及温度的升高,焦炭转化率越大。     

高碱低阶煤热解及热解半焦研究进展

我国碱金属、碱土金属(AAEM)含量高的低阶煤储量丰富。高碱含量造成锅炉受热面结渣沾污及气化炉结块腐蚀等难题,低阶煤内水高、氧含量高、挥发分高、发热量低以及易氧化自燃等特性为其储、运、用带来极大的难题。热解可生产优质燃料和高附加值化工原料,也是燃烧、气化、直接液化等过程的起始阶段和/或伴随反应,煤在热解阶段发生的反应、经历的变化,对煤转化利用的效率和清洁程度起重要、甚至决定性作用。笔者对煤热解与热解半焦研究及进展进行综述性评价,着重探讨煤中AAEM对热解过程及半焦的影响。结果表明,热解研究装置模拟的工况与现代煤化工过程中煤热解所处环境相差甚远,半焦样的代表性不强使热解研究成果的指导意义不大;对煤中不同赋存形态AAEM的分离方法有待完善,还需筛选、尝试新的萃取试剂;基本掌握了煤热解过程中AAEM的变迁行为,但尚缺乏控制煤中AAEM危害的有效方法。高碱低阶煤的安全高效洁净转化利用技术仍待突破。     

杯芳烃衍生物与碱金属离子、碱土金属离子配合的研究进展

杯芳烃衍生物作为"第三代超分子",对金属离子有着优异的结合力和选择性,已广泛用于金属离子的萃取、离子色谱、催化、跨膜运输、离子通道以及自组装分子层等领域。综述了近年来杯芳烃及其衍生物与金属离子,主要是碱金属、碱土金属阳离子配合的最新进展。     

高级日用瓷无铅熔块釉的研究

本研究采用多种碱金属、碱土金属及稀土材料等复合熔剂的综合效应来代替铅釉中的铅元素，并通过实验总结出坯釉适应的一些规律，研制成功了适用于二次烧成的高档日用瓷无铅熔块釉。     

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.     

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…     

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。     

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.     

酚醛树脂热降解动力学研究

用热失重非等温法对不同甲醛,苯酚魔鬼洋比的酚树脂进行了热降解动力学研究。结果表明,甲醛,苯酚摩尔比为１．５时,酚醛树旨的热发活化能最高。耐热性最好。     

剪力对梁变形影响的分析

本文用材料力学的分析方法,导出了一个计入剪力时梁的挠曲线的微分方程式。为了估计剪力对梁变形的影响,在集中力作用下梁内剪力用一个单值连续的反三角函数表示。由能量法确定了截面因子数值之后,定量地给出计入剪力时梁变形的分析结果。其结果和弹性力学的结来是一致的。     

热塑性塑料熔体质量流动速度测量不确定度的评定

本文分析了聚丙烯熔体质量流动速率测量过程中不确定度的来源，并对各不确定度分量进行了评估。该测量过程中所产生的测量不确定度主要来源于测量重复性。