X射线衍射法对树脂炭微观结构测试分析

用X射线衍射法对不同条件下制备的酚醛和糠醛树脂炭进行了测试分析.酚醛树脂620 ℃炭化处理后样品开始出现微弱的(100)晶面衍射峰,表明已产生了一些石墨微晶.当炭化温度达1 000 ℃时,(006)和(110)晶面衍射峰也开始出现.但从总的趋势上看,1 000 ℃处理的酚醛树脂炭化产物石墨化程度还较低,仍属于无定形炭范围.620 ℃炭化处理的糠醇炭化样品则出现了明显尖锐的(100)晶面特征衍射峰,同时在衍射角为65°和82°附近,还发现了(110)晶面和(006)晶面产生.在较低温度炭化处理后能同时观察到几种表征石墨化程度的特征衍射峰,表明糠醇树脂是一种较易石墨化的有机高分子材料.     

电沉积条件对甲基磺酸锡镀层织构的影响

为了在实际应用中控制甲基磺酸电镀锡镀层的织构以提高镀层性能,采用X-射线衍射分析方法研究了镀锡工艺中表面活性剂浓度、电流密度和镀层厚度对镀锡层织构的影响规律,XRD分析结果显示,表面活性剂聚乙二醇辛基苯基醚(OP)浓度高,镀层以(211)和(321)晶面择优;OP浓度低,镀层以(101)和(112)晶面择优低电流密度有利于镀层以(211)和(312)晶面择优,高电流密度则有利于(101)和(112)晶面择优;镀层较薄时没有明显的晶面择优,(211)晶面的衍射峰强度随着镀层厚度的增加而加大,当镀层厚度超过10μm镀层以(211)和(321)晶面的衍射峰为主,且基本不随镀层厚度的增加而变化.由于晶态基底会影响镀锡层的织构和形貌,本甲基磺酸镀锡工艺以多晶紫铜化学镀非晶态镍磷合金为阴极,对非晶态基底上得到的锡镀层进行研究。     

非离子表面活性剂改性羟基磷灰石粉体的制备

采用化学沉淀法将硝酸钙、磷酸氢二铵按摩尔比5:3配成溶液,加入不同质量非离子表面活性剂聚乙二醇(PEG)、聚乙烯醇(PVA),使其质量占羟基磷灰石(HA)质量分别为1％、2％、3％、4％、5％,经750℃热处理2 h,从而制取表面活性剂改性的HA粉末.对粉末进行粒度分布测量、FT-IR测试、XRD衍射分析和SEM表征.结果表明:常压60℃下制备改性的HA粉末纯度高,结晶度低.其中PEG改性HA粉末物相为Ca10(PO4)6(OH)2、Ca3(PO4)2和Ca2P2O7,添加3％PEG粉体中位径(D50)为13.55μm,OH-吸收峰最强,HA含量为纯相,结晶程度趋于完善;PVA改性HA粉末物相只有Ca10(PO4)6(OH)2,添加3％PVA粉体中位径(D50)为7.068μm,结晶程度趋于完善,HA粉末的团聚程度最小,比表面积最大为607.4 m2/kg.PVA对HA团聚程度的分散性优于PEG.     

引氟量对含氟羟基磷灰石纳米晶结构的影响

采用Ca(NO_3)_2·4H_2O-P_2O_5-NH_4F-乙醇体系,利用溶胶凝胶法在600℃获得不同含氟量的纳米含氟羟基磷灰石(FHA)粉体。通过X射线衍射分析(XRD)对纳米粉体进行了表征,讨论了不同引氟量对衍射峰强度、晶面间距、晶格常数及粒度的影响,并从FHA形成机理及结构构成方面解释了原因。结果表明,FHA主晶相衍射峰强度随引氟量增加,呈先减少后增加的趋势,晶面间距(特别是(300)晶面)逐渐减小,而晶格常数及粒度在a轴方向上亦呈现逐渐减少的趋势。     

电流密度对65Mn钢上镍基复合镀层结构的影响

在电流密度为2.5～16.0A/dm~2的条件下,于65Mn钢上制备了Ni-TiB_2复合镀层。使用扫描电镜观察了镀层的表面形貌,并使用X射线衍射仪对镀层的晶体结构进行了表征,分析了镀层的晶面取向和晶粒尺寸。结果表明:随着电流密度从2.5A/dm~2增大到16.0A/dm2,镀层的表面形貌发生明显变化,(111)、(220)和(311)晶面的衍射强度基本是逐渐减弱,而(200)晶面的衍射强度先逐渐增强后逐渐减弱。镀层的择优取向由(311)晶面转变为(200)晶面,平均晶粒尺寸先逐渐减小后增大。     

渔用自增强HDPE单丝的取向结构及力学性能

采用自增强技术制备了渔用自增强高密度聚乙烯(HDPE)单丝,通过广角X-射线衍射(WAXD)、声速法等比较了渔用自增强HDPE单丝和普通HDPE单丝的取向结构及力学性能。结果表明,渔用自增强HDPE单丝比普通HDPE单丝的晶面间距、晶胞参数和微晶尺寸稍大,结晶度、取向度、声速取向因子、断裂强度、结节强度和结强损失率增加。     

醇、酸类添加剂对脱脂清洗液清洗效果的影响

本文研究了清洗剂浓度、有机醇(R—OH)、无机酸(HA)和HA/R—OH对清洗液清洗效果的影响.结果表明随着清洗剂浓度的增加和R—OH、HA的加入,清洗液的脱脂清洗能力增强.同时给出了R—OH、HA和清洗剂较合适的配比范围.     

短纤维增强HA/PMMA生物复合材料

采用原位合成与溶液共混相结合的方法,制备了短切碳纤维(Cf)增强纳米羟基磷灰石(HA)/聚甲基丙烯酸甲酯(PMMA)生物复合材料.研究了Cf含量和长度对HA/PMMA力学性能的影响.采用万能材料试验机和扫描电子显微镜对Cf/HA/PMMA的力学性能及断面的微观形貌进行了测试和表征.结果表明,Cf在Cf/HA/PMMA中分布均匀,且有效提高CfHA/PMMA的力学性能;Cf的质量分数在4%左右时,Cf/HA/PMMA的拉伸强度、弯曲强度、压缩强度和弹性模量等均达到极大值;Cf/HA/PMMA的断裂伸长率随Cf含量的增加而减小.当Cf含量一定时,随Cf长度的增加,Cf/HA/PMMA的拉伸强度、弯曲强度和弹性模量均增加,断裂伸长率降低.     

烧结锶铁氧体的极图分析

将不同强度取向磁场下湿压成型的生坯在1 190℃烧结2 h,获得锶铁氧体烧结磁体.采用X射线极图分析样品的织构取向特征,根据Stoner-Wohlfarth模型,建立了描述取向度的表示方法.分析表明:在磁场下成型的样品{001}晶面族衍射峰强度显著增强.用(008)晶面极图描述磁体取向度时,随取向磁场强度的增大,晶粒取...     

稀土掺杂纳米氧化锌的制备及光学性能研究

低温水热法合成了直径分别为11~48和9~15 nm的棒状氧化锌和稀土La~(3+)掺杂氧化锌微粒。通过X-射线粉末衍射(XRD)、透射电子显微镜(TEM)、紫外-可见漫反射光谱(UV-vis DRS)和荧光光谱(PL)等对氧化锌结构进行了表征以及光学性能测试。结果表明,本研究制备的纳米Zn O是结晶良好的棒状晶体,La~(3+)的掺入使氧化锌晶体发生了晶胞膨胀,紫外吸收增强,带隙向紫外区偏移,随La~(3+)掺杂浓度的增大,荧光强度增加。     

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…     

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.     

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。     

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。