机械活化黄铁矿的储能研究

采用自行研制的机械化学热量仪在303.15 K下对机械活化黄铁矿进行了在线储能研究。结果表明:湿磨时黄铁矿最大储能为361.5 J/g,活化效率为20.5%;干磨时黄铁矿最大储能为338.3 J/g,活化效率为16.1%。粒度和X射线衍射分析表明,活化后黄铁矿粒度减小,晶格发生畸变。     

润磨活化机理初探

通过SEM、X衍射分析、激光粒度分析以及比表面积和润湿热的测定 ,对润磨预处理铁精矿的活化机理进行了研究。研究表明 ,润磨后精矿平均粒径明显减小 ,细粒含量增加 ,- 4 5 μm粒级增加近 11% ,而 1～ 10 μm粒级由 13%提高到 2 0 %。粒径的对数值接近正态分布。精矿的润湿热由 1.4 5× 10 - 5J cm2 提高到 4 .77× 10 - 5J cm2 。衍射峰趋于变宽 ,衍射强度趋于减弱 ,晶格变形增加     

纳米镍粉的粒度分析

纳米材料的性质强烈依赖于其颗粒和晶粒的大小，测量纳米颗粒或晶粒尺寸无论从粉体制备还是从应用上都具有重要的意义。本文针对纳米镍粉进行了一系列粒度分析研究，包括SEM、TEM、激光粒度分析法、比表面分析法、X射线衍射法和X射线小角度散射法(SAXS)。不同的研究手段得到的纳米镍粉的粒径不尽相同。比较各种研究手段得到的结果可以知道其准确程度，并且针对不同的分析要求可选择不同的方法。     

Fe-Ni-B非晶纳米粒子不同处理后表面组成和结构的研究

对Fe-Ni-B非晶纳米粒子表面施加了单宁酸和重铬酸钾处理后，采用X射线光电子能谱和透射电子显微镜等技术对处理后粒子的表面组成和结构进行了分析。结果表明，单宁酸和重铬酸钾处理均可以提高Fe-Ni-B非晶纳米粒子的饱和磁化强度，且后者的提高幅度远大于前者。原因在于两种处理均使粒子的表面状态发生了有利于增强饱和磁化强度的变化，在表面形成了复合型氧化物NiFe2O4而重铬酸钾处理还在粒子表面形成了致密的Cr2O3层，阻挡了氧原子从表面向体内的扩散，减少了粒子的氧化态数量，从而使其饱和磁化强度得以大大提高。     

正极材料Li[Ni1/3Li1/9Mn5/9]O2的结构和充放电过程研究

应用X射线衍射,选区电子衍射和同步X射线衍射等方法,对锂离子电池正极材料Li[Ni_1/3Li_1/9Mn_5/9]O₂的结构和充放电行为进行了研究.结果表明Li[Ni_1/3Li_1/9Mn_5/9]O₂可标定为单相α-NaFeO₂,并具有$\\sqrt 3 $a_hex.×$\\sqrt 3 $a_hex.×$\\sqrt 3 $c_hex.超结构特征.电池充电时,伴随锂离子的脱出,相邻氧原子层间的静电斥力逐渐增大,当电压为3.8V时应力达到最大.接近4.6V时,晶胞常数c急剧下降,绝大多数Li⁺从材料的锂层拔出,Ni²⁺发生氧化.4.6~4.8V之间c增大,a变化很小,说明过渡金属层中的Li⁺拔出,而过渡金属离子的氧化状态未改变.     

金锡合金的机械合金化

应用机械合金化的方法合成了AuSn20化合物,X射线衍射及扫描电镜分析表明主要化合物成分为AuSn和Su5Sn.并对合金化的过程进行了阐述.     

钙盐浓度对复合氧化法制备多孔二氧化钛涂层表面结构的影响

为了分析微弧氧化电解液中钙盐浓度对复合氧化法(即预氧化和微弧氧化复合处理)制备多孔二氧化钛涂层表面结构的影响，利用X射线衍射、扫描电镜及附带的能谱对涂层的表面相结构、形貌及元素组成进行了观测与分析，利用图像分析软件对涂层表面孔隙率进行测试。结果表明：复合氧化法制备的多孔二氧化钛涂层表面均含有单质钛、锐钛矿型二氧化钛和金红石型二氧化钛：钙盐浓度的变化对涂层表面结构有一定影响，随着钙盐浓度的增加，涂层中锐钛矿型二氧化钛相对含量减少，金红石型二氧化钛相对含量增加；涂层表面的钙、磷元素含量降低，钙磷原子比增加：在所选钙盐浓度下，表面孔隙率的变化不十分显著。     

K4208高温合金中析出相的表征

K4208高温合金中W、Mo含量比较高,通常会形成碳化物和金属间相。为了对K4208高温合金中析出相做定性定量分析,通过实验选择了合适的电解条件:电解液为10g/L氯化锂-40g/L磺基水杨酸-5%(V/V)甘油甲醇溶液,电流密度为0.04~0.06A/cm²,电解温度为0~-5℃。采用电解萃取方法将析出相从合金基体中分离,研究了析出相的分离方法,将碳化物溶解,得到了单独新相。通过X射线衍射(XRD)测定了析出相的点阵常数,用X射线小角散射法测定析出相的粒度分布。采用扫描电镜(SEM)研究了析出相的形貌和元素组成,用电感耦合等离子体原子发射光谱法(ICP-AES)测定了析出相中各元素含量及析出相总量。结果表明:电解条件对析出相的萃取量影响明显,K4208高温合金中有新相、γ′、M₆C和M₁₂C这4种析出相。新相的稳定性比较高,不溶于6%(V/V)H₂SO₄-20%(V/V)H₂O₂溶液和20%(V/V)HCl乙醇溶液,在50%(V/V)H₂SO₄中部分溶解。M₆C和M₁₂C相呈块状,粒径相对较小,混合相的平均粒径为170.7nm;新相呈片状,颗粒粗大,平均粒径为216.6nm。     

K4208高温合金中析出相的表征

K4208高温合金中W、Mo含量比较高,通常会形成碳化物和金属间相。为了对K4208高温合金中析出相做定性定量分析,通过实验选择了合适的电解条件:电解液为10g/L氯化锂-40g/L磺基水杨酸-5%(V/V)甘油甲醇溶液,电流密度为0.04～0.06A/cm²,电解温度为0～-5℃。采用电解萃取方法将析出相从合金基体中分离,研究了析出相的分离方法,将碳化物溶解,得到了单独新相。通过X射线衍射(XRD)测定了析出相的点阵常数,用X射线小角散射法测定析出相的粒度分布。采用扫描电镜(SEM)研究了析出相的形貌和元素组成,用电感耦合等离子体原子发射光谱法(ICP-AES)测定了析出相中各元素含量及析出相总量。结果表明:电解条件对析出相的萃取量影响明显,K4208高温合金中有新相、γ′、M₆C和M₁₂C这4种析出相。新相的稳定性比较高,不溶于6%(V/V)H₂SO₄-20%(V/V)H₂O₂溶液和20%(V/V)HCl乙醇溶液,在50%(V/V...     

近平衡条件下LaFe13-x-ySixCoy合金凝固组织和相形成的研究

采用感应熔炼的方法研究了LaFe13-x-ySixCoy合金近平衡条件下的凝固行为.应用XRD和SEM扫描电镜分析了合金组织结构和相组成.结果表明:La(Fe,Co,Si)13相是包晶反应生成的.过冷度和添加Si、Co的含量对合金的凝固行为有很大影响;当过冷度△T≥40 K,x=1.5时合金凝固组织中出现La(Fe,Co,Si)13相.应用经典形核理论对此进行了解释.     

Synthesis and Properties of Eu Activated Strontium Molybdate Phosphor

In order to prepare fluorescent material for white Light Emitting Diodes （LEDs）, a new Eu^3＋ activated molybdate phosphor SrMoO4 was fabricated with solid-state method. X-ray diffraction （XRD） showed that the doping of trivalent europium ion reduced the lattice parameters. The excitation and emission spectra indicated that this phosphor could be excited effectively by the visible light, and then emitted red light with the peaks located at 616 and 624 nm. The influence of Eu^3＋ concentration on the luminescent properties of Eu^3＋ doped SrMoO4 was investigated and the 25% （mole fraction） was the appropriate molar concentration. The reaction time and temperature had obvious effect on the luminescent properties. The luminescent intensity reached the strongest when it was sintered at 800 ℃ for 3 h.     

机械化学对Na-MMT结构性质的影响

以钠基蒙脱土(Na-MMT)为研究对象,分别对其在分散介质空气、无水乙醇、N,N-二甲基甲酰胺(DMF)中进行球磨,再利用粒度分析(LPS)、X-射线衍射(XRD)、热重分析(TGA)、扫描电镜分析(SEM)等方法研究了不同分散介质中球磨对钠基蒙脱土结构性质的影响。     

片状纳米硅的结构及发光性能表征

采用精密磨削加工工艺法制备了厚度为纳米级片状硅,以FESEM,HRTEM,EDS,SEAD及XRD等分析手段对片状纳米硅的形貌、结构及组分进行分析和表征.结果表明,所制得的片状纳米硅为纳米级片状结构,片平均厚度为10～15nm,具有立方金刚石结构.由于量子限制效应的影响,所制得的片状纳米硅的拉曼光谱发生了红移.室温下在404,495及750 nm处可观察到片状纳米硅的紫、绿、红3种光致发光谱,解释了片状纳米硅的发光机制.     

钼粉物理性能对其压坯挠曲强度的影响

钼压坯的挠曲强度是衡量钼粉质量的重要指标之一。通过对钼粉的粒度分布、费氏粒度、松装密度、振实密度以及颗粒形貌等对钼压坯挠曲强度的影响研究,探讨其相互关系,有利于产品质量管理前置。研究结果表明,钼压坯的挠曲强度值的大小取决于钼粉的颗粒团聚状况和粒度分布;钼粉的松装密度和振实密度越大,钼粉中小颗粒聚集和颗粒熔融形成的"硬"团聚越少,粒度分布越接近标准正态分布,所得压坯的挠曲强度值则高。     

Physical Properties and Solidification Structure of Al－SiEutectic Alloy Melt with Cerium Modification

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Density and Activity Characterization of Activated Sludge Flocs

Activated sludge flocs are made up of a conglomerate of materials including microorganisms, exocellular polymers, inert particulates, slow and nonbiodegradable organic particles, and water. The goal of this study was to determine if inert/unbiodegradable aggregates had higher densities than active biomass. It was also desired to determine whether mixed liquor could be gravimetrically settled to differentially stratify flocs based on density and biological activity. In this manner, if activity stratification is possible, then less active biomass could be wasted preferentially during wastewater treatment operations (e.g., during daily wastage), thereby increasing the effective solids retention time and improving process performance. This paper reports the initial set of results, which focused on establishing density values of inert/unbiodegradable fractions of activated sludge floc, and the heterotrophic activity measurements of faster settling flocs compared to slower settling flocs. The results indicate that activated sludge from a local wastewater treatment plant had aggregate densities as low as 1.038?g/mL for slower settling floc particles and as high as 1.065?g/mL for faster settling floc particles. Primary effluent “inert+unbiodegradable particulate organic” fractions, which ultimately accumulate in mixed liquor and contribute to the inactive activated sludge floc fraction, had densities of approximately 1.24?g/mL. Mixed liquor that was digested in excess of 90 days to reduce any degradable organics revealed aggregate densities between 1.11 and 1.12?g/mL. Settling column experiments indicated that floc particles settled at rates ranging from less than 5?m/h to greater than 30?m/h. Specific oxygen uptake rates signified that the heterotrophic activity was homogeneous across all settling velocities except those flocs with a settling velocity of less than 5?m/h. These flocs exhibited a specific oxygen uptake rate of between 31 and 110% higher than the remaining floc. Determination of the mass fraction of these flocs indicates that they account for approximately 2% of the overall biomass. This low fraction limits the usefulness of differentially settling unaltered waste activated sludge to recover portions with higher activity.     

Influence of Cold Forming and Heat Treatment on the Microstructure and Mechanical Properties of an Air‐Hardening Steel

The use of air‐hardening steels in the manufacture of automobile body components shortens the corresponding process chain by means of eliminating the immersion or gas quenching operation since hardening occurs in still air. To choose the optimal forming and heat‐treatment parameters, the development of the microstructure needs to be considered as a consequence of the thermomechanical production processes. The object of this work is to investigate the effects of forming and the subsequent heat‐treating on the changes of the microstructural parameters for the air‐hardening steel LH800. For this purpose, specimens were processed under different forming and heat‐treating conditions and subsequently examined by means of SEM and mechanically tested using tensile tests. Based on this, an empirical equation was derived which describes the influence of both the martensite's bundle thickness and the original austenite's grain size on the yield stress. In this way, microstructural parameters can be identified which lead to good mechanical properties. The measured correlation can thus be used for modeling the LH800 steel's forming and heat‐treatment processes.