氧化锌分散液的制备及机理研究

采用超声解团聚法制备氧化锌分散液,探讨了体系pH对氧化锌分散液的影响,考察了分散剂聚丙烯酸(PAA)用量和超声时间对氧化锌分散液稳定性的作用规律,重点阐述了超声解团聚法形成氧化锌分散液的机理。研究表明:当pH=7、PAA用量1.5%、超声分散时间120min时,氧化锌分散液的分散性和稳定性最好。超声解团聚法制备分散液过程中,经历了润湿、超声解团聚分散、超声后分散液稳定三个阶段,氧化锌粉体会生成较小团聚体,加入分散剂PAA不仅可以提高分散效率,同时可以起到稳定新生成较小团聚体的作用。     

大尺寸单针状氧化锌晶体的制备及生长机理

用气相法制备ZnO晶体,得到了具有大尺寸的晶体结构和规则外形的单针状ZnO,最长长度25mm,直径0.8 mm。讨论了不同的空气流量、载流N2流量、锌挥发温度、反应温度生长条件下对ZnO晶体生长结果的影响,并对生长机理做了初步探讨。     

四针状氧化锌晶须的研究进展

四针状氧化锌晶须是唯一具有三维空间结构的晶须。作为复合材料的一种特殊组份,它不仅显著地提高了材料的力学性能,而且赋予材料导电、吸波、光电等特殊的物理性能,使之成为有特殊功能的复合材料。本文综述四针状氧化锌晶须的制备,侧重讨论其生长机理方面的研究进展,并指出了存在的问题和进一步研究的方向。     

氧化锌球团还原的机理研究

采用等温法研究了纯氧化锌配加石墨碳粉制成含碳氧化锌球团的还原动力学 ;考察了坩埚尺寸对氧化锌还原的影响 ;并研究了铝浴条件下对含碳或不含碳氧化锌球团还原的影响。结果表明 :根据Arrhenius方程计算出 ,当碳气化反应和界面还原反应为限制环节时 ,在 12 73～ 14 2 3K下其活化能分别为 3 7 615kJ/moL和 43 192kJ/moL ,碳还原氧化锌的还原速度由气相扩散所控制 ,12 73～ 14 2 3K下其活化能为 46 5 48～ 5 3 2 80kJ/moL ,含碳球团在大坩埚中的还原速度快 ,有铝浴存在的还原速度快 ;在 12 73～ 15 2 3K下铝浴与氧化锌球团 (不含碳 )基本不发生还原反应     

压强对射频溅射氧化锌薄膜结构和性能的影响

采用射频溅射方法在聚脂(PET)胶片上沉积ZnO：A1薄膜，实验结果表明沉积压强对氧化锌透明导电薄膜的表面形貌、结构、光电性能等有较大的影响，在低的沉积压强下薄膜具有很好的(002)结构，有优良的光、电综合性能。同时详细讨论了影响结构和性能的诸因素。     

黄铜熔炼炉环形吸尘罩对氧化锌生成的影响

西安重型机器研究所为我厂设计的黄铜炉除尘设备从整体上来说是成功的,铸造车间常见的那种乌烟彰气和氧化锌像雪花一样四处飘扬的现象不复存在。特别是启动30KW的风机时,工人们感觉良好,因为这时既无氧化锌尘呛人,又无热气炙人。但是,当打开炉盖时,人们看到一股明显的夹带着氧化锌白烟的热气流被环形罩抽走。每天除尘斗收集的氧化锌多达100多公斤,每     

铅炉渣成分对副产氧化锌品位的影响

理论分析了烟化法处理铅鼓风炉渣时，炉渣中的Pb、ZnO、FeO、SiOz和CaO对副产氧化锌品位的影响，并以生产实践中的数据加以验证。     

非团聚二钼酸铵热分解机理及热力学分析

通过DSC-TGA研究了非团聚二钼酸铵在室温至800℃温度范围内的热分解过程。结果表明：非团聚二钼酸铵在室温至800℃温度范围内的失重过程包含了4个连续阶段,各阶段反应温度区间为196.79～206.63℃、227.55～235.15℃、278.06～305.68℃和735.97～800℃。经分析,非团聚热分解实际只包括前3阶段,第4阶段的失重是由于前3阶段热分解产物的升华而引起的。XRD和SEM表征显示：非团聚二钼酸铵热分解产物为纯相MoO₃,其形貌遗传了母体二钼酸铵的形貌,并对MoO₃形貌的形成机理进行了探讨。提出了非团聚二钼酸铵的热分解机理并进行理论验证,在热分解的前3个阶段均失去摩尔比为2∶1的NH₃和H₂O。通过各阶段的热反应焓变值,计算了实验室条件下非团聚二钼酸铵及热分解中间产物(NH₄)₂Mo₃O₁₀(s)、(NH₄)₄Mo₈O     

四针状氧化锌晶须生长机理研究

根据ZnO的晶体结构和研究试验观察得到的正四面体晶核,认为T-ZnOw是在以立方闪锌矿结构的正四面体晶核基础上,于其四个角上结晶出六方纤锌矿晶体,该晶体进一步结晶、长大,包裹原有晶核,最终形成T-ZnOw。     

铅炉渣成分对副产氧化锌品位的影响

理论分析了烟化法处理铅鼓风炉渣时,炉渣中的Pb、ZnO、FeO、SiO2和CaO对副产氧化锌品位的影响,并以生产实践中的数据加以验证。     

The influence of water vapor on the decomposition of carbon monoxide on reduced iron oxide

Sintered, fine-grained ferric oxide (Fe₂O₃) with a porosity of 11.4 pct was used as a solid material in the present investigation of the rate of carbon monoxide decomposition in the presence of water vapor at temperatures of 430, 475, 513, 550 and 590‡C. It was found that small additions of H₂O markedly enhance the rate of carbon deposition and that there is an optimum content of H₂O in CO-H₂O mixtures which provides the maximum rate of carbon deposition at each temperature. According to SEM observations of the reaction products, water vapor affects significantly not only the rate of the process but also the structure of the carbon deposited. For , filamentary carbon is formed predominantly while at low values of the formation of flake carbon is favored. The results obtained have been explained with a suggestion on the possible formation of an intermediate complex [CHO]* on the catalytical surface.     

Growth mechanism for zinc coatings deposited by vacuum thermal evaporation

The vacuum thermal evaporation technique was used to simultaneously deposit zinc coatings onto interstitial free steel plates and single-crystal silicon wafers ...     

Kinetics of the solid state reaction between zinc oxide and aluminum oxide

A generalized expression of the rate constant for solid state reactions between metallic oxides has been presented in terms of ionic transport coefficients, taking into account the interactions with electrons. The rate constant of formation of ZnAl₂O₄ spinel from ZnO and A1₂O₃ was measured to bek = 97.4 exp [-360,600(J/mol)/RT] (mol ⋅ m^-1 ⋅ s^-1) (1503 to 1953 K). This experimental result was compared to the rate constant calculated from the tracer diffusivity of zinc, the electrical conductivity, and the transference number of zinc in the spinel. The calculated constant agrees with the measured value supporting the validity of the general expression for the formation of zinc aluminate spinel.     

The influence of dietary iron on zinc in rat

Cortical bone remodeling rates for rib samples from three archaeological populations and a modern autopsy sample were determined using an algorithm developed by Frost (Frost [1987a] Calcif. Tissue Res. 3:211-237). When plotted against the relative antiquities for population samples, histomorphometric variables; i.e., activation frequency (mu rc), net bone formation (netVf,r,t), and mean annual bone formation rate (Vf,r,t), exhibit a concordant trend of increased cortical bone remodeling activity levels over time. Two intensive foraging populations, Windover and Gibson, are similar for all bone remodeling parameters and have the lowest remodeling activity levels among the samples. The more recent Ledders sample, which is reported to practice agricultural subsistence, is consistently intermediate between these and a modern autopsy sample. Although there appear to be differences in bone formation rates among the populations it is concluded that these differences cannot be attributed to differences in bone remodeling rates among the populations, but rather are reflecting different effective ages of adult compacta for their ribs. These findings suggest that the earlier populations, particularly Windsor and Gibson, appear to have reached skeletal maturity at an older age than observed for modern.     

硫酸浸出处理铜锌废渣生产氧化锌

用硫酸浸出——置换——净化法分离回收铜锌废渣中的铜锌,产出海绵铜和氧化锌。铜、锌的漫出率分别达到98．99％和99．50％,铜、锌的回收率均达97％以上。工艺条件较易控制,产品海绵铜品位大于75％,氧化锌达到二级标准。     

X射线衍射标准曲线法测定氧化锌富集物中游离态氧化锌

氧化锌富集物的进口能弥补我国锌矿资源的不足,但要求其游离态ZnO不小于50%。目前常采用YS/T 1171.10—2017(Na₂EDTA滴定法)测定氧化锌富集物中ZnO含量,该方法测定过程冗长繁琐,测定1个样品需要2 d时间,已不能满足大批量氧化锌富集物进口快速通关的需要。故实验建立了采用X射线衍射(XRD)标准曲线法测定氧化锌富集物中游离态ZnO的方法。采用YS/T 1171.10—2017对进口氧化锌富集物样品进行定值,然后选取15个ZnO含量具有梯度的样品作为校准样品,选用ZnO最强衍射线(101)作为测量谱线,建立起积分强度对ZnO含量的标准曲线,曲线呈现较好的线性。采用标准曲线法、全谱图拟合法、化学方法分别测定了3个进口氧化锌富集物中ZnO含量,标准曲线法测定值与化学方法测定值一致,全谱图拟合法测定值与化学方法测定值偏差较大。实验方法测定1个样品仅需26 min,能够满足大批量氧化锌富集物进口快速通关的检测需求。