粉末注射成型氧化锆喂料的制备及成型研究

制备包含以石蜡(SW)、硬脂酸(SA)和高密度聚乙烯(HDPE)为主的黏结剂体系和氧化锆粉料的喂料,来研究氧化锆粉末的注射成型工艺.通过喂料的制备、注射成型、脱脂、烧结和一系列的测试,分析了黏结剂体系在混料过程中的分散情况和作用,确定了合适的热脱脂及烧结升温制度以及成型剂大量脱除的温度区间.在此系列实验中,发现在某一固含量时,混料的均匀性及成型性最佳,烧结后制品的烧结密度达到最高且表观良好,可获得高致密度的注射陶瓷制品.     

耐磨性金属基陶瓷涂层的制备及其高温抗氧化性能

以磷酸二氢铝黏结剂与陶瓷骨料(氧化铝,硅酸锆,氧化锆)结合,制备出高温抗氧化耐磨损的金属基陶瓷涂层.对影响涂层耐磨性能的因素进行了研究,实验得到最优的耐磨金属基陶瓷涂层工艺:硅酸锆微粉和骨料添加量分别为陶瓷涂层总质量的21%和35%,无机黏结剂中Al/P比在1.3∶3~1.4∶3之间,骨料粒度中粗颗粒所占质量比为40%.对最佳工艺下的金属基陶瓷涂层进行抗氧化性能研究,涂覆金属基陶瓷涂层的金属的氧化增量比未涂覆的金属的氧化增量降低74%,具有很强的抗氧化性能.     

成型压力对GZO陶瓷靶材无压烧结致密化的影响

采用模压成型-无压烧结法制备Ga掺杂量为3wt%的氧化锌陶瓷靶材(ZnO∶Ga2O3=97∶3wt%).分析研究了成型压力对靶材致密度、物相组成、微观结构及烧结收缩变化率的影响.采用X射线衍射仪分析物相组成,扫描电镜观测烧结体断口形貌,用热膨胀仪分析试样烧结收缩曲线,阿基米德排水法测量试样密度.结果表明:成型压力对GZO靶材烧结时生成ZnGa2O4的固相反应有促进作用,并且当成型压力由120MPa提高到200MPa时,固相反应生成更多的ZnGa2O4尖晶石相导致GZO陶瓷烧结致密所需的温度也有所提高.成型压力为200MPa时靶材致密度最高,相对密度达93.54%TD.     

复合涂层粉料制备莫来石陶瓷的工艺研究

莫来石陶瓷是一种具有优良特性的陶瓷 ,在结构、电子、光学领域具有广泛的应用前景。利用 TEOS的水解在亚微米级氧化铝颗粒表面涂上无定型 Si O2 ,制得莫来石前驱体——复合涂层粉料。并对制备莫来石瓷的成型工艺及制备参数进行了研究。采用 90 0 MPa干压成型 ,1 60 0℃保温 2 h常压烧结制备出直径 1 3mm烧成体 ,相对密度为 99.2 4 % ,几乎完全致密 ;根据 XRD衍射图谱 ,烧成体试样由纯莫来石相组成 ;根据 SEM分析 ,试样显微结构致密、均匀     

国际热核聚变实验堆朗缪尔探针用高纯氧化铝陶瓷的制备

针对国际热核聚变实验堆偏滤器朗缪尔探针的绝缘部件尺寸小、脆性高、机加工性能差等特点,以高纯超细氧化铝粉为原料,采用粉末注射成形工艺制备高纯氧化铝陶瓷管,并对其物相组成、微观组织、热学和电学性能进行表征和分析.结果表明,高纯氧化铝陶瓷管中氧化铝的质量分数达到99.99％,主晶相为α-氧化铝,晶粒规则,结构致密,具有优良的...     

氧化铝陶瓷光固化浆料的制备及脱脂工艺优化研究

本文重点研究了光固化浆料固含量和粘度的关系,通过分散剂调控流变学性能,实现了高固含量浆料(45 vol%)的制备并完成打印.在此基础上我们发现,脱脂烧结工艺是决定氧化铝陶瓷成型的另一关键因素.脱脂不彻底会导致气孔、裂纹等缺陷,直接影响到陶瓷质量.鉴于此,本研究针对所制备的氧化铝陶瓷浆料有机物类型,调整了脱脂曲线,并证实通过先在真空中热解后在空气中除碳的两步脱脂方式可使有机物充分去除,不易产生气孔,最终获得了结构致密的氧化铝陶瓷材料.本文系统总结了分散剂种类、浓度及氧化铝固含量对浆料粘度的影响,优化了脱脂工艺,为复杂结构陶瓷材料的光固化成型及性能的优化提供了实验依据.     

渗硅碳化硅材料的制备与性能研究

采用不同工艺制备渗硅碳化硅,分析了生坯密度、成型方法、颗粒级配等对制品结构及性能的影响.结果表明:恰当的生坯结构及合理的成型方法、烧成制度,是制备结构致密均匀、气孔率低、密度及强度高的渗硅碳化硅材料的关键.     

软锰矿浆脱硫尾渣用作免烧砖试验研究

利用河池地区软锰矿浆脱硫尾渣生产新型建筑材料免烧砖,探索制作尾渣免烧砖的配料比、成型压力以及养护时间等影响免烧砖性能的最佳工艺条件.实验结果表明:高达95%的软锰矿浆脱硫尾渣粒度粒径在80μm以下,颗粒较细,是较好的制备非烧结砖的材料."软锰矿浆烟气脱硫副产尾渣—水泥胶凝材料—水"体系是较好的配料方案.在配料比等其他工艺条件相同的情况下,抗折与抗压强度的大小随着成型压力的增大而增大.随着黏结剂添加量的增加,免烧砖试样的抗折与抗压强度得以增加;当黏结剂添加量增加到一定程度时,抗折与抗压强度反而降低.综合以上因素得出免烧砖制品的最佳工艺参数是:脱硫尾渣∶胶凝材料=5∶1,成型压力为20 MPa;含水率为10%,自然养护时间控制为7~28 d.     

热压工艺对声屏障用非织造板材隔音性能的影响

以细旦中空涤纶和低熔点涤纶为原料,采用混合针刺并结合热压工艺制备声屏障用非织造隔音板材.通过正交试验法对声屏障用非织造板材的热压成型工艺参数进行研究,探讨了纤维质量配比、成型温度、成型时间等工艺参数对声屏障用非织造板材隔音性能的影响.实验结果表明,当m(中空涤纶)∶m(低熔点涤纶)=50∶50、成型温度为165℃、成型时间为30 s时,所制备的声屏障用非织造板材的隔音性能最佳.     

凝胶注模制备氧化锆管工艺研究

采用凝胶注模成型工艺制备薄壁大长径比的氧化锆管,研究分散剂种类和用量及固相体积分数对浆料黏度的影响,以及成型和烧结条件对氧化锆管生坯和氧化锆陶瓷管质量的影响。结果表明,选用阴离子聚丙烯酰胺作为分散剂对浆料的降黏效果较好,当其含量为0.25‰时,能够显著降低浆料黏度;当浆料的固相体积分数为54%,成型后的坯体在60℃下保温3h烘干,可制备出结构均匀、精度较高的氧化锆管生坯,其在1550℃下烧结成瓷后密度高达5.99g/cm3。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the