氧化锆基固体电解质老化性能的研究

ZrO2陶瓷器件在700℃下退火处理1000h，研究了ZrO2基固体电解质的老化性能。结果表明：在700℃退火处理1000h后，8YSZ、8YbSZ和4Yb-8YSZ的电导率分别下降39%、49%和10%。比较8YSZ、4Yb-8YSZ和8YbSZ三种材料表明，在8YSZ二元系统中掺杂Yb2O3可改善ZrO2固体电解质材料的老化性能。     

前牙IPS热压铸造全瓷粘接桥修复的3年临床应用研究

目的:观察单个上前牙或下颌2个以内前牙缺失采用IPS Empress 2或IPS e.max热压铸造全瓷粘接桥的临床修复效果.方法:22位患者,共制作26件前牙热压铸造全瓷粘接桥,包括16例单翼全瓷粘接桥和10例双翼全瓷粘接桥,修复后3个月、6个月、1年,2年和3年观察修复体的完整性,基牙的继发龋,边缘着色及修复体的颜色匹配.结果:1例双翼全瓷粘接桥修复后3个月脱落;1例双翼全瓷粘接桥6个月后一侧连接体折断,均改为单翼全瓷粘接桥后继续使用;1例双翼全瓷粘接桥修复后2年脱落,修复体完整,重新粘接后继续使用,没有继发龋和边缘着色,颜色与邻牙相协调.整体修复成功率为88.5%.结论:对于2个以内前牙缺失的患者,采用IPS热压铸造全瓷粘接桥可以取得较好的临床修复效果.     

沥青老化及RAP料的评价

沥青混合料再生利用技术,是将需要翻修或者废弃的旧沥青混合料,经过翻挖、回收、破碎、筛分,再和新集料、新沥青材料适当配合,重新拌合,形成具有一定路用性能的再生沥青混合料,用于路面坑槽修补、铺筑路面面层或基层的整套工艺技术.在这个变化中,沥青老化是一个重要的方面,其次是对RAP料的性能评价,本文通过对沥青老化和RAP料的分析评价,以数据说明这一变化中的相关指标的变化.     

钛酸锶压敏陶瓷及其性能影响因素

为了提高SrTi03压敏陶瓷的性能，对其影响性能的因素进行了论述，指出主要影响因素是配方体系及制造工艺中的绕结工艺，并指出改善SrTi03综合性能的途径是进一步提高瓷料配方的适应能力并完善制造工艺。     

固体氧化物燃料电池的中低温化研究

中低温固体氧化物燃料电池(IT—SOFC)是目前固体氧化物燃料电池研究的热点和发展的趋势。对中低温固体氧化物燃料电池的研究现状进行了综述，重点对降低SOFC操作温度主要途径，如电解质薄膜化、新型高电导率电解质材料和高性能电极的研究等几方面进行了论述。     

氧化铟纳米粉的低温制备

本文探讨了一种ITO纳米粉的低温、易于量产的制备方法。将铟锡氢氧化物置于充满氩气的高压釜内,在300℃、2MPa的条件下就可制得ITO的纳米颗粒。用XRD、透射电镜分析ITO纳米颗粒的形貌和粒径以及结晶状况。与其他方法进行对比,本方法反应条件更加柔和,且可以达到量产,有利于推广应用。     

低温烧结技术研究

本介绍了在酒钢原料条件下,低温烧结试验室试验情况。烧结杯试验结果表明：燃料降低10－15％,采用强化制粒、提高料层等措施,可使利用系数与基准期基本持平,同时烧结矿FeO含量降低2－3个百分点。     

全精矿低温烧结最佳工艺制度的研究

本文主要介绍三个烧结工艺参数──料层高度、燃料配比、烧结负压对烧结生产率、烧结矿质量、燃料消耗影响的试验研究结果。结果表明：全磁精矿低温烧结可以获得高产、优质、低耗的技术经济指标；低碳高料层操作是实现低温烧结的必要手段；烧结矿中ＰｅＯ含量对其还原性的不利影响较小．并得到了最佳烧结工艺参数。     

烧结矿低温还原粉化影响因素研究进展

烧结矿入炉后,会在高炉上部发生低温还原粉化现象,严重时会影响高炉料柱透气性,破坏高炉顺行.为了改善烧结矿的这一性能,揭示烧结矿粉化机制,归纳了化学成分、添加物、微观结构、外部还原气氛和烧结工艺等对烧结矿低温还原粉化的影响,分析了改善烧结矿低温还原粉化性能的方法,为粉化机制研究、烧结配矿提供参考.     

表面改性对氧化锆陶瓷注射成形的影响

采用改性剂对ZrO2粉末进行表面改性处理制备出了有机/无机包覆的氧化锆陶瓷粉末.用红外光谱表征了粉末颗粒表面官能团的变化,讨论了表面改性对粉末的极性、粒度、安息角、松装密度和振实密度以及对注射成形工艺的影响.研究结果表明:改性剂分子与粉末颗粒表面吸附的羟基发生了Lewis酸碱反应,并形成了包覆吸附;通过表面改性,粉末由极性粉末变为非极性粉末,在环己烷溶液中的粒度由4.88μm减小到0.64μm,团聚系数由41降到5,团聚明显降低,粉末安息角由68°降低到45°,松装密度由0.8g/cm3增加到1.32g/cm3,振实密度由1.45g/cm3增加到2.52g/cm3;表面改性降低了氧化锆注射料的粘度、混料温度、注射温度和注射压力,改善了成形性,装载量从53%提高到58%.     

影响烧结矿低温还原粉化指数因素的定量分析

借助计量经济学软件Economical VIEW 7对烧结矿化学成分对低温还原粉化指数的影响进行了定量分析,得出了烧结矿不同化学成分与RDI+3.15之间的线性关系,其中R2和Ti O2是影响RDI+3.15的主要因素。将实验结果用于实际生产,得出的结果与预测结果基本吻合。     

水溶性环氧树脂的氧化锆陶瓷凝胶注模成型

用分散剂聚丙烯酸铵(NH4PAA)和海因环氧树脂与ZrO_2粉末以及去离子水混合成ZrO_2陶瓷浆料,采用凝胶注模法制备ZrO_2陶瓷坯体,在1 500℃无压烧结后获得ZrO_2陶瓷材料,研究浆料的流变性能,并分析分散剂加入量、固相含量和烧结温度对凝胶注模ZrO_2陶瓷生坯和烧结体组织与性能的影响。结果表明,当分散剂(NH4PAA)和海因环氧树脂的添加量(均为质量分数)分别为0.8%和8%,固相ZrO_2的体积分数为50%时,获得黏度为0.46 Pa/s的适合浇注的ZrO_2陶瓷浆料,所得的陶瓷生坯表面光洁、不起皮、不开裂,强度达61.05 MPa,经过1 500℃烧结后的ZrO_2陶瓷抗弯强度为672.52MPa,相对密度达98.26%,其结构均匀、致密性好,以四方相t-ZrO_2为主。     

高还原势气氛下烧结矿低温还原粉化试验研究

在高还原势气氛下进行烧结矿的低温还原粉化试验,考察RDI＋6.3、RDI＋3.15和RDI-0.5的变化情况,分析不同还原气氛对烧结矿低温还原粉化的影响规律,探究烧结矿在氧气高炉上部的粉化行为.结果表明：烧结矿在氧气高炉气氛下的低温还原粉化率高于在传统高炉气氛下的低温还原粉化率,但其RDI＋3.15仍高达82.7%;随着还原气氛中CO和H2含量的提高,烧结矿的低温还原粉化率明显上升.     

Bonding to zirconia ceramic: adhesion methods and their durability

Sulfur mustard (SM) induces vesication via poorly understood pathways. The blisters that are formed result primarily from the detachment of the epidermis from the dermis at the level of the basement membrane. In addition, there is toxicity to the basal cells, although no careful study has been performed to determine the precise mode of cell death biochemically. We describe here two potential mechanisms by which SM causes basal cell death and detachment: namely, induction of terminal differentiation and apoptosis. In the presence of 100 microM SM, terminal differentiation was rapidly induced in primary human keratinocytes that included the expression of the differentiation-specific markers K1 and K10 and the cross-linking of the cornified envelope precursor protein involucrin. The expression of the attachment protein, fibronectin, was also reduced in a time- and dose-dependent fashion. Features common to both differentiation and apoptosis were also induced in 100 microM SM, including the rapid induction of p53 and the reduction of Bcl-2. At higher concentrations of SM (i.e., 300 microM), formation of the characteristic nucleosome-sized DNA ladders, TUNEL-positive staining of cells, activation of the cysteine protease caspase-3/apopain, and cleavage of the death substrate poly(ADP-ribose) polymerase, were observed both in vivo and in vitro. Both the differentiation and the apoptotic processes appeared to be calmodulin dependent, because the calmodulin inhibitor W-7 blocked the expression of the differentiation-specific markers, as well as the apoptotic response, in a concentration-dependent fashion. In addition, the intracellular Ca2+ chelator, BAPTA-AM, blocked the differentiation response and attenuated the apoptotic response. These results suggest a strategy for designing inhibitors of SM vesication via the Ca2+-calmodulin or caspase-3/PARP pathway.     

Wetting and brazing zirconia ceramic with alloys of the CuGaTi system

Experiments on the wetting of zirconia ceramics by CuGaTi alloys have been carried out. A method was developed for brazing by capillary infiltration of a layer of titanium powder with CuGa alloy. Specimens of brazed joints were prepared and their shear strength was measured. That strength reached 620 MPa, the average hardness being about 380 MPa. Institute for Problems of Materials Science, Ukraine National Academy of Sciences, Kiev. Translated from Poroshkovaye Metallurgiya, Nos. 7–8(408), pp. 52–54, July–August, 1999.     

Study of mechanism of cleavage fracture at low temperature

In this investigation, a series of crack opening displacement (COD) tests were carried out at several low temperatures for C-Mn weld steel. Some of the specimens were loaded until fracture, and the mechanical properties and microscopic parameters on fracture surfaces were measured. Other specimens were unloaded before fracture at different applied loads. The distributions of the elongated cavities and the cleavage microcracks ahead of fatigue crack tips were observed in detail. Based on the experimental results, the combined criterion of a critical strainε _p ≥ ε_c) for initiating a crack nucleus, a critical stress triaxiality(σ _m/σ ≥ t_c) for preventing it from blunting, and a critical normal stress(σ _yy/σ_f) for the cleavage extension was proposed again, and the critical values of ε_p and σ_m/−σ for the C-Mn weld steel were measured. The reason why the minimum COD value could not be zero is explained. The mechanism of generation of the lower limit COD value on the lower shelf of the toughness transition curve is proposed.     

钒钛磁铁精矿球团低温焙烧参数研究

针对米易球团厂链篦机-回转窑球团生产线投产初期焙烧温度偏高带来的一系列问题,研究了预热温度、球团粒径、氧化气氛对钒钛磁铁精矿球团氧化率的影响。通过提高球团粒度均匀性、改造干燥鼓风机、优化热工制度,使焙烧温度从1 300℃下降到1 150℃,实现了钒钛磁铁精矿球团的低温焙烧。     

Evaluation of temperature effects on selectivity in RPLC separations using polybutadiene-coated zirconia

The effect of temperature on selectivity in RPLC method development has been evaluated on polybutadiene-coated zirconia. We find that the influence of temperature on selectivity depends strongly on solute type. For solutes of similar structure such as polyaromatic hydrocarbons, temperature has almost no effect on selectivity; however, for solutes with very different functional groups such as chlorophenols, temperature changes did significantly affect selectivity. We feel that simple mixtures with one dominant retention mechanism-e.g., solvophobic retention-will not be helped appreciably by adjusting temperature. However, in complex mixtures with polar and ionizable solutes, optimization by varying the temperature may well be fruitful.