均匀共沉淀法合成纳米Gd2O3：Eu粉体及其发光特性

以六次甲基四胺（hexamethylenetetramine,（CH2）6N4,HMT）为沉淀剂,在GdCl3和EuCl3混合溶液中,利用均匀共沉淀法制得了纳米颗粒.结果表明,获得的Gd2O3：Eu纳米颗粒近似为球形,尺寸均匀,平均粒径为100 nm,且每个球形颗粒由平均粒径为20 nm的微晶聚并而成.Gd2O3：Eu荧光粉在波长612 nm的红光发射来自Eu^3＋的5D0-7F2电偶极跃迁,发光强度随煅烧温度提高而增强,随Eu^3＋掺杂摩尔分数的提高而增强.Eu^3＋掺杂摩尔分数超过7%时,发生浓度淬灭,发光强度减弱.     

氰化尾渣高温氯化焙烧制备陶粒

以氰化尾渣为主要原料,配以膨润土、钠长石、CaCl2、煤粉等辅料,利用高温氯化焙烧方法制备了陶粒。采用XRD、SEM、XRF、TG/DTA、ICP-OES等研究了氰化尾渣的物相成分、微观结构等理化性能,测定了陶粒成品的吸水率、堆积密度、重金属挥发率等,并对烧成效果最好的陶粒成品进行了微观结构分析。结果表明,氰化尾渣利用率最高能达到75%,得到的焙烧陶粒1h吸水率为9.45%、堆积密度为642.93kg/m3,Au、Ag、Cu、Pb、Zn等金属挥发率分别达到83.02%、65.31%、75.89%、90.65%、85.34%。     

新筛选菌种Delftia sp.XYJ5生物降解苯胺的途径

A promising gram-negative bacterial strain for the biodegradation of aniline as the sole carbon, nitrogen and energy sources was successfully isolated and identified as Delftia sp. XYJ6. The optimal temperature and pH for both the growth of Delftia sp. XYJ6 and the biodegradation of aniline were 30°C and 7.0, respectively. Initial aniline of 2000 mg•L－1 could be completely removed by the strain at 22 h, which showed that Delftia sp. XYJ6 had a strong ability in the biodegradation of aniline. It indicated that aniline was firstly converted to catechol catalyzed by aniline dioxygenase as a first product, which was then further biodegraded to cis,cis-muconic acid catalyzed by the catechol 1,2-dioxygenase of Delftia sp. XYJ6 as a second product. Cis,cis-muconic acid could also be further biodegraded to other small compound again. The pathway for the biodegradation of aniline by Delftia sp. XYJ6 was not previously reported.     

游离静止细胞中腈水合酶的失活动力学

Nitrile hydratase (NHase) is an important industrial enzyme used for acrylamide production from acrylonitrile. The deactivation kinetics of NHases in free resting cells of Rhodococcus sp. was presented based on a bi-steady state assumption. Effects of hydration temperature, product concentration and substrate concentration on NHase deactivation were investigated experimentally and correlated with a first order deactivation kinetics. The results showed that the hydration temperature and product concentration were major factors governing the deactivation of NHases under substrate-feeding conditions. When acrylamide concentration was higher than 250 g•L－1, the deactivation of NHases became serious and the bi-steady state assumption was not applicable. When the hydration temperature was controlled at a relatively higher level such as 28°C, the total deactivation rate constant was about 2.8-fold of that at 20°C.     

金属多孔材料孔结构表征技术

孔结构是影响金属多孔材料本征特性与使用效果的关键因素之一.孔结构分解为孔形状、孔弯曲与粗糙度、孔隙度、孔径、比表面积等几个方面,介绍了常用的表征技术和国内外测量仪器的发展状况及技术参数,并分析了表征技术中存在的问题.     

Al2O3／20％Ni网状复合材料抗热震性研究

采用热压方法制备了Al2O3／20％Ni网状复合材料,通过压痕一淬火法在、300—900℃淬火温差范围内评估了热震抗力．结果表明．复合材料的抗热震性明显高于单相Al2O3陶瓷．根据材料的力学和物理性能．计算了Al2O3陶瓷和Al2O3／20％Ni网状复合材料的抗热震因子R′和R″″,结果表明．复合材料的抗热震因子亦大于单相Al2O3陶瓷,与热震实验结果相吻合．     

RS-Si_3N_4/SiC复相耐火材料的组织与性能

利用三点弯曲试验 ,RXD,SEM等手段研究了原料组成对 RS-Si3N4 /Si C复相耐火材料的密度、抗折强度、抗热震能力以及相组成、显微组织和断口形貌的影响 .结果表明 ,当原料中硅质量分数为 2 5%时 ,Si3N4 /Si C复相耐火材料具有最高的抗折强度和抗热震稳定性 .论文中对此种材料的相结构、显微组织和断口形貌进行了分析     

Al_2O_3/TiB_2复合材料组织与性能的研究

利用金相显微镜、 SEM、抗折试验机和硬度计研究了无压烧结 Al2 O3/ Ti B2 陶瓷复合材料的组织与性能 .结果表明 ,利用无压烧结技术可以制备这种性能优良的新型材料 ,Ti B2 细化材料的晶粒 ,提高了材料的机械牲能 ,文中还对这种材料的氧化性能进行了研究     

TiB2含量对B4C-TiB2-Al复合材料组织与力学性能的影响

通过在B4C-TiB2预烧体中真空熔渗Al制备了B4C-TiB2-Al复合材料,研究了TiB2含量对复合材料显微组织和力学性能的影响.结果表明: B4C-TiB2-Al复合材料主要由B4C,TiB2,Al和Al3BC等相组成;随着TiB2含量的增加,复合材料的HRA硬度逐渐降低,抗弯强度逐渐增大,断裂韧性先增大后稍微降低,当TiB2含量为40%(质量分数)时,复合材料的气孔率、硬度HRA、抗弯强度和断裂韧性分别为1.32%,80.3,559.4 MPa和7.83 MPa·m1/2;延性Al的加入,裂纹的偏转和分叉、B4C和TiB2晶粒的细化以及B4C基体和TiB2晶粒热膨胀的不匹配,是造成材料断裂韧性提高的主要原因;随着Al渗入量的增加,复合材料断口中金属撕裂棱及韧窝的比例增加.     

超疏水膜的研究进展

近年来,由于超疏水膜表面在自清洁、微流体系统和特殊分离等方面的潜在应用,超疏水性膜的研究引起了极大的关注.本文着重讨论了超疏水膜的化学组成及物理结构、制备方法,并对超疏水膜的发展方向进行了展望.