低温燃烧法合成Ce1-xNdxO2-x/2（0≤x≤0．6）纳米粉体

采用低温燃烧合成法，在柠檬酸-硝酸盐体系中合成出Ce1-xNdxO2-x/2（0≤x≤0．6）固溶体纳米粉体。X射线衍射（XRD）结果表明，Nd^3＋取代Ce^4＋进入晶格内部，形成具有单相立方萤石结构的固溶体，其晶格常数随Nd^3＋掺杂浓度的增大而线性增加，晶粒尺寸在15-24nm之间。透射电镜（TEM）结果表明，粉体颗粒尺寸在20-40nm之间，分散性较好，具有较高的烧结活性。拉曼光谱（Raman Spectrum）结果表明，F2g宽化峰的出现与掺杂后固溶体中产生的氧空位有关，并且随着掺杂浓度的增加，氧空位数量也再增加。     

氧化铝陶瓷管壳低成本微晶化的研究

国内生产的氧化铝管壳由于采用氧化铝粗粉为原料，产品的晶粒粗大、机械强度较低、加工量较大、烧成温度偏高、成品率低．提高国产氧化铝管壳的质量和档次的关键是低成本使氧化铝陶瓷管壳微晶化．采用自制的亚微米(平均粒径＜1μm)无硬团聚氧化铝粉，Al2O3含量为97．59％，减少高温出现的液相量及低温快烧工艺(1600℃，保温1h)，制备的微晶氧化铝管壳，其陶瓷品粒的平均粒径为6μm，品粒分布比较均匀，加工量远远低于国产粗晶粒氧化铝管壳．     

蒸汽爆炸粗混合阶段冷液中高温球传热阻力耦合特性的实验研究

采用蒸发电力模型,设计了高温颗粒同水相互作用的实验装置,进行了一系列单个,多个粒子在不同温度,不同入水初速度和不同冷液过冷度情况下的系列阻力实验,初步实验分析表明,高温颗粒在刚刚穿过冷液表面的下沉速度明显低于冷态颗粒的速度,实验值与蒸发曳力模型计算值符合较好.     

Analysis of DWTT property of thick X70 pipeline steel

The microstructures of X70 pipeline steels with different thickness specifications and different rolling reduction ratios were analyzed by metallographic microscope, scanning electron microscope, and electron backscatter diffraction techniques, and the original austenite microstructures were compared. The effect of compression ratio on the original austenite structure was studied. The results show that the large compression ratio in the rolling process is more conducive to refine austenite grains and improve the low- temperature toughness of thick X70 pipeline steel. However, due to the fact that the temperature during the finish rolling process is too low to permeate the center of the deformation, it is necessary to further use the low- temperature stage of the rough rolling process to perform deformation infiltration. Ultra- rapid cold cooling after rolling can improve the DWTT performance of the steel, but it is not sufficient to compensate for the fluctuation of DWTT performance caused by insufficient early austenite grain refinement.     

Correlation between Primary and Secondary Recrystallization Texture Components in Low-temperature Reheated Grain-oriented Silicon Steel

Low-temperature slab-reheated grain-oriented silicon steel is characterized by a sharp{411}148 primary recrystallization texture.To date,the influence of this texture on secondary recrystallization is not clear.Microtextures in primary and secondary recrystallized sheets of low-temperature reheated grain-oriented silicon steel were examined using electron backscatter diffraction.By comparing the textures and microstructures of specific primary recrystallized grains neighboring secondary grains with those of other primary grains,the influences of primary recrystallization textures and microstructures on the orientations of secondary grains were investigated.Results show that for low-temperature reheated grain-oriented silicon steel,the primary recrystallization sheet comprises {411}148,{111}112,and{001}120 texture components.During secondary recrystallization,the{111}112 primary recrystallized grains were easily consumed by abnormally grown Goss,deviated Goss,Brass,or{210}001grains;the{411}148 primary recrystallized grains were more resistant to being swallowed;and the{001}120grains were the most resistant to being consumed.For a particular primary grain,the distribution of its surrounding grain boundaries determined how easily it is consumed during secondary recrystallization.Primary grains surrounded by 20°-45°grain boundaries were consumed much earlier than those having grain boundaries above 45°,which is in accordance with high-energy grain boundary theory.In addition,special Σ9 boundaries between {411}148 and Goss grains move more slowly than Σ9 boundaries between{111}112and Goss grains,which is attributed to the different positions of110 rotation axis with respect to the normals of grain boundaries.     

Effect of transition metal doping on the sintering and electrochemical properties of GDC buffer layer in SOFCs

A dense Ce_0.9Gd_0.1O_2−d (GDC) interlayer is an essential component of the SOFCs to inhibit interfacial elemental diffusion between zirconia-based electrolytes (eg YSZ) and cathodes. However, the characteristic high sintering temperature of GDC (>1400°C) makes it challenging to fabricate an effective highly dense interlayer owing to the formation of more resistive (Zr,Ce)O₂ interfacial solid solutions with YSZ at those temperatures. To fabricate a useful GDC interlayer, we studied the influence of transition metal (TM) (Co, Cu, Fe, Mn, & Zn) doping on the sintering and electrochemical properties of GDC. Dilatometry data showed dramatic drops in the necking and final sintering temperatures for the TM-doped GDCs, improving the densification of the GDC in the order of Fe > Co > Mn > Cu > Zn. However, the electrochemical impedance data showed that among various transition metal dopants, Mn doping resulted in the best electrochemical properties. Anode supported SOFCs with Mn-doped, nano, and commercial-micron GDC interlayers were compared with regard to their performance and stability levels. Although all of the SOFCs showed stable performance, the SOFC with the Mn-doped GDC interlayer showed the highest power density of 1.14 W cm⁻² at 750°C. Hence, Mn-doped GDC is suggested for application as an effective diffusion barrier layer in SOFCs.     

脱硝还原剂尿素法改造常见问题及优化探讨

近几年,脱硝还原剂尿素法改造常见于火电厂,这是为了消除液氨这一危险源。但在改造设计中,有些具体问题容易被设计人员忽视。以L公司为例,尿素制氨系统运行2 a多来,暴露出了卸料管振动大、溶解罐溢流管出气泡、疏水箱振动大、疏水母管无法隔离、气相阀门腐蚀内漏、水解器排污时间定值不合理等一系列问题。经过L公司技术人员的努力,现已对部分问题进行了优化,经过运行,检验效果良好。     

CFB锅炉SNCR脱硝技术常见问题及对策

为降低火电燃煤机组烟气NO_x排放,介绍了循环流化床(Circulating Fluidized bed,简称CFB)锅炉选择性非催化还原法(Selective Non-Catalytic Reduction,简称SNCR)脱硝系统原理和方法,对该技术在CFB锅炉应用中存在的问题进行归纳,为该技术的推广应用提供支持。以国产330 MW CFB锅炉的SNCR脱硝法为例,分析了该脱硝法的工艺特点,对工程应用中出现的脱硝效率偏低、氨水耗量大、氨逃逸浓度高等问题进行分析,提出改变喷枪布置位置、锅炉低氮燃烧优化、喷枪雾化效果优化等对策。工程应用表明,CFB锅炉SNCR脱硝技术成熟,脱硝效率完全满足环保要求。     

电传动车辆用锂离子电池组低温加热方法研究

为提高电动车辆用锂离子动力电池的低温充放电性能,以35 Ah锰酸锂电池为研究对象,研究了低温下电池充放电特性,并采用宽线金属膜加热方法对-40℃下的电池组进行加热和充放电实验。实验结果表明:低温下电池的充放电性能大幅衰减,采用宽线金属膜加热方式能够显著提升电池的低温充放电性能;加热后,电池组可进行大电流充放电,可以满足电动车辆的行驶要求。     

采用低氟溶胶-凝胶法在725℃煅烧温度下制备YBCO超导薄膜的研究

采用低氟溶胶-凝胶法在LaAlO₃(100)基板上制备了YBa₂Cu₃O_7-x (YBCO)薄膜,研究了725℃的煅烧过程中氧含量对最终所得到YBCO薄膜的临界电流密度J_c的影响。研究发现,煅烧过程中氧气含量在100-1700 ppm范围内时,所获得的YBCO薄膜均具有良好的双轴织构特征。然而,当氧气含量较小时,所获得的YBCO薄膜致密性差,J_c较低。随着氧气含量的增大,YBCO薄膜表面逐渐变得致密。当氧气含量增加到300ppm时,YBCO薄膜表面较致密,J_c值达到4.3MA/cm₂。继续增大氧含量,薄膜表面出现富铜的第二相颗粒并逐渐增多,导致薄膜J_c降低。