The role of NO2 in the reduction of NO by hydrocarbon over Cu-ZrO2 and Cu-ZSM-5 catalysts

The reduction of NO _x with propene or propane in the presence of 1 or 4% O₂ was studied at low conversions over a 7.4 wt% Cu-ZrO₂ and a 3.2 wt% Cu-ZSM-5 catalyst. The rates of N₂ production were compared in experiments using only NO or a mixture of NO and NO₂ in the feed. They were also compared with the rates of NO₂ reduction to NO under the same conditions, and of NO oxidation to NO₂ in the absence of hydrocarbon. It was found that the reduction of NO₂ to NO was very fast, consistent with literature data. The data were best explained by a reaction scheme in which the hydrocarbon was activated primarily by reaction with adsorbed NO₂ to form an adsorbed oxidized N-containing hydrocarbon intermediate, the reaction of which with NO was the principal route to produce N₂ under lean NO _x conditions.On leave from State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China.     

ZnO-B2O3-P2O5系封接玻璃的研究

采用熔融法制备了ZnO-B2O3-PO5 系无铅磷酸盐封接玻璃，研究了组成对玻璃结构、特征温度、热膨胀和化学稳定性的影响。结果表明：B2O3和P2O5为玻璃网络形成体，ZnO含量较低时可以参与到玻璃网络结构中，提高玻璃的稳定性；玻璃转变点Tg、熔制温度Tm、封接温度Ts、软化点Td都随P2O5／B2O3减小而增加；B2O3／ZnO是影响玻璃熔制温度的主要因素；ZnO含量对玻璃密度和热膨胀系数影响较大。ZnO-B2O3-PO5 系玻璃在中性环境下的化学稳定性较好。。     

金属间化合物CePd5，PrPd5和NdPd5的晶体结构

稀土金属对富Pd合金的氢化性能、磁学性能和催化性能有显著的影响，对Pd-RE台金系中最富Pd的化合物的研究是有意义的。本工作通过恰当的熔炼和热处理工艺制备出单相的金属间化合物CePd5，PrPd5和NdPd5，并应用X射线衍射分析确定了它们的晶体结构和晶格参数。研究发现：在Pd-Ce二元系中，最富Pd的化合物是具有CaCu5型六方结构的CePd5；而在Pd-Pr和Pd-Nd二元系中最富Pd的化合物分别是具有SmPt5型正交结构的PrPd5和NdPd5。报道了经指标化的这3种金属间化合物的X射线衍射数据，确定CePd5的晶格参数a=0．5372nm，c=0．4178nm；PrPd5和NdPd5的晶格参数分别是a=0．5278nm，b=0．9239nm，c=2．575nm和a=0．5265nm，b=0．9219nm，c=2．570nm。并对Pd-RE合金系和Pt-RE合金系中最富Pd化合物的化学计量和晶体结构进行了对比。     

锻造工艺对TA5钛合金组织和性能的影响

着重研究了TA5钛合金锻造工艺对组织与性能的影响。采用二次真空熔炼熔铸的α/α＋β转变温度为990-1000℃的TA5钛合金,在β相区开坯,经多火次中间锻造后,对其最后一火次的锻造,改变锻造温度和变形量共8种工艺方案进行实验,考察锻造温度和变形率对组织和性能的影响。结果表明：①最后一火次在970℃（α相区）锻造变形,得到的组织为等轴α组织,在1020℃（β相区）变形得到的组织以粗大的片状α组织为主;②锻造变形率对TA5钛合金的拉伸性能影响不明显;③锻造温度对冲击韧性aK影响较大,成品锻造在β相区变形的aK值均高于α相区的水平。     

5CrMnMo钢中、小型热锻模具的强韧化热处理

5CrMnMo钢中、小型热锻模具经强韧化工艺处理后与经常规工艺热处理相比，强韧性、疲劳抗力和使用寿命显著提高，且工艺简单，操作方便，质量稳定。     

Processing, microstructure, and properties of laser remelted Al2O3/Y3Al5O12（YAG） eutectic in situ composite

Laser remelting and rapid solidification were performed in preparing the high-performance Al2O3/Y3Al5O12（YAG） eutectic in situ composite. The microstructure characteristic and solidification behavior were studied using scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS）, X-ray diffractometry（XRD） and simultaneous thermal analysis（STA）. The hardness and fracture toughness were obtained using an indentation technique. The results show that the laser remelted Al2O3/YAG composite has a homogeneous eutectic microstructure without microcrack and pore. The component phases of Al2O3 and YAG are three-dimensionally and continuously reticular connected, and finely coupled without grain boundaries, colonies and amorphous phases between interfaces. The eutectic interspacing is greatly refined with increasing the scanning rate and average is only l μm. The synthetically thermal analysis indicates that the eutectic temperature of Al2O3-YAG is 1 824 ℃, well matching the phase diagram of Al2O3-Y2O3 system. The maximum hardness reaches 19.5 GPa and the room fracture toughness is 3.6 MPa.m^1/2.     

稀土铒(Er)对Al-4.5Mg-0.15Zr合金组织与性能的影响

用硬度法、金相显微镜、扫描电镜和力学性能检测等方法,研究了不同含量的稀土元素铒对Al-4.5Mg-0.15Zr合金的显微组织、再结晶温度、力学性能的影响.试验结果表明,添加0.4%Er的合金铸态组织晶粒细化,枝晶间距明显减小,其再结晶温度提高了约25℃,合金的硬度与抗拉强度也有所提高.     

铝/钢焊接接头界面Fe2Al5生长模拟研究

基于蒙特卡罗随机模型,模拟铝钢焊接接头界面金属间化合物Fe2Al5的生长过程。针对Fe2Al5的特殊晶体结构,通过随机选定Fe2Al5的c轴方向与形核界面的夹角来确定晶粒生长取向,以实际焊接过程的热循环作为模型的温度参考,采用局部抽象的网格之间的结合能的变化作为生长驱动力来建立模型。模拟结果表明,不同形核取向下的晶粒生长存在明显的竞争生长现象,而夹角为90°的晶粒生长竞争优势明显,使界面上生长的Fe2Al5呈现“板条状”分布,导致这一现象的根本影响因素为Fe,Al原子在Fe2Al5晶粒中的扩散机制不同,这与实际的试验结果非常符合。     

Improved Corrosion Resistance of Selective Laser Melted Ti–5Cu Alloy Using Atomized Ti–5Cu Powder

The different types of metal powder used for selective laser melting(SLM) process would cause distinct corrosion behavior due to the uniformity of the obtained microstructure.The SLM-produced Ti–5Cu alloy using atomized Ti–5Cu metal powder(SLMed Ti–5Cu) in this work reveals a relatively uniform microstructure with overwhelming acicular α/α′ phase and shows great advantages on corrosion resistance compared with the SLM-produced Ti–5Cu alloy using the mixture powder(SLMedM Ti–5Cu).The effect of the micro-galvanic cells decreases due to the undetectable Ti_2Cu phase in the microstructure of the SLMed Ti–5Cu.An apparent passivation behavior was observed for SLMed Ti–5Cu instead of severe pitting phenomenon for the SLMed-M Ti–5Cu.The charge transfer resistance of SLMed Ti–5Cu in this work is 10.09 ± 2.63 MΩ cm~2, which is significantly higher than that of SLMed-M Ti–5Cu(4.76 MΩ cm~2).The above result indicates the atomized Ti–5Cu powder plays an important role in the formation of the uniform microstructure of SLMed product, thereby enhancing its corrosion resistance in Hank's solution at 37 ℃.     

阿立哌唑联合草酸艾司西酞普兰对重度抑郁患者多巴胺、5-羟色胺和皮质醇的影响研究

目的:探讨阿立哌唑联合草酸艾司西酞普兰对重度抑郁患者多巴胺（DA）、5-羟色胺（5-HT）和皮质醇的影响。方法:将94例重度抑郁症患者分为观察组和对照组。对照组采用草酸艾司西酞普兰治疗。观察组采用阿立哌唑联合草酸艾司西酞普兰治疗。采用汉密尔顿焦虑量表（HAMD-17）评估患者的抑郁状态。检测两组患者治疗前后DA、5-HT、皮质醇的水平。采用健康状况问卷（SF-36）评估患者的生存质量,包括生理功能、躯体疼痛、生理职能、精神健康、情感职能、生命活力、社会功能、总体健康。观察两组患者治疗过程中不良反应的发生情况。结果:观察组的有效率比对照组高,差异有统计学意义（P<0.05）;两组治疗后的皮质醇、HAMD-17评分显著降低,DA、5-HT显著升高,差异有统计学意义（P<0.05）;观察组治疗后的皮质醇、HAMD-17评分低于对照组,DA、5-HT高于对照组,差异有统计学意义（P<0.05）;两组治疗后的生理功能、躯体疼痛、生理职能、精神健康、情感职能、生命活力、社会功能、总体健康显著升高,差异有统计学意义（P<0.05）;观察组治疗后的生理功能、躯体疼痛、生理职能、精神健康、情感职能、生命活力、社会功能、总体健康高于对照组,差异有统计学意义（P<0.05）。两组的不良反应发生率差异无统计学意义（P>0.05）。结论:阿立哌唑可进一步调节重度抑郁患者DA、5-HT和皮质醇的水平,提高临床疗效,改善生存质量。