不同载体对甲醇分解钯催化剂性能的影响

用浸渍法制备了Pd/γ-Al2O3和Pd/Ce0.65Zr0.35O22种甲醇分解催化剂。采用XRD,NH3-TPD(NH3-Temperature-Programmed Desorption),XPS及H2-TPR(H2-Temperature-Programmed-Redution)等手段对2种催化剂的结构和性能进行表征,并考察了催化剂上甲醇低温分解的活性。结果表明,Pd/Ce0.65Zr0.35O2催化剂具有较弱的表面酸性及良好的低温还原性能;XPS结果表明2种催化剂中的Pd均以氧化态形式存在,并且Pd在Ce0.65Zr0.35O2固溶体上呈高度分散状态,Pd与Ce间具有较强的相互作用。结合活性考察可知,Pd+的存在有利于甲醇的分解。Pd/Ce0.65Zr0.35O2催化剂具有高的催化活性,220℃时甲醇转化率接近100%。     

双金属催化剂Pd-Co_y/Al_2O_3的协同催化性能研究

通过等体积浸渍法制备了单金属Pd/Al_2O_3催化剂和双金属Pd-Coy/Al_2O_3催化剂,并用于催化2-乙基蒽醌加氢反应。利用N2吸脱附、ICP-AES、XRD、CO化学吸附、TEM、EDX、XPS等表征催化剂的比表面、物相结构以及电子结构。加氢结果发现与单金属Pd/Al_2O_3催化剂相比,双金属Pd-Co0.2/Al_2O_3催化剂加氢效率从11.8 g/L提高到13.5 g/L,选择性从87.2%提高到95.2%。从XPS表征结果发现,催化剂掺杂Co后,一部分Pd颗粒将电子转移到氧化的Co上,形成Pd-Coδ+结构。由羰基活化机理可知,Coδ+吸附C=O中氧的孤对电子,活化C=O,使得C=O加氢反应变得更容易,从而Pd-Co催化剂表现出高催化效率。     

用乙酰丙酮钯作前驱物制备Pd/C催化剂的研究

分别采用乙酰丙酮钯、氯化钯和硝酸钯作前驱物,用浸渍-还原法制备了一系列Pd/C催化剂,以松香歧化反应评价其活性,研究了活性炭类型、载体预处理、溶剂、还原方法及温度等因素对Pd/C催化剂活性的影响.结果表明,采用具有较大比表面积和孔容的活性炭作载体有利于钯在其表面的均匀分布和催化剂活性的提高;以Pd(acac)2作前驱体,以及使用极性较强的溶剂与用无机配合物前驱体相比,制备的Pd/C催化剂活性较高;TG-DTA分析表明Pd(acac)2在350℃下完全分解,基于此结果,作者在350℃条件下采用氢气干法还原,制备出活性略高于从日本进口的Pd/C催化剂.     

Pd/CeCoOx催化剂上Pd组分分散性改进及其NGVs尾气净化性能

近年来,天然气汽车（NGVs）尾气净化三效催化剂的研究主要集中在具有高分散性的负载型贵金属催化剂。本文利用金属有机骨架（MOFs）模板法制备了纳米结构的CeCoOx复合氧化物作为载体,并与传统溶胶-凝胶法（SG）制备的铈钴氧化物比较,探究了贵金属Pd在两种催化剂载体上的分散状态及其对催化性能的影响。结果表明,以CeCo-MOFs材料为前驱体衍生制备的Pd/CeCoOx(M)催化剂其CO、NO、CH4三效催化性能相比溶胶-凝胶法制备的相同组成Pd/CeCoOx(SG)催化剂低了约100 ℃左右,具有更低的低温活性。以CeCo-MOFs为前驱体衍生制备的铈钴复合氧化物晶体粒子更小,晶相结构均匀,具有更大的比表面积,促进了Pd组分分散状态的提高,也丰富了催化剂的氧空位和结构缺陷,显著提高了催化剂的低温三效催化性能。利用MOFs前驱体热分解得到的复合氧化物可以作为三效催化贵金属活性组分分散的良好材料。     

光Fenton反应的Ce-Fe/Al2O3催化剂超声制备及性能表征

采用超声浸渍法和普通浸渍法制备具有相同铁负载量的Ce-Fe/Al2O3催化剂,以解决光Fenton反应过程中催化剂活性低的问题。通过扫描电镜（SEM）、氢程序升温还原（H2-TPR）、紫外可见漫反射（DRS）、比表面积分析（BET）及XPS等手段分别表征催化剂的表面形貌、还原性能、光吸收特性、比表面积特性及活性组分铁的价态和表面分布,利用媒介黄的光Fenton脱色反应考察催化剂的活性和稳定性。结果表明：超声浸渍20 min使活性组分Fe2O3分散均匀,有效抑制Fe2O3颗粒的长大,增加催化剂对光的吸收;比表面积从221.3增大到247.8 m^2/g,改善了催化剂的微孔结构;催化剂表面铁含量从0.24%提高到0.38%,提高了催化剂的催化活性。在pH6.0条件下,60 min内可使200 mg/L媒介黄完全脱色。     

Pt/Co双金属纳米溶胶的制备及催化制氢性能

采用化学共还原法制备了聚乙烯吡咯烷酮(PVP)稳定的Pt/Co双金属纳米溶胶,利用UV-Vis、TEM等对所合成的Pt/Co双金属纳米溶胶进行了表征,并系统研究了PVP用量,还原剂用量,双金属比例对该溶胶型纳米双金属催化剂活性的影响。结果表明:所制备的Pt/Co双金属纳米溶胶的平均粒径在2~3 nm之间,大部分双金属纳米溶胶催化剂催化NaBH4制氢的活性都优于单金属Pt和Co纳米溶胶,Pt10Co90双金属纳米溶胶的催化活性最高,其催化NaBH4制取氢气的活性可以达到8800 mol-H2·mol-催化剂-1·h-1,该双金属纳米溶胶催化NaBH4水解反应的活化能为61.8 kJ/mol。所制备的Pt/Co双金属纳米溶胶催化剂具有很好的稳定性,即使在4次催化试验后该催化剂仍然保持着较高的催化活性。     

制备条件对Pd/TiO_2催化剂上对羧基苯甲醛加氢性能的影响

采用浸渍法以TiO2成型载体制备了Pd/TiO2催化剂,考察了浸渍液pH值、Pd负载量、焙烧温度以及还原温度等因素对粗对苯二甲酸(CTA)中的主要杂质对羧基苯甲醛(4-CBA)的加氢精制性能的影响,并采用BET、XPS、XRD、H2-TPR等手段对催化剂进行了表征。结果表明,浸渍液pH值的升高会造成催化剂表面Pd原子富集,导致催化剂比表面积降低。Pd负载量0.5%时,催化剂所提供的活性中心数目足以满足4-CBA加氢所需。适当提高催化剂焙烧温度,有利于含钯前驱体的分解,催化剂还原温度过高时,会造成Pd/TiO2催化剂活性的迅速降低。Pd/TiO2催化剂的适宜制备条件为:浸渍液pH=2.0、Pd负载量0.5%、催化剂焙烧温度400℃、还原温度低于200℃。     

La助剂对Pd-AL2O3催化C3H8氧化性能的研究

采用不同稀土La前驱体浸渍掺杂改性Pd/γ-Al2O3催化剂,利用多功能催化性能评价装置测试不同催化剂的C3H8催化氧化性能,并通过H2-TPR、XRD、XPS等手段对催化材料进行结构表征,结果表明：La能促进贵金属钯分散,增强钯与载体相互作用,稳定高活性Pd2+物种,从而提高了催化剂的C3H8催化氧化性能。在选用不同La前驱体改性的Pd/γ-Al2O3催化剂中,硝酸镧改性效果最佳,能更好地促进活性金属钯的分散和Pd2+高活性物种的稳定。相比Pd/γ-Al2O3,La改性催化剂均降低了C3H8和NO的反应转化温度。选用不同La前驱体对催化活性影响存在差异的主要原因是La前驱体添加而引起的金属-载体相互作用和活性贵金属钯的分散状态变化。     

以醋酸钌为前驱体的Ru/C催化剂在葡萄糖加氢制取山梨醇反应中活性的研究

以醋酸钌为前驱体,用浸渍还原法制备Ru/C催化剂,以常压下葡萄糖加氢制取山梨醇的反应评价其活性,并用透射电子显微镜(TEM)及X射线衍射对其进行表征,研究了活性碳类型、温度、浸渍和还原时间、pH值、不同前驱体及有机助剂的加入等因素对Ru/C催化剂活性的影响.结果表明,适当的活性碳粒度、大的比表面和孔容有利于Ru粒子在活性碳表面均匀分布,提高催化活性.80~90℃的温度,8~10h的浸渍时间,6~8h还原时间及7~8的pH值有利于Ru粒子在活性碳载体上形成高分散、高活性的Ru/C催化剂.加入有机助剂使催化剂活性明显高于没有加入有机助剂的催化剂.不同的前驱体对Ru/C催化剂在该反应中的催化活性有较大的影响,醋酸钌是一种制备Ru/C催化剂较好的前驱体.     

超声浸渍法制备Pd/Al_2O_3催化剂及其催化硝基苯加氢性能

以粉状γ-Al2O3为载体,分别采用超声浸渍和普通浸渍方法制备了Pd含量为5%的负载型催化剂,并将其用于硝基苯加氢反应。采用XPS和扫描电镜等手段对催化剂的理化性质进行了分析,考察了浸渍方法对催化剂活性金属分散度的影响。结果表明,与普通浸渍法相比,超声浸渍法制备的负载型Pd催化剂金属分散度明显提高,因而对硝基苯加氢反应表现出较高的催化活性。以KBH4为还原剂,通过超声浸渍制备的负载型Pd催化剂具有较高的钯分散度,在硝基苯加氢反应中表现出更高的催化活性。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.