高效氟化表面处理对化学制氢催化剂性能影响

硼氢化物催化水解反应过程中,产生的氢气速率是和催化剂性能密切相关的.采用一种合金作为固体催化剂是有效的,通常这种合金本身就是一种吸氢材料,譬如文中研究中使用的镁镍系合金Mg2Ni.采用氟化处理的方法可以对其表面进行改性,但更有效的氟化处理方法是通过调节pH值进行反复的循环处理,使得处理后合金的比表面积和活性明显比未处理的增强.文中通过ICPS,SEM和EPMA分析手段对处理前后的合金催化剂进行观察和表征,从而获得处理条件与提高催化剂性能结果的一致性.     

La系储氢合金表面氟化处理技术

通过分析不同HF/KF配比调制的溶液pH及F离子浓度,绘制了可用于对La系储氢合金进行表面处理的溶液组成参考图。通过ICP、EPMA、BET等分析手段对处理前后的合金进行观察和表征,得到氟化处理最佳条件并证明了氟化处理的反应机理包含除去氧化物反应、Ni离子溶出反应和在合金表面形成氟化物反应3个阶段。结合活化速度和电化学特性分析表明,通过氟化处理方法对储氢合金粒子进行表面化学处理,可达到去除合金表面氧化物膜,增加比表面积,保持合金的表面活性和延长合金的耐久性的目的。     

喷雾干燥法制备碳载铂钴镍合金催化剂及其甲醇催化氧化性能研究

本文以氯铂酸、氯化镍和硝酸钴为原料，XC-72炭黑为载体，通过雾化干燥法结合煅烧还原制备碳载铂基（PtCo Ni）分散性好的多元合金纳米粒子催化剂。重点研究表面经过改性的炭黑对合金纳米粒子形成和分散的影响规律，研究碳载PtCoNi（原子比为1:1:1）合金纳米粒子的甲醇催化氧化活性、抗CO中毒能力和耐久性，以及不同原子比对催化氧化甲醇活性和抗CO中毒能力的影响规律。研究结果表明，采用表面改性后的炭黑作为载体，制备的碳载铂基（PtCoNi）催化剂为合金纳米粒子，且纳米粒子在炭黑表面分散均匀，粒径分布在1-4nm，平均粒径为2.3nm；与商用的Pt/C催化剂相比，PtCoNi/C（原子比为1:1:1）催化剂具有更高的甲醇催化氧化活性、耐久性和抗CO中毒性；不同原子比铂基多元催化剂在催化氧化甲醇活性上的顺序为：PtCoNi/C>Pt3CoNi/C>Pt5CoNi/C，抗CO中毒性顺序为：PtCoNi/C>Pt3CoNi/C>Pt5CoNi/C。     

获得高比表面积储氢合金(AB5)的表面处理技术研究

对LaNi4.7Al0.3氟化处理的反应机理、控制反应过程的技术方法、处理前后合金表面结构与性能的变化等进行了深入的研究.结合SEM,EPMA等分析和氢化反应初期活化特性曲线的结果,阐释了氟化处理过程的pH值变化与比表面积变化以及Ni离子溶出现象之间的关系,表明了该方法可达到减少Ni离子流失,增加合金比表面积,同时明显...     

Analysis of the Active Au Species on Au/α-Fe2O3 Catalyst

采用沉积沉淀法制备了CO低温氧化 Au/α-Fe2O3催化剂,利用 X 射线衍射(XRD)、X 射线光电子能谱(XPS)、BET 比表面测定、程序升温还原(H2-TPR)等表征技术,对比了制备过程 pH 值的微小变化、焙烧及光线照射对催化剂结构及催化性能的影响,探明了 Au/α-Fe2O3催化剂的活性物种。结果表明,110 ℃处理的 Au/α-Fe2O3催化剂表面同时存在 Au3+、Au0以及过渡态 Auδ+(0<δ<1),它们对 CO 氧化的活性顺序为 Au3+>Auδ+>Au0;pH 值为 8 条件下制备的催化剂 Au3+含量高、比表面积大,催化性能最好;高温焙烧使氧化态金还原的同时也使载体比表面积严重缩小,催化活性显著下降;紫外线照射可以引起 Au3+的逐渐还原以及 Au0 颗粒的生长,其催化失活作用弱于高温焙烧。     

Au/α-Fe_2O_3 催化剂上金活性物种的分析(英文)

采用沉积沉淀法制备了CO低温氧化 Au/α-Fe2O3催化剂,利用 X 射线衍射(XRD)、X 射线光电子能谱(XPS)、BET 比表面测定、程序升温还原(H2-TPR)等表征技术,对比了制备过程 pH 值的微小变化、焙烧及光线照射对催化剂结构及催化性能的影响,探明了 Au/α-Fe2O3催化剂的活性物种。结果表明,110 ℃处理的 Au/α-Fe2O3催化剂表面同时存在 Au3+、Au0以及过渡态 Auδ+(0δ1),它们对 CO 氧化的活性顺序为 Au3+Auδ+Au0;pH 值为 8 条件下制备的催化剂 Au3+含量高、比表面积大,催化性能最好;高温焙烧使氧化态金还原的同时也使载体比表面积严重缩小,催化活性显著下降;紫外线照射可以引起 Au3+的逐渐还原以及 Au0 颗粒的生长,其催化失活作用弱于高温焙烧。     

AB5型储氢合金作KBH_4燃料电池阳极材料的研究

采用AB5型MwNi3.5Co0.75Mn0.4Al0.3储氢合金作为KBH4碱性燃料电池的阳极材料来代替传统的贵金属催化剂.为提高合金的电催化性能,研究了合金球磨、表面还原包覆改性条件对电催化性能的影响.结果表明:经过氩气球磨改性处理和表面还原包覆铜处理的合金,与铸态合金相比,在大电流范围下的电催化性能有明显改善,并对优化之后的合金阳极进行恒流放电测试,表现出良好的性能.     

激光熔敷镍基合金的耐蚀性

利用激光表面重熔和激光熔敷镍基合金的方法,对２Ｃｒ１３钢汽轮机末级叶片进行了表面改性处理。经显微组织观察、物相分析和阳极极化曲线测定证明,激光处理后的合金组织更细小,表面耐蚀性比处理前更好,熔敷镍基Ｇ１１２合金后的耐蚀性提高尤其显著。实验得出了提高其耐蚀性的优化工艺条件。     

Pd-Ru/Ni(泡沫镍)作为Mg-H2O2半燃料电池阴极的研究

以泡沫镍为基体,采用恒电流沉积法制备了Pd - Ru/Ni(泡沫镍)催化剂.SEM表征发现,Pd - Ru粒子直径约为200 nm,均匀分布在泡沫镍骨架表面,Pd:Ru原子比为6:1.线性电势扫描 伏安法研究表明:Pd - Ru/Ni(泡沫镍)电极对H2 O2电还原反应具有较高的催化性能,起始还原电 .势可达0....     

负载型Cu基结构催化剂的制备及其含氰废气净化性能研究

目的调整Cu基结构催化剂浸渍液的组分,研究其对丙烯腈、氰化氢含氰组分净化效率的影响。方法通过表面改性的方法,在常见的分子筛和氧化物表面负载不同种类与含量的助剂,得到结构催化剂,并且利用X射线衍射(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)、透射电子显微镜(TEM)、比表面积分析仪、催化剂颗粒强度仪,对催化剂的微观形貌、结构特性和机械强度等进行系统表征。利用氢气程序升温还原(H_2-TPR)和氨气程序升温脱附(NH3-TPD),对催化剂表面物种的氧化还原性和酸性进行研究。结果通过筛选发现,添加Fe和Ce助剂得到的结构催化剂,在含氰废气净化过程中表现出优异的催化性能和稳定性。各浸渍组分均匀分布在所用的载体表面,经ICP分析测得催化剂中各负载组分的含量为4.5%Cu+1.1%Ce+1.2%Fe(均为质量分数)。利用该方法得到的催化剂比表面积高,孔道结构丰富,表面物种分布均匀且径向强度超过100 N/cm。含丙烯腈和氢氰酸的废气经过催化剂处理后,高效转化为无害的CO_2、H_2O和N_2。废气中丙烯腈含量小于0.5 mg/m~3,氰化氢小于1.9 mg/m~3,氮氧化物小于100 mg/m~3,均低于国家排放标准的限值,且经过2500h连续反应,未发现明显失活现象。另外,催化剂同时具有较好的丙烷催化燃烧去除性能和水热稳定性,450℃下300 h内丙烷的去除率保持在85%以上。结论开发了一种简捷的方法对常见载体(分子筛、氧化物)进行表面改性处理,调控催化剂表面物种的化学性质。通过浸渍过程赋予其高效净化含氰废气的性能,同时催化剂具有优异的活性、稳定性和机械强度,存在良好的工业化应用前景。     

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。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.