Simple N‐Heterocyclic Carbenes as Ligands in Ullmann‐Type Ether and Thioether Formations

A simple N‐heterocyclic carbene (NHC) derived from 1‐methyl‐3‐ethylimidazolium tetrafluoroborate was found to be an efficient ligand for a range of copper‐catalyzed cross‐coupling reactions, leading to the formation of aromatic ethers and thioethers.

     

白炭黑的液相分散工艺对溶聚丁苯橡胶改性研究

选用数显型高速分散机进行白炭黑环己烷浆液的制备,通过圆盘式离心沉降粒度仪测定了白炭黑在环己烷浆液中的粒径,采用自然沉降法评价了各批次浆液的稳定性。考察了偶联剂种类、用量、搅拌方式、反应温度等条件对浆液分散效果的影响。实验结果表明:硅烷偶联剂KH550的用量为白炭黑质量的10%,在15 000和20 000 r/min搅拌转速下分别分散5 min,温度为10℃时,白炭黑在环己烷中的分散效果最佳。将改性后的白炭黑液相混炼填充至丁苯橡胶中其力学性能相对于干法填充有一定提升。     

The effect of Nb2O5 and ZrO2 additions on the behaviour of Li/MgO and Li/Na/MgO catalysts for the oxidative coupling of methane

Incorporation of Nb₂O₅ or ZrO₂ into both Li/MgO and Li/Na/MgO systems produced ternary and quaternary catalysts, respectively, capable of attaining optimal C₂ yields and selectivities at lower temperatures relative to the unpromoted materials. The degree of enhancement effected by these metal oxide additives was compared to that produced by Li/MgO and Li/Na/MgO catalysts promoted with SnO₂ or Co₃O₄. At reaction temperatures < 700°C, the Li/Co/MgO ternary system showed marked differences in behaviour compared to the other ternary catalysts tested. This was particularly evident in the variation in C₂ selectivity with time on stream during ageing studies of (i) untreated materials, (ii) materials pretreated in CO₂, and (iii) materials dosed periodically with CHCI₃.     

Coupling solved roll contact pressure transverse distribution of HC strip mill

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金属成形过程组织演变的CellularAutomaton模拟技术

结合金属凝固过程的热成形过程的温度场,浓度场,应力应变场等的数值模拟和结晶,再结晶过程中的热力学,动力学条件,建立了金属成形过程组织演变的宏－微观耦合模型,利用ＣｅｌｌｕｌａｒＡｕｔｏｍａｔｏｎ方法。依据建立的模型对Ｋ４１７Ｎｉ基合金叶片的凝固组织形成过程呼热加工过程的再结晶组织进行了模拟。     

静电喷涂在管接箍喷漆生产线中的应用

针对上海宝钢集团公司钢管分公司管接箍生产线自动化程度低、劳动强度大的现状,提出在管接箍喷漆生产线上采用先进的静电喷涂方法。该方法的采用可以缩短管接箍喷漆工艺流程,提高产品质量,降低劳动强度,改善劳动环境,提高劳动生产率     

Effect of Electronic Properties of Catalysts for the Oxidative Coupling of Methane on Their Selectivity and Activity

The oxidative coupling of methane (OCM) to higher hydrocarbons may eventually become an interesting alternative for the chemical utilization of natural gas. Extensive studies have been conducted since the works of Keller and Bhasin [l] and of Hinsen and Baerns [2].     

Accu—Roll轧管机组主减速机输出轴联轴器大过盈量装配

介绍了采用油温加热装配工艺,实现Accu-Roll轧管机组主减速机输出轴联轴器大过盈量装配。     

铝阳极氧化膜原位偶合反应着色工艺研究

在铝阳极氧化(AAO)膜表面,通过N,N＇-二苯基丙二酰胺衍生物与取代苯基重氮盐的原位偶合反应,得到有色的取代苯偶氮N,N＇-二苯基丙二酰胺衍生物,使AAO膜呈黄色.研究结果表明,氧化膜的制作工艺为:电流密度3～3.5A/dm2 (AC),温度25～35℃,时间为1h;偶合反应的条件为:DMF为溶剂,六氢吡啶为催化剂,...     

铝合金连续铸轧凝固过程宏观-微观数学模型的建立及耦合

以等价比热客法处理结晶潜热和以假设的流线边界划分网格节点,建立了连续铸轧铝合金薄带凝固过程的宏观速度场、传热、溶质传输和凝固组织形成的微观数学模型以及连续铸轧铝合金薄带凝固过程的宏观-微观耦合数学模型.同时,以固相分数为媒介,采用宏微观不同的网格尺寸和时间步长,实现了宏观模型与微观模型的耦合.