Zinc doped Fe2O3 for boosting Electrocatalytic Nitrogen Fixation to ammonia under mild conditions

Artificial nitrogen fixation is emerging as a promising approach for synthesis of ammonia at mild conditions. Inspired by biological nitrogen fixation based on bacteria containing iron, zinc doped Fe₂O₃ nanoparticles are proposed as an efficient and earth abundant electrocatalyst for converting N₂ to NH₃. In neutral media, it achieves a maximum Faradaic efficiency (FE) of 10.4% and a large NH₃ yield rate of 15.1 μg h^?1 mg^?1_cat. at ?0.5 V vs. reversible hydrogen electrode. This catalyst also exhibits excellent selectivity and stability. Theoretical calculations suggest the reaction follows the associative enzymatic mechanism and it has a barrier of as low as 0.68 eV.     

Model Selection for Unsupervised Learning of Visual Context

This study addresses the problem of choosing the most suitable probabilistic model selection criterion for unsupervised learning of visual context of a dynamic scene using mixture models. A rectified Bayesian Information Criterion (BICr) and a Completed Likelihood Akaike’s Information Criterion (CL-AIC) are formulated to estimate the optimal model order (complexity) for a given visual scene. Both criteria are designed to overcome poor model selection by existing popular criteria when the data sample size varies from small to large and the true mixture distribution kernel functions differ from the assumed ones. Extensive experiments on learning visual context for dynamic scene modelling are carried out to demonstrate the effectiveness of BICr and CL-AIC, compared to that of existing popular model selection criteria including BIC, AIC and Integrated Completed Likelihood (ICL). Our study suggests that for learning visual context using a mixture model, BICr is the most appropriate criterion given sparse data, while CL-AIC should be chosen given moderate or large data sample sizes.     

离心泵并联运行工况点的数值求解

建立了求解多台不同型号离心泵并联运行工况点的数学模型,给出了用数值计算中的“二分法”求解该模型的方法,并附有用Exce l计算的实例。     

稠油微生物开采技术现状及进展

综述了用微生物方法开采稠油的技术现状与进展，论题如下。①概述。②基本方法：异源微生物采油，包括微生物吞吐和微生物驱；本源微生物采油压大港孔店油田的实例。③主要机理，包括产表面活性剂，降解稠油中重质组分及其他。④技术研究，包括机理性、可行性及经济效益研究，列举了国内外6个实例。⑤现场应用，包括国外1个、国内6个实例。⑥该技术的优势及问题。参22。     

HEDP作为润滑油抗磨剂的应用研究

考察了1-羟基乙叉-1，1-二膦酸（二辛）酯（HEDP）的极压抗磨性能以及与硫化异丁烯的复合效应，并用俄歇电子能谱（AES）分析了其四球机试验后钢球表面的元素。结果表明，HEDP作为抗磨剂用于极压性润滑油中，具有优良的极压抗磨性能，其与硫化异丁烯复配也显示出了良好的协同效应。HEDP对于油品的防锈性能具有积极的作用，对有色金属的腐蚀无不良影响，具有多效功能，对于研制低剂量的极压性油品配方具有重要意义。HEDP应用于重负荷车辆齿轮油的全配方中，所调制的复合剂添加量不大于4．5％的GL-5车辆齿轮油符合GB1389592质量标准。     

Synthesis of amphiphilic magnetic microspheres by dispersion copolymerization of styrene and poly(ethylene oxide) macromonomer

Amphiphilic magnetic microspheres ranging in diameter from 5 to 100 µm were prepared by dispersion copolymerization of styrene and poly(ethylene oxide) vinylbenzyl (PEO‐VB) macromonomer (MPEO) in the presence of Fe₃O₄ magnetic fluid. The effects of various polymerization parameters on the average particle size were systematically investigated. The average particle size was found to increase with increasing styrene concentration and initiator concentration. It also increased with decreasing stabilizer concentration and molecular weight of MPEO. The content of the hydroxyl groups localized in the microspheres ranged from 0.01 to 0.2 mmol g^?1. © 2003 Society of Chemical Industry     

纤维在沥青混合料中的应用研究

选用工程中常用的几种纤维,结合工程应用要求,试验分析了纤维的吸湿性、耐热性,并通过网篮析漏试验、动态剪切试验和沉锥试验,讨论了纤维对沥青的稳定和吸附作用,以及纤维对沥青混合料“加筋”效果和作用机理。研究表明有的纤维“吸附、稳定”性能好,而有的纤维“加筋、桥接”效果好,在应用纤维时,应根据纤维的主要特点以及沥青混合料的使用要求来选用。     

储层应力敏感性影响因素研究

全面分析储层应力敏感性产生的机理认为，外部因素的改变会引起储层产生应力敏感性．而储层岩石物性等内部因素对应力敏感性的强弱起决定性作用。室内岩心应力敏感性评价时．仪器与设备的精度、加载与卸载方式、实验用流体类型以及各种人为因素等都会对评价结果产生影响，其中岩心密封套在高压、高温条件下的密闭性会对实验结果产生较大影响。所以储层应力敏感性不应该从孔隙度和渗透率的高低进行简单评价，中、高渗储层和低渗储层在生产过程也都可能表现出较强的应力敏感性现象。     

裂解炉炉管基于风险的检验

管式裂解炉炉管受炉内高温及管内介质压力的共同作用,易发生蠕变等现象,因此,对裂解炉炉管进行风险评价尤为重要。应用API 581基于风险的检验规范对炉管的失效可能性及失效后果分别进行定量计算,并由此得到裂解炉炉管的定量风险结果和基于风险的检验周期,为裂解炉的风险控制与管理提供依据。