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Studies on the Catalytic Properties of Magnesia Supported on γ-Alumina

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Chemical Research in Chinese Universities 2002年第2期18卷 196-199页

作者： JIAO Qing ze ZHAO Yun LI Xiao dan evans dg DUAN Xue Key Laboratory of Science and Technology of Controllable Chemical Reactions Ministry of EducationBeijing University of Chemical TechnologyBeijing 100029P.R.China

We have shown that MgO can be dispersed on γ Al 2O 3 with different loadings. The observed dispersion capacity of MgO on the surface of γ Al 2O 3 is higher than the theoretical monolayer dispersion value. The surface area and the maximum in the pore size distribution gradually decrease with the increase in MgO content at low loadings. The surface area and the maximum in the pore size distribution of MgO/ γ Al 2O 3 decrease more rapidly when the MgO content is large because the pores of γ Al 2O 3 become blocked. When small amounts of MgO are dispersed on the surface of γ Al 2O 3, the catalyst is very active and shows a good selectivity for the synthesis of glycol ethers.

关键词： Magnesia Alumina Dispersion Glycol ether

Studies of the Catalytic Activity and Deactivation of Calcined Layered Double Hydroxides in the Reaction of Ethanol with Propylene Oxide

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Chemical Research in Chinese Universities 2002年第2期18卷 192-195页

作者： JIAO Qing ze ZHAO Yun ZHANG Yi qing evans dg DUAN Xue ZHOU Zi-niu The Key Laboratory of Science and Technology of Controllable Chemical Reactions Ministry of EductionBeijing University of Chemical TechnologyBeijing 100029P.R.China Yixing Auxiliary Chemicals Plant Jiangsu 214262P.R.China

The reaction of ethanol with propylene oxide over calcined layered double hydroxides(CLDH) was investigated. The results show that CLDH has a good activity and a good selectivity, but the activity and the selectivity of CLDH decrease when CLDH reforms LDH- the so called 'memory effect'. The influence of the 'memory effect' on the CLDH returning to LDH was studied by the hydration reaction. It is shown that the 'memory effect' is not complete, and the decreases of the Mg/Al molar ratio of LDH and the crystallite size due to the increase of the hydration reaction time result in the drop of the activity and the selectivity.

关键词： Ethanol, Propylene oxide Calcined layered double hydroxide 'Memory effect' Hydration

新型铜基催化剂的制备及其在湿式催化氧化中的催化性能

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新型铜基催化剂的制备及其在湿式催化氧化中的催化性能

稀土元素Ce的引入对铜基水滑石结构及催化性能的影响

第2届全国工业催化技术及应用年会

作者：张立红李峰 evans dg 段雪北京化工大学可控化学反应科学与技术基础教育部重点实验室

采用传统的共沉淀法制备了铜锌铝、铜锌铁铝及铜锌锰铁铝系列的碳酸根型层状双羟基氢氧化物,通过X射线衍射(XRD)、红外光谱(FT-IR)、热重及质谱联用(TG-MS)及X光电子能谱 (XPS)等研究手段对LDHs及其在773 K的焙烧产物的晶相组成、结构... 详细信息

采用传统的共沉淀法制备了铜锌铝、铜锌铁铝及铜锌锰铁铝系列的碳酸根型层状双羟基氢氧化物,通过X射线衍射(XRD)、红外光谱(FT-IR)、热重及质谱联用(TG-MS)及X光电子能谱 (XPS)等研究手段对LDHs及其在773 K的焙烧产物的晶相组成、结构和表面化学状态进行了分析。结果表明,在焙烧产物中均存在一定形式相互作用的复合金属氧化物,层状前体的结构特征决定了其焙烧产物的物化性能。另外,通过对LDHs焙烧产物的苯酚催化氧化性能研究发现,含铜锌铁铝氧化物催化荆具有较强的催化活性,这与其表面催化活性中心Cu2+离子的化学状态和分布状态密切相关。

关键词：复合氧化物层状双羟基化合物苯酚氧化催化作用

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稀土元素Ce的引入对铜基水滑石结构及催化性能的影响

New Identities for Weak KAM Theory(For Haim Brezis,in continuing admiration)

第2届全国工业催化技术及应用年会

作者：常铮李峰 evans dg Forano C De ROY M 段雪北京化工大学可控化学反应科学与技术基础教育部重点实验室北京化工大学 Laboratoire des Matériaux Inorganiques Université Blaise PascalClemont-Ferront

采用共沉淀法制备出含稀土元素Ce的铜锌铝水滑石,通过XRD、TG、IR、元素分析和 HPLC等表征手段对其结构和性能进行了分析。结果表明,Ce相对于Al的含量小于10％的夺件下可以得到晶相单一、结晶度较好的含Ce铜基水滑石。含Ce的铜基催化剂... 详细信息

采用共沉淀法制备出含稀土元素Ce的铜锌铝水滑石,通过XRD、TG、IR、元素分析和 HPLC等表征手段对其结构和性能进行了分析。结果表明,Ce相对于Al的含量小于10％的夺件下可以得到晶相单一、结晶度较好的含Ce铜基水滑石。含Ce的铜基催化剂在苯酚氧化反应中表现出深度氧化能力,对最终氧化产物——小分子羧酸及CO2的选择性为100％,并能够提高催化剂的稳定性,有效地减弱各金属元素的流失,活性组分铜的流失量仅为纯铜基催化剂的20％,同时反应后重新恢复的水滑石元素组成和晶体结构均没有发生改变。

关键词： Ce 铜基水滑石催化性能

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Chinese Annals of Mathematics,Series B 2017年第2期38卷 379-392页

作者： Lawrence Craig evans Department of Mathematics University of CaliforniaBerkeleyUSA.

This paper records for the Hamiltonian H =1/2|p|~2+ W(x) some old and new identities relevant for the PDE/variational approach to weak KAM theory.

关键词： Weak KAM theory, Effective Hamiltonian, Hamiltonian dynamics

Social Computing Unhinged

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Journal of Social Computing 2020年第1期1卷 1-13页

作者： James evans University of Chicago ChicagoIL 60637and Santa Fe InstituteSanta FeNM 87501USA.

Social computing is ubiquitous and intensifying in the 21st *** used to reference computational augmentation of social interaction through collaborative filtering,social media,wikis,and crowdsourcing,here I propose to expand the concept to cover the complete dynamic interface between social interaction and computation,including computationally enhanced sociality and social science,socially enhanced computing and computer science,and their increasingly complex combination for mutual *** recommends that we reimagine Computational Social Science as Social Computing,not merely using computational tools to make sense of the contemporary explosion of social data,but also recognizing societies as emergent computers of more or less collective intelligence,innovation and *** further proposes we imagine a socially inspired computer science that takes these insights into account as we build machines not merely to substitute for human cognition,but radically complement *** leads to a vision of social computing as an extreme form of human computer interaction,whereby machines and persons recursively combine to augment one another in generating collective intelligence,enhanced knowledge,and other social goods unattainable without each *** the example of science and technology,I illustrate how progress in each of these areas unleash advances in the others and the beneficial relationship between the technology and science of social computing,which reveals limits of sociality and computation,and stimulates our imagination about how they can reach past those limits together.

关键词： social computing complex systems computer supported cooperative work computational social science artificial intelligence human computer interaction human-centered computing

Review： Sugar beets as a substitute for grain for lactating dairy cattle

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Journal of Animal Science and Biotechnology 2017年第3期8卷 539-548页

作者： Essi evans Ulrike Messerschmidt Technical Advisory Services Inc 64 Scugog St Bowmanville ON L1C3J Canada KWS SAAT SE Grimsehlstr. 31 P.O. Box 1463D-37555 Einbeck Germany

Dairy cows are customarily given grains and highly digestible byproduct ingredients as additions to forage to support milk production. In many parts of the world growing seasons are short, and the grain crops that can be grown may not provide adequate yields. Sugar beets, on the other hand are relatively hardy, and dry matter yields surpass the yields of most grain crops. There are however, perceptions that beets may not be suitable as a feed ingredient due to the fact that the storage form of carbohydrate is sugar rather than starch. With little analytical support, sugar has been rejected in many feeding programs with the view that sugar reduces rumen pH, fiber digestion and microbial yield. This review explores available facts revolving around these concerns. Information regarding the feeding of sugar beets is provided and the use of sugar beets as a partial replacement for grain is proposed.

关键词： Dairy cattle Feed beets Fodder beets Methane Sugar Sugar beets

A CLASS OF ASYNCHRONOUS MATRIX MULTI-SPLITTING MULTI-PARAMETER RELAXATION ITERATIONS

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Journal of Computational Mathematics 1998年第3期16卷 221-238页

作者： Bai, ZZ Wang, DR evans, DJ Chinese Acad Sci ICMSEC Beijing 100080 Peoples R China Shanghai Univ Dept Math Shanghai 201800 Peoples R China Loughborough Univ Technol Dept Comp Studies Loughborough LE11 3TU Leics England

A class of asynchronous matrix multi-splitting multi-parameter relaxation methods, including the asynchronous matrix multisplitting SAOR, SSOR and SGS methods as well. as the known asynchronous matrix multisplitting AOR, SOR and GS methods, etc., is proposed for solving the large sparse systems of linear equations by making use of the principle of sufficiently using the delayed information. These new methods can greatly execute the parallel computational efficiency of the MIMD-systems, and are shown to be convergent when the coefficient matrices are H-matrices. Moreover, necessary and sufficient conditions ensuring the convergence of these methods are concluded for the case that the coefficient matrices are L-matrices.

关键词： system of linear equations asynchronous iteration matrix multisplitting relaxation convergence

ON THE CONVERGENCE OF ASYNCHRONOUS NESTEDMATRIX MULTISPLITTING METHODS FOR LINEARSYSTEMS

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Journal of Computational Mathematics 1999年第6期17卷 575-588页

作者： Bai, ZZ Wang, DR evans, DJ Acad Sinica State Key Lab Sci Engn Comp Inst Computat Math & Sci Engn Comp Beijing 100080 Peoples R China Shanghai Univ Dept Math Shanghai 201800 Peoples R China Loughborough Univ Technol Parallel Algorithms Res Ctr Loughborough LE11 3TU Leics England

A class of asynchronous nested matrix multisplitting methods for solving large-scale systems of linear equations are proposed, and their convergence characterizations are studied in detail when the coefficient matrice... 详细信息

关键词： solution of linear systems asynchronous parallel iteration matrix multisplitting relaxation method convergence