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61.
D. M. dos Anjos K. B. Kokoh J.M. Léger A.R. DE Andrade P. Olivi G. Tremiliosi-Filho 《Journal of Applied Electrochemistry》2006,36(12):1391-1397
Pt–Mo alloy electrocatalysts were prepared by an arc-melting furnace process to investigate the origin of their enhanced activity toward ethanol oxidation. Two Mo contents were chosen in zones of the binary phase diagram where they are supposed to form either a pure alloy mixture or a solid solution. Pt–Mo alloy catalysts were more active than Pt-alone. Gradual Mo dissolution at the electrode surface was observed after voltammetric and chronoamperometric measurements. The dissolved Mo contributed to the catalytic effect of the electrode as underpotentially deposited (upd) adatoms. This dissolution probably also leads to an increase in the electrode surface roughness. Low molybdenum content in the electrode material enhances the activity toward ethanol oxidation when compared to Pt-alone. Ethanol oxidation was also investigated by in situ infrared reflectance spectroscopy in order to determine the presence of adsorbed intermediates like CO species. Acetaldehyde, acetic acid and CO2 were also found by spectroscopic experiments. 相似文献
62.
K. K. Soni D. B. Williams J. M. Chabala R. Levi-Setti D. E. Newbury 《Oxidation of Metals》1991,36(5-6):361-378
The high-temperature oxidation behavior of binary Al-Li alloys has been characterized by scanning electron microscopy and secondary ion mass spectrometry in order to understand the mechanism of rapid oxidation in these alloys and to correlate the oxide morphology to its microchemistry. The oxide scale developed on polished specimens during short exposures in air at 530°C shows characteristic nodules that usually nucleate at grain boundaries. Examination of the alloy surface after removal of the oxide layer shows that the initial growth of the oxide nodules occurs laterally in addition to thickening normal to the oxide/alloy interface. Microchemical analysis of the oxide film with a scanning ion microprobe reveals a thick Li-oxide layer at the oxide/gas interface indicating preferential oxidation of Li at the free surface; the rest of the oxide film is composed of both Al- and Li-rich oxides, probably Li2O and LiAlO2 The presence of trace impurities (K, Na, F, and Cl) in the oxide scale was also detected. A microstructural model for the development of the oxide film in the Al-Li system is presented on the basis of both morphological and microanalytical data obtained in this study; this new model is compared with existing models. 相似文献
63.
64.
DE Gibbons 《Canadian Metallurgical Quarterly》1998,60(11):669-671
The former purchaser-provider split underwent an important change during the last years in UK. Especially since the new government came into office in 1997 the approach to equity and equality in dental health care has been characterised by two decisions. Firstly, the level of commissioning services was shifted from the centre to so-called natural communities of about 100,000 people. Secondly, the groups responsible for planning and providing care are constituted from local medical practitioners, community nurses and social services representatives, in line with the Regional Health Authority and the national framework "Our Healthier Nation". The new community dental service is expected to be in a better position to improve the situation in areas of social exclusion. 相似文献
65.
M Delgado EJ Munoz-Elias Y Kan I Gozes M Fridkin DE Brenneman RP Gomariz D Ganea 《Canadian Metallurgical Quarterly》1998,273(47):31427-31436
66.
Clients are leaving the hospital "quicker and sicker," and they frequently have acute care needs that must be met by resources outside the hospital setting. Community resources are diverse, vary widely from place to place, and have no central administration. Thus, using them can be challenging for both the nurse, client, and family. Reimbursement mechanisms underlie a person's ability to use resources and receive health care. By presenting two actual case scenarios where clients have mobility problems commonly seen by orthopaedic nurses, the authors discuss the community resources available, avenues of access to them, and their reimbursement mechanisms. 相似文献
67.
68.
FIGOLI A HOINKIS J CRISCUOLI A FRANZ C DE RYCKE M BLOCK C DEOWAN S A ISLAM R DRIOLI E 《哈尔滨工业大学学报(英文版)》2012,19(1):63-66
Arsenic is a natural tasteless and odourless element,existing in the earth’s crust at average levels of between two and five thousands micrograms per liter (parts per million) . Arsenic is highly toxic to humans, who are exposed to it primarily from air,food and water. The occurrence of arsenic in groundwater is due to geological composition of soil. High concentrations of arsenic in water are the result of dissolution or desorption of ferric oxides and the oxidation of mineral arsenopyrites. Arsenic in drinking water has an important impact on the human health,especially in the less developed countries. Different methods exist to remove arsenic from aquatic media,and one of them is by adsorption. In this work,the adsorption of both As(III) and As(V) by means of novel microspheres has been investigated. In particular,TiO2 has been embedded into polymeric microspheres PES (PolyEtherSulphone) and PEEK-WC (PolyEtherEther-Ketone) . The main advantages of this encapsulation adsorption material are: no loss of adsorbents into the water stream,easy to be used and scaled-up. 相似文献
69.
PW Roelvink A Lizonova JG Lee Y Li JM Bergelson RW Finberg DE Brough I Kovesdi TJ Wickham 《Canadian Metallurgical Quarterly》1998,72(10):7909-7915
Attachment of an adenovirus (Ad) to a cell is mediated by the capsid fiber protein. To date, only the cellular fiber receptor for subgroup C serotypes 2 and 5, the so-called coxsackievirus-adenovirus receptor (CAR) protein, has been identified and cloned. Previous data suggested that the fiber of the subgroup D serotype Ad9 also recognizes CAR, since Ad9 and Ad2 fiber knobs cross-blocked each other's cellular binding. Recombinant fiber knobs and 3H-labeled Ad virions from serotypes representing all six subgroups (A to F) were used to determine whether the knobs cross-blocked the binding of virions from different subgroups. With the exception of subgroup B, all subgroup representatives cross-competed, suggesting that they use CAR as a cellular fiber receptor as well. This result was confirmed by showing that CAR, produced in a soluble recombinant form (sCAR), bound to nitrocellulose-immobilized virions from the different subgroups except subgroup B. Similar results were found for blotted fiber knob proteins. The subgroup F virus Ad41 has both short and long fibers, but only the long fiber bound sCAR. The sCAR protein blocked the attachment of all virus serotypes that bound CAR. Moreover, CHO cells expressing human CAR, in contrast to untransformed CHO cells, all specifically bound the sCAR-binding serotypes. We conclude therefore that Ad serotypes from subgroups A, C, D, E, and F all use CAR as a cellular fiber receptor. 相似文献
70.
专家系统是人工智能的一个分支,是一种模拟专家决策能力的计算机系统,知识库是系统的重要组成部分,是系统的核心。本文结合纺织工艺设计及管理专家系统介绍了基于知识的专家系统的概念和结构,对系统中知识的获取、存储方式予以说明.并对其知识的表示方法加以阐述。 相似文献