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Bowker  Michael  Cristofolini  Marco  Hall  Matt  Fourre  Elodie  Grillo  Federico  McCormack  Elin  Stone  Peter  Ishii  Masaru 《Topics in Catalysis》2007,42(1-4):341-343
In this paper we report the fabrication of model catalysts prepared to understand the structure of the BaO surface. This utilises the ‘inverse’ catalyst method, that is, the oxide layer is fabricated onto the top of a metal single crystal surface. We show that we can atomically resolve the surface structure of BaO(111) and that it presents a (2×2) reconstruction at its surface. Under other dosing conditions we can produce a layer which is metastable at 573K, which we believe to be the peroxide, BaO2. We have shown that the BaO layer can store NOx from a mix of NO and oxygen, even under the extremely low exposure conditions of UHV, proving that the NOx storage process is a facile one. The results indicate that it is not necessary to have NO2 in the gas phase in order to store NOx.  相似文献   
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In order to develop a methodology for measuring the occurrence and circumstances of sudden unexpected adult deaths due to cardiac and to unidentified causes throughout England, a stratified random pilot sample of 12 of the 133 coroner's jurisdictions in England was invited to survey prospectively a quota sample of 78 consecutive white Caucasians, aged from 16 to 64 years, with no history of ischaemic heart disease, who were last seen alive within 12 h of being found dead, and for whom a coroner's post-mortem examination found either a cardiac or no identifiable cause of death. Eleven (92%) coroners participated. In a median of 105 days (range 21-169), 65 cases (83% of the quota) were ascertained (54 (83%) males). Of the ascertained cases, registration forms were received on 62 (95%), tissue specimens on 63 (97%), and post-mortem reports on 58 (89%). Death was witnessed in 58%, of which 35% were 'instantaneous'. The median time from symptom onset to death was 40 min. In unwitnessed deaths, the median time since last being seen alive was 90 min. Sixty-eight per cent of all deaths were attended--by a relative in 34%, passer-by (8%), ambulance crew (32%), nurse (11%), doctor (38%), and police (9%). Cardio-pulmonary resuscitation was attempted in 38 of the 42 attended deaths. Sixty-seven per cent were taken ill at home, 12% at work, 12% in a public place, and 10% elsewhere. The certified cause of death was ischaemic heart disease in 89%, in whom coronary thrombosis and/or myocardial damage was absent in 6 cases (9%). In the remainder, the certified cause was hypertensive heart disease (5%), hypertrophic obstructive cardiomyopathy (3%), 'cardiomegaly' (1.5%) and 'sudden cardiac arrhythmia' alone (1.5%). A retrospective audit of coroner's records revealed the median case ascertainment rate was 75%. This approach to surveying sudden unexpected adult death nationally resulted in a high response rate (92%) from coroners, consultant pathologists and their staff, the identification of a large proportion of eligible cases, and complete information in most of the identified cases. In from 2% to 15% of cases, death may have been either purely dysrhythmic or due to a sudden adult death syndrome.  相似文献   
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The successful campaign against smoking will long be celebrated as a landmark achievement of public health. Recently, a prominent component of this campaign has been the portrayal of environmental tobacco smoke as a major health risk. To this day, however, the scientific basis for this later contention remains speculative. The elevation of heuristic hypotheses into official precepts raises an intriguing ethical question: Should a claim of best intentions justify representing conjecture as scientific knowledge in public policy formulation?  相似文献   
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The photocatalytic reforming of glycerol to hydrogen over palladium and gold modified TiO2 catalysts is reported. The rate of hydrogen production exceeds that measured for the photoreforming of methanol over both catalysts with the palladium catalyst performing approximately four times better than the gold. The reaction occurs under ambient conditions and neither system suffered from poisoning after extensive testing. This therefore offers a potentially attractive route by which one of the major waste products from the manufacture of biodiesel can be converted into a useful product.  相似文献   
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A study into the photoconductance of poly(N-vinyl carbazole) partly oxidized to introduce cation radicals is described (mole fraction < 4 × 10?3). These materials are shown to be photoconductors whose response to illumination is time dependent. Their photoconductive behaviour has been studied as a function of extent of oxidation, field strength, temperature, light intensity and irradiating wavelength. The observed response is discussed in terms of a model for the amorphous state in which there are accessible levels in the forbidden gap for interaction with photopromoted electrons or holes. Variation in the role of level as trap or recombination centre with external conditions is shown to form, in part, an adequate model for behaviour. However, light intensity and temperature dependence does indicate that there is a significant change of the distribution of levels in the for-bidden gap as the temperature is reduced to ~ ?20°C, possibly due to a change in structure or mode of motion.  相似文献   
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The visual accomodative response is measured during dark field viewing and while engaged in a visual search task. A laser optometer is used to compare performance using microfiche and hard-copy displays. Results indicate a marked bias in the direction of the individual's resting accomodative state during all conditions of display viewing. Implications of these results and those from other studies are discussed with respect to future research in display design.  相似文献   
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The main purpose of the present study was to examine the links between sports participation and self-esteem, with particular interest in the possible mediating role of physical self-esteem. The participants in this study were 382 students (167 boys; 215 girls) in Grades 5-8. Participants completed a series of paper and pencil measures, detailing their sports participation, as well as their self-perceptions concerning physical and general self-esteem. Sports participation was related to all indices of self-esteem and this was equally true for boys and girls. Two distinct but related factors were identified as components of physical self-esteem (Physical appearance and Physical competence), differentially associated with self-esteem for boys and girls. Results supported a mediational model, with physical self-esteem mediating the relationship between sports participation and general self-esteem. Significant sex differences were noted with regard to specific indices of physical self-esteem. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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