In situ solid state NMR observation of the methanol-to-hydrocarbons (MTH) process over nanosized and microsized HZSM-5 zeolites

The formation of surface alkoxy species on nanosized HZSM-5 and microsized HZSM-5, after exposure to methanol and subsequent conversion to olefins, has been investigated by in situ solid state NMR. Compared to microsized HZSM-5 zeolite, the nanosized HZSM-5 zeolite was found to exhibit a higher affinity for trapping methanol species. Activation of the adsorbed methanol species resulted in the formation of various surface alkoxy species with different rigid characters, including the carboxylate-like surface species, as evidenced by deconvolution of the related spectra. The present results support the existence of the so-called carbon-pool in the conversion of methanol, which serves as the reaction precursor not only for the coupling of the species to form olefins, but also for uncontrolled polymerization to give coke on the surface. The nanosized HZSM-5 shows a distinct resistance to the formation of carbonaceous deposits on the surface.

Direct observation of subsurface oxygen on the defects of Pd(100)

Oxygen adsorption and desorption on a Pd(100) surface with a mesoscopic defect were studied by photoemission electron microscopy (PEEM). The defect surface, with an area of approximately 200 x 60 mu m(2), behaved differently from the perfect Pd(100) surface towards the adsorption of oxygen. When saturated, both surface oxygen and subsurface oxygen coexisted on the defect surface, whereas only surface oxygen was present on the Pd(100) surface. Upon heating, subsurface oxygen diffused back to the surface and desorbed with surface oxygen at the same time. The difference in oxygen adsorption ability between the defect surface and the perfect Pd(100) surface can be attributed to different structures of these two surfaces. (C) 1999 Elsevier Science B.V. All rights reserved.

听力障碍与听力正常群体视觉注意发展及其机制的比较

One of the most important functions in the individual development is the interaction and integration of each sensory input. There exist two competing theories, i.e. the deficiency theory and the compensatory theory, regarding the origin and nature of changes in visual functions observed after auditory deprivation. The deficiency theory proposed that integrative processes are essential for normal development. In contrast, the compensatory theory stated that the loss of one sense may be met by a greater reliance upon, therefore an enhancement of the remaining senses. Given that hearing impaired children’s learning depends primarily on visual information, it is important to recognize the differences of visual attention between them and their hearing age-mates. Differences among age groups could exist in either selectivity or sustained attention. Study 1 and study 2 explored the selective and sustained attention development of hearing impaired and hearing students with average cognitive ability, aged from 7 years to college students. The analysis and discussion of the results are based on the visual attention development as well as deficiency theory and compensatory theory. According to the results of the study 1 and study 2, the spatial distribution and controlling of the visual attention between hearing impaired and hearing students were also investigated in the study 3 and study 4. The present work showed that: Firstly, both hearing impaired and hearing participants had the similar developmental trajectory of the sustained attention. The ability of children’s sustained attention appeared to improve with age, and in adolescence it reached the peak. The hearing impaired participants had the comparable sustained attention skills to the matched hearing ones. Besides, the results of the hearing impaired participants showed that they could maintain their attention and vigilance on the current task over the observation period. Secondly, group differences of visual attention development were found between hearing impaired and hearing participants. In the childhood, the visual attention developmental speed of the hearing impaired children was slower than that of the hearing ones. The selective attention skill of the hearing impaired were not comparable to the hearing ones, however, their selective skill improved with age, so in the adulthood, hearing impaired students showed the slight advantage in the selective attention skill over the hearing ones. Thirdly, hearing impaired and hearing participants showed the similar spatial distribution in the attention resources. In the low perceptual load condition, both participants were suffered great interference of the distrator at the fixation. In contrast, in the high perceptual load condition, hearing impaired adults were suffered more interference of the peripheral distractor, which suggested that they distributed more attention resources to the peripheral field when faced difficult tasks. Fourthly, both groups showed similar processing in the visual attention tasks. That is, they both searched the target with only the color feature in a parallel way, but in a serial way while processing orientation feature and the features with the combination of the color and orientation. Furthermore, the results indicated that two groups show similar ways in the attention controlling. In summary, the present study showed that visual attention development was dependent upon the integration of multimodal sensory information. Because of the interaction and integration of the input from various sensory, it has a negative impact on the intact sensory at the early stage of one sensory loss, however, it can better the functions of other intact sensory gradually with development and practice.

A hardware proof of concept of a sailing robot for ocean observation

M J Neal, A hardware proof of concept of a sailing robot for ocean observation, IEEE Journal of Oceanic Engineering, 2006 accepted for publication RAE2008

On Models, Modelling and the Distinctive Nature of Model-Based Reasoning

M.H. Lee, On Models, Modelling and the Distinctive Nature of Model-Based Reasoning, AI Communications, 12 (3), pp127-137.1999.

Using participant or non-participant observation to explain information behaviour

Cooper, J., Lewis, R. & Urquhart, C. (2004). Using participant or non-participant observation to explain information behaviour. Information Research, 9(4). Retrieved August 3, 2006 from http://informationr.net/ir/9-4/paper184.html Sponsorship: AHRC (Cooper).

Pre-empting Plateau: the nature of topological transitions in foam

Hutzler, S., Weaire, D., Cox, S.J., Van der Net, A. and Janiaud, E. (2007) Pre-empting Plateau: the nature of topological transitions in foam. Europhys. Lett. 77: 28002 Sponsorship: EPSRC / ESA / ESTEC / Science Foundation Ireland/ Gulbenkian Foundation

Direct observation of Schottky to Ohmic transition in Al-diamond contacts using real-time photoelectron spectroscopy

Evans D A, Roberts O R, Vearey-Roberts A R, Langstaff D P, Twitchen D J and Schwitters M 2007 Direct observation of Schottky to ohmic transition in Al-diamond contacts using realtime photoelectron spectroscopy Appl. Phys. Lett. 91 132114 doi:10.1063/1.2790779