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101.
Jing-Long Du Kundalika M. More Sandra S. Eaton Gareth R. Eaton 《Israel journal of chemistry》1992,32(2-3):351-355
The orientation dependence of the electron spin phase memory relaxation time (T) was measured for vanadyl 5-(4-carboxyphenyl)-10, 15, 20-tritolylporphyrin at 22, 50, and 100 K, copper(II) bis(diethyldithiocarbamate) at 50 and 100 K, and copper(II) 5, 10, 15, 20-tetratolylporphyrin at 50, 70, and 100 K in frozen solution. Tm was determined by fitting a single exponential to two-pulse electron spin echo data. The values of Tm were strongly dependent on the orientation of the molecule in the magnetic field. Longer values were obtained when the magnetic field was along a principal axis or along a non-canonical turning point in the spectrum. Shorter values of Tm were observed at intermediate orientations. The orientation dependence of Tm is attributed to molecular motion. The EPR spectra for the three systems examined are approximately axial, so the relevant motion is motion of the molecular z axis with respect to the external magnetic field. Longer values of Tm (slower relaxation) occur for orientations at which the resonant condition is less sensitive to a change in orientation of the molecular z axis. Shorter values of Tm (faster relaxation) occur at orientations for which the resonant condition is more sensitive to a change in orientation of the molecular z axis. 相似文献
102.
The passivation characteristics of sulfuric acid cleaned mild steel in spent Bayer liquor (pH 14.4 and 160 °C) are examined using a high pressure nickel flow loop. An entrained atmosphere of 99.90% v/v oxygen gas is incorporated as an experimental variable along with Reynolds number (141,700 and 50,950) and intensity of fluid flow disturbance. State of passivation has been defined using criteria derived from transient polarisation resistance measurements and large-scale polarisation, linear sweep voltammetry. In the majority of cases, oxygenation introduces instantaneous passivation of the mild steel on contact with the Bayer liquor. In comparison to de-oxygenated and aerated electrolytes, this rapid rate of passivation can lead to up to an order of magnitude reduction in the quantity of charge associated with metal dissolution over 20 h. Although relative rates of corrosion when passive are low and largely independent of the level of flow disturbance, dissolution rates when passive are somewhat larger at the higher Reynolds number. 相似文献
103.
Subcellular membranes were analyzed for their lipid composition and protein content at two developmental points representing
the third instar wandering larvae and prepupal stages ofDrosophila. At both stages, phosphatidylethanolamine (PE) and phosphatidylcholine (PC) were the major constituents with phosphatidylinositol
(PI), phosphatidylserine (PS), diphosphatidylglycerol (DPG) and phosphatidic acid (PA) being relatively minor components.
In total homogenates and in the nuclear-enriched fraction there was no significant difference in the phospholipid composition
of the wandering larvae and prepupae. In mitochondria only a significant increase in the minor component PS was observed in
the prepupae. In lysosomal membranes on the other hand, the relative abundance of the major components PE and PC increased
in the prepupae although the molar ratios of the two lipids remained almost constant. The fatty acid composition of the phospholipids
remained virtually unchanged in all of the fractions examined, including the lysosomes, and there was no evidence of lipid
peroxidation. With regard to cellular degeneration and the involvement of lysosomes, we conclude that mechanisms other than
gross modification of the lipid and/or lipid/protein ratio of their membranes are involved in the liberation of the acid phosphatase
contents. 相似文献
104.
Ayan Bandyopadhyay Debasis Ganguly Mandar Mitra Sanjoy Kumar Saha Gareth J.F. Jones 《Information Systems Frontiers》2018,20(5):925-932
Twitter (http://twitter.com) is one of the most popular social networking platforms. Twitter users can easily broadcast disaster-specific information, which, if effectively mined, can assist in relief operations. However, the brevity and informal nature of tweets pose a challenge to Information Retrieval (IR) researchers. In this paper, we successfully use word embedding techniques to improve ranking for ad-hoc queries on microblog data. Our experiments with the ‘Social Media for Emergency Relief and Preparedness’ (SMERP) dataset provided at an ECIR 2017 workshop show that these techniques outperform conventional term-matching based IR models. In addition, we show that, for the SMERP task, our word embedding based method is more effective if the embeddings are generated from the disaster specific SMERP data, than when they are trained on the large social media collection provided for the TREC (http://trec.nist.gov/) 2011 Microblog track dataset. 相似文献
105.
Catarina Rua Stephen J. Wastling Mauro Costagli Mark R. Symms Laura Biagi Mirco Cosottini Alberto Del Guerra Michela Tosetti Gareth J. Barker 《Magma (New York, N.Y.)》2018,31(2):257-267
Objective
Signal drop-off occurs in echo-planar imaging in inferior brain areas due to field gradients from susceptibility differences between air and tissue. Tailored-RF pulses based on a hyperbolic secant (HS) have been shown to partially recover signal at 3 T, but have not been tested at higher fields.Materials and methods
The aim of this study was to compare the performance of an optimized tailored-RF gradient-echo echo-planar imaging (TRF GRE-EPI) sequence with standard GRE-EPI at 7 T, in a passive viewing of faces or objects fMRI paradigm in healthy subjects.Results
Increased temporal-SNR (tSNR) was observed in the middle and inferior temporal lobes and orbitofrontal cortex of all subjects scanned, but elsewhere tSNR decreased relative to the standard acquisition. In the TRF GRE-EPI, increased functional signal was observed in the fusiform, lateral occipital cortex, and occipital pole, regions known to be part of the visual pathway involved in face-object perception.Conclusion
This work highlights the potential of TRF approaches at 7 T. Paired with a reversed-gradient distortion correction to compensate for in-plane susceptibility gradients, it provides an improved acquisition strategy for future neurocognitive studies at ultra-high field imaging in areas suffering from static magnetic field inhomogeneities.106.
Carlisle 2005 urban flood event simulation using cellular automata-based rapid flood spreading model
Yang Liu Gareth Pender 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2013,17(1):29-37
In this study, we propose a new method to apply the rapid flood spreading model (RFSM) using cellular automata (CA) to multiple inflows of Carlisle, UK. The purpose of the RFSM is to generate predictions of water depth and flood extent using less computer resource than required by two-dimensional shallow water equation models (SWEMs). To be useful the RFSM must produce predictions that are comparable with those obtained from SWEMs. This paper reports a validation data available to the date on an urban flood, collected in January 2005 after a major event in the city of Carlisle, UK. This demonstrates an agreement between the proposed RFSM and measured data. 相似文献
107.
Gareth Abrahams 《Architectural Theory Review》2019,23(3):363-379
AbstractWhat do we mean when we say that a building is an assemblage? To answer this question, we must first decide what we mean by ‘the assemblage’ and which areas of Deleuze and Guattari’s corpus we will use. In this paper I focus on one of two kinds of assemblage from A Thousand Plateaus: the machinic assemblage. Drawing on the third chapter of this core text, I show how and why this concept should be understood as complementary yet distinct from the often-neglected concept of the strata. I then illustrate these concepts through the architectural design process by discussing the creation of a physical and functional building, acts of (architectural) expression and as a contribution to one or more architectural languages. Using this insight, I argue that architecture provides us with a way to usefully illustrate and explore some of the complex and abstract concepts within Deleuze and Guattari’s philosophy. 相似文献
108.
Laser ablation in a model two-phase system 总被引:1,自引:0,他引:1
Gareth J. Williams Leonid V. Zhigilei Barbara J. Garrison 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2001,180(1-4):209-215
Short pulse laser ablation of a model two-component system has been simulated using a coarse-grained molecular dynamics (MD) model. A system with two disparate components (hard and soft) has been considered, based broadly on the properties of hard tissue. The existence of distinct regimes of material ejection has been identified and the processes leading to the ablation have been investigated. In the lower fluence regime gaseous particles of the soft component stream from the hard matrix but there is no ejection of the hard component. In the higher fluence regime chunks of the hard component are ejected simultaneously with the soft component. 相似文献
109.
Daniel Voß Wissem Zouaghi Mehran Jamshidifar Sebastian Boppel Cormac McDonnell James R. P. Bain Nils Hempler Graeme P. A. Malcolm Gareth T. Maker Maris Bauer Alvydas Lisauskas Adam Rämer Sergey A. Shevchenko Wolfgang Heinrich Viktor Krozer Hartmut G. Roskos 《Journal of Infrared, Millimeter and Terahertz Waves》2018,39(3):262-272
Aiming for non-destructive testing and security applications, we investigate transmission-mode imaging and spectroscopic sensing using terahertz (THz) pulses from a commercial optical parametric oscillator (OPO) in combination with THz detectors based on antenna-coupled field-effect transistors (TeraFETs). The Q-switched OPO generates quasi-continuous-wave THz pulses with a peak power of up to 1 W at a repetition rate between 12 and 90 Hz. The pulses are frequency-tunable between 0.7 and 2.6 THz with a typical linewidth of 50 GHz. We explore detection with fast GaN/AlGaN TeraFETs which hold the potential for multi-pixel and homodyne detection. 相似文献
110.
It is well known that substantial improvements can be obtained in difficult pattern recognition problems by combining or integrating the outputs of multiple neural classifiers. This paper analyses the performance of some combination schemes applied to a multi-hybrid neural system which is composed of neural and fuzzy neural networks. Essentially, the combination methods employ different ways to extract valuable information from the output of the experts through the use of confidence (weights) measures of the ensemble members to each class. An empirical evaluation in a handwritten numeral recognition task is used to investigate the performance of the presented methods in comparison with some existing combination methods. 相似文献