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101.
102.
P. Yeo R. Arès S. P. Watkins G. A. Horley P. O’Brien A. C. Jones 《Journal of Electronic Materials》1997,26(10):1174-1177
We report the use of a new precursor, trisneopentylgallium (NPG) for the growth of GaAs by atomic layer epitaxy (ALE). In
contrast to most other alkyl gallium precursors such as triethylgallium, which decompose via a β-hydride elimination mechanism,
this compound undergoes homolysis similar to that of trimethylgallium (TMGa), the normal choice as an ALE precursor. Clear
self-limiting growth behavior similar to that of TMGa was observed over a reasonably wide range of growth conditions (430–500°C).
Carbon incorporation was not significantly reduced compared with TMGa suggesting that the adsorbed neopentyl radicals undergo
decomposition to result in a methyl terminated surface identical to that obtained for growth with TMGa. 相似文献
103.
Yasantha Athukorala Ki‐Wan Lee Eun‐Ju Park Moon‐Soo Heo In‐Kyu Yeo Young‐Don Lee You‐Jin Jeon 《Journal of the science of food and agriculture》2005,85(14):2341-2348
The antioxidant activity of an extract of Grateloupia filicina was evaluated using linoleic acid and fish oil as substrates in an induct period at 65 °C. Furthermore, the algal extract was subjected to comet assay to evaluate its protecting ability for H2O2‐induced DNA damage in rat lymphocytes. Progression of oxidation was examined using weight gain, peroxide value (PV), 2‐thiobarbituric acid reactive substances and conjugated diene data. Effectiveness of the extract at 0.03 and 0.05% levels was superior to that of α‐tocopherol at 0.01% and the activity of 0.05% extract was higher than that of butylated hydroxyanisole and butylated hydroxytoluene at 0.01%. Also, the algal extract significantly inhibited H2O2 induced DNA damage in comet assay. The maximum DNA damage inhibition (68.9%) was recorded from the 50 µg ml−1 alga extract when the rat lymphocyte cells were treated with 50 µM H2O2. Copyright © 2005 Society of Chemical Industry 相似文献
104.
Autofocusing for tissue microscopy 总被引:12,自引:0,他引:12
This paper describes the implementation of autofocusing for tissue microscopy. We first investigate the suitability of several criterion functions for the evaluation of image sharpness. Since tissue sections are invariably stained, we also discuss the selection of the colour component on which autofocusing will be performed. In tissue microscopy, where a section generally comprises multiple layers, it is often not possible to obtain an image that is well focused over the field of view because of the limited depth of field of the objective. We describe focus enhancement algorithms, closely related to the autofocus system, which may be employed to obtain an entirely sharp image. 相似文献
105.
Automatic parsing and indexing of news video 总被引:9,自引:0,他引:9
Automatic construction of content-based indices for video source material requires general semantic interpretation of both images and their accompanying sounds; but such a broadly-based semantic analysis is beyond the capabilities of the current technologies of machine vision and audio signal analysis. However, if one can assume a limited and well-demarcated body of domain knowledge for describing the content of a body of video, then it becomes easier to interpret a video source in terms of that domain knowledge. This paper presents our work on using domain knowledge to parse news video programs and to index them on the basis of their visual content. Models based on both the spatial structure of image frames and the temporal structure of the entire program have been developed for news videos, along with algorithms that apply these models by locating and identifying instances of their elements. Experimental results are also discussed in detail to evaluate both the models and the algorithms that use them. Finally, proposals for future work are summarized. 相似文献
106.
Kaixue Ma Jianguo Ma Jianbo Sun Jianmin Miao Manh Anh Do Kiat Seng Yeo 《Microwave and Wireless Components Letters, IEEE》2005,15(7):478-480
A new miniaturized ground ring guided microstrip patch filter developed on the silicon wafer using micromachined technology is reported. The ground shunt can be used to lower the operating frequency up to one-third as compared to the traditional patch resonator. The size of the designed band pass filter operating in 5.17 GHz is only 8.7 mm/spl times/2.9 mm. 相似文献
107.
Ozanyan K.B. Yeo T.L. Hindle F.P. Poolton N.R.J. McCann H. Tan K.L. 《IEEE sensors journal》2004,4(5):681-690
We report on an optical fiber probe, coupled to a 404-nm laser diode, as a fluorescence sensor for monitoring of commercial gasolines. The principle of operation of the sensor is based on quantifying the intensity of the Stokes-shifted fluorescence from some of the heavier polycyclic aromatic hydrocarbons C/sub x/H/sub y/,(x,y) /spl ges/ (14,10) present in gasolines as minor constituents. The normalized efficiency of the optical fiber probe, as a function of its geometry, is calculated in the cases of single-fiber and parallel dual-fiber designs. The spatial and temporal resolutions achievable by the sensor are discussed as a function of design parameters The performance of the sensor is investigated experimentally for commercial gasolines in the liquid and gas phase. The optimal excitation wavelength for such sensors is investigated in the range of 350-400 nm. The linear sensitivity to vapor concentrations of retail gasoline fuel is demonstrated in the range of 4%-125% of combustion stoichiometry at 10 bar and 180/spl deg/C. Statistical processing of the data from the sensor allows distinction to be made between different forecourt gasoline suppliers, as well as fuel varieties (unleaded, low sulfur, etc.). 相似文献
108.
Smillie Luke D.; Yeo Gillian B.; Furnham Adrian F.; Jackson Chris J. 《Canadian Metallurgical Quarterly》2006,91(1):139
The authors evaluate a model suggesting that the performance of highly neurotic individuals, relative to their stable counterparts, is more strongly influenced by factors relating to the allocation of attentional resources. First, an air traffic control simulation was used to examine the interaction between effort intensity and scores on the Anxiety subscale of Eysenck Personality Profiler Neuroticism in the prediction of task performance. Overall effort intensity enhanced performance for highly anxious individuals more so than for individuals with low anxiety. Second, a longitudinal field study was used to examine the interaction between office busyness and Eysenck Personality Inventory Neuroticism in the prediction of telesales performance. Changes in office busyness were associated with greater performance improvements for highly neurotic individuals compared with less neurotic individuals. These studies suggest that highly neurotic individuals outperform their stable counterparts in a busy work environment or if they are expending a high level of effort. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
109.
I.W. Yeo M.H. de Freitas R.W. Zimmerman 《International Journal of Rock Mechanics and Mining Sciences》1998,35(8):1051-1070
The results of experiments using radial and unidirectional flow in a carefully described single rough aperture are reported and compared with numerical predictions. Aperture replicas of a natural sandstone fracture were made at 0, 1 and 2 mm shear displacements using silicone rubber, with a reproducibility of better than 2%. The experimental arrangement permitted shear displacement to be obtained without causing damage to the two displaced surfaces, which thus retained their original (and essentially matching) geometry. Both the number of contact points and the fractional contact area decreased with increasing shear displacement. With increasing shear displacement, mean aperture and standard deviation increased and the ratio of standard deviation to mean aperture increased slightly. Semivariogram studies indicated that as shear displacement increased in the direction normal to the roughness ridges, the aperture distribution became more closely correlated in the direction parallel to the roughness ridges than in the shear direction. Flow tests showed that with increasing shear displacement, the fracture became heterogeneous and anisotropic and became more permeable in the direction perpendicular to the shear displacement than in the direction parallel to the displacement. Simulations were made of flow through the fracture using the Reynolds equation and the actual aperture distribution; the measured hydraulic apertures were generally about 20% lower than those measured numerically. 相似文献
110.
Hill Dina E.; Yeo Ronald A.; Campbell Richard A.; Hart Blaine; Vigil Janet; Brooks William 《Canadian Metallurgical Quarterly》2003,17(3):496
This study compared magnetic resonance imaging size differences in several brain regions and neurocognitive function in a group of male and female children with attention-deficit/hyperactivity disorder (ADHD) with no comorbid learning disorders with a normal control group of children. The ADHD group demonstrated smaller total brain, superior prefrontal, and right superior prefrontal volumes, as well as significantly smaller areas for cerebellar lobules I-V and VIII-X, total corpus callosum area, and splenium. No group differences were observed for the inferior prefrontal, caudate, or cerebellar volumes, or for the area of cerebellar lobules VI-VII. In the ADHD group but not in the control group, greater right superior prefrontal volume predicted poorer performance on a test of sustained attention. Patterns of brain abnormality did not differ in male and female children with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献