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41.
Wen-Yan Yin Le-Wei Li Tat-Soon Yeo Mook-Seng Leong 《Electromagnetic Compatibility, IEEE Transactions on》2000,42(4):330-338
A generalized mathematical procedure is developed for investigating a TEz-polarized plane wave penetration through two-dimensional (2-D) multilayered cylindrical cavity-backed apertures. The mathematical treatment is based on the direct integral equation technique combined with the Galerkin's procedure. Both the near- and far-zone field solutions to such a multiple coupling system are obtained in an analytical form. By taking the aperture edge effects into account, the magnetic currents on the surrounded multiple apertures are expanded in terms of a series of Chebyshev polynomials of the first kind. Furthermore, parametric studies are performed to show the variation of the penetrated near-zone magnetic field in various cylindrical cavity-backed apertures with the aperture number and geometrical sizes 相似文献
42.
43.
H.Y. Li K.C. Leong L.W. Jin J.C. Chai 《International Journal of Heat and Mass Transfer》2010,53(23-24):5209-5222
The transient behavior of flow boiling in vertical porous channels is numerically studied in this paper. The velocity and temperature fields under different parameters for both aiding and opposing flows are investigated. Distinctly different flow and heat transfer features are observed in the comparison of aiding and opposing flows. An analysis of liquid saturation along the heated wall indicates that the minimum liquid saturation for aiding flow is located at the tail of the heated section, whereas for opposing flow, it is within the heated section and shifts upstream with the increase of Rayleigh number and decrease of Peclet number. 相似文献
44.
CC Leong JV Marley S Loh N Milech BW Robinson MJ Garlepp 《Canadian Metallurgical Quarterly》1997,71(3):476-482
A 56-year-old female with rheumatoid arthritis was admitted because of bilateral hip pain. In a few months of her hospitalization, a relatively abrupt renal dysfunction was emerged besides complement breakdown, and renal biopsy revealed crescentic glomerulonephritis. Immunofluorescence study showed peripheral granular deposits of IgG, IgM, and C3 in the glomeruli. Cresents were predominantly composed of macrophages and glomerular epithelial cells. Amyloid nephropathy, renal vasuculitis, and association of other collagen vascular diseases were negligible for the causative factor. It was suggested that immune complexes were formed in the glomeruli, in which both humoral and cellular immune responses were to be induced, that brought cescents formation in the lesions. Crescentic glomerulonephritis in patients with rheumatoid arthritis is rare and a possible pathogenetic mechanisms involved in the development of renal dysfunction are discussed with the special reference to immune complex-induced inflammation. 相似文献
45.
Qiang Zeng Chee Leong Teo Brice Rebsamen Etienne Burdet 《IEEE transactions on neural systems and rehabilitation engineering》2008,16(2):161-170
This paper describes a novel robotic wheelchair, and reports experiments to evaluate its efficiency and understand how human operators use it. The concept at the heart of the collaborative wheelchair assistant (CWA) is to rely on the user's motion planning skills while assisting the maneuvering with flexible path guidance. The user decides where to go and controls the speed (including start and stop), while the system guides the wheelchair along software-defined guide paths. An intuitive path editor allows the user to avoid dangers or obstacles online and to modify the guide paths at will. By using the human sensory and planning systems, no complex sensor processing or artificial decision system is needed, making the system safe, simple, and low-cost. We investigated the performance of the CWA on its interaction with able-bodied subjects and motion efficiency. The results show that path guidance drastically simplifies the control. Using the CWA, the wheelchair user needs little effort from the first trial, while moving efficiently with a conventional wheelchair requires adaptation. 相似文献
46.
Le-Wei Li Xiao-Kang Kang Mook-Seng Leong Pang-Shyan Kooi Tat-Soon Yeo 《Microwave Theory and Techniques》2001,49(3):532-541
Dyadic Green's functions (DGFs) and their scattering coefficients are formulated in this paper for defining the electromagnetic fields in multilayered spheroidal structures. The principle of scattering superposition is applied, in a similar form of the DGF in an unbounded medium under spheroidal coordinates, the scattering DGFs due to multiple spheroidal interfaces are expanded in terms of the spheroidal vector wave functions. For the lack of general orthogonality of the spheroidal radial and angular functions, the Green's dyadics are expressed in a different way where the coordinate unit vectors are also combined in the construction, as compared with the conventional form of vector wave eigenfunction expansion. The matrix equation systems satisfied by the coupled scattering (i.e., reflection and transmission) coefficients of the DGFs are obtained so that these coefficients can be solved uniquely. The DGFs can be employed to investigate effects of spheroidal radomes used to protect the airborne or satellite antenna systems and of handy phone radiation near the spheroid-shaped human head, and so forth. Numerical calculations about the applications of the formulated multilayered DGFs are presented in part II of this paper 相似文献
47.
Writing Psychology of reading has given John Downing and this writer a great deal of self-doubts and self-criticisms. This is particularly so in a field which is so vast and complex and where there is a high level of productivity. We are thus appreciative of the insightful review of our volume by Linda Siegel (Canadian Psychology, 1985, 26, pp. 300-301, see record 2007-08971-001). We agree with the comments on the "complexities of definitional issues" and the need to amplify on comprehending. This latter endeavour, to misquote Edmund Huey, "would almost be the acme of a psychologist's achievements." Lest Downing and Leong be misunderstood, I would like to clarify one main point raised in the review. We state that "the discredited achievement or learning quotient should be laid to rest" (p. 306). If some psychometric tests must be used, they must meet all the technical requirements. In particular, these screening devices need to be "supplemented by individual diagnosis of children for appropriate educational placement and programming" (p. 306). Elsewhere I have elaborated on this two-tier approach of the more quantitative psychometric assessment followed by the more qualitative cognitive-developmental diagnosis (Leong, 1985, in press). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
48.
A study of sex and acculturation differences in occupational values among a group of Chinese-American children (5th and 6th graders) found that money and task satisfaction were very important values, whereas object orientation and solitude were quite unimportant. The high-acculturation children valued self-realization more than the low-acculturation children. Some sex differences in occupational values were also found among this group of children: boys valued object orientation, self-realization, and ideas–data more than did girls, and girls valued altruism more than did boys. The counseling and research implications of the findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
49.
The Okinawan folks in Japan use Ficus pumila L. as a beverage or herbal medicine to treat diabetes and high blood pressure. Four flavonoid glycosides were isolated and identified as rutin (1 and 3), apigenin 6-neohesperidose (2), kaempferol 3-robinobioside (4) and kaempferol 3-rutinoside (5). Among these compounds, rutin exhibited the strongest antioxidant activity in DPPH radical scavenging assay and superoxide radical inhibition assay. The preparation of Ooitabi leaves in water provide sufficient amount of flavonoid glycosides to the Okinawan although 50% of aqueous ethanol extracted these flavonoid glycosides more effectively. These results show the potential of Ooitabi leaves as a natural source of antioxidant for health management. 相似文献
50.
Le-Wei Li Mook-Seng Leong Yeqin Huang 《Antennas and Propagation, IEEE Transactions on》2001,49(1):84-90
Although numerical solutions to the electromagnetic scattering by an arbitrarily shaped object have been obtained using Waterman's (1971) T-matrix method (TMM), the general electromagnetic radiation due to an antenna of a three-dimensional (3-D) current distribution in the presence of an arbitrarily shaped object has not been well considered. In this paper, the technique of surface integral equations has been employed; and as a result, a terse and analytical representation of the dyadic Green's functions (DGFs) in the presence of an arbitrarily shaped dielectric object is obtained for the antenna radiation. In a form similar to that associated with the electromagnetic radiation in the presence of a dielectric sphere, the DGFs inside and outside of the object of arbitrary shape are expanded in terms of spherical vector wave functions. However, their coefficients are no longer decoupled due to the arbitrary surface of a 3-D object. The coupled coefficients are then determined using the surface integral equation approach, in a fashion similar to that in the T-matrix method. To confirm the applicability and correctness of the approach in this paper a dielectric sphere, as a special case, is utilized as an illustration. It is found that exactly the same expressions as in the rigorous analysis for the inner and outer spherical regions of the object are obtained using the different approaches. As applications of the approach in this paper, radiation problems of an electric dipole in the presence of superspheroids and rotational parabolic bodies are solved 相似文献