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44 results on '"Ko, C.H."'

17. Mg-induced increase of band gap in [Zn.sub.1-x][Mg.sub.x]O nanorods revealed by x-ray absorption and emission spectroscopy

Author

Chiou, J.W., Tsai, H.M., Pao, C.W., Chien, F.Z., Pong, W.F., Chen, C.W., Tsai, M.-H., Wu, J.J., Ko, C.H., Chiang, H.H., Lin, H.-J., Lee, J.F., and Guo, J.-H.

Subjects
Magnesium -- Spectra, Magnesium -- Chemical properties, Zinc oxide -- Spectra, Zinc oxide -- Chemical properties, Emission spectroscopy -- Analysis, Physics
Abstract

The effect of Mg doping in ZnO nanorods is examined X-ray absorption near-edge structure (XANES) and x-ray emission spectroscopy (XES) measurements. The XES and XANES spectra of O 2p states have shown that Mg doping raises the conduction-band-minimum and the band gap increases linearly with the Mg content.

Published
2008

24. Biochemical and molecular characterization of dopa-responsive dystonias in Hong Kong Chinese

Author

Mak, C.M., primary, Siu, T.S., additional, Tam, S., additional, Lam, C.W., additional, Chan, Y.W., additional, Chan, K.Y., additional, Chan, B., additional, Yau, E., additional, Hui, J., additional, Yeung, W.L., additional, Low, L.C., additional, Wong, V.C., additional, Lam, Y.Y., additional, Ko, C.H., additional, Cheng, W.W., additional, Yuen, Y.P., additional, Lee, H.C., additional, Siu, W.K., additional, and Tong, S.F., additional

Published
2010
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25. A comparative study on existing design rules for steel beams with circular web openings

Author

Ko, C.H., Chung, K.F., Ko, C.H., and Chung, K.F.

Abstract

Openings are often provided in the web of beams to allow flexible installation of building services of various sizes and shapes or to obtain attractive architectural appearance. Circular web opening has been traditionally analyzed as an equivalent rectangular opening in design methods derived from basic structural principles. This approach is simple but often very conservative. There is another approach which considers explicitly the tee sections with webs of varying depths above and below the web openings according to classical curve beam analysis. While this approach is less conservative, the calculation effort is considerable. In order to study the structural behaviour of steel beams with circular web openings, a finite element model with both material and geometrical non-linearity was established by Chung, Lui and Ko (2000) and a set of shear moment interaction curves for steel beams with large circular web openings were also established. This paper presents the results of a comparative study on a number of design methods against the finite element results. Both the shear moment interaction curves and the load carrying capacities of steel beams with large web openings are presented and discussed. Furthermore, a simple and yet efficient design procedure is proposed using an equivalent octagonal web opening and good comparison with the finite element results is achieved. The adoption of equivalent octagonal openings allows simple and easy incorporation of other opening shapes together with instability of web posts in steel beams with multiple web openings. Furthermore, it is expected to develop a set of harmonized design rules to cover the design of steel beams with single and multiple web openings of arbitrary shapes for general application.

Published
2000

26. Hot carrier photoluminescence in InN epilayers

Author

Yang, M.D., primary, Chen, Y.P., additional, Shu, G.W., additional, Shen, J.L., additional, Hung, S.C., additional, Chi, G.C., additional, Lin, T.Y., additional, Lee, Y.C., additional, Chen, C.T., additional, and Ko, C.H., additional

Published
2007
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32. De novo mutation in the mitochondrial tRNALeu(UUR) gene (A3243G) with rapid segregation resulting in MELAS in the offspring.

Author

Ko, C.H., Lam, C.W., Tse, P.W.T., Kong, C.K., Chan, A.K.H., Wong, L.J.C., Tse, P W, Chan, A K, and Wong, L J

Subjects
*GENETIC disorders, *MITOCHONDRIAL membrane abnormalities, *TRANSFER RNA
Abstract

A 14-year-old Chinese boy with a normal perinatal and early developmental history presented at 5 years of age with migraine, intractable epilepsy, ataxia, supraventricular tachycardia, paralytic ileus and progressive mental deterioration. Computerized tomography revealed multiple cerebral infarcts in the parieto-occipital region without basal ganglial calcification. Magnetic resonance imaging showed increased signal intensity in T2 weighted images in the same regions. A cerebral digital subtraction angiogram was normal. Venous lactate, pyruvate, lactate to pyruvate ratio and cerebrospinal fluid lactate were elevated. Muscle biopsy did not reveal any ragged red fibres; dinucleotide-tetrazolium reductase activity was normal. Mitochondrial DNA analysis detected an adenine to guanine mutation at nucleotide position 3243 of tRNALeu(UUR). All four tissues analysed demonstrated heteroplasmy: leucocyte 56%, hair follicle 70%; buccal cell 64%; muscle 54%. The mother and brother of the proband, both asymptomatic, were also found to have a heteroplasmic A3243G mutation in the leucocytes, hair follicle and buccal cells. Other members of the maternal lineage, including the maternal grandmother, did not have the mutation. This report describes a patient with mitochondrial encephalopathy, lactic acidosis, stroke-like episodes, who presented with multisystem involvement. The absence of ragged red fibres in muscle biopsy did not preclude the diagnosis. Mutational analysis of mitochondrial DNA conveniently confirmed the diagnosis of the disorder. A de novo mutation is demonstrated in this family. [ABSTRACT FROM AUTHOR]

Published
2001
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33. Optimization of BiFeO3MFIS Capacitors Doped Niobium by Using Taguchi Method

Author

Lin, K.C., Ko, C.H., Twu, M.J., Juan, P.C., Sekiguchi, H., and Chou, C.H.

Abstract

In this study,MFIS (Metal/Ferroelectric/Insulator/Semiconductor) capacitors whose structure is Al/BFO+Nb/HfO2/p-Si are investigatedby using Taguchi Method. The effects of leakage current, memory window, and signal-to-noise ratio (S/N ratio) are discussed by different process conditions. As a result, the leakage current and memory window indicate the better performance on th same process condition. The better conditions of this MFIS capacitoroccur in rapid thermal annealing (RTA) at 700°C, 5W direct current (DC) power of Nb sputtering and 15 of argon-to-oxygen ratio for laekage current and memory window.Oxygen vacancies were reduced bydoping niobium (Nb) that Nb ions replace ferrum (Fe) ions with RTA at 700°C. The more Nb dopesthe more Nb ions replace Fe ions. Butthe excessive Nb induces to increase the leakage current and reduce the memory widow.

Published
2013
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34. P033 * Evaluation of myocardial function in patients with chronic stable angina and apparent normal ventricular function (tissue doppler study before and after PCI)

Author

Rashid, H., Abdel-Moniem, A., Email, S., El-Batran, M., Rashid, H., Mansour, H., Mahmoud, S., Ashour, Z., Mustafa, S., Khodeer, S.A., Abdu-Allah, A.M., Al-Assal, M., Rashid, H.K., Ghosh Dastidar, A., Garg, P., West, J., Muthusamy, R., Gunn, J., Zhu, F., Lee, A., Chee, Y.E., Li, Z.J., Kang, C.S., Chen, Z.Y., Zhang, Y.X., Zhao, Z.X., Song, Q., Rong, Y., Bao, W., Shan, Z.L., Rong, S., Wang, D., Yao, P., Liu, L.G., Zhu, L.X., Ho, S.C., Ruan, G.Q., Xie, Q., Sit, J.W.H., Yang, Y.L., Chan, M.C.H., Hu, M., Chan, T.Y.K., Tomlinson, B., Wu, H.S., Wang, L.S., Qin, J., Wong, T.T., Heng, P.A., Yu, C.M., Luis, S.A., Luis, C.R., Habibian, M., Courtney, A., Hamilton-Craig, C., Strugnell, W., Poon, K., Slaughter, R., Raffel, O.C., Raffel, O.C., Luis, S.A., Hansen, M., Slaughter, R., Hamilton-Craig, C., Liang, Y., Bai, Y., Chen, T., Feng, G.X., Yang, Y.M., Wang, X.Y., Yang, Y.J., Zhu, J., Al-Mohammadi, M., Hersi, A., Alhabib, K.F., Alsheikh-Ali, A.A., Sulaiman, K., Alfaleh, H., Alsaif, S., Almahmeed, W., Asaad, N., Amin, H., Al-Motarreb, A., Al-Suwaid, J., Blanco, J.R.F., Velasco, A.B., Mancera, J., Francisco, A., CA, Zhuravlyova, L., Lopina, N., Song, H.H., Xu, S.H., Huang, M.Z., Xu, C.S., Xie, L.D., Ko, B., Cameron, J., Seneviratne, S., Leung, M., Antonis, P., Koutsoubos, J., Malaiapan, Y., Meredith, I., Capros, N., Istrati, V., Matcovschi, S., Dumitras, T., Istrati, S., Nicolenco, I., Hotineanu, R., Manea, D., Gherman, O., Hsiung, M.C., Ko, C.H., Wei, J., Tung, T.H., Graham, C.A., Chan, J.W.M., Rotherary, K.R., Rainer, T.H., Yan, B., Liu, M., Huang, X.R., Li, R.J., Lam, Y.Y., and Yu, C.M.

Abstract

Objective: It has been reported that impaired left ventricular longitudinal function may precede circumferential ventricular dysfunction in patients with coronary artery disease. This study is to determine the impact of PCI on myocardial function assessed by tissue Doppler echocardiography in patients with chronic stable angina. Method: Twenty-five consecutive patients with chronic stable angina and preserved systolic LV function (EF%> 50%) underwent PCI were studied by pulsed wave tissue Doppler at different time intervals before and after PCI. All patients were subjected to the following: Full history and physical examination, ECG, Echocardiography before PCI to evaluate baseline systolic & diastolic function as well as 1 day&6 weeks after intervention, and pulsed-wave tissue Doppler Echo was done before PCI, as well as 1 day&6 weeks after intervention to detect mitral and tricuspid inflow velocities, including E and A wave peak velocities (in centimeters per second). Result: We found that systolic myocardial peak velocities improved significantly after PCI in the septal, lateral, anterior, posterior, and inferior walls(P < 0.001 for each) by tissue Doppler imaging while non detected by conventional Echo. There was a significant increase of EA ratio at anterior angle of mitral valve annulus and lateral angle of tricuspid valve annulus.(p= 0.02 for both),also The right ventricle showed significant improvement in tissue Doppler measures of systolic function, early, and late diastolic function 1day &6 weeks after PCI compared with baseline values (P< .001),While non detected by conventional Echo. Conclusion: Tissue Doppler Echo. is a noninvasive and widely available diagnostic technique that allows the sensitive detection of right & left myocardial dysfunction.

Published
2012
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