11 results on '"Yu Ko"'
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2. Canadian Nurses’ Perspectives on Prostate Cancer Support Groups
- Author
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Yu Ko, Wellam F., Oliffe, John L., Han, Christina S., Garrett, Bernie, Henwood, Tim, Tuckett, Anthony G., and Sohrevardi, Armin
- Published
- 2016
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3. Lignin-g-polycaprolactone as a form-stable phase change material for thermal energy storage application
- Author
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Lee, Johnathan Joo Cheng, Sugiarto, Sigit, Ong, Pin Jin, Soo, Xiang Yun Debbie, Ni, Xiping, Luo, Ping, Hnin, Yu Yu Ko, See, Josephine Si Yu, Wei, Fengxia, Zheng, Rongyan, Wang, Pei, Xu, Jianwei, Loh, Xian Jun, Kai, Dan, and Zhu, Qiang
- Abstract
Lignocellulosic biomass is mostly found in municipal waste by-products, and a major component of this waste is made up of the macropolymer, lignin, which is usually hard to valorize and causes environmental pollution issues. Valorizing lignin through their hydroxy groups has been intensively researched for various purposes and therefore, is a promising green alternative sustainable material. Lignin can be used as a composite phase change material (PCM) as compared to conventional organic and inorganic PCMs. In this work, Lignin-g-polycaprolactone (PCL) was prepared by grafting of alkaline lignin with PCL via the ring-opening polymerization reaction using triazabicyclodecane (TBD) as an organic catalyst. A comparison study of the physically mixed lignin with PCL, and Lignin-g-PCL was conducted to investigate the differences in their thermophysical properties. The chemical structure of Lignin-g-PCL was verified by nuclear magnetic resonance (NMR), and the products were separated by molecular weight via gel permeation chromatography (GPC), revealing the PCL was successfully grafted onto the lignin via the ring-opening polymerization. Differential scanning calorimetry (DSC) results showed that the phase transition temperature of Lignin-g-PCL was approximately 51.3 °C, with a latent heat value of 61.16 J/g. Thermal cycling test up to 100 cycles also revealed its thermal stability and reliability in applications. Thermogravimetric analysis (TGA) confirmed its thermal degradation temperatures at 300–400 °C which was much higher than its melting temperature 51.3 °C. Lignin-g-PCL also showed superior form stability in contrast to both its pristine counterparts and physically mixed samples based on a form stability and leakage test. Lastly, Lignin-g-PCL demonstrated its potential application as a PCM via a thermal absorption test where its solid-solid phase change was most apparent during cooling and was able to exhibit thermoregulation of about 2 min at near body temperature of about 39 °C.
- Published
- 2022
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4. Minimizing maximum tardiness in single FMS machine scheduling with tool changes
- Author
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Lin, Kai-Yung and Chung, Yu-Ko
- Abstract
Flexible Manufacturing System(FMS) is a programmable automation system that efficiently accommodates product variations and small-lot production capability. Tool change is an important issue for FMS tool management. Previous literature on tool management addresses this issue, but assumes that the change is due only to part mix. In practice, however, most tool changes are the result of tool wear. This study considers the problem of scheduling a set of jobs on a single FMS where the cutting tool is subject to wear, aiming to minimize the maximum tardiness. Two mixed binary integer programming models were developed to solve this problem optimally. We developed the heuristic method to compute result to demonstrate the efficiency of the models.
- Published
- 2009
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5. A Model of Users' Satisfaction with Taiwan's Government Website
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Chung, Yu-Ko, Sheu, Liang-Chyau, and Chien, Sarina Hui-Lin
- Abstract
Taiwan's Government web portal has been the sole communication link between citizens and E-Government since being launched in 2002 to provide citizens with government-related information promptly via effective classification. The assessment of the service quality and citizens' satisfaction with E-Government has rarely been explored. The present study explored how the service quality of E-Govemment subsequently affects the users' psychological and behavioral responses. A structural model was proposed that contained four constructs: service quality, service value, users' satisfaction, and behavioral intention as well as their interrelations. A survey was used to collect users' ratings. Structural equation modeling was applied to verify the factor analysis of the obtained data and fit of a model. Analyses indicated adequate fit of model as follows: E-Government service quality → service value → users' satisfaction → behavioral intention.
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- 2007
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6. A Silicon Oxide Hard Coating Deposited on Flexible Substrate by TMS - PECVD System
- Author
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Liu, Day Shan, Liao, Yu Ko, Wu, Cheng Yang, Juang, Fuh Shyang, and Lee, Ching Ting
- Abstract
A hard coating silicon oxide film was deposited on flexible substrates by a PECVD system. Tertramethylsilane (TMS) and oxygen were employed as raw materials. Surface roughness and hardness of these films deposited under various TMS/O2 gas flow ratio, rf power and chamber pressure were investigated. At adequate fabricated conditions, the original surface roughness of PMMA (~ 3.36 nm) and PC (~ 1.38 nm) substrates was markedly flatted to 1.52 and 0.39 nm, respectively. Meanwhile, the surface hardness of coated PMMA and PC substrates was also enhanced to 6.077 GPa and 3.978 GPa, respectively. The hardness of silicon oxide film deposited by TMS-PECVD system was superior to silicon oxide films prepared from e-beam evaporation and dipping technologies.
- Published
- 2006
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7. Synthesis and microstructure of metal oxide thin films containing metal nanoparticles by liquid phase deposition (LPD) method
- Author
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Deki, S., Yu Yu Ko, Hnin, Fujita, T., Akamatsu, K., Mizuhata, M., and Kajinami, A.
- Abstract
Abstract:: Au nanoparticles dispersed SiO
2 -TiO2 composite films have been prepared by a novel wet process, Liquid Phase Deposition (LPD) method. The composite films were characterized by XRD, XPS, TEM, ICP, SEM and UV-VIS absorption spectroscopy. The results showed that the SiO2 -TiO2 composite films containing AuIII and AuI ionic species were co-deposited from a mixed solution of ammonium silicofluoride, ammonium hexafluorotitanate, boric acid and tetrachloroauric acid. The heat treatment induced the reduction of Au ions and formation of Au nanoparticles in the film. TEM observation revealed that the Au nanoparticles with 5-10 nm in diameter were found to be dispersed uniformly in the SiO2 -TiO2 matrix. The optical absorption band due to the surface plasmon resonance of dispersed Au particles were observed at the wavelength of 550 nm and shifted toward longer wavelength with increasing heat treatment temperature.- Published
- 2001
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8. Principle of real-object scaling, projection and spatial stress solution of a block in a rock mass
- Author
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Sun, Yu-ko and Ku, Hsun
- Abstract
An important subject which engineering geology and rock mechanics deals with is the study of the origin of structure surfaces in rock masses and its combining law, determine the mutual relation the structure body bears with the structure surface and the acting force such as gravity, residual tectonic stress and engineering forces etc., which are directly affecting the stability of rock engineering. Therefore, through field work, the nature, occurrence, development degree as well as distribution of the structure surface in a rock mass can be observed, analysed and summed up. It is necessary to make a scheme showing the relationship between structure surfaces, the relationship between structure surface and free surfaces due to excavation, as well as the relationship between angle distance and basic geometrical shapes of a structure body. For this purpose, real-object scaling projection is suggested. Un important sujet dont s’occupent la géologie de l’ingénieur et la mécanique des roches, l’étude de l’origine des discontinuités structurales dans les massifs rocheux et des lois de leurs associations, contribue à la détermination des relations de ces discontinuités avec les forces dues à la gravité, aux contraintes tectoniques résiduelles, aux travaux humains, etc., qui affectent directement la stabilité des travaux sur roches. Ainsi, par l’observation sur le terrain, la nature des discontinuités structurales, leur occurrence, l’importance de leur développement, aussi bien que leur répartition dans un massif rocheux peuvent être observées, analysées et répertoriées. Il est nécessaire de schématiser les relations entre les surfaces de discontinuités, et entre surfaces de discontinuité et surfaces libres dues à l’excavation, ainsi que les relations géométriques intrinsèques de l’objet étudié. C’est dans ce but que les auteurs proposent une représentation d’un objet réel à l’échelle.
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- 1978
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9. Use of a Binary Mixture of Quaternary Ammonium Salts in Fluorometric Determination of Glycosaminoglycans
- Author
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Kakehi, Kazuaki, Maeya, Yu-ko, Miki, Yasuyoshi, Oda, Yasuo, and Hayase, Shozo
- Abstract
The concentration of glycosaminoglycans in an aqueous solution was determined by observing the fluorescent intensity of the ion of 2-hexadecyl-9H-pyrido[4,3b]indole at 450 nm by irradiating 253-nm light after dissolution of the insoluble salt in ethanol, which was formed by the reaction between a solution of a sample of glycosaminoglycan and an aqueous solution of the binary mixture of fluorescent 2-hexadecyl-9H-pyrido[4,3b]indolium bromide and hexadecyl pyridinium chloride. The fluorescent quaternary ammonium salt, which was slightly soluble in water, was solubilized in water by forming mixed micelles with a nonfluorescent soluble quaternary ammonium salt. The present method showed good linearity for the calibration curves between 5 and 1000 μg/ml in all samples of glycosaminoglycan except keratan sulfate. The relative standard deviation in determination was less than 3% for the whole calibration range.
- Published
- 1997
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10. The relation between impaired response of norepinephrine to exercise and peripheral 123I-MIBG imaging in chronic heart failure
- Author
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Takaya, Tsuchida, Nagaharu, Fukuma, Noriko, Aisu, Yu-Ko, Kato, Kazuyo, Kato, Kousuke, Mabuchi, and Teruo, Takano
- Abstract
Background:Past report showed that 123I-MIBG washout rate of heart correlates plasma norepinephrine concentration. But, it is unknown that whether the response of norepinephrine to exercise relates sympathetic nerve function innervating peripheral vessels using 123I-MIBG imaging.Method:The population of this study consists of 12 patients (10 male and 2 female, 48 ± 13 y, EF < 45%) with chronic heart failure. All subjects underwent cardiopulmonary exercise test and measurement of early (20 min) and late (4 h) MIBG uptake, leg to brain ratio (L/B), and washout rate (WR) from early to delayed images. Arterial blood was sampled at rest and at peak exercise to assess norepinephrine concentration. All subjects were separated into two groups on the basis of L/B; low L/B (L/B < 1.05, n=6) and normal L/B (L/B1.05, n=6).Result:1) Between the two groups, we didn't recognize significant difference in the parameter such as age, sex, EF, etiology and peak VO2. 2) Arterial norepinephrine concentration at rest indicated no significant difference between the two groups (385 ± 145 vs. 421 ± 145 pg/ml). However, the increment of norepinephrine concentration from rest to peak exercise in normal L/B group showed a significant high value in comparison with low L/B group(775 ± 366 vs. 392 ± 120 pg/ml).Conclusion:It is suggested that low L/B as decrement of MIBG uptake to leg represents disturbing sympathetic nerve function and reducing norepinephrine release during exercise.
- Published
- 2004
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11. Oxidative stress limits exercise tolerance through impairment of sympathetic function
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Kazuyo, Kato, Nagaharu, Fukuma, Yu-Ko, Kato, Noriko, Aisu, Takaya, Tuchida, Kousuke, Mabuti, and teruo, Takano
- Abstract
Purpose:Recent reports demonstrated that oxidative stress influenced pathogenetic processes and that impairment of sympathetic function limited exercise tolerance in patients with heart failure. Therefore, we examined whether enhancement of oxidative stress influenced to exercise tolerance through sympathetic function. Methods:Twenty one patients after myocardial infarction (61 ± 7 y/o) underwent symptom-limited cardiopulmonary exercise test. We measured plasma 8isoPGF2 as an oxidative stress marker and norepinephrine concentration (NE). We calculated the ratio of increment in hear rate to increment in NE from rest to peak exercise as an index of sympathetic responsiveness (deltaHR/logdeltaNE). This study population was divided into 2 groups; low peakVO2 group (<18ml/min/kg, n=9) and normal peakVO2 group (<18ml/min/kg, n=12). Results:1) Plasma 8isoPGF2 was higher in low peakVO2 group than in normal peakVO2 group (21.4 ± 9.2 vs. 14.8 ± 3.7 pg/ml, p < 0.05). 2) The increment in NE (logdeltaNE) was significantly lower in low peakVO2 group than in normal peakVO2 group (8.7 ± 2.1 vs. 7.6 ± 2.0, p < 0.05). 3) deltaHR/logdeltaNE correlated negatively with plasma 8isoPGF2 (r=−0.482, p < 0.05). Conclusion:The increase of oxidative stress in heart failure influenced exercise tolerance, correlated with responsiveness of sinus node for NE. It is suggested that sympathetic dysfunction injured by oxidative stress limits exercise capacity in patients with heart failure.
- Published
- 2004
- Full Text
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