62 results on '"Che-Min Lin"'
Search Results
2. P‐20: 32‐inch 8K4K 120Hz LCD with LTPS TFT
- Author
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Ya-Ling Hsu, Hsiao-Wei Cheng, Che-Min Lin, Chu-Kuan Yu, and Chun-Ru Huang
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Materials science ,Liquid-crystal display ,Thin-film transistor ,business.industry ,law ,Optoelectronics ,business ,law.invention - Published
- 2021
3. Conformal Epitaxy Zno/Gaox Superlattices: From Theory to Experiment
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Lin Che-Min, Che-Min Lin, P.C. Kung, Tsan-Chuen Leung, and Q. Yung-Sung Chen
- Published
- 2022
4. Site-Specific Response Spectra Developed by Considering Near-Fault Motions in Taiwan
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Jyun-Yan Huang, Shu-Hsien Chao, Che-Min Lin, Shang-Yi Hsu, Chung-Che Chou, Chiun-Lin Wu, and Chin-Hsiung Loh
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
5. Shallow Subsurface Structure in the Hualien Basin and Relevance to the Damage Pattern and Fault Rupture during the 2018 Hualien Earthquake
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Takumi Hayashida, Chun Hsiang Kuo, Yasuhiro Matsumoto, Yin Tung Yen, Che Min Lin, Keng Chang Kuo, Masumi Yamada, Yujia Guo, Jim Mori, Ken Miyakoshi, and Ikuo Cho
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geography ,Geophysics ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Geochemistry and Petrology ,Relevance (information retrieval) ,Fault (geology) ,Structural basin ,010502 geochemistry & geophysics ,01 natural sciences ,Seismology ,Geology ,0105 earth and related environmental sciences - Abstract
The 2018 Mw 6.4 Hualien earthquake generated a large peak-to-peak velocity of over 2 m/s, with a period of 3 s at the south end of the Milun fault, which resulted in the collapse of five buildings. To investigate the shallow subsurface soil structure and evaluate possible effects on the ground motion and building damage, we performed microtremor measurements in the Hualien basin. Based on the velocity structure jointly inverted from both Rayleigh-wave dispersion curves and microtremor horizontal-to-vertical spectral ratio data, we found that the shallow subsurface structure generally deepens from west to east. Close to the Milun fault, the structure becomes shallower, which is consistent with faulting during the 2018 earthquake and the long-term tectonic displacement. There is no significant variation for the site conditions in the north–south direction that can explain the large peak ground velocity in the south. As a result of the dense measurements in the heavily damaged area, where three high-rise buildings totally collapsed, these locations have the average S-wave velocity of the upper 30 m (AVS30) values and are relatively high compared to the more distant area from the Meilun River. This is somewhat unusual, because lower AVS30 values indicating softer ground conditions are expected close to the river. We did not find any characteristic subsurface soil structure that may contribute to the building collapses. The large 3 s pulse was probably generated by source effects, rather than subsurface soil amplification.
- Published
- 2020
6. Implementing horizontal-to-vertical Fourier spectral ratios and spatial correlation in a ground-motion prediction equation to predict site effects
- Author
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Jyun Yan Huang, Shu Hsien Chao, Kuo-Liang Wen, Che Min Lin, Chun Hsiang Kuo, and Yi-Hau Chen
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Physics ,Ground motion ,Spatial correlation ,010504 meteorology & atmospheric sciences ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Computational physics ,Strong ground motion ,symbols.namesake ,Geophysics ,Fourier transform ,symbols ,0105 earth and related environmental sciences - Abstract
We propose a methodology to implement horizontal-to-vertical Fourier spectral ratios (HVRs) evaluated from strong ground motion induced by earthquake (EHVRs) or ambient ground motion observed from microtremor (MHVRs) individually and simultaneously with the spatial correlation (SC) in a ground-motion prediction equation (GMPE) to improve the prediction accuracy of site effects. We illustrated the methodology by developing an EHVRs-SC-based model which supplements Vs30 and Z1.0 with the SC and EHVRs collected at strong motion stations, and a MHVRs-SC-based model that supplements Vs30 and Z1.0 with the SC and MHVRs observed from microtremors at sites which were collocated with strong motion stations. The standard deviation of the station-specific residuals can be reduced by up to 90% when the proposed models are used to predict site effects. In the proposed models, the spatial distribution of the predicted station terms for peak ground acceleration (PGA) from MHVRs at 3699 sites is consistent with that of the predicted station terms for PGA from EHVRs at 721 strong motion stations. Prediction accuracy for stations with inferred Vs30 is similar to that of stations with measured Vs30 with the proposed models. This study provides a methodology to simultaneously implement SC and EHVRs, or SC and MHVRs in a GMPE to improve the prediction accuracy of site effects for a target site with available EHVRs or MHVRs information.
- Published
- 2020
7. Preparation of graphene-embedded hydroxypropyl cellulose/chitosan/polyethylene oxide nanofiber membranes as wound dressings with enhanced antibacterial properties
- Author
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Hsyue-Jen Hsieh, Yung-Chi Chang, Da-Ming Wang, Shin C. Chang, Che-Min Lin, Tzu-Yang Hsien, Li-Chang Cheng, and Chao-Hsien Liu
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Absorption of water ,Polymers and Plastics ,Chemistry ,Hydroxypropyl cellulose ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Chitosan ,chemistry.chemical_compound ,Membrane ,Chemical engineering ,Specific surface area ,Nanofiber ,Ultimate tensile strength ,Glutaraldehyde ,0210 nano-technology - Abstract
Electrospun nanofiber membranes possess high specific surface area with small pores and thus can be developed as wound dressings for absorbing exudate and also preventing bacterial penetration. In this study, hydroxypropyl cellulose (H), chitosan (C) and polyethylene oxide (P) were chosen as membrane materials to increase the hydrophilicity, anti-bacterial property, and yield of nanofibers, respectively. Additionally, graphene (G) was added to enhance the anti-bacterial property of the membranes. As indicated by SEM, the HCP and HCPG solutions (containing H:4.5 wt%, C:4.5 wt%, P:0.75 wt%, without/with G:0.5 wt%) could be electrospun into HCP and HCPG nanofiber membranes with good fiber morphology using a non-toxic solvent system. Further, the membranes were crosslinked by glutaraldehyde vapor to improve the strength. The tensile strength of the membranes was 1.38–1.82 MPa with a swelling ratio up to 1330–1410%. The water vapor transmission rate (WVTR) of wet HCPG membrane was about 3100 g/m2-day, close to the recommended WVTR of wound dressings. The anti-bacterial properties of the membranes were confirmed using three tests against Escherichia coli (Gram-negative bacterium) and Staphylococcus aureus (Gram-positive bacterium). Highly hydrophilic HCP and HCPG membranes prevented the bacterial adherence. The presence of the membranes (especially graphene-embedded HCPG membrane) also greatly reduced bacterial growth. The small pore sizes of HCP and HCPG nanofiber membranes prevented the bacterial penetration to cause infection. Taken together, the HCP and HCPG nanofiber membranes possessed good mechanical properties, appropriate WVTR and high water absorption thus suitable for absorbing wound exudate. Besides, the membranes exhibited nontoxic, anti-fibroblast adhesion and anti-bacterial properties. Therefore, HCP and HCPG nanofiber membranes have the potential to become superior anti-bacterial wound dressings.
- Published
- 2020
8. Ethnic disparity in prevalence and associated risk factors of myopia in adolescents
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Che-Min Lin, Tzu-Heng Weng, Shih-Min Lin, and Shang-Yi Chiang
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Male ,Adolescent ,National Health and Nutrition Examination Survey ,Population ,Ethnic group ,Lower risk ,White People ,Odds ,Risk Factors ,Mexican Americans ,Myopia ,Prevalence ,Humans ,Medicine ,Risk factor ,education ,lcsh:R5-920 ,education.field_of_study ,business.industry ,Hispanic or Latino ,General Medicine ,Odds ratio ,Nutrition Surveys ,United States ,Confidence interval ,Black or African American ,Logistic Models ,Socioeconomic Factors ,Multivariate Analysis ,Female ,lcsh:Medicine (General) ,business ,Demography - Abstract
Background/Purpose: To examine ethnic disparity in prevalence and associated factors of myopia in adolescents using the Unites States National Health and Nutrition Examination Survey (NHANES) dataset. Methods: Participants who were aged 12–19 years were included from NHANES (1999–2008). Logistic regression analyses were applied to identify risk factors associated with myopia after stratification by race. Results: A total of 9,960 participants were included in the prevalence analysis, and 6,571 in the risk factor analysis. Other race (excluded Mexican American, other Hispanic, non-Hispanic white, non-Hispanic black) participants had the highest frequency of myopia (42.77%). Multivariate analyses of the whole population suggested that the odds of myopia were significantly lower in participants with household smokers (odds ratio [OR] = 0.79, 95% confidence interval [CI]: 0.66–0.97), and significantly greater in Mexican American race (OR = 1.28, 95% CI: 1.01–1.62), other Hispanic (OR = 1.79, 95% CI: 1.10–2.92) and in participants with senior high school graduate education (OR = 1.79, 95% CI: 1.01–3.18), watched 2 hours of television daily (OR = 1.27, 95% CI: 1.02–1.59), used the computer for 1 hour daily (OR = 1.276, 95% CI: 1.02–1.57). When examined by race/ethnicity, 1 hour of computer use increased the odds of myopia in the non-Hispanic White group, in Mexican Americans a higher family poverty income ratio and 2 hours of television time was associated with myopia, and in the Other Hispanic group, a higher family poverty income ratio was associated with myopia, while males and those with a higher sugar had a lower risk of myopia. Conclusion: Risk factors for myopia vary with race/ethnicity. Keywords: Adolescent, Myopia, Racial disparity, Risk factor, NHANES
- Published
- 2020
9. Peak ground acceleration estimation using P-wave parameters and horizontal-to-vertical spectral ratios
- Author
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Rih-Teng Wu, Ting-Yu Hsu, Chia Wei Liang, Chun Hsiang Kuo, and Che Min Lin
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lcsh:Geology ,Physics ,Atmospheric Science ,Peak ground acceleration ,Computer Science::Neural and Evolutionary Computation ,lcsh:QE1-996.5 ,P wave ,Earth and Planetary Sciences (miscellaneous) ,lcsh:G1-922 ,Oceanography ,lcsh:Geography (General) ,Computational physics - Abstract
Peak ground acceleration (PGA) can be used to estimate the seismic intensity. However, using P-wave features to estimate PGA is a challenging task. One of the reasons for that is that a seismic wave commonly undergoes modification due to various site effects, consequently leading to uncertainty in the predicted PGA. In order to accommodate site effects using site parameters together with P-wave parameters, this paper takes advantage of machine learning to consider multiple parameters simultaneously. Several artificial neural network (ANN) models considering different site effect parameters are constructed. The performances of these ANN models were investigated and compared. In total, 53531 ground motion data obtained from the Taiwan Strong Motion Instrumentation Program were utilized to develop the proposed approach. It was found that the proposed ANN model with horizontal-to-vertical spectral ratio parameters effectively reduces the error of the estimated PGA when compared with either the ANN model without site parameters or the ANN model with other site parameters.
- Published
- 2020
10. Design and Implementation of a Door Latch Unlocking Mechanism
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Che-Min Lin, Yu-Hsun Chen, and Kuan-Lun Hsu
- Published
- 2021
11. The High-Frequency Decay Parameter (Kappa) in Taiwan
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Chun Te Chen, Che Min Lin, Ming Wey Huang, Shun Chiang Chang, Jyun Yan Huang, Chun Hsiang Kuo, and Kuo-Liang Wen
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Physics ,Instrumentation ,Elevation ,010502 geochemistry & geophysics ,Geodesy ,01 natural sciences ,Spectral line ,Shear (sheet metal) ,symbols.namesake ,Geophysics ,Amplitude ,Fourier transform ,Geochemistry and Petrology ,symbols ,Seismogram ,Kappa ,0105 earth and related environmental sciences - Abstract
The high-frequency decay parameter kappa (κ) was computed by fitting Fourier amplitude spectra from the seismic network of the Taiwan Strong Motion Instrumentation Program (TSMIP). The κ of shear horizontal waves (SH waves) was calculated for individual recordings, and the relationship between κ values and the epicentral distance (Repi) of each station was derived for each station. The κ value at Repi = 0 (denoted as κ0) can be used as a site parameter. There are totally 26,277 seismograms that have been recorded at 679 TSMIP stations over the period of 1993 through 2014 with local magnitudes of 4.0–7.1 and focal depths less than 30 km. The estimation of κ0 for Taiwan ranges from 0.0208 to 0.147 s, and the spatial distribution of κ0 was closely related to geology and velocity. The site-specific κ0 values from 425 stations were correlated with the averaged shear wave velocity of the top 30 m of strata (VS30), and the relationship could be described as κ0 = (0.125 ± 0.005) − (0.011 ± 0.001) × ln(VS30), and an acceptable linear correlation (R2 = 0.57) was performed. The results may be used in the future application of ground motion prediction equations (GPMEs) and serve as simulation parameters. Also, the relationship between κ0 and the depth to engineering rock (Z1.0) is not well correlated, whereas an acceptable correlation exists between κ0 and other site proxies (i.e., elevation and resonant frequency).
- Published
- 2019
12. Standby Power Management of a Smart Home Appliance by Using Energy Saving System With Active Loading Feature Identification
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Che-Min Lin and Ming-Tang Chen
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business.industry ,Computer science ,020206 networking & telecommunications ,02 engineering and technology ,Energy consumption ,Reliability engineering ,Energy conservation ,Electric energy ,Identification (information) ,Home automation ,0202 electrical engineering, electronic engineering, information engineering ,Media Technology ,Electrical and Electronic Engineering ,business ,Standby power ,Energy (signal processing) - Abstract
Recently, energy conservation has been concerned, and there are several aspects to improve the energy consumption issues. Therefore, many research results were proposed to mitigate the related problems, one of these is to eliminate the extra standby power of household appliances. This paper employed an effective method to identify load characteristics of appliances in different operation states by support vector machines, and a smart home electric energy saving system was built up to implement the method. Furthermore, a virtual living room was simulated in the laboratory as an experimental object, and a prototype system was built up. The performance test results are proposed to validate the feasibility of the proposed system.
- Published
- 2019
13. Co-seismic geomagnetic fluctuations and atmospheric disturbances during the 2018 M 6.2 Hualien Earthquake
- Author
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Horng Yuan Yen, Cheng-Horng Lin, TsungYu Wu, Chun Rong Chen, Strong Wen, Hung Hao Hsieh, Che Min Lin, Chieh-Hung Chen, Bor-Shouh Huang, and Jann-Yenq Liu
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Atmospheric Science ,Infrasound ,lcsh:QE1-996.5 ,lcsh:G1-922 ,Tiltmeter ,Oceanography ,Physics::Geophysics ,lcsh:Geology ,Earth's magnetic field ,Physics::Space Physics ,QuakeFinder ,Earth and Planetary Sciences (miscellaneous) ,lcsh:Geography (General) ,Geology ,Seismology - Abstract
The strong ground motion of 6 February 2018 M 6.2 Hualien Earthquake triggered a series of co-seismic geomagnetic fluctuations and seismo-traveling atmospheric disturbances (STADs) signatures in infrasonic waves and micro-pressures upon the seismic wave arrival. Networks of 9 QuakeFinder systems, 3 infrasound systems, 2 tiltmeters, 2 micro-barometers, and 11 co-located seismometers are used in this study. Each QuakeFinder system consists of a 3-axes induction magnetometer, an air conductivity sensor, a geophone, and temperature/relative humidity sensors. Co-seismic signatures clearly appear in the induction magnetometers, infrasound systems, and micro-barometers data. The magnetometers register both high- and lowfrequency pulsations. Geomagnetic fluctuations occur upon the seismic wave arrival but last a longer duration, while the STADs lag their co-located seismic waves by about 15 - 45 s. The long-lasting fluctuations recorded by both induction and fluxgate magnetometers suggest that the ground/underground water motion play an important role, which is further conformed by low-frequency fluctuations in the tiltmeter data. In general, the amplitude of geomagnetic fluctuations decays as away from the epicenter. However, unusual large co-seismic geomagnetic fluctuations are detected over areas of the abnormal seismic intensity level and/or the magnetic underground structure with anomalously high susceptibilities.
- Published
- 2019
14. Coseismic Velocity Variations Associated with the 2018 Mw 6.4 Hualien Earthquake Estimated Using Repeating Earthquakes
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Ruey Juin Rau, Dawei Mu, Che‐Min Lin, En Jui Lee, and Po Chen
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Geophysics ,010504 meteorology & atmospheric sciences ,010502 geochemistry & geophysics ,01 natural sciences ,Geology ,0105 earth and related environmental sciences - Published
- 2018
15. Incorporation and selective removal of space-forming nanofibers to enhance the permeability of cytocompatible nanofiber membranes for better cell growth
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Che-Min Lin, Da-Ming Wang, Tzu-Yang Hsien, Hsyue-Jen Hsieh, Ting-Yun Kuo, and Shih-Chieh Hung
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food.ingredient ,Chemistry ,Cell growth ,General Chemical Engineering ,technology, industry, and agriculture ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Gelatin ,Electrospinning ,0104 chemical sciences ,Chitosan ,chemistry.chemical_compound ,Membrane ,food ,Chemical engineering ,Permeability (electromagnetism) ,Nanofiber ,sense organs ,Glutaraldehyde ,0210 nano-technology - Abstract
Nanofibrous biomaterials fabricated by electrospinning attract increasing attention. However, electrospun nanofibers are stacked tightly, thus restricting cell infiltration and nutrient supply. To overcome this drawback, we developed three types of cytocompatible nanofiber membranes, namely (1) electrospun chitosan/gelatin/PEO (CGP) composite membrane, (2) co-electrospun CGP/E membrane containing CGP and Eudragit (E) nanofibers, (3) CGP (E removed) membrane which was obtained by selective removal of E nanofibers from CGP/E membrane. The permeability of albumin through CGP, CGP/E, and CGP (E removed) nanofiber membranes increased from 1.50 × 10−11 to 6.19 × 10−11 and further to 15.3 × 10−11 m2/s, respectively. Hence, incorporating large-diameter (space-forming) E nanofibers with CGP nanofibers enhanced the permeability of CGP/E membrane. Moreover, selectively removing E nanofibers from CGP/E membrane further enlarged pore size and created more permeable CGP (E removed) membrane. Membrane strength and stability were reinforced by crosslinking with glutaraldehyde for 2.5 h. To verify our approach, stem cells (KP-hMSCs) were covered by CGP (E removed) or CGP membrane and cultured for 7 days. The cell density underneath CGP (E removed) membrane was about 1.7 times of that underneath CGP membrane, indicating that improved cell growth (proliferation) occurred under CGP (E removed) membrane. Therefore, our approach to create more permeable nanofiber membranes for better cell growth is successful and can be utilized for fabricating various nanofibrous biomaterials.
- Published
- 2018
16. Investigation of shallow S-wave velocity structure and site response parameters in Taiwan by using high-density microtremor measurements
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Chun-Te Chen, Chun-Hsiang Kuo, Che-Min Lin, Jyun-Yan Huang, and Kuo-Liang Wen
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Geology ,Geotechnical Engineering and Engineering Geology - Published
- 2022
17. Identification of Engineering Bedrock in Taiwan based on Site Amplification and Velocity Structures of Strong-motion Stations
- Author
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Che-Min Lin, Jyun-Yan Huang, Chun-Hsiang Kuo, and Kuo-Liang Wen
- Abstract
There are two kinds of bedrocks that are widely used in seismology and earthquake engineering respectively. The seismology field uses the “seismic bedrock” to define an interface that has a practically lateral extent. The strata deeper than this interface is much more homogeneous in comparison with the shallower one. It is common to set the seismic bedrock within the upper crust has 3000 m/sec of the shear wave velocity. In contrast, the earthquake engineering prefers the shallower interface which dominates the main seismic site amplification, especially the predominant frequency of ground motion. The interface is called “Engineering Bedrock”, which the underlying stratum has the shear wave velocity from 300 to 1000 m/sec for different purposes. But, the reference shear wave velocity of the engineering bedrock is mostly defined as 760 m/sec for ground motion prediction and simulation. In Taiwan, the Central Weather Bureau (CWB) constructed and operates a dense strong-motion network called TSMIP (Taiwan Strong Motion Instrument Program), which provides numerous ground motion data for seismology and earthquake engineering. In our previous studies, the shallow shear wave velocity profiles of over 700 TSMIP stations were estimated by the Receiver Function method. The velocity profiles are from the ground surface to the depth with the shear wave velocity of at least 2000 m/sec. It allows us to compare the theoretical site amplification of the velocity profile of TSMIP stations with their observed one from the seismic records. The variance of fitness between theoretical and observed amplifications through shear wave velocity is analyzed to evaluate which reference velocity can appropriately define the depth of engineering bedrock, where the most site amplification occur beneath, in all of Taiwan. The difference between local geology is also discussed. Finally, an engineering bedrock map is proposed for further applications in earthquake engineering.
- Published
- 2020
18. Empirical Site Amplification Modelling for Horizontal and Vertical Ground Motions in Taiwan
- Author
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Chun-Hsiang Kuo, Shu-Hsien Chao, Che-Min Lin, Jyun-Yan Huang, and Kuo-Liang Wen
- Abstract
Site amplification behavior are important in ground motion prediction. Seismic waves were amplified and caused significant building damages in the Taipei Basin by the 1986 Hualien offshore (subduction interface) and the 1999 Chi-Chi earthquakes (crustal), for which both of the epicentral distances were nearly 100 km. To understand local site amplifications in Taiwan, empirical site amplification factors for both horizontal and vertical ground motions are studied using recently constructed strong motion and site databases for the free-field TSMIP stations. Records of large magnitude earthquakes of MW larger than 5.5 from 1991 to 2016 were selected for this study. Site amplification factors at site conditions with Vs30 between 120 m/s to 1600 m/s and bedrock accelerations up to 0.8 g were evaluated using ratios of spectral accelerations at different periods. The reference site condition, i.e. the engineering bedrock, is assumed as Vs30 of 760 m/s (B/C boundary) in this study. Our empirical site amplification form are borrowed from the site response function of ASK14 and CY14 ground motion models in NGA-West2 project with slight modification. Therefore our site amplification model includes a linear amplification term and a nonlinear deamplification term. The coefficients of the empirical models were obtained by a nonlinear regression analysis using the selected Taiwan data. Site amplification factor is a function of Vs30 and spectral intensity in the model. Similar linear site amplification factor to the NGA models is derived in our model; however, more significant soil nonlinearity behavior than the NGA models is likely captured from the empirical data. The amplification factor in vertical component is smaller than that in horizontal.
- Published
- 2020
19. Strong Ground Motion and Pulse‐Like Velocity Observations in the Near‐Fault Region of the 2018 Mw 6.4 Hualien, Taiwan, Earthquake
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Che Min Lin, Jyun Yan Huang, Shu Hsien Chao, Kuo-Liang Wen, Ting-Yu Hsu, and Chun Hsiang Kuo
- Subjects
Strong ground motion ,Geophysics ,010504 meteorology & atmospheric sciences ,010502 geochemistry & geophysics ,01 natural sciences ,Near fault ,Seismology ,Geology ,0105 earth and related environmental sciences ,Pulse (physics) - Published
- 2018
20. Site amplifications and the effect on local magnitude determination at stations of the surface–downhole network in Taiwan
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Nai Chi Hsiao, Che Min Lin, Da Yi Chen, Chun Hsiang Kuo, and Kuo-Liang Wen
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Surface (mathematics) ,Ground motion ,010504 meteorology & atmospheric sciences ,Mode (statistics) ,Soil Science ,Resonance ,Magnitude (mathematics) ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,Geodesy ,01 natural sciences ,Power law ,Intensity (physics) ,Large earthquakes ,Electronic engineering ,Geology ,0105 earth and related environmental sciences ,Civil and Structural Engineering - Abstract
This study analyzed site effects including PGA and empirical transfer functions at 15 selected surface–downhole stations by using ground motion recordings of earthquakes with ML > 4 during 2012 and 2013 in Taiwan. In addition, we used all strong motion recordings of four large earthquakes (ML > 6) to generate intensity distribution maps and assess the differences in magnitude at the surface and downhole. The site amplification factors of the PGA were calculated using the ratio between the surface and downhole recordings. The mean PGA amplification factors ranged from 2 to an exaggerated value of 20 at different stations. In addition, the power law relationships between the PGAs at the surface and downhole were evaluated to understand how amplification varies as PGA increases. Strong ground motions with and without site effects throughout Taiwan could be observed by comparing intensity distribution maps generated using the surface and downhole accelerations from four large earthquakes with magnitudes > 6. Empirical transfer functions derived using the single-station and two-station methods at the same stations showed comparable dominant frequencies and amplification factors; however, the empirical transfer function derived using the two-station method showed clearer resonance peaks, not only at fundamental frequencies but also at higher mode resonance frequencies. The HHSR and the HVSR were highly similar, particularly at medium frequencies. This finding indicates that the HVSR can be used instead of the HHSR when only the surface recording is available. Moreover, the local magnitudes calculated using surface recordings were higher than those calculated using downhole recordings. The differences are attributed to the amplification caused by the sedimentary layers and resultant in 0.36, 0.46 and 0.49 on average for events with ML of > 6, 5–6, and 4–5. Furthermore, HHSRs at 5–10 Hz and 1.1–1.7 Hz were strongly correlated with PGA amplifications and ML differences, respectively.
- Published
- 2018
21. Electrically tunable bandgaps for g-ZnO/ZnX (X = S, Se, Te) 2D semiconductor bilayers
- Author
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Li-Wei Tu, Yu-Hsuan Yu, Chun-Fu Chang, Chi-Chung Kei, Tsan-Chuen Leung, Chien-Wei Chen, Yu-yuan Zheng, Hye-Won Seo, Sung-Wei Yeh, Bor Yann Liaw, Kuan-Tsae Huang, Wanchen Hsieh, P.V. Wadekar, Quark Y. Chen, Kung-Shiuh Huang, Chun-Jung Su, Che-Min Lin, Wei-Kan Chu, Di Chen, Ching-Wen Chang, Yu-Chiao Lin, and Chih-Hsiung Liao
- Subjects
010302 applied physics ,Materials science ,Condensed matter physics ,Condensed Matter::Other ,business.industry ,Orbital hybridisation ,Band gap ,Stacking ,Heterojunction ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Surfaces, Coatings and Films ,Condensed Matter::Materials Science ,Dipole ,Semiconductor ,0103 physical sciences ,Quadrupole ,0210 nano-technology ,Valence electron ,business ,Instrumentation - Abstract
Novel physical properties not seen in their individual layers are obtained from stacked layers of materials. In this report, using the first-principles calculations, we study the electronic band structures of heterostructures composed of graphitic (graphene-like) bilayers of g-ZnO/ZnX (X = S, Se, and Te) semiconductors. The g-ZnO layer is largely planar, but the ZnX layer is somewhat corrugated. Our calculations reveal on the stable formations of a type-II band alignment in bilayers with an AB stacking order of OZnO-ZnZnX and ZnZnO-XZnX. The optical bandgaps are much lowered as compared to the monolayers of ZnO and ZnX constituents, with the conduction band contributed by g-ZnO and valence band by ZnX. There is a quadratic dependence of the bandgap on the external electric biases applied in perpendicular to the interface. This nonlinearity manifests an superposed effect of an interlayer orbital hybridization and associated charge transferring, along with the coexistence of an electric dipole and a quadrupole. There is an overall charge transfer of valence electrons from the ZnX layer to the g-ZnO layer, leading to a pair of highly charge polarized surfaces along with a large built-in potential. The already lowered bandgaps further change with the external bias. This tunability of Eg for g-ZnO/ZnX bilayer heterostructures holds promises for optoelectronic applications covering a wider spectral range of the solar spectrum.
- Published
- 2021
22. Geological implications of the 0212 earthquake in 2014 at the Tatun Volcano Group of Taiwan: Synergistic effects of volcanic and faulting activities
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Che-Min Lin, Min-Hung Shih, Ya-Chuan Lai, Cheng-Horng Lin, Li-Chin Chang, Yi-Heng Li, Hsin-Chieh Pu, and Chih-Wen Kan
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geography ,Focal mechanism ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Seismic zone ,Geology ,Fault (geology) ,010502 geochemistry & geophysics ,01 natural sciences ,Volcano ,Geothermal fluid ,Group (stratigraphy) ,Upper crust ,Aftershock ,Seismology ,0105 earth and related environmental sciences ,Earth-Surface Processes - Abstract
On February 12, 2014, an ML 4.2 earthquake (named 0212 EQ) occurred at the Tatun Volcano Group (TVG) in northern Taiwan. Seismic data from both the regional broadband array in Taiwan and a local dense seismic network in the TVG indicate that the 0212 EQ was located at a depth of 4.3 km near Shamoshan, one of the latest eruptive units in the TVG. Referring to the aftershocks surrounding the 0212 EQ, we further found that (1) they formed a linear seismic zone dipping ∼50° towards the southeast to reach the Shanchiao Fault that cuts through the TVG, (2) focal mechanism of more than half of the larger aftershocks (MD ≥ 1.5) matched this linear seismic zone for a normal faulting, and (3) the seismic b-value was calculated to be 3.55. They are used to delineate the geometry of the Shanchiao Fault at the upper crust and to infer that localized geothermal fluid might have affected the activity of aftershocks as manifested by the very high seismic b-value. The strongly compensated linear vector dipole of the centroid moment tensor suggests the 0212 EQ had a non-double-couple source resulted from the gravitational collapse. Thus, we conclude that the 0212 EQ was a combined synergistic effect of a collapsed reservoir filled with volcanic fluids and faulting activities along the Shanchiao Fault.
- Published
- 2017
23. Characteristics of Optic Disc and Visual Field Changes in Patients with Thyroid-Associated Orbitopathy and Open-Angle Glaucoma
- Author
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Ke-Hung Chien, Chih-Kang Hsu, Yi-Hao Chen, Da-Wen Lu, Hsin-Yu Yao, Hsu-Chieh Chang, and Che-Min Lin
- Subjects
medicine.medical_specialty ,genetic structures ,Open angle glaucoma ,Nerve fiber layer ,open-angle glaucoma ,Glaucoma ,Article ,Optical coherence tomography ,Ophthalmology ,medicine ,hyperthyroidism ,medicine.diagnostic_test ,business.industry ,Blind spot ,Thyroid ,thyroid eye disease ,General Medicine ,medicine.disease ,eye diseases ,Visual field ,medicine.anatomical_structure ,thyroid-associated orbitopathy ,Medicine ,sense organs ,business ,Optic disc - Abstract
This study aimed to characterize the changes in the visual field (VF) patterns and disc morphology of patients with thyroid-associated orbitopathy (TAO) and open-angle glaucoma (OAG). A retrospective review of the medical records at the Tri-Service General Hospital in Taiwan identified 396 eyes of 198 patients with thyroid-associated glaucoma. A final follow-up of VF examination in 140 eyes revealed 114 eyes with VF defects, indicating disease progression. The characteristics of and changes in disc morphology, optical coherence tomography findings, and VF defects were statistically analyzed. The most common VF defects at the initial diagnosis and the end of the follow-up period were inferior partial arcuate (17%) and paracentral (15%) defects, respectively. The most common VF defect in patients with unspecific disc signs was an unspecific scotoma (13%). The most common optic disc feature was disc cupping (51%), followed by parapapillary atrophy (48%). The most frequent location of nerve fiber layer thinning was the inferotemporal region (48%). VF defects showed a significantly more pronounced progression in the non-nerve fiber bundle group than in the nerve fiber bundle group (p <, 0.001). This study details the characteristics and progression of disc morphology and VF defects in patients with TAO and OAG.
- Published
- 2021
24. Near-surface frequency-dependent nonlinear damping ratio observation of ground motions using SMART1
- Author
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Che Min Lin, Chun Te Chen, Chun Hsiang Kuo, Jyun Yan Huang, and Kuo-Liang Wen
- Subjects
Physics ,Damping ratio ,0211 other engineering and technologies ,Phase (waves) ,Soil Science ,Spectral density ,Magnitude (mathematics) ,020101 civil engineering ,02 engineering and technology ,Geotechnical Engineering and Engineering Geology ,0201 civil engineering ,Computational physics ,Nonlinear system ,Range (statistics) ,Shear stress ,Scaling ,021101 geological & geomatics engineering ,Civil and Structural Engineering - Abstract
The damping ratio is an important index used in soil nonlinearity studies and is mostly proportional to the shear strain increase. Previous researches indicated a frequency-independent damping in most cases. In this study, frequency-dependent damping was introduced from frequency-dependent Q calculated through the spectral ratio method of near-surface structures using the power spectrum of strong motion records in the Strong Motion Array in Taiwan Phase I (SMART1). The dense SMART1 recorded significant strong motions in the 1980s, which can be used to identify soil nonlinearity at near surfaces. A 40%–50% increase in frequency-dependent damping for SMART1 was identified, with strain increasing from 0.01% to 0.1% in near-surface regions. A large damping was also found in the shallow sediments with mean Vs below 600 m/s on the topmost 500 m layers in the SMART1 database at a frequency range of 3–8 Hz, which is independent of the magnitude scaling or near-field travel distance scaling relations.
- Published
- 2021
25. Questionnaire surveys on damages at high-rise buildings and synthesized near-fault long-period strong ground motions of the 2018 Hualien, Taiwan, earthquake
- Author
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Che Min Lin, Wen Yen Chang, Xin Wang, Masayuki Nagano, Chun Hsiang Kuo, and Hongjun Si
- Subjects
021110 strategic, defence & security studies ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,0211 other engineering and technologies ,Geology ,02 engineering and technology ,Building and Construction ,Fault (geology) ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Near fault ,Long period ,Damages ,Microtremor ,Motion generation ,Safety Research ,Source model ,Seismology ,0105 earth and related environmental sciences ,High rise - Abstract
Long-period pulse-like strong ground motions were recorded near the Milun fault and caused serious building damages in the Hualien City during the main shock of the 2018 Hualien, Taiwan, earthquake. In this paper, questionnaire survey on feeling of shaking, indoor damages, structural, and nonstructural damages to high-rise reinforced concrete residential buildings were analyzed by three building groups according to the positions to the Milun fault and different site conditions. Relationships between the results of questionnaire survey on building damages and characteristics of strong ground motions were studied. Furthermore, a characterized seismic source model was proposed to elucidate the generation mechanism of near-fault long-period strong ground motions. In this model, a shallow strong motion generation area (SMGA7) in the south part of Milun fault with rise-time of 2.6 s contributed to the long-period pulse-like strong ground motions. Besides, a deep SMGA (SMGA8) under the SMGA7 with rise-time of 1.2 s also contributed to the strong ground motions. Using this model, strong ground motions at the sites of buildings for questionnaire survey were synthesized. Because of the directivity effects, amplitudes of ground motions were increased from north to south along the Milun fault, which can explain the serious building damages at the buildings located at the southwest to the Milun fault. The reasons of building damages were also examined from the aspect of predominant periods of ground sites and fundamental periods of buildings, which were extracted from microtremor measurement. Damages at the buildings located on the central part of the hanging wall with relatively good site condition were the lightest for almost all the surveyed items. Pulses with period in the range of 1 s–2 s which were generated by the SMGA8 and amplified by the near surface layers are considered to be responsible for building damages.
- Published
- 2021
26. Site correction of a high-frequency strong-ground-motion simulation based on an empirical transfer function
- Author
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Che-Min Lin, Chun-Te Chen, Chun Hsiang Kuo, Jyun-Yan Huang, Kuo-Liang Wen, and Shuen-Chiang Chang
- Subjects
geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Geology ,Function (mathematics) ,Fault (geology) ,010502 geochemistry & geophysics ,01 natural sciences ,Transfer function ,Physics::Geophysics ,Strong ground motion ,symbols.namesake ,Fourier transform ,Amplitude ,Frequency domain ,Stochastic simulation ,symbols ,Seismology ,0105 earth and related environmental sciences ,Earth-Surface Processes - Abstract
In this study, an empirical transfer function (ETF), which is the spectrum difference in Fourier amplitude spectra between observed strong ground motion and synthetic motion obtained by a stochastic point-source simulation technique, is constructed for the Taipei Basin, Taiwan. The basis stochastic point-source simulations can be treated as reference rock site conditions in order to consider site effects. The parameters of the stochastic point-source approach related to source and path effects are collected from previous well-verified studies. A database of shallow, small-magnitude earthquakes is selected to construct the ETFs so that the point-source approach for synthetic motions might be more widely applicable. The high-frequency synthetic motion obtained from the ETF procedure is site-corrected in the strong site-response area of the Taipei Basin. The site-response characteristics of the ETF show similar responses as in previous studies, which indicates that the base synthetic model is suitable for the reference rock conditions in the Taipei Basin. The dominant frequency contour corresponds to the shape of the bottom of the geological basement (the top of the Tertiary period), which is the Sungshan formation. Two clear high-amplification areas are identified in the deepest region of the Sungshan formation, as shown by an amplification contour of 0.5 Hz. Meanwhile, a high-amplification area was shifted to the basin’s edge, as shown by an amplification contour of 2.0 Hz. Three target earthquakes with different kinds of source conditions, including shallow small-magnitude events, shallow and relatively large-magnitude events, and deep small-magnitude events relative to the ETF database, are tested to verify site correction. The results indicate that ETF-based site correction is effective for shallow earthquakes, even those with higher magnitudes, but is not suitable for deep earthquakes. Finally, one of the most significant shallow large-magnitude earthquakes (the 1999 Chi-Chi earthquake in Taiwan) is verified in this study. A finite fault stochastic simulation technique is applied, owing to the complexity of the fault rupture process for the Chi-Chi earthquake, and the ETF-based site-correction function is multiplied to obtain a precise simulation of high-frequency (up to 10 Hz) strong motions. The high-frequency prediction has good agreement in both time and frequency domain in this study, and the prediction level is the same as that predicted by the site-corrected ground motion prediction equation.
- Published
- 2017
27. Luminescence enhancement of SrZn2(PO4)2:Eu2+,Mn2+ phosphor co-doped with Al3+
- Author
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Wei-Jun Wang, Su-Hua Yang, Tu-Chieh Hung, Che-Min Lin, and Wei-Min Tung
- Subjects
010302 applied physics ,Ligand field theory ,Materials science ,Photoluminescence ,Mechanical Engineering ,Doping ,Metals and Alloys ,Analytical chemistry ,Phosphor ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Redox ,Bond length ,Crystallinity ,Mechanics of Materials ,0103 physical sciences ,Materials Chemistry ,0210 nano-technology ,Luminescence - Abstract
This study demonstrates the emission enhancement of Al 3+ co-doped SrZn 2 (PO 4 ) 2 :Eu 2+ ,Mn 2+ phosphors. The crystallinity and emission mechanism were investigated, and the results indicate that co-doping with Al 3+ increased the atomic concentrations of Sr and P and induced the formation of Al–O bonds. The formation of P–O–P bonds was also facilitated. Furthermore, the crystal field strength of Mn 2+ –O 2- was decreased, and the reduction reaction of Eu 3+ to Eu 2+ was promoted. Photoluminescence measurements revealed a 2.83-fold enhancement of the Eu 2+ emission upon co-doping with 0.46 mol of Al 3+ . However, the Mn 2+ emission decreased and was blue-shifted because of the increased bond length of Mn 2+ –O 2- and decreased ligand field around Mn 2+ . The phosphor decay time was also reduced with increasing Al 3+ concentration.
- Published
- 2017
28. XPS analysis and luminescence mechanism of white SrZn2(PO4)2:Eu2+,Mn2+ phosphor with In3+ sensitizer
- Author
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Che-Min Lin, Su-Hua Yang, Tu-Chieh Hung, Min-Wen Wang, and Wei-Min Tung
- Subjects
010302 applied physics ,Chemistry ,Mechanical Engineering ,Doping ,Binding energy ,Metals and Alloys ,Analytical chemistry ,Phosphor ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ion ,X-ray photoelectron spectroscopy ,Mechanics of Materials ,Yield (chemistry) ,Excited state ,0103 physical sciences ,Materials Chemistry ,0210 nano-technology ,Luminescence - Abstract
The influence of In 3+ doping on the binding energy of ions and the energy transfer mechanism of white SrZn 2 (PO 4 ) 2 :Eu 2+ ,Mn 2+ phosphor was investigated. The ligand fields around Sr 2+ and Mn 2+ varied with different kinds of doped ions, while those around Zn 2+ and Eu 2+ remained stable. Doping with In 3+ created traps of charged species and clustered pairs in the phosphor. These traps captured excited carriers, leading to a decrease in energy transfer from Eu 2+ to Mn 2+ and a decline in Mn 2+ emission. However, carriers stored temporarily in traps then migrated to Eu 2+ to yield an enhanced Eu 2+ emission. The phosphor emission was blue-shifted by the increase in In 3+ concentration. Maximum Eu 2+ energy absorption and emission were obtained when doped with 12 mol% of In 3+ . The decay time of the phosphor was 11.74 ms.
- Published
- 2016
29. S-wave velocity structure and site effect parameters derived from microtremor arrays in the Western Plain of Taiwan
- Author
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Chun Te Chen, Shun Chiang Chang, Jyun Yan Huang, Kuo-Liang Wen, Chun Hsiang Kuo, and Che Min Lin
- Subjects
Ground motion ,geography ,HVSR ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Bedrock ,Taiwan ,Geology ,Structural basin ,010502 geochemistry & geophysics ,01 natural sciences ,Microtremor array ,symbols.namesake ,S-wave ,symbols ,Z1.0 ,Rayleigh wave ,Microtremor ,Bay ,Seismology ,0105 earth and related environmental sciences ,Earth-Surface Processes - Abstract
In this study, microtremor array measurements were conducted at 45 sites in the Western Plain of Taiwan. The arrays were approximately 30 m or 60 m in radius, depending on the site. The maximum-likelihood frequency–wavenumber method was adopted to obtain the phase velocities of Rayleigh waves, and then a genetic algorithm technique based on an inversion scheme of the fundamental mode of the Rayleigh waves’ dispersion curves was applied to calculate a preliminary S-wave velocity (Vs) profile at each site. Because a layer of thick sediment covers the bedrock in the Western Plain of Taiwan, microtremor arrays in this size range cannot estimate the structure of the entire sediment. Therefore, this study implemented further inversion of the horizontal-to-vertical spectral ratios of the microtremors to estimate the deeper structures up to the bedrock of Vs greater than 1000 m/s. Previously logged velocity profiles for different depths at or near our study sites were collected and compared with the Vs profiles derived from our microtremor array measurements; the results were found to be highly comparable. Therefore, we could delineate the depth distributions for the layer depths for Vs = 600 m/s and 1000 m/s in this region. The depth for Vs = 600 m/s is approximately 50 m in the piedmont area and approximately 300 m at the coastline; moreover, the depths for Vs = 1000 m/s increase from 200 m in the piedmont area to approximately 1000 m at the coastline. The depths for Vs = 1.0 km/s (Z1.0), which is an important parameter that accounts for the basin effect in recent ground motion prediction equations, are consequently available at the study sites. The distribution of Z1.0 as a function of Vs30 indicates higher similarity to that in Japan than in the San Francisco Bay area.
- Published
- 2016
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30. Masseter Muscle Volume Changes Evaluated by 3-Dimensional Computed Tomography After Repeated Botulinum Toxin A Injections in Patients With Square Facial Morphology
- Author
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Philip Kuo Ting Chen, Jyh-Ping Chen, Che Min Lin, Christopher Glenn Wallace, Chun Shin Chang, Susie Lin, Lun-Jou Lo, Zung Chung Chen, Yen Chang Hsiao, Yu Ray Chen, and Gavin Chun-Wui Kang
- Subjects
Adult ,Esthetics ,3 dimensional computed tomography ,030230 surgery ,Injections, Intralesional ,Injections, Intramuscular ,Sampling Studies ,Statistics, Nonparametric ,Botulinum toxin a ,Masseter muscle ,03 medical and health sciences ,0302 clinical medicine ,Imaging, Three-Dimensional ,Medicine ,Neurotoxin ,Humans ,In patient ,Botulinum Toxins, Type A ,Contouring ,business.industry ,Masseter Muscle ,Hypertrophy ,Organ Size ,Middle Aged ,Treatment Outcome ,030220 oncology & carcinogenesis ,Surgery ,Female ,Tomography ,business ,Nuclear medicine ,Tomography, X-Ray Computed ,Volume (compression) - Abstract
Botulinum neurotoxin A (BoNT-A) is a minimally invasive and technically straightforward treatment of masseter muscle (MM) volume reduction and facial contouring, but the literature on its long-term effect on MM volume remains unclear.This study aimed to assess quantitatively for progressive volume changes of lower facial contour after 3 BoNT-A injections in patients with bilateral MM hypertrophy causing square facial morphology using 3-dimensional computed tomographic scans.Ten female patients with square facial morphology due to bilateral MM hypertrophy were recruited to, and 6 completed, this clinical study. Each received 24 U of BoNT-A into the inferior portion of each MM on both sides, repeated 6 monthly to complete 3 treatments. Masseter muscle volume changes were assessed using 3-dimensional computed tomography at pretreatment (before injections) and posttreatment (1 year after the third injection).Mean MM volume significantly reduced from 26.39 ± 4.18 cm before treatment to 23.26 ± 4.31 cm 1 year after treatment (P = 0.002).Three consecutive 6-monthly BoNT-A injections into the MMs reduced their volume by 12% when assessed 1 year after completion of treatment.
- Published
- 2018
31. Performance of the NCREE's on-site warning system during the 5 February 2016Mw6.53 Meinong earthquake
- Author
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Ting-Yu Hsu, Kuo-Liang Wen, Che Min Lin, Chun Hsiang Kuo, Hsui Hsien Wang, and Pei Yang Lin
- Subjects
Peak ground acceleration ,Earthquake engineering ,010504 meteorology & atmospheric sciences ,Warning system ,Southern taiwan ,Earthquake warning system ,Moment magnitude scale ,010502 geochemistry & geophysics ,01 natural sciences ,Geophysics ,Epicenter ,General Earth and Planetary Sciences ,Seismology ,Geology ,0105 earth and related environmental sciences - Abstract
The National Center for Research on Earthquake Engineering in Taiwan has developed an on-site earthquake early warning system (NEEWS). The Meinong earthquake with a moment magnitude of 6.53 and a focal depth of 14.6 km occurred on 5 February 2016 in southern Taiwan. It caused 117 deaths, injured 551, caused the collapse of six buildings, and serious damage to 247 buildings. During the Meinong earthquake, the system performance of 16 NEEWS stations was recorded. Based on a preassigned peak ground acceleration (PGA) threshold to issue alarms at different stations, no false alarms or missed alarms were issued during the earthquake. About 4 s to 33 s of lead time were provided by the NEEWS depending on the epicenter distance. In addition, the directivity of the earthquake source characteristic and also possibly the site effects were observed in the diagram of the distribution of PGA difference between the predicted PGA and the measured PGA.
- Published
- 2016
32. Performance of a Low‐Cost Earthquake Early Warning System (P‐Alert) during the 2016ML 6.4 Meinong (Taiwan) Earthquake
- Author
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Wen-Tzong Liang, Himanshu Mittal, Wei-An Chao, Bor-Shouh Huang, Che Min Lin, Yih-Min Wu, and Cheng-Horng Lin
- Subjects
Geophysics ,010504 meteorology & atmospheric sciences ,Warning system ,Environmental science ,Earthquake warning system ,Central weather bureau ,010502 geochemistry & geophysics ,01 natural sciences ,Alert system ,Seismology ,0105 earth and related environmental sciences - Abstract
On 5 February 2016, a moderate earthquake occurred in southwestern Taiwan with M L 6.4 and a focal depth of 16.7 km. This earthquake caused damage to a few buildings and 117 casualties. A low‐cost earthquake early warning (EEW) system ( P ‐alert) is in operation for the purpose of EEW and for providing near‐real‐time shake maps. During this event, a detailed shaking map was generated by the P ‐alert system within 2 min after the earthquake occurrence, and the high shaking regions strongly correlated with the locations in which the damage and casualties occurred. In the field, individual P ‐alert devices also serve as onsite EEW systems using P ‐wave information. The individual P ‐alert provided a 4–8 s lead time before the arrival of violent shaking in the damaged regions. For regional EEW, both the Central Weather Bureau (CWB, official agency) and the P ‐alert system responded very well. Currently, regional warnings in Taiwan are only provided to cities at epicentral distances of 50 km or more by the CWB. For cities within a 50‐km epicentral distance, the P ‐alert system could be useful for providing onsite EEW. The performance of the P ‐alert network during this earthquake proves the efficiency of this real‐time, low‐cost network in terms of early warning (regional and onsite), near‐real‐time shake maps, rapid reports, and strong‐motion data for research purposes.
- Published
- 2016
33. Intrinsic ferromagnetism and anomalous Hall effect in GaN thin film by Mn delta doping
- Author
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Li-Wei Tu, Che-Min Lin, Yuan-Ting Lin, Tsan-Chuen Leung, Cheng-Maw Cheng, P.V. Wadekar, Quark Y. Chen, and Ching-Wen Chang
- Subjects
Materials science ,Gallium nitride ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,Transition metal ,Hall effect ,Condensed Matter::Superconductivity ,Materials Chemistry ,Spintronics ,Condensed matter physics ,Mechanical Engineering ,Doping ,Metals and Alloys ,Heterojunction ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Ferromagnetism ,chemistry ,Mechanics of Materials ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology ,Molecular beam epitaxy - Abstract
Compound semiconductors doped with magnetically active transition metals (TM) are actively pursued for semiconductor spintronics. Herein we report that delta doping (δ-doping) has been used to incorporate manganese (Mn) into the gallium nitride (GaN) matrix resulting in phase pure highly crystalline heteroepitaxial thin films of (Ga,Mn)N on c-plane sapphire (Al2O3) by plasma-assisted molecular beam epitaxy. Magnetotransport measurements reveal the anomalous Hall effect (AHE) while magnetic measurements show the existence of ferromagnetic ordering. Density functional theory calculations show that δ-doping of Mn atom enables exchange interactions between the Mn 3d states and N 2p states thereby resulting in spin polarized holes in the valence band giving rise to observed AHE and ferromagnetism. This work opens new avenues for incorporating spin polarized carriers in III-nitrides based semiconductors by creating magnetically active Mn layers in heterostructures for spintronics applications.
- Published
- 2020
34. Comparing the Performance of the NEEWS Earthquake Early Warning System Against the CWB System During the 6 February 2018Mw 6.2 Hualien Earthquake
- Author
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Che Min Lin, Y. W. Chang, Pei Yang Lin, Ting-Yu Hsu, Kuo-Liang Wen, H. W. Chiang, Chun Hsiang Kuo, and H. H. Wang
- Subjects
Geophysics ,010504 meteorology & atmospheric sciences ,General Earth and Planetary Sciences ,Earthquake warning system ,010502 geochemistry & geophysics ,01 natural sciences ,Geology ,Seismology ,0105 earth and related environmental sciences - Published
- 2018
35. Energy transfer mechanism and luminescence properties of color tunable LaPO4:Tm,Eu phosphor
- Author
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Che-Min Lin, Po-Jui Chiang, Su-Hua Yang, and Chia-Hung Yen
- Subjects
Ligand field theory ,Photoluminescence ,Materials science ,Process Chemistry and Technology ,Doping ,Analytical chemistry ,Phosphor ,Photochemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ion ,Atomic electron transition ,Materials Chemistry ,Ceramics and Composites ,Luminescence ,Excitation - Abstract
The energy transfer mechanism between Tm 3+ and Eu 3+ ions in the phosphate phosphor was investigated. The addition of Eu facilitated the incorporation of O atoms into the LaPO 4 :Tm,Eu phosphor lattice, which induced changes in its ligand field and energy absorption. Excitation energy was transferred from Tm 3+ to Eu 3+ ions by the mechanism of dipole–dipole interaction. The increase in Eu concentration increased the probability of energy transfer between Tm 3+ and Eu 3+ as well as the electron transition probabilities in Eu 3+ ; a color-tunable emission was observed through variation in the Eu concentration. The highest energy transfer efficiency of Tm 3+ –Eu 3+ was approximately 93%. The critical distance, for energy transfer, between Tm 3+ and Eu 3+ , was 14.5 A. The luminescence of the phosphor declined with a double-exponential mechanism. The decay time decreased as the Eu doping concentration was increased.
- Published
- 2015
36. Simulation of the records of the 27 March 2013 Nantou Taiwan earthquake using modified semi-empirical approach
- Author
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Che Min Lin, Sandeep, Piu Dhibar, Mukat Lal Sharma, Chun Hsiang Kuo, Kuo-Liang Wen, and Anand Y. Joshi
- Subjects
Atmospheric Science ,geography ,Peak ground acceleration ,geography.geographical_feature_category ,Mean squared error ,Bedrock ,Rake ,Shake ,Strong ground motion ,Acceleration ,Earth and Planetary Sciences (miscellaneous) ,Range (statistics) ,Geology ,Seismology ,Water Science and Technology - Abstract
It is seen that strong motion generation area plays an important role in the shaping of strong motion records at the observation point. Strong motion generation areas identified within the rupture plane of the 27 March 2013 Nantou, Taiwan, earthquake (Mw = 5.9) have been modelled in this work. It is seen that all available records are at the surface which include site amplification terms. The modified semi-empirical technique effectively simulates records at rock site. The site amplification terms in all records have been removed using SHAKE 91 program and velocity input at each site. The observed records corrected for site amplification terms are further used for comparison with simulated record at the bedrock from several models. Once the observed records at soil sites are transferred at the bedrock, the next task is selection of final model that gives best fit records. Peak ground acceleration from simulated record at four sites is compared with that from corrected observed data. Since the semi-empirical technique of simulation is strongly dependent on various modelling parameters such as dip, strike, rake, rupture velocity and starting points of rupture, these parameters change iteratively in a specified range in a heuristic way to obtain best modelling parameters. The model giving minimum root mean square error (RMSE) is retained at final model. It is seen that minimum root mean square error of the wave form comparison has been obtained at four stations for the source model having single strong motion generation area. Strong motion records have been simulated at four different recording stations. Comparison of observed and simulated records has been made in terms of RMSE between simulated and observed acceleration records, velocity records and the response spectra at each of four stations. Comparison of waveforms and parameters extracted from observed and simulated records confirms the efficacy of the modified technique to model earthquake characterized by SMGAs.
- Published
- 2015
37. Luminescence of CNT coated LaPO4:Tm phosphors and their field emission lamp application
- Author
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Che-Min Lin, Chih-Ka Yang, Jia-Hung Yan, and Su-Hua Yang
- Subjects
Photoluminescence ,Materials science ,Mechanical Engineering ,Binding energy ,Metals and Alloys ,Analytical chemistry ,Nanotechnology ,Phosphor ,Cathodoluminescence ,Carbon nanotube ,engineering.material ,law.invention ,Field electron emission ,Coating ,Mechanics of Materials ,law ,Materials Chemistry ,engineering ,Luminescence - Abstract
When the phosphor LaPO4:Tm was coated with carbon nanotubes (CNTs), carbon atoms were diffused into the phosphor lattice. Binding energy of La 3d and C 1s were not shifted by CNT coating, while that of O 1s was lowered slightly as a result of the formation of C O and C O bonds on the phosphor surface. CNT coating increased the atomic concentrations of O and C by 27.4% and 9%, respectively. Photoluminescence intensity decreased significantly, by 52%, when CNT concentration of 1.5 wt% was coated. This is attributed to covering the phosphor with black CNTs/carbons and the formation of C O and C O bonds on the phosphor surface. Conversely, cathodoluminescence (CL) intensity was improved by a factor of 3.86 when 1.25 wt% of CNTs was coated, attributing to improved conductivity, reduced charging, and increased CL excitation probability of the phosphor. The influence of CNT coating on the luminescence of LaPO4:Tm was compared with that of LaPO4:Eu phosphor. Blue CL was observed from LaPO4:Tm, it is potential for field emission lamp application.
- Published
- 2014
38. A first near real-time seismology-based landquake monitoring system
- Author
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Jui-Ming Chang, Yih-Min Wu, Yue-Gau Chen, Li Zhao, Che-Min Lin, Hongey Chen, and Wei-An Chao
- Subjects
Identification (information) ,Multidisciplinary ,010504 meteorology & atmospheric sciences ,Computer science ,Typhoon ,Real-time computing ,Hazard mitigation ,Process (computing) ,Monitoring system ,010502 geochemistry & geophysics ,01 natural sciences ,Article ,0105 earth and related environmental sciences - Abstract
Hazards from gravity-driven instabilities on hillslope (termed ‘landquake’ in this study) are an important problem facing us today. Rapid detection of landquake events is crucial for hazard mitigation and emergency response. Based on the real-time broadband data in Taiwan, we have developed a near real-time landquake monitoring system, which is a fully automatic process based on waveform inversion that yields source information (e.g., location and mechanism) and identifies the landquake source by examining waveform fitness for different types of source mechanisms. This system has been successfully tested offline using seismic records during the passage of the 2009 Typhoon Morakot in Taiwan and has been in online operation during the typhoon season in 2015. In practice, certain levels of station coverage (station gap 106 m3 and area > 0.20 km2) are required to ensure good performance (fitness > 0.6 for successful source identification) of the system, which can be readily implemented in other places in the world with real-time seismic networks and high landquake activities.
- Published
- 2017
39. Improvement of the Luminescence of Red LaPO4:Eu Nanophosphors for a Near-UV LED
- Author
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Chih-Ka Yang, Jia-Hung Yan, Che-Min Lin, and Su-Hua Yang
- Subjects
Materials science ,Photoluminescence ,Coprecipitation ,Analytical chemistry ,Phosphor ,Condensed Matter Physics ,Phosphate ,Electronic, Optical and Magnetic Materials ,Crystallinity ,chemistry.chemical_compound ,Pulmonary surfactant ,chemistry ,Materials Chemistry ,Electrical and Electronic Engineering ,Sodium dodecyl sulfate ,Luminescence - Abstract
The luminescence of LaPO4:Eu phosphors was improved by coprecipitation with phosphate from different sources and with anionic surfactants. The effects of the method of synthesis on the characteristics of the phosphors were investigated. When H3PO4 was used as the source of phosphate, strong absorption of the charge transfer band (CTB) was observed. A red shift of the CTB absorption was observed when (NH4)2HPO4 and Na5P3O10 were used as sources of phosphate. Phosphors with high crystallographic symmetry of Eu3+ in the lattice were synthesized when (NH4)2HPO4 was used. The optimum crystallinity and the maximum photoluminescence (PL) intensity were obtained when the phosphor surface was modified with 1 mol.% (NaPO3)6 and 3 mol.% sodium dodecyl sulfate (SDS) surfactant, with PL intensity being increased by 10% and 7%, respectively.
- Published
- 2014
40. Chitosan/pectin/gum Arabic polyelectrolyte complex: Process-dependent appearance, microstructure analysis and its application
- Author
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Ruei-Yi Tsai, Che-Min Lin, Ting-Yun Kuo, Tzu-Yang Hsien, Pin-Wen Chen, Da-Ming Wang, and Hsyue-Jen Hsieh
- Subjects
food.ingredient ,Polymers and Plastics ,Pectin ,Chitosan ,Gum Arabic ,Acetic acid ,chemistry.chemical_compound ,food ,Drug Stability ,Polymer chemistry ,Materials Chemistry ,Insulin ,Drug Carriers ,Viscosity ,Organic Chemistry ,Membranes, Artificial ,Microstructure ,Polyelectrolyte ,Membrane ,chemistry ,Chemical engineering ,Delayed-Action Preparations ,Pectins ,Gum arabic ,Drug carrier ,Hydrophobic and Hydrophilic Interactions - Abstract
Novel chitosan/pectin/gum Arabic polyelectrolyte complex (PEC) solutions and membranes with various compositions were prepared for biomedical applications. The appearance of the PEC solutions, either clear or turbid, was process-dependent and depended on how the three components were dissolved and mixed. The addition of gum Arabic to the chitosan and pectin significantly decreased the viscosities of the resultant PEC solutions due to the formation of globe-like microstructures that was accompanied by network-like microstructures and other molecular entanglements. The mechanical strength and hydrophilicity of the PEC membranes manufactured from the PEC solutions, especially for a weight ratio of 84/8/8 (chitosan/pectin/gum Arabic), were enhanced compared to pure chitosan membranes. Moreover, the use of the 84/8/8 PEC membranes as a drug carrier exhibited steady and fairly complete release of a drug (insulin) for 6h. Based on these promising results, the chitosan/pectin/gum Arabic PEC membranes have great potential in controlled drug release applications.
- Published
- 2014
41. Rapid on-site peak ground acceleration estimation based on support vector regression and P-wave features in Taiwan
- Author
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Che Min Lin, Tao Ming Chang, Shieh-Kung Huang, Yu Weng Chang, Ting-Yu Hsu, Chun Hsiang Kuo, Kuo-Liang Wen, and Chin-Hsiung Loh
- Subjects
Support vector machine ,Peak ground acceleration ,Amplitude ,Soil Science ,P-wave ,Regression analysis ,Particle displacement ,Spectral acceleration ,Geotechnical Engineering and Engineering Geology ,Geology ,Seismology ,Standard deviation ,Civil and Structural Engineering - Abstract
This study extracted some P-wave features from the first few seconds of vertical ground acceleration of a single station. These features include the predominant period, peak acceleration amplitude, peak velocity amplitude, peak displacement amplitude, cumulative absolute velocity and integral of the squared velocity. The support vector regression was employed to establish a regression model which can predict the peak ground acceleration according to these features. Some representative earthquake records of the Taiwan Strong Motion Instrumentation Program from 1992 to 2006 were used to train and validate the support vector regression model. Then the constructed model was tested using the whole earthquake records of the same period as well as the 2010 Kaohsiung earthquake with 6.4 M L . The effects on the performance of the regression models using different P-wave features and different length of time window to extract these features are studied. The results illustrated that, if the first 3 s of the vertical ground acceleration was used, the standard deviation of the predicted peak ground acceleration error of the whole tested 15-years earthquake records is 20.89 gal.The length of time window could be shortened, e.g. 1 s, and the prediction error is slightly sacrificed, in order to prolong the lead-time before destructive S-waves reaches.
- Published
- 2013
42. Development of a smart home energy saving system combining multiple smart devices
- Author
-
Ming-Tang Chen and Che-Min Lin
- Subjects
Engineering ,Smart system ,business.industry ,Smart meter ,Control unit ,020206 networking & telecommunications ,SDS Protocol ,02 engineering and technology ,Power (physics) ,Home automation ,Power consumption ,Embedded system ,0202 electrical engineering, electronic engineering, information engineering ,business ,Energy (signal processing) - Abstract
In this paper, a smart home electric energy saving system is built up by combining smart devices (smart meter and smart plug), communication modules, and smart mobile phones. The functions of the smart meter include display and storage of total power consumption, electric energy parameters, and abnormal operation conditions, etc. Besides, user can check power consumption information remotely, and the electric energy saving of appliance is implemented by smart plug under the control of smart phone. The smart plug consists of different communication modules, load control unit, and LCD display. Home members can use smart phone to check the power consuming information via internetwork, and the control of electric appliance can be implemented by the App on the smart phone through the WiFi interfaces. Moreover, the power information at the smart plug can be transmitted to the smart meter by ZigBee modules. Finally, to confirm the performance of the smart home electric energy saving system, a prototype was built up and tested at lab, and the test results validate the feasibility of the proposed system.
- Published
- 2016
43. Site classification and Vs30 estimation of free-field TSMIP stations using the logging data of EGDT
- Author
-
Kai Wen Kuo, Kuo-Liang Wen, Tao Ming Chang, Che Min Lin, Hung Hao Hsieh, and Chun Hsiang Kuo
- Subjects
Estimation ,Engineering ,Earthquake engineering ,business.industry ,Instrumentation ,Logging ,Borehole ,Extrapolation ,Geology ,Geotechnical Engineering and Engineering Geology ,Geodesy ,Free field ,Set (abstract data type) ,Geotechnical engineering ,business - Abstract
The Engineering Geological Database for TSMIP (EGDT), the Taiwan Strong Motion Instrumentation Program, has been under construction by the National Center for Research on Earthquake Engineering and the Central Weather Bureau in Taiwan since 2000. Site characterization, comprising surface investigations and logging measurements, was carried out throughout the project. We provide a set of specifications and a description to help users understand the subject matter of the database. EGDT contains 469 surveyed stations, 439 of which were drilled and the logging measurements completed. Of these, 385 had logging data reaching at least 30 m, and we used these to examine and determine the most accurate extrapolation of Vs30 (the average S-wave velocity of the top 30 m of strata) for the other 54 stations with velocity profiles less than 30 m. The chosen method assumed that the bottom velocity is identical from the actual depth of the hole to a distance of 30 m, that is, the Bottom Constant Velocity (BCV) method. In order to utilize other existing boreholes which have only N values but no velocities in the future, the empirical S-wave velocity equations for seven different regions and the whole of Taiwan were evaluated by a multivariable analysis. Henceforth, for those existing boreholes which have an N profile less than 30 m, the S-wave velocity profile can first be calculated by empirical S-wave velocity equations, and then Vs30 can be estimated by reliable extrapolation. Some other studies of site classifications of TSMIP stations were compared with our results to demonstrate the necessity of reclassification. Ultimately, the Vs30 values of the 439 drilled free-field TSMIP stations were derived and the new site classification was achieved according to the Vs30-based provisions of the National Earthquake Hazards Reduction Program.
- Published
- 2012
44. Evaluating empirical regression equations for Vs and estimating Vs30 in northeastern Taiwan
- Author
-
Chun Te Chen, Hung Hao Hsieh, Kuo-Liang Wen, Chun Hsiang Kuo, Che Min Lin, and Tao Ming Chang
- Subjects
Ground motion ,Multivariable calculus ,Wave velocity ,Extrapolation ,Soil Science ,Soil science ,Geotechnical Engineering and Engineering Geology ,Geology ,Seismology ,Seismic wave ,Regression ,Civil and Structural Engineering - Abstract
The shear wave velocity of shallow sediments is very important in seismic wave amplification and thus Vs 30 is a well-known parameter for site classification. Based on the relationship between Vs and soil indexes, the empirical regression equations were evaluated using more than 600 data sets from the Ilan area and the Taipei Basin. Multivariable analysis, which can increase the accuracy of regression equations, was used in this study. Three extrapolations were compared, and then the most accurate bottom-constant extrapolation was adopted to estimate Vs 30 at 16 boreholes, none of which reached a depth of 30 m. Ultimately Vs 30 was derived for 110 free-field strong motion stations, and the stations in northeastern Taiwan were reclassified according to the Vs 30-based NEHRP provisions. Regression equations of Vs and the extrapolation of Vs 30 were also applied to boreholes with only N -values and corresponding depths of less than 30 m for assessing the Vs 30 and NEHRP class.
- Published
- 2011
45. A Self-Sensing Microgripper Module With Wide Handling Ranges
- Author
-
Che-Min Lin, Chao-Chieh Lan, and Chen-Hsien Fan
- Subjects
Engineering ,business.industry ,technology, industry, and agriculture ,Mechanical engineering ,Stiffness ,Shape-memory alloy ,Structural engineering ,SMA ,Computer Science Applications ,body regions ,Control and Systems Engineering ,Grippers ,medicine ,Mechanical advantage ,Electronics ,Electrical and Electronic Engineering ,medicine.symptom ,business ,Robotic arm ,Contraction (operator theory) - Abstract
A compliant two-fingered microgripper is designed, fabricated, and demonstrated. To mimic human finger actuation, the proposed finger is distributively actuated by a shape memory alloy (SMA) wire. An SMA-actuated finger model is presented to predict SMA strain and finger motion given its contraction force. Based on this model, the finger shape and SMA wire dimension are optimally designed. The gripper is shown to have a wide handling range, high mechanical advantage, and sufficient out-of-plane stiffness; thus, it can accommodate objects of various sizes and weights. To control its motion, the SMA contraction force is estimated by using the proposed force to electrical resistance model. Gained from the simple driving electronics and self-sensing of SMA, the fabricated gripper can be made compact and lightweight. Finally, a self-powered gripper module is attached to a robot arm to perform several illustrative manipulations.
- Published
- 2011
46. Machine Learning-Based Configuration Parameter Tuning on Hadoop System
- Author
-
Chao-Chun Yeh, Ye-Qi Zhuo, Shih-Wei Liao, Che-Min Lin, and Chi-Ou Chen
- Subjects
Optimization problem ,Computer science ,business.industry ,Process (computing) ,Machine learning ,computer.software_genre ,Software framework ,Task (computing) ,Job performance ,Programming paradigm ,Key (cryptography) ,Artificial intelligence ,Focus (optics) ,business ,computer - Abstract
Apache Hadoop system is a software framework with the capability to process large-scale datasets across a cluster of distributed machines using MapReduce programming model. However, there are two main challenges for system administrators to manage the Hadoop system, (1) system administrators are difficult to tune the parameters appropriately since the behaviors and characteristics of large-scale distributed systems are too complicated, (2) there are dozens of configuration parameters affecting the system performance which makes the configuration parameters tuning task becomes troublesome. In this paper, we focus on optimizing the Hadoop MapReduce job performance by tuning configuration parameters, and then we propose an analytical method to help system administrators choose approximately optimal configuration parameters depending on the characteristics of each application. Our approach has two key phases: prediction and optimization phase. The prediction phase is to estimate the performance of a MapReduce job, whereas the optimization phase is to search the approximately optimal configuration parameters strategically by invoking the predictor repeatedly. In our evaluation results, our work can help system administrators to improve the performance about 2X to 8X better than traditional methods.
- Published
- 2015
47. Design and implementation of a smart home energy saving system by multi-microprocessors
- Author
-
Ming-Tang Chen and Che-Min Lin
- Subjects
Power-line communication ,Engineering ,Smart grid ,Electricity meter ,Smart meter ,business.industry ,Energy management ,Embedded system ,Electric energy consumption ,Electric power ,Standby power ,business - Abstract
This paper proposes a home electric energy saving network which consists of a smart meter and a smart plug. The smart meter can not only measure electric power parameters of a load also identify the operation status of a device which is connected to the smart plug. Therefore, the standby power consumption of the device can be reduced to the minimum through the electric energy management algorithm. Besides, real time electric energy consumption and standby power information will be delivered to the assigned user through the communication network of the smart meter; so, the reliability and the effectiveness of home electric energy management can be improved. For the hardware structure, the system includes digital signal processors (DSPs), a power energy IC, a smart plug and a communication module. Regarding software development, the system has the following functions: energy recording, standby power consumption management, electric billing, and power information collection. The system prototype is installed at a personal residence, and the performance is validated by the test results.
- Published
- 2015
48. A case report of Löfgren's syndrome (a variant of sarcoidosis) with atypical manifestations in a Taiwan Chinese man
- Author
-
Chia-Hung Li, Ming-Ling Tsai, Chi-Ting Horng, Da-Wen Lu, Che-Min Lin, and Chun-Ling Hung
- Subjects
medicine.medical_specialty ,S syndrome ,Conjunctiva ,Löfgren's syndrome ,Atypical manifestations ,medicine.diagnostic_test ,Systemic steroid ,business.industry ,medicine.disease ,Dermatology ,Dysphagia ,eye diseases ,Surgery ,Ophthalmology ,acute body weight loss ,medicine.anatomical_structure ,Hilar lymph nodes ,ocular redness ,Biopsy ,medicine ,sarcoidosis ,sense organs ,Sarcoidosis ,medicine.symptom ,business - Abstract
A 28-year-old Chinese man presented with refractory ocular redness in the bilateral eyes. His symptoms co-existed with dysphasia and acute body weight loss. Excisional biopsy of the conjunctiva and hilar lymph nodes was performed and Lofgren's syndrome was confirmed. The patient was treated with systemic steroid and symptoms gradually subsided over the 2-year follow-up period. Ocular redness and dysphagia with acute body weight loss are atypical symptoms of Lofgren's syndrome. Careful survey and prompt treatment is necessary.
- Published
- 2012
49. Luminescence properties of Tm3+ and Eu3+ co-doped LaPO4 phosphor for white-light emission
- Author
-
Jia-Hung Yan, Che-Min Lin, and Su-Hua Yang
- Subjects
Wavelength ,Materials science ,Doping ,White light ,Phosphor ,Luminescence ,Photochemistry ,Luminance ,Co doped ,Intensity (heat transfer) - Abstract
For the synthesis of white-light phosphor, red Eu3+ with different concentrations was co-doped into the blue LaPO 4 :Tm phosphor. It was found that the luminance at wavelength of 454 nm decreased gradually; on the contrary, reddish-orange emission at wavelength 594 nm was strengthened when the Eu3+ concentration was increased. The maximum red luminescent intensity was obtained when 7 mol% of Eu3+ was doped. Obviously, energy transfer between Tm3+ and Eu3+ occurred. Consequently, white-light emission was observed.
- Published
- 2014
50. Use of gum arabic to improve the fabrication of chitosan-gelatin-based nanofibers for tissue engineering
- Author
-
Tzu-Yang Hsien, Hsyue-Jen Hsieh, Ruei-Yi Tsai, Che-Min Lin, Da-Ming Wang, Shih-Chieh Hung, and Ting-Yun Kuo
- Subjects
food.ingredient ,Materials science ,Polymers and Plastics ,Nanofibers ,Gelatin ,Polyvinyl alcohol ,Chitosan ,chemistry.chemical_compound ,Gum Arabic ,food ,Tensile Strength ,Materials Chemistry ,Cell Adhesion ,Humans ,Composite material ,Cells, Cultured ,Acetic Acid ,Cell Proliferation ,Aqueous solution ,Tissue Engineering ,Viscosity ,Organic Chemistry ,Mesenchymal Stem Cells ,Electrospinning ,Cross-Linking Reagents ,chemistry ,Glutaral ,Nanofiber ,Polyvinyl Alcohol ,Gum arabic ,Glutaraldehyde ,Porosity - Abstract
Current techniques for fabricating chitosan-gelatin-based nanofibers require the use of corrosive and expensive solvents. Our novel method, however, using gum arabic and a mild (20 wt%) aqueous acetic acid solution as solvent can produce a solution with much higher chitosan-gelatin content (16 wt%). Without gum arabic, which greatly decreases the viscosity of the solution, such an outcome was unachievable. The solution was utilized to prepare electrospun chitosan-gelatin-polyvinyl alcohol-gum arabic nanofibers with a weight ratio of 8:8:2:0.5 (C8G8P2A0.5 nanofibers), in which polyvinyl alcohol could stabilize the electrospinning process. The stability and tensile strength (2.53 MPa) of C8G8P2A0.5 nanofibers (mats) were enhanced by glutaraldehyde crosslinking. Furthermore, mesenchymal stem cells attached and proliferated well on the mat. The strength-enhanced and cytocompatible C8G8P2A0.5 mats are thereby suitable for tissue engineering applications. More importantly, we have created a less expensive and safer method (one not using hazardous solvents) to fabricate chitosan-gelatin-based nanofibers.
- Published
- 2014
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