A5025923467- Advanced MRI Techniques and Applications
- Photonic and Optical Devices
- GaN-based semiconductor devices and materials
- Semiconductor Lasers and Optical Devices
- Advanced Fiber Optic Sensors
- Advanced optical system design
- Nuclear Physics and Applications
- Semiconductor Quantum Structures and Devices
- MRI in cancer diagnosis
- Organic Light-Emitting Diodes Research
- Atomic and Subatomic Physics Research
- Lanthanide and Transition Metal Complexes
- Semiconductor materials and devices
- Optical Coatings and Gratings
- Luminescence Properties of Advanced Materials
- Quantum and electron transport phenomena
- Advanced Neuroimaging Techniques and Applications
- Medical Imaging Techniques and Applications
- Nuclear physics research studies
- Laser Material Processing Techniques
- Advanced Measurement and Metrology Techniques
- Photonic Crystal and Fiber Optics
- Electrowetting and Microfluidic Technologies
- Surface Roughness and Optical Measurements
- Thin-Film Transistor Technologies
Siemens (China)
2024
GenMont Biotech (Taiwan)
2024
National Taiwan Normal University
2024
National Tsing Hua University
2024
National Taiwan University
1963-2022
University Medical Center Freiburg
2019
University of Freiburg
2019
National Pingtung University of Science and Technology
2008-2018
Aalto University
2013-2014
Cheng Shiu University
2013
A glass phosphor layer with ultra-high thermal stability appropriate for phosphor-converted white light-emitting diodes (PC-WLEDs) is demonstrated. The results showed PC-WLEDs utilizing the high stable maintained good in lumen, chromaticity, and transmittance characteristics under aging condition up to 350°C. This a considerable operating temperature PC-WLEDs. lumen degradation, chromaticity shift, loss glass-based at 150°C , 250°C 350°C 450°C are also presented compared those of...
High-power light-emitting diode (LED) modules encapsulated with different lens shapes after a thermal-aging test were studied experimentally and numerically. Samples from manufacturers aged at 80degC, 100degC, 120degC under constant driving voltage of 3.2 V. The results showed that the LED hemispherical-shaped plastic exhibited better lifetime due to thermal dissipation than those cylindrical-or elliptical-shaped lenses. Results also optical power increased removing because degradation...
We report on the first fabrication of a Cr-doped fiber using drawing-tower method with Cr:YAG as core preform. Both Cr3+ and Cr4+ ions coexist in fiber, amplified spontaneous emission (ASE) spectrum shows broadband 1.2 to 1.55 mum which can not be realized by currently available amplifiers. This indicates that new fibers have potential for being used amplifier cover bandwidth entire 1.3-1.6 range exhibit 300 nm usable spectral bands.
We observed flat, smooth heterointerfaces in GaAs/AlAs superlattices grown on GaAs (311)A by molecular-beam epitaxy. In our investigation of superlattice structures along both the [011\ifmmode\bar\else\textasciimacron\fi{}] and [2\ifmmode\bar\else\textasciimacron\fi{}33] directions cross-section transmission-electron microscopy, we found that formed orientation are sharp smooth. This indicates surface is stable for epitaxial growth. Thus, it clear recently reported occurrence interface...
InSb epitaxial films were grown on GaAs and Si substrates by molecular-beam epitaxy using an intermediate AlSb buffer layer. The use of layer greatly facilitates the overgrowth significantly lattice-mismatched foreign substrates, such as Si. Hall mobility, x-ray rocking curve, infrared absorption measurements performed to characterize samples. Using a 300 nm layer, 3 μm thick with room-temperature electron mobilities high 55 000 cm2 V−1 s−1 routinely achieved. X-ray curve linewidths 199...
Purpose The purpose of this study is to introduce a novel design method shim coil array specifically optimized for whole brain shimming and compare the performance resulting coils conventional spherical harmonic shimming. Methods proposed approach based on stream function singular value decomposition. Eighty‐four field maps from 12 volunteers measured in seven different head positions were used during process. cross validation technique was applied find an optimal number elements array....
Multivalent ligands hold promise for enhancing avidity and selectivity to simultaneously target multimeric proteins, as well potentially modulating receptor signaling in pharmaceutical applications. Essential these manipulations are nanosized scaffolds that precisely control ligand display patterns, which can be achieved by using polyproline oligo-helix macrocyclic nanoscaffolds
The fiber alignment shifts induced by the postweld shift (PWS) in laser-welded transistor outline (TO)-Can-type laser module packages were studied experimentally and numerically. PWS-induced quantitatively determined four geometrical parameters, namely: 1) lateral (r); 2) position angle (/spl alpha/); 3) swing theta/); 4) tilt psi/). measured coupling powers before welding, after a welding compensation clearly confirmed with dominant parameters of r /spl alpha/ that due to PWS could be...
The postweld-shift (PWS) compensation techniques employing a laser displacement meter (LDM) in the transistor outline (TO)-Can-type laser-welded module package and high-magnification camera with image capturing system (HMCICS) butterfly-type packages are quantitatively investigated compared. results show that fiber alignment shifts due to PWS can be aligned back closer their original optimum position after applying proposed techniques, hence coupling powers loss could regained significantly....
This paper reports the enhanced performance of dye-sensitized solar cells (DSSCs) with photoanodes fabricated using polystyrene (PS) balls embedded in pastes. During photoanode sintering processes, PS evaporated, leaving randomly distributed cavities photoanodes. These multiple scattering light, thus increasing optical path to improve absorption light by N719 dyes. The short circuit current and efficiency were both improved 17% (to 5.51%) for DSSCs, whose made diameter
High thermal stability of high-power phosphor-converted white-light-emitting diodes (PC-WLEDs) incorporating a Ce:YAG-doped glass as the phosphor layer is demonstrated. An exploring study lumen loss, chromaticity shift, and transmittance loss PC-WLEDs with silicone under aging at 150°C for 500 hours was performed compared. The results showed that 6 wt% exhibited 60% less 50% lower (CIE) 20% smaller than silicone. This clearly indicates exhibits higher after aging. A better may be beneficial...
We have observed beating Shubnikov–de Haas oscillations in Al0.18Ga0.82N/GaN [112¯0]-direction quantum wires grown on (0001) sapphire. The spin-splitting energy, (2.4±0.3) meV for 200 nm wire, was suppressed to (1.2±0.3) 100 wire and smeared by the scattering from edge states intersubbands. spin splitting of Rashba effect can be used control differential phase shift spin-polarized electrons when a gate bias is applied nanometer arm ring. Based results AlxGa1−xN/GaN nanowire, one-dimensional...
Spin-splitting energies of wurtzite AlN and InN are calculated using the linear combination atomic orbital method, data analyzed utilizing two-band k⋅p model. It is found that in scheme, a spin-degenerate surface exists Brillouin zone. Consequently, D’yakonov-Perel’ spin relaxation mechanism can be effectively suppressed for all components [001]-grown quantum wells (QWs) at resonant condition through application appropriate strain or suitable gate bias. Therefore, QWs (e.g., InGaN/AlGaN...
A new scheme of oriented-hyperboloid microlens (OHM) with passive alignment to achieve high polarized extinction ratio (PER) is proposed and demonstrated efficiency coupling high-power 980 nm pump lasers polarization maintaining fibers (PMFs). Using an automatic grinding machine a charge-coupled-device precisely control attain the required minor radius curvature 4-4.8 μm, offset within 0.7 axis orientation accuracy ±1°, OHM exhibited high-average PER 31.7 dB, 83.4%. For 30 dB PER, angular...
For ultra-low-field MRI, the spatial-encoding magnetic fields generated by gradient coils can have strong concomitant leading to prominent image distortion. Additionally, using superconducting magnet pre-polarize magnetization improve signal-to-noise ratio of MRI. Yet spatially inhomogeneous remanence field due permanently trapped flux inside a pre-polarizing coil modulates and causes further distortion.We propose two-stage frequency-space (f-x) formulation accurately describe dynamics...
Purpose High‐field magnetic resonance imaging (MRI) has the challenge of inhomogeneous B 1 + , and consequently flip angle distribution, which causes spatially dependent contrast makes clinical diagnosis difficult. Method We propose a two‐step pulse design procedure in (1) combination linear nonlinear spatial encoding fields (SEMs) is used to remap map order reduce dimensionality problem, (2) locations, amplitudes, phases spoke pulses are estimated one dimension. The advantage this remapping...
The authors have experimentally investigated photoexcitation effects on carrier transports through a Ge quantum-dot (QD)∕SiO2 system via resonant tunneling diode (RTD). Features of oscillation and negative differential conductance are observed from the current Ge-QDs RTDs at room temperature. not only displays additional oscillatory peaks but also exhibits enhanced peak-to-valley ratio under photoexcitation. This indicates that holes created in QD by lead to channels electron-hole...
A quantitative postweld shift (PWS) correction employing a notch-saddle-compensation technique (NSCT) in laser-welded butterfly-type laser module package is presented. predetermined notch geometry proposed to guide the welding compensation specific direction and magnitude precisely. The results show that 82% 99% of relative coupling efficiency before for modules achieved by using NSCT. fiber shifts due PWS can be realigned back closer their original optimum position after applying NSCT,...
An oriented-dependence-microlens (ODM) visual alignment and packaging for lasers coupling to polarization-maintaining-fibers (PMFs) is proposed demonstrated. The ODM fabricated by automatic grinding accurate positioning techniques. position accuracy of the machine ±1°, which less than aligned angular tolerance ±2° necessary achieve both high 80% polarized extinction ratio 30 dB. This indicates that endface fast axis can be visually observed then surface feature laser polarization direction....