150 results on '"Liang-An Chen"'
Search Results
2. Non-integral model-based scatterometry for CD metrology of single high-aspect-ratio microstructures
- Author
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Wei-Hsin Chein, Fu-Sheng Yang, Zi-Ying Fu, and Liang-Chia Chen
- Subjects
Process Chemistry and Technology ,Materials Chemistry ,Instrumentation ,Surfaces, Coatings and Films - Abstract
This article presents an innovative model-based scatterometry method for CD metrology of single high-aspect-ratio (HAR) microstructures, which are increasingly utilized in advanced packaging, especially as vertical interconnects in three-dimensional integrated circuits. The rapidly growing aspect ratio of these HAR structures makes it challenging to monitor their critical dimensions (CD). Furthermore, conventional spectral reflectometry or scatterometry measurements on periodic metrology targets on the scribe lines of the wafer are inadequate in providing a reliable correlation with the in-die structures due to the integral nature of these measurements, which can result in additional measurement errors compared to measuring individual in-die structures. To address these challenges, we propose a novel scatterometry system that can achieve high-precision single-structure measurement of fine-pitch HAR structures with significantly improved light efficiency over conventional optical methods. Our system takes advantage of the high spatial coherence of the supercontinuum laser source and an optical NA-controlled design concept for precise light beam shaping, enabling high spatial resolution and superior light efficiency in measurements. Furthermore, we demonstrate a model-based measurement scheme that uses a virtual optical system for complete characterization of the sample profile. The experimental results show that the proposed system can accurately measure RDL structures with fine nominal spacing as small as 1 μm and an aspect ratio of 3:1 with high fidelity.
- Published
- 2023
3. The effect of the Doppler mismatch in microwave electrometry using Rydberg electromagnetically induced transparency and Autler–Townes splitting
- Author
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Zhou, Fei, primary, Jia, Feng-Dong, additional, Mei, Jiong, additional, Liu, Xiu-Bin, additional, Zhang, Huai-Yu, additional, Yu, Yong-Hong, additional, Liang, Wei-Chen, additional, Qin, Jian-Wei, additional, Zhang, Jian, additional, Xie, Feng, additional, and Zhong, Zhi-Ping, additional
- Published
- 2022
- Full Text
- View/download PDF
4. Lysozyme-assisted ultrasonic exfoliation of graphitic carbon nitride into highly stable nanosheets with enhanced bactericidal capacity
- Author
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Liang-Liang Chen, Wen-Pu Shi, Tuo-Di Zhang, Ren-Bin Zhou, Xiao-Qian Jin, Ya-Qing Zhou, Wen-Juan Lin, Wei-Hong Guo, and Da-Chuan Yin
- Subjects
Mechanics of Materials ,Mechanical Engineering ,General Materials Science ,General Chemistry ,Condensed Matter Physics - Abstract
Graphitic carbon nitride (g-C3N4) is a visible light-responsive photocatalytic material with important application prospects in many fields. However, the interaction between g-C3N4 monolayers makes it easy to aggregate and precipitate in aqueous solutions, and it is necessary to prepare stable g-C3N4 aqueous dispersions for their applications. Here we propose a facile, green, and low-cost method for the preparation of stable g-C3N4 dispersions by ultrasonicating g-C3N4 in lysozyme (LYZ) solution. The LYZ was adsorbed on the surface of g-C3N4 through non-covalent interactions such as electrostatic interaction, hydrogen bonding and π-cation interaction to prevent the aggregation of g-C3N4 nanolayers. The LYZ/g-C3N4 could quickly re-form a uniform aqueous dispersion solution after freeze-drying, and exhibit good stability. Further, the results of photocatalytic sterilization showed that the assisted dispersion of LYZ enhanced the bactericidal activity of g-C3N4 and exhibited promising application prospects in the field of biomedicine and water disinfection.
- Published
- 2022
5. Synergistic influences of titanium, boron, and oxygen on large-size single-crystal diamond growth at high pressure and high temperature
- Author
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Guang-Tong Zhou, Yu-Hu Mu, Yuan-Wen Song, Zhuang-Fei Zhang, Yue-Wen Zhang, Wei-Xia Shen, Qian-Qian Wang, Biao Wan, Chao Fang, Liang-Chao Chen, Ya-Dong Li, and Xiao-Peng Jia
- Subjects
General Physics and Astronomy - Abstract
The synergistic influences of boron, oxygen, and titanium on growing large single-crystal diamonds are studied using different concentrations of B2O3 in a solvent–carbon system under 5.5 GPa–5.7 GPa and 1300 °C–1500 °C. It is found that the boron atoms are difficult to enter into the crystal when boron and oxygen impurities are doped using B2O3 without the addition of Ti atoms. However, high boron content is achieved in the doped diamonds that were synthesized with the addition of Ti. Additionally, boron–oxygen complexes are found on the surface of the crystal, and oxygen-related impurities appear in the crystal interior when Ti atoms are added into the FeNi–C system. The results show that the introduction of Ti atoms into the synthesis cavity can effectively control the number of boron atoms and the number of oxygen atoms in the crystal. This has important scientific significance not only for understanding the synergistic influence of boron, oxygen, and titanium atoms on the growth of diamond in the earth, but also for preparing the high-concentration boron or oxygen containing semiconductor diamond technologies.
- Published
- 2022
6. GRB 190530A: From Precursor, Prompt Emission to Afterglow all Originated from Synchrotron Radiation
- Author
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Hui-Ya Liu, Xiang-Gao Wang, Li-Ping Xin, Zi-Min Zhou, Liang-Jun Chen, Bing Li, Yuan-Gui Yang, Qi Luo, Cheng-Kui Li, Shao-Lin Xiong, Ling-Jun Wang, Xu-Hui Han, Li-Ming Song, Jian-Yan Wei, En-Wei Liang, and Shuang-Nan Zhang
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Space and Planetary Science ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
GRB 190 530A was jointly observed by the High Energy X-ray Telescope of the Hard X-ray Modulation Telescope (Insight-HXMT/HE) and the Ground-Based Wide-Angle Camera network (GWAC-N) with the extremely large field of view. After triggered by Insight-HXMT/HE and Fermi/GBM, we observed the optical emission of GRB 190 530A, using the 30 cm telescope of GWAC (GWAC-F30) to search and locate its position. Subsequent observation of the late afterglow of GRB 190 530A was made with the 2.16 m telescope at Xinglong Observatory. In this paper, we make a detailed exploration of the origin of GRB 190 530A. In the prompt emission, a “double-tracking” pattern is presented both for the low-energy spectral index α and the peak energy E p in the Band function with Insight-HXMT/HE and Fermi/GBM data; the results of GRB 190 530A are consistent with the Amati and Yonetoku correlations; the spectral lag (τ) versus energy (E) can be estimated with τ = − 3.0 ± 0.06 + ( 0.17 ± 0.03 ) log E . The synchrotron radiation can account for the origin of GRB 190 530A prompt emission behaviors. The α and E p of the precursor are essentially the same as that of the main prompt emission, implying that they have the same origin. For the afterglow, it can be described with the external forward shock model in ISM circumburst medium. In summary, from precursor, prompt emission to afterglow of GRB 190 530A all originated from synchrotron radiation.
- Published
- 2022
7. Real-time abnormal light curve detection based on a Gated Recurrent Unit network
- Author
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Yan, Rui-Qing, primary, Liu, Wei, additional, Zhu, Meng, additional, Wang, Yi-Jing, additional, Dai, Cong, additional, Cao, Shuo, additional, Wu, Kang, additional, Liang, Yu-Chen, additional, Yu, Xian-Chuan, additional, and Zhang, Meng-Fei, additional
- Published
- 2020
- Full Text
- View/download PDF
8. Ultrathin hybrid absorber based on high-order metamaterial
- Author
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Duong Thi Ha, Nguyen Thi Hien, Vu Dinh Lam, Bui Son Tung, Dinh Ngoc Dung, YoungPak Lee, Liang Yao Chen, Bui Xuan Khuyen, and Vu Thi Hong Hanh
- Subjects
Materials science ,Optics ,business.industry ,Metamaterial ,High order ,business ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Published
- 2021
9. High-performance solution-processed ZnSnO metal–semiconductor–metal ultraviolet photodetectors via ultraviolet/ozone photo-annealing
- Author
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Lian-Kai Xiao, Chun-Ying Huang, Liang-Yu Chen, Guan-Ting Chen, Yun-Hsiang Chang, and Ming-Hsien Li
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Ozone ,Materials science ,business.industry ,Annealing (metallurgy) ,Photodetector ,Condensed Matter Physics ,medicine.disease_cause ,Metal semiconductor ,Electronic, Optical and Magnetic Materials ,Solution processed ,Metal ,chemistry.chemical_compound ,chemistry ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,medicine ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Ultraviolet ,Sol-gel - Published
- 2021
10. Switching between perfect absorption and polarization conversion, based on hybrid metamaterial in the GHz and THz bands
- Author
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Nguyen Van Ngoc, Bui Xuan Khuyen, Dinh Ngoc Dzung, Liang Yao Chen, Thanh Son Pham, Bui Son Tung, YoungPak Lee, Vu Dinh Lam, and Duong Thi Ha
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Materials science ,Acoustics and Ultrasonics ,business.industry ,Terahertz radiation ,Optoelectronics ,Metamaterial ,Condensed Matter Physics ,business ,Polarization (waves) ,Absorption (electromagnetic radiation) ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Abstract
We demonstrate a multifunctional metamaterial (MM) structure which can behave like a perfect absorber (PA) or polarization converter (PC) by controlling the lumped varactor. In PC mode, the MM revealed cross-polarization conversion in a frequency range from 2.0 to 7.0 GHz with a polarization-conversion ratio of nearly 100%. While in the PA state, triple-band high absorption was achieved. In addition, we investigated numerically the PA and PC modes by scaling down the geometrical dimension and orientation of the proposed unit cells, for further development of innovative methods in the THz range. Our work is expected to contribute to the realization of future multifunctional MM-based devices working in the GHz or higher-frequency range.
- Published
- 2021
11. Parametric study of the clustering transition in vibration driven granular gas system*
- Author
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Guanghui Yang, Wei Wang, Lei Yang, Qi-Lin Wu, Liang-Wen Chen, Meiying Hou, Ke-Wei Tao, and Sheng Zhang
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Vibration ,Materials science ,Transition (fiction) ,General Physics and Astronomy ,Statistical physics ,Cluster analysis ,Phase diagram ,Parametric statistics - Abstract
A parametric study of the clustering transition of a vibration-driven granular gas system is performed by simulation. The parameters studied include the global volume fraction of the system, the size of the system, the friction coefficient, and the restitution coefficient among particles and among particle–walls. The periodic boundary and fixed boundary of sidewalls are also checked in the simulation. The simulation results provide us the necessary “heating” time for the system to reach steady state, and the friction term needed to be included in the “cooling” time. A gas-cluster phase diagram obtained through Kolmogorov–Smirnov (K–S) test analysis using similar experimental parameters is given. The influence of the parameters to the transition is then investigated in simulations. This simulation investigation helps us gain understanding which otherwise cannot be obtained by experiment alone, and makes suggestions on the determination of parameters to be chosen in experiments.
- Published
- 2020
12. Realization for dual-band high-order perfect absorption, based on metamaterial
- Author
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Vu Dinh Lam, Liang Yao Chen, YoungPak Lee, Nguyen Thi Hien, Nguyen Thanh Tung, Bui Son Tung, Bui Xuan Khuyen, and Young Ju Kim
- Subjects
Materials science ,Acoustics and Ultrasonics ,business.industry ,Optoelectronics ,Metamaterial ,Multi-band device ,High order ,Condensed Matter Physics ,business ,Absorption (electromagnetic radiation) ,Realization (systems) ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2019
13. Temperature dependence of structural, dynamical, and electronic properties of amorphous Bi2Te3: an ab initio study
- Author
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Yu-Xiang Zheng, R. J. Zhang, Y. R. Guo, Chong Qiao, Wan-Sheng Su, Cai-Zhuang Wang, Kai-Ming Ho, Liang-Yao Chen, Haoting Shen, Jiao Wang, and Songyou Wang
- Subjects
Ab initio molecular dynamics ,Physics ,Chemical physics ,Ab initio ,General Physics and Astronomy ,Local structure ,Amorphous solid ,Electronic properties - Abstract
Bismuth telluride (Bi2Te3) has garnered significant interest in thermoelectric applications and three-dimensional topological insulators due to its unique electronic, transport, and thermal properties. Bi2Te3 and Sb2Te3 chalcogenide compounds have the same crystal structure. While Sb2Te3 has been shown to be a prototypical phase change memory (PCM) compound along the pseudobinary tie-line of Ge-Sb-Te alloys, whether Bi2Te3 can also exhibit PCM functionality is still not well established. In this work, a systematic study on the structural, dynamical, and electronic properties of amorphous Bi2Te3 during the quenching process has been performed by using ab initio molecular dynamics simulations. Pair correlation function, coordination number, bond-angle distribution functions, and a novel atomistic cluster alignment method are used to explore the structural characteristics of Bi2Te3 as a function of temperature. Our study shows that there are many distorted octahedral clusters in amorphous Bi2Te3. In comparison with the local structures in Sb2Te3, we found that the degree of distortion of the octahedrons in the Bi2Te3 system is smaller than that in Sb2Te3 system. Moreover, the changes in the dynamical properties of Bi2Te3 from liquid to glassy state are also explored. The approximate range of liquid-to-glass transition temperature is determined to be between 673 and 723 K. The electronic properties of Bi2Te3 and Sb2Te3 are also analysed by density-of-states and Bader charge calculations, both of them in glass state are semiconductors. Our studies provide useful insights into the local structure and dynamical properties of Bi2Te3 at the atomistic level during the fast cooling process, and suggest that the compound can be a candidate for PCM materials.
- Published
- 2019
14. Analysis On Heat Transfer Characteristics For Bosh Copper Cooling Stave With Shaped Tube
- Author
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Liang-yu Chen and Ye Huo
- Subjects
Materials science ,BOSH ,chemistry.chemical_element ,02 engineering and technology ,01 natural sciences ,Copper ,020501 mining & metallurgy ,0205 materials engineering ,chemistry ,0103 physical sciences ,Heat transfer ,Tube (fluid conveyance) ,Composite material ,010306 general physics - Published
- 2018
15. Multilayered metal-dielectric film structure for highly efficient solar selective absorption
- Author
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Liang Yao Chen, Songyou Wang, Er Tao Hu, Kai Yan Zang, Hai Bin Zhao, David W. Lynch, Jia Jin Zheng, Wei Wei, Rong Jun Zhang, An Qing Jiang, Jun Peng Guo, Xin Xing Liu, Yuan Yao, Zong Jie Tu, Osamu Yoshie, Cai-Zhuang Wang, YoungPak Lee, Yu-Xiang Zheng, and Kehan Yu
- Subjects
Materials science ,Polymers and Plastics ,business.industry ,Transfer-matrix method (optics) ,Metals and Alloys ,02 engineering and technology ,Dielectric ,Sputter deposition ,Radiation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Selective surface ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Absorptance ,Optoelectronics ,Thermal emittance ,0210 nano-technology ,business ,Absorption (electromagnetic radiation) - Abstract
To improve the optical absorptance of a solar selective absorber over a wide wavelength range, an eight-layered metal-dielectric film structure was designed by the transfer matrix method and fabricated with the magnetron sputtering method. The experimental results showed that the multilayered film structure yields a high solar absorptance of 98.3% with excellent spectral selectivity over a wide angular range in the solar radiation region of 250–2000 nm, a total hemispherical emittance of 0.12 at 400 K, and nearly unchanged reflectance after heat treatment at 673 K for 48 h in vacuum, indicating the high efficiency of the photo-to-thermal conversion achieved for the sample to have the potential being practically applied in many fields.
- Published
- 2018
16. Influence of interface layer on optical properties of sub-20 nm-thick TiO2films
- Author
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Juan Liu, Songyou Wang, Rong-Jun Zhang, Da-Hai Li, Yue-Jie Shi, Anquan Jiang, Xin Chen, Liang-Yao Chen, Yu-Xiang Zheng, Yi-Qiang Zhan, and Hong-Liang Lu
- Subjects
010302 applied physics ,Phase transition ,Materials science ,Acoustics and Ultrasonics ,Band gap ,business.industry ,Annealing (metallurgy) ,02 engineering and technology ,Dielectric ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Atomic layer deposition ,chemistry ,Transmission electron microscopy ,0103 physical sciences ,Titanium dioxide ,Optoelectronics ,0210 nano-technology ,business - Abstract
The sub-20 nm ultrathin titanium dioxide (TiO2) films with tunable thickness were deposited on Si substrates by atomic layer deposition (ALD). The structural and optical properties were acquired by transmission electron microscopy, atomic force microscopy and spectroscopic ellipsometry. Afterwards, a constructive and effective method of analyzing interfaces by applying two different optical models consisting of air/TiO2/Ti x Si y O2/Si and air/effective TiO2 layer/Si, respectively, was proposed to investigate the influence of interface layer (IL) on the analysis of optical constants and the determination of band gap of TiO2 ultrathin films. It was found that two factors including optical constants and changing components of the nonstoichiometric IL could contribute to the extent of the influence. Furthermore, the investigated TiO2 ultrathin films of 600 ALD cycles were selected and then annealed at the temperature range of 400–900 °C by rapid thermal annealing. Thicker IL and phase transition cause the variation of optical properties of TiO2 films after annealing and a shorter electron relaxation time reveals the strengthened electron–electron and electron–phonon interactions in the TiO2 ultrathin films at high temperature. The as-obtained results in this paper will play a role in other studies of high dielectric constants materials grown on Si substrates and in the applications of next generation metal-oxide-semiconductor devices.
- Published
- 2018
17. Automatic 3D surface reconstruction and sphericity measurement of micro spherical balls of miniaturized coordinate measuring probes
- Author
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Liang-Chia Chen
- Subjects
Microelectromechanical systems ,Contouring ,Observational error ,business.industry ,Applied Mathematics ,Ranging ,Sphericity ,Optics ,3d mapping ,Ball (bearing) ,business ,Instrumentation ,Engineering (miscellaneous) ,Surface reconstruction ,Mathematics - Abstract
This paper proposes an automatic three-dimensional (3D) surface contouring approach for accurate sphericity evaluation of micro tip balls of coordinate measuring probes using optical measurement and surface reconstruction. In the proposed approach, 3D volumetric data of the tip were constructed from cross-section contours using a 3D mapping algorithm. In addition, a volumetric intersection algorithm was derived from the optical perspective projection principle to remove artefact surface profiles from the volumetric data. A sphericity evaluation method involving minimum zone optimization was also developed to determine the sphericity of the inspected micro tip ball. The developed method is capable of measuring micro spherical balls having a diameter ranging from a few tenths of a micrometre up to several millimetres. An industrial case study was employed to verify the feasibility of the approach. The measurement results demonstrated that the proposed approach could achieve 3D surface reconstruction and evaluate sphericity of micro balls with maximum measurement errors of ±0.5 µm.
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- 2007
18. Dynamic Measurement of Extra Long Stroke Cylinder in the Pneumatic System
- Author
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Liang-Chia Chen, Ho Chang, and Chou-wei Lan
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Control valves ,History ,Engineering ,business.industry ,Quantitative Biology::Tissues and Organs ,Acoustics ,Stick-slip phenomenon ,Pressure sensor ,Computer Science Applications ,Education ,Physics::Fluid Dynamics ,Acceleration ,Control theory ,Control system ,Position-sensing hydraulic cylinder ,Cylinder ,Stroke (engine) ,business - Abstract
This paper sets up the measure and control system of the dynamic characteristics of the extra long stroke cylinder. In the different types of the control conditions (e.g. different control law, operating pressure and direct control valves), using the measure and control system to measure the relation between the pressure and the velocity of the motion of the long stroke cylinder and to observe the stick slip phenomenon of the motion of the long stroke cylinder. In the innovate measurement system, two pressure sensors are set on the long stroke cylinder to measure the difference of the pressure between the inlet and the exhaust of the long stroke cylinder. In additions, a draw line encoder is set on the system to measure the position and the velocity of the motion of the long stroke cylinder. The measuring data of the measure system is transferred to the computer via A/D interface card and counter card, and Home-made program of Haptic Interface Device is used to control the system, saving the data of the motion of the long stroke cylinder. The system uses different types of direction control valve to control the motion of the long stroke cylinder and compares the difference of the motion of the long stroke cylinder. The results show that the motion of the cylinder that pauses in the middle of the cylinder stroke and causes the stick slip phenomenon is more violent than the stick slip phenomenon in other position. When the length of the pause time reaches the some range, the acceleration of the motion of the cylinder will be rised substantially. This paper not only focuses on the testing method of the dynamic characteristics of the motion of the long stroke cylinder, but also includes the analysis of the dynamic characteristics of the motion of the long stroke cylinder. It provides the data of the dynamic characteristics of the motion of the long stroke cylinder to improve and design the pneumatic system of the long stroke cylinder.
- Published
- 2006
19. High-Bandwidth Dynamic Full-Field Profilometry for Nano-Scale Characterization of MEMS
- Author
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Yao-Ting Huang, Liang-Chia Chen, and Pi-Bai Chang
- Subjects
Microelectromechanical systems ,History ,Cantilever ,Materials science ,business.industry ,Bandwidth (signal processing) ,Synchronizing ,Computer Science Applications ,Education ,Vibration ,Superposition principle ,Interferometry ,Optics ,Profilometer ,business - Abstract
The article describes an innovative optical interferometric methodology to delivery dynamic surface profilometry with a measurement bandwidth up to 10MHz or higher and a vertical resolution up to 1 nm. Previous work using stroboscopic microscopic interferometry for dynamic characterization of micro (opto)electromechanical systems (M(O)EMS) has been limited in measurement bandwidth mainly within a couple of MHz. For high resonant mode analysis, the stroboscopic light pulse is insufficiently short to capture the moving fringes from dynamic motion of the detected structure. In view of this need, a microscopic prototype based on white-light stroboscopic interferometry with an innovative light superposition strategy was developed to achieve dynamic full-field profilometry with a high measurement bandwidth up to 10MHz or higher. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterisation of dynamic behaviours of the device. The full-field seventh-mode vibration at a vibratory frequency of 3.7MHz can be fully characterized and nano-scale vertical measurement resolution as well as tens micrometers of vertical measurement range can be performed.
- Published
- 2006
20. Investigation and Modeling of Stress Interactions on 90 nm Silicon on Insulator Complementary Metal Oxide Semiconductor by Various Mobility Enhancement Approaches
- Author
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Wen-Kuan Yeh, Hui Chen Chang, Liang Wei Chen, Cheng Tzung Tsai, M. Ma, Chien-Ting Lin, Che Hua Hsu, Yean-Kuen Fang, Ming Hing Chen, and Tung Hsing Lee
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Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Transistor ,General Engineering ,Oxide ,General Physics and Astronomy ,Silicon on insulator ,law.invention ,Stress (mechanics) ,chemistry.chemical_compound ,CMOS ,chemistry ,law ,Shallow trench isolation ,Optoelectronics ,Wafer ,business ,Leakage (electronics) - Abstract
The interactions of shallow trench isolation (STI) stress and various mobility enhancement approaches in silicon on insulator (SOI) complementary metal oxide semiconductor (CMOS) have been systematically studied. Strong interactions between STI stress and contact etch stop layer (CESL) stress on channel mobility were observed which was attributed to the amplification of CESL channel tensile stress with length of diffusion (LOD) reduction. In this work, an almost completely reversed P-channel metal oxide semiconductor field-effect transistor (PMOSFET) mobility-LOD trend in both /(100) and /(100) oriented SOI wafers was found, which is caused by the reversed polarity of piezoresistance coefficients. On the other hand, charge pumping leakage was enhanced by the post-gate oxide stress (CESL stress) only, and was not affected by any stress applied prior to the gate oxidation step (STI stress).
- Published
- 2006
21. Calibration of 3D surface profilometry using digital fringe projection
- Author
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Chu-Chin Liao and Liang-Chia Chen
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Accuracy and precision ,Contouring ,Observational error ,business.industry ,Applied Mathematics ,Structured-light 3D scanner ,law.invention ,Lens (optics) ,Optics ,law ,Calibration ,Profilometer ,business ,Projection (set theory) ,Instrumentation ,Engineering (miscellaneous) ,Mathematics - Abstract
An effective calibration method, by minimizing measurement errors, has been developed to increase the accuracy of 3D profilometry using digital fringe projection and phase-shifting method. In digital fringe projection, the image intensity and distribution of the sinusoidal fringe patterns projected on the measured surface can be critically affected by lens distortions and image aberrations. The phase difference calculated by the phase-shift principle can be significantly influenced by these error sources and become nonlinear to the optical phase difference (OPD) existing between the surface profiles. This paper demonstrates a 3D calibration method developed to obtain accurate system parameters for 3D surface measurement. The calibration method utilizes a known accurate 3D calibrating block and projection mathematical models for identification of the system parameters by means of least-squares minimization. Accurate clouds of 3D data points can be obtained by a 3D mapping method between the object space and the image coordinates incorporating the phase difference. The measurement accuracy of surface contouring can be maintained well within 2% of the overall measurement range. Verified with the experimental results, the proposed calibration method can effectively reduce more than 60% of the maximum measured error in comparison with the traditional phase-conversion method.
- Published
- 2005
22. Miniaturized 3D surface profilometer using digital fringe projection
- Author
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Liang-Chia Chen and Chung-Chih Huang
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Surface (mathematics) ,Computer science ,business.industry ,Applied Mathematics ,System of measurement ,Resolution (electron density) ,Phase (waves) ,Structured-light 3D scanner ,Optics ,Calibration ,Profilometer ,business ,Instrumentation ,Engineering (miscellaneous) ,Microscale chemistry - Abstract
Three-dimensional measurement systems of high precision have been widely applied in high-technology industries and bio-medical areas, especially for microscale accuracy measurement. However, due to their bulky volume, most of the current surface profilometers cannot perform 3D measurement within a space-restricted inspection environment. To overcome this drawback, a novel 3D surface profilometer with a miniaturized probe was developed according to the digital fringe projection (DFP) principle. Measurement of small objects within a limited space can be made by the profilometer which comprises a digital fringe projection system, coherent image fibres and optical lenses. Using phase shifting and an accurate calibration method, the proposed system can analyse the phase fringe and reconstruct clouds of surface points accurately. An example of 3D intra-oral dental measurement was provided to verify the feasibility and performance of the developed system and techniques. The experimental results indicate that the spatial and vertical measurement resolution can reach 25 µm and 5 µm, respectively, and the accuracy can be controlled within 25 µm, less than 1% of full measurement range.
- Published
- 2005
23. Novel 3-D free-form surface profilometry for reverse engineering
- Author
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Zhi-Xue Huang and Liang-Chia Chen
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Reverse engineering ,Surface (mathematics) ,History ,Engineering ,Engineering drawing ,Contouring ,Laser scanning ,business.industry ,computer.software_genre ,Computer Science Applications ,Education ,Identification (information) ,Computer vision ,Free form ,Artificial intelligence ,Profilometer ,business ,computer ,Surface reconstruction ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
This article proposes an innovative 3-D surface contouring approach for automatic and accurate free-form surface reconstruction using a sensor integration concept. The study addresses a critical problem in accurate measurement of free-form surfaces by developing an automatic reconstruction approach. Unacceptable measuring accuracy issues are mainly due to the errors arising from the use of inadequate measuring strategies, ending up with inaccurate digitised data and costly post-data processing in Reverse Engineering (RE). This article is thus aimed to develop automatic digitising strategies for ensuring surface reconstruction efficiency, as well as accuracy. The developed approach consists of two main stages, namely the rapid shape identification (RSI) and the automated laser scanning (ALS) for completing 3-D surface profilometry. This developed approach effectively utilises the advantages of on-line geometric information to evaluate the degree of satisfaction of user-defined digitising accuracy under a triangular topological patch. An industrial case study was used to attest the feasibility of the approach.
- Published
- 2005
24. Full-field micro surface profilometry using digital fringe projection with spatial encoding principle
- Author
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Ming-Jun Lai, Liang-Chia Chen, and Chui-Chen Liao
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History ,Engineering ,business.industry ,Surface gradient ,Triangulation (computer vision) ,Sharpening ,Computer Science Applications ,Education ,Digital micromirror device ,law.invention ,Structured-light 3D scanner ,Lens (optics) ,Optics ,law ,Computer vision ,Profilometer ,Artificial intelligence ,business ,Structured light - Abstract
This article describes an effective full-field three-dimensional micro surface profilometer using digital fringe projection with digital micromirror device (DMD) technology and triangulation measurement principle. Fast and accurate three-dimensional measurement techniques with full-field measurement capability are thus highly demanded for sharpening product competitiveness. Traditional laser triangulation methods have difficulty in detecting the accurate centre position of projected points or lines when encountered with light scattering problems caused by the object's geometric discontinuities, such as surface boundaries or edges. The newly developed profilometer deploys a DMD to project flexible digital structured light patterns of white light onto the object to suit various inspection requirements, such as the object's size and surface condition. Micro structured light patterns can be generated by using optical zoom and collimating lens sets. Accurate system parameters of 3-D surface profilometry can be obtained by developing a calibration process based on least squares minimization. Micro 3-D contours with a large surface gradient can be reconstructed accurately and efficiently.
- Published
- 2005
25. Development of dynamic 3-D surface profilometry using stroboscopic interferometric measurement and vertical scanning techniques
- Author
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Calvin C. Chang, Chi-Duen Lin, Kuang-Chao Fan, Liang-Chia Chen, Ching-Fen Kuo, and Jung-Tsung Chou
- Subjects
Microelectromechanical systems ,History ,Cantilever ,Materials science ,business.industry ,Synchronizing ,Computer Science Applications ,Education ,law.invention ,Characterization (materials science) ,Vibration ,Interferometry ,Optics ,Optical microscope ,law ,Profilometer ,business - Abstract
The main objective of this technical advance is to provide a single optical interferometric framework and methodology to be capable of delivering both nano-scale static and dynamic surface profilometry. Microscopic interferometry is a powerful technique for static and dynamic characterization of micro (opto) electromechanical systems (M (O) EMS). In view of this need, a microscopic prototype based on white-light stroboscopic interferometry and the white light vertical scanning principle, was developed to achieve dynamic full-field profilometry and characterization of MEMS devices. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterization of dynamic behaviours of the device. The full-field second-mode vibration at a vibratory frequency of 68.60 kHz can be fully characterized and 3–5 nm of vertical measurement resolution as well as tens of micrometers of vertical measurement range can be easily achieved.
- Published
- 2005
26. Using pressure square-like wave to measure the dynamic characteristics of piezoelectric pressure sensor
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Ching-Song Jwo, Liang-Chia Chen, Tsing-Tshih Tsung, Ho Chang, and Lee-Long Han
- Subjects
History ,Materials science ,Acoustics ,Square wave ,Pressure sensor ,Piezoelectricity ,Computer Science Applications ,Education ,law.invention ,Pressure measurement ,law ,Rise time ,Waveform ,Hydraulic machinery ,Bar (unit) - Abstract
Piezoelectric pressure sensors are commonly used to measuring the dynamic characteristics in a hydraulic system. The dynamic measurements require a pressure sensor which has a high response rate. In this paper, we proposed use of a pressure square wave to excite the piezoelectric pressure sensor. Experimental frequencies are 0.5, 1.0, 1.5, and 2.0 kHz at 10, 15, 20 bar, respectively. Results show that the waveform of time-domain and frequencydomain response are quite different under above testing conditions. The higher the frequencies tested, the faster the pressure-rise speeds obtained. Similarly, the higher the testing pressure, the shorter the rise time attained.
- Published
- 2005
27. Analysis of dynamic characteristics of pressure sensors using square pressure wave theory and system identification
- Author
-
Jia Lin Wu, Ho Chang, Liang-Chia Chen, Tsing-Tshih Tsung, and Lee Long Han
- Subjects
Control valves ,Damping ratio ,Materials science ,business.industry ,Applied Mathematics ,Acoustics ,Electrical engineering ,Square wave ,Transfer function ,Pressure sensor ,Square (algebra) ,Hydraulic machinery ,business ,Instrumentation ,Engineering (miscellaneous) ,Voltage - Abstract
Most analyses on pressure sensors focus mainly on their static characteristics, while their dynamic characteristics have rarely been explored. In the field of applied engineering, a pressure sensor with a quick response rate and high stability is required to reflect the dynamic behaviour of the hydraulic system. This study developed a square pressure wave generator to replace the traditional directional control valve. The developed generator can generate a square pressure wave of as high as 2 kHz and can achieve high-frequency switching by utilizing the differential principle through a series of mechanical rotations between the revolving spindle and revolving ring. The square pressure wave generated is input into the hydraulic system while the output voltage signals given by the pressure sensor can be analysed by spectrum analysis and system identification to obtain various dynamic characteristics of the pressure sensor, including transfer function, natural resonance frequency and damping ratio.
- Published
- 2003
28. Enhancement of solar absorption by a surface-roughened metal–dielectric film structure
- Author
-
YoungPak Lee, Yuan Yao, Songyou Wang, Tong Gu, Zi-Yi Wang, Kehan Yu, Yu-Xiang Zheng, Rong-Jun Zhang, Liang-Yao Chen, Shuai Guo, Ertao Hu, Wei Wei, and Kai-Yan Zang
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,General Engineering ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,Substrate (electronics) ,Dielectric ,Sputter deposition ,021001 nanoscience & nanotechnology ,01 natural sciences ,Copper ,Selective surface ,010309 optics ,Metal ,chemistry ,visual_art ,0103 physical sciences ,Absorptance ,visual_art.visual_art_medium ,Optoelectronics ,Thermal emittance ,0210 nano-technology ,business - Abstract
A solar selective absorber with a multilayered SiO2 (87.0 nm)/Cr (8.3 nm)/SiO2 (96.3 nm) film structure was designed and fabricated by magnetron sputtering on a surface-roughened copper (Cu) substrate. The proposed structure can enhance solar absorption by combining both the typical solar absorption designs of the textured surface and metal–dielectric multilayer film structure. The measured solar absorptance is about 94%, which yields an enhancement of about 2% accompanied by a slightly higher thermal emittance than that observed for the surface-smoothed structure. The increasing thermal emittance of the surface-roughened film structure is expected to markedly cancel the advantage of absorptance enhancement as the temperature increases to 600 K, implying that the proposed film structure functions more efficiently at low or intermediate temperatures (
- Published
- 2017
29. Differential interference contrast microscopy using Savart plates
- Author
-
Hưng-Xuân Trịnh, Chin-Sheng Chen, Shyh-Tsong Lin, Sheng-Lih Yeh, and Liang-Chia Chen
- Subjects
Physics ,Afocal photography ,Microscope ,Savart ,business.industry ,Nomarski prism ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Optics ,Differential interference contrast microscopy ,law ,Prism ,Normal surface ,business ,Optical path length - Abstract
A new differential interference contrast microscopy (DICM), which uses Savart prisms as a shearing plate and a phase-shifting device, is proposed. The system consists of a phase-shifting module (PSM) and a DICM module (DICMM). The PSM has two Savart prisms: the first prism separates the incident beam into two parallel beams, and the second prism recombines these two beams. The optical path difference (OPD) of the two beams, which is represented by a biased OPD, can be adjusted by rotating the angle of the normal surface of the second prism. In the DICMM, the other Savart prism is used to replace the Nomarski prism (NP) in conventional DICM. It combines with an afocal microscopic system (AMS) to produce a Savart-DICM system, which is able to perform a phase-shifting technique by changing the biased OPD to produce a phase shift of π/2 for each step. This paper describes the configuration and measurement theory of the microscope. The experimental results confirm the validity and capability of the proposed microscope.
- Published
- 2017
30. Microstructure and corrosion behavior of a Zr-Sn-Nb-Fe-Cu-O alloy fabricated by α+β quenching processing
- Author
-
Weijie Lu, Liang-Yu Chen, Linjiang Chai, Liqiang Wang, Lina Zhang, and Wenlong Yang
- Subjects
010302 applied physics ,Materials science ,Scanning electron microscope ,Annealing (metallurgy) ,Alloy ,Oxide ,Analytical chemistry ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Corrosion ,chemistry.chemical_compound ,Crystallography ,chemistry ,Transmission electron microscopy ,0103 physical sciences ,engineering ,0210 nano-technology ,Electron backscatter diffraction - Abstract
In this work, the microstructure of a Zr-Sn-Nb-Fe-Cu-O alloy fabricated by α+β quenching processing (ABQ sample) was investigated by the combined utilization of scanning electron microscopy, electron backscatter diffraction and transmission electron microscopy. The results showed that the polygonal grains evenly distributed in ABQ sample and triangular grains distributed at triple junctions of polygonal grains with densely second phase particles (SPPs). The textures of directions tilted approximately 25° from normal direction and the rolling direction spreading along the were found in the sample, which was also detected in the regularly cold rolled and annealed sample. The occurrence of corrosion kinetics transition of ABQ sample was sight earlier than that of RAX sample. Due to a higher solid solubility of β-Zr, SPPs re-dissolved into β-Zr during α+β annealing and precipitated out afterward in those areas. Finally, discrepant corrosion rate of metal matrix and SPPs led to the formation of protrusions of matrix, which could concentrate stress and generate cracks in the oxide.
- Published
- 2017
31. Sub-OBB based object recognition and localization algorithm using range images
- Author
-
Thanh-Hung Nguyen, Liang-Chia Chen, and Dinh-Cuong Hoang
- Subjects
Computer science ,Applied Mathematics ,3D single-object recognition ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Cognitive neuroscience of visual object recognition ,Iterative closest point ,02 engineering and technology ,021001 nanoscience & nanotechnology ,3D pose estimation ,Object (computer science) ,01 natural sciences ,010309 optics ,0103 physical sciences ,Object model ,Viola–Jones object detection framework ,0210 nano-technology ,Instrumentation ,Engineering (miscellaneous) ,Pose ,Algorithm - Abstract
This paper presents a novel approach to recognize and estimate pose of the 3D objects in cluttered range images. The key technical breakthrough of the developed approach can enable robust object recognition and localization under undesirable condition such as environmental illumination variation as well as optical occlusion to viewing the object partially. First, the acquired point clouds are segmented into individual object point clouds based on the developed 3D object segmentation for randomly stacked objects. Second, an efficient shape-matching algorithm called Sub-OBB based object recognition by using the proposed oriented bounding box (OBB) regional area-based descriptor is performed to reliably recognize the object. Then, the 3D position and orientation of the object can be roughly estimated by aligning the OBB of segmented object point cloud with OBB of matched point cloud in a database generated from CAD model and 3D virtual camera. To detect accurate pose of the object, the iterative closest point (ICP) algorithm is used to match the object model with the segmented point clouds. From the feasibility test of several scenarios, the developed approach is verified to be feasible for object pose recognition and localization.
- Published
- 2016
32. Optical constants of e-beam evaporated and annealed Nb2O5thin films with varying thickness
- Author
-
Songyou Wang, Qing-Yuan Cai, Jin-Bo Zhang, Liao Yang, Yu-Xiang Zheng, Dong-Dong Zhao, Zhun-Hua Liu, Shang-Dong Yang, Liang-Yao Chen, and Rong-Jun Zhang
- Subjects
Materials science ,Acoustics and Ultrasonics ,Annealing (metallurgy) ,business.industry ,Analytical chemistry ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,01 natural sciences ,Electron beam physical vapor deposition ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,chemistry.chemical_compound ,Optics ,chemistry ,Electron beam processing ,Orthorhombic crystal system ,Niobium pentoxide ,Thin film ,0210 nano-technology ,business - Abstract
Niobium pentoxide (Nb2O5) films with different thicknesses were prepared using the electron beam evaporation method and then annealed at temperatures from 300 °C to 800 °C before being characterized by variable-angle spectroscopic ellipsometry, x-ray diffraction, etc. The results showed that the optical constants and microstructures of Nb2O5 films exhibit a strong dependence on the annealing temperature. In the visible light region, the refractive indices show a positive correlation with the annealing temperature from 300 °C to 600 °C, but a negative correlation from 600 °C to 800 °C. The amorphous Nb2O5 film converts into TT- Nb2O5 (pseudo-hexagonal) after annealing at 500–600 °C, and into T-Nb2O5 (orthorhombic) after annealing at 700–800 °C.
- Published
- 2016
33. Study on electrical defects level in single layer two-dimensional Ta 2 O 5
- Author
-
Xiongfei Song, Linfeng Hu, David Wei Zhang, Zi-Yi Wang, Peng Zhou, Rong-Jun Zhang, Da-Hai Li, and Liang-Yao Chen
- Subjects
Materials science ,business.industry ,Gate dielectric ,General Physics and Astronomy ,02 engineering and technology ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electron spectroscopy ,Crystallographic defect ,0104 chemical sciences ,Optics ,X-ray photoelectron spectroscopy ,Ellipsometry ,Optoelectronics ,Field-effect transistor ,0210 nano-technology ,business ,Spectroscopy - Abstract
Two-dimensional atomic-layered material is a recent research focus, and single layer Ta2O5 used as gate dielectric in field-effect transistors is obtained via assemblies of Ta2O5 nanosheets. However, the electrical performance is seriously affected by electronic defects existing in Ta2O5. Therefore, spectroscopic ellipsometry is used to calculate the transition energies and corresponding probabilities for two different charged oxygen vacancies, whose existence is revealed by x-ray photoelectron spectroscopy analysis. Spectroscopic ellipsometry fitting also calculates the thickness of single layer Ta2O5, exhibiting good agreement with atomic force microscopy measurement. Nondestructive and noncontact spectroscopic ellipsometry is appropriate for detecting the electrical defects level of single layer Ta2O5.
- Published
- 2016
34. Structural and optical properties of Ge60Te40: experimental and theoretical verification
- Author
-
F. Dong, Chaochao Liu, Wan-Sheng Su, Jun Wang, Liang-Yao Chen, Zhanyu Wang, Songyou Wang, Shuai Cheng, Tieying Yang, Jing Li, and Xinyu Yi
- Subjects
Materials science ,Acoustics and Ultrasonics ,Mechanical engineering ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Calculation methods ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Germanium compounds ,0103 physical sciences ,010306 general physics ,0210 nano-technology ,Tellurium compounds - Published
- 2016
35. Multi-plasmon-induced perfect absorption at the third resonance in metamaterials
- Author
-
Young Joon Yoo, Liang-Yao Chen, Ki Won Kim, Hyeonsik Cheong, Jung-ock Park, Youn-Hyun Kim, P. V. Tuong, Y. P. Lee, and Y H Kim
- Subjects
Yield (engineering) ,Materials science ,business.industry ,Plane (geometry) ,Physics::Optics ,Metamaterial ,Resonance ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optics ,Dielectric layer ,Metamaterial absorber ,business ,Absorption (electromagnetic radiation) ,Plasmon - Abstract
We numerically and experimentally investigated a strategy for property enhancement in the conventional metamaterial absorber, which includes periodic metal cut-wires at the front separated from the metal plane at the back by a dielectric layer. The third resonance in the meta-atom, which was induced by the magnetic multi-plasmon, was exploited to yield a perfect-absorption peak by manipulating the structural parameters. The electromagnetic properties were examined in comparison with the conventional strategy at the first resonance. By taking full advantage of the higher frequency of the multi-plasmonic resonance, the perfect absorption was demonstrated even in mid-infrared and visible regimes.
- Published
- 2015
36. Viewpoint-independent 3D object segmentation for randomly stacked objects using optical object detection
- Author
-
Liang-Chia Chen, Thanh-Hung Nguyen, and Shyh-Tsong Lin
- Subjects
Computer science ,business.industry ,Applied Mathematics ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Process (computing) ,Point cloud ,Boundary (topology) ,Object (computer science) ,Object detection ,Transformation (function) ,Optics ,Depth map ,Computer vision ,Segmentation ,Artificial intelligence ,business ,Instrumentation ,Engineering (miscellaneous) - Abstract
This work proposes a novel approach to segmenting randomly stacked objects in unstructured 3D point clouds, which are acquired by a random-speckle 3D imaging system for the purpose of automated object detection and reconstruction. An innovative algorithm is proposed; it is based on a novel concept of 3D watershed segmentation and the strategies for resolving over-segmentation and under-segmentation problems. Acquired 3D point clouds are first transformed into a corresponding orthogonally projected depth map along the optical imaging axis of the 3D sensor. A 3D watershed algorithm based on the process of distance transformation is then performed to detect the boundary, called the edge dam, between stacked objects and thereby to segment point clouds individually belonging to two stacked objects. Most importantly, an object-matching algorithm is developed to solve the over- and under-segmentation problems that may arise during the watershed segmentation. The feasibility and effectiveness of the method are confirmed experimentally. The results reveal that the proposed method is a fast and effective scheme for the detection and reconstruction of a 3D object in a random stack of such objects. In the experiments, the precision of the segmentation exceeds 95% and the recall exceeds 80%.
- Published
- 2015
37. Magneto-Optical Properties of PtCu/Co Multilayers
- Author
-
Liang-yao Chen, Jinchang Chen, Jian Li, Wu Zheng, Ping-ping Ma, Yin-jun Wang, and Ailing Wang
- Subjects
Wavelength ,Materials science ,Condensed matter physics ,Oscillation ,Superlattice ,General Physics and Astronomy ,Polar ,Rotation ,Anisotropy ,Spin (physics) ,Refractive index - Abstract
The effect of Cu doping in Pt spacer layers on the magneto-optical properties of sputtered Pt/Co multilayers has been investigated. It was found that the polar Kerr rotation θk, ellipticity k, refractive index n and absorptive index k show an oscillation behavior as a function of the Cu content x, reflective index R keeps almost constant with the decreasing wavelength λ, three θk peaks appear at x = 0.03, 0.12, 0.25, respectively. Values of conductivity tensor σ1xx, σ2xx, σ1xy, and σ2xy in the PtCu layers have been derived from experimental θk, k, n, and k values at wavelength 770 nm. The oscillation of the polar Kerr rotation θk may be resulted from spin polarized quantum size effects in the PtCu layers.
- Published
- 1998
38. Studies on CsBr with Synchrotron Radiation Under Ultrahigh Pressure up to 115 GPa
- Author
-
Liang-chen Chen, Lijun Wang, Fengying Li, Rong-zheng Che, Lei Zhou, and Hui-cheng Gu
- Subjects
Diffraction ,Phase transition ,Materials science ,business.industry ,Synchrotron Radiation Source ,Analytical chemistry ,General Physics and Astronomy ,Synchrotron radiation ,Cubic crystal system ,Diamond anvil cell ,Metal ,Tetragonal crystal system ,Optics ,visual_art ,visual_art.visual_art_medium ,business - Abstract
In situ high pressure energy dispersive x-ray diffraction experiments have been carried out on CsBr by using diamond anvil cell device with synchrotron radiation source. The maximum pressure is 115 GPa. The structure of CsBr is changed from simple cubic phase to tetragonal phase at pressure about 53 GPa, marked by the splitting of its strongest diffraction line (110). At pressure above 98 GPa, the color change of CsBr from transparent to red-brown was observed. No pressure-induced transition from insulator to metal is found at higher pressure up to 115 GPa.
- Published
- 1998
39. Speckled ZnO Nanograss Electrochemical Sensor for Staphylococcus epidermidis Detection.
- Author
-
Purwidyantri, Agnes, Ching-Hsiang Chen, Liang-Yih Chen, Chien-Chung Chen, Ji-Dung Luo, Chiuan-Chian Chiou, Ya-Chung Tian, Chan-Yu Lin, Chia-Ming Yang, Hsin-Chih Lai, and Chao-Sung Lai
- Subjects
ELECTROCHEMICAL sensors ,BACTERIAL DNA ,STAPHYLOCOCCUS epidermidis - Abstract
Zinc oxide nanograss (ZnONG) decorated with gold (Au) nanospeckles is demonstrated as a sensing platform for bacterial DNA hybridization in this study. Thermal evaporation of 5 nm Au on hydrothermally synthesized ZnONG generates highly dense speckles, which contributes to an approximately two-fold enhancement of the effective surface area and diffusion coefficient in cyclic voltammetry (CV) measurement compared to the non-speckled nanograss. Selective capture of molecular probes from our predesigned sequence of S. epidermidis 16S rRNA onto nanospeckled ZnONG indicated a specific interaction with the DNA target from this prevalently isolated skin pathogen through hybridization screening. The fabricated DNA biosensor demonstrated great ability to quantify a wide range of complementary DNA target, from 10 pM to 1 µM. Moreover, it attained an impressive limit of detection (LOD) of 0.506 pM, as determined by the charge-transfer resistance (R
CT ), upon DNA hybridization in an electrochemical impedance spectroscopy (EIS) analysis. The proposed structure of the hybrid Au-speckled ZnONG effectively improved the electro-catalytic properties and electron migration of electrochemical DNA detection due to the increment of the surface area, which consequently renders this structure a potential platform for array-based DNA sensor development. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
40. Pressure-Induced Amorphous Transition of Li 2 Ge 7 O 15 Crystal
- Author
-
Guo-xiang Lan, Liang-chen Chen, Rong-zheng Che, Fengying Li, Li-song Xiu, Hui-cheng Gu, Lei Zhou, and Lijun Wang
- Subjects
Diffraction ,Phase transition ,Materials science ,Atmospheric pressure ,business.industry ,Analytical chemistry ,General Physics and Astronomy ,Internal pressure ,Crystal structure ,Diamond anvil cell ,Amorphous solid ,Optics ,Orthorhombic crystal system ,business - Abstract
Pressure-induced amorphous transition of Li2Ge7O15 (LGO) crystal has been investigated by using in situ high pressure energy dispersive x-ray diffraction with synchrotron radiation at the pressure up to 21.6 GPa. Diamond anvils were used to generate high pressure. Pressure was measured in terms of the diffraction of Pt as an internal pressure standard. The crystal structure of LGO is an orthorhombic lattice at atmospheric pressure. According to the high pressure x-ray diffraction results, new diffraction lines begin to appear and LGO undergoes an intermediate phase transition at the pressure of 12.9 GPa. But, the diffraction lines disappear wholly and LGO becomes an amorphous phase at the pressure of above 14.8 GPa. This amorphous transition is irreversible.
- Published
- 1996
41. In-situ volumetric topography of IC chips for defect detection using infrared confocal measurement with active structured light
- Author
-
Manh-Trung Le, Dao Cong Phuc, Liang-Chia Chen, and Shyh-Tsong Lin
- Subjects
Materials science ,business.industry ,Infrared ,Semiconductor device fabrication ,Applied Mathematics ,Integrated circuit ,Chip ,law.invention ,Optics ,Clipping (photography) ,law ,Measured depth ,Integrated circuit packaging ,business ,Instrumentation ,Engineering (miscellaneous) ,Structured light - Abstract
The article presents the development of in-situ integrated circuit (IC) chip defect detection techniques for automated clipping detection by proposing infrared imaging and full-field volumetric topography. IC chip inspection, especially held during or post IC packaging, has become an extremely critical procedure in IC fabrication to assure manufacturing quality and reduce production costs. To address this, in the article, microscopic infrared imaging using an electromagnetic light spectrum that ranges from 0.9 to 1.7 µm is developed to perform volumetric inspection of IC chips, in order to identify important defects such as silicon clipping, cracking or peeling. The main difficulty of infrared (IR) volumetric imaging lies in its poor image contrast, which makes it incapable of achieving reliable inspection, as infrared imaging is sensitive to temperature difference but insensitive to geometric variance of materials, resulting in difficulty detecting and quantifying defects precisely. To overcome this, 3D volumetric topography based on 3D infrared confocal measurement with active structured light, as well as light refractive matching principles, is developed to detect defects the size, shape and position of defects in ICs. The experimental results show that the algorithm is effective and suitable for in-situ defect detection of IC semiconductor packaging. The quality of defect detection, such as measurement repeatability and accuracy, is addressed. Confirmed by the experimental results, the depth measurement resolution can reach up to 0.3 µm, and the depth measurement uncertainty with one standard deviation was verified to be less than 1.0% of the full-scale depth-measuring range.
- Published
- 2014
42. 3-D micro surface profilometry employing novel Mirau-based lateral scanning interferometry
- Author
-
Yi-Shiuan Lin, Manh-Trung Le, and Liang-Chia Chen
- Subjects
White light interferometry ,Materials science ,business.industry ,Applied Mathematics ,Field of view ,Interferometry ,Optics ,White light scanner ,Astronomical interferometer ,Calibration ,Coherence (signal processing) ,Profilometer ,business ,Instrumentation ,Engineering (miscellaneous) - Abstract
An innovative 3-D surface imaging methodology for reconstructing micro surface profiles with a long depth measuring range and a nano-scale resolution was developed using the newly developed Mirau-based lateral scanning interferometry (LSI). The current measuring field of view (FOV) of conventional white light interferometers is limited by microscopic views of the existing interferometric objectives, such as those in Michelson, Mirau or Linnik designs. Moreover, the vertical scanning operation required for acquiring volumetric interferometric data is extremely time-consuming and makes white light vertical scanning interferometry (VSI) infeasible for automatic optical inspection (AOI) of micro 3-D structures. To resolve this, a newly developed white light LSI method based on Mirau’s optical configuration was developed by controlling the tilting angle of the reference mirror in the Mirau interferometric objective. With the proposed optical configuration, the surface is inspected at a tilting angle with respect to the maximum coherence plane of the interferometric system along its lateral scanning direction when the objective lies perpendicular to the tested surface. In addition, a system calibration method was developed to establish an accurate mathematical mapping model between the object depth and the lateral axis. To evaluate the feasibility of the methodology, a calibrated step height was measured for evaluating the accuracy and repeatability. Some industrial samples, such as photon spacers and other microstructures fabricated by nano-imprinting processes, were measured to verify the actual performance on real components. It was found that the measurement repeatability was controlled less than 60 nm within one standard deviation for a maximum measurable depth of 27.21 µm.
- Published
- 2014
43. Temperature-Dependent Optical Properties of Titanium Oxide Thin Films Studied by Spectroscopic Ellipsometry
- Author
-
Yan Sun, Rong-Jun Zhang, Ning Dai, Ren-Zhong Huang, Yu-Xiang Zheng, Ji-Ping Xu, Liang-Yao Chen, Xiang-Jian Meng, Zi-Yi Wang, Fan Zhang, Xin Chen, and Dong-Xu Zhang
- Subjects
Materials science ,Silicon ,Band gap ,General Engineering ,Analytical chemistry ,Physics::Optics ,General Physics and Astronomy ,chemistry.chemical_element ,Substrate (electronics) ,Atmospheric temperature range ,Evaporation (deposition) ,Condensed Matter::Materials Science ,Absorption edge ,chemistry ,Atomic electron transition ,Thin film - Abstract
The electron-beam evaporation method was devoted to fabricate anatase-phase TiO2 thin films on silicon substrate. The optical constants of the thin films determined by spectroscopic ellipsometry in the spectral range from 300 to 800 nm were studied in a temperature range from 293 to 533 K. The refractive indices decrease apparently with increasing temperature, and the thermal expansion and electron–phonon interaction can be introduced to elucidate this phenomenon. The absorption edge in extinction coefficient spectra shows a redshift at elevated temperature, which is attributed to thermally driven band gap shrinkage and electron lifetime loss of optical electron transition.
- Published
- 2013
44. Theoretical simulation and experimental confirmation of duty cycle effect on stroboscopic white light interferometry for M(O)EMS dynamic characterization
- Author
-
Abraham Mario Tapilouw and Liang-Chia Chen
- Subjects
Physics ,Microelectromechanical systems ,White light interferometry ,business.industry ,Mechanical Engineering ,Vibration amplitude ,Stroboscope ,Electronic, Optical and Magnetic Materials ,Characterization (materials science) ,Optics ,Mechanics of Materials ,Duty cycle ,White light ,Electrical and Electronic Engineering ,business ,Beam (structure) - Abstract
Stroboscopic white light interferometry (SWLI) has been known as a useful measurement technique for vibrating samples such as micro-electro-mechanical systems (MEMS) or micro-opto-electro-mechanical systems (M(O)EMS) because it enables dynamic mode reconstruction and characterization of the tested system. An approximate model simulation without any experimental confirmation previously indicated that the duty cycle of the light could reduce the accuracy of the measurement. To provide a comprehensive insight into this important phenomenon, the study investigated theoretically and experimentally the effect of duty cycle of the light. An atomic force microscopy cantilever beam vibrating at its second resonant frequency was measured and the experimental measurements were analyzed and compared with the simulated results. In general, a reasonable correspondence between the mathematical model and the experimental measurements has been observed when the duty cycle is less than 15% and the average deviation is kept within 15.4% of the vibration amplitude. However, it is verified that the SWLI using white light LED has its physical detection limits when the cycle time of the strobed light or the light exposure time of the imaging device is more than 20%, in which the maximum measured error can significantly exceed 38.4% of the vibration amplitude.
- Published
- 2013
45. Photoinduced Spin Precession in Fe/GaAs(001) Heterostructure with Low Power Excitation
- Author
-
Haochen Yuan, Yuhang Ren, Jun Lu, Xinhui Zhang, Haibin Zhao, Haixia Gao, Yu Gong, Liang-Yao Chen, and Jianhua Zhao
- Subjects
Materials science ,Condensed matter physics ,General Engineering ,Physics::Optics ,General Physics and Astronomy ,Schottky diode ,Heterojunction ,Magnetic field ,Condensed Matter::Materials Science ,Depletion region ,Excited state ,Precession ,Spin (physics) ,Excitation - Abstract
Pronounced spin precessions are observed in Fe films grown on n-doped GaAs(001) with a tailored Schottky interface under low-energy ultrafast laser excitation, more than two orders of magnitude smaller than typically required in heat-induced excitation. Pump wavelength dependence of the precession amplitude shows that the fast drift of the optically excited free carriers in the narrow depletion layer of GaAs is the key mechanism to generate the significant transient magnetic field triggering spin precessions.
- Published
- 2013
46. Room-Temperature Continuous-Wave Operation of InGaN-Based Blue-Violet Laser Diodes with a Lifetime of 15.6 Hours
- Author
-
Chang, Zeng, primary, Shu-Ming, Zhang, additional, Lian, Ji, additional, Huai-Bing, Wang, additional, De-Gang, Zhao, additional, Jian-Jun, Zhu, additional, Zong-Shun, Liu, additional, De-Sheng, Jiang, additional, Qing, Cao, additional, Ming, Chong, additional, Li-Hong, Duan, additional, Hai, Wang, additional, Yong-Sheng, Shi, additional, Su-Ying, Liu, additional, Hui, Yang, additional, and Liang-Hui, Chen, additional
- Published
- 2010
- Full Text
- View/download PDF
47. Study on tapered crossed subwavelength gratings by Fourier modal method
- Author
-
Xi, Chen, primary, Yuan, Zhong, additional, Qing, Wang, additional, Ye-Jin, Zhang, additional, and Liang-Hui, Chen, additional
- Published
- 2010
- Full Text
- View/download PDF
48. Polarization dependent solar cell conversion efficiency at oblique incident angles and the corresponding improvement using surface nanoparticle coating
- Author
-
Jian-Jang Huang, Liang-Yu Su, Shao-Sun Hsu, Chun-Hsiang Chang, Yu-Ting Wang, Yen-Jen Hung, and Liang-Yi Chen
- Subjects
Materials science ,business.industry ,Mechanical Engineering ,Energy conversion efficiency ,Physics::Optics ,Nanoparticle ,Bioengineering ,General Chemistry ,Ray ,Spectral line ,law.invention ,Transverse plane ,Optics ,Mechanics of Materials ,law ,Monolayer ,Solar cell ,Optoelectronics ,General Materials Science ,Electrical and Electronic Engineering ,business ,Refractive index - Abstract
Despite tremendous efforts on improving the solar cell conversion efficiency at normal incidence, improvement at oblique angles has not been widely addressed, not to mention the corresponding light absorption behaviors at different polarizations. Here we report the characterization of the solar cell conversion efficiency and the spectra of photoresponsivity at various tilted angles. The results show that TM (transverse magnetic) polarized light possesses higher photoresponsivity than TE (transverse electric) polarized light and the difference becomes larger with the incidence angle. To address the issue, a monolayer of silica nanoparticles on the solar cell surface was employed to improve the light absorption. Even though both TE and TM waves show a decrease in the surface reflectivity with the presence of nanoparticles, the interaction between the silica particles and the TE wave is more significant. The improvement of the conversion efficiency for obliquely incident light is explained from the refractive index difference of the nanoparticles for the TE and TM polarizations.
- Published
- 2011
49. Evolution of Ring Current Protons Induced by Electromagnetic Ion Cyclotron Waves
- Author
-
Fu-Liang, Xiao, primary, Tian, Tian, additional, Liang-Xu, Chen, additional, Zhen-Peng, Su, additional, and Hui-Nan, Zheng, additional
- Published
- 2009
- Full Text
- View/download PDF
50. Fabrication of 3D Templates Using a Large Depth of Focus Femtosecond Laser
- Author
-
Xiao-Fan, Li, primary, Richard, Winfield, additional, Shane, O'Brien, additional, and Liang-Yao, Chen, additional
- Published
- 2009
- Full Text
- View/download PDF
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