Browsing by Author "Chen, Tse-Yu"

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Anterior bone loss after cervical Bryan disc arthroplasty: insight into the biomechanics following total disc replacement
(2020-08-01)
Chen, Tse-Yu
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Chen, Wen-Hsien
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Tzeng, Chung-Yuh
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Huang, Chi-Wei
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Yang, Chih-Chang
BACKGROUND CONTEXT: Cervical disc arthroplasty (CDA) is an innovative procedure launched in the early 2000s. Compared with anterior cervical discectomy and fusion, many studies show that CDA offers equivalent clinical outcomes while reducing secondary procedures and total cost. PURPOSE: We sought to determine the incidence of anterior bone loss after CDA and the related biomechanical effects. STUDY DESIGN/SETTING: Retrospective chart review. PATIENT SAMPLE: Patients who underwent CDA with one level Bryan Disc (Medtronic SofamorDanek, Memphis, TN, USA) at one institution. OUTCOME MEASURES: Radiological measurements, including the extent of anterior bone loss, global alignment angle, shell angle, lordotic angle, mean degree of angle of the endplate with the horizontal line, global range of motion (ROM) and ROM of the index level were recorded. The grading of anterior bone loss of the index level was defined as Grade 0, no remodeling; Grade 1, spur disappearance or mild change in body contour; Grade 2, obvious bone regression with Bryan Disc exposure. METHODS: Anatomical measures and ROM were compared by grade of bone loss. RESULTS: Of the 121 patients included in the study, anterior bone loss was found in 53 (43.8%) on the upper adjacent level and 54 (44.6%) on the lower adjacent level. Twenty-nine patients (23.9%) had anterior bone loss in both levels. The majority of cases had Grade 1 anterior bone loss. Grade 2 bone loss was noted in the upper adjacent vertebra in only 5 patients and in 4 patients in the lower adjacent vertebra. Age, sex, operative level, and hybrid surgery had no effect on anterior bone loss. Most radiological assessments, including global alignment angle, lordotic angle, mean degree of angle of the endplate with the horizontal line, global ROM, and ROM of the index level, showed no correlation to anterior bone loss. Shell angle was found to be different in groups with or without remodeling in the upper adjacent level: 5.0 degreesin the Grade 0 group and 7.0 degrees in the Grade 1-2 group, p<. 05. CONCLUSIONS: Many more patients than predicted had anterior bone loss. Increasing the shell angle of the artificial disc may increase the incidence of anterior bone loss after CDA. Further study of the biomechanics following CDA should help clarify the mechanisms at work. (c) 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license. (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Bandwidth-Enhanced Branch-Line Coupler Using the Center-Loaded Vertical Line and Distributed Capacitors
(2012)
Chen, Tse-Yu
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Chi, Pei-Ling
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電機資訊學士班
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Undergraduate Honors Program of Electrical Engineering and Computer Science
In this paper, the technique that loads the center of the horizontal transmission lines in a conventional branch-line coupler by a vertical line section as well as the distributed capacitors is presented to enhance the coupler bandwidths. Based on the proposed structure, the numerical solution derived from the even/odd-mode decomposition analysis for optimized bandwidth enhancement is applied for structural parameters. Experimental results show that the developed 90 degrees coupler demonstrates more than 11% return-loss/isolation bandwidth increase as compared to the conventional quadrature hybrid. Furthermore, the 3dB +/- 1dB magnitude- and 90 degrees +/- 5 degrees phase-difference bandwidths are 3% and 14% increased, respectively.
Dual-Band Ring Coupler Based on the Composite Right/Left-Handed Folded Substrate-Integrated Waveguide
(2014-05-01)
Chi, Pei-Ling
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Chen, Tse-Yu
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電機資訊學士班
;
Undergraduate Honors Program of Electrical Engineering and Computer Science
In this letter, a dual-band ring coupler based on the folded substrate-integrated waveguide (FSIW) is proposed. The artificial structure, the composite right/left-handed (CRLH) transmission lines were implemented in the FSIW by loading the interdigital capacitors in the middle metallic layer to generate a left-handed passband region below the cutoff frequency of the ordinary waveguide mode for coupler miniaturization. The FSIW is the folded counterpart of the substrate-integrated waveguide (SIW) and thus can prevent the CRLH transmission lines from radiation loss by shielding the interdigital capacitors in the waveguide. Besides, the FSIW-based coupler is able to eliminate the electromagnetic interference (noise) with adjacent objects and lend itself to multilayer circuit integration. A ring coupler that operates at 4.3 and 7.6 GHz was developed and experimentally verified. To the best of the authors\' knowledge, it is the first time that a dual-band rat-race was implemented and reported based on the CRLH-FSIW structure.
Miniaturized Branch-Line Coupler with Coupling-Dependent Dual-Frequency Operation
(2013)
Chen, Tse-Yu
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Chi, Pei-Ling
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Lin, Ting-Tsan
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資訊工程學系
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Department of Computer Science
A miniaturized branch-line coupler that is able to operate at two arbitrary frequencies is presented in this paper. The dual-band frequency ratio depends on the coupling coefficient in the proposed transmission line element. It will be shown later that the dual-band separation decreases as the coupling strength increases. By replacing the traditional quarter-wavelength lines with the proposed artificial transmission lines of a prescribed coupling coefficient, a size-reduced branch-line coupler can be implemented at dual frequencies of interest. An example of the 0.9-and 1.8-GHz branch-line coupler, which corresponds to a band ratio of 2, is experimentally developed and characterized. The presented coupler occupies only 44% footprint of the conventional coupler operating at the lower frequency of the dual-band operation. Excellent agreement between the simulated and measured results is obtained.