Browsing by Author "Chang, Shih-Hsien"

Now showing 1 - 5 of 5

A silicon monolithic phase-inverter rat-race coupler using spiral coplanar striplines and its application in a broadband Gilbert mixer
(2008-08-01)
Tseng, Sheng-Che
;
Meng, Chinchun
;
Chang, Chia-Hung
;
Chang, Shih-Hsien
;
Huang, Guo-Wei
This paper realized a broadband uniplanar phase-inverter rat-race coupler using a standard silicon process, and then analyzed this coupler under a lossy condition. A phase inverter is employed in this coupler, not only to extend the operation bandwidth, but also to generate balanced outputs by providing equal lossy paths, while symmetrical spiral-shaped coplanar striplines (CPSs) are also utilized to shrink the coupler size, as well as to construct a phase inverter in the middle of one of spiral CPSs. The lossy CPS, when designed as a distortionless line, has a real characteristic impedance, and thus, perfect port matching of the coupler can be achieved at the center frequency. The operation frequency of this silicon monolithic rat-race coupler with the size of 0.5 mm(2) is extremely wide and ranges from 5 to 23 GHz. The dissipated loss, transmission coefficient, and isolation of the rat-race coupler are approximately 5.5, -8, and below -25 dB, respectively. In addition, a wideband Gilbert micromixer with an integrated uniplanar phase-inverter rat-race coupler at the local oscillator port is demonstrated using 0.35-mu m SiGe BiCMOS technology. This mixer works from 2.5 to 13 GHz with 12-dB conversion gain, -16-dBm IP(1) (dB), -4-dBm IIP(3), and 14-dB noise figure. The chip size of the mixer with an integrated coupler is approximately 1.4 mm x 1.4 mm.
Detoxification of nicotine solution using Fe-0-based processes: Toxicity evaluation by Daphnia magna neonate and embryo assays
(2018-01-01)
Chen, Kuei-Fang
;
Huang, Sin-Yi
;
Chung, Yu-Ta
;
Wang, Kai-Sung
;
Wang, Chih-Kai
Three Fe-0-based techniques were used to treat wastewater containing nicotine. Daphnia magna neonates and embryos were used in bioassays to evaluate the toxicity of nicotine before and after the treatments. The results show that nicotine was highly toxic to Daphnia neonates (EC50, 48h = 0.379 mg L-1, EC50, 72h = 0.125 mg L-1). Although nicotine was moderately toxic to Daphnia embryos after a 48 h exposure (EC50, 48h = 250.8 mg L-1), nicotine was highly toxic to the embryos (EC50, 72h = 1.328 mg L-1) when exposure time was extended to 72 h. Nicotine induced malformations in the second antenna, carapace, and tail spine. The Fe-0/air process was unable to effectively degrade nicotine. In contrast, the Fe-0/H2O2 process and micro-electrolysis efficiently removed nicotine within 30 min (90.8% and 94.6%, respectively). The chemical oxygen demand removed by microelectrolysis (70.4%) was clearly higher than that removed by the Fe-0/H2O2 technique (58.1%). Micro-electrolysis maintained its effectiveness (> 81.3%) after seven reuse cycles. A spectral analysis indicated that the micro-electrolysis process effectively removed the pyridine (A(260)) and pyrrolidine rings (A(206)) of nicotine. The toxicity of Fe-0/H2O2-and micro-electrolysis-treated solutions were low (3.75% embryo mortality rate after 72 h). The above results show that micro-electrolysis is a potential approach to remove nicotine from solution.
Facile modification of graphite sheet by novel electrochemical exfoliation/oxidant method and its adsorption of caffeine from water
(2017-11-01)
Chung, Yu-Ta
;
Wang, Chih-Kai
;
Wang, Kai-Sung
;
Huang, Sin-Yi
;
Chang, Shih-Hsien
Graphite is an abundant natural material, but its specific area and adsorptive ability are low. In this study, a graphite sheet modified by an electrochemical exfoliation/oxidant process (G(SEEO-modified)) was used as an adsorbent to remove caffeine from solution. Experimental results indicate that G(SEEO-modified) effectively adsorbs caffeine and that the adsorptive ability of GSEEo-modified Prepared with KMnO4 is obviously higher than that of G(SEEO-modified) Prepared with H2O2 or S2O82-. The optimal preparation conditions for G(SEEO-modified) were 1.2 M H2SO4, 0.1 M KMno(4), 80 degrees C, and an applied voltage of 4 V. G(SEEO-modified) of 4.0 g L-1 efficiently adsorbed 95% of the caffeine (Co = 50 mg L-1) within 30 min. Langmuir isotherms describe the adsorption behavior well (q(max) = 1000 mg L-1, b = 0.001, R-2 = 0.9912). Additionally, 0.1 M acetone effectively regenerated exhausted G(SEEO-modified), which maintained a high adsorptive ability (81%) after seven cycles of adsorption-regeneration treatment. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Treatment of Reactive Black 5 by combined electrocoagulation-granular activated carbon adsorption-microwave regeneration process
(2010-03-15)
Chang, Shih-Hsien
;
Wang, Kai-Sung
;
Liang, Hsiu-Hao
;
Chen, Hsueh-Yu
;
Li, Heng-Ching
Treatment of an azo dye, Reactive Black 5 (RB5) by combined electrocoagulation-activated carbon adsorption-microwave regeneration process was evaluated. The toxicity was also monitored by the Vibrio fischeri light inhibition test. GAC of 100 g L(-1) sorbed 82% of RB5 (100 mg L(-1)) within 4h. RB5-loaded GAC was not effectively regenerated by microwave irradiation (800W, 30s). Electrocoagulation showed high decolorization of RB5 within 8 min at pH(0) of 7, current density of 277 A m(-2), and NaCl of 1 g L(-1). However, 61% COD residue remained after treatment and toxicity was high (100% light inhibition). GAC of 20g L(-1) effectively removed COD and toxicity of electrocoagulation-treated solution within 4h. Microwave irradiation effectively regenerated intermediate-loaded GAC within 30s at power of 800 W, GAC/water ratio of 20 g L(-1), and pH of 7.8. The adsorption capacity of GAC for COD removal from the electrocoagulation-treated solution did not significantly decrease at the first 7 cycles of adsorption/regeneration. The adsorption capacity of GAC for removal of both A(265) (benzene-related groups) and toxicity slightly decreased after the 6th cycle. (C) 2009 Elsevier B.V. All rights reserved.
Uptake of BDE-209 on zebrafish embryos as affected by SiO2 nanoparticles
(2018-08-01)
Chao, Shu-Ju
;
Huang, C. P.
;
Chen, Pei-Chung
;
Chang, Shih-Hsien
;
Huang, Chihpin
It was hypothesized that interactions between emerging contaminants such as decabromodiphenyl ether (BDE-209) and nanoparticles (NPs) such as nano-SiO2 (nSiO(2)), can affect contaminant transport in the aquatic environment and its ecotoxicity. This study assessed the influence of nSiO(2) on the uptake of BDE-209 by zebrafish embryo. The distribution of BDE-209 and nSiO(2) on the external chorion and the internal embryo mass (i.e., dechorionated embryo) was measured. For single exposure of nSiO(2) to zebrafish embryo, separately, results showed that nSiO(2) accumulation on the chorion surface was higher than that in the dechorionated embryo. The nSiO(2) accumulation on the chorion surface was 129-200 mg-nSiO(2)/gchorion at 48 h post fertilization, hpf, of exposure time, whereas the equilibrium adsorption of nSiO(2) on the dechorionated embryo was ca. 0.42-0.54 mg-nSiO(2)/g-embryo at 6 hpf. Results showed that the formation of nSiO(2)-BDE-209 associates promoted both extracellular and intracellular uptake of BDE-209 by zebrafish embryo, thereby increasing the bioconcentration of BDE-209 on the chorion surface and in embryo. The results also revealed that the accumulation of BDE-209 on the chorion was remarkably greater than that on the dechorionated embryo at 48 hpf. The uptake of BDE-209 was 17.2 +/- 0.45 mg/g-chorion (or 86 ng-BDE-209/chorionated embryo) and 0.37 +/- 0.01 mg/g-embryo (or 18.6 ng-BDE-209/dechorionated embryo), respectively, when co-exposure of zebrafish embryos to BDE-209 and nSiO(2). Results from the SEM and EDS analysis revealed that nSiO(2) already passed through the chorion and adhered to the embryo surface/mass. (C) 2018 Elsevier Ltd. All rights reserved.