Recovery of Gallium and Indium from Waste Light Emitting Diodes

Chen, Wei-Sheng,Chung, Yi-Fan,Tien, Ko-Wei The Korean Institute of Resources Recycling 2020 資源 리싸이클링 Vol.29 No.1

Recovery of gallium and indium from waste light emitting diodes has been emphasized gradually owing to high content of gallium and indium. This study was established the recovery of gallium (Ga³⁺) and indium (In³⁺) from waste gallium nitride was contained in waste light-emitting diodes. The procedure was divided into the following steps; characteristic analysis, alkaline roasting, and leaching. In characteristic analysis part, the results were used as a theoretical basis for the acid leaching part, and the chemical composition of waste light emitting diodes is 70.32% Ga, 5.31% Si, 2.27% Al and 2.07% In. Secondly, with reduction of non-metallic components by alkaline roasting, gallium nitride was reacted into sodium gallium oxide, in this section, the optimal condition of alkaline roasting is that the furnace was soaked at 900℃ for 3 hours with mixing Na₂CO₃. Next, leaching of waste light emitting diodes was extremely important in the process of recovery of gallium and indium. The result of leaching efficiency was investigated on the optimal condition accounting for the acid agent, concentration of acid, the ratio of liquid and solid, and reaction time. The optimal condition of leaching procedures was carried out for 2.0M of HCl liquid-solid mass ratio of 30 ml/g in 32minutes at 25℃ and about 96.88% Ga and 96.61% In were leached.

The Effect of CdS QDs Structure on the InGaP/GaAs/Ge Triple Junction Solar Cell Efficiency

Chen-Chen Chung,Binh Tinh Tran,Hau-Vei Han,Yen-Teng Ho,Hung-Wei Yu,Kung-Liang Lin,Hong-Quan Nguyen,Peichen Yu,Hao-Chung Kuo,Edward Yi Chang 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.2

This work describes optical and electrical characteristics of InGaP/GaAs/Ge triple-junction (T-J) solar cells with CdS quantum dots (QDs) fabricated by a novel chemical solution. With the anti-reflective feature at long wavelength and down-conversion at UV regime, the CdS quantum dot effectively enhance the overall power conversion efficiency more than that of a traditional GaAs-based device. Experimental results indicate that CdS quantum dot can enhance the short-circuit current by 0.33 mA/cm2, which is observed for the triple-junction solar cells with CdS QDs of about 3.5 nm in diameter. Moreover, the solar cell conversion efficiency is improved from 28.3% to 29.0% under one-sun AM 1.5 global illumination I-V measurement.

TLPKA: Pairwise Key Agreement Based on the Geometrical Property of the Tangent Line in Ad Hoc Network Systems

Chung-Wei Chen,Shiuh-Jeng Wang,Yuh-Ren Tsai 보안공학연구지원센터 2008 International Journal of Hybrid Information Techno Vol.1 No.4

In this paper, we propose a new pairwise key agreement, TLPKA (Tangent Line Pairwise Key Agreement), for establishing a secure link between members in an ad hoc network. With pairwise keys, data transmitted in ad hoc networks can be protected from the eavesdropping of outsiders. These pairwise keys can also be used to authenticate members in ad hoc networks. In addition, due to the property of uniqueness of pairwise keys, it also provides non-repudiation for data transmitting. In our scheme, we propose a new idea for the design of pairwise key agreements in an ad hoc network. Our scheme is based on the geometrical property of the tangent line and the mechanisms in our scheme are inspired by the Shamir secret sharing scheme. Our schemes also provide reciprocal authentication among node communicants. The robustness of our scheme is based on the DH problem and the indefinite solutions in coordinate geometry. In addition, we compare our scheme with other schemes. Although there is a higher overhead associated with our scheme, it maintains a higher security level than the other schemes.

Effect of the Circle-Grid Electrodes on Concentrated GaAs Solar Cell Efficiency

Chen-Chen Chung,Binh Tinh Tran,Ming-Hung Han,Kung-Liang Lin,Hung-Wei Yu,Yen-Teng Ho,Chun-Yen Chang,Edward Yi Chang 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.5

In this study, we investigate the effect of the shading factor of the front grid pattern on concentrated solar cell efficiency, taking the trade-off between the series resistance of the electrodes and the amount of incident light into consideration. We examine the thermal effect with regard to five different circle-grid electrode patterns of the front contact. The front contacts with different grid patterns affect the characteristics of light-concentratedtype GaAs single-junction solar cells. The device parameters analyzed include the open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF) and conversion efficiency (η). The results of our study show that for a concentration ratio greater than 60x with AM1.5G, the device with a shading factor of 7.1% has the best cell efficiency of 27.05%, due to the smaller current crowding at the center spot. The results indicate that the conversion efficiency of solar cells can be improved by establishing a compromise between the shading effect and the series resistance effect.

Common Mode Voltage Reduction in Four-Leg Inverter with Multicarrier PWM Scheme

Chung-Chuan Hou,Po-Wei Wang,Ching-Chen Chen,Chen-Wei Chang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Three-phase three-leg inverter has an inherent common mode voltage (CMV) problem. Therefore, threephase four-leg inverter is presented to mitigate the CMV of the inverter. This study discusses the characteristics of multicarrier pulse width modulation (PWM) for threephase four-leg inverter. The multicarrier PWM scheme is utilized to reduce the CMV of the inverter. The analysis of sinusoidal PWM and space vector PWM with multicarrier is discussed. The experimental results are utilized to validate the performances of the proposed multicarrier PWM scheme.

Overexpression of Ornithine Decarboxylase Suppresses Thapsigargin-Induced Apoptosis

Wei-Chung Hsieh,Pei-Chen Hsu,Ya-Fan Liao,Shu-Ting Young,Zeng-Wei Wang,Chih-Li Lin,Gregory J. Tsay,Huei Lee,Hui-Chih Hung,Guang-Yaw Liu 한국분자세포생물학회 2010 Molecules and cells Vol.30 No.4

Ornithine decarboxylase (ODC), the key enzyme of poly-amine biosynthesis, has paradoxical roles in apoptosis. Our published papers show overexpression of ODC pre-vents the apoptosis induced by many cytotoxic drugs. Thapsigargin (TG) is an inhibitor of the sarcoplasmic/en-doplasmic reticulum (ER) Ca2+ ATPase (SERCA) pumps and causes ER stress-induced apoptosis. We used ODC overexpressing cell lines to examine whether overexpres-sion of ODC inhibits TG-induced apoptosis. Our results indicated overexpression of ODC attenuated TG-induced apoptosis. Overexpression of ODC blocked procaspse-4 cleavage and phosphorylation of protein kinase-like ER-resident kinase (PERK), triggered by TG. It also attenuated the increase in CAAT/enhancer binding protein homolo-gous protein (CHOP). Cells with overexpressed ODC had greater Bcl-2 expression. Overexpression of ODC pre-served the expression of Bcl-2, inhibited the increase in Bak and stabilized mitochondrial membrane potential without the influences of TG. Cytochrome c release and downstream caspase activation were blocked. That is, overexpression of ODC inhibits the mitochondria-medi-ated apoptotic pathway, induced by TG. Finally, overex-pression of ODC maintains the protein and mRNA expres-sion of SERCA. In conclusion, overexpression of ODC suppresses TG-induced apoptosis by blocking caspase-4 activation and PERK phosphorylation, attenuating CHOP expression and inhibiting the mitochondria-mediated apoptotic pathway.

Overexpression of Ornithine Decarboxylase Suppresses Thapsigargin-Induced Apoptosis

Hsieh, Wei-Chung,Hsu, Pei-Chen,Liao, Ya-Fan,Young, Shu-Ting,Wang, Zeng-Wei,Lin, Chih-Li,Tsay, Gregory J.,Lee, Huei,Hung, Hui-Chih,Liu, Guang-Yaw Korean Society for Molecular and Cellular Biology 2010 Molecules and cells Vol.30 No.4

Ornithine decarboxylase (ODC), the key enzyme of polyamine biosynthesis, has paradoxical roles in apoptosis. Our published papers show overexpression of ODC prevents the apoptosis induced by many cytotoxic drugs. Thapsigargin (TG) is an inhibitor of the sarcoplasmic/endoplasmic reticulum (ER) $Ca^{2+}$ ATPase (SERCA) pumps and causes ER stress-induced apoptosis. We used ODC overexpressing cell lines to examine whether overexpression of ODC inhibits TG-induced apoptosis. Our results indicated overexpression of ODC attenuated TG-induced apoptosis. Overexpression of ODC blocked procaspse-4 cleavage and phosphorylation of protein kinase-like ER-resident kinase (PERK), triggered by TG. It also attenuated the increase in CAAT/enhancer binding protein homologous protein (CHOP). Cells with overexpressed ODC had greater Bcl-2 expression. Overexpression of ODC preserved the expression of Bcl-2, inhibited the increase in Bak and stabilized mitochondrial membrane potential without the influences of TG. Cytochrome c release and downstream caspase activation were blocked. That is, overexpression of ODC inhibits the mitochondria-mediated apoptotic pathway, induced by TG. Finally, overexpression of ODC maintains the protein and mRNA expression of SERCA. In conclusion, overexpression of ODC suppresses TG-induced apoptosis by blocking caspase-4 activation and PERK phosphorylation, attenuating CHOP expression and inhibiting the mitochondria-mediated apoptotic pathway.

Seasonal yeast compositions in Forcipomyia taiwana (Diptera: Ceratopogonidae)

Hung-Wei Chen,Jui-Yu Chou,Chung-Chi Lin,Yu-Der Wen,Wei-Lung Wang 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.2

Forcipomyia taiwana, a biting midge, is one of the most annoying blood-sucking pests in Taiwan. The larvae of Forcipomyia species feed primarily on algae, and the adults feed on nectar for nutrition. After mating with male adults, females bite humans and digest blood for the formation and development of their eggs. The bites often cause human itching, swelling, skin lesion and even fatal shock. Harassment from this biting pest has become a serious problem and has influenced the quality of outdoor recreational activities. Thus, it is necessary to understand the ecology of F. taiwana to develop an effective control strategy. This study showed the seasonal variation of yeast compositions in the interior of F. taiwana. Furthermore, we found that Aureobasidium spp. appeared the most during collection times and these yeasts are able to decompose the cellulose, a major component in the cell wall of algae and Oomycete fungi. These fungi infect a broad range of host and have adverse effect on fitness of the biting midges. Thus, Aureobasidium spp. play a crucial role in the defense system of F. taiwana against pathogens. The study provides useful information that could be used in the development of biocontrol strategy in the future.

Age and Sex Distribution of Chinese Chronic Cough Patients and Their Relationship With Capsaicin Cough Sensitivity

Kefang Lai,Li Long,Fang Yi,Jiaman Tang,Zhe Chen,Fagui Chen,Jianmeng Zhou,Wen Peng,Liting Zhang,Hu Li,Wenzhi Zhan,Ruchong Chen,Wei Luo,Qiaoli Chen,Kian Fan Chung,Nanshan Zhong 대한천식알레르기학회 2019 Allergy, Asthma & Immunology Research Vol.11 No.6

Purpose: An older female predominance has been reported among chronic cough patients in Western countries, which is considered to be associated with a higher cough sensitivity in females. However, the characteristics of Chinese chronic cough patients remain unclear. This study aimed to explore the age and sex distribution as well as their relationship with cough reflex sensitivity to capsaicin in Chinese chronic cough patients. Methods: We analyzed the demographic features of 1,882 consecutive chronic cough patients who attended our cough clinic in Guangzhou, China. Cough sensitivity to capsaicin, which was defined as the lowest concentration of capsaicin causing 5 coughs or more (C5), was measured in 539 of the 1,882 patients and 68 healthy volunteers. Results: The mean age of the patients was 43.0 ± 13.7 years and patients aged <50 years accounted for more than two-thirds of the study population. Around 87% of the patients were never-smokers. The proportion of females (51.5%) was almost equal to that of males (48.5%). The pattern of the age and sex distribution was consistently reflected within most common causes of chronic cough, while a female predominance was shown in patients with coughvariant asthma and patients aged ≥50 years. Female patients had higher cough sensitivity to capsaicin than male patients (log C5: 1.58 ± 0.84 vs. 2.04 ± 0.84 μmol/L, P = 0.001), and patients aged ≥50 years had higher cough sensitivity to capsaicin than patients aged <50 years. Conclusions: In China, patients with chronic cough have a roughly equal sex distribution and a middle-aged predominance, irrespective of a higher cough sensitivity to capsaicin in females and older patients.

Effect of Light Intensity on Growth and Development of Grafted Watermelon Seedlings during Wound Healing Period

Chung Ho Ko,Hao Wei,Yuze Chen,Byoung Ryong Jeong 한국원예학회 2014 한국원예학회 학술발표요지 Vol.2014 No.10