LED 폐자원의 재활용 현황

이덕희,신동윤,김태형,이찬기,박경수,이기웅,이재령,Lee, Duk-Hee,Shin, Dongyoon,Kim, Tae-Hyung,Lee, Chan-Gi,Park, Kyung-Soo,Lee, Ki Woong,Lee, Jaeryeong 한국자원리싸이클링학회 2019 資源 리싸이클링 Vol.28 No.2

Development of technology makes LED an economical option because of lower energy consumption and better environmental impact. Because higher consumer demand the LED market is expanding rapidly due to its environment-friendly advantages. Expansion of LED application, development of various fusion technologies, the emergence of new markets, and the large-scale expansion of markets would lead to a large volume of e-waste generation with valorization potential. Currently, most of the generated waste being that landfilled and incinerated due to the absence of technology and management system. In this paper, we review the current status of LED waste recycling and analyzes the available recycling technologies.

정상 소아들의 혈중 연 농도와 지능지수와의 관련성

이덕희,이용환,김진하,박인근,한태영,장세한,Lee, Duk-Hee,Lee, Yong-Hwan,Kim, Jin-Ha,Park, In-Geun,Han, Tae-Young,Jang, She-Han 대한예방의학회 1995 Journal of Preventive Medicine and Public Health Vol.28 No.2

The association between blood lead of children and Intelligent Quotient(I.Q) was investigated in a sample of 100 boys and girls aged $6\sim8$ years from one primary school within an industrial area of Pusan. The trained undergraduates in school of public health administered an 1.0. test one by one. Parents answered a questionnaire on demographic, perinatal and socioeconomic variables. Atomic Absorbtion Spectrophotometer was used to determine blood lead levels. The geometric mean of blood lead value was $7.99{\mu}g/dl$. In total children, there was no significant relationship between blood lead level and I.Q. But in the children who were born of gestational age of less than 38 weeks, children with higher levels of blood lead performed more poorly on I.Q test with correlation coefficient from -0.68 to -0.71. But, the children who were born of gestational age of 38 weeks and more were same as total children. These results suggest that exposure to low levels of lead in the children who were born premature probably may result in impaired intelligent development. But, We think that more profound study should be performed with sufficient numbers of subjects.

One-pot 습식화학공정을 이용한 TiO₂ 중공 구조체 제조 및 광촉매 활성 연구

이덕희,박경수,박재량,이찬기,Lee, Duk-Hee,Park, Kyung-Soo,Park, Jae-Ryang,Lee, Chan-Gi 한국분말야금학회 2020 한국분말재료학회지 (KPMI) Vol.27 No.2

A facile one-pot wet chemical process to prepare pure anatase TiO₂ hollow structures using ammonium hexafluorotitanate as a precursor is developed. By defining the formic acid ratio, we fabricate TiO₂ hollow structures containing fluorine on the surface. The TiO₂ hollow sphere is composed of an anatase phase containing fluorine by various analytical techniques. A possible formation mechanism for the obtained hollow samples by self-transformation and Ostwald ripening is proposed. The TiO₂ hollow structures containing fluorine exhibits 1.2 - 2.7 times higher performance than their counterparts in photocatalytic activity. The enhanced photocatalytic activity of the TiO₂ hollow structures is attributed to the combined effects of high crystallinity, specific surface area (62 ㎡g^-1), and the advantage of surface fluorine ions (at 8%) having strong electron-withdrawing ability of the surface ≡ Ti-F groups reduces the recombination of photogenerated electrons and holes.

APACHE III 시스템을 이용한 병원간 중환자실 치료결과 비교분석

이덕희,노미영,김병성,Lee, Duk-Hee,No, Mee-Young,Kim, Byung-Sung 대한예방의학회 1994 Journal of Preventive Medicine and Public Health Vol.27 No.3

The objective of this study was to evaluate outcome for the patients of the intensive care unit, using APACHE III prognostic system. We prospectively collected the information of 429 patients in intensive care units at 2 tertiary care hospitals and 4 secondary care hospitals in PUSAN who had been admitted from December 1, 1993 to February 28, 1994. The results were as follows. 1. APACHE III scores were various from 0 to 173. But the distribution of the scores were similar between tertiary care hospitals and secondary care hospitals. 2. The mortality rate significantly increased as APACHE III score rised (p<0.001). Within the interval of same score, generally, the mortality of operative patients was higher in secondary care hospitals but in the case of nonoperative patients higher in tertiary care hospitals. 3. When the tertiary care hospitals compared with secondary for ratio of the predicted mortality rate to the actual mortality rate, there was little difference. 4. When we compared the 6 hospitals, one hospital had significantly better results and another hospital was significantly inferior (p<0.05).

다종슬래그를 재활용한 Glass-Ceramic의 제조 및 물성

이덕희,신동윤,윤미정,박현서,윤진호,Lee, Duk-Hee,Shin, Dongyoon,Yoon, Mijung,Park, Hyun Seo,Yoon, Jin-Ho 한국재료학회 2016 한국재료학회지 Vol.26 No.5

Glass-ceramics were developed many years ago and have been applied in many fields such as electronics, chemistry, optics, etc. Much is already known about glass-ceramic technology, but many challenges in glass-ceramic research are still unresolved. Recently, large amounts of slag have steadily increased in the steel industry as by-products. To promote recycling of industrial waste, including steel industry slags, many studies have been performed on the fabrication of basalt-based high-strength glass-ceramics. In this study, we have fabricated such ceramics using various slags to replace high performance cast-basalt, which is currently imported. Glass-ceramic material was prepared in similar chemical compositions with commercial cast-basalt through a pyro process using slags and power plant by-product (Fe-Ni slag, converter slag, dephosphorization slag, Fly ash). The properties of the glass-ceramic material were characterized using DTA, XRD, and FE-SEM; measurements of compressive strength, Vicker's hardness, and abrasion were carefully performed. It is found that the prepared glass-ceramic material showed better performance than that of commercial cast-basalt.

릴레이 기반의 해양 통신 시스템에서 기회주의적 서브채널 할당 기법

이덕희,이성로,소재우,Lee, Deokhui,Lee, Seong Ro,So, Jaewoo 한국통신학회 2014 韓國通信學會論文誌 Vol.39 No.7(통신이론)

본 논문에서는 릴레이 기반의 선박 통신 네트워크에서 데이터 전송률을 높이기 위한 기회주의적 서브채널 할당기법을 제안한다. 릴레이 시스템을 기반으로 하는 기존 연구에서, 릴레이는 매 프레임마다 기지국으로부터 수신 받은 데이터를 선박에게 즉시 전달 해준다. 이때, 이중 홉 네트워크(기지국과 릴레이, 릴레이와 선박 간 링크)에서 전송 가능한 최대 수율은 두 링크의 채널 상태에 의해 결정된다. 만약, 채널 상태에 따른 두 링크가 가지는 채널 용량의 차이가 크다면 자원이 낭비되는 상황이 발생하게 된다. 이러한 문제점은 시스템의 성능을 저하시키며, 제한된 무선 자원을 효율적으로 활용하지 못하는 문제점이 발생하게 된다. 따라서 본 논문에서는 두 링크 사이에서 발생하는 자원의 낭비를 최소화 시킴과 동시에 자원을 효율적으로 할당 할 수 있는 기법을 제안한다. 또한 제안하는 기법의 계산 복잡도를 줄이기 위해서 차선의 기법을 제안한다. 시뮬레이션 결과를 통해서, 제안하는 기법은 기존 연구 대비 계산의 복잡도는 증가하지만 시스템의 데이터 전송률 성능이 최대 14.0% 향상됨을 확인 할 수 있다. This paper proposes an opportunistic subchannel allocation (OSA) scheme for relay-based marine communication networks to improve a sum-rate capacity. In most previous works for relay-based networks, each RS delivers the data received from the BS immediately to the corresponding ships in each frame. The achievable data-rate of the two-hop transmission (BS-RS and RS-ship links) is thus limited by the channel quality between BS-RS and RS-ship links. Hence, the radio resources can be wasted according to the difference in the channel quality between the BS-RS link and the RS-ship link. The proposed OSA scheme reduces the waste of radio resources by efficiently and independently allocating the radio resources at the BS-RS link and at the RS-ship link according to the channel quality of each link. The proposed OSA scheme, however, increases the computational complexity, because the BS finds the optimal OFDMA resource by checking the channel quality of all BS-RS links and RS-ship links. The simulation results show that the sum-rate capacity of the proposed OSA scheme improves maximum 14.0% compared with the conventional scheme.

복합유기용제의 누적 폭로 정도에 따른 신경행동학적 변화

이덕희,박인근,김진하,이용환,강성규,김두희,Lee, Duk-Hee,Park, In-Geun,Kim, Jin-Ha,Lee, Young-Hawn,Kang, Sung-Gye,Kim, Doo-Hie 대한예방의학회 1995 Journal of Preventive Medicine and Public Health Vol.28 No.2

A cross sectional study was performed to evaluate the neurobehavioral effects of chronic exposure of complex organic solvents, using NCTB(Neurobehavioral Core Test Battery) recommended by WHO(World Health Organization). Forty female shoe factory workers and twenty-two controls matched with age were participated. The tests were performed in the morning before start of work, to exclude the effects of acute exposure. Workers were exposed mainly to toluene, methyl ethyl ketone, n-hexane, cyclo-hexane, dichloroethylene, trichloroethylene, benzene, xylenes etc. The ranges of present solvent exposure of hygienic effect were $0.46\sim0.71$ in the process using adhesives indirectly, and $1.83\sim2.39$ in the process using it directly. We reclassified the subjects, according to cumulative exposure. It showed significantly poorer performances in high exposed group on Santa Ana Dexterity and Benton Visual Retention, compared with control group. After controlling confounder, the significances were still remained. But, further cohort studies, having the information of personal exposure dose from entering a factory, are required to clarify the effects of chronic exposure of complex organic solvents in relation to dose and duration of exposure.

TiO₂ 분말 합성을 위한 Ammonium Hexafluofide Titanate의 열적 거동 연구

이덕희,박재량,이찬기,박경수,김현모,Lee, Duk-Hee,Park, Jae-Ryang,Lee, Chan-Gi,Park, Kyung-Soo,Kim, Hyeon-Mo 한국분말야금학회 2016 한국분말재료학회지 (KPMI) Vol.23 No.5

In this study, $TiO_2$ powders are synthesized from ammonium hexafluoride titanate (AHFT, $(NH_4)_2TiF_6$) as a precursor by heat treatment. First, we evaluate the physical properties of AHFT using X-ray diffraction (XRD), particle size analysis (PSA), thermogravimetric analysis (TGA), and field-emission scanning electron microscopy (FE-SEM). Then, to prepare the $TiO_2$ powders, is heat-treated at $300-1300^{\circ}C$ for 1 h. The ratio of anatase to rutile phase in $TiO_2$ is estimated by XRD. The anatase phase forms at $500^{\circ}C$ and phase transformation to the rutile phase occurs at $1200^{\circ}C$. Increase in the particle size is observed upon increasing the reaction temperature, and the phase ratio of the rutile phase is determined from a comparison with the calculated XRD data. Thus, we show that anatase and rutile $TiO_2$ powders could be synthesized using AHFT as a raw material, and the obtained data are utilized for developing a new process for producing high-quality $TiO_2$ powder.

LED 폐자원 재활용: 현황과 향후 방향

이덕희,오현경,박경수,Duk-Hee Lee,Hyeon-Kyung Oh,Kyung-Soo Park 한국자원리싸이클링학회 2024 資源 리싸이클링 Vol.33 No.1

Owing to technological advancements and energy-saving policies, the demand for LED is increasing, leading to rapid industry expansion. Consequently, efficient recycling of accumulated LED waste has become a growing social concern, and current recycling status of LED waste resources and future directions were reviewed. Currently, waste LED recycling is focused on Ga recovery. Therefore, the development of integrated recycling technologies such as pre-treatment and concentration/recovery of high valued materials is necessary. In this study, we investigated the status and recycling technologies of waste LED and presented prospects.

유기금속화학증착 분진(MOCVD dust)을 이용한 갈륨 함유 고순도 수용액 제조 연구

이덕희,윤진호,박경수,홍명환,이찬기,박정진,Lee, Duk-Hee,Yoon, Jin-Ho,Park, Kyung-Soo,Hong, Myung-Hwan,Lee, Chan-Gi,Park, Jeung-Jin 한국자원리싸이클링학회 2015 資源 리싸이클링 Vol.24 No.4

본 연구에서는 LED 칩 제조를 위해 이용되는 유기금속화학증착(MOCVD) 장비에서 발생하는 분진(dust)으로부터 용매추출을 통해 고순도 갈륨(Ga) 함유 수용액을 회수하는 연구를 수행하였다. 추출제 종류, 추출제의 농도 변화에 대한 연구를 통해 Ga 추출에 효과적인 추출제를 선정하고자 하였으며 다단계 추출/역추출 공정을 통해 추출 효율을 향상시켜 고순도 Ga 수용액을 제조하였다. 선행연구에서 원료에 대한 분석을 바탕으로 Ga의 추출 및 분리를 위해 PC88A, DP-8R, Cyanex 272 추출제 중 Cyanex 272를 선택하였으며 1.5M일 때 43.8%의 효율이 나타났다. 다단계 추출을 통해 Ga의 추출 효율은 83%까지 상승하였으며 0.1 M HCl을 이용한 역추출 공정으로 불순물이 없는 5N급 고순도 Ga 수용액을 제조할 수 있었다. In this study, we have investigated solvent extraction of Ga and recovery of high pure Ga solution from MOCVD dust for manufacturing of LED chip. Effect of extractan, concentration of extractant were examined for choosing the more effective extractant and high pure Ga solution was fabricated by multi-stage extraction/stripping process. For extraction/separation of Ga based on the analysis of raw-material in previous study, 3 different extractants PC 99A, DP-8R, Cyanex 272 has been investigated and the extraction efficiency of 1.5 M Cyanex 272 was 43.8%. It was conformed that extraction efficiency of Ga was 83% in multi-stage extraction and 5N high purity Ga stripping solution without impurities also obtained.