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.

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.

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.

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.

유기인계 농약 중독 환자에서 약물의 종류에 따른 임상 양상 및 예후의 차이

이덕희,정진희,정구영,어은경,Lee, Duk-Hee,Jung, Jin-Hee,Jung, Koo-Young,Eo, Eun-Kyung 대한임상독성학회 2007 대한임상독성학회지 Vol.5 No.1

Purpose: Organophosphorus insecticides tend to be regarded as a homogeneous single entity. We aimed to determine whether organophosphate poisoning differs by subgroups in clinical features and severity. Methods: We retrospectively reviewed medical records of all patients with acute organophophorus poisoning from January 1998 to December 2006. We investigated clinical features, Glasgow coma scale (GCS), laboratory findings, QTc intervals, management, and outcomes. Results: A total of 109 patients were included. The dimethoxy group experienced significantly longer times than the diethoxy group for ventilation duration (0.6 day vs. 0.2 day, p=0.006), ICU duration (2.0 day vs. 0.8 day, p=0.037), and total admission duration (2.8 day vs. 0.9 day, p=0.008), except in cases of dichlorvos poisoning. Also, the GCS of the dimethoxy group (except with dichlorvos) was significantly lower than for the diethoxy group (dimethoxy, $11.2{\pm}5.2$ vs. diethoxy, $13.8{\pm}2.4$, p= 0.021). QTc intervals for the dimethoxy group (except with dichlorvos) tended to be somewhat greater than for the diethoxy group (dimethoxy, $452.9{\pm}16.1\;msec$ vs. diethoxy, $429.6{\pm}40.9\;msec$). There were 65 patients with dichlorvos ingestion, and 2 of these patients (3%) died. Conclusion: When compared to the diethoxy group, the dimethoxy group of organophosphates (with the exception of dichlorvos) were associated with poorer prognostic value for indicators such as GCS, QTc interval, requirement for intubation, ICU duration, and total admission duration. Within the dimethoxy group, patients with dichlorvos poisoning had relatively better prognoses than for the other dimethoxy group organophosphates studied.

제언 - 현대의학의 잃어버린 고리: 저농도 화학물질 혼합체에 대한 만성노출

이덕희,Lee, Deok-Hui 대한산업보건협회 2020 산업보건 Vol.388 No.-

건설현장의 안전관리 개선사항이 근로자의 안전보건 증진에 미치는 영향에 관한 연구

이덕희,박종용,염희상,Lee, Duck Hee,Park, Jong Young,Youm, Hie Sang 한국재난정보학회 2021 한국재난정보학회 논문집 Vol.17 No.3

Purpose: TThis study seeks to understand the provisions of the Industrial Safety and Health Act and the Construction Technology Promotion Act and to propose measures to prevent serious industrial accidents by seeking to promote safety and health of workers through improvement of safety management at construction sites. Method: A survey was conducted on construction sites with more than 50 permanent workers (5 billion won in construction amount). The analysis of the data was conducted using the JAMOVI statistics program and based on objective data. Result: Multiple regression analysis was conducted to verify the hypothesis of this study, and the results of the analysis. The participation of workers in safety and health activities has the highest impact on the promotion of safety and health of workers. Conclusion: In order to promote safety and health of workers at construction sites, compliance with safety and health rules of workers is required and improvements should be made to allow workers to participate in safety and health activities. 연구목적: 본 연구는 산업안전보건법과 건설기술진흥법의 규정을 파악하고, 건설현장의 안전관리 개선을 통하여 근로자의 안전보건 증진방안 모색하여 중대산업재해 방지 방안을 제안하고자 한다. 연구방법: 본 연구의 표본 대상 범위는 상시 근로자 50인(공사금액 50억원) 이상의 건설현장을 대상으로 설문조사를 실시하였다. 자료의 분석은 JAMOVI 통계 프로그램을 이용하였으며, 객관적인 자료를 바탕으로 하여 분석하는 연구를 진행하였다. 연구결과: 본연구의 가설을 검증하기 위하여 다중회귀분석을 시행하였으며, 분석결과. 근로자의 안전보건 활동 참여가 근로자 안전보건 증진에 가장 높은 영향을 미치는 것으로 나타났다. 결론: 건설현장의 근로자 안전보건 증진을 위하여 근로자의 안전보건 규칙 준수가 필요하고 근로자가 안전보건 활동에 참여하도록 개선되어야 한다고 할 수 있을 것이다.

급성기 허혈성 뇌경색의 자기공명영상

이덕희,이정현,Lee, Deok-Hui,Lee, Jeong-Hyeon 대한영상의학회 2004 대한영상의학회지 Vol.50 No.1

최근 뇌혈관 질환 특히 허혈성 뇌졸중에 대한 관심이 고조되고 있고, 확산강조영상의 성공적인 임상 적용은 방사선과, 신경과 의사들의 진단과 치료 패턴에 큰 변화를 몰고 온 계기가 되었다. 이러한 뇌질환에 대한 관심은 국내외적인 상황이라 우리 방사선과 의사들의 적극적인 관심이 요구되는 때라고 생각된다. 이를 계기로 급성 허혈성 뇌경색 특히 증상 발현 6시간 이내의 초급성기 환자의 진단과 치료에 있어서 MR의 역할을 살펴보고자 한다.

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.

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.