Light-extraction efficiency control in AlGaN-based deep-ultraviolet flip-chip light-emitting diodes: a comparison to InGaN-based visible flip-chip light-emitting diodes.

Lee, Keon Hwa,Park, Hyun Jung,Kim, Seung Hwan,Asadirad, Mojtaba,Moon, Yong-Tae,Kwak, Joon Seop,Ryou, Jae-Hyun Optical Society of America 2015 Optics express Vol.23 No.16

<P>We study light-extraction efficiency (LEE) of AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs) using flip-chip (FC) devices with varied thickness in remaining sapphire substrate by experimental output power measurement and computational methods using 3-dimensional finite-difference time-domain (3D-FDTD) and Monte Carlo ray-tracing simulations. Light-output power of DUV-FCLEDs compared at a current of 20 mA increases with thicker sapphire, showing higher LEE for an LED with 250-관m-thick sapphire by ~39% than that with 100-관m-thick sapphire. In contrast, LEEs of visible FCLEDs show only marginal improvement with increasing sapphire thickness, that is, ~6% improvement for an LED with 250-관m-thick sapphire. 3D-FDTD simulation reveals a mechanism of enhanced light extraction with various sidewall roughness and thickness in sapphire substrates. Ray tracing simulation examines the light propagation behavior of DUV-FCLED structures. The enhanced output power and higher LEE strongly depends on the sidewall roughness of the sapphire substrate rather than thickness itself. The thickness starts playing a role only when the sapphire sidewalls become rough. The roughened surface of sapphire sidewall during chip-separation process is critical for TM-polarized photons from AlGaN quantum wells to escape in lateral directions before they are absorbed by p-GaN and Au-metal. Furthermore, the ray tracing results show a reasonably good agreement with the experimental result of the LEE.</P>

업종에 따른 연 취급 사업장의 기중 연 농도 및 연 노출 수준 평가

이병국,김용배,리갑수,안현철,김화성,이용진,황규윤,장봉기,이성수,안규동 순천향대학교 산업의학연구소 1999 순천향산업의학 Vol.5 No.1

In order to obtain an useful information for health management and biological monitoring of lead exposed workers, Authors tried to investigate air lead level and the lead exposed level of workers in lead industry according to occupational category. The subjects in our study were 2074 workers in 7 lead-using industries, and study subjects were divided into 4 occupational categories such as storage battery industry (type 1), primary smelting industry (type 2), secondary smelting industry (type 3) and litharge making industry (type 4). Blood zincprotoporphyrin concentration (ZPP), blood lead concentration (PbB) and urinary δ -aminolevulinic acid (ALAU), hemoglobin (Hb), hematocrit (Hct) were selected as the indices of lead exposure. Personal variables such as age, work duration were also collected. The results were as follows. 1. The geometric mean air lead in 9 lead-using industry was 0.1133±4.3120 ㎎/㎥, and that in type 1, 2, 3 and 4 was 0.1038±3.4952 ㎎/㎥, 0.0429±3.4329 ㎎/㎥, 0.1877±2.5123 ㎎/㎥ and 0.9961±5.2910 ㎎/㎥, respectively. 2. The mean ZPP in 9 lead-using industry was 53.1±28.0 ㎍/㎗, and that in type 1, 2, 3 and 4 was 52.0±24.8 ㎍/㎗, 48.0±16.4 ㎍/㎗, 109.8±85.6 ㎍/㎗ and 74.3±37.8 ㎍/㎗, respectively. There was significant difference in ZPP according to occupational category (P<0.01). The percents of lead workers whose ZPP were above 100 ㎍/㎗ in type 1, 2, 3 and 4 were 4.0%, 1.7%, 34.3% and 21.6%, respectively. 3. The mean PbB in lead-using industry was 26.0±11.2 ㎍/㎗, and that in type 1, 2, 3 and 4 was 25.3±11.1 ㎍/㎗, 26.7±8.8 ㎍/㎗, 50.3±15.2 ㎍/㎗ and 36.4±11.0 ㎍/㎗, respectively. There was significant difference in PbB according to occupational category (P<0.01). The percents of lead workers whose PbB were above 40 ㎍/㎗ in type 1, 2, 3 and 4 were 10.4%, 7.7% 71.9% and 43.2%, respectively. 4. While the correlation of Hb corrected PbB with ZPP was higher than non corrected PbB, the correlation of log-transformed ZPP with PbB was higher than non corrected ZPP. 5. Simple linear regressions of PbB and corrected PbB as independent variable with ZPP, log-transformed ZPP and ALAU as dependent variable were statistically significant (P0.01). Coefficient of determination of corrected PbB with other variables was higher than non corrected PbB. As the result of this study, it was suggested that reconsideration of environmental and biological monitoring program was highly recommended for secondary smelting and litharge making industry.

최신토지피복자료를 이용한 대구시의 열환경 수치모의

이현주(Hyun-Ju Lee),이귀옥(Kwi Ok Lee1),원경미(Gyeong Mee Won),이화운(Hwa Woon Lee) 한국대기환경학회 2009 한국대기환경학회지 Vol.25 No.3

Plant regeneration from callus of Iris odaesanensis Y. N. Lee native to Korea via organogenesis

Bae, Kee-Hwa,Yoo, Kyoung-Hwa,Lee, Mi-Hyun,Jeong, Jae-Hun,Choi, Yong-Eui,Yoon, Eui-Soo The Korean Society of Plant Biotechnology 2013 식물생명공학회지 Vol.40 No.3

Iris odaesanensis Y. N. Lee. is an important endangered and native plant belonging to the family Iridaceae in Korea. This study describes a method for rapid micropropagation of this species via from leaf, rhizome and root explants derived calli. Leaf, rhizome and root explants were cultured on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) for callus induction. Rhizome explants yielded calli at a frequency of 72% when cultured at 1.0 mg/l 2,4-D. Calli were maintained at 1.0 mg/l 2,4-D. These calli were transferred to MS medium supplemented with 0, 0.5, 1.0, and 2.0 mg/l 2,4-D in combination with 0, 0.5, 1.0, and 3.0 mg/l BA for adventitious shoot induction. The highest number of adventitious shoot (228.9 per petri-dish) were formed at 1.0 mg/l 2,4-D and 1.0 mg/l BA. WPM medium was the best to convert calli into plantlets, where up to 98.2% of calli were regenerated into plantlets. This in vitro propagation protocol should be useful for conservation of this endangered plant.

간호실무에서 신봉이론(Espoused theories)에 대한 탐색적 연구

서문자,김혜숙,이은희,박영숙,조경숙,강현숙,임난영,김주현,이소우,조복희,이명하,지성애,하양숙,손영희,권성복,김희진,추진아 성인간호학회 2001 성인간호학회지 Vol.13 No.1

As a nursing practice involves nurses' actions in a specific context of health care, this study has focused on exploring the espoused theories in nursing practice within the action science perspectives, Espoused theories are the belief, principles, and rationale expressed by the practitioner as guiding her/his actions in a situation of practice. The data were analysed qualitatively and 25 elements of espoused theories of nursing action were identified and clustered into 6 categories. The 25 elements of espoused theories are as follows: The clinical nurse worked in wholistic and individual nursing, focussed on the patient's needed, comfort and supportive nursing (5 theories of nursing goal) ; excellent skills, knowledge based, assessment and data collection, explaining, educating or a scientific basis(6 theories of nursing intervention): advocacy, value oriented, treatment, account- ability and commitment(4 theories of nursing ethics) ; human respect. partnership, trust(3 theories of patient-nurse relationship) : knowledgable, accumulated clinical experiences and personally lived experiences. positive perspectives(4 theories of nurse), role of intervention. rewarding peer relationship(3 theories of situations) The above mentioned espoused theories are similar to that of nursing textbooks which students learned through basic nursing education and almost the same as the Acts ofa Nurse in Korean. However, we are doubtful whether nurses actually do as they think. Therefore. it is recommended to review the theories-in-use in order to and any discrepancies between the espoused theories and the reality of nursing actions

일부 사업장 건강증진사업 실태조사 및 요인분석

이경화,이원철,이강숙,홍현숙,송연이 가톨릭대학교 산업의학센터 2000 韓國의 産業醫學 Vol.39 No.2

For the purpose of access the health promotion activities in 138 worksite which had more than 50 workers, we surveyed the questionnaire on May and September 1998. The results of survey were as follows: 1.59 companies(45.1%) were conducting the health promotion activities. Most of them were manufacturing and located Kyung-sang province and had nurses as a health manager. 2.Companies operating the health promotion activities had significant higher degree of satisfaction and usage of welfare facilities than non-operating companies. 3.The level of knowledge for regulations, professional skills, and performance related health promotion was low in all companies. Top manager's interest and will for investment to health promotion was significant lower in non-operating companies. 4.The reasons why the health promotion program was not operated, were low budget, top manager's indifference, lack of information, work overloading, no human resource, an insufficient governmental support in order. 5.The most necessary items for program were education and promotion, budget, and governmental support. Needed personnel were nurses, fitness trainner, and necessary program were health management, exercise, nutrition, and stress counselling. For comparing before and after IMF, amount of budget was decreased. In conclusion, this study suggested that major barriers to conduct health promotion activities were lack of budget, lower interest of top managers, and insufficient professional information, therefore detail health promotion program would be developed and supported by government.

總括生産計劃에서 適定 퍼지수 比較法의 選擇에 관한 硏究

李相玩,朴永和,南賢祐,尹延根 동아대학교 공과대학 부설 한국자원개발연구소 1992 硏究報告 Vol.16 No.1

When using any of the aggregate production planning techniques mentioned in previous studies, it is generally assumed that the inputs of information are deterministic and easy to generate. However, the problem is more complex if the criteria and informations are expressed imprecisions. Therefore, it requires suitable method to deal with imprecisions. For select proper comparison method of fuzzy numbers in aggregate production planning with imprecise informations or criteria, this study use Dubois & Prade fuzzy number comparison method and Li-Lee fuzzy number comparison method among comparison methods fuzzy numbers. And then, proper method between two methods is selected. Also it is presented illustration.

Paint sludge내 활성을 고려한 건조방법에 관한 연구

이순홍,백우진,윤강재,이재현,김화진 안양대학교 산업기술연구소 2004 自然科學硏究 Vol.11 No.1

각종 도장산업에서 발생하는 paint sludge는 대부분 소각후 매립 또는 건조과정을 거쳐 단순 무기재로서 재활용되어지고 있다. paint sludge의 양은 매년 증가하는 추세이고 이에따라 국내외에서는 paint sludge를 보다 가치가 높은 유기재로서 재활용하는 방안이 연구되어지고 있다. 따라서 재활용공정 중 필수공정인 건조방법을 이전과는 다른 방법등을 도입하여 paint sludge내 활성기를 보존하고 함유수분을 효율적으로 제거하기 위하여 효과적인 연구방법을 찾는데 연구의 목적이 있다. 본 연구에서는 문헌연구를 통하여 건조온도를 낮추는 효과를 기대할 수 있는 물리적 방법인 감압건조법과 paint sludge에 첨가제를 첨가하여 건조효율을 높일 수 있는 화학적 첨가제를 첨가한 방법을 건조방법에 적용하여 실험하였다. 또한 화학적 첨가제 첨가 후 전처리로서 수분산시킨후 감압여과하는 공정을 추가하여 실험하였다. 감압건조법을 이용하여 활성기 잔존을 위한 최적의 조건을 온도별, 압력별 건조효율 비교실험을 통하여 80℃, 60mmHg로 결정한 후 각 첨가제별 건조효율을 비교하였다. 4가지 첨가제 중 bentonite가 24시간 건조 후 함수율 2.38%로 가장 높은 효율을 나타냈었다. 또한 전처리를 행한 경우 magnesium chloride, sodium hydrogen carbonate 및 bentonite는 paint sludge 입자내 수분을 흡습하여 여과시 시간을 길게 진행하여도 기존의 함수율보다 낮은 함수율을 얻었다. Calcium oxide경우 감압여과 30분 처리 후 감압건조를 실시한 결과 첨가량이 증가할수록 높은 효율을 나타내었으며 첨가량 5%일때를 제외하고 10%, 20%, 30%일때 모두 4시간안에 5%이하의 함수율을 얻을 수 있어 감압건조만으로 이루어진 공정에 비해 절반정도의 시간을 단축할 수 있었다. 첨가제량에 따른 경제성과 재활용시 영향을 미칠 가능성을 고려하여 첨가제량은 10%정도가 적절한 것으로 판단된다. Paint sludge내 활성을 고려한 건조방법에 관한 연구 활성기의 손실여부는 FT-IR spectrum을 사용하여 -COOH, -OH 및 -NH_(2)기가 건조후 paint sludge powder내에 존재하고 있음을 확인하였다. 활성기의 존재로 인하여 paint sludge의 물성을 유지한 고기능성 재료로의 재활용이 가능할 것으로 예상되며 실제 공정에 적용할 경우 좀 더 많은 연구가 필요할 것이라 사료된다. Most of the paint sludge that is derived in the paint industry is buried after incineration. Only a few amount of them recycled as an inert inorganic filler in the fine powder form by the process of being dried or after incineration. The purpose of this study is to find out the effective method that can dehydrate and preserve active radical in efficiency. We made the experiment on the method of decompression drying which can lower the temperature of drying as a physical method, the method of a chemical addition which can rise the efficiency of drying. In the study, bentonite was the most excellent in the dehydrating efficiency to show the final water content of 4.5% in 10 hours, and sodium hydrogen carbonate, magnesium chloride, calcium oxide, raw paint sludge followed bentonite in order to of efficiency, when we decided 60mmHg, 80℃ as the best suited condition for the survival of active radical. We measured the loss of active radical by using FT-IR spectrum and confirmed the existence of -COOH, -OH and NH_(2) radicals in paint sludge.

일회통과 관류실험시 물의 수송 : 관류액의 종류와 삼투압의 영향 Effects of Some Perfusates and Their Osmolality

이정화,이현주,용철순,오두만 영남대학교 약품개발연구소 1995 영남대학교 약품개발연구소 연구업적집 Vol.5 No.-

The single pass perfusion experiments were performed in anesthetized rata to investigate the effects of perfusates and their osmolality on the water transport and to determine the correlation between the extent of water transport and the volume change of perfusate. Phenol red was used as a nonabsorbable marker. In normal rats, when perfused at a flow rate of 0.5 ml/min 2-(N-morpholino) ethanesulfonic acid (MES) aid Sorensen's phosphate hullers showed minimal net water transport as 0.125 and 0.173 %/cm of intestinal length, respecetively. Hypotonic perfusate of 200 mOsm㎏ of water and hypertonic perfusate of 400 mOsm/㎏ of water generated significant water transport compared with isotonic perfusate of 300 mOsn/㎏ of water. There was a linear correlation between the attent of water transport and the volume change of perfusate, suggesting that the volume change can be used as a measure of water transport.

peat moss를 이용한 폐수중의 중금속 제거

이경화,김정섭,유현철,최성우,윤철종,우성훈,박승조 동아대학교 환경문제연구소 2001 硏究報告 Vol.24 No.1

Adsorption equilibrium of heavy metals ion on the peat moss was confirmed Frundlich isotherm Removal efficiency of heavy metals ion was increased from pH 2 to 10 and heavy metal removal efficiency was increased in the sequence of Cu(Ⅱ) > Pb(Ⅱ) > Cd(Ⅱ) > Mn(Ⅱ) on the PM(Peat Moss). The PM is likely to be more effective adsorption than the PAC to removal of metal ions in the solution, since PM's weakly acidic functional groups which is not founded on the PAC, in addition to its high surface area and porosity. But, the PM is not separated from the solution water by sedimentation process. So, a liquid and solid seperation between the PM and the solution water could be considered for the PM's field application. But peat moss was low cost adsorbent. Thus author propose to adopt PM as a adsorbent for heavy metal removal.