• Journal of the Microelectronics and Packaging Society
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• v.4 no.2
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• pp.71-78
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• 1997

본 논문에서는 InGaAsP 에피막에서 도핑 농도와 에피막의 미세조직구조가 photoluminescence (PL) 스펙트럼의 위치 및 형상에 어떤 영향을 미치는가를 연구하였고, 그 결과를 설명하기 위해 가능한 모델을 제시하였다. InGaAsP 에피막(발진파장 ~1.3$\mu$m) 을 액상증착법(liquid phase epitaxy, LPE)으로 성장하여 9K에서 PL측정을 했을 때 InGaAsP 활성층 내 Zn 억셉터의 유무에 따라 PL 피크의 위치가 최대 30nm (24meV)까지 shift하고 피크의 선폭도 넓어지는 현사을 발견하였다. 이와같은 피크 분산현상은 inGaAsP 에피막이 유기금속 기상증착법으로 성장되거나 Zn로 고농도로 도핑되거나 고온에서 어닐링 될 경우 대폭 감소하였다. 이를 설명하기 위해 여러 가지 모델을 설정하여 실험을 하였으며 이 중 InGaAsP 에피막의 미세조직구조 특히 Spinodal 분해에 의한 조성이 모듈레이션과 Zn의 상호작용의 관계가 이 현상을 설명하는 데 가장 적절하다는 것을 밝혔다.

• Parasites, Hosts and Diseases
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• v.52 no.6
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• pp.621-629
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• 2014

Malaria is one of the most widespread infectious diseases of tropical countries with an estimated 207 million cases globally. In India, there are endemic pockets of this disease, including Aligarh. Hundreds of Plasmodium falciparum and P. vivax cases with severe pathological conditions are recorded every year in this district. The aim of this study is to find out changes in liver enzymes and kidney markers. Specific diagnosis for P. falciparum and P. vivax was made by microscopic examination of Giemsa stained slides. Clinical symptoms were observed in both of these infections. Liver enzymes, such as AST, ALT, and ALP, and kidney function markers, such as creatinine and urea, were estimated by standard biochemical techniques. In Aligarh district, P. vivax, P. falciparum, and mixed infections were 64%, 34%, and 2%, respectively. In case of P. falciparum infection, the incidences of anemia, splenomegaly, renal failure, jaundice, and neurological sequelae were higher compared to those in P. vivax infection. Recrudescence and relapse rates were 18% and 20% in P. falciparum and P. vivax infections, respectively. Liver dysfunctions and renal failures were more common in P. falciparum patients, particularly in elderly patients. Artesunate derivatives must, therefore, be introduced for the treatment of P. falciparum as they resist to chloroquine as well as sulfadoxine-pyrimethamine combinations.

• Tuberculosis and Respiratory Diseases
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• v.38 no.3
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• pp.262-269
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• 1991

The purpose of this study is to investigate the utility of the pleural fluid cholesterol level in separating the exudates from the transudates, and in differentiating tuberculous exudates from non-tuberculous exudates, 52 patients with pleural effusion were involved in this prospective study. By predefined criteria, 40 of these effusions were classified as exudates (Group I) and 12 as transudates (Group II). Group I was subdivided into tuberculous exudates (Group A) and non-tuberculous exudates (Group B). The followings are parameters used in separating the exudates from the transudates; pleural protein (P-PROT) 3.0 g/dl, pleural protein/serum protein ratio (P/S PORT) 0.5, pleural LDH (P-LDH) 200 IU, pleural LDH/serum LDH ratio (P/S LDH) 0.6, pleural cholesterol (P-CHOL) 50 mg/dl and pleural cholesterol/serum cholesterol ratio (P/S CHOL) 0.4. Mean values of the parameters in each group were compared, and then misclassified rate and the dignostic efficiency for each parameter were calculated. The results were as follows; 1) Mean P-CHOL ($94.98{\pm}73.86\;mg/dl$) in Group I was higher than that ($36.5{\pm}26.5\;mg/dl$) in Group II (p<0.05), but there was no significant difference in mean P-CHOL between Group A and Group B. 2) Mean P/S CHOL ($0.64{\pm}0.39$) in Group I was also higher than that ($0.27{\pm}0.15$) in Group II (p<0.01), but no difference was observed in mean P/S CHOL between Group A and Group B. 3) Misclassified rates for each parameter in separating the exudates from the transudates were as follows; P-PROT 1.9%. P/S PROT 3.8%. P-CHOL 9.6%, P/S CHOL 11.5%, P/S LDH 11.5%, and P-LDH 17.3%. 4) Diagnostic efficiencies for each parameter in separating the exudates from the transudates were as follows; P-PROT 98.1%, P/S PROT 96.2%. P-CHOL 90.4%. P/S CHOL 88.5%, P/S LDH 88.5%, and P-LDH 82.7%. In conclusion, we think that the pleural fluid chloesterol level could be used as a supportive parameter in separating the exudates from the transudates, but could not be used as a parameter in differentiating tuberculous exudates from non-tuberculous exudates.

• Journal of Korean society of Dental Hygiene
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• v.8 no.4
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• pp.165-180
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• 2008

The present study is a descriptive survey on factors affecting middle school students' oral health belief and oral health practice. In order to find methods for forming right beliefs and inducing desirable behavioral patterns, we conducted a questionnaire survey with 470 students at two middle schools in Cheongju and drew conclusions as follows. Of the 470 questionnaires, 457 were recovered. With 10 inappropriately answered ones excluded, 446 questionnaires were analyzed. 1. As to oral health belief according to general characteristics, susceptibility was 2.63 points (p=0.035) in male students, 2.68 (p=0.016) in 3rd year students, and 2.92 (p=0.002) in only child students. Seriousness was 2.57 (p=0.017) in male students, 2.67 (p=0.001) in 3rd?year students, and 2.92 (p=0.001) in only child students. barrier was 2.62 (p=0.009) in 3rd year students, and 2.95 (p=0.002) in only child students. Benefit was 3.40 (p=0.011) in female students, and 3.43 (p=0.003) in 1st year students. salience was 3.21 (p=0.006) in female students, and 3.24 (p=0.009) in 1st year students. 2. As to oral health belief according to oral?health?related factors, susceptibility and seriousness were 2.69 (p=0.003) and 2.72 (p=0.000), respectively, in the lower?middle class group, 2.83 (p=0.001) and 2.80 (p=0.003), respectively, in the drink taking group, and 2.80 (p=0.000) and 2.75 (p=0.000), respectively, in the low conversation group. barrier was 2.63 (p=0.018) in the lower?middle class group, 2.67 (p=0.021) in the low conversation group, and 2.77 (p=0.000) in the group fearing the visit to the dental clinic. Benefit was 3.36 (p=0.000) in the high conversation group, and 3.37 (p=0.0l5) in the group visiting the dental clinic for prevention. salience was 3.26 for beverage and 3.20 (p=0.003) for fruit and vegetable. 3. As to oral health practice according to general characteristics, the score of oral health practice was 3.21 (p=0.000) in female students, 3.30 (p=0.000) in those aged 12 or below, and 3.27 (p=0.000) in 1st?year students. 4. As to oral health practice according to factors related to oral health, the point was 3.17 (p=0.002) in the middle upper class group, 3.24 (p=0.001) in the group eating mainly fruit or vegetable, and 3.18 (p=0.030) in those with experience in education. 5. Oral health practice was in a negative correlation with susceptibility (r=-0.143), and in a positive correlation with benefit (r=0.229) and salience (r=0.286).

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.333-333
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• 2016

현재까지 가장 높은 광전류 변환 효율을 나타내는 III-V 화합물 반도체의 다중접합 태양전지 대신 이보다 단순한 에피구조를 가진 단일셀 이종접합구조의 태양전지를 제안하였다. 이를 한국나노 기술원에서 MOCVD(Metalorganic Vapour Phase Epitaxy) 장비를 이용하여 에피구조를 성장하고 태양 전지를 제작해 그 특성을 조사하였다. 태양 전지는 서로 다른 orientation의 두 GaAs 기판에 각각 동일한 에피 구조로 성장되었다. GaAs 기판은 Si 도핑된 n-type 기판으로 (100) 표면이 <111>A 방향으로 2도 off 된 웨이퍼와 10도 off 된 웨이퍼가 사용되었다. 연구에서 시뮬레이션에 사용된 태양전지의 에피 구조는 맨 위 p-GaAs (p-contact 층), p-InAlP, p-InGaP의 광흡수층과 N-InAlGaP 층과 아래의 n-InAlP와 n-GaAs의 n-contact층으로 이루어져있다.태양전지는 $5mm{\times}5mm$의 면적을 가지고 있다. 그림 1은 전류-전압의 측정된 결과를 나타낸 그래프이다. 태양전지는 1 sun 조건하에서 probe를 이용해 측정되었다. 2도 off GaAs 기판 위에 성장시킨 태양전지에서는 3.7mA의 단락전류값이, 10도$^{\circ}$ off 인 샘플에서는 4.7mA의 단락전류값이 측정되었다. 반면에 전류-전압곡선으로부터 얻은 10도 off 인 태양전지의 직렬 저항값은 2도 off 인 태양전지의 약4배 정도로 나타났다. 이는 기판의 결정방향에 따라 태양전지의 내부 전하 transport에 차이가 있음을 나타낸다. TLM (Transmission Line Model) 방법에 의한 p-contact의 ohmic저항 측정에서도 이와 일치하는 결과를 얻었다.

• Journal of Pharmaceutical Investigation
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• v.31 no.4
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• pp.225-232
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• 2001

The present study was carried out to observe the effect of liposome dispersed gel formulation (Lipogel) on topical delivery of ascorbyl palmitate (AsP). Neutral and negatively charged MLV liposomes containing AsP were prepared with dimyristoylphosphadtidylcholine (DMPC) and dicetyl phosphate (DCP), and dispersed to poloxamer gel matrix. In the hydrolysis study in rat's skin homogenates, AsP hydrolyzed to ascorbic acid (AsA) according to the first-order kinetics with the rate constant of $2.46{\times}10^{-2}\;min^{-1}$. In the passive skin penetration study using Franz diffusion cell, lipogel systems exhibited the greater values in the flux $(J_s)$ and the amount penetrated $(Q_p)$ compared to control hydrogels containing diethyleneglycol monoethyl ether $(Transcutol^{\circledR})$ as a solubilizing agent and a penetration enhancer for AsP. The total amount penetrated $(Q_{Total})$, which is expressed as a summation of $Q_P\;and\;Q_L$, for lipogel system was about 1.4 times higher in average than that of control hydrogel. However the amount localized in the skin $(Q_L)$ was similar in both formulations. As a result, lipogel system enhanced the skin penetration of AsP, possibly due to the increase in local concentration of AsP by preferential adsorption of liposome to the skin and the enhancing effect of phospholipid in liposome composition. Moreover it was expected that the penetrated AsP would generate AsA during skin penetration by the skin esterase. In conclusion, lipogel formulation was considered as a good candidate for topical delivery of AsP.

• Applied Chemistry for Engineering
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• v.30 no.4
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• pp.499-503
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• 2019

Characteristics of solar cells employing a lattice matched GaInP/GaAs quantum well (QW) structure in a single N-AlGaInP/p-InGaP heterojunction (HJ) were investigated and compared to those of solar cells without QW structure. The epitaxial layers were grown on a p-GaAs substrate with $6^{\circ}$ off the (100) plane toward the <111>A. The heterojunction of solar cell consisted of a 400 nm N-AlGaInP, a 590 nm p-GaInP and 14 periods of a 10 nm GaInP/5 nm GaAs for QW structure and a 800 nm p-GaInP for the HJ structure (control cell). The solar cells were characterized after the anti-reflection coating. The short-circuit current density for $1{\times}1mm^2$ area was $9.61mA/cm^2$ for the solar cell with QW structure while $7.06mA/cm^2$ for HJ control cells. Secondary ion mass spectrometry and external quantum efficiency results suggested that the significant enhancement of $J_{sc}$ and EQE was caused by the suppression of recombination by QW structure.

• Journal of Korea Foresty Energy
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• v.22 no.2
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• pp.1-17
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• 2003

Populus species have been as a model species in tree breeding and we have enormous varieties resulting from the poplar breeding because of their fast growth performance and short rotation age. New varieties developed in Korea are common italian poplar(P euramericana, I-214, I-476), P euramericana“Eco 28”(Italian poplar No.1) and p. deltoides“Lux”(Italian poplar No.2), which were introduced from foreign countries. As hybrid polars, Hyun-Sasi(p. alba ${\times}$ P. glandulosa No.1, No.2, No.3, No4.), P. nigra x P. maximowiczii and P. koreana x P. nigra val. italica, were developed, and P. davidiana was selected as the result of selection breeding The total plantation areas covered with the new varieties are 935,162ha that include 745,773ha of P. euramericana, 184,636ha of P. alba x P. glandulosa, and other new varieties are 4,735ha. The new poplars are contributed to increase farmer's income as well as bare land tree-planting in Korea. The technologies associated with the poplar species were developed, such as the determination of optimum site for new the poplar species, the crossing method between incompatible poplar species, and the vegetative mass propagation. In the future, poplar species will be considered for phytoremediation species at contaminated areas such as landfill sites or with lives stock's waste water as well as wood production, a shade tree like road-side tree and public park tree.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.21-34
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• 2000

Millimeter wave is expected as the unlimited useful frequency resources for the next generation wireless communication services. In the past, its usage was limited to the military warfare due to lack of millimeter devices. The development of GaAs pHEMT in 1980 and the progress in the processing technologies made the new consumer wireless services possible utilizing millimeter waves. Specially, most of passive components necessary for circuit design can be integrated with GaAs pHEMTs and this removes the difficulty in assembly unavoidable in hybrid design. InP based pHEMTs developed later possess all the properties of GaAs and it shows many advantages in higher frequency applications. In this paper, the status and trends of those devices and MMICs are presented and the future developing trends is also described.

• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.186-193
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• 2006

In this study, we analyzed the electrical and optical properties of metalorganic chemical vapor deposition grown InGaAs/InGaAsP/InP quantum dot(QD) molecules by using photoluminescence and deep-level transient spectroscopy. From these resulte, the energy levels of the large QDs are located at deeper region from the conduction band edge of the barrier than that of the small QDs, The large QDs seem to have the energy states more than two, and these energy levels of the QD molecules are located at 0.35, 0.42, and 0.45 eV from conduction band edge under -4 V reverse bias conditions. The energy levels are closely coupled under low reverse bias, and then decoupled as the bias voltage is increased.