• Journal of the Korean Magnetics Society
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• v.15 no.6
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• pp.315-319
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• 2005

To obtain low switching field ($H_{SW}$) we introduced amorphous ferromagnetic $Co_{70.5}Fe_{4,5}Si_{15}B_{10}$ single and synthetic antiferromagnet (SAF) free layers in magnetic tunnel junctions (MTJs). The switching characteristics for MTJs with structures $Si/SiO_2/Ta$ 45/Ru 9.5/IrMn 10/CoFe 7/AlOx/CoFeSiB 7 or CoFeSiB (t)/Ru 1.0/CoFeSiB (7-t)/Ru 60 (in nm) were investigated and compared to MTJs with $Co_{75}Fe_{25}$ and $Ni_{80}Fe_{20}$ free layers. CoFeSiB showed a lower saturation magnetization of $560 emu/cm^3$ and a higher anisotropy constant of $2800\;erg/cm^3$ than CoFe and NiFe, respectively. An exchange coupling energy ($J_{ex}$) of $-0.003erg/cm^2$ was observed by inserting a 1.0 nm Ru layer in between CoFeSiB layers. In the CoFeSiB single and SAF free layer MTJs, it was frond that the size dependence of the $H_{SW}$ originated from the lower $J_{ex}$ experimentally and by micromagnetic simulation based on the Landau-Lisfschitz-Gilbert equation. The CoFeSiB SAF structures showed lower $H_{SW}$ than that of NiFe, CoFe and CoFeSiB single structures. The CoFeSiB SAF structures were proved to be beneficial far the switching characteristics such as reducing the coercivity and increasing the sensitivity in micrometer to submicrometer-sized elements.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.399-407
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• 2009

Laser induced breakdown spectroscopy(LIBS) is an simple analysis method for directly quantifying many kinds of soil micro-elements on site using a small size of laser without pre-treatment at any property of materials(solid, liquid and gas). The purpose of this study were to find an optimum condition of the LIBS measurement including wavelengths for quantifying soil elements, to relate spectral properties to the concentration of soil elements using LIBS as a simultaneous un-breakdown quantitative analysis technology, which can be applied for the safety assessment of agricultural products and precision agriculture, and to compare the results with a standardized chemical analysis method. Soil samples classified as fine-silty, mixed, thermic Typic Hapludalf(Memphis series) from grassland and uplands in Tennessee, USA were collected, crushed, and prepared for further analysis or LIBS measurement. The samples were measured using LIBS ranged from 200 to 600 nm(0.03 nm interval) with a Nd:YAG laser at 532 nm, with a beam energy of 25 mJ per pulse, a pulse width of 5 ns, and a repetition rate of 10 Hz. The optimum wavelength(${\lambda}nm$) of LIBS for estimating soil and plant elements were 308.2 nm for Al, 428.3 nm for Ca, 247.8 nm for T-C, 438.3 nm for Fe, 766.5 nm for K, 85.2 nm for Mg, 330.2 nm for Na, 213.6 nm for P, 180.7 nm for S, 288.2 nm for Si, and 351.9 nm for Ti, respectively. Coefficients of determination($r^2$) of calibration curve using standard reference soil samples for each element from LIBS measurement were ranged from 0.863 to 0.977. In comparison with ICP-AES(Inductively coupled plasma atomic emission spectroscopy) measurement, measurement error in terms of relative standard error were calculated. Silicon dioxide(SiO2) concentration estimated from two methods showed good agreement with -3.5% of relative standard error. The relative standard errors for the other elements were high. It implies that the prediction accuracy is low which might be caused by matrix effect such as particle size and constituent of soils. It is necessary to enhance the measurement and prediction accuracy of LIBS by improving pretreatment process, standard reference soil samples, and measurement method for a reliable quantification method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.183-183
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• 2009

OLED소자의 양극재료로써 현재는 산화인듐주석(ITO : indium tin oxide) 박막이 널리 이용되고 있다. 그러나 낮은 전기 비저항과 높은 투과도를 갖는 ITO 박막을 얻기 위해서는 $300^{\circ}C$ 이상의 고온에서 성막되어야 하며, 원료 물질인 인듐의 수급량 부족으로 인한 문제점과 독성, 저온증착의 어려움, 스퍼터링 시 음이온 충격에 의한 막 손상으로 저항의 증가의 문제점이 있고, 또한 유기발광소자의 투명전극으로 쓰일 경우에 유기물과의 계면 부적합성, 액정디스플레이의 투명전극으로 사용될 경우에 $400^{\circ}C$정도의 놓은 온도와 수소 플라즈마 분위기에서 장시간 노출 시 열화로 인한 광학적 특성변화가 문제가 된다. 이러한 문제점을 지닌 ITO 박막을 대체할 수 있는 물질로 산화 인듐아연(lZO) 박막이 많은 각광을 받고 있다. IZO(Indium Zinc Oxide) 박막은 저온 ($100^{\circ}C$ 이상)에서 증착이 가능하고 추가적인 열처리 없이도 가시광 영역에서 90% 이상의 광 투과도와 ${\sim}10^{-4}{\Omega}cm$ 이하의 낳은 전기 비저항을 갖는 것으로 알려져 있다. 이러한 IZO박막은 성막 후 고온의 열처리 과정이 필요 없기 때문에 폴리카보네이트와 같은 유기물 기판을 사용하여 제작 가능한 유연한 평판형 표시 소자의 제작에도 적용될 수 있다. IZO(Indium Zinc Oxide) 박막은 상온 공정에서도 우수한 전기적, 광학적, 표면 특성을 나타낼 뿐만 아니라 양극재료로써 높은 일함수를 가지고 있어 고효율의 유기 발광 소자를 구현하는데 유리한 재료라 판단된다. 본 연구에서는 TCO 박막의 면 저항과 표면 거칠기가 OLED 소자의 성능에 미치는 영향을 조사하였다. R.F Magnetron Sputtering을 이용하여 투명 전도막을 성막 형성 하였으며, 기판온도와 증착과정에서 주입되는 산소, 수소의 유랑 변화가 박막의 구조적, 전기적 특성에 어떠한 영향 미치는 것인가를 자세히 규명하였다 ITO 와 IZO박막은 챔버 내 다양한 가스 분위기(Ar, $Ar+O_2$ and $Ar+H_2$) 에서 R.F Magnetron Sputtering 방법으로 증착했다. TCO박막의 구조적인 이해를 돕기 위해서 X-ray diffraction 과 FESEM으로 분석했다. 광학적 투과도와 박막의 두께는 Ultraviolet Spectrophotometer(Varian, cary-500)와 Surface profile mersurement system으로 각각 측정하였다. 면저항, charge carrier농도, 그리고 TCO박막의 이동성과 길은 전기적특성은 Four-point probe와 Hall Effect Measurement(HMS-3000)로 각각 측정한다. TCO 박막의 표면 거칠기에 따른 OLED소자의 성능분석 측면에서는 TCO 박막의 표면 거칠기 조절을 위해 photo lithography 공정을 사용하여 TCO 박막을 에칭 하였다. 미세사이즈 패턴 마스크가 사용되고 에칭의 깊이는 에칭시간에 따라 조절한다. TCO박막의 표면 형태는 FESEM과 AFM으로 관찰하고 그리고 나서 유기메탈과 음극 전극을 연속적으로 TCO 박막위에 증착한다. 투명전극으로 사용되는 IZO기판 상용화를 위해 IZO기판 위에 $\alpha$-NPB, Alq3, LiF, Al순서로 OLED소자를 제작하였다. 전류밀도와 전압 그리고 발광과 OLED소자의 전압과 같은 전기적 특성은 Spectrometer (minolta CS-1000A) 에 의하여 I-V-L분석을 했다.

• Research in Community and Public Health Nursing
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• v.9 no.2
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• pp.502-517
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• 1998

This research intends to survey family environment, health behavior and health status of the students in urban-rural elementary schools and analyze those factors comparatively, and use the result as basic material for school health teacher to teach health education in connection with family and regional areas. It also intends to improve a pupil's self-abilitiy in health care. The subjects involve 2,774 students of urban elementary schools and 583 student in rural ones, who were selected by means of a multi -stage probability sampling. Using the questionnaire and school documents, we collected data on family environment, health behavior and health status for 19 days. Feb. 2nd 1998 through Feb. 20th 1998. The R -form of Family Environment Scale (Moos, 1974) was used in the analysis of family environment(Cronbach's Alpha =0.80). Questionnaires of Health Behavior in School-aged children used by the WHO in Europe(Aaro et al., 1986) and the ones developed by the Health Promotion Committee of the Western Pacific(WHO, 1995)(adapted by long Young-suk and Moon Young-hee(1996)) were used in the analysis of health behavior, as well documents on absences due to sickness, school health room-visits, levels of physical strength, height, weight and degree of obesity were used to determine health status. In next step, We used them with an $X^2$-test, t-test, Odds Ratio, and a 95% Confidence Interval. 1. In two dimensions of three, family-relationship (t=3.41, p=0.001) and system -maintenances(t= 2.41, p=0.0l6) the mean score of urban children were significantly higher than those of rural ones. In the personal development dimension however, there was little significant difference. Assorting family environment into 10 sub-fields and analyzing them, we recognized that urban children were superior to rural children in the sub-fields of expressiveness (t =3.47, p=0.001), conflict (t=0.48, p=0.001), active-recreational orientation (t = 1.97, p=0.049) and organization (t=4.33, p=0.000). 2. Referring to the Odds Ratios of urban-rural children's health behaviors, urban children set up more desirable behavior than rural children wear ing safety belts (Odds Ratio =0.32, p=0.000), washing hands after meals(Odds Ratio = 0.43, p= 0.000), washing hands after excreting (Odds Ratio = 0.39, p=O.OOO), washing hands after coming - home ( Odds Ratio = 0.75, p = 0.003), brushing teeth before sleeping(Odds Ratio =0.45, p=0.000), brushing teeth more than once a day (Odds Ratio =0.73, p=0.0l2), drinking boiled water (Odds Ratio = 0.49, p=0.000), collecting garbage at home(Odds Ratio=0.31, p=0.000) and in the school(Odds Ratio =0. 67, p=0.000). All these led to significant differences. As to taking milk(Odds Ratio = 1.50, p=0.000), taking care of eyesight(Odds Ratio=1.41, p=0.001) and getting physical exercise in(Odds Ratio = 1.33, p=0.0l9) and outside the school(Odds Ratio = 1.32, p=0.005), rural children had more desirable behavior which also revealed a significant difference. There was little significant difference in smoking, but the smoking rate of rural children(5.5%) was larger than that of urban children(3.9%). 3. Health status was analyzed in terms of absences, school health room-visits, levels of physical strength, and the degree of obesity, height and weight. Considering Odds Ratios of the health status of urban-rural children, the health status of rural children was significantly better than that of the urban ones in the level of physical strength(t=1.51, p=0.000) and the degree of obesity(t=1.84, p=0.000). The mean height of urban children ($150.4{\pm}7.5cm$) is taller than that of their counterparts($149.5{\pm}7.9$), which revealed a significant difference (t =2.47, p=0.0l4). The mean weight of urban children($42.9{\pm}8.6kg$) is larger than that of their counterparts($41.8{\pm}9.0kg$), which was also a significant difference(t=2.81, p=0.005). Considering the results above, we can recognize that there are significant differences in family environment, health behavior, and health status in urban-rural children. These results also suggestion ideas for health education. What we would suggest for the health program of elementary schools is that school health teachers should play an active role in promoting the need and importance of health education, develop the appropriate programs which correspond to the regional characteristics, and incorporate them into schools to improve children's ability to manage their own health management.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.1
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• pp.13-22
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• 1977

The following results were obtained in this work intended for getting more informations on features of phosphorus in Korean characteristic virgin, upland and paddy soils for knowing the ways how to evaluate the soil phosphorus availability and utilize fertilizers efficiently. 1. A large part of soil phosphorus is occupied by inorganic phosphorus in the soils of which the cultivated soils showed higher accumulation of applied phosphorus as inorganic forms than the uncultivated soils. The accumulation of organic phosphorus was indicated the highest in the paddy soils, and the lowest in the uncultivated soils. Than the cultuivated soil, the uncultivated soils have higher C/P ratio which was estimated to be related to soil fertility status essentially. 2. Iron phosphate was shown to be the most dominant form in soil phosphorus. Difference in parent rocks, from which the soils were originated, was shown to affect the carious distribution of phosphorus forms in the uncultivated soils to a large extent. The paddy soils have almost same distribution pattern of soil phosphorus forms regardless of different parent rocks. 3. The different methods for available phosphorus estimation extracted different amounts of phosphorus from the soils. Close relations between the available phosphours extracted with the different methods and the amounts of seil inorganic phosphorus were shown : e.g. between Fe-P and available-P by Olsen method. 4. Phosphorus absorption coefficient correlated negatively to soil inorganic phosphorus, and also to available phosphorus extracted with the several methods.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.345-359
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• 2006

Loss of maxillary molar teeth leads to rapid loss of crestal bone and inferior expansion of the maxillary sinus floor (secondary pneumatization). Rehabilitation of the site with osseointegrated dental implants often represents a clinical challenge because of the insufficient bone volume resulted from this phenomenon. Boyne & James proposed the classic procedure for maxillary sinus floor elevation entails preparation of a trap door including the Schneiderian membrane in the lateral sinus wall. Summers proposed another non-invasive method using a set of osteotome and the osteotome sinus floor elevation (OSFE) was proposed for implant sites with at least 5-6mm of bone between the alveolar crest and the maxillary sinus floor. The change of grafted material in maxillary sinus is important for implant survival and the evaluation of graft height after maxillary sinus floor elevation is composed of histologic evaluation and radiomorphometric evaluation. The aim of the present study was radiographically evaluate the graft height change after maxillary sinus floor elevation and the influence of the graft material type in height change and the bone remodeling of grafts in sinus. A total of 59 patients (28 in lateral approach and 31 in crestal approach) who underwent maxillary sinus floor elevation composed of lateral approach and crestal approach were radiographically followed for up to about 48 months. Change in sinusgraft height were calculated with respect to implant length (IL) and grafted sinus height(BL). It was evaluated the change of the graft height according to time, the influence of the approach technique (staged approach and simultaneous approach) in lateral approach to change of the graft height, and the influence of the type of graft materials to change of the graft height. Patients were divided into three class based on the height of the grafted sinus floor relative to the implant apex and evaluated the proportion change of that class (Class I, in which the grafted sinus floor was above the implant apex; Class II, in which the implant apex was level with the grafted sinus floor; and Class III, in which the grafted sinus floor was below the implant apex). And it was evaluated th bone remodeling in sinus during 12 months using SGRl(by $Br\ddot{a}gger$ et al). The result was like that; Sinus graft height decreased significantly in both lateral approach and crestal approach in first 12 months (p$MBCP^{TM}$ had minimum height loss. Class III and Class II was increased by time in both lateral and crestal approach and Class I was decreased by time. SGRI was increased statistically significantly from baseline to 3 months and 3 months(p<0.05) to 12 months(p$ICB^{(R)}$ single use, more reduction of sinusgraft height was appeared. Therefore we speculated that the mixture of graft materials is preferable as a reduction of graft materials. Increasing of the SGRI as time goes by explains the stability of implant, but additional histologic or computed tomographic study will be needed for accurate conclusion. From the radiographic evaluation, we come to know that placement of dental implant with sinus floor elevation is an effective procedure in atrophic maxillary reconstruction.

• Journal of Korean Philosophical Society
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• v.105
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• pp.49-74
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• 2008

Le but de notre recherche est $d^{\prime}{\acute{e}}clairer$ la nature du $d{\acute{e}}passement$ de soi aux actes humaines dnas le Thomisme. Dans le Thomisme la nature humaine qui a la raison et la $volont{\acute{e}}$ a une $intentionnalit{\acute{e}}$ ver la fin ultime. De sorte que les actes humaines qui $corr{\grave{e}}spondent$ cette nature humaine a un $caract{\grave{e}}re$ du $d{\acute{e}}passement$ de soi visant toujours plus que le $pr{\acute{e}}sent$. Le fondement de cet acte du $d{\acute{e}}passement$ de soi est $l^{\prime}{\hat{a}}me$ rationelle qui est la forme substantielle de l'homme et de soi subsistante. Chez st. Thomas ce $caract{\grave{e}}re$ du $d{\acute{e}}passement$ a trois ${\acute{e}}taps$ distinctes : (1)le $d{\acute{e}}passement$ dans l'ordre du $progr{\grave{e}}s$ naturel (2)le $d{\acute{e}}passement$ de soi dans l'ordre morale (3)le $d{\acute{e}}passement$ de soi dans l'ordre de la religion. Le $d{\acute{e}}passement$ dans l'ordre du $progr{\grave{e}}s$ naturel apparaît d'abord au $caract{\grave{e}}re$ de $l^{\prime}{\hat{a}}me$ rationelle. St. Thomas $d{\acute{e}}finit$ les vertus rationelles comme $^{\prime}pl{\acute{e}}nitude$ dans le $f{\acute{e}}blesse$, parce qu'il $consid{\grave{e}}re$ la vertu rationelle comme $finalit{\acute{e}}$ des $facult{\acute{e}}s$ du sens $ext{\acute{e}}rieur$. L'homme par le sens $ext{\acute{e}}rieur$ reçoit des $esp{\grave{e}}ces$ sensibles(especies sensibilis), et $poss{\grave{e}}de$ les images. Puis cette images sensible devenant la $r{\acute{e}}alit{\acute{e}}$ spirituelle sous forme du $m{\acute{e}}moire$ et du souvenir, devient aussi la partie de son existence. Donc chez st. Thomas la vertue rationnelle n'est pas simplement un $facult{\acute{e}}$ $sp{\acute{e}}culative$, mais elle est dans l'ordre du devenir et du $pl{\acute{e}}nitude$. A cette raison st. Thomas compare la raison(ratio) comme $g{\acute{e}}n{\acute{e}}ration$(generatio) et l'intelleigence(intellectus) comme ${\hat{e}}tre$(esse). C'est-${\grave{a}}$-dire la raison $d{\acute{e}}passe$ le sensible et l'intelligence $d{\acute{e}}passe$ la raison. Le $d{\acute{e}}passement$ de soi dans l'ordre morale $li{\acute{e}}$ au $progr{\grave{e}}s$ de la conscience. Chez st. Thomas la perception de l'objet $ext{\acute{e}}rieur$ ayant pour but d'avoir conscience de soi, se perfectionne ${\grave{a}}$ ceci. D'avoir conscience de soi signifie d'avoir $l^{\prime}identit{\acute{e}}$ de soi, et de-$l{\grave{a}}$ apparaît l'acte moral en tnat qu'acte $sp{\acute{e}}cifique$ humain. La raison pour laquelle la vie morale elle-$m{\hat{e}}me$ a un $caract{\grave{e}}$ du $d{\acute{e}}passement$, c'est que l'acte humaine qui corresfonde ${\grave{a}}$ $l^{\prime}identit{\acute{e}}$ du soi est une vie qui vise toujours plus que le $pr{\acute{e}}sent$ ou $l^{\prime}id{\acute{e}}al$. Quant au problem du $d{\acute{e}}passement$ dans l'ordre de la religion, chez st. Thomas en raison de $l^{\prime}affinit{\acute{e}}$ entre Dieu et l'homme, $o{\grave{u}}$ il y a des vertues infuses(virtutes infusas), il y a une sorte du $d{\acute{e}}passement$ religieux. Car ces vertues infuses signifie la communication entre Dieu(${\hat{E}}tre$ absolu) et l'homme(${\hat{e}}tre$ fine) et cela signifie le $d{\acute{e}}passement$ de l'humain vers le divin. Cette $id{\acute{e}}e$ thomiste permet de penser que $o{\grave{u}}$ il y a un $d{\acute{e}}passement$ de soi dans la vie religuse d'une personne, il y a une intervention $r{\acute{e}}elle$ de la providence divine. Cette $pens{\acute{e}}e$ thomiste sera alors un $caract{\grave{e}}$ $r{\acute{e}}aliste$ face ${\grave{a}}$ la $pens{\acute{e}}e$ $id{\acute{e}}aliste$ qui n'admette que le $d{\acute{e}}passement$ absolu comme $d{\acute{e}}passement$ religieux.