• 한국인구학
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• 제13권2호
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• pp.1-18
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• 1990

This is a study which attempt to analyze changing patierns of economic active popu-lation, t o estimato- future patterns, and exa- mine vartons problems arises by changing c ire u mst ances of t he labor force market in- clunging soici al, economic ic, heathl th and demoi-graph ic aspects. We have constructed series of wotking life table which are useful in syt uiolyioig the lirocess of growth and structural change of labor force. Work i ng life tables represent ihie life eyele of econrmic' activity in hi ypothetical cohorts, that is. gen-erat i on of men Sn bject at eat' b period ot f their lives th given ra to's o mor tali it y and of par-- tici pation in economic activities. The tabloes prot' ide measorues of the alvet'age he ng t able of economically aeti \- e life. and agespecific rates of en trannee' into and retirement from the hahn' force. In const routing working life tables, age-specific activity rates and life tabole popula- titoto which represents contemporary condi-tions of moortality in Korea au'e the basic' maltoerials. We have derived the age-specific rates foorm economically active population survey, whoich were conducted by the Bureau of Statistics, Economic Planning Borard of the Korean government. Working life tables are constructed for men wtable these materi- als in the year of 1970, 1980 and 1988 by a modified Wolfbein-Wool's method. Some of the findings may be summerized as follow : 1) A central part of constructing working life table is calculation of stationary' economic active population, which represents the number of men in the stationtary population extoected to be in the labor force at each age group in the life span. The stationary economic active population by age have generally a universal pattern, where they rise sharply in the early twenties, approach its' peak in the thirties decline thereafter. at first graolually and then more rapidly at an advanced age. Korean men show the same general pa ttern of age distribution of stationary eco-- nomic active population with sharp increase hegining from the age interval of 20 to 24, reaching to maximum level at older age. The population. however, presumably, increased substantially due to increaseing school atte endance rates. Another difference exiSts in the youngest age groups, that is the activity rate in the year of 1988 is lower than that of Japan. The table shows an analysis of changes in the age distrihution of labor force between 1970, 1980 and 1988. 2) It was shown an analysis of changes in the age distribution and cause of separation from labor force. The entrance rate to labor force has increased from 18~\5 persons to 299 persons per 1000 head of stationary population between that of 1980 than that of 1988 for Korean men in 20~24 age group. The entrace rate to labor force shows a rapid entrance appearance concentrated on the 15~24 age group. The separation rate from labor force by retirment in Korea in the year of 1988 shows a great difference of the about four times as much as that of Japan. 3) The functions of table illustrate the patterns of working life of males in Korea in 1970, 1980 and 1988. The average remaining number of economically active years, e at age 15 in 1988 is 46.39 which is 2.12 years of increase compared with that of at age 15 in 1970,1980 and 1988 are 43.90,44.27 and 46.39 respectively, showing steadily increase dur- ing the past double decade the increase in the length of economically active life various age may be considered to have come both from extention of general life expectancy and from increasing entrance rate to economic activity in high age that of working is far greater in 1988 than that of 1980. The gaps between expectation of life and average remaining years of economically active widened due to rapid improvement of mortality level in Ko- rea. This observation together with the population pressure by the appearance of a group of younger population implies that constant increase of economically inactive population among older age group.

• Journal of Periodontal and Implant Science
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• 제26권2호
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• pp.448-468
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• 1996

To maintain its functional integrity, bone is continuously remodelled by a process involving resorption by osteoeclasts and formation by osteoblasts, In order to respond to changes in the physical environment or to trauma with the relevant action, this process is strictly regulated by locally synthesized or systemic fators, Prostaglandin $E_2(PGE_2$) is perhaps one of the best studied factors, having been known to affect bone cell function for several decades.$PGE_2$ has both anabolic and catabolic activities. Excess of $PGE_2$ has been implicated in a number of pathological states associated with bone loss in a number of chronic inflammatory conditions such as periodontal disease and rheumatoid arthritis. $PGE_2$ and other arachidonic acid metabolites have been shown to be potent stimulators of osteoclastic bone resorption in organ culture. The anabolic effects of $PGE_2$ were first noticed when an increase in periosteal woven bone formation was seen after the infusion of $PGE_2$ into infants in order to prevent closure of the ductus arteriosus. The cellular basis for the catabolic actions of $PGE_2$ has been well characterized. $PGE_2$increases osteoclast recruitment in bone marrow cell cultures. Also $PGE_2$ has a direct action on osteoclast serving to inhibit activity and can also indirectly activate osteoclast via other cells in the vicinity, presumably osteoblast. The cellular mechanisms for the anabolic actions of $PGE_2$ are not nearly so well understood. The purpose of this paper was to study the effects of $PGE_2$ and dibutyl(DB)cAMP on osteoblastic clone MC3T3El cells and on the generation of osteoclasts from their precursor cells. The effect of $PGE_2$ and DBcAMP on the induction of alkaline phoaphatase(AlP) was investigated in osteoblastic clone MC3T3El cells cultured in medium containing 0.4% fetal bovine serum. $PGE_2$ and DBcAMP stimulated ALP activity and MTT assay in the cells in a dose-dependent manner at concentrations of lO-SOOng/ml. Cycloheximide, protein synthesis inhibitor, inhibited the stimulative effect of $PGE_2$ and DBcAMP on ALP activity in the cells. $PGE_2$also increased the intracellular cAMP content in a dose-dependent fashion with a maximal effect at 500ng/ml. The effect of $PGE_2$ on the generation of osteoclasts was investigated in a coculture system of mouse bone marrow cells with primary osteoblastic cells cultured in media containing 10% fetal bovine serum.After cultures, staining for tartrate-resistant acid phosphatase(TRAP)-marker enzyme of osteoclast was performed. The TRAP(+) multinucleated cells(MNCs), which have 3 or more nuclei, were counted. More TRAP(+) MNCs were formed in coculture system than in control group. $PGE_2(10^{-5}10^{-6}M)$ stimulated the formation of osteoclast cells from mouse bone marrow cells in culture. $PGE_2(10^{-6}M)$ stimulated the formation of osteoclast cells from mouse bone marrow cells in coculture of osteoblastic clone MC3T3E1 cells This results suggest that $PGE_2$ stimulates the differentiation of osteoblasts and generation of osteoclast, and are involved in bone formation, as well as in bone resorption.

• Asia pacific journal of information systems
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• 제18권3호
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• pp.45-65
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• 2008

The rapid growth of the Internet has increased the amount of transmission of personally identifiable information. At the same time, with new Internet related technologies, organizations are trying to collect and access more personal information than before, which in turn makes individuals concern more about their information privacy. For their successful businesses, organizations have tried to alleviate these concerns in two ways: (1) by offering privacy policies that promise certain level of privacy protection; (2) by offering benefits such as financial gains or convenience. In this paper, we interpret these actions in the context of the information processing theory of motivation. This paper follows Hann et al.(2007)'s methods to analyze Internet users privacy concerns in Korea and tries to compare the findings. Our research objectives are as follows: First, we analyze privacy concern mitigation strategies in the framework of the expectancy theory of motivation. Subsequently, we show how the expectancy theory based framework is linked o the conjoint analysis. We empirically validate the predictions that the means to mitigate privacy concerns are associated with positive valences resulting in an increase in motivational score. In order to accommodate real-life contexts, we investigate these means in trade-off situation, where an organization may only be able to offer partially complete privacy protection and/or promotions and/or convenience, While privacy protection (secondary use, improper access) are associated with positive valences, we also find that financial gains can significantly increase the individuals' motivational score of a website in Korea. One important implication of this empirical analysis is that organizations may possess means to actively manage the privacy concerns of Internet users. Our findings show that privacy policies are valued by users in Korea just as in the US or Singapore. Hence, organizations can capitalize on this, by stating their privacy policy more prominently. Also organizations would better think of strategies or means that may increase online users' willingness to provide personal information. Since financial incentives also significantly increase the individuals' motivational score of website participation, we can quantify the value of website privacy protection in terms of monetary gains. We find that Korean Internet users value the total privacy protection (protection against errors, improper access, and secondary use of personal information) as worthy as KW 25,550, which is about US 28. Having done this conjoint analysis, we next adopt cluster analysis methodology. We identify two distinct segments of Korea's internet users-privacy guardians and information sellers, and convenience seekers. The immediate implication of our study is that firms with online presence must differentiate their services to serve these distinct segments to best meet the needs of segments with differing trade-offs between money and privacy concerns. Information sellers are distinguished from privacy guardians by prior experience of information provision, To the extent that businesses cannot observe an individual's prior experience, they must use indirect methods to induce segmentation by self-selection as suggested in classic economics literature of price discrimination, Businesses could use monetary rewards to attract information sellers to provide personal information. One step forward from the societal trends that emphasize the need of legal protection of information privacy, our study wants to encourage organizations and related authorities to have the viewpoints to consider both importance of privacy protection and the necessity of information trade for the growth of e-commerce.

• 대한전자공학회논문지TC
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• 제45권10호
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• pp.65-70
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• 2008

본 연구에서는 94 GHz 송수신 시스템에 응용이 가능한 평면형 회로 내의 전송 선로 방식의 하나인 CPW(Coplanar Waveguide)와 구형 도파관 간의 신호를 원활히 전달해주는 94 GHz CPW-구형 도파관 변환기를 설계하고 제작하였다. 제안된 변환기는 단일 면에 구현된 Fin-line 테이퍼와 Open 타입의 CPW-Slot-line 변환기 구조로 구성되어 있으며, 이는 MMIC의 플립칩 본딩을 위해 기존의 MMIC 기술을 이용하여 단단하고 구부러지지 않는 사파이어($Al_2O_3$)기판위에 구현되었다. Ansoft사의 HFSS 툴을 이용하여 최적화된 Single-section 변환기를 Back-to-back 구조의 지그로 제작하였고 Anritsu ME7808A Vector Network Analyzer 장비를 이용해 $85{\sim}105$ GHz를 대역에서 S-파라미터들을 측정하였다. 측정 결과, 3 mm 길이를 갖는 CPW의 삽입 손실을 고려하여 94 GHz에서 약 1.7 dB의 삽입 손실과 25 dB 이상의 반사손실을 확인 하였다.

• 한국결정성장학회지
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• 제17권1호
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• pp.6-10
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• 2007

R-plane 사파이어 위에 a-plane GaN층이 성장된 기판에 혼합소스 HVPE(mixed-source hydride vapor phase epitaxy) 방법으로 GaN/InGaN의 이종접합구조(heterostructure)를 구현하였다. GaN/InGaN 이종접합구조는 GaN, InGaN, Mg-doped GaN 층으로 구성되어 있다. 각 층의 성장온도는 GaN층은 $820^{\circ}C$, InGaN 층은 $850^{\circ}C$, Mg-doped GaN 층은 $1050^{\circ}C$에서 성장하였다. 이때의 $NH_3$와 HCl 가스의 유량은 각각 500 sccm, 10 sccm 이었다. SAG-GaN/InGaN 이종접합구조의 상온 EL (electroluminescence) 특성은 중심파장은 462 nm, 반치폭(FWHM : full width at half maximum) 은 0.67eV 이었다. 이 결과로부터 r-plane 사파이어 기판위에 multi-sliding boat system의 혼합소스 HVPE 방법으로 이종접합구조의 성장이 가능함을 확인하였다.

• 청정기술
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• 제17권1호
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• pp.56-61
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• 2011

감압잔사유를 고압 회분식 반응기에 넣고, 상용 Ni-Mo/$Al_2O_3$ 촉매를 이용하여 $450^{\circ}C$, $500^{\circ}C$에서 수첨분해하였다. 그리고 반응 생성물을 단증류 혹은 GC-SIMDIS 방법으로 각각 분석하였다. 먼저 수첨분해반응에서는 두 온도 조건 모두 촉매 반응뿐만 아니라 열분해 반응도 같이 일어나고 있음을 확인하였고, 온도가 증가할수록 전환율이 증가하고, 생성물 중 가솔린 및 납사 비율이 높아졌다. 생성물 분석 결과, $500^{\circ}C$ 반응에서는 단증류와 GC-SIMDIS 분석 결과의 차이가 없었지만, $450^{\circ}C$ 반응에서는 단증류에서는 디젤이, GC-SIMDIS에서는 vacuum gas oil이 주 생성물로 드러났다. 이는 $450^{\circ}C$ 반응에서의 단증류 분석은 단증류에 의한 열분해 반응으로 인해 생성물의 선택도가 정확하지 않음을 알려준다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.127.1-127.1
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• 2011

In this paper, ZnO:Al thin films with c-axis preferred orientation were prepared on Soda lime glass substrates by RF magnetron sputtering technique. AZO thin film were prepared in order to clarify optimum conditions for growth of the thin film depending upon process, and then by changing a number of deposition conditions and substrate temperature conditions variously, structural and electrical characteristics were measured. For the manufacture of the AZO were vapor-deposited in the named order. It is well-known that post-annealing is an important method to improve crystal quality. For the annealing process, the dislocation nd other defects arise in the material and adsorption/decomposition occurs. The XRD patterns of the AZO films deposited with grey theory prediction design, annealed in a vacuum ambient($2.0{\times}10-3$Torr)at temperatures of 200, 300, 400 and $500^{\circ}C$ for a period of 30min. The diffraction patterns of all the films show the AZO films had a hexagonal wurtzite structure with a preferential orientation along the c-axis perpendicular to the substrate surface. As can be seen, the (002)peak intensities of the AZO films became more intense and sharper when the annealing temperature increased. On the other hand, When the annealing temperature was $500^{\circ}C$ the peak intensity decreased. The surface morphologies and surface toughness of films were examined by atomic force microscopy(AFM, XE-100, PSIA). Electrical resistivity, Gall mobility and carrier concentration were measured by Hall effect measuring system (HL5500PC, Accent optical Technology, USA). The optical absorption spectra of films in the ultraviolet-visibleinfrared( UV-Vis-IR) region were recorder by the UV spectrophotometer(U-3501, Hitachi, Japan). The resistivity, carrier concentration, and Hall mobility of ZnS deposited on glass substrate as a function of post-annealing.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.83-83
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• 2017

생체재료의 표면은 이식과 동시에 생체계면의 역할을 하게 되어, 일련의 생물학적 반응이 시작되고 진행되는 중요한 장소가 된다. 초기에 생체계면에서 일어나는 단백질 흡착이나 염증반응을 비롯한 생물학적 반응들은 궁극적으로 임플란트의 성패를 좌우할 만큼 중요하다. 골융합을 개선하기 위한 다른 방법으로 생체불활성의 타이타늄 (Ti)과 골조직의 능동적인 반응을 이루기 위해 생체활성 표면을 부여함으로서 계면에서의 골형성 반응을 증진시키는 방법이 이용된다. 생체불활성의 Ti과 Ti합금은 골조직과 직접적인 결합을 이루지 못하므로, 골조직과의 반응을 향상하기 위해 여러 종류의 생체활성 재료를 코팅하는 방법이 연구되어 왔고, 이 중 생체의 변화와 가장 유사한 하이드록시아파타이트 코팅이 가장 대중적인 방법으로 사용되었으며 이는 초기 골형성을 촉진하는 것으로 알려졌다. 치과용 임플란트의 표면형상과 화학조성이 골 융합에 영향을 미치는 가장 중요한 인자이므로 최근의 연구동향은 이들 두 가지 표면특성을 결합함으로서 결과적으로 최적의 골세포반응을 유도하고, 골융합 후 골조직과의 micromechanical interlocking에 의해 임플란트의 안정성에 중요한 역할을 하는 마이크론 단위의 표면조도와 표면 구조를 유지하면서, 부가적으로 골 조직 반응을 능동적으로 개선할 수 있는 생체활성 성분을 부여하여 골 융합에 상승효과를 이루기 위한 표면처리법에 관해 많은 연구가 요구되어지고 있다. 따라서 골을 구하는 원소인 망간과 실리콘으로 치환된 하이드록시아파타이트를 플라즈마 전해 산화법으로 코팅하여 세포와 잘 결합할 수 있는 표면을 제공함으로써 골 융합과 치유기간을 단축시킬 수 있을 것으로 사료된다. 실험방법은 시편은 치과 임플란트 제작 합금인 Ti-6Al-4V ELI disk (grade 5, Timet Co., USA; diameter, 10 mm, thickness, 3 mm)이며, calcium acetate monohydrate, calcium glycerophosphate, manganese(II) acetate tetrahydrate, sodium metasilicate을 설계조건에 따라 혼합 제조된 전해질 용액을 이용하여 플라즈마 전해 산화법으로 표면 코팅을 실시하였다. 각 시편의 플라즈마 전해시 전압은 280V로 인가하였고, 전류밀도는 70mA로 정전류를 공급하여 해당 인가전압 도달 후 3분 동안 정전압 방식을 유지하였다. 코팅된 피막 표면을 주사전자현미경과 X-선 회절분석을 통하여 미세구조 및 결정상을 관찰하였다. 또한 코팅된 표면의 생체활성 평가는 정량적으로 평가하기 위해 동전위시험과 AC 임피던스를 통하여 시행하였다. 분극거동을 확인하기 위해 potentiostat (Model PARSTAT 2273, EG&G, USA)을 이용하여 구강 내 환경과 유사한 $36.5{\pm}1^{\circ}C$의 0.9 wt.% NaCl에서 실시하였다. 전기화학적 부식 거동은 potentiodynamic 방법으로 조사하였고 인가전위는 -1500 mV에서 2000 mV까지 분당 1.67 mV/min 의 주사속도로 인가하여 시험을 수행하였다. 임피던스 측정은 potentiostat (Model PARSTAT 2273, EG&G, USA)을 이용하였으며, 측정에 사용한 주파수 영역은 10mHz ~ 100kHz 까지의 범위로 하여 조사하였고 ZSimWin(Princeton applied Research, USA) 소프트웨어를 사용하여 용액의 저항, 분극 저항 값을 산출하였다. 망간의 함량이 증가할수록 불규칙한 기공을 보였으며, 실리콘은 $TiO_2$ 산화막 형성을 저해하는 경향을 확인할 수 있었다. 단독으로 표면을 처리한 경우보다 두 가지 원소를 이용해 복합 표면처리를 시행한 경우가 내식성이 좋아 임플란트과의 골 유착에 긍정적인 영향을 미칠 것으로 사료된다.

• 한국가금학회:학술대회논문집
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• 한국가금학회 2001년도 제18차 정기총회 및 학술발표 PROCEEDINGS
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• pp.86-88
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• 2001

본 시험은 broiler performance, litter N농도가 어떻게 유지되며, NH3 gas 농도가 사료에 ammino acid와 Vitamin D를 보충하여 litter에 Alum을 첨가하여 저수준 단백질 수준을 감소시키는지 결정하기 위해 실시하였다. 이 실험은 각각 처리마다 3반복 90마리를 세가지의 다른 단백질 수준을 가지고서 starter period(1-214)와 grower period(22-420)로 나누었다. 단백질처리는 각기 starter에는 평균 23.0(control 71), 20.4(W)와 18.0(73)%로 grower에서는 21.0(control 71), l9.3(n) and 17.o(73)%로 구성된다. control과 비교하면 ammino acid 수준은 비슷하다. Alum은 rice bran kg당 2009에 Control을 제외하고 각 처리구에 혼합했다. 결과는 3wks와 6wks 동안 급여한 사료에서 Control이하인 저수준 단백질은 feed gain은 증가하였으며, feed intake와 weight gain은 감소하였다. 그러나 처리간에는 유의차(P<0.05)가 없었으며 Alum을 litter에 혼합할 때(P<0.05) 저수준 단백질은 NH3 gas농도가 74.8-80.9% 감소되었다. litter에 Alum을 첨가하는 조작은 NH3 gas농도를 감소시킨다는 것을 보여준다.

• Applied Microscopy
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• 제41권2호
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• pp.139-145
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• 2011

담쟁이덩굴(Parthenocissus tricuspidata)은 줄기에 형성된 흡착근으로 접촉 물체표면에 부착하여 식물체를 여러 방향으로 자라게 한다. 이들 흡착근은 접촉면에 일단 착생하면 잘 떨어지지 않는 부착 특성을 지닌다. 본 연구에서는 적벽돌 벽면에 담쟁이덩굴 부착 시 수반되는 흡착근과 벽면 간의 구조적 변화와 함유하는 성분 간의 연관성에 초점을 두어 주사전자현미경과 에너지 분산 X-선 분광분석법으로 비교 연구하였다. 담쟁이덩굴의 흡착근은 적벽돌 표면에 강력 착생하여 벽면을 피복하며 거의 모든 방향으로 생장한다. 이들이 벽 표면에 접촉하는 경우, 흡착근 배축면 내부조직에서 분비하는 점액성 물질에 의해 흡착근-접촉면 간에 상호작용이 일어난다. 접촉면 상에 있는 거친 표면이나 간극 또는 미세한 틈 사이로 침적된 분비물질들에 의해 흡착근과 접촉면은 빈틈없이 밀착된다. 강력 착생한 흡착근조직 내 세포들은 이미 사멸되고, 접촉면에 분비된 물질과 뒤엉키며 수축되어 벽면에서 잘 분리되지 않는 강력한 착생구조체로 변형된다. 접촉면에 착생하였던 흡착근을 분리하여 하피 표면부위에 함유된 원소를 분석한 결과, 이들 흡착근조직의 표면부위에서 적벽돌을 구성하는 주요 성분들이 거의 검출되었다. 이는 착생 전 후 흡착근- 접촉면 사이에서 진행된 물리적인 밀착 및 부착이 구조적 변형과 성분간의 상호작용을 초래하는 것으로 밝혀졌다.