바나듐이 도핑된 강유전체 Bi₄Ti₃O_12 박막(BTV)의 성장과 특성

정원태,최은경,김현주,강민진,김상수 昌原大學校 基礎科學硏究所 2001 基礎科學硏究所論文集 Vol.13 No.-

Bi3.99Ti2.97V0.03O12 (BTV) thin films with 3 mol% vanadium doping were prepared on Pt/Ti/SiO2/Si substrate by sol-gel method. X-ray diffraction analysis indicated that single-phase lapered perovskite were obtained and preferred orientation was not observed. Under the annealing temperature at 600℃, the surface morphology of the BTV thin films had fine-rounded particles and then changed plate-like at 650℃ and 700℃. The remanent polarization (2Pr) and coercive field (2Ec) of 700℃ annealed BTV thin film were 25 μC/cm2 and 116 kV/cm, respectively. In addition, BTV thin film showed little polarization fatigue during 109 switching cycles. These improved ferroelectric properties were attributed to the increased rattling space and reduced oxygen vacancies by substitution Ti4+ ion (68 pm) with smaller V5+ ion (59 pm). The dielectric constant and loss were measured 130 and 0.03 at 10 kHz, respectively.

칼라 문서에서 문자 영역 추출을 위한 클러스터링 기법

정원일,김의정 大田産業大學校 1997 한밭대학교 논문집 Vol.14 No.1

In charater recognition systems, it is very important to extract characters. Recently, color documents are frequently used, and character recognition systems must process these. So, in this paper we study an extraction method of color documents using K-means algorithm, and propose s distance measure based on the relation of color coordinates in the character extraction stage. First, RGB color components in a color document are transformed HSI color coordinate. Then, the K-means algorithm is applied to HSI color indecxes using a distance measure that considers relation among hue, saturation and intensity. We tested complex color documents with noise, and the proposed distance measure was effective in extracting character regions.

內部監査와 外部監査 機能의 强化에 관한 硏究

元亭淵 漢陽大學校 産業經營硏究所 1998 産業經營硏究 Vol.10 No.-

게이트 산화전 RCA세정 횟수에 따른 Si/SiO₂계의 절연특성에 관한 연구

정양희,유일현,한원열 麗水水産大學校産業技術硏究所 1998 産業基術硏究所 論文集 Vol.7 No.-

The purity of wafer surface is an essential requisite for the successful fabrication of VLSI silicon circuits. The solution used in the cleaning step of silicon wafer surfaces known as "RCA standard clean" has the volume ratios NH₄OH : H₂O₂: H₂O=1:1:5. This RCA cleaning process for bare wafer can affect the state of wafer surfaces. This can cause the degeneration of gate oxide layer. For the investigation of this problem, we measured the Dit(interface trap density) of Si/SiO₂system using the C-V method. The Dit is in the range of 0.89∼2.13×10¹¹[cm-²eV-¹]. This measure is increased proportionally to the number of cleaning times. Leakage current is in the range of 1×10-¹∼1×10(-8)[A] according to the cleaning times, especially, we notice that additional RCA cleaning increases the leakage current in the order of hundred times compared to one times cleaning under 10[V] gate voltage. The electrical breakdown field using the breakdown obtained by I-V method is in the range of 8~12[MV/cm]. This measure is decreased proportionally to the cleaning times. This increment of leakage current by additional RCA cleaning result in the 0.8% decrement of yield. Since cleaning process of before gate oxidation directly affect the device performance and reliability, we think that further investigation is necessary for the clear understanding and of cleaning process.

조선시대 궁중가례와 화장에 관한 연구

이정원,이정민 한국메이크업디자인학회 2007 한국메이크업디자인학회지 Vol.3 No.3

This study is about the wedding feast and make-up of royal court at Joseon dynasty era. Joseon dynasty era is not only the most active era in are as such as culture. ideology and art. but also the era when the modem style of traditional Korean costumes is established. 'Gungjung Garae' is the wedding feast of a king who represents a country, and a cultural asset which represents the ceremonies and costume of Joseon dynasty era. In this study, the process, costume and make-up of the wedding feast of royal court are surveyed, and books and prior studies about these have been referred to for this study. First, Joseon dynasty announces a command which prohibits people from being married for a while. Then the candidates for the queen are selected by the first, second and third evaluation processes. Then, in the process of the wedding feast are Napchae, Napjing, Gogi, Chaekbi, Bong young and Dongroe. Second, for the main ceremony of the wedding feast, the king puts on the imperial crown and a black-colored costume called as Myonbok which is composed of Jungdan, Sang, Eui, Daedae, Pyesuel, Hyukdae. Paeok, Soo, Mal, Suk, Cyoo, and Bang-sim-gok-ryoung. The queen puts on a red-colored costume which is embroidered by pheasant, and composed of Jungdan, Hapi, Naeui. Sang, Pyesuel, Daedae, Hyukdae, Paeok, Soo, Mal, Suk and Gyoo. Third, as the queen's make-up for the main ceremony, her face is made up and painted with face powder and Yeonji, and this process is called as 'Sungieok' in Joseon dyanasty era. The A shaped hair style at the feast is called as 'Daesu meori' on top of Jjokrmmmeori and decorated with sevearl yongbinyuoe(dragon shaped ornamental hairpins ), Ddeol-jam and many accessories. The objective of this study is that the results of this study contribute to the inducement of more interests to Korean tradition and culture, and the development and inheritance of our tradition with pride.

산국 (Chrysanthemum boreale) 휘발성 추출액의 항균 및 항진균활성

차정단,김태영,우원홍,정규용,김강주,길봉섭 원광대학교 생체재료·매식연구소 1999 원광생체재료·매식 Vol.8 No.1

To investigate the antimicrobial and antifungal activity of Chrysanthemum boreale(C. boreale) essential oil, the growth inhibition against Aspergillus nidulans, Fusarium oxysporum, Alternaria mali, Staphylococcus aureus, Streotococcus pyogenes, Streptococcus mutans and Escherichia coli in the presence of the essental oil was monitored by agar dilution method. The antifungal effect of C. boreale on Aspergillus nidulans, Fusarium oxysporum and Alternaria mali as affected at the concentration of 400 ppm. The antibacterial effect of C. boreale on staphylococcus aureus, streptococcus pyogenes and Streptococcus mutans was affected at the concentration of 0.4 μl, while growth of E. coli was not inhibited at the concentration of essential oil. The results of this experiment on microorganisms indicated that naturally occuring chemical substances from C. boreale might have biologically toxic activities, that is, allelopathic potentials to the microorganisms.

Beta-차단제와 Hydrochlorothiazide 倂用에 依한 본태성 고혈압 환자의 血淸脂質에 미치는 效果

金善政,李宗經,劉元相 인제대학교 1984 仁濟醫學 Vol.5 No.4

Serial changes of serum lipids were observed in 54 patients with essential hypertension, administered several beta-blockers (e.g. acebatolol 400mg, atenolol 50mg, pindolol 10mg, propranolol 160mg, respectiviely) combined with hydrochlorothiazide 25mg for up to 12 weeks. The results were as follows: 1.The blood pressure was normalized at 12 weeks except propranolol group. 2.Seroum total cholesterol was decreased to 11% in both pindolol group and propranolol group, and not remarkable in other groups. 3.Triglyceride was decreased in propranolol group to 50% at 6week and 12 weeks, and not remarkable in other groups. 4.HDL-Cholesterol was decreased from 5% to 20%, most remarkable in propranolo group and decreased in pindolol group to 5% only. 5.Cholesterol ratio was increased only in pindolol group to 4.5% and decreased from 5% to 10% in other groups. In summary, these mild changes of serum lipid profiles alarm the physicians to check serum lipids before and during medication, especially in youger hypertensive and hyperlipidemic patient.

탄소/에폭시 복합재판의 압축강도 두께효과에 대한 연구

이정환,공창덕,오경원,Soutis, C. 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.1

본 연구에서 복합재료의 압축강도에 대한 두께 효과가 〔0₄〕ns,〔45/0/-45/90〕ns and 〔45n/0n/-45n/90n〕s (n = 2 to 8)등의 적층방법을 이용하여 체계적인 실험을 통해 조사되었다. 엇교차 대칭 복합재판의 파괴강도에 대한 적층순서효과도 조사되었다. 이를 위해 2종류의 다른 스케일링을 갖는 (1) 플라이레벨 기법인 〔45n/0n/-45n/90n〕s과 (2)서브라미네이트-레벨기법인 〔45/0/-45/90〕ns가 적용되었다. 일방향 적층시편 〔0₄〕ns과 플라이레벨인 〔45n/0n/-45n/90n〕s에는 분명한 두께효과를 나타내었다. 그러나 서브라미네이트레벨인. 〔45/0/-45/90〕ns의 압축강도는 시편의 두께의 변화에도 불구하고 별 영향을 나타 나지 않았으며,서브라미네이트-레벨 시편에서 구한강도가 플라이-레벨 시편에서 구한 강도보다 약간 높았다. 측정된 파괴강도는 예측 값과 비교되었다. In this study, the effect of laminate thickness on the compressive behaviour of composite materials was investigated through systematic experimental work using the stacking sequences, 〔0₄〕ns, 〔45/0/-45/90〕ns and 〔45n/0n/-45n/90n〕 s (n = 2 to 8). The stacking sequence effects on failure strength of multidirectional laminates were examined. For this purpose, two different scaling techniques were used: (1) ply-level technique 〔45n/0n/-45n/90n〕s and (2) sublaminate level technique [45/0/-45/90]ns. An apparent thickness effect existed in the lay-up with blocked plies, i.e. unidirectional specimens ([0₄]ns) and ply-level scaled multidirectional specimens (〔45n/0n/-45n/90n〕s). From the investigation of the stacking sequence effect, the strength values obtained from the sublaminate level scaled specimens were slightly higher than those obtained from the ply level scaled specimens. The measured failure strengths were compared with the predicted values.

산불 피해 소나무재의 역학적 특성 및 급속오븐 건조특성

황원중,권구중,박종수,김남훈 한국목재공학회 2003 목재공학 Vol.31 No.4

본 연구에서는 산불 피해 소나무재의 이용을 위한 기초자료를 얻고자 역학적 및 건조 특성을 조사하였다. 산불피해재는 종압축 특성, 전단강도, 충격휨흡수에너지 등에서 건전재와 거의 유사한 결과를 보여주었으며, 산불피해재 변재부의 휨특성은 건전재보다 양호하게 나타났다. 건전재와 산불피해재 변재부의 생재함수율은 산불피해재가 다소 낮았으나, 건조속도는 거의 차이가 없었다. 건조시 발생되는 초기할렬은 건전재가 산불피해재보다 발생율이 높았고, 내부할렬은 건전재와 산불피해재에서 발생되지 않았다. 따라서 산불에 의해 피해를 입은 목재의 대부분은 수피부를 제거하여 이용할 경우 건전재와 거의 동일한 용도로서 사용이 가능할 것으로 생각된다. The Mechanical and drying characteristics of Pinus densiflora wood, which was damaged by forest fire, and sound wood were examined. There were no significant differences in axial compressive properties, shearing strength and impact bending absorbed energy between damaged and sound woods. But the bending properties of damaged wood were slightly higher than those of sound wood. The green moisture content of sapwood in damaged wood was lower than that in sound wood, but oven-drying rate was similar in both woods. Number of initial check in damaged wood was smaller than that in sound wood, and inner check in damaged and sound woods was not observed. Consequently, it is considered that mostly damaged wood by forest fire can be used for wood material after removing the considered that mostly damaged wood by forest fire can be used for wood material after removing the bark.

아동의 구강보건에 대한 보호자의 관리태도 및 지식정도에 관한 조사연구

양정강,이원용 大韓小兒齒科學會 1975 大韓小兒齒科學會誌 Vol.2 No.1

The study was performed to evaluate the Parent's knowledge and attitudes concerning the dental health of their children. A questionnaire consisting of 17 questions was given to each of the 664 parents by their children who are attending in primary school and was completely by them. The collected information from the questionnaire was analyzed by the visits to dental clinic, age and education. The results obtained from this study are as follows: 1) The more educated parents were more interested to the dental health of children. 2) In the knowledge concerning the dental health of their children, the parents who were more educated and had visited the dental clinic gave the better responses. 3) There were no clear differences in age groups in the knowledge and attitudes on their children's dental health. 4) The reason for first visiting the dental clinic was dental treatment 43.2%, toothache 35.4%, for the purpose of oral examination 21.2%, and others were 9.2%. 5) 13.1% of the parents who had visited the dental clinic couldn't or didn't follow the recommended treatment because of economic difficulty 53.3%, lack of time 25%, lack of understanding of child's dental needs 18.3%, and other reasons were 3.3%.