20~30대 젊은 여성의 골밀도, 신체조성과 식행동 연구

구재옥,안홍석,유숙영 대한지역사회영양학회 2008 대한지역사회영양학회지 Vol.13 No.4

This study was carried out to identify bone mineral density (BMD), body composition, lifestyle and dietary habits of young women by physical measurement and questionnaires. The study subjects, 190 young women living in Seoul, were divided into three age groups: 20 ~ 24 years (93), 25 ~ 29 years (44) and 30 ~ 39 years (53). There was no significant difference in mean body muscle mass, protein, mineral, body fat and BMI among the three age groups. The rate of low weight (18%) in 20 years group was higher that of the 30 years (11.3%). The mean BMD and T-score were 0.44 g/㎠ and -0.66. BMD and T-score of the forearm bone were significantly higher in the 30 ~ 39 years group. But BMD and T-score of calcanues were not significantly different among the three age groups. The rate of normal, osteopenia and osteoporosis subjects by BMD were 60.5%, 38.4%, 1.1%, respectively. The rate of osteopenia in 20 ~ 24 years group was significantly higher than the other age groups. The rate of meal irregularity was significantly higher in 20 ~ 24 years group. The rate of women who walk and are exposed to sunlight more than 1hr per day were significantly higher in 20~24 years group than the others. However, the score of food behaviors is significantly higher (bad) in 20 ~ 24 years group than the others. The relationship between BMD and frequency of food intake showed significant differences in beans, broom, seaweed and rice wine. In conclusion, the risk rate of BMD was very high, 40% of the subjects, and the risk rate of BMD was higher in 20 years group than 30 years group, and the rate of low weight in 20 years group was higher than in 30 years group. The food habits and behaviors were not healthy enough. Therefore, nutrition education is needed for bone health.

공침법으로 제조한 Y-TZP(+10m/o Al₂O₃)에서 미세구조가 기계적 성질에 미치는 영향

구자호,이홍림 연세대학교 산업기술연구소 1991 논문집 Vol.23 No.2

ZrO_2(+3m/o Y_2O_3)-10m/o Al_2O_3 and ZrO_2(+3m/o Y_2O_3)-5m/o Al_2O_3 powders were synthesized by coprecipitation method using ZrOCl_2・8H_2O and YCl_3・6H_2O, Al_2(SO_4)_3・18H_2O as starting materials. Studied were the sintering behavio of Y-TZP ceramics with temperatures(1200~1600℃) and the changes of mechanical properties with microstrucutres. Relative densities of sintered bodies were >95% above at 1400℃. Especially, in the case of ZY10A600, it shows 96% R.D. at 1200℃ and 98% R.D. at 1300℃. All sintered bodies were consisted of tetragonal ZrO_2 and α-Al_2O_3 phases. Maximum mechanical properties were as follows; K_IC=12.3 MPa・m^1/2, Hv=14.6 GPA. And when ZY5A+5A-800 was sintered at 1500℃, it was infered that the sintered body had the mechanical properties and microstructure of nanocomposite ceramics.

수직적 안모형태와 치아성숙도의 상관관계에 대한 연구

구용한,현홍근,김정욱,장기택,이상훈,한세현,김종철 大韓小兒齒科學會 2010 大韓小兒齒科學會誌 Vol.37 No.1

본 연구는 수직적 안모형태와 치아성숙도의 관계를 평가하고 이러한 연관성에 대한 사춘기 성장의 영향을 평가하기 위한 것이다. 이번 연구를 위해 7세에서 9세, 13세에서 15세 환자 1306명을 Ricketts의 VERT index를 이용하여 수직적 안모 형태를 분류하였고 환자들의 치령을 Demirjian법으로 평가하여 다음과 같은 결과를 얻었다. 1. 모든 군에서 치령이 역령과 비교 시 통계적으로 유의한 수준에서 크게 측정되었다. 2. 사춘기 연령군에서 brachyfacial type의 경우가 dolichofacial type 보다 치아성숙도가 크게 나타나는 경향을 보였다. 여성의 경우는 통계적으로 유의성있게 차이가 나타났으며, 남성의 경우는 통계적 유의성은 보이지 않았다. 3. Brachyfacial type의 경우 사춘기전 군들과 비교 시 사춘기 군들에서 치아성숙도가 유의성있게 높게 나타났으며, dolichofacial type의 경우는 연령층간 치아성숙도의 차이를 보이지 않았다. The purpose of this investigation was to study the relationship between vertical facial pattern and dental maturation in children in pubertal and pre-pubertal periods. The material consisted of lateral head films and panoramic radiographs of 1306 patients. The subjects were selected according to Ricketts's VERT index and other including criteria. These subjects were divided by VERT index to brachyfacial group and dolichofacial group. In each selected subject, dental age was determined according to Demirjian's dental maturity score. All subjects were distributed according to age, vertical facial type and sex, mean and standard deviation of chronological age, dental age and age difference were determined in each group. And the data were analysed to find the difference of tooth maturation by facial pattern. Findings of this study include: 1. In all groups, dental age was determined higher than chronological age in statistically significant level. 2. Compared by vertical facial pattern, in pubertal age groups, it seems that subjects with brachyfacial type presented the tendency to have an advanced dental maturation, only in female group. 3. Compared by pubertal period, brachyfacial groups presented more advanced dental maturation in pubertal groups than pre-pubertal groups.

서울대학교치과병원 소아치과를 내원한 교정환자의 분포양상에 대한 연구

구용한,현홍근,김정욱,장기택,이상훈,한세현,김종철 大韓小兒齒科學會 2009 大韓小兒齒科學會誌 Vol.36 No.4

과거에 비해 소아 및 청소년기에 교정치료를 시작하는 경우가 증가하고 있으며 따라서 소아치과에서 교정치료가 차지하는 비율 역시 증가하는 추세이다. 이러한 변화에 맞추어 소아치과에 내원하는 교정환자의 분포 양상을 파악하기 위하여 본 연구를 시행하였다. 2006년 1월부터 2008년 12월까지 서울대학교 치과병원 소아치과를 내원한 환자 중 교정 진단 받은 792명을 대상으로 조사를 진행하였으며 다음과 같은 결과를 얻었다. 1. 교정 진단을 받은 환자의 연령 분포는 8세가 22%로 가장 많았고 7세(19%), 9세(16%) 순서로 나타났다. 2. 골격 분포는 골격성 1급 부정교합이 52%로 가장 많았고 3급(29%), 2급(19%)순서로 나타났으며 연령이 낮은 경우 3급 부정교합 환자의 비율이 높은 경향을 보였다. 3. 총 792명의 환자 중 28%인 218명에서 전치부 반대교합을 보였으며 연령이 낮은 경우 그 비율이 높은 경향을 보였다. Distribution of orthodontic patients in pediatric dental clinics has increased recently. So it is worth to study about the present status of orthodontic patients in pediatric dental clinics. The purpose of this study was to recognize the characteristics and orthodontic patterns of orthodontic patients in pediatric dental clinics. The material consisted of distribution and orthodontic analysis records of 792 new patients in the department of pediatric dentistry, Seoul National University Dental Hospital, from 2006 to 2008. Results were as follows 1. In age distribution, 8-year-olds group comprised 22%, 7-year-olds 19%, 9-year-olds 16%, 10-year olds 15%, 11-year-olds 11%, and other age groups comprised 18%. 2. In skeletal patterns, skeletal class Ⅰ patients comprised 52%, class Ⅱ 29%, and class Ⅲ 19%. 3. In vertical facial types mesofacial comprised 41%, brachyfacial 35%, and dolichofacial 24%. 4. Out of 792 patients 218 patients(28%) showed anterior cross-bite, and the occurrence ratio of anterior cross-bite increased as the age decreased.

비정상 액체제트 분열 메카니즘

구자예,정홍철 한국항공대학교 1994 論文集 Vol.32 No.-

액적의 분열기구를 재조사하고 Rayleigh-Taylor불안정과 Kelvin-Helmholtz불안정 이론을 기초한 분열모델을 비정상 액체제트기둥에 적용하였다. 본 논문에서는 비정상 분열기구에 근거한 새로운 액체제트 분열모델을 개발하는 것이다. 액체 기둥은 연속된 액적구의 사슬로 생각되어지며 이 액체기둥은 제안된 분열기구의 불안정성 조건이 만족되는지를 계속 조사되어진다. 일단 액적구가 주 액체제트기둥에서 분리되면 이 액적들은 단일 액적분열이론을 적용 받는다. Bond수가 임계 Bond수 보다 높으면 단일 액적으로 생각되는 액적들은Rayleigh-Taylor불안정이나 Kelvin-Helmholtz불안정에 의해 계속 분열된다. 제안된 비정상 액체제트 분열모델을 사용하여 계산한 분무선단도달거리, 액적크기, 및 속도들의 분무특성은 실험에서 구한 이들 분무특성들과 비교하였다. The mechanisms of breakup of liquid drop are reviewed. A breakup model based on Rayleigh-Taylor instability and Kelvin-Helmholtz instability is applied to the transient liquid jet column. The focus of this paper is the development of a new liquid jet breakup model based on the transient breakup mechanism. Liquid column is considered as a chain of balls. Liquid jet column is continuously surveyed to apply breakup mechanisms. Once liquid droplets are separated from the main liquid jet column, these droplets are subjected to the single breakup mechanism. When Bond number is greater than critical Bond number, single droplets continue to break up by Rayleigh-Taylor instability or Kelvin-Helmholtz instability. Proposed models for transient liquid jet breakup were tested by comparing the calculated spray tip penetration and droplet sizes and velocities with the measurements.

농후 연료분무 측정시의 위상도플러 입자측정기의 평가

구자예,정홍철 한국항공대학교 1994 論文集 Vol.32 No.-

위상도플러간섭기술을 이용한 농후 연료 분무 측정이 제시되었다. 단일 구멍식 노즐에서 생성돈 농후연료 분무를 위상도플러 입자측정기(PDPA)를 사용하여 분무를 측정할때 여러 실험변수를 바꾸어 데이타의 적합성을 평가하였다. 농후분무를 측정하면 데이터 취득비율이 매우 낮기 때문에 실험데이터의 신뢰성에 의문이 생긴다. 따라서 이와 같은 조건에서의 문제점은 측정한 액적의 크기 및 속도 결과가 반복성이 있고, 실험변수에 의존적이지 않고, 실제분무를 나타냄을 확인하여야 한다. 최적 PMT전압과 천이주파수는 이들을 편화시켰을 때 체적유속 및 액적직경(크기)이 크게 변화하지 않는 곳에서 설정되어야 한다. 농후분무에서 데이터취득과 실험노이즈에 있어서 주파수천이의 영향은 미미하지만, PMT전압의 영향은 크므로 예비실험을 통하여 분무실 조건과 측정위치에 따라 적절하게 선정되어야 한다. The application of Phase Dopper interferometric techniques to the measurements of dense diesel fuel spray is demonstrated. An experimental investigation was conducted to evaluate the suitability of Phase Doppler Particle Analyzer (PDPA) for measuring dense fuel sprays produced by single hole nozzle. The critical issue is the use of PDPA for dense fuel spray is to insure the results from the drop size and velocity measurements is repeatable, consistent, and physically realistic because the validation rate of experimental data is very low due to the thick optical dense. The optimum photomultiplier tube (PMT) voltage and shift frequency should be chosen such that the data such as volume flux and drop diameter do not change rapidly. The effect of shift frequency is minor, however, the PMT votage setting is very sensitve to the data aquisition and noise in dense fuel spray.

벤처企業의 投資者保護를 위한 會社法上의 課題

禹興九,許悳會 건국대학교 법학연구소 2000 一鑑法學 Vol.5 No.-

The central task of corporation law is to protect minority shareholders. In public corporations, the problem is refered to as the separation of ownership and control. Managers, even those who own little stock, can comtrol public companies for their own benefit rather than striving to maximize shareholder wealth. Despite efforts of legislatures, and scholars to reform corporate law, the plight of minority shareholders persist. Managers of public companies remaun free to disdain shareholders, as evidenced by the deep discount from instrinsic value at which public stocks trade. In non-public, or close, corporations the issue is referred to as the opperssion of minority shareholders. Close corparations have no market for their stock, and they rarely pay dividends. Thus, minority shares are freguently worthless to hold and impossible to sell. these conditions discourage investment and prcipitate disruptive dispute in small companies. In the search for solutions, commentators have paid remarkalbe little attention to venture capitalist supplies equity financing, but does not assume control of the enterprise. A venture capitadist protets his investment through contracts. This provides a model for protecting minority investors in close corporations. Moreover, a venture capitalist's alility to supply major equity funding rivives that private financing could eclipse the public corporation. Finally, the Article demonstrates that venture capital confirms into the strength of private equity financing ; thus, venture capital has the potential to transform corporate finance. To fully realized this potential, however, the law must change to better accomondate monority investors.

企業의 社會的 責任과 株式會社法

禹洪九 건국대학교 행정대학원 1982 建國大學校 行政大學院 硏究論叢 Vol.10 No.-

비재무측정치를 활용한 전략실행의 전개

申洪哲,金京九 홍익대학교 경영연구소 2003 경영연구 Vol.28 No.-

美國法上 株主有限靑任原則의 再論

禹洪九 건국대학교 법학연구소 1996 一鑑法學 Vol.1 No.-

Limited liability is a fundamental principle and a distinguishing feature of corporation law.Limited liability means that the investors in the corporation are not liable for more than the amount they invest. Shareholders in the business corporation, that is to say, bear only the amount they invest in case of business failure and its bankruptcy. But, the rule of limited liability has never been absolutely limited. Courts in U.S.A.allow creditors to “pierce the corporate veil”, which means that stockholders msust satisfy creditors’claims. Therefore it is necessary to review limited liability in view of creditors’protection under the minimal capitalization. In connection. a writer examines the theories and cases in Japan, Germany and U.S.A. The function of limited liability is as follows. First, limited liability decreases the need to monitor. Second, limited liability reduces the costs of monitoring other shareholders. Third, by promoting free transfer of shares, limited liability gives managers incentives to act efficiently. Fourth, limited liability makes it possible for market prices to impound additional information about the value of firms. Fifth, limited liability allows more efficient diversification. Investors can minimize risk by owning a diversified portfolio of assets. Sixth, limited liability facilitates optimal investment decisions. In reality the firm must hold sufficient funds in order to manage business. That is to say, the lower a firm's capitalization, the higher the probability that it will engage in excessively risky business. It is a problem of limited liability. In case of undercapitalization the creditors of firm can't help taking risks. Therefore the method to reduce the cost of limited liability must be studied. To reduce the cost of limited liability, courts have adopted the doctrine of piercing the corporate veil. Other legal rules, such as mamagerial liability, minimum-capitalization requirements can also be understood as attempts to reduce the cost of limited liability. The system of this thesis is as follows. Ⅰ. Introduction Ⅱ. The history of limited liability in U.S.A. Ⅲ. Undercapitalization and a rule of limited liability Ⅳ. The argument for legal basis of limited liability Ⅴ. The share and risk of bankruptcy of firm Ⅵ. Undercapitalization and denial of limited liability Ⅶ. Review of limited liability Ⅷ. Conclusion