가속도계를 이용한 재료의 영계수 측정방법

손창호(Sohn, Chang-Ho),박진호(Park, Jin-Ho),윤두병(Yoon, Doo-Byung),정의필(Chong, Ui-Pil),최영철(Choi, Young-Chul) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.11

For the description of the elastic properties of linear objects a convenient parameter is the ratio of the stress to the strain, a parameter called the Young's modulus of the material. Young's modulus can be used to predict the elongation or compression of an object as long as the stress is less than the yield strength of the material. Conventional method for estimating Young's modulus measured the ratio of stress to corresponding strain below the proportional limit of a material using a tensile testing machine. But the method needs precision specimens and expensive equipment. In this paper, we proposed method for estimating Young's modulus using accelerometer. The basic idea comes from that the wave velocity is different as the Young's modulus. To obtain Young's modulus, a group velocity is obtained. It is difficult to measure group velocity. This is because plate medium has a dispersive characteristics which has different wave speed as frequency. In this paper, we used Wigner-Ville distribution to measure group velocity. To verify the proposed method, steel and acryl plate experiments have been performed. Experimental results show that the proposed method is powerful for estimating Young's modulus.

전도도법에 의한 치환 피리딘들의 해리상수 측정과 그의 온도와 압력에 따른 영향

黃正儀,鄭倧在,金學成,尹永炷,朴義煥 慶北大學校 物理化學硏究所 1985 硏究論文集 Vol.6 No.-

Generally, pyridine and most of substituted pyridines act as base in aqueous solutions. The strengths of their basicities can be expressed quantitatively by the dissociation constant of base or its conjugated acid. Generally, the acidity of substituted pyridines can be expressed by K_a of the following reaction. ◁그림삽입▷(원문을 참조하세요) The dissociation constants of these subtituted pyridines have not been reported under high pressure but under atmospheric pressure. In this papers, the dissociation constants of some substituted pyridines were measured under high pressure by the conductometry. From the ionic conductivity of hydrogen ion, the dissociation constants(K_a) were calculated. The K_a values were increased with increasing temperature and were decreased with increasing pressure. The characteristics of dissociation process of some substituted pyridines were deduced from the thermodynamic properties calculated from the dissociation constants.

전치부의 발육 결함 및 교정 후 탈회 병소의 심미적 개선을 위한 resin infiItration

김은영,안울진,김신,정태성 大韓小兒齒科學會 2010 大韓小兒齒科學會誌 Vol.37 No.2

어린이 영구전치의 법랑칠 발육 결함이나 고정성 장치에 의한 교정치료 후 탈회 병소는 흔히 심미적 문제를 유발한다. 본 연구는 상악 전치부에 위 원인에 의한 탈회로 인하여 백반양 병소를 보이는 21명 어린이의 38개 치아를 대상으로, 최근 비침습적인 방법으로 소개된 resin infiltration 기법을 적용하고, 병소의 색조의 임상적 개선 효과를 비교, 분석하여 다음과 같은 결과를 얻었다. 1. 1주 후 색조가 개선된 병소는 발육 결함 병소의 25%, 교정 탈회 병소의 61%로 나타났다. 2. 발육 결함 병소의 40%, 교정치료 후 탈회 병소의 6%에서는 시술 전후의 색조변화를 관찰할 수 없었다. 3. 법랑질 발육결함 병소에서는 시술 직후 보다 1주 후에 더 많은 색조 변화를 관찰할 수 있었다. 결과적으로 일부 증례에서는 색조의 극적인 개선이 관찰되었으나, 또 일부 증례에서는 변화가 거의 나타나지 않았는데, 이는 병소 깊이의 차이에 기인한 것으로 사료되었다. The prevalence of developmental defects of enamel and lesios by post-orthodontic decalcification has been reported with increasing frequency. Even though there have been increasing interests and clinical challenges in esthetic improvement of these lesions, few of studies were reported for using non-invasive approach which is a very significant matter for child and young adults. This study was conducted to assess clinical effect on the improvement in color of these lesions via resin infiltration method developed as minimum invasive technique for white spot. For the 38 maxillary anterior teeth with calcification problem. the changes in color between before- and after- infiltration treatment, were evaluated and summarized as following. 1. A week after infiltration, 25% of developmental defects and 61% of decalcification lesions were improved in color as the value of ΔE below 3.7. 2. 40% of the developmental defects and 6% of decalcification lesions showed no significant change. 3. The developmental defects showed more remarkable changes in color 1 week after infiltration rather than immediately after the treatment. From our study results, it is considered that the amount of color improvement depended on the depth of lesion. In other words, for the lesion having more depth than the depth infiltrant resin can penetrate into, infiltration treatment showed no significant effect. Therefore, for clinical indication of resin infiltration treatment, further research on precise measurement technique of lesion depth is strongly required.

분광광도법에 의한 3-Chloro 및 3-Bromopyridine의 해리상수 측정과 그의 온도와 압력에 따른 영향

黃正儀,鄭倧在,尹永炷,金學成 慶北大學校 1984 論文集 Vol.38 No.-

Pyridine and most of substituted pyridines react as base in aqueous solutions. Strength of their basicities can be represented quantitatively by the dissociation constant of a base or its conjugated acid. The dissociation constants of weak acid or base are highly dependent on the pressure and the temperature. The dissociation constants of these substituted pyridines have been reported only under the pressure of atmosphere but not high pressure. In this study, we measured the dissociation constants of 3-chloro and 3-bromopyridine under high pressure by the method of spectrophotometry. Also, we obtained the thermodynamic parameters on the dissociation reactions that show the effects of the temperature and the pressure on the dissociation constants.

고층건물의 벽면조경기법에 관한 연구

李英武,李松宜 홍익대학교환경개발연구원 2001 환경개발연구논문집 Vol.6 No.-

The purpose of this study is to consider the importance as well as the various techniques of landscaping the wall of architecture, and to examine the characteristics of the plants used on landscaping the wall of high rise buildings and present appropriate applicable techniques. Modern urban development was considered as a monument of mankind's volition and technology although it brought destruction of the natural environment. However the adverse reactions have gradually been perceived and now the importance of nature has been acknowledged. These days, for the expansion of urban green space, the restoration of the urban ecosystem and the normalization of abnormal climates in the city (the heat-island phenomenon, urban floods, exhaustion of underground water etc.) new attempts such as indoor gardens or rooftop gardens, wall surface landscapes etc. have come up rapidly. Many papers and studies related to this have been published. Especially due to the high-rise and highly dense structure of today's cities the effectiveness of wall surface landscaping has become increasingly highlighted. The techniques of landscaping the wall of high rise buildings improve the urban ecosystem and scenery while also creating amenity in urban spaces by providing habitats for insects and birds by screening the exterior of the desolate modern city with natural green life. Also by reducing radiation from the surface of buildings it helps control abnormal city climates such as the heat island phenomenon etc. and by reducing the change of surface temperature it cuts down on the energy of the whole city. Beside this it also protects the surface of the architecture and strengthens the structure as well as reducing air pollutions by expanding green space. Landscaping wall techniques ultimately provide citizens with a sense of security both mentally and emotionally, bringing vigor into the city. Although, as seen above, landscaping wall techniques can bring life into urban space in many ways, these have not been progressively inducted into present domestic landscape architecture. It is still being empirically applied, therefore presenting many limits to the expansion of new urban forest. This paper tries to cast a light to a new horizon.

상아질 표면 처리 방법에 따른 Compomer의 전단 결합 강도

오영학,홍찬의 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.2

The purpose of this study was to evaluate the shear bond strength of compomers according to dentin surface treatment. Two materials of compomer were devided into six groups. The compomer used in this study were Dyract AP(D) and F2000(F). Group 1 (DN) and 4(FN) were treated according to manufacturers instructions as control groups. Group 2(DE) and 5(FE) were treased with 37% phosphoric acid and group 3(DA) and 6(FA) were treated with air abrasion unit (80 psi, 50 m aluminum oxide particles) respectively as experimental groups. After dentin surface treatment, compomers were bonded. Completed samples were stored in 100 % humidity, 37C during 7 days. and then, the shear bond strength of specimens were evaluated. The results were as follows : 1.In the case of Dyract AP, the shear bond strength was showed the highest value of 9.10 MPa in dentin surface treatment with air abrasion unit, but there were no significant differences to the other groups. 2.In the case of F2000, the shear bond strength was showed the highest value of 13.51MPa and there were significant differences to the other groups (p<0.05). 3.The shear bond strength of F2000 was higher than Dyract AP in each dentin surface treatment, and in the case of etching and air abrasion, there were significant differences(p<0.05). 4.As a result of observation of SEM, the most of fracture pattern was adhesive failure in group 1(DN), 2(DE) and 4(FN), and cohesive failure in group 3(DA), 5(FE) and 6(FA).

테르펜과 1,2-디메틸싸이클로펜텐의 기체상 오존화반응

윤의중,구본석,정인수,정인찬,이영훈,신혜숙 한서대학교 산학협력연구원 부설 환경연구소 2000 환경연구소 논문집 Vol.3 No.-

Gas phase Ozonolyses have been examined with particular emphasis on the question whether are produced. The following results were obtained. 1) In contrast to previous reports, Ozonolyses of the terpense β-pinene and sabinene provided the corresponding ozonides as minor products. Major products were the corresponding ketones, respectively. In addition, β-pinene afforded the lactones, while sabinene gave the lactones. 2) Ozonolyses of 1, 2-dimethylcyclopentene provided the corresponding ozonide as a minor and diketone as the major product, along with small proportions, each, of nine additional products. 3) Ozone treatment of diketone provided small amounts of Ozonide in a hitherto unprecedented reaction of diketiones with ozone.

청소년의 일탈행동 무경험 집단과 경험집단의 환경, 심리, 행동 특성의 차이 분석

김영희,박영신,김의철 한국아동교육학회 2004 아동교육 Vol.13 No.2

이 연구에서는 청소년 일탈행동 경험집단과 무경험집단의 환경 및 심리 행동특성의 차이에 대해 분석하였다. 초등학교 6학년 1,012명은 표집하였고, 동일한 학생들이 중학교 1학년이 되었을 때 846명을 계속 표집하여 동일한 분석을 하였다. 분석 결과, 초등학교 6학년 경우, 일탈행동 경험집단이 자기조절학습효능감과 자기조절동기효능감은 낮았으나, 스트레스는 더 높았다. 또한 학업성적도 훨씬 낮았다. 중학교 1학년 시기에는, 일탈행동 경험집단이 부모로부터 정서적 지원은 적게 받고, 부모의 양육태도는 더욱 적대적 거부적 무관심 갈등적인 것으로 확인되었다. 그리고 교사와도 갈등이 더 많았다. 심리특성의 면에서는 일탈행동 경험집단이 더 낮은 관계효능감을 나타내었다. This study examines the environmental, psychological, and behavioral factors that influence delinquency among Korean adolescents. A total 1,012 adolescents participated in the study when they were Grade 6 students. When they reached Grade 7, a total of 846 completed survey in the follow-up study. In the first phase, those adolescents who had lower scores on self-efficacy for self-regulated learning and self-regulatory efficacy were more likely to engage in delinquent behavior. Adolescents engaged in delinquent behavior reported higher levels of stress and had a lower academic grade. In Grade 7, those adolescents who received less emotional support from their parents, perceived greater hostility, rejection, neglect and conflict with their parents, and experienced greater conflict with their teachers were more likely to engage in delinquent behavior. Those adolescents who had lower scores on relational self-efficacy were more likely to engage in delinquent behavior.

소프트웨어 콤포넌트 재사용 프로세스 지원을 위한 도구

문의영,김태공,서재현 인제대학교 1999 仁濟論叢 Vol.15 No.1

소프트웨어 개발 위기의 원천은, 갈수록 소프트웨어가 비대해지고 있다는 데 있다. 소프트웨어의 개발자들은 새로운 버전이 개발할 때마다 관련된 새로운 기능들을 가능한한 많이 추가한다. 이 기능을 모두 이용하는 사용자는 극히 드물다. 이로인해 재사용의 중요성이 부각되면서 객체지향 기술을 보완 할 수 있는 컴포넌트와 관련된 연구가 활발히 진행되고 있다. 컴포넌트는 다양한 정의가 존재하지만, 대체로 재사용 가능하며 의미있는 동작을 지닌 객체나 그러한 객체의 모임' 이라고 정의할 수 있다. 본 논문에서는 재사용을 지원하는 방법에 관해 논하였다. 소프트웨어 재사용 기술은 재사용 가능한 자원을 만들거나 사용하는 과정 자체에 관한 연구와 이를 지원하는 도구나 기법을 연구하는 부분으로 나뉘어 지는데 여기서는 재사용 프로세스를 지원하는 tool에 중점을 두었다. The cause of software development crisis that because lager and lager. Development of program add many relative functions to it whenever they develop a new version. Few users use these function. For this point of view, a reusability and supplying object-oriented technique, the study related with component is processing actively. The component has many definitions, however it is defined that generally, 'objects or the set of objects with reuseable and meaning action'. In this paper, we describe methodology of supporting reusability. Software reuseable technique is deviled two fields. One is the study processing of making and reuseable resource, another is that of tool or technique for this. We will mention the tool for supporting reuseable process later.

에이전트를 이용한 WWW상의 가상 개별 교수시스템 설계

문의영,서재현,김태공 인제대학교 1999 仁濟論叢 Vol.15 No.1

최근 교수-학습환경이 시공간을 벗어나 가상공간에서 대두 되고있는 가상 학습을 통해 학습자 중심의 원격교육 환경으로 급속히 변천해 가고 있다. 하지만, 대체적으로 교육 시스템은 단순히 단방향적인 일관된 정보전달과 수동적인 학습을 통해 정보주입식 교육이기 때문에 보다 지능적이고 효과적인 학습자중심의 상호작용의 정보를 주고 받으면서 개개의 학습능력에 적합한 교육을 시행함으로써 이에 학습자는 보다 능동적으로 정보를 습득해 자신의 정보로 만들수 있는 교수 시스템을 요구하기에 이르렀다. 본 논문은 이러한 효율적이고 학습자 중심의 교수 시스템을 위해 상호정보 교류역할을 하는 에이전트를 두어 유연성 있는 가상 교수 시스템을 설계하는데 중점을 두었다. Recently, tutoring-learning enviromment is changing rapidly. The learner-centered remote education system with cyber study appeared in caber space beyond space-time. However, generally, because the current education system is the information cramming system which is consistent information transmission and passive learning, learners need the tutoring system that make him to take his information actively. This requires the suitable teaching with individual ability, giving and taking more intelligent and effective leaner-centered information. For this efficient leaner-centered tutoring system, in this paper, we design a flexible cyber tutoring system with the agent fo information interchange for each other.