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        • 태안반도 산촌형성요인에 관한연구

          이봉준 서울대학교 지리교육과 1977 지리학과 지리교육 Vol.7 No.1

          The aim of this study is to clarify regional characteristics by examining various factors having developed dispersed pattern of settlements on the Tae-An Peninsula, Choong Cheung Province. For the purpose of this study, intensive bibliographical studies of data concerned with this area were done and used actual field work. Results of this study may be summarized: (1) Tae-An peninsular, which belongs to Choongcheung Nam-Do and is bordered with the Gyeon gi Bay, has not been closely connected with the central area of the Gyeunggi Province for a long time. About 79% of the peninsula is made up of low mountains and hills. Plains and rivers are poorly developed, arable lands do not extend continuously in the peninsula. Ground water level is comparatively high and the entire land is well-drained. These physical characteristics supply foundations for the development of dispersed settlements. (2) Tae-An peninsular is one of places which have long been inhabited by men. For .a long time in its history, this peninsula was quite important for water transportation. In particular, in the Koryo and the Yi-Dynasties it was considered as a place of much importance on account of its water transportation of taxation rice. There were in this peninsula two attempts of constructing a canal accross it. (3) To defend the peninsula from the invasions of the Japanese pirate raiders and preserve human lives and properties, the inhabitants of this peninsula formed military villages and other villages surrounded with walls. At the end of the Koryo Dynasty, however, frequent invasions of the Japanese raiders forced the villagers to move to some .other places. The settlements which had been developed in the pre-historical era was since then devastated. (4) At the beginning of the Yi Dynasty these settlements were redeveloped. Since the majority of the villagers originally inhabited in this peninsula had moved to other regions, others who came into this peninsula formed new settlements. In addition to the common men who moved to this peninsula many noble men rusticated here from Seoul. These flows of population caused the number of population in this peninsula to increase with the result of maintaining. the lineage of the family. (5) It is estimated that tie dispersed villages of this peninsula were generally formed in the early Yi Dynasty. The villagers were for the most part composed of rusticated people and others flowed into this peninsula and villages had comparatively broad arable lands. These dispersed villages still remain almost as they were in the past. As suggested above, the development of these dispersed villages was not due to one single. factor, but to various factors such as the physical features, population outflows and inflows, the mode of choosing places for inhabitation in accordance with the theory of Poong-Soo, the relationship between the nobility and the common people, and tenant farming. These dispersed villages involve some factors which may interfere with the New Country Movement. For example, the difficulty incooperation between or among villages and in suppling electricity to all the villages. Besides, this peninsula is geographically vulnerable to the North Korean invasion: This is why the Government intends to bring together the small villages into larger ones. It is expected therefore that the traditionally dispersed villages in this peninsula will be grouped in the near future.

        • 低速 Airfoil에서 境界層에 依한 功力係數의 變化에 關한 硏究

          李奉俊 한국항공대학교 1975 論文集 Vol.8 No.-

          Mach 數가 작은 Airfoil에서 境界層에 의한 空力係數의 變化를 다음과 같이 5단계로 구분하여 계산하였다. 1)層流境界層을 Thwaite 方法에 依해서 計算했고 2)Schlichting & Ulrich 曲線에 依해서 lower critical 點을 推定하고 3)Schlichting 곡선에 依한 遷移漸의 예측 4)Head 의 方法에 依한 亂流境界層의 計算 5)Squire 와 Young 의 關係式에 依한 Wake 의 計算을 하므로서 境界層에 依한 空力係數의 變化를 구하였다. 本 論文에서 Airfoil의 空力係數를 計算하기 爲하여 遷移點의 결정에 앞서 lower critical point를 먼저 구하였다. 뒤에 理論値와 實驗置를 비교하기 爲하여 NACA 23012 Airfoil의 수직空力成分을 여러가지 맏음각에 對하여 구하고 實驗置와 比較하였다. A method for calculating the aerodynamic coefficient of airfoils at low Mach number is studied. Study is based on 1)calculation of lamiar boundary layer by Thwite's method 2)prediction of lower critical point by Schlichtint & Ulrich curve 3)prediction of transition point by Schlichting curve 4)calculation of turbulent boundary layer by Head's method and 5)calculation of wake by means of the Squire & Young relation. In this study the prediction of lower critical point was done first, then predicts transition point for calculating the aerodynamic coefficient. Normal aerodynamic component has been calculated by this method for NACA 23012 airfoil at various angle of attack. Comparison of the results wkth NACA experimental data shows a good agreement.

        • 낮은 레이놀즈수에서 三角 윙�꼭�있는 날개의 特性

          李奉俊 한국항공대학교 1987 論文集 Vol.25 No.-

          Three dimensional wing produces an induced drag. Many studies have been made to reduce the induced drag and to increase the lift-drag ratio by properly controlling the vortex at a wing tip. It has been reported that the device, such as delta winglet, which is small, cambered and delta shaped wing like surface are remarkably effective for reducing the induced drag of a wing. A wind tunnel investigation has been conducted to determine the effect of delta winglet on the lift and drag characteristics of an aspect ratio 5 wing, wortmann FX-63-137 airfoil, unswept wing at low Reynolds numbers of 200,000. The results indicate that the delta winglet provided the basic wing with an increase in the lift curve slope, a reduction in the induced drag, and an increase in lift-drag ratio.

        • Trailing Vortex의 減衰에 關한 硏究

          李奉俊 단국대학교 대학원 1980 學術論叢 Vol.4 No.-

          A wing moving through a fluid induces a differential pressure field between the upper and lower surfaces. The resultant spanwise movement of fluid combined with the free stream velocity generates a helical movement of fluid about the wing tip called trailing vortex. The induced drag of the wing is caused by this trailing vortex. This paper deals with an experimental results to decay such a trailing vortex int he recent years. The purpose of this investigation was to determined the effect of the wing geometry to decay a vortex in vortex flow such as propeller slip stream. The experimental investigation utilize a small vorticity meter to measure the vorticity strength behind the wing tip. The investigation considers the aspect ratio and taper ratio of the wing as a parameter that affect the strength of the trailing vortex. The following conclusions can be drawn. (1) The vorticity of the trailing vortex can be reduced to 0.5 by fitting a small wing in vortex flow line at the incidence angle of 10 detrees. (2) The vortex decay by the geometry of the wing are as follows. (3) The vorticity decrease with increasing aspect ratio and have its maximum value at A.R=4. (4) The vorticity of the trailing vortex decrease with increasing taper ratio.

        • KCI등재후보

          初等學校 施設·設備 改善에 關한 硏究

          李鳳濬 韓國實科敎育硏究學會 1997 實科敎育硏究 Vol.3 No.1

          Since the school facilities which support the student learning such as the library, audiovisual room, etc. are characterized with a characteristic of common use in the aspect that total students or school staff use them in common, and such facilities play even as a place where guidance in life and useful information can be acquired and exchanged other than the activities related the curriculum, they should be so arranged that it is proper and functional for the students to perform activities and learn something there. Instead, it is a reality that such important facilities and equipments lack and are poor, and regardless of the user's demand of education, they take spaces in schools and are arranged disorderly. Therefore, this study was motivated from the necessity for the effect of education by the school's facilities and equipments to be uplifted.

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