태양광 발전시스템을 위한 계통 연계형 PWM 인버터의 변조지연 보상

성낙규,한경희,강승욱,이승환,유택빈 明知大學校 産業技術硏究所 1995 産業技術硏究所論文集 Vol.14 No.-

Since the residential load is an AC load, while the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell and must provide the sinusoidal wave current and voltage, at unity power factor in the case of driving to interact with utility line. PWM modulator must do stable modulation even though it contains the disturbance like a distortion and noise, and it needs compensation method, because there is a timing interval between sampling points and carrier waves, while the synchronous signal is controlled by the micro processor. In this paper, we maximaze output of solar cells which is propotional to variation of insolation, using single phase PWM voltage source inverter, and we can drive in high power factor with utility line by control and compensation method which is concerned with synchronous signal distortion and modulation delay, using low pass filter and phase shifter.

機械加工品의 最適加工速度에 關한 硏究

成煥泰,吳澤烈,吳煥燮 慶熙大學校 1980 論文集 Vol.10 No.-

In this study, the optimum mathematical models were made in order to derive Optimum Machining speed which is due to be established in the production of each manufactures as an important parameter based upon the cutting speed, in case of making manufactures of multi-kinds into unit-production processing. The economical optimum cutting speed has been set up by using the above phenomenon as a proper system, and the results from the comparative analysis between the above model & the actual cutting work data, are summarized as follows. (1) The mathematical models for the optimum machining speed are derived into the expressions (23), (24), (25), (26), (27), (28), (29). (2) The basic expressions of the optimum machining speed are derived into (32), (34), (36), (37), (39), (40), (41), (44), for the purpose of each estimation of the maximum efficiency standard, the minimum cost standard and the maximum profits rate standard. (3) The example of setting up the optimum cutting speed of multi-kinds manufacturing production was formulated, and the experimental theoretical values were known to be in the same range as a result of the comparative study between the cutting speed obtained by the cutting test & the optimum cutting speed calculated by the theoretical expressions.

고압 다이버트 밸브 개발에 관한 연구

허성관,장영균,권택진 大邱大學校 科學技術硏究所 1998 科學技術硏究 Vol.5 No.3

Current industrial infrastructure has some drawbacks such that the effort for the efficiency of the facilities, most of which are imported, increase the cost of manufacturing. the special types of valves have been imported since the performance and the functional requirements are satisfied by the home products. Actually, the local products of the valve can be used only 1,000m Aq of lower pressure. On this paper, we develop the high pressure divert valve, which can be born the pressure of 3,000mm Aq. This development can contribute to the reduction of the cost and the increase of export.

Trifluoromethyl(CF_3)기를 함유한 폴리아미드의 합성과 물성에 관한 연구

배성호,이용택 경희대학교 산학협력기술연구원 2000 산학협력기술연구논문집 Vol.6 No.-

Trifluoromethyl containing polyimide(PI) was synthesised thermal and chemical imidization method. Increasing trifluoromethyl contents in polyimide main chain it appears increasing solubility and transmittance in visible region and decreasing thermal decomposition temperature. Chemical imidized PI has lower decomposition temperature than thermal imidized PI but did not affect seriously thermal stability.

Internet Survey에 관한 연구

이성희,정병택 목원대학교 사회과학연구소 1999 社會科學硏究 Vol.- No.3

일반적으로 사회과학분야의 연구에서는 응답자의 태도 및 의견을 "질문지"라는 매체를 통해 연구가설이 과학적 타당성을 부여한다. 최근 인터넷 및 컴퓨터의 빠른 보급으로 인해 이윤을 목적으로 하는 단순 앙케이트에서 여러 연구분야에서 인터넷을 통한 여론조사를 검토중이며 확산될 전망이다. 따라서 본 연구에서는 인터넷을 통한 여론조사방법을 개괄하고, 이에 필요한 환경 및 집계방법을 제시하는데 있다. 또한, 통계패키지 SAS를 이용하여 분석한 사례를 제시한다.

SOCCER SYSTEM의 變遷使的 考察

鄭相澤 慶北大學校 體育科學硏究所 1992 체육과학연구지 Vol.8 No.-

In 1863, Cambridge University enhanced the soccer play to the systematic sports by formulating 14rules similar to the rules of recent days. Based on those rules soccer games had been made popular all over the world and developped as a game between clubs, countries. When the soccer system was devised to make manifest the performance of the 11 players to the maximum degree, the soccer game accomplished its further development. Such systems have developped as a new system ceaselessly among the soccer powers participating in the World Game. These countries have used another new system every time they took part just like the fashion styles. The purpose of this study is to clarify the change of soccer systems to enlarge functionally the players abilities, and to see the advancement of soccer play in the future.

해양온도차발전 Closed and Regeneration Cycle의 기본 정특성

차상원(Sang1Won Cha),김유택(You1Taek Kim),이영호(Young1Ho Lee) 한국유체기계학회 2011 유체기계 연구개발 발표회 논문집 Vol.2011 No.11

Ocean Thermal Energy conversion(OTEC) technology is one of OTEC technology refer to a mechanical system that utilizes the natural temperature gradient that exists in the tropical ocean between warm surface water and the deep cold water, to generate electricity and produce other economically valuable by-products. The selection of working fluid and working conditions of the OTEC’s cycle has a great effect on the system operation, and it’s energy efficiency and impact on the environment.Working fluids of the OTEC is Ammonia, R22, R407c, R410a. Ammonia have a large heat capacity. But, ammonia is difficult to treat. R22 has been proposed as the working fluid instead of ammonia due to toxicity problems, it would be prohibited according to the Montreal Protocol. Therefore, more research is needed on developing more suitable working fluid substitutes. It is a R407c, R410a. In this paper, the optimization of and Ocean Thermal Energy Conversion(OTEC) system is carried out by the Powell method (according to the Workin g Cycle and Working Fluids).

Piaget의 理論에 根據를 둔 數學學習敎材의 保存性에 關한 硏究

朴成澤 부산교육대학교 과학교육연구소 1988 科學敎育硏究 Vol.13 No.-

The purpose of this paper is to analyze mathematical contens of piaget's theory of intellectual development and to explore the conservation of mathematics-learning subject-matter on the above fact analyzed. The results of this study are following: 1) The development of cognition has a specific order and the acquisition of knowledge is formed with the interaction of experience and reason. 2) Arithmetic subject-matter contents are selected and the sequence of them were organized on the basis of the developmental level of quantitative concept conservation shown by piaget. 3) For elementary children discovery learning by the inductuon through the operative teaching-learning principle is efficient.

誤差의 傳播에 關하여-I

辛翔澤 釜山水産大學校 1970 釜山水産大學 硏究報告 Vol.10 No.2

The formula indicated as (1) derived from the least square method has been applied in the propagation or errors, and this also effects to the propagation of the errors by initial data only. In the process of mass reckoning the propagation of errors as classified in (C) and (D) of the pragraph Ⅱ reduced not to be neglected. Therefore, the author carried out a study with respect to the propagation of the (D) reducted from solving the simultaneous linear equations by the method of elimination, and derived a expression (3). It was found that the calculated errors by the above expression almost coincide with the given definite errors in examples of (2) and (3).

Starter 및 멸치액젓 첨가가 김치양념 및 겉절이 김치의 품질에 미치는 영향

최택권,박소희,유진현,임호수,조재선,황성연 한국식생활문화학회 2003 韓國食生活文化學會誌 Vol.18 No.2

양념에 Leu. mesenteroides, Lac plantarum의 젖산균과 멸치액젓 첨가가 김치 양념의 대장균군 제어, 속성촉진여부 및 관능적 특성에 미치는 영향을 조사하였다. Leu. mesenteroides과 젓갈을 첨가한 경우 초기 숙성이 촉진되나 후기 산패는 완만하였으며 Lac. plantarum의 첨가시에는 초기 숙성에는 큰 차이가 없고 후기 산패가 현저하게 진행되었다. 대장균군은 산도 0.80% 이상에서 사멸되었는데 leu. mesenteroides의 경우가 숙성이 촉진되어 보다 신속히 사멸시켰다. 총균수와 젖산균수는 초기에 starter 첨가구는 10^6CFU/mL 정도인데 반해서 starter를 첨가하지 않은 않은 처리구에서 총균수는 10^6CFU/mL , 젖산균수가 10^4CFU/mL 이었고 숙성 후에는 첨가균이 높은 수준을 유지하였다. 하지만 대체적으로 스타터의 첨가가 숙성 및 대장균에 크게 영향을 주지 못하는 경향으로 동일하게 나왔다. 관능적 특성에서는 Leu. mesenteroides 첨가구가 Lac. plantarum의 경우보다 우수하였다. 한편, 시판 겉절이 김치는 산도가 0.09~0.18%, ph 5.46~5.89, 총균수 2.2×10^6~3.1×10^7CFU/mL, 젖산균수는 2.1×10^4~6.6×10^5CFU/mL, 대장균수는 1.8×10^4~7.1×10^5CFU/mL, 염분 1.89%~2.51%으로 스타터 첨가 겉절이에 비해 ph와 염도를 제외한 품질 특성에서 전반적으로 낮은 값을 나타냈다. This study was performed in order to investigate the effect of Leuconostoc mesenteroides, Lactobacillus plantarum and salt fermented anchovy extracts on Kimchi sauce. The sauce was fermented more rapidly by addition of Leu. mesenteroids or salt fermented anchovy extracts on the early fermentation stage than the control, but it was fermented slowly on the late fermentation stage. When L. plantarum was added to the Kimchi on the early fermentation stage, the acidity of Kimchi didn't show a significant difference from the control, but acidity was remarkably increased on the late stage. Coliform group was disappeared when acidity of sauce was higher than 0.8% during fermentation. It was controlled by Leu. mesenteroides but not by L. plantarum. Total count and lactic acid bacterial count of the sauces with starter were 6.30×10^6~1.0×10^7 CFU/mL and 1.04~2.04×10^6 CFU/mL, respectively, but those of the control sauce were 10^6 CFU/mL and 10^4 CFU/mL, respectively. Those count of the sauce with starter were higher than those of the control sauce on the later stage of fermentation. Organoleptic quality of the sauce with Leu. mesenteroides was superior to that with L. plantarum.