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PASS (polyamic acid alkylamine salts) LB막의 유전 특성
강도열,김태완,박준수 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.4 No.-
Dielectric properties of PAAS LB films were studies in a frequency range of 10 Hz to 13 MHz. Y-type films were made under a surface pressure of 30mN/m using Kuhn type apparatus. It was found that there is a dielectric dispersion of electric polarization near 105 Hz. The effect of electric polarization was also confirmed by charging and discharging current under an application of dc voltage.
저밀도 폴리에틸렌에서 불순물 혼합량에 따른 트리진전과 방전펄스와의 관계 연구
姜道烈,朴懷俊,金正洙 弘益大學校 1982 弘大論叢 Vol.14 No.2
It is well known that, when enough high voltage is applied to a high-voltage cable with an insulator, treeing phenomenon can occur due to void or impurities such as dust, metal powder, etc. inside the insulator. Also,it is known that this treeing phenomenon drastically shortens the life of the insulator. In this paper, we investigate the effects of the mixture ratio of impurities to the Low-Density Polyethylene used as an insulator on the treeing phenomenon based on the electrical characteristics. As impurity samples, Al₂O₃ and SiO₂with the particle diameter of 44μm have been used for different weight mixture ratios of 1%, 5%, and 10%, respectively. Since the treeing phenomenon occurring in the sample, based material of Low-Density Polye thylene mixed with 1% impurity can easily be observed with an optical microscope, we have first investigated the relationship between the result measured from electrical characteristics and the one obtained from observation with an optical microscope. Specifically, it has been found that the total number of pulses measured from the eletrical waveform of the treeing phenomenon is closely related with the growth length of the tree observed with an optical microscope. Based on these results, the growth length of the tree for the other sample materials with 5% and 10% impurities could be estimated from the total number of the electrical tree pulses for these sample materials, respectively. As a result, it has been found that the effect of the treeing phenomenon decreases as the mixture ratio increases. Also, it is shown that the total number of the electrical tree pulses makes it possible to predict the effect of the treeing phenomenon without observing with an optical microscope.
李康寧,高永杜,金正敎,河浩成,姜奉淳,朴道秉,姜淮 慶尙大學校 1978 論文集 Vol.17 No.2
This study attempts to analysis the present situation of farm management and the related industriesin order to present the suitable industries for promoting the farmers' income in mountain area. This study is based on the survey data obtained from 30 sample mountain vellages in 10 Guns located in central, wetern and northen Kyeougnam Province, where lots of mountain vellages are scattered here and there. Major findings obtained from the analysis are summarized as follows: 1) Area of cultivated land in mountian villages was generally smaller than that in plain vellages. BUt major finding of thes tudy indicated that the standard of living in the study area depended upon not only the size of cultivated land but also the skills of management to understand exavtly the regional and togographical situaltion, to utilize the developmental resources effectively, and to diversify income sources. This means that upbringing of competent Saemaul leaders is very important for promoting the income of mountain villages. 2) Various crops were being planted in a samll scale inmountain area. And those crops except rice adn barley were planted for self-sufficiency. Therefore, it is desired to select and cultivate intensively the kinds of crops which are regionally adn topographically suitable for maximizing farm inceomes of subsistant farmers. 3) The survey found out that in mountain area the farming of extensive fruits like chestnuts, persimmons, etc. is more favorable than that of intensive fruits like apples, pears, etc. 4) Because of topographical inappropriateness and lack of fertile cultivates land in mountain area, mowt vegetables, except onions in a few regions, were growing in a small scales for self-sufficiency. And the future of the vegetable cultivationin mountain area is also gloomy. 5) Since various grasses are abundantly growing in the wild in mountain area, the mountain villages are suitable for raising the herbivorous animals. Therefore it is recommeded to encourage raising the herbivorous animals, especially cattle, as one of the major income sources in mountain area. 6) It is true that sericulture has greartly contributed to the economic growth in mountain area with aboundant land suitable for mulberry trees. Recenly sericulture has, however, been shrinking due to the barriers of silk exportation. Without the barriers of silk exportation, sericulture will still play an important role on providing one of the major sources tom mountain villages. 7) The miscellaneous trees in most forest around the mountain villages were growing planlessly. Those parts of the forest are needed to be renewed by planting the useful, endurable, and regionally and topographically suitable kinds of trees.
폴리에틸렌 테레프탈레이트(PET)의 內部摩擦損 및 誘電損의 溫度特性에 關한 相關性 硏究
李準雄,康道烈,金在煥,金鳳洽 光云大學校 1982 論文集 Vol.11 No.-
This paper investigated comparatively the temperature dependence of dielectric α relaxation process and dynamic mechanical α relaxation process. Dynamic mechanical and dielectric loss data on a given polythylene terephthalate (PET) are generally viewed as being directly comparable. This is based on the notion that, if each exhibits a loss peak at about the same temperature and frequency, they must be manifestations of the same process. This supposes that the process couples in the exact same manner with both mechanical and electrical stress fields. That this need be so may be seen from the fact that not only non polar process give rise to dynamic mechanical losses, but also dipolar losses. The results obtained are as follows. 1) Dielectric α peak and dynamic mechanical α peck in PET are observed at almost same temperature correspondently. 2) The elongated sample exhibits the higher α peck at the almost same maximum temperature. 3) The magnitude, location and breadth of the α relaxation in PET are strong function of the degree of crystallinity and also the manner in which a particular degree of crystallinity is attained. And the degree of crystallinity is changed with external conditions, that is, density, annealing. quenching, drawing, orientations and irradiation etc. 4) In the results of observation the absorption peak at 1,788 ?? on infrared spectra, the more bigger concentration of carbonyl dipole group was observed on the elongated sample.
李永俊,李根鎬,金熙東,李元宰,姜道烈 弘益大學校 1988 弘大論叢 Vol.20 No.2
In this paper, Thermally stimulated current(TSC) spectrum was mearsured as a function of formation temperature, formation time, formation voltage and heating rate in a biaxially oriented polypropylene film of thickness 40[μm], which is better than polyethylene in the enduring characteristic against heat and dielectric characteristic, the variation of the TSC was observed by ozone oxidation. This measurment has been carried out in the temperature range from-40[℃] to 140[℃]. As results of the measurment, A,B,C,D peaks was made at 0[℃], 40[℃], 80[℃], 120[℃], respectively. B peak was made at the near second glass transition temperature is estimated the dipole polarization by microbrown motion, C peak is estimated to the polarization of ionic space charge. And, In according to the increase of oxidation time by ozone, B peak increased slowly and C peak increased rapidly after it increased slowly during first oxidation time of 15[Hr]. By initial rising method, activation energies of B,C peaks were calculated to about 0.57, 0.84eV, respectively. The hopping distance and mobility of C peak for pure specimen and ozone oxidated specimen 54A, 71A and 1.099×10??cm²/υ·s, 8. 55×10??cm²/υ·s, respectively.