• Journal of Power System Engineering
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• v.17 no.3
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• pp.111-122
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• 2013

After the port opening in 1876, the western people made joseon image as the land of morning calm. there was a conception that joseon was a uncultivated country in the meaning of the land of morning calm. famous modernists such as gil-jun yu, kwang-su lee also had same conception. but such conception began to change in 1930's. the number of motor vehicle began to increase rapidly in 1930's. and also many of motor vehicle were equipped with air horn or electronic horn instead of bulb horn. bulb horn made thick and low rubber sound. but air horn or electronic horn made sharp and high metallic sound. city people of colonial joseon began to recognize air horn or electronic horn as city noise. so they tried to control the use of air horn or electronic horn. finally, in late 1930's, the use of air horn and electronic horn were prohibited.

• Journal of Korean Elementary Science Education
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• v.23 no.2
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• pp.116-122
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• 2004

The purpose of this study is to investigate effects of computer animations using particulate model in elementary science classes related to air pressure. To do those, four classes of 5th grade in an elementary school located in a city were selected. As an experiment group, two classes were applied the teaching materials of computer animations developed for this study based on particulate model. The other classes as a control group were not applied these materials in science classes. The total scores of experiment group in which computer animation using particulate model was applied in science classes are higher than those of the control group in the conception test. Only in one conception related to high and low atmospheric air pressure, the scores of the two groups are not significantly different at 0.05 significance level.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.185-188
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• 2003

Data on the use of breeding records of dairy cattle farm of Fenghuang-shan in Chengdu areas during a period of six years is systematically analyzed. The results show that Holstein heifers have their 1st estrus at an average age of $513.6{\pm}46.7$ d which is not related to the calving season. Estrus mostly occurs in the months with mild ambient temperature (March, April, May, November and December). There is a very poor rate of estrus detection; only 30.0% successive estrus is observed within 24 d, 29.3% within 25-48 d, 40.6% over 48 d. The average number of insemination per conception is 1.50 for heifers and 1.74 for cows, but conception rate (CR) is lower in the relatively warm months (July, August and September) ranged from 48.1% to 51.9% compared with 58.1% to 68.5% in other months. High temperature is the most important factor affecting fertilization in warm months, but neither did CR decline immediately with the increased air temperature in June, nor did it increase immediately with the declined air temperature in September. Post partum anestrous period is $119.5{\pm}60.5$ d. The average interval from calving to conception is $159.4{\pm}85.6$ d with only 19.8% of the cows conceived within 85 d of calving. Cows with high milk yield have longer acyclic periods and lower conception rates. Improvement of efficient managements must be a precedent condition in Chengdu areas.

• Journal of The Korean Association For Science Education
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• v.13 no.1
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• pp.92-99
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• 1993

The purpose of this study was to investigate and analyze the conception of elementary school students on evaporation and condensation, and then to verify the types of the conception. Forty-eight children from six elementary schools were sampled by stratified random sampling in Seoul and other provinces. They responded to the questionaire and the interview. This study was carried out according to the process of the basic study, the preliminary study, and the main study. The materials collected were classified and analyzed according to the types of children's ideas. The findings of this study were as follows. 1. The vocabulary used to describe the evaporation phenomena varied according to the situations, and the scientific term "evaporation" was more frequently used by the older groups. 2. Most children answered that the last location of water were air/sky/cloud. Air/cloud which represents the scientific conception of the location of water were mentioned by children of all ages. The higher the grade of the children were, the more scientific conception the children mentioned, however. 3. Most children referred to the heat as the factor of evaporation. Wind, on the other hand was mentioned by less than 10% of lower graders, and by about 30% of higher graders. 4. The result of asking children whether they thought it was possible to get the evaporated water back showed that about 70% of lower graders denied the possibility of the water being reversible. About 60% of higher graders. however, recognized that the water will be returned as rain or condensation. This increase may be associated with formal teaching of water cycle. 5. In the ideas of evaporation and condensation, some of the children have supernatural ideas and animism, which are most younger chilren's characteristics.

• Journal of the Korean Society of Earth Science Education
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• v.4 no.1
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• pp.57-65
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• 2011

The purposes of this study investigated the effects of placement of analogy on the conceptual changes of air of elementary students, while learning the air conceptions. The subjects consisted of 108 students who are in the sixth grade classes in an elementary school in Busan city. For this study, comparative group(37 members), experimental group I(37 members), and experimental group II(34 memgers) were selected. A pre-test and a post-test on the air conception were done both for the comparative group and the experimental groups. The results are as follows. First, the averages of experiment group I and II are statistically higher than comparative group's. By the way, it just has a small gap between the comparative group and the experimental II. In other words, activity of analogy does not keep always constant to change of air conceptions of elementary students. Therefore, it has a different reason that only before or after during the analogy. Second, it shows that experimental group I has effected on a more change of air conceptions as compared with experimental group II. Then, the first group's result shows better than the other group's result. From this result, six grade students showed a change of air conceptions very well by analogy. It means if the analogy is given to students at the beginning state of chapter, they can understand scientific concepts easily.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.1
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• pp.82-90
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• 2017

The aim of this work is to develop a new computational program to determine the effect of using the gas of propulsion of combustion chamber at high temperature on the shape of the two-dimensional Minimum Length Nozzle giving a uniform and parallel flow at the exit section using the method of characteristics. The selected gases are $H_2$, $O_2$, $N_2$, CO, $CO_2$, $H_2O$, $NH_3$, $CH_4$ and air. All design parameters depend on the stagnation temperature, the exit Mach number and the used gas. The specific heat at constant pressure varies with the temperature and the selected gas. The gas is still considered as perfect. It is calorically imperfect and thermally perfect below the threshold of dissociation of molecules. A error calculation between the parameters of different gases with air is done in this case for purposes of comparison. Endless forms of nozzles may be found based on the choise of $T_0$, $M_E$ and the selected gas. For nozzles delivering same exit Mach number with the same stagnation temperature, we can choose the right gas for aerospace manufacturing rockets, missiles and supersonic aircraft and for supersonic blowers as needed in settings conception.

• Journal of Korean Medical Ki-Gong Academy
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• v.11 no.1
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• pp.262-283
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• 2009

1. Anus is one of the nine holes, a soul store and on the lungs and the lungs, so the soulgate is said to meet. In addition, weight 450g, length 14.31inch, horizontal, and the 2.74inch, hit the road, the lungs and the reaction of the colon was found to represent the five viscera were dirty. 2. Spirit directly to the anus of the five viscera and the traffic outside and pass the information where I can get, and a close relation to the breathing, and each groups' je-hang-suk-sin-gong, je-hang-gong, anal breathing, jwa-sik training, jung-gi-dan-beop, martial arts method, Kegel exercises, breathing training, such as the anus is the name. 3.Anal way of breathing while breathing naturally slow down when you inhale air, tighten the anus and rectum to release when you breathe out, give way (or vice versa), the number of 5-20, he'll make you build up gradually. 4.Associated with respiratory training in Oriental medicine perspective, it is a Mac gi-gyeong eight vessel. In addition, out of gi-gyeong eight vessel in breathing training and more closely related to the Conception Vessel, Governor Vessel. 5.Governor Vessel, Conception Vessel and connect the energy up, down, left and right to communicate is the so-ju-cheon. To complete the Governor Vessel instantly without the energy leak from the Mir-yeo(尾閭) to reach the anus should be breathing. 6.Start the Conception Vessel Through fare Vessel hoeǔm, hoeǔm important acupuncture point can be activated by itself does not have the muscle to the hoeǔm around the anus energy and blood breathing helps circulation.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.106.4-106
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• 2001

The current research field to find near-optimum solutions explores in a small population, which is coined as Micro-Genetic Algorithms (${\mu}$GAs), with some genetic operators. Just as in the Simple-Genetic Algorithms (SGAs), the ${\mu}$GAs work with encoding population and are implemented serially. The major difference between SGAs and ${\mu}$GAs is how to make reproductive plan for more better searching strategy due to the population choice. This paper is conducted to implement ${\mu}$GAs in order to achieve fast searching for more better evolution and associated cost evaluation in global solution space. To achieve this implementation, the Air-Borne Selection (ABS) for a new reproductive plan is developed as new strategic conception for ${\mu}$GAs. In this paper, it is shown that the ${\mu}$GAs implementation reaches a near-optimal region much earlier than the SGAs implementation. The superior ...

• International Journal of Aeronautical and Space Sciences
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• v.9 no.1
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• pp.1-30
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• 2008

When the stagnation temperature of a perfect gas increases, the specific heats and their ratio do not remain constant any more and start to vary with this temperature. The gas remains perfect; its state equation remains always valid, except, it is named in more by calorically imperfect gas. The aim of this work is to trace the profiles of the supersonic axisymmetric Minimum Length Nozzle to have a uniform and parallel flow at the exit section, when the stagnation temperature is taken into account, lower than the dissociation threshold of the molecules, and to have for each exit Mach number and stagnation temperature shape of nozzle. The method of characteristics is used with the algorithm of the second order finite differences method. The form of the nozzle has a point of deflection and an initial angle of expansion. The comparison is made with the calorically perfect gas. The application is for air.

• The Journal of Aerospace Industry
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• s.49
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• pp.3-40
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• 1999

In this paper, the types of airport operation are categorized four groups in context of ownership and operational management; full government ownership and operation; government ownership with privatization of selected service; government ownership and private management; private ownership and operation. The term,"Privatization" has a different definition when it is used in different contexts and cultures. In this paper, the definition of"Privatization" in the context of airport, is that the movement of an entity from the government sector to the private sector. To keep pace with the remarkable growth in the air traffic volume of passengers and cargo, more and more mega-international airports have been built or are under construction. As the air transport demand is expected to increase at an even greater rate in the 21st century, the need for new conception airport is merging to solve the current problems such as airport congestions and flight delays which will be essential factors to decide whether the competitive airports or not. Presently, we researched the type of the operational management to strengthen the competitiveness for Korea's airports. Specifically, It is focused on the government ownership with privatization of selected services. It seems to be evaluated as government ownership and private management when it is actively utilized within Korea Airport Authority's law or Inchon International Airport's public corporation law. To make more competitive airport in 21st Century, however, it is desirable to seek for the method to gradually evaluate to private ownership and operation.