• Journal of Radiation Protection and Research
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• v.36 no.3
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• pp.134-139
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• 2011

In this research, we developed the newly cloud chamber apparatus by using Peltier device to apply nuclear physics experiment in high school or university. We observed the cosmic rays track by using the developed apparatus and a camcorder. And we compared and analyzed the acquired data. From the results, we acquired the following conclusions and suggestions : First, it is very difficult to observe the cosmic rays track in the typical cloud chamber because of the low frequency of it. But in the newly developed cloud chamber we can observe easily the cosmic rays track owing to the high frequency of it. Second, when we do the experiment with the newly developed apparatus, we found that the cosmic rays track happens well under the condition that the temperature of the upper place of cooling plate must be below 5$^{\circ}C$ with more than isopropanol $1.04{\times}10^{-5}$ $ml{\cdot}mm^{-3}$. Third, the newly developed apparatus will be improved to have better precision by controling the temperature of cooling plate in the cloud chamber by current intensity. Therefore we think that it is very useful to use the newly developed apparatus in the nuclear physics experiment in highschool or university.

• Tunnel and Underground Space
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• v.30 no.2
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• pp.164-179
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• 2020

Applying the limit state design method to geotechnical structures, accuracy and reliability of its design are mainly affected by parameters for geotechnical site characteristics, such as unit weight, Poisson's ratio, deformation modulus, cohesion and frictional angle. When the structures are located in weathered ground, especially, cohesion and frictional angle of ground are closely related with decision of parameters for structures' load and ground's resistance. Therefore, the accurate determination of these parameters, which are commonly obtained from field measurement, such as borehole shear test, are essential for optimum design of geotechnical structures. The 38 case studies, in this study, have been analyzed for understanding the importance of these parameters in designing the ground structures. From these results, importance of field measurement was also ascertained. With these evaluations, an apparatus for determining the strength characteristics, which are fundamental in limit state design (LSD) method, have been newly developed. This apparatus has an improved function as following the ASTM suggestion. Through the field application of this apparatus, the strong point of minimizing the possibility of error occurrence during the measurement has been verified and authors summarized that the essential parameters for LSD can be qualitatively obtained by this apparatus for determination of strength characteristics of weathered ground.

• Journal of Fisheries and Marine Sciences Education
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• v.19 no.1
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• pp.150-160
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• 2007

The school system of fisheries high school was proper to specialist objective school system in order to training for expert human resource development.Training a field of human resources development from fisheries high school is fallow; fisheries production, seamen's training, ship engine and refrigerator, marine electronic telecommunication and information, fisheries foods production and fisheries foods production and distribution, fishery fisheries self-management, marine distribution, management and conservation of marine environment, safety and marine prevention of disasters, apparatus of marine development, under water area development.A new department opening and each department was revised toward to department name and department character. The unit-lesson hour of curriculum according to specialist objective school system of fisheries and marine highschool was revised. professional subject 98 unit-lesson hour(52%), normality subject 90 unit-lesson hour(48%), and educational activity of professional subject 10unit-lesson hour, total training activity 10 unit-lesson hour. And the special objective school system need to revise curriculum of 208 total unit-lesson hour.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.122-124
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• 2005

Underground distribution system is a trend due to the successive development of metropolitan area and satellite cities and the environment of the commercial and residential areas. The high quality of electricity, which is related with the minimal outage duration time due to the maintenance work for the underground distribution line, is mandatory. Hence, the construction method and tools for the outage-free maintenance construction have been required for underground distribution system. So far, all the efforts for outage-free maintenance for the underground distribution have been limited only to the survey for foreign countries situation and the theoretical provision; thus, It is required to develop the various construction method and the application tools. Differently from the aerial line, the construction of the underground cable is complicated and the insulation distance between conductor and shield should be maintained in loadmaking/breaking operation, though the apparatus connected with cable is a deadfront type. Also since the apparatus is installed above ground, by-pass of faulted area at busy area needs a variety of high technologies. Therefore, in this these, the authors introduce the development status of the loadbreak connectors, connection facilities, outage-free maintenance system for secondary side, a secondary auxiliary bushing and additional tools so that there can be more progress on this field.

• Korean Journal of Medicinal Crop Science
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• v.12 no.3
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• pp.209-213
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• 2004

Ligusticum chuanxiong is receiving much attentions as one of the important medicinal crops with the increasement of the crude drug demands. This study was conducted to obtain the basic informations of breeding of Ligusticum chuanxiong. Embryological characteristics were examined to elucidate the process of male and female gametophytic development and fertilization. Meiosis and nucleus division of megaspore and microspore were proceeded normally. With regard to the formation of female gametophyte, only a half of female gametophyte developed to normal egg apparatus. While another 50% showed abnormal egg apparatus with poly-nuclei or non-nuclei ovule. The pollens developed from the micros pore were formed more than 90 % of normal pollen. It was difficult to observe fertilization because ovule tissue was very compact and cell was extremely tiny, but could be easely observed proembryo and embryo formation. Only 30 percent developed into proembryo and subsequently into embryo, and the others were degenerated.

• Journal of the Korean earth science society
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• v.31 no.1
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• pp.88-94
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• 2010

A simple laboratory device and methodology are developed for deep understanding of the western boundary current (WBC). The apparatus consists of a rotating (count-clockwise) rectangular tank with a sloping bottom in order to simulate the beta effect, the variation of the Coriolis parameter with latitude. We also used a clockwise rotating disk at the surface water to mimic the wind stress forcing in mid-latitude oceans. Four experiments were carried out using some combination of a bottom type and a rotation of the tank. Experiment with the beta effect clearly demonstrated the WBClike flow as well as the Sverdrup interior. However, the water in a tank gave rise to an inertial motion under the influence of a constant Coriolis force alone. We also discussed a stiffening of the rotating fluid on the basis of the Taylor-Proudman effect. We believe that the apparatus and methods developed in this study help to understand the WBC due to the beta effect.

• Journal of Advanced Marine Engineering and Technology
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• v.15 no.4
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• pp.29-45
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• 1991

Lip type stern tube sealing systems have used in almost all the middle or large ships which are being constructed in these days. It seems that the pressure fluctuation of the seal ring interspace, the cross-section profile and the materials quality of the seal rings have great effects on the sealing fuction of this sealing system. In this paper, the mechanical movement of lip seal ring which plays the most important role in stern tube sealing system and the possibility of leakage caused by pressure fluctuation are studied by theory and experiment. Using the finite element method for the axi-symetric object which receives the torsional load, the displacement and stress analysis of the seal rings, and also the possibility of crack occurance is checked by theoretical analysis. If the force which seal ring lip periphery receives is too small, there will be the possibility of leakage caused by the pressure fluctuation of the seal ring interspace, and if this force is too large, the frictional force between the seal ring and the liner will become problematical. The possibility of leakage caused by hardening of seal ring materials and creep phenomena of tested seal rings are also examined. The trial seal rings were designed and manufactured using the program of displacement and stress analysis developed in this study and the experimental apparatus to test the trial seal rings was also designed and manufactured. This trial seal rings were fitted in the experimental apparatus which was made in the same form as an actual stern tube. The one side of this apparatus was filled with sea water and the other side of it was filled with the lubricating oil. The leakage of oil and sea water was checked and the temperature was measured, rotating the propeller shaft at the constant velocity by D.C. motor. It was proved that the trial seal rings made in Viton rubber functioned excellenty but the trial seal rings made in N.B.R. rubber had problem in its durability.

• KSCI Review
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• v.14 no.2
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• pp.165-174
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• 2006

This paper is a matter of remote control apparatus and display remote control system comprising the same. The remote controller is a wireless remote pointing device that is included a function of mouse and a function of remote controller for VOD etc. It is assembled a sending signal part to communicate with display device, a image sensor part to capture a seen of front view and a main body. Also, it includes a control part that analyzes the captured image, calculates a relative moving factor that main body is moved by user, and then controls the mouse cursor on the display device. The remote control apparatus is able to capture a seen of front view, to analyze the captured image, and to move a mouse cursor point on the display device as much as it calculated relative moving factor. Therefor it brings down the cost of production by a product design that is increased user satisfaction. And it, using the patent and the new product design, will make an epoch in development of the remote control system for Ubiquitous broadcasting industry.

• Journal of the Korean Geosynthetics Society
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• v.10 no.4
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• pp.93-103
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• 2011

In order to design suitable geo-structures in cold region, it is generally required to consider the mechanical properties of permafrost soils. 'Frost heave' as one of the primary phenomenon is considered to be an important factor together with 'adfreeze bond-strength' and 'creep deformation' for structural design process in permafrost area. Therefore, the fundamental study for frost heave has to be preceded for design of geo-structures in cold region. While various experimental apparatuses have been developed, there still exist a certain level of limitation to evaluate the frost-heave characteristics as design parameters. In this paper, a new type of experimental apparatus is proposed to evaluate the engineering characteristics of frost heave in permafrost soils and a set of verification test results is presented. Based on the verification tests, the proposed apparatus is a suitable to obtain frost characteristics of soils.

• Journal of the Korean Vacuum Society
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• v.12 no.3
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• pp.157-161
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• 2003

Nowadays there are increasing demands for more accurate measurement of atmospheric pressure according to the development of environmental industries. One of the most important pressure gauges for satisfying these demands is a quartz resonance barometer. In order to calibrate such an accurate barometer, laser/ultrasonic mercury manometers have been used. However, complexity and cost of mercury manometers made it out of use gradually. As a substitute, a gas-operated pressure balance is used for calibration of precise barometers. In such a case, commercially available pressure balances cannot be entirely suitable because consequent exposure of the piston, cylinder and masses to the atmosphere causes the problem of contamination. In this paper a device for changing the masses in situ without breaking the vacuum is described. This device made it possible to add or remove weights in the absolute mode, thereby greatly reducing the time between observations. At the same time, we investigated the characteristics of a commercial precise barometer using this new apparatus.