• Journal of Radiation Protection and Research
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• v.28 no.1
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• pp.19-24
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• 2003

The self-attenuation factor for an $^{198}Au$ sample and the 0.412 MeV gamma-ray penetration ratio in the circular Al-cover of the radiation detector have been determined using an analytical solution and MCNP code. The results show that the self-attenuation factors obtained from the analytical solution coincide with those of MCNP code for all but the Au sample with the relatively larger radius. Then the maximum difference between the two methods appears to be 9 % in the Au sample of 1.5 mm radius. It also is revealed that the analytical solutions of the 0.412 MeV gamma-ray penetration ratio in the Al-cover of 7.62 cm radius are consistent with those of the MCNP code within the standard deviation.

• The Mathematical Education
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• v.41 no.1
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• pp.19-34
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• 2002

The 7th national mathematics curriculum lays emphasis on an interrelation of several subjects and a connection between mathematics and real life. In this reason, this study focuses on the enhancement of sound understanding nuclear energy which is one of important factor(concepts or contents) dealt with in the other subjects such as science, environment, social studies, etc.. Recently, even though it is insistent that nuclear energy be so important and request in the future society, there are still strong pro and cons regarding the use of it. In this study, teaching-and-learning materials were developed dealing with using nuclear energy, and consequently they might be used in math class for the purpose of enhancement of mathematical learning ability and of recognition on nuclear energy. In this study, Material 1 included a matter of the necessity for nuclear power plants using the ratio concept, and Material 2 did on a matter of the efficiency of nuclear energy and the unclear of nuclear power plants using ratio-graph, in the elementary and upper school mathematics. Material 3 focused on a matter of the principles of nuclear power plants using the properties of exponential law in high school mathematics. Ultimately, it is hoped in the study that more diverse instructional materials dealing with diverse situations inside and outside mathematics would be developed.

• Earthquakes and Structures
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• v.3 no.5
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• pp.749-766
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• 2012

Structural control through integration of passive damping devices within the building structure has been increasingly implemented internationally in the last years and has proven to be a most promising strategy for earthquake safety. In the present paper an alternative configuration of an innovative energy dissipation mechanism that consists of slender tension only bracing members with closed loop and a hysteretic damper is investigated in its dynamic behavior. The implementation of the adaptable dual control system, ADCS, in frame structures enables a dual function of the component members, leading to two practically uncoupled systems, i.e., the primary frame, responsible for the normal vertical and horizontal forces and the closed bracing-damper mechanism, for the earthquake forces and the necessary energy dissipation. Three representative international earthquake motions of differing frequency contents, duration and peak ground acceleration have been considered for the numerical verification of the effectiveness and properties of the SDOF systems with the proposed ADCS-configuration. The control mechanism may result in significant energy dissipation, when the geometrical and mechanical properties, i.e., stiffness and yield force of the integrated damper, are predefined. An optimum damper ratio, DR, defined as the ratio of the stiffness to the yield force of the hysteretic damper, is proposed to be used along with the stiffness factor of the damper's- to the primary frame's stiffness, in order for the control mechanism to achieve high energy dissipation and at the same time to prevent any increase of the system's maximum base shear and relative displacements. The results are summarized in a preliminary design methodology for ADCS.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.1
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• pp.1-7
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• 2015

In this study, characteristics of reforming process of automotive liquefied petroleum gas (LPG) fuel using plasma reactor are investigated. Because plasma reformer technology has advantages of a fast start-up and wide fuel/oxidizer ratio of operation, and reactor size is smaller and more simple compared to typical combustor and catalytic reactor, plasma reforming is suitable to the on-board vehicle reformer. To evaluate the characteristics of the reforming process, parametric effect of $O_2/C$ ratios, reactant flow rate and metal form on the process were investigated. In the test of varying $O_2/C$ ratio from partial oxidation to stoichiometry combustion, conversion of LPG was increased but selectivity of $H_2$ decreased. The optimum condition of $O_2/C$ ratio for the highest $H_2$ yield was determined to be around 1.0 for 20~50 lpm, and 1.35 for 100 lpm. Specific energy density (SED) was major factor in reforming process and higher SED leads to higher $H_2$ yield. And metal form in the reformer increased $H_2$ yield of about 34 % as compared to the case of no metal form. The result can be a guide to map optimal condition of reforming process.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.9
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• pp.1681-1690
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• 1992

The effects of the stress ratio and the fiber orientation(0.deg./90.deg. and .+-.45.deg.) to the load direction on the fracture behavior of the glass/epoxy plain woven composites were studied. The tests were carried out using compact tension specimens under both static and fatigue loading. The values of $k_{a}$ obtained from the energy release rate are independent of notch depth(a/w=0.2~0.6) for the 0.deg./90.deg. specimens, but decreases with an increase in a/w for the .+-.45.deg. specimens. And $k_{q}$ has higher values than $k_{ASTM}$ has been evaluated by the ASTM E399 test procedure. It is shown in the relation between fatigue crack growth rate da/dN and stress intensity factor range .DELTA.K using modified shape correction factor that da/dN decreases with a decrease in stress ratio and is lower for .+-..deg. specimens than for 0.deg./90.deg. These phenomena can be explained by the crack deflection to the load direction.n.n.

• Journal of Environmental Science International
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• v.25 no.2
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• pp.281-288
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• 2016

After analyzing of heating value of four kinds of RDF, the RDF-D has the highest heating value, was chosen to be mixed with carbonized sludge by different ratio. The 85%:15% ratio, which has the highest efficiency, was analyzed with thermogravimetric and pyrolysis kinetics. Applying of Kissinger method, activation energy was obtained from slope which is calculated from relation of ln(${\beta}/T^2{_m}$) and $1/T_m$. The kinetic parameters obtained from Kissinger method were 46.06 kJ/mol of RDF, 55.99 kJ/mol of carbonized sludge and 40.68 kJ/mol of mixture of RDF and carbonized sludge. The mixture of RDF and carbonized sludge has the lowest activation energy and frequency factor, during thermal decomposition reaction it has the slowest reaction rate and needs the lowest energy. Although activation energy with pyrolysis of RDF was irregularly scattered, it showed that activation energy was stabilized by co-pyrolysis of RDF and additives(Carbonized Sludge).

• Journal of Acupuncture Research
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• v.25 no.2
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• pp.139-149
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• 2008

Objectives : The 7-zone-diagnostic system is a diagnostic device to predetermine bodily locations by measuring the energy of body. This study was to investigate the relation between the different patterns of Zone 2, 6 of Factor AA in VEGA DFM 722(VEGA, Germany), 7-zone-diagnostic system and clinical parameters. The purpose of this study was relation Korean traditional medicine and western medicine with the data from 7-zone-diagnostic system and the clinical parameters. Methods : This study was carried out with the data from some clinical parameters. We made two groups according to the Factor AA patterns of VEGA DFM 722. The Factor AA pattern of Group A is that the red bar graph of zone 2 was higher than the normal range and the red bar graph of zone 6 was lower than the normal range. The Factor AA pattern of Group B was that the red bar graph of zone 2 was lower than the normal range and the red bar graph of zone 6 was higher than the normal range. After the data from clinical parameters to correspond with conditions of each group were selected, the data from clinical parameters between each gropus analyzed statistically. Results and Conclusions : The values of Direct Bilirubin, GOT, BUN and BUN/Creatinine ratio of Group A were higher than them of Group B. The values of Sodium and Tyroxine of Group A were lower than them of Group B. These results mean that Group A has low energy but has increading tendency. To conclude, it is thought that the red bar graph of zone 2 is higher, the group is the more increasing and the red bar graph of zone 6 is lower, the group has the lower energy.

• Journal of Nutrition and Health
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• v.34 no.1
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• pp.89-97
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• 2001

The relationship among food behavior, psychological factor(life strees) and perceive tiredness was investigated in 514 adolescents. Tiredness was measured in four cases: in lessons, before school, in the early evening and at weekends. Adolescents felt most tired in lessons and before school, and leat at weekends. Irregularity of meal times and skipping breakfast were positively correlated with tiredness in lessons and befor school. Consumption of some foods was related to perceived tiredness. High sugar or fat containing ice-cream, hamburger of fizzy drinks in boys, and crisps and cookies in girls were positively associated with tiredness. Whereas beans and mushrooms were negatively associated with tiredness in girls. Life stress(by scholastic problem and personal problem) of adolescents was positively related to tiredness. The contribution of stress to tiredness was much greater than of food behavior according to multiple linear regression .There was no relationship between nutrients intake and tiredness in lessons and before school which were more strongly influenced by stress, whereas the relationship was found at weekend without influences of stress. The more tired, the lower NARs(nutrient adequacy ratio) of energy, phosphorus, vitamin A, vitamin B$_2$, and niacin were. In conclusion, some eating behavior and psychological factor can cause tiredness in adolescents, but tiredness in school and before school had more of a psychological cause than at weekend. (Korean J Nutrition 34(1):89-97, 2001)

• Journal of Power System Engineering
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• v.14 no.3
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• pp.33-38
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• 2010

Technology of vehicle industry has been developing and it is required a better vehicle performance than before. Therefore, the consumers are asking not only an economic efficiency, functionality, polished design, ride comfort and silence but also a driving stability. The ride comfort, silence and driving stability are influenced by the size of vehicle and various facilities. But the principal factor is a room noise and vibration sensed by a driver and passenger. Thus, the NVH of vehicle has been raised and used as a principal factor for evaluation of vehicle performance. The primary objective of this study is an optimized design of powertrain mounting system. To optimized design was applied MSC.Nastran optimization modules. Results of dynamic analysis for powertrain mounting system was investigated. By theses results, design variables was applied 12 dynamic spring constant. And the weighting factor according to translational displacement and rotational displacement applied 3 cases. The objective function was applied to minimize displacement of powertrain. And the design variable constraint was imposed dynamic spring constant ratio. The constraint of design variable for objective function was imposed bounce displacement for powertrain.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.234-238
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• 2008

The energy conservation theory is introduced for investigating processes of runoff and soil erosion on the hillslope system changed vegetation condition by wildfire The rainfall energy, input energy consisted of kinetic and potential energy, is influenced by vegetation coverage and height. Output energy at the outlet of hillslope is decided as the kinetic energy of runoff and erosion soil, and mechanical work according to moving water and soil is influenced dominantly by the work rather than the kinetic energy. Relationship between output and input energy is possible to calculate the energy loss in the runoff and erosion process. The absolute value of the energy loss is controlled by the input energy size of rainfall because energy losses of runoff increase as many rainfall pass through the hillslope system. The energy coefficient which is dimensionless is defined as the ratio of input energy of rainfall to output energy of runoff water and erosion soil such as runoff coefficient. The energy coefficient and runoff coefficient showed the highest correlation coefficient with the vegetation coverage. Maximum energy coefficient is about 0.5 in the hillslope system. The energy theory for output energy of runoff and soil erosion is presented by the energy coefficient theory associated with vegetation factor. Also runoff and erosion soil resulting output energy have the relation of power function and the rates of these increase with rainfall.