• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.97-103
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• 2002

Vibration isolation technology using an air spring and laminated rubber bearing is widely used because it has excellent vibration isolation characteristics. In the part of that, we usually make use of the self-damped air suing. It is occupied two chambers, restrictor, diaphragm and load plate. Two chambers contain compressed air and the volume of chambers and the area of load plate give a definition of stiffness and load. The restrictor and the volume ratio of two chambers give a definition of damping ratio. The conventional model of restrictor is made of one orifice and it causes turbulent flow in the orifice at the region of large deflection. The stillness of air suing is larger and the damping is lower in the region of large deflection. In the multi-orifice case, the stiffness is similar to air spring with one orifice but damping ratio is larger than conventional air spring. And damping ratio is smaller than conventional air suing in small deflection region. Deflection is small in the region of high frequency so small damping is better than large damping. As a result, we can reduce the storage stiffness of air suing in the wide region of deflection and increase the damping ratio in the region of large deflection. After this, we will try to and the relation of Reynolds Number and Flow Resistance then we are going to make another restrictor for air spring to improve damping ratio and stiffness.

• Korean Journal of Human Ecology
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• v.5 no.2
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• pp.1-16
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• 1996

This study has examined multiple influences of several variables on parenting behavior by looking into illustrative studies. This study provides support to the view that various factors influence parenting and that parenting behavior is multiply determined. Characteristics of parents, children and the context in which parent-child relations occur cause different childrearing patterns among parents. This study can be summarized as follows: 1) Parental behavior is influenced to a large degree by what the parent brings to the situation. In other words, characteristics of the parent including personality characteristics, interpersonal skills, problem-solving skills, level of maturity, values and childrearing beliefs contribute to individual differences in parenting. 2) The parent's relationship history influences the personality characteristics that the parent brings to his or her adult roles. To understand who the parent is today, we have to look at who the parent was, and what the parent was doing in the years prior to parenthood. That is, we need to see the life course of the individual before parenthood. 3) Contextual variables including the immediate context and the larger context have proved to influence parental behaviors. Characteristics of the immediate context such as the quality of marital rationship can influence the parent's psychological well-being and his or her behavior toward the childen while characteristics of the larger context such as the economic situation and the neighborhood can influence the level of stress experienced by the parent and cosequently how the parent relates to his or her child. 4) In order to understand the development of the parent-child relationship we need to look at the characteristics of the child. Children may elicit positive behaviors from their parents, or they may possess characteristics that the parents find aversive thus leading to difficulties in the relationship. Therefore, much depends on the fit beween the characteristics of the parents and characteristics of the child. By examining multiple contemporaneous influences on parenting, this study could deepen the understanding of why parents have different childrearing patterns, why some parents fail to meet their children's demands and why parents act in certain ways. What we ultimately hope is that as we learn more about parenting and the development of parent-child relationships, we will be better able to provide parents with the supports they need to achieve their parenting goals.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.223-228
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• 2015

In this paper, the study of the optimum design for a geometry of the handle bar to obtain a high stiffness and light weight is investigated, using EDISON simulation program. High stiffness and weight lightening are considered as the major performance indicators of the component of the bicycle. Four design factors and three levels of the design factors are selected for the structural optimization and experiments are designed using the orthogonal array of L9 by Taguchi method. We calculated SN ratio of larger-the-better and smaller-the-better characteristics from FEA results and analysed the effects of design factors on characteristics. We choosed the optimum level of design factors based on deflection and safety factor. Comparing the results of FE analysis with converted value of predicted SN ration, we made sure for reliability of Taguchi method and FE method for structural optimization.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2395-2403
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• 2024

With the rapid development of DC high voltage accelerator, higher requirements have been raised for the design of DC high voltage power supply, requiring more stable high voltage with lower output ripple. Therefore, it also puts forward higher requirements for the parameter design of the voltage doubling rectifier circuit, which is the core component of the DC high voltage power supply. In order to obtain output voltage with better performance, the effects of the working frequency, the stage capacitance and the load resistance on the output voltage of the voltage doubling rectifier circuit are studied in detail by simulation. It can be concluded that the higher the working frequency of the transformer, the larger the stage capacitance, the larger the load resistance and the better the output voltage performance in a certain range. Based on this, a 2.5 MV voltage doubling rectifier circuit driven by a 120 kHz frequency transformer is designed, developed and tested for the power supply of the neutron source device towards BNCT. Experimental results show that this voltage doubling rectifier circuit can satisfy the design requirements, laying a certain foundation for the engineering design of DC high voltage power supply of neutron source device.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.429-436
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• 2005

In this study, we have compared with the differences between the extent of sampling disturbance and consolidation characteristics by experiments, which are consolidation test and have been performed with Kwang-Yang clay samples. The effects on sampling disturbance to consolidation characteristics of soft clay have been inverstigated by using soil samples obtained from large block sampling and piston sampling methods. Through a few experiments, we've got important results which are that the consoilidation parameter of large block sample(Pc, Cc, Cv) is much larger than the value of parameter of piston sample. We've also found the fact that the large block sample using the large size sampler is much better than piston sample in the quality of goods to lessen the effects on disturbance of sampling. When compared to the parameter of consolidation along with the methods of experiment, we found that the result performed by large size consolidation test is the greatest one and CRS is much better than standard consolidation test to seek for proper parameter.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.19-24
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• 1998

This paper aims to clarify the effects of grinding conditions on the ground surface and bending strength in surface grinding of various ferrites with diamond wheel. The main conclusions obtained were as follows. The surface roughness becomes better at lower wheel speed in the case of v/V=1$\times$10-3, and the condition of v/V=1$\times$10-4shows the best performance for the finish grinding. When the relative contact temperature becomes lower at a constant value of v/V, the ground surface exhibits lower roughness. The ground surface shows that the fracture process during grinding becomes more brittle at the higher value of v/V. The damage depth which affect the bending strength is below 10$\mu$m in the grinding condition of S=10㎣/mm.s with the diamond tool after dressing & truing, however, the depth increases with increasing removal rate(S). When the strength degradation due to grinding is larger, the removal depth for the recovery of strength requires a larger size.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1072-1074
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• 1993

The superconducting generator has better efficiency, larger power, higher voltage, bigger power per weight ratio and bigger power per volume ratio than conventional machines. Furthermore, for the synchronous reactance of the superconducting generator is smaller than that of conventional ones, the capacity of power transfer is much larger than conventional machina. But, the low inertia constant of superconducting generator hurts the transient stability of power system. This paper deals with the comparisons of transient characteristics between superconducting generator and conventional generator by computer simulation.

• Journal of Families and Better Life
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• v.5 no.2
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• pp.65-82
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• 1987

Product characteristic approach and hedonic method were explained and applied to demand behavior of housing for 360 households sampled from four districts of Seoul. Th major findings are: 1) Housing prices are determined by housing characteristics, i.e., basic structure, interior space, interior quality, and neighborhood quality. 2) as income increase , the demand for basic structure, interior space, interior of quality, and neighbor hood quality increases. As compared to the counties that have advanced housing financial systems, income elasticity form housing characteristics was low. 3) householder's educational level has insignificant effects on the demand for neighborhood quality. 4) the housing need of family is different to a family life cycle. In the first stage, the increase of income enhances the demand for basic structure. interior space, and interior quality, but inversed with neighborhood quality. In the second and third stages, the demand for basic structure, interior space, and interior quality increases as the income increases. 5) It is predicted that the larger the family size, the more housing space is required. But in the low-income group, an increase in family size results in a decrease in the demand for interior space because expenses for food and education are indispensable ones. In the middle -income group the demand for interior space, interior quality increases as the family size increases, In the high-income group, the larger the family size the more interior quality is demanded. As mentioned above, the demand for housing is derived form characteristics and the demand behavior far housing characteristics is varied with individual household's characteristics. Therefore, the fact that different housing needs according to various income groups should be considered in housing policy.

• Journal of the Korean Society of Safety
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• v.18 no.1
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• pp.28-32
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• 2003

The present study investigates the spray characteristics of water mist nozzle with mid-low pressure for fire suppression. The examined nozzle types are swirl and spiral nozzle. The result shows that K factor of water mist nozzle is much smaller than those of general sprinkler. Spray angle of spiral nozzle is largest and more than $150^{\circ}$. SMD(Sauter Mean Diameter) of water mist nozzles is ranged between 100 and 200$\mu\textrm{m}$through measuring by image processing method. The spray pattern of spiral nozzle represent that water flux of first stream is 2 times larger than that of second stream. This study will contribute better understandings of the water-mist spray characteristics and useful daia for developing the water-mist nozzles.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.10
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• pp.953-959
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• 2006

Langmuir-Blodgett(LB)layers of Arachidic acid deposited by LB method were deposited onto slide glass as Y-type film. The structure of manufactured device is Au/arachidic acid/Al, the number of accumulated layers are $9{\sim}21$. Also, we then examined of the Metal-Insulator-Metal(MIM) device by means of I-V. The I-V characteristics of the device are measured from -3 to +3 V. The insulation property of a thin film is better as the distance between electrodes is larger.