• Journal of Korean Academy of Nursing
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• v.25 no.2
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• pp.244-258
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• 1995

아기의 출생은 부모에게 환경적, 신체적, 정신적 부담을 준다. 이렇게 부모가 된 사람들은 부모역할 수행시 어려움을 겪고 있고, 그 중에서도 어머니가 아버지보다 역할수행시 더 많은 어려 움을 겪고 있다고 한다. 본 연구는 생후 8개월 된 아기 어머니들을 대상으로 역할이 론을 토대로 모성역할 획득에 영향을 주는 요인들로 가설적 모형을 구축하고, 이의 적합성을 검정하므로 써 어머니들의 모성역할 획득을 촉진하기 위하여 필요한 간호 정보를 제공하려고 한다. 본 연구는 문헌고찰을 통하여 모성역할 긴장과 모성역할 획득에 영향을 주는 요인으로 일상생활의 시간적 여유, 아기 기질, 사회적 지지가 포함되었고, 모성역할 긴장이 모성역할 획득에 영향을 주는 것으로 이론적 기틀을 구성하였다. 연구도구로는 모성역할 획득 중 모성 정체감을 측정하기 위해 Osgood(Walker et al., 1986a에서 인용)도구, 모성역할 수행을 측정하기 위해 수정보완 된 Gibaud-Wallston(1977)도구와 어머니가 지각한 모아 상호작용정도 도구를 이용하였고, 모성역할 긴장측정에는 수정 보완된 Hobbs(정, 1985에서 인용)도구를 이용하였다. 아기 기질은 수정 보완한 The degree of thor inventory(Mercer, 1986 에서 인용), 남편의 정신적지지 측정은Taylor(Durrett, 1986에서 인용)의 도구를 이용하였고, 일상생활의 시간적 여유, 남편의 신체적 지지 및 주위의 지지측정은 연구자가 개발한 도구를 사용하였다. 1993년 1월부터 1994년 1월까지 대전시 5개 보건소에 등록된 대상자들에게 우편으로 설문지를 보내어 221명이 회수되어 회수율이 약72%였다. 일반적인 서술적 자료 분석은 SPSS PC+ 를 이용하였고, 가설적 모형은PC-LISREL 7.13 (Joreskkog & Sorbom,1988)프로그램을 이용하여 공변량구조분석을 하였다. 연구결과는 다음과 같다. 모성역할 획득에 모성역할 긴장, 일상생활의 시간적 여유, 아기 기질, 사회적 지지가 영향을 주며, 모성역할 긴장에는 일상생활의 시간적 여유, 아기 기질, 사회적지지가 영향을 준다고 설정된 가설적 모형〈Figure 1〉의 분석 결과 전반적 지수는 자유도 23에 카이자승치 60.17, GFI와 AGFI의 값은 .944, .891였고, NFI와 NNFI의 값은 .8823, .7932 이었다. 그러나 세부적 지수 중 모성역할 긴장에서 모성역할획득으로의 경로, 일상생활의 시간적 여유에서 모성역할 획득으로의 경로, 아기 기질에서 모성역할 획득으로의 경로의 고정지수가 절대치 2에 미치지 못하여, 세 경로계수를 영(0)으로 고정시킬 필요가 있었다. 따라서 더 간명하며 부합도가 좋은 모형을 찾기 위하여 가설적모형에서 고정지수가 낮은 경로 부터 고정시켜 나가 세경로(모성 역할 긴장에서 모성역할 획득, 일상생활의 시간적 여유에서 모성역할 획득, 아기 기질에서 모성역할획득)를 고정시킨 수정 모형 의 PFI (간명도)가 .5986으로서 가설적모형의 PFI(간명도) .5636보다 커 부합도 를 손상하지 않고 더 간명한 모형으로 나타났다. 수정모형 의 고정 지수를 살펴 본 결과 절대 치 2에 미치지 못하는 경로는 나타나지 않았다. 공변량구조분석 결과 나타난 변인간의 관계를 보면 가) 모성역할 긴장은 사회적 지지가 많을수록(Lisrel Estimates=-1.591), 아기 기질이 순하다고 생각할수록(Lisrel Estimates=-.266), 일상생활의 시간적 여유가 많을수록(Lisrel Estimstes=-1.771) 낮았고, 나) 모성역할 획득은 사회적 지지가 많을수록(Lisrel Estimates=1.120) 잘 되었다.

• Journal of the Korean Society for Railway
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• v.19 no.3
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• pp.331-340
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• 2016

Wheel load, design velocity, traffic amount (MGT), stiffness and thickness of sub-layers of asphalt concrete track are selected as performance design parameters in this study. A pseudo-static wheel load computed considering the dynamic amplification factor (DAF) based on the design velocity of the KTX was applied to the top of asphalt concrete track for full three dimensional structural analysis using the ABAQUS program. Tensile strains at the bottom of the asphalt concrete layer and vertical strains at the top of the subgrade were computed from the structural FEA with different combinations of performance parameter values for one asphalt concrete track section. Utilizing the computed structural analysis results such as the tensile strains and the vertical strains, it was possible to develop design graphs to investigate proper track sections for different combination of the performance parameters including wheel load, design velocity, traffic amount(MGT), stiffness and thickness of asphalt concrete layers for any given design life. By analyzing the proposed design graphs for asphalt concrete track, it was possible to propose simple design tables that can be used by engineers for the effective and fast design of track.

• Journal of Radiation Protection and Research
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• v.22 no.1
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• pp.1-7
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• 1997

Radiation protection by post-irradiation injection of the ginseng extract in mice was studied. Male ICR mice, 7 weeks old, were orally injected with ginseng extrat(100mg/kg) for 10 days, and with physiologocal saline as the control. Immediately after final injection, mice were whole body irradiated with 5.08Gy(Cs-137 ${\gamma}$-ray, central dose rate : 654Gy/h) which induced Bone marrow death. At 24h after irradiation, micronucleus test and metaphase analysis in bone-marrow were carried, blood cell were counted and the survival rate were carried for 30 days after the irradiation. Stimulated recovery by the extract was observed in thrombocyte count, but that phenomenom was not showed in the erythrocyte and leucocyte counts. The 30-day survival ratio was 5% and 65% for the control and experimental group. Frequencies of micronuclei per 1000 polychromatic erythrocytes were 79.5${\pm}$1.5 in experimental group, 185.9${\pm}$35.8 in control. And Abnormal chromosomes per 50 metaphases were 112 in experimental group and 143 in control.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.2
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• pp.136-143
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• 2013

In the sewage structures and wastewater facilities, concrete is exposed to hydrogen sulfide ($H_2S$) which acts as an acid material in a solution, and a strongly acidic sulfate ion ($SO{_4}^{-2}$) is generated by a sulfuric bacteria. Hence, a degradation of concrete with biochemical corrosion would be accelerated. Finally, durability of concrete and concrete structures may be greatly reduced. In this study, in order to remove the hydrogen sulfide which is used by the sulfuric bacteria organic-biologically, the antibiotic metal and metallic salt powders were mixed to concrete, and a suppressing performance of the sulfate ion was assessed. For the sulfuric acid bacteria, a comparative evaluation of antimicrobial performance on neutralized concrete specimens were carried out, also by a rapid chloride penetration test, chloride penetration depths and diffusion coefficients were measured for antibiotic concrete in accordance with the amount of metal and metallic salt-based antibacterial agents. Eventually, by an observation of the biochemical state of the surface of concrete specimens exposed outdoors, the performance and applicability of antibiotic concrete were confirmed.

• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.183-192
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• 2008

Stone cultural heritages in Korea are mostly situated out door without any notable protection thus there are severe damage from chemical and biological weathering. This in turn, causes deformation and structural damage. To counter act this problem and to increase durability, various kinds of conservation materials are used in the conservation and restoration treatment. However, there are not many practical and technological experiment done on this subject. This paper attempts quantitative evaluation of effectiveness of ethylsilicate based resin for Namsan granite in Gyeongju. When two different materials with different ethylsilicate concentration were compared, the result indicated decrease of absorption and porosity with increase of ultrasonic velocities, uniaxial compressive strength, elastic constant, tensile strength and Poisson's ratio. In addition, comparison of physical characteristic of the conservation material resulted favorably toward ones with higher concentration of ethylsilicate. This is due to the ethylsilicates characteristic to fill the internal pores of stone. There is discolouration of stone surface after treatment with conservation material. This was more prominent with the product of higher ethylsilicate concentration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.37-43
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• 2017

This review investigates the basic principle of physical interactions and failure mechanisms introduced in the materials and inner parts of semiconducting components under electromagnetic pulses (EMPs). The transfer process of EMPs at the semiconducting component level can be explained based on three layer structures (air, dielectric, and conductor layers). The theoretically absorbed energy can be predicted by the complex reflection coefficient. The main failure mechanisms of semiconductor components are also described based on the Joule heating energy generated by the coupling between materials and the applied EMPs. Breakdown of the P-N junction, burnout of the circuit pattern in the semiconductor chip, and damage to connecting wires between the lead frame and semiconducting chips can result from dielectric heating and eddy current loss due to electric and magnetic fields. To summarize, the EMPs transferred to the semiconductor components interact with the chip material in a semiconductor, and dipolar polarization and ionic conduction happen at the same time. Destruction of the P-N junction can result from excessive reverse voltage. Further EMP research at the semiconducting component level is needed to improve the reliability and susceptibility of electric and electronic systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.539-547
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• 2017

This study examined the perception of disasters and post-traumatic stress disorder in occupational therapy majors to provide the basic data necessary for future occupational therapy. A questionnaire survey was conducted on 545 students in occupational therapy departments of three year and four year universities. The frequency of the questionnaire was calculated by frequency analysis using the SPSS 19.0 win program. A chi-squared test was conducted to verify the analyzed questionnaire data. The reliability of the questionnaire in this study showed a Cronbach' alpha value of 0.891. According to the survey results, approximately 20% of learners who majored in occupational therapy were unaware of the symptoms, developmental mechanism, and diagnostic criteria of post-traumatic stress disorder(PTSD). Knowledge of the underlying causes of psychological symptoms, such as post-traumatic stress disorder as well as physical damage through industrial accidents, was found to be 2.92 on the Likert 5-point scale. To be effective in rehabilitation treatment, the degree of the approach to education from the viewpoint of occupational therapy is important enough to be recognized as 3.90 on the Likert 5-point scale. The Pearson correlation coefficient for the need for education on disasters was higher than the correlation with the awareness of disasters.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.393-399
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• 2017

In a reciprocating compressor, the piston and connecting rod are important parts. Excess mechanical stress on these parts may cause damage, and broken parts are expensive and difficult to replace. Therefore, it is necessary to analyze the mechanical stress affecting durability and longevity. The main purpose of this study was to identify locations of maximum stress on pistons and connecting rods. Based on dynamic calculation of the working process of a specific air compressor, an analysis of piston and connecting rod performance has been completed. A three-dimensional model for the air compressor's pistons and connecting rods was built separately, and FEM analysis of these components was carried out using a numerical method. The pistons were loaded by pressure which was changed according to crankshaft angle without thermal boundary conditions. The simulation results were used to predict and estimate stress concentration as well as the value of this stress on pistons and connecting rods. The maximum equivalent stress calculated are over 190 MPa on pistons and 123 MPa on connecting rods at crank angle $135^{\circ}$ and $225^{\circ}$ but these are under tensile yield strength. Besides, the calculated safety factors of connecting rods and pistons is higher than 1. Moreover, the results obtained can be used to provide manufacturers with references to optimize the design of pistons and connecting rods for reciprocating compressors.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1774-1778
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• 2008

유량 환산에 이용되는 수위-유량 관계곡선식은 하천의 흐름을 정상 등류상태로 가정하고 유속계를 하천에 투입하여 년간 정해진 횟수의 유량측정을 실시하여 이로부터 갱신하여 작성하고 있다. 평수기에는 이렇게 기기를 이용하여 유량측정이 가능하지만 홍수기나 갈수기에는 접촉식 유속계를 이용한 하천유량 측정이 불가능한 실정이다. 홍수기에는 기기 손상과 관측자의 안전이 위협받는 실정이고, 갈수기에는 유속이 너무 느려서 (0.1 m/s 이하) 프로펠러 유속계의 경우 유속의 정확한 관측이 힘들다. 또한 전지구적 빈번한 이상기후의 현실정에서 가장 중요한 기초 수문자료인 홍수량의 정확한 측정 자료는 많지 않다. 홍수유량을 측정하기 위해서 현재에도 기존의 봉부자를 이용하거나 유비쿼터스 센서를 장착한 봉부자를 이용하는 유량측정 기법이 향해지고 계속적으로 소개되고 있는 실정이지만 봉부자의 특성상 정확한 유량을 계산하기에는 어려움이 많다. 현재 선진국에서는 흐름과 비접촉식 방법을 이용한 하천유량측정 방법이 지난 10 여년간 꾸준이 연구되어 왔다. 그중 대표전인 것이 전자파를 이용한 방법과 영상해석에 의한 방법이다. 전자의 경우 국내에서는 수자원공사에서 10년 이상 연구 개발하여 상품화 시킨바 현업에서 이를 이용하여 홍수유량측정을 실시하고 있다. 후자의 방법은 유체역학 분야에서 흐름해석에 주로 이용되어지던 PIV(particle image velocimetry) 기법을 하천과 같이 대규모의 흐름영역에 적용가능하도록 개발된 기술로 LSPIV (large-casle particle image velocimetry)라 불리우는 기술이다. 본 연구에서는 미국 Iowa 대학에서 개발한 LSPIV를 이용하여 홍수파의 진행시 수위와 유량의 두 변수 사이에 나타나는 Loop rating curve의 이론적인 관계를 하천현장에서 일정시간 간격으로 실측을 통하여 파악하고자 하였다. 현장실험을 위한 대상지점으로 미국 Iowa주 Coralville 시내 Clear Creek의 USGS (US Geologival Survey) 수위관측소 지점을 선택하여 본 연구에서 실시한 유량측정 결과의 비교가 가능토록 하였다. LSPIV는 그 특성상 야간에는 적용하는데 어려움이 있어 아침시간부터 해가 지기 직전까지의 자연채광 조건의 영상취득이 가능한 시간대에서 표면유속을 측정하였고 이에 수심평균유속환산계수를 적용하여 유량을 계산하였다. 강우의 발생으로 인한 홍수파의 진행시 총 43회의 유량을 측정하였는바 이를 이용하여 이 지점의 수위-유량 관계식과 비교한 결과 거의 일치하는 결과를 나타냈다. 특히 홍수파의 진행시 고수위 영역에서의 측정한 결과는 수위의 상승기에는 최고로 7.5% 까지 측정유량이 수위-유량관계식에서 계산한 유량보다 컸으며, 수위의 하강기에는 반대로 최고 5.4% 정도까지 측정유량이 수위-유량관계식에서 계산한 유량보다 작게 나타났다. 또한 최대유량의 발생시기는 최고수위 발생직전의 수위라는 것이 파악되었다. 이러한 경향은 수위-유량 관계곡선의 이론과 잘 일치하는 것이다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.437-450
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• 2014

In this study, we developed a methodology to determine the reference parameter for an aircraft impact induced risk assessment of nuclear power plant (NPP) using finite element impact analysis of containment building. The target structure used to develop the method of reference parameter selection is one of the typical Korean PWR type containment buildings. We composed a three-dimensional finite element model of the containment building. The concrete damaged plasticity model was used for the concrete material model. The steels in the tendon, rebar, and liner were modeled using the piecewise-linear stress-strain curves. To evaluate the correlations between structural response and each candidate parameter, we developed Riera's aircraft impact force-time history function with respect to the variation of the loading parameters, i.e., impact velocity and mass of the remaining fuel. For each force-time history, the type of aircraft is assumed to be a Boeing 767 model. The variation ranges of the impact velocity and remaining fuel percentage are 50 to 200m/s, and 30 to 90%, respectively. Four parameters, i.e., kinetic energy, total impulse, maximum impulse, and maximum force are proposed for candidates of the reference parameter. The wellness of the correlation between the reference parameter and structural responses was formulated using the coefficient of determination ($R^2$). From the results, we found that the maximum force showed the highest $R^2$ value in most responses in the materials. The simplicity and intuitiveness of the maximum force parameter are also remarkable compared to the other candidate parameters. Therefore, it can be concluded that the maximum force is the most proper candidate for the reference parameter to assess the aircraft impact induced risk of NPPs.