입자 크기별 가공부산물로 제조된 벌크흑연의 기계적 성질

이상혜,이상민,장원표,노재승 한국분말야금학회 2021 한국분말재료학회지 (KPMI) Vol.28 No.1

Bulk graphite is manufactured using graphite scrap as the filler and phenolic resin as the binder. Graphite scrap, which is the by-product of processing the final graphite product, is pulverized and sieved by particle size. The relationship between the density and porosity is analyzed by measuring the mechanical properties of bulk graphite. The filler materials are sieved into mean particle sizes of 10.62, 23.38, 54.09, 84.29, and 126.64 μm. The bulk graphite density using the filler powder with a particle size of 54.09 μm is 1.38 g/cm3, which is the highest value in this study. The compressive strength tends to increase as the bulk graphite density increases. The highest compressive strength of 43.14 MPa is achieved with the 54.09 μm powder. The highest flexural strength of 23.08 MPa is achieved using the 10.62 μm powder, having the smallest average particle size. The compressive strength is affected by the density of bulk graphite, and the flexural strength is affected by the filler particle size of bulk graphite.

부사관의 직무스트레스 정도에 따른 빗속의 사람그림검사 반응특성

이상혜,이근매 한국예술심리치료학회 2014 예술심리치료연구 Vol.10 No.3

본 연구의 목적은 부사관의 직무스트레스 정도에 따른 빗속의 사람그림검사의 반응특성은 어떠한가를 알아보고, 빗속의 사람그림검사가 부사관의 직무스트레스를 진단하는 보완적 도구로써 활용가능성이 있는지 알아보고자 하였다. 연구대상은 G시에 소재한 육군부대 2곳, K시에 소재한 육군부대 2곳에 복무 중인 부사관으로 268명이다. 연구도구는 직업군인의 직무스트레스척도와 빗속의 사람그림검사를 사용하였다. 자료처리는 SPSS WIN 20.0 프로그램을 사용하여 빗속의 사람그림검사의 반응특성은 어떠한가를 알아보기 위해 직무스트레스척도 점수를 기준으로 상위군과 하위군으로 분류하여 t-test를 실시하였으며, 개인변인에 따른 반응특성은 어떠한가를 알아보기 위해 t-test와 일원변량분석(one-way ANOVA)을 실시하고, 사후검증으로 Scheff'e test를 실시하였다. 본 연구의 결과를 요약하면 다음과 같다. 첫째, 직무스트레스 정도에 따른 빗속의 사람그림검사에서 유의한 차이가 나타났다. 둘째, 결혼여부에 따른 빗속의 사람그림검사의 대처자원영역에서 기혼인 군인들이 미혼인 군인들에 비해 대처자원영역이 더 높게 나타났으며, 종교에 따른 빗속의 사람그림검사에서 무교를 가진 군인이 불교를 가진 군인에 비해 스트레스가 더 높고, 대처자원영역은 더 낮은 것으로 나타났다. 이러한 연구결과는 빗속의 사람그림검사가 부사관의 직무스트레스를 측정하고 진단하는 보완적 도구로서의 활용가능성을 시사한다. This study is intended to investigate the reaction characteristics of Person In The Rain(PITR) drawing test in relation to the degree of non-commissioned officers'(NCOs) job stress. This is also meant to figure out if PITR drawing test is useful as a supplementary tool for diagnosing job stresses of professional soldiers. 268 NCOs who serve 2 army bases in K city and 2 army bases in G city, are subjected to this study. As for the data processing, in order to investigate about how the reaction characteristic of PITR drawing test according to the degree of job stress was using SPSS WIN 20.0 program, t-test was performed by classifying on upper group and lower group based on the job stress criteria score and in order to investigate about how the according to individual variables it were performed t-test and one-way ANOVA analysis, and Scheff'e test was performed as the post-verification. The summary of the result is following: First, there was a significant difference in the t-test score of PITR according to the degree of job stress. Second, of individual variables, the marital status gives a certain difference to PITR drawing test. Married soldiers showed higher coping resource scope than unmarried ones. Religion was another factor. The soldiers with no religion showed higher job stress level and lower coping resource scope than those with Buddhism. This study implies that PITR drawing test is valid to measure the job stress level of NCOs and can be used as a supplementary diagnostic tool.

XRD와 마이크로 라만 분석을 이용하여 700 oC 공기 중에 서 등온 산화된 PAN계 탄소섬유의 미세구조 변화 해석

이상혜,오성문,이상민,노재승 한국섬유공학회 2021 한국섬유공학회지 Vol.58 No.1

In this study, isothermal oxidation reactions of polyacrylonitrile-based T300 andT700 carbon fibers were conducted in air at 700 °C by employing a horizontal tube furnace. The oxidized fibers were examined through XRD and micro-Raman analysis for quantitativelyanalyzing the changes in crystallinity occurring after the oxidation reactions. Theresults obtained from XRD analysis corroborate that the overall crystallinity of an oxidizedfiber is lower than that of the corresponding raw fiber. Observation through a scanningelectron microscope indicates that a longitudinal hollow pore is formed along the fiber axisof each oxidized fiber. Additionally, since the crystallinity of the fiber core is lower than thatof the sheath, the conducted micro-Raman analysis suggests that the core became oxidizedfirst to form the longitudinal hollow pore. In this study, it was difficult to measure thedepth of the longitudinal hollow pore through the fiber core. In the future, if the depth ofthe hollow pore can be measured at the fiber core and is optimized for developing the hollowpore, new support materials, which serve as the carriers, can be designed.

일본에 있는 교포 어린이들에게

이상혜 한국국어교육학회 1995 세계가 한동네 Vol.1995 No.-

원자력발전소의 안전성

이상혜 대한전기협회 1980 대한전기협회지 Vol.- No.48

인산형 연료전지(PAFC) 분리판용 천연흑연/고분자복합재료 제조 시 카본블랙 첨가량에 따른 전기전도도와 강도 변화

이상혜(Sang-Hye Lee),김효창(Hyo-Chang Kim),노재승(Jae-Seung Roh) 한국정보기술학회 2021 Proceedings of KIIT Conference Vol.2021 No.6

한국(韓國)에 있어서의 출생순위(出生順位)의 변화(變化) : 1975~1984

이상혜 ( Sang Hun Lee ) 한국보건사회연구원 1988 保健社會硏究 Vol.8 No.2

本 硏究는 지난 1975年부터 1984年까지 申告된 出生順位에 따른 出生兒數의 變化趨勢를 分析한 것이다. 分析에 活用된 資料는 ``1985年 人口動態 申告``로써, 分析은 다음과 같은 事項들이다. 첫째, 1975年부터 1984年까지 出生順位에 따른 出生兒들의 百分率과 平均出生順位의 變化趨勢를 살펴보았다. 둘째, 1975年부터 1984年까지 地域別 出生順位에 따른 出生兒들의 百分率과 平均出生順位의 變化趨勢를 地域別로 比較 分析하였다. 세째, 1975年부터 1984年까지 母의 年齡別 出生順位에 따른 出生兒들의 百分率과 平均出生順位의 變化趨勢를 比較 分析하였다. 硏究結果를 보면, 1975年부터 1984年 사이에 平均出生順位는 繼續해서 떨어져왔으며, 大都市의 平均出生順位는 他 市ㆍ道의 그것보다 繼續 낮은 水准을 維持해 왔으나 兩地域의 平均出生順位 差異는 時間이 經過함에 따라 차츰 좁혀지는 傾向을 보여왔다. 그리고 母의 年齡別로 分析해 보았을 때, 母의 年齡이 15歲에서 24歲까지에 속하는 集團은 지난 10年間(1975~1984)平均出生順位가 큰 變化없이 繼續해서 비슷한 樣相을 보였으나, 母的 年齡이 30歲이상에 속하는 集團에서는 같은 期間동안에 平均出生順位가 繼續해서 떨어지는 樣相을 보였다. 지난 10年間 出生順位에 따른 出生兒數의 百分率을 보면 첫째아와 둘째아로 繼續해서 集中되는 樣相을 보였으며, 出生兒들의 대부분이 母의 年齡이 20歲에서 29歲에 속하는 集團으로 集中되어 일어나고 있는 樣相을 보였다.

Changes in Physical Properties with Varying Impregnation Temperatures and Compression Times During Fabrication of Carbon Blocks Using Needle Cokes and Pitch

윤우상,이상혜,김종복,노재승 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.7

Impregnation was conducted to decrease the pores formed during the carbonization process after manufacturing carbon blocks using needle cokes and coal tar pitch. This was carried out in the order of heating, subjecting to vacuum, and compression, and changes in mechanical and electrical properties before and after impregnation were analyzed with impregnation temperature and compression time as variables. The impregnation temperatures were 150, 200, and 250 °C, and compression times were 30, 60, and 90 min. The optimal impregnation temperature was 200 °C, resulting in a 12.5% increase in bulk density and a 26.0% decrease in porosity after impregnation of the carbon blocks. The optimal compression time was 60 min, leading to a 14.3% increase in bulk density and a 24.0% decrease in porosity after impregnation. Under the selected optimal conditions, after three impregnation cycles, the bulk density increased by 33.8% compared to the initial state (0 cycles 1.259 g/cm 3 → 3 cycles 1.685 g/cm 3 ), and porosity decreased by 56.8% (0 cycles 39.1% → 3 cycles 16.9%). According to the performance evaluation of carbon blocks, electrical resistivity decreased by 52.0% (72.5 μΩm → 34.8 μΩm) and fl exural strength increased by 368.3% (6.0 MPa → 28.1 MPa). The substantial increase in fl exural strength was attributed to the reduction in porosity.

일축가압법으로 벌크흑연 제조 시 성형압력에 따른 열린기공률 변화가 함침 후 밀도 향상에 미치는 영향

이상민,이상혜,노재승 한국분말야금학회 2021 한국분말재료학회지 (KPMI) Vol.28 No.1

The change in the open porosity of bulk graphite as a function of the uniaxial molding pressure during manufacturing is studied using artificial graphite powder. Subsequently, the graphite is impregnated to determine the effect of the open porosity on the impregnation efficiency and to improve the density of the final bulk graphite. Bulk graphite is manufactured with different uniaxial molding pressures after mixing graphite powder, which is the by-product of processing the final graphite products and phenolic resin. The bulk density and open porosity are measured using the Archimedes method. The bulk density and open porosity of bulk graphite increase as the molding pressure increases. The open porosity of molded bulk graphite is 25.35% at 30 MPa and 29.84% at 300 MPa. It is confirmed that the impregnation efficiency increases when the impregnation process is performed on a specimen with large open porosity. In this study, the bulk density of bulk graphite molded at 300 MPa is 11.06% higher than that before impregnation, which is the highest reported increase. Therefore, it is expected that the higher the uniaxial pressure, the higher the density of bulk graphite.

함침재의 점도에 따른 벌크흑연의 기공 채움 효과

이상민,이상혜,노재승 한국재료학회 2021 한국재료학회지 Vol.31 No.2

Pores produced by carbonization in bulk graphite process degrade the mechanical and electrical properties of bulk graphite. Therefore, the pores of bulk graphite must be reduced and an impregnation process needs to be performed for this reason. In this study, bulk graphite is impregnated by varying the viscosity of the impregnant. The pore volume and pore size distribution, according to the viscosity of the impregnant, are analyzed using a porosimeter. The total pore volume of bulk graphite is analyzed from the cumulative amount of mercury penetrated. The volume for a specific pore size is interpreted as the amount of mercury penetrating into that pore size. This decreases the cumulative amount of mercury penetrating into the recarbonized bulk graphite after impregnation because the viscosity of the impregnant is lower. The cumulative amount of mercury penetrating into bulk graphite before impregnation and after three times of impregnation with 5.1cP are 0.144 mL/g and 0.125 mL/gm, respectively. Therefore, it is confirmed that the impregnant filled the pores of the bulk graphite well. In this study, the impregnant with 5.1 cP, which is the lowest viscosity, shows the best effect for reducing the total pore volume. In addition, it is confirmed by Raman analysis that the impregnant is filled inside the pores. It is confirmed that phenolic resin, the impregnant, exists inside the pores through micro-Raman analysis from the inside of the pore to the outside.