• Journal of the Korean Ceramic Society
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• v.37 no.9
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• pp.921-926
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• 2000

에틸렌과 프로판가스로부터 Ni 및 Ni-Cu의 합금촉매를 사용하는 화학증착반응에 의해 제조한 나노탄소섬유에 충전재로 하고, 환경 친화적인 폴리비닐알코올을 매트릭스로 이용하여 복합재를 제조하여 전자파 차폐효능을 조사해 보았다. 전자파 차폐용 충전재의 중요한 물성치인 전기전도도는 나노탄소섬유의 반응조건에 따라 매우 민감하게 변했는데, 전체적으로 10000 psi 압력에서 4.2~29 S/cm 사이에 분포하였고 합금촉매보다도 순수한 Ni로 제조된 나노탄소섬유의 전기전도도 값이 높았다. 한편, 나노탄소섬유/폴리비닐알코올 복합재의 전기전도도는 Ni:Cu(7:3) 합금촉매에서 제조된 나노탄소섬유를 충전시켰을 때, 가장 높게 얻어져서 충전재의 전기전도도 외에도 비표면적이 중요한 변수임을 알 수 있었다. PVA 양에 대한 나노탄소섬유의 함량이 증가할수록 나노탄소섬유 복합재의 전기전도도는 기하급수적으로 증가했고, 110$0^{\circ}C$에서 1시간 동안 나노탄소섬유의 열처리를 통하여 복합재의 전기전도도는 5~7배 증가하였으며, 전자파 차폐율은 2~3 dB 정도 향상시킬 수 있었다.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.60-61
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• 1994

복합막은 기존의 비대칭막에 비해서 극히 얇은 표면층을 형성할 수 있다. 이러한 복합막은 배제율도 우수할 뿐만아니라 투과속도 또한 매우 큰 특징을 가지고 있으며, 해수의 담수화를 비롯하여 초순수 제조 등 각종 산업분야에서 많이 응용되고 있다. 우수한 분리막을 제조하기 위해서는 막의 표면층을 보다 더 치밀하고 얇게 형성할 수 있어야 한다. 이렇게 하기 위해서는 지지막 또한 매우 중요한 요인으로 작용한다. 표면층이 치밀하고, 가능한 한 porosity가 큰 지지막을 제조해야한다. 따라서 본 연구에서는 고분자 물질로 Polyethersulfone을 사용하여 지지막을 만들었다. 이 지지막위에 계면중합법으로 NF/RO용 복합막을 제조하였다. 높은 투과 속도 및 염의 배제율이 우수한 복합막을 제조하기 위해서 먼저 Polymer 농도, 첨가제 종류및 농도 등에 의한 각종 제막조건에 따른 지지막의 성능을 조사하였다. 여기에 Monomer 농도를 변화시켜서 계면중합으로 복합막을 제조하여 그 성능 변화를 측정하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.219-220
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• 2007

실란 커플링제 종류에 따른 $SrTiO_3$/유기물 복합재료의 유전특성에 미치는 영향을 조사하여 비교하였다. 실란 커플링제는 amino계, epoxy계, methacryloxy계, acryloxy계, vinyl계를 사용하였으며, tape casting 방법으로 제작한 복합체 필름을 vacuum lamination 공정을 통하여 기판을 만들어 유전특성을 측정하였다. 실란 괴플링제의 종류에 따라 유전특성은 상이한 결과를 나타냈으며, acryloxy계를 제외한 다른 커플링제를 처리한 복합재료는 유전상수와 유전손실이 감소하는 경향을 확인할 수 있었다. Acryloxy계 커플링제를 처리한 복합재료는 커플링제가 처리되지 않은 복합재료와 비교하여 유전상수가 6%정도 증가하였며, 유전손실은 25%정도 감소하였다.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2023.11a
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• pp.341-342
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• 2023

본 연구는 초고층 및 지하연계 복합건축물이 증가하여 재난에 취약성이 높아짐에 따른 재난대응 반안에 관해 연구를 진행했다. 사회재난과 자연재난 중 건축물에 영향을 미치는 재난을 국내외 사례와 문헌조사를 통해 도출하고 각 재난의 공통된 취약성과 개별적 취약성을 찾았으며, 재난유형별 복합재난 시나리오를 선정하였다. 초고층 및 지하연계 복합건축물의 위험성이 높아지면서 소방청은 재난예방 및 피해경감 계획 수립 세부지침서를 만들었지만, 한정적인 재난과 구체적 예시의 부재로 미흡한 상태이다. 따라서 앞서 제시한 재난의 재난대응 방안을 만들어 재난대응흐름도를 작성하여 실제적인 대응 방안을 수립하고자 한다.

• Resources Recycling
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• v.19 no.4
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• pp.51-57
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• 2010

As a recycling of Si sludge from Si wafer process, a Si-SiC-CuO-C composite material was synthesized and investigated as an anode material for lithium batteries. The Si sludge consisted of Si, SiC, machine oil, and metallic impurities. The oil and metal impurities was removed by organic washing, magnetic separation, and acid washing. The Si-SiC-CuO-C composite from the recovered Si-SiC mixture was prepared by high-energy mechanical milling. According to the electrochemical tests such as charge-discharge capacity and cycling behavior, it showed the improved cycle performance. The SiC and CuO-related phases were presumed to restrain the volume expansion of the anode and Fe, however, should be removed below 10 ppm prior to synthesis of the composite because it caused the capacity loss of the active material itself.

• Membrane Journal
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• v.13 no.4
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• pp.291-299
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• 2003

Polymer membranes such as poly(1-trimethylsilyl-1-propyne)-polyetherimide (PTMSP-PEI) and poly(dimethylsiloxane)- polyetherimide (PDMS-PEI) composite membrane were prepared by solution casting method. To investigate the characteristics of these membranes, the analytical methods such as FT-IR, $^1H-NMR,$ DSC, TGA, GPC, and SEM have been utilized. The number-average (equation omitted) and weight-average (equation omitted) molecular weight of PTMSP were 477,920 and 673,329 respectively. The glass transition temperature ($T_g$) of PTMSP was $224^{\circ}C.$ The separation of the gas mixture ($H_2/N_2$) through the composite membranes were studied as a function of pressure. The separation factor (${\alpha}, {\beta},$ quation omitted) of the composite membranes used in this work increased as the pressure of permeation cell increased. The real separation factor (${\alpha}$), head separation factor (${\beta}$), and tail separation factor (equation omitted) of PTMSP-PEI composite membrane were 2.28, 1.17, and 1.96 respectively at ${\Delta}P$ 30psi and $25^{\circ}C.$ (${\alpha}, {\beta}$ and equation omitted of PDMS-PEI composite membrane were 3.70, 1.53, and 2.42 respectively at ${\Delta}P$ 30psi and $25^{\circ}C$.

• Membrane Journal
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• v.14 no.1
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• pp.57-65
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• 2004

The effect of porous support layer resistance and PDMS (polydimethylsiloxane) coating thickness on ethylene/nitrogen separation of composite membranes was studied with the model of Pinnau and Wijmans〔1〕. To control the support resistance (or permeance), PES porous membranes were prepared by phase inversion process with various PES/NMP dope concentrations. The thickness of selective PDMS top layer was controlled by using a spin coater. Its cross-section and coating thickness were observed by scanning electron microscope (SEM). Pure gas permeation test was done with ethylene and nitrogen, respectively. The experimental result for olefin/nitrogen separation process matched well with theoretical result from the model used. The result shows that optimization between PDMS coating thickness and support resistance is important to get PDMS composite membranes with best performance.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.75-82
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• 2019

Many people suffers from multiple chronic diseases, leading cause of death and disability in the world. The purpose of this study was to investigate factors affecting multiple chronic diseases, hypertension, and diabetes. We analyzed the data of one metropolitan city of community health survey, 2015. 4,590 citizens were enrolled in this study. Prevalence of multiple chronic diseases, hypertension, and diabetes were 5.14%, 16.8%, and 3.89%, respectively. Educational attainment, income, salt intake, and BMI were identified as independent risk factors associated with multiple chronic diseases. Educational attainment, income, salt intake were significantly associated with hypertension and age, educational attainment, frequency of alcohol drinking, salt intake were associated with diabetes. Multiple chronic diseases, hypertension, and diabetes were associated with sociodemographic, economic, and health behavioral factors. We should consider these variables in the prevention and management programs and policies for patients with multiple chronic diseases.

• Journal of Digital Convergence
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• v.19 no.4
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• pp.167-176
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• 2021

This study aims to analyze economically active females' factors influencing problematic drinking, by their jobs. It examined the socio-demographic and health-related characteristics and problematic drinking status of economically active females over 19, by using data from the 6th Korea National Health and Nutrition Examination Survey. They were analyzed by using IBM SPSS 25.0 and the complex sampling design. The findings show that the problematic drinking rates of economically active females were varied by their jobs: 19.1% for office job; 24.8% for manufacturing job; 12.3% for service job. The factors influencing problematic drinking were also differed by jobs: subjective heath status for office job; marital status and smoking for service job; marital status for manufacturing job. They suggest that convergent drinking management programs customized to jobs should be developed by considering the characteristics of females' physical and emotional traits and their jobs, to reduce their problematic drinking rates.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.411-434
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• 2022

In deep geological disposal concept for spent nuclear fuel, it is well-known that rock mass at near-field experiences the thermal-hydraulic-mechanical (THM) coupled behavior. The mechanical properties of rock changes during the coupled process, and it is important to consider the changes into the analysis of numerical simulation and in-situ tests for long-term stability evaluation of nuclear waste disposal repository. This report collected the previous studies on indirect coupled behaviors of rock. The effects of water saturation and temperature on some mechanical properties of rock was considered, while the change in hydraulic conductivity of rock due to stress was included in the indirect coupled behavior.