시험평가의 신뢰도 증진을 위한 방안에 관한 연구

김형원,박상은 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.4

수지 노화와 잔류응력 변화가 Avimid? K3B/IM7 복합재 적층에 미치는 영향

김형원 한국군사과학기술학회 2005 한국군사과학기술학회지 Vol.8 No.3

In this paper, the effects of matrix hygrothermal aging and residual stress changes on Avimid?? K3B/IM7 laminates in 80℃ water were studied. The factors causing the 80℃ water to degradation of the laminates could be the degradation of the matrix toughness, the change in residual stresses. After 500 hours fully saturated aging of the neat resin, the weight gain was 1.55% increase with the diffusion coefficient 7×10-6m2/sand the fracture toughness was decreased about 41%. After 100 hours fully saturated aging of the [+45/0/-45/90]s K3B/IM7 laminates in 80℃ water, the weight gain was 0.41% increase with the diffusion coefficient 1×10-6m/s2 and the loss of the microcracking fracture toughness was 43.8% of the original toughness. To see whether the residual stress influenced the fracture toughtnes, two ply [90°/0°] laminates were put in 80℃ water from 2 hours to 8 hours. The changes in residual stress in 8 hours are less than 3MPa. Because the 3MPa change is not sufficient to degrade the laminates, the main factor to degrade the microcracking fracture toughness was the of the matrix fracture toughness.

Avimid?? K3B/IM7 복합재료의 80°C 물에서의 노화현상

김형원 한국추진공학회 2005 한국추진공학회지 Vol.9 No.4

The Hygrothermal aging of the laminates of Avimid K3B/IM7 in 80°C water was studied as a function of immersion time prior to forming microcracks. The factors causing the 80°C water to degradation of the laminates could be the degradation of the matrix toughness, the change in residual stresses or the interfacial damage between the fiber and the matrix. The times to saturation in 80°C water for the laminates and for the neat resin were 100 hours and 500 hours. After 500 hours aging of the neat resin, the glass transition temperature was changed less than 1% by DSC test, and the weight gain was 1.55% increase with the diffusion coefficient 7x10-6 m/s2 and the fracture toughness was decreased about 41%. After 100 hours fully saturated aging of the [+45/0/-45/90]s K3B/IM7 laminates in 80°C water, the weight gain was 0.41% increase with the diffusion coefficient 1x10-6 m/s2. In 100 hours, the loss of the fracture toughness of the laminates was 43.8% of the original toughness by the microcracking fracture toughness criterion. Therefore, the main factor to degrade the microcracking toughness of the laminates could be the degradation of the matrix fracture toughness. 미세균열이 생기기 전 80°C 물속에서 침수시간에 따른 Avimid K3B/IM7 복합재의 습기노화 현상에 관하여 연구하였다. 80°C 물속에서 복합재의 파괴인성을 저하시키는 요인으로는 수지 파괴인성의 저하나 잔류응력의 변화 그리고 섬유와 수지 사이의 계면 손상이다. 80°C 물속에서 수지에 습기가 포화되는 시간은 500 시간이며 K3B/IM7 복합재에 습기가 포화되는 시간은 100 시간이다. 수지가 500 시간 가속노화한 후 DSC 시험을 한 결과 Tg는 1% 이내 증가하였으며, 무게는 7x10-6 m/s2 확산속도로 1.55% 증가하였다. K3B/IM7복합재에 관하여 물속에서 100시간 지난 후 무게는 1x10-6 m/s2 확산속도로 0.41% 증가했다. 500 시간 노화한 후 수지의 파괴인성은 41% 저하하였으며 100 시간 노화한 후 [+45/0/-45/90]s K3B/IM7 복합재의 미세균열 파괴인성은 43.8% 감소하였다. 그러므로 80°C 수분노화 시험에서 복합재 적층의 파괴인성을 감소시키는 주요 원인은 수지 파괴인성의 저하라고 할 수 있다.

온실가스 CO₂의 수소화에 의한 개미산생산 기술동향

김형원,Kim, Hyeong-Won 한국플랜트학회 2018 플랜트 저널 Vol.14 No.4

一部 工業團地 産業場의 騷音環境과 騷音性難聽에 關한 調査硏究

金炯遠,車喆煥 고려대학교 의과대학 1977 고려대 의대 잡지 Vol.14 No.1

To define status and causes of hearing loss or impairment of workers served in noise environment, and to grope for appropriate methods of prevention, analysing environmental noise from industries concerned and degree of hearing loss of workers by their personal characteristics, 1,603 workers of 7 kinds of industries from which of more than 90 ㏈ had been produced were checked and the noise itself was analyzed by octave band analyzer (SA-52 type). In this 1975 study, giving some emphasis to the noise environment in relation to hearing loss of workers in noise environment of some Korean industries, the results were summarized as follows; 1) Analysing the results of audiogram for 1,603 workers in noise environment, a total of 237 workers (14.8%) was revealed to have hearing loss responsible to continuous exposure to noise environment showing, in detail, 16.6% of coal mining, 16.3% of textile, and 15.1% of metal workers by industry. And as for duration of service year, the longer the period, the more the occurrence was reaffirmed showing 14.5% of less than 5 years, 15.6% of 5-10 years, 44.4% of more than 10 years of service. Of the above audiogram analysis, the degree of hearing loss by decibel(㏈) also paralleled to duration of service year showing 16.2±2.1㏈ (left) and 14.2±1.4㏈ (right) of less than 5 years service history, and 26±4.3㏈(left) and 28±6.2㏈(right) of 10 years and more. Additionally, E.L.I (Early Loss Index) scale was applied to classify the above cases into 5 grades of hearing loss from A to E? more than 50% Of the above belonged to grade E which meant typical occupational hearing loss. 2) Concerning degree of sound level by industry, the highest value of 95㏈ by A character was shown in coal mining in general and 110㏈ from tunneling department of the above industry in detail. 3) The pattern of hearing loss of workers in general revealed typical tone gape curve at 4,000 ㎐ in audiogram. By industry and degree of hearing loss in detail, the workers in coal mining and textile industries showed remarkable hearing loss. 4) By octave band analyze, most of environmental noise revealed the highest sound pressure level at over medium frequency range.

Friedel-craft의 炭化水素 合成과 合成化學에 加水分解

金鎣元 단국대학 1960 檀苑 Vol.3 No.1

非線形斷面圖의 上工量策政에 關한 硏究

金日道,金亨源 慶一大學校 1992 論文集 Vol.8 No.1

In this paper, using a nonlinear ground profile soil pit volume was calculated with simpon's integral formula. Number of interval was three sistuations that these are second and three degree polynomial of nonlinear geound profile. Calaulated results with this proposition are more accurate than conventional estimation methode of soil pit volume since these formulas generally approximate the ground profile better than the linear profile formula. The volume of the linear profile is different that of the nonlinear profile formulas. This nonlinear ground profile formulas are relativity simple opposite to conventional estimation methode and amenable to computations by calaulators. Further research should be made in more complex ground prifile.

The effects of matrix aging and residual stress changes on $Avimid^{(R)}$ K3B/IM7 laminates

김형원,Kim, Hyung-Won The Korea Institute of Military Science and Techno 2005 한국군사과학기술학회지 Vol.8 No.3

In this paper, the effects of matrix hygrothermal aging and residual stress changes on $Avimid^{(R)}$ K3B/IM7 laminates in $80^{\circ}C$ water were studied. The factors causing the $80^{\circ}C$ water to degradation of the laminates could be the degradation of the matrix toughness, the change in residual stresses. After 500 hours fully saturated aging of the neat resin, the weight gain was 1.55% increase with the diffusion coefficient $7{\times}10^{-6}m^2/s$ and the fracture toughness was decreased about 41%. After 100 hours fully saturated aging of the $[+45/0/-45/90]_s$ K3B/IM7 laminates in $80^{\circ}C$ water, the weight gain was 0.41% increase with the diffusion coefficient $1{\times}10^{-6}m^2/s$ and the loss of the microcracking fracture toughness was 43.8% of the original toughness. To see whether the residual stress influenced the fracture toughness, two ply $[90^{\circ}/0^{\circ}]$ laminates were put in $80^{\circ}C$ water from 2 hours to 8 hours. The changes in residual stress in 8 hours are less than 3MPa. Because the 3MPa change is not sufficient to degrade the laminates, the main factor to degrade the microcracking fracture toughness was the degradation of the matrix fracture toughness.

제 23 차 학술대회 : 56. 종말회장 천공성 복막염과 Salmonellosis 에 대한 임상적고찰

김형원,이경찬,김세민 대한외과학회 1971 대한외과학회 학술대회자료집 Vol.- No.-

The Aging Effect of $Avimid^(R)$ K3B/1M7 Laminates in $80^{\circ}C$ Water

김형원,Kim Hyung-Won 한국추진공학회 2005 한국추진공학회지 Vol.9 No.4

미세균열이 생기기 전 $80^{\circ}C$ 물속에서 침수시간에 따른 $Avimid^(R)$ K3B/IM7 복합재의 습기노화 현상에 관하여 연구하였다. $80^{\circ}C$ 물속에서 복합재의 파괴인성을 저하시키는 요인으로는 수지 파괴인성의 저하나 잔류응력의 변화 그리고 섬유와 수지 사이의 계면 손상이다. $80^{\circ}C$ 물속에서 수지에 습기가 포화되는 시간은 500 시간이며 K3B/IM7복합재에 습기가 포화되는 시간은 100 시간이다. 수지가 500 시간 가속노화한 후 DSC 시험을 한 결과 $T_g$는 1% 이내 증가하였으며, 무게는 $7\times10^{-6}m/s^2$ 확산속도로 1.55% 증가하였다. K3B/IM7복합재에 관하여 물속에서 100시간 지난 후 무게는 $1\times10^{-6}m/s^2$ 확산속도로 0.41% 증가했다. 500 시간 노화한 후 수지의 파괴인성은 41% 저하하였으며 100 시간 노화한 후 ${[+45/0/-45/90]}_s$ K3B/IM7 복합재의 미세균열 파괴인성은 43.8% 감소하였다. 그러므로 $80^{\circ}C$ 수분노화 시험에서 복합재 적층의 파괴인성을 감소시키는 주요 원인은 수지 파괴인성의 저하라고 할 수 있다. The Hygrothermal aging of the laminates of $Avimid^(R)$ K3B/IM7 in $80^{\circ}C$ water was studied as a function of immersion time prior to forming microcracks. The factors causing the $80^{\circ}C$ water to degradation of the laminates could be the degradation of the matrix toughness, the change in residual stresses or the interfacial damage between the fiber and the matrix. The times to saturation in $80^{\circ}C$ water for the laminates and for the neat resin were 100 hours and 500 hours. After 500 hours aging of the neat resin, the glass transition temperature was changed less than 1% by DSC test, and the weight gain was 1.55% increase with the diffusion coefficient $7\times10^{-6}m/s^2$ and the fracture toughness was decreased about 41%. After 100 hours fully saturated aging of the ${[+45/0/-45/90]}_s$ K3B/IM7 laminates in $80^{\circ}C$ water, the weight gain was 0.41% increase with the diffusion coefficient $1\times10^{-6}m/s^2$. In 100 hours, the loss of the fracture toughness of the laminates was 43.8% of the original toughness by the microcracking fracture toughness criterion. Therefore, the main factor to degrade the microcracking toughness of the laminates could be the degradation of the matrix fracture toughness.