국산 활엽수의 물리적성질과 기계적성질

千光鉉,琴彩,張忠根 충남대학교 자연과학연구소 1978 學術硏究誌 Vol.5 No.2

The present paper is concerned with the physical and mechanical properties of the broad-leaved trees grown in Korea. The sample trees were selected 5 species (Zelkowa serrata thunberg, Prunus serrulata ver spondanea, Castanea, crenata siebold and zucarini, Siebold & Zuccarini, Maackia amurensis.) grown in Eunsan-Myen Buyer-Gun Choon-Chyung-Nam Do, Korea. We have investigated sapwood width, specific gravity, shringkage, compression strength, shear strength, Tensile strength and hardness of them.

Fe-N 强磁性 薄膜의 磁氣-光效果

千光鉉 충남대학교 자연과학연구소 1976 學術硏究誌 Vol.3 No.1

The magnetic and magneto-optic properties of ferromagnetic Fe-N films deposited in nitrogen atmosphere under various pressures ranging from 2 x 10^(-5)Torr. to 9×10^(-3)Torr have been investigated. The magnetic properties of these films were measured with a Homling type hysteresis loop tracer. The magneto-optic Kerr effect of these films were investigated by measuring the rotation angle of polarization of the reflected light from surfaces of these films using an ellipsometer. The saturation magnetization, Ms, of films deposited at pressures between 2×10^(-5), and 5×10^(-4) Torr showed a tendency to increase with increasing pressure and reach a maximum value (M_(s)=2050 gauss), followed by a decrease with further increase of pressure. Electron diffraction patterns of the films deposited at pressures near 5×10^(-4)Torr indicated clearly the presence of Fe_(16)N_(2). The Kerr rotation angles are found to he proportional to the saturation magnetization of the Fe-N films. The maximum value of the Kerr rotation angle, θ_(K)=2.5×10^(-3) rad, was obtained in the Fe_(16)N_(2).

국산유용목재의 물리적 및 기계적 성상에 관한 연구

千光鉉,琴彩,張忠根 충남대학교 자연과학연구소 1978 學術硏究誌 Vol.5 No.1

The present paper is concerned with the physical and mechanical properties of the useful woods grown in Korea. The sample trees were selected 8 species(Quercus Serrata, Quercus variabiblis, Quercus dentata, Quercus acutissima, Carpinus erosa, Styray japonica, Acer formosum Carriere var coreanum, Cornus controversa) grown in Eunsan-Myon Buyer-Gun Choong Chyung-mam-do, Korea. We have investigated sapwood width, specific gravity, shringkage, compression strength, stress and strain, partial compression strength, Banding strength, shear srrength, Tensile strength, Absorbed energy and hardness of them.

Bi-Sn 薄膜의 熱電特性에 關한 硏究

千光鉉,琴彩,金基元 충남대학교 자연과학연구소 1979 學術硏究誌 Vol.6 No.2

Bi:Bi-Sn and Sb:Bi-Sn thin film thermocouples(TFTC) have been prepared by vacuum deposition method, with thickness of the films ranging 3500Å-5700Å. The Bi-SnTFTC with 15%-20% of Sn content produced the largest thermal electromotive farce and showed good thermoelectric properties.

强磁性 Fe-Ni 薄膜의 縱 Kerr 效果에 關한 硏究

千光鉉 충남대학교 자연과학연구소 1975 學術硏究誌 Vol.2 No.2

The magnetic properties and dependence of the magneto-optic effects upon the composition of the ferro-magnetic Fe-Ni alloy films have be-n investigated. The Fe_(1-X)Ni_(X) (0≤x≤1) films of the thickness 2000A were deposited on the glass substrates kept at roam temperature under 2×10 exp (-6) Torr. The magnetic properties of these films were measured with a hysteresis loop tracer. The saturation magnetization, Ms, and coercive force, Hc, are found to be varied with the chemical composition, and the maximum value of Ms, 1789 gauss, is obtained with 10%Ni-Fe films and the minimum value of Hc, 20 Oe is obtained with 80%Ni-Fe films. It is also found that the films have the easy direction of the magnetization in the films plane by measuring the variation of the hysteresis loop as a function of angle between the film direction of the magnetic field and the film plane. Therefore, the magneto-optic effects of these films were investigated for longitudinal Kerr effects. The Kerr rotation angles and the ellipticities in terms of the weight ratios of Ni in Fe were obtained with the ellipsometric method. The Kerr rotation angles, θ_(K), are found to be varied with incident angles of light, and the maximum value of θ_(K) is obtained with 60° in Fe_(1-X) Ni_(X)(0≤x≤0. 5) films, while it is obtained with 50° in the case of larger than 60%Ni composition. The Kerr ellipticities, ε_(K), are found to be varied with incident angles of light, and the maximum value of ε_(K) is obtained with 65. That does not affect above characteristics. The Kerr rotation angles, θ_(K), and the ellipsities, ε_(K) are found to be varied with the Fe-Ni composition, and the maximum value of θ_(K) 14.2×10 exp (-4) rad, and of ε_(K) 15.5×10 exp (-1) are obtained with 10% Ni-Fe films. The crystal structure of these films was confirmed by electron diffraction. The crystal structure of Fe_(1-X)Ni_(X) (O≤x<0.3) films has the bcc and of Fe_(1-X)Ni_(X)(0.4<x≤1) films has the fcc. The Kerr rotation angles and the Kerr ellipticities are found to be proportional to the saturation magnetization of the Fe-Ni films. The value of θ_(K)/M_(S) is determined to be 7.7×10 exp (-7) and 5.0×10exp (-7) in the bcc and fcc structure, respectively. The value of ε_(K)/M_(S) is determined 8.7×10 exp (-7) and 12.5×10 exp (-7) in the bcc and fcc structure, respectively.

Ultra High Saturation Magnetization of Iron Films Deposited in a Nitrogen Atmosphere

Kim, Taik Kee,Chun, Kwang Hyun 충남대학교 자연과학연구소 1980 學術硏究誌 Vol.7 No.1

2×10^(-5) Torr.부터 7×10^(-3) Torr까지 범위의 질소 분위기에서 증착한 Fe막의 포화자화가 증착시 질소 분압에 미치는 영향을 계통적으로 조사하였다. 포화자화의 온도 의존성 및 결정구조의 해석 결과 포화자화가 2200±100 Gauss를 갖는 Fe_(16)N_(2)인 새로운 자성 재료를 발견 하였다. Fe_(16)N_(2)의 Mossbauer효과 실험 결과와 종합하여 Fe의 평균 자기 모멘트의 값은 약 2.9μB 임을 알았다.

질화철의 염산용액에 의한 용출

金演斗,李弘,千光鉉 충남대학교 자연과학연구소 1978 學術硏究誌 Vol.5 No.2

Degrees of acid attack to low carbon steels and nitrited steels have been measured in hydrochloric acid solutions. The former shows higher resistance compared to the latter in same experimental conditions.

炭素鋼中의 크롬擴散과 空孔機構

張忠根,金基元,千光鉉 충남대학교 자연과학연구소 1974 學術硏究誌 Vol.1 No.1

Chromium diffusion into the carburized iron is measured over the temperature range 800℃-1. 200℃. The diffusion coefficient is obtained by the calculation from the diffused time and depth. Chromium diffusion into the carburized iron appears notably over the temperature 900℃, and the diffusion coefficient of chromium decreases with an increase of the cardon concentration ironin. The above experimental results have shown that a major penetration mechanism is jumping into the vacancy which has been made in the transition from BCC iron structure to FCC type. The relationships of the depth of penetration and diffusion coefficient with the Carbon concentration under the constant temperature is given by the equation X_(p)=50(1-0.96C). D=0. 028X_(p)^(2)

크롬도금시 음극시료의 회전효과에 관한 연구 (1)

장충근,권혁무,천광현 대한금속재료학회(대한금속학회) 1974 대한금속·재료학회지 Vol.12 No.3

Sargent 浴內에서 陰極試料의 回轉이 偏心, 硬度 및 析出量에 미치는 效果를 檢討하여 다음과 같은 結果를 얻었다. (l) 陰極試料의 回轉에 依해서 偏心은 鍍金된 두께의 5%以下까지 減少되었다. (2) 回轉線速度가 20×10^(-4) m/ses인 경우에는 析出量과 表面組織의 均一性이 增加되었다. (3) 回轉線速度가 20×10^(-4) m/sec 以上인 경우에는 析出量이 減少되고 陰極表面에 밀림무늬가 나타났다. The effect of Rotation of cathode on eccentricity, hardness and deposited quantities were investigated by rotating of cathode sample in the Sargent bath. And following results are obtained ; (1) The eccentricities were decreased below 5% of the deposited thickness by rotating of cathode. (2) The deposited quantities and uniformity of surface structure were increased at the linear velocity of 20×10^(-4) m/sec. (3) The deposited quantities were decreased when the linear velocity is elevated more than 20×10^(-4) m/sec and the pushed pattern was appeared on the cathode surface.

크롬도금시 음극시료의 회전효과에 관한 연구

권혁무,장충근,천광현 대한금속재료학회(대한금속학회) 1974 대한금속·재료학회지 Vol.12 No.1

1. 서론 크롬鍍金은 各種耐磨耗性 機械部品 加工의 最終工程으로서 매우 重要한 位置를 차지하고 있으며 最近에는 크롬鍍金을 必要로하는 精密部品의 加工程度가 向上됨에 따라 高度의 鍍金技術과 精密度가 要求되고 있어 이 分野에 對한 硏究가 절실히 要求되고 있다. 特히 습동면의 耐磨耗性을 目的으로 크롬鍍金을 두껍게 시행하는 圓筒形의 精密機械 部品들이 鍍金過程에서 偏心 또는 不均一하게 被覆되었을 경우 鍍金終了후 다시 機械的인 加工 및 硏磨工程을 必要로하는 경우가 있음으로 이 폐단을 除去키 위한 方法을 모색하는 한편 析出金屬粒子를 보다 微細化시키고 吸藏 gas量等을 減少시켜 耐磨耗性과 硬度를 向上시키기 위하여 被鍍金試料를 回轉시키면서 鍍金한후 그 效果를 檢討하고 이 結果를 다시 초음파를 조사하면서 鍍金한 試料와 比較해 보았다. 2. 실험방법 10 ㎜ø×74 ㎜의 鋼管을 鍍金試料로 使用하였고 半徑 25 ㎜의 圓周上에 8% Sb-Pb 合金棒 2∼6個를 放射狀으로 設置하여 陽極으로 사용하였다. 鍍金液은 CrO₃ 250g/l에 H₂SO₄ 2.5g/l를 첨가한 후 ℓ當 4A/d㎡의 低電流로 約 30분간 弱電解하여 3價크롬의 量을 2g/l로 조절한 후 每鍍金時마다 일정량씩 채취하여 1회 사용한 후 폐기하였다. 回轉裝置는 A. C. 直捲 motor의 入力電壓을 variac으로 降下시켜 回轉速度를 조절한 후 다시 감속 gear set로 감속시켜 試料를 5, 15, 45 rpm. 으로 각각 회전시키면서 60분간 鍍金하였다. 鍍金液의 溫渡는 temp. controller와 solenoid valve를 사용하여 50±2℃로 유지하였고 초음파 도금시료를 얻기 위하여 電解槽의 下部에 兀型 ferrite transducer의 輻射面을 가볍게 接觸시켜 垂直上方向으로 28, 50, 100 KHz의 초음파를 각각 조사하면서 sampling하였고 偏心效果를 檢討하기 爲하여 위와같은 條件下에서 4:4, 4:3, 4:2로 偏心되게 陰極을 設置하여 鍍金하였다. 3. 실험결과 이상과 같은 방법으로 얻어진 시료들에 對하여 (a) 偏心率 (b) 析出量 (c) 硬度 (d) 表面組織 等을 比較檢討하였으며 시료의 偏心率은 回轉 鍍金方法에 의하여 개선되었고 析出金屬의 硬度와 表面組織은 초음파 도금시가 양호하였다.