P. C 강선에서 Patenting 열처리에 미치는 인장응력의 영향

이찬규,신평우,홍종휘 고려대학교 공학기술연구소 1982 고려대학교 생산기술연구소 연구보고 Vol.17 No.1

Optimum heat treatment producing P.C. wire is the most important for the further drawing. Drawability depends on the metallic microstructure and mechanical properties. Mechanical properties depend on the amount of pro-eutctoid ferrite and the fineness of pearlite. The amount of ferrite and the fineness of pearlite are dominated by the solid solution treatment and the cooling velocity from the sutenitizing temperature to the patenting temperature. Basides the above, the tension stress is very effective for ausenitizing and eutectoid reaction. The results obtained from this investigation could be summarized as follows. 1. Drawabdity was lowered by the precipitation of pro-eutectoid ferrite as the solid solution treating time was longer. 2. Slow cooling velocity from solid solution treating temperature to the isothermal transformation temperature made the drawability poor. 3. Solid solution treatment under tension stress was very effective for reducing the solid solution treating time and for refining the pearlite. 4. Solid solution treatment under tension stress and rapid cooling from 950 % to 540 % made the pearlite fine and increased drawability.

티타늄 스폰지를 이용한 수소 흡장 특성

이성호,김광락,안도희,유재형,백승우,손종식,임성팔,정홍석 한국공업화학회 2001 응용화학 Vol.5 No.2

Hydrogen absorption experiments were carried out by the titanium(Ti) sponge for investigating the characteristics of hydrogen absorption. From experimental results, Ti sponges showed the high hydrogen absorption capacity inspite of low reaction temperature. The H/M which mean the capacity of hydrogen absorption was measured 2.0 for Ti sponge in the experimental condition of 25℃. The effects of the reaction temperature, activation conditions, and the presence of helium in the hydrogen were investigated.

B 첨가 고탄소강의 흑연화에 미치는 냉간압연의 영향

박영구,우기도,이창희,류재화,나종필 한국열처리공학회 1999 熱處理工學會誌 Vol.12 No.2

The graphitization is affected by the addition of small amount of the elements(such as Si, Al, Ni, B, Cr and Mn etc.) and the pre-treatment(such as cold rolling). Boron is well known element to accelerate the graphitization of cementite in high carbon steels. Also, cold rolling is known to accelerate the graphitization. But the graphitization nucleation mechanism by cold rolling is few reported. Therefore the effect of cold rolling in Fe-0.5%C-1.0%Si-0.47%Mn-0.005%B steel on the graphitization is investigated quantitatively using hardness test, optical microscope and scanning electron microscope, neutron induced microscopic radiography. The nucleation of graphite in cold-rolled Fe-0.5%C-1.0%Si-0.47%Mn-0.005%B steel is formed at void which is formed at pearlite/pearlite boundary by cold rolling. But the effect of cold rolling on graphitization in boron addition steel is more effective than that of no boron addition steel due to segregation of BN at void in boron addition steel.

스퍼터링법으로 제작된 TiO2 박막의 광촉매 특성에 관한 연구

최진호,이원재,김장규,신동훈,장광필,남궁규철 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.9

TiO₂ films deposited on glass were prepared by plasma sputtering method. The dependence of structural properties on the deposition conditions and the photocatalytic degradation of methylene blue were investigated. When the oxygen partial pressure was higher than 5%, as-deposited TiO₂ films exhibited an almost amorphous structure under DC plasma condition. A transition at which metallic mode deposition(Ti) changed to dielectric mode deposition(TiO₂), was observed at the 5∼10% oxygen partial pressure under RF plasma condition. The amorphous structure changed to anatase structure by heat treatment at 400℃ for 4 hours. Crystallized anatase structure had a preferred orientation along 〔101〕 direction. For 150 min of photocatalytic degradation, the concentration of methylene blue was reduced by half.

Mycobacterium Avium - in tracellulare Complex 와 M . Fortuitum 에 의한 폐항산균증(肺抗酸菌症) 3예

김상재,홍수표,배길한,김성진,진병환,정충모 대한미생물학회 1982 大韓微生物學會誌 Vol.17 No.1

Two cases of pulmonary disease in a 54 year-old female and a 70 year-old male patient due to Mycobacterium avium-intracellulare complex (MAIC) and a case of pulmonary infection in a 69 year-old male patient due to M fortuitum (MF) were found recently in this institute. All three patients bad a long history of anti-tuberculous chemotherapy because they were initially diagnosed as pulmonary tuberculosis. A 70 year-old male patient infected with MAIC had an unsuccessful chemotherapy history of isoniazid (INH), para-aminosalicylic acid (PAS) and streptomycin (SM) with an incomplete, temporary, symptomatic improvement, for three years since 1964 when he was first diagnosed as pulmonary tuberculosis on physical examination. A 54 year-old female patient infected with MAIC also had an unsuccessful chemotherapy history with the various anti-tuberculous drugs since 1958. Both patients discharged large number of MAIC in their sputum specimens for at least more than one year, but no M tuberculosis at all. A 69 year-old male patient infected with MF was diagnosed as moderately advanced pulmonary tuberculsis in 1977. Combined chemotherapy with INH+PAS+pyrazinamide (PZA) improved his clinical symptoms, however, his chest radiograph was deteriorated again in 1980 one year after he stopped therapy. Therefore he started chemotherapy again with INH+ethionamide (TH)+cycloserine(CS) but no improvement was noticed. MF was cultured from his sputum in August 1983 and he continuously discharged the same baeilli until last examination of January l982. Whether all three patients were initially infected with nontuberculous mycobacteria or complicated with predisposing tuberculosis was not clear because there were no reliable bacteriological Examination records.

한강수계의 오염현황에 관한 연구

정팔진,민경석,이찬기 고려대학교 공학기술연구소 1976 고려대학교 생산기술연구소 연구보고 Vol.8 No.1

The water quality of the Han river which has been serving as a major water source for 'the Seoul Metropolitan area is discussed in this paper in terms of D0, BOD and others. The water quality upstream of the Jungryang-chun junction to Paldang was favorable during the investigation period: June 6 to July 27, 1977 with a flow range from 175 to 648㎥/sec. However, DO and BOD values were increased toward the downstream from the Jungryang-chun junction. The water quality downstream of the 2nd Han river bridge could not be simply interpreted due to the tidal effect.

Sbi3 를 첨가한 25% Bi2Te3-75% Sb2Te3 와 15% Bi2Te3-85% Sb2Te3 단결정의 전기적특성과 열전특성

현도빈,황종승,심재동,오태성,하헌필 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.8

The temperature dependences of the electrical and thermoelectric properties of the SbI₃-doped 25% Bi₂Te₃-75% Sb₂Te₃ and 15% Bi₂Te₃-85% Sb₂Te₃ single crystals, grown by the Bridgman method, were measured at temperatures ranging from 77 K to 600 K. For the Sb₂Te₃-rich single crystals, the temperature dependence of the Hall mobility was T^(-1.0) regardless the Sb₂Te₃ contents and added amount of SbI₃. The temperature dependences of (m*/m_o)^(3/2)·μ_c and effective mass m*/m_o were T^(-1.5) and T^(-1/3), respectively. The decrease of the saturated hole concentration and the change of the slope of the Seebeck coefficient with temperature were considered in the view point of the two sub-bands in the valence band. The maximum figure-of-merit at 300 K of 0.2 wt% SbI₃-doped 25% Bi₂Te₃-75% Sb₂Te₃ and 0.4 wt% SbI₃-doped 15% Bi₂Te₃-85% Sb₂Te₃ single crystals were 2.25×10^(-3)/K and 1.95×10^(-3)/K, respectively.

자동차 엔진오일 열화상태 in situ 측정용 전기용량 센서

이래덕,김한준,세메노프 한국센서학회 2001 센서학회지 Vol.10 No.4

A coil-type capacitive sensor on which the deterioration of the car engine oil can be in situ measured, has been developed. The sensor was designed to get over 10 pF at the limited space on the drain hole of the oil pan. The design factors for stable capacitance measurement such as coil diameter and winding condition, materials and configuration of the coil former, and shielding method, etc., were known by both computer simulation and experimental investigations. The dielectric properties measured by several sensors for an used sample oil were consisted within 0.25 %. The sensor installed on the cat having severe vibration, temperature and humidity fluctuation, even electromagnetic noise, has shown very distinguishable results.

요통 예방을 위한 요추부하 평가에 관한 연구

양성환,김대성,박범,갈원모,강영식 한국산업안전학회 1998 한국안전학회지 Vol.13 No.4

The objective of this study is to conduct the prevention method using electromyography that is to resist the strain on L5/S1 disc and to measure the heart rate for the prevention of low back pain during lifting. EMG signals and heart rate were analyzed under the condition of fixed vertical factor (20∼80㎝), two horizontal factors (35㎝, 55㎝), and two weight factors (10㎏, 25㎏) 2 times per minute for each lifting task. Eight healthy male workers performed nine-step stretching exercises which were intensified back power at the L5/S1 disc for six months. After completion of the two trials, the results were compared. The results of this analysis show that EMG signals have more an effect on the weight than the horizontal factors similar to those analyzed previous study, and are decreased. Therefore, those exercises presented very efficient. Also, there are not statistically significant differences on the analysis result of heart rate between weight factors.

전자선 조사가 저밀도 폴리에틸렌 필름의 전기 전도도특성에 미치는 영향

홍진웅,이종필,이수원 한국산업안전학회 1999 한국안전학회지 Vol.14 No.2

In this paper, physical properties and electrical conductivity of electron beam irradiated low density polyethylene are studied. The specimens of thickness 100㎛ irradiated as each 1Mrad, 2Mrad, 4Mrad, 8Mrad, 16Mrad and virgin are used in this experiment. FTIR analysis shows strong absorptions by methyl groups in wavenumbers 720㎝^(-1) and 1463㎝^(-1), and did not show any evidences of the presence of residual carbonyl groups. From the DSC analysis, the crystalline melting point of electron beam irradiated specimen is lower than that of virgin specimen. 1Mrad irradiated sample shows the stable electrical conductivity characteristics with both temperature and electric field.