http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
오늘 본 자료
Fe-7%Ni-0.4%C 마르텐사이트합금의 미세조직과 진동감쇠능에 미치는 용체화처리온도의 영향
이영국,지광구,최종술 ( Young Kook Lee,Kwang Koo Jee,Chong Sool Choi ) 한국열처리공학회 1998 熱處理工學會誌 Vol.11 No.1
The objective of this study is to investigate the effect of solution-treatment temperature on the microstructure and damping capacity of a martensitic Fe-7%Ni-0.4%C alloy. The size of lath increased from 0.3㎛ to 0.55㎛ with increasing the solution-treatment temperature from 700 to 1100℃. In addition, the size of block, packet, and austenite grain had tendency to increase with increasing solution-treatment temperature. The damping capacity of the Fe-7%Ni-0.4%C martensitic alloy decreased with increasing the solution treatment temperature. The reason is not attributed to the increase in the size of lath, block, packet, and austenite grain, but to the increase in vacancy concentration which hinders dislocation motion.
다발체형성과 인발공정에 의해 제조된 Cu-Nb 미세복합재료의 미세조직과 전도도
권회준,홍순익,지광구,Kwon, Hoi-Joon,Hong, Sun-Ig,Jee, Kwang-Koo 한국재료학회 2001 한국재료학회지 Vol.11 No.2
다발체형성 제조기술을 이용하여 심하게 인발가공된 Cu-Nb 미세복합재료 전선의 전기적 특성과 열처리에 따른 미세조직 변화와의 관계에 대하여 연구하였다. 다발체형성과 인발공정에 의해 제조된 전선에서 Nb필라멘트 단면방향의 형태는 직선이거나 약간 굽은 형태로 나타났다 Nb필라멘트 형태의 차이는 고온에서의 다발체형성 제조공정중의 Nb필라멘트의 파손과 실린더화에 의해 발생하였다. Cu-Nb 미세복합재료의 비저항은 Cu-Nb 계면에서의 전자 산란에 의해 주로 결정된다. $400^{\circ}C$의 어닐링온도 이하에서 전도도의 감소는 침상형태 석출물의 정합변형율과 관계된 산란의 기여가 증가하기 때문이다. 비저항의 비 ($\rho_{295K}$/$\rho_{75K}$)의 약간의 감소는 또한 Nb원자의 석출 때문이다. 50$0^{\circ}C$의 어닐링온도에서 Cu-Nb 미세복합재료의 전도도 중가는 Nb필라멘트의 조대화와 구형화때문이다 The electrical properties of heavily drawn bundled Cu- Nb filamentary microcomposite wires were examined and correlated with the microstructural changes caused by thermomechanical treatments. The cross sectional shape of Nb filaments in wires fabricated by bundling and drawing appear straight or slightly curved. The different shape of Nb filaments is attributed to the break- up and cylinderization of Nb filaments during the bundling process at high temperatures. The resistivity of Cu-Nb microcomposites is predominantly controlled by electron scattering at Cu-Nb interfaces. The decrease of the conductivity below the annealing temperature of $400^{\circ}C$ is due to the increasing contribution of the scattering associated with coherency strains of needle- shaped precipitates. The slight decrease of the resistivity ratio (${\rho}_{295K}/{\rho}_{75K}$) is also due to the precipitation of Nb atoms. The increase in conductivity in Cu-Nb microcomposites at an annealing temperature of 50$0^{\circ}C$ is due to the coarsening and spheroidization of Nb filaments.
탄소나노섬유 표면 구리 무전해 도금에 미치는 분산제와 도금 전처리의 영향
한준현,석현광,이상수,지광구,Han, Jun-Hyun,Seok, Hyun-Kwang,Lee, Sang-Soo,Jee, Kwang-Koo 한국분말야금학회 2009 한국분말재료학회지 (KPMI) Vol.16 No.2
This paper deals with the effects of the surfactant and preplate process (sensitization and activation) on electroless copper plating on carbon nano-fiber (CNF). Ultrasonic irradiation was applied both during dispersion of CNF and during electroless plating containing preplate process. The dispersion of CNF and flatness of the plated copper film were discussed based on the changes in surfactant concentration and preplate process time. It was clearly shown that high concentration of surfactant and long time of preplate process could promote the agglomeration of CNF and uneven copper plating on CNF.
스퍼터링 중 외부자기장이 자성박막의 자기적 특성에 미치는 영향
안현태 ( Hyun Tae Ahn ),임상호 ( Sang Ho Lim ),지광구 ( Kwang Koo Jee ),한준현 ( Jun Hyun Han ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.6
A magnetic device which enables the application of a strong and uniform magnetic field to thin film during sputtering was designed for controlling the magnetic anisotropy using a three dimensional finite element method, and the effects of the external magnetic field on the magnetic properties of sputtered thin films were investigated. Both the intensity and the uniformity of the magnetic flux density in the sputter zone (50 mm ×50 mm) was dependent on not only the shape and size of the magnet device but also the magnitude of stray fields from the magnet. For the magnet device in which the distance between two magnets or two pure iron bars was 80-90 mm, the magnetic flux density along the direction normal to the external magnetic field direction was minimum. The two row magnets increased the magnetic flux density and uniformity along the external magnetic field direction. An Fe thin film sputtered using the optimized magnet device showed a higher remanence ratio than that fabricated under no external magnetic field.
냉간 단조된 5083 알루미늄 합금에서의 집합조직 발달과 소성변형 비
한준현,지광구,오규환 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.6
5083 aluminum alloys were cold-forged to study the possibility of enhancing the formability and reducing the planar anisotropy. Texture evolution during cold forging was discussed with pole figure and orientation distribution function (ODF). The formability and planar anisotropy in forged 5083 aluminum alloys were evaluated in terms of the r-value (plastic strain ratio or Lankford parameter) which was not only calculated from the measured pole figures but also measured in direct by tensile tests. The (110) <uvw> fiber texture was developed during cold forging, by which the 5083 aluminum alloy having high formability and low planar anisotropy could be produced. (Received March 18, 2004)
Fe-17%Mn-X%C 마르텐사이트 합금의 진동감쇠능에 미치는 시효의 영향
최종술,지광구,백승한,오영선 대한금속재료학회(대한금속학회) 1996 대한금속·재료학회지 Vol.34 No.5
Variation of damping capacity with aging time in an Fe-17%Mn alloy with different carbon contents has been studied from the kinetic viewpoint. The average of decreasing velocity of damping capacity at each aging temperature increases with increasing carbon content and reaches maximum around 0.12wt%C, and then decreases with further carbon content. This indicates that the decreasing velocity of damping capacity can be represented by an equation V_d= K·A_d·C_s, where K is constant, .A_d the total interfacial area of damping sources per unit volume, and C_s the amount of carbon segregated at damping sources. The activation energy for the damping decrease process is 6 ㎉/㏖ regardless of the carbon content. Such a small activation energy suggests that carbon segregation at damping sources is caused by interaction of carbon atoms with damping sources without long range diffusion of carbon atoms through lattices.
Ni-Ti 형상기억합금의 상변능에 미치는 외부응력의 영향
홍종휘,성윤막,지광구,갑명철 대한금속재료학회(대한금속학회) 1988 대한금속·재료학회지 Vol.26 No.8
The effect of external stress on the phase transformation behavior of annealed and aged Ni-Ti alloys has been studied by the tensile test and the measurement of electrical resistance. Martensitic (M_s) and austenitic transformation starting temperatures (A_s) increased gradually with increasing stess up to 129 MPa and increased rapidly at a rate of 0.2℃/MPa above this stress level. However, incommensurate (T'_R) and commensurate phase transformation starting temperatures (T_R) increased very slowly at a rate of 0.06℃/MPa with the increasing stress. Martensitic transformation temperature range, ΔT(M_s∼M_f), and the stress at which ΔT was kept constant were larger for the aged specimen than for the annealed specimen. The stress at which the strain accompanied by incommensurate and commensurate phase transformation began to decrease (ε-1c) was higher for the annealed specimen than for the aged specimen. these facts imply that the incommensurate and commensurate phases are more stable in the annealed specimen than in the aged specimen. While the residual stress (ε_p) in the annealed specimen remained low regardless of the stress level, ε_p in the aged specimen began to increase rapidly at 240 MPa. This means that slip deformation is more difficult for the annealed specimen than for the aged specimen.
Fe-Mn-Si 합금에서 집합조직 형성과 이에 따른 형상기억효과의 이방성
신명철,최종술,지광구,송준오,장우양 대한금속재료학회(대한금속학회) 2001 대한금속·재료학회지 Vol.39 No.2
This study is aimed at investigating the anisotropy of shape memory effect in Fe-based alloy. An Fe-15Mn-3Si-4Co-5Cr alloy was cold rolled by 92%, and annealed at 630℃ for 46 min. The alloy undergoes γ→ε→α’ transformation by cold rolling and γ is restored with a major preferred orientation of (110)γ[001]γ by the annealing. The specimens for shape memory effect and tensile test were taken 0, 45, 70, 80 and 90 degs to the rolling direction. The specimen taken along 70 degs to the rolling direction exhibits the best shape memory effect. An analysis of the (110)γ[001]γ texture reveals that the specimen experiences the deformation along [221]γ which is the most expandable direction in the γ→ε transformation. In tensile test, the best SME specimen shows the lowest yield stress, indicating that the transformation take place most easily since the deformation is applied to the preferential direction to the deformation.