• Journal of Magnetics
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• 제17권2호
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• pp.86-95
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• 2012

This study investigated the effects of adding a third alloying element, Ni, to create $Fe_{70-x}Pd_{30}Ni_x$ (x = 2, 4, 6, 8 at.% Ni) ferromagnetic shape memory alloys (FSMAs). The Ni replaced a portion of the Fe. The $Fe_{70-x}Pd_{30}Ni_x$ alloys were homogenized through hot and cold forging to gain a ~38% reduction in thickness, next they were solution-treated (ST) with annealing recrystallization at $1100^{\circ}C$ for 8 h and quenched in ice brine, and then aged at $500^{\circ}C$ for 100 h. Investigation of the microstructures and magnetostriction indicated that the greater Ni amount in the $Fe_{70-x}Pd_{30}Ni_x$ alloys reduced saturation magnetostriction at room temperature (RT). It was also observed that it was more difficult to generate annealed recrystallization. However, with greater Ni addition into the $Fe_{70-x}Pd_{30}Ni_x$ (x = 6, 8 at.% Ni) alloys, the $L1_0+L1_m$ twin phase decomposition into stoichiometric $L1_0+L1_m+{\alpha}_{bct}$ structures was suppressed after the $500^{\circ}C$/100 h aging treatment. The result was that the $Fe_{70-x}Pd_{30}Ni_x$ (x = 6, 8 at.% Ni) alloys maintained a high magnetostriction and magnetostrictive susceptibility (${\Delta}{\lambda}{_\parallel}{^s}/{\Delta}H$) after the alloys were aged at $500^{\circ}C$ for 100 h. This magnetic property of the $Fe_{70-x}Pd_{30}Ni_x$ (x = 6, 8 at.% Ni) alloys make it suitable for application in a high temperature (T > $500^{\circ}C$) and high frequency environments.

• 한국잠사곤충학회지
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• 제36권1호
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• pp.8-25
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• 1994

본 시험은 누에 일대잡종육종에 있어 양질다사량 우량품종을 육성하기 위한 유전적 정보를 얻고자 수행되었다. 공급재료는 특성이 각각 다른 일, 중, 구 3개지역 6개 품종을 정역으로 이면교잡시켜 F1, F2 각각 30조합으로서 실용형질에 대한 육종가를 얻기 위해 교배조합별 잡종강세 및 조합능력의 검정한 결과는 다음과 같았다. 1. 형질들의 잡종강세는 사질형질인 견사량, 견사장에서 각각 24.51% 및 23.43%로 높았고, 견질형질인 전사종 및 사층중은 15.56%~15.71%, 17.14%~19.01%로서 유의한 강세를 보였으나 유충경과일수 등(5령 및 전령)에서는 부의 잡종강세를 나타내어 그 이용이 유의하였다. 2. 교배조합간의 잡종강세는 5령경과일수의 경우 C70 X Romogua, N9 X Romogua 조합이 높은 부의 강세현상을 보여 사육일수가 단축되는 방향으로, 전견중은 N9 X Romogua, N9 X Romogua 조합이 높은 강세현상을 보여 사육일수가 단축되는 방향으로, 전견중은 N9 X Sansurian의 암, Romogua X Sansurian의 수, 견층중은 암수에 관계없이, N9 X Sansurian의 견사장과 견사량에서는 Sansurian X Romogua의 정역간 교잡에서 각각 높았다. 3. 잡종강세의 모본효과는 N9 X C5, N63 X C70이 전견중과 견층중에서, 견사장에서는 Sansurian이 N63, C5 및 C70과 교잡될 때, 또한 견사량에서는 N9 X C70, N63 X C70이 각각 큰 경향이었다. 4. F1의 조합능력에서 분사량은 GCA, SCA 및 RCA의 전형질에서 유의하여 F1의 조합능력은 상가적 효과와 비상가적 효과가 함께 작용하였으나 형질에 따른 정역간 차이도 컸었다. 5. GCA의 효과는 경과일수에서는 Sansurian이 N9, C5가 견질형질(견장, 견폭, 전견중, 전층중 및 견층비율)과 사질형질(견사장, 견자량 및 생사량비율)에서 세대에 관계없이 높은 정의 효과를 나타내었다. 6. F1의 SCA효과에서 5령경과일수는 Sansurian X C70, romogua X C70, Sansurian X C5, Romogua X C5 등 구주종계와 중국종계간의 교잡에서 전견중과 견층중은 N9 X C5, C70 X Sansurian 이 암수에 관계없이, 또한 Rogmogua X Sansurian, N9 X C5가 F1, F2 간에, 견사량은 Romogua X N63 조합에서, 생사량비율은 Sansurian X Romogua 조합에서 각각 높게 평가되었다.

• 한국가스학회지
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• 제16권3호
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• pp.54-64
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• 2012

실 배관을 평가하는 DWTT (Drop Weight Tearing Test)의 파괴인성 값은 실 배관의 파괴인성 값 및 연성취성천이 온도를 예측할 수 있는 실험방법이므로, 최근 DWTT의 값에 대한 중요성이 증가되고 있다. 본 연구에서는 API X70과 API X65 라인파이프강의 DWTT 후의 온도에 따른 연성파면율, 역파면율, 흡수에너지와 온도 $-60^{\circ}C$~상온)와의 관계를 비교분석 하고자 하였다. X65과 X70의 값에서 마찬가지로 연성파면율 및 흡수에너지는 온도가 낮아질수록 함께 낮아지는 경향을 보였으며, X70의 경우에는 $-40^{\circ}C$ 까지 연성파괴를 보이는 반면, X65는 $-30^{\circ}C$ 까지 연성파괴를 보였다.

• 한국안광학회지
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• 제13권2호
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• pp.17-22
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• 2008

목적: X선용 545 nm 형광판을 위한 결상광학계 개발. 방법: 캐논(Canon)사 CX2-70 모델을 참조하여 설계 기준을 정한 다음 Sigma 2000 광학 설계 프로그램으로 X선용 545 nm 형광판을 위한 결상광학계를 설계 제작하였다. 결과: 새로 설계 제작되어진 X선용 545 nm 형광판 결상광학계의 배율은 -0.225배이고, 이미지 크기는 90 mm${\times}$90 mm이며, 분해선폭은 30% MTF 값 기준으로 0.033 mm인 특성을 보여준다. 이는 캐논 CX2-70 모델보다 큰 화면으로 판독을 할 수 있고, 판독의 분해능도 우수함을 의미한다. 또한 이미지 측 NA값이 -0.196으로 캐논 CX2-70 모 델 -0.139보다 약$\sqrt{2}$배 크게 하였고, 물체 측 NA값도 0.044로 캐논 CX2-70 모델 0.022보다 약 2배 크게 하였다. 이는 필름의 감도를 4배 증가 시킬 수 있는 것을 의미하며 X선의 피폭시간을 1/4로 줄일 수 있음을 뜻한다. 결론: 이미지 크기가 90 mm${\times}$90 mm이고, 15 lines/mm에서 MTF 30% 이상인 특성을 가지며, 캐논 CX2-70 모델에 비해 X선 피폭시간을 1/4로 줄일 수 있는 새로운 X선용 545 nm 형광판 결상광학계를 설계 제작하였다.

• 한국수소및신에너지학회논문집
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• 제31권3호
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• pp.284-292
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• 2020

In this study, hydrogen charging was conducted for API X70 steel by the electro-chemical hydrogen charging method. Right after hydrogen was diffused from the specimen surface to the inside of the X70, the small punch tests and hydrogen concentration analysis was conducted within 5 minutes. Hydrogen was analyzed by melting the whole specimen and detect the gas after melting. Mechanical properties were measured by the small punch (SP) testing. Fracture surface and specimen surface were observed using scanning electron microscope. Three tests were repeated for study sensitivity of the SP test results under a same charging condition. It was observed that the variation of the maximum load, SP displacement at failure, hydrogen concentration as the charging period was not much in the case of X70 as the other steel such as Inconel. It can be argued that X70 base metal may have high hydrogen damage resistance and hydrogen diffusion in the base metal would not cause much embrittlement. Limitations of the SP test with 0.5 mm thickness for hydrogen damage test for X70 were discussed.

• Journal of Welding and Joining
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• 제32권5호
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• pp.1-6
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• 2014

This study aims at manufacturing SA welded API-X70 line-pipe with sour gas resistance. A pipe was manufactured by JCO bending process and SA welding using the API-X70 plate guaranteed HIC resistance. SA welded pipe was expanded in order to reduce the residual stress. The evaluation of a pipe for resistance to HIC and SSCC were performed by the RS D 0004 and RS D 0005 standards. For verification that a pipe has acceptable resistance to HIC, fullscale test was carried out. Results showed no cracking for the HIC and SSCC.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.525-530
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• 2021

The purpose of this study was to investigate the effect of spherodizing heat treatment holding time on the microstructure and mechanical properties of the accelerated cooling-treated API X70 steel, which is mainly used as a structural material for line pipe steel for natural gas pipes. The accelerated cooling-treated API X70 steel was spherodizing treated at 700℃ for 12~48 h. The microstructure was observed using an OM and a FEG-SEM, and mechanical properties were obtained by tensile test. The microstructure of the API X70 steel was banded in the hot rolling direction, and the polygonal ferrite(PF) adjacent to pearlite(P) has mainly a fine size, and coarse PF and fine acicular ferrite were formed in the middle of P and P. As the spherodizing treatment time increased, the number of carbide particles decreased and its distribution interval increased, and the ferrite grain size was coarsened. The tensile strength decreased and the ductility increased with spherodizing treatment time, and the yield point elongation was disappeared in a stress-strain curve after the spherodizing treatment.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 1993년도 춘계연구발표회 논문개요집
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• pp.66-67
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• 1993

• Elastomers and Composites
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• 제49권2호
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• pp.155-159
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• 2014

1,2-dichlorobenzene용액에서 [$C_{70}$]풀러렌과 3-chloroperoxy benzoic acid 산화반응의 거동을 고분해능 초음파 분광기를 사용하여 고찰하였다. UV-vis spectroscopy, X-ray diffraction을 가지고 [$C_{70}$]풀러렌 산화 반응의 생성물을 확인하였다.

• 한국의학물리학회지:의학물리
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• 제27권4호
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• pp.272-276
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• 2016

To investigate the optimum x-ray tube design for the dental radiology, factors affecting x-ray beam characteristics such as tungsten target thickness and anode angle were evaluated. Another goal of the study was to addresses the anode heel effect and off-axis spectra for different target angles. MCNPX has been utilized to simulate the diagnostic x-ray tube with the aim of predicting optimum target angle and angular distribution of x-ray intensity around the x-ray target. For simulation of x-ray spectra, MCNPX was run in photon and electron using default values for PHYS:P and PHYS:E cards to enable full electron and photon transport. The x-ray tube consists of an evacuated 1 mm alumina envelope containing a tungsten anode embedded in a copper part. The envelope is encased in lead shield with an opening window. MCNPX simulations were run for x-ray tube potentials of 70 kV. A monoenergetic electron source at the distance of 2 cm from the anode surface was considered. The electron beam diameter was 0.3 mm striking on the focal spot. In this work, the optimum thickness of tungsten target was $3{\mu}m$ for the 70 kV electron potential. To determine the angle with the highest photon intensity per initial electron striking on the target, the x-ray intensity per initial electron was calculated for different tungsten target angles. The optimum anode angle based only on x-ray beam flatness was 35 degree. It should be mentioned that there is a considerable trade-off between anode angle which determines the focal spot size and geometric penumbra. The optimized thickness of a target material was calculated to maximize the x-ray intensity produced from a tungsten target materials for a 70 keV electron energy. Our results also showed that the anode angle has an influencing effect on heel effect and beam intensity across the beam.