• Journal of the Korean Magnetics Society
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• v.5 no.2
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• pp.115-118
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• 1995

We predict the magnetization curves with strains in thin films. It is possible to predict the magretoelastic ani¬sotropy erergy which generates the changes of the M-H curves in thin films. We show the prediction of M-H curves in case of isotropic films such as polycrystalline am amorphous thin films as well as single crystal cubic films.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1978.10a
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• pp.208.1-208
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• 1978

Phenol 성 물질이 함유된 산업폐수의 처리와 phenol을 탄소원으로 하는 균체를 이용할 목적으로 공업폐수의 오이로부터 phenol 자화능이 우수한 효모 균주를 선택하여 이 균의 생육에 미치는 환경요인을 조사하였다. 초발 pH 3.5~4.5에서 $35^{\circ}C$ 경우 자화능이 가장 좋았으며 $HgC1_2$ phenylhydrazin $10^{-3}$M 농도에서 완전히 자화능을 잃었다. 배양기 중의 질소원으로 $KNO_3,$ $(NH_2)_2CO가$ 가장 좋았으며 yeast extract 0.01% 첨가하므로써 가장높은 발육효과를 보았다. Phenol을 연속적으로 90시간까지 5회 feeding하며 계속적인 균체증식과 phenol 소모를 보았으며 한편 본균이 catechol, resorcinol도 자화할 수 있다는 점도 알았다.

• Journal of the Korean Magnetics Society
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• v.2 no.3
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• pp.263-267
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• 1992

We have developed new techniques to measure the magnetization and coercivity of a uniaxial magnetic material using a torque magnetometer. The magnetization could be measured from the slope of the linear region in a plot of the torque ${\tau}/H$ versus the applied field H, when the direction of the applied field was normal to the uniaxial orientation. While, the coercivity could be obtained by taking the value of applied field where the torque was zero, when the direction of the applied field was $(180+{\delta})$ degrees from the uniaxial orientation. The techniques were applied to determine the magnetizations and coercivities of several Co /Pd multilayer thin films and the results were confirmed to be similar within a 2 % difference to those obtained by a vibrating sample magnetometer.

• Reproductive and Developmental Biology
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• v.31 no.1
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• pp.29-33
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• 2007

This study was conducted to examine the development of in vitro fertilized (IVF) and nuclear transfer (NT) embryos following vitrification IVF and NT embryos developed to the blastocyst stage were equilibrated by 3 steps, vitrified and thawed, and their survival and hatching rates were examined. In IVF embryos, higher survival (82.1%, 96/117) and hatching rates (64.1%, 75/117) were obtained respectively after thawing and culture in expanded blastocysts compared to blastocysts (p<0.05). High survival and hatching rates were also obtained by vitrification of NT blastocysts, especially in expanded and hatching blastocysts (81.1 and 78.3%, respectively). The result of this study shows that IVF and NT blastocysts, especially late stage blastocysts, are successfully cryopreserved by vitrification.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.4
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• pp.251-257
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• 2023

This study entailed an investigation of a tensile stress measurement method for prestressed concrete (PSC) tendons by utilizing external magnetization. The target of this study are PS structures that have been constructed and in use. An optimal external magnetization based elasto-magnetic (EM) sensor was designed using finite element analysis considering various factors, such as coil arrangement and size, that could influence the PS tendons inside the PSC girder. The residual tensile stress resulting from the external magnetization of the girder was then determined. Further, theoretical verification was performed using the numerical and material data used in the finite element analysis for sensor design. The calculated values of strength of magnetization at the target location were matched with the finite element analysis results. Thus, the designed sensor and the feasibility of magnetizing the tendons inside the PSC I-girder using an EM sensor were validated.

• Journal of the Korean Magnetics Society
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• v.21 no.2
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• pp.48-51
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• 2011

We performed macro-spin simulation studies of the current-induced magnetization reversal of nanomagnetic elements with short current pulses. A special attention was paid to the effect of the energy barrier on the switching current distribution. The switching current and its distribution increase with decreasing the current pulse-width. The relationship between the energy barrier and switching current distribution is described by the Arrhenius-N$\'{e}$el law at a long pulse-width regime. At a regime of short pulse-width, however, the relationship is left unaddressed. The difficulty to address this issue arises because the magnetization switching with a short current pulse is governed not by the thermal activation but by the precession motion. Therefore, an exact formulation for the short pulse regime by solving the Fokker-Plank equation is needed to understand the result.

• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.395-402
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• 1995

The intravoxel spin phases in magnetic resonance imaging (MRI) usually vary due to susceptibility differences of materials to be imaged. The phase variation in the voxel results in a reduction of the signal intensity. This signal intensity reduction is known as the susceptibility effect in MRI and has been studied extensively. In this paper, a new spectral decomposition technique Is proposed and the signal change due to the susceptibility effect can be analyzed. A pulse sequence for the spectral decomposition of the susceptibility was developed and applied to susceptibility imaging of venous blood possessing paramagnetic properties. The computer simulations and their corresponding experimental results obtained using both a phantom and human volunteers are reported. Key words : susceptibility effect in MRI : spectral decomposition of susceptibility effect.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.681-684
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• 2015

Magnetization is very important in the ferro-magnetic physics and provides useful informations in the application field of magnetic devices. Generally, the only first acquired domain pattern is not helpful to recognize domain pattern. Many images are needed to visualize domain pattern through image processing. These images were obtained a 8-bit digital camera. The operation was the subtraction of pixel values of multi domain imanges from the images with 255 of pixel value, which was obtained in the saturated state of magnetic materials. The magnetic domain images was visualized gradually with increasing the number of subtracion operation. LABVIEW was used as an image processing tool and the optic microscope with a polarizer was used in this experiment.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.843-844
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• 2006

자기 기록 시스템이 더 높은 기록 밀도를 가지려면 기록 미디어에 더 작은 공간을 가지는 비트를 기록할 수 있어야 한다. 이를 가능하게 하기 위해서는 더 작은 비트를 보존 할 수 있는 고 보자력 기록 미디어와 이를 기록할 수 있는 자기 기록 헤드가 있어야 한다. 자기 기록 시스템에서 기록 밀도와 함께 중요시 되는 것이 바로 기록 속도이다. 시스템이 발전 할 수록 요구되는 속도 또한 높아지고 있다. 기록 속도가 빨라지려면 기록 주파수가 높아지고 기록 미디어의 회전 속도가 빨라져야 한다. 자기 기록 헤드는 자화되어 있는 고 보자력 기록 미디어 위를 빠른 속도로 직선 운동하고 있는 형태가 되고 이로 인하여 자기 기록 헤드에 와전류가 발생하게 된다. 발생되는 와전류의 형태는 기록 미디어에 자화된 형태에 따라 달라질 것이고 또한 자기 기록 미디어의 회전 속도와 와전류가 발생되는 기록 헤드의 전기전도도에 따라 변화 된다. 본 연구는 이렇게 발생된 와전류를 3차원 유한요소법을 이용하여 분석한 수 이 와전류가 기록 필드에 미치는 영향을 분석하여 제시 하였다.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.131-137
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• 1997

This study was carried out to investigate the in vivo development rates of vitrified-thawed mouse expanding, hatching and hatched blastoc ysts(BL). In vitro fertilization produced blastocysts were vitrified in EFS40(40% ethylene glycol, 30% Ficoll and 0.3 M sucrose in phosphate buffer saline containing 10% FBS). Expanding a and hatching blastocysts were equilibrated in 20% ethylene glyco](EG) for 5 min. before exposure to EFS40 at 25°C for 1 min., they were then vitrified in liquid nitrogen. Hatched blastocysts which cultured in m-CR1 medium supple mented 0.4% bovine serum albumin on day 5. were equilibrated in 10% EG for 5 min. and then vitrified in EFS40 for 30 sec. After thawing, re-expanding blastocysts were transferred to recipients(3 day of pseudopregnant) on one or both uterine horns(6-8 embryos per a horn). Preg¬n nancy rates of recipients and implantation were a assccessed by autopsy on 15 gestation. The res¬u ults obtained in these experiments were summar¬1 ized as follows; 1) The pregnancy and live fetus rates, for vitrified expanding BL(77.8 and 25.0%) and hatching BL(77.8 and 26.4%)n vitro were not significantly difference in those of control BL (66.7 and 42.9%: 83.3 and 40.4%), respectively, 2) in vitro development of vitrified hatched BL was 34.0%. and 3) in vivo developmental rate of vitrified hatched BL was only 33.3%. These results suggested that proposed rapid vitrification p procedures used EFS40 cryoprotectant can be effectively performed in mouse expanding Ihatching blastocysts and that mouse blastocysts a after being hatched from zona pellucida can be successfully cryopreserved.