• Journal of the Korean Magnetics Society
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• v.14 no.6
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• pp.228-231
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• 2004

We have studied local magnetization reversal and magnetic properties induced by Laser annealing method in the strip-patterned Ta/NiFe/FeMn/Ta and Ta/NiFe/FeMn/NiFe/Ta multilayers fabricated by ion-beam deposition. The films were exposed to the emission of the DPSS (Diode Pumped Solid State, Nd:YAG) laser under 600 G. The laser beam intensity increased up to 440 mW. When the laser illuminated the patterned film with the power of above 200 m W, the intensity of MR peak located in +87 Oe shrunk. A new MR peak was generated at -63 Oe. When the laser power is 400 mW, the location of positive MR peak(H$\sub$ex/) was changed slightly from +87 Oe to +76 Oe, and the MR ratio was decreased from 0.9% to 0.1 %. On the other hand, the new (negative) MR peak shifted from -63 Oe to -80 Oe, with the MR ratio increased up to 0.3%. As the illuminated area expanded, the intensity of opposite MR peak increased and it of negative MR peak decreased. This proved that the local reversal of exchange biasing should be realized by laser annealing.

• Progress in Medical Physics
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• v.23 no.1
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• pp.33-41
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• 2012

For applying the quality assurance (QA) of volumetric modulated arc therapy (VMAT) introduced in Eulji Hospital, we classify it into three different QA steps, treatment planning QA, pretreatment delivering QA, and treatment verifying QA. These steps are based on the existing intensity modulated radiation therapy (IMRT) QA that is currently used in our hospital. In each QA step, the evaluated items that are from QA program are configured and documented. In this study, QA program is not only applied to actual patient treatment, but also evaluated to establish a reference of clinical acceptance in pretreatment delivering QA. As a result, the confidence limits (CLs) in the measurements for the high-dose and low-dose regions are similar to the conventional IMRT level, and the clinical acceptance references in our hospital are determined to be 3 to 5% for the high-dose and the low-dose regions, respectively. Due to the characteristics of VMAT, evaluation of the intensity map was carried out using an ArcCheck device that was able to measure the intensity map in all directions, $360^{\circ}$. With a couple of dosimetric devices, the gamma index was evaluated and analyzed. The results were similar to the result of individual intensity maps in IMRT. Mapcheck, which is a 2-dimensional (2D) array device, was used to display the isodose distributions and gave very excellent local CL results. Thus, in our hospital, the acceptance references used in practical clinical application for the intensity maps of $360^{\circ}$ directions and the coronal isodose distributions were determined to be 93% and 95%, respectively. To reduce arbitrary uncertainties and system errors, we had to evaluate the local CLs by using a phantom and to cooperate with multiple organizations to participate in this evaluation. In addition, we had to evaluate the local CLs by dividing them into different sections about the patient treatment points in practical clinics.

• Proceedings of the SAREK Conference
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• 2004.11a
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• pp.37-37
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• 2004

• Proceedings of the SAREK Conference
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• 2004.11a
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• pp.38-38
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• 2004

• Korean Journal of Head & Neck Oncology
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• v.7 no.2
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• pp.104-113
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• 1991

선양낭암은 타액선종양중 비교적 드문 악성종양으로 병리조직학적 및 임상적으로 독특한 양상을 보인다. 병리조직학상 종양세포가 신경주변으로 침범하여 수술당시 적절한 수술연을 얻기 어렵고 이에 따른 국소재발이 거듭되고 임파선전이 및 예측치 않는 원격전이가 생기기도 한다. 지금까지 선양낭암환자의 예후에 영향을 미치는 여러 요인들에 대한 연구들이 이루워지고 있는데 그중 조직학적 분화도, 원발부위, 종양의 크기, 수술연의 상태와 임상적 병기들이 중요시되고 있다. 이에 저자들은 1960년부터 1980년 까지 텍사스대학 M.D. Anderson 암센터에서 치료받은 이하선 및 악하선 선양낭암 각각 13례와 26례를 대상으로 원발부위가 환자의 생존 및 치료에 미치는 영향을 알고자 다른 예후인자로 알려진 조직병리학적 소견들과 함께 통계학적 분석을 실시하였다. 이하선과 악하선에 생긴 선양낭암을 비교한 결과 이하선에 생긴 경우 조직학적 분화도가 더 낮았고 악하선 종양에서 수술연에 종양침범율이 더 적었다. 경부 임파절 전이는 악하선 종양에서 많았으나 반면 원격전이는 이하선 종양에서 더 많이 발생하였다. 그러나 종양의 크기, 선경주위침범 유무, 국소재발과 환자의 생존율사이에는 의의있는 상관 관계는 없었다. 이하선과 악하선에 생긴 선양낭암의 여러 특성들과 생존률간의 univariate 분석결과 악하선에 생긴 선양낭암 환자에서 종양이 크거나 조직학상 분화가 나쁘거나(solid pattern), 경부임파절 전이와 원격전이가 생기면 예후에 나쁜 영향을 끼침이 밝혀졌다. 그러나 이하선에 생긴 경우 분석례가 너무 적어 결론을 내리기에 불충분하였다. 원발부위에 따른 선양낭암 환자들의 특성을 chi-square 검정법을 이용하여 통계학적으로 분석한 결과 이 두군간에는 의의있는 통계학적 차이는 발견할 수 없었다.

• Korean Journal of Optics and Photonics
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• v.28 no.3
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• pp.97-102
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• 2017

In this paper, we investigate the optical properties of $Ag@Fe_3O_4$ nanoparticles (NPs) composed of a plasmonic core and a magnetic shell. As the $Fe_3O_4$ shell with high refractive index (~2.42) is formed on the surface of the silver NPs having diameter of 60 nm, the wavelength of the localized surface-plasmon resonance (LSPR) is shifted from 420 nm to 650 nm, a so-called "redshift". Furthermore, through the use of three simulation models ($Ag@Fe_3O_4$ NP, $Fe_3O_4$ shell NP, and silver NP), the peak at 410 nm is seen to be the result of scattering by the $Fe_3O_4$ shell with 60 nm thickness, which would be useful in comprehending the complex optics in various nanoscale assemblies using similar NPs.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.3
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• pp.593-600
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• 2018

Cellular automata (CA) have been applied to effective cryptographic system design. CA is superior in randomness to LFSR due to the fact that its state is updated simultaneously by local interaction. To apply these CAs to the cryptosystem, a study has been performed how to synthesize CA corresponding to given polynomials. In this paper, we analyze the recurrence relations of the characteristic polynomial of the 90 UCA and the characteristic polynomial of the 90/150 CA whose transition rule is <$00{\cdots}001$>. And we synthesize the 90/150 CA corresponding to the trinomials $x^{2^n}+x+1(n{\geq}2)$ satisfying f(x)=f(x+1) using the 90 UCA transition rule blocks and the special transition rule block. We also analyze the properties of the irreducible factors of trinomials $x^{2^n}+x+1$ and propose a 90/150 CA synthesis algorithm corresponding to $x^{2^n}+x^{2^m}+1(n{\geq}2,n-m{\geq}2)$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.625-632
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• 2011

The ignition characteristics of a $CH_4$/hot air counterflow diffusion flame were investigated numerically using a flame-controlling continuation method. For the chemical reactions, the GRI-v1.2 reaction mechanism was used in the simulation. The maximum flame temperature was presented in the space of the inverse global strain rate, and showed S-curve-type behavior. The flame temperatures and velocities of the upper and middle branches were compared for different global strain rates. In addition, the global strain rate was compared with the local strain rates defined at the flame surface and the boundaries of the fuel and oxidizer sides of the fuel/air mixing layer. These local strain rates correlated well with the global strain rate.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.2
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• pp.153-162
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• 1995

The coordinate transformation both WGS84 and Bessel ellipsoids is essential to use of GPS in South Korea. Especially, for transformation considered the needed accuracy and the regional characteristics, the study about geoid modeling and the characteristics on the transformed area should be done. The aim of this study define the characteristics of the transformed coordinates according to transformation methods and the area measured by GPS. For this, large network that include South Korea, four regional network consist of large network, and local net-work include Incheon city designed. Geoid model based on Bessel suitable to South Korea selected from study about the effects of the assumed geoid height at the geodetic origin, and then coefficients computed according as transformed area and methods. Also, the transformed characteristics of the large coefficients, the regional coefficients, and the local coefficients according to methods compared, analyzed synthetically.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.4
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• pp.328-334
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• 2013

The keratocystic odontogenic tumor (KCOT) is a unique cyst because of its locally aggressive behavior, high recurrence rate and characteristic histological appearance. Various options are available for treatment. While some clinicians advocate aggressive forms of dental treatment, others prefer more conservative therapy. In this study, two types of conservative surgical procedures were performed to treat the tumor; marsupialization and cyst enucleation. The patients showed healing process on conservative surgical treatment and teeth erupted without recurrence. Conservative surgical treatment can be an effective treatment option for young children because of their efforts to preserve teeth and other anatomical structures.