Insulation Coating of Fe–Si–Cr Soft Magnetic Powder by Selective Oxidation

Jae‑Young Park,Kwangsuk Park,Bosung Seo,Julien O. Fadonougbo,Tae‑Wook Na,Ki Beom Park,Hyeon‑Tae Im,Nong‑Moon Hwang,Hyung‑Ki Park 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

This study examines the insulation coating technology of Fe–Si–Cr powder via selective oxidation annealing, which oxidizeselements selectively by controlling the oxidation potential. The study calculated the oxidation driving force of Fe, Si, andCr, and conducted a thermodynamic analysis of oxidation and reduction conditions according to temperature and oxidationpotential. Based on the results, a selective oxidation annealing was performed in an atmosphere in which Fe is reduced andonly Si and Cr are selectively oxidized. The oxidation potential was controlled through the partial pressure ratio of hydrogenand water vapor. The XPS analysis results confirmed that a Si and Cr complex oxide layer formed on the powder surfaceafter the selective oxidation annealing. Afterward, withstanding voltages were analyzed to evaluate the insulation property. Then, the withstanding voltage of the powder applying the selective oxidation annealing increased significantly comparedto that of the initial powder. Further analysis showed that the powder annealed in an air atmosphere had a significantly lowersaturation magnetic flux density than the initial powder, while the powder applying the selective oxidation annealing hadonly a slightly reduced saturation magnetic flux density.

Ni-Zn-Fe₂O₄의 조성비에 따른 전파흡수특성에 관한 연구

조재원,신용진,조치현,문현욱 明知大學校 産業技術硏究所 1993 産業技術硏究所論文集 Vol.12 No.-

This paper describes a study on absorption properties of electromagnetic wave for the composition ratio of Ni-Zn-Fe₂O₄ Ni-Zn-Fe₂O₄was composed of 48∼51mo1% Fe₂O₃,18~22mol% NiO and 27∼34mo1% ZnO. The sintering of the composition was carried out at 1200℃ for 2 hours. Through the experiments, it was found that the resonance phenomenon occured at low frequency range for high permeability and vice versa. In the case .of the composition of 49mo1% Fe₂O₃,20mo1% NiO and 31mo1% ZnO, the bandwidth ranged from 0. 37GHz to 0.95GHz with the absorption thickness of 10mm. Also, In the case of the composition 51mo1% Fe₂O₃, 22mo1% NiO and 27mo1% ZnO. the bandwidth ranged from 0.45GHz to 1.2GHz with the absorbtion thickness of 6mm. Therefore, it is proved that electromagnetic wave absorbers can be fabricated successfully within the bandwidth range mentioned above.

유구치 I급 와동에서 와동벽 위치와 중합광원에 따른 Microtensile Bond Strength 비교 연구

이현헌,장철호,김영재,김정욱,장기택 대한소아치과학회 2007 大韓小兒齒科學會誌 Vol.34 No.1

이번 실험에서는 중합수축 응력이 가장 크게 나타나는 유구치 I급 와동에서 와동벽의 위치와 중합광원의 변화에 의해 다르게 나타나는 응력의 차이를 microtensile bond strength (MTBS)를 이용하여 알아보는 것을 목적으로 하였다. 교합면 법랑질을 제거한 하악 제 2유구치 30개를 준비하여 I급 와동을 형성하였다. 제조사의 지시에 따라 상아질 접착제를 도포 후 3가지 중합광원: 할로겐 램프, 플라즈마, 발광다이오드를 이용하여 10개씩 광중합하였다. 복합레진을 한꺼번에 충전 후 각각의 중합기로 광중합하였다. 동일 치아에서 각각 치수벽과 축벽의 MTBS 측정용 시편을 제작하고 각 군을 중합광원과 와동벽 위치에 따라 할로겐 램프-축군, 할로겐 램프-치수벽군, 플라즈마-축벽군, 플라즈마-치수벽군, 발광다이오드-축벽군, 발광다이오드-치수벽군의 6개 군으로 분류하였다. 만능시험기에서 MTBS를 측정하고 파절편과 와동의 단면을 SEM을 이용하여 관찰하였다. 동일 중합광원에서 와동벽 간 비교는 T-test, 동일 와동벽에서 중합광원 간 비교는 One-way ANOVA와 Tukey's post hoc test를 이용하였고 Weibull 분포분석을 하였다. 동일 중합광원 군간 비교에서 모두 치수벽 시편의 접착강도가 축벽 시편에 비해 유의하게 높았으며 동일 와동벽 군간 비교에서 모두 중합광원에 따른 접착강도가 유의한 차이를 보이지 않았다. 축벽 시편이 치수벽 시편보다 낮은 Weibull 변수(m)를 나타내었고 SEM 관찰 결과 축벽 시편에서 보다 더 불균일한 접착이 이루어진 것을 알 수 있었다. The purpose of present study was to determine whether different kinds of curing lights can alter microtensile bond strength(MTBS) of class I cavity pulpal and axial wall specimens in primary molar. Thirty clean mandibular 2nd primary molar's occlusal enamel were removed and class I cavity, size of 2×4×2 mm was prepared. Dentin bonding agent was applied according to manufacturer' s manual. Each group was cured with Halogen Curing Unit, Plasma Curing Unit and LED Curing Unit. Composite resin was bulk filled and photo cured with same curing unit. MTBS specimens which size is 0.7×0.7×4 mm were prepared with low speed saw. Specimens were coded by their curing lights and wall positions (Halogen - Axial wall group, Halogen - Pulpal wall group, Plasma - Axial wall group, Plasma - Pulpal wall group, LED - Axial wall group, LED - Pulpal wall group). MTBS were tested at 1 mm/min cross Head speed by Universal Testing Machine. Fractured surface and bonding surface was observed with SEM. T-test between axial and pulpal specimens in each curing lights, one-way ANOVA among different curing light specimens in each wall positions were done. Weibull distribution analysis was done. The results were as follows: Mean MTBS of pulpal wall specimens were significantly greater than that of axial wall specimens at each curing units(p<.05). There was no significant difference in the MTBS among three curing units at axial wall and pulpal wall. In Weibull distribution, pulpal wall specimens were more homogeneous than axial wall specimens.

군에서 값을 갖는 확률분포의 합성

이재원,박성욱,김종헌 金烏工科大學校 産業技術開發硏究院 1999 産業技術開發硏究 Vol.15 No.-

In [1] Bhattacharya has shown that the sequence of the n-fold convolution powers of a probability measure μon a compact connected group G converges in the norm exponentially fast to the normed Haar measure ?? if ?? has a nonzero ??-absolutely continuous part for some κ∈N. Our main purpose in this article is that ??=?? for a symmetirc ??-absolutely continuous probability measure on G.

송과선과 시상하부에서 동시에 발생한 배아종 1예

정재욱,이진호,이수진,하창영,김종수,정윤석,이관우,김현만 대한내분비학회 2000 Endocrinology and metabolism Vol.15 No.4·5

낮은 복압성요누출압을 가진 요실금 환자에서 TVT 술식

백재승,김수웅,구자현,오승준,손환철,박관진,신재욱 대한배뇨장애 및 요실금학회 2003 International Neurourology Journal Vol.7 No.2

위성 ATM 망에서 ABR 서비스를 위한 트래픽 전송방식에 관한 연구

최병석,박재현,박현민,안현석,유재욱 동국대학교 산업기술연구원 1997 산업기술논문집 Vol.9 No.-

ATM의 ABR 서비스는 기본적으로 전달지연이 작은 지상망에 적합하게 개발되었기 때문에 위성 망과 같이 전달지연이 큰 상황에서는 망의 심각한 폭주나 링크의 채널 전송률 저하 등이 발생될 수 있다. 또한 위성채널은 지상 ATM 망에 비해 대역이 제한되어 있으므로 폭주를 미연에 방지하기 위해 보다 치밀하고, 지연에 덜 민감한 대역할당 알고리즘이 필요하다. 본 논문에서는 EPRCA 기반의 위성탑재 ATM 교환기로 구성된 위성 ATM 망에서 BECN과 큐의 상태정보를 이용하여 위성 ATM 망에서 ABR 서비스를 제공할 수 있는 방안을 제안하였다.

박테리오신의 특징과 응용

박진용,주치언,김진욱,이상현,이재화 신라대학교 자연과학연구소 2006 自然科學論文集 Vol.15 No.-

Bacteriocins are antibacterial proteins produced by bacteria that kill or inhibit the growth of other bacteria. Many lactic acid bacteria produce a high diversity of different bacteriocins. Since food safety has become an increasingly important interantional concern, the application of antimicrobial peptides from lactic acid bacteria that target food pathogens without toxic or other adverse effects has received great attention. This article gives an overview of bacteriocin applications, and characteristics.

Case Report : A Large Intrathoracic Meningocele in a Patient with Neurofibromatosis-1

( Jae Wook Jeong ),( Kwang Young Park ),( Sang Min Yoon ),( Du Whan Choe ),( Cheol Hyeon Kim ),( Jae Cheol Lee ) 대한내과학회 2010 The Korean Journal of Internal Medicine Vol.25 No.2

A large intrathoracic meningocele, a saccular protrusion of the meninges through a dilated intervertebral foramen or a bony defect of the vertebral column, was diagnosed in a 41-year-old female patient showing clinical features of neurofibromatosis-1 (NF-1), including cafe-au-lait spots, cutaneous neurofibromas, and axillary frecklings and Lisch nodules on the iris. Her daughter and son also had similar manifestations of NF-1. Regular follow-up with periodic imaging was recommended without surgical treatment because there were no signs or symptoms. Meningocele should be differentiated from posterior mediastinal tumors such as neurofibroma, neuroblastoma, and ganglioneuroma because NF-1 has a high risk of tumor formation. We report on this case with a brief review of the literature. (Korean J Intern Med 2010;25:221-223)

The association between prion proteins and Aβ1-42 oligomers in cytotoxicity and apoptosis

Hyeon, Jae Wook,Kim, Su Yeon,Park, Jun Sun,Choi, Bo Yeong,Lee, Sol Moe,Ju, Young Ran,An, Seong Soo A.,Kim, Chi-Kyeong Elsevier 2012 Biochemical and biophysical research communication Vol.424 No.2

<P>Misfolding of prion protein (PrP to PrPSc) can cause neurodegenerative prion diseases. As a glycosylphosphatidylinositol (GPI)-anchored membrane protein, the normal form of PrP (PrPC) can function as a receptor for ligands in the extracellular space. PrPC was suggested to be involved in memory, synaptic neuronal communication, and anti-oxidation as a neuroprotective agent. The recently identified interaction between PrPC and Aβ(1-42) oligomers suggested another role for PrP as a receptor for Aβ(1-42) oligomers, thereby influencing cytotoxicity and apoptosis. Here, the association between PrPC and Aβ(1-42) oligomers was investigated by visualizing protein localization in neuronal cells by immunocytochemistry. Aβ(1-42) oligomer-induced cytotoxicity was tested in respective expressions of PrPC by using mouse neuroblastoma-2a (N2a) cells, the prion protein overexpressed cells (L2-2B1), and a Prnp-null mouse hippocampal cell line (HpL 3-4). Moreover, apoptotic proteins such as caspase-8 were used to assess the effect of PrPC on Aβ(1-42) oligomer-mediated apoptosis. In L2-2B1 and HpL 3-4 cells, the difference in the cytotoxicity of Aβ(1-42) oligomers could be clearly distinguished. In addition, Aβ(1-42) oligomers induced mitochondria dysfunction, reactive oxygen species (ROS) generation, and calcium influx PrPC-dependently. Apoptosis, related to mitochondria dysfunction, was further investigated to determine the cytotoxic pathway; the results suggest that PrPC could be involved in both the intrinsic and extrinsic apoptotic pathways. Finally, cells with abundant PrPC expression seemed to be more susceptible to Aβ(1-42) oligomer toxicity, suggesting the importance of the level of PrPC expression in the induction of apoptosis.</P>