• 소성∙가공
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• 제26권2호
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• pp.95-100
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• 2017

In this study, the method of process design for side forming of a tooth part used for a component of automobile transmission was suggested using FE-simulations. To develop the side forming for the tooth part, in this paper, the shape factors of B.T.Pin was considered as design parameters. The shape factors of B.T.Pin were selected to be the round of pin, reinforced angle and reinforced length. Based on FE simulation results, appropriate shape factor without causing any defects was selected. In addition, to increase the strength of pin, the combination of shape factor having minimum stress after side forming was selected using FE-simulation. In addition, with design of a die set, cold side forming of the tooth part was experimented to estimate effectiveness of the designed B.T.Pin. From experiments, it was found that the tooth part with complete formation of the tooth was obtained without making any forming defects and punch fracture.

• 대한한방체열의학회지
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• 제1권1호
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• pp.13-19
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• 2002

Objectives : This study was performed to apply thermography as an method in diagnosis of hwabyung patients. We studied 11 Hwabyung patients who visited to chronic diseases center and circulatory oriental internal medicine of Kangnam oriental medicine hospital and 11 patients control group. Methods : Diagnosis of Hwabyung was based on the dignostic criteria of Hwabyung. The temperature was measured on Chonjung(CV17) Shimsu(B15), Kansu(B18), Kyonjong(G21) in each group. The ${\Delta}T$ was measured between Chonjung(CV17) and Chungjong(CV16), left and right Chungjong(CV16), Shimsu(B15), Kansu(B18), Kyonjong(G21) in each group. We compared the ${\Delta}T$ and DITI types between patients and control group. Results : The ${\Delta}T$ between left and right Chungjong(CV16), Shimsu(B15), Kansu(B18), Kyonjong(G21) were not statistically significant. But the ${\Delta}T$ between Chonjung(CV17) and Chungjong(CV16) was statistically significant(P<0.05) in each group. In control group, DITI type was straight 36%, diamond 27%, multiple small spot 18%, others 18%. In Hwabyung patients group, DITI type was inverse triangle 64%, multiple small spot 9.1%, round 9.1%. Conclusions : The ${\Delta}T$ between Chonjung(CV17) and Chungjong(CV16) and DITI type is considered useful diagnostic methods on Hwabyung patients.

• 대한의생명과학회지
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• 제21권4호
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• pp.172-180
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• 2015

It is well reported that tumor cells can regulate host immune systems. To identify the detailed changes of immune cells between tumor bearing mice and normal mice, we evaluated the systemic immune cell phenotype of B16F10 tumor bearing mice in a time dependent manner. The lymphocytic population (CD4+ and CD8+ T cells) of tumor bearing mice significantly decreased compared to that of normal mice. We found that the Foxp3+CD25+ CD4 T cell decreased, but the Foxp3+$CD25^{high}$ CD4 T cell significantly increased. All subpopulations of CD8 T cells decreased, except the CD62L-CD44+ CD8 T cell subpopulation. The myeloid cell population (CD11b+ and Gr-1+ cells) of tumor bearing mice significantly increased. Specifically, Foxp3+$CD25^{high}$ CD4 T cell and CD11b+Gr-1+ cells significantly increased in early phase of tumor progression. These results are helpful to understand the change of the systemic immune cell subpopulation of tumor bearing mice in a time-dependent manner.

• 한국통신학회논문지
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• 제38B권7호
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• pp.581-588
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• 2013

기본적으로 GMSK는 NRZ 펄스열을 가우시안 저역 통과 필터로 전 처리한 후에 GMSK 신호를 생성하지만, 본 논문에서는 델타 펄스열에 대한 GMSK 변조 시스템을 제안하였다. 제시된 시스템은 바이폴라 델타 펄스로 가우시안 펄스를 발생시키는 가우시안 펄스 생성기, $+T_b/2$와 $-T_b/2$ 사이의 차분기, 그리고 주파수변조 함수를 위한 정합 필터로 구성한다. 기본적인 GMSK 변조와의 비교를 통해 스펙트럼은 40[dB] 감쇠 대역폭에서 약 35[%] 협소하며, 스펙트럼의 중심은 더 낮고, 제로 크로싱 성질이 있는 것으로 나타났다.

• 대한수학회보
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• 제22권2호
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• pp.95-98
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• 1985

In [1], E.B. Lee and L. Markus described a sufficient condition for which the domain of null-controllability of a linear autonomous system is all of R$^{n}$ . The purpose of this note is to extend the result to a certain linear nonautonomous system. Thus we consider a linear control system dx/dt = A(t)x+B(t)u in the Eculidean n-space R$^{n}$ where A(t) and B(t) are n*n and n*m matrices, respectively, which are continuous on 0.leq.t<.inf. and A(t) is a periodic matrix of period .omega.. Admissible controls are bounded measurable functions defined on some finite subintervals of [0, .inf.) having values in a certain convex set .ohm. in R$^{m}$ with the origin in its interior. And we present a sufficient condition for which the domain of null-controllability is all of R$^{n}$ .

• 한국분말재료학회지
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• 제26권4호
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• pp.299-304
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• 2019

Nb-Si-B alloys with Nb-rich compositions are fabricated by spark plasma sintering for high-temperature structural applications. Three compositions are selected: 75 at% Nb (Nb0.7), 82 at% Nb (Nb1.5), and 88 at% Nb (Nb3), the atomic ratio of Si to B being 2. The microstructures of the prepared alloys are composed of Nb and $T_2$ phases. The $T_2$ phase is an intermetallic compound with a stoichiometry of $Nb_5Si_{3-x}B_x$ ($0{\leq}x{\leq}2$). In some previous studies, Nb-Si-B alloys have been prepared by spark plasma sintering (SPS) using Nb and $T_2$ powders (SPS 1). In the present work, the same alloys are prepared by the SPS process (SPS 2) using Nb powders and hypereutectic alloy powders with composition 67at%Nb-22at%Si-11at%B (Nb67). The Nb67 alloy powders comprise $T_2$ and eutectic ($T_2+Nb$) phases. The microstructures and hardness of the samples prepared in the present work have been compared with those previously reported; the samples prepared in this study exhibit finer and more uniform microstructures and higher hardness.

• 한국환경성돌연변이발암원학회지
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• 제22권4호
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• pp.248-254
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• 2002

Single cell gel electrophoresis assay was carried out to evaluate DNA damage in T-and B-lymphocytes from rats exposed to benzene and the correlation between DNA damage and the level of t,t-muconic acids, which are urinary benzene metabolites, was investigated. In control rats, the mean values of Olive tail moments in T-and B-lymphocytes were 1.507$\pm$0.187 and 1.579$\pm$0.206 respectively. DNA damages of T-lymphocytes in rats exposed for 4 weeks showed the highest Olive tail moments at each benzene concentration examined (2.72-4.351). However this DNA damage was decreased after 6 weeks of exposure (1.74-2.09). DNA damages of B-lymphocytes did not show such differences with exposure time or benzene concentration (1.49-2.07) except at 200 ppm at 4 weeks. T-lymphocytes show significantly more damages than B-lymphocyte upon acute exposure to benzene.

• 한국주조공학회지
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• 제15권5호
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• pp.469-476
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• 1995

The effects of Cr, Mo or B additions were investigated on $B2{\leftrightarrow}DO_3$ structural transition temperature $(T_C)$ and mechanical properties of Fe-28at.%Al. The raw materials were arc-melted in vacuum and then subjected to the following heat-treatments to maximize the $DO_3$ ordered structure : $1000^{\circ}C/7days$, slowly cooled to $500^{\circ}C$ and then held for 5 days. In the effect on the grain refinment, the addition of alloying element B was the most effective. The addition of Cr or Mo had little effect. When 1at.%Mo was added, $T_c$ increase about $30^{\circ}C$, but Cr had a very little effect on $T_c$. On the contrary, when B was added, $T_c$ was apt to come down minutely. In the additional effect of alloying element on the mechanical properties, Cr was apt to decrease the microvickers hardness and yield strength, Mo and B didn't have much effect. In the case of compressure strength test, the effect of the environment on the yield strength was contrary to the result of the tensile strength test.

• Progress in Superconductivity
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• 제13권2호
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• pp.105-110
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• 2011

SQUID sensor-based ultra low-field magnetic resonance apparatus with ${\mu}T$-level measurement field requires a strong prepolarization magnetic field ($B_p$) to magnetize its sample and obtain magnetic resonance signal with a high signal-to-noise ratio. This $B_p$ needs to be ramped down very quickly so that it does not interfere with signal acquisition which must take place before the sample magnetization relaxes off. A MOSFET switch-based $B_p$ coil driver has current ramp-down time ($t_{rd}$) that increases with $B_p$ current, which makes it unsuitable for driving high-field $B_p$ coil made of superconducting material. An energy cycling-type current driver has been developed for such a coil. This driver contains a storage capacitor inside a switch in IGBT-diode bridge configuration, which can manipulate how the capacitor is connected between the $B_p$ coil and its current source. The implemented circuit with 1.2 kV-tolerant devices was capable of driving 32 A current into a thick copper-wire solenoid $B_p$ coil with a 182 mm inner diameter, 0.23 H inductance, and 5.4 mT/A magnetic field-to-current ratio. The measured trd was 7.6 ms with a 160 ${\mu}F$ storage capacitor. trd was dependent only on the inductance of the coil and the capacitance of the driver capacitor. This driver is scalable to significantly higher current of superconducting $B_p$ coils without the $t_{rd}$ becoming unacceptably long with higher $B_p$ current.

• Journal of Microbiology and Biotechnology
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• 제30권4호
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• pp.526-532
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• 2020

A bacterial strain, designated B301^T and isolated from raw chicken meat obtained from a local market in Korea, was characterized and identified using a polyphasic taxonomic approach. Cells were gram-negative, non-motile, obligate-aerobic coccobacilli that were catalase-positive and oxidase-negative. The optimum growth conditions were 30℃, pH 7.0, and 0% NaCl in tryptic soy broth. Colonies were round, convex, smooth, and cream-colored on tryptic soy agar. Strain B301^T has a genome size of 3,102,684 bp, with 2,840 protein-coding genes and 102 RNA genes. The 16S rRNA gene analysis revealed that strain B301^T belongs to the genus Acinetobacter and shares highest sequence similarity (97.12%) with A. celticus ANC 4603^T and A. sichuanensis WCHAc060041^T. The average nucleotide identity and digital DNA-DNA hybridization values for closely related species were below the cutoff values for species delineation (95-96% and 70%, respectively). The DNA G+C content of strain B301^T was 37.0%. The major respiratory quinone was Q-9, and the cellular fatty acids were primarily summed feature 3 (C_16:1 ω6c/C_16:1 ω7c), C_16:0, and C_18:1 ω9c. The major polar lipids were phosphatidylethanolamine, diphosphatidyl-glycerol, phosphatidylglycerol, and phosphatidyl-serine. The antimicrobial resistance profile of strain B301^T revealed the absence of antibiotic-resistance genes. Susceptibility to a wide range of antimicrobials, including imipenem, minocycline, ampicillin, and tetracycline, was also observed. The results of the phenotypic, chemotaxonomic, and phylogenetic analyses indicate that strain B301^T represents a novel species of the genus Acinetobacter, for which the name Acinetobacter pullorum sp. nov. is proposed. The type strain is B301^T (=KACC 21653^T = JCM 33942^T).