• Carbon letters
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• 제23권
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• pp.1-8
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• 2017

Polycrystalline diamond (PCD) tools possessing high hardness and abrasive wear resistance are particularly suited for drilling of carbon fiber reinforced plastic (CFRP) composites, where tool life and consistent hole quality are important. While PCD presents superior performance when drilling CFRP, it is unclear how it performs when drilling multi-stack materials such as CFRP-titanium (Ti) stacks. This comparative study aims to investigate drilling of a Ti plate stacked on a CFRP panel when using PCD tools. The first sequence of the drilling experiments was to drill 20 holes in CFRP only. CFRP-Ti stacks were then drilled for the next 20 holes with the same drill bit. CFRP holes and CFRP-Ti stack holes were evaluated in terms of machined hole quality. The main tool wear mechanism of PCD drills is micro-fractures that occur when machining the Ti plate of the stack. Tool wear increases the instability and the operation temperature when machining the Ti plate. This results in high drilling forces, large hole diameter errors, high surface roughness, wider CFRP exit thermal damage, and taller exit Ti burrs.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.105-106
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• 2020

Recently, a method of deriving an efficient 2D floor plan has been attracting attention for remodeling of old buildings with inaccurate 2D floor plans, and thus, studies on reverse engineering of indoor Point Cloud Date(PCD) have been actively conducted. However, in the case of a indoor PCD, due to interference of indoor objects, available equipment is limited to Mobile Laser Scanner(MLS), which causes a efficiency reduction of data processing. Therefore, this study proposes an automatic derivation algorithm for 2D floor plan of indoor PCD based on pixelation. First, the scanned indoor PCD is projected on the XY coordinate plane. Second, a point distribution of each pixel in the projected PCD is derived using a pixelation. Lastly, 2 floor plan derivation based on the algorithm is performed.

• KSBB Journal
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• 제19권1호
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• pp.50-56
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• 2004

본 연구의 목적은 방향족 화한물인 aniline, benzoate, p-hydroxybenzoate를 분해할 수 있는 Delftia sp. JK-2에서 이들 각 기질에서 배양시 다른 종류의 dioxygenases를 분리 정제하고, 정제된 dioxygenases의 특성을 조사하기 위하여 실시하기 위한 것이다. 기질로서 benzoate, aniline, 또는 p-hydroxybenzoate에 따라 분리된 dioxygenases는 각각 catechol 1,2-dioxygenase (C1 ,2O), catechol 2,3-dioxygenase(C2, 3O), 그리고 protocatechuate 4,5-dioxygenase (4,5-PCD)였다. 각 dioxygenases의 특성을 조사하기 위하여 먼저 benzoate, aniline 또는 p-hydroxybenzoate에서 배양한 Delftia sp. JK-2 세포를 초음파 분쇄기로 파쇄하여, ammonium sulfate precipitation, DEAE-sepharose, 그리고 Q-sepharose의 순서로 정제하여 농축하였다. 정제$.$농축된 dioxygenases의 특이 활성도를 보면 C1, 2O는 3.3 unit/mg, C2, 3O는 4.7unit/mg이고, 4,5-PCD는 2.0 unit/mg이다 C1, 2O와 C2, 3O의 기질 특이성 조사에서는 catechol과 4-methylcatechol에서 두 효소 모두 효소 활성이 나타났으며, C1. 2O에서는 3-methylcatechol에서 약간의 활성이 확인되었고, 4,5-PCD는 protocatechuate에서만 효소 활성을 보여주었다. C1l, 2O와 C2, 3O는 3$0^{\circ}C$와 pH 8.0에서 최적의 활성을 나타내는 것으로 조사되었으며, 4,5-PCD는 3$0^{\circ}C$와 pH 7.0에서 최적의 활성이 조사되었다. Delftia sp. JK-2에서 정제된 C1, 2O와 C2, 3O의 효소활성은 Ag$^{+}$, Hg$^{+}$, 그리고 Cu$^{2+}$에 의해 억제되는 것으로 나타났으며, 4,5-PCD의 경우에는 Ag$^{+}$, Hg$^{+}$, 그리고 Cu$^{2+}$ 뿐만 아니라 Fe$^{3+}$ 에 이해서도 효소 활성이 억제되는 것이 확인되었다. C1, 2O, C2, 3O, 4,5-PCD의 분자량은 SDS-PAGE에 의해 각각 60kDa, 35kDa, 62kDa로 측정되었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.276-279
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• 1995

This paper is re;ated to the splits at the side of chips and the changes of surface roughness according to cutting conditions in precsion cutting. Compared with MCD, the surface roughness of workpiece cut by PCD was inferior at a small feed. But, there were no significant difference between MCD and PCD tool above a certain feed in surface roughness

• Journal of Chest Surgery
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• 제47권1호
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• pp.43-46
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• 2014

Phlegmasia cerulea dolens (PCD) is one of the most critical disorders of acute deep vein thrombosis in that it can cause permanent disability secondary to the compartment syndrome. Although several etiological factors have been proposed, PCD after coronary artery bypass surgery is extremely rare and its definitive pathophysiology is still under debate. We herein present a case of PCD that resulted in the compartment syndrome after coronary artery bypass surgery. Early recognition and decompression of PCD are crucial for saving the affected limbs.

• Archives of Pharmacal Research
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• 제19권2호
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• pp.91-94
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• 1996

In the course of a search for antitumor agents, we found that the extract of Curcuma longa was effective in inducing apoptosis or programmed cell death (PCD) in human myeloid leukemia cells (HL-60). Active compounds for PCD were isolated from the hexanic extraction of the rhizome of Curcuma longa. With the several chromatographies, and spectral data, they were identified as ar-turmerone and $\beta-atlantone$. The present results demonstrate that the exposure of human myeloid leukemia HL-60 cells to clinically achievable concentrations of arturmerone (TU) or .$\beta-atlantone$(AT) produced internucleosomal DNA fragmentation of approximately 200 base-pair multiples, and the morphological changes characteristic of cells undergoing apoptosis or PCD. This findings suggest that these agents may exert their antitumoral activity, in part, through induction of apoptosis(PCD).

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1014-1021
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• 2019

In the bacterial community, unicellular organisms act together as a multicellular being. Bacteria interact within the community and programmed cell death (PCD) in prokaryotes is a sort of altruistic action that enables the whole population to thrive. Genetically, encoded cell death pathways are triggered by DNA damage or nutrient starvation. Given the environmental and bacterial diversity, different PCD mechanisms are operated. Still, their biochemical and physiological aspects remain unrevealed. There are three main pathways; thymineless death, apoptosis-like death, and toxin-antitoxin systems. The discovery of PCD in bacteria has revealed the possibility of developing new antibiotics. In this review, the molecular and physiological characteristics of the three types of PCD and their development potential as antibacterial agents are addressed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.265-266
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• 2013

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.29-30
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• 2010

• 한국정밀공학회지
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• 제17권12호
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• pp.68-75
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• 2000

This paper presents the construction of an ultra-precision machining system and machining experiments using the developed system. The system is composed of air bearing system, granite bed, air pad, and linear feeding mechanism. The cutting conditions have great effect on the surface quality in ultra-precision machining. the ultra-precision machining is mainly processed by several ${\mu}{\textrm}{m}$ depth of cut and feed rate. For this, tools with sharper cutting edge and less tool wear are needed. To satisfy these requirement, diamond is generally used as a tool material for ultra-precision machining. In order to evaluate the cutting characteristics of the PCD and MCD tools on the aluminum alloy, the machining experiments performed using the developed system.