Heterogeneity of Skin Surface Oxygen Level of Wrist in Relation to Acupuncture Point

Hong, Minyoung,Park, Sarah S.,Ha, Yejin,Lee, Jaegeun,Yoo, Kwangsik,Jhon, Gil-Ja,Suh, Minah,Lee, Youngmi Hindawi Publishing Corporation 2012 Evidence-based Complementary and Alternative Medic Vol.2012 No.-

<P>The distribution of partial oxygen pressure (pO<SUB>2</SUB>) is analyzed for the anterior aspect of the left wrist with an amperometric oxygen microsensor composed of a small planar Pt disk-sensing area (diameter = 25 <I><I>μ</I></I>m). The pO<SUB>2</SUB> levels vary depending on the measurement location over the wrist skin, and they are systematically monitored in the analysis for both one-dimensional single line (along the wrist transverse crease) and two-dimensional square area of the wrist region. Relatively higher pO<SUB>2</SUB> values are observed at certain area in close proximity to the position of acupuncture points with statistical significance, indicating strong relationship between oxygen and acupuncture point. The used oxygen microsensor is sensitive enough to detect the pO<SUB>2</SUB> variation depending on the location. This study may provide information helpful to understand possible physiological roles of the acupuncture points.</P>

High-strength carbon nanotube/carbon composite fibers via chemical vapor infiltration

Lee, Jaegeun,Kim, Teawon,Jung, Yeonsu,Jung, Kihoon,Park, Junbeom,Lee, Dong-Myeong,Jeong, Hyeon Su,Hwang, Jun Yeon,Park, Chong Rae,Lee, Kun-Hong,Kim, Seung Min The Royal Society of Chemistry 2016 Nanoscale Vol.8 No.45

<P>In this study, we have developed an efficient and scalable method for improving the mechanical properties of carbon nanotube (CNT) fibers. The mechanical properties of as-synthesized CNT fibers are primarily limited by their porous structures and the weak bonding between adjacent CNTs. These result in inefficient load transfer, leading to low tensile strength and modulus. In order to overcome these limitations, we have adopted chemical vapor infiltration (CVI) to efficiently fill the internal voids of the CNT fibers with carbon species which are thermally decomposed from gas phase hydrocarbon. Through the optimization of the processing time, temperature, and gas flow velocity, we have confirmed that carbon species formed by the thermal decomposition of acetylene (C2H2) gas successfully infiltrated into porous CNT fibers and densified them at relatively low temperatures (650-750 degrees C). As a result, after CVI processing of the as-synthesized CNT fibers under optimum conditions, the tensile strength and modulus increased from 0.6 GPa to 1.7 GPa and from 25 GPa to 127 GPa, respectively. The CVI technique, combined with the direct spinning of CNT fibers, can open up a route to the fast and scalable fabrication of high performance CNT/C composite fibers. In addition, the CVI technique is a platform technology that can be easily adapted into other nano-carbon based yarn-like fibers such as graphene fibers.</P>

The reason for an upper limit to the height of spinnable carbon nanotube forests

Lee, Jaegeun,Oh, Eugene,Kim, Hye-Jin,Cho, Seungho,Kim, Teawon,Lee, Sunghyun,Park, Junbeom,Kim, Hee Jin,Lee, Kun-Hong Springer-Verlag 2013 JOURNAL OF MATERIALS SCIENCE - Vol.48 No.20

테마파크 자동화 및 예약 시스템 설계

홍석기(Seokgi Hong),임규철(Gyucheol Lim),장재근(Jaegeun Jang),이인지(Ingee Lee),김윤형(Yoonyoung Kim),최예규(Yaekyu Choi),임양원(Yangwon Lim),임한규(Hankyu Lim) 한국정보기술학회 2013 Proceedings of KIIT Conference Vol.2013 No.5

놀이공원은 어린이들이 가장 선호하는 장소이다. 하지만, 놀이기구를 타기 위해서는 많은 시간을 기다려야만 한다. 특히 사람들이 붐비는 휴일에는 놀이기구를 타는 시간보다 대기시간이 길어 시간낭비가 심하다. 본 논문에서는 스마트폰을 이용하여 놀이기구를 타기 위해 대기시간을 줄일 수 있는 시스템을 설계하였다. 스마트폰의 NFC를 이용한 놀이기구 예약 시스템으로 편리하게 이용할 수 있다. Amusement park is a place where children like most. However, in order to get on the ride, you have to wait a lot of time. In particular, the holiday that people are crowded, the waiting time is terrible waste of time longer than the time to ride the ride. In this paper, we designed a system that can reduce the waiting time for using a smartphone. You can conveniently use the theme park reservation system using NFC of smartphone.

The Establishment of Dispersive Radioactive Waste Solidification Devices and Preliminary Performance Evaluation

HyunWook Kang,JaeGeun Lee,YongHo Hong,SnagSu Kwak,DongSik Jin 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

A lot of solid wastes are generated when nuclear power plant is dismantled, and a lot of treatment costs and optimal waste treatment technologies are required to treat the generated solid wastes. Currently, there is no optimized reduction and solidification technology for each characteristics of radioactive dismantling waste, so the customized treatment technology for each waste is required to respond actively to this issue. This paper shows the evaluation results of molding and sintering characteristics using preliminary sample to derive operational characteristics and improvements for powder mixing device, molding device, and sintering device manufactured for solidification of dispersible radioactive waste. Zeolite was used as a preliminary sample for performing basic operation characteristics evaluation of each unit device. First of all, the basic operation characteristics of the powder mixing device was evaluated by analyzing the sample distribution, mixing degree, and tap density. It was confirmed that the preliminary sample was well mixed in all areas of the cylinder where the mixing was performed. In the tap density analysis, the increase effect of the volume reduction of the sample was confirmed according to the increase of the RPM speed (up to 2000 RPM). Since the particle size of zeolite sample is very small (nanometer size), the particular consistency of the change of average particle size with RPM speed couldn’t be confirmed, but the uniform of particle size distribution was confirmed with RPM speed size. The basic operation characteristics of the molding device was evaluated for each mold size (ID30, ID50, ID100) according to the moisture content (0-20%) and the molding pressure condition (25-200 MPa) for the preliminary sample. In the characteristics evaluation of the sintered body, the strength of the sintered body was much higher than that of the molded body. However, it was confirmed that as moisture evaporated during the sintering process according to the moisture content contained in the molded body, the swelling occurred in the sintered body due to vapor pressure, and this caused cracks in the longitudinal or transverse direction inside and outside the sintered body. Therefore, optimal moisture content conditions for sintering should be derived. In conclusion, if the operation characteristics and improvements of powder mixing, molding and sintering devices derived from this study are reflected and improved, it is judged that it is possible to derive the optimal process for solidification of dispersive radioactive wastes.

Mathematical model for the dynamic mechanical behavior of carbon nanotube yarn in analogy with hierarchically structured bio-materials

Park, Junbeom,Lee, Jaegeun,Lee, Dong-Myeong,Lee, Sung-Hyun,Jeong, Hyeon Su,Lee, Kun-Hong,Kim, Seung Min Elsevier 2019 Carbon Vol.152 No.-

<P><B>Abstract</B></P> <P>The mechanical behaviors of carbon nanotube yarn (CNTY) can be described as collective mechanical behaviors of the components that comprise its hierarchical structures. The internal structures and mechanical behaviors of CNTYs closely resemble those of bio-materials, so we developed a simple mathematical model inspired by the mechanical behaviors of bio-materials to fully describe the mechanical behaviors of CNTYs during tensile testing. The developed model successfully fitted the experimental modulus-strain (M-S) curves of four types of CNTYs that have different internal structures and different M-S curves; this result confirms the generality of the model to describe the mechanical behaviors of CNTYs. The model parameters provide explanations of the structural characteristics of various CNTYs.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microwave heating of carbon-based solid materials

Kim, Teawon,Lee, Jaegeun,Lee, Kun-Hong 한국탄소학회 2014 Carbon Letters Vol.15 No.1

As a part of the electromagnetic spectrum, microwaves heat materials fast and efficiently via direct energy transfer, while conventional heating methods rely on conduction and convection. To date, the use of microwave heating in the research of carbon-based materials has been mainly limited to liquid solutions. However, more rapid and efficient heating is possible in electron-rich solid materials, because the target materials absorb the energy of microwaves effectively and exclusively. Carbon-based solid materials are suitable for microwave-heating due to the delocalized pi electrons from sp2-hybridized carbon networks. In this perspective review, research on the microwave heating of carbon-based solid materials is extensively investigated. This review includes basic theories of microwave heating, and applications in carbon nanotubes, graphite and other carbon-based materials. Finally, priority issues are discussed for the advanced use of microwave heating, which have been poorly understood so far: heating mechanism, temperature control, and penetration depth.

Turning refuse plastic into multi-walled carbon nanotube forest

Oh, Eugene,Lee, Jaegeun,Jung, Seung-Ho,Cho, Seungho,Kim, Hye-Jin,Lee, Sung-Hyun,Lee, Kun-Hong,Song, Kyong-Hwa,Choi, Chi-Hoon,Han, Do Suck Elsevier 2012 Science and technology of advanced materials Vol.13 No.2

<P>A novel and effective method was devised for synthesizing a vertically aligned carbon nanotube (CNT) forest on a substrate using waste plastic obtained from commercially available water bottles. The advantages of the proposed method are the speed of processing and the use of waste as a raw material. A mechanism for the CNT growth was also proposed. The growth rate of the CNT forest was ~2.5 μm min<SUP>−1</SUP>. Transmission electron microscopy images indicated that the outer diameters of the CNTs were 20–30 nm on average. The intensity ratio of the G and D Raman bands was 1.27 for the vertically aligned CNT forest. The Raman spectrum showed that the wall graphitization of the CNTs, synthesized via the proposed method was slightly higher than that of commercially available multi-walled carbon nanotubes (MWCNTs). We expect that the proposed method can be easily adapted to the disposal of other refuse materials and applied to MWCNT production industries.</P>

Selective Synthesis of SiC and SiO_<i>x</i>Nanowires by Direct Microwave Irradiation

Oh, Eugene,Jung, Seung-Ho,Lee, Jaegeun,Cho, Seungho,Kim, Hye-Jin,Lee, Bo-Ram,Lee, Kun-Hong,Song, Kyong-Hwa,Choi, Chi-Hoon,Han, Do-Suck IOP Publishing 2011 Japanese journal of applied physics Vol.50 No.r2

멀티채널 오디오 서비스를 위한 지상파 DMB 미디어처리기 설계

강경옥,홍재근,서정일,Kang Kyeongok,Hong Jaegeun,Seo Jeongil 한국음향학회 2005 韓國音響學會誌 Vol.24 No.4

지상파 디지털멀티미디어방송 (Terrestrial Digital Multimedia Broadcasting, T-DMB)은 7인치 화면에서 VCD급의 고화질 비디오와 CD급의 고품질 오디오를 이동수신 환경에서 제공하는 기술로서, 2005년도 중반부터 상용 서비스가 시작될 예정이다. 그러나, T-DMB 규격에서는 가용 대역폭의 제한으로 인하여 오디오 신호를 위한 대역폭이 128kbps로 제한되어 있으며, 모노와 스테레오 채널 서비스만이 가능하도록 하고 있다. 본 논문은 기존의 T-DMB 수신기과 역호환성 (Backward Compatibility)을 유지하면서 멀티채널 오디오 콘텐츠를 제공할 수 있는 미디어처리기와 재생기 구조를 제안한다. 또한, T-DMB수신기의 다양한 스피커 환경에서도 최적의 오디오 콘텐츠를 제공할 수 있도록, 멀티채널 오디오 콘텐츠를 재생환경에 맞게 적응시킬 수 있는 수신기 구조를 제안한다. 기존의 T-DMB 수신기와 호환성을 유지하면서 멀티채널 오디오 콘텐츠를 제공하기 위하여 멀티채널 오디오를 위한 부가데이터를 메인 오디오 스트림의 종속 스트림으로 정의하였으며, 기존 T-DMB 시스템의 BIFS (Binary Format for Scene)를 수정하지 않고 부가되는 오디오 객체를 제어할 수 있는 OD (Object Descriptor) 구조를 제안한다. The Terrestrial Digital Multimedia Broadcasting (T-DMB) system supplies high quality audio comparable with VCD in 7 inch display and high quality audio comparable CD at the mobile reception environment T-DMB will launch commercial service at the middle of 2005. However the bandwidth for audio data and the number of channels are restricted to 128 kbps and 2 respectively in the current T-DMB standard because of the limitation of available bandwidth for multimedia data. This Paper Proposes a novel media processor structure for providing multi-channel audio contents oyer T-DMB system allowing backward compatibility with the legacy T-DMB receiver. Furthermore. we also Propose an adaptive receiver structure to supply optimal audio contents on various speaker configuration in T-DMB receiver. To provide multi-channel audio contents allowing backward comaptilbity with the legacy T-DMB receiver, the additional data for multi-channel audio are defined as a dependent stream of main audio stream. The OD strucure for control an additional multi-channel audio elementary stream is proposed without changing the BIFS of the legacy T-DMB system.