신석기시대 입지 환경에 따른 따비의 제작방법 -암사동·운서동 유적 출토품을 중심으로-

김영준 ( Kim¸ Youngjun ) 단국사학회 2020 史學志 Vol.60 No.-

이 글에서는 신석기시대에 구릉지와 충적지 주거지 유적에서 출토되는 따비의 제작기술 차이를 확인하고, 이러한 차이가 왜 나타나는지 살펴보았다. 한강 본류역에는 지형상 구릉지와 충적지에 신석기시대 주거지 유적이 확인되며, 이들 유적에서는 대표적인 뗀석기로 따비가 공통적으로 출토되고 있다. 하지만 지금까지 선행연구들은 따비의 형태분류가 중심이어서 이들 유적 출토 따비를 하나의 범주로 분류하여 입지 환경에 따라 나타나는 다양한 기술적 측면을 소홀히 다루었다. 충적지를 대표하는 암사동 유적 출토 따비의 경우 돌감으로는 돌결면이 발달하지 않은 조직이 치밀한 자갈돌 각섬암과 응회암을 이용하였고, 구릉지를 대표하는 운서동 유적 출토 따비의 경우 돌결면이 매우 발달한 모난돌 편암을 이용하였다. 입지환경 별 따비의 밑감은 암사동 유적의 경우 너비격지를 운서동 유적의 경우 모난돌 조각을 이용하여 따비 제작에 사용하였다. 이러한 제작기술의 차이는 결국 입지환경에 따른 사용방법에 차이, 즉 장착 유무에서 기인하였다고 판단된다. 충적지 유적인 암사동 유적 따비는 장착없이 사용된 도구로 파악되며, 구릉지 유적인 운서동 유적 따비는 목제에 장착하기 위해 만들어진 따비임이 제작기술에서 확인된다. This article explains the technical differences of manufacturing weederplow derived from residential sites located in alluvion or hill areas, and then tries to approach the reason why these differences are made. Neolithic residential sites are confirmed, which are located in alluvion or hill areas of main river valley in Hangang river, and weederplow is one of the representative remains from the sites. However, according to the precedent studies, they did not pay attention to various technical aspects of weederplow because morphological characteristics were the main point. Amphibolite and tuff that have densed and undelveloped surface, were used to make weederplow from Amsadong, which is one of the representative remains in alluvion areas and schist that has developed surface, was used to make weederplow from Unseodong, which is one of the representative remains in hilly areas. In case of Amsadong, flake was used to make weederplow and in Unseo case, debris was used as the raw material. These technical differences could be made by method of use depending on geographical conditions, in other words, With or without mounting is the key. Amsadong weederplow from alluvion areas might be used without equipment, but Unseo weederplow might have the purposed to be equipped with wood and it could be shown in the manufacturing process.

[PC-0012] Pre-study for early detection of Fusarium fujikuroi via fluorescence imaging method

Jaeyoung Kim(Jaeyoung Kim),Younguk Kim(Younguk Kim),Hyeonso Ji(Hyeonso Ji),Songlim Kim(Songlim Kim),Hyoja Oh(Hyoja Oh),Youngjun Mo(Youngjun Mo),Kyunghwan Kim(Kyunghwan Kim),Jeongho Baek(Jeongho Baek) 한국육종학회 2022 한국육종학회 공동학술발표집 Vol.2022 No.-

Electromagnetic Interference (EMI) Transparent Shielding of Reduced Graphene Oxide (RGO) Interleaved Structure Fabricated by Electrophoretic Deposition

Kim, Sanghoon,Oh, Joon-Suk,Kim, Myeong-Gi,Jang, Woojin,Wang, Mei,Kim, Youngjun,Seo, Hee Won,Kim, Ye Chan,Lee, Jun-Ho,Lee, Youngkwan,Nam, Jae-Do American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.20

<P>Here we introduce the electromagnetic shielding effectiveness (SE) of reduced graphene oxide (RGO) sheets interleaved between polyetherimide (PEI) films fabricated by electrophoretic deposition (EPD). Incorporating only 0.66 vol % of RGO, the developed PEI/RGO composite films exhibited an electromagnetic interference shielding effectiveness (EMI SE) at 6.37 dB corresponding to ∼50% shielding of incident waves. Excellent flexibility and optical transparency up to 62% of visible light was demonstrated. It was achieved by placing the RGO sheets in the localized area as a thin film (ca. 20 nm in thickness) between the PEI films (ca. 2 μm) to be an interleaved and alternating structure. This unique interleaved structure without any delamination areas was fabricated by a successive application of cathodic and anodic EPD of both RGO and PEI layers. The EPD fabrication process was ensured by an alternating deposition of the quarternized-PEI drops and RGO, each taking positive and negative charges, respectively, in the water medium. We believe that the developed facile fabrication method of RGO interleaved structure with such low volume fraction has great potential to be used as a transparent EMI shielding material.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-20/am503893v/production/images/medium/am-2014-03893v_0009.gif'></P>

3D Inspection by Registration of CT and Dual X-ray Images

Kim, Youngjun,Kim, Wontae,Lee, Deukhee International Society for Simulation Surgery 2016 Journal of International Society for Simulation Su Vol.3 No.1

Computed tomography (CT) can completely digitize the interior and the exterior of nearly any object without any destruction. Generally, the resolution for industrial CT is below a few microns. The industrial CT scanning, however, has a limitation because it requires long measuring and processing time. Whereas, 2D X-ray imaging is fast. In this paper, we propose a novel concept of 3D non-destructive inspection technique using the advantages of both micro-CT and dual X-ray images. After registering the master object’s CT data and the sample objects’ dual X-ray images, 3D non-destructive inspection is possible by analyzing the matching results. Calculation for the registration is accelerated by parallel computing using graphics processing unit (GPU).

Formation of a functional homo-junction interface through ZnO atomic layer passivation: Enhancement of carrier mobility and threshold voltage in a ZnO nanocrystal field effect transistor

Kim, Youngjun,Chang, Mincheol,Cho, Seongeun,Kim, Minkyong,Kim, Hyunsik,Choi, Eunsoo,Ko, Hyungduk,Hwang, Jinha,Park, Byoungnam Elsevier 2019 JOURNAL OF ALLOYS AND COMPOUNDS Vol.804 No.-

<P><B>Abstract</B></P> <P>We report enhancement of mobility and increase in mobile carrier concentration in zinc oxide (ZnO) nanocrystal (NC) field effect transistors (FETs) through the formation of a homo-junction interface using atomic layer deposition (ALD) passivation. An ultrathin ALD-ZnO passivation film deposited on a ZnO NC film not only increased the FET mobility from 4.6ⅹ10<SUP>−6</SUP> to 1.4ⅹ10<SUP>−4</SUP> cm<SUP>2</SUP>/V but also caused earlier turn-on of the ZnO NC FETs, shifting the threshold voltage from 18.9 to −4.6 V. The enhanced FET mobility and earlier turn-on in the FET are attributed to reduced localized state density on the ZnO NC surface through ALD-ZnO passivation. Passivation of the surface states mitigates carrier depletion in the ZnO NC film through oxygen adsorption on the ZnO surface. We also observed that the presence of saturation of the drain in a high drain-source voltage region depends on the ALD-ZnO passivation and its origin is discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We formed a ZnO-NC/ZnO-ALD planar-homojunction interface, passivating the surface. </LI> <LI> Carrier mobility in the accumulation layer was enhanced by surface passivation. </LI> <LI> Suppression of surface depletion by ALD are crucial in assembling devices. </LI> </UL> </P>

Method to minimize ozone effect on Cy5 fluorescent intensity in DNA microarrays

Kim, Youngjun,Seo, Hyun Hee,Jeong, Mi Seon,Lee, Ki Heon,Lee, In Ho,So, Kyeong A.,Kim, Mi Kyung,Lee, Yoo-Kyung,Kim, Seon Ah,Kim, Tae Jin Elsevier 2017 Analytical Biochemistry Vol.538 No.-

<P><B>Abstract</B></P> <P>Cyanine 5 (Cy5) is an established fluorescent dye in microarray analysis. It is degraded rapidly when exposed to atmospheric ozone during post-hybridization washes, which leads to loss of fluorescent intensity. To minimize this undesirable effect, we coated microarray slides with sodium dodecyl sulfate (SDS) solution at post-hybridization washes. The fluorescent intensities on coated slides were more stable than those on uncoated slide. We also performed the microarrays with SDS solution for a year to check the solution's effectiveness along with seasonal changes of atmospheric ozone level. Consistent results in microarray analysis were obtained using Cy5 dye under atmospheric ozone.</P>

Graphene quantum dot (GQD)-induced photovoltaic and photoelectric memory elements in a pentacene/GQD field effect transistor as a probe of functional interface

Kim, Youngjun,Cho, Seongeun,Kim, Hyeran,Seo, Soonjoo,Lee, Hyun Uk,Lee, Jouhahn,Ko, Hyungduk,Chang, Mincheol,Park, Byoungnam Institute of Physics Publishing Ltd. 2017 Journal of Physics. D, Applied Physics Vol.50 No.36

<P>Electric field-induced charge trapping and exciton dissociation were demonstrated at a penatcene/grapheme quantum dot (GQD) interface using a bottom contact bi-layer field effect transistor (FET) as an electrical nano-probe. Large threshold voltage shift in a pentacene/GQD FET in the dark arises from field-induced carrier trapping in the GQD layer or GQD-induced trap states at the pentacene/GQD interface. As the gate electric field increases, hysteresis characterized by the threshold voltage shift depending on the direction of the gate voltage scan becomes stronger due to carrier trapping associated with the presence of a GQD layer. Upon illumination, exciton dissociation and gate electric field-induced charge trapping simultaneously contribute to increase the threshold voltage window, which can potentially be exploited for photoelectric memory and/or photovoltaic devices through interface engineering.</P>

Highly stable 2D material (2DM) field-effect transistors (FETs) with wafer-scale multidyad encapsulation

Kim, Choong-Ki,Jeong, Eun Gyo,Kim, Eungtaek,Song, Jeong-Gyu,Kim, Youngjun,Woo, Whang Je,Lee, Myung Keun,Bae, Hagyoul,Jeon, Seong-Bae,Kim, Hyungjun,Choi, Kyung Cheol,Choi, Yang-Kyu IOP 2017 Nanotechnology Vol.28 No.5

<P>Field-effect transistors (FETs) composed of 2D materials (2DMs) such as transition-metal dichalcogenide (TMD) materials show unstable electrical characteristics in ambient air due to the high sensitivity of 2DMs to water adsorbates. In this work, in order to demonstrate the long-term retention of electrical characteristics of a TMD FET, a multidyad encapsulation method was applied to a MoS<SUB>2</SUB> FET and thereby its durability was warranted for one month. It was well known that the multidyad encapsulation method was effective to mitigate high sensitivity to ambient air in light-emitting diodes (LEDs) composed of organic materials. However, there was no attempt to check the feasibility of such a multidyad encapsulation method for 2DM FETs. It is timely to investigate the water vapor transmission ratio (WVTR) required for long-term stability of 2DM FETs. The 2DM FETs were fabricated with MoS<SUB>2</SUB> flakes by both an exfoliation method, that is desirable to attain high quality film, and a chemical vapor deposition (CVD) method, that is applicable to fabrication for a large-sized substrate. In order to eliminate other unwanted variables, the MoS<SUB>2</SUB> FETs composed of exfoliated flakes were primarily investigated to assure the effectiveness of the encapsulation method. The encapsulation method uses multiple dyads comprised of a polymer layer by spin coating and an Al<SUB>2</SUB>O<SUB>3</SUB> layer deposited by atomic layer deposition (ALD). The proposed method shows wafer-scale uniformity, high transparency, and protective barrier properties against adsorbates (WVTR of 8?×?10<SUP>−6</SUP> g m<SUP>−2</SUP> day<SUP>−1</SUP>) over one month.</P>

Virtual Reality and Augmented Reality in Plastic Surgery: A Review

Kim, Youngjun,Kim, Hannah,Kim, Yong Oock Korean Society of Plastic and Reconstructive Surge 2017 Archives of Plastic Surgery Vol.44 No.3

Recently, virtual reality (VR) and augmented reality (AR) have received increasing attention, with the development of VR/AR devices such as head-mounted displays, haptic devices, and AR glasses. Medicine is considered to be one of the most effective applications of VR/AR. In this article, we describe a systematic literature review conducted to investigate the state-of-the-art VR/AR technology relevant to plastic surgery. The 35 studies that were ultimately selected were categorized into 3 representative topics: VR/AR-based preoperative planning, navigation, and training. In addition, future trends of VR/AR technology associated with plastic surgery and related fields are discussed.

Improved Sensitivity in Schottky Contacted Two-Dimensional MoS₂ Gas Sensor

Kim, Youngjun,Kang, Sang-Koo,Oh, Nan-Cho,Lee, Hi-Deok,Lee, Soo-Min,Park, Jusang,Kim, Hyungjun American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.42

<P>Two-dimensional (2D) transition-metal dichalcogenides have attracted significant attention as gas-sensing materials owing to their superior responsivity at room temperature and their possible application as flexible electronic devices. Especially, reliable responsivity and selectivity for various environmentally harmful gases are the main requirements for the future chemiresistive-type gas sensor applications. In this study, we demonstrate improved sensitivity of a 2D MoS<SUB>2</SUB>-based gas sensor by controlling the Schottky barrier height. Chemical vapor deposition process was performed at low temperature to obtain layer-controlled 2D MoS<SUB>2</SUB>, and the NO<SUB>2</SUB> gas responsivity was confirmed by the fabricated gas sensor. Then, the number of MoS<SUB>2</SUB> layers was fixed and the types of electrode materials were varied for controlling the Schottky barrier height. As the Schottky barrier height increased, the NO<SUB>2</SUB> responsivity increased, and it was found to be effective for CO and CO<SUB>2</SUB> gases, which had little reactivity in 2D MoS<SUB>2</SUB>-based gas sensors.</P> [FIG OMISSION]</BR>