Diamond-Like Carbon 코팅을 이용한 금속 장식 용구의 칼라링 및 디자인연구

변건호,김형준,최형우,권도현 한국공예학회 2001 조형디자인연구 Vol.4 No.2

The usual methods of coloring metal ornaments include surface anodizing, plating and painting. However, the anodizing method can apply to AL materials only and the plating method has been causing a severe environmental problem because of the toxicity of materials used. For these methods, surface deteriorations such as decoloration, scratch and corrosion also occur after long-time use. Therefore, a better surface treatment method is needed. This study was conducted to improve corrosion resistance and wear resistance of metal ornaments, and increase their added value by means of the DLC(Diamond-Like-Carbon) coating method, and to expand the range of its application. This study examined the characteristics of the DLC for coloring metal ornaments and the ornamental design for practical application. Coating metal ornaments could be considered as one of promising fields for application of DLC DLC film is very suitable as a coating material because it is an amorphous carbon material based on covalent bond and therefore has excellent hardness, wear resistance, lubricative property, chemical stability and light transmittance. DLC coating film was formed by the PECVD method using 13.56MHz rf plasma and CH4 gas as a material gas. At this time RF power, working pressure, transmittance according to kind and amount of auxiliary gas, and changes in optical band gap were observed. It was shown that the higher the RF power and working pressure, the lower the optical bang gap. This could be demonstrated by observing the amount of carbon-hydrogen bond by means of FT-IR. It was shown that addition of hydrogen and nitrogen would the optical band gap because they serves to break the carbon-hydrogen bond at the time of vapor deposition. The direction of design was set up in the manner that the DLC coating film could be effectively deposited on the surface of an ornament. Design was based on geometric figures and minimalism with plane elements accentuated. Accentuated, partial coating or simple, whole coating was induced by combining quadrangles, triangles and circles basically.

QFD 와 VE를 이용한 DSS의 개발

유일근,임형택 弘益大學校 科學技術硏究所 1997 科學技術硏究論文集 Vol.8 No.-

井水의 微生物學的 水質에 관한 硏究

李建炯 군산대학교 1985 論文集 Vol.10 No.-

Physicochemical and microbiological water qualities of 40 wells located on Okku Gun and Miryong Dong, Kunsan City of Chollabuk Do were examined.The results were as follows; 1.Water temperature and pH were ranged 4.9℃-24℃ and 5.7-8.3 respectively during February to October,1984. 2.The values of dissolved oxygen and biochemical oxygen demand were ranged 2.56-8.55mg/l and 1.0-8.36 mg/l, respectively. 3.The population density of general bacteria was maximized as high as 1.43×104 cell/ml on May, 1984 at Miseong Eup and minimized as low as 2.06×102 cells/l on February, 1984 at Hoehyen-Myon. 4.The population desity of total coliform was ranged 0 - 3.32×103 cells/ml.Maximum density shown on May, but no total coliform was detected on February, 1984. 5.Salmonella & Shigella and Staphylococcus groups grown on selective media were ranged 0-7.47×102 cells/ml, 0-9.2×102 cells/ml, respectively. 6.The water depths of 79% of investigated wells were below 5m, and 52% of wells were 10m from pollutants.

수계환경에서 분변성 오염의 지표로 사용되는 미생물들

이건형 한국환경생물학회 2002 환경생물 : 환경생물학회지 Vol.20 No.3

The direct detection of intestinal pathogens and viruses often requires costly, tedious, and time-consuming procedures. These requirements developed a test to show that the water was contaminated with sewage-borne pathogens by assessing the hygienic quality of water based on indicator microorganisms whose presence indicates that pathogenic microorganisms may also be present. Various groups of microorganisms have been suggested and used as indicator microorganisms. Proposed and commonly used microbial indicators are total coliforms, fecal coliforms, fecal streptococci, Clostridium perfringens, heterotrophic plate count, bacteriophage, and so on. Unfortunately, most, if not all, of these indicators are not ideal because of the sensitivity and resistance to environment stresses and disinfection. However, the development of gene probes and PCR technology may give hope for the discovery of rapid and simple methods for detecting small number of fecal pathogens in various environments.

산림토양내의 병, 해충방제를 위한 생태학적 기초연구 : I.소나무림과 활엽수림내의 지표곤충 1.Soil Surface Insects in Pine Plantation and Oak Forest

이해풍,이건형,김상훈 東國大學校 1989 論文集 Vol.28 No.-

본 연구는 경기도 남양주군 조안면 진중리 소재 동국대학교 연습림의 소나무림과 참나무림 내에서 1987년 5월부터 11월까지 실시되었으며 지표토양곤충군집을 대상으로 종의 구성, 먹이식습성의 구성, 우점종의 구성, 균등도 등이 조사되었다. 조사된 종은 소나무림 내에서 41과 94속 128종으로 확인되었으며 종의 수가 많은 것으로는 딱정벌레목, 벌목, 톡톡히목 그리고 파리목이었고 참나무림의 경우는 46과 95속 135종이었으며 딱정벌레목, 벌목, 톡톡히목 그리고 파리목 순으로 종수가 많았다. 식습성에 따른 영양관계구성은 초식성의 것이 두 지역 모두 가장 많아 소나무팀에서는 전체 절지동물중 43.6%이었고 다음으로 검류를 포함한 포식충류가 37.2% 그리고 잡식성인 것이 19.0%이었다. 한편 참나무림에서는 각각 36.8%, 47.8% 그리고 15.3%를 나타내어 전체적으로는 종의 다양도에서 소나무림이 약간 높았을 뿐 뚜렷한 차이를 볼 수 없었다. 계절별 군집의 변화동태에서는 두 지역간 약간의 차이를 보여서 포식자의 발생밀도가 참나무림에서 9월 중순에 대조적으로 높았을 뿐 큰 차이없이 전체적으로 5-7월에 높았고 9-10월에 낮았다. During the period from May, 1987, to November, 1987, (on the basis of pitfall trap capture,) 128 species and 135 species of insects together with unidentified were collected in soil surface of Pine plantation and Oak forest respectively in Kyounggi-Do. Spiders were most abundant species group, comprising 22.6% of the total number of individuals in Pine plantation. the most abundant insect groups were Coleoptera, Hymenoptera, Collembola and Diptera in Pine plantation, and Coleopteram Hymenoptera and Diptera in Oak forest. Oak forest supported more species than Pine plantation which supported only 4 species at very high population levels and the rest at low levels. Many of the species in two study areas were either general plant feeders or predators. Seasonal abundance of the total insects including spiders was high in the periods of May to July and low in Nomber.

소흑산도의 토양미생물과 해양미생물의 환경적 분포

임병선,이오형,이건형 木浦大學校沿岸生物硏究所 1988 沿岸生物硏究 Vol.5 No.1

The physicochemical properties of soil and the distributions of both soil and marine marine microorganisms of Sohuksan-do, Chonnam were investigated on 22th of May, 1988. The results were as follows: 1. The physicochemical properties of soil 5. investigated sites revealed their pH values ranged 5.0-5.9(mean, 5.52). The values of electroconductivity, organic matter, total nitrogen, and water content were in the range of 140-190 ㎛ho/㎝ , 9.8-18.8%, 1.25-3.62㎎/g , and 27.2-46.5%, respectively. 2. Distribution of soil microbes The total count of bacteria, fungi, and actinomycetes were in the range of 3.0 -8.8 ×10??cells/g soil, 0.7-1.5 ×10??cells/g soil, and 2.0-2.8 ×10?? cells/g soil, respectively. Bacteria occupied about 64.2% of total population, and fungi 9.9%, actinomycetes 26.0%, respectively. Of the total count of each group, cellulolytic bacteria occupied about 13.7% of total bacteria, and celulolytic fungi, about 49.8%, cellulolytic acvtino-mycetes, about 12.2%, respectively. It was worth noting that cellulolytic fungi occupied a large proportion of the total count of fungi, meaning active progress of cellulose decomposition in this area. 3. Distribution of marine microbes The popolarion density of marine bacteria was found to be in the range of 1.07 -4.77 ×10??cells/㎖ at the surface layer, 1.02-7.77 ×10??cells/㎖ in the middle layer, and 2.53 6.58 ×10??cells/㎖ at the bottom layer, respectively. These results showed tendency of higher density at the euphotic zone. In caseof physiologically characteristic bacteria, the population density of proteolytic bacteria was higher than that of either lipolytic or amylolytic bacteria, meaning independence of this area from incorporation of nutrients from outside.

고주파 에너지 절제술로 확인된 중중격 우회로의 전기생리학적 특성

이승환,류종철,김건영,안신기,이문형,김성순 대한순환기학회 1997 Korean Circulation Journal Vol.27 No.7

Ultrafast lithium storage of high dispersed silicon and titanium oxide nanoparticles in carbon

An, Geon-Hyoung,Ahn, Hyo-Jin ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.710 No.-

<P><B>Abstract</B></P> <P>Silicon and carbon composites as an anode material in lithium-ion batteries are the most promising candidates to replace conventional graphite, owing to their synergetic effects of high capacity and excellent mechanical stability. Despite these appealing merits, the significant challenge is directly related to the poor dispersion of Si nanoparticles in the carbon nanofiber (CNF) matrix, leading to a structural collapse after cycling due to the large volume change (∼300%) of Si. Thus, we synthesized unique composites of high-dispersed Si and titanium oxide (TiO<SUB>2</SUB>) nanoparticles in the CNF matrix (Si/TiO<SUB>2</SUB>/CNF) using the complexation of TiO<SUB>2</SUB> nanoparticles in order to the high-dispersed Si nanoparticles. The Si/TiO<SUB>2</SUB>/CNF electrode presents enhanced electrochemical properties including excellent cycling stability and high specific capacity (947 mA h g<SUP>−1</SUP> at 100 mA g<SUP>−1</SUP> after 100 cycles), remarkable high-rate performance (612 mA h g<SUP>−1</SUP> at 2000 mA g<SUP>−1</SUP>), and outstanding ultrafast cycling stability (478 mA h g<SUP>−1</SUP> at 2000 mA g<SUP>−1</SUP> after 100 cycles). It is revealed that the high-dispersed Si nanoparticles can maintain the initial structure after cycling, which definitely demonstrates the superiority of our concept.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High-dispersed Si and TiO<SUB>2</SUB> nanoparticles in the carbon nanofiber. </LI> <LI> Complexation of TiO<SUB>2</SUB> nanoparticles to obtain the high-dispersed Si nanoparticles. </LI> <LI> Effective accommodation of the volume change of Si nanoparticles. </LI> <LI> Shorter diffusion path of Li ions. </LI> <LI> Excellent electrochemical performance as anode for ultrafast lithium storage. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Ultrafast ionic diffusion of debossed carbon nanocomposites for lithium storage

An, Geon-Hyoung,Lee, Young-Geun,Ahn, Hyo-Jin Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.764 No.-

<P><B>Abstract</B></P> <P>Owing to their superb mechanical durability resulting from the dramatic volume changes of the Sn nanoparticles and high electrical conductivity, carbon and tin (Sn) nanocomposites have received an increasing attention in view of their application as anode materials for lithium ion batteries (LIBs). However, due to the poor ionic diffusion capability for Li ions during the cycling, the low ultrafast performance for energy storage remains rather limited. In the present study, aiming to improve the ionic diffusion capability for Li ions, we suggest a novel design of the debossed structure of carbon and Sn nanocomposites by electrospinning, carbonization, and the debossing process. The electrode based on the debossed structure exhibits a noticeable cycling stability and high discharge capacity (677 mA h g<SUP>−1</SUP> after 100 cycles at 100 mA g<SUP>−1</SUP>), an excellent rate capability (482 mA h g<SUP>−1</SUP> at 2000 mA g<SUP>−1</SUP>), and an outstanding ultrafast cycling stability (275 mA h g<SUP>−1</SUP> after 500 cycles at 2000 mA g<SUP>−1</SUP>). Therefore, this novel design of the debossed structure based on carbon and Sn nanocomposites offers attractive effects, such as the effective accommodation of dramatic volume changes for the Sn nanoparticles, as well as an improved ionic diffusion performance of Li ions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Debossed carbon nanocomposites for lithium storage. </LI> <LI> Well-dispersed metal nanoparticles in the carbon matrix. </LI> <LI> Enhanced ionic diffusion ability and competent accommodation of volume change. </LI> <LI> Improved electrochemical performance of ultrafast lithium storage. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Pt Electrocatalysts Composited on Electro-Spun Pt Nanowires for Direct Methanol Fuel Cells

An, Geon-Hyoung,Ahn, Hyo-Jin Materials Research Society of Korea 2012 한국재료학회지 Vol.22 No.8

Two types of Pt nanoparticle electrocatalysts were composited on Pt nanowires by a combination of an electrospinning method and an impregnation method with NaBH4 as a reducing agent. The structural properties and electrocatalytic activities for methanol electro-oxidation in direct methanol fuel cells were investigated by means of scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry. In particular, SEM, HRTEM, XRD, and XPS results indicate that the metallic Pt nanoparticles with polycrystalline property are uniformly decorated on the electro-spun Pt nanowires. In order to investigate the catalytic activity of the Pt nanoparticles decorated on the electro-spun Pt nanowires, two types of 20 wt% Pt nanoparticles and 40 wt% Pt nanoparticles decorated on the electro-spun Pt nanowires were fabricated. In addition, for comparison, single Pt nanowires were fabricated via an electrospinning method without an impregnation method. As a result, the cyclic voltammetry and chronoamperometry results demonstrate that the electrode containing 40 wt% Pt nanoparticles exhibits the best catalytic activity for methanol electro-oxidation and the highest electrochemical stability among the single Pt nanowires, the 20 wt% Pt nanoparticles decorated with Pt nanowires, and the 40 wt% Pt nanoparticles decorated with Pt nanowires studied for use in direct methanol fuel cells.