• Title, Summary, Keyword: 이효석

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Development of Copper and Copper Oxide Removal Technology Using Supercritical CO2 and Hexane for Silicon Solar Cell Recycling (실리콘 태양전지 재자원화를 위한 초임계 CO2 및 헥산을 이용한 구리 및 산화구리 제거기술 개발)

  • Lee, Hyo Seok;Cho, Jae Yu;Heo, Jaeyeong
    • Current Photovoltaic Research
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    • v.7 no.1
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    • pp.21-27
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    • 2019
  • Lifetime of Si photovoltaics modules are about 25 years and a large amount of waste modules are expected to be discharged in the near future. Therefore, the extraction and collection of valuable metals out of discharged Si modules will be one of the important technologies. In this study, we demonstrated that supercritical $CO_2$ extraction method can be effectively used to remove Cu, one of the abundant elements in the module, as well as its oxide form, $Cu_2O$. Especially, we proved that the addition of hexane as co-solvent is effective for the removal of both materials. The optimal ratio of $CO_2$ and hexane was 4:1 at a fixed temperature and pressure of $250^{\circ}C$ and 250 bar, respectively. In addition, it was proven that the removal of $Cu_2O$ was preceded via reduction of $Cu_2O$ to Cu.

This study revises Lee Hyo-seok's The Buckwheat Season, utilizing Novel Corpus, intermediate learners' level (소설텍스트의 난이도 조정 방안 연구 -이효석의 「메밀꽃 필 무렵」을 중심으로-)

  • Hwang, Hye ran
    • Journal of Korean language education
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    • v.29 no.4
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    • pp.255-294
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    • 2018
  • The Buckwheat Season, evaluated as the best of Lee Hyo-seok's literature, is one of the short stories that represent Korean literature. However, vivid literary expressions such as lyrical and beautiful depictions, figurative expressions and dialects, which show the Korean beauty, rather make learners have difficulty and become a factor that fails in reading comprehension. Thus, it is necessary to revise and present the text modified for the learners' language level. The methods of revising a literary text include the revision of linguistic elements such as cryptic vocabulary or sentence structure and the revision of the composition of the text, e.g. suggestion of characters or plot, or insertion of illustration. The methods of revising the language of the text can be divided into methods of simplification and detailing. However, in the process of revising the text, many depend on the adapter's subjective perception, not revising it with objective criteria. This paper revised the text, utilizing by the Academy of Korean Studies, , and the by the National Institute of Korean Language to secure objectivity in revising the text.

Genetic Diversity of Hepatitis C Virus in Korea (한국내 C형 간염바이러스의 유전적 다양성)

  • Kim, Hyun-Sung;Choe, Joon-Ho;Lee, Hyo-Suk
    • The Journal of Korean Society of Virology
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    • v.26 no.1
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    • pp.31-45
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    • 1996
  • C형 간염바이러스 (HCV)는 각 개체간에 뉴클레오티드 서열상의 다양성을 나타내고, 이러한 유전적 다양성이 임상병리적 증상과 밀접한 연관이 있을 것으로 고려되어 왔다. 본 연구에서는 HCV E1과 NS5B 부위의 염기서열 분석을 통해 한국의 C형 간염바이러스의 분포와 다양성에 관해 분석하고, 발생계통도를 그려 HCV간의 진화적 거리를 확인하였다. 염기서열분석은 서울대학교 병원과 충남대학교 병원으로부터 얻은 56개의 HCV-양성 혈청을 대상으로 RT-PCR과 PCR 과정을 통해 얻은 유전자 산물을 클로닝하여 수행되었다. 56개의 혈청중 53개의 샘플에서 HCV RNA가 검출되었다. 이들 53개 샘플에 대한 분석 곁과, 유전형 1a, 1b, 2a, 2b, 7a가 각각 5.7, 45.3, 45.3, 1.9, 1.9%로 분포하고 있고, 1b형과 2a형이 한국에서의 주요한 HCV 유전형으로 밝혀졌다. 본 연구는 염기서열 분석을 통해 한국에서 1b형과 마찬가지로 2a형도 높은 빈도로 분포하고 있고, 비록 분포 빈도는 낮지만 1a 형과 7a 형도 존재하고 있음을 밝힌 최초의 보고이다.

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Modeling of Debonding Detection Using Microstrip Patch Antenna (마이크로스트립 패치 안테나를 이용한 박리 탐사 모델링)

  • Rhim Hong-Chul;Lee Hyo-Seok;Woo Sang-Kyun;Song Young-Chul
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.35-39
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    • 2006
  • With a growing concern about the state of infrastructure worldwide, the demand for the development of reliable nondestructive testing techniques (NDT) is ever increasing. Among possible NDT techniques. microwave method is proven to be effective in fast and non-contact inspection of concrete structures and inclusions inside concrete. It is also found that the microwave method has a potential in detecting the delamination between fiber reinforced polymer (FRP) plate and concrete. On the other hand, ultrasonic method can be another way to find the delamination. In this paper, the research work needed for the development of a reliable microwave method and ultrasonic method is studied in actual measurements of concrete specimens reinforced with FRP. Concrete specimens are made with FRP and artificial delamination inside. A microwave measurement system with horn antennas with high center frequency and broad frequency bandwidth are used to image inside concrete specimens for the detection of debonding. between concrete and FRP. Also, the equipment of ultrasonic method which is commercialized are used at the same condition. Both of the results are analyzed in comparison of each other. Microwave and ultrasonic methods have been used for the detection of debonding between concrete and fiber-reinforced plastic (FRP).

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Development of simple and continuous microwave source using a microwave oven (전자오븐을 이용한 간편하고 연속적인 마이크로파 발생 장치 개발)

  • 권기청;김재현;김정희;이효석;전상진;허승회;최원호
    • Journal of the Korean Vacuum Society
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    • v.9 no.3
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    • pp.290-295
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    • 2000
  • In order to utilize as a pre-ionization means for reproducible ohmic plasma on KAIST-TOKAMAK, a simple, safe, economical and continuous microwave source has been developed using a home kitchen micro-wave oven. The magnetron used in the study can provide 500 W of power at 2.45 GHz. A conventional magnetron in a home kitchen microwave oven generates microwave for 8 ms at every 16 ms periodically due to the periodic (60 Hz) high voltage applied to the magnetron cathode. In order to generate continuous microwave which is suitable for tokamak pre-ionization, the magnetron operation circuit has been modified using a DC high voltage (5 kV, 1 A) power supply. It provides high-voltage with small ripple for magnetron cathode bias. Using the developed magnetron system, electron cyclotron resonace heated (ECH) plasmas were produced and the characteristics of the system were studied by diagnosing the ECH plasma using Langmuir probe and $H_{\alpha}$ emission diagnostics.

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Delamination Detection of FRP Sheet Reinforced Concrete Using Microstrip Patch Antenna (Microstrip Patch Antenna를 이용한 탄소섬유시트 보강콘크리트의 박리 탐사)

  • Rhim, Hong-Chul;Lee, Hyo-Seok;Woo, Sang-Kyun;Song, Young-Chul
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.2
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    • pp.134-141
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    • 2007
  • A series of experimental work has been conducted to evaluate the capability of microstrip patch antenna system in detecting delamination in fiber reinforced Plastic (FRP) sheet reinforced concrete. For that purpose, a prototype microstrip patch antenna was developed with 15 GHz center frequency and 1 GHz bandwidth. For the comparison, a horn antenna with 15 GHz center frequency and 10 GHz bandwidth was used for the measurements of the same specimens. The laboratory sire specimens have the dimensions of 600 mm (length) $\times$ 600 mm (width) $\times$ 50mm (thickness) with a series of delaminations of 300 mm (length) $\times$ 300mm (width) $\times$ 5, 10, 15 mm (thickness). FRP of 1.5 mm thickness and epoxy of 3 mm thickness were placed on the top of artificially created delamination to represent actual FRP reinforced concrete condition. In all cases, the delamination has deen successfully identified. Also, it was shown that imaging results in microstrip patch antenna were improved by signal processing.

A Study on the Firefly-Inspired Distributed Timing Synchronization in Ad Hoc Networks With Packet-Based Communications (패킷 기반 통신을 하는 애드 혹 네트워크에서 반딧불 영감을 받은 분산 타이밍 동기 연구)

  • Yi, Hyo Seok;Kim, Sungjin;Kwon, Dong-Seung;Jang, Sung-Cheol;Kim, Hyeong-Jin;Shin, Won-Yong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.3
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    • pp.575-583
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    • 2013
  • In ad hoc networks, a distributed timing synchronization is studied using a firefly-inspired approach. We illuminate the exiting synchronization algorithm based on the theory of pulse-coupled oscillators so that the algorithm can be applied to multi-carrier systems through packet-based communications, where nodes communicate over an orthogonal frequency-division multiple access air interface. As our main result, we introduce a new sync-code detector, which optimally designs both the coupling function and the detection threshold when various network parameters such as the number of nodes in the network and network topology are given a priori. Computer simulations are performed to show the convergence to a synchronized state in realistic network environments.

Rock Joint Trace Detection Using Image Processing Technique (영상 처리를 이용한 암석 절리 궤적의 추적)

  • 이효석;김재동;김동현
    • Tunnel and Underground Space
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    • v.13 no.5
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    • pp.373-388
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    • 2003
  • The investigation on the rock discontinuity geometry has been usually undergone by direct measurement on the rock exposures. But this sort of field work has disadvantages, which we, for example, restriction of surveying areas and consuming excessive times and labors. To cover these kinds of disadvantages, image processing could be regarded as an altemative way, with additional advantages such as automatic and objective tools when used under adequate computerized algorithm. This study was focused on the recognition of the rock discontinuities captured in the image of rock exposure by digital camera and the production of the discontinuity map automatically. The whole process was written using macro commands builtin image analyzer, ImagePro Plus. ver 4.1(Media Cybernetic). The procedure of image processing developed in this research could be divided with three steps, which are enhancement, recognition and extraction of discontinuity traces from the digital image. Enhancement contains combining and applying several filters to remove and relieve various types of noises from the image of rock surface. For the next step, recognition of discontinuity traces was executed. It used local topographic features characterized by the differences of gray scales between discontinuity and rock. Such segments of discontinuity traces extracted from the image were reformulated using an algorithm of computer decision-making criteria and linked to form complete discontinuity traces. To verify the image processing algorithms and their sequences developed in this research, discontinuity traces digitally photographed on the rock slope were analyzed. The result showed about 75~80% of discontinuities could be detected. It is thought to be necessary that the algorithms and computer codes developed in this research need to be advanced further especially in combining digital filters to produce images to be more acceptable for extraction of discontinuity traces and setting seed pixels automatically when linking trace segments to make a complete discontinuity trace.

Characteristics of Copper Microspheres Grown by Using Mixed-Source Hydride Vapor-Phase Epitaxy (수소화물 기상 성장법에 의해 성장된 마이크로 구리 구슬의 특성)

  • Kim, Kyoung Hwa;Ahn, Ji-Hoon;Ahn, Hyung Soo;Yang, Min;Yi, Sam Nyung;Jeon, Injun;Cho, Chae Ryong;Jeon, Hunsoo;Lee, Jae Hak;Lee, Hyo Suk;Kim, Suck-Whan
    • New Physics: Sae Mulli
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    • v.68 no.10
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    • pp.1052-1058
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    • 2018
  • Single-crystalline copper microspheres were grown at a high temperature of $T=1150^{\circ}C$ for 2 h by using the mixed-source hydride vapor phase epitaxy (HVPE) method in a simplified reactor interlinked in series without any separation between the growth and the source zones. The single-crystalline copper microspheres in the first growth process were grown on a metallic compound graphite substrate composed of 15 wt% copper and 85 wt% carbon by using a graphite boat filled with a mixed source of Al+Ga+Mg in the source zone. The copper microspheres coated by using the mixed source in the second growth process were grown on copper microspheres that had been grown on a quartz substrate with holes at a high temperature of $T=1150^{\circ}C$ for 2 h by using a graphite boat filled with a mixed source of Al+Ga+Mg in the source zone after cooling the single-crystalline copper microspheres. The copper microspheres grown were characterized by using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD).

Hepatitis B Virus DNA Mutation, Pattern of Major Histocompatibility Class-I among Familial Clustered HBV Carriers in Relation to Disease Progression (가족집적성을 보이는 B형간염 바이러스 만성보유자에서 바이러스 유전자의 돌연변이와 주조직접합체 양상 - 질병발현 형태와의 관련성을 중심으로 -)

  • Jung, Seung-Pil;Lee, Hyo-Suk;Kim, Chung-Yong;Ahn, Yoon-Ok
    • Journal of Preventive Medicine and Public Health
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    • v.33 no.3
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    • pp.323-333
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    • 2000
  • Objectives : Chronic HBsAg carriers are the principal source of infection for other susceptible people, and are themselves at high risk of developing serious liver diseases. In Korea, it has been estimated that 65-75% of the HBsAg positives remained as persistent carriers. Additionally, familial clustering of MBV infection has frequently been observed among carriers. Some would become progressive, chronic hepatitis patients, and others would not. The aim of this study was to evaluate the association between various factors, such as the duration of infection, type of virus, mutation of precore/core region in HBV, major histocompatibility class-I, and developing chronic liver diseases among familial HBV carriers. Methods : Chronic carrier status was identified by repeated serological tests for HBsAg at intervals of six months or more. A familial chronic carrier was defined when the disease was observed in a family member over two generations. Two families were recruited, among which a total of 20 chronic HBsAg carriers(11 carriers in No.1, and 9 in No.2 family) were identified. Data on the general characteristics and liver disease status were collected. Identification of the HBV-DNA was successful only for 13 subjects among the 20 carriers. Analysis of viral DNA in terms of subtype, pre-core and core region mutations was carried out. The type of major histocompatibility class-1 for the 13 subjects was also analysed. Results & Conclusions : Seven of 10 chronic HBV carriers of the 1st generation and one of 10 of the 2nd generation were clinical patients with chronic hepatitis, the others, three of the 1 st and nine of the 2nd generation, were asymptomatic carriers. This data indicates that the duration of HBV carriage is one of the major factors for disease severity. The subtype of HBsAg analysed using MBV-DNA identified in 13 carriers were adr, and the pattern of precore nonsense mutation in HBV-DNA was identical among family members, which meads that the same virus strains were transmitted between the family members. The association between the precore or core mutations in HBV-DNA and the disease severity was not observed. While it was suggested that a specific type of MHC class-I may be related to disease progression.

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