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Thickness Dependence of Electrical and Optical Properties of ITZO (In-Sn-Zn-O) Thin Films (ITZO (In-Sn-Zn-O) 박막의 전기적 및 광학적 특성의 두께 의존성)

  • Kang, Seong-Jun;Joung, Yang-Hee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.7
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    • pp.1285-1290
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    • 2017
  • We prepared ITZO thin films with various thicknesses on glass substrates using RF magnetron sputtering and investigated electrical, optical and structural properties of the thin film. Sheet resistance of ITZO thin film showed a decreasing trend on the increase of film thickness, but its resistivity exhibited a substantially constant value of $5.06{\pm}1.23{\times}10^{-4}{\Omega}-cm$. Transmittance of ITZO thin film moved to the long-wavelength with the increase of film thickness. Figure of merit in a visible light and an absorption area of P3HT:PCBM organic active layer of the 360nm-thick IZTO thin film was $8.21{\times}10^{-3}{\Omega}^{-1}$ and $9.29{\times}10^{-3}{\Omega}^{-1}$, respectively. Through XRD and AFM measurements, it was confirmed that all the ITZO thin films have amorphous structure and the surface roughness of films are very smooth in the range of 0.561 to 0.263 nm. In this study, it was found that amorphous ITZO thin film is a very promising material for organic solar cell.

The Possibility of Silk Protein to the Chondrogenesis (연골 재생에 대한 실크 단백질의 가능성)

  • Jo, You-Young;Kweon, HaeYong;Lee, Kwang-Gill;Lee, Heui-Sam;Chon, Jeong-Woo
    • Journal of Sericultural and Entomological Science
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    • v.50 no.1
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    • pp.15-19
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    • 2012
  • A number of researcher have studied biomaterials for cartilage regeneration and are now proceeding. Silk protein was attempted for use as biomedical materials by many researchers because it is natural polymer with biocompatibility and excellent mechanical strength. In this study, we want to know a possibility of silk protein on the cartilage regeneration. We isolated chondrocytes from nasal cartilage and confirmed optimal culture condition of the cells. To observe the effects of silk fibroin on chondrogenesis, we added silk fibroin solutions to the culture medium of chondrocyte and detected gene expression levels related chondrogenesis such as col2, col10. The chondrocytes showed optimal growth when they were cultured in DMEM medium supplemented with 10% FBS 100 ${\cdot}{\ddot{I}}$M ascorbic acid. The levels of col2 gene expression were increased in non-autoclaved silk fibroin, but decreased in autoclaved one. Also the gene expression levels of col10 were increased in silk fibroin, particulary at 3D culture. Based on the results of this study, we had seen the possibility of silk fibroin for cartilage regeneration. In future studies, we should know more clearly the relationship between cartilage regeneration and the silk protein.

DOSIMETRY OF ASYMMETRIC COLLIMATIORS (비대칭 콜리메이터의 선량분포 측정)

  • Jeon, Byeong-Chul;Bang, Dong-Wan;Jung, Kap-Soo;Shin, Dong-Bong;Park, Jae-Il
    • The Journal of Korean Society for Radiation Therapy
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    • v.8 no.1
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    • pp.109-114
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    • 1996
  • PURPOSE : To investigate the effect of asymmetric jaws for delivering a uniform accurate dose of radiation to the junctions. METHODS & MATERIALS : A linear accelerator with a set of asymmetric jaws(varian 600C, 2100C, 2100CD with 4mev, 10mev, 10mev). Dose disribution was measured at the junctions with films in phantom. Total $10{\times}20cm^2$ with each $10{\times}10cm^2$ in deviation of ${\pm}1mm$ jaws. RESULTS : Film dosimetry showed the accuracy of asymmetric jaws depending on the machine. CONCLUSION : Understanding the mechanical characteristics of the use of half-beam at the junctions, without hot or cold regions.

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Residual Radioactivity Investigation & Radiological Assessment for Self-disposal of Concrete Waste in Nuclear Fuel Processing Facility (콘크리트 폐기물의 자체처분을 위한 잔류방사능 조사 및 피폭선량평가)

  • Seol, Jeung-Gun;Ryu, Jae-Bong;Cho, Suk-Ju;Yoo, Sung-Hyun;Song, Jung-Ho;Baek, Hoon;Kim, Seong-Hwan;Shin, Jin-Seong;Park, Hyun-Kyoun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.5 no.2
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    • pp.91-101
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    • 2007
  • In this study, domestic regulatory requirement was investigated for self-disposal of concrete waste from nuclear fuel processing facility. And after self-disposal as landfill or recycling/reuse, the exposure dose was evaluated by RESRAD Ver. 6.3 and RESRAD BUILD Ver.3.3 computing code for radiological assessments of the general public. Derived clearance level by the result of assessments for the exposure dose of the general public is 0.1071Bq/g (3.5% enriched uranium) for landfill and $0.05515Bq/cm^2$ (5% enriched uranium) for recycling/reuse respectively. Also, residual radioactivity of concrete waste after decontamination was investigated in this study. The result of surface activity is $0.01Bq/cm^2\;for\;{\alpha}-emitter$ and the result of radionuclide analysis for taken concrete samples from surface of concrete waste is 0.0297Bq/g for concentration of $^{238}U$, below 2w/o for enrichment of $^{235}U$ and 0.0089Bq/g for artificial contamination of $^{238}U$ respectively. Therefore, radiological hazard of concrete waste by self-disposal as landfill and recycling/reuse is below clearance level to comply with clearance criterion provided for Notice No.2001-30 of the MOST and Korea Atomic Energy Act.

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A Countermeasures on Credit Card Crime Using Personal Credit Information (개인신용정보이용 신용카드범죄에 대한 대처방안)

  • Kim, Jong-Soo
    • Korean Security Journal
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    • no.9
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    • pp.27-68
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    • 2005
  • Recently, because credit card crime using a personal credit information is increasing, professionalizing, and spreading the area, the loss occurring from credit card crime is enormous and is difficult to arrest and punish the criminals. At past, crime from forging and counterfeiting the credit card was originated by minority criminals, but at present, the types and appearance of credit card crime is very different to contrasting past crime. The numbers of people using credit card in the middle of 1990's was increasing and barometer of living conditions was evaluated by the number having credit card, therefore this bad phenomenon occurring from credit card crime was affected by abnormal consumption patterns. There is no need emphasizing the importance of personal credit card in this credit society. so, because credit card crime using personal credit card information has a bad effect, and brings the economic loss and harms to individuals, credit card company, and members joining credit card. Credit card crime using personal credit card information means the conduct using another people's credit card information(card number, expiring duration, secret number) that detected by unlawful means. And crime using dishonest means from another people's credit information is called a crime profiting money-making and a crime lending an illegal advance by making false documents. A findings on countermeasures of this study are as follows: Firstly, Diverting user's mind, improving the art of printing, and legitimating password from payment gateway was suggested. Secondly, Complementing input of password, disseminating the system of key-board protection, and promoting legitimations of immediate notification duty was suggested. Thirdly, Certificating the electronic certificates as a personal certificates, assuring the recognition by sense organ of organism, and lessening the ratio of crime occurrence, and restricting the ratio of the credit card crime was suggested.

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The Effects of Ionic Strength on Polytungstate Ions Equilibrium in KCl Solution (다중텅그스텐산 이온평형에 대한 이온세기의 영향. 염화칼륨용액에서)

  • Ahn Sangwoon
    • Journal of the Korean Chemical Society
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    • v.18 no.3
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    • pp.157-170
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    • 1974
  • The effects of ionic strength on the polynucleation reaction of tungstate ions and the protonized reaction of polytungstate ions have been investigated in the range of ionic strength from 1 M to 4 M KCl.The hexatungstate ions and the protonized forms of hexatungstate ions are formed in the tungstate solutions whose ionic strengths are 1 M to 4 M KCl. The equilibrium constants for the formation of hexatungstate ions and the protonized forms of hexatungstate ions are calculated in the range of ionic strength from 1 M to 4M KCl. The enthalpy changes for the formation of hexatungstate ions and the protonized forms of hexatungstate ions are as follows; $7H^++{6WO_4}^{2-}={HW_6O_{21}}^{5-}+3H_2O\;\;{\Delta}H^{\circ}=-62.4{\pm}0.6$$H^++{HW_6O_{21}}^{5-}={H_2W_6O_{21}}^{4-}\;\;{\Delta}H+_1^{\circ}=-4.12{\pm}0.10$$H^++{H_2W_6O_{21}}^{4-}={ H_3W_6O_{21}}^{3-}\;\;{\Delta}H_2^{\circ}=-4.36{\pm}0.30$ The free energy and entropy changes for the above reactions have been also calculated. A linear relation is formed between $log k_{6,7}$ and ionic strength, and $log k_1\;or\;log k_2\;vs{\cdot}{\mu}.$ $log k_{6,7}\;=\;D{\mu}+I,\;\;where\;D\;=\;1.66{\pm}0.02$$log k_1\;=\;D_1{\mu}+I_1,\;\;where\;D_1\;=\;-8.065{\pm}0.001$$log k_2\;=\;D_2{\mu}+I_2,\;\;where\;D_2\;=\;-0.376{\pm}0.006$

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Characteristics and Deposition of CuInS2 film for thin solar cells via sol-gel method0 (Sol-gel법에 의한 박막태양전지용 CuInS2 박막의 증착과 특성)

  • Lee, Sang-Hyun;Lee, Seung-Yup;Park, Byung-Ok
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.4
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    • pp.158-163
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    • 2011
  • $CuInS_2$ thin films were prepared using a sol-gel spin-coating method. That makes large scale substrate coating, simple equipment, easy composition control available. The structural and optical properties of $CuInS_2$ thin films that include less toxic materials (S) instead of Se, tetragonal chalcopyrite structure. Copper acetate monohydrate ($Cu(CH_3COO)_2{\cdot}H2O$) and indium acetate ($In(CH_3COO)_3$) were dissolved into 2-propanol and l-propanol, respectively. The two solutions were mixed into a starting solution. The solution was dropped onto glass substrate, rotated at 3000 rpm, and dried at $300^{\circ}C$ for Cu-In as-grown films. The as-grown films were sulfurized inside a graphite container box and chalcopyrite phase of $CuInS_2$ was observed. To determine the optical properties measured optical transmittance of visible light region (380~770 nm) were less than 30 % in the overall. The XRD pattern shows that main peak was observed at Cu/In ratio 1.0 and its orientation was (112). As annealing temperature increases, the intensity of (112) plane increases. The unit cell constant are a = 5.5032 and c = 11.1064 $\AA$, and this was well matched with JCPDS card. The optical transmittance of visible region was below than 30 %.

Microstructure and Magnetic Properties of Zn1-xCoxO Film Prepared by Pulsed DC Magnetron Sputtering (펄스 DC 마그네트론 스퍼터링법에 의한 Zn1-xCoxO 박막의 미세조직 및 자기적 특성)

  • Ko, Yoon-Duk;Ko, Seok-Bae;Choi, Moon-Soon;Tai, Weon-Pil;Kim, Ki-Chul;Kim, Jong-Min;Soh, Su-Jeung;Kim, Young-Sung
    • Journal of the Korean Ceramic Society
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    • v.42 no.3 s.274
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    • pp.211-217
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    • 2005
  • [ $Zn_{1-x}Co_{x}O$ (x=0-0.3) films were grown on Corning 7059 glasses by asymmetrical bipolar pulsed dc magnetron sputtering. The c-axis orientation along (002) plane was enhanced with increasing Co concentration. The $Zn_{1-x}Co_{x}O$ films are grown with fibrous grains of tight dome shape. The transmittance spectra measured from UV-visible showed that sp-d exchange interactions and typical d-d transitions become activated with increasing Co concentration. The electrical resistivity of $Zn_{1-x}Co_{x}O$ films increased with increasing Co concentration, especially it increased greatly at $30at\% Co. X-ray photoelectron spectroscopy and alternating gradient magnetometer analyses indicated that no Co metal cluster is formed and the ferromagnetic properties are exhibited. The low electrical resistivity and room temperature ferromagnetism of $Zn_{1-x}Co_{x}O$ thin films suggested the possibility of the application to Diluted Magnetic Semiconductors (DMSs).

A REVIEW OF SOME ASPECTS OF THE YELLOWFIN TUNA FISHERY IN THE ATLANTIC OCEAN (대서양 황다랭이의 자원생물학적 연구)

  • CHOO Woo Il
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.10 no.1
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    • pp.37-47
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    • 1977
  • Korea started the Atlantic tuna fishery from 1964 by means of longline, then added bait-boats in 1972. Both fisheries have given the top priority to catch yellowfin tuna(Thunnus albacares). The paper reviews available catch, effort and biological data, estimates some population parameters in order to understand the status of the Atlantic yellowfin tuna as a whole. The main findings are summarized as follows: 1. The total of 476 million hook-equivalent fishing effort was thrown to catch yellowfin tuna in 1974, among which one thired was shared by longliners. 2. The dominant age group becomes younger in both surface and longline fisheries. 3. The recent mortality coefficients were calculated as 1.5 for total mortality and 0.7 for fishing mortality. 4. The weight at recruitment was 2.7 kg in 1973 which was smaller than the regulation size(3.2kg) proposed by ICCAT. 5. The maximum sustained yield was calculated to 95-145 thousand metric tons, which was the level of recent catch. Therefore, it is apparent that the present yellowfin tuna fishery should continue to receive close attention.

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Oceanographic Conditions in Relation to Laver Production in Kwangyang Bay, Korea (광양만의 김 생산과 양식장환경과의 관계에 대하여)

  • HONG Jae-Sang;SONG Choon Bok;KIM Nam-Gil;KIM Jong Man;HUH Hyung Tack
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.20 no.3
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    • pp.237-247
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    • 1987
  • The present study deals with the physico-chemical and meteorological conditions in Porphyra-cultivation ground to determine the relationship between laver production and its environmental factors in Kwangyang Bay from January to April in 1986. As a result, major environmental factors which are thought to have a great influence upon the poor harvest during the cultivation period are as follows; 1) the excessive rainfall in the beginning of cultivation period 2) the accumulation of suspended matters on the thallus of laver 3) the decrease of current velocity and the stagnation of the water in the cultivation ground.

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