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The study of growth and characterization of $AgInSe_2$ single crystal thin film by hot wall epitaxy (Hot Wall Epitaxy(HWE)에 의한 $AgInSe_2$단결정 박막 성장과 특성에 관한 연구)

  • 홍광준
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.2
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    • pp.197-206
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    • 1999
  • The stochiometric mixture of evaporating materials for the $AgInSe_2$single crystal thin films were prepared from horizontal furnace. Using extrapolation method of X-ray diffraction patterns for the $AgInSe_2$polycrystal, it was found tetragonal structure whose lattice constant $a_0$ and $C_0$ were 6.092 $\AA$ and 11.688 $\AA$, respectively. To obtain the single crystal thin films of AgInSe$_2$, the mixed crystal was deposited on thoroughly etched semi-insulator GaAs(100) substrate by HWE system. The source and substrate temperature were fixed to $610^{\circ}C$ and $450^{\circ}C$ respectively, and the thickness of the single thin films was obtained to 3.8 $\mu\textrm{m}$. The crystallization of single crystal thin films was investigated by the photoluminescence (PL) and double crystal X-ray dirrfaction (DCXD). The Hall effect was measured by the method of van der Pauw and carrier density and mobility dependence on temperature were studied. The carrier density and mobility of $AgInSe_2$single crystal thin films deduced from Hall data are $9.58{\times}10^{22} electron/m^3,\; 3.42{\times}10^{-2}m^2/V{\cdot}s$ at 293 K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the $AgInSe_2$single crystal thin film, the spin orbit coupling $\Delta$So and the crystal field splitting $\Delta$Cr were obtained to 0.29 eV and 0.12 eV at 20 K respectively. From PL peaks measured at 20 K, 881.1 nm (1.4071 eV) and 882.4 nm (1.4051 eV) mean $E_x^U$ the upper polariton and $E_x^L$ the lower polariton of the free exciton $(E_x)$, also 884.1 nm (1.402 eV) express $I_2 peak of donor-bound exciton emission and 885.9 nm (1.3995 Ev) emerges $I_1$ peak of acceptor-bound exciton emission. In addition, the peak observed at 887.5 nm (1.3970 eV) was analyzed to be PL peak due to DAP.

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Photocurrent study on the splitting of the valence band and growth of $ZnIn_{2}Se_{4}$ single crystal thin film by hot wall epitaxy (Hot wall epitaxy(HWE)법에 의한 $ZnIn_{2}Se_{4}$ 단결정 박막 성장과 가전자대 갈라짐에 대한 광전류 연구)

  • Hong, Kwang-Joon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.18 no.5
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    • pp.217-224
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    • 2008
  • A stoichiometric mixture of evaporating materials for $ZnIn_2Se_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $ZnIn_2Se_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were $630^{\circ}C$ and $400^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $ZnIn_2Se_4$ single crystal thin films measured from Hall effect by van der Pauw method are $9.41\times10^{16}cm^{-3}$ and $292cm^2/v{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $ZnIn_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=1.8622eV-(5.23\times10^{-4}eV/K)T^2/(T+775.5K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $ZnIn_2Se_4$ have been estimated to be 182.7 meV and 42.6 meV, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_5$ states of the valence band of the $ZnIn_2Se_4/GaAs$ epilayer. The three photo current peaks observed at 10 K are ascribed to the $A_{1}-$, $B_{1}-exciton$ for n = 1 and $C_{27}-exciton$ peaks for n = 27.

A Study on the ROK Army Leadership for promoting Jointness (합동성 증진을 위한 한국군 리더십 연구)

  • Jin, Jae-Yeoul
    • Korea and Global Affairs
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    • v.1 no.2
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    • pp.209-242
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    • 2017
  • The purpose of this study is to contribute to enhancing spiritual combat power as the core of intangible combat power in Korean armed forces through analyses and suggestions on Admiral Yi Sun-sin's leadership for four major sweeping victories based upon jointness which effectively integrates tangible and intangible combat power in armed forces to maximize the synergy of fighting power. As our armed forces has improved their military structure in the dimension of hardwares so as to enhance their efficiency, according to the results of analyzing the process to promote the jointness between our armed forces and our allied powers in the dimension of softwares supporting such hardware dimensions, it was necessary to innovate the system for reinforcing future-oriented spiritual combat power as well as all the tasks related to leadership as the core of intangible combat power jointly and harmoniously. In order to derive tasks about the leadership of Korean armed forces in the dimension of softwares which should be combined with military structural reform for strengthening spiritual combat power for national defense, this study selected research questions linked with jointness. That is, (1) what is the core of military leadership in Western advanced countries in the age of jointness? (2) What are the contemporary illuminations or implications of Korean leaderships through Admiral Yi Sun-sin's war history? Then, this study analyzed literature reviews, this author's field interviews in the time of war participation, and leadership war history focusing on Admiral Yi Sun-sin's leadership for four major sweeping victories. According to the results of these analyses, this study extracted (1) the strategic leadership to predict and prepare the future, (2) the leadership of integration to create synergy effects, and (3) the leadership of knowledge to be practiced focusing on combats. In addition, in order to reinforce spiritual combat power based upon jointness, (1) it is necessary to precede in-depth and substantial leadership diagnosis for enhancing jointness. (2) It is necessary to embody national defense reform as well as integration for jointness improvement after scientifically comparing and analyzing the differentiation and integration between the Ministry of National Defense, army-navy-air force leadership centers, and PKO centers. (3) It is necessary to promote the merger and abolition between institutions related to intangibale combat power under the Ministry of National Defense.

Effect of University Students' Perceived Organizational Support and Employment Preparation Activities for their Awareness of Good Job (대학생의 조직지원인식과 취업준비활동이 좋은 일자리 인식에 미치는 영향)

  • Bea, Sung-Sook;Chang, Sug-In
    • Management & Information Systems Review
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    • v.36 no.1
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    • pp.59-80
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    • 2017
  • Due to the recent deepening youth unemployment aftereffect, government, companies and universities seek a youth unemployment resolution method and jobs creating measures. But there are indications that the Good Job the university students prefer are limited and sudden rise of the youth unemployment rate mirrors the situation in Japan 20 years ago. Thus, based on the preceding research, this research attempted to perform comparative analysis on Korean and Japanese university students' employment preparation activities and perceived organizational support affect their Awareness of Good Job. To achieve the goal, 2013 GOMS 5,380 copies provided by Korea Employment Information Service are used in the case of Korea and total 5,636 copies within 256 questionnaires targeted to Japanese university students are used in the case of Japan. The results of analysis are as follows. The effect relationship between the perception of organizational support and awareness of Good Job showed a positive influence both in Korea and Japan. The effect relationship between employment preparation activities and awareness of Good Job showed a meaningful effect in Korea whereas it showed no effect in Japan. In the relationship between activities of employment preparation and awareness of Good Job, moderating effect of gender and major field of study didn't show any effect either in Korea or Japan. The results of this research are as follows. First, because it is verified that the support of university has positive influence on the university students' awareness of Good Job, it seems that universities need to intensify the support for the students' welfare enhancement, education satisfaction and the structural support system. Second, the gap of attitude of employment preparation activities and awareness of Good Job between Korea and Japan occurred due to the levels of social structure, welfare and wage differences in the two countries. Therefore, if measures of policy to resolve the welfare and wage gaps between conglomerates and smaller enterprises are enacted, the awareness of younger generations to the Good Job will show a corresponding effect.

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The Current Status of Recycling Process and Problems of Recycling according to the Packaging Waste of Korea (국내 포장 폐기물에 따른 재질별 재활용 공정 현황 및 재활용 문제점)

  • Ko, Euisuk;Shim, Woncheol;Lee, Hakrae;Kang, Wookgeon;Shin, Jihyeon;Kwon, Ohcheol;Kim, Jaineung
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.24 no.2
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    • pp.65-71
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    • 2018
  • Paper packs, glass bottles, metal cans, and plastic materials are classified according to packaging material recycling groups that are Extended Producer Responsibility (EPR). In the case of waste paper pack, the compressed cartons are dissociated to separate polyethylene films and other foreign substance, and then these are washed, pulverized and dried to produce toilet paper. Glass bottle for recycling is provided to the bottle manufacturers after the process of collecting the waste glass bottle, removing the foreign substance, sorting by color, crushing, raw materializing process. Waste glass recycling technology of Korea is largely manual, except for removal of metal components and low specific gravity materials. Metal can is classified into iron and aluminum cans through an automatic sorting machine, compressed, and reproduced as iron and aluminum through a blast furnace. In the case of composite plastic material, the selected compressed product is crushed and then recycled through melt molding and refined products are produced through solid fuel manufacturing steps through emulsification and compression molding through pyrolysis. In the recycling process of paper packs, glass bottles, metal cans, and plastic materials, the influx of recycled materials and other substances interferes with the recycling process and increases the recycling cost and time. Therefore, the government needs to improve the legal system which is necessary to use materials and structure that are easy to recycle from the design stage of products or packaging materials.

Electrode Characteristics of K+ Ion-Selective PVC Membrane Electrodes with AC Impedance Spectrum (AC 임피던스 분석법을 이용한 K+ 이온선택성 PVC막 전극 특성)

  • Kim, Yong-Ryul;An, Hyung-Hwan;Kang, An-Soo
    • Applied Chemistry for Engineering
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    • v.9 no.6
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    • pp.870-877
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    • 1998
  • With impedance spectrum measurements, impedance was studied in the interface between sample solutions for $K^+-ion$ selective PVC membrane electrode containing neutral carriers [dibenzo-18-crown-6 (D18Cr6) and valinomycine (Val)]. Response characteristics of electrode were examined by measuring AC impedance spectra that were resulted from the chemical structure and the content of carrier, variation of plasticizer, membrane thickness, doping of base electrolytes, and concentration variation of sample solution. Transport characteristics of PVC membrane electrode were also studied. It was found that the equivalent circuit for the membrane in $K^+$ solution could be expressed by a series combination of solution resistance and a parallel circuit consisting of the bulk resistance and geometric capacitance of the membrane system. But the charge transfer resistance and Warburg resistance were overlapped a little in the low concentration and low frequency ranges. The carrier, D18Cr6 was best for electrode and impedance characteristics, and ideal electrode characteristics were appeared especially in case of doping of the base electrolyte[potassium tetraphenylborate(TPB)]. The optimum carrier content was about 3.23 wt% in case of D18Cr6 and Val. DBP was best as a plasticizer. As membrane thickness decreased the impedance characteristics was improved, but electrode characteristics were lowered for membrane thickness below the optimum. In the case of D18Cr6, the selectivity coefficients by the mixed solution method for the $K^+$ ion were the order of $NH_4{^+}>Ca^{2+}>Mg^{2+}>Na^+$.

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Strength Properties of Wooden Model Erosion Control Dams Using Domestic Pinus rigida Miller I (국내산 리기다소나무를 이용한 목재 모형 사방댐의 강도 성능 평가 I)

  • Kim, Sang-Woo;Park, Jun-Chul;Lee, Dong-Heub;Son, Dong-Won;Hong, Soon-Il
    • Journal of the Korean Wood Science and Technology
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    • v.36 no.6
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    • pp.77-87
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    • 2008
  • Wooden model erosion control dam was made with pitch pine, of which the strength properties was evaluated. Wooden model erosion control dam was made with diameter 90 mm of pitch pine round posts treated with CUAZ-2 (Copper Azole), changing joint in three different types. In each type, erosion control dam was made in nine floor (cross-bar of five floors and vertical-bar of four floors), of which the hight was 790 mm. And then strength properties were investigated through horizontal loading test and impact strength test, and the deformation of structure through image processing (AICON 3D DPA-PRO system). In horizontal loading test of wooden model erosion control dam using round post of diameter 90 mm, whether there was stone or not did not affect strength much when using self drill screw, but strength was decreased by 23%. In monolithic type of erosion control dam using screw bar, strength was increased by 1.5 times and deformation was decreased when filling with stone. When reinforcing with screw bar that ring is connected to self drill screw, strength was increased by 4.8 times. In impact strength test of wooden model erosion control dam made with round post of diameter 90 mm, the erosion control dam connected with self drilling screw not filling with stone was totally destroyed by the 1st impact, and the erosion control dam using screw bar was ruptured at cross-bar at which 779 kgf of impact was loaded in the 1st impact. In the 2nd impact, the base parts were ruptured, and reaction force was decreased to 545 kgf. In the 3rd impact, whole base parts were destroyed, and reaction force was decreased to 263 kgf.

Growth and Photocurrent Properties of CdIn2S4/GaAs Single Crystal Thin Film by Hot Wall Epitaxy (Hot Wall Epitaxy 법에 의한 CdIn2S4 단결정 박막의 성장과 광전류 특성)

  • Lee, Sang-Youl;Hong, Kwang-Joon;Park, Jin-Sung
    • Journal of Sensor Science and Technology
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    • v.11 no.5
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    • pp.309-318
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    • 2002
  • A stoichiometric mixture of evaporating materials for $CdIn_2S_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CdIn_2S_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were $630^{\circ}C$ and $420^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CdIn_2S_4$ single crystal thin films measured with Hall effect by van der Pauw method are $9.01{\times}10^{16}\;cm^{-3}$ and $219\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CdIn_2S_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=2.7116\;eV-(7.74{\times}10^{-4}\;eV)T^2/(T+434)$. The crystal field and the spin-orbit splitting energies for the valence band of the $CdIn_2S_4$ have been estimated to be 0.1291 eV and 0.0248 eV, respectively, by means of the photocurrent spectra and the Hopfield quasi cubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}5$ states of the valence band of the $AgInS_2$/GaAs epilayer. The three photocurrent peaks observed at 10K areascribed to the $A_1$-, $B_1$-, and C1-exciton peaks for n = 1.

Atmospheric Vertical Structure of Heavy Rainfall System during the 2010 Summer Intensive Observation Period over Seoul Metropolitan Area (2010년 여름철 수도권 집중관측기간에 나타난 호우 시스템의 대기연직구조)

  • Kim, Do-Woo;Kim, Yeon-Hee;Kim, Ki-Hoon;Shin, Seung-Sook;Kim, Dong-Kyun;Hwang, Yoon-Jeong;Park, Jong-Im;Choi, Da-Young;Lee, Yong-Hee
    • Journal of the Korean earth science society
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    • v.33 no.2
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    • pp.148-161
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    • 2012
  • The intensive observation (ProbeX-2010) with 6-hour launches of radiosonde was performed over Seoul metropolitan area (Dongducheon, Incheon Airport, and Yangpyeong) from 13 Aug. to 3 Sep. 2010. Five typical heavy rainfall patterns occurred consecutively which are squall line, stationary front, remote tropical cyclone (TC), tropical depression, and typhoon patterns. On 15 Aug. 03 KST, when squall line developed over Seoul metropolitan area, dry mid-level air was drawn over warm and moist low-level air, inducing strong convective instability. From 23 to 26 Aug and from 27 to 29 Aug. Rainfall event occurred influenced by stationary front and remote TC, respectively. During the stationary frontal rainy period, thermal instability was dominant in the beginning stage, but dynamic instability became strong in the latter stage. Especially, heavy rainfall occurred on 25 Aug. when southerly low level jet formed over the Yellow Sea. During the rainy period by the remote TC, thermal and dynamic instability sustained together. Especially, heavy rainfall event occurred on 29 Aug. when the tropical air with high equivalent potential temperature (>345 K) occupied the deep low-middle level. On 27 Aug. and 2 Sep. tropical depression and typhoon Kompasu affected Seoul metropolitan area, respectively. During these events, dynamic instability was very strong.

Multilateral Approach to forming Air Logistics Hub on North East Asia Region (동북아 항공물류허브을 구축하기 위한 다자적 접근방안)

  • Hong, Seock-Jin
    • The Korean Journal of Air & Space Law and Policy
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    • v.19 no.2
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    • pp.97-136
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    • 2004
  • The Northeast Asian air cargo market has expanded tremendously as a result of the opening up of the Chinese market. The importance of the Asia-Pacific region in the global air transport has also increased. The exchange of human and material resources, services, and information in Northeast Asia, which is expected to increase in the near future, requires that the airlines operating within this region adopt a more liberalized approach. This paper introduced alternatives which can be applied to the Northeast Asian airlines industry so as to bring about the integration of regional air transport: First, this paper found a need for individual Northeast Asian nations to alter their policies towards the airlines industry. Second, each country should further liberalize their respective domestic air transport. Third, there is a need for freer air service agreements to be signed between the nations of Northeast Asia. Fourth, the strategic alliances between the airlines operating in Northeast Asia should be further strengthened. Fifth, this liberalization process should be carried out in an incremental manner, beginning with more competitive airports and routes, or with less-in-demand routes. Sixth, there is a need for a shuttle system to be put into place between the main airports in China, Korea, and Japan. Seventh, these three nations jointly develop aviation safety and security systems that are in accordance with international standards. Eighth, the liberalization process of the aviation industry should be undertaken in conjunction with other related fields. Ninth, organizations linking together civil aviation organization in the Asia-Pacific area should be formed, as should each government linking together. By doing so, these countries will be able to establish regular venues through which to exchange opinions on the integration and liberalization of the air cargo market so as to induce the gradual liberalization of the actual market. The liberalization of the air transport in Northeast Asia will prove to be a daunting task in the short term. However, if the Chinese airlines continue to exhibit continuous growth and Japanese airlines are able to complete their move towards a low-cost structure, this process could be completed earlier than expected. Over the last twenty five years the air transport has undergone tremendous changes. The most important factor behind these changes has been the increased liberalization of the market. As a result, rates have decreased while demand has increased. This has resulted in turning the air transport industry, which was long perceived as an industry in decline, into a high-growth industry. The only method of increasing regional exchanges in the air transport is to pursue further liberalization. The country which implements this liberalization process at the earliest date may very well emerge as a leading force within the air transport industry.

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