• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.156-156
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• 2003

수평 전기로에서 ZnIn$_2$S$_4$ 다결정을 합성하여 HWE(Hot Wall Epitaxy)방법으로 2nIn2S4단결정 박막을 반절연성 GaAs(100)기판 위에 성장시켰다. ZnIn2S4 단결정 박막은 증발원의 온도를 610 $^{\circ}C$, 기판의 온도를 450 $^{\circ}C$로 성장시켰고 성장 속도는 0.5 $\mu\textrm{m}$/hr로 확인되었다. ZrIn2S4 단결정 박막의 결정성의 조사에서 10 K에서 광발광(photoluminescence) 스펙트럼이 433 nm (2.8633eV)에서 exciton emission스펙트럼이 가장 강하게 나타났으며, 또한 이중결정 X-선 요동곡선(DCRC)의 반폭치(FWHM)도 133 arcsec로 가장 작아 최적 성장 조건임을 알 수 있었다. Hall 효과는 van der Pauw방법에 의해 측정되었으며, 온도에 의존하는 운반자 농도와 이동도는 293K에서 각각 8.51$\times$$10^{17}$ electron/$cm^{-3}$ 291 $\textrm{cm}^2$/v-s였다. ZnIn2S4 단결정 박막의 광전류 단파장대 봉우리들로부터 10 K에서 측정된 $\Delta$Cr(crystal field splitting)은 0.1678 eV, $\Delta$So(spin orbit coupling)는 0.0148 eV였다. 10 K의 광발광 측정으로부터 고품질의 결정에서 볼 수 있는 free exciton 과 매우 강한 세기의 중성 주개 bound exciton등의 피크가 관찰되었다. 이때 중성 주개 bound exciton의 반치폭과 결합 에너지는 각각 9 meV와 26 meV 였다. 또한 Haynes rule에 의해 구한 불순물의 활성화 에너지는 130 meV 였다.다.

• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.371-383
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• 2017

The aim of this paper is to investigate adjusting process of trade-off relationship between economic growth and income distribution in China which is established by mixed with social and market-oriented economic systems. The characteristic nature of social welfare index in urban and rural regions in China is examined by employing principal component analysis. Empirical evidences reveal that unlike national wide or urban region, the increases of income contribute to improve social well-being in rural region, but not social welfare index. Accordingly, it can be said that although social well-being in rural region seems to be harmful because of weakly organized social welfare index, the potentiality exists to improve social well-being by increased income. Taken all together, the results signifies that the mixed economic system such as China might distribute its increased income appropriately, however, the distributional system is hardly operated to improve social welfare index. And thus the distributional system has to be amended to enhance social well-being in China.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.4
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• pp.179-186
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• 1974

The followings are some results obtained from a series of experiments for the culture of eels from the elver stage in the laboratory from April 1973 to June 1974. 1. The optimum temperature turned out as 30t in the early stage culture. 2. The exponential curve of growth rate for a ten day period at the temperature between $20^{\circ}C$ and $30^{\circ}C$ was represented by the following equation: $$R=0.0056296\;T^{1.80740}$$ 3. The elvers and small eels that were kept improperly for a long time before this experiment also showed the same growth rate, compared with other healthful eels captured directly from the estuarine areas. 4. Those that showed retarded growth among a group of eels during the culture recovered the normal growth rate if graded out and kept in the other aquarium. 5. Feeding rate was not affected when the content of ammonia was less than 5 ppm, but it decreased by half when the content exceeds 6 ppm. 6, The elimination of fecal stuffs and uneaten dispersed feed was very important for the maintaining the water in quality.

• The Journal of the Korea Contents Association
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• v.16 no.7
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• pp.348-358
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• 2016

This study reveals a change in the growth cycle of metropolitan with analyzing the population of Seoul metropolitan area and identifies the characteristics of each urban area. For this, the exponential growth of the city, Roxy index, which in recent years been actively studied in Japan, has applied. As a result, the entire metropolitan area and central areas, and the southern region are about to move to the accelerating centralization phase. In the phase of suburbanization are highly likely to turn into the new phase of regression phase. In addition, the northern and eastern suburbs are currently in progress with the accelerating decentralization phase and are expected to be converted in the decelerating decentralization phase. Through this implication in Seoul metropolitan area, it is necessary to carry out the policy responses about regional maintenance by connecting to the changes in direction and speed of cycle phase of city. The results of this study can be used as basic data to determine the long-term future growth and decline of the metropolitan area.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.406-410
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• 2000

Using the hot-wall epitaxy method, we grew a $Hg_{1-x}Cd_xTe$ (MCT) thin film in-situ after growing (111) CdTe of 9 $mu \textrm{m}$ as a buffer layer. The value of FWHM of double crystal x-ray diffraction rocking curve was 125 arcsec and the surface morphology was clean with a small roughness of 10 nm. From measuring the photocurrent of the grown MCT thin film, the maximum peak wavelength and the cut-off wavelength were 1.1050 $\mu\textrm{m}$ (1.1220 eV) and 1.2632 $\mu\textrm{m}$ (0.9815 eV), respectively. This peak wavelength corresponds to the peak of the band gap due to the intrinsic transition of the photoconductor. Therefore, the MCT thin film could be used as the photoconducting detector sensing a near-IR wavelength band from 1.0 to 1.6 $\mu\textrm{m}$.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.297-297
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• 2012

양자점은 공간적으로 세 방향 모두 전하의 운동을 제한하는 0차원 구조로 불연속적인 상태 밀도를 가진다. 이런 양자점의 특성은 광통신용 소자, 레이저 다이오드 등과 같은 광학 및 전자 장치에 응용될 수 있기 때문에 많은 주목을 받아 활발히 연구되어 왔다. 본 연구에서는 MBE 장비를 이용하여 GaAs 기판위에 InAs 양자점을 성장시키는 동안 As의 공급을 임의로 차단시켜 양자점 형성 조건을 변화시킨 시료들의 광학적 특성을 Photoluminescence (PL) 와 Time-resolved PL (TRPL) 실험을 이용하여 분석하였다. GaAs (001) 기판 위에 GaAs buffer layer를 $610^{\circ}C$에서 성장한 후, $470^{\circ}C$에서 As 공급 조건 변화에 따른 InAs 양자점을 성장하였다. 양자점을 성장한 후 GaAs cap layer를 $610^{\circ}C$에서 성장하였다. InAs 양자점 시료들은 In을 20초 공급하는 동안 As의 공급과 차단을 각각 1초, 2초, 3초의 일정한 간격으로 반복하였다. 10 K에서 각각의 시료들의 PL을 측정한 결과 As 공급과 차단을 2초씩 반복한 T2시료에서 PL 세기가 가장 좋게 나타났으며, 3초씩 반복한 T3시료에서 가장 나쁘게 나타났다. PL 피크는 공급과 차단을 1초씩 반복한 T1 시료가 1.23 eV, T2 시료가 1.24 eV, T3 시료가 1.26 eV에 나타났으며, As의 차단시간이 증가함에 따라 PL 피크가 높은 에너지로 이동함을 보였다. 발광파장에 따른 PL 소멸은 파장이 증가함에 따라 점차 느려지다가 PL 피크 근처에서 가장 느린 소멸곡선을 보이고, 파장이 더 증가하였을 때 점차 빠르게 소멸하였다. As 공급 조건의 변화에 따라 InAs 양자점의 크기와 밀도, 모양 등이 변하는 것을 Atomic Force Microscope (AFM) image를 통하여 확인하였으며, PL과 TRPL을 이용하여 InAs 양자점의 광학적 특성을 분석하였다.

• Applied Chemistry for Engineering
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• v.4 no.1
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• pp.94-102
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• 1993

The effects of temperature and of $Na_2O$ and $SiO_2$ contents on the crystallization of zeolite A were studied, by examining crystallization curves and particle size distributions of final products at various crystallization conditions. Crystallization process could be simulated adopting the assumptions of constant linear growth rate and equilibrium between amorphous solid phase and soluble species. Rate constants were determined by comparing the simulated crystallization curves with experimental data. Rate constant for linear growth increased with temperature and crystallization rate at different mole ratio of $Na_2O/H_2O$ correlated reasonably well with increase of soluble species. The rate constant of crystallization did not increase with increase in mole ratio of $Na_2O/H_2O$, but the rate of nuclei formation and the fraction of soluble species were enhanced. The rate constants for linear growth of zeolite A were determined as $0.07{\sim}0.24{\mu}m{\cdot}min^{-1}$ at these experimental conditions Apparent activation energy was estimated as $49kJ{\cdot}mol^{-1}$.

• Journal of the Korean Ceramic Society
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• v.38 no.1
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• pp.39-44
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• 2001

솔-젤법으로 S $r_{0.9}$B $i_{2.1}$T $a_2$$O_{9}$ stock solution을 합성하고, Ir $O_2$/ $SiO_2$/Si 및 기판 위에 스핀코팅법으로 약 2000$\AA$ 정도의 두께를 가지고 SBT 박막을 제조하였다. Pt/Ti $O_{x}$ 전극을 사용한 SBT 박막과 비교하였을 때 Ir $O_2$전극을 사용한 SBT 박막의 경우 더 낮은 급속 열처리 온도 즉, 72$0^{\circ}C$에서 형석상에서 층상 페롭스카이트 상으로의 상전이가 관찰되었다. 그리고, Ir $O_2$전극을 사용한 SBT 박막은 낮은 열처리에서 결정성장이 이루어졌다. Ir $O_2$전극을 사용한 SBT 박막은 $650^{\circ}C$에서 열처리하였을 때 포화된 이력곡선을 얻었지만, Pt/Ti $O_{x}$ 전극을 사용한 SBT 박막은 $700^{\circ}C$에서 열처리하였을 때 이력곡선이 관찰되었다. Ir $O_2$전극을 사용한 SBT 박막은 $700^{\circ}C$의 열처리에서 8.79 $\mu$C/$ extrm{cm}^2$ (3V)의 2Pr 값을 나타내었다.나타내었다.다.

• Korean Journal of Crystallography
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• v.14 no.1
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• pp.35-38
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• 2003

A simple multistep-concentration setting in capillaries was used to control the water-evaporation rate in vapor-diffusion protein crystallization. In the method used, a variety of evaporation rate curves were obtained by using the secondary precipitant solution referred to as “regulatory solution”, which is not directly exposed to the protein solution. The curves were applied to the crystallization of lysozyme as a model protein. The results clearly showed that crystal growth is dependent on the evaporation rate. Especially, the decoupling curves in which precipitant concentration in protein solutions increases to a certain point and then decreases to the equilibrium concentration gave the best crystals.

• Journal of Korea Technology Innovation Society
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• v.10 no.4
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• pp.654-686
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• 2007

To estimate and analyze an interested science and technology level in any case requires three basic informations: (1) relative positions of our technology level, (2) other relevant technology level of the world best country holding the state of the art technology, and (3) its theoretical or practical maximum level within a certain period of time. Further, additional information from analyzing its respective rate of technology changes is necessary. It seems that most previous empirical or case studies on technology level have not considered third and fourth informations seriously, and thus critically have missed important findings from a dynamic point of view on the matter. A dynamic approach considering types of development processes and paths as well as current position needs an application of a concept of technology development stages and respective growth curves. This paper proposes a new method of approach and application by implementing relatively simple types of the growth curve(S-curve) such as logistic and Comports curves and applying estimation results of these curves to ten core technologies of the growth engines for the next future generation in Korea. The study implies that Korean science and technology level in general clearly gets higher as it approaches to a recent time of period, but relative technology gap from the world best in terms of catching-up period does not get better or narrower in case of at least part of the concerned technologies such as bio new drugs and human organs, and intelligence robots. The possibility does exist that some of our concerned technologies shooting for the next future generation may not come to the world highest level in the near future. The purpose of this study is to propose possibilities of catching-up, if any, by estimating its relevant type of growth pattern by way of measuring and analyzing technology level and by analyzing the technology development process through a position analysis. At this stage this study tries to introduce a new theoretical approach of estimating technology level and its application to existing case study results(data) from Korea Institute of Science and Technology Planning and Evaluation(KISTEP) and Korea Institute of Industrial Technology Evaluation and Planing(ITEP), for years of 2004 and 2006 respectively. The study has some limitations in terms of accuracy of measuring(estimating) a relevant growth curve to a particular technology, feasibility of applying estimated results, accessing and analyzing panel experts opinions. Hence, it is recommended that further study would follow soon enough to verify practical applicability and possible expansion of the study results.