• Title/Summary/Keyword: T. B. Lee

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Temperature and magnetic field dependent optical properties of superconducting $MgB_2$ thin film (초전도 $MgB_2$ 박막의 온도와 장기장의 변화에 따른 광학적 성질)

  • Jung, J. H.;Lee, H. J.;Kim, K. W.;Kim, M. W.;Noh, T. W.;Wang, Y. J.;Kang, W. N.;Jung, C. U.;Lee, Sung-Ik
    • Progress in Superconductivity
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    • v.3 no.1
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    • pp.31-35
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    • 2001
  • We investigated the temperature and magnetic field dependent optical properties of a$ MgB_2$ thin film in the far-infrared region. In the superconducting state, i.e. 5 K, we obtained the values of superconducting gap $2\Delta$ ~ 5.2 meV and $2\Delta$ $_{k}$ $B/T_{c}$ ~1.8. Although the value of$ 2\Delta$$B/T_{c}$ was nearly half of the BCS value, the $2\Delta$ seemed to follow the temperature dependence of the BCS formula. Under the magnetic field (H), the superconducting state became suppressed. Interestingly, we found that the normal state area fraction abruptly increased at low field but slowly increased at high field. It did not follow the H-dependences predicted for a s-wave superconductor (i.e. a linear dependence) nor for a s-wave one (i.e. $H^{1}$2/ dependence). We discussed the complex gap nature of $MgB_2$ in comparison with two gap and anisotropic s-wave scenarios.ios.

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Fabrication and characteristics of 2-Dimensional SSIMT using a CMOS Process (CMOS 공정에 의한 2차원 SSIMT의 제작 및 특성)

  • Song, Youn-Gui;Lee, Ji-Hyun;Choi, Young-Shig;Kim, Nam-Ho;Ryu, Ji-Goo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.443-446
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    • 2003
  • A 2-Dimensional SSIMT(Suppressed Sidewall Injection Magnetotransistor) sensor with high linearity is presented in this paper. The prototype is fabricated by using the Hynix $0.6{\mu}m$ CMOS Process. The fabricated SSIMT shows that the variation of each collectors current are extremely linear by varing the magnetic induction from -200mT to 200mT at $I_B\;:\;1000{\mu}A,\;V_{CE}\;=\;5V\;and\;V_{SUB}\;=\;5V$. The relative sensitivity is up to 13%/T. At B = 0, magnetic offset is about 40mT, there relative sensitivity is 4.72%/T. The nonlinearity of the fabricated 2-D SSIMT is measured about 1.2%.

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Visual Block Coding Tool for Artificial Intelligence IoT Physical Computing Practice (인공지능 IoT 피지컬 컴퓨팅 실습을 위한 비주얼 블록 코딩 도구)

  • Lee, Se-Hoon;Kim, Su-Min;Kim, Young-Ho
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2022.07a
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    • pp.407-408
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    • 2022
  • 본 논문에서는 AIoT를 위한 비주얼 블록 코딩 도구를 설계하였다. AI 블록 코딩이 가능한 EduB 플랫폼에 피지컬 컴퓨팅을 가능하게 하는 모듈을 추가함으로써 블록을 사용한 쉬운 피지컬컴퓨팅 코딩과 AIoT 코딩이 가능하다. 도구는 WebSocket과 Wifi를 사용해 EduB와 타겟보드인 RaspberryPi의 무선 통신을 하며, 블록으로 생성된 코드를 RaspberryPi 내부에서 실행하여 GPIO와 SenseHAT을 제어할 수 있게 하였다. 따라서, 코딩 결과를 콘솔 출력이나 그래프로만 확인할 수 있어 정적이던 AI 교육을 LED나 모터를 제어해 동적으로 결과를 확인할 수 있게 하여 흥미와 관심을 유발할 수 있도록 한다.

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Optical fiber Y-Branch Fabrication and OTDR application (Optical Fiber Y-Branch의 제작과 OTDR 응용)

  • Lee, Sang-Ho;Gang, Min-Ho;Park, Han-Gyu
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.18 no.3
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    • pp.21-24
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    • 1981
  • A simple optial fiber Y-branch is fabricated using micro - torch and fusion splicer. Tapered end of two fibers - in -contact is spliced with another fiber. Total insertion loss is 26dB and optical power branchi ng ratio is 0.98. Using fiber Y-branch, an UTDR with simple optical system is realized The resolution of the OTDR is $\pm$ 5m in length and t 0.5 dB/km in loss coefficient.

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MULTIPLE Lp ANALYTIC GENERALIZED FOURIER-FEYNMAN TRANSFORM ON A FRESNEL TYPE CLASS

  • Chang, Seung Jun;Lee, Il Yong
    • Journal of the Chungcheong Mathematical Society
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    • v.19 no.1
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    • pp.79-99
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    • 2006
  • In this paper, we define a class of functional defined on a very general function space $C_{a,b}[0,T]$ like a Fresnel class of an abstract Wiener space. We then define the multiple $L_p$ analytic generalized Fourier-Feynman transform and the generalized convolution product of functionals on function space $C_{a,b}[0,T]$. Finally, we establish some relationships between the multiple $L_p$ analytic generalized Fourier-Feynman transform and the generalized convolution product for functionals in $\mathcal{F}(C_{a,b}[0,T])$.

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Derivation of A,B,C,D Parameters of Long Transmission Line Using T-model and Hyperbolic Function (T-모델과 쌍곡선함수를 이용한 장거리 송전선로의 A,B,C,D 파라미터 유도)

  • Kim, Do-Won;Lee, Sang-Joong;Yang, Seong-Deog
    • Proceedings of the KIEE Conference
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    • 2008.11a
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    • pp.53-55
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    • 2008
  • 본 논문에서는, 기존의 문헌에 사용되어 온 $\Gamma$형을 대체할 수 있는 새로운 T형 장거리 송전선로 모델을 제시한다. 특히, T-모델은 선로 양단의 병렬 어드미턴스와의 중복이 없다. 또한, 기존 문헌에 제시된 hyperbolic solution을 이용한 간단한 장거리 송전선로 A,B,C,D 파라미터 유도방법을 소개한다. hyperbolic solution으로 장거리 송전선로 파라미터를 유도할 경우, exponential solution보다 수식의 양을 줄일 수 있고, 초기값도 간단하게 구할 수 있다.

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GENERALIZED ANALYTIC FOURIER-FEYNMAN TRANSFORMS AND CONVOLUTIONS ON A FRESNEL TYPE CLASS

  • Chang, Seung-Jun;Lee, Il-Yong
    • Bulletin of the Korean Mathematical Society
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    • v.48 no.2
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    • pp.223-245
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    • 2011
  • In this paper, we de ne an $L_p$ analytic generalized Fourier Feynman transform and a convolution product of functionals in a Ba-nach algebra $\cal{F}$($C_{a,b}$[0, T]) which is called the Fresnel type class, and in more general class $\cal{F}_{A_1;A_2}$ of functionals de ned on general functio space $C_{a,b}$[0, T] rather than on classical Wiener space. Also we obtain some relationships between the $L_p$ analytic generalized Fourier-Feynman transform and convolution product for functionals in $\cal{F}$($C_{a,b}$[0, T]) and in $\cal{F}_{A_1,A_2}$.

Identification of Novel SNPs with Effect on Economic Traits in Uncoupling Protein Gene of Korean Native Chicken

  • Oh, J.D.;Kong, H.S.;Lee, J.H.;Choi, I.S.;Lee, S.J.;Lee, S.G.;Sang, B.D.;Choi, C.H.;Cho, B.W.;Jeon, G.J.;Lee, H.K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.8
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    • pp.1065-1070
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    • 2006
  • The avian uncoupling protein (avUCP) is a member of the mitochondrial transporter superfamily that uncouples proton entry in the mitochondrial matrix from ATP synthesis. The sequencing analysis method was used to identify nucleotide polymorphisms within the avUCP gene in Korean native chicken (KNC). This study identified ten single nucleotide polymorphisms (SNPs) in the avUCP gene. We analyzed the SNPs of the avUCP gene to investigate whether polymorphism in the gene might be responsible for quantitative variations in economic traits in KNC. Three significant polymorphic sites for economic traits were avUCP C+282T (mean body weight, p<0.05), avUCP C+433T (daily percent lay, p<0.05), and avUCP T+1316C (daily percent lay, p<0.05). The frequency of each SNP was 0.125 (C+282T in avUCP gene exon 1 region), 0.150 (C+433T in avUCP gene intron 1 region), and 0.15 (T+1316C in avUCP gene exon 3 region), respectively. Among the identified SNPs, one pair of SNPs (genotype CC, C+282T and TT, avUCP C+433T) showed the highest daily percent lay (p<0.05) and mean body weight (p<0.05) and the frequency was 0.067. This study of the avUCP gene could be useful for genetic studies of this gene and selection on economic traits for KNC.

Prognostic Value of Vascular Endothelial Growth Factor (VEGF) and Basic Fibroblast Growth Factor (bFGF) Expression in Resected Non-small Cell Lung Cancer (수술로 절제된 비소세포폐암 조직에서 예후인자로서 VEGF와 bFGF 발현의 의의)

  • Kim, Seung Joon;Lee, Jung Mi;Kim, Jin Sook;Kang, Ji Young;Lee, Sang Hak;Kim, Seok Chan;Lee, Sook Young;Kim, Chi Hong;Ahn, Joong Hyun;Kwon, Soon Seog;Kim, Young Kyoon;Kim, Kwan Hyoung;Moon, Hwa Sik;Song, Jeong Sup;Park, Sung Hak;Moon, Seok Hwan;Wang, Yeong Pil
    • Tuberculosis and Respiratory Diseases
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    • v.64 no.3
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    • pp.200-205
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    • 2008
  • Background: Tumor angiogenesis plays an important role in tumor growth, maintenance and metastatic potential. Tumor tissue produces many types of angiogenic growth factors. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) have both been implicated to have roles in tumor angiogenesis. In this study, the expression of tissue VEGF and bFGF from non-small cell lung cancer (NSCLC) patients were analyzed. Methods: We retrospectively investigated 35 patients with a histologically confirmed adenocarcinoma or squamous cell carcinoma of the lung, where the primary curative approach was surgery. An ELISA was employed to determine the expression of VEGF and bFGF in extracts prepared from 35 frozen tissue samples taken from the cancer patients. Results: VEGF and bFGF concentrations were significantly increased in lung cancer tissue as compared with control (non-cancerous) tissue. The VEGF concentration was significantly increased in T2 and T3 cancers as compared with T1 cancer. Expression of VEGF was increased in node-positive lung cancer tissue as compared with node-negative lung cancer tissue (p=0.06). VEGF and bFGF expression were not directly related to the stage of lung cancer and patient survival. Conclusion: Expression of VEGF and bFGF were increased in lung cancer tissue, and the expression of VEGF concentration in lung cancer tissue was more likely related with tumor size and the presence of a lymph node metastasis than the expression of bFGF. However, in this study, expression of both VEGF and bFGF in tissue were not associated with patient prognosis.

Effects of the Precipitation of Carbides and Nitrides on the Texture Structures in Extra Low Carbon Steel Sheets containing B, Nb and Ti(ll) (B, Nb및 Ti를 함유한 극저탄소강에서 탄화물 및 질화물의 석출이 집합조직에 미치는 영향(ll))

  • Lee, Jong-Mu;Yun, Guk-Han;Lee, Do-Hyeong
    • Korean Journal of Materials Research
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    • v.3 no.2
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    • pp.131-139
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    • 1993
  • Abstract Alloying elements such as AI, Ti, Nb and B in the extra low carbon AI-killed steel precipitate as nitrides or carbides and change the recrystallization texture structure of the steel during heattreatment with the result of strong effects on the deep drawability of the steel sheet. In this study the effects of fine precipitates such as nitrides and carbides on the texture of extra low carbon steels into which Ti, Nb, B, P, Si and Mn were added as alloying elements were investigated by means of TEM, SEM and optical microscopic analyses. Fine N$b_2$C and T$i_2$AIN precipitates are mainly observed in the steel containing both Nb and Ti, while fine AIN and coarse BN precipitates are observed in the Nb~containing steel and coarse T${i_4}{N_3}$ and ${N_10}{N_22}$/T$i_68$ precipitates are observed in the Ti-containing steel. The grain size of the Ti containing steel is larger than that of the Nb containing steel and that of the one containing both Nb and Ti.

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