• Title/Summary/Keyword: $E_b/N_t$

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Photocurrent Study on the Splitting of the Valence Band and Growth of CuAlSe2 Single Crystal Thin Film by Hot Wall Epitaxy (Hot Wall Epitaxy(HWE)법에 의한 CuAlSe2 단결정 박막의 성장과 가전자대 갈라짐에 대한 광전류 연구)

  • Park, Chang-Sun;Hong, Kwang-Joon;Park, Jin-Sun;Lee, Bong-Ju;Jeong, Jun-Woo;Bang, Jin-Ju;Kim, Hyun
    • Journal of Sensor Science and Technology
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    • v.13 no.2
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    • pp.157-167
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    • 2004
  • A stoichiometric mixture of evaporating materials for $CuAlSe_{2}$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CuAlSe_{2}$ 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 $680^{\circ}C$ and $410^{\circ}C$, 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 $CuAlSe_{2}$ single crystal thin films measured with Hall effect by van der Pauw method are $9.24{\times}10^{16}cm^{-3}$ and $295cm^{2}/V{\codt}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuAlSe_{2}$ obtained from the absorption spectra was well described by the Varshni's relation, $E_{g}(T)$ = 2.8382 eV - ($8.68{\circ}10^{-4}$ eV/K)$T^{2}$/(T + 155 K). The crystal field and the spin-orbit splitting energies for the valence band of the $CuAlSe_{2}$ have been estimated to be 0.2026 eV and 0.2165 eV at 10 K, 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 $CuAlSe_{2}$. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1-}$, $B_{1-}$, and $C_{1-}$ exciton peaks for n = 1.

The Laboratory Study on Estimation of Depositional Properties of Kaolinite Sediments on Saltwater Condition (염도 존재시 고령토 퇴적물의 퇴적특성 산정에 관한 실험적 연구)

  • Hwang, Kyu-Nam;Kim, Nam-Hun;Lee, Yong-Hao
    • Journal of Korea Water Resources Association
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    • v.41 no.9
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    • pp.863-872
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    • 2008
  • In this study, a series of deposition tests have been conducted on saltwater condition(salinity 32 %o) using an annular flume, in order to estimate depositional properties of kaolinite sediments and to analyze the effect of the initial concentration on them. Total 37 deposition tests have been carried out in three different initial concentrations (1000, 5000, 15000 ppm) with varying the bed shear stress. From these test results, minimum shear stress (or critical shear stress for deposition; ${\tau}_{bmin}$) and the deposition rate parameters (${\sigma}_1,\;({\tau}^*_b-1)_{50},\;{\sigma}_2,\;t_{50}$) for kaolinite sediments have been quantified, and the effects of the initial concentration and salinity on depositional properties of cohesive sediments have been analyzed qualitatively. As the results, ${\tau}_{bmin},\;{\sigma}_1\;and\;({\tau}^*_b-1)_{50}$ are found to be 0.147, 0.74 and $0.65N/m^2$ respectively. Through comparing with results from previous studies, the performance of this study and tests results are shown to be good enough to verify.

Quantification of myocardial blood low using dynamic N-13 ammonia PET and actor analysis (N-13 암모니아 PET 동적영상과 요소분석을 이용한 심근 혈류량 정량화 방법 개발)

  • Kim, J.Y.;Choi, Y.;Im, K.C.;Choe, Y.S.;Lee, K.H.;Kim, S.E.;Kim, Y.J.;Kim, B.T.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.11
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    • pp.575-578
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    • 1997
  • Myocardial blood low (MBF) in human can be noninvasively quantified using dynamic N-13 ammonia PET and two-compartment tracer kinetic model. In this study, factor analysis was used to extract the "pure" blood-pool time-activity curves (TACs) and to generate actor images. ive human N-13 ammonia PET dynamic studies were obtained. Three actors and their corresponding actor images were extracted rom each study. The accuracy of MBF estimated by the actor analysis (FA/FA MBF) was examined by comparing to the values estimated using the conventional ROI method (ROI/ROI MBF). MBF obtained by the actor analysis linearly correlated with MBF obtained by the ROI method (slope=0.98, r=0.91). Input unctions obtained by the two methods agreed well. In conclusion, MBF can be measured accurately and noninvasively with dynamic N-13 ammonia PET imaging and actor analysis. This method is simple and acurate and can measure MBF without blood sampling, ROI drawing nor spillover correction.

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UNDERWATER DISTRIBUTION OF VESSEL NOISE (선박소음의 수중분포에 관한 연구)

  • PARK Jung Hee
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.10 no.4
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    • pp.227-235
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    • 1977
  • The noise pressure scattered underwater on account of the engine revolution of a pole and liner, Kwan-Ak-San(G. T. 234.96), was measured at the locations of Lat. $34^{\circ}47'N$, Long. $128^{\circ}53'E$ on the 16th of August 1976 and Lat. $34^{\circ}27'N$, Long. $128^{\circ}23'E$ on the 28th of July, 1977. The noise pressure passed through each observation point (Nos. 1 to 5), which was established at every 10m distance at circumference of outside hull was recorded when the vessel was cruising and drifted. In case of drifting, the revolution of engine was fixed at 600 r. p. m. and the noise was recorded at every 10 m distance apart from observation point No. 3 in both horizontal and vertical directions with $90^{\circ}$ toward the stern-bow line. In case of cruising, the engine was kept in a full speed at 700 r.p.m. and the sounds passed through underwater in 1 m depth were also recorded while the vessel moved back and forth. The noise pressure was analyzed with sound level meter (Bruel & Kjar 2205, measuring range 37-140 dB) at the anechoic chamber in the Institute of Marine Science, National Fisheries University of Busan. The frequency and sound waves of the noise were analyzed in the Laboratory of Navigation Instrument. From the results, the noise pressure was closely related to the engine revolution shelving that the noise pressure marked 100 dB when .400 r. p. m. and increase of 100 r. p. m. resulted in 1 dB increase in noise pressure and the maximum appeared at 600 r. p. m. (Fig.5). When the engine revolution was fixed at 700 r. p. m., the noise pressures passed through each observation point (Nos. 1 to 5) placed at circumference of out side hull were 75,78,76,74 and 68 dB, the highest at No.2, in case of keeping under way while 75,76,77,70 and 67 dB, the highest at No.3 in case of drifting respectively (Fig.5). When the vessel plyed 1,400 m distance at 700 r.p.m., the noise pressure were 67 dB at the point 0 m, 64 dB at 600m and 56 dB at 1,400m on forward while 72 at 0 m, 66 at 600 m and 57 dB at 1,400 m on backward respectively indicating the Doppler effects 5 dB at 0 m and 3 dB at 200 m(Fig.6). The noise pressures passed through the points apart 1,10,20,30,40 and 50 m depth underwater from the observation point No.7 (horizontal distance 20 m from the point No.3) were 68,75,62,59,55 and 51 dB respectively as the vessel was being drifted maintaining the engine revolution at 600 r. p. m. (Fig. 8-B) whereas the noise pressures at the observation points Nos.6,7,8,9 and 10 of 10 m depth underwater were 64,75,55,58,58 and 52 dB respectively(Fig.8-A).

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DNA Structural Perturbation Induced by the CPI-Derived DNA Interstrand Cross-linker : Molecular Mechanisms for the Sequence Specific Recognition

  • Park, Hyun-Ju
    • Archives of Pharmacal Research
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    • v.24 no.5
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    • pp.455-465
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    • 2001
  • The highly potent cytotoxic DNA-DNA cross-linker consists of two cyclopropa[c]pyrrolo[3,4-3]indol-4(5H)-ones insoles [(+)-CPI-I] joined by a bisamido pyrrole (abbreviated to "Pyrrole"). The Pyrrole is a synthetic analog of Bizelesin, which is currently in phase II clinical trials due to its excellent in vivo antitumor activity. The Pyrrole has 10 times more potent cytotoxicity than Bizelesin and mostly form DNA-DNA interstrand cross-links through the N3 of adenines spaced 7 bp apart. The Pyrrole requires a centrally positioned GC base pair for high cross-linking reactivity (i.e., $5^1$-T$AT_2$A*-$3^1$), while Bizelesin prefers purely AT-rich sequences (i.e., $5^1$-T$AT_4$A*-$3^1$, where /(equation omitted) represents the cross-strand adenine alkylation and A* represents an adenine alkylation) (Park et al., 1996). In this study, the high-field $^1$H-NMR and rMD studies are conducted on the 1 1-mer DNA duplex adduct of the Pyrrole where the 5′(equation omitted)TAGTTA*-3′sequence is cross-linked by the drug. A severe structural perturbation is observed in the intervening sequences of cross-linking site, while a normal B-DNA structure is maintained in the region next to the drug-modified adenines. Based upon these observations, we propose that the interplay between the bisamido pyrrole unit of the drug and central C/C base pair (hydrogen-bonding interactions) is involved in the process of cross-linking reaction, and sequence specificity is the outcome of those interactions. This study suggests a mechanism for the sequence specific cross-linking reaction of the Pyrrole, and provides a further insight to develop new DNA sequence selective and distortive cross-linking agents.

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Anti-metastatic Effect of Taraxacum Officinale Water and Ethanol Extracts Through the Regulation of Epithelial-Mesenchymal Transition in Huh7 Cells (Huh7 간암세포에서 민들레 추출물의 상피간엽전환 억제를 통한 항전이 효과)

  • Hyun-Seo Yoon;Hyun An;Chung-Mu Park
    • Journal of The Korean Society of Integrative Medicine
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    • v.11 no.3
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    • pp.59-67
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    • 2023
  • Purpose : Epithelial-to-mesenchymal transition (EMT) is recognized as an important cellular response in metastatic proceduresand characterized by loss of cellular polarity as well as gain of mesenchymal features, which enables migration and invasion. Hepatocellular carcinoma (HCC) is one of the most common primary carcinomas in the liver and exhibits a poor prognosis due to frequent extrahepatic metastasis. Taraxacum officinale has been used for a long time in oriental medicine because of its various pharmacological activitiessuch as anti-rheumatic, anti-inflammatory, antioxidative, and anticarcinogenic activities. In this study, the anti-metastatic activity of T. officinale water extract (TOWE) and ethanol extract (TOEE) was investigated through the regulation of EMT in the Huh7 cells. Methods : The effects of TOWE and TOEE on migratory and invasive activities were investigated by wound healing and in vitro invasion assays. Western blot analysis was also applied to analyze protein expression levels associated with EMT and their upstream transcription factors in Huh7 cells. Results : TOWE and TOEE treatment potently inhibited migration and invasion of Huh7 cells compared to the untreated group. Both extracts treatment inhibited protein expression levels of N-cadherin, matrix metalloproteinase (MMP)-9, and vimentin while E-cadherin was significantly accelerated. In addition, the activated status of transcription factors, Snail, nuclear factor (NF)-κ B, and zinc finger E-box binding homeobox (ZEB)1 was also inhibited with statistical significance. In comparison to both extracts, TOEE more potently attenuated migration, invasion, and EMT markers as well as their transcription factors in Huh7 cells than TOWE, which means that TOEE might possess more functional phytochemicals than TOWE. Conclusion : Consequently, TOWE and TOEEattenuated metastatic activity of hepatocellular carcinoma through the regulation of EMT markers and their transcription factors in Huh7 cells, which means that T. officinale might be a promising strategy for a chemopreventive agent against HCC metastasis.

Transport of space charge between sub-pixels in AC-plasma cell discharge

  • Lee, S.B.;Park, E.Y.;Han, Y.G.;Moon, M.W.;Oh, P.Y.;Song, K.B.;Lee, H.J.;Son, C.G.;Jeong, S.H.;Yoo, N.L.;Hong, Y.J.;Jeong, S.J.;Kim, J.H.;Park, S.O.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.929-931
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    • 2006
  • In this experiment, we have investigated that the transported space charge between sub-pixels in AC-plasma cell discharge. The test pulse 30 V, $5{\mu}s$ was applied to the address electrodes of neighbor cells of discharge occurred cells. And we have measured the transported space charge between sub-pixels in accordance with the various last sustain pulse widths t(time gap between the rising edges of sustain and test pulses) of 0.2 to $3{\mu}s$. It was observed that the peak value of transported space charge has been shown to be 21.5pC at $1.0{\mu}s$. And the IR peak value have been occured after $0.51{\mu}s$ with respect to sustain voltage.

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Citrus Pulp as a Dietary Source of Antioxidants for Lactating Holstein Cows Fed Highly Polyunsaturated Fatty Acid Diets

  • Santos, G.T.;Lima, L.S.;Schogor, A.L.B.;Romero, J.V.;De Marchi, F.E.;Grande, P.A.;Santos, N.W.;Kazama, R.
    • Asian-Australasian Journal of Animal Sciences
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    • v.27 no.8
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    • pp.1104-1113
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    • 2014
  • The effects of feeding pelleted citrus pulp (PCP) as a natural antioxidant source on the performance and milk quality of dairy cows fed highly polyunsaturated fatty acid (FA) diets were evaluated. Four lactating Holstein cows were assigned to a $4{\times}4$ Latinsquare. Treatments, on a dry matter (DM) basis, were i) control diet; ii) 3% soybean oil; iii) 3% soybean oil and 9% PCP and; iv) 3% soybean oil and 18% PCP. When cows fed on citrus pulp, the DM intake tended to decrease. The total tract apparent digestibility of DM and ether extract decreased when cows fed on the control diet compared to other diets. Cows fed PCP had higher polyphenols and flavonoids content and higher total ferric reducing antioxidant power (FRAP) in milk compared to those fed no pelleted citrus pulp. Cows fed 18% PCP showed higher monounsaturated FA and lower saturated FA in milk fat compared with cows fed the other diets. The lowest n-6 FA proportion was in milk fat from cows fed control. The present study suggests that pelleted citrus pulp added to 9% to 18% DM increases total polyphenols and flavonoids concentration, and the FRAP in milk.

Zweitsprachenerwerb und Fremdsprachenlernen - Zur Entwicklung der lernerangemessenen Lern- und Lehrmethode - (제2 언어습득과 외국어 학습 - 상황과 조건에 알맞은 교수법 개발을 위하여)

  • Min Hyanggi
    • Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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    • v.5
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    • pp.375-398
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    • 2002
  • Um von der 'kritischen' Situation des Faches DaF rauszukommen, werden viele Versuche untemommen, durch die Verbesserung des Untenichts in der Richtung nach der Entwicklung der kommunikativen $F\"{a}higkeit$ Deutsch als Fremdsprache wieder attraktiv und $konkurrenzf\"{a}hig$ zu machen. Aber leider sieht die Zwischenbilanz nicht so erfolgreich aus. Eine der Ursachen $daf\"{u}r\;l\"{a}sst$ sich mE. darin sehen, dass die $Ans\"{a}tze,\;die\;haupts\"{a}chlich\;f\"{u}r$ den Unterricht von Deutsch als Zweitsprache entwickelt wurden, ohne $gen\"{u}gende$ Berucksichtigung auf die kulturellen und institutionellen Unterschiede zwischen den Lemsituationen im zielsprachigen Land und im Heimatland der Schuler eingesetzt werden. In diesem Kontext $w\"{a}re\;es\;n\"{o}tig$, auf die Unterschiede zwischen DaF und DaZ und ihre Wirkung auf die Lehrstrategien im DaF-Unterricht zuruckzugreifen, Dabei sind auf einige Faktoren besonders zu achten, die DaF-Untenicht vom DaZ-Untenicht unterscheiden: die Mangel an den $M\"{o}glichkeiten$ der authentischen Kommunikation, die $Homogenit\"{a}t\;der\;Sch\"{u}ler$, die Lemkultur in der schlulischen Institution, das Alter, in dem die Sch\"{u}ler$ mit dem Lemen der Zielsprache beginnen. Daraus lassen sich die folgenden unterrichtlichen Konsequenzen ergeben: Die Lehrer sollten sich bemtihen, den $Sch\"{u}lern\;die\;M\"{o}glichkeiten\;f\"{u}r$ die authentischen Kommunikation besorgen, besonders $au{\ss}erhaib$ des Unterrichts, z.B. durch das Chatting- Projekt, $w\"{a}hrend$ im Unterricht mehr $Anl\"{a}sse\;f\"{u}r$ die Reflexion gegeben sollten. Und dabei sollten die unterrichtlichen Vorteile-die gemeinsame Muttersprache und Kultur, das Alter usw. - aktiv benutzt werden. Die meisten Koreaner beginnen $n\"{a}mlich$ mit dem Lernen der zweiten Fremdsprache erst in oder nach der $Pubert\"{a}t$. In diesem Zusammenhang sollte es auch betont werden, dass sich die Autonomie der Lerner durch den Unterricht richtig entwickelt, damit sie $sp\"{a}ter$ ihre Fertigkeiten autonom entwickeln $k\"{o}nnen$.

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Characteristics of Metachronous Remnant Gastric Cancer After Proximal Gastrectomy: A Retrospective Analysis

  • Kenichi Ishizu;Tsutomu Hayashi;Rei Ogawa;Masashi Nishino;Ryota Sakon;Takeyuki Wada;Sho Otsuki;Yukinori Yamagata ;Hitoshi Katai;Yoshiyuki Matsui;Takaki Yoshikawa
    • Journal of Gastric Cancer
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    • v.24 no.3
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    • pp.280-290
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    • 2024
  • Purpose: Despite annual endoscopy, patients with metachronous remnant gastric cancer (MRGC) following proximal gastrectomy (PG) are at times ineligible for endoscopic resection (ER). This study aimed to clarify the clinical risk factors for ER inapplicability. Materials and Methods: We reviewed the records of 203 patients who underwent PG for cT1 gastric cancer between 2006 and 2015. The remnant stomach was categorized as a pseudofornix, corpus, or antrum. Results: Thirty-two MRGCs were identified in the 29 patients. Twenty MRGCs were classified as ER (ER group, 62.5%), whereas 12 were not (non-ER group, 37.5%). MRGCs were located in the pseudo-fornix in 1, corpus in 5, and antrum in 14 in the ER group, and in the pseudofornix in 6, corpus in 4, and antrum in 2 in the non-ER group (P=0.019). Multivariate analysis revealed that the pseudo-fornix was an independent risk factor for non-ER (P=0.014). In the non-ER group, MRGCs at the pseudo-fornix (n=6) had more frequent undifferentiated-type histology (4/6 vs. 0/6), deeper (≥pT1b2; 6/6 vs. 2/6) and nodal metastasis (3/6 vs. 0/6) than non-pseudo-fornix lesions (n=6). We examined the visibility of the region developing MRGC on an annual follow-up endoscopy one year before MRGC detection. In seven lesions at the pseudofornix, visibility was only secured in two (28.6%) because of food residues. Of the 25 lesions in the non-pseudo-fornix, visibility was secured in 21 lesions (84%; P=0.010). Conclusions: Endoscopic visibility increases the chances of ER applicability. Special preparation is required to ensure the complete clearance of food residues in the pseudo-fornix.