• Bulletin of the Korean Chemical Society
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• 제6권5호
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• pp.321-322
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• 1985

• 한국안광학회지
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• 제7권2호
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• pp.169-174
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• 2002

Photochromic lens의 광감성 평가 방법을 만들고, 이를 적용시키기 위하여 Photochromic lens에 UV light source을 조사하였다. UV light 광원을 조사 전과 후의 darkening과 fading 상태의 transmittance(T%)의 파장 의존성을 spectrophotometer, light source, power meter, detecter로 구성된 광학적 장치로 측정한다. 조사 직전의 최대 $T%{\times}{\lambda}$ 면적과 saturated state면적의 상대적 비율을 이용한다. Photochromic lens에서 조사시간 의존성의 평가는 darkening 효율도 ($K_d$)값 ($(1-C_1/A_1)/t_{on}$과 fading 효율도($K_f$)값 ($(C_2/A_2)/t_{on}$을 도입하였다. Darkening과 fading 상태에서 transmittance(T%)의 파장의존성은 $T_m+T_1{\exp}[-(x_0-t)/a]$의 형태를 갖는다. Photochromic lens에서 광감성의 평가 parameter Z, $K_d$, $K_f$를 적용한 결과 각 평가 지수 값을 얻을 수 있다.

• The Korean Journal of Physiology and Pharmacology
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• 제26권5호
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• pp.397-404
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• 2022

Fesoterodine, an antimuscarinic drug, is widely used to treat overactive bladder syndrome. However, there is little information about its effects on vascular K⁺ channels. In this study, voltage-dependent K⁺ (Kv) channel inhibition by fesoterodine was investigated using the patch-clamp technique in rabbit coronary artery. In whole-cell patches, the addition of fesoterodine to the bath inhibited the Kv currents in a concentration-dependent manner, with an IC₅₀ value of 3.19 ± 0.91 μM and a Hill coefficient of 0.56 ± 0.03. Although the drug did not alter the voltage-dependence of steady-state activation, it shifted the steady-state inactivation curve to a more negative potential, suggesting that fesoterodine affects the voltage-sensor of the Kv channel. Inhibition by fesoterodine was significantly enhanced by repetitive train pulses (1 or 2 Hz). Furthermore, it significantly increased the recovery time constant from inactivation, suggesting that the Kv channel inhibition by fesoterodine is use (state)-dependent. Its inhibitory effect disappeared by pretreatment with a Kv 1.5 inhibitor. However, pretreatment with Kv2.1 or Kv7 inhibitors did not affect the inhibitory effects on Kv channels. Based on these results, we conclude that fesoterodine inhibits vascular Kv channels (mainly the Kv1.5 subtype) in a concentration- and use (state)-dependent manner, independent of muscarinic receptor antagonism.

• 한국진공학회지
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• 제7권s1호
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• pp.20-24
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• 1998

Photploymer films are widely used in printing and electronic industries, and their usage is expanding to encompass holography, data storage and data processing, optical waveguides and compact disks, etc. One of widely used photoplymerization initiator, 20chloro-hexaarylbiimidazole (o-Cl-HABI), is studied by laser flash photolysis in dichloromethane solution in the absence and presence of the visible light photosensitizing dye, 2, 5-bis[(2, 3, 6, 7 -tetrahydro- 1H, 5H -benzo [i, j,] quinolizin -1-yl) methylene]-cyclopenta-none, (JAW). In the presence of JAW, an increase in triarylimidazolyl radicals L.formation is observed in relative to the absence of JAW. The mechanism of this photosensitizing dissociation is concluded as the dissociation of the o-Cl-HABI radical anion formed by the electron transfer from excited singlet state of JAW to o-Cl-HABI. The observed formation of L.radicals exhibits a linear dependence on o-Cl-HABI concentration. The rate constant of electron transfer obtained from this dependence is equal to (1.0$\pm$0.2) x $10^9 M^{-1}s^{-1}$. No reaction between the excited triplet state of JAW and o-Cl-HABI is found.

• The Korean Journal of Ceramics
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• 제4권2호
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• pp.78-82
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• 1998

The oxygen nonstoichiometry (x) of UO$_{2+x}$ and $(Ce_yU_{1-y})O_{2+x}$ (y=0.05, 0.25) has been measured as a function of oxygen activity (a02) at 100$0^{\circ}C$ by a solid state coulometri titration technique. The results for UO$_{2+x}$ are in a good agreement with literature data and the ao2-dependence of the nonstoichimetry has been well explained with (2:2:2) cluster model. The equilibrium oxygen activity of $(Ce_yU_{1-y})O_{2+x}$ increases with Ce-content (y) for given nonstoichiometry (x), which is ascribed to the fact that Ce is present as Ce$^{3+}\; and\; Ce^{4+}$, and, therefore, the addition of Ce reduces the oxidation capacity of UO$_{2+x}$. From the oxygen activity dependence of x in $(Ce_yU_{1-y})O_{2+x}$ the defect structure of $(Ce_yU_{1-y})O_{2+x}$ is discussed.

• Journal of Life Science
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• 제9권2호
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• pp.44-48
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• 1999

The ionization of tyrosine residue is known to be involved in the stabilization of transition-state in catalysis of astacin based upon the astacin-transition state analog structure. Two tyrosine residues, Tyr-216 and Tyr-219, are conserved in all MMPs related with astacin family, We replaced Tyr-216 and Tyr-219 into phenylalanine, respectively and the zinc binding properties, kinetic parameters, and pH dependence of each mutant are determined in order to examine the role of tyrosine residue in matrilysin catalysis. Both mutants contain two zinc atoms per mol of enzyme, indicating that either tyrosime does not affect the zinc binding property of the enzyme. Y216F and Y219F mutants are highly active and the kcat/Km values are only decreased 1.1-1.5-fold compared to the wild-type enzyme. The decrease in the activity of the mutants is essentially due to the increase in Km value. The pH dependencies of the kcat/Km values for both mutants are similar to the corresponding dependencies obtained with the wild type enzyme. The pKa values at the alkaline side of both mutants are not changed. These kinetic and pH dependence results indicate that the ionization of active site tyrosine residue of matrilysin is not reflected in the kinetics of peptide hydrolysin as catalyzed by astacin.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.172-172
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• 1999

Perovskite Manganese Oxide has been intensively investigated since the discovery of the colossal magnetoresistive(CMR) effect. In this paper, we studied the effect of temperature dependence and various doping dependence of rare earth site ions of La0.7-xPrxCa0.3MnO3 series using Ultraviolet Photoelectron spectroscopy(UPS). They show unusual temperature dependent features and the doped rare earth ions seem to affect the electron-phonon coupling strongly. We found clear evidence of metal-insulator transition from the spectral density at the Fermi level. but the transition temperature is lower than that deduced from transport measurements. Also we found that the spectral features change as time goes on implying that the surface of these materials is somewhat unstable in the vacuum. We can conclude from these results that the surface oxygen atoms correlated to the hopping electrons can escape from the material into the vacuum and that the surface state of these material is different from the bulk state.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.123-124
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• 2007

A silver indium sulfide ($AgInS_2$) epilayer was grown by the hot wall epitaxy method, which has not been reported in the liteniture. The grown $AgInS_2$ epilayer has found to be a chalcopyrite structure and evaluated to be high quality crystal. From the photocurrent measurement in the temperature range from 30 K to 300 K, the two peaks of A and B were only observed, whereas the three peaks of A, B, and C were seen in the PC spectrum of 10 K. These peaks are ascribed to the band-to-band transition. The valence band splitting of $AgInS_2$ was investigated by means of the photocurrent measurement. The temperature dependence of the energy band gap of the $AgInS_2$ obtained from the photocurrent spectrum was well described by the Varshni's relation, $E_g(T)=\;E_g(0)\;eV-(7.78\;{\times}\;10^{-4}\;eV/K)T^2/(T\;+\;116\;K\;K)$. Also, Eg(0) is the energy band gap at 0 K, which is estimated to be 2.036 eV at the valence band state A and 2.186 eV at the valence band state B.

• Applied Science and Convergence Technology
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• 제27권5호
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• pp.109-112
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• 2018

Optical properties of InAs/GaAs submonolayer-quantum dot (SML-QD) have been investigated using excitation intensity ($I_{ex}$)- and temperature-dependent photoluminescence (PL). At a low temperature (13 K) strong PL was observed at 1.420 eV with a very narrow full-width at half maximum, of 7.09 meV. The results of the $I_{ex}$ dependence show that the PL intensities increase with increasing $I_{ex}$. The enhancement factors (k) of PL increment as a function of $I_{ex}$ are 3.3 and 1.22 at low and high $I_{ex}$ regime, respectively. The high k value at low $I_{ex}$, implies that the activation energy of the SML-QDs is low. The calculated activation energy of the SML-QDs from temperature dependence is 30 meV.

• 유통과학연구
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• 제20권5호
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• pp.23-33
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• 2022

Purpose: The purpose of this article is to study the theory of railway transport in Azerbaijan. And also to determine the economic importance of this mode of transport and analyze its relationship with the country's GDP. Research design, data and methodology: This paper studies the theory of railway transport with a focus on the case of Azerbaijan. The economic value of this type of transport is determined, and its relationship with countries' GDP was analyzed. A qualitative model of multiple regressions was developed to characterize the dependence of the GDP of Azerbaijan on the performance of the railway industry. The feasibility of the Gauss-Markov hypotheses was analyzed. Finally, an economic interpretation of the results from the developed model is provided. Results: The results show that the main factors of this dependence are the length of roads and the average monthly salary of employees of the railway industry in Azerbaijan. Conclusions: Therefore, it can be concluded that rail transport contributes to the country's economy. The commencement of active work on the new railway Baku-Tbilisi-Kars railway will increase contribution to the economy of Azerbaijan. The development of railway transportation is important for the country's economy, as it will contribute to the development of other sectors in Azerbaijan.