• Korean Journal of Optics and Photonics
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• v.23 no.3
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• pp.103-107
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• 2012

We investigate the dependence of the output of a mode locked Yb-doped fiber laser on incident intra-cavity intensity on a semiconductor saturable absorber mirror (SESAM). To vary the incident intra-cavity intensity, we change the beam spot size on a SESAM by varying the focal length of a lens installed in the front of the SESAM.

• Korean Journal of Optics and Photonics
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• v.11 no.5
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• pp.340-346
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• 2000

Traveling wave type semiconductor optical amplifiers integrated with spot-size-converter (SSC-TW-SOA) have been extensively studied for the improvement of coupling effiClency With single-mode fiber and fO! the cost reducClon 111 a packaging In tlIis paper the slructural dependence of the spot-slZe-converter on the effective facet reflectlvllY $R_{eff}$ was experimentally as well as thcoretienlly mvestlgated. It was shown that not only a sufficient mode-conversion in a sse region along the latersl and tran~verse directions but also an introductIOn of angled-facet were very essential in order to reduce $R_{eff}$ Very small ripple less than 0.1 dB in an amplified spontaneous emission spectrum was observed with the fabncated SSC-lW-SOA which consists of the wrndow length of $20\mu\textrm{m}$, facet angle of $7^{\circ}$, and antlrelleetioll-coated facet of ] % reflectivity.tivity.

• Journal of the Korean Ceramic Society
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• v.53 no.5
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• pp.511-520
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• 2016

Electrolyte-supported symmetric Ni-YSZ cermet electrodes of ca. $23{\mu}m$ were prepared by screenprinting and the impedance was measured as a function of humidity from 2% to 90% balanced in $H_2$ at a total flow rate of 50 sccm. The Ni felt current collector of 1 mm thickness exhibited a Gerischer-like gas concentration impedance in the low frequency range, which was similarly observed in the cermet-supported solid oxide cells, while the Pt paste collector exhibited only electrochemical polarization. The electrochemical polarization of both samples was modeled by a non-ideal diffusion-reaction transmission line model including CPEs with ${\alpha}$= 0.5. In the case of the Pt paste collector, all the Bisquert parameters exhibited humidity dependence to the -1/2 power, supporting a non-faradaic chemical reaction mechanism at three phase boundaries. Consequently, the surface diffusivity and reaction rate increased linearly with humidity. Less pronounced humidity dependence and somewhat lower utilization length with an Ni felt collector can be attributed to the diffusion-limited gas flow through the collector.

• Journal of Distribution Science
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• v.20 no.5
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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.

• Journal of the Korean Ceramic Society
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• v.55 no.3
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• pp.244-260
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• 2018

Issues in the electrical characterization of semiconducting photoanodes in a photoelectrochemical (PEC) cell, such as the cell geometry dependence, scan rate dependence in DC measurements, and the frequency dependence in AC measurements, are addressed, using the example of a $TiO_2$ photoanode. Contrary to conventional constant phase element (CPE) modeling, the capacitive behavior associated with Mott-Schottky (MS) response was successfully modeled by a Havriliak-Negami (HN) capacitance function-which allowed the determination of frequency-independent Schottky capacitance parameters to be explained by a trapping mechanism. Additional polarization can be successfully described by the parallel connection of a Bisquert transmission line (TL) model for the diffusion-recombination process in the nanostructured $TiO_2$ electrode. Instead of shunt CPEs generally employed for the non-ideal TL feature, TL models with ideal shunt capacitors can describe the experimental data in the presence of an infinite-length Warburg element as internal interfacial impedance - a characteristic suggested to be a generic feature of many electrochemical cells. Fully parametrized impedance spectra finally allow in-depth physicochemical interpretations.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.12
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• pp.1-8
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• 2005

The gate length-dependence of cutoff frequency is modeled by using scaling parameter equations of equivalent circuit parameters extracted from measured S-parameters of Nano-scale MOSFETs. It is observed that the modeled cutoff frequency initially increases with decreasing gate length and then the rate of increase becomes degraded at further scale-down. This is because the extrinsic charging time slightly decreases, although the intrinsic transit time greatly decreases with gate length reduction. The new gate length-dependent model will be very helpful to optimize RF performances of Nano-scale MOSFETs.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.475-482
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• 2007

The thermal and optical properties of glucose penta(cholesteryloxycarbonyl)alkanoates (CAGLn, n = 2~8, 10, the number of methylene units in the spacer) were investigated. All the CAGLn formed monotropic cholesteric phases with left-handed helical structures. CAGLn with n = 2 or 10, in contrast with CAGLn with $3{\leq}n{\leq}8$, did not display reflection colors over the full cholesteric range, suggesting that the helical twisting power of the cholesteryl group highly depends on the length of the spacer joining the cholesteryl group to the glucose chain. The isotropic-cholesteric transition point ($T_{ic}$) decreased with increasing n and showed no odd-even effect. The plot of transition entropy at $T_{ic}$ against n had a sharp negative inflection at n = 7. The optical pitches (${{\lambda}_m}^{\prime}$ s) of CAGLn with $3{\leq}n{\leq}8$ decreased with increasing temperature. However, the temperature dependence of the ${\lambda}_m$ of the derivatives exhibited pronounced dependence on n. The transitional properties and the temperature dependence of the ${\lambda}_m$ observed for CAGLn were discussed in terms of the differences in arrangement of the cholesteryl groups and the conformation of the molecules.

• The Korean Journal of Physiology
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• v.14 no.2
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• pp.7-16
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• 1980

The effects of various inotropic interventions on the shape of the steady state length tension relation and the length-dependent activation process in cardiac muscle were studied. The influence of inotropic interventions upon the action potential was also observed. The range of varying muscle length was from the optimal length$(l_{max})$, where the active tension production is maximal, to 0.85 $l_{max}$. Changes in stimulus frequency or in external bathing Ca concentration constituted the inotropic interventions in this experiment. The papillary muscles were isolated from the rabbit right ventricles and perfused with $HCO-_3\;-buffered$ normal Tyrode solution which was aerated with $3%\;CO_2-97%\;O_2$ mixed gas and kept at $35^{\circ}C$. Resting Passive tension at $l_{max}$ was approximately 30% of the total tension and appeared from the muscle length of 0.90 $l_{max}$. The effect of stimulus frequency on the steady state level of developed tension was: As the stimulus frequency was increased from 0.1 to 0.5 Hz, there was little change in developed tension. As the frequency was increased further, to a value of about 3 Hz, tension increased steeply. Further increase of the frequency to 5 Hz had little additional effect on the developed tension. The length-tension curves for isometric peak tension became more steeper with the degree of potentiation by inotropic interventions. The relative steepness of the normalized length-tension curves where tension production was expressed as a percentage of maximal tension developed at $l_{max}$, varied inversely with the level of inotropic state and these curves were not superimposable one another. Thus at the stimulus frequency of 2 Hz or at the external Ca concentration of 8 mM, the relative decline in the developed tension for a given change in muscle length was considerably less than the decline observed at the frequency of 0.5 Hz or at the concentration of 2 mM Ca. Action potential duration was prolonged significantly as the frequency increased from 0.2 to 2 Hz, and this change in action potential duration was not observable on the changes in muscle length. There was a tendency of the hyperpolarization of membrane potential when the muscle length was shortened from $l_{max}$ to 0.95 $l_{max}$. These results support the hypothesis that there is a length-dependence of the activation process.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.3
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• pp.239-248
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• 2003

This paper was conducted as an attempt in order to construct the data bank of target strength for acoustic estimation of fish length in the coastal waters of Korea. The fish length dependence of acoustic target strength for 13 large yellow croakers (Pseudosciaena crocea) at 75 kHz was investigated and the prediction of the target strength by using the Kirchhoff-Ray Mode model (KRM model) was compared with target strength measurements. The results obtained are summarized as follows; 1. In the averaged target strength pattern for 13 large yellow croakers the maximum target strength was -35.13 dB at $-13.35^{\circ}$ on a tilted angle. 2. The relationship between fork length(L, cm) and averaged target strength(TS, dB) was expressed as follows; TS=23. 76log (L) -73.45 (r=0.47) TS=20log(L) -67.35 From this result, the conversion coefficient was -73.45 dB and 6.1 dB lower than the coefficient -67.35 dB where the value of the slope of the regression equation is forced to be 20. 3. Averaged target strength and a length conversion coefficient derived from a target strength histogram for 13 large yellow croakers of mean length 25.59 cm were -41.23 dB, -69.72 dB, respectively. 4. In the range of $$2;{\ll} L (fish length /{\lambda}(wave length);{\ll}40$$, the prediction of the averaged target strength by the KRM model increased gradually with the increasing of $L/{\lambda}$ and was lower than the measured target strength.

• Korean Journal of Biological Psychiatry
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• v.18 no.4
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• pp.260-266
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• 2011

Objectives The second to fourth digit ratio (2D : 4D) is known to reflect testosterone level during intrauterine period. Testosterone is essential for masculinization of brain. Cloninger's type II alcoholism is characterized by early age at onset and largely limited to males. Compared with type I alcoholism, type II alcoholism is thought to be masculine. There is a possibility that the digit ratio of type II alcoholism is low compared with type I. We examined digit length ratio in Cloninger's type I and II alcoholism to understand the effects of intrauterine testosterone on the development of alcoholism. Methods The participants were 87 alcohol dependent patients. We divided two subtypes of patients by Irwin's symptom list, based on Cloninger's concept. We captured the images of both palms by the scanner and measured the lengths of digits by the graphic program. Then we analyzed the digit ratios by independent-sample t-test. Results The mean 2D : 4D of type I was 0.942 (right), 0.952 (left). The mean 2D : 4D of type II was 0.927 (right), 0.940 (left). In both hands, 2D : 4D of type II was significantly lower than type I. Conclusions Type II alcoholism showed masculine type of digit length ratio compared with type I. It suggests the exposure of testosterone during intrauterine period might play an important role in determining the course and feature of alcoholism.