• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.581-590
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• 2001

This paper has been studied about supply of optical source of laser diode with stable and uniform output wavelength in optical transmission system. The stabilized constant current circuit is designed. The temperature control circuit is constructed for the control of internal temperature of laser diode. Also, the wavelength locker is used in optical output. Finally, A/D, D/A converter and micro-processor are used for the control of temperature.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2691-2696
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• 2009

Effects of representative group II and transition metal ions on the stability of the $poly(dA){\cdot}[poly(dT)]_2$ triplex were investigated by the van’t Hoff plot constructed from a thermal melting curve. The transition, $poly(dA){\cdot}[poly(dT)]_2\;{\rightarrow}\;poly(dA){\cdot}poly(dT)\;+\;poly(dT)$, was non-spontaneous with a positive Gibb’s free energy, endothermic (${\Delta}H^{\circ}$ > 0), and had a favorable entropy change (${\Delta}S^{\circ}$ > 0), as seen from the negative slope and positive y-intercept in the van’t Hoff plot. Therefore, the transition is driven by entropy change. The $Mg^{2+}$ ion was the most effective at stabilization of the triplex, with the effect decreasing in the order of $Mg^{2+}\;>\;Ca^{2+}\;>\;Sr^{2+}\;>\;Ba^{2+}$. A similar stabilization effect was found for the duplex to single strand transition: $poly(dA){\cdot}poly(dT)\;+\;poly(dT)\;→\;poly(dA)\;+\;2poly(dT)$, with a larger positive free energy. The transition metal ions, namely $Ni_{2+},\;Cu_{2+},\;and\;Zn_{2+}$, did not exhibit any effect on triplex stabilization, while showing little effect on duplex stabilization. The different effects on triplex stabilization between group II metal ions and the transition metal ions may be attributed to their difference in binding to DNA; transition metals are known to coordinate with DNA components, including phosphate groups, while group II metal ions conceivably bind DNA via electrostatic interactions. The $Cd_{2+}$ ion was an exception, effectively stabilizing the triplex and melting temperature of the third strand dissociation was higher than that observed in the presence of $Mg_{2+}$, even though it is in the same group with $Zn_{2+}$. The detailed behavior of the $Cd_{2+}$ ion is currently under investigation.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.7
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• pp.523-529
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• 2011

This study has been performed to examine the influence of the size of particles on the stabilization in the aerobic stabilization equipment connected with MBT system. The biodegradable waste inside the reactor (60% of food waste, 25% of paper waste, 2% of wood waste and 5% of compost) has been charged in same composition. The degree of stabilization was compared and analyzed after charging with adjustment of particle size in 5 mm, 10 mm, 20 mm, 50 mm, 100 mm and state of no separation. The experiment revealed that highest temperature beyond $65^{\circ}C$ was shown in the particle size of less than 50 mm in change of temperature and the highest temperature was about $50^{\circ}C$ in reactor of 100 mm and no separation. The proportionality between generated quantity of $CO_2$ and particle size was not observed, even the highest in generated quantity was shown in over 100 mm. The weight changes based on wet and dry conditions in the reaction process showed the 30% and 46% of reduction in the smallest particle size of 5 mm and it showed the trend of the lower reduction rate at the bigger particle size. The water soluble $COD_{Cr}$ and TOC showed the reduction rate of 60% in reactor of particle size in 100 mm and no separation while the reduction rate comparing to the initial stage of reaction in the reactor of less than 50 mm was 80%. Such result derived the conclusion of acceleration in the decomposing stabilization of biodegradable material due to the decomposing rate of organic substance as the particle size of biodegradable waste gets smaller. It is concluded as necessary to react in adjustment under 50 mm of particle size as much as possible.

• Journal of the Korean Electrochemical Society
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• v.4 no.3
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• pp.104-108
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• 2001

Naphthalene derived mesophase pitch WP) was spun into short fibers by using melt-blown technology. The pitch fibers oxidative stabilization were carried out heating rates of $2^{\circ}C/min,\;5^{\circ}C/min\;and\; 10^{\circ}/min$. The heating rate was a key factor to maximate the capacity of the Li-ion secondary battery through controlling the morphology of the graphitized fiber. The diameters of the melt-blown fibers prepared were in the range of $4{\mu}m\~16{\mu}m$ with functions of air jet speed, air temperature and the temperature of the nozzle. The graphitized fibers of $10{\mu}m$ diameters showed various morphological structure with heating rate of the stabilization. Radial, radial-random and skin-core cross-sectional structure of the fibers were observed at the respective heating rate of $2^{\circ}C/min\;5^{\circ}C/min\;and\;10^{\circ}C/min$. Most crystalline structure of graphite was obtained from the fiber stabilized at heating rate of $10^{\circ}C/min$ exhibiting the best anode performance with 400 mAh/g of capacitance and $96.8\%$ of charge/discharge efficiency.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.4
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• pp.69-79
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• 1992

To estimate soil behavior and structural characteristics under the conditions of cyclic loading, freezing & thawing and initial state, several testing was performed and obtained following results. 1.After repeated freezing and thawing processes, original soil structure was destroyed and changed to globular structure from honeycomb or tube in its structure types. Also above processes resulted increasing the soil compression strain while decreasing the failure stress in stress-strain relationship and reached the soil structure into the mode of brittle fracture. Under cyclic loading conditions, soil cluster which was originally dispersed structure colloided with each other, seperated, and finally the soil failed due to the effect of overcompaction. 2.Through the stabilization processes seperated by four steps, the structure of soil skeleton was changed to quite different globular type. The degree of compressibility of soil was decreased in the normally consolidated zone, while the strength against external load increased due to soil particle stabilization. 3.Soil stress-strain chracteristics were largely influenced by repeated up and down processes of temperature. The maximum deformation was obtained in the case of temperature between 0 10˚C by the reseon of particle cluster reformation. 4.Soil compressibility was largely influenced by the optimum moisture content. Under freezing process, swelling could be found and its magnitude was proportional to the density of soil. 5.Density of soil was decreased as increasing the number or repeated freezing and thawing processes and the largest decreasing rate was found at the first turning point from freezing to thawing cycle.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.121.1-121.1
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• 2010

We analyzed the temperature and chemical composition of 376 hot springs in Korea. It took about three days for the temperature to stabilize after the pumping test. After the stabilization, in-situ and laboratory analyses of the hot spring water were carried out. The average temperature and TDS were $29.95^{\circ}C$ and 2,071mg/L, respectively. The temperature ranging $25-30^{\circ}C$ were recorded from 70% of hot springs, and $30-35^{\circ}C$ of 15.4%. The maximum temperature was about $78^{\circ}C$. The value of TDS in 79% of the wells was below 1,000 mg/L. 5.5% of the wells, mostly developed near seashore, shows higher values than 10,000mg/L of TDS suggesting the influence of seawater. The hot spring water shows 8.49 of pH representing a weak alkali. For the mineral compositions dissolved in the hot spring in Korea, Na (431 mg/L) and Ca (188 mg/L) are the major cations, and Cl (840 mg/L) and $SO_4$ (213 mg/L) are the major anions.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.435-442
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• 2016

For inertial navigation systems, initial information such as position, velocity and attitude is required for navigation. Self-alignment is the process to determine initial attitude on stationary condition using inertial measurements such as accelerations and angular rates. The accuracy of self-alignment is determined by inertial sensor error. As soon as an inertial navigation system is powered on, the temperature of accelerometer rises rapidly until temperature stabilization. It causes acceleration error which is called temperature stabilizing error of accelerometer. Therefore, temperature stabilizing error degrades the alignment accuracy and also increases alignment time. This paper suggests a method to calculate azimuthal attitude using curve fitting of horizontal control angular rate in fixed-gain self-alignment. It is verified by simulation and experiment that the accuracy is improved and the alignment time is reduced using the proposed method under existence of the temperature stabilizing error.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.7-14
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• 2004

The lift-off characteristics of the triple flame have been studied experimentally with various mean velocities and concentration gradients using a multi-slot burner, which can control the concentration gradient and the mean velocity independently, Lift-off height, axial maximum velocity, flame temperature, and some other characteristics were examined for methane and propane flame, It was found that minimum values of the lift-off heights exist at a certain concentration gradient for constant mean velocity, and this result implies that the propagation velocity has a maximum value at this condition, OH radical distribution was measured with LIF method and velocity variation along streamline was measured with PlV system. In addition maximum temperature along streamline was measured with CARS system. The intensity of the diffusion flame affects on the propagation velocity of triple flame in the region of very weak concentration gradient.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.3
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• pp.184-192
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• 1991

In many combustion systems, swirling combustion air is extensively applied as an aid for stabilization of high intensity combustion pocesses. Swirl, generally, causes significant effects on the flow field which, in turn, determines the size, shape, and stability of flames, and combustion intensity. The purpose of this study is to investigate the effect of swirls on flames produced from a model combustor designed in this paper. In order to impart swirls to the combustion air, a movable block swirl generator was used. Temperature distribution and radiative heat flux along the centerline of the swirling flame were measured. Data obtained from these swirl flows can be used as design data for high intensity or high efficiency combustion systems. The results obtained are summarized as follows: 1. Flame temperature profiles were measured at various swirl number. 2. The axial distance for maximum temperature from the centerline of burner increased as the swirl number increased. 3. Radiative heat flux increased as the swirl number and axial distance from burner increased.

• Proceedings of the Botanical Society of Korea Conference
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• 1999.08a
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• pp.68-82
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• 1999

CHilling tolereance of plants are closely correlated with the degree of fatty acid unsaturation of membrane lipids. We studied the effects of low-temperature photoinhibition on the photochemical efficiency of photosystem II in terms of fatty acid unsaturation of thylakoid membranes lipids isolated from chilling -sensitive plants and chilling -resistant ones. To directly test the chilling tolerance of photosynthetic machinery in relation to membrane lipids, we further compared wild type tobacco plants with that of transgenic tobacco plants, in which the sensitivity to chilling had been enhanced by genetic modification of fatty acid unsaturation of chloroplast membrane lipids. The transgenic tobacco plants were found to contain reduced levels of unsaturated membrane fatty acids after being transformed with cDNA for glycerol-3-phophate acyltransferase from squash. The functional integrity of photosystem II during and recovery of photosynthesis from low-temperature photoinhibition will be discussed in connection with the degree of fatty acid unsaturation of chlorophast membranes lipids.