• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.319-322
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• 2002

In this Paper, we suggested the Half-Bridge inverter for the automotive HID electronic ballast. electronic ballast for automotive HID lamp should be supplied by low-frequency square wave avoiding the acoustic resonance(11kHz ∼ 825kHz). When the HID lamp is hot state, the electronic ballast should supply the sufficient current for a few milli-second to the lamp at the re-strike ignition state. that is called take-over current. We have introduced the new take-over current control method that could have reduced the peak current and supplied the sufficient take-over current.

• Journal of Korea Water Resources Association
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• v.44 no.5
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• pp.377-388
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• 2011

Surface Image Velocimetry (SIV) is a recently-developed discharge measurement instrument. It uses image processing techniques to measure the water surface velocity and estimate water discharge with given cross section. The present study aims to implement a FSIV (Fixed-type Surface Image Velocimetry) at Soojeon Bridge in the Dalcheon. The hardware system consists of two digital cameras, a computer, and a pressure-type water stage gauge. The images taken with the hardware system are sent to a server computer via a wireless internet, and analyzed with a image processing software (SIV software). The estimated discharges were compared with the observed discharges through Goesan dam spillway and index velocity method using ADVM. The computed results showed a good agreement with the observed one, except for the night time. The results compared with discharges through Goesan dam spillway reached around 5~10% in the case of discharge over 30 m3/s, and the results compared with discharges through index velocity method using ADVM reached around 5% in the case of discharge over 200 $m^3/s$. Considering the low cost of the system and the visual inspection of the site situation with the images, the SIV would be fairly good way to measure water discharge in real time.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.89-95
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• 2019

Mooring observations of water temperature and salinity were conducted to investigate the effects of freshwater discharge patterns on the mouth of Nakdong River from April 2017 to March 2018. More than $500-1000m^3\;s^{-1}\;d^{-1}$ of freshwater was frequently discharged into the estuary throughout the rainy season, but less than $200m^3\;s^{-1}\;d^{-1}$ was discharged through the normal season. Sluice gates of the estuarine barrage operated depending on the tide level during spring tide, but they were constantly open during neap tide. Water temperature and salinity fluctuated regularly with intermittent discharges of freshwater, whereas they were stable while freshwater discharge was continuous. Mean salinity was 29 during the study period. Salinity exceeded the mean value in the normal season and rapidly recovered after a temporary reduction. In contrast, water with salinity below the mean value prevailed in the estuary for three months over the rainy season. These results indicate that water temperature and salinity were affected by the amount of freshwater discharge, as well as the frequency of discharge on a large scale and the time over which the freshwater discharge continued.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.11-20
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• 2008

The spillway type of small and midsize dams in Korea is almost overflow weir. To examine flood control capacity of overflow spillway, FLOW-3D was applied to Daesuho dam and analysis was focused on the discharge of dam spillway by changing weir shape. Overflow phases and discharges of linear labyrinth weir and curved labyrinth weir were compared with those of existing linear ogee weir. Hydraulic model experiment was performed to verify numerical result. Verification results showed that overflow behaviors and flow characteristics in the side channel by hydraulic model experiment and numerical simulation are well matched, and water surface elevation at side wall coincides with each other. When the reservoir elevation was increased up to design flood level, in case of the linear ogee weir the flow over the crest ran through smoothly in the side channel, whereas in cases of linear labyrinth weir and curved labyrinth weirs, the flow discharge was increased by 40 cms, and the flow over the weir crest, rotating counter-clockwise, was submerged in the side channel. The results of the water level-discharge curve revealed that labyrinth weir can increase discharge by 71% compared to the discharge of linear ogee weir at low reservoir elevation since it can have longer effective length. But as water surface elevation rises, the slope of water level-discharge curve of labyrinth weir becomes milder by submergence and nappe interference in the side channel.

• Journal of Environmental Science International
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• v.21 no.6
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• pp.667-676
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• 2012

This research investigated to reduce mass of heavy metals in AMD(acid mine drainage) by microbial mats formed on the channel bed. As, Cd, Cu, Fe, Mn and Zn components were monitored in water and microbial mats, at three points (AMD1, AMD2 and AMD3), in a total of six times. Average daily discharge mass of heavy metals was highest in July, Fe component contained more than 76% of total discharge mass. Discharge mass of heavy metals of AMD and heavy metal contents in microbial mats decreased with downstream at channel. Heavy metal components that average daily discharge mass is over 0.5 kg were Fe, Cu and Zn, and they were highest in July. Average removal efficiency of heavy metals in AMD was highest about 21% in Fe, this microbial mats were due to form from precipitation of Fe component in AMD by aerobic iron bacteria. Relative content for As component in microbial mats than AMD was over 16 times, this As components were due to absorb at iron oxide and iron hydroxide on the surface of microbial mats.

• Journal of Korea Water Resources Association
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• v.48 no.11
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• pp.957-967
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• 2015

It was reviewed for the 2D numerical simulations to evaluate the effects of flood control by detention basin, even if stage-discharge relationships for the side weir were not known. A 2D depth-integrated numerical model was constructed by the application of the finite volume method to the shallow water equations as a numerical method and the introduction of an approximate Riemann solver for the accurate calculation of fluxes. Results by the model were compared with those by the laboratory test for the cases of free overflow and submerged flow over a side weir between the channel and storage. The difference between simulated and measured discharge coefficients for the case of free overflow is very small. In addition, the results by simulations were in good agreement with those by experiments for the submerged flow over a side weir and its mechanism was reproduced well. Through this study the discharge coefficients of side weirs can be accurately determined by the 2D numerical model and a considerable degree of accuracy can be achieved to evaluate the effect of flood defenses by detention basins. Thus, it will be expected to apply this model practically to the plan of detention basins, the evaluation of design alternatives, or the management of the existing ones.

• Journal of Veterinary Clinics
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• v.36 no.1
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• pp.38-41
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• 2019

The aim of this study was to estimate of prediction of whelping day and to confirm the accuracy of prediction of whelping day in small pet bitches. The gestation length from the each based on days was $66.64{\pm}2.32days$ ($Mean{\pm}S.D$) when the Cornification index (CI) was over 90% after the first vaginal discharge, $64.65{\pm}2.87days$ from the day of CI peak, $63.46{\pm}1.63days$ from the day of ovulation by progesterone concentrations, and $57.67{\pm}2.43days$ from the first day of cytologic diestrus, respectively. The whelping day was estimated 66 days when the CI was over 90% after the first vaginal discharge, 64 days from the day of CI peak, 63 days from the day of ovulation by progesterone concentrations, and 57 days from the first day of cytologic diestrus, respectively. The accuracy of the prediction of whelping day was 90.0% with a precision of ${\pm}2days$ when the CI was over 90% after the first vaginal discharge, 77.5% from the day of CI peak, 86.2% from the day of ovulation by progesterone concentrations, and 81.2% from the first day of cytologic diestrus, respectively. These results indicated that the prediction of parturition day by vaginal cytology was useful method for management of reproduction and parturition in small pet bitches.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.493-497
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• 2000

A battery is the device that transforms the chemical energy into the direct-current electrical energy without a mechanical process. Unit cells are connected in series to obtain the required voltage while being connected in parallel to organize capacity for load current. Because the voltage drop down in one set of battery is faster than in two one it may result in the low efficiency of power converter with the voltage drop and cause the system shutdown. However when the system being shutdown. However when the system being driven in parallel a circular-current can be generated,. It is shown that as a result the new batteries are heated by over-charge and over-discharge and the over charge current increases rust of the positive grid and consequently shortens the lifetime of the new batteries. The difference between the new batteries and old ones is the amount of internal resistance. In this paper we can detect the unbalance current using the microprocessor and achieve the balance current by adjusting resistance of each set, The internal resistance of each set becomes constant and the current of charge and discharge comes to be balanced by inserting the external resistance into the system and calculating the change of internal resistance.

• Journal of Ocean Engineering and Technology
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• v.21 no.6
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• pp.87-94
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• 2007

This study used POM (Princeton ocean model) improved for applying to coastal area in order to predict the distribution of thermal waste water. This model was applied to the coastal circulation and the effect of thermal waste water of Cheonsu-Bay. So this study compared the discharge of thermal waste water with each layer and section. The tidal current was about 1.5 m/sec at surface level and 0.9 m/sec on bottom level at flood tide; tidal current was about 1.3 m/sec on surface level and 0.8 m/sec on bottom level at ebb tide. The method discharging the thermal waste water in the nearshore region (case 1) accelerates the diffusion of the thermal waste water in the north-south direction(longshore direction). However, the method discharge the thermal waster water in the offshore region (case 2) reduced the diffusion of the thermal waste water over the coastal region. According th the diffusion region of the thermal waste water with case 1 and case 2 at three different layers (surface, middle, bottom), the diffusion region by case 1 discharge method generally influenced wider region (twice) than the one by case 2 discharge method with lower temperature between $1^{\circ}C\;and\;2^{\circ}C$, whereas the case 2 discharge method influenced the deeper region (middle and botton layers) with higher change of the water temperature ($1{\sim}3^{\circ}C$).

• Textile Coloration and Finishing
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• v.11 no.1
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• pp.16-24
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• 1999

The effects of two-step fixation of steaming and baking on the dischargeability of cotton fabrics dyed with C.I. Reactive Black 5(Bl-5) were investigated when the concentrations of $K_2CO_3$ and benzaldehyde sodium bisulfite(BASB) were increased over 120/kg. Remarkably increased dischargeability resulted from baking for 3 min or more at 160t after steaming for 8 min or more at $102^\circ{C}$, but 120g/kg or more amounts of $K_2CO_3$ and BASB(50%) had little influence on dischargeability. Therefore the discharge mechanism can be suggested that covalent bonds between cellulose and Bl-5 undergo $S_N2$ attack by hydroxide ion formed by the reaction of $K_2CO_3$ and water in steaming at $102^\circ{C}$ first and then, through transition states they are cleavaged in baking at 160t to yield hydrolyzed Bl-S and compounds of BASB and Bl-5 isolated from fiber, which are undyeable and removed by washing. The effect of urea, one of the hydrotrope agents, on discharge printing was also studied. The result which dischargeability was greatly improved by increasing the steaming time from 8 min to 15 min at $102^\circ{C}$ or by increasing the amount of urea obviously shows that water in steaming and urea in print paste play an important role in discharge printing. And as an increase of the baking time from 5 min to 7 min at $160^\circ{C}$ makes it possible to improve dischargeability, it is once more confirmed that high temperature of about 160t is exactly required to discharge the dyed Bl-5. The colored discharge printing demands a more amount of urea because urea contributes to the putting color fixation as well as the discharge reaction.