• Journal of the Korean Vacuum Society
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• v.19 no.3
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• pp.169-176
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• 2010

Cryopumps can provide economical profits with a relatively high pumping speed per size. However, it is somewhat doubtful that pumping performance of cryopums, which is very sensitive to the temperature of the adsorption panel, can be maintained or recovered fast for large continuous or impulsive gas loads. The official evaluation items indicating cryopump performance for gas loads are the maximum throughput and the crossover value. There are two other, unofficial but widely used, items, the Ar recovery time and gulp characteristics. Although these evaluation items look absolutely different with each other, there are close relations and even duplications in their test schemes. Therefore, it is necessary to study how to improve practically each test procedure, and combine or unify some procedures.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1990.06a
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• pp.322-325
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• 1990

• Journal of Embryo Transfer
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• v.19 no.3
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• pp.283-289
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• 2004

This study was conducted to determine the effects of incubation time after cooling on mouse meiotic spindle and chromosome alignment and the optimal incubation time for their restoration. Oocytes at the metaphase II were obtained from superovulated mice. Control oocytes were held at 37$^{\circ}C$ during the experiment. Oocytes were rapidly cooled to $0^{\circ}C$, held for 30 minutes, warmed and incubated at 37$^{\circ}C$ for 5, 15, 30, 60 and 120 minutes, respectively. The morphological features of spindle and chromosomes in oocytes were evaluated by immunofluorescent staining. Meiotic spindle of control oocytes exhibited a normal-looking bipolar configuration(barrel-shaped) and highly fluorescent microtubles. The chromosomes were clustered in a discrete bundles at metaphase plate. Disassembly of meiotic spindle and chromosome dispersion were occurred immediately after chilling of oocyte. Fluorescence intensity index(FIS), normal chromosomes aligned and normal spindle configuration were compared according to incubation time at 37$^{\circ}C$. Restoration of a barrel-shaped spindle and normal chromosome alignment was occurring after 5 minutes incubation at 37$^{\circ}C$, improved as a incubation time increased, and decreased gradually after 120 minutes incubation(P<0.05). The optimal incubation time for restoration of meiotic spindle and chromosomes in cooled oocytes was 60 minutes.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.3
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• pp.234-240
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• 2010

The effectiveness of adding powdered zeolite and granular activated carbon (GAC) before starvation into biological reactor for recovering its performances was investigated. Two types of carrier addition in Sequencing Batch Reactor (SBR) system for non-saline and saline wastewater were evaluated after starvation periods. During the experiment, settleablity (SVI), floc size, fractal dimension, $COD_{Mn}$, T-N, T-P removal efficiencies and recovery time were monitored. When the wastewater feeding was resumed after starvation period for 5days, the SVI increased at the beginning of resumption and then decreased with time in both types. And the larger the floc size and fractal dimension of floc, the more increased removal efficiency for $COD_{Mn}$, T-N and T-P was also. Its performance recovery was strongly correlated with floc size and fractal dimension of activated sludge. After resuming the wastewater feeding, the SVI, floc size, fractal dimension, $COD_{Mn}$, T-N, T-P removal efficiency of SBR with carrier improved and reached its initial value faster compared to those of SBR without carrier.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.139-143
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• 1987

This experiment was conducted to investigate the effect of herbicide on the photosynthetic activity of the weed and rice plant. Two rice cultivars "Nongbaeg" and "Taebaegbyeo" were tested with butachlor, Molis-M, and perfluidone at 5 days after transplanting. Bentazone and propanil were sprayed at 25 days after transplanting. Photosynthetic activity was varied with herbicide and varieties. Generally, application of herbicide resulted in decreased photosynthetic activity. Indica ${\times}$ Japonica variety showed more sensitive to herbicide than Japonica variety. Recovery of the photosynthetic activity was faster in the bentazon than the propanil.

• Journal of the Korean Society of Radiology
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• v.11 no.3
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• pp.147-151
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• 2017

Potentially lethal damage repair (PLDR) in HFL-I was investigated by delayed plating experiments. The surviving fraction data were fitted to the linear Quadratic equation ($LogSn=-n{\gamma}({\alpha}d+{\beta}d^2$) where ${\gamma}=1$ for immediate plating). And a repair factor ${\gamma}$ was developed to compare survival for immediate and delayed plating. When we only took into account the repair factor of PLDR ${\gamma}$ which was derived from the delay assay, the cell survival response th fractionated carbon ion irradiation was not fully matched. This gap suggested that consideration of another repair process is necessary. So this suggests that the various repair process plays an important role in the fractionated irradiations.

• Journal of Navigation and Port Research
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• v.36 no.5
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• pp.371-378
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• 2012

This paper presents a timing recovery method using Gardner TED (Timing Error Detector) with a Peak Detector using Parabola Peak Interpolation in underwater acoustic communication. This method will have an eye to improve phase converge speed of timing recovery and reduced amount of Tx data. The OQPSK(Offset Quadrature Phase Shift Keying) modulation technique was considered. The proposed algorithm has faster recovery speed and more accurate than Gardner TED because the sampling values in the proposed algorithm are moved persistingly to maximum or minimum point using parabolic peak interpolation. when simulation performed using Preposed method, it improved BER (Bit Error Rate) performance about 23% And to evaluate the performances of the proposed algorithm the sea trial was performed in the Korean East Sea. And distance of a transmitter-receiver is 3 km each other. As a result, the proposed algorithm outperforms better BER performance about 20% of timing recovery than the Gardner method. Also Proposed method improved converge speed of timing recovery about 1.4 times better than Gardner method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.233-240
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• 2005

In this paper, we have shown the gain recovery time of erbium-doped fiber amplifier(EDFA) in WDM add/drop networks can be reduced to less than $3\mu$sec by employing disturbance observer technique with PID controller which is based on 3-level EBFA model. The $3\mu$sec transient time is the fastest one ever reported and it is about $1\%$ of $250\mu$sec previously obtained from disturbance observer technique with PI controller which was based on 2-level EDFA model and it is also less than $200\mu$sec of commercially available EDFAs for WDM networks. We were able to obtain this result by analyzing various system characteristics as we change the parameters of disturbance observer and PID controller. If this result is applied to a commercial product, the product will do an important role in the future dynamic WDM networks.

• Journal of Sericultural and Entomological Science
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• v.28 no.1
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• pp.61-65
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• 1986

This work was to realize the wrinkling behavior of spun silk fabric. The results were obtained through the various conditions such as temperature, wrinkling time, wrinkling load and crease recovery time. The obtained results were summerized as follows : 1. Wrinkle recovery of the silk fabric was decreased with the increase of temperature, humidity and the influence of humidity was superior to the influence of temperature. 2. The change of wrinkle recovery depending on the wrinkle recovery time showed the experimental equation (Y=a+b lnT). The wrinkle recovery increased with the lapse of wrinkle recovery time but arrived at the equilibrium position about 300 sec. 3. The value "K1" of the silk fabric in the "Voigt model" was inferior as compared with the polyester and Nylon. 4. The change of wrinkle recovery depending on the wrinkling time was decreased with the lapse of wrinkle recovery time but the change of the value "a" could not be fined. 5. The change of wrinkle recovery depending on the wrinkling load was same as above 4.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.409-419
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• 2022

The purpose of this study was to investigate how the increased sedentary behavior due to COVID-19 on physical factors to maintain health. The subjects of the study were 33 office women who mainly lead a sedentary behavior. The group settings were divided into high sedentary behavior groups(n=11), middle sedentary behavior groups(n=11), and low sedentary behavior groups(n=11) according to the hours of sitting down living. There was no significant difference between the groups in the VO₂max and EPOC, the level of lactate in blood showed a significant difference immediately after exercise(p<.05) and at 15(p<.001) and 20(p<.001) minutes of recovery, and the degree of recovery was more smooth in the low sedentary behavior groups. These results suggest that the difference in time according to the degree of sedentary behavior will affect the factors for maintaining health. Therefore, it is considered necessary to minimize sedentary behavior time even in the COVID-19 situation where the time spent in a personal space increases.