• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.2 s.23
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• pp.103-108
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• 2005

For the development of a disk type oil skimmer for a tank lorry, a basic study on comparison of oil recovery performance between disk materials of oil skimmer was conducted. The experiment results are summarized as follows: In all the disks, the volume of recovery of bunker-A oil was greater than diesel oil. In light oil, there was nearly no differences in the volume of oil recovery by disk material, but in the case of bunker A oil, recovery efficiency showed big differences depending on the disk materials. For diesel oil, the differences in the volume of oil recovery per unit of operation time from the initial time zone were hardly shown. However, the volume of recovery of bunker-A oil linearly increased from the initial operation time in all the disks and the increase showed a slew moving trend as time. went on; therefore, the volume of oil recovery per unit of operation time showed differences depending on time. This result shows that oil viscosity has an effect on the disk recovery efficiency. When comparing the mass of pure oil recovery and the volume of water recovery in the total mass of recovery by bunker-A oil, there was no difference in the volume of oil recovery between the window-aluminum material disk and the disks consisting of other materials, but the volume of water recovery of the former was relatively very small This shows the most ideal result in view of oil recovery efficiency that considers the volume of water recovery. In conclusion, it was found that aluminum is the most advantageous as the material for tank lorry oil skimmer disk.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.533-534
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• 2002

In this paper, we studied the transient gain response in TDFA(Thulium-Doped Fiber Amplifier) theoretically. We also investigated the limitation of the gain saturation and recovery time when the short pulse trains are incident into the TDFA with the spectral gain band in 1.47${\mu}{\textrm}{m}$ for using at WDM. We can predict the interval between the pulse train, pump power and the effect of the saturation and recovery time which is affected to the amplification of the optical pulse.

• Korean Journal of Exercise Nutrition
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• v.13 no.3
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• pp.211-216
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• 2009

This study was conducted to investigate the changes of exercise-induced stress response with acute anaerobic exercise in elite soccer players of university. The subjects were divided into elite soccer players of university (SG, n=10) and control group (CG, n=10). Subjects were tested three consecutive Wingate test for 30 seconds involving 2 times of 3 mins of resting time. In addition, whole blood and capillary blood were collected at rest, immediately post-exercise and 60 mins. of recovery time. Obtained results were as follows: Evaluated mean power and peak power of SG group was significantly higher than that of CG group in the all phase of Wingate test, respectively (p<.01). Although resting serum TG, TC, HDLC levels were not significant difference between SG and CG group, resting serum glucose of SG group was significantly lower than that of CG group. In addition, serum CRP levels of SG group were significantly lower than that of CG group at rest, immediately post-exercise and 60 mins of recovery time, respectively (p<.01). In serum cytokines, in spite of no significant differences in IL-1β levels between SG and CG group, IL-6 levels of SG group were significantly lower than that of CG group at immediately post-exercise and 60 mins. of recovery time, respectively (p<.05, p<.01). From these results, long-term combination training have a crucial role in amelioration of acute exerciseinduced stress response in elite soccer players.

• Environmental Engineering Research
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• v.23 no.2
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• pp.175-180
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• 2018

Box-Behnken Design (BBD) under response surface methodology (RSM) was implemented to optimization the operating parameters and assess the removal and recovery efficiencies of crude oil from contaminated soil using subcritical water extraction. The effects of temperature, extraction time and water flow rate were explored, and the results indicate that temperature has a great impact on crude oil removal and recovery. The correlation coefficients for oil removal ($R^2=0.74$) and recovery ($R^2=0.98$) suggest that the proposed quadratic model is useful. When setting the target removal and recovery (>99%), BBD-RSM determined the optimum condition to be a temperature of $250^{\circ}C$, extraction time of 120 min, and water flow rate of 1 mL/min. An experiment was carried out to confirm the results, with removal and recovery efficiencies of 99.69% and 87.33%, respectively. This result indicates that BBD is a suitable method to optimize the process variables for crude oil removal and recovery from contaminated soil.

• Korean Journal of Pharmacognosy
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• v.18 no.4
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• pp.216-232
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• 1987

In order to investigate the preventive and therapeutic effects of Herba Houttuyniae, experimental studies on the immune response and histological findings were undertaken. The results of these studies were summarized as follows; Delayed type hypersensitivity and rosette formation rate were significantly increased compared with control group. Hemagglutination, hemolysin titer and NK cell activity were variable, not significantly against the control group. When observed on lung tissue recovery; experimental groups were shown to be significantly recovered as compared with the control group. From these results, it is suggested that Houttuyniae Herba promotes immune response and reduces the recovery time of pneumonitis and lung abscess from the histological viewpoint.

• Korean Journal of Materials Research
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• v.21 no.4
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• pp.232-235
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• 2011

ZnO nanorods for gas sensors were prepared by a hydrothermal method. The ZnO gas sensors were fabricated on alumina substrates by a screen printing method. The gas-sensing properties of the ZnO nanorods were investigated for $CH_4$ gas. The effects of growth time on the structural and morphological properties of the ZnO nanorods were investigated by X-ray diffraction and scanning electron microscope. The XRD patterns of the nanocrystallized ZnO nanorods showed a wurtzite structure with the (002) predominant orientation. The diameter and length of the ZnO nanorods increased in proportion to the growth time. The sensitivity of the ZnO sensors to 5 ppm $CH_4$ gas was investigated for various growth times. The ZnO sensors exhibited good sensitivity and rapid response-recovery characteristics to $CH_4$ gas, and both traits were dependent on the growth time. The highest sensitivity of the ZnO sensors to $CH_4$ gas was observed with the growth time of 7 h. The response and recovery times were 13 s and 6 s, respectively.

• Journal of Sensor Science and Technology
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• v.32 no.4
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• pp.207-212
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• 2023

H₂S is a toxic and harmful gas, even at concentrations as low as hundreds of parts per million; thus, developing an H₂S sensor with excellent performance in terms of high response, good selectivity, and fast response time is important. In this study, an H₂S sensor with a high response and fast response time, consisting of a sensing material (SnO₂), an electrode, a temperature sensor, and a micro-heater, was developed using micro-electro-mechanical system technology. The developed H₂S sensor with a micro-heater (circular type) has excellent H₂S detection performance at low H₂S concentrations (0-10 ppm), with quick response time (<16 s) and recovery time (<65 s). Therefore, we expect that the developed H₂S sensor will be considered a promising candidate for protecting workers and the general population and for responding to tightened regulations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.79-82
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• 1994

We have manufacture Copper-tetra-tert-butylphalocyanine (CuTBP)Langmuir-Blodgett(LB) films, which is known be sensitive to NO$_2$ gab. A response of these films to the NO$_2$ gab was studied. A surface pleasure of 25mN/m was obtained as a proper one for a film deposition. A deposited film status was identified with Uv/visible absorption spectra, ellipsometry measurements, and current-voltage(I-Y) characteristics. The NO$_2$ gas response experiments under 200ppm conducentration show that there are increment of electrical conductivity by 12 times, 5 seconds of response time, and 5 seconds of response time, and 90 seconds of recovery time.

• Electrical & Electronic Materials
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• v.10 no.3
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• pp.233-238
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• 1997

We have investigated gas-detection characteristics of CuTBP (Copper-tetra-tert-butylphthalocyanine) chemiresistor devices exposed to air/200ppm N $O_{2}$ gases. The CuTBP films were made by Langmuir-Blodgett (LB) techniques. Sensitivity, response time, recovery time, and reproducibility of the devices were measured by current voltage characteristics. Interdigital electrode was used to improve the sensitivity. It was observed that a conductance G increases monotonically as the number of interdigital electrode finger pairs increases. As the number of interdigital electrode finger pairs increases, the sensitivity S( $G_{gas}$/ $G_{air}$) increases more than 50 times and stable. But the response time was delayed. The average recovery time of the CuTBP chemiresistor devices turned out to be about 100 second. We have also investigated applicability of the CuTBP chemiresistor device for a gas sensor.sor.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.413-421
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• 2014

Since the structural temperature of a flight vehicle flying at high speed rises rapidly due to aerodynamic heating, it is necessary for optimum structural design to obtain proper material properties at high temperature by taking into account of its operational environment. For a special alloy, analysis data on strength change due to exposure time to high temperature are very limited, and most of them are for an exposure time longer than 30 minutes for long term operations. In this study, base and weld metal samples of Ti-6Al-4V alloy had been prepared and high temperature tensile tests with induction heating were performed, and then high temperature strength characteristics and strength recovery characteristics through cooling have been analyzed. Pre-tests to determine maximum heating rate were performed, and response characteristics for temperature control were confirmed. As a result, high temperature tensile strength appeared to be lower than that of room temperature, but it was higher than that of high temperature of 30 minite exposure listed in MMPDS. In strength recovery through cooling Ti-6Al-4V alloy has shown higher recovery rate compared with other alloys.