• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.2
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• pp.63-70
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• 1997

It has been observed that local increase in melanin synthesis or uneven distribution can cause local hyperpigmintation or spot. Pigmentary disorders are caused by various factors, including inflammation, imbalance of hormones, and genetic disorder. Recently the harmfulness of Ultraviolet radiation is increasing due to destruction of ozone layer. Excessive exposure to UV radiation caused post-inflammatory pigmentation. Most women want to avoid uneven skin pigmentation. To satisfy this desire many cosmetic companies have been developing melanogenesis inhibitors and finding promising active agents for use in cosmetic preparations for skin whitening. In cosmetic preparations, many inhibitors such as kojic acid, arbutin, ascorbic acid, and licorice extracts6 have been used as whitening purpose. Plant extracts having an inhibitory effect on melanin formation may be a good choice for cosmetic purpose because of their relatively lower side effects. Therefore, we screened 285 plant extracts for their inhibitory activity in tyrosinase. Of the plant extracts, ramulus mori extracts showed potent tyrosinase inhibition activity. We also identified the active compound in the extract.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.10
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• pp.1347-1354
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• 1999

Recently, the markets of the air conditioner are enlarging. The market size will reach 2.0 billion won in 2000. Electric heat pumps have been utilized as main residential air conditioners. especially in Korea. They cause a surge up electric power demand during summer. Moreover, the use of HCFCs and HFCs causes serious problem to the global environment such as global warming and ozone layer destruction. Absorption chiller and heater could solve such problems. It was built and tested for analyzing the performance of the generator for absorption chiller and heater. Experiment was done with a high temperature generator, a low temperature generator, heat exchangers, a condenser and a solution tank. It was tested that the double effect series flow cycle with two kinds of solution cycle. Solution cycle B showed better than solution cycle A. Two kinds of heat exchanger were used, where one's heat transfer area is bigger than the other. Bigger one increased a little performance of absorption chiller and heater. But it was not economical. From this study, we got that the coefficient of performance(COP) is 0.82 and the capacity is 7.24 kW for an absorption chiller and heater.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1361-1364
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• 1990

In order to tackle global environmental problems such as destruction of the ozone layer or climatic changes due to atmospheric temperature increase, the acquisition of plentiful and precise data is necessary. Therefore, a means of conducting long-lasting high-resolution measurements over broad areas is required. A feasibility study has been made on a high altitude (20km), super-pressured helium-filled PLTA (Powered Ligher-than-Air) vehicle as an ideal platform for environmental observation. It has a long service life and carries a larger payload than an artificial satellite. This PLTA platform uses an electric propulsion system to maintain position in space against wind currents. The thruster is driven by solar power acquired from solar cells. For night use, solar energy is stored in regenerative fuel cells. This study focuses on energy balance and structural analysis of the hull and platform. The platform is capable of conducting high resolution remote sensing as well as having the capability to serve as a telecommunications relay. The platform could replace a number of ground-based telecommunications relay facilities, guaranteeing sufficient radio frequency intensity to secure good quality telecommunication transmittal. The altitude at which the platform resides has the lowest wind flow in the lower stratosphere, and permits viewing from the ground within a 1,000km range. Because this altitude is much lower than that required of an artificial satellite, the measuring resolution is a couple of thousand times higher than with artificial satellites. The platform can also be used to chase typhoons and observe them from their sources in tropical regions.

• Journal of the Korean Applied Science and Technology
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• v.12 no.2
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• pp.157-163
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• 1995

The ultraviolet blocking agents used to skincare are largely classified ultraviolet scattering agent and ultraviolet absorbent agents. There are UVC, UVB, and UBA in ultraviolet ray(UV) showing shorter wavelength than visible light. Both visible light and UVA give rise to 1st dark-skinned phenomena. On exposure of the skin to UV, phenomena of skin variation are termed sunburn or suntan. There are chronic and acute adverse reactions in skin response to UV. The latter is caused by UVB, which has mainly effects on the skin. But lately due to destruction of ozone layer, UVA has more serious irritation on the skin than UVB. In this paper spectrometric properties of UV absorbent agents such as PABA, octyl-PABA, Urocanic acid, and 2-hydroxy-4-methoxy benzophenone in vitro have been investigate. As results, it was found that the three fomer were more suitable than the last. UV scattering measurements on the sample used inorganic pigments showed that pigments containing titanium dioxide had a better scattering effects than the inorganic pigments such as $Fe_2O_3$, $Al_2O_3$, etc.

• Journal of Power System Engineering
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• v.19 no.6
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• pp.68-74
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• 2015

NOx emission has been controlled because it is a major cause of the acid rain and effects considerably on formation and destruction of ozone. A SCR system on diesel engine is necessary to clear TierIII, because IMO(International Maritime Organization) plans on tightening regulations to TierIII at $1^{st}$ January 2016. In this study, flow analysis was accomplished with ANSYS Fluent program so that the SCR system would be retrofitted in training ship KAYA and the temperature distributions of exhaust gas in SCR sytem were investigated after it was installed. As a result, it was confirmed that pressure and velocity distributions in SCR system were depended on pipe line shapes, then it was designed as the pressure was lower. The temperature differential between 1 and 3 point was $15^{\circ}C$ because of evaporative latent heat of urea and the temperature of 4 point after catalyst was increased by $5^{\circ}C$ than 3 point because of exothermic reaction.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.4
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• pp.733-738
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• 2020

In the recent years, the development of coastal zone has been advancing, and the chance of leisure activity has increased near the sea. However, the destruction of ozone layer has resulted in an increase in the amount of ultraviolet radiation reaching the earth surface. The human body is harmfully influenced as skin cancer and eye damage by ultraviolet radiation. Especially, the effect of ultraviolet radiation on beach is higher than that inland area due to the reflection from the sand. This study is expected to use basic data on the method of measuring ultraviolet reflections on east coast beaches using remote sensing.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.499-506
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• 2022

With the construction of the northern line of the East Sea in 2021, expectations for peaceful use of the Demilitarized Zone (DMZ) are rising. Accordingly, it is necessary to prepare for leisure tourism activities at nearby beaches using the Demilitarized Zone as a security ecological tourism. However, despite the increase in the amount of ultraviolet rays on the surface due to the destruction of the ozone layer, there are no guidelines for UV exposure. In this paper, the amount of ultraviolet reflection on the coast adjacent to the DMZ using remote exploration was measured and analyzed. It is hoped that the presented results will be used as basic data to prepare UV guidelines for leisure tourism activities in nearby areas.

• Applied Chemistry for Engineering
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• v.18 no.4
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• pp.314-319
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• 2007

The destruction of synthetic acetic acid wastewater was carried out using UV, $O_3$, $H_2O_2$, $Fe^{2+}$ oxidants in various combinations by the advanced oxidation processes. $UV/H_2O_2$, $UV/H_2O_2/Fe^{2+}$, $O_3$, $O_3/H_2O_2$, $UV/O_3/H_2O_2$, $UV/O_3/H_2O_2/Fe^{2+}$ processes were tested. $UV/H_2O_2/Fe^{2+}$, $O_3/H_2O_2$, $UV/O_3/H_2O_2$, $UV/O_3/H_2O_2/Fe^{2+}$ processes shows the most effective destruction efficiency at low pH (3.5) condition of wastewater, but $UV/H_2O_2$ and $O_3$ processes were observed less than 20%. Destruction efficiency was gradually increased with the reaction time in the $O_3/H_2O_2$ and $UV/O_3/H_2O_2$ processes, in case of the $UV/H_2O_2/Fe^{2+}$ and $UV/O_3/H_2O_2/Fe^{2+}$ processes shows rapid increasing of destruction efficiency within 90 min, then slightly decreasing with time. The destruction efficiencies of $UV/H_2O_2/Fe^{2+}$, $O_3/H_2O_2$, $UV/O_3/H_2O_2$ and $UV/O_3/H_2O_2/Fe^{2+}$ processes were observed 55, 66, 66 and 64%, respectively.

• Clean Technology
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• v.14 no.3
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• pp.184-192
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• 2008

Fluoride-type cleaning agents such as 2,2,2-trifluoroethanol (TFEA) and hydrofluoroethers (HFEs) do not destroy ozone in the stratosphere and have low global warming potential compared to hydrofluorocarbons(HFCs) and hydrochlorofluorocarbons (HCFCs). Especially, HFEs which have no flash point are paid attention as next generation type of cleaning agents for chlorofluorocarbons (CFCs) since they are safe in handling and have excellent penetration ability compared to hydrocarbon cleaning agents with low flash point. Here, the physical properties and cleaning abilities of fluoride-type cleaning agents such as TFEA, HFE-7100, HFE-7200, HFE-476mec, HFE-449mec-f, AE-3000 and AE-3100E and silicide-type cleaning agents such as trifluoroetoxytrimethylsilane (TFES) and hexamethyldisilazane (HMDS) were measured and compared with those of ozone destruction substances such as CFC-113 and 1,1,1-trichloroethane. They were also compared with toxic methylene chloride (MC) and isopropyl alcohol (IPA) which are now being used as an alternative cleaning agents. As a result, TFEA and HFEs had lower cleaning ability for removal of various soils compared to chloride-type cleaning agents, but they showed excellent cleaning ability fur fluoride-type soils. TFES and HMDS also showed excellent cleaning ability for silicide-type soils.

• Journal of the Korean Chemical Society
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• v.58 no.6
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• pp.590-599
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• 2014

Environmental education, effectively performed at school, is very important to solve the environmental problems. Moreover the survey for teacher's perception is essential. The purpose of the study was to investigate the perception of environmental problems of middle school teachers in Pusan. The survey was done twice in 2007 and 2012, and based on the time intervals, careers, and major of the teachers. 200 teachers were chosen in 2007 and 300 teachers in 2012. How many environmental problems occurred during this time period affected the 471 teachers' perception was investigated and analyzed. The results are as follows. First, the perception difference of environmental problems was meaningful between two time intervals (p<.01). Especially, the perception of modern environmental problems and carbon emission showed considerable increase in both science and non-science major teachers. This may be caused by the climate change and the severity of lifestyles of indiscriminate consumerism. Second, the perception difference of environmental problems by careers was also meaningful (p<.01). Overall, the perception was obvious on the aspects of modern environmental problems, carbon emission, destruction of ozone layers, nuclear wastes, environmental hormones, and red tides. Teachers, having more careers irrespective of their teaching subjects, showed higher perception on the seriousness of environmental pollution, the necessity of environmental conservation, and the importance of health. Third, the perception of environmental problems between science and non-science major teachers was meaningful (p<.01). Particularly, the perception in the broad environmental problems was distinctive between them.