• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.464-469
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• 2019

A remote monitoring panel and control system was developed to control various valves and access control chambers, including gas shutoff valves used in CBR(Chemical, Biological and Radiological) facilities. The remote monitoring panel consisted of a main panel installed in the NBC (Nuclear, Biological and Chemical) control room and auxiliary panel installed in the clean room, and the size was divided into pure control and control including CCTV. This system can be monitored and controlled remotely according to the situation where an explosion door and gas barrier door can occur during war and during normal times. This system is divided into normal mode and war mode. In particular, it periodically senses the operation status of various valves, sensors, and filters in the CBR facilities to determine if each apparatus and equipment is in normal operation, and remotely alerts situation workers when repair or replacement is necessary. Damage due to the abnormal operation of each device in the situation can be prevented. This enables control of the blower, supply and exhaust damper, emergency generator, and coolant pump according to the state of shutoff valve and positive pressure valve in the occurrence of NBC, and prevents damage caused by abrupt inflow of conventional weapons and nuclear explosions.

• Korean Journal of Environmental Agriculture
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• v.38 no.2
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• pp.110-118
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• 2019

BACKGROUND: Residual organochlorine pesticides (OCPs) are designated as persistent organic pollutants (POPs) by Stockholm Convention because they bioaccumulate through the food web, and pose a risk of causing adverse effect to human health and the environment. Apple and pear is economic crop in agriculture, and its cultivation area and yield has been increased. Therefore, we tried to investigate the OCPs residue in apple and pear orchard soils and fruits. METHODS AND RESULTS: Extraction and clean-up method were developed using the modified QuEChERS method for residual organochlorine pesticides (ROCPs) in apple and pear orchard soil and fruits. Recovery and limit of quantitation (LOQ) of ROCPs in soil and fruits were 75.4-101.4 and 76.9-93.4%, 0.03-0.21 and $0.6-1.2{\mu}g/kg$, respectively. Detected ROCPs in apple and pear orchard soil was 2,4-DDT, 4,4-DDD, 4,4-DDE, 4,4-DDT, and endosulfan sulfate, the residues were 2.2, 1.9-48.0, 1.3-84.1, 90.6-863.1, and $11.3-239.0{\mu}g/kg$, respectively. But five pesticides in all fruit samples were not detected. CONCLUSION: These results showed that ROCPs residues in apple and pear orchard soil had no effect on safety of agricultural products.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.61-68
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• 2019

As the pollution of water resources deteriorates due to industrialization and urbanization, it is difficult to supply clean water through a water treatment method using chlorine. Therefore, the introduction of advanced water treatment facilities using ozone is on the increase. However, epoxy which is used as waterproofing and anticorrosives and stainless steel used in conventional waterproofing and anti-corrosive methods have deteriorated because of the strong oxidizing power of ozone, causing problems such as leaking. Moreover, it even causes the durability degradation of a concrete. Therefore, in this study, metal spraying system was used as the means of constructing a metal panel with excellent ozone resistance and chemical resistance which is an easier method than an existing construction method. Ozone resistance was evaluated in accordance with the type of metal sprayed coatings to develop a finishing method which can prevent the concrete structure of water treatment facilities from deterioration. Furthermore, electrochemical stability in actual sewage treatment plant environment was evaluated. Experimental results showed that Ti has superior ozone resistance after spraying and the electrochemical stability in the sewage treatment plant environment showed that Ti has the highest polarization resistance of $403.83k{\cdot}{\Omega}{\cdot}cm^2$, which ensures high levels of durability.

• Particle and aerosol research
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• v.15 no.2
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• pp.79-90
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• 2019

It is important to control fine particles in children care centers, elementary schools, elderly care facilities and so on where vulnerable children and the aged stay during most of their time. This study has investigated $PM_{2.5}$ and $PM_{10}$ concentrations in two classrooms equipped with an air cleaner and two air cleaners, respectively and they were compared to those in a classroom without an air cleaner as well as those outdoors. Eight air cleaners which have various clean air delivery rates (CADRs) between 9.9 and $21.3m^3/min$ were tested in classrooms in two elementary schools in Seoul. Average $PM_{2.5}$ and $PM_{10}$ were $7.3{\pm}0.7$ and $45.5{\pm}4.1{\mu}g/m^3$ in classrooms equipped with an air cleaner and $4.2{\pm}0.6$ and $24.6{\pm}2.5{\mu}g/m^3$ in classrooms with two air cleaners, whereas they were $22.1{\pm}2.6$ and $109.1{\pm}9.6{\mu}g/m^3$ in classrooms without an air cleaner and $36.9{\pm}5.1$ and $74.1{\pm}10.6{\mu}g/m^3$ outdoors, respectively. $PM_{2.5}$ in classrooms could be reduced effectively by using an air cleaner or two air cleaners, because $PM_{2.5}$ was mainly infiltrated from outdoors, however $PM_{10}$ could not because $PM_{10}$ was mainly caused indoors by students' activities. Air cleaners were more effective for removal of $PM_{2.5}$ and $PM_{10}$ in classrooms with a high airtightness than those in classrooms with a relatively low one. Average $CO_2$ in classrooms was about 1500 to 2000 ppm for class hours dependent on the student number per a classroom, which was about 1.5 to 2 times higher than the standard, regardless of the use of air cleaner.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.336-342
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• 2019

With the entry of an aging society, the average life span of accreditation has been extended. Therefore, interest in the appearance of men and women in modern society has increased. It is the wrinkles of the face that can judge the most outwardly. People tend to have various kinds of treatments to have a clean, wrinkle-free and resilient healthy skin regardless of sex. There is a lot of practice of lifting procedures in one of the procedures. A suture using a melting thread is a method of lifting by squeezing it into the skin as a non-incision type centering on a region where the thread can be fixed in the skin by injecting it into the subcutaneous fat layer. To evaluate the lifting efficacy of Cog - type suture for the improvement of skin wrinkles, preclinical experiments were conducted. We developed a wrinkle evaluation program using Labview. Data from preclinical experiments were used at 8 weeks after suturing. The average wrinkle depth was 415.6 mm in the control group. At 8 weeks, the depth of wrinkles was deepened to 888.3mm due to the aging process of the control group. On the other hand, the depth of the wrinkles before surgery was 640.3 mm in the suture group. It was confirmed that the depth of wrinkles decreased to 566.5mm at 8th week after the suture operation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.177-188
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• 2019

The purpose of the optimization of the installation of supply/exhaust ports for tunnels with transverse ventilation system is to supply fresh air from outside to inside of tunnels uniformly and exhaust pollutant from tunnels properly for creating safe and clean environment for tunnel users. For this purpose, a ventilation port area optimization program was developed to obtain a uniform supply or exhaust air volume inside a great depth double deck tunnel with transverse ventilation system. In order to area optimize the developed port sizing program, the wind velocity was measured in the duct of the currently operated tunnel with semi-transverse ventilation. Also 3D cfd was performed on the same tunnel and cfd results were compared to the measured value. As a result, the error rate between the predicted value from the program and measured value was 6.72%, while the error rate between the predicted value from the program and 3D cfd analysis value was 4.86%. Both of comparison results show less than 10% of error rate. Thus It is expected that supply/exhaust port optimization design of transverse ventilation tunnel can be possible with using this large exhaust port area optimization program.

• Korean Journal of Ichthyology
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• v.31 no.1
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• pp.16-22
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• 2019

Investigations on the study of the distribution aspects and extinction threat evaluation of the Korean endemic species, Iksookimia pacifica were done from 2017 to 2018 in Korea. During the study period, the samples of I. pacifica were collected in 17 streams, 46 sites (from Baebongcheon Stream of Goseong-gun to Gunsuncheon Stream of Gangneung-si) among the noted 33 streams and 104 sampling sites investigated. The population size of I. pacifica was relatively large in streams such as Bukcheon, Baebongcheon, Hwasangcheon, Cheonjincheon, Ohhocheon Stream etc., but the population size was small in streams such as Sacheoncheon, Namcheon, Gangneung Namdaecheon Stream etc. The main habitat of I. pacifica was the downstream pool of clean water with slow velocity and sand bottoms, and their sensibility was estimated to be due to river work and water pollution. Comparing the previous records of the appearance of I. pacifica, they were first seen in Sampocheon Stream, but they did not appear in Jusucheon, Jeoncheon, Samcheok Osipcheon Stream. Given this evidence as noted for the 19.5% reduction in occupancy within 3 generations, in small appearance range ($1,343km^2$) and small occupancy area ($184km^2$), the number of locations were many (18) and the population was relatively large within the range of habitat. Therefore, I. pacifica is now considered a Near Threatened (NT) based on the IUCN Red List categories and criteria.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.123-128
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• 2018

Effect of activators in flux on the printability and wettability of a solder paste was evaluated in this study. The activators in this study were dicarboxylic acids, which were oxalic acid (n = 0), malonic acid (n = 1), succinic acid (n = 2), glutaric acid (n = 3), adipic acid (n = 4), and pimelic acid (n = 5). When the solder pastes were observed with a SMT scope, solder with glutaric acid showed clean and shiny surface when it was melted. Slump ratio of the solder pastes was low when the carbon numbers of the dicarboxylic acid were 1-3. Spreadability was high when the carbon number was over 2. Zero cross time of wetting balance test was under 1 sec when the carbon number was over 3. When activator was oxalic acid or malonic acid, zero cross time was over 1 sec and maximum wetting force was low. Fluxes with the oxalic acid and malonic acid showed decomposition at the temperature close to melting point. Among the dicarboxylic acids, glutaric acid provided excellent slump, spreadability, and wettability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.5
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• pp.364-370
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• 2019

In this paper, an individual blade control (IBC) methodology is applied to find the best input scenario for vibratory hub loads reduction of XH-59A co-axial rotorcraft in high speed flight. A comprehensive aeromechanics analysis code CAMRAD II is employed to analyze the aircraft. A parametric study is conducted for optimum IBC inputs leading to the maximum vibration reduction. Numerical results demonstrate that up to 50% reduction in the hub vibration index is obtained for an IBC input at 3/rev frequency with the amplitude and phase angle of 0.5 deg. and 300 deg., respectively. The upper rotor exhibits as much as 6% more vibration reduction as compared to that of the lower rotor due to a clean inflow characteristic of the rotor. It is found that further vibration reduction gain is reached for IBC inputs with advancing-side only control. The hub vibration becomes reduced by up to 17% in reference to that with full rotor disk control. It is noted that the additional gain is obtained with significantly less power input with the advancing-side only control.

• Korean Chemical Engineering Research
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• v.57 no.3
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• pp.413-419
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• 2019

In the recent, as a world demand of energy resources has been transformed from fossil fuels to hydrogen-based clean energy resources, a huge attention has been attracted to increase the performance and decrease a production cost of core materials in fuel cell technology. The utilization of reinforced composite membranes as electrolytes in the polymer electrolyte membrane fuel cells can reduce the use of high cost perfluorosulfonic acid (PFSA), mitigate the cell impedance, and improve the dimensional stability as well as the interfacial stability, giving rise to achieve both an improved performance and a reduction of production costs of the fuel cell devices. In this study, we investigate the effects of physical characteristics and cell performances according to the various ionomer solvents in the solution based manufacturing process of reinforced composite electrolyte membrane.