• Journal of the Korean Electrochemical Society
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• v.15 no.3
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• pp.190-197
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• 2012

We employed the vinyl ethylene carbonate (VEC) as an electrolyte additive and investigated the effect of the electrolyte additive on the electrochemical performance in hybrid capacitor. The activated carbon was adopted as cathode material, and the $Li_4Ti_5O_{12}$ oxide was used as anode material. The electrolyte was prepared with the $LiPF_6$ salt in the mixed solvent of ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate(EMC). We evaluated the electrochemical performance of the hybrid capacitor with increasing the amount of the VEC electrolyte additive, which is known as the remover of oxygen functional group and the stabilizer of the electrode by reducing the surface of electrode, and obtained the superior performance data especially at the addition of the VEC electrolyte additive of around 0.7 vol%. On the contrary, the addition of the VEC more than 0.7 vol% in the electrolyte leads to the degradation in electrochemical performance of hybrid capacitor, suggesting the increase of the side reaction from the excessive VEC additive. X-ray photoelectron spectroscopy (XPS) revealed that the addition of the VEC suppressed the formation of LiF component, which is known as the insulator, on the surface of electrode. The optimized addition of VEC exhibited the improved capacity retention around 82.7% whereas the bare capacitors without VEC additive showed the 43.2% of capacity retention after 2500 cycling test.

• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.17-21
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• 2017

BACKGROUND: Castor oil and wormseed extract are important active ingredients for biopesticide, and ricinoleic acid in castor oil and three monoterpenes (ascaridole, carvacrol and p-cymene) in wormseed extract are known bioactive substances. However, their stabilities had not been studied, even though the stability was the core property for estimation of shelf-life of biopesticide. Aimed to investigate the thermal stabilities of the bioactive substances in castor oil and wormseed extracts. METHODS AND RESULTS: The contents of ricinoleic acid and three monoterpenes (ascaridole, carvacrol and p-cymene) were analyzed by gas chromatography (GC). The thermal stabilities of the bioactive substance were measured at $0^{\circ}C$, $23^{\circ}C$, $30^{\circ}C$, $40^{\circ}C$, $45^{\circ}C$ and $54^{\circ}C$ for 84 d. The half-lives of ricinoleic acid in biopesticides was ranged from 28.9 d to 57.8 d at $30^{\circ}C$, and the stability of pure castor oil were located in the range ($t_{1/2}$=46.2d for Indian product and 27.7 d for Korean product) at the same temperature. The half-lives of the total monoterpenes in biopesticides were ranged from 3.9 d to 27.7 d at $30^{\circ}C$. Among the monoterpenes, the stability ascaridole and p-cymene were decreased in acidic condition. All the bioactive substances showed similar stability on the different thermal conditions. CONCLUSION:The half-lives of most bioactive substance from castor oil and wormseed extracts were less than 100 d. To increase the stability of bioactive substance in biopesticide, stabilizing additives like antioxidant and oxygen remover should be considered to extend of the shelf-life.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.3
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• pp.11-17
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• 2013

With high social demands for the diverse utilizations of forest lands, the illegal forest land use changes have increased. We studied change detection technique to detect changes in forest land use using an object-oriented segmentation of RED bands differencing in multi-temporal aerial photographs. The new object-oriented segmentation method consists of the 5 steps, "Image Composite - Segmentation - Reshaping - Noise Remover - Change Detection". The method enabled extraction of deforested objects by selecting a suitable threshold to determine whether the objects was divided or merged, based on the relations between the objects, spectral characteristics and contextual information from multi-temporal aerial photographs. The results found that the object-oriented segmentation method detected 12% of changes in forest land use, with 96% of the average detection accuracy compared by visual interpretation. Therefore this research showed that the spatial data by the object-oriented segmentation method can be complementary to the one by a visual interpretation method, and proved the possibility of automatically detecting and extracting changes in forest land use from multi-temporal aerial photographs.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.214-218
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• 2014

We introduce a technical equipment of GATe (Green (algae)-tide) water combine developed by K-water. The GATe water combine consists of five modules: main body and buoyant, transfer hopper, screen conveyer, sludge remover, and separator of algae and waste. Also a sprinkler, as the pre-treatment step if necessary, is equipped to the device to spread out environmental-friendly algaecide under the circumstance that the level of algal bloom does not reach to the scum-forming condition. The overall module system of this device is very simple. Based on the field test, the device covers surface area of ca. $500,000m^2day^{-1}$ during the period from May to July, and treats water volume as much as $500,000m^3day^{-1}$ in spite of some variation depending on the water quality condition. The removal efficiency of the device appeared to be over 90%. In addition, the operating duration of the device was able to expand to cover the period between March and November. We expect this new technology can be used to solve algal bloom problems in drinking water resource and public water area.

• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.575-580
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• 2020

In this study, we simulated an amine regeneration process with heat-stable salts removal unit. We derived the optimal operating conditions considering the flow rate of waste, the removal rate of heat-stable salts, and the loss rate of MDEA (methyl diethanolamine). In the amine regeneration process that absorbs and removes acid gas, heat-stable salt impairs the absorption efficiency of process equipment and amine solution. An ion exchange resin method is to remove heat-stable salts through neutralization by using a strong base solution such as NaOH. The acid gas removal process was established using the Radfrac model, and the equilibrium constant of the reaction was calculated using Gibbs free energy. The removed amine solution is separated and flows to the heat-stable salts remover which is modeled by using the Rstoic model with neutralization reaction. Actual operation data and simulation results were compared and verified, and also a case study was conducted by adjusting the inflow mass of removal unit followed by suggesting optimal conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.378-385
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• 2021

The production of plum jangachi requires the cleaning of plums, immersion in saltwater, separation of seed and pulp, removal of impurities, and addition of sugar. In most farms, the separation of plum seed and pulp is carried out manually, requiring considerable labor, which is why plum jangachi is expensive. To solve this problem, this study designed and manufactured automatic, semi-automatic plum seed and pulp separators. During the design process, the characteristics were compared, and the machine power was determined through on-site test after manufacture. As a result, automatic machines used plums 180° arrayed and six reverse-edged blades, semi-automated plums 180° arrayed, and six blades, each with a 68% and 57% pulp recovery rate and a machine power of 80 kg/h and 62 kg/h respectively. Overall, the mechanization of plum processed food will reduce labor and increase the market value of plums compared to the previous method.

• Korea Science and Art Forum
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• v.30
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• pp.251-261
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• 2017

Metal is a material that has exerted a lot of influence on the development of human cultures, and has closely connected with our life from the past to the present. Types of metal we have used from the prehistoric times are varied, and iron relics take the largest percentage of metal relics excavated in our country. The biggest threat to the existence of iron relics ranging from excavated relics to the ones that are transmitted is the process of corrosion, and physical removal has been used the most for removing corroded oxides. For details for removal of corrosion oxides, this thesis aimed to research on the chemical corrosion oxides remover that protects parent material of iron relics but treats corrosion oxides only. For safe and effective removal of corrosion oxides of iron relics, this study was conducted aiming at finding the possibility of and optimized composition for removal of iron relics corrosion oxides by manufacturing new acid, alkaline and neutral oxides removers and changing their composition variously, exploring the possibility by applying the agents to modern relics. The results of this study are as follows: First, the acid solution removed only some part of corrosive substance oxidized on the surface of metal specimen. Second, the application of each of alkaline and neutral solution resulted in remaining black-colored corrosive substance, but it was removed when the quantity of the solution and the duration of application are increased. Third, All the three solutions did not cause any damage to parent material in the course of application, and showed the result that they are capable of removing unstable oxide layer while protecting parent material and stable corrosive layer as the solutions would be able to deal with situation by a relic only through the control of concentration of solution and duration of application.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.231-239
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• 2013

Purpose: To design and fabricate the auto pattern maker for the development. Methods: we got the necessary data, needed in design, by using CAD. Based on the these data, we fabricated the trial product for the development of the auto pattern maker. Results: The auto pattern maker were composed with combinations of many elements; pattern making assembly, control panel, frame attachment and prober unit. The pattern making assembly was comprised of the cutter, the pattern holder, pattern remover and silence cover which could minimize the sound during the cutting process. The control panel was designed to be connected and operated with the main printed circuit board. The prober could get the eye shape data by scanning of 1.8 degrees around the groove of the frame through the encoding data according to the address. After starting, scanning was carried out in two passes, i.e. one right-handed and one left-handed. Communication connector could send the eye shape data from auto pattern maker to outer system with the RS232C transmission system. By using the one-way analysis of variance, we got the error rate of cut pattern size for ${\Phi}22mm$, ${\Phi}55mm$ and ${\Phi}62mm$. Because F-value was 0.510 and p-value was 0.601, no statistically significant differences were found. Also, the mean cutting error of the auto pattern maker was 0.0274 mm. Conclusions: we could succeed in making the trial product by applying it to the development of the auto pattern maker. The role of this auto pattern maker is to find a exact required size of lens to fit the frame by measuring the frame. The acquired data are transferred to outer system for grinding and finishing with patternless process. Also, the trial product can produce pattern to fit the frame. Therefore, it was confidently expected that the optometrists could handily produce pattern to fit the frame with this trial product and dispense the ophthalmic lens because of its efficiency and convenience compared to the past.