• Journal of Energy Engineering
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• v.20 no.1
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• pp.26-29
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• 2011

A promising alternative technology is the potential use of ice slurries as a secondary refrigerant in conventional cooling process. Ice slurries behave almost like a liquid and can be pumped through pipes although the energy capacity of ice slurries per unit volume is considerably higher than that for chilled water or brine due to the latent heat capacity of the ice particles. To give the basic data for the design of cooling systems using ice slurries, experimental study has been conducted to find out the performance of the cooling coil of show-case with ice slurries. Despite the fact that ice slurries entering the cooling coil had at least $5^{\circ}C$ higher temperature than that of R22, it was still capable of providing a similar cooling performance than that obtained with R22.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.6
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• pp.70-78
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• 2012

The Annals of Joseon Dynasty, which recorded governmental affairs for 472 years (AD 1392-1863) during the Joseon dynasty is an representative paper cultural heritage in Korea. Being recognised their authenticity and values they were designated as the No 151 national treasure of Korea in 1973 and registered as 'The Memories of the World' by UNESCO in 1997. Unusually, some volumes of the Annals were treated by beeswax for the permanent preservation. However, the examinations on the deterioration of the beeswax-treated volumes had been exposed the serious damage than the untreated volumes. In particular, the larger amount of beeswax were worst in deterioration condition. In order to solve these problems, NRICH(National Research Institute of Cultural Heritage) of Korea launched the investigation study for the conservation of beeswax-treated volumes of the Annals. Now then, the five study areas have been set up; 1) to understand the damaged condition of the Annals; 2) to analyse the raw materials and production techniques; 3) to test the degradation degree using the duplication samples for understanding the aging factors and mechanism; 4) to develop the conservation techniques through dewaxing and thereafter strengthening the base paper of Hanji; 5) to develop the long-term storage technique using inert gases. On the basis of outcomes from this study, NRICH will plan to establish the systematic conservation and management plan for the beeswax-treated volumes of the Annals in future.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.171-180
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• 2013

Metal organic frameworks (MOFs) are a class of crystalline organic-inorganic hybrid compounds formed by coordination of metal clusters or ions with organic linkers. MOFs have recently attracted intense research interest due to their permanent porous structures, large surface areas and pore volume, high-dispersed metal species, and potential applications in gas adsorption, separation, and catalysis. $CO_2$ adsorption in MOFs has been investigated in two areas of $CO_2$ storage at high pressures and $CO_2$ adsorption at atmospheric pressure conditions. In this short review, $CO_2$ adsorption/separation results using MOFs conducted in our laboratory was explained in terms of four contributing effects; (1) coordinatively unsaturated open metal sites, (2) functionalization, (3) interpenetration/catenation, and (4) ion-exchange. Zeolitic imidazolate frameworks (ZIFs) and covalent organic frameworks (COFs) were also considered as a candidate material.

• Environmental Engineering Research
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• v.23 no.1
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• pp.36-45
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• 2018

The phosphogypsum (PG) is a byproduct of the phosphate fertilizers manufacture. The world production estimated to 200 million tons per year induces environmental threats and storage problems, which requires strict policies to limit pollution and encourage its valorization. This paper presents a purification process of the crude PG including treatment with a diluted sulfuric acid, floatation, filtration and washing. The purified PG is used to produce plaster. The process optimization was conducted using a full factorial design. The significant factors considered in the experimental study are temperature ($X_1$), volume of sulfuric acid solution ($X_2$) and PG quantity ($X_3$). The main effects and interaction effects of these factors on the responses of the % $P_2O_5$, % F, Total Organic Carbon (TOC) ($mg{\cdot}kg^{-1}$) and pH were analyzed. The optimum conditions for $X_1$, $X_2$ and $X_3$ were found to be $60^{\circ}C$, 3 L and 1 kg, respectively and the optimized pH values was found to be 6.2. Under these conditions, 60% of $P_2O_5$, 95% of Fluorine and 98% of TOC were removed from PG. The predicted values were found approximately the same as the experimental ones. The plaster produced with purified PG was found to have similar properties to that produced from natural gypsum.

• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.358-365
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• 2016

Removing hazardous materials from water resources is very important for efficient utilization of the resources, and adsorptive removal is regarded as a competitive technology when good adsorbents with high capacity/selectivity are available. Metal-organic framework (MOF), composed of both organic and inorganic (metallic) species, have been tried for various adsorptions because of huge surface area/pore volume, well-defined pore structure, and facile functionalization. In this review, we summarized technologies on adsorptive removal of hazardous organics from water mainly using MOFs as adsorbents. Instead of reporting high adsorption capacity or rate, we summarized mechanisms of interaction between adsorbates (organics) and adsorbents (MOFs) and methods to modify or functionalize MOFs for effective adsorptions. We expect for readers of this review to understand needed characteristics of adsorbents for the adsorptive removal, functionalization of MOFs for effective adsorption and so on. Moreover, they might have an idea on storage and delivery of organics via understanding of the mechanism of adsorption and interaction.

• Korean Journal of Food Science and Technology
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• v.47 no.6
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• pp.687-697
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• 2015

With the shortage of edible fats and oils and depletion of fossil fuels in many countries, microbial lipids is emerging as one of the most promising sources of fats and oils in the global market. Oleaginous microorganisms, also called single cell oils (SCOs), can accumulate lipids more than 25% in the cell volume. Triacylglycerols are the major storage lipids. SCOs offer several advantages for lipid production as follows: SCOs have short life span which would shorten production time, cultivation conditions are not affected by climate and place; the production process is easy to control. There are a number of oleaginous yeasts, molds, and microalgae. Furthermore, the lipid productivity of SCOs can be enhanced through strain improvement and the optimization of cultivation conditions. The new strains developed using recent advanced biotechnical methods showed greatly improved oleaginicity. Further, hydrolysates of lignocellulosic materials can be used as carbon sources for economic production of SCO.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.8
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• pp.404-410
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• 2006

Toward the practical applications, on operation of conduction-cooled HTS SMES at temperatures well below 40[K] should be investigated, in order to take advantage of a greater critical current density of HTS and considerably reduce the size and weight of the system. In order to take advantage of a greater critical current density of high temperature superconducting (HTS) and considerably reduce the size and weight of the system, conduction-cooled HTS superconducting magnetic energy storage (SMES) at temperatures well below 40[K] should be investigated. This work focuses on the breakdown and flashover phenomenology of dielectrics exposed in air and/or vacuum for temperatures ranging from room temperature to cryogenic temperature. Firstly, we summarize the insulation factors of the magnet for the conduction cooled HTS SMES. And Secondly a surface flashover as well as volume breakdown in air and/or vacuum with two kind insulators has been investigated. Finally, we will discuss applications for the HTS SMES including aging studies on model coils exposed in vacuum at cryogenic temperature. The commercial application of many conduction-cooled HTS magnets, however, requires refrigeration at temperatures below 40[K], in order to take advantage of a greater critical current density of HTS and reduce considerably the size and weight of the system. The magnet is driven in vacuum condition. The need to reduce the size and weight of the system has led to the consideration of the vacuum as insulating media. We are studying on the insulation factors of the magnet for HTS SMES. And we experiment the spacer configure effect in the dielectric flashover characteristics. From the results, we confirm that our research established basic information in the insulation design of the magnet.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1170-1176
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• 2007

The conventional urodynamic monitoring is fulfilled by artificially filling a bladder with saline. Generally. it is difficult to evaluate the physiological functions of the storage and voiding of a bladder. With this aim, we constructed an ambulatory urodynamic monitoring (AUM) system and proposed a novel method estimating abdominal pressure by measuring bio-impedance variations. Our system was clinically evaluated for 10 patients. It turned out to be that as the intensity of the abdomen contraction increased, the amplitude of bio-impedance signal and the RMS value of EMG increased more as compared to those who observed during the rest mode. Also, we determined the optimum electrode pair for estimating the abdominal pressure using bio-impedance method and consequently compared with the conventional methods. Because impedance changes differ from a weight, a height, contractile force, volume of muscle and blood other or whatever of individuals, it was quantified in terms of impedance change, correlation coefficient and SNR Our results showed the optimum electrode pair (1,9) which could detect impedance changes due to the increase of the intensity in the abdominal pressure. The correlation coefficient and quadratic function between the RMS values of EMG and the impedance changes were 0.87 and $y=0.0014x^2+0.0620x+0.6958$, respectively. Thus, our system demonstrated that the abdominal pressure could be measured noninvasively and conveniently by simply estimating bio-impedance values. We propose that this optimum electrode configuration would be useful for the future studies involving the handy measurements of abdominal pressure with our suggested ambulatory urodynamics monitoring system.

• Food Science and Preservation
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• v.12 no.3
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• pp.292-298
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• 2005

Kochujang(Korean red pepper paste) of 600 g was fermented in the different types of vessels (glass, polypropylene(PP), polyethylene terephthalate(PET), stainless steel and Korean porcelain called onggi) with 627 mL of volume during 4 months. The quality changes were monitored for physical, chemical and microbiological attributes. Onggi which had high porosity in the micro-structure provided kochujang with higher microbial counts of aerobic bacteria, lactic acid bacteria and yeasts than those of the other containers. Compared to kochujang fermented in the other containers, kochujang in Onggi showed higher protease activity, amino type nitrogen, and free amino acid content. The kochujang in Onggi also attained higher acidity, lower pH and higher reducing sugar concentration than those in the other containers. All changes were completed 2 or 3 months. Onggi showed water loss and salt increase of the kochujang comparable to those in the other vessels, which was from gradual clogging of the micropores during storage. All physical, chemical and microbiological changes made the kochujang in Onggi attain the sensory quality significantly better than those fermented in the other vessels.

• Korean journal of food and cookery science
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• v.13 no.4
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• pp.492-499
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• 1997

The effect of oxidants, gluten and gums on breadmaking quality of wheat-purple sweet potato(Ipomoea batatas) composite flour were studied. Alveograph tests of doughs showed that all additives increased the P, L and W values. Of these additives, L-Ascorbic acid, gluten, carboxy methyl cellulose have a significant effect on alveogram indexes. SEM showed that the dough added with additives changed some what in appearance when compared with the control. When oxidants was added, the doughs discontinuous gluten film were observed. No significant differences ,were evident in bread crumb color among the additives. And textural characteristics of bread crumb were influened by adding additives. Breads containing additives showed an increase in max weight, strength and hardness and a decrease in springness and cohesiveness. Average enthalpy values for all bread crumb after 7days increased with storage time. However, addition of additives decrease the rate of staling slightly more than that of the control. Addition of L-Ascorbic acid, L-Cystine, carboxy methyl cellulose and hydroxy propyl methyl cellulose increased the loaf volume significantly, and with except potassium bromate bread scores were acceptable.