• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.94-131
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• 2007

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2004 and 2005 has been done. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD and flow visualization(PIV, PTV and LDV methods) technologies were widely applied for developing facilities and their systems. (2) The research trends of the previous two yews are surveyed as groups of natural convection, forced convection, electronic cooling, heat transfer enhancement, frosting and defrosting, thermal properties, etc. New research topics introduced include natural convection heat transfer enhancement using nanofluid, supercritical cooling performance or oil miscibility of $CO_2$, enthalpy heat exchanger for heat recovery, heat transfer enhancement in a plate heat exchanger using fluid resonance. (3) The literature for the last two years($2004{\sim}2005$) is reviewed in the areas of heat pump, ice and water storage, cycle analysis and reused energy including geothermal, solar and unused energy). The research on cycle analysis and experiments for $CO_2$ was extensively carried out to replace the Ozone depleting and global warming refrigerants such as HFC and HCFC refrigerants. From the year of 2005, the Gas Engine Heat Pump(GHP) has been paid attention from the viewpoint of the gas cooling application. The heat pipe was focused on the performance improvement by the parametric analysis and the heat recovery applications. The storage systems were studied on the performance enhancement of the storage tank and cost analysis for heating and cooling applications. In the area of unused energy, the hybrid systems were extensively introduced and the life cycle cost analysis(LCCA) for the unused energy systems was also intensively carried out. (4) Recent studies of various refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and of alternative refrigerants including carbon dioxide. Efficiency of various compressors and expansion devices are also dealt with for better modeling and, in particular, performance improvement. Thermoelectric module and cooling systems are analyzed theoretically and experimentally. (5) According to the review of recent studies on ventilation systems, an appropriate ventilation systems including machenical and natural are required to satisfied the level of IAQ. Also, an recent studies on air-conditioning and absorption refrigeration systems, it has mainly focused on distribution and dehumidification of indoor air to improve the performance were carried out. (6) Based on a review of recent studies on indoor environment and building service systems, it is noticed that research issues have mainly focused on optimal thermal comfort, improvement of indoor air Quality and many innovative systems such as air-barrier type perimeter-less system with UFAC, radiant floor heating and cooling system and etc. New approaches are highlighted for improving indoor environmental condition as well as minimizing energy consumption, various activities of building control and operation strategy and energy performance analysis for economic evaluation.

• Food Science and Preservation
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• v.16 no.5
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• pp.612-617
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• 2009

Kimchi is a traditional pickled food using Korean Chinese cabbage(Brassica campestris var. pekinensis) and also containing phytochemicals, glucosinolates. This study was carried out to investigate the changes in the total glucosinolates levels of Kimchi using Korean Chinese cabbage of harvest time(June-July, August-September, October-November, December-April, May) according to storage temperature(4, 10, $15^{\circ}C$) and storage duration(0, 1, 3, 5, 7, 10, 14, 21 and 28 day). For determination of glucosinolates, 50g of Baechu kimchi was used for analytical sample preparation provided with an anion exchanges column and measured by UV-visible Spectrophotometer. The highest contents of water occurred at August-September during fermentation. At 15, 10, $4^{\circ}C$, the pH in all of seasonal variation of Baechu kimchi declined, especially from 0 to 3 days at $15^{\circ}C$, from 0 to 7 days at $10^{\circ}C$ and from 0 to 14 days at $4^{\circ}C$. At that storage, the total glucosinolates levels in all of seasonal variation of Kimchi declined in storage temperature. Baechu kimchi at August-September showed the highest total glucosinolates levels. Also total glucosinolates levels decreased as storage period increased. Baechu kimchi fermented at $15^{\circ}C$ for 7days decreased rapidly and reached to the lowest at the 1day(ranged from $10.3{\pm}0.70$ to $23.4{\pm}0.37{\mu}mol/g$ dry weight). At $10^{\circ}C$ for 14days were ranged from $12.9{\pm}0.29$ to $33.7{\pm}1.81{\mu}mol/g$ dry weight before fermentation and decreased rapidly at the 3day(ranged from $9.5{\pm}0.54$ to $20.5{\pm}0.61{\mu}mol/g$ dry weight). Total glucosinolates levels of Baechu kimchi fermented at $4^{\circ}C$ for 28days decreased rapidly during 7day(ranged from $9.9{\pm}0.78$ to $21.1{\pm}0.96{\mu}mol/g$ dry weight) and then slowly decreased. Therefore the total glucosinolates levels decreased during storage time and depended on harvest time and storage conditions of Kimchi.

• Food Science and Preservation
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• v.24 no.1
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• pp.13-20
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• 2017

This study was carried out to investigate the quality characteristics of fried fish paste prepared with different amounts of squeezed Aronia melanocarpa juice. Squeezed Aronia melanocarpa juice (AMJ) was incorporated into fish paste at different levels (containing 2, 7, and 12 g of Aronia melanocarpa juice in 2 AMJ, 7 AMJ, and 12 AMJ, respectively) based on the total weight of water. Sugar contents and total acidity increased with increasing AMJ content. With increasing amounts of AMJ in fried fish paste, L value inside and on the surface decreased, a value increased, and b value inside decreased, whereas b value on the surface increased. pH decreased with increasing levels of AMJ. As the result of textural properties, folding test in all samples showed that AA means good flexibility. The strength, hardness, and chewiness of fried fish paste with AMJ increased while cohesiveness was not significantly different. Total polyphenol contents increased with higher levels of AMJ. DPPH radical scavenging activity was significantly higher than those of the control. In the sensory evaluation, fried fish paste containing 7 AMJ received the highest score than both the control and other samples.

• Korean Journal of Plant Resources
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• v.25 no.1
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• pp.132-141
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• 2012

This study was carried out to test seed germination responses to temperatures and pre-treatments in Hippophae rhamnoides, which has many abilities in antioxidant activity, soil improvement and erosion control. H. rhamnoides seeds were placed at 10, 15, 20, 25, 30 and $35^{\circ}C$ under light condition. As the results, germination percentage (GP) was the highest at 15 and $20^{\circ}C$, and mean germination time (MGT), germination rate (GR) and germination value (GV) were the highest at $25^{\circ}C$. Quadratic and linear regression model were used to determine the cardinal temperatures such as base ($T_b$), maximum ($T_m$) and optimum ($T_o$) temperature for germination. In quadratic regression model using PG, $T_b$, $T_m$ and $T_o$ was estimated as 0.6, 36.4 and $18.5^{\circ}C$, respectively, and temperature range for germination was $35.8^{\circ}C$. In linear regression model using GR, $T_b$, $T_m$ and $T_o$ was estimated as 8.3, 35.4 and $25.3^{\circ}C$, respectively, and temperature range for germination was $27.2^{\circ}C$. Germination properties were investigated after H. rhamnoides seeds were treated by prechilling (1, 2, 4, 6 and 8 weeks), stratification (2, 4, 6 and 8 weeks), solid matrix priming (seed : carrier : water = 5 : 1 : 7, 8, 9 and 10), osmo-priming (-0.25, -0.5, -1.0 and -1.5 MPa) and calcium chloride ($CaCl_2$) -priming (100, 200, 300 and 400 mM). The highest GP was observed in $CaCl_2$ 300 and 400 mM treatments, and MGT was the shortest in stratification 6 and 8 weeks treatments. GR and GV were the highest and GP was the second highest when seeds were prechilled for 1 and 2 weeks. Consequently, prechilling 1 or 2 weeks treatment was considered as the appropriate method when we contemplate qualitative and quantitative effects in seedling production.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.60-71
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• 2014

This study was conducted to identify the potential of rape stalk as a raw material for biorefinery process of rape flower. At first, rape stalk (RS) was immersed in distilled water (DW), acetic acid (AA), oxalic acid (OA), sulfuric acid (SA) and sodium hydroxide (SH) solutions, and the content of reducing sugars liberated from immersed RS was analyzed. Glucose, xylose, arabinose and sucrose were detected varying with the immersion type. In particular, 1% AA-immersion of RS for 72 hr was the most effective conditions to liberate glucose from RS. Secondly, the RS residues were used for elementary analysis and fabrication of fuel pellets. In addition to the solution type, concentration of immersion solutions (0%, 1%, 2%) and immersion time (24, 72, 120 hr) were used as experimental factors. The contents of nitrogen, sulfur and chlorine reduced effectively through the immersion of RS in DW, AA and OA solutions. For properties of RS-based pellets, bulk density and higher heating value of RS-based pellets greatly increased with the immersion of RS, and the qualities were much higher than those of the A-grade pellet of the EN standards. Ash content decreased remarkably through the immersion of RS, and was satisfied with the A-grade pellet standard. Durability was negatively affected by the immersion of RS, and did not reached to B-grade of the EN standard. In conclusion, acid immersion of RS can be a pretreatment method for the production of fuel pellet and bioethanol, but use of the immersed RS for the production of high-quality pellets might be restricted due to low durability of immersed-RS pellets. Therefore, further studies, such as investigation of detailed immersion conditions, fabrication of mixed pellets with wooden materials and addition of binders, are needed to resolve the problems.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1381-1387
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• 1998

Laminated films were prepared by casting corn-zein and fatty acid mixed solutions onto ${\kappa}-carrageenan$ films, and the effect of various fatty acids with different concentrations on the film properties such as water vapor permeabilities (WVP), tensile strength (TS) and elongation was investigated. WVP of the film decreased as concentration of fatty acids increased, and the lowest WVP value $(0.497\;ng\;m/m^2\;s\;Pa)$ was achieved with laminated films containing 30% lauric acid/corn-zein. The TS of laminated edible film seemed to decrease as the concentration of fatty acids increased, and TS of the laminated film was the highest (36.21 MPa) when the film contained 10% oleic acid. Weight loss of the minced mackerels packaged with corn-zein/carrageenan film which did not contain fatty acid was 11.7%, but weight losses of the samples packaged with oleic acid and lauric acid were 6.97% and 0.81%, respectively, after 30 days storage at $-20^{\circ}C$. The laminated films had an effect on preventing oxidation of the minced mackerels during storage because of high oxygen barrier property of the film. All of the minced mackerels packaged with the laminated films greatly reduced the peroxide value (POV) compared with unpackaged minced mackerels during storage. Also, thiobarbituric acid (TBA) values of the minced mackerels packaged with the laminated films were lower than that of unpackaged minced mackerels during storage.

• Journal of Embryo Transfer
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• v.32 no.1
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• pp.1-8
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• 2017

Cryopreservation of germ cells from genetically proven animals could be a source of restoration tools from the risk of extinction or disappearance of wanted characteristics. Using frozen semen, the genetic gains of Korean native cattle have been increased greatly for 70 years. The preservation of genetic resources as a form of frozen semen straw has limited availability due to the numbers. To circumvent this weakness of frozen semen, we tested two re-freezing methods with different initial thawing temperatures using frozen Korean proven semen and rare breed semen from albino, black and chikso breeders. It has been known that human sperm could resist to cryo-damages by repeated freeze-thaw cycles, but not for Korean proven bulls number (KPN) or for rare breeds. Total 7 frozen semem from brindled(2), black(1), Korean Albino(2) and KPN(1) bulls were used for our research. After thawing straws under $5^{\circ}C/2min$ or $37^{\circ}C/40sec$ with low temperature water bath and thermo jug, spermatozoa were re-diluted with triladyl diluents after first thawing and re-frozen. Sperm motilities were compared between animals and treated groups after re-thawing. Mean values of motility and viability of refrozen/thawed sperm for expansion of the number of straws were significantly higher in $5^{\circ}C$ than in $37^{\circ}C$ (P < 0.05). However, the activity of viable sperm thawed at $5^{\circ}C$ was significantly decreased before refreezing. It is estimated that re-freezing of frozen semen from rare Korean native cattle is possible with resistant properties of survived spermatozoa.

• Korean Journal of Environmental Agriculture
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• v.23 no.4
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• pp.211-219
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• 2004

Three sludge types from pharmaceutical byproducts and one sludge type from cosmetic waste-water sludge as raw materials of compost were used in a field based concrete pot ($4\;m^2$, $2\;m{\times}2\;m$) for investigating damage of red pepper cultivation. These sludges and pig manure (1 Mg/10a, dry basis) were incorporated into the upper of clay loam soil prior to transplanting with red pepper. Changes in concentration and properties of heavy metal for both of soil and plant were investigated 4 times during of red pepper growth. Plant height and stem diameter of red pepper in sludge treatments except to Pharmaceutical sludge 3 were poor than those of NPK treatment. This result were regarded as an effect of incompleted decomposition sludge which has a lot of organic matter concentration. Amount of total As was increased rapidly Jul. 8. in soil, total Zn Cu Pb Cd were in harvest time, and 1 N-HCl extractable Zn Cu Pb Cd As were in harvest at middle stage and then decreased. Amounts of nitrogen in plant (leaf and stem) were high in Phamaceutical Sludge 1 and fig Manure treatment in early and middle stage because of organic matter and nitrogen concentrations and characteristics. Amounts of Zn, Pb, and Ni in leaf and amount of Zn and Pb in stem were increased in harvest time so that we need to have a concern in detail. Total yield of red pepper was Pig Manure > Phamaceutical Sludge 3 > Phamaceutical Sludge 1 > NPK > Phamaceutical Sludge 2 and Cosmetic Sludge treatment was decreased considerably to compare to others. Amounts of Zn and Cu in green and red pepper in harvest time were higher than the other heavy metals. Finally these results can use to utilize that finding damage on crop for authorization and suitability estimation of raw material of compost.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.60-68
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• 2018

A cold-active and alkaline serine protease (Pro21717) was partially purified from the Antarctic marine bacterium Pseudoalteromonas arctica PAMC 21717. On a zymogram gel containing skim milk, Pro21717 produced two distinct clear-zones of approximately 37 kDa (low intensity) and 74 kDa (high intensity). These were found to have identical N-terminal sequences, suggesting they arose from an identical precursor and that the 37 kDa protease might homodimerize to the more active 74 kDa form of the protein. Pro21717 displayed proteolytic activity at $0-40^{\circ}C$ (optimal temperature of $40^{\circ}C$) and maintained this activity at pH 5.0-10.0 (optimal pH of 9.0). Notably, relative activities of 30% and 45% were observed at $0^{\circ}C$ and $10^{\circ}C$, respectively, in comparison to the 100% activity observed at $40^{\circ}C$, and this enzyme showed a broad substrate range against synthetic peptides with a preference for proline in the cleavage reaction. Pro21717 activity was enhanced by $Cu^{2+}$ and remained stable in the presence of detergent surfactants (linear alkylbenzene sulfonate and sodium dodecyl sulfate) and other chemical components ($Na_2SO_4$ and metal ions, such as $Ba^{2+}$, $Mg^{2+}$, $Ca^{2+}$, $Zn^{2+}$, $Fe^{2+}$, $K^+$, and $Na^{2+}$), which are often included in commercial detergent formulations. These data indicate that the psychrophilic Pro21717 has properties comparable to the well-characterized mesophilic subtilisin Carlsberg, which is commercially produced by Novozymes as the trademark Alcalase. Thus it has the potential to be used as a new additive enzyme in laundry detergents that must work well in cold tap water below $15^{\circ}C$.

• Journal of fish pathology
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• v.31 no.1
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• pp.23-34
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• 2018

The pharmacokinetic properties of cefadroxil (CDX) were studied after oral administration for 7 days to cultured olive flounders (average 660 g), Paralichthys olivaceus. For examination of pharmaco-kinetic profiles, CDX of 45 to 225 mg/kg body weight was administered at two different water temperatures, $13{\pm}3^{\circ}C$ or $22{\pm}3^{\circ}C$. CDX concentrations were determined in muscle, plasma, gastrointestinal tract, hematopoietic organs and liver by HPLC-MS/MS. Muscle samples were taken at 0.25, 0.5, 1, 3, 7, 14 and 28 days post dose, whereas plasma, gastrointestinal tract, hematopoietic organs and liver concentrations were measured at 1, 3, 7, 14 and 28 days post-dosing. The kinetic profiles of $C_{max}$, $T_{max}$, $T_{1/2}$ of CDX were analyzed by fitting to a non-compartmental model with PKSolver program. The following pharmacokinetic parameters were obtained with oral administration of 45 and 225 mg/kg at 13 and $22^{\circ}C$ in muscle, plasma, gastrointestinal tract, hematopoietic organs and liver, respectively: $C_{max}$ (maximum tissue concentration)=$985.98-5,032.86{\mu}g/kg$, $5,670.99-38,922.23{\mu}g/l$, $2,457.27-10,192.78{\mu}g/kg$, $886.04-3,070.87{\mu}g/kg$ and $1,188.15-3,814.33{\mu}g/kg$; $T_{max}$ (time for maximum concentration)= every 1 day; $MRT_{0-{\infty}}$ (mean residence time)= 1.51-4.74, 2.12-3.06, 4.25-13.18, 1.37-18.66 and 1.78-29.76 days; $T_{1/2}$ (half-life)= 1.08-3.47, 1.14-5.42, 3.56-10.99, 1.17-14.93 and 1.25-28.55 days.