• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.4
• /
• pp.125-132
• /
• 2012

Urea-SCR system, which converts nitrogen oxides to nitrogen and water in the presence of a reducing agent, usually AdBlue urea solution, is known as one of the powerful NOx reduction systems for mobile as well as stationary applications. For its consistent and reliable operation in mobile applications, such various problems as transient injection, ammonia slip, and freezing in cold weather have to be resolved. In this work, therefore, numerical study on three-dimensional unsteady heating problems were analyzed to understand the melting and heat transfer characteristics such as urea liquid volume fraction, temperature profiles and generated natural convection behavior in urea solution by using the commercial software Fluent 6.3. After validating by comparing numerical and experimental data with pure gallium melting phenomena, numerical experiment for urea melting is conducted with three different coolant heating models named CH1, 2, and 3, respectively. Finally, it can be found that the CH3 model, in which more coolant is concentrated on the lower part of the urea tank, has relatively better melting capability than others in terms of urea quantity of $1{\ell}$ for start-up schedule.

• Journal of Embryo Transfer
• /
• v.26 no.2
• /
• pp.117-122
• /
• 2011

In this study, we examined the effectiveness of in vitro fertilization of porcine immature oocytes on the embryo development of blastocysts or hatched blastocysts and the number of cells according to the in vitro fertilization conditions. In the in vitro fertilization of in vitro matured porcine oocytes, there were no significant differences between treatment groups regarding fertilization rate, blastocyst rate, and embryo development of hatched blastocysts according to the storage periods of liquid sperm of 24, 48, and 72 hours. The embryo development rate of hatched blastocysts after the fertilization according to different spermatozoa concentrations ($0.4{\times}10^5$, $1.2{\times}10^5$, and $3.6{\times}10^5$ cells/ml) showed the highest rate in the group with a spermatozoa concentration of $1.2{\times}10^5$ cells/ml; in particular, this rate was significantly higher than that in the $0.4{\times}10^5$ cells/ml group (p<0.05). The total number of blastocysts cells as well as trophectoderms (TE) that developed in each treatment group were also significantly higher in the $1.2{\times}10^5$ cells/ml group than in any other groups (p<0.05). In contrast, the embryo development rate of blastocysts according to different co-incubation periods of sperm and oocyte (1, 3, and 6 hr) was high in the 6-hour group; in particular, the rate was significantly higher than that of the I-hour group (p<0.05). Furthermore, the total number of oocytes cells and TEs that developed was significantly higher in the 6-hour group than any other group (p<0.05). In this study, the most effective treatment conditions for porcine embryo development and high cell number were found to be as follows: a sperm storage period of less than 72 hours, a spermatozoa concentration of $1.2{\times}10^5$ cells/ml, and a 6-hour co-incubation period for sperm and ooocyte.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.8
• /
• pp.6-14
• /
• 2006

This paper is a study about a proper method of plasma generation to cleaning method and a high frequency power equipment circuit to generation of plasma that used cleaning of chamber for TFT-LCD PECVD. The high density plasma required for cleaning causes a possibility of high density plasma more than $1{\times}10^{11}[EA/cm^3]$. It apply a ferrite core of ferromagnetic body to a existing ICP form. In case of power transfer equipment on 400[kHz] high frequency to generation of plasma it makes certain a stable switching operation in condition of plasma through using a inverter form for general purpose HB. And it demonstrates the performance of power transfer equipment using methods of measurement which use a transformer of series combination the density of plasma and the rate of dissolution of $NF_3$ in condition of $A_r\;and\;NF_3$.

• Microbiology and Biotechnology Letters
• /
• v.14 no.6
• /
• pp.455-460
• /
• 1986

Dane particle was prepared from the plasma of chronic HBsAg carrier with high levels of HBsAg activity. DNA extracted front Dane particle core after a DNA polymerase reaction with $\alpha$-($^{32}$P) dNTP, was identified as HBV DNA by liquid scintillation counter and agarose gel electrophoresis-G.M. counting. To produce Hepatitis B surface antigen for use as a vaccine against Hepatitis B virus infection, yeast strains harboring recombinant plasmid with Apase promoter was used. Recombinant plasmid was construced from pHBV 130 and pAN 82, transformed into E coli, and then transferred into yeast strains. HBsAg was produced by derepression in Burkholder minimal medium with controlled inorganic phosphate concentration. The kinetics of HBsAg production was also investigated. Total HBsAg activity increased rapidly between 3 and 6 hours after transfer to phosphate-free medium and reached a maximum at around 9th hour. The transfer into phosphate-free medium after 6 hours in high phosphate cell growth medium gave maximum activity.

• Korean Journal of Soil Science and Fertilizer
• /
• v.49 no.6
• /
• pp.651-654
• /
• 2016

A number of accidents relating to highly toxic hydrogen fluoride (HF) or hydrofluoric acid (HA) release have occurred over fast few decades in Korea. Thus, this study was conducted to investigate the fluoride (F) concentrations in paddy soil and brown rice from 2 different areas where the soils were exposed to HF and HA. In the first case, the HF leakage accident that occurred in 2012 affected the surrounding soils and crops and consequently, crops (rice) affected by HF were unavailable for forage even though F did not accumulate in the soil. For example, at the time of accident, F concentrations in brown rice samples were $33.0-1,395mg\;kg^{-1}$, while F concentrations in soil samples were $155-295mg\;kg^{-1}$ which were less than the Korean standard guideline values of $400mg\;kg^{-1}$. However, after a year, F concentrations in brown rice were observed below the detection limit ($1mg\;kg^{-1}$), although F concentrations in soils were similar with those in 2012. Also, large amounts of wastewater discharges containing HA occurred in 2013 and some agricultural soils exceeded the Korean standard guideline values for F ($400mg\;kg^{-1}$), but soil-plant F transfer was not observed. In conclusion, it was observed that soil to plant transfer of F is unlikely although HF and HA as gas or liquid form can cause direct damage to plants.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.1720-1726
• /
• 2014

(S)-Alanine Racemase Chiral Analogue ((S)-ARCA) was used as an efficient adsorbent for the selective separation of D-amino acids (D-AAs), which are industrially important as chiral building blocks for the synthesis of pharmaceutical intermediates. The organic phase, containing (S)-ARCA adsorbent and phase transfer reagents, such as ionic liquid type molecules (Tetraphenylphosphonium chloride (TPPC), Octyltriphenylphosponium bromide (OTPPBr)), were coated on the surfaces of mesoporous carbon supports. For the immobilization of chiral adsorbents, meso/macroporous monolithic carbon (MMC), having bimodal pore structures with high surface areas and pore volumes, were fabricated. The separation of chiral AAs by adsorption onto the heterogeneous (S)-ARCA was performed using a continuous flow type packed bed reactor system. The effects of loading amount of ARCA on the support, the molar ratio of AA to ARCA, flow rates, and the type of phase transfer reagent (PTR) on the isolation yields and the optical purity of product D-AAs were investigated. D-AAs were selectively combined to (S)-ARCA through imine formation reaction in an aqueous basic solution of racemic D/L-AA. The (S)-ARCA coated MMC support showed a high selectivity, up to 95 ee%, for the separation of D-type phenylalanine, serine and tryptophan from racemic mixtures. The ionic liquids TPPC and OTPPBr exhibited superior properties to those of the ionic surfactant Cetyltrimethyl ammonium bromide (CTAB), as a PTR, showing constant optical purities of 95 ee%, with high isolation yields for five repeated reuses. The unique separation properties in this heterogeneous adsorption system should provide for an expansion of the applications of porous materials for commercial processes.

• Atmosphere
• /
• v.23 no.4
• /
• pp.453-470
• /
• 2013

As a part of the KIAPS Observation Processing System (KOPS), we have developed the modules of satellite radiance data pre-processing and quality control, which include observation operators to interpolate model state variables into radiances in observation space. AMSU-A (Advanced Microwave Sounding Unit-A) level-1d radiance data have been extracted using the BUFR (Binary Universal Form for the Representation of meteorological data) decoder and a first guess has been calculated with RTTOV (Radiative Transfer for TIROS Operational Vertical Sounder) version 10.2. For initial quality checks, the pixels contaminated by large amounts of cloud liquid water, heavy precipitation, and sea ice have been removed. Channels for assimilation, rejection, or monitoring have been respectively selected for different surface types since the errors from the skin temperature are caused by inaccurate surface emissivity. Correcting the bias caused by errors in the instruments and radiative transfer model is crucial in radiance data pre-processing. We have developed bias correction modules in two steps based on 30-day innovation statistics (observed radiance minus background; O-B). The scan bias correction has been calculated individually for each channel, satellite, and scan position. Then a multiple linear regression of the scan-bias-corrected innovations with several predictors has been employed to correct the airmass bias.

• Journal of Embryo Transfer
• /
• v.10 no.2
• /
• pp.115-120
• /
• 1995

This study was carried out to investigate On in vitro fertilization, survival rate and developmental rate of rapidly frozen bovine immature oocytes. Immature oocytes cultured for 1, 12, 24, 48 hours in 20% FCS + TCM-199 medium and thereafter rapidly freezing-thawed oocytes inseminated with capacitated sperm. The immature oocytes following dehydration by 1.5M DMSO + 2.0M glycerol + 0.25M sucrose + TCM 199 media + 20% FGS were directly plunged into liquid nitrogen and thawes in 3$0^{\circ}C$ water. Rapid freezing embryos co-cultured in 20% FCS + TCM-199 media containing hormones(21U/mL PMSG, 21U /mL hGG and 1 $\mu$g /mL 17$\beta$-estradiol) and cumulus cells(1 x 105-6 cells). Survival rate was defined as development rate on in vitro culture or FDA-test. The results are summarized as follows ; 1. The in vitro maturation and fertilization rate of immature bovine oocytes on in vitro maturation period(1, 12, 24, 48 hrs) before rapid freezing4hawed were 57.1%, 45.7%, 37.1%, 25.7% and 40.0%, 31.4%, 20.0%, 11.4%, respectively. 2. The survival rate of immature bovine oocytes on in vitro maturation period(1, 12, 24, 48 hrs) before rapid freezing-thawed were 33.3%, 26.7%, 20.0%, and 10.0%, respectively. The survival rate of rapid freezing4hawed immature oocytes was significantly lower than that of non-freezing oocytes. 3. The survival rate of rapid freezing4hawed excellent and good bovine embryos co-cultured in 20% FCS + TCM-199 media containing hormones(PMSG, hCG, 17$\beta$-estradiol) and cumulus cells 4 to 5 hrs and 20 to 24 hrs were 35.0%, 15.0% and 25.0%, 15.0% and 40.0%, 20.0% and 30.0%, 15.0%, respectively. The survival rate of embryos co-cultured in TCM-199 media containing hormones and cumulus cells was significantly higher than that of non co-culture.

• Korean Journal of Animal Reproduction
• /
• v.26 no.4
• /
• pp.311-320
• /
• 2002

The objective of this study was to assess the developmental potential in vitro produced embryos frozen-thawed with the various containers, and also examined expression and localization of heat shock protein 70 at these embryos. For the vitrification, 2-cell, 8-cell and blastocyst stage embryos produced by in vitro fertilization (IVF) and nuclear transfer (NT) were exposed the ethylene glycol 5.5 M freezing solution (EC 5.5) for 30 sec, loaded on each containers such EM grid, straw and cryo-loop, and then immediately plunged into liquid nitrogen. Thawed embryos were serially diluted in sucrose solution, each for 1 min. and cultured in CRI-aa medium. Survival rates of the vitrification production were assessed by re-expanded, hatched blastocysts. There were no differences in the survival rates of IVF using EM grid and cryo-loop. However, survival rates by straw were relatively lower than other containers. The use of cryo-loop resulted in only survival of nuclear transferred embryos (43.7%). Also, there embryos after IVF or NT were analysed by semi-quantitive reverse transcription-polymerase chain reaction (RT- PCR) methods for hsp 70 mRNA expression. Results revealed the expression of hsp 70 mRNh were higher thawed embryos than control embryos. Immunocytochemistry used to localize the hsp 70 protein in embryos. Two and 8-cell embryos derived under control condition was evenly distributed in the cytoplasm but appeared as aggregates in some frozen-thawed embryos. However, in the control, blastocysts displayed aggregate signal while Hsp70 in frozen-thawed blastocysts appeared to be more uniform In distribution. Therefore, this result suggests that the exploiting Hsp 70 in the early embryos may be role for protection of stress condition for increase viability of embryos within IVF, NT and there frozen-thawed embryos.

• Journal of Embryo Transfer
• /
• v.23 no.2
• /
• pp.115-118
• /
• 2008

Glycerol is the cryoprotectant most frequently used to freeze semen in several of species. The objective of the present study was to compare the effect of three different glycerol concentrations (4, 6 or 8%, v/v) on frozen-thawed dog sperm survival rate. Ejaculates from 9 dogs collected by digital manipulation were pooled and assessed by macroscopic and microscopic criteria. Semen was divided into 3 aliquots, which were centrifuged and the sperm pellets rediluted with first Tris-glucose-citric acid extender. After 1 h cooling at $4^{\circ}C$, second extender containing 4, 6 or 8% glycerol was added, respectively. The semen was loaded into 0.25 ml straws and frozen and stored in liquid nitrogen and thawed. Sperm vigor, live:dead spermatozoa ratio using HOS test, and sperm morphology using $Spermac^{(R)}$ stain were evaluated. After thawing, there were no significant differences among groups in vigor, viability and morphology. In conclusion, the three glycerol concentrations (4, 6 or 8%) can be used successfully in cryopreservation of canine semen. Therefore the use of 4% glycerol in the extender has less toxic effect and reduces of freezing injuries.