• Journal of Aquaculture
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• v.9 no.2
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• pp.179-186
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• 1996

Zoeal stage's larvae of pandalid shrimp Pandalus hypsinotus, is distributed off the East sea and esteemed as a valuable shrimp resource in Korea, were reared in $10^{\circ}C$ temperature-controlled chambers and inverstigated the energy budget. The total energy intake per larva of zoea I to VI stages fed on Artemia nauplii was 140.88 J. The energy loss by respiration, molting, and excretion were 16.22 J, 1.19 J, and 106,40 J, respectively. The amount of energy used by growth was 17.07 J. Pandalid larvae assimilated $24.47\%$ of the ingested food. The gross efficiency ($K_1$) calculated by the equation of (growth+exuviae)/ingestion $rate{\times}100$ was $12.96\%$, and the net growth rate ($K_2$) calculated by the equation of (growth rate + exuviae)/(growth rate+ exuviae+ respiration rate)${\times}100$ was $52.96\%$. The percentage used for somatic growth and maintenance among the assimilated energy were $49.51\%$ and $47.04\%$ respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.6
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• pp.641-645
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• 1995

This study was conducted to develop a method for production of nuclear transplant bovine embryos using in vitro-matured (IVM) oocytes and to examine the effect of different conditions of electrofusion on fusion rate and developmental capacity of donor nucleus transplanted to enucleated oocytes. Eight- to sixteen-cell embryos derived from oocytes matured and fertilized in vitro used as donor blastomeres and IVM oocytes were used as recipient oocytes. Oocytes were enucleated immediately after 23-24 h IVM and then reconstituted with a donor blastomere in two different micromanipulation media. Fusion rate and subsequent development of the reconstituted oocytes was compared under the different electric stimuli and recipient oocyte ages. Success rate of enucleation was significantly higher in TCM-199 medium containing FCS than in DPBS. The high fusion rate(75-94%) and development (6.4-14.8%) to morulae and blastocyst (M + B) were obtained from 0.6-0.75 kV/cm DC voltage, although total cleavage was not different among the electric pulses. Most optimal condition of electric stimulation for fusion and development was 1 DC voltage of 0.75 kV/cm, in which 80.5% of oocytes were fused, 80.0% and 31.7% of which was cleaved and developed to M + B, respectively. No M + B was obtained from 1.2 kV/cm DC voltage regardless of pulse frequency. Recipint oocyte age at electrofusion greatly affected the cleavage and subsequent development to M + B, showing high rate at 40-41 h oocyte maturation. These results suggest that a suitable condition of electrofusion for donor nuclei derived from IVF may be 1-2 DC pulses of 0.7 kV/cm for $70{\mu}sec$ and that processing of a transplanted nucleus in IVM oocytes may be affected by maturation age of recipient oocytes.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.4
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• pp.281-287
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• 2013

Due to its high salt content and poor physical properties in reclaimed tidal lands, it is important to ameliorate soil physical properties to improve the efficiency of desalination. The objective of this study was to evaluate the changes of soil properties at Saemangeum reclaimed tidal saline soil with various soil amendments. Field experiment was conducted at Saemangeum reclaimed tidal land in Korea and the dominant soil series was Munpo series (coarse loamy, mixed, nonacid, Mesic, Typic, Fluvaquents). Woodchips, crushed-stone, oyster shell, coal bottom ash, and rice hull were added as soil amendments and mixed into surface soil to improve soil physical properties. There was large variability in soil hardness, but oyster shell treatment was significantly lower soil hardness at surface layer. Soil hardness was not significantly different below 15 cm depth. Infiltration rate was also significantly greater at oyster shell treatment. This may be due to the leaching of Ca ions from oyster shell and improved soil properties. However, there was no statistical significant difference of the soil bulk density, moisture content, and porosity. Improved physical properties increased desalinization rate in soil and retarded the resalinization rate when evapotranspiration rate was high. Although soil salinity was significantly decreased with oyster shell amendment, soil pH was increased that should be made up as a soil amendment. Our results indicated that oyster shell application increased infiltration rate and improved soil hardness, and thus oyster shell could be used to improve soil salinity level at Saemangeum reclaimed tidal saline soil.

• Clinical and Experimental Reproductive Medicine
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• v.19 no.2
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• pp.133-141
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• 1992

We examined effects of co-culture with human oviduct epithelial cells (HOEC) on the development of mouse and human embryos from early embryonic· stage to late morula or blastocyst stage (LM or B). In human, embryos were transferred and pregnancy rate was investigated. The HOEC, collected from surgically removed fallopian tube, were cultured in medium-199 supplemented with 20 % fetal cord serum (FCS). The HOEC were characterized by using immunocytochemical staining with anticytokeratin antibody and then used for cultures of mouse and human embryos. Results obtained from co-culture system were as follows. Development rate of mouse embryos was improved by co-culture system at late developmental stage (p<0.025). Human supernumerary embryos remained after transfer, unsuitable for freezing because of their poor quality, were co-cultured for 72hrs. Co-culture (78.79%) or conditioned medium (78.26%) system improved the developmemt rate, significantly, in comparision with control (11.11%)(p<0.00l). Co-cultured (85.71%) human zygotes for 24hrs showed the better development rate in comparision with control (50.00%) (p<0.01). When we transferred embryos cultured with the HOEC to patients, we obtained one pregnancy. Co-cultured human zygotes for 24hrs showed the better quality and viability for the replacement in comparision with control (p<0.01). In addition, improved pregnancy rate was obtained. Our results suggest that the co-culture system can rescue early degenerating embryos by improving early development and yield a resonable number of blastocyst for the appropriate replacement. The effect provided by cultured HOEC is not species specific for the development of embryos and it can be used to overcome in vitro blocks for the development. And also the co-culture system offers the possibility to freeze embryos at blastocyst stage which is more sucessful stage for the freezing. The HOEC monolayer may provide some stimulus via specific factor, which is unknown, to the development of embryos. Our results showed that the co-culture system with HOEC can be an alternative to conventional culture system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.3
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• pp.234-240
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• 2014

We investigated the effects of feeding rate on the growth performance, blood components, and histology of growing olive flounder Paralichthys olivaceus. We determined the optimum feeding rate (initial fish mean weight of $240{\pm}10.9$ g) at the optimum water temperature. Two replicated groups of fish were fed a commercial diet at rates of 0%, 0.5%, 0.75%, and 1.0% body weight (BW) per day, and to satiation. Feeding trial was conducted using a flow-through system with 10 1.2-metric ton aquaria receiving filtered seawater at $19-21^{\circ}C$ for three weeks. Weight gain (WG) for fish fed to satiation was significantly higher than that of unfed fish and fish fed at 0.5% and 0.75% BW per day. The WG of fish fed at 1.0% BW per day was significantly higher than that of unfed fish and of fish fed at 0.5% BW per day. However, there were no significant differences in WG between fish fed at 0.5% BW per day and those fed at 0.75% BW per day, between fish fed at 0.75% BW per day and those fed at 1.0% BW per day, and between fish fed at 1.0% BW per day and those fed to satiation. The specific growth rates of fish fed at 1.0% BW per day and those fed to satiation were significantly higher than those of unfed fish and of fish fed at 0.5% BW per day. Broken-line regression analysis of weight gain showed that the optimum feeding rate of olive flounder weighing 240 g was 1.09% BW per day at the optimum water temperature.

• Corrosion Science and Technology
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• v.4 no.3
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• pp.75-80
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• 2005

This work dealt with the evaluation of galvanic corrosion rate in a corrosion cell having annular gap of 0.5 mm between carbon steel 1018 and alloy 600 as a function of temperature and boron concentration. Temperature and boron concentration were ranged from 110 to 300 $^{\circ}C$ and 2000~10000 ppm, respectively. After the operating temperature of the corrosion cell where the electrolyte was injected was attained at setting temperature, galvanic coupling was made and at the same time galvanic current was measured. The galvanic corrosion rate decreased with time, which was described by corrosion product such as protective film as well as boric acid deposit formed on the carbon steel with time. From the galvanic current obtained as a function of temperature and boron concentration, it was found that the galvanic corrosion rate decreased with temperaturewhilethe corrosionrate increasedwith boronconcentration. The experimental resultsobtained from galvanic corrosion measurement were explained by adhesive property of corrosion product such as protective film, boric acid deposit formed on the carbon steel wall and dehydration of boric acid to be slightlysolubleboric acid phase.Moreoverthe galvaniccorrosionrate calculatedusing initialgalvaniccoupling current instead of steady state coupling current was remarked, which could give us relatively closer galvanic corrosion rate to real pressurized water reactor.

• Korean Journal of Community Nutrition
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• v.7 no.3
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• pp.345-353
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• 2002

A survey was carried out to investigate the breastfeeding knowledge, breastfeeding rates ultra related factors among women in Seoul and the Chungbuk area, in order to obtain baseline data for the development of an education program on breastfeeding. Subjects included 671 lactating mothers who visited public health or pediatric centers, between December, 1999 and February, 2000 and were interviewed using a questionnaire. The results are as follows: In the breastfeeding knowledge, most of the subjects (93.4%) know correctly that 'breastfeeding is better for a baby's emotional development than formula feeding,'whereas only half of the subjects (51.7%) answered correctly the question on whether 'formula is more nutritious than breastmilk.'The breastfeeding rates were about 57%, 40%, 33% and 12%, respectively for baby's aged 1, 3, 6, and 12 months. These results showed that the breastfeeding rate rapidly decreased with the baby's age. Lower breastfeeding rates were associated with high educational level (college graduate and above), high income, mothers'employment, no experience of attending breastfeeding education programs, and no planning on breastfeeding prior to pregnancy. There was a significant relationship between the level of knowledge and breastfeeding practice; the higher the knowledge score, the higher the breastfeeding rate. In conclusion, an education program should be developed and offered for each low breastfeeding rate group, in order to promote breastfeeding.

• The Korean Journal of Malacology
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• v.21 no.1
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• pp.65-70
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• 2005

The purpose of this study is to determine the appropriate substrate for larval settlement and spat growth in the purple clam, Saxidomus purpuratus in laboratory culture. Larvae were reared with 3 different types of sediments (mud, sand, and mixed) for 46 days in settlement experiment, and settled spats were further grown in 3 types of sediments for 36 weeks in growth experiment. The density of settled spats in muddy sediments was more than 2 times higher than those in mixed or sandy sediments. But, the average size of settled spats in muddy sediments was smaller than those in mixed or sandy sediments. After 36 weeks of growth period, growth rate decreased as shell length increased. When shell length was less than 2 mm, growth rate in mixed sediments was significantly higher than that in sandy sediments. When shell length was more than 2 mm, there was no significant difference in growth rate among different substrates. Sediment type affected growth rate only when the spats were relatively small (less than 2 mm). Muddy sediments seems better for larval settlement, while mixed sediments is best for spat growth. We suggest the laboratory procedure for enhancing seedling production of S. purpuratus.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.3
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• pp.261-271
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• 2006

The present study is aimed at evaluating the economic effectiveness of Abalone, haliotis discus hanai Releasing Project(ARP) conducted in the fishing ground owned by a fishing village in Ulsan, Korea. The results were summarized as follows: First, an average ratio of released abalones in the total landing after releasing is shown to be 85.0%. Second, the recapture rate of released abalones is 46.8%, exceeding the recapture rate of BEP(Break-Even-Point), 22.9%. Third, it is evaluated that total economic effectiveness of the ARP is 6.7-6.8 times, net effectiveness is 2.2-2.3 times, and the NPV(Net Present Value) discounted by a 8% interest rate is 474, 635 thousand wons, indicating the project is profitable. Considerable parts of the positive results on the ARP are based on some beneficial conditions, including the selection of favorable releasing sites, best self-regulation system of a fishing village for preservation of seaweed facilities and continued activities for protecting small abalones and their rearing. These results imply that the success of the ARP would be primarily dependent upon the selection of releasing site and effective management system after releasing.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.6
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• pp.844-852
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• 2017

Since guided weapon is high-cost and one-shot device which is non-reusable, it requires a lot of resources to prove required accuracy as a part of reliability demonstration. Once a test for proving accuracy rate of guided missile fails, it causes an additional cost and delay of schedule. This study introduces an equation for proper sample size and plan for guided-missile accuracy rate test in order to minimize the risk of test failure. Proper sample size for the test is derived by considering the reliability growth. Furthermore, each task for accuracy rate test is defined according to the development step. Therefore, this study can contribute to reduce sample size for accuracy rate test in order to meet the reliability requirement and assure transparency in the test process.