• Journal of the Korean Society of Safety
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• v.8 no.1
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• pp.13-20
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• 1993

It is well known that mechanisms of fracture and fatigue crack propagation depend upon various characteristics such as environmental condition. crack geometry. heat treatment and mechanical properties. It seems to be important for the detailed evaluation of structural integrity to investigate the effects of the above factors on the behavior of structural components which contain flaws. In this paper. it is studied that the fatigue crack propagation of partly heat treated medium carbon steel (SM45C) by high frequency heat treatment.

• International Journal of Highway Engineering
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• v.14 no.5
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• pp.11-19
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• 2012

PURPOSES: The new methodology is proposed for estimation of long-term performance and pavement life based on the national highway database in Daejeon area. Furthermore, this study tried to verify the applicability of performance estimation using NHPCI (National Highway Pavement Condition Index) on tendency of pavement deterioration as time goes by under Korean road environments. METHODS: Reliability theories are applied to estimate the mean life and to determine the appropriate distribution using 3 levels of traffic loads (high, medium, low) based on maintenance and rehabilitation history data for 15 years. RESULTS: As a result, Lognormal distribution is suitable for explanation of pavement lifetime in Daejeon area regardless of traffic loads. In addition, we found that the results of mean life and maintenance timing based on NHPCI for the pavement sections of 3 levels of traffic loads are available. CONCLUSIONS: Based on this study, it was found that mean life of high, medium and low levels of traffic loads are about 8.1 years, 12.2 years and 12.7 years, respectively. Higher level of traffic loads shorten the pavement mean life.

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.12a
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• pp.12-14
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• 2004

Objective to know about pollution of ventilated system in super market and hotel's air condition in Kunming. Methods to take out 28 ventilated system from super markets and hotels in Kunming in march 2004. To check dirt amount in pipelines and microorganism in dirt. Testing result is appraised under 'Public hygiene standard of ventilated system in air condition'. Results pollution problem exist in different degree in all the super markets and hotels that have been investigated. There is 32.14% which means 8 hotels and 1 super market, pollution is serious, The others (67.86%) is medium. Conclusion pollution problems exist in air condition system in all super markets and hotels of Kunming. Discussion aim at Kunming's special weather, and present condition of public ventilated system, discussing ways of management in hygiene of air condition system.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.3
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• pp.109-124
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• 2018

In order to find the optimum culture condition for marine free-living nematoda in the laboratory, various agar media were developed and experiments were carried on nematodes. Nematodes have collected from the bottom of the sandy sediments' surface layer (about 5cm sediment) of Taean Mallipo beach's intertidal zone. Especially, with regard to agar medium, Killian medium was transformed slightly, density of agar had made a difference and this agar medium(height 2.0 mm on diameter 60 mm Petri dish) was divided. It was mixed with 5 different species of microorganism as nematodes' live food and added each culture medium. Five individuals of Enoplolaimus sp. on each culture medium were grown in a culture medium which was set on $20^{\circ}C$ and light blocked. Moreover, as a result of the optimum culture condition, 1.0% density of agar showed the highest survival rates (the average time of survival is 246.8 hours). On the other hand, the 0.4% density of agar adding Killian medium, bacto peptone and beef extract showed the lowest survival rates, which indicates the average time of survival is 27.6 hours. About Bathylaimus sp., on Killian medium's 1.0% density of agar(no feeding amount) showed the highest survival rates, which connects that the hatching rate 94.7% after 99.5 hours and it laid 7 eggs averagely on the spawning amount and the hatching rate experiment.

• Journal of Ginseng Research
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• v.21 no.1
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• pp.28-34
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• 1997

The effects of light on the pigment production and chloroplast development were examined on ginseng hairy roots cultured in 1/2MS liquid medium. The chlorophyll and carotenoid production were increased from 1,000 to 3,500 lux condition, but decreased drastically in 7,000 lux condition. The anthocyanin production was significantly increased with increment light intensity(1,000∼7,000 lux). The thylakoid membrane of chloroplast was proplastid in dark condition and it began to develop into thylakoid membrane in 1,000 lux condition and then intact thylakoid membrane was developed in 3,500 lux condition. However, the development of thylakoid membrane in 7,000 lux condition was inhibited comparing to 3,500 lux condition. The total chlorophyll production in blue light condition were high comparing to other wavelength and same as 40% of total chlorophyll on white light(3,500 lux) condition. The chlorophyll and carotenoid production by sucrose concentration were high in 3% sucrose condition and anthocyanin production was high in 4% condition. The production of chlorophyll and carotenoid by light periods was high when explants were cultured in dark condition for 1 week and then transferred to light condition for 4 weeks. Our results suggest that pigment production and chloroplast development could be accelerated by light Intensity of specific wavelength in cultures of ginseng hairy root.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.572-577
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• 2002

We investigated the optimal condition for production of bacterial cellulose with Gluconacetobacter persimmonus KJ145. For bacterial cellulose production, optimal medium composition and culture conditions were conducted to determine. Apple juice (10$^{\circ}$Brix) medium was suitable than Hestrin & Schramm medium which is generally used for the bacterial cellulose production. When 1% pyruvate as carbon source was added to apple juice, bacterial cellulose production rose to high level. The effect of various nitrogen sources was investigated: CSL was found to be essential to high cellulose yields and the optimal CSL concentration was 10%. Optimal temperature and culture time for the bacterial cellulose production was 35$^{\circ}C$ and 16 days, respectively At the optimal condition Gluconacetobacter persimmonus KJ145 produced 8.96g/L of bacterial cellulose (dry weight), which was much higher than reported values.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.63-63
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• 2022

Pear (Pyrus spp.) is a typical fruit and grown in the temperate climate regions throughout the world. Development of appropriate methods for in vitro propagation and root induction are important to increase the production rate and plant quality rapidly. This study was conducted to find the most appropriate media conditions for in vitro propagation and rooting of three pear cultivars, 'Barttlett', 'BaeYun No.3' and 'Oharabeni'. In vitro propagation was induced on Murashige and Skoog medium (MS) with 2.0 mg/L N6-benzyladenine (BA) and 0.2 mg/L indole-3-butyric acid (IBA) medium. For root induction of these cultivars, the shoot explants of the propagated plants were cultured on two different media containing 1/2 MS medium containing 0.2 mg/L IBA with 15 g/L Sucrose (Rooting Medium 1, RM1) and 1/4 Linsmaier and Skoog medium (LS) medium containing 1 mg/L IBA and 1 mg/L NAA hormone with 7.5 g/L glucose (Rooting Medium, RM2) and after 2 weeks, the plants on the RM2 medium are transferred on RM1 medium (RM2 condition). After nearly seven weeks, percentage of rooting formation were 22.2% in RM1 and 30% in RM2 conditions for Barttlett and 70% in RM1 and 60% in RM2 conditions for Oharabeni cultivars. No differences in these cultivars were observed between RM1 and RM2 conditions. However, BaeYun No.3 cultivar was observed 0% in RM1 and 72.7% in RM2 conditions. This study will help to propagation and root induction of in vitro plants for various pear cultivars.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.3
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• pp.347-353
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• 1997

This study was to test whether in vitro/in vivo survival of vitrified mouse blastocysts was influenced by culture conditions and ET method. Mouse blastocysts were obtained from in vitro fertilization and cultured for 4 days in M16 medium, and they were vitrified in EFS40 which contained 40% ethlyene glycol, 18% Ficoll and 0.5 mol sucrose in PBS. In experiment I, in vitro and in vivo survival rate of these embryos were evaluated in different culture condition after thawing. When thawed embryos were cultured in M16 medium as a control, m-CR1 medium contained 20 amino acids (2% BME amino acis and 1% MEM non-essential amino acids solution) and 4 mg/ml BSA and cumulus monolayer cell co-cultured condition in mCR1 medium (10% FBS), their in vitro survival at 24 hr after thawing was not affected by culture condition (75.6, 83.1, 82.4%). However, in vivo survival rates of implantation in m-CR1 medium (80.4%) were significantly higher than those of M16 medium (51.2%), co-culture (57.1%) condition, although there was no difference in live fetuses rates on day 15 gestation (39.0, 49.0, 38.1%). In experiment II, the in vivo development potential of embryos by ET methods was examined. When blastocysts were transferred to the day 2, 3 pseudopregnant recipient without culture soon after thawing, no pregnant recipient was obtained on the day 2 pseudopregnancy, and 50% of pregnancy rates and 15.4% of live fetus rates were obtained on the day 3 pseudopregnant recipients. These results were significantly lower than those of transferred group (day 3 pseudopregnant recipients) after culture for 16 hr post thawing (73.5, 57.1%) (p<0.05). In experiment III, to elevate usability of delayed embryos in vitro/in vivo survival of vitrified embryos (day 4 early, day 5 early and expanding blastocyst) were examined. in vivo survival rates (live fetus, total implantation) were higher in day 4 early blastocysts (33.3, 66.7%) than in day 5 expanding blastocysts (29.0, 38.7%), although the highest in vitro survival rates were obtained in the day 5 expanding brastocysts (78.3%). Therefore, these results suggest that the in vitro/in vivo survival rates of vitrified embryos could be improve by the culture condition and ET method and that the in vivo development rates of delayed embryos were decreased with longer culture duration in vitro. It means that more effective cryopreservation was obtained in day 4 early blastocysts than in day 5 expanding blastocysts.

• ALGAE
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• v.19 no.3
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• pp.271-276
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• 2004

One hundred and fifty four micro algal strains, newly isolated from nationwide freshwaters in Korea, were screened for their anticancer, ant diabetic, and antibiotic activities. The micro algal strains were cultured with different nutritional conditions that were divided into 4 groups as follows; a normal Allen medium, nitrogen (N)-limited medium, phosphorus (P)-limited medium, and N and P-limited medium. Algal biomass was extracted with a mixture of acetone:H₂O (1:1, v:v) and the extracts were used for the screening of bioactive materials. Anticancer, ant diabetic, and antibiotic materials were screened by the methods of vaccinia Hl-related protein tyrosine phosphates (VHR DS-PTPase) inhibition, protein tyrosine phosphates 1B (PTP1B) inhibition, and paper disk. The inhibition activity of VHR DS-PTPase was observed in 18 strains, having a maximum 79% inhibition from Anabaena affinis and the inhibition activity of PTP1B was observed in 9 strains, having a maximum 97% from Sphaerocystis schroeteri. Microcystis aeruginosa incubated in an N and P-limited medium showed antibiotic activity in 8 species out of 13 pathogenic bacteria. As a whole, it seemed that the stressed condition such as N and/or P limitation increased the production of bioactive materials in micro algae.

• Korean Journal of Medicinal Crop Science
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• v.10 no.4
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• pp.243-248
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• 2002

The effects of basal media, carbon, nitrogen, phosphate and some major macro elements on growth and shikonin production in Lithospermum erythrorhizon hairy root culture were studied. Among examined media, growth of hairy root cultured in B5 liquid medium was rapid, whereas shikonin production was high in MS liquid medium. Under B5 basal medium, sucrose concentration for optimal growth and shikonin production was 9% and 4% respectively. The growth and shikonin production on pH changes in B5 medium resulted little effect in pH 5.8 to pH 8.8 ranges, whereas growth was decreased dramatically in both above 8.8 and under 5.8. Nitrogen source and concentration effected on the growth and shikonin production. The highest growth rate was in B5 medium (50 mM $KNO_3$ and 1 mM $NaH_2PO_4)$, whereas the highest shikonin production was in the condition supplemented with 5 mM $KNO_3$ and 10 mM $NaH_2PO_4$.