• Korean Journal of Materials Research
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• v.8 no.11
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• pp.1020-1025
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• 1998

Irradiation-induced changes in mechanical properties and magnetic parameters were measured and compared to explore possible correlations for Mn-Mo-Ni low alloy steel surveillance specimens which were irradiated to a neutron fluence of $2.3\times10^{19}n/cm^2$(E>1.0MeV) in a typical pressurized water reactor environment at about $288^{\circ}C$. For mechanical property parameters, microvickers hardness, tensile and Charpy impact test were performed and Barkhausen noise amplitude, coercivity, remanence, maximum induction were measured for magnetic parameters. respectively. Results of mechanical property measurements showed an increase in yield and tensile strength, microvickers hardness. 41J indexed $RT_{NDT}$ and a decrease in upper shelf energy irrespective of base and weld metals. However, in the case of tensile properties, the changes in weld metal were negligible compared to the base metal. In the case of magnetic measurements, it is found that magnetic remanence, BN amplitude. BN energy have dropped significantly but coercivity(H,) has increased rapidly after irradiation. In this study. the measurements conducted on surveillance specimens of Mn-Mo-Ni low alloy steel showed that there were strong correlations between mechanical properties and magnetic properties.

• Korean Journal of Soil Science and Fertilizer
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• v.5 no.2
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• pp.1-38
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• 1972

This study, designed to establish a classification system of paddy soils and suitability groups on productivity and management of paddy land based on soil characteristics, has been made for the paddy soils on the Gimje-Mangyeong plains. The morphological, physical and chemical properties of the 15 paddy soil series found on these plains are briefly as follows: Ten soil series (Baeggu, Bongnam, Buyong, Gimje, Gongdeog, Honam, Jeonbug, Jisan, Mangyeong and Suam) have a B horizon (cambic B), two soil series (Geugrag and Hwadong) have a Bt horizon (argillic B), and three soil series (Gwanghwal, Hwagye and Sindab) have no B or Bt horizons. Uniquely, both the Bongnam and Gongdeog series contain a muck layer in the lower part of subsoil. Four soil series (Baeggu, Gongdeog, Gwanghwal and Sindab) generally are bluish gray and dark gray, and eight soil series (Bongnam, Buyong, Gimje, Honam, Jeonbug, Jisan, Mangyeong and Suam) are either gray or grayish brown. Three soil series (Geugrag, Hwadong and Hwagye), however, are partially gleyed in the surface and subsurface, but have a yellowish brown to brown subsoil or substrata. Seven soil series (Bongnam, Buyong, Geugrag, Gimje, Gongdeog, Honam and Hwadong) are of fine clayey texture, three soil series (Baeggu, Jeonbug and Jisan) belong to fine loamy and fine silty, three soil series (Gwanghwal, Mangyeong and Suam) to coarse loamy and coarse silty, and two soil series (Hwagye and Sindab) to sandy and sandy skeletal texture classes. The carbon content of the surface soil ranges from 0.29 to 2.18 percent, mostly 1.0 to 2.0 percent. The total nitrogen content of the surface soil ranges from 0.03 to 0.25 percent, showing a tendency to decrease irregularly with depth. The C/N ratio in the surface soil ranges from 4.6 to 15.5, dominantly from 8 to 10. The C/N ratio in the subsoil and substrata, however, has a wide range from 3.0 to 20.25. The soil reaction ranges from 4.5 to 8.0. All soil series except the Gwanghwal and Mangyeong series belong to the acid reaction class. The cation exchange cpacity in the surface soil ranges from 5 to 13 milliequivalents per 100 grams of soil, and in all the subsoil and substrata except those of a sandy texture, from 10 to 20 milliequivalents per 100 grams of soil. The base saturation of the soil series except Baeggu and Gongdeog is more than 60 percent. The active iron content of the surface soil ranges from 0.45 to 1.81 ppm, easily-reduceable manganese from 15 to 148 ppm, and available silica from 36 to 366 ppm. The iron and manganese are generally accumulated in a similar position (10 to 70cm. depth), and silica occurs in the same horizon with that of iron and manganese, or in the deeper horizons in the soil profile. The properties of each soil series extending from the sea shore towards the continental plains change with distance and they are related with distance (x) as follows: y(surface soil, clay content) = $$-0.2491x^2+6.0388x-1.1251$$ y(subsoil or subsurface soil, clay content) = $$-0.31646x^2+7.84818x-2.50008$$ y(surface soil, organic carbon content) = $$-0.0089x^2+0.2192x+0.1366$$ y(subsoil or subsurface soil, pH) = $$-0.0178x^2-0.04534x+8.3531$$ Soil profile development, soil color, depositional and organic layers, soil texture and soil reaction etc. are thought to be the major items that should be considered in a paddy soil classification. It was found that most of the soils belonging to the moderately well, somewhat poorly and poorly drained fine and medium textured soils and moderately deep fine textured soils over coarse materials, produce higher paddy yields in excess of 3,750 kg/ha. and most of the soils belonging to the coarse textured soils, well drained fine textured soils, moderately deep medium textured soils over coarse materials and saline soils, produce yields less than 3,750kg/ha. Soil texture of the profile, available soil depth, salinity and gleying of the surface and subsurface soils etc. seem to be the major factors determining rice yields, and these factors are considered when establishing suitability groups for paddy land. The great group, group, subgroup, family and series are proposed for the classification categories of paddy soils. The soil series is the basic category of the classification. The argillic horizon (Bt horizon) and cambic horizon (B horizon) are proposed as two diagnostic horizons of great group level for the determination of the morphological properties of soils in the classification. The specific soil characteristics considered in the group and subgroup levels are soil color of the profile (bluish gray, gray or yellowish brown), salinity (salic), depositonal (fluvic) and muck layers (mucky), and gleying of surface and subsurface soils (gleyic). The family levels are classified on the basis of soil reaction, soil texture and gravel content of the profile. The definitions are given on each classification category, diagnostic horizons and specific soil characteristics respectively. The soils on these plains are classified in eight subgroups and examined under the existing classification system. Further, the suitability group, can be divided into two major categories, suitability class and subclass. The soils within a suitability class are similar in potential productivity and limitation on use and management. Class 1 through 4 are distinguished from each other by combination of soil characteristics. Subclasses are divided from classes that have the same kind of dominant limitations such as slope(e), wettness(w), sandy(s), gravels(g), salinity(t) and non-gleying of the surface and subsurface soils(n). The above suitability classes and subclasses are examined, and the definitions are given. Seven subclasses are found on these plains for paddy soils. The classification and suitability group of 15 paddy soil series on the Gimje-Mangyeong plains may now be tabulated as follows.

• Journal of Sericultural and Entomological Science
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• v.16 no.1
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• pp.85-92
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• 1974

Many of studies on the transovarial transmission of occult virus and their activation due to various stresses such as cold or heat treatment, chemical feeding, and nutritional deficiency, etc., in the silkworm, Bombyx mori L. have been made, but any attempts have been not made to control virus diseases by detection of the occult virus-carried moths in the production of silkworm egg of hybrids, because of difficulty to detect occult virus in any stage. Therefore, it may be worth while to disclose whether a sublethal infection of the moths from which active virus are detectable, has the same level of induction rate as that of occult virus activation, thus to apply its results for the reduction of the occurence of virus diseases in silkworm rearing. For these purposes, the following experiment was conducted as one of preliminary steps. In this study, investigations on the generation-to-generation transmission of occult virus and a sublethal infection, and the role of chromosomal gene of the host, Jam 103 and Jam 104 in the Previous generation, and Jam 103 x Jam 103 and Jam 104 f Jam 104 in the next generation were made for the induction of virus diseases due to the transmitted virus. The frequency of cytoplasmic polyhedrosis due to the induction in the F$_1$ generation was markedly higher in the cross-batches, male$\times$female and male$\times$female in which inoculated individuals were used as fem ale parents than in the cross-batches, male$\times$female and male$\times$female in which virus has been not inoculated or inoculated only to male in the previous generation. The tendency of increasing rate was observed in any treatments; such as the inoculations of cytoplasmic polyhedrosis virus (10$\^$5/, 10$\^$6/ 10$\^$7, and 10$\^$8//ml ill different concentration of inocula) , cold-treatment (5$^{\circ}C$, 12hrs or 24hrs), and formalin-feeding treatment (2％ or 3％). The shape of polyhedra (tetragonal in outline) examined in the F, larvae was identified as that of the inoculated polyhedra with partial application of immunofluorescent techniques. These results suggests that the cytoplasmic polyhedrosis virus in B. meri L. are transmitted to the next generation through the egg, apparently in the occult state. And the experimental results of various cross-batches revealed the egg cytoplasm plays an important part i the transmission of the occult virus of the cytoplasmic polyhedrosis virus,

• Tuberculosis and Respiratory Diseases
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• v.48 no.2
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• pp.166-179
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• 2000

Background: The main reason for the failure of anti-cancer chemotherapy is the build up of resistance by cancer cells to apoptosis. The activation of NF-${\kappa}B$ in many cancer cell lines is reported to be underlying mechanism behind the build up of resistance of cancer cells to apoptosis. However, this relationship varied depending on the cells used in the experiments. In this study, the role of NF-${\kappa}B$ activation in the TNF-$\alpha$-induced apoptosis in lung cancer cell line was evaluated. Methods: NCI-H157 cells were used in all experiments. Cells were exposed to a high dose of TNF-$\alpha$(20 ng/ml) for 24 or 48 hours with or without blocking NF-${\kappa}B$ activation. TNF-$\alpha$-induced activation of NF-${\kappa}B$ was inhibited either by overexpression of $I{\kappa}B{\alpha}$-super repressor($I{\kappa}B{\alpha}$-SR) or by pre-treatment with proteasome inhibitor. Cell viability and apoptosis were evaluated with MTT assay and Western blot analysis for PARP fragment, respectively. Results: Cell viability of NCI-H157 cells was not affected by TNF-$\alpha$ treatment alone; however, combined treatment with TNF-$\alpha$ and cycloheximide reduced cell viability significantly, indicating that resistance to TNF-$\alpha$ is mediated by the new proteins synthesized after TNF-$\alpha$ stimulation. To evaluate the role of NF-${\kappa}B$ in the transcription of anti-apoptotic proteins. delete NF-${\kappa}B$ activation was inhibited before TNF-$\alpha$ stimulation. as described above. $AD5I{\kappa}B{\alpha}$-SR-transduction inhibited TNF-$\alpha$-induced nuclear translocation of p65. TNF-$\alpha$-induced cell death and apoptosis increased after inhibition of TNF-$\alpha$-induced activation of NF-${\kappa}$ by methods. Conclusion: These results suggest that TNF-$\alpha$-induced activation of NF-${\kappa}B$ may be closely related to the acquisition of the resistance to TNF-$\alpha$-induced apoptosis in lung cancer cells. Therefore. blocking of NF-${\kappa}B$ pathway can be a useful therapeutic modality in the treatment of lung cancer.

• Journal of Animal Science and Technology
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• v.45 no.6
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• pp.923-932
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• 2003

This study was carried out to estimate the effects of breed and environment such as sex, test station, test year, test season, parity, initial and final weight on average daily gain, age at 90kg, backfat thickness, feed efficiency, lean percent and selection index on the basis of the performance data collected from 25,790 pigs of Duroc, Yorkshire and Landrace breeds which were performance-tested at the Korea Swine Testing Station from 1991 to 2002. The results obtained in the study are summarized as follows; 1. The means of the major economic traits were estimated as 959.95${\pm}$0.699g for average daily gain, 138.36${\pm}$0.072days for age at 90kg, 1.41${\pm}$0.001cm for backfat thickness, 2.33${\pm}$0.001 for feed efficiency, 56.71${\pm}$0.018% for lean percent and 221.65${\pm}$0.113 for selection index. 2. The effect of breed was statistically significant for all studied traits. Briefly, Duroc showed the best performance for the average daily gain and age at 90kg. Landrace had the best performances for the backfat thickness and lean meat percent. In feed efficiency and selection index, Yorkshire had a better score than other breeds. 3. The least-squares means of female and male for the traits studied were 923.05${\pm}$1.289g and 974.53${\pm}$0.856g for average daily gain, 139.74${\pm}$0.145days and 137.21${\pm}$0.097days for age at 90kg, 1.49${\pm}$0.002cm and 1.39${\pm}$0.002cm for backfat thickness, 2.43${\pm}$0.002 and 2.28${\pm}$0.002 for feed efficiency, 56.43${\pm}$0.034% and 56.81${\pm}$0.023% for lean percent and 211.37${\pm}$0.194 and 224.61${\pm}$0.129 for selection index. Therefore, males were superior to females for all traits examined. 4. The effect of test station was statistically significant for all traits except for selection index. Performances for age at 90kg, backfat thickness, feed efficiency and lean meat percent collected from Test station 2 were higher than those from Test station 1. However, Test station 1 showed better average daily gain. 5. The initial weight and final weight included as a covariate in this study had a significant influence on average daily gain, age at 90kg, backfat thickness, feed efficiency and selection index. From the absolute values of the estimated regression coefficients, it was inferred that the final weight had greater effect for the investigated traits than the initial weight.

• Journal of Animal Science and Technology
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• v.45 no.1
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• pp.113-122
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• 2003

Net and metabolizable energy requirements for maintenance of Hanwoo (Korean native cattle) bulls were estimated in twenty-eight fasting metabolism trials using seven different feeds at four stages of body weight(100, 200, 300 and 400kg). Three cattle for each of twenty-eight trials fed at a level of maintenance energy requirement were housed in metabolic stalls during the 5 days of collection period. Thereafter, during the 2 days of respiration period the heat production was measured by indirect calorimetry using respiratory chamber. After finishing the respiratory metabolism trials under the maintenance level, experimental animals were fasted for 5 days and were measured heat production by indirect calorimetry using respiratory chamber. Seven different feeds were: 1) mixed ration of concentrate and rice straw, 2) mixed ration of concentrate and mixed grass hay, 3) mixed ration of concentrate and corn silage, 4) rice straw alone, 5) mixed grass hay alone, 6) corn silage alone, 7) concentrate alone. Fasting heat production were 66.05/$W^{0.75}$ at 100kg of body weight and 60~63kcal/$W^{0.75}$ at 200~400kg of body weight. When subtracting heat loss by muscular work from the fasting heat production, basal metabolic rate was 55.92kcal/$W^{0.75}$. The average values of NEm requirements were obtained by adding urinary energy excretion to the basal metabolic rates were 69.1, 62.1, 65.8 and 64.4kcal/$W^{0.75}$ for the four stages of body weight, respectively. The ME requirement for maintenance could be calculated using retained energy and the efficiency of utilization of ME for net energy. The ME requirement for maintenance thus obtained was 102.69kcal/$W^{0.75}$.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.4
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• pp.255-264
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• 2003

A study was conducted to determine the effects of pig slurry application on forage yield and growth of fazing Hanwoo heifer in a mixed pasture. To each of three treatments 1.4ha were alloted a control applied with only chemical fertilizer (N-P-K=150-150-120kg/ha), two pig slurry lots applied with the amount to allow 100% (150 kg/ha) or 150% (225 kg/ha) of N used in the control. A randomized block design was used without replication. Cattle were allowed to graze continuously during the experimental period. Results obtained were as follows: Total dry matter yield was 16,291, 15,632 and 16,320 kg/ha for chemical fertilizer. pig slurry 100% and 150％, respectively. The pasture was dominated by perenial ryegrass during the first gazing season, but by orchard grass and perenial ryegrass (60∼70%) and red clover (20∼30%) during the second grazing season. Average gazing rate per ha was 2.75∼2.76 animal units and daily weight gain of grazing cattle was not different among treatments ranging from 0.563 to 0.580 kg. Total weight gain of grazing cattle per ha during the grazing period was 541, 541 abd 555 kg for chemical fertilizer, pig -slurry 100 and 150%, respectively. RBC, WBC, total protein and albumin etc. concentrations in blood were normal in all treatments.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.1-7
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• 2005

Tidal flats have been regarded to carry out transformation and removal of land-derived organic matter, and this purifying capability of organic matter by tidal flats is one of very important reasons for their conservation. However, integral biogeochemical studies on production and decomposition of organic matter by benthic microbes in tidal flats have been absent in Korea, although the information is indispensable to quantification of the purifying capability. Our major goals in this multidisciplinary research were to understand major biogeochemical processes and rates mediated by diverse groups of microbes dominating material cycles in the tidal flats, and to assess the contribution of benthic microbes to removal of organic matter and nutrients in the tidal flats. Our study sites were Ganghwa and Incheon north-port tidal flats that had been regarded as naturally well reserved and organically polluted, respectively. Our research group measured over 3 years primary production, biomass and community structure of primary producers, abundance and production of bacteria, enzyme activities, distribution of protozoa and protozoan grazing rates, rates of denitrification and sulfate reduction, early sediment diagenesis, primary production and respiration based on oxygen microelectrode. We analyzed major features of each biogeochemical process and their interactions. The results are compiled in the following articles in this special issue: An (2005), Hwang and Cho (2005), Mok et at. (2005), Na and Lee (2005), Yang et at. (2005), and Yoo and Choi (2005).