• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.1
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• pp.73-82
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• 1990

The experiment was carried out to study the influence of planting space and fertilizer application levels on some agronomic characters and yield in newly released semi-dwarf soybeans, Paldalbong and Dankyungkong. The number of branches per plant was not reduced by planting space from 60${\times}$10cm 30${\times}$15cm. These Semi-dwarf soybeans had good adaptability on high planting density. The number of pods per node on the main stem was different according to the planting space in Dankyungkong, but it was similar in Paldalkong except planting space 20${\times}$10cm. Regardless of planting densities and varieties, the number of grains per pod on upper node of the main stem was large. Coefficient of variation of pods and grains per node in the middle part of the main stem was small. The number of grains per plant was decreased in high planting density compared to low planting density, but the number of harvested plant per unit area was increased. Optimum planting space was 25${\times}$10cm in both varieties. The ability of nodulation was bigger in Dankyungkong than in Paldalkong.

• Korean Journal of Plant Tissue Culture
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• v.22 no.6
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• pp.317-322
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• 1995

As a basic research for breeding new varieties, reciprocal -intergeneric crosses between Citrus junos and P.trifoliata were made. F$_1$ hybrid production using in vitro ovule culture, gametogenesis, and fertilization phenomena were investigated. Frequency of fruit set resulting from crossing of Citrus junos and Poncirus Trifoliata was 16.6% while that of Poncirus Trifoliata and Citrus junos was 11.7%. Callus formation occurred well when ovules at the 6th week after pollination were cultured on MT (Murashige and Tucker) medium supplemented with zeatin 0.5 mg/L and NAA 1.0 or 3.0 mg/L. Immature ovules developed into mature embryos of the MT medium supplemented with 2,4-D 0.1 or 3.0 mg/L. Immature ovules developed into mature embryos of the MT medium supplemented with 2,4 D 0.1 or 0.5 mg/L. The invitro germination rates of 20-week-old ovules set C. junos $\times$ P. Trifoliata and P. Trifoliata $\times$ C. junos were 54.5% and 48.6%, respectively. The emergence ratios of trifoliate hybrids obtained by C. junos $\times$ P. Trifoliata and P. Trifoliata $\times$ C. junos were 56.7% and 100%, respectively. The chromosome number of C. junos and P. Trifoliata was n = 9 or 2n = 18, and the sizes of their pollen grain were 33.75 $\mu$ and 25.0 $\mu$. The length and width of embryo sac in C. junos and P. Trifoliata were 69.38~79.23 $\mu$ and 27.50~38.56 $\mu$, and those of egg cells were 17.50~41.50 $\mu$ and 6.25~8.12$\mu$. Fertilization of C. junos and P. trifoliata terminated 72 h after pollination.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.23-23
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• 2010

마찰교반접합(Friction Stir Welding)은 1991년 영국 TWI에서 개발된 접합 법으로서 일정한 속도로 회전하는 툴이 재료내부에 삽입 되면서 툴과 재료사이에서 마찰열이 발생하여 연화된 재료와 접합 툴 사이에서의 기계적 교반에 의해 소성변형이 일어남과 동시에 접합이 이루어진다. 마찰교반접합은 동적 재결정에 의한 접합부의 미세한 결정립 형성으로 인하여 기계적 특성이 향상되며 보호 가스가 필요 없어 친환경적임과 동시에 용융 용접 법에 비해 접합 시 에너지 소모가 적다는 장점이 있다. 마찰교반접합은 기존의 저융점 재료에 관한 접합을 넘어서 최근에는 철계 합금, 타이타늄 합금, 니켈계 합금 등 고융점 재료에서의 적용에 관한 연구가 이루어지고 있다. 하지만 마찰교반접합을 이용하여 위와 같은 강한 재료를 접합하기 위해서는 내구성이 갖추어진 툴이 반드시 수반된다. 슈퍼 오스테나이트계 스테인리스강은 염화물의 농도가 높은 부식 환경에 적용되는 소재로서, 공식(pitting corrosion) 및 틈부식 (crevice corrosion)에 대한 내식성을 높이기 위하여 Mo의 함량을 6%로 낮추고 20~25% Cr과 Ni을 첨가하여 사용된다. 이러한 고합금의 슈퍼 오스테나이트계 스테인리스강은 여타 내식성 합금에 비하여 내식성이 매우 우수한 것으로 알려져 있다. 최근 SO2 배출에 대하여 규제가 강화되면서 화력 발전소용 탈황 설비 중 일부 장비에서 6% Mo가 첨가된 슈퍼 오스테나이트계 스테인리스강의 사용이 늘어나고 있다. 본 연구에서는 $Si_3N_4$ 툴을 사용하여 Mo이 6% 첨가된 슈퍼 오스테나이트계 스테인리스강인 1925hMo강을 마찰교반접합하였다. 툴 회전속도 (200rpm, 300rpm, 460rpm, 700rpm)를 변수로 하여 접합을 실시하였다. 접합 후 외관상태를 점검하였으며 광학현미경 (optical microscope)과 주사전자현미경 (scanning electron microscope)을 사용하여 미세조직 관찰을 하였으며 경도 및 인장강도 측정 등의 실험을 통하여 접합부의 기계적 특성을 평가하였다. 그 후 이러한 결과를 통하여 미세조직과 기계적 특성과의 관련성을 조사하였다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.123-129
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• 1982

To determine the optimum harvesting date with good grain yield and quality, six different harvesting dates were tested from 25 to 50 days heading with five days intervals, using two varieties of Baekdong, naked barley and Olmil, wheat. The dates when grain yield, 1,000 grain weight and grain/whole spike weight ratio were reached to the highest were 35 and 40 days after heading for Baekdong and Olmil, respectively. Various grain qualities such as unhulled grain, plumpness, protein content and whiteness of grain were also very good at that times. One day earlier harvesting before the optimum dates resulted in yield decreases by 3.9% for Baekdong and 4.4% for Olmil. And it might be delayed for each 5 days with Combine harvesting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.166-170
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• 2012

This research was carried out to choose the suitable seedling type to transplanting in order to stabilize rice yield. The brief of this research to transplant the seedling divided into 10-day seedling, 20-day seedling, 30-day seedling, 33-day pot seedling in the field of Saemangeum Gyehwa, newly reclaimed land were following; Average salt content in 2 years was reduced from 0.16% to 0.04% after transplanting. Heading date of seedling type was Aug. 14 at 33-day pot seedling compared to 2 days at 30-day seedling, 3 days at 20-day seedling, 5 days late at 10-day seedling. Lodging index was highest at 30-day seedling, and also, field lodging was 50%. Ripening ratio and 1,000 grain weight were similar and panicle number was higher 20-day seedling > 10-day seedling > 33-day pot seedling > 30-day seedling. Rice yield was higher 10-day seedling = 20-day seedling > 33-day pot seedling > 30-day seedling. Head rice ratio was higher in 20-day seedling > 30-day seedling = 10-day seedling > 33-day pot seedling. Amylose content and protein content was not significantly different between seedling types. With this results, the suitable seedling types in newly reclaimed land are 10-day and 20-day seedling.

• Analytical Science and Technology
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• v.6 no.2
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• pp.167-180
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• 1993

The effects of coating variables on the formation of aluminide coating layer with good oxidation resistance on the strongest hot-forged superalloy in the world, KM 1557 developed at KIST by pack cementation process were studied. Pack aluminizing were performed by high-activity process with pure aluminium powders and by low-activity process with codep powders. For high-activity process, Al deposition rate, growth rate of coating layer, and cross-sectional microstructures were influenced by the species and additive amounts of activators and the additive amounts of pure aluminium powders. For low-activity process, Al deposition rate, growth rate of coating layer, and the cross-sectional microstructures were not influenced by the species but additive amounts of activators. Surface structures of coating layer were influenced by the species of activators. Regardless of aluminium activity, Al deposition rate was proportional to the square root of time and parabolic rate constants were different with the species of activators. The activation energy for deposition of aluminium was different with the species of activators for high-activity process. Regardless of the species of activators, the activation energy for deposition of aluminium was 12~14 Kcal/mole for low-activity process.

• Journal of fish pathology
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• v.11 no.1
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• pp.35-41
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• 1998

We investigated the optimal concentration of lidocaine and MS-222 (tricaine methanesulfonate) for the exfoliation and recovery of abalone, Haliotis discus hannai in different shell lengths, for the purpose of preventing the damage of shell and muscle. However, most anaesthetics applied at present have a strong toxic effect on abalone. MS-222 is the only anaesthetic which is approved for use in food fish by FDA, and lidocaine belongs to a group of anaesthetic which are used in human medicine. These chemicals were evaluated as anaesthetic for different shell size of abalone. The response varied for different shell size groups (shell length 1, 2 and 3 cm). In this study, we suggested the result that the exfoliation and recovery time by lidocaine and MS-222 in shell length 1 cm group were more shorter than in 3 cm group. In shell length 1 cm group, the optimal concentrations of lidocaine and MS-222 for anaesthetic were 200 ppm and 100 ppm, respectively. Lidocaine and MS-222 are preferable to other conventional abalone anaesthetics since these are cheap, safe and convenient to use.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.401-406
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• 2011

This study was conducted to investigate the pasting and sensory properties of different commercial rice cultivars. All samples had adequate moisture content, and Gyeonggi Kosihikari had the lowest protein content (6.75%). Apparent quality of head rice ranged from 85.63 to 98.70% and amylose content was 21.51-26.54%. In a rapid visco analyzer examination, pasting temperature of Gyeonggi Kosihikari was the lowest (84.87). Breakdown of Gangwon Oade (43.64 RVU) was lower that of others, indicating the highest pasting stability. The setback of Jeonam Hitomebore was the lowest (81.56 RVU), suggesting slow deterioration. A texture analysis test showed that Gyeonggi Koshihikari had the lowest hardness and Chungnam Samgwang had the highest adhesiveness. Gyeonggi Koshihikari had the highest sensory scores for appearance, flavor, taste, texture and overall acceptability. These results indicate that Gyeonggi Koshihikari is the most adequate rice product among cultivars.

• Journal of the Korean Ceramic Society
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• v.40 no.10
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• pp.943-948
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• 2003

The microstructure and electrical characteristics of Zn-Pr-Co-Cr-Dy oxides-based varistors were investigated with Dy$_2$ $O_3$ content in the range of 0.0∼2.0 ㏖%. As Dy$_2$ $O_3$ content is increased, the average grain size was decreased in the range of 18.2∼4.6 $\mu\textrm{m}$ and the ceramic density was decreased in the range of 5.49∼4.64 g/㎤. The incorporation of Dy$_2$ $O_3$ markedly enhanced the nonlinear properties of varistors more than 9 times in nonlinear exponent, compared with the varistor without Dy$_2$ $O_3$ The varistor with 0.5∼1.0 ㏖% Dy$_2$ $O_3$ exhibited the high nonlinearity, in which the nonlinear exponent is above 55 and the leakage current is below 1.0 ${\mu}\textrm{A}$. The donor concentration and the density of interface states were decreased in the range of (4.66∼0.25)${\times}$10$\^$18//㎤ and (5.70∼1.39)${\times}$10$\^$12//$\textrm{cm}^2$, respectively, with increasing Dy$_2$ $O_3$ content. The minimum dielectric dissipation factor of 0.0023 was obtained for 0.5 ㏖% Dy$_2$ $O_3$, but further addition of Dy$_2$ $O_3$ increased it.

• Korean Journal of Materials Research
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• v.10 no.12
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• pp.807-811
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• 2000

CeO$_2$ and SrBi$_2$Ta$_2$O$_{9}$ (SBT) thin films for MFISFET (Metal-ferroelectric-insulator-semiconductor-field effect transistor) were deposited by r.f. sputtering and pulsed laser ablation method, respectively. The effects of sputtering gas ratio(Ar:O$_2$) during deposition for CeO$_2$ films were investigated. The CeO$_2$ thin films deposited on Si(100) substrate at $600^{\circ}C$ exhibited (200) preferred orientation. The preferred orientation, Brain size and surface roughness of films decreased with increasing oxygen to argon gas ratio. The films deposited under the condition of Ar:O$_2$= 1 : 1 showed the best C- V characteristics. The leakage current of films showed the order of 10$^{-7}$ ~10$^{-8}$ A at 100kV/cm. The SBT thin films on CeO$_2$/Si substrate showed dense microstructure of polycrystalline phase. From the C-V characteristics of MFIS structure with SBT film annealed at 80$0^{\circ}C$, the memory window width was 0.9V at 5V The leakage current density of Pt/SBT/CeO$_2$/Si structure annealed at 80$0^{\circ}C$ was 4$\times$10$^{-7}$ /$\textrm{cm}^2$ at 5V.