• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.174-178
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• 1986

This experiment was carried out to study the influence of temperature treatments on germination of sorghum (cv. Pioneer 931), sorghum-sudangrass (cv. Pioneer 988), sudangrass (cv. Piper) and corn (cv. Suweon 19) in growth chamber. Each crop seeds were germinated under different day/night temperature of 10/5, 15/10, 20/15, 25/20, 30/25, 35/30 and $40/35^{\circ}C$ over 14/10 hour days. The results obtained are summarized as follows. 1. Germination of sorghum and sorghum-sudangrass were less affected by high temperature than those of corn and sudangrass. The optimum temperatures for germination were $20-40^{\circ}C$ for sorghum and $20-30^{\circ}C$ for corn. High temperature($40/35^{\circ}C$), however, resulted in great decrease of seed germination rates of seed germination rates of corn, while those of sorghum and sorghum-sudangrass shown high germination rates with the value of 95.8% and 89.9%, respectively. 2. Sorghum-sudangrass hybrid was shown to have a great tolerance to low temperature. Under low temperature($10/5^{\circ}C$) seed germination of sorghum-sudangrass was 80.0% but those of corn and sudangrass were 43.2% and 24.8% respectively. Germination rates of sorghum were decreased to about 68.8% at low temperature from a value of 98.1% at optimum temperature. 3. The days required to the seed germination of sorghum and sorghum-sudangrass hybrid were shortened by increasing of temperature. Under different temperature treatments, it was required 12 days ($15/10^{\circ}C$), 6 days ($25/20^{\circ}C$) and 3 days ($40/35^{\circ}C$) in sorghum but corn required 16, 7 and 3 days, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.1
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• pp.7-12
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• 2009

This experiment was conducted to compare the agronomic characteristics and productivity in introduced forage pea cultivars at the experimental field. The experiment was arranged in a randomized block design with three replications. The forage pea used in this study were two cultivars ('Livioletta', 'Austrian Pea') and one Chinese milk vetch cultivar (Chinese domestic cultivar). Flowing of 'Livioletta' cultivar was May 16th and 'Austrian Pea' cultivar was 18th May, 20 days later than the former. The 'Livioletta' cultlvar showed stronger than winter hardiness of 'Austrian Pea' cultivar. Dry matter (DM) content of 'Liviotetta' and 'Austrian Pea' cultivars were 22.5% and 20.9% chinese milk vetch showed the lowest content with 17.7%. 'Austrian pea' cultivar showed the highest DM yield with 5,617 kg/ha but the DM yield of 'Livioletta' cultivar was low with 3,652 kg/ha. The yield of CP (crude protein) and TDN (total digestible nutrient) set high at 'Austrian Pea' cultivar. And 'Livioletta' and 'Austrian Pea' cultivars showed CP content with 15.5% and 14.4% but Chinese milk vetch with 19.3%. The acid detergent fiber (ADF) and neutral detergent fiber (NDF) content of 'Austrian Pea' cultivar were 23.2% and 40.3%. Therefore 'Austrian pea' cultivar seems to be suitable varieties in paddy field as winter forage crops.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.27-32
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• 2010

This study was conducted to monitor aflatoxins in various medicinal herbs, providing available data for the safety of those products. To monitor aflatoxins in medicinal herbs, a total of 400 samples of 40 different herbs were collected in commercial retailers in Seoul, Daejeon, Gwangju, Daegu, and Busan from March to August, 2008. The samples that passed the sensory evaluation were tested for aflatoxins. Aflatoxins in samples were analyzed by HPLC-florescence coupled with photochemical enhancement. Samples were extracted with 70% methanol and then diluted to the appropriate concentration. A refining process was performed using an immunoaffinity column. The analytical method used in this study was validated. The $R^2$ value for aflatoxin $B_1$ was 0.99946, and the detection range was from 0.25 to 10.0 ng/mL. The accuracy of the analysis was ranged from 83.2% to 101.8%. The relative standard deviation (RSD) in the aflatoxin $B_1$ analysis was 3.4%, demonstrating the precision of this method. In addition, the detection limit and quantitative analysis limit of aflatoxin $B_1$ was $0.53\;{\mu}g/kg$ and $1.76\;{\mu}g/kg$, respectively. These results indicated that the analytical method used in this study was appropriate. The results of HPLC showed that 1% (4 samples) of the samples may contain aflatoxins. The concentration of quantified aflatoxin was $2.3\;{\mu}g/kg$ for both Quisqualis fructus and Remotiflori radix samples. The other samples were below the limit of quantification. Moreover, the concentration of aflatoxin $B_1$ which is made by specific fungi were below the level of regulation. Only 20% of aflatoxin $B_1$ were transferred to hot water. Therefore, the levels of aflatoxins in medicinal herbs were considered to be safe especially considering the aflatoxin transfer ratio.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.135-135
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• 2018

천이금속 질화물 코팅은 우수한 기계적 특성들로 인해 공구 코팅으로 많이 사용 되어왔다. 그 중에서도 특히 Cr계 경질 코팅은 높은 경도와 낮은 표면조도, 우수한 마찰특성 등 뛰어난 기계적 특성을 나타내므로 공구 코팅으로의 적용 가능성이 크다. 그러나 최근 공구산업의 발전으로 인해 공구가 더욱 가혹한 환경에서 사용됨에 따라, 공구의 수명을 향상시키고 보호하기 위해 코팅의 높은 밀착력이 요구되고 있으며, 모재와 코팅 사이에 중간층을 합성함으로써 공구의 밀착력을 향상시키는 연구가 활발히 진행되고 있다. 이전 연구에서 모재/중간층/코팅간의 경도와 탄성계수 비율(H/E ratio)의 구배가 코팅의 밀착력에 큰 영향을 미치는 것으로 확인되었다. 그러므로, WC 모재와 Cr계 코팅의 중간값의 H/E ratio를 갖는 중간층의 합성을 통해 코팅의 밀착력을 향상시킬 수 있을 것으로 판단된다. 본 연구에서는, 코팅의 밀착력을 향상시키기 위해 다양한 중간층을 증착한 CrZrN, CrAlN 코팅을 비대칭 마그네트론 스퍼터링 장비를 이용하여 합성하였다. 모재로는 디스크 형상의 WC-6wt.%Co 시편을 사용하였고 Cr, Zr, Si, Al single 타겟을 이용하여 Cr, CrN, CrZrN, CrZrSiN 등의 중간층이 증착된 코팅을 합성했다. 코팅의 합금상, 경도 및 탄성계수, 미세조직 및 조성, 표면 조도을 확인하기 위해 X-ray diffractometer (XRD), Fischer scope, field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy를 사용하였고, 코팅의 밀착 특성을 분석하기 위해 scratch tester와 optical microscopy (OM)를 이용하였다. 코팅의 내열성을 확인하기 위해 코팅을 furnace에 넣어 공기중에서 500, 600, 700, 800, 900, $1,000^{\circ}C$로 30분 동안 annealing 한 후에 nano-indentation을 사용하여 경도를 측정하였다. CrZrN 및 CrAlN 코팅을 나노 인덴테이션으로 분석한 결과, 모든 코팅의 경도(33.4-35.8 GPa)와 탄성계수(384.1-391.4 GPa)는 중간층의 종류에 상관없이 비슷한 값을 보인 것으로 확인됐다. 그러나, 코팅의 마찰계수는 중간층의 종류에 따라 다른 값을 보였다. CrZrN 코팅의 경우 CrN 합금상 중간층을 갖을 때 가장 낮은 값을 보였으며, CrAlN 코팅의 경우 CrN/CrZrSiN 중간층을 증착하였을때 마찰계수는 0.34로 CrZrN 중간층을 증착하였을 때(0.41)에 비해 낮은 값을 보였다. 또한, 코팅의 마모율 및 마모폭도 비슷한 경향을 보인 것으로 보아, CrN/CrZrSiN 중간층을 합성한 CrAlN 코팅의 내마모성이 상대적으로 우수한 것으로 판단된다. 코팅의 밀착력의 경우도 마찰계수와 비슷한 경향을 보였다. 이것은 중간층의 H/E ratio가 코팅의 내마모성에 미치는 영향에 의한 결과로 사료된다. H/E ratio는 파단시의 최대 탄성 변형율로써, 모재/중간층/코팅의 H/E ratio 구배에 따라 코팅 내의 응력의 완화 정도가 변하게 된다. WC 모재 (H/E=0.040)와 CrAlN 코팅(H/E=0.089) 사이에서 CrN, CrZrSiN 중간층의 H/E ratio는 각각 0.076, 0.083으로 모재/중간층/코팅의 H/E ratio 구배가 점차 증가함을 확인 할 수 있었고, 일정 응력이 지속적으로 가해지면서 진행되는 마모시험중에 CrN과 CrZrSiN 중간층이 WC와 CrAlN 코팅 사이에서 코팅 내부의 응력구배를 완화시키는 역할을 함으로써 CrAlN 코팅의 내마모성이 향상된 것으로 판단된다. 모든 코팅을 열처리 후 경도 분석 결과, CrN/CrZrSiN 중간층을 증착한 CrAlN 코팅은 $1,000^{\circ}C$까지 약 28GPa의 높은 경도를 유지한 것으로 확인 되었고, 이는 CrZrSiN 중간층 내에 존재하는 SiNx 비정질상의 우수한 내산화성에 의한 결과로 판단된다.

• Proceedings of the KSAR Conference
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• 2005.06a
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• pp.47-54
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• 2005

In boars, unlike the cases in males of other species, gonadal hormones suppress voluntary feed intake. for this reason, barrows, compared with gilts or boars, eat too much feed resulting in excessive fat deposition. Two experiments were performed in the present study to investigate the effects of implantation of Revalor H[Experiment(Exp.) I: 140mg trenbolone acetate(a synthetic androgen) + 14mg estradiol-$17\beta(E_{2}\beta)$] and Compudose(Exp. II; 24mg $E_{2}\beta$) on growth efficiency, carcass characteristics and circulating concentrations of IGF-I and IGF-binding protein-3(IGFBP-3). In Exp. I, sixty-four cross-bred finishing barrows weighing approximately 60kg were randomly divided into eight pens under a 2[control vs Revalor implant] $\times$ 2(ad libitum vs $80\%$ ad libitum feeding) $\times$2[control($103\%$ NRC-recommended level) vs low-energy($87\%$ NRC recommendation) diet] arrangement of treatments. In Exp. II, effects of Compudose were studied using 80 finishing barrows(10 animals/pen). In both Exps., all the animals were slaughtered at 100- to 110-kg body weight. Both Revalor and Compudose implants caused a decrease in feed intake and backfat thickness without affecting major physicochemical characteristics of the carcass and an increase in circulating IGF-I concentration. Moreover, Revalor implant exhibited greater effects than restricted feeding, low-energy diet, or Compudose in these variables. In addition, Revalor implantation suppressed weight gain, but enhanced the feed efficiency without exhibiting any interaction with the diet or feeding. In summary, results suggest that 1) both androgen and estrogen suppress voluntary feed intake and backfat deposition and enhance IGF-I secretion and 2) these effects of the gonadal steroid hormones in growth are likely to be mediated, in part, by IGF-I in finishing barrows.

• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.60-67
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• 2012

BACKGROUND: Anthracnose disease caused by Collectotrichum spp. is one of the most important worldwide devastating diseases in red pepper plants. Fungicides using plant extracts have several advantages, compared to synthetic chemical fungicides, because they are naturally occurring compounds, are usually safe for agricultural environment and are used for producing highly valuable agricultural products. Efforts for seeking an anti-fungal activities using naturally occurring compounds were mostly conducted from medicinal plant extracts. Sap of Rhus verniciflus was known to have healing effects on several human diseases. Recently, the extracts of Rhus verniciflus were actively tested for anti-cancer, anti-oxidative, and anti-fungal effects. In this study, the extract of Rhus verniciflus was tested for anti-fungal activity against Colletotrichum spp., which cause anthracnose in red-pepper. METHODS AND RESULTS: After neutralizing extracts of Rhus verniciflus (urushiol contents 70%) with autoclave, the crude extracts were used to investigate inhibitory effects for mycelial growth and spore germination of Colletotrichum spp. on PDA media. The mycelial growth and spore germination of Colletotrichum spp. were inhibited 18-39% and over 50% in response to crude extract of R. verniciflus (1.0 mg/mL). After spraying the extracts at the same concentrations above and then artificially inoculating Colletotrichum spp. on blue and red-pepper fruits, in vitro inhibition effects were examined. At 1.0 mg/mL, the crude extract of R. verniciflus showed inhibition activity in anthracnose incidence on blue- and red-pepper as 68.1-75.0%, through a artificial inoculation of Colletotrichum spp. in a laboratory. For in vivo inhibitory effects, the extracts (1.0, 0.1, and 0.01 mg/mL) were treated on red-pepper plants grown in green house 3 times at the interval of 1 week. Then inhibitory effects were determined by counting diseased fruits at 1 week after final treatment. The incidence of anthracnose was inhibited over 60% in the greenhouse by treatment of crude extract of R. verniciflus (1.0 mg/mL). CONCLUSION(s): Extracts of Rhus verniciflus were shown to have inhibitory effects on mycelial growth, spore germination of Colletotrichum spp. in vitro and on occurrence of anthracnose on pepper fruit in green house.

• Journal of Food Hygiene and Safety
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• v.18 no.3
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• pp.118-124
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• 2003

For the rapid detection of various pathogenic microorganisms from food sample, various kinds of kits have been developed and commercially available in the markets. With the advantages of speed, accuracy and easiness, the market of these kits has gradually increased for the QC and QA field of food company as well as testing facilities or laboratories. In this study, the characteristics such as the detection limit and the sensitivity of immunochromatographic type of rapid detection kit (Donga Co, Korea, D-kit) for E. coli 0157:H7 developed by monoclonal antibody were examined and also the possibility of application of the kit to food samples was evaluated. The reference kits used for comparison study were Reveal E. coli 0157:H7 (Neogen Co., USA, R-kit) and VIP EHEC kit (Biocontrol Inc., USA, V-kit) occupying major market share. In the detection limit test with the E. coli 0157:H7 reference, both R-kit and D-kit showed a distinct positive reaction in $10^4$/ml and weak positive reaction in $10^3$/ml, whereas V-kit showed a same reaction in 105/ml. Also, it was identified that the culture treated with heat showed more sensitivity than no heat treated culture. The sensitivity test was conducted against 22 isolates of E. coli 0157:H7, 7 strains of non-O157:H7 verotoxin-producing E. coli, 40 strains of E. coli with different O and H antigen type, and 38 strains of non-E. coli Enterobacteriaceae, and all of the test strains except three were showed exactly three were showed exactly the same reaction against three kinds of the tested kits. All the three kinds of kits showed a positive reaction against E. coli O157:H19, E. coli O148:H18 and Salmonella galinarium. We suppose that there might be a similarity in serological property between these three strains and O157:H7. From the test results, it can be concluded that there is (was) no difference between the D-kit developed in this study and R-kit or V-kit based on the detection limit and sensitivity.

• Journal of fish pathology
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• v.9 no.2
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• pp.185-193
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• 1996

Extensive acquirement of drug resistance to traditional antibacterial agents poses a serious problem to eel aquaculturists. To collect the basic information for new drug development in the future, we assessed the in vitro antibacterial efficacy of 14 new quinolones with 75 isolates of Edwardsiella tarda from local aquaculture tanks of Anguilla japonica. Of all tested quinolones under development or marketed for human use, DU-6859 was most potent with its $MIC_{50}$ value of $0.05{\mu}g$/ml in broth microdilution assay. The drugs whose $MIC_{50}$ values ranged from 0.2 to $0.78{\mu}g$/ml were T-3762, Bay-y3118, ciprofloxacin, norfloxacin, ofloxcin and tosufloxacin. The weakest group of drugs, with their $MIC_{50}$ being 1.56-$3.13{\mu}g$/ml, were difloxacin, sparfloxacin, fleroxacin, Q-35, amifloxacin, lomefloxacin and enoxacin. The number of resistant strains, when arbitrarily defined with their MICs of $\geq6.25{\mu}g$/ml, was : 3 to T-3762, 3 to Bay-y3118, 44 to difloxacin, 16 to sparfloxacin, 13 to ciprofloxacin, 19 to fleroxacin, 36 to Q-35). 31 to amifloxacin, 5 to norfloxacin, 13 to ofloxacin, 31 to lomefloxacin, 41 to enoxacin, 12 to tosufloxacin and 0% to DU-6859, respectively. This information can be taken into consideration for the future development of fisheries antibacterial quinolones.

• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.158-169
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• 2005

This study was done to evaluate the shear bond strength between light-cured glass ionomer cement (GIC) base and resin cement for luting indirect resin inlay and to observe bonding aspects which is produced at the interface between them by SEM. Two types of light cured GIC (Fuji II LC Improved, GC Co. Tokyo, Japan and Vitrebond$^{TM}$, 3M, Paul Minnesota U.S.A) were used in this study. For shear bond test, GIC specimens were made and immersed in 37$^{\circ}C$ distilled water for 1 hour, 24 hours, 1 week and 2 weeks. Eighty resin inlays were prepared with Artglass$^{(R)}$ (Heraeus Kultzer Germany) and luted with Variolink$^{(R)}$ II (Ivoclar Vivadent, Liechtenstein). Shear bond strength of each specimen was measured and fractured surface were examined. Statistical analysis was done with one-way ANOVA. Twenty four extracted human third molars were selected and Class II cavities were prepared and GIC based at axiopulpal lineangle. The specimens were immersed in 37$^{\circ}C$ distilled water for 1 hour, 24 hours, 1 week and 2 weeks. And then the resin inlays were luted to prepared teeth. The specimens were sectioned vertically with low speed saw. The bonding aspect of the specimens were observed by SEM (JSM-5400$^{(R)}$, Jeol, Tokyo, Japan) .There was no significant difference between the shear bond strength according to storage periods of light cured GIC base. And cohesive failure was mostly appeared in GIC On scanning electron micrograph, about 30 - 120 $\mu$m of the gaps were observed on the interface between GIC base and dentin. No gaps were observed on the interface between GTC and resin inlay.

• Journal of Gifted/Talented Education
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• v.14 no.2
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• pp.1-18
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• 2004

This study attempted to survey the present status of the eight students who, 17 years from now, had participated in a special program for 170 days preparing for early entrance to the KAIST. With six students who responded to the questionnaire previously sent, the study focused on each participant's achievement at present, his evaluation on Accelerated Education, his personal opinions on early entrance to university and Gifted Science Education. From the survey, we could find out that three participants had received a doctorate and they are currently working as researchers at research center or professors at university. The other three participants are working as researchers at research center after receiving the M. S. Academic achievements vary according to each participant, but three of them, who ranked high in research achievement, had their articles published in international journals of the SCI level even when they were between 25 and 28 of age. Two of them in particular showed outstanding engineering and developing the commercial modem for IMT 2000 for the first time in Korea. One participant entered Harvard University to major in physics and afterwards studied the law in UCLA. He is now a professor in the law department. Concerning the evaluations on Accelerated Education and early entrance system, four participants answered positively while two participants expressed negative attitudes. When asked their opinions on the Gifted Education in Korea, such problems were pointed out as too much pressure of entering the first-class universities, the tendency to avoid choosing science-related major at universities, the lack of education system that encourages creative thinking, etc. It is necessary that the accelerated education play an important role to maximize their hidden potentials. It remains to be seen in what places these six participants will find themselves and of what ideas they will come up within the next 17 years. It will be worthwhile to wait until then for another survey.