• Journal of Korean Society of Forest Science
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• v.110 no.1
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• pp.64-71
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• 2021

Recently, climate change has gradually accelerated the occurrence of landslides. Among the various effects caused by landslides,debris flow is recognized as particularly threatening because of its high speed and propagating distance. In this study, the impacts of various factors were analyzed using quantification theory(I) for the prediction of debris flow hazard soil volume in Seoraksan National Park, Korea. According to the range using the stepwise regression analysis, the order of impact factors was as follows: vertical slope (0.9676), cross slope (0.6876), altitude (0.2356), slope gradient (0.1590), and aspect (0.1364). The extent of the normalized score using the five-factor categories was 0 to 2.1864, with the median score being 1.0932. The prediction criteria for debris flow occurrence based on the normalized score were divided into four grades: class I, >1.6399; class II, 1.0932-1.6398; class III, 0.5466-1.0931; and class IV, <0.5465. Predictions of debris flow occurrence appeared to be relatively accurate (86.3%) for classes I and II. Therefore, the prediction criteria for debris flow will be useful for judging the dangerousness of slopes.

• Korean Journal of Ichthyology
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• v.28 no.1
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• pp.35-40
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• 2016

The microhabitat of Iksookimia hugowolfeldi was surveyed in two sites, Geogeum Island and Jangheung. I. hugowolfeldi in Geogeum Island inhabits mainly pool. This water system consists of sand and cobble and has a shallow water (0.1~0.8 m depth) with slow currents (0.1 m/s). 0+ years old inhabits pool consist of sand and lives in a less than 0.3 m depth. I. hugowolfeldi in Jangheung population inhabits mainly pool consists of sand and cobble and lives in a shallow water (0.1~0.8 m depth) with slow currents (0.1 m/s) compared to the stream of Geogeum Island. With some different fish species, sympatric species collected at Geogeum Island and Jangheung population are 7 species in 4 family identically in the two sites.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.2
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• pp.93-98
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• 2010

Bumblebees are widely used to pollinate various crops, especially tomato, in greenhouses and fields. An artificial hibernation is essential for year-round rearing of the bumblebee, which passes through one generation per year. Here, we investigated whether a chilling temperature and humidity affect artificial hibernation of the bumblebee queen Bombus terrestris. In chilling temperature regimes of $0^{\circ}C$, $2.5^{\circ}C$, $5^{\circ}C$, $7.5^{\circ}C$ or $12.5^{\circ}C$ under constant humidity >70%, the queens stored at $2.5^{\circ}C$ exhibited the highest rate of survival, which was 74.0% at one month, 67.0% at two months, 60.0% at three months, 46.0% at 4 months, 33.0% at 5 months, and 24.0% at 6 months. Rates of survival decreased at the following temperatures: $0^{\circ}C$, $5^{\circ}C$, $7.5^{\circ}C$ and $12.5^{\circ}C$. Colony developmental characteristics after diapause were 1.2- to 1.5-fold higher than those of queens stored at $5^{\circ}C$. In terms of chilling humidity, the queens hibernated at 70% under $2.5^{\circ}C$ exhibited the highest rate of survival, which was $93.3{\pm}3.4%$ at one month, $83.3{\pm}0.0%$ at two months, $76.7{\pm}0.0%$ at 3 months and $36.7{\pm}12.1%$ at 5 months. The rates of oviposition, colony foundation and progeny-queen production of queens hibernated at 70% were 80.8%, 30.8% and 30.8%, respectively. These values correspond to 1.7- to 3.3-fold increases in comparison to queens stored at 50% humidity. Therefore, $2.5^{\circ}C$ and 70% R.H. were the favorable chilling temperature and humidity conditions for diapause break of B. terrestris queens.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.4
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• pp.267-271
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• 2000

A total of 1,830 soybean collections were grown in the field and characterized for 10 morphological traits to determine the diversity and relationship within and among geographical regions. Phenotypic variation was found within all regions for most characters. The Shannon-Weaver diversity index ranged from 0.49 to 0.62 across regions, and 0.09 to 1.00 across characters. Canonical discriminant analysis and clustering of the canonical means delineated 3 regional clusters: (ⅰ) Kyunggi, Chungchong, Kangwon, Chulla, and Kyungsang; (ⅱ) Heilongjiang; and (ⅲ) Jilin, Manchuria, central China, south China, Others (China), Hokkaido, Honshu, and Others (Japan).

• Korean Journal of Materials Research
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• v.16 no.6
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• pp.351-354
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• 2006

[ $Co_{1-x}Fe_xSb_3$ ] skutterudites were synthesized by encapsulated induction melting and their thermoelectric properties were investigated. Single phase ${\delta}-CoSb_3$ was successfully obtained by the subsequent heat treatment at 773 K for 24 hours in vacuum. However, ${\delta}-CoSb_3$ was decomposed to FeSb2 and Sb when $x{\leq}0.3$, which means that the solubility limit of Fe to Co is x<0.3. The positive signs of Seebeck coefficients for all Fe-doped specimens revealed that Fe atoms acted as p-type dopants by substituting Co atoms. Thermoelectric properties were remarkably enhanced by Fe doping and optimum composition was found to be $Co_{0.7}Fe_{0.3}Sb_3$ in this study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.5
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• pp.539-543
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• 1992

This study was carried out to investigate the antimutagenic affect of crude and heated comfrey extract on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), benzo${(\alpha)}$pyrene (B${(\alpha)}$P) and 3-amino-1, 4-dimethyl-5H-pyri-do [4,3-b] indole (Trp-P-1). In spore rec-assay using Bacillus subtilis $H17(rec^+)$ and $M45(rec^-),$ crude comfrey extract showed strong antimutagenic effects on MNNG in the concentration of $40{\mu}l/disc$(p<0.01). In the Ames test using Salmonella typhimurium TA98 and TA100, the crude comfrey extract suppressed about 43% and 52% in the mutagenesis induced by $B{(\alpha)}P.$ However, the heated comfrey extract strongly suppressed about 75% and 76% in the mutagenesis in Salmonella typhimurium TA98 and TA100 induced by Trp-P-1(p<0.01).

• Journal of Biosystems Engineering
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• v.35 no.3
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• pp.151-157
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• 2010

The objective of this study was to analyze the factors affecting on fuel consumption of agricultural tractor. According to the statistical analysis, fuel consumption of agricultural tractor was considerably influenced by kind of operation, throttle engine speed and gear steps of tractor but much less by kind of soil. Specific fuel consumption of the tractor in plowing, dry paddy tilling, wet paddy tilling and wet paddy levelling was 0.33~0.36, 0.30~0.45, 0.19~0.34, 0.28~0.39 L/$kW{\cdot}h$, respectively, and $CO_2$ emission was 0.36~0.45, 0.35~0.58, 0.22~0.42, 0.24~0.37 kg/$kW{\cdot}h$, respectively. Specific fuel consumption and $CO_2$ emission increased as throttle engine speed increased but reversely proportional with gear step of tractor, by which one can reduce fuel consumption and $CO_2$ emission with practicing of "Gear up & Throttle Down" technique in paddy operations.

• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.213-219
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• 2013

This study focused on the promotion of the insecticidal activity of eco-friendly insecticidal materials against four major insect pest in the organic Chinese cabbage cultivation area. Among insecticidal materials mixture, BT+Matrine+Neem against leaf beetle larva, Phaedon brassicae, showed the highest 94.1% at 0.05% which is the lowest concentration of three treated concentrations. The insecticidal activity of Matrine, Neem, and BT alone (0.1%, w/v) or the mixtures (0.05%, w/v) against Cabbage worm larva, Artogeria rapae, was investigated by leaf disc spray method. The insecticidal efficacy of the mixtures of two or three eco-friendly materials was higher than the single treatment of each material with 94.3%, 100% and 100%. Control efficacy of 0.3% COY+0.05% (95.3%) against the green peach aphid, Myzus persicae was higher than that of 0.3% COY+0.05% Neem (90.2%) and lasted for more than 21 days after one time treatment. At 35 days after treatment, the effect of 0.05% BT+0.05% Matrine and 0.05% BT+0.05% Matrine+0.05% Neem treatments against diamondback moth showed very high insecticidal activity with more than 90% of control value. Therefore, BT, Neem, and Matrine where are properly treated could be effective eco-friendly materials for controlling major insect pests in an organic Chinese cabbage field.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.431-440
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• 2022

Hanwoo cattle are a unique and historical breed in Korea that have been genetically improved and maintained by the national evaluation and selection system. The aim of this study was to provide information that can help improve the accuracy of the estimated breeding values in Hanwoo cattle by showing the difference between the imputation reference chip platforms of genomic data and the scaling factor of the genetic relationship matrix (GRM). In this study, nine sets of data were compared that consisted of 3 reference platforms each with 3 different scaling factors (-0.5, 0 and 0.5). The evaluation was performed using MTG2.0 with nine different GRMs for the same number of genotyped animals, pedigree, and phenotype data. A five multi-trait model was used for the evaluation in this study which is the same model used in the national evaluation system. Our results show that the Hanwoo custom v1 platform is the best option for all traits, providing a mean accuracy improvement by 0.1 - 0.3%. In the case of the scaling factor, regardless of the imputation chip platform, a setting of -1 resulted in a better accuracy increased by 0.5 to 1.6% compared to the other scaling factors. In conclusion, this study revealed that Hanwoo custom v1 used as the imputation reference chip platform and a scaling factor of -0.5 can improve the accuracy of the estimated breeding value in the Hanwoo population. This information could help to improve the current evaluation system.

• Journal of the Korean Society of Food Culture
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• v.15 no.3
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• pp.195-199
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• 2000

Varied levels of mannitol at 0%, 3%, 6% and 9% were added to the commercial orange juice and physicochemical and sensory characteristics of the juice were investigated. Refractive index of control had $11.3^{\circ}Bx$ and the index was significantly increased to that of the $18.4^{\circ}Bx$ as the addition was increased to the 9% level(p<0.05). The values of pH and the acidity did not show significant differences among varied levels of mannitol added samples. However, sensory characteristics of aroma and sweet flavor were significantly increased as the addition levels were increased showing the values of aroma, from 7.5 to 11.3, and those of sweet flavor from 5.0 to 11.9, respectively (p<0.05). The 9% added level sample had significantly the lowest sour and astringent flavor values of 4.0 and 2.3, respectively.