• Korean Journal of Plant Resources
• /
• v.28 no.5
• /
• pp.656-664
• /
• 2015

To produce high quality watermelon, three tetraploid watermelon breeding lines (‘SA03-1’, ‘SA06-1’ and ‘SB01-1’) were developed by treatment with different chromosome doubling reagents. To identify the optimal tetraploid inductive conditions, the three watermelon breeding lines were selected by counting the number of doubled chloroplasts in guard cells. Tetraploid induction rates differed depending on the genotypes and treatment with doubling reagents. However, the highest induction rate occurred with 1.0% colchicine (82.2%). These putative tetraploid lines were re-confirmed for ploidy using flow cytometric analysis and chromosome counting. The internode length of the tetraploid breeding lines was different when the leaf size was larger in all three tetraploid lines compared to their diploids. The fruit weight of the tetraploid fruits for ‘SA03-1’ and ‘SB01-1’ was lower than for their diploid, and the rind thickness and total sugar content (°Brix) of tetraploid SB01-1 were significantly different from those of its diploid. Tetraploid lines were sterile, yielded a lower number of seeds per fruit for ‘SA03-1’ (21), ‘SA06-1’ (62), and ‘SB01-1’ (34.7), and the seeds were larger and thicker than those of their diploids. These tetraploid breeding results will be useful for breeding new seedless watermelon cultivars.

• Korean Journal of Microbiology
• /
• v.31 no.1
• /
• pp.1-8
• /
• 1993

lntergeneric hybrids formed between Aspergillus niger and Penicillium verruculosum were obtained by nuclear transfer technique. Nuclei isolated from wild type and auxotrophic mutants of donor strains were transferred into the protoplasts of different auxotrophic mutants as recipient strains. Several auxotrophic mutants were isolated from conidiospores of the two strains mutagenized with ultraviolet and N-methyl-N'-nitrosoguanidine. Optimal conditions for formation of intergeneric hybrids were investigated. Frequencies of intergeneric hybrid formation by nuclear transfer were $7{\times}10^{5}~1{\times}10^{5}$. From observations of genetic stability. DNA content. nuclear stain and conidial size. it was suggested that their karyotypes are aneuploid. In addition. the hybrids possess the 1.1~2.3-fold higher cellulase activities than those of parental strains. It was also revealed that some hybrids had different isozyme patterns compared to those of parental strains by CMCase and $\beta$-glucosidase activity assays.

• Microbiology and Biotechnology Letters
• /
• v.35 no.3
• /
• pp.231-237
• /
• 2007

To support the fermentational superiority of Korean nuruks and maintain the various domestic nuruks, the optimal nuruk production of Andong-Soju, which was designated as an intangible cultural asset of Gyungsangbukdo province from 1987, was investigated. Different thickness of nuruks ($2.2{\sim}5.5\;cm$) were manufactured based on traditional Andong-Soju nuruk method, while the size of round form of nuruk was set to 23 cm. During the 3 weeks maturation, changes of water content, weight, pH, brix, the amount of reducing sugar, sac-charifying activity, viable cell and major microorganisms were determined, Also, ethanol fermentation abilities of the manufactured nuruks were evaluated using 20% glucose medium or 16% starch medium, respectively. Our results indicated that the production of high quality of Andong-Soju nuruk needs $4.0{\sim}5.5\;cm$ thickness and 3 weeks maturation without extraneous yeast addition. These results would be applied to production of homogeneous, and high quality of Andong-Soju nuruk.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.3
• /
• pp.432-441
• /
• 1997

Stomach contents of fat greenling, Hexagrammos otakii were analyzed to understand feeding ecology of the fish in the coastal waters, Shinsudo, Sarhon. Specimens were collected by angling and by gill net from February 1984 to September 1985. The fish consisted of 4 age groups from 0 to 3. The food items of the fish changed slightly by seasons and with growth of the fish. Main preys were copepods, gammarids and caprellids for the fish of age group 0, gammarids and caprellids for age group 1, and brachyurans and carideans for age group 2 and 3. The prey composition of the fish were more varied by seasons than by ages. Food items was not different between male and female of the fish. The fish positively selected for gammarids, polychaetes and brachyurans, but negatively selected for gastropods. The degree of selectivities for the other preys were changed with growth. As the fish grows it consumed larger preys in case of small preys such as gammarids and caprellids, however, it did not consumed larger preys beyond an optimal size in case of large preys such as sphaeromids, brachyurans and polychaetes.

• Geophysics and Geophysical Exploration
• /
• v.10 no.3
• /
• pp.163-172
• /
• 2007

A seafloor curvature measurement method was developed to extract redundant topographic features from the multi-beam bathymetry data, and then applied to the data of abyssal plain area in the Pacific. Any seafloor might be modeled to a quadratic surface determined in a linear least squares sense, and its curvature could be derived from the eigen values related with quadratic model parameters. The curvature's magnitude as well as polarity showed distinct relationship with geometric characteristics of the seafloor like as ridge and valley. From the investigation of curvature's variation with the number of data in the quadratic surface, the optimal size of data aperture could be applied to real bathymetry data. The application to real data also required the determination of the accompanying threshold values to cope with corresponding topographic features. The calculation method of previous studies were reported to be sensitive to the background noise. The improved curvature measurement method, incorporating the sum of eigen values has reduced unwanted artifacts and enhanced ability to extract lineament features along strike direction. The result of application shows that the curvature measurement method is effective tool for the estimation of a possible mining area in the seamount free abyssal hill area.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.25 no.4
• /
• pp.166-171
• /
• 2015

In this study, using solid-state and flux, $Y_3Al_5O_{12}:Er^{3+}\;(YAG:Er^{3+})$ powders were successfully synthesized at low temperatures. To analyze the crystallinity of powders according to the synthesis or non-synthesis of powders and powder calcination temperatures, X-ray diffraction (XRD) was measured. In the case of pure YAG, when YAG was analyzed using the general solid-phase method, it was calcined for 12 hours at $1400^{\circ}C$ and pure YAG phase could be obtained. But when $BaF_2$ was added to YAG, YAG was synthesized at lower temperature (1000^{\circ}C$). It was thus found that the synthesis temperature could be lowered by about $400^{\circ}C$. Also, when BaF2 with an optimal concentration was added to $YAG:Er^{3+}$, the particle shape and size according to synthesis temperatures were surveyed, and corresponding luminous intensity was discussed.

• Composites Research
• /
• v.28 no.6
• /
• pp.395-401
• /
• 2015

This study investigated the thermal stability of Grubbs' catalyst and its reactivity with self-healing agents for self-healing damage repair. Four types of Grubbs' catalyst supplied by manufacturers were considered and each catalyst was tested in as-received and grinded conditions. Four types of self-healing agents were prepared by varying the mixing ratio of dicyclopentadiene (DCPD) and 5-ethylidene-2-norbonene (ENB). Heat flows as a function of temperature were measured through a differential scanning calorimetry (DSC) to determine the thermal stability of catalysts. Reaction heats of self-healing agents with the catalyst were measured to evaluate the reactivity of the catalyst. For this evaluation, Fluka Chemika Grubbs' catalyst was used based on the maximum temperature and the time to reach the maximum temperature. According to the results, catalysts had different shapes depending on the manufacturer and the results showed that the smaller the size of the catalyst the higher the reactivity with self-healing agents. As the ENB ratio in self-healing agents increased, the maximum temperature increased, and the time to reach the maximum temperature decreased. As the amount of the catalyst increased, the maximum temperature increased, and the time to reach the maximum temperature decreased. Considering the thermal stability of the catalyst and its reactivity with the self-healing agent, combination of 0.5 wt% catalyst and the D3E1 self-healing agent was optimal for self-healing damage repair. Finally, as the thermal decomposition may occur depending on the environmental temperature, the catalyst must not be exposed to temperature higher than that is necessary to maintain the thermal stability of the catalyst.

• Journal of Korean Society of Forest Science
• /
• v.108 no.4
• /
• pp.513-521
• /
• 2019

With rapid climate change and increasing global warming, the distribution of evergreen broad-leaved trees (EBLTs) is gradually expanding to the inland regions of Korea. The aim of the present study was to analyze the survival rate of 148 EBLT plantations measuring 180 ha and to determine the optimal plantation size that would help in coping with climate change in the warm, temperate climate zone of the Korean peninsula. For enhancing the reliability of our estimated survival model, we selected a set of 11 control variables that may have also influenced the survival rates of the EBLTs in the 148 plantations. The results of partial correlation analysis showed that the survival rate of 67.0±26.9 of the EBLTs in the initial plantation year was primarily correlated with plantation type by the crown closure of the upper story of the forest, wind exposure, and precipitation. For predicting the probability of survival by quantification theory, 148 plots were surveyed and analyzed with 11 environmental site factors. Survival rate was in the order of plantation type by the crown closure of upper story of the forest, wind exposure, total cumulative precipitation for two weeks prior to planting, and slope stiffness in the descending order of score range in the estimated survival model for the EBLTs with the fact that survival rate increased with shade rate of upper story to some extent.

• Journal of the Korean Home Economics Association
• /
• v.40 no.4
• /
• pp.167-178
• /
• 2002

This study was carried out to compare the meal management attitudes among the mothers(41 years of age) who had middle school students between in industrial complex and in non-industrial complex. The subjects of each group were composed of 192 mothers Living in Ansan city in Korea, and this study was performed by self-administered questionnaire. The results of the present study were as follows: (1) Monthly family income and education level of parents were lower in industrial complex-family(ICF) than in non-industrial complex-family (NICF). The mean age of mothers and family size were similar in two groups, but the frequency of mothers employed was higher in ICF than in NICF Most mothers in ICF worked as a manual- or skilled-laborer. (2) The mothers in ICF tended to have less positive attitude in sewing balanced meals to their families than those in NICF. The score of nutritional knowledge was lower in mothers in ICF than those in NICF. (3) The percentage of expense for purchasing staple foods to total expense of foods tended to be higher in ICF than in NICF. Engel's coefficient was higher, and the frequency and expense for eating out was lower in ICF than in NICF (4) The mothers in ICF did not try to use their time and energy efficiently for meal management. (5) The mothers in ICF were less active in sewing the pleasurable meals including the provision of various cooking methods, flavors, and temperatures, to their families, than those in NICF. Above findings show that family environment such as industrial complex-families and non-industrial complex-families influences the meal management attitudes of mothers. The mothers in ICF had a less positive altitudes for scientific meal managements than those in NICF even though they had the limited resources including money, time and energy for meal management because most mothers in ICF had a job that were paid low salary and finished irregularly or late. Therefore, these results underscore the need to provide the sound nutritional education for the mothers in ICF with respect to reasonable meal management for 'optimal nutrition of family'. In addition, the government should try to make the various welfare policies to improve nutritional status of low income famines including the poor industrial complex-families.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.2
• /
• pp.141-151
• /
• 2013

The nano-surface modification techniques could be classified; internal modifications which enhance surface roughness and porosity in nano level and external modifications as nano particle coating. Nano-modified implant surface has various morphograpies such as nanotube, nanopit, nanonodule and polymorphic structures. Creating surface depends upon preparation method and material, however, there is no standard preparation technique not yet. The nano-modified surfacet is electrochemically stable comparing with the surface modified in micron level. Nano-modified surface has little cytotoxicity, stimulates osteoblast proliferation and differentiation. Moreover, it decreases soft tissue intervention by interrupting the proliferation of fibroblast. Nanostructure has similar size and shape with cells and proteins, consequently leads to good biocompatibility and enhanced osseointegration. However, the actual effect in vivo is limited, due to the distance of effect. Even if nano-modified surface has antibiotic property due to photocatalysis, short duration time makes clinical application questionable. Further investigations should focus on the optimal nano-modified surface, which has many potentials.