• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.1
• /
• pp.52.1-52.1
• /
• 2021

We present the results of multi-epoch, multi-frequency monitoring of a blazar 4C +29.45, which was regularly monitored as part of the Interferometric Monitoring of GAmma-ray Bright AGNs program - a key science program of the Korean Very long baseline interferometry Network (KVN). Observations were conducted simultaneously at 22, 43, 86 and 129 GHz during the 4 years from December 2012 to December 2016. We also used additional data from the 15 GHz Owens Valley Radio Observatory (OVRO) monitoring program. From the 15 GHz light curve, we estimated the variability time scales of the source during several radio flux enhancements. We found that the source experiencesd 6 radio flux enhancements with variability time scales of 9-187 days during the observing period, yielding corresponding variability Doppler factors of 9-27. From the multi-frequency simultaneous KVN observations, we were able to obtain accurate radio spectra of the source and hence to more precisely measure the turnover frequencies 𝜈_r of synchrotron self-absorbed (SSA) emission with a mean value of ${\bar{\nu}_r}=28.9GHz$. Using jet geometry assumptions, we estimated the size of the emitting region at the turnover frequency. Taking into account these results, we found that the equipartition magnetic field strength is up to two orders of magnitudes higher than the SSA magnetic field strength (0.6-99 mG). This is consistent with the source being particle dominated.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.7
• /
• pp.95-102
• /
• 2023

The purpose of this study was to investigate the effect of 8 weeks of core training on dynamic posture control, lower extremity injury and proprioceptive joint position sensory in ski athletes. Twenty subjects participated in this study and were randomly divided into two groups : exercise group (Ex=10) and control group (Con=10). The core training program consisted of a bench, a sideways bench, a plank, a side bridge, and a supine bridge, and was conducted three times a week for 8 week. The dynamic posture control had a significant effect on the left and right postero-medial reach, and the lower extremity criterion test had a significant effect on the left and right composite scores. In addition, there was a significant decrease in the proprioceptive joint position sense at 15°of the left leg and 45°. In conclusion, 8 weeks a core training have been shown to improve skiers' dynamic posture control, lower extremity injury and proprioceptive joint position sensory.

• Korean Journal of Food Science and Technology
• /
• v.30 no.2
• /
• pp.341-347
• /
• 1998

To develop simple and accurate analytical method for freezing time prediction of beef and tylose under various freezing conditions, freezing time (Y) was regressed against the reciprocal $(X_3)$ of difference of initial freezing point and freezing medium temperature, reciprocal $(X_4)$ of surface heat transfer coefficient, the initial temperature $(X_1)$ and thickness $(X_2)$ of samples which should cover most situations arising in frozen food industry. As results of the multiple regression analysis, equations were obtained as follows. $Y_{tylose}=3.45X_1+7642.84X_2+4642.67X_3+2946.89X_4-431.33\;(R^2=0.9568)$ and $Y_{beef}=0.68X_1+7568.98X_2+2430.78X_3+3293.26X_4-299.00\;(R^2=0.9897)$. These equations offered better results than Plank, Nagaoka and Pham's models, shown in satisfactory agreement with models of Cleland & Earle and Hung & Thompson when were compared to previous models, and the accuracy of its was very high as average absolute difference of about 10% in the difference between the fitted and experimental results. Also, thermal diffusivities of beef and tylose were measured as $4.43{\times}10^{-4}m^2/hr$ and $4.39{\times}10^{-4}m^2/hr$ at $6{\sim}7^{\circ}C$, $2.42{\times}10^{-3}m^2/hr$ and $3.32{\times}10^{-3}m^2/hr$ at $-10{\sim}-12^{\circ}C$. Initial freezing points of beef and tylose were $-1.2^{\circ}C\;and\;-0.6^{\circ}C$, respectively. Surface heat transfer coefficients were estimated $20.57\;W/m^2^{\circ}C$ with no-packing, $16.11\;W/m^2^{\circ}C$ with wrap packing and $13.07\;W/m^2^{\circ}C$ with Al-foil packing, and the cooling rate of immersion freezing method was about 10 times faster than that of air blast freezing method.

• Journal of Bio-Environment Control
• /
• v.4 no.2
• /
• pp.136-143
• /
• 1995

Using a PEG- dextran two phase partition method, plasma and intracellular membrane separated from microsomal membrane of canola (Brassica napus) leaves have been fractionated by centrifugation. $K^{+}$- ATPase specific activity in the plasma membrane (U$_2$ phase) of plants grown at $25^{\circ}C$ and 1$0^{\circ}C$ were 6.6 and 4.6 times, respectively that of the microsomal membrane. Plasma membrane had a lower cytochrome- c- oxidase specific activity than the microsomal membrane or intracellular membrane, while intracellular membrane (L$_2$ phase) had a high cytochrome-c- oxidase but little $K^{+}$- ATPase specific activity. The plasma membrane of canola grown at 1$0^{\circ}C$ had higher 18:3 to 18:2 (linolenic to linoleic acid) ratio (29.2% ) and higher degree of unsaturation than that grown at $25^{\circ}C$ The double bond index of plasma membrane from canola grown at 1$0^{\circ}C$ increased by 8.9% relative to canola grown at $25^{\circ}C$. Similar, intracellular membrane increased by 19.7% at 1$0^{\circ}C$. Canola grown at 1$0^{\circ}C$ was lower in chlorophyll contents (17.3%) than that grown at $25^{\circ}C$. These changes in fatty acid unsaturation were attributable largely to change in Cl8 fatty acid, with major changes occurring in linolenic acid (18 :3) which might have a physiological role of membrane to adaptation on low temperature.ure.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.15 no.1
• /
• pp.47-51
• /
• 1982

Red tilapia fingerlings were tested for 45 days on the growth rate in a closed recirculating water system omitting filter bed and was compared with common carp fingerlings grown together in the same tank and also with red tilapia fingerlings grown in a well conditioned conventional pond. The tank water was kept in deepgreen colour by heavy phytoplankton bloom during the most of the experimental period and duckweeds, Lemna sp. and water hyacinth, Eichhornia crassipes were put to grow in the parts of the water system. Total ammonia level in the tank was mostly kept at about 5 to 7 ppm, with a fluctuation between 3.4 and 11.2 ppm. Average daily growth rate of the tilapia in the experimental tank was $6.5112\%$ without any mortality, compared to $3.617\%$ for common carp fingerlings involving some mortality in the same tank, and to $5.7712\%$ for the tilapia grown in the conventional pond. The feed used for the experiment was one prepared for the rearing of common carp, and the duckweed grown in parts of the water system was routinely collected and fed to the tilapia in the tank as supplementary diet probably satisfying unknown growth factors.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.11
• /
• pp.771-776
• /
• 2020

In this study, the flexural/shear behavior characteristics of perfobond FRP-concrete composite beams using an FRP plate with perforated webs as formwork and reinforcement are analyzed through an analytical method. Compared with the existing experimental results, we have proved its usefulness and use it in future practice. When the nonlinearity is very large in this case, the nonlinear finite element analysis by an explicit method will be effective. The concrete damage plasticity (CDP) model adopted in this study is considered to be able to adequately simulate the nonlinear behavior of concrete, and the determination of several variable factors required in the model is compared with the experimental results and values used in the study. This recommendation will require review and adjustment for more diverse cases. The effect of the perfobond of the composite beam with perforated web is considered to be somewhat effective in terms of securing the initial stiffness, but in the case of the apex, it is considered that the cross-sectional loss and the effect of improving the bonding force should be properly arranged. The contact problem, such as slipping of the FRP plate and concrete, is considered to be one of the reasons that the initial stiffness is slightly larger than the test result, and the slightly difference from the experimental results is attributed to the separation problem between concrete and FRP after the peak.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.2
• /
• pp.192-197
• /
• 1999

Proximate composition, sterol and $\alpha$-tocopherol ($\alpha$-Toc) contents of 35 species of marine invertebrates (13 species of Bivalvia, 10 species of Gastropoda, 4 species of Cephalopoda, 4 species of Crustacea, 2 species of Ascidacea and 2 species of Holothuroidea), which caught off the coast of Tongyeong of the Southern sea (Nam-Hae), Korea, were determined. Protein content showed relatively high level in herbivorous (seaweed feeder) and carnivorous species such as Gastropoda ($17.2\pm4.30\%$), Crustacea ($16.8\pm4.06\%$) and Cephalopoda ($15.3\pm3.24\%$), but showed low in plankton feeder and mud swallow such as Bivalvia ($11.8\pm2.49\%$), Ascidacea ($8.20\pm1.00\%$) and Holothuroidea ($3.94\pm1.13\%$). Total lipid (TL) content was low in most marine invertebrates, ranged from $0.24\%$ (blue colored sea cucumbers) to $1.96\%$ (sea squirts). Ascidacea contained the largest amount of TL in all samples, while Holothuroidea contained the smallest amount of TL, and other classes contained about $1\%$ of TL. Carbohydrates was rich in plankton feeder and Herbivorous species (seaweed feeder) such as Ascidacea ($6.60\pm4.53\%$), Bivalvia ($3.15\pm1.82\%$) and Gastropoda ($3.02\pm1.61\%$), while poor in carnivorous species such as Crustacea ($0.52\pm0.57\%$) and Cephalopoda ($1.00\pm0.63\%$). Moisture content was highest in Holothuroidea ($92.0\pm1.94\%$) and the lowest in Gastropoda ($77.0\pm1.95\%$): There were negative correlations between moisture and protein content, or TL, between protein and TL content; y= -0.8716x+184.452 (r=-0.87, p<0.001), $y=128.52e^{-0.0601x}$ (r=-0.55, P<0.001), $y=6.3047e^{-0.0904x}$(r=-0.42, P<0.02), respectively. Sterol content was ranged from 56 mg/100 g edible portion of red colored sea cucumbers to 216 mg/100 g edible portion of cockle and was high in the following order; Cephalopoda (148 $\pm$30.0mg)>Bivalvia (121$\pm$35.0mg)>Gastropoda (118$\pm$20.0mg)>Crustacea (116$\pm$31.0mg)>Ascidacea (78.0$\pm$2.00 mg)>Holothuroidea(62.0$\pm$8.00 mg). Crustacea contained 1$\~$2 mg $\alpha$-Toc/100 g edible portion whereas other classes contained trace or less than 1 mg/100 g of edible portion.

• Journal of Nutrition and Health
• /
• v.8 no.1
• /
• pp.15-37
• /
• 1975

I. Subject of the study A study on the nutritive value and utilization of powdered seaweeds. II. Purpose and Importance of the study A. In Korea the shortage of food will be inevitable by the rapidly growing population. It will be very important study to develop a new food from the seaweeds which were not used hitherto for human consumption. B. The several kinds of seaweeds have been used by man in Korea mainly as side-dishes. However, a properly powdered seaweed will enable itself to be a good supplement or mixture to certain cereal flours. C. By adding the powdered seaweed to any cereals which have long been staple foods in this country the two fold benefits; saving of cereals and change of dietary pattern, will be secured. III. Objects and scope of the study A. Objects of the study The objects will come under four items. 1. To develop a powdered seaweed as a new food from the seaweeds which have been not used for human consumption. 2. To evaluate the nutritional quality of the products the analysis for chemical composition and animal feeding experiment will be conducted. 3. Experimental cocking and accepability test will be conducted for the powdered products to evaluate the value as food stuff. 4. Sanitary test and also economical analysis will be conducted for the powdered products. B. Scope of the study 1. Production of seaweed powders Sargassum fulvellum growing in eastern coast and Sargassum patens C.A. in southern coast were used as the material for the powders. These algae, which have been not used for human consumption, were pulverized through the processes of washing, drying, pulverization, etc. 2. Nutritional experiments a. Chemical composition Proximate components (water, protein, fat, cellulose, sugar, ash, salt), minerals (calcium, phosphorus, iron, iodine), vitamins (A, $B_1,\;B_2$ niacin, C) and amino acids were analyzed for the seaweed powders. b. Animal feeding experiment Weaning 160 rats (80 male and 80 female rats) were used as experimental animals, dividing them into 16 groups, 10 rats each group. Each group was fed for 12 weeks on cereal diet (Wheat flour, rice powder, barley powder, potato powder, corn flour) with the supplementary levels of 5%, 10%, 15%, 20% and 30% of the seaweed powder. After the feeding the growth, feed efficiency ratio, protain efficiency ratio and ,organs weights were checked and urine analysis, feces analysis and serum analysis were also conducted. 3. Experimental cooking and acceptability test a. Several basic studies were conducted to find the characteristics of the seaweed powder. b. 17 kinds of Korean dishes and 9 kinds of foreign dishes were prepared with cereal flours (wheat, rice, barley, potato, corn) with the supplementary levels of 5%, 10%, 15%, 20% and 30% of the seaweed powder. c. Acceptability test for the dishes was conducted according to plank's Form. 4. Sanitary test The heavy metals (Cd, Pb, As, Hg) in the seaweed powders were determined. 5. Economical analysis The retail price of the seaweed powder was compared with those of other cereals in the market. And also economical analysis was made from the nutritional point of view, calculating the body weight gained in grams per unit price of each feeding diet. IV. Results of the study and the suggestion for application A. Chemical composition 1. There is no any big difference in proximate components between powders of Sargassum fulvellum in eastern coast and Sargassum patens C.A. in southern coast. Seasonal difference is also not significant. Higher levels of protein, cellulose, ash and salt were found in the powders compared with common cereal foods. 2. The levels of calcium (Ca) and iron (Fe) in the powders were significantly higher than common cereal foods and also rich in iodine (I). Existence of vitamin A and vitamin C in the Powders is different point from cereal foods. Vitamin $B_1\;and\;B_2$ are also relatively rich in the powders.'Vitamin A in ·Sargassum fulvellum is high and the levels of some minerals and vitamins are seemed4 to be some influenced by seasons. 3. In the amino acid composition methionine, isoleucine, Iysine and valine are limiting amino acids. The protein qualities of Sargassum fulvellum and Sargassum patens C.A. are seemed to be .almost same and generally ·good. Seasonal difference in amino acid composition was found. B. Animal feeding experiment 1. The best growth was found at.10% supplemental level of the seaweed Powder and lower growth rate was shown at 30% level. 2. It was shown that 15% supplemental level of the Seaweed powder seems to fulfil, to some extent the mineral requirement of the animals. 3. No any changes were found in organs development except that, in kidney, there found decreasing in weight by increasing the supplemental level of the seaweed powder. 4. There is no any significant changes in nitrogen retention, serum cholesterol, serum calcium and urinary calcium in each supplemental level of the seaweed powder. 5. In animal feeding experiment it was concluded that $5%{\sim}15%$ levels supplementation of the seaweed powder are possible. C. Experimental cooking and acceptability test 1. The seaweed powder showed to be utilized more excellently in foreign cookings than in Korean cookings. Higher supplemental level of seaweed was passible in foreign cookings. 2. Hae-Jo-Kang and Jeon-Byung were more excellent than Song-Pyun, wheat cake, Soo-Je-Bee and wheat noodle. Hae-Je-Kang was excellent in its quality even as high as 5% supplemental level. 3. The higher levels of supplementation were used the more sticky cooking products were obtained. Song-Pyun and wheat cake were palatable and lustrous in 2% supplementation level. 4. In drop cookie the higher levels of supplementation, the more crisp product was obtained, compared with other cookies. 5. Corn cake, thin rice gruel, rice gruel and potato Jeon-Byung were more excellent in their quality than potato Man-Doo and potato noodle. Corn cake, thin rice gruel and rice gruel were excellent even as high as 5% supplementation level. 6. In several cooking Porducts some seaweed-oder was perceived in case of 3% or more levels of supplementation. This may be much diminished by the use of proper condiments. D. Sanitary test It seems that there is no any heavy metals (Cd, Pb, As, Hg) problem in these seaweed Powders in case these Powders are used as supplements to any cereal flours E. Economical analysis The price of the seaweed powder is lower than those of other cereals and that may be more lowered when mass production of the seaweed powder is made in future. The supplement of the seaweed powder to any cereals is also economical with the criterion of animal growth rate. F. It is recommended that these seaweed powders should be developed and used as supplement to any cereal flours or used as other food material. By doing so, both saving of cereals and improvement of individual's nutrition will greatly be achieved. It is also recommended that the feeding experiment for men would be conducted in future.