• Korean Journal of Optics and Photonics
• /
• v.33 no.2
• /
• pp.74-83
• /
• 2022

The entire process, from the raw material to the final system qualification test, has been developed to fabricate a large-diameter, lightweight reflective-telescope system for a satellite observation. The telescope with 3 anastigmatic mirrors has an aperture of 700 mm and a total mass of 66 kg. We baked a silicon carbide substrate body from a carbon preform using a reaction sintering method, and tested the structural and chemical properties, surface conditions, and crystal structure of the body. We developed the polishing and coating methods considering the mechanical and chemical properties of the silicon carbide (SiC) body, and we utilized a chemical-vapor-deposition method to deposit a dense SiC thin film more than 170 ㎛ thick on the mirror's surface, to preserve a highly reflective surface with excellent optical performance. After we made the SiC mirrors, we measured the wave-front error for various optical fields by assembling and aligning three mirrors and support structures. We conducted major space-environment tests for the components and final assembly by temperature-cycling tests and vibration-shock tests, in accordance with the qualifications for the space and launch environment. We confirmed that the final telescope achieves all of the target performance criteria.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.4
• /
• pp.551-559
• /
• 1996

To examine the effects of dietary fibers on gastrointestinal physiology, rats were fed with diets containing 10% sodium alginate,10% cellulose, or fiber-free diets for 5 weeks. The results obtained were as follows: The chronic consumption of sodium alginate induced a significant decrease in body weight gain and feeding efficiency, but a significant increase in length and weight of small intestine. Fecal bulk and weight were higher in fiber-fed group than fiber-free group. The chronic consumption of dietary fiber induced a significant increase in fecal output, resulting in tile decrease of apparent digestibility of protein and lipid. Pancreatic protease activity was lower in fiber-fed group than fiber-free group, whereas pancreatic amylase and lipase activities were not affected. Scanning electron microscopy(SEM) and light microscopy(LM) studies showed small intestine microvilli with numerous ridges and convolutions and goblet cells in fiber-fed groups. As a result of this study, it is concluded that the chronic consumption of dietary fiber decreases apparent digestibility of nutrients and induces morphological and biochemical adaptation of digestive organs.

• Journal of Nutrition and Health
• /
• v.25 no.6
• /
• pp.468-475
• /
• 1992

This study was carried out to observe the effects of dietaryn-6, n-3 fatty acids and vitamin A levels on humoral immunity in rat. Sixty eight male Sprague-Dawley rats were fed 6 different experimental diets for 6 weeks. The diets were composed of 10% of either corn oil or fish oil with various levels of vitamin A ; deficient(12450 IU/kg diet) adequate(4000IU/kg diet) and excess(400,000 IU/kg diet) The weight of spleen from the excess vitamin A-fish oil group showed the lowest value of all the groups when spleen weight was expressed/100g body weight. The number of PFC to SRBC was not affected by dietary at type and vitamin A levels. Hemagglutination titers were significantly lower in fish oil groups compared to corn oil groups and the values of vitamin A deficient groups were lower than the ones of adequate and excess vitamin A groups. IgM contents is serum were significantly lower in fish oil groups than in corn oil groups. IgG contents were higher in fish oil groups than in corn oil groups and the highest levels was recorded in excess vitamin A-fish oil group which showed the smallest speen size. Light microscopical examination showed that spleen tissues of fish oil groups were well developed than those of the corn oil groups and vitamin A deficient and excessive groups showed poor development than the adequate groups. Therefore it is suggested that adequate amounts of vitamin A consumption is necessary for healthy individuals and fish oil intake along with excess vitamin A should be avoided in order to maintain immune function properly.

• Journal of Sericultural and Entomological Science
• /
• v.29 no.1
• /
• pp.20-30
• /
• 1987

In the hemolymph proteins of the silkworm reared with mulberry leaves and artificial diet, electrophoretic patterns of Storege Protein 1 (SP1) and Vitellogenin(VG), changes of relative concentration of SP1, JHA effects during the developmental stages, and estimation of the molecular weight of vitellin subunits were investigated in the present study. 1. Storage Protein 1 (SP1) showed female specificity from the middle stage of the fifth instar to the end of spinning stage in the silkworm reared with mulberry leaves and artificial diet. 2. Vitellogenin (VG) showed female specififcity just afrter pupation in the silkworm reared with mulberry leaves and artificial diet. 3. Storage Protein 2 (SP2) without female specificity was detected from the early stage of the fifth instar to the first or second day after pupation. 4. Vitellin was composed of two non-identical subunits (vitellin-heavy chain ; VTL-H, vitellinlight chain ; VTL-L) with mplecular weight of 186,000 and 41,000. Also, there were no differenes between the molecular weights of vitellin subunits obtained from silkworms reared with mulberry leaves and artificial diet. 5. Relative concentration of Storage Protein 1 (SP1) after topical application - 0.5, and 10$\mu\textrm{g}$ per body weight - JHA on the 60th hour of the fifth instar showed the highest increase with the treatment of 5$\mu\textrm{g}$ and a higher increase with the treatment of 10$\mu\textrm{g}$ compared with the control (no topical application of JHA).

• Korean Journal of Poultry Science
• /
• v.47 no.3
• /
• pp.159-167
• /
• 2020

This study investigated the effect of different light sources in the poultry house on performance, meat quality, and blood composition of finishing broilers. Two hundred and forty male broilers (1-day-old, 42.2±0.1 g) were divided into three groups and subjected to different light source treatments (incandescent, LED, and fluorescent lamps) from 3 weeks of age (four replications/treatment, 20 birds/replication). After breeding for 6 weeks, the carcass yield and meat quality of broilers with similar body weight (BW; 3.4±0.07 kg) were investigated, and blood components were analyzed. Corn-soybean meal-based feed was provided as starter (CP 22.5%, ME 3,020 kcal/kg), early (CP 18.5%, ME 3,050 kcal/kg), and finishing (CP 18%, ME 3,100 kcal/kg). Performance, carcass yield, meat quality, and blood components were evaluated. BW, BW gain, feed intake, and feed conversion ratio did not show any significant differences among treatments. There was no significant difference on live weight and carcass yield among treatments. There was no significant difference on meat color, shear force, and water holding capacity; however, cooking loss at 17.2% was the highest in the LED treatment (P<0.05). There was no significant difference on blood components except for glucose (blood biochemistry component) among treatments. Glucose was 234.5 mg/dL, 256.9 mg/dL, and 250.1 mg/dL in the three treatments, respectively, with a significant difference between incandescent and LED treatments (P<0.05). These results are used useful as basic data for investigating the effect of lighting in broilers production.

• Korean journal of applied entomology
• /
• v.29 no.4
• /
• pp.257-268
• /
• 1990

The regional characteristics in the occurrence of the rice stem borer, Chilo suppressalis (Walker), in Korea, were examined by analyzing the light trap data obtained from 39 locations during the years of 1965-1988, and some ecological significance of the overwintering larval populations collected from the four locations where some of the typical ecological-race have been known, the results obtained are as follows; The total number of the moths have decreased greatly throughout the nation since 1970. The decrease in the total number of moths related with those in the spring moth but not in the summer moths, and suggested that the changes in the rice production systems have effected significantly on the second generation of the insect. The variations between the regions had been gret in 1960's, decreasing phase in 1970's and increasing phase in loast decade. The overall average of 50% emergence dates have shifted earlier in both moths, and the changes were different considerably with the regions as wheel as in generations. When the overwintered larvae were incubated at $25^{\circ}C$ and RH of 90%, the average mortalities were 21.07% for Suweon, 43.06% for Iri, 63.51% for Jinju, 27.04% for Gwangju. When the overwintered larvae were incubated at $25^{\circ}C$ and RH of 90%, the average mortalities were different with the body weight; 45.44% for the larvae of less than 39 mg, 37.61% for 40-49 mg, 37.28% for 50-59 mg, 30.17% for greater than 60 mg. When the overwintered larvae wee incubated at $25^{\circ}C$, post-diapause larval development periods of body weight classes were 18.6$\pm$1.2 days for the larvae of less than 39 mg, 20.4$\pm$3.3 days for 40-49 mg, 21.4$\pm$3.2 days for 50-59 mg, 21.8$\pm$3.2 days for grater than 60 mg, and only the larvae of less than 39 mg, body weight class less than 39 mg was found statistically different in post-diapause larval development periods. From these results, the changes in the cultural practice of the rice have effected on the ecological pattern of the rice stem borer, and the effects seemed to be different with the generations, and with the regions where the different ecological races are distributing.

• Korean Journal of Ichthyology
• /
• v.35 no.2
• /
• pp.91-100
• /
• 2023

The early life history of Silurus microdorsalis living in Jahocheon Stream was studied by observing egg and morphological development. Live fish were captured in June 2018, then reared in a circulating filtration system under a 14L : 10D photoperiod with a water temperature of 18℃. To artificially induce spawning, females were injected with 0.5 mL of Ovaprim (Syndel, Nanaimo, BC, Canada) per kg of body weight, and males were injected with 10,000 IU/kg body weight of human chorionic gonadotropin. Approximately 15 h later, eggs were artificially inseminated by the dry method. Mature eggs were light pale yellow, which separated them from immature eggs. Fertilized eggs were 2.16±0.06 mm (n=8) in diameter and fully hatched at 181 h after fertilization. The fertilization rate was 63.1±2.2%, and 10.0±3.7% of the embryos were malformed at 18℃. The rates of development were 181 h at 18℃, 109 h at 21℃, and 76 h at 24℃. The larval size immediately after hatching was 4.64±0.22 mm (n=8), and the larvae displayed negative phototaxis at 1 day after hatching. The total larval length on 7 days after hatching was 12.47±0.53 mm, with 25~30 basal anal fin rays and 14~16 basal caudal fin rays observed. The total larval length was 14.13±0.51 mm on 9 days after hatching, and approximately 90% of the black endoplasmic reticulum was deposited on the head and body. The dorsal fin had formed, and a single basal body was observed. On 15 days after hatching, the total larval length was 16.69±0.31 mm; the number of basal caudal fin rays (18 poles) was an integer because 2 dorsal fin basal rays and 60~63 anal fin basal rays were observed. The total larval length was 28.96±1.10 mm on 50 days after hatching; the numbers of caudal fins (n=18), dorsal fins (n=3), pectoral fins (n=11), and anal fin basal rays (n=67~73) were integers.

• Economic and Environmental Geology
• /
• v.19 no.spc
• /
• pp.121-130
• /
• 1986

In the Janggun mine, stannite occurs as anhedral grains, up to 500 micrometer in long dimension, closely associated with sphalerite, chalcopyrite, arsenopyrite, pyrrhotite, galena and rhodochrosite in the periphery of the South ore body. In reflected light, stannite is grayish yellow green in color and exhibits moderate bireflectance and strong anisotropism without any intenal reflections. Reflection; Rmax. =29.0, Rmin. =27.8 percent at a wavelength of 560nm, and VHN; 219~244kg/mm at a 50g load. The chemical composition on the average from 35 spot analyses by electron microprobe is, Cu 28.0, Fe 12.7, Zn 2.9, Mn 0.2, Sn 25.8, S 30.3, sum 99.9 (all in weight percent); the corresponding chemical formula as calculated on the basis of total atoms=8 is, Cu 1.88 Fe 0.97 Zn 0.19 Mn 0.02 Sn 0.93 S 4.01, which fulfills approximately the ideal formula of $Cu_2FeSnS_4$. The strongest reflections on the X-ray diffraction patterns are; $3.10{\AA}$ (10) (112), $2.72{\AA}$ (5) (020, 004), $1.922{\AA}$ (5) (024), $1.642{\AA}$ (3) (132), $1.244{\AA}$ (3) (143, 136, 235), $1.111{\AA}$(3) (244), $0.958{\AA}$ (1) (048, 422), the patterns are identical with those of literature. From the textural evidence of the microscopic observation, the mineral is considered to have been formed at the middle stage of hydrothermal lead-zinc-silver mineralization.

• Korean Journal of Human Ecology
• /
• v.22 no.4
• /
• pp.637-650
• /
• 2013

The purpose of this study was to examine the consumers' image and factors of wear comfort, expectation and satisfaction levels of wear comfort of hiking gear in order to investigate the consumer perception of wear comfort of hiking gear. The questionnaires were distributed to 400 people in their 40s and 50s and, 260 of which were used to data analysis. The questionnaires were comprised of questions about the image, factors, expectation and satisfaction levels of wear comfort of hiking gear, and demographic characteristics. Data were analyzed by frequency analysis, factor analysis, reliability analysis, correlation analysis, ANOVA, Duncan test, T-test with SPSS 19.0 IBM for Windows. In demographic characteristics, 43.5% of respondents were male and people under 45 years of age were at 17.7%, those between 46 and 50 with 46.5%, those between 51 and 55 with 28.9%, those between 56 and 60 with 6.9%. The results of this study are as follows. Responses of male and female consumers to image of wear comfort were similar and ten or more mentioned reponses by men were well-being and freedom from pain, stretchability, light weight, absorption of sweat, softness. Wear comfort of hiking gear was shown to include mobility/pressure factors, moisture factor, psychological factor, tactile/keeping body temperature factors. It was shown that the expectation and satisfaction levels of wear comfort of hiking gear were relatively high and were not influenced by consumer's sex and age, but were affected by the objective of mountaineering.

• Journal of Pharmacopuncture
• /
• v.17 no.2
• /
• pp.67-72
• /
• 2014

Objectives: This study evaluated the single-dose toxicity of Saeng Maek San (SMS) in rats. Methods: All experiments were conducted at Biotoxtech (Chungwon, Korea), an institute authorized to perform non-clinical studies under the regulations of Good Laboratory Practice (GLP). A single-dose intravenous toxicity study was carried out on 40 6-week-old Sprague-Daley rats. The animals were randomly divided into the following four groups of ten animals each: Group 1 (G1) was the control group, with each animal receiving an intravenous injection of 1.0 mL of saline, and Groups 2, 3 and 4 (G2, G3 and G4) were the experimental groups, with the animals in the groups receiving an injection of 0.1, 0.5 and 1.0 mL of SMS, respectively. Mortality, clinical signs, body-weight changes and gross pathological findings were observed for 14 days following a single administration of SMS or saline. Organ weights, clinical chemistry and hematology were analyzed at 14 days. This study was conducted with the approval of the Institutional Animal Ethics Committee. Results: No deaths occurred in any of the four groups, indicating that the lethal dose of SMS in rats is greater than 1.0 mL/animal. Some changes in weights of male rats between the control group and the experimental groups were observed, but no significant changes in the weights of female rats were noted. To identify abnormalities in organs and tissues, we stained representative sections of each specified organ with hematoxylin and eosin for examination with a light microscope. No significant abnormalities were observed in any of the organs or tissues. Conclusion: The results suggest that intravenous injection of SMS is a safe method of treatment.