• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.371-380
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• 2010

The CATR(Compact Antenna Test Range) is a testing facility which is to provide the uniform plane wave by using the reflector. As the ripple of the uniform plane wave caused by the diffraction rays at the edge of the reflector, serrations are attached at the edge of the reflector to minimize the ripple of the uniform plane wave in the CATR. The diffraction field of the serration is normally analyzed by the Fresnel diffraction formula which is expressed as the double integration, and the structure of the serration is expressed as Fourier series to apply the double integration of the Fresnel diffraction formula. In this paper, the novel shark-fin shaped serrations which have the height modulation of the adjacent serrations are proposed. And the triangular serrations and the novel shark-fin shaped serrations are compared to confirm that the performance of the quiet zone by the shark-fin shaped serrations is better than by the triangular serrations. It is also confirmed that the novel shark-fin shaped serrations which have the height modulation of the adjacent serrations are lower ripple than which have the same height of the adjacent serrations. Accordingly, the novel shark-fin shaped serrations with the height modulation can be used at the edge of the reflector to provide the uniform plane wave in CATR.

• Journal of Korean society of Dental Hygiene
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• v.12 no.3
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• pp.513-520
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• 2012

Objectives : In this study, contact angle and shore D hardness were measured, and a shark fin test was conducted after selecting five addition silicon(Blu-Mousse, BM; EXABITE II, EX; PERFECT, PF; Regisil$^{(R)}$ Rigid, RE; Silagum$^{(R)}$, SI) in order to figure out the properties of elastomeric interocclusal recording materials and reduce errors at interocclusal recording. 8) Methods : A contact angle was measured using a contact angle analyzer. After placing a drop of liquid on the surface of the specimens of interocclusal recording materials, a contact angle was photographed with a CCD camera on the equipment. In terms of a shark fin test, interocclusal recording materials were mixed for the time proposed by the manufacturer and inserted into the split ring of the Shark fin device. Twenty (20) seconds exactly, a metal rod was removed to make the materials slowly absorbed. Once they hardened, fin height was measured with a caliper after separating molds and trimming the specimens. The shore D hardness was measured with a shore D hardness tester(Model HPDSD, Hans Schmidt & Co. Gmbh, Germany) in sixty (60) minutes after fabricating specimens. In each experiment, five specimens, mean and standard deviation were calculated. A one-way ANOVA test was performed at the p>0.05 level of significance. In terms of correlation among the tests, Pearson correlation coefficient was estimated. For multiple comparison, Scheffe's test was carried out. Results : A contact angle was the highest in EX with $99.23^{\circ}$ (p<0.05) while the result of the shark fin test was the longest in RE with 5.45mm. SI was the lowest (0.27mm) with statistical significance. Among the interocclusal recording materials, significant difference was observed in terms of means (p<0.05). The shore D hardness was the highest in SI with 31.0 while RE was significantly low with 16.4 (p<0.05). Among the materials, statistically significant difference was observed in terms of means when compared to the rest materials (RE), BM, RE and SI (PF and EX) and the remaining materials (BM and SI) (p<0.05). In terms of correlations among the tests, a negative correlation occurred between shore D hardness and shark fin test(r=-0.823, p=0.000). Conclusions : According to the study above, it is necessary to understand the properties of interocclusal recording materials and consider contact angle, shark fin test and properties of shore D hardness to select appropriate materials.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.145-148
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• 2015

According to the Korea Food Additives Code, sodium metasilicate is permitted for use as a filtering agent for edible oils and fats. Sodium metasilicate is currently used as a food additives to increase the weight of shark fins. In this study, we developed an analytical method to quantify sodium metasilicate in food. Sodium metasilicate content was estimated by measuring the moisture content, pH and silicon content of shark fins. Silicon content was analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES) following microwave-assisted digestion with $HNO_3$ (65%) and $H_2O_2$ (30%). Shark fin total silicon content was $7.17{\pm}8.92mg/kg$, while the soluble silicon content was $2.34{\pm}3.80mg/kg$. After soaking raw shark fin in an aqueous solution of sodium metasilicate, fin weight, pH and silicon content were measured. These results would be used as the basic information for shark fins safety management.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.4
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• pp.329-338
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• 2007

Data collected by on-board observers and from experimental surveys during 2004-2006 were analyzed to figure out the status of shark bycatch in Korean tuna longline fishery. Results obtained from 10 surveys indicated that 14, 13 and 1 species of shark were incidentally caught in Korean tuna longline fishery operated in the Pacific, Indian and Atlantic (Mediterranean) Ocean, respectively, and that shark bycatch accounted for about 29-31% of the total catch. Sharks brought aboard were processed in 3 ways; out of 1,127 sharks observed, 575 sharks (51.0%) were discarded after finning, 299 sharks (26.5%) were stored frozen after finning for future use and 253 sharks (22.4%) were released into the sea immediately after caught. The fin to body weight ratio of sharks was estimated to be about 4.7% which is similar to the guideline of 5% established by the international fisheries organizations. The underestimate of shark bycatch in Korean tuna longline fishery was significant because it was general practice that fishermen on-board did not count the discarded shark as a catch.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.2
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• pp.157-164
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• 2009

The National Fisheries Research and Development Institute (NFRDI) conducted a circle hook experiment to compare the catch rates of target and bycatch species between J hook and circle hooks in the tuna longline fishery of the Eastern Pacific Ocean, which is located between $9^{\circ}13'S-1^{\circ}36'N$ and $126^{\circ}00'-138^{\circ}21'W$. Sampling was conducted from September 20 to October 23, in 2006. In this survey, we collected shark data to obtain the ratio of fin weight to body weight of sharks. Overall, 413 sharks belonging to 9 species were caught on 62,464 hooks. The total weight of the sharks caught was 11,093 kg. The ratio of wet fin weight to body round weight of sharks by species ranged from 3.7% to 7.7%, while the mean was 5.4%. The total ratio of wet fin weight to the dry fin weight of sharks ranged 0.38 to 0.70 and the mean value was 0.53. The ratio of dry fin weight to the body round weight of the sharks was estimated to be 2.86%.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.336-339
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• 2014

The spadenose shark, Scoliodon laticaudus, belongs to the family carcharhinidae was described as the first record from Korea based on a single specimen collected from the South Sea of Korea. The species is characterized by having a greatly depressed and trowel-shaped head, a depressed and long snout, triangular pectoral fins, and posterior tip of the first dorsal fin reaching the middle of pelvic fin. We propose a new Korean names of the genus Scoliodon and the species S. laticaudus as "Nab-jag-ju-dung-i-sang-eo sog" and "Nab-jag-ju-dung-i-sang-eo", respectively.

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.45-49
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• 2015

A single specimen (192 cm total length, TL) of the Pacific sleeper shark, Somniosus pacificus, belonging to the family Somniosidae, order Squaliformes, was firstly collected from the west margin of the East Sea, Korea in February 2008. This specimen was characterized by having interdorsal space, being less than the distance between the snout and first gill opening; and the distance between the snout and first dorsal fin origin more than 45% TL; head and body has overall dark brownish. The new Korean name "Jam-sang-eo-gwa" is proposed for the family Somniosidae, and "Jam-sang-eo-sok" for the genus Somniosus, and "Jat-bit-jam-sang-eo" for the species S. pacificus.

• Animal Systematics, Evolution and Diversity
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• v.14 no.1
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• pp.43-49
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• 1998

The taxonomic revision of the genus Carcharhinus in Korea was made based on the shark specimens collected in the western and southern coasts including Cheju Isl. of Korea from July 1996 to April 1997. Five species were recognized from the Korean waters and they are described herein. Among them, two species of Carcharhinus dussumieri (Valenciennes, 1839) and Carcharhinus sorrah (Valenciennes, 1839) were collected for the first time from the Cheju Isl. coast of Korea. Carcharhinus dussumieri differs from other species of genus Carcharhinus in following morphological characters: a black or dark spot on the sencond dorsal fin but no other markings, a small first triangular dorsal fin and a second dorsal fin with a short inner margin, and Carcharhinus sorrah: conspicuous black tips on the ventral caudal lobe, pectoral and second dorsal fins, and low second dorsal with a inner margin.

• Journal of Industrial Technology
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• v.36
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• pp.39-43
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• 2016

The purpose of this study is to determine and compare the mechanical and flow properties of polyvinylsiloxane impression pastes. Twelve polyvinylsiloxane impression materials were used. As mechanical properties, tensile strength and tear resistance were measured. Impression materials are subjected to tensile stresses when they are removed from the oral cavity and from stone models and tear resistance is the ability of the material to resist tearing under a tensile stress. Flow is dependent on the ability of the material to resist shear forces. Flow tests were performed to determine the handling characteristics and was measured using a shark fin testing device. An impression material must be able to penetrate the narrow subgingival sulcus and tight interproximal areas. Therefore, it must be able to resist the shear forces as it is pushed between tooth and gingival walls. It is necessary to understand the properties of interocclusal recording materials and is considered that the results obtained in this study will provide guideline information for the manufacturing of impression materials and for selecting appropriate impression materials.

• Korean journal of food and cookery science
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• v.26 no.5
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• pp.521-529
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• 2010

The purpose of this study was to research healthy food behavior and food recognition for each Asian country after subjects had visited Asian restaurants. The subjects of the study were university students from Griffith university and Queensland university, Australia. The survey was conducted from June 1 to 28, 2010. The summary of the analysis is as follows. Firstly, for dietary behavior related to healthy food, 'average' was the most common answer at 41.0% (102 respondents). Regarding the standard of selecting healthy food, 'if it is good for health' was the most common answer, regarding the reasons to like healthy food, 'because it is good for health', was the most common, and for information about healthy food, 'obtain from TV or media' was the most common. Regarding eating healthy food at home or dining out, most respondents answered 'once or twice a week', whereas regarding thinking of eating healthy food while dining out, 'average' was the most common answer. Secondly, the recognition of six Asian cuisines were ranked in the order of Chinese, Japanese, Korean, Thai, Indian, and Vietnamese. Representative well-being food by country, Bibimbap of Korea, Sushi of Japan, Shark's Fin of China, Tom Yum Kung of Thailand, Curry of India and Goi Cuon of Vietnam were selected. Thirdly, regarding recognition of well-being food, disease effect factor, health-oriented factor, nutrition factor and vegetarian diet factor were extracted. We found that disease effect factor and nutrition factor had positive (+) effects on visiting Asian restaurants due to recognition of well-being foods. Therefore, it is expected that more local people will eat at Asian restaurants if the public relations for Asian restaurants emphasizes harmony between well-being food and Asian food.