• 한국전자파학회논문지
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• 제21권4호
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• pp.371-380
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• 2010

CATR(Compact Antenna Test Range)은 실내에서 반사판을 사용하여 균일 평면파를 제공하는 시험 시설이다. 반사판의 가장자리에서 발생되는 회절 전계는 균일 평면파의 리플(ripple)을 증가시키는 요인이 되기 때문에 CATR에서는 서레이션(serration)을 반사판의 가장자리에 부착하여 균일 평면파의 리플을 낮추게 된다. 일반적으로 서레이션의 회절 전계는 이중 적분으로 표현되는 프레넬 회절식(Fresnel diffraction formula)을 사용하여 해석하고, 서레이션 구조는 프레넬 회절식의 이중 적분 영역에 적용시키기 위해 푸리에 급수로 표현한다. 본 논문에서 는 새로운 shark-fin 형태를 갖는 서레이션을 사용하였고, 제안된 서레이션에 인접한 서레이션의 높이에 차이를 주는 구조를 제안하였다. 기존 삼각형 구조의 서레이션과 새로운 shark-fin 구조의 서레이션을 비교하여 제안한 shark-fin 구조의 서레이션에서 quiet zone의 크기를 보다 넓힐 수 있음을 확인하였고, 인접 서레이션의 높이에 변화를 주었을 때 동일한 높이보다 리플이 낮아짐을 확인하였다. 따라서 본 논문에서 제안한 shark-fin 형태의 높이가 다른 서레이션 구조는 CATR의 시험 영역에 리플이 낮은 균일 평면파를 제공할 수 있을 것으로 생각된다.

• 한국치위생학회지
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• 제12권3호
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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.

• 한국식품과학회지
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• 제47권2호
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• pp.145-148
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• 2015

메타규산나트륨은 우리나라 식품첨가물공전에 등록되어 있는 품목으로 식용유지류의 여과보조제의 목적 이외에는 사용할 수 없으며, 최종식품 완성 전에 제거하도록 규정되어 있다. 그러나 최근 샥스핀 등 수산물에 중량 증량의 목적으로 메타규산나트륨을 불법 사용하는 사례가 지속적으로 발생함에 따라 메타규산나트륨의 사용 여부를 판별할 수 있는 분석법의 필요성이 대두되고 있다. 그러나 메타규산나트륨의 수용액은 강알칼리성용액으로 식품에 첨가되면 해리되어 그 자체로 분석할 수 없으며, 규소 양의 측정을 통해 간접적인 방법으로 추정할 경우 시료 자체에 천연적으로 존재하는 규소와 구분해야 하는 어려움이 있다. 따라서 본 연구에서는 메타규산나트륨의 첨가 여부를 판별하기 위한 기초 자료 확보를 위해 메타규산나트륨 수용액에 가공되지 않은 상어지느러미를 침지하여 중량의 증가, pH 및 규소 함량 변화를 측정하였고, 이를 모니터링 결과와 비교하였다. 그러나 Robberecht 등(7)의 연구결과 6종의 어류에서 규소가 1.77-84.19 mg/kg의 범위에서 검출된 결과에서 알 수 있듯이, 수산물의 종류와 개체 간에 규소 함량의 편차가 크게 나타날 수 있기 때문에 향후 샥스핀의 규소 함량 모니터링을 지속적으로 수행하여 데이터베이스를 좀 더 보강할 필요가 있을 것으로 판단되며, 그 이후에 대조군과 pH, 수분 및 규소 함량 비교를 통해 메타규산나트륨 사용여부를 유추해 볼 수 있을 것으로 생각된다.

• 수산해양기술연구
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• 제43권4호
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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.

• 한국수산과학회지
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• 제42권2호
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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%.

• 한국어류학회지
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• 제26권4호
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• pp.336-339
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• 2014

우리나라 남부연안에서 채집된 1개체 (전장 350.0 mm)의 표본을 근거로 흉상어과에 속하는 Scoliodon laticaudus를 한국미기록종으로 기재 보고한다. 본 종은 머리가 매우 납작한 삽모양이며 주둥이가 길고 납작한 점 가슴지느러미가 삼각형이며 제 1 등지느러미 후단이 배지느러미 중앙부분까지 도달하는 특징이 있다. 본 속과 종의 신한국명으로 각각 "납작주둥이상어속"과 "납작주둥이상어"를 제안한다.

• Fisheries and Aquatic Sciences
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• 제27권8호
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• pp.515-524
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• 2024

The high economic value and demand for shark fin have significantly increased the vulnerability of the shortfin mako shark (Isurus oxyrinchus Rafinesque, 1810) population in the Indian Ocean, particularly in the southern region of Java and West Nusa Tenggara. This study utilized a length-based assessment method to evaluate the stock status of I. oxyrinchus. Over a span of eight years (2013-2021), data on length frequency and sex composition were collected. The length-based spawning potential ratio (SPR) was employed to investigate the stock status of the fishery. The findings revealed that I. oxyrinchus exhibited a large body size, with an asymptotic length estimated at 386.86 cm total length and a growth coefficient of 0.04/year . Females were more frequently captured than males, and evidence indicated a declining trend in the size of female sharks. A low SPR value of approximately 6% indicated the overfishing condition of mako shark. To ensure the sustainability of the shortfin mako shark population in the Indian Ocean, it is essential to develop effective management strategies through integrated cooperation among the government, fishers, traders, shark industries, and local communities.

• 한국어류학회지
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• 제27권1호
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• pp.45-49
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• 2015

돔발상어목 Somniosidae에 속하는 Somniosus pacificus 1개체가 2008년 2월 강원도 강릉해역에서 채집되었다. 본 종은 두 등지느러미 사이의 길이가 주둥이에서 첫 번째 새열까지의 길이보다 짧으며, 주둥이에서 첫 번째 등지느러미 사이의 길이가 전장의 45%를 넘고 몸은 전체적으로 잿빛을 띠는 특징을 가진다. 우리나라에서 처음 보고되는 본 종의 새로운 과명, 속명 및 종명으로 "잠상어과", "잠상어속" 및 "잿빛잠상어"를 제안한다.

• Animal Systematics, Evolution and Diversity
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• 제14권1호
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• pp.43-49
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• 1998

1996년부터 1997년까지 서해와 제주도를 비롯한 국내 연안에서 채집된 흉상 어속 어류를 재검토한 결과 Carcharhinus brachyurus, C. dussumieri, C. limbatus, C. plumbeus, C. sorrah의 5종이 분류되었으며, 이 가운데 Carcharhinus dussumieri 흰뺨상어와 C. sorrah 검은꼬리상어는 미기록종으로 확인되었다. 흰뺨상어는 제2등지느러미만 검은색을 띠고, 검은꼬리상어는 꼬리지느러미 하엽과 제2등지느러미, 가슴지느러미 끝에 뚜렷한 검은색을 띠고 있어서 무태상어, 흉상어 등 국내의 기타 흉상어속 어류와 잘 구분되었다. 한편 정(1977)의 C. gangeticus와 C.bracyurus는 각각 C. plumbeus와 C. limbatus임이 명백하였으며, C. limbatus에 대해서는 국명을 남방상어로 하였다.

• 산업기술연구
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• 제36권
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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.