A model net experiment of the gape net for anchovy in Jindo, Jeollanam-do was carried out to investigate the net shape and hydrodynamic resistance using circulating water channel. The model net was made 1/33 down scale by Tauti’s similarity method and the range of experimental current speed was from 0.5 knot to 3.5 knot (increasing 0.5 knot interval). The net mouth height in 0.5 knot of the minimum experiment current speed was shown 26.0 cm (full-scale conversion value 8.58 m). The net mouth height and mouth area in 1.5 knot of the same current speed with a gape net fishing ground were shown 20.0 cm (full-scale conversion value : 6.60 m) and about 507.9 cm2 (full-scale conversion value : 55.31 m2). The net mouth height and area were decreased with increase the experimental current speed. The hydrodynamic resistance of the model net in 1.5 knot current speed was shown 1.11 kgf and the value of full-scale conversion by Tauti’s method was shown 3.996 ton.

The heat treatment machine based on immersion was developed to reduce temperature difference during netting process and appraised it performance compared current heat treatment machine using high pressure. It was also reviewed the optimum heat treatment procedures for PBSAT monofilament net in accordance with the immersion time and temperature. The procedure was based on physical measurement such as breaking load, elongation and angle of the mesh for PBSAT monofilament. The water temperature gap of the treatment machine based on immersion was less than 1°C. and the energy consumption was also increased in high temperature condition. It was identified that the optimum temperature was 75°C and its optimum processing time was between 15 minutes and 20 minutes to get qualified physical properties.

Swelling of the heat-treated netting for gillnet was estimated through the netting height in square acrylic tank. Experimental Nylon netting and PBSAT netting were heat-treated by using the high-degree vacuum method in hot water after net making. Heat-treatment temperatures were conducted with Nylon netting 105°C and PBSAT netting 62°C, 65°C, 66°C, 67°C. The swelling measurement method of a netting using the square tank was capable of the reduction measurement errors comparing with measurement methods of a mesh inner angle and the shortening rate of a mesh size. In addition, this method was available to comparison evaluation for each netting more easily. Wet type heat-treatment apparatus with high-degree vacuum was shown higher 7∼8°C inner side temperature than a setting temperature. The tensile strength and elongation of Nylon netting and PBSAT netting were shown higher wet condition than dry condition. The tensile strengths of PBSAT monofilaments in dry and wet condition were sharply decreased at heat-treatment temp. 75°C than heat-treatment temp. 74°C

Bleeding from pancreatic pseudocyst is a rare complication. Furthermore, massive upper gastrointestinal (GI) bleeding from gastro-cystic fistula formation and intracystic bleeding are both extremely rare and are also potentially fatal. A 53-year-old male was referred to the emergency room with melena and hematemesis. An urgent endoscopy revealed a massive gastric hematoma but showed no specific bleeding focus. Gastrocystic fistula formation and intracystic bleeding leakage to the stomach were suspicious in the follow-up endoscopy. A contrast-enhanced computed tomography scan demonstrated splenic artery pseudoaneurysm and extravasation of contrast media into the cyst that was abutted to the greater curvature side of the stomach. A splenic artery embolization was performed and no further bleeding occurred after embolization. Upper GI bleeding from gastro-cystic fistula and intracystic bleeding are rare but possible. Therefore, this possibility should be considered in the unknown cause of an upper GI bleeding in a patient with pancreatic pseudocyst.

Physical characteristics of PA (Polyamide) gill net and biodegradable gill net made by PBS (Polybutylene succinate) (mesh size 63mm, mesh thickness number 2, 2.5, 3) were analyzed to investigate catching efficiency of the biodegradable gill net for Pacific herring. Total 11 numbers of catching efficiency tests were carried out using commercial fishing vessel at Imwon port in Kangwon province from May to June 2013. The amount of catches were 1,535.7kg (18 species) through the catching efficiency tests and it is expected that the practicalization of biodegradable gillnet is possible because there is no difference for catches between PA gillnet and PBS gillnet. Catches of herring according to the thickness of net twine was the highest at No.2 and the thicker net twine tends to decrease the catches.

우리나라 일반국도의 도로포장은 아스팔트 포장으로 이루어져있으며, 2011년 말을 기준으로 총연장 13,739km으로 전체 도로연장 중 약 13%를 차지하는 105,931km이다. 도로포장구간의 연장은 13,459km로써 약 97.6%의 포장률을 나타내고 있다. 최근 지구온난화와 기상이변 등의 전세계적인 기후변화에 따라 연평균기온 및 해수면 상승, 폭우 및 폭풍 등과 같은 환경영향으로 국제적으로 저탄소 녹색혁신 기술의 수요가 증가하고 있다. 따라서 본 연구에서는 기존 일반국도 아스팔트 포장 구간의 포장보다 시공시 온도, 카본 다이옥사이드 가스, 유해가스, 석유계 연료, 유해 증기, 분진 등을 저감하고, 시공 후 양생시간을 감소시키며, 공용온도에서 가열 아스팔트 포장과 비슷한 강도 특성을 확보하는 저탄소 중온 아스팔트를 이용한 시공을 할때, 교통량 검지기 (NC97)를 사용하여 도로교통에 대한 특성을 조사하였다. 본 연구를 통해서 그림 2와 같이, 공사중의 차량 속도는 공사전과 비교하여 평균 -13km/h의 차이가 있으며, 오전 첨두시는 -9km/h, 오후 첨두시 -24km/h의 속도 차이가 발생하였다. 특히 저탄소 중온 아스팔트 포장의 시공중 교통량이 가장 많은 오후 첨두시 pm5:00~pm6:00인 시점에서 가장 많은 속도 차이(-26km/h) 특성을 보였으며, 일반적인 아스팔트 포장의 공사시보다 단축된 도로점용 공사시간 및 조기개방으로 인한 교통지정체 비용 및 탄소배출량이 저감되었을 것으로 예측된다. 하지만, 명확한 저탄소 중온 아스팔트 포장의 시공으로 인한 편익 추정을 위하여 향후 경제성분석, 탄소배출 저감량, 교통에 미치는 영향 등의 연구가 필요할 것으로 사료된다.

The objective of this study is to estimate the optimal net twine thickness of drift net for yellow croaker. The filed experiments of the fishing performance were conducted with three kinds of drift net with different monofilament diameters (No.3=0.284mm, No.4=0.330mm, No.5=0.370mm) the total eight times in the southwest coastal sea of Korea. And the physical properties tests on the monofilaments of experimental net were carried out to estimated breaking load and softness in dry and wet conditions, respectively. From the results, the No.3 mono. was the strongest break load per unit area in dry and wet conditions. And the softness showed that the No. 3 mono. was the most soft than another experimental monofilaments. The fishing performance was; the No. 3 drift net showed the most catches. Conversely, the catches of No. 4 and No. 5 drift net showed the half on the catches of No. 3 drift net. Consequently, the diameter of monofilament in the drift net for yellow croaker should carefully choose to consider the economic sides such as the amount of catches and the cost of catches.

Physical characteristics of net filament were investigated to test the fishing capacity of gill nets due to the flexibility difference between nylon and biodegradable nets (PBS 95%+PBAT 5% and PBS 80%+PBAT 20%). In addition, a total of 16 fishing experiments were conducted in the coastal waters of Jeongja, Ulsan, from August 10 to October 20, 2011 and from September 11 to November 3, 2012. The test results showed that nylon net filament exhibited more flexibility than biodegradable net filament when they were wet. Accordingly, the longer submerged time, the more fishing capacity the nylon gill nets demonstrated in comparison with the biodegradable gill nets. A total of 16 species were caught in 2011 with the nylon gill nets (1,323 fishes, weighing 342,885g) and the biodegradable gill nets (958 fishes, weighing 236,857g). 15 species were caught in 2012 with the nylon gill nets (1,582 fishes, weighing 448,360g) and the biodegradable gill nets (1,431 fishes, weighing 406,590g). Thus catch weights and the number of fish caught produced by the nylon nets were 1.45 times and 1.38 times higher than those of the biodegradable nets produced in 2011, and 1.1 times and 1.11 times higher in 2012. A test on the target species, pointhead flounder (Cleisthenes pinetorum) has similar results. The flexibility of a net was proved to be related to the fishing capacity, and as a result, it is concluded that the higher flexibility, the higher fishing capacity.

Biodegradable octopus pot was developed to reduce plastic pollution problem in the sea and fishing trouble between fishermen. It can be expect to recycle other wasted biodegrade fishing gear. Experimental fishing was carried out to understand the difference in fishing efficiency between Polyethylene (PE) octopus pots and biodegradable (Polybutylene Succinate and Polybutylene adipate-co-terephthalate) octopus pots which was tried to make in this study in the sea. There were caught by 237 numbers of fishing during the experimental period. Among the 237 numbers of fishing, 160 or 67.5% were PE pots which were more than the biodegradable pots. A comparison of the monthly catches between the PE pots and biodegradable pots shows that the catches were overall higher in the PE pots than in the other pots. The result is very similar with the comparison of total catches by each type of the pots. In terms of bycatch, the number of species, amount of catches and the number of fishing with bycatch were more significant in the biodegradable pots than in the PE pots.

This study was aimed not only to develop the gill net and trap made of biodegradable monofilaments in order to prevent a ghost fishing and to protect marine ecosystem, but also to analyze their spinning process and physical properties. Results showed that the spinning speed of biodegradable polybutylene succinate(PBS) monofilament was estimated to be approximately 100m/min when spinning temperature and cooling water temperature were adjusted at 180℃ and 3℃, respectively. The breaking loads of PBS monofilaments were estimated to be 35.3kg/mm2 at Φ0.2mm, 46.5kg/mm2 at Φ0.3mm, and 49.7kg/mm2 at Φ0.4mm in the dry condition, respectively. However, its breaking loads in the wet condition were reduced by 2.4-5.5%, compared to those in the dry condition. The knotted strength of PBS monofilament at Φ0.2mm was estimated to be 98.6% of PE in the dry condition. The breaking load of PBS monofilament at Φ0.3mm was evaluated to be 81.8% of PA, and its softness showed 3 times less than that of PA in the wet condition. The breaking load of PBS monofilament at Φ0.4mm was 95.3% of PA, and its softness showed 1.6 times less than that of PA in the wet state. However, the load elastic elongations of two kinds of monofilaments were estimated to be 1% higher than that of PA.

In order to develop the biodegradable monofilament gill net for the protection of marine ecosystem and reduction of ghost fishing, enpol monofilament gill net was made for Chionoecetes opilio using polybutylene succinate as a biodegradable chip. Catching efficiency on 2 type monofilament gill net, PA and Enpol, were carried out using 2 commercial fishing boats around the fishing ground of Wang-dol rock from January 2004 to May 2006. Enpol monofilament gill net spun polybutylene succinate as a biodegradable chip was appeared high practicality for Chionoecetes opilio gill net. Target fishing ratio were 98% and 98.3% for the PA and enpol monfilament gill net, respectively. In addition, CPUE ratio of female and male(CL < 90mm) to Chionoecetes opilio caught in the enpol gill net were 25.3-40.3%, 14.0-22.1% less than PA gill net, respectively. However, CPUE ratio of male(CL > 90mm) to Chionoecetes opilio caught in the enpol gill net were 2.5-11.3% more than PA gill net. There was no difference in CPUE of female and male to Chionoecetes opilio caught using 2 gill nets as a result of the significance level of 5% by T-test.

본 연구는 COVID-19로 인한 온라인 개학 상황에서 진행된 학교현장실습의 문제점과 이를 초래한 영향 요인들을 심층적으로 분석하는 것을 목적으로 수행되었다. 이를 위해 2020년도 1학기에 학교현장실습을 진행한 학생 8명과, 지도교사 2명을 대상으로 면담을 진행하였다. 연구 결과 학교 현장실습에서 학생들이 경험한 문제점들은 주로 온라인 개학이라는 새로운 상황적 특성(예컨대 학생 없이 진행된 온라인 수업 참관과 시연, 비정상적인 수업 시연에 대한 교사 피드백의 유용성 저하, 온라인 개학 하에서의 학생 관리 및 상담 등 실무경험에서의 근본적 한계, 위기 상황 속에서 교사들의 업무 부담 가중)에서 비롯된 것들이 대부분이었다. 하지만 이러한 문제점들은 실습학교와 지도교사의 온라인 수업과 학교 운영에 대한 준비 정도가 미흡할수록 더욱 증폭되어 나타났고, 특히 기존 연구를 통해 지속적으로 지적되어 왔던 해묵은 원인들(예컨대 짧은 실습기간, 교원양성 기관과 실습학교 간의 의사소통과 협력 관계 형성 미흡, 학교현장실습의 구성 및 운영방식에 대한 정부/교육청 차원의 구체적 지침 미비, 실습 지도 교사의 역량과 관심에 전적으로 좌우되는 실습의 질 등)이 재난 상황을 계기로 더욱 증폭되어 나타나는 것임을 알 수 있었다. 이러한 연구 결과를 바탕으로 연구자들은 향후 온라인 개학 중 학교현장실습을 보다 효과적으로 시행하기 위한 몇 가지 고려사항들을 제언으로 제시하였다.

울릉도에서 산출되는 치밀한 회색부석, 회색부석, 갈색 및 검은색부석의 기질에 대한 광물 암석학적 특성을 연구하기 위하여 X-선 회절분석, FT-IR, 열분석, XRF, SEM 분석을 실시하였다. 그 결과, 울릉도 부석의 기질은 전반적으로 비정질이며 미량의 새니딘과 아노르도클레이스의 결정구조적 특성을 보였다. FT-IR 흡수스펙트럼에서 흡착수분을 지시하는 O-H 피크가 관찰되었으나 열분석에서 나타나지 않는 것으로 보아 수분 함량은 미미한 수준인 것으로 판단된다. 이러한 낮은 수분 함량은 기질이 넓은 비표면적을 가지며 형성 이후 상당한 시간이 지났음에도 불구하고 수화변질 정도를 매우 낮게 만든 것으로 생각된다. SEM 이미지상에서 기질의 기공은 2~2000μm 크기를 가지며 구형, 타원형, 실타래형 및 각상의 형태학적 특성을 보인다. 또한, 기공들은 융합하고 성장하면서 변형되는 연성특성을 보여준다. 다양한 크기와 형태를 보이는 기공의 특성은 마그마의 급격한 압력감소와 빠른 냉각에 기인하며 형성과정에서 마그마가 상당한 연성을 유지하였음을 시사한다. 초기에 형성된 치밀한 회색부석은 기공의 성장이 제한되고 구형 기공의 결핍과 각상의 매우 작은 기공(15μm 이하)을 포함하는 것으로 보아 수화프리니언 분출에 근접하였음을 시사한다. 기질표변에서 관찰되는 비정질 알루미나 규산염 덩어리인 극미립질 입자는 알칼리계열의 포놀라이트질 마그마가 급격히 상승하는 과정에서 미립자화된 마그마가 기질표면에 부착된 것으로 판단되며 부분적으로 결정화된 알칼리 장석입자와 공존할 가능성이 높은 것으로 추정된다.

Fifty hydrocarbon-metabolizing microorganisms were isolated from soil samples polluted by the petroleum oils in Gamman-dong, Busan. Among them, strain 2-3A, showing strong emulsification activity, was selected by oil film-collapsing method. This bacterium was identified as Acinetobacter sp. and designated as Acinetobacter sp. 2-3A. The optimum temperature and pH on the growth of Acinetobacter sp. 2-3A were 25℃ and pH 7.0, respectively. The carbon and nitrogen sources for the most effective emulsification activity were 3.0% olive oil and 0.5% peptone, respectively. The 0.15% potassium phosphate was the most effective emulsification activity as a phosphate source. The optimum emulsification activity condition was 20℃, pH 7.0, and 2.0% NaCl. The optimum time for the best production of biosurfactant was 27 hrs. The emulsification stability was maintained at the temperature range from 4℃ to 100℃, pH range from 6.0 to 10.0, and NaCl range from 0% to 10%. For the oil resolvability of the biosurfactant, the residual oils were investigated by gas chromatography. As a result, it was verified that the biosurfactant decreased and decomposed crude oils from nC10 to nC32.