• 수산해양기술연구
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• 제44권3호
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• pp.184-193
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• 2008

For environment-friendly fishery, the lead sinkers of octopus drift line were developed with the environmentfriendly sinker, and their characteristics and performance were investigated. To make the environmentfriendly sinker, the hydrate ceramic material was developed, and to increase the weight and strength, the iron power was added to it. The fishing hook was machine-made, and standardized, by using 60cm iron wire. For the manufacture of the sinker, the first, the mold was made, and then, hydrate ceramic material and water were quantitatively mixed. The mixture was poured into the mold prepared with a fishing hook already inserted, and had hardened for several hour, before it was taken out of the mold as a complete sinker. The sinkers were made in the 8 types ranging in weight from 150 to 500g, and their specific gravities were diverse from 2.871 to 6.637, which was 0.19 to 0.44 times lower than that of lead. The movement of the environment-friendly sinker by flume tank was possible in the weaker current speed than the similar lead sinker. In the coastal fishing grounds of Gangwon province, the comparison of catching efficiency was made between the improved fishing gears composed of the environment-friendly sinkers and artificial baits, and the current used fishing gears of lead sinkers and pig-fat baits. The result showed the tendency in which the improved fishing gears caught the bigger octopuses than the current used fishing gears. In the quantity and number of the fish catch per unit fishing gear, the improved fishing gear showed a little more catch than the current used fishing gear, regardless of the fishing area. However, the number of the improved fishing gears lost during fishing operation was similar to that of the current used fishing gears.

• 한국해양공학회지
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• 제25권1호
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• pp.49-55
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• 2011

The EG/AD/S model ice, originally developed by Timco (1986), was selected as the primary model ice material for the newly built MOERI Ice Model Basin in Korea. However, the existence of a sugar component in the EG/AD/S mixture may cause a serious maintenance problem, as described in certain references. This study focuses on the tests of the mechanical properties of the EG/AD/S and the EG/AD model ice. In order to understand the influence of sugar in the original EG/AD/S model ice and to find a possible substitute for sugar, a series of tests with the EG/AD model ice were performed, and the results were compared to those of the EG/AD/S model ice. The relatively large size of the MOERI Ice Model Basin made it difficult to control the initial strength of model ice, so it took a much longer time to achieve the target strength. In order to obtain a lower strength and stiffness for the model ice, the amount of chemical additives may be varied to achieve the desired strength level. This paper is a preliminary study aimed at seeking a possible substitute for the original EG/AD/S model ice for utilization in a large-scale ice tank. To understand the influence of sugar in the original EG/AD/S model ice, the mechanical properties of the EG/AD/S and EG/AD model ice, such as flexural strength, compressive strength, and elastic modulus, were tested in the laboratory condition and compared to each other. The warm-up procedure seems to be an important factor to reduce ice strength in the tests, so it is discussed in detail.

• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1494-1500
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• 2012

Fermentation with filamentous fungi in a bioreactor is a complex dynamic process that is affected by flow conditions and the evolution of the rheological properties of the medium. These properties are mainly affected by the biomass concentration and the morphology of the fungus. In this work, the rheological properties of a fermentation with the fungus Beauveria bassiana under different hydrodynamic conditions were studied and the rheological behavior of this broth was simulated through a mixture of carboxymethyl cellulose sodium and cellulose fibers (CMCNa-SF). The bioreactor was a 10 L CSTR tank operated at different stir velocities. Rheological results were similar at 100 and 300 rpm for both systems. However, there was a significant increase in the viscosity accompanied by a change in the consistence index, calculated according to the power law model, for both systems at 800 rpm. The systems exhibited shear-thinning behavior at all stir velocities, which was determined with the power law model. The mixing time was observed to increase as the cellulose content in the system increased and, consequently, the efficiency of mixing diminished. These results are thought to be due to the rheological and morphological similarities of the two fungal systems. These results will help in the optimization of scale-up production of these fungi.

• 대한기계학회논문집B
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• 제25권2호
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• pp.180-186
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• 2001

The condensation heat transfer coefficients of pure refrigerants R-22, R-134a, and a binary refrigerant mixture R-410A flowing in a small diameter tube were investigated. The experiment apparatus consists of a refrigerant loop and a water loop. The main components of the refrigerant loop consist of a variable-speed pump, a mass flowmeter, an evaporator, and a condenser(test section). The water loop consists of a variable-speed pump, an isothermal tank, and a flowmeter. The condenser is a counterflow heat exchanger with refrigerant flowing in the inner tube and water flowing in the annulus. The test section consists of smooth, horizontal copper tube of 3.38mm outer diameter and 1.77mm inner diameter. The length of test section is 1220mm. The refrigerant mass fluxes varied from 450 to 1050kg/(㎡$.$s) and the average inlet and outlet qualities were 0.05 and 0.95, respectively. The main results were summarized as follows ; in the case of single-phase flow, the heat transfer coefficients increase with increasing mass flux. The heat transfer coefficient of R-410A was higher than that of R-22 and R-134a, and the heat transfer for small diameter tubes were about 20% to 27% higher than those predicted by Gnielinski. In the case of two-phase flow, the heat transfer coefficients also increase with increasing mass flux and quality. The condensation heat transfer coefficient of R-410A was slightly higher than that of R-22 and R-134a. Most of correlations proposed in the large diameter tube showed significant deviations with experimental data except for the ranges of low quality and low mass flux.

• 한국잡초학회지
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• 제18권3호
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• pp.246-256
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• 1998

Metsulfuron-methyl 처리시 옥수수에 발현되는 자색화의 원인을 알아보기 위하여 제반실험을 수행하였다. Metsulfuron-methyl 처리시 농도와 시간에 의존하여 당과 anthocyanin의 함량이 증가되었고, 증가된 anthocyanin은 ILE+VAL이나 DCMU 처리에 의해서 경감되었다. 당을 외부로부터 공급하였을 때 당 농도에 의존하여 anthocyanin 함량이 증가되었고, 당형성이 제한되어 있는 백화조직에서는 metsulfuron-methyl 처리로 anthocyanin 생성이 증가되지 않았다. 그리고 metsulfuron-methyl은 광합성 자체를 억제하지 않았다. Metsulfuron-methyl에 의한 anthocyanin 축적을 구조 유전자 변이주 모두에서는 관찰할 수 없었고, 조절유전자 변이주 중에서는 R-r, r-r에서만 anthocyanin축적을 관찰할 수 있었다. 이들의 제반 결과는 metsulfuron-methyl이 처리되면 광합성 산물인 당이 축적되고, 이는 anthocyanin 생합성 과정에 관련된 유전자를 자극함으로써 anthocyanin 생합성과정을 활성화시키며 이로 인해 옥수수가 자색화됨을 시사해 준다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권1호
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• pp.72-79
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• 2006

Kojic acid production by Aspergillus flavus strain S44-1 using sucrose as a carbon source was carried out in a 250-mL shake flask and a 2-L stirred tank fermenter. For comparison, production of kojic acid using glucose, fructose and its mixture was also carried out. Kojic acid production in shake flask fermentation was 25.8 g/L using glucose as the sole carbon source, 23.6 g/L with sucrose, and 6.4 g/L from fructose. Reduced kojic acid production (13.5 g/L) was observed when a combination of glucose and fructose was used as a carbon source. The highest production of kojic acid (40.2 g/L) was obtained from 150 g/L sucrose in a 2 L fermenter, while the lowest kojic acid production (10.3 g/L) was seen in fermentation using fructose as the sole carbon source. The experimental data from batch fermentation and resuspended cell system was analysed in order to form the basis for a kinetic model of the process. An unstructured model based on logistic and Luedeking-Piret equations was found suitable to describe the growth, substrate consumption, and efficiency of kojic acid production by A. flavus in batch fermentation using sucrose. From this model, it was found that kojic acid production by A. flavus was not a growth-associated process. Fermentation without pH control (from an initial culture pH of 3.0) showed higher kojic acid production than single-phase pH-controlled fermentation (pH 2.5, 2.75, and 3.0).

• 한국잡초학회지
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• 제6권2호
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• pp.124-129
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• 1986

보리밭의 잡초방제(雜草防除)를 위하여 몇 가지 겨엽처리형제초제(莖葉處理型除草劑)를 공시(供試)하여 시험(試驗)한 결과(結果)를 보면 1. 공시약제중(供試藥劑中) 살초력(殺草力)은 Bromoxynil + MCPA와 Bromoxynil이 Ioxynil 보다는 효과적(效果的)이었다. 2. 이들 약제(藥劑)들의 시용량(제품)(施用量(製品))은 100g/10a 보다는 200g/10a 시용량(試用量)에서 살초효과(殺草效果)가 높았다. 3. 약제(藥劑)의 살포시기(撒布時期)는 이들 3엽제(葉劑) 모두 3월(月)보다는 4월(月) 초순(初旬)에 살포(撒布)되는 하잡초(夏雜草)도 방제(防除)할 수 있었기 때문이었다. 4. 보리 파종직후(播種直後) 토양처리제(土壤處理劑)로서 Butachlor를 처리(處理)하고 4월(月) 초(草)에 경엽처리제(莖葉處理劑)로서 Bromoxynil 이나 Bromonynil + MCPA를 처리(處理)한 구(區)에는 거의 완전방제(完全防除)가 가능(可能)하였다. 5. Bromoxynil+MCPA 약제(藥劑)로 30여(餘) 초종(草種)들의 살초력(殺草力)을 본 결과(結果) 주(主)로 광엽잡초(廣葉雜草)에 효과(效果)가 있어 답이작(畓裏作)보다는 전작맥류포(田作麥類圃)에 발생(發生)되는 잡초(雜草)를 대상(對象)으로 방제(防除)하는 것이 좋을 것으로 본다. 6. 잡초발생량(雜草發生量)(잡초건물중(雜草乾物重))과 보리 수량(收量)과의 회귀식(回歸式)은 y=593.112-0.41x(r=$-0.918^{**}$)로서 고도(高度)의 역상관(逆相關)을 보였다.

• 한국작물학회지
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• 제26권2호
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• pp.179-184
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• 1981

본 시험은 1980년도에 전남대학교 시험포장에서 수행된 것으로서, Metribuzin의 처리시기에 따른 품종반응차이를 알기 위하여 광교외의 5대두품종과 Pre-sowing 외에 4처리 시기를 공시하여 작물의 초기생육반응을 조사하여 다음의 결과를 얻었다. 1. 공시품종내에서는 약제에 대한 저항성 차이가 뚜렷하지 않았다. 2. 품종차이보다는 약제처리시기에 따른 반응차이가 헌저하였으며, 대부분 대두품종의 저항성 크기는 E. Post-emg.< L.Post-emg $\ll$re-sowing=Control의 순으로 컸다. 3. Metribuzin의 약해 Symptom은 주당엽수 < 초장 $\ll$주당분지수의 순으로 뚜렷한 감소를 보이는 특징이었다. 4. 우리나라 대두품종에 대한 Metribuzin의 사용은 Pre-sowing이나 Pre-emg.가 추천되며, 특히 Pre-sowing에 대한 토양혼화법 연구와 단제보다는 혼용처리의 이점을 찾을 필요가 있다.

• 공업화학
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• 제22권3호
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• pp.332-335
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• 2011

친환경 재료에 대한 관심이 급증함에 따라 재료의 구조적 기능성 및 투수성을 동시에 갖는 다공성 콘크리트의 활용이 증가되고 있다. 본 연구에서는 다공성 콘크리트에 제올라이트를 혼합하여 다양한 활용도를 갖는 다기능형 옥석 제품의 수질정화 능력을 평가하여 친환경제품으로서의 적합성을 검토하였다. 흐름이 없는 시험용 수조에서 시간에 따른 오염도 제거율은 T-N (70.6%), T-P (67.0%), BOD (57.7%), TOC (50.6%) 순으로 우수한 수질정화 특성을 보였다. 또한 유입 및 유출이 가능한 비점오염원에서 시간에 따른 유출부에서의 수질오염도 및 중금속 농도의 제거율은 Zn (99.9%), Pb (90.0%), BOD (69.2%), COD (33.5%) 순으로 흐름이 없는 경우에서의 오염도 제거율보다 수질정화 특성이 우수한 것으로 나타났다. 따라서 다공성 콘크리트 시설물을 실제 하천 등에 시공했을 시에 우수한 오염도 제거율을 바탕으로 친환경제품으로 적합함을 확인할 수 있었다.

• 한국잡초학회지
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• 제5권1호
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• pp.73-84
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• 1985

남부지방(南部地方) 만파대두포장(晩播大豆圃場)의 잡초방제(雜草防除)를 위한 Aciflurofen과 Haloxyfop-methyl의 조합처리반응(組合處理反應)을 조사(調査) 분석(分析)한 결과(結果), 다음의 몇가지 결론(結論)을 얻었다. 1. 화본과잡초(禾本科雜草)가 선우점(先優占)했던 만파대두포장(晩播大豆圃場)에서 9월(月)에 가장 많은 잡초종(雜草種)(25종(種))이 출현(出現)하고 있었으며, 광엽(廣葉) 및 사초과잡초(莎草科雜草)의 발생(發生)을 화본과잡초(禾本科雜草)의 방제정도(防除程度)에 비례(比例)하여 천이적(遷移的)으로 이루어지고 있었다. 2. Haloxyfop-methyl의 단독처리(單獨處理)에서는 9월중(月中)의 광엽(廣葉) 및 사초과잡초(莎草科雜草)에 대한 방제수단(防除手段)이, Acifluorfen의 단독처리(單獨處理)에서는 8 9월의 화본과잡초(禾本科雜草)에 대한 방제수단(防除手段) 보완(補完)이 요구(要求)되었다. 3. 9 10월(月)까지의 지속적(持續的)인 제초(除草)를 위하여 Haloxyfop-methyl은 0.3~0.4kg, Acifluorfen은 0.3~0.5kg ai/ha의 조합처리(組合處理)가 요구되었다. 4. 조합처리시(組合處理時)의 Haloxyfop-methyl의 작용력(作用力)은 약량(藥量)에 관계(關係)없이 0.25~0.4kg ai/ha까지 양성반응(陽性反應)이었으나 Acifluorfen의 작용력(作用力)은 7 8월(月)에 대체로 음성반응(陰性反應)을 보였고 이후에 서서히 양성반응(陽性反應)으로 전환(轉換)하였으며, 양성적(陽性的)인 상호작용반응(相互作用反應)이 실용적(實用的) 조합수준(組合水準)에서 인정(認定)되었다. 5. Colby의 상대협력계수(相對協力係數) 분석결과(分析結果)로는 두 약제조합처리(藥劑組合處理)로 각(各) 초종군(草種群)에 대한 결과(結果)는 길항적(拮抗的)인 것으로나 전체초종(全體草種)에 대한 방제효과(防除效果)는 협력적(協力的)인 것으로 해석(解析)이 되었다. 6. 대두(大豆)의 협수(莢數) 7 8월(月), 종실수량(種實收量)은 9월(月), 경건중(莖乾重)은 10월(月)의 제초효과(除草效果)와 관계(關係)가 깊은 것으로 해석(解析)되었고, 유사한 결과를 곡선회귀분석(曲線回歸分析) 결과(結果)로도 인정(認定)할 수 있었다. 7. 본(本) 연구(硏究)와 유사(類似)한 조건하(條件下)에서는 Haloxyfopmethyl과 Acifluorfen을 각각 0.4kg/ha 정도(程度)의 수준(水準)에서 조합처리(組合處理)됨이 타당(妥當)할 것으로 판단(判斷)되었다.