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        검색결과 242

        121.
        2011.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Experimental fishing was carried out to compare the catches of main species and bycatch according to the codend mesh size (raschel, 15mm, 25mm, 35mm, 45mm) of stow net on anchor in the coastal waters of Seocheon after manufacturing five kinds of fishing gears and commercial fishing boat (7.93 tons) was used for it. Anchovy (Engraulis japonicus), southern rough shrimp (Trachysalambria curvirostris), beka squid (Loligo beka), cuttle fish (Sepia esculenta), swimming crab (Portunus trituberculatus) were dominant on the five kinds of experimental fishing gears. Southern rough shrimp was caught from all kinds of fishing gears and catches of anchovy was highest in the raschel codend, southern rough shrimp for 15mm, 25mm, 35mm codend and beka squid for 45mm codend. Bycatch proportion against total catches was 623,376g (28.7%) for 2,171,844g in raschel, 11,932g (1.7%) for 704,451g in 15mm, 3,616g (1.6%) for 221,432g in 25mm, 9,276g (4.9%) for 191,052g in 35mm and 2,724g (5.3%) for 51,431g in 45mm.
        4,200원
        122.
        2011.04 구독 인증기관 무료, 개인회원 유료
        The conventional RC flat plate slab system have many good features, which are design flexibilities, saving of story-height and economy of construction etc. But the study of flat plate slab system for H-steel or SRC column have been rare both at home and abroad. Main topics in this study is a new structural detail for connection between H-Steel or SRC column and flat plate slab. The test for lateral performance of connection between H-Steel or SRC column and flat plate slab was carried out. From the test results structural characteristics - yield moment, yield rotation, maximum moment, deformation capabilities and so on - are obtained and evaluated.
        3,000원
        123.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The transesterification of rapeseed oil, soybean oil, and mixed fat were conducted at 65℃ with Al2O3-supported CaO, 0.8 wt% KOH, 1 wt% NaOH and mixed catalyst. The overall conversion(%) of rapeseed oil indicated to be 96% at the 12:1 molar ratio of methanol to oil, 8 wt% CaO and 2 wt% water. The pH ranges of biodiesel for mixed fat using four catalysts and for three fats using 8wt% CaO were 7.3-9.1, 7.3-7.5, respectively. The volumes of water needed to wash biodiesel from rapeseed oil using 0.8 wt% KOH and 8 wt% CaO were 15 mL and 3 mL.
        4,000원
        124.
        2010.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A diamond-like carbon (DLC) film deposited on a WC disk was investigated to improve disk wear resistance for injection molding of zirconia optical ferrule. The deposition of DLC films was performed using the filtered vacuum arc ion plating (FV-AIP) system with a graphite target. The coating processing was controlled with different deposition times and the other conditions for coating, such as input power, working pressure, substrate temperature, gas flow, and bias voltage, were fixed. The coating layers of DLC were characterized using FE-SEM, AFM, and Raman spectrometry; the mechanical properties were investigated with a scratch tester and a nano-indenter. The friction coefficient of the DLC coated on the WC was obtained using a pin-on-disk, according to the ASTM G163-99. The thickness of DLC films coated for 20 min. and 60 min. was about 750 nm and 300 nm, respectively. The surface roughness of DLC films coated for 60 min. was 5.9 nm. The Raman spectrum revealed that the G peak of DLC film was composed of sp3 amorphous carbon bonds. The critical load (Lc) of DLC film obtained with the scratch tester was 14.6 N. The hardness and elastic modulus of DLC measured with the nano-indenter were 36.9 GPa and 585.5 GPa, respectively. The friction coefficient of DLC coated on WC decreased from 0.2 to 0.01. The wear property of DLC coated on WC was enhanced by a factor of 20.
        4,000원
        125.
        2010.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To estimate the mesh selectivity of monofilament and multifilament gill net for Marbled sole, Pleuronectes yokohamae, the field testes were carried out 12 times with five different mesh sizes (86.6, 101.0, 121.2, 137.7, 151.5mm) in the western sea of Korea, 2007-2009. The master curve of selectivity was estimated by the extended Kitahara's method. In the field testes, the total number of species and catch were 26 and 987, respectively. The catch number of marbled sole was 728 and occupied 73.8% in total catch. The optimum values of l/m for 1.0 of retention probability in monofilament and multifilament gill net were estimated 0.288 and 0.307, respectively and l/m was estimated to be 0.189, 0.203, 0.213, 0.222 and 0.230 in case of monofilament gill net and 0.171, 0.191, 0.205, 0.216 and 0.227 in case of multifilament gill net when the retention probability were 0.1, 0.2, 0.3, 0.4 and 0.5, respectively. The 0.5 selection range of multifilament gill net was wider about 1.5 times than that of monofilament gill net according as multifilament gill net was 0.216 and monofilament gill net was 0.148. So the multifilament gill net has a low selectivity than that of the monofilament gill net. To estimate the optimum mesh size on first maturity length 19.5cm of marbled sole, the retention probability value of 0.1 was adopted in consideration of using the gill net for marbled sole at present. The optimum mesh size were estimated to be 103.2mm and 114.0mm in monofilament gill net and multifilament gill net, respectively, on first maturity length 19.5cm of marbled sole.
        4,200원
        126.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The continuous transesterification of mixed fat was done on the plug flow reactor packed with the static mixers. The transesterification using 0.5 wt% KOH, 0.8 wt% TMAH and mixed catalyst[40 v/v% KOH(0.5 wt%)+60 v/v% TMAH(0.8 wt%)] was conducted with the changes of molar ratios, weight percentage of beef, flow rates and number of static mixer's elements at 65℃. The overall conversion of mixed fat at 1:8 molar ratio, 50 wt% of beef and 24 of static mixer's elements increased until 0.7mL/min of flow rate. The overall conversion of mixed fat showed 96% at those conditions. So, the optimum operating conditions on tublar reactor were 1:8 molar ratio, 50 wt% of beef, 0.7 mL/min of flow rate and 24 of static mixer' s elements.
        4,000원
        127.
        2010.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZnO nanostructures were grown on an Au seed layer by a hydrothermal method. The Au seed layer was deposited by ion sputter on a Si (100) substrate, and then the ZnO nanostructures were grown with different precursor concentrations ranging from 0.01 M to 0.3M at 150˚C and different growth temperatures ranging from 100˚C to 250˚C with 0.3 M of precursor concentration. FE-SEM (field-emission scanning electron microscopy), XRD (X-ray diffraction), and PL (photoluminescence) were carried out to investigate the structural and optical properties of the ZnO nanostructures. The different morphologies are shown with different growth conditions by FE-SEM images. The density of the ZnO nanostructures changed significantly as the growth conditions changed. The density increased as the precursor concentration increased. The ZnO nanostructures are barely grown at 100˚C and the ZnO nanostructure grown at 150˚C has the highest density. The XRD pattern shows the ZnO (100), ZnO (002), ZnO (101) peaks, which indicated the ZnO structure has a wurtzite structure. The higher intensity and lower FWHM (full width at half maximum) of the ZnO peaks were observed at a growth temperature of 150˚C, which indicated higher crystal quality. A near band edge emission (NBE) and a deep level emission (DLE) were observed at the PL spectra and the intensity of the DLE increased as the density of the ZnO nanostructures increased.
        4,000원
        128.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Retarding retrogradation of Korean rice cakes(Karedduk) with a mixture of trehalose and Sun-Tender added, after 0, 24, and 48 hr of storage at 5℃, was analyzed by Avrami kinetics. A central composite design was used for arrangement of treatment. The two independent variables selected for retarding retrogradation analysis were amounts of trehalose(x) and Sun-Tender(y). Trehalose was added at 0, 3, 6, 9, and 12% levels, and Sun-Tender added at 0, 0.3, 0.6, 0.9, and 1.2% levels, to dry rice flour. The Avrami exponent(n) for the mixtures of 9% trehalose and 0.3% Sun-Tender, and 9% trehalose and 0.9% Sun-Tender were lower than in the control. The time constant(1/k) for the mixture of trehalose and Sun-Tender was higher than in the control. The effect of retarding retrogradation of Korean rice cakes with added mixtures of trehalose and Sun-Tender showed an increasing trend as the amount of trehalose increased. These results suggest that adding a mixture of 9% trehalose and 0.3% Sun-Tender, or 9% trehalose and 0.9% Sun-Tender to Korean rice cakes(Karedduk) is effective for retarding retrogradation.
        4,000원
        129.
        2010.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Experimental fishing was carried out to compare fishing status according to the codend mesh size (raschel, 15mm, 25mm, 35mm, 45mm) of stow net on anchor in the coastal waters of Seocheon after manufacturing five kinds of fishing gears and commercial fishing boat (7.93 tons) was used for it. Total catches of raschel, 15mm, 25mm, 35mm, 45mm codend were 816,949g, 203,994g, 1,405g, 51,576g, 194g in September and 40,545g, 66,974g, 14,692g, 12,647g, 12,655g in October. Dominance species were anchovy (Engraulis japonicus) in raschel codend, largehead hairtail (Trichiurus lepturus) in 15mm and 35mm in September, and the amount of catches was very small in 25mm and 45mm codend due to the fishing gear damage. In October, dominance species were anchovy and beka squid (Loligo beka) in raschel, 15mm, 25mm codend, and cuttlefish (Sepia esculenta) and beka squid were mainly caught in 35mm and 45mm codend. In addition, total length of anchovy and cardinal fish (Apogon lineatus) were increased according to the increase of codend mesh size but there was no difference in the mantle length of cuttlefish and loligo beka.
        4,000원
        130.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The esterification of palmitic acid in Jatropha Oil using 8wt% p-TSA catalyst was done at the 1:8 molar ratio of oil to methanol and 65℃. The conversion of palmitic acid appeared to be 95.3% in 60min. After that, the continuous transesterification of the oil using 0.5wt% KOH, 0.8wt% TMAH mixed catalyst[40vol% KOH(0.5wt%) + 60vol% TMAH(0.8wt%)] and 1.1wt% TMAH was conducted with the flow rates and the molar ratios at 65℃. The overall conversion of Jatropha Oil increased with the decrease of flow rate and showed 95.6% with 9ml/min of flow rate at the 1:8 molar ratio of oil to methanol and 65℃. But it showed 87% with 15ml/min of flow rate at the same conditions. The recovery of methanol(%) appeared to be 86% at the 1:8 molar ratio of oil to methanol, mixed catalyst and 65℃.
        4,000원
        134.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        135.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The esterification of the reactants of Jatropha oil and methanol added by propyleneglycol was done using p-TSA catalyst. And then the emulsification of triglyceride and methanol was conduced by 1.0vol% GMS. The emulsified reactants were transesterified at 65℃ using TMAH and mixed catalyst (50wt%-TMAH+50wt%-NaOH) respectively. The esterification conversion at the 1:8 molar ratio of free fatty acid to methanol using 8.0wt% p-TSA was 94.7% within 80min. The overall conversion at the 1:8 molar ratio of mixed fat(50wt% Beef Tallow) to methanol and 65℃ using mixed catalyst was 95.4% The cloud point of Biodiesel decreased with the addition of petroleum diesel.
        4,000원
        136.
        2009.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A series of fishing experiments was carried out in the eastern coastal waters of Korea from January, 2002 to March, 2003, using gill nets of different mesh sizes (m 180, 210, 240, 270 and 300 mm) to determine the size selectivity of gill net for female snow crab, Chionoecetes opilio. The catch of experimental gears was mostly snow crab (97%), Chionoecetes opilio. The maximum carapace length (RL) of each female snow crab caught in the fishing experiments was measured. The master selection curve was estimated by applying the extended Kitahara s method. The selection curve showed that the gill nets of larger mesh size allowed more female crabs of small carapace size to escape. The optimum values of RL/m for 1.0 of retention probability was 0.563 and RL/m was estimated to be 0.249, 0.290, 0.319, 0.344 and 0.367 when the retention probability were 0.1, 0.2, 0.3, 0.4 and 0.5, respectively.
        4,000원
        137.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        부탄올을 투과증발 공정으로 분리하기 위하여 복합공정에 의하여 투과증발막을 제조하였다. 상업용 poly(dime-thylsiloxane) (PDMS) 막을 plasma 처리시키거나, polysulfone, poly(ether imide) 막을 지지체로 사용하여 plasma 처리 및 PDMS 코팅의 복합공정을 적용하였다. 헥산계열과 실란계열 유기 화합물을 사용하여 PDMS막을 plasma 처리하였을 경우 막 표면의 소수성을 증가시켜서 부탄을 선택도가 12.56까지 향상되었다. 반면에 투과량은 막 표면의 소수성 증대와 free volume의 변화로 인해 1.15 kg/m 2 ⋅hr까지 감소되어 선택도와 반대의 성향을 나타내었다. 막의 소수성이 증가함에 따라 접촉각과 상대적 sorption 비가 증가하였고, 부탄을 선택도도 향상되었다. PDMS 코팅 용액에서 prepolymer의 함량이 높을수록 부탄올 선택도가 증가하였다. PDMS 코팅과 plasma 처리 공정의 순서에 따른 영향을 조사하였다. 부탄올과 노르말 헥산으로 plasma 처리할 경우 plasma처리, PDMS 코팅 순으로 제조된 막의 분리 성능이 우수하였고 hexamethyldisilane과 hex-amethyldisilazane을 사용한 경우에는 역순으로 제조된 막의 분리 성능이 더 우수한 것으로 나타났다.
        4,000원
        138.
        2009.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한국은 매년 봄철 중국의 서부지역 및 몽골로부터 불어오는 황사 피해를 받고 있다. 황사발생은 현재 한국을 비롯하여 일본, 멀리 아메리카 대륙에 이르기까지 환경문제를 일으키고 있다. 중국의 서부지역은 장기간의 기후변화와 인간의 훼손행위로 인해 사막화가 급격히 가속되고 있는 실정이다. 이에 중국을 비롯한 각국은 식물식재를 통한 사막의 생태적인 복원을 모색하고 있다. 따라서 본 연구는 사막의 생태적인 식생복원을 위한 기초자료를 얻기 위해 중국 서북부의 대표적인 건조지인 빠이청(白城)지역의 식생을 조사하였다. 건조지에 1차적으로 침입한 강아지풀은 건조에 따른 토양의 염분농도 상승과 알칼리화와 더불어 Artemisia mongolica-강아지풀군락을 비롯하여 강아지풀-Cannabis sativa var. fruderalis 군락으로 천이하였다. 환경조건의 지속적인 악화와 더불어 강한 바람에 의한 증발량 상승으로 건조가 극심한 평지에서는 최종적으로 Artemisia mongolica 군락이 일부 잔존하였다. 시간변화에 따라 간헐적인 그늘이 생길 수 있는 구릉지는 상대적으로 공중습도가 확보될 수 있어 다른 유형의 식생이 나타났다. 조사대상지의 전 지역에 흔히 분포하는 남가새군락은 토양환경 악화와 더불어 남가새-Cleisrogenes squarrosa 군락으로 천이하였고 낮은 구릉지 지형조건에서 환경악화와 더불어 건조와 토양염분 및 강알칼 토양에 강한 Cleisrogenes squarrosa 군락이 최종적으로 형성되었다. 또한 본 조사지 일대에서 건조에 강한 27과 49속 58종 4변종의 총 62분류군의 고등식물이 나타났다. 이 가운데 환경내성이 뛰어난 국화과식물이 27.4%로 가장 많이 조사되었다.
        4,000원
        139.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A cell is the product of a long period of evolution and can be represented as an optimized system (homeostasis). Stimuli from the outside environment are received by sensory apparatus on the surface of the cell and transferred through complicated pathways
        4,000원
        140.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원