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        검색결과 384

        81.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        계면중합법은 혼합되지 않은 두 용액에 용해되어 있는 반응성 단량체들이 계면에서 중합되는 기술로 다양한 분야 에 응용되고 있다. 이 중, 수처리 분리막의 경우 m-phenylene diamine과 Trimesoyl chloride를 반응물로 사용하고 있다. 분리 막의 성능은 다양한 중합 성능에 의해 영향을 받고 있으며, 본 연구에서는 유기 용액의 퍼짐 속도가 어떻게 분리막 표면 및 구조에 영향을 주는지를 주사전자현미경을 통해 고찰하였다. 퍼짐 속도는 7.6과 25 mm/sec로 조절하였으며, 유기상 용액은 1~3방울까지 조절하였다. 관찰된 결과는 퍼짐 속도가 7.6 mm/sec에서는 한 방울 떨어트릴 경우, 25 mm/sec에서는 두 방울 떨어트릴 경우 폴리아마이드 막에 균열을 발견할 수 없었다. 반면 나머지 경우에 모두 균열이 발생하였다. 따라서, 초기 유기 용액의 퍼짐 속도는 폴리아마이드 분리막의 성능에 영향을 줄 것으로 관찰되었다.
        4,000원
        82.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        인위적인 온실 가스 배출로 인한 자연 재해가 증가하고 있으며 이로 인해 기체 분리막의 개발이 촉진되게 되었다. 이산화탄소(CO2)는 지구 온난화의 주요 원인이다. 고유의 유연성을 가지는 유기 고분자 막은 기체 분리막의 좋은 후보군 중 하나이며, 이 중 이산화탄소에 대한 높은 확산도를 가지고 있는 폴리디메틸실록산(PDMS)은 유망한 소재이다. 또한, 폴리비 닐피롤리돈(PVP)은 이산화탄소에 대한 높은 용해도를 가지고 있는 고분자로 기체 분리막에 활용될 수 있다. 따라서 본 연구 에서는 용이한 조건에서 간단한 단일 반응 자유 라디칼 중합에 의하여 다양한 조성의 폴리디메틸실록산-폴리비닐피롤리돈 (PDMS-PVP) 빗살 공중합체를 합성하였다. PDMS와 PVP로 합성된 공중합체는 FTIR을 통해 분석하였다. 고분자의 형태학 및 열적 특성은 TEM, TGA 및 DSC를 통하여 분석하였다. PDMS-PVP 빗살 공중합체를 다공성 폴리설폰 지지체 위에 코팅 하여 복합막을 제조했으며, 제조한 복합막의 기체 투과 특성을 분석하였다. 그 결과 이산화탄소의 투과도 및 이산화탄소/질소 선택도가 각각 140.6 GPU 및 12.0에 도달하였다.
        4,000원
        83.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the morphology and antioxidant content of shiitake mushrooms (Lentinula edodes) cultivated in smart farms and general farms have been compared. With regard to morphology, mushrooms produced in the smart farm system exhibited a slightly thicker and wider pileus and thicker and longer stipe than those in the general farm system. The stipe in the mushrooms from moderate-sized farms was harder, because the low relative humidity of cultivation rooms could induce mushroom tissue to harden. With regard to the antioxidant content, the free radical scavenging activity was evaluated by the DPPH assay. Among the various treatments, hot water extracts of freeze-dried shiitake produced from smart farms exhibited the highest DPPH value of 37.8%. In contrast, the lowest activity of 12.2% was observed in a 70% fermented alcohol extract of shiitake that was dried by hot air. The polyphenol content was higher in hot water extracts than in 70% fermented alcohol extracts. Additionally, the polyphenol content was higher in the freeze-dried samples than in hot-air dried ones. The smart-farm system was preferred over the general cropping system for cultivating shiitake mushrooms, because the antioxidant activity and polyphenol content of mushrooms from the smart-farm system was better; the functionality of this system was more improved than that of the general cropping system, and it enables mushrooms to be cultivated more efficiently. The antioxidant content is represented as the mean±SD of three replicates. Different letters indicate significant differences among samples, i.e., p<0.05.
        3,000원
        84.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        동아시아 지역 신석기시대 다원커우 (大汶口)문화의 대표적 유물인 삼 족기는 다른 문화권에서는 볼 수 없는 ‘새 모양의 몸체에 세 개의 다리’ 가 달려 있는 독특한 형태의 그릇이다. 본 논문은 이 특별한 삼족기의 형 태에 대하여 그 근원을 고찰 한 것이다. 중국의 미학자 리쩌허우는 그의 저서 『미의 역정』에서 이 삼족기가 세 개의 다리를 가진 것에서 ‘자연계를 모방하지 않은 인류 최초의 형식 창 조’라고 한 바 있다. 그러나 본 논문은 이 삼족기가 새의 모양인 것에 주 목하여 새 혹은 그와 비슷한 대상을 모방했을 가능성과 그 창조의 근원 이 될 수 있는 고대인들의 특별한 관념에 대하여 고찰 하였다. 삼족기의 특징인 세 개의 다리 형식은 북방의 몽골 유목민에서 전래되 어 동북 지역의 훙산 (紅山)문화에서 체계화된 숫자 3에 대한 특별한 관 념에서 비롯된 것으로 보인다. 삼족기는 이 관념이 인근 지역으로 확산 되면서 광범위한 지역에서 시대를 이어가며 제작 되었던 그릇의 한 형식 으로 다원커우 삼족기만의 특징이라 할 수는 없다. 그러나 새 모양의 형태는 다원커우 삼족기만의 특징으로 다원커우문 화의 초기부터 가지고 있었던 새토템의 영향으로 추정된다. 다원커우문 화는 동이족이 이룩한 문화로 고대의 저서 『한시외전 (韓詩外傳)』·『좌 전 (左傳)』·『회남자 (淮南子)』·『산해경』 등에 의하면 초기의 태호족 시기부터 새토템을 가지고 있었으며, 중기의 소호족 시기에 태양 숭배 사상이 더해져서 태양새토템으로 발전하였고, 여기에 숫자 3에 대한 특 별한 관념이 더해져서 세 발 달린 까마귀인 삼족오를 숭배하는 삼족오 신앙을 가졌던 것을 알 수 있다. 관념으로서의 삼족오신앙이 형상으로 표현됨으로써 처음에는 <팽이형토기>에 태양을 실어 나르는 새를 상징 하는 평면적인 도상으로 나타났으며, 이후 입체적인 형태의 <태양신조형 (太陽神鳥型)토기>로 표현되었고, 마침내 삼족오를 닮은 새 모양의 몸 체에 세 개의 다리가 달린 제사용 도기 규 (鬹)가 제작되었는데 이것이 바로 다원커우문화의 삼족기라 할 수 있다. 그러므로 다원커우문화의 새 모양 삼족기는 리쩌허우가 말한 ‘자연계 를 모방하지 않은 인류 최초의 형식 창조’라기 보다는 다원커우인들의 관념 속에 숭배의 대상으로 존재했던 ‘삼족오를 형상화한 관념 대상의 모방’으로 보는 것이 타당할 것이다. 또한 중국의 중원에서는 수·당나라 이후로 이미 사라진 삼족오 도상 이 우리나라에서는 삼국시대에 볏이 뚜렷한 세 발 달린 봉황의 모습으로 더욱 화려하게 발전하여 우월한 민족성을 나타내는 표상으로 널리 사용 되었고 솟대 등의 상징물로 현대까지 계속 사용되고 있는 것은 다원커우 와 우리나라가 하나의 동이족 문화권임을 유추할 수 있다.
        5,800원
        85.
        2017.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        SiAlON-based ceramics are some of the most typical ceramic materials used as cutting tools for HRSA(Heat Resistant Super-Alloys). SiAlON can be fabricated using ceramic processing, such as mixing, granulation, compaction, and sintering. Spray drying is a widely-used method for producing a granular powder of controlled morphology and size with flowability. In this study, we report a systematic investigation aimed at optimizing spherical granule morphology by controlling spray-drying parameters such as gas flow and feed rate. Before spray drying, the viscosities of the raw material slurries were also optimized with the amount of dispersant added.
        4,000원
        86.
        2017.11 구독 인증기관·개인회원 무료
        Ionic liquid (IL), asymmetric chemical consist of bulky cations and tiny-mobile anions, has been known as promising DNA extraction, separation and preservation agent due to its strong interaction with DNA. However, the interaction underlying DNA-IL complex forming mechanism remains to be elucidated. Herein, we employed three types of ILs (EMIM-Cl, BMIM-Cl, and OMIM-Cl) to investigate the changes of DNA morphology upon the alkyl chain length of ILs by using solid-state nanopore technology combining with atomic force microscopy (AFM). The results of AFM show the different forms of DNA, including aggregate, stretching, and bundling shapes in terms of EMIM-Cl, BMIM-Cl, and OMIM-Cl, respectively, assuming that the shape of DNA-IL complexes is responding to the alkyl chain length of ILs. In DNA translocation experiment. From the alteration of blockade current signals during the DNA pass through the nanopore, we estimate that the shapes of DNA are changed due to the treatment with BMIM-Cl, and OMIM-Cl, which not only increased the blockade current signals about 2-4 times in the case of OMIM, but also decrease the event showing translocation of DNA folding, implying that the alkyl chain affect to DNA stretching and bundling. The results indicate the length of hydrophobic alkyl group of IL plays an important role in determination of DNA morphology, providing their further application in nanopore technique for slowing DNA translocation speed toward discovering protein-DNA interaction or DNA sequencing.
        87.
        2017.11 구독 인증기관·개인회원 무료
        In a previous study, it was reported that enzymatic hydrolysis under pressurization could be a new method which could produce arginine dipeptide and free amino acid in anchovy hydrolysate as salty enhancer at optimal condition. Powder is more efficient than liquid in terms of transport and storage stability. For the purpose of producing spray dried powder of various salt contents was investigated the effect of different salt concentration of anchovy hydrolysate on spray dried powder properties. The anchovy hydrolysate of various salt contents(in the range of approximately 0.7- 19.8% w/w) prepared adding the fish sauce (Dae-Young fish market) at inlet drying air temperatures of 120°C and 140°C. The process yield and physicochemical properties such as moisture content, bulk density, hygroscopicity and the morphology (EDS, XPS, XRD) of the anchovy hydrolysate powder was measured. The glass transition temperatures (Tg) of the powders equilibrated under various water activities were determined using a differential scanning calorimeter (DSC). Different drying conditions and salt concentration could generate anchovy hydrolysate powders with different process yield, bulk density and moisture content. The spray-dried anchovy hydrolysate powder was confirmed by XRD to be a mixture of an amorphous substances and crystalline salts. The energy dispersive X-ray spectrometer (EDS) and X-Ray Photoelectron Spectroscopy (XPS) analysis demonstrated that the surface NaCl concentration of the powders increased with an increasing drying air temperature. Increasing moisture adsorption of the anchovy hydrolysate powders resulted in a Tg reduction. It is suggested that producing spray dried anchovy hydrolysate for the industrial use is the use of the feed salt concentration of not lower than % w/w and inlet air temperature at 120°C, 140°C
        88.
        2017.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, we investigated the overpotential of precipitation related to the catalytic activity of electrodes on the initial process of electrodeposition of Co and Co-Ni alloys on polycrystalline Cu substrates. In the case of Co electrodeposition, the surface morphology and the magnetic property change depending on the film thickness, and the relationship with the electrode potential fluctuation was shown. Initially, the deposition potential(−170 mV) of the Cu electrode as a substrate was shown, the electrode potential(Edep) at the Ton of electrodeposition and the deposition potential(−600 mV) of the surface of the electrodeposited Co film after Toff and when the pulse current was completed were shown. No significant change in the electrode potential value was observed when the pulse current was energized. However, in a range of number of pulses up to 5, there was a small fluctuation in the values of Edep and Eimm. In addition, in the Co-Ni alloy electrodeposition, the deposition potential(−280 mV) of the Cu electrode as the substrate exhibited the deposition potential(−615 mV) of the electrodeposited Co-Ni alloy after pulsed current application, the Edep of electrodeposition at the Ton of each pulse and the Eimm at the Toff varied greatly each time the pulse current was applied. From 20 % to less than 90% of the Co content of the thin film was continuously changed, and the value was constant at a pulse number of 100 or more. In any case, it was found that the shape of the substrate had a great influence.
        4,000원
        93.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 열유도 상분리법(thermally induced phase separation, TIPS)을 사용하여, 수처리 분리막에 적용하기 위 해, 응고조의 열용량의 변화를 위해 서로 다른 두 용액의 함량을 조절하였다. 또한, 온도의 변화를 통해 분리막의 구조 변화 에 대하여 관찰하였다. 분리막을 제조하기 위한 소재로는 수처리 분리막에 주로 이용되는 기계적 물성과 내화학성이 우수한 poly (vinylidene fluoride)(PVDF)를 사용하였고, 첨가제로 실리카를 이용하였다. 희석제는 PVDF와 호환성이 좋은 dioctyl phthalate (DOP), dibutyl phthalate (DBP)를 사용하였다. 응고액의 함량 변화에 따른 열용량 변화에 따라 제조된 분리막의 구 조를 관찰하기 위해 SEM 이미지를 촬영하였다. 열용량이 증가할수록 PVDF의 결정화 속도가 느려져 큰 기공을 나타내며 열 용량이 작을수록 결정화 속도가 증가하여 작은 기공이 생기는 것을 확인하였다.
        4,000원
        94.
        2017.10 구독 인증기관·개인회원 무료
        Morphology of antennal sensilla and their distribution were investigated in male and female adults of Plautia stali,a major pest of tree fruits, using scanning electron microscopy. Antennae of P. stali was composed of a scape, a pediceland three flagella in both sexes. Four types of sensilla (s. trichodea, s. basiconica, s. chaetica, s. coeloconica) were identifiedfrom both sexes. Among them, s. trichodea and s. basiconica were multiporous, others are not. They distributed in varyingnumbers. Sexual dimorphism was not shown in the distribution of the four sensilla types. But their distribution was characterizedalong antennal segments in both sexes. This study will be useful in electrophysiological and behavioral studies on theolfactory sensory function of each morphological type of sensilla.
        95.
        2017.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Surface morphology and optical properties such as transmittance and haze effect of glass etched by physical and chemical etching processes were investigated. The physical etching process was carried out by pen type sandblasting process with 15~20 μm dia. of Al2O3 media; the chemical etching process was conducted using HF-based mixed etchant. Sandblasting was performed in terms of variables such as the distance of 8 cm between the gun nozzle and the glass substrate, the fixed air pressure of 0.5bar, and the constant speed control of the specimen stage. The chemical etching process was conducted with mixed etching solution prepared by combination of BHF (Buffered Hydrofluoric Acid), HCl, and distilled water. The morphology of the glass surface after sandblasting process displayed sharp collision vestiges with nonuniform shapes that could initiate fractures. The haze values of the sandblasted glass were quantitatively acceptable. However, based on visual observation, the desirable Anti-Glare effect was not achieved. On the other hand, irregularly shaped and sharp vestiges transformed into enlarged and smooth micro-spherical craters with the subsequent chemical etching process. The curvature of the spherical crater increased distinctly by 60 minutes and decreased gradually with increasing etching time. Further, the spherical craters with reduced curvature were uniformly distributed over the etched glass surface. The haze value increased sharply up to 55 % and the transmittance decreased by 90 % at 60 minutes of etching time. The ideal haze value range of 3~7 % and transmittance value range of above 90 % were achieved in the period of 240 to 720 minutes of etching time for the selected concentration of the chemical etchant.
        4,000원
        96.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 인공광 광질에 따른 곰보배추의 생육, 엽형 및 항산화능을 비교하였다. 정식 후 56일째에 측정 된 엽장, 엽폭 및 엽수는 적색 LED(R)와 대조구인 형광등(FL) 처리구에서 유의적으로 높았고 혼합광(RB2:1)과 백색 LED(W) 처리구에서 낮았다. 엽형지수(엽장/엽폭)도 적색 LED(R)와 대조구인 형광등(FL) 처리구에서 유의적으로 높았고 혼합광(RB2:1)과 백색 LED(W) 처리구에서 낮았다. 지상부 생체중, 건물중 및 엽면적 모두 적색 LED(R) 처리구에서 가장 높았고 형광등(FL)과 청색 LED(B) 처리구가 그 다음으로 높게 나타났으며 혼합광 (RB2:1)과 백색 LED(W) 처리구에서 낮았다. 잎의 수하 현상은 정식 21일 이후부터 적색 LED(R)와 혼합광 (RB2:1) 처리구에서만 발생하였다. 엽록소 함량은 적색 LED(R) 처리구에서 가장 낮았다. 비엽중은 청색 LED(B) 처리구에서 가장 높았고 형광등(FL) 처리구에서 가장 낮았다. DPPH free radical 소거활성은 처리 간 유의차가 없었다. 위의 결과들을 종합하여 볼 때 형광등이 곰보배추를 실내에서 인공으로 재배 시 적합한 광원으로 판단된다.
        4,000원
        97.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study was conducted to investigate the effects on growth performance, nutrient digestibility, and gut health of broiler chickens when a dietary supplementation of multienzymes was added to diets, containing different energy levels. A total of 480 broiler chickens of similar body weight (Ross 308, 1-day-old) were randomly subjected to four treatments. The dietary treatments included a corn-soybean meal-based diet supplemented with: multienzyme (amylase+protease+ mannanase+xylanase+phytase), 0.05% enzyme, and different energy levels (3010 and 3060 kcal/kg). The experimental diets were fed to the chicks in a mash form for 35 days in two phases (1–21 d, phase I; and 22–35 d, phase II). During the overall period, chicks fed with diets supplemented with multienzymes had a better weight gain (p<0.05) and feed conversion ratio (FCR) than those fed with diets without enzymes. There was no difference in the growth rate and FCR among the chicks fed with diets supplemented with enzymes, even though the dietary energy levels were different. The apparent fecal and ileal digestibility of dry matter, gross, crude protein, calcium, and phosphorus were significantly enhanced (p<0.05). The population of cecal and ileal Lactobacillus spp. was significantly increased (p<0.05), and Clostridium spp. and coliforms were significantly decreased (p<0.05) in diets supplemented with enzymes. Villus height and villus height to crypt depth ratio in the small intestine was also significantly enhanced (p<0.05) in diets supplemented with enzymes. In conclusion, multienzyme supplementation had positive effects on the weight gain of broilers, FCR, digestibility of nutrients, and on the growth of intestinal microbiota.
        4,200원
        98.
        2017.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The environmental dependence of the morphology of dwarf galaxies in isolated satellite sys- tems is analyzed to understand the origin of the dwarf galaxy morphology using the visually classified morphological types of 5836 local galaxies with z . 0.01. We consider six sub-types of dwarf galaxies, dS0, dE, dEbc, dSph, dEblue, and dI, of which the first four sub-types are considered as early-type and the last two as late-type. The environmental parameters we consider are the projected distance from the host galaxy (rp), local and global background densities, and the host morphology. The spatial distributions of dwarf satellites of early-type galaxies are much different from those of dwarf satellites of late-type galaxies, suggesting the host morphology combined with rp plays a decisive role on the morphology of the dwarf satellite galaxies. The local and global background densities play no significant role on the morphology of dwarfs in the satellite systems hosted by early-type galaxies. However, in the satellite system hosted by late-type galaxies, the global background densities of dE and dSph satellites are significantly different from those of dEbc, dEblue, and dI satellites. The blue-cored dwarf satellites (dEbc) of early-type galaxies are likely to be located at rp > 0.3 Mpc to keep their cold gas from the ram pressure stripping by the hot corona of early-type galaxies. The spatial distribution of dEbc satellites of early-type galaxies and their global background densities suggest that their cold gas is intergalactic material accreted before they fall into the satellite systems.
        4,600원
        99.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Selective laser melting (SLM) can produce a layer of a metal powder and then fabricate a three-dimensional structure by a layer-by-layer method. Each layer consists of several lines of molten metal. Laser parameters and thermal properties of the materials affect the geometric characteristics of the melt pool such as its height, depth, and width. The geometrical characteristics of the melt pool are determined herein by optical microscopy and three-dimensional bulk structures are fabricated to investigate the relationship between them. Powders of the commercially available Fe-based tool steel AISI H13 and Ni-based superalloy Inconel 738LC are used to investigate the effect of material properties. Only the scan speed is controlled to change the laser parameters. The laser power and hatch space are maintained throughout the study. Laser of a higher energy density is seen to melt a wider and deeper range of powder and substrate; however, it does not correspond with the most highly densified three-dimensional structure. H13 shows the highest density at a laser scan speed of 200 mm/s whereas Inconel 738LC shows the highest density at 600 mm/s.
        4,000원
        100.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Body scales directly exposed to external environments can be an important factor to understand various characteristics of a species such as habitat features, life history and basic ecology. In this study, we compared size and morphology of dorsal, outermost dorsal, keeled dorsal and ventral scales of total nine snake species in Korea; Oocatochus rufodorsatus, Elaphe dione, Rhabdophis tigrinus, Amphiesma vibakari, Dinodon rufozonatum, Hierophis spinalis in the Colubridae and Gloydius ussuriensis, G. brevicaudus, G. saxatilis in the Viperidae. The morphological characteristics of the scales seem to well reflect foraging modes and moving activity of both families. Uniquely D. rufozonatum had a diamond shape dorsal scale and had the greatest and smallest value of the ratio of width/length of dorsal and ventral scales, respectively. O. rufodorsatus, D. rufozonatum and H. spinalis did not have keeled dorsal scales and E. dione had keel on the few of dorsal scales. In addition, morphological characteristics of scales of three viper species were closely consistent with previously known phylogenetic relationships.
        4,000원
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