• 환경생물
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• 제34권3호
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• pp.141-150
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• 2016

Most previous studies on dinoflagellates in Korean coastal areas were conducted without morphological descriptions and illustrations of the observed dinoflagellates. This indicates that the species and diversity of dinoflagellates may have been respectively misidentified and underestimated in the past, probably due to cell shrinkage, distortion and loss caused by sample fixation. This study provides information on the morphological observations of four dinoflagellate orders (Prorocentrales, Dinophysiales, Gonyaulacales and Gymnodiniales) from Jangmok Harbour in Jinhae Bay, Korea. The unfixed samples were collected weekly from December 2013 to February 2015. A total of 13 genera and 30 species were identified using light and scanning electron microscopy, although some samples were not clarified at the species level. Harmful dinoflagellates, Prorocentrum donghaiense, Tripos furca, Alexandrium affine, A. fundyense, Akashiwo sanguinea and Cochlodinium polykrikoides, were identified based on the morphological observations. The results also reflect the occurrence and identification of dinoflagellates that had not been previously recorded in Jangmok Harbour.

• 한국염색가공학회지
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• 제8권4호
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• pp.42-51
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• 1996

Alkaline hydrolysis to improve the hand of PET/acetate union fabric was studied in relation to skin saponification and retarding effect of salts on the alkaline hydrolysis of cellulose acetate fiber, accelerating effect of salts on the alkaline hydrolysis of PET fiber, and changes of total hand value(T.H.V) of PET/acetate union fabric treated with alkali/salt solution. It was found that the rate of saponification of acetate was delayed by the addition of salts such as LiCl, NaCl and CH$_{3}$COONa into NaOH solution below 10 minutes. The rate of shrinkage of acetate fabric treated with 5g/l NaOH solution at 9$0^{\circ}C$ and 60 minutes showed 20 % but it was decreased 8% by. the addition of 120g/l Concentration of inorganic salts. We could know that the rate of alkaline hydrolysis of filament yarn treated with alkali solution at 9$0^{\circ}C$ and 60 minutes was delayed about 3 % using 2,000T/M of hard twist yarn, especially acetate filament treated with alkali solution at 9$0^{\circ}C$ and 10 minutes was delayed about 10%. T.H.V. of PET/acetate union fabric was increased from 2.77 to 3.04~3.18 by the addition of salts into alkali solution.

• Advances in materials Research
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• 제4권1호
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• pp.45-60
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• 2015

This paper aimed to investigate the effect of MWCNTs on properties of slag Geopolymeric mortar. Geopolymeric matrices containing different MWCNTs concentrations (0.0, 0.1, 0.2, 0.3 and 0.4 % by weight of the used binder) were synthesized. The Geopolymer mortar composed of aluminosilicate slag to sand (1:2), while the alumino silicate source binder composed of 50% air cooled slag and 50%water cooled slag both passing a sieve of $90{\mu}m$, while the sand passing a sieve of 1 ml. The materials prepared at water/binder ratios in a range of 0.34-0.39% depending on the added MWCNT, whereas the Gelenium Ace-30 superplasticizer used in the ratio of 1.4-2.2% from the total dry weight for better dispersion of MWCNT under sonication for 15 min. Alkaline activation of the Geopolymer mortar was carried by using of 6% NaOH. Curing was performed under temperature of $40^{\circ}C$ and 100% R.H. Results showed that the addition of MWCNTs enhanced the resulting amorphous geopolymer structure with marked decrease in the drying shrinkage as well as water absorption specially when using 0.1% MWCNT, while further increase in MWCNTs results in agglomeration in MWCNT within the matrix and so hinder the propagation of Geopolymerization reaction and negatively affect the formed geopolymer structure.

• 대한기계학회논문집
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• 제18권5호
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• pp.1310-1321
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• 1994

Turbulent coherent structures in the intermediate wake of a stationary and rotating cylinder, spin rate S=0.7, situated in a uniform were experimentally investigated using a conditionalphase average technique. Measurements were carried out at a section of 8.5 diameters downstream form the center of cylinder and a Reynolds number of $Re=6.5{\times}10^{3}.$/TEX> The phase averaged velocity and velocity vector fields, contours of vorticity, turbulent intermittency function and velocity fluctuation energy are presented and discussed in relation to the large scale coherent structures by Karman vortices that shed periodically from the cylinder. Coherent wake structures of the rotating cylinder is almost identical with stationary cylinder, but the lateral displacement and shrinkage of turbulent wake region is occured by rotation. Rotation of the cylinder result in that the deflection of wake center to deceleration region(Y/D${\simeq}-0.3)$ and the decrease of mean velocity defect(10%), vorticity strength of large scale structures(19%), total velocity fluctuation energy(12%).

• 한국식품영양과학회지
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• 제27권4호
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• pp.675-681
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• 1998

Low density polyethlene(LDPE0 films of 50${\mu}{\textrm}{m}$ thickness were fabricated with addition of antimicrobial agents of Rheum palmatum extract, Coptis chinensis extract, sorbic acid and Ag-substitude inorganic zirconium matrix in 1% concentration. The films were compared in physical properties, tested in antimicrobial activity against some selected microorganisms on the agar plate medium and then applied for packaging fresh curled lettuce and cucumber to preserve their qualities. The films with Rheum palmatum extract, Coptis chinensis extract, and Ag-substituted inorganic zirconium matrix did not show any antimicrobial activity on the disk test against Escherichia coli, Staphylococcus aureus, Leuconostoc mesenteroides, Saccharomyces cerevisiae, Aspergillus niger, Aspergillus oryzae, Penicilluium chrysogenum, while film with sorbic acid did against E. coli, S. aureus and L. mesenteroides. The added antimicrobial agents changed the color and light transmittance of the films, but did not affect their mechanical tensile strength, heat shrinkage and wettability. For the packaged curled lettuce and cucumber stored at 5$^{\circ}C$ and 1$0^{\circ}C$, all the LDPE films impregnated with antimicrobial agents showed the reduced growth of total aerobic bacteria in the vegetables compared with control film without any additive until it reached the level around 108/g. They did not give any negative effect on other quality attributes during storage.

• 한국응용곤충학회지
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• 제31권4호
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• pp.366-370
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• 1992

벼멸구 수컷 정소에서 염색체의 변이정도를 생태형 별로 관찰하였다. 세포 분열 지수는 생태형 3에서 가장 높았고 그 다음으로 생태형 1, 생태형 2이었다. Agmatoploidy, aneuploidy, 성염색체의 loose pairings과 같은 염색체의 구조적 변화는 생태형 1, 생태형 2, 생태형 3순으로 높았다. 감수분열 제1분열기 중기는 성염색체가 상염색체로부터 현격하게 분리되어 있는 세포의 수는 생태형 2에서 가장 높았다.

• 한국건설순환자원학회논문집
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• 제3권1호
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• pp.72-79
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• 2007

This study investigates the engineering properties of concrete incorporating lime stone crushed fine aggregate(Ls), which has been abandoned about 20% of total production due to the low purity. Test results showed that increase of Ls had favorable fluidity and slightly decreased air content. Bleeding capacity of all specimens was not appeared as those were high strength mixture proportion, but the specimens using more Ls accelerated initial and final setting. For the mechanical properties, specimens incorporating higher ratio of Ls, overall, resulted in increase of compressive strength, and exhibited very small inclined tendency in a dynamic elasticity modulus test In addition, for the durability properties, specimens incorporating higher Ls dramatically decreased a drying shrinkage and showed similar tendency in a frost & thaw test, as well as showing no more change in an accelerated neutralization test from the beginning. In conclusion, as it was confirmed in the experimental test, the high strength concrete applying Ls did not showed any problems in the aspects of engineering properties and mostly exhibited even more excellent quality than the specimens using natural fine aggregate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.119-120
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• 2008

ILD CMP process has been well accepted for the planarization of the dielectric oxide film and becomes a critical process in ULSI manufacturing due to the rapid shrinkage of the design rule for the device. In total manufacturing process steps for a device, the proportion of ILD CMP process has been gradually increased. Ever since ILD CMP has been introduced, the scratches have been a major defects on polished surfaces which cause the electrical shorts between vias or metal lines [1,2]. It was reported that micro-scratches are caused by large, irregularly shaped particles during CMP process. Therefore, most of the CMP users have used < 5 m POU filter to remove and reduce the scratch source from the slurry. However, the scratch has always been the biggest concern in ILD polishing whatever preventive actions are taken. Silica and ceria slurries are widely used for ILD CMP process. There are not much differences in generated scratches and their formation mechanism. In this study, the scratches were investigated as a function of polishing conditions with possible explanation on formation mechanism in ILD CMP.

• Geomechanics and Engineering
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• 제8권2호
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• pp.173-186
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• 2015

The rapid urbanization in Pakistan is creating a shortage of sustainable construction sites with good soil conditions. Attempts have been made to use rice husk ash (RHA) in concrete industry of Pakistan, however, limited literature is available on its potential to improve local soils. This paper presents an experimental study on engineering properties of low and high plastic cohesive soils blended with 0-20% RHA by dry weight of soil. The decrease in plasticity index and shrinkage ratio indicates a reduction in swell potential of RHA treated cohesive soils which is beneficial for problems related to placing pavements and footings on such soils. It is also observed that the increased formation of pozzolanic products within the pore spaces of soil from physicochemical changes transforms RHA treated soils to a compact mass which decreases both total settlement and rate of settlement. A notable increase in friction angle with increase in RHA up to 16% was also observed in direct shear tests. It is concluded that RHA treatment is a cost-effective and sustainable alternate to deal with problematic local cohesive soils in agro-based developing countries like Pakistan.

• KIEAE Journal
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• 제9권1호
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• pp.91-97
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• 2009

In this thesis presents the application to the field of Hwangto-used concrete highlighted as an eco-friendly material and performs an experiment in the aspect of construction and quality on the construction for all parts of buildings, rather than for some parts of buildings as shown from existing application and got the conclusion as followings. 1) It was turned out that Hwangto concrete showed lower hydrated heat and arid contraction comparing to those of cement concrete. And this phenomenon is judged to appear high when applied to mass building and huge span structures. 2) The construction of Hwangto concrete is judged to be possible in applying to constructions since the mechanical construction seems to be possible by using pump car and ready-mixed concrete which are used at the practical sites at the moment. 3) The pockmarks appearing on the exposure surface were about 2% of total area. This has great cohesion by Hwangto concrete but is judged that it will be improved through enough vibration stamping. Through the experiments of quality and construction of Hwangto concrete as environment-friendly construction materials, it is possible to judge modernized application of Hwangto concrete. It is in need of more studies about economical efficiency, structural stability, design application, etc. afterwards.