• Environmental Engineering Research
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• 제12권3호
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• pp.109-117
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• 2007

The characteristics of carbonaceous particles collected from the combustion of Vacuum Residue (VR) in a test furnace have been investigated. The physical and chemical characterization includes particle size, scanning electron microscopy of the surface structure, measurement of porosity, surface area and density, EDX/XRD analyses and measurement of chemical composition. The studies show that the carbonaceous VR particles are very porous and spheroidal, and have many blow-holes on the surface. The particles become smaller and more sponge-like as the reaction proceeds. The present porosity of VR particles is similar to that of cenospheres from the combustion of heavy oil, and the majority of pores are distributed in macro-pores above $0.03\;{\mu}m$ in diameter. Measurements of pore distribution and surface area showed that the macro-pores contributed most to total pore volume, whereas the micro-pores contributed to total surface area.

• 한국염색가공학회지
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• 제15권2호
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• pp.68-75
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• 2003

In this work, ultrafiltration(UF) membranes were prepared using polyethersulfone(PES). The polymer was dissolved in various solvent, such as N, N-dimethyl formamide(DMF), N,-dimethyl acetamide (DMAc), N,N-dimethyl sulfoxide(DMSO) and N-methyl-2- pynolidone(NMP). Each polymer solution was casted on the glass plate, and immersed into non-solvent bath. In this way finely porous UF membranes were prepared by phase inversion method. The cross sectional structure of PES membrane was asymmetric which was consist of sponge-like sublayer, finger-like toplayer, and active skin layer. From the solute rejection experiments, the molecular weight cut off of the prepared membrane in various solvent was evaluated 10,000 for DMF, 30,000 for DMAc, 50,000 for DMSO, and 10,000 for NMP respectively.

• Animal Systematics, Evolution and Diversity
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• 제27권1호
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• pp.19-23
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• 2011

Two new marine sponges, Halichondria jangseungenesis n. sp. and H. nagokenesis n. sp., of the family Halichondriidae, were collected from Uljin-gun, Gyeongsangbuk-do, Korea by SCUBA diving during the period from Apr 2007 to Aug 2007. Based on their spicule composition and skeletal structure, H. jangseungenesis n. sp. appears to have a close similarity with H. panicea (Pallas, 1766); however, they differ in length of spicule. The spicule length of oxea of H. jangseungenesis n. sp. is shorter than that of H. panicea. Based on their spicule composition and growth form, H. nagokenesis n. sp. is quite similar to H. cylindrata Tanita and Hoshino, 1989; however, but they differ in length of spicule. The spicule length of oxea of H. nagokenesis n. sp. is longer than that of H. cylindrata.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.258-265
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• 2000

This study is to develop a Fe-based disc brake tinning with sponge structure for passenger car of 150km/h train and to concept design with 3 groove type for brake disc reducing hot hair-crack and certainly friction coeifficient. The developping brake linning would be to presumption of thermal stress Max.5.53k9/m0 of the 3 groove type. and It is stable friction coeifficient and wear rate on the Full Scale Brake dynamometer. So 3 groove type must be reduced to hot stress between Brake disc and Linning and Friction temperature is reduced about 20$^{\circ}C$

• Animal Systematics, Evolution and Diversity
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• 제36권2호
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• pp.143-153
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• 2020

Six new species of two genera Dysidea and Pleraplysilla (Demospongiae: Dictyoceratida: Dysideidae) are described from Jejudo Island, Dokdo Island and Guryongpo, Korea. Among them, five new species of the genus Dysidea are compared with other reported species in fibres structure, cored detritus and fibres arrangement. Dysidea niveus n. sp. is characterized by thin collagenous plate-like fibres. Dysidea dokdoensis n. sp. is similar to D. geomunensis Kim et al., 2020 in skeletal structure, but differs in length of surface conules. Dysidea hydra n. sp. is similar to D. mureungensis Kim et al., 2020 at the surface, but differs in fibres cored with spicules. Dysidea sabulum n. sp. is similar to D. glavea Kim et al., 2020 in cored large sands in fibres, but differs in having numerous large sands cored in fibres throughout the sponge. Dysidea hirsuta n. sp. is unique, only surface fibres cored with large sands but not in choanosome. A new species of genus Pleraplysilla, P. flabellum n. sp. is compared with seven other reported species. This new species is not encrusting but has a thick flabellate shape.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.56.2-56.2
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• 2012

Clinically-favored materials for bone regeneration are mainly based on bioceramics due to their chemical similarity to the mineral phase of bone. A successful scaffold in bone regeneration should have a 3D interconnected pore structure with the proper biodegradability, biocompatibility, bioactivity, and mechanical property. The pore architecture and mechanical properties mainly dependent on the fabrication process. Bioceramics scaffolds are fabricated by polymer sponge method, freeze drying, and melt molding process in general. However, these typical processes have some shortcomings in both the structure and interconnectivity of pores and in controlling the mechanical stability. To overcome this limitation, the rapid prototyping (RP) technique have newly proposed. Researchers have suggested RP system in fabricating bioceramics scaffolds for bone tissue regeneration using selective laser sintering, powder printing with an organic binder to form green bodies prior to sintering. Meanwhile, sintering process in high temperature leads to bad cost performance, unexpected crystallization, unstable mechanical property, and low bio-functional performance. The development of RP process without high thermal treatment is especially important to enhance biofunctional performance of scaffold. The purpose of this study is development of new process to fabricate ceramic scaffold at room temperature. The structural properties of the scaffolds were analyzed by XRD, FE-SEM and TEM studies. The biological performance of the scaffolds was also evaluated by monitoring the cellular activity.

• 한국분말재료학회지
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• 제17권3호
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• pp.209-215
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• 2010

Mesoporous alumina particles were prepared by spray pyrolysis using cetyltrimethyl-ammonium bromide (CTAB) as a structure directing agent and the effect of Al precursor types on the texture properties was studied using $N_2$ adsorption isotherms, small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The surface area and the microstructure of alumina particles were significantly influenced by the Al precursor type. The largest BET surface area was obtained when Al chloride was used, whereas alumina particles prepared from Al acetate had the largest pore volume. According to small-angle X-ray scattering (SAXS) analysis, the alumina powders prepared using nitrate and acetate precursors had a clear single SAXS peak around $2{\theta}=1.0{\sim}1.5^{\circ}$, indicating that regular mesopores with sponge-like structure were produced. On the basis of TEM, SAXS, and $N_2$ isotherm results, the chloride precursor was most profitable to obtain the largest surface area ($265\;m^2/g$), whereas, the nitrate precursor is useful for the preparation of non-hollow mesoporous alumina with regular pore size, maintaining high surface area (${\sim}233\;m^2/g$).

• Membrane and Water Treatment
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• 제13권4호
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• pp.173-181
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• 2022

Polyvinylidene fluoride (PVDF) flat sheet hydrophobic membranes were prepared using 16 wt% PVDF in Dimethyl acetamide (DMAc) by phase inversion technique for desalination application using Membrane Distillation (MD). In this work, the effect of coagulation mediums such as ethanol and water as well their synergistic behavior on the fabricated PVDF membrane morphology was studied using SEM. Moreover, other characteristics required for the membrane distillation applications namely porosity, hydrophobicity and tensile strength were measured using the gravimetric method, sessile drop method and universal testing machine respectively. It was observed that the membrane morphology paradigm shifted from the finger-like structure to the sponge-like structure on increasing the ethanol concentration in coagulant. The porosity of the fabricated membrane was under the required MD range and found to be 57.3% at 16 weight % of PVDF in DMAc solvent under a pure ethanol coagulant bath. Moreover, the top surface contact angle ranges from 85° to 115° on increasing the bath concentration from CBC 0 to CBC 100 at 16 weight % of PVDF in DMAc solvent.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 추계국제학술대회
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• pp.16-44
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• 2020

Cancer is the second leading cause of death in the world. According to the 2018 reports, one in six people worldwide is reported to die as a result of cancer. The discovery of anticancer drugs has been utilized extensively, but there has been no report on excellent selective activity in cancer cells. The discovery of bioactive substances from marine sponges has been the limelight in the pharmaceutical field over the past decade owing to the production of many bioactive compounds from the sponges to protect themselves against the environment. On top of that, marine sponges also produced cytotoxic compounds such as terpenoids, alkaloids, steroids, and peptides which suggests that marine sponges have high potential in the development of anticancer drugs. Thus, this study aimed to obtain new cytotoxic compounds from S. siphonella in Egypt and Arenoscelra sp. and Gelliodes sp. in Vietnam, and further investigation of the extract from these marine sponges led to isolation of ten new compounds and 21 known compounds. Chapter 1 will discuss about the isolation and structure elucidation of eight new polyacetylene derivatives from S. siphonella and their cytotoxic activities. The isolation and structural elucidation of one new polybrominated iododiphenyl ether from Arenosoclea sp. as well as cytotoxic activities of the isolated compounds will be reported in chapter 2. Finally, isolation and structure elucidation of new compounds from the marine sponge Gelliodes sp. and their cytotoxic activities will be discussed in chapter 3.

• Membrane and Water Treatment
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• 제1권3호
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• pp.215-230
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• 2010

Poly(vinylidene fluoride-co-hexafluoropropylene), PVDF-HFP, hollow fiber membranes were prepared by the dry/wet spinning technique using different polyethylene glycol (PEG) concentrations as non-solvent additive in the dope solution. Two different PEG concentrations (3 and 5 wt.%). The morphology and structural characteristics of the hollow fiber membranes were studied by means of optical microscopy, scanning electron microscopy, atomic force microscopy (AFM) and void volume fraction. The experimental permeate flux and the salt (NaCl) rejection factor were determined using direct contact membrane distillation (DCMD) process. An increase of the PEG content in the spinning solution resulted in a faster coagulation of the PVDF-HFP copolymer and a transition of the cross-section internal layer structure from a sponge-type structure to a finger-type structure. Pore size, nodule size and roughness parameters of both the internal and external hollow fiber surfaces were determined by AFM. It was observed that both the pore size and roughness of the internal surface of the hollow fibers enhanced with increasing the PEG concentration, whereas no change was observed at the outer surface. The void volume fraction increased with the increase of the PEG content in the spinning solution resulting in a higher DCMD flux and a smaller salt rejection factor.