• Journal of the Korean Chemical Society
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• v.39 no.7
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• pp.559-563
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• 1995

The three metabolites, Germacrene alcohol(1), Aaptamine(2) and Hexacyclic terpene(3) were isolated from Marine Sponge Luffariella sp., collected in October 1992, Manado Bay, Sulawesi in Indonesia showed in vitro activity against KB cancer cell line, and structure assignment for 1 was corrected by comparison of their spectral data with the literature $values^1$. Their structure were elucidated by $^1H$, $^13C$ NMR, $^1H$ $^13C$(1 bond) Heteronuclear Multiple Quantum Coherence Spectroscopy$(HMQC)^2$, $^1H$ $^13C$(2 and 3 bond) Heteronuclear Multiple Bond Correlation Spectroscopy$(HMBC)^3$, Electron Impact Mass Spectroscopy(EI ms), Ultra-violet Spectroscopy(UV) and Infrared Spectroscopy(IR).

• Polymer(Korea)
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• v.39 no.1
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• pp.144-150
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• 2015

Gellan gum as a natural polysaccharide has good heat resistance, acid resistance and enzymes resistance. However, one of the drawbacks of gellan gum might be the lower mechanical strength. In this work, gellan gum scaffolds were mixed with poly(lactic-co-glycolic acid) (PLGA) microsphere in order to improve mechanical properties. The gellan gum scaffolds with various contents of PLGA microsphere were prepared for the regeneration of disc tissues. To evaluate the mechanical strength of hybrid structure of gellan gum and PLGA microsphere, compression strength of the fabricated scaffolds was measured. MTT analysis, SEM observation, histological evaluation and RT-PCR were performed to confirm the effect on the cell growth and extracellular matrix secretion. As a result, it showed the best cell proliferation and extracellular matrix secretion in gellan gum sponge containing 50% PLGA microspheres. In conclusion, this study confirmed that the hybrid structure of gellan gum and PLGA microspheres was found suitable in regeneration of the intervertebral disc.

• Membrane Journal
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• v.31 no.6
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• pp.456-470
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• 2021

In this study, polyetherimide-based hollow fiber membranes were manufactured using the NIPS (nonsolvent induced phase separation) method. THF, Ethanol, and LiNO₃ were used as additives to control the morphology of the PEI-hollow fiber membranes. Furthermore, for the development of a high hydrogen separation membrane, the spinning conditions were optimized through the characterization of SEM and gas permeance. As a result, as the content of THF increased, the hydrogen/carbon dioxide selectivity increased. However, the permeance decreased due to the trade-off relationship. When ethanol was added, a finger-like structure was shown, and when LiNO₃ was added, a sponge structure was shown. In particular, in the case of a hollow fiber membrane with an optimized PDMS coating layer, the permeance was 40 GPU and the hydrogen/carbon dioxide selectivity was 5.6.

• Animal cells and systems
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• v.8 no.3
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• pp.139-143
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• 2004

Two new species of the genus Psammocinia (Dictyoceratida, Irciniidae), P. conulosa n. sp. and P. ulleungensis n. sp., are described from Namhaedo Island and Ulleungdo Island, Korea. Psammocinia conulosa n. sp. seems to be close to both P. amodes Cook and Bergquist, 1998 and P. hawere Cook and Bergquist, 1996 on the basis of the skeletal structure. However, these three species are clearly separated by the following differences: Shape of P. amodes is spatulate and thin, with a broad blade narrowing to a semi-cylindrical stalk; P. hawere forms cups with a shallow excavated bowl, and attached to the substratum by a narrow base. The whole surface of the new species is very finely conulose. Psammocinia ulleungensis n. sp. is similar to P. gageoensis Sim and Lee, 2001 in shape, but this species is easily distinguished from P. gageoensis by the simple skeletal structure.

• Journal of Species Research
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• v.5 no.1
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• pp.31-48
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• 2016

Twelve new species of two genera Smenospongia and Cacospongia (Demospongia: Dictyoceratida: Thorectidae) are described from Gageodo Island and Ulleungdo Island, Korea. Of these, ten new species of the Smenospongia are distinguished from the other nine reported species of the genus by the skeletal structure and sponge colour. Primary fibres of the genus Smenospongia are mostly dense, dark colour, and invisible inside of fibres, but they are mostly cored detritus and echinated with spicules. Especially, the end of primary fibres at the surface shows densely cored with spicules. All these new species changed the colour. Two new species of the genus Cacospongia are compared with nine other reported species. In skeletal structure, primary fibres of the genus Cacospongia are light colour, visible inside and more heavily cored with spicules and sands. The skeleton of this genus has large meshes. The colour of the genus Cacospongia does not change.

• Journal of KSNVE
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• v.9 no.4
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• pp.822-827
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• 1999

The reduction of booming noise level and improvement of sound quality in the vehicle interior have been major fields of vehicle NVH for many years. In order to reduce the booming noise this paper proposed a system variable, which takes account of mode shapes and natural frequencies of the structural-acoustic system, measurement points and excitation frequency. By simplifying the system variable, the major contributors of panels inculding roof, roof lining, wind shield glasses, doors and floor to booming noise at a specific frequency was experimentally found. Also the relationships between structural modes of roof lining, one of the major contributors, and acoustic modes of compartment cavity were investigated from the viewpoint fo structure-borne noise. In addition, the roof lining was modified structurally by applying marble sponge to the gap between roof and roof lining. Asthe result of structural modification, the booming noise was reduce at target frequency.

• Journal of Species Research
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• v.6 no.2
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• pp.190-194
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• 2017

Two new species of the genus Luffariella (Dictyoceratida: Thorectidae), L. tubula n. sp. and L. koreana n. sp. were collected from Jeju-do, Korea. These species differ significantly from the previously reported five species in terms of shape and skeletal structure. L. tubula n. sp. has two categories in thickness of secondary fibres which were different from other species. L. koreana n. sp. is very similar to L. variabilis from Tahiti in skeletal structure, but differs in sponge shape with irregular branching and indistinct surface conules. Primary fibres of the two new species are separated from secondary and tertiary fibres.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.09a
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• pp.73-85
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• 1995

The asymmetric hollow fiber membranes were prepared by the wet spining of polyetherimide dope solution and the effect of hollow fiber structures on the permeation characteristics of carbon dioxide and nitrogen gases through these membrane were investigated. As the concentration of the $\gamma$-butyrolactone (GBL) in dope solution, acting as a swelling agent was increased, the structure of hollow fiber was changed from the finger to sponge type. The permeabilities of gases (CO$_{2}$, N$_{2}$) through these membrane were measured over the wide range of pressure under different temperature. The effect of water vapor on the permeabilities of gases was also investigated. The measured permeabilities showed the different characteristics depending on the structure of membranes. It was found that the flow through the pores were dominant over the polymers matrix. Blocking effect by water vapor in the pores of skin layer greatly improved the ideal separation factor of carbon dioxide/nitrogen.

• Journal of Surface Science and Engineering
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• v.18 no.4
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• pp.164-183
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• 1985

The microstructure of the zinc electrodeposits was investigated by changing the flow rate of electrolyte in zinc sulfate Bath. The cathode current efficiency increased with increasing flow rate of electrolyte. The preferred orientation of zinc electrodeposit changed from (11.2) texture to (10.3) or (10.1)+(10.2) texture with increasing current density in the range of flow rate, 0.2-1.2m/sec. The morphology of the deposits changed from the sponge deposit to the blocks of hexagonal crystallites packed together through the structures of find polycrystallite with increasing current density. The microstructure of the cross-section of the above deposits are granular structure and columnar structure respectively. The surface roughness of zinc electrodeposits decreased with increasing current density and flow rate of electrolyte.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.4
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• pp.237-242
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• 2008

The tunic of Styela clava(SCT) consists of a proteoglycan network. Regenerated cellulose films were prepared by solution casting and coagulation of SCT in N-methylmorpholine-N-oxide(NMMO)/$H_2O$(87/13 wt%). The crystalline structure of powdered SCT was primarily that of cellulose I. The crystalline structure of SCT films exhibited a cellulose II structure, similar to that of viscose rayon. Physical characterization of SCT films and fibers revealed an intrinsic viscosity($\eta$) of 6.35 dL/g, average molecular weight($M_w$) of 423,000 g/M, and fiber density of 1.50 $g/cm^3$ with a moisture regain and water absorption of 10.20% and 365%, respectively. The results were similar to those of cellulose films regenerated from wood pulp. Films prepared with 6 wt% SCT exhibited strong tensile strength, high water absorption, and a greater degree of elongation. Scanning electron micrographs(SEM) of film cross-sections showed a layered, sponge-like structure.