• Journal of the Microelectronics and Packaging Society
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• v.11 no.3 s.32
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• pp.47-53
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• 2004

Eutectic Au-20Sn(compositions are all in weight percent unless specified otherwise) solder alloys were soldered on the Ni substrate with various time and temperature. The composition, phase identification and morphology of intermetallic compounds(IMC) at the interface were examined using Scanning Electron Microscopy(SEM). There were two types of IMCs, $(Au,Ni)_3Sn_2$ and $(Au,Ni)_3Sn$ at the interface. The transition in morphology of $(Au,Ni)_3Sn_2$ has been observed at $300{\~}400^{\circ}C$. The morphology transition of $(Au,Ni)_3Sn_2$ is due to the decrease of enthalpy of formation of $(Au,Ni)_3Sn_2$ phase and has been explained well by Jackson's parameter with temperature. Because the number of diffusion channel is different at each soldering temperature, IMC thickness is nearly same at all temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.714-719
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• 2017

The controlled synthesis of inorganic materials with a specific size and morphology is an important factor in the development of new materials in many fields, such as nanoparticles, medicine, electronics, semiconductors, pharmaceutical sand cosmetics. Solution crystallization is one of the most widely used separation processes in the chemical and pharmaceutical industries. Calcium carbonate has attracted a great deal of attention in industry because of its numerous applications. The mean crystal size, crystal size distribution and morphology are important factors in the continuous crystallization process. In this study, the continuous crystallization of calcium carbonate by the calcium chloride process was investigated. The mean crystal size and crystal size distribution data were obtained by a particle size analyzer. The morphological imaging of the crystalswasper formed by SEM. Under steady state operation, the mean crystal size change was small, but increasing the input concentration and mixing rate increased the crystal size. In this operation, some aragonite was found, but the main crystal phase was calcite.

• Clean Technology
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• v.19 no.3
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• pp.272-278
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• 2013

Ethylene propylene diene terpolymer (EPDM) has been usually used for various applications. Bottom ash generated in thermoelectric power plant is hardly recycled. In this study, EPDM/bottom ash/talc composites were prepared by using roll-mill. Bottom ashes obtained from thermoelectric power plant were modified using surfactant. The processing materials used in this study were antioxidant, processing oil, cross-linking co-agent and softening agent. Morphology and physical properties of EPDM composites are investigated by using SEM, TGA, UTM and Rheometer. As a result, when modified ash and talc are added to EPDM composites, the tensile strength and modulus of EPDM composites were remarkably enhanced.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.1007-1018
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• 2019

In the present study, according to morphological observations followed by recent circumscriptions, we have classified the Korean taxa of the family Linderniaceae into Scrophulariaceae sensu lato has been considered in several works, though the taxa have remained undefined because identification work was mostly done according to vegetative morphological features, such as the leaf shape, leaf margins, and leaf venation. The taxa of Linderniaceae are mostly considered to be weeds and, for correct identification, it is necessary to clarify their taxonomic characteristics. Morphological studies were carried out using samples collected in the field. Micro-morphological observations of the vegetative and floral parts were also performed using light microscopy (LM) and scanning electron microscopy (SEM). We concluded that important characteristics are reproductive morphologies viz. calyx, stamen structure, capsule shape, calyx ratio with capsule, inflorescence morphology, and seed morphology. As a result, we formulated taxa descriptions and provided a key of the genera of Linderniaceae in Korea. Lindernia crustacea (L.) F. Muell. is transferred to Torenia crustacea (L.) Cham. & Schltdl. Lindernia micrantha D. Don and L. angustifolia (Benth.) Wettstein are a synonym of Vandellia micrantha (D. Don) Eb. Fisch., Schäferh. & Kai Müll. Lindernia attenuata Muhl. and L. dubia var. major (Pursh) Pennell are a synonym of Lindernia dubia (L.). Lindernia verbenifolia (Colsm.) Pennell is a synonym of Bonnaya antipoda Druce. Our study reports the presence of four genera: Bonnaya, Lindernia, Torenia, and Vandellia, comprising six taxa under the family Linderniaceae in Korea.

• Polymer(Korea)
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• v.26 no.6
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• pp.759-766
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• 2002

Regular, spherical and isotropic open-microcellular foams having low density were prepared by the high internal phase emulsion (HIPE) polymerization mainly composed of styrene monomer and water The effects of Polymerization conditions. such as the content of water, divinylbenzene as a crosslinking agent and dodecane as a chain transfer agent, were investigated based on the tell size and foam properties. The microstructural morphology was observed using scanning electron microscopy (SEM) and the compression modulus of the foam was evaluated using compression test. The dropwise feeding of the aqueous phase into the oil phase was more effective than the batch feeding in producing the uniform and stable foam. Agitation speed and surfactant strongly influenced on the cell size and the window size between water droplets. Introduction of chain transfer agent increased the cell size, whereas it decreased the window size. Compression modulus increased with the crosslinking agent, but decreased with the chain transfer agent.

• Journal of the Mineralogical Society of Korea
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• v.1 no.2
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• pp.117-130
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• 1988

The morphology of the Ca-montmorillonites from the Gampo area was investigated by the use of scanning and transmission electron microscope. These bulk samples show an irregular or rugged surface with well developed cavities and relict outline of original ash material at low magnification by SEM, indicating that montmorillonites are derived from volcanogenic material. Two different types of morphology of montmorillonites by SEM were observed which appear to depend very much on the space available for crystal growth. One is honeycomb structure montmorillonite growing in an open space. The other is the closely packed aggregates of intergrown montmorillonite showing platy particles where available space for the growth is limited. Several different habits of montmorillonite within a single sample can be observed by TEM. The dominant habit observed is the irregularly shaped and foliated aggregates and the platy shaped particles. In general, platy shaped particles are relatively abundant in the samples from Yongdongri compared with those from Jugjeonri area.

• Korean Journal of Plant Taxonomy
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• v.33 no.4
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• pp.411-420
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• 2003

To examine the seed morphology in Korean Orobanchaceae, seeds of 5 species including 1 variety in five genera and one related taxon, Boschniakia himalaica Hook. f. & Thomson in Hook. f. from the Himalaya (7 taxa in total) were investigated by scanning electron microscopy (SEM). Two different seed types are recognized depending on three characters (e.g, .the seed size, seed coat structure and seed number per fruit). - Type I: size less than 1mm, seed coat structure reticulate and seed number per fruit more than ca. 1,000; Type II: size more than 1 mm, exotesta irregularly crested and seed number per fruit less than 1,000 (Lathraea japonicu Miq.). In Type I, three subtypes of exotesta internal surface pattern can also be classified; (1) Subtype Ia: reticulate - include irregularly striate (Ia') and deeply reticulate (Ia"), (2) Subtype Ib: foveolate, (3) Subtype Ic: smooth. Systematics application of the seed morphological data for the Korean Orobanchaceae is also briefly discussed.

• Journal of the Korean Vacuum Society
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• v.6 no.3
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• pp.242-248
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• 1997

Porous silicons were prepared by dry etching as well as by chemical etching. The latter is a conventional method used by many researchers. Meanwhile, the former is a new method we developed. Also the porous silicon structure was made by E-beam lithography technique. However, due to the limit of this technique, minimum size we could produce was about 0.3 $\mu\textrm{m}$ in diameter on silicon wafer. In a new method, the porous silicon microstructure was fabricated by using Reactive Ion Etching method after covering with diamond powder on 4 inch wafer by using spin coater. In this method, diamond powder acted as a mask. The morphology of samples prepared under many different conditions were analysed be SEM and AFM. And we measured PL spectra for the samples. Based on these results, we observed the structure of a few hundreds $\AA$ in size from porous silicon which was made by dry etching with diamond powder. Also the PL peak for these samples lied around 590 nm compared to 760 nm for chemically etched porous silicon.

• Journal of Surface Science and Engineering
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• v.49 no.3
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• pp.260-264
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• 2016

In this study, fractured surface morphology and mechanical properties of Ni-Cr-Mo alloys with various contents of Mo for dental material use have been evaluated by mechanical test. The alloys used were Ni-13Cr-xMo alloys with Mo contents of 4, 6, 8, and 10 wt.%, prepared by using a vacuum arc-melting furnace. Ni-13Cr-xMo alloys were used for mechanical test without heat treatment. The phase and microstructure of alloys using an X-ray diffraction (XRD) and optical microscopy (OM) were evaluated. To examine the mechanical properties of alloys according to microstructure changes, the tensile test and the hardness test were carried out using tensile tester. To understand the mechanism of Mo addition to Ni-Cr alloy on mechanical property, the morphology and fractured surfaces of alloys were investigated by field-emission scanning electron microscope (FE-SEM). As a result, 79Ni-13Cr-8Mo alloy was verified that the tensile strength and the hardness were better than others. Varying Mo content, the changes of microstructures of alloys were identified by OM and SEM and that of 79Ni-13Cr-8Mo alloy was proved fabricated well. Microstructures of alloys were changed depending on Mo content ratio. It has been observed that 8% alloy had the most suitable mechanical property for dental alloy.

• Korean Journal of Plant Taxonomy
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• v.36 no.1
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• pp.1-19
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• 2006

Description of spore morphology of Korean Polypodiaceae has on LM and SEM and key to the genera are provided. Korean Polypodiaceae monad, monolete with bilateral symmetry, bipolar and oblete spore except for Loxogramme grammitoides having trilete spore with radial symmetry. In spore wall structure, exopore showed variable patterns enough to distinguish genera. Perispore was found in all the species examined. The patternof perispore and exospore was most similar in all the species examined except Crypsinus, Pyrrosia hastata ans P. linearifolia. The perispores of Crypsinus, Pyrrosia hastata and P. linearifolia were echinate and gemmate, rugulate, and verrucate respectively. In term of exospore wall sculpturing, Polypodium and Loxogramme showed fossulate, Lepisorus, rugulate with irregular verrucate, Crypsinus ans Coloysis showed psilate or rarely verrucate in the latter, Neocheiropteris ensata showed dense small verrucate, Lemmaphyllum microphyllum showed complex reticulate and Pyrrosia showed verrucate or psilate.