• 반도체디스플레이기술학회지
• /
• 제3권4호
• /
• pp.5-11
• /
• 2004

Optical properties of PET(Polyethylene terephthalate), PC(Polycarbonate), Acrylic resin and PE(Polyethylene) sheets were studied as a function of heat treating temperature of $60^{\circ}C$ to $150^{\circ}C$. By the heat treatment, optical properties of transmittance, absorbance, and reflectance showed a considerable change with different ways according to the materials. To understand the reason of optical property change, X-ray diffraction and surface morphology were also investigated. It was observed that small crystallite and pore that can cause scattering largely affect the transmittance. It was suggested that change of surface chemical bond induce the reflectance variation.

• 한국분말재료학회지
• /
• 제9권4호
• /
• pp.218-226
• /
• 2002

The purpose of the present study is to investigate the influence of thermal debinding and sintering conditions on the sintering behavior and mechanical properties of PIMed 316L stainless steel. The water atomized powders were mixed with multi-component wax-base binder system, injection molded into flat tensile specimens. Binder was removed by solvent immersion method followed by thermal debinding, which was carried out in air and hydrogen atmospheres. Sintering was done in hydrogen for 1 hour at temperatures ranging from 1000℃ to 1350℃ The weight loss, residual carbon and oxygen contents were monitored at each stage of debinding and sintering processes. Tensile properties of the sintered specimen varied depending on the densification and the characteristics of the grain boundaries, which includes the pore morphology and residual oxides at the boundaries. The sinter density, tensile strength (UTS), and elongation to fracture of the optimized specimen were 95%, 540 MPa, and 53%, respectively.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
• /
• pp.166-169
• /
• 2004

Microfiltration membranes were prepared from aromatic polyethersulfone (PES) polymer, using aprotic solvent (N-methyl-2-pyrrolidone, NMP) and non-solvent additive (2-methoxy ethanol, 2-ME) by the phase inversion co-process of the vapor-induced phase inversion (VIPI) and the nonsolvent-induced phase inversion (NIPI). According to the change of the additive amount, the solvent amount and the relative humidity, membrane characterization was studied. The non-solvent additive in casting solution played an important role in membrane morphology. During the vapor-induced phase inversion, the relative humidity led to water sorption on the surface of casting dope at which pore formation was generated. The prepared membranes were characterized by scanning electron microscope observations, measurements of capillary flow porometer and pure water flux (PWP). Also the thermodynamic and kinetic properties of membrane-forming system were studied through coagulation value, light transmittance and viscosity.

• Journal of Mechanical Science and Technology
• /
• 제20권10호
• /
• pp.1680-1690
• /
• 2006

As a promising and novel manufacturing technology, laser aided direct metal deposition (DMD) process produces near-net-shape functional metal parts directly from 3-D CAD models by repeating laser cladding layer by layer. The key of the build-up mechanism is the effective control of powder delivery and laser power to be irradiated into the melt-pool. A feedback control system using two sets of optical height sensors is designed for monitoring the melt-pool and real-time control of deposition dimension. With the feedback height control system, the dimensions of part can be controlled within designed tolerance maintaining real time control of each layer thickness. Clad nugget shapes reveal that the feedback control can affect the nugget size and morphology of microstructure. The pore/void level can be controlled by utilizing pulsed-mode laser and proper design of deposition tool-path. With the present configuration of the control system, it is believed that more innovation of the DMD process is possible to the deposition of layers in 3-D slice.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1996년도 춘계학술대회
• /
• pp.221-222
• /
• 1996

In order to prepare the porous hydroxyapatite (HA) ceramics with different porosity, interconnectivity, mechanical properties, surface chemistry and tissue response, several methods have been developed. Of the different forms of Porous HA ceramics which were prepared by various methods, only the coralline HA has undergone major clinical applications in orthopaedic, maxillofacial and ophthalmic surgery. In this study, totally synthetic macroporous HA ceramics with various pore size distribution were prepared. It is shown that the new reticulate HA ceramics, comprised of interconnected voids surmunded by a web of ceramic, have a morphology which mimics that of human trabecular bone.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
• /
• pp.372-372
• /
• 2007

Titanium oxide nanotube arrays were fabricated by the anodization of pure titanium thin film deposited at $500^{\circ}C$ on silicon substrates. The titania nanotubes were grown by anodization in nonaqueous-base electrolytes at different potentials between 5 V and 30 V. $TiO_2$ nanotube array with a small pore diameter of 40 nm and long titanium oxide layer of $4\;{\mu}m$ was obtained. The $TiO_2$ nanotube array was used as a porous electrode for quartz crystal microbalance (QCM). Nanoporous morphology of electrode will increase the sensitivity of microbalance.

• 소성∙가공
• /
• 제12권5호
• /
• pp.457-464
• /
• 2003

In the powder compact melting technique, proper precursor fabrication is very important because density distribution after foaming and foamability are determined during precursor fabrication process. The fabrication of the precursor has to be performed very carefully because any residual porosity or other defects will lead to poor results in further processing. In order to evaluate the effect of the compaction parameters on the kinetics of the foaming process, a series of experiments were performed. In this study, aluminium foams with a closed cell structure were fabricated by using both the powder compact method and the induction heating process. A proper induction coil was designed to obtain a uniform temperature distribution over the entire cross sectional area of precursor. To establish the foamable precursor fabrication conditions, effects of process parameters such as the titanium hydride content (0.3∼1.5 wt.%), pressing pressure of the foamable precursor (50∼150kN) on the pore morphology were investigated.

• Mycobiology
• /
• 제46권4호
• /
• pp.311-316
• /
• 2018

Amylosporus sulcatus sp. nov. is described from Nonggang Nature Reserve, southern China, on the basis of morphological and molecular data. The morphological description and illustrations for the new species are provided. The species is characterized by pileate and stipitate basidiocarps. The pileus surface is obviously concentrically and radiately sulcate and tomentum, and the pore surface is snow white. Phylogenetic analyses based on sequences of the internal transcribed spacer and nuclear large subunit ribosomal DNA confirmed it to be a new species.

• Journal of Species Research
• /
• 제11권3호
• /
• pp.162-168
• /
• 2022

Compared to marine dinoflagellates, freshwater species are rarely recorded in Korea. In the present study, we isolated a freshwater dinoflagellate, Palatinus, from the Paldang Reservoir, Korea, in December 2021. The overall cell shape was ovoid, and the cell size was 34.3 ㎛ in length (25.8-39.5 ㎛) and 28.4 ㎛ in width (21.5-34 ㎛). An eyespot was usually observed near the sulcal region. The Kofoidian plate formula of the species was determined to be 4', 2a, 7", 6c, 5s, 5''', and 2''''. Apical pore complex was not observed. However, variations in the cingular plate caused by the fusion of 3C and 4C were observed. Analyses of 28S rDNA sequences revealed that the unidentified species is 100% similar to Palatinus apiculatus, and clustered together in the same lineage in the phylogenetic tree (100% bootstrap value). Our findings confirmed that the isolated dinoflagellate is Palatinus apiculatus, which was discovered for the first time in Korean freshwaters.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2022년도 봄 학술논문 발표대회
• /
• pp.43-44
• /
• 2022

In this study, the optimum amount of chloride ions is used to collaborate with hybrid corrosion inhibitor for carbon steel rebar treatment in simulated pore concrete (SCP) solution is discovered. The corrosion inhibition performance of hybrid inhibitors is carried on by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PP). The highest corrosion inhibition resistance is found in case of LP-C2 after 240 h exposure. Surface studies including scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to figure out the surface morphology of the steel rebar treated with hybrid inhibitors in order to collaborate well with electrochemical studies. Anodic type inhibition action was confirmed by potentiodynamic polarization study.