• Applied Microscopy
• /
• v.46 no.4
• /
• pp.238-243
• /
• 2016

Twinning-induced plasticity (TWIP) steels with the austenite structure containing high manganese exhibit both good strength and excellent formability. Such properties originate from crystallographic slip and mechanical twins produced when the austenite structure is under mechanical stress. There are 12 twin systems, referred to as twin variants, when slip is induced. These twin systems include twin planes and twin directions and play an important role in determining strength and ductility of the material by strongly influencing texture formation of the austenite structure. In the present study, twins produced in a high-Mn TWIP steel as a result of uniaxial tension were observed using a transmission electron microscope; a comparative analysis was performed through interaction energy calculations. Electron diffraction was used to determine the twin system with respect to the uniaxial tension direction in each grain. Both the Schmid factors and interacting energies required for the generation of twins were calculated and subsequently compared with experimental results. This approach demonstrated the possibility of predicting the deformation behavior of the material.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.4
• /
• pp.84-91
• /
• 2005

We measured the pitch of one-dimensional (ID) grating specimens using a metrological atomic force microscope (M-AFM). The ID grating specimens a.e often used as a magnification standard in nano-metrology, such as scanning probe microscopy (SPM) and scanning electron microscopy (SEM). Thus, we need to certify the pitch of grating specimens fur the meter-traceability in nano-metrology. To this end, an M-AFM was setup at KRISS. The M-AFM consists of a commercial AFM head module, a two-axis flexure hinge type nanoscanner with built-in capacitive sensors, and a two-axis heterodyne interferometer to establish the meter-traceability directly. Two kinds of ID grating specimens, each with the nominal pitch of 288 nm and 700 nm, were measured. The uncertainty in pitch measurement was evaluated according to Guide to the Expression of Uncertainty in Measurement. The pitch was calculated from 9 line scan profiles obtained at different positions with 100 ㎛ scan range. The expanded uncertainties (k = 2) in pitch measurement were 0.10 nm and 0.30 nm for the specimens with the nominal pitch of 288 nm and 700 nm. The measured pitch values were compared with those obtained using an optical diffractometer, and agreed within the range of the expanded uncertainty of pitch measurement. We also discussed the effect of averaging in the measurement of mean pitch using M-AFM and main components of uncertainty.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.36 no.1
• /
• pp.16-22
• /
• 2010

Purpose: The purpose of this study was not only to evaluate the relative mRNA expression of interleukin-$1{\beta}$(IL-$1{\beta}$), cyclooxygenase2 (COX-2) and prostaglandin E2 (PGE2) by RT-PCR analysis but to observe pattern of edema by light microscopic and electron microscope after topical apply of hyaluronic acid in inflammation-guided mouse. Material and methods: Mice of this study were devided into 4 groups: Control group (no inflammation guided), Positive control (inflammation guided + vaselin apply), Protopic group (inflammation guided + protopic apply), Hyaluronic group (inflammation guided + hyaluronic acid apply). Results: Hyaluronic group showed less expressions of IL-$1{\beta}$, COX-2, PGE2 than those of positive control & protopic group. Hyaluronic group revealed a decreased inflammation than positive control & protopic group in Light Microscope. Hyaluronic group appeared decreased edema of ear compare to positive control & protopic group in Elecron Microscope. Conclusion: It was considered that hyaluronic acid has an antiinflammatory effect for intercepting the gene expression of cytokines related to inflammation.

• Korean Journal of Materials Research
• /
• v.19 no.3
• /
• pp.151-155
• /
• 2009

Micro-scale copper bumps for build-up PCB were electroplated using a pulse-reverse method. The effects of the current density, pulse-reverse ratio and brightener concentration of the electroplating process were investigated and optimized for suitable performance. The electroplated micro-bumps were characterized using various analytical tools, including an optical microscope, a scanning electron microscope and an atomic force microscope. Surface analysis results showed that the electroplating uniformity was viable in a current density range of 1.4-3.0 A/$dm^2$ at a pulse-reverse ratio of 1. To investigate the brightener concentration on the electroplating properties, the current density value was fixed at 3.0 A/$dm^2$ as a dense microstructure was achieved at this current density. The brightener concentration was varied from 0.05 to 0.3 ml/L to study the effect of the concentration. The optimum concentration for micro-bump electroplating was found to be 0.05 ml/L based on the examination of the electroplating properties of the bump shape, roughness and grain size.

• Applied Microscopy
• /
• v.36 no.2
• /
• pp.47-55
• /
• 2006

In this paper a transmission electron microscope (TEM) observation of fine Cu precipitates distributed randomly in Al-2.5Cu-1.5Mg wt.% alloy is first reported. This new observation happened to occur when an ion milling was peformed to remove oxides on the specimen, particularly, aged 100 hours at $150^{\circ}C$. Meanwhile the oxides were identified to be $Cu_2O$ particles. For this work involved with analysis of diffraction rings, the formulation of the electron diffraction rings pattern for powder particles was made. Finally the significance of this unexpected ion milling effort on the alloy was discussed

• Journal of Sericultural and Entomological Science
• /
• v.33 no.1
• /
• pp.21-26
• /
• 1991

Bombyx mori nuclear polyhedrosis virus (BmNPV) was successfully multiplied in the nuclear of BmN4 cells cultured with insect Grace's medium. By electron microscopic observation, the virons had a single nucleocapsid in an envelope. Polyhedral protein synthesis of BmNPV in BmN4 cells was detected at 18 hr p.i. and polyhedral protein was a singlepolypeptide with a M.W of 30 kd. At 48 hr p.i. polyhedra formation was observed by inverted mociroscope and electron microscope. Genome analysis of BmNPV by restriction endonucleases was not revealed the difference between virus produced in vivo and that in vitro.

• Journal of Powder Materials
• /
• v.23 no.1
• /
• pp.15-20
• /
• 2016

Niobium is one of the most important and rarest metals, and is used in the electronic and energy industries. However, it's extremely high melting point and oxygen affinity limits the manufacture of Nb coating materials. Here, a Nb coating material is manufactured using a kinetic spray process followed by hot isotactic pressing to improve its properties. OM (optical microscope), XRD (X-ray diffraction), SEM (scanning electron microscopy), and Vickers hardness and EPMA (electron probe micro analyzer) tests are employed to investigate the macroscopic properties of the manufactured Nb materials. The powder used to manufacture the material has angular-shaped particles with an average particle size of $23.8{\mu}m$. The porosity and hardness of the manufactured Nb material are 0.18% and 221 Hv, respectively. Additional HIP is applied to the manufactured Nb material for 4 h under an Ar atmosphere after which the porosity decreases to 0.08% and the hardness increases to 253 Hv. Phase analysis after the HIP shows the presence of only pure Nb. The study also discusses the possibility of using the manufactured Nb material as a sputtering target.

• Food Science of Animal Resources
• /
• v.30 no.4
• /
• pp.551-559
• /
• 2010

Among the food constituents, proteins differ in coagulation properties as compared to other constituents in food system. Especially milk protein coagulate through different pathways thus this coagulability can be used for manufacture of various dairy products or as a determinant of dairy product analysis. These milk coagulation methods include organic solvent, isoelectric point, trichloroacetic acid, Ca-sensitive casein, heavy metal ion and rennet coagulation. The coagulation experiment was performed using above parameters at $0^{\circ}C$ and $25^{\circ}C$ to find the dehydration conditions before coagulating for precheese powder making. After different chemical treatments, there was no coagulation at $0^{\circ}C$ rather at $25^{\circ}C$ whatever the mode of coagulation methods was. The appearance of precipitate with coagulation methods was quite different from above mentioned methods of coagulation illustrated by scanning electron microscope. These powders were used for fabrication of camembert cheese by renneting coagulation at $0^{\circ}C$, showing the possibility of cheese materials and of food additives for fabrication of products.

• Journal of the Korean Electrochemical Society
• /
• v.5 no.2
• /
• pp.43-46
• /
• 2002

Commercial titanium rod was anodized in three types of electrolytes such as 0.06 mol/L $\beta-glycerophosphate+0.3mol/L$ calcium acetate, 0.06mol/L $\beta-glycerophosphate+0.3mol/L$ sodium acetate and 0.06 mol/L $\beta-glycerophosphate+5mol/L$ calcium phosphate. The titanium oxide layer $(TiO_2)$ was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and electron spectroscopy chemical analysis (ESCA). Numerous micropores were observed on the titanium oxide layer by SEM. The diameter of micropores increased with the increase of electrolytic voltage. The titanium oxide layer was composed of anatase structure. The phosphorous element was detected at 130 eV binding energy, but calcium was not found in the oxide layer because of lower contents. After anodizing the oxide layer was etched in the 30g/L NaOH solution at $80^{\circ}C$ for 1hr. The surroundings of micropores were much more smoothed and rounded than before alkaline etching.

• Textile Coloration and Finishing
• /
• v.9 no.2
• /
• pp.1-9
• /
• 1997

This paper was carried out to introduce flame retardant and antibiotic properties to polyester(PET) and polyester/cotton(P/C) blend fabrics. PET and P/C blend fabrics were treated by a paddry-cure method in the aqueous solutions of the finishing agents(JA 6034, JA 6050, DC-5700). The corona discharge technique was applied to increase the polar group of the polymer surface. The characteristics of the treated fabric were investigated by means of scanning electron microscope (SEM) and electron spectroscopy for chemical analysis(ESCA), and water penetration time, limiting Oxygen index(LOI), and K/S value were also measured. Wettability of the fabrics was increased considerably with the corona discharge treatment. ESCA was used to elucidate the surface chemical composition of the fabrics treated with the corona discharge. Relative Ols intensity increased and oxygen was incorporated in the form of -C-O-, -C=O, and O=C-O on the polymer surface. The current study indicated that corona discharge treatment was effective for modifying the polymer surface.