• Journal of Advanced Marine Engineering and Technology
• /
• v.18 no.2
• /
• pp.54-63
• /
• 1994

Mg thin films were prepared on SPCC(cold-rolled steel) substrates by vasuum evapoaration and ion-plating. The influence of argon gas pressure and substrates bias voltage on the crystal orientation and morphology of the film was determined by using X-ray diffraction and scanning electron micrography (SEM), respectively. And the effect of crystal orientation and morphology of the Mg thin films on corrosion behavior was estimated by measuring the anodic polarization curves in deaerated 3% NaCl solution. The crystal orientation of the Mg films deposited at high argon gas pressure exhibited a (002) preferred orientation, regardless of the substrate bias voltage. Film morphology changed from a columnar to a granular structure with the increase of argon gas pressure. The morphology of the films depended not only on argon gas pressure but also bias voltage ; i.e., the effect of increasing bias voltage was similar to that of decreasing argon gas pressure. The influences of argon gas pressure and bias voltage were explained by applying the adsorption inhibitor theory and the sputter theory. And also, this showed that the corrosion resistance of the Mg thin films can be changed by controlling the crystal orientaton and morphology.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.6
• /
• pp.1829-1833
• /
• 2012

Titania spheres were synthesized using binary ionic liquids to examine the electrocatalytic activity in acid solution. The morphology of $TiO_2$ particles was significantly different with the composition of ionic liquids. Among the binary ionic liquids, four set of mixtures led to the formation of $TiO_2$ sphere with various sizes. The morphology and structure of $TiO_2$ particles were characterized by XRD, $N_2$ physisoption and SEM analysis. All samples possessed an anatase phase after calcinations at $500^{\circ}C$. The structural properties of the samples were varied significantly with the morphology. In cyclic voltammograms, the morphology of $TiO_2$ spheres affected the electrocatalytic activity in water electrolysis. Among the samples, [Omim][$BF_4$]+[Hmim][$BF_4$] was the most effective ionic liquid to synthesize $TiO_2$ sphere with optimum morphology showing the highest electocatalytic performance.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.11a
• /
• pp.368-369
• /
• 2003

각종 배출원에서 배출된 입자상 물질은 대기 중 확산, 이동, 침착 등을 통해 국지적 도시오염 뿐만 아니라 장거리까지도 이동함으로서 광역적 대기오염의 원인이 되고 있는 등 입자상 물질의 발생원 추적에 관한 연구가 필요한 실정이다. 지금까지 입자상 물질의 발생원 추적은 대부분 배출원의 발생량 조사나 필터에 포집된 시료의 전체적인 화학적 분석의 개념으로 단시간의 시간변동과 개개의 입자가 가지는 정보가 무시되고 평균화되고 있다. (중략)

• Applied Microscopy
• /
• v.50
• /
• pp.10.1-10.6
• /
• 2020

Plant specimens for scanning electron microscopy (SEM) are commonly treated using standard protocols. Conventional fixatives consist of toxic chemicals such as glutaraldehyde, paraformaldehyde, and osmium tetroxide. In 1996, methanol fixation was reported as a rapid alternative to the standard protocols. If specimens are immersed in methanol for 30 s or longer and critical-point dried, they appear to be comparable in preservation quality to those treated with the chemical fixatives. A modified version that consists of methanol fixation and ethanol dehydration was effective at preserving the tissue morphology and dimensions. These solvent-based fixation and dehydration protocols are regarded as rapid and simple alternatives to standard protocols for SEM of plants.

• Korean Journal of Materials Research
• /
• v.9 no.12
• /
• pp.1245-1251
• /
• 1999

Phase-change optical disk very rapid recording, high densification of data, resulting in high feedback rate and good C/N(carrier to noise) ratio of a feedback signal. However, repetitive thermal energy may cause the deformation of a disk or the lowering of an eliminability and a cyclability of the recording. The lowering of the cyclability can be reduced by insertion of thin layer of ZnS-$SiO_2$ dielectric thin film in appropriate disk structure between the upper and lower part of the recording film. Using the Taguchi method, optimum conditions satisfying both the optimized quality characteristic values and the scattering values for film formation were found to be the target R.F. power of 200W, the substrate R.F. power of 20W, the Ar pressure of 6mTorr, and the electrode distance of 6cm. From the refractive index data, the existence of the strong interaction between the electrode distance and Ar pressure was confirmed, and so was the large effect of the electrode distance on transmittance. According to the analysis of TEM and XRD, the closer the electrode distance was, the finer was the grain size due to the high deposition rate. However, the closer electrode distance brought the negative effect on the morphology of the film and caused the reduction of transmittance. AFM and SEM analyses showed that the closer the electrode distance was, the worse was the morphology due to the high rate of the deposition. Under optimum condition, the deposited thin film showed a good morphology and dense microstructure with less defects.

• Journal of the Mineralogical Society of Korea
• /
• v.28 no.2
• /
• pp.195-207
• /
• 2015

Physical properties of strontianite ($SrCO_3$) synthesized under variable conditions such as different ionic strength, temperature, and aging time were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). All synthesized samples show a single phase of strontianite. Crystallinity of the synthesized strontianite increases with increasing temperature and ionic strength with $NaNO_3$. Crystal sizes of the samples increase dramatically, and their morphology changes from rod or dendritic to prismatic shape as ionic strength and temperature of the solution increase. In addition, crystal sizes increase, and their morphology changes from rod or prismatic crystals to spheroidal aggregates with increasing aging time. These results suggest that changes in conditions of the synthesis for strontianite play an important role in controlling the crystallinity and morphology of results provide crucial information on the prediction for the physical properties of strontianite under different conditions during the formation of strontianite crystals.

• Membrane Journal
• /
• v.22 no.4
• /
• pp.258-264
• /
• 2012

In this study, to research effect of coagulation bath and composition of dope solution, polysulfone flat sheet membrane was fabricated by phase inversion method. PEG and PVP were used as additive. Concentration of polymer and additive, composition of coagulation bath was controlled to prepare flat sheet membrane. And then the morphology and water flux of prepared membrane were measured by FE-SEM and water flux testing apparatus. The highest value of water flux was measured at the membrane prepared under a 15 wt% PSF, 25 wt% PEG conditions, and water as coagulation bath. The pure water flux of the membrane composed of PSf/PEG was drastically decreased with increasing amount of DMAc. We confirmed that change of amount in additive and composition in coagulation bath influence the morphology and water flux performance of the membrane.

• Parasites, Hosts and Diseases
• /
• v.54 no.6
• /
• pp.777-786
• /
• 2016

Raillietina species are prevalent in domestic chickens (Gallus gallus domesticus) in Phayao province, northern Thailand. Their infection may cause disease and death, which affects the public health and economic situation in chicken farms. The identification of Raillietina has been based on morphology and molecular analysis. In this study, morphological observations using light (LM) and scanning electron microscopies (SEM) coupled with molecular analysis of the internal transcribed spacer 2 (ITS2) region and the nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) gene were employed for precise identification and phylogenetic relationship studies of Raillietina spp. Four Raillietina species, including R. echinobothrida, R. tetragona, R. cesticillus, and Raillietina sp., were recovered in domestic chickens from 4 districts in Phayao province, Thailand. LM and SEM observations revealed differences in the morphology of the scolex, position of the genital pore, number of eggs per egg capsule, and rostellar opening surface structures in all 4 species. Phylogenetic relationships were found among the phylogenetic trees obtained by the maximum likelihood and distance-based neighbor-joining methods. ITS2 and ND1 sequence data recorded from Raillietina sp. appeared to be monophyletic. The query sequences of R. echinobothrida, R. tetragona, R. cesticillus, and Raillietina sp. were separated according to the different morphological characters. This study confirmed that morphological studies combined with molecular analyses can differentiate related species within the genus Raillietina in Thailand.

• Rapid Communication in Photoscience
• /
• v.1 no.1
• /
• pp.11-12
• /
• 2012

The naphthalic amide derivatives were synthesized by simple condensation and were crystallized by acetonitrile solution. The SEM images of products with methyl group and nitro group, respectively, showed rod shape while the SEM images of products with other groups ($N(CH_3)_2$, $OCH_3$, H, F, and Cl), respectively, showed plate shape. We were known from these results that the substituent of ending group played an important role in the crystallization of single molecule and the morphology of naphthalic derivatives could be controlled by only change of ending group in single molecule.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2003.04a
• /
• pp.151-159
• /
• 2003

This study presents method for self-calibration of the SEM(Scanning Electron Microscope) stereo image using the standard microprobe with same grid pattern and using parallel and central perspective projection equation. Result showed that parallel projection method is more suitable for standard microprobe. The maximum error of 3D coordinates acquired by this method did not exceed 5 $\mu\textrm{m}$, and DSM(Digital Surface Model) for three dimensional measurement of the rock sample was generated by the digital photogrammetry. This result can be used for quantification of micro scale change of shape and analysis of the micro morphology of rock due to weathering.