• Journal of Microbiology and Biotechnology
• /
• v.15 no.2
• /
• pp.425-427
• /
• 2005

The steam distillate obtained from Thujopsis dolabrata var. hondai sawdust was fractionated by centrifugal thin-film evaporation, and the fractions were then investigated for antiplatelet activity using washed rabbit platelets. The biologically active constituent of T. dolabrata var. hondai sawdust was isolated by silica gel column and HPLC chromatographies and characterized as carvacrol by various spectral analyses. Carvacrol inhibited platelet aggregation induced by collagen, arachidonic acid, and platelet activating factor with IC$_{50}$ values of 12.6, 2.5, and 385.3 $\mu$M, respectively. However, carvacrol had no effect on thrombin, calcium ionophore A23l87, or phorbol l2-myristate l3-acetate induced platelet aggregation. Carvacrol was a much more potent inhibitor, as antiplatelet agents, compared with aspirin. These results suggest that carvacrol isolated from T. dolabrata var. hondai sawdust may be useful as a lead compound for inhibiting arachidonic acid-induced platelet aggregation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.25 no.12
• /
• pp.674-678
• /
• 2013

We present a non-invasive technique to the measure temperature distribution in nano-sized porous thin films by means of the two-color laser-induced fluorescence (2-LIF) of rhodamine B. The fluorescence induced by the green line of a mercury lamp with the makeup of optical filters was measured on two separate color bands. They can be selected for their strong difference in the temperature sensitivity of the fluorescence quantum yield. This technique allows for absolute temperature measurements by determining the relative intensities on two adequate spectral bands of the same dye. To measure temperature fields, Silica (SiO2) nanoporous structure with 1-um thickness was constructed on a cover glass, and fluorescent dye was absorbed into these porous thin films. The calibration curves of the fluorescence intensity versus temperature were measured in a temperature range of $10-60^{\circ}C$, and visualization and measurement of the temperature field were performed by taking the intensity distributions from the specimen for the temperature field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.119-120
• /
• 2008

ILD CMP process has been well accepted for the planarization of the dielectric oxide film and becomes a critical process in ULSI manufacturing due to the rapid shrinkage of the design rule for the device. In total manufacturing process steps for a device, the proportion of ILD CMP process has been gradually increased. Ever since ILD CMP has been introduced, the scratches have been a major defects on polished surfaces which cause the electrical shorts between vias or metal lines [1,2]. It was reported that micro-scratches are caused by large, irregularly shaped particles during CMP process. Therefore, most of the CMP users have used < 5 m POU filter to remove and reduce the scratch source from the slurry. However, the scratch has always been the biggest concern in ILD polishing whatever preventive actions are taken. Silica and ceria slurries are widely used for ILD CMP process. There are not much differences in generated scratches and their formation mechanism. In this study, the scratches were investigated as a function of polishing conditions with possible explanation on formation mechanism in ILD CMP.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.389-392
• /
• 2009

Metal oxides have been proposed as an alternative channel material to hydrogenated amorphous silicon in thin film transistors (TFTs) because their higher mobility and stability make them suitable for transistor active layers. Thin films of indium zinc oxide (IZO) were deposited using a High Target Utilization Sputtering (HiTUS) system on various dielectrics, some of which were also deposited with the HiTUS. Investigations into bottom-gated IZO TFTs have found mobilities of 8 $cm^2V\;^1s^{-1}$ and switching ratios of $10^6$. There is a variation in the threshold voltage dependent on both oxygen concentration, and dielectric choice. Silica, alumina and silicon nitride produced stable TFTs, whilst hafnia was found to break down as a result of the IZO.

• Membrane Journal
• /
• v.26 no.5
• /
• pp.351-364
• /
• 2016

In recent decades, many researchers have tried to improve desalination performances of polyamide (PA) thin-film composite membranes (TFCs) by incorporating nanomaterials into a selective PA layer. This review focuses on PA-based nanocomposite membranes with high performances for energy-effective desalination in reverse osmosis. Carbon based nanomaterial (e.g., graphene oxide (GO), carbon nanotubes (CNT)) and/or other nanoparticles (e.g., zeolite, silica and etc.,) were applied to overcome the trade-off correlation between water permeability and salt rejection of current polymeric desalination membranes. Here, this brief review will discuss current studies of PA-based nanocomposite membranes with enhanced separation characteristics and provide the future research direction to achieve further improved desalination performances.

• Proceedings of the KIEE Conference
• /
• 2005.07c
• /
• pp.1930-1932
• /
• 2005

Colloidal Silica(CS)/methyltrimethoxy silane(MTMS) and CS/MTMS/epoxy silane(Es) sol solutions were prepared in variation with synthesizing parameters such as kinds of CS, kinds of silane and reaction time. In order to understand its physical and chemical properties, sol-gel coating films on glass were fabricated. In the case of CS/MTMS sol, the coating films had high contact angle and more enhanced flat surface than those in the case of CS/MTMS/ES sol. Also, the coating films obtained from single CS had a better flat surface than those obtained from mixed CS. In the case of thermal stability, thermal dissociation of CS/MTMS and CS/MTMS/ES sol-gel coating films did not occur up to $550^{\circ}C$ and $440^{\circ}C$ respectively. The thickness of coating films obtained from CS/MTMS sol increased than those of CS/MTMS/ES sol. In addition, the coating films obtained from single CS were more thicker than those obtained from mixed CS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.42-43
• /
• 2005

본 연구에서는 Cu 슬러리에 부식방지제인 BTA를 첨가하여 슬러리내의 과수의 농도, pH 의 변화, 연마입자의 종류에 따라 연마거동에 미치는 영향과 각 chemical 변화에 따른 Cu surface의 변화를 살펴보았다. BTA (Benzotriazole, $C_6H_4C_3H$)를 첨가함으로써 본 연구에서 시행된 pH 와 과수의 변화에 상관없이 Cu-BTA film을 형성하여 Cu의 dissolution을 최대한 억제하는 것을 확인할 수 있었다. 또 그로인해 BTA를 첨가하지 않았을 때보다 얇은 passivation layer를 형성함을 알 수 있었고 contact angle도 더 높았다. 연마율의 경우에도 BTA가 첨가됨으로써 감소됨을 확인할 수 있었고 연마입자로 alumina particle을 사용한 경우에는 pH6, 과수 10vol%이상에서는 오히려 연마율이 증가하였다. fumed silica의 경우에는 hardness가 작아 mechanical적인 제거력이 낮아 BTA가 첨가되어도 연마율에는 큰 영향이 없었다.

• Journal of the Optical Society of Korea
• /
• v.17 no.1
• /
• pp.1-4
• /
• 2013

For the conventionally polished fused silica substrate, an around 100 nm depth redeposition polishing layer was formed on the top of surface. Polishing compounds, densely embedded in the redeposition polishing layer were the dominant factor that limited the laser induced damage threshold (LIDT) of transmission elements in nanosecond laser systems. Chemical etching, super-precise polishing and ion beam etching were employed in different ways to eliminate these absorbers from the substrate. After that, Antireflection (AR) coatings were deposited on these substrates in the same batch and then tested by 1064 nm nano-pulse laser. It was found that among these techniques only the ion beam etching method, which can effectively remove the polishing compound and did not induce extra absorbers during the disposal process, can successfully improve the LIDT of AR coatings.

• Korean Journal of Metals and Materials
• /
• v.46 no.7
• /
• pp.464-470
• /
• 2008

Metallic nanostructures have great potential for bio-chemical sensor applications due to the excitation of localized surface plasmon and its sensitive response to environmental change. Unlike the commonly explored absorption-based sensing, the optical scattering provides single particle detection scheme. For the localized surface plasmon resonance spectroscopy, the metallic nanostructures with controlled shape and size have been usually fabricated on adhesion-layer pre-coated transparent glass substrates. In this study, we calculated the optical scattering properties of plasmonic Au nanodisc using a discrete dipole approximation method and analyzed the effect of adhesion layer on them. Our result also indicates that there is a trade-off between the surface plasmon damping and the capability of supporting nanostructures in determining the optimal thickness of adhesion layer. Marginal thickness of Ti adhesion layer for supporting Au nanostructures fabricated on a silica glass substrate was experimentally analyzed by an adhesion strength test using a nano-indentation technique.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.44 no.3
• /
• pp.211-218
• /
• 2018

Instant face lifting cosmetics contain various film forming agents for stretching the wrinkles on the skin surface. But, most of the film-forming polymers have sticky feels. And they are easily scrubbed out when skin is rubbed on. In this study, we focused on the influence of sodium silicate that has rapid film forming effect on skin surface and immediate wrinkle reducing effect. Sodium silicate, also known as water glass or soluble glass, is a compound containing sodium oxide and silica. Sodium silicate is a white powder that is readily soluble in water, producing an alkaline solution. Sodium silicate is stable in neutral and alkaline solutions. The sodium silicate solution hardens by drying in air and rapidly forms a thin film. When the solution is applied to the skin, the fine membrane coating is formed by water evaporation and ionic bond re-formation. It also makes the strong siloxane (Si-O) bonding on the skin surface. When these fixation properties are applied to cosmetics, they can give remarkable skin tightening effect. The sodium silicate solution can provide the lifting effect by forming a film on skin at a proper concentration. But, skin irritation may be caused with too high concentration of sodium silicate. We studied a desirable range of the sodium silicate concentration and combination with other fixatives for skin care formulation that has no sticky feels and no scrubbing out phenomenon. Immediate lifting gel was developed by using sodium silicate and various thickening systems. Among of the various thickeners, aluminum magnesium silicate showed the best compatibility with sodium silicate for rapid lifting effect. This instant physical lifting gel was confirmed as a low stimulating formula by skin clinical test.