• Biomedical Science Letters
• /
• v.10 no.2
• /
• pp.115-120
• /
• 2004

To investigate the correlation between the magnetic resonance imaging (MRI) of cerebral fat embolism that is induced by injecting oleic acid into 10 cats, and a pathologic diagnosis. Using a microcatheter, 30 ${mu}ell$ of oleic acid was injected into the internal carotid artery of 10 cats. MR T2-weighted image (T2WI), diffusion-weighted image (DWI) and Gadolinium-enhanced T1-weighted image (Gd-enhanced T1WI) were obtained after 30 minutes and 2 hours of embolization. After 30 minutes of the embolization, lesions of very high signal intensity were detected by T2WI in 6 cats, and of slightly high signal intensity in 2 cats; in the remaining 2 cats, signal intensity was normal. DWI showed lesions of very high intensity in 9 cats and of slightly high intensity in one cat. According to the findings of light microscopic examination, infarcted lesions mainly involved the gray matter, but also some white matter. A magnetic resonance imaging diagnosis for cerebral fat embolism that was induced by oleic acid through the internal carotid artery in cats showed high signal intensity on the T2WI and the DWI within an initial 2 hours, and with a well enhancement on the Gd-enhanced T1WI. Considering cellular edema, cerebrovascular injury and extracellular space widening, we assumed pathologically that cytotoxic and vasogenic edema exists at the same time.

• Journal of the Korea Computer Graphics Society
• /
• v.18 no.1
• /
• pp.11-21
• /
• 2012

Point-based rendering has gained much attention as an alternative to polygon-based rendering because of its simplicity and flexibility. However, current point-based rendering techniques do not provide a sufficient rendering quality for translucent materials such as human skin. In this paper, we propose a point-based rendering framework with subsurface scattering of light, which is important to create the soft and semi-translucent appearance of human skin. To accurately simulate subsurface scattering in multi-layer materials, we present splat-based diffusion to apply a linear combination of several Gaussian basis functions to each splat in object space. Compared to existing point-based approaches, our method offers a significantly improved visual quality in rendering human faces.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.1
• /
• pp.199-206
• /
• 2005

Mask manufacturing is a high COC and COO process in developing of semiconductor devices because of mask production tool with high resolution. Direct writing has been thought to be the one of the patterning method to cope with development or small-lot production of the device. This study consists two categories. One is the additional process of the direct and maskless patterning generation using SLA for easy and convenient application and the other is a removal process using wet-etching process. In this study, cured status of epoxy pattern is most important parameter because of the beer-lambert law according to the diffusion of UV light. In order to improve the contact force between patterns and substrate, prime process was performed and to remove the semi-cured resin which makes a bad effects to the pattern, spin cleaning process using TPM was also performed. At a removal process, contact force between photo-curable resin as an etching mask and Si wafer is important parameter.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.317-319
• /
• 2007

Recently, there were many researches for efficiency improvement of DSC. Among of these works, research of surface treatment is still a prerequisite for electron diffusion, light-harvesting and surface state of $DSC^{4)}$. Using of the surface treatment, it can be raise up porosity of $TiO_{2}$ nano-crystalline structure on $photo-electrode^{5)}$. There are chemical, physical, electrical and optical methods which raise up its porosity. In this paper, we have designed and manufactured MOPA-type ultrasonic circuit (100W, frequency and duty variable). Manufactured ultrasonic circuit to use to force cavity density and power into $TiO_{2}$ paste. Then, we have optimized forcing time, frequency and duty of ultrasonic irradiation for surface treatment of photo-electrode of DSC. In I-V characteristic test of DSC, ultrasonic and thermal treated DSC shows 19% improved its efficiency against established DSC.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.500-500
• /
• 2013

특정한 유기 물질에 전류를 인가했을 때 발광을 하는 특성을 이용한 Organic Light Emitting Diode (OLED)는 뛰어난 색재현성, 적은 전력소모, 간단한 제조공정, 넓은 시야각 등으로 인해 PDP, LCD, LED에 이은 차세대 디스플레이 소자로 많은 관심을 받고 있다. 하지만 OLED는 각기 다른 굴절률을 가지는 다층구조로 되어있어 실질적으로 소자 밖으로 나오는 빛은 원래 생성된 빛의 20% 정도 밖에 되지 않는다. 이러한 광 손실을 줄이기 위해 Photonic Crystal (PC)이나 마이크로 렌즈 어레이(MLA) 부착 등과 같이 특정한 크기를 갖는 주기적인 나노 구조물을 이용한 광추출 효율 상승 방법은 특정 파장의 빛에서만 효과가 있는 한계가 있었으며 고가의 공정과정을 거쳐야 했으므로 OLED 소자의 가격 향상에 일조하였다. 이의 해결을 위해 본 연구는 유리기판 위에 랜덤한 분포를 가지는 나노 구조물 제작 공정법을 제안한다. 먼저 유리기판 위에 스퍼터로 금속 박막을 입혀 이를 Rapid thermal annealing (RTA) 공정을 이용하여 랜덤한 분포의 Island를 가지는 마스크를 제작하였다. 그 후 플라즈마 식각을 이용하여 유리기판에 나노 구조물을 형성하였고 기판 위에 남아있는 마스크는 Ultrasonic cleaning을 이용하여 제거하였다. 제작된나노구조물은 200~300 nm의 높이와 약 200 nm 폭을 가지고 있다. 제작된 유리기판의 OLED 소자로의 적용가능성을 알아보기 위한 광학특성 조사결과는 300~900 nm의 파장영역에서 맨유리와 거의 비슷한 수직 투과율을 보이면서 최대 50%정도의 Diffusion 비율을 나타내고 있고 임계각(41도) 이상의각도에서 인가된 빛의 투과율에 대해서도 향상된 결과를 보여주고 있다. 제안된 공정의 전체과정 기존의 PC, MLA 등의 공정에 비해 난이도가 쉽고 저가로 진행이 가능하며 추후 OLED 소자에 적용될 시 대량생산에 적합한 후보로 보고 있다.

• Textile Coloration and Finishing
• /
• v.17 no.2 s.81
• /
• pp.1-9
• /
• 2005

Mixed dyeing were carried out ll"ing yellow, red and purple loess as mineral dyes verify their dyeability, color shade and fastness. The proper density of Chinese ink were 0.5, 1.0, 2.0, 2.5, $5\%$(o.w.b). The grinded chinese ink had better stainability compared with the general Chinese ink. The mixed dyeing improvement of stainability in the density of loess of $40\%$(o.w.b) among the yellow, red, and purple loess. The colors in the mixed dyeing with Chinese ink were $3.801\~8.13Y,\;0.128\~7.038Y\;and\;4.222\~9.304Y$. The colorfastness were 1-2 in the homogeneous dyeing with Chinese ink. It was improved 1-3 in the mixed dyeing. Light colorfastness of the homogeneous and mixed dyeing were excellent as a value of 5. The dry rubbing fastness in the homogeneous dyeing was 3-3.5, and 3 in the wet rubbing. As for the mixed dyeing, the dyes of Chinese ink showed poor diffusion into the fiber, resulting in low fastness due to the existence of the dyes on the surface.

• Journal of Pharmaceutical Investigation
• /
• v.35 no.3
• /
• pp.207-224
• /
• 2005

The objective of this study was to explore the principles of SUPAC-SS and its regulatory application in handling postapproval changes to nonsterile semisolid dosage forms. The types of postapproval changes that SUPAC-SS described were modifications in formulation (components and composition), batch size, manufacturing equipment & process, and the site of manufacturing. SUPAC-SS defined the levels of postapproval changes and what chemistry, manufacturing, and control tests should be conducted for each change level. The guidance also specified several occasions the manufacturers should perform in vitro release test (Franz cell diffusion test) and/or in vivo bioequivalence test. Finally, SUPAC-SS classified appropriate filing forms to be used in supporting postapproval changes. It was crystal clear that SUPAC-SS helped maintain the safety and quality of approved semisolid dosage forms when they were subject to certain postapproval changes. The availability of SUPAC-SS made contributions to reducing regulatory burdens of the industry, as well as expediting the postapproval process of regulatory agencies. This study also shed light on the background of relevant pharmaceutical sciences that the SUPAC-SS guidance adopted. Finally, the KFDA and the industry were strongly urged to implant a similar guidance in handling postapproval changes to semisolid dosage forms available in the Korean marketplace.

• Journal of Pharmaceutical Investigation
• /
• v.35 no.1
• /
• pp.7-16
• /
• 2005

Gardeniae Fructus is consisted of geniposide and it's derivatives. For the purpose of treatment of skin disease, geniposide and hydrolyzed products (HP) of Gardeniae Fructus were studied on skin permeation and cross1inking with biological tissue. The hydrolyzed products (HP) and active ingredients of Gardeniae Fructus were identified and investigated about skin permeability. Genipin has provided low cytotoxic cross1inking reagents and formed stable and biocompatible crosslinked products. The permeation enhancing effects of geniposide and genipin under the hydrolyzed products of cream and hydrogel preparations were tested using Franz type diffusion cell and the skin of hairless mouse. The remaining proportions of geniposide and genipin were measured in the hydrolyzed products of cream and hydrogel preparations. The crosslinking of epidermic and endodermic tissue with genipin under the hydrolyzed prodcuts of cream and hydrogel preparation was observed using light microscopy. Increased absorption ratio of the skin of hairless mouse about genipin was higher than that of geniposide. Loads at break, tensile strengths and skin permeation rate of the hydrolyzed products (HP) of cream and hydrogel preparations were higher than the nonhydrolyzed products (NHP). The hydrolyzed products (HP) of cream and hydrogel of Gardeniae Fructus Extracts were proper preparations and crosslinking agents to increase the transdermal absorption with epidermic and endodermic tissue.

• Proceedings of the KOSOMBE Conference
• /
• v.1997 no.05
• /
• pp.379-382
• /
• 1997

A method for measuring optical properties of biological medium was investigated by using the frequency domain spectroscopy. When amplitude-modulated light with the frequency of several tens up to several hundred MHz propagates through a scattering medium, the phase lag and the amplitude reduction occur. The phase lag depends on the average of optical path lengths. The amplitude reduction with respect to the radial distance is influenced by the penetration depth. The mean of optical path length and penetration depth are related to optical coefficients. The phase lag and the amplitude reduction were measured based on the heterodyne detection method. The experimental data were fitted with the theoretical curves derived from diffusion theory and the absorption and scattering coefficients were calculated.

• Polymer(Korea)
• /
• v.37 no.3
• /
• pp.294-301
• /
• 2013

Polymersomes made of biodegradable triblock copolymers based on poly(fumaric acid-co-sebacoyl chloride)/PEG (PEG-co-P(FA/SC)-co-PEG) were prepared and studied in aqueous solutions. TEM confirmed the formation of vesicles in aqueous media. Aggregation behavior of the copolymers was studied by fluorescence spectroscopy of 8-anilino-1-naphthalenesulfonic acid, and the critical aggregation concentration (c.a.c.) of the copolymer was found to be ${\sim}26.2{\mu}M$ indicating desirable stability of the vesicles. Dynamic light scattering revealed that the size of the vesicles was distributed within the range of 170-270 nm. Turbidity measurements confirmed the relative short-term stability of the polymersomes. Carboxyfluorescein, a hydrophilic compound, was simply encapsulated in the vesicles during polymersome preparation. The release of encapsulant from the polymersomes at 25 and $37^{\circ}C$ lasted about 3 weeks, and the rate of release followed a first-order kinetics. The release is speculated to be primarily carried out through diffusion. These results confirm that these polymersomes are promising as controlled-release carriers of various drugs.