• Journal of the Korean Society for Heat Treatment
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• v.29 no.6
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• pp.264-271
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• 2016

The effect of the oxygen content and the annealing temperature on the tensile behavior of the Ti-1.5Al-3Fe-0.25Si-(0.1~0.5)O alloy was investigated. The tensile properties were dependent on the volume fraction of the microstructure constituents, i.e. the equixed ${\alpha}$, equixed ${\beta}$ and lamellar ${\alpha}$. The results showed that the O-partitioned equixed ${\alpha}$ had a much higher strength compared to the equixed ${\beta}$. The strength of the lamellar ${\alpha}$ increased with increasing the annealing temperature because the O content of the lamellar ${\alpha}$ increased. Ti-1.5Al-3Fe-0.25Si-0.3O alloy annealed to $900^{\circ}C$ where the volume fraction of lamellar ${\alpha}$ was the highest exhibited an excellent combination of the strength (1198.5 MPa) and ductility (27.5%). The effect of the lamellar ${\alpha}$ on the ductility was discussed.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.280-289
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• 2013

Various vehicles have been studied in order to protect skin ageing and sustain constantly moisturization. Recently, in relation to maintain of moisture, absorption and penetration of active materials, there has been introducing many preparing methods such as liposome, liquid crystal and multilamellar emulsion. We developed multilayer lamellar vesicle using cetearyl alcohol/ceteth-20 phosphate/dicetyl phosphate as analogy of phospholipid according to variation of shear rate and pH. These multilayer lamellar vesicles were confirmed by cross polarizing microscope. As results, morphologies of lamellar vesicle were not uniformed at low shear rate and pH. Also, stabilities for encapsulation of retinol were observed at $42^{\circ}C$ during two months. As a result, quantitative content of retinol decreased at low pH. Multilayer lamellar vesicle decreased 14% of transepidermal water loss compared with O/W emulsion. We compared multilayer lamellar sun cream to O/W sun cream using in vitro SPF test of water resistance and concluded that multilayer lamellar sun cream is similar to O/W sun cream in water resistance.

• Korean Journal of Materials Research
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• v.10 no.9
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• pp.629-635
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• 2000

The texture evolution during isothermal forging and subsequent heat treatment in Ti-48.5at%Al-0.6at%Mo alloy was investigated. Especially, in the present study, research interest was focused on the interrelation between lamellar volume fraction and textures varied with the change of heat-treated time and temperature. It was found that texture components having ND┴{302) and TD$\perp${100} with minor TD$\perp${111} were developed by isothermal forging. In addition, when the followed heat-treatment time and temperature increased from $1330^{\circ}C$/10h to $1350^{\circ}C$/20h respectively, both the lamellar volume fraction and the intensity of textures mentioned above also gradually increased. However, the tensile elongation at room temperature decreased oppositely, as the lamellar volume fraction increased. These results suggested that tensile properties of $\gamma$-TiAl with the nearly lamellar microstructure at room temperature were affected more strongly by the microstructural features such as lamellar volume fraction rather than by textures.

• Applied Microscopy
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• v.24 no.1
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• pp.77-85
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• 1994

In order to investigating the pulmonary toxicity of the O-chlorobenzyledene malononitrile (CS), lacrimating agent, $2.6g/m^3$ of CS was inhalated to Sprague-Dawley rats in the plastic chamber for 20 minutes. The ultrastructural changes of type II pneumocytes in the lung were observed with Hitachi 600 transmission electron microscope. The results obtained were as follows: 1. 3 hours after exposure to CS the fusion of surface microvilli, dilatation of cristernae of the rough endoplasmic reticulum, atrophy of Golgi complex and condensation, deletion of lamellated membranes in lamellar bodies were observed in type II pneumocytes. 2. One and 2 days after CS-exposure, disorganization of mitochondrial double membranes, fragmentations of rough endoplasmic reticulum were found in the great alveolar cells. In addition, decrease in amount of polyribosome granules and deletion or condensation of lamellated membranes in lamellar bodies were also observed. 3. 4 days after exposure to CS, the type II pneumocyte revealed new whorled lamellar membranes in lamellar bodies, a few intact rough endoplasmic reticulum and restoration of polyribosome granules. It is consequently suggested that CS induces degenerative changes of cytoplasmic organelles in the type II pneumocytes.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.135-140
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• 2000

The characteristics of mechanical behavior were estimated for Ti-6Al-4V alloy with four kinds of microstructure prepared with heat treatments. For this study, impact test, tensile test and fatigue crack growth test were performed, and then compared mechanical properties on the four microstructures. Furthermore, for quantitative evaluation, fractal dimensions of crack pass were obtained using the box counting method. The main results obtained are summarized as follows. (1) The microstructures exhibited equiaxed microstructure, bimodal-microstructure and lamellar microstructure by heat treatment. (2) The impact absorbed energy and elongation is superior in the bimodal-microstructure, and the hardness and tensile strength are superior in the lamellar microstructure. (3) The fatigue crack growth rate is similar to all microstructures in the low ${\Delta}K$ region. The fatigue crack growth rate of equiaxed microstructure is fastest, and that of lamellar microstructure is lowest in the high ${\Delta}K$ region. (4) The fractal dimension D of lamellar microstructure is higher then that of the equiaxed microstructure and bimodal microstructure.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.2
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• pp.281-295
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• 2017

This research is about the reproduction of Baekje's armor-lamellar made for the Hanseong Baekje Museum exhibition. The purpose of the research are as follows. First, to categorize Baekje armor by type based on ancient documents and the excavated relics. Second, to reproduce categorized armor that provide a visual work for use in diverse areas. Baekje armor can be examined through the ancient records and several excavated relics. The results of the research are as follows. First, Baekje armor can be categorized into four types by material: 1) brass 2) iron 3) leather 4) bone. The can also be categorized into three types by finishing a) Hyeongnyubongnyun type (the leather skin interweaves with the lamellar armor method) b) Hyeokpobongnyun type (the method which wraps around the edges of leather skin) c) leather cloth added to clothe type. Second, we reproduced metal armor, iron armor and leather armor using brass, iron and leather (but not bone). Each type of armor were made life-size for exhibition purposes. We used Hyeongnyubongnyun method, Hyeokpobongnyung method and leather cloth; in addition, reproductions were made based on the Yangdang method that connected the front and the back from both sides of the shoulders so it can be open and close at the side part.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.669-677
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• 2016

A miniaturized FTIR spectrometer based on lamellar grating interferometry is being developed for passive remote-sensing. Consisting of a pair of micro-mirror arrays, the lamellar grating can be fabricated using MEMS technology. This paper describes a method to compute the optical field in the interferometer to optimize the design parameters of the lamellar grating FTIR spectrometer. The lower limit of the micro-mirror width in the grating is related to the formation of a Talbot image in the near field and is estimated to be about $100{\mu}m$ for the spectrometer to be used for the wavelength range of $7-14{\mu}m$. In calculating the far field at the detection window, the conventional Fraunhofer equation is inadequate for detection distance of our application, misleading the upper limit of the micro-mirror width to avoid interference from higher order diffractions. Instead, the far field is described by the unperturbed plane-wave combined with the boundary diffraction wave. As a result, the interference from the higher order diffractions turns out to be negligible as the micro-mirror width increases. Therefore, the upper limit of the micro-mirror width does not need to be set. Under this scheme, the interferometer patterns and their FT spectra are successfully generated.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.1021-1030
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• 2007

The effects of the creamide III (CER3) and cholesterol (CHOL) on the structure of a non-hydrous distearoyl phosphatidylcholine (DSPC)-based lamellar liquid crystal (LC) hydrated by only propylene glycol (PG) without water were investigated by differential scanning calorimetry (DSC), X-ray diffractions (XRDs), and polarized microscope (PM). As soon as CER3 was incorporated into the lamellar phase, the characteristic LPP was appeared as well as the characteristic SPP, and the formation of separated CER3 crystalline phase was observed depending upon the increase of CER3 content by XRDs. Also, by DSC, it was shown that the increase of CER3 made the monotectic thermal transition be changed to the eutectic thermal transition which indicates the formation of separated CER3 crystalline phases and the main transition temperatures (Tc1) to be gradually decreased and the enthalpy change (ΔH) to be linearly increased. Incorporating CHOL, the formation of LPP and SPP showed almost similar behaviors to CER3, but incorporating small amounts of CHOL showed the characteristic peaks of CHOL which meant the existence of crystalline CHOL phase due to the immiscibility of CHOL with DSPC swollen by PG differently from CER3, and increasing CHOL made the intensity of the 1st order diffraction for LPP weakened as well as the intensities of the characteristic diffractions for DSPC. Also, in the results of DSC, it showed more complex thermal behaviors having several Tc than CER3 due to its bulky chemical structure. In the present study, the inducement of CER3 and CHOL as other lipids present in human stratum corneum (SC) into a non-hydrous lamellar phase is discussed in terms of the influence on their structural and thermal transition.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.1
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• pp.79-86
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• 2017

This study is related to a lamellar liquid crystal make-up cleansing formulation with a hologram-like unique appearance between two polarizing plates. Make-up cleansing formulations with a lamellar liquid crystal phase have been extensively studied for a long time, but there have been limitations in practical commercialization because of increasing turbidity and viscosity. In this study, to solve this problem, alkyl chains of surfactants were modified to increase the fluidity of the liquid crystal phase, and electrostatic repulsion force was increased by introducing anionic surfactant. The lamellar liquid crystal make-up cleansing formulation which introduced anionic surfactants can easily inhibit crystallization through electrostatic repulsion force, thereby showing excellent stability overtime, maintaining transparent appearance and viscosity. In addition, we have newly introduced an in vitro cleansing evaluation method using fluorescent material and in vivo imaging system (IVIS) for objective and quantitative cleansing ability evaluation. The excellent cleansing ability of lamellar liquid crystal cleansing formulation has been confirmed by newly developed evaluation method. On the other hand, when lamellar liquid crystal make-up cleansing formulation was placed between orthogonally arranged two polarizing plates, a specific pattern like a hologram can be observed. This phenomenon is presumably interpreted as the interference between the visible light passing through the liquid crystal formulation and the lamellar structure. The lamellar structure of cleansing formulation was confirmed by SAXS analysis, exhibiting Bragg spacing ratio of 1 : 2. The lamellar liquid crystal make-up cleansing formulation prepared in this study would be useful for future application in make-up cleansing due to its excellent stability, cleansing ability, and unique hologram-like pattern placed between two polarizing plates.

• Animal cells and systems
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• v.5 no.1
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• pp.17-23
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• 2001

Two new species of oribatid mites, Dicastribates tenuisetosus sp. nov, and Liacarus unjangensis sp. nov. are described from Korea. Dicastribates tenuisetosus sp. nov. is easily distinguishable from a single known species, D. heterotrichus (Mahunka, 1984) from Paraguay by the presence of 14 pairs of distallv attenuate notogastral setae, the smooth rostral and lamellar setae, the relatively short and distally attenuating interlamellar setae, the relatively short sensilli with distinctly clavated head, and presence of two and six setae on epimeral region III and genital plate. Liacarus unjangensis sp. nov. can be easily distinguished from most other known species by the very wide lamellae which cover dorsally whole prodorsum, the presence of equal sized inner and outer teeth of lamellar cusps and the minute rostral, lamellar and interlamellar setae.