• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.9
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• pp.754-760
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• 2008

A two-photon induced photoreduction process suggests a possibility for fabricating complicated metallic microstructures which can be applied to 3-D micro-circuits and optical devices, etc. The process employs the photoreduction of silver ions in a metallic solution which is composed of metallic salt ($AgNO_3$) and watersoluble polymer ((poly(4-styrenesulfonique acid) 18wt. % in $H_2O$, $(C_8H_8O_3S)_n$)). In this process, the improvement of the resolution and the uniformity of fabricated metallic structures are important issues. To address these problems, continuous forming window (CFW) is obtained from a parametric study on the conditions of laser power and scanning velocity and the direct seed generation (DSG) method is proposed. Silver nano particles are uniformly generated in a metallic solution through the DSG method, which enables the decrease of a laser power to trigger the photoreduction of silver ions as well as the increase of metal contents in a metallic solution. So the two-photon induced photoreduction property of a metallic solution is improved. Through this work, precise silver patterns are fabricated with a minimum line width of 400 nm.

• Korean Journal of Optics and Photonics
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• v.21 no.2
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• pp.61-68
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• 2010

Optical simulation methods were applied to the edge-lit LED backlight for LCD TV applications in order to optimize the optical structure of the light guide plate(LGP), and thus to improve the uniformity properties by removing the bright spots caused by LED's. The edge-lit LED backlight consisted of three white LED's with a lamp cover, a light guide plate, and a reflection film. When there was no pattern on the entrance side surface of the LGP, the illuminance uniformity was sensitively dependent on the distance d between the LED and the entrance surface. The illuminance uniformity increased with d but its increasing rate slowed down when d was beyond ~ 1.5 mm. When micro-patterns such as a lenticular lens array (LLA) or a serration pattern were formed on the entrance surface, the illuminance uniformity was improved substantially even for the case of very small d. At the same simulation condition, the lightguide with serration pattern showed a better uniformity than that with LLA pattern. Additional improvement could be achieved by changing the refractive index of the micro-patterns. These results suggest that using micro-patterns is a very effective way to reduce the bright spots due to their refracting function for the concentrated incident rays onto the LGP.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.227-235
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• 2000

Agricultural products are easily deformable its shape because of some external forces. However, these force behavior is difficult to measure quantitatively. Until now, many researches on the mechanical property was performed with various methods such as material testing, chemical analysis and non-destructive methods. In order to investigate force behavior on the cellular unit of agricultural products, electro-microscope based 3D image processing method will contribute to analysis of plant cells behavior. Before image measurement of plant cells, plant sample was cut off cross-sectioned area in a size of almost 300-400 ${\mu}$ m units using the micron thickness device, and some of preprocessing procedure was performed with fixing and dyeing. However, the wall structure of plant cell is closely neighbor each other, it is necessary to separate its boundary pixel. Therefore, image merging and shrinking algorithm was adopted to avoid disconnection. After then, boundary pixel was traced through thinning algorithm. Each image from the electro-microscope has a information of x,y position and its height along the z axis cross sectioned image plane. 3D image was constructed using the continuous image combination. Major feature was acquired from a fault image and measured area, thickness of cell wall, shape and unit cell volume. The shape of plant cell was consist of multiple facet shape. Through this measured information, it is possible to construct for structure shape of unit plant cell. This micro unit image processing techniques will contribute to the filed of agricultural mechanical property and will use to construct unit cell model of each agricultural products and information of boundary will use for finite element analysis on unit cell image.

• Journal of the Korean Chemical Society
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• v.39 no.9
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• pp.685-691
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• 1995

EHMACC and EHPC programs written in VAX version to calculate the tight-binding extended Huckel method is converted into the micro-soft fortran available to PC. The band calculation of LaNiO3 unit cell and extended ($2{\times}2{\times}1$) cell with perovskite structure is made by the PC/386 and PC/486. The calculation is also made for the DOS and the COOP. It is supposed that the electronic property of $LaNiO_3$ is semiconductor along to the ${\Gamma}{\rightarrow}H,\;H{\rightarrow}N,\;and\;N{\rightarrow}{\Gamma}(2D)$ direction with band gap about 0u.35 eV, while metal property in ${\Gamma}{\rightarrow}P\;and\;P{\rightarrow}N(3D)$ direction. The oxygen atom property in $LaNiO_3$ is more effectively affected by oxygen atom position than defect of nickel atom.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.6-8
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• 2004

Recently, the PM type stepping motor preferred solution for many small electronics position determination devices since it is small in size. Thus, there are glowing demands for permanent magnet(PM) type stepping motor that greater mechanical output, smaller size. This paper deals with a study of the miniaturization of the PM type stepping motor with claw-poles. We introduced the small-sized PM type stopping motor that has new structure and analyzed the magnetic characteristic of it versus general type model using 3-D finite element analysis(FEA).

• Genomics & Informatics
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• v.19 no.3
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• pp.29.1-29.10
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• 2021

In our previous studies, we have demonstrated the association of certain variants of the thyroid-stimulating hormone receptor (TSHR), thyroid peroxidase (TPO), and thyroglobulin (TG) genes with congenital hypothyroidism. Herein, we explored the mechanistic basis for this association using different in silico tools. The mRNA 3'-untranslated region (3'-UTR) plays key roles in gene expression at the post-transcriptional level. In TSHR variants (rs2268477, rs7144481, and rs17630128), the binding affinity of microRNAs (miRs) (hsa-miR-154-5p, hsa-miR-376a-2-5p, hsa-miR-3935, hsa-miR-4280, and hsa-miR-6858-3p) to the 3'-UTR is disrupted, affecting post-transcriptional gene regulation. TPO and TG are the two key proteins necessary for the biosynthesis of thyroid hormones in the presence of iodide and H₂O₂. Reduced stability of these proteins leads to aberrant biosynthesis of thyroid hormones. Compared to the wild-type TPO protein, the p.S398T variant was found to exhibit less stability and significant rearrangements of intra-atomic bonds affecting the stoichiometry and substrate binding (binding energies, ΔG of wild-type vs. mutant: -15 vs. -13.8 kcal/mol; and dissociation constant, K_d of wild-type vs. mutant: 7.2E^-12 vs. 7.0E^-11 M). The missense mutations p.G653D and p.R1999W on the TG protein showed altered ΔG(0.24 kcal/mol and 0.79 kcal/mol, respectively). In conclusion, an in silico analysis of TSHR genetic variants in the 3'-UTR showed that they alter the binding affinities of different miRs. The TPO protein structure and mutant protein complex (p.S398T) are less stable, with potentially deleterious effects. A structural and energy analysis showed that TG mutations (p.G653D and p.R1999W) reduce the stability of the TG protein and affect its structure-functional relationship.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.4
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• pp.170-175
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• 2001

It was possible to grow the $Al_{2}O_{3}$ based $Y_{3}A_{5}O_{12}(YAG),ZrO_{2}$ binary and ternary eutectic fibers using micro-pulling down method with a growing rate of 0.1~15 mm/min. While $Al_{2}O_{3}/ZrO_{2}$ showed cellular-lamellar structure, $Al_{2}O_{3}$/YAG and $Al_{2}O_{3}$/YAG/$ZrO_{2}$ternary eutectic fibers showed homogeneous Chinese script lamellar structures. The microstructures of $Al_{2}O_{3}/ZrO_{2}$ binary eutectic fibers changed with solidification rate from lamellar pattern to cellular structure. The interlamellar spacing agreed with the inverse-square-root dependance on pulling rate according to $\lambda$=$kv_p\;{-1/2}$. $Al_{2}O_{3}/ZrO_{2}$ binary eutectic fibers recorded the highest tensile strength of about 1560MPa at room temperature. $Al_2O_3/YAG/ZrO_2$ternary eutectic fiber showed excellent thermal stability to $1200^{\circ}C$ without significant decrease. The maximum strength of ternary eutectic fibers recorded were 1100MPa at $25^{\circ}C$ and 970MPa at $1200^{\circ}C$, respectively.

• Journal of Korea Foundry Society
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• v.40 no.3
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• pp.61-65
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• 2020

Rheo-diecasting with stirring has been used in many material industries. As the 4th Industrial Revolution approaches the world, eco-friendly high-strength and light-weight materials become more important. Casting methods have been studied and used for aluminum-alloy automobile parts. This study carried out the effect analysis of the micro-structure and mechanical properties, such as yield/ultimate tensile strength, elongation, and hardness, of A356 using the 6-pole EMS (electro-magnetic stirring) casting process with a high electromagnetic force. As a result, the hardness and elongation of the A356 after T6 heat-treatment show a significant improvement, respectively, by 20% and 50%.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2001.05a
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• pp.224-231
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• 2001

Hydrogenated amorphous carbon films were deposited by ERC-PECVD with deposition conditions, such as ECR power, gas composition of methane and hydrogen, deposition time, and substrate bias voltage. The characteristics of the film were analyzed using the AES, ERDA, FTIR. Raman spectroscopy and micro hardness tester. From the results of AES and ERDA, the elements in the deposited film were confirmed as carbon and hydrogen atoms. FTIR spectroscopy analysis shows that the atomic bonding structure of a-C:H film consisted of sp³and sp²bonding, most of which is composed of sp³bonding. The structure of the a-C:H films changed from CH₃bonding to CH₂or CH bonding as deposition time increased. We also found that the amount of dehydrogenation in a-C:H films was increased as the bias voltage increased. Raman scattering analysis shows that integrated intensity ratio (I/sub D//I/sub G/) of the D and G peak was increased as the substrate bias voltage increased, and films hardness was increased.

• Food Science of Animal Resources
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• v.43 no.4
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• pp.712-720
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• 2023

Osteoporosis is a growing global health concern primarily associated with decreased estrogen in postmenopausal women. Recently, some strains of probiotics were examined for potential anti-osteoporotic effects. This study intended to evaluate the impacts of Lactiplantibacillus plantarum MGE 3038 strain (MGE 3038) in ovariectomized rats. For this purpose, twelve weeks old female Wistar rats (n=21; 250-300 g) were divided into 3 groups; ovariectomy (OVX) group, OVX/MGE 3038 group and Sham group (control). In these groups; two went through respective OVX and one had daily MGE 3038 administration through oral gavage. Prior to 16 weeks after OVX, we collected blood samples and extracted the tibiae. We scanned the extracted tibiae by in-vivo micro-computed tomography (micro-CT) and evaluated pathology by hematoxylin and eosin (H&E) and Masson's trichrome staining. The serum levels of C-telopeptide of type I collagen (CTX), osteocalcin (OC), and the receptor activator of nuclear factor-κB ligand (RANKL) were examined. The OVX/MGE 3038 group showed increases in bone mineral density, trabecular bone volume, trabecular number, and trabecular thickness (Tb.Th), and a decrease in trabecular spacing than the OVX group. However, OVX/MGE 3038 group and control group were measurably comparable in Tb.Th. Micro-CT, H&E, and Masson's trichrome findings exhibited increased preservation and maintenance of trabecular bone structure in the OVX/MGE 3038 group in comparison to the OVX group. In serum, the levels of CTX, OC and RANKL were significantly different between the OVX and OVX/MGE 3038 groups. Taken together, L. plantarum MGE 3038 could be helpful for the treatment of osteoporosis.