• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.283-290
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• 2016

This study presents an 8x four-group inner-focus zoom lens with one-moving group for a compact camera by use of a focus tunable lens (FTL). In the initial design stage, we obtained the powers of lens groups by paraxial design based on thin lens theory, and then set up the zoom system composed of four lens modules. Instead of numerically analytic analysis for the zoom locus, we suggest simple analysis for that using lens modules optimized. After replacing four groups with equivalent thick lens modules, the power of the fourth group, which includes a focus tunable lens, is designed to be changed to fix the image plane at all positions. From this design process, we can realize an 8x four-group zoom system having one moving group by employing a focus tunable lens. The final designed zoom lens has focal lengths of 4 mm to 32 mm and apertures of F/3.5 to F/4.5 at wide and tele positions, respectively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.3
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• pp.276-279
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• 2001

Osteoma is defined as a benign neoplasm of bony tissue. Osteomas are divided into two groups: central and peripheral by origin, compact and cancellous by histopathologic findings. Solitary osteoma of jaw bone, not related with Gardner syndrom, is relatively uncommon. We present two cases of huge solitary peripheral osteomas: compact type exophyting osteoma on the inferolingual side of mandibular angle and cancellous type on the residual ridge of posterior maxilla, which is extremely rare.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.50 no.1
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• pp.13-26
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• 2024

Objectives: The aim of this study was to perform a comparative analysis of the ultrastructural and chemical composition of sialoliths, tonsilloliths, and antroliths and to describe their growth pattern. Materials and Methods: We obtained 19 specimens from 18 patients and classified the specimens into three groups: sialolith (A), tonsillolith (B), and antrolith (C). The peripheral, middle, and core regions of the specimens were examined in detail by histology, micro-computed tomography (micro-CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and transmission electron microscopy (TEM). Results: In the micro-CT, group A showed alternating radiodense and radiolucent layers, while group B had a homogeneous structure. Group C specimens revealed a compact homogeneous structure. Histopathologically, group A showed a laminated, teardrop-shaped, globular structure. Group B demonstrated degrees of immature calcification of organic and inorganic materials. In group C, the lesion was not encapsulated and showed a homogeneous lamellar bone structure. SEM revealed that group A showed distinct three layers: a peripheral multilayer zone, intermediate compact zone, and the central nidus area; groups B and C did not show these layers. The main elemental components of sialoliths were O, C, Ca, N, Cu, P, Zn, Si, Zr, F, Na, and Mg. In group B, a small amount of Fe was found in the peripheral region. Group C had a shorter component list: Ca, C, O, P, F, N, Si, Na, and Mg. TEM analysis of group A showed globular structures undergoing intra-vesicular calcification. In group B, bacteria were present in the middle layer. In the outer layer of the group C antrolith, an osteoblastic rimming was observed. Conclusion: Sialoliths had distinct three layers: a peripheral multilayer zone, an intermediate compact zone and the central nidus area, while the tonsillolith and antrolith specimens lacked distinct layers and a core.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.3
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• pp.550-568
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• 1995

The purpose of this study was to observe the effects of early functional on bone formation around titanium plsama sprayed IMZ implants. 15 IMZ implants were inserted on the mandibular premolar areaa in 5 mondgrel dogs. The inplants were divided into 4 groups according to it’s loading schedule : Temporary abutments were connected for functional loading 6weeks, 9weeks, and 12weeks after implants installation in group I, II, and III, respectively. Abutments were not connected in the control group. After polyfluorochrome sequential labeling, all animals were sacrificed and bone sections includig implants and the 1st. molar were removed and processed for histologic evaluation. From light and fluorescence microscopic evaluation as well as histomorphometric and EPMA analysis, following results were obtained : 1. Light microscopically, the osteoid tissues were observed much in the compact bone of unloaded group, and cancellous bone formation observed more in early loaded group. 2. Calcification and remodeling of bone took place faster in loaded group, especially in 6 weeks group. 3. Moderate to severe marginal bone resorption was observed in 6 weeks group, mainly on buccal crest. 4. There was no difference in the percentages of bone-to-metal contact among the experimental groups. 5. In quantitative analysis using EPMA, there was no difference in the content of calcium and phosphorus among the experimental groups, regardless of distance.

• Journal of Periodontal and Implant Science
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• v.34 no.2
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• pp.377-392
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• 2004

The purpose of this present study was to investigate the effect of autogenous bone with histological evaluation of regenerated bone after sinus elevation. The study involved genaral healthy 6 patients participated in this study and were treated with 2-stage sinus elevation procedures using a combination of demineralized freezed-dried bone allograft (DFDBA) and coralline calcium carbonate with or without autogenous bone. At 6months after sinus elevation, bone specimens were obtained and stained with Hematoxylin-Eosin for light microscopic evaluation. The results of this study were as follows : 1. Autogenous bone grafts present trabecular patterns at 6 months in test groups, consist of woven bone and lamellar bone, but more compact than control groups. 2. Resorption of bone graft particles, osteoblast-like cells, newly formed osteoid tissue were observed at 6 months in test groups, but seems to be more frequently than control groups. 3. New osteoid tissue was formed from the surface of graft materials and gradually expanded around them. 4. The appearance of connective tissue around graft materials was densely formed, but more prominent in test groups than control groups. 5. Bone graft particles were resorbed incompletely and slight inflammatory infiltrate, newly formed capillaries, and adipocytes were observed. From the above results, autogenous bone is effective in bone regeneration after sinus elevation, could provide favorable conditions in implant placement.

• Journal of the Korean Society of Costume
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• v.67 no.3
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• pp.66-80
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• 2017

The headdress is one of the most important clothing characters in China, as it was used to distinguish the 55 minority groups in China. Each minority group has a unique headdress culture. Among the 55 minority groups, the Zang, the Yi, and the Miao focus their ethnic costumes on the headdress, and have a more distinctive headdress culture compared to be other nationality groups. The Yi is one of the minority groups that linvd in Southwest China. They usually lived in compact communities in Sichuan, Yunnan, and Guizhou provinces, as well as the Guangxi Zhuang Autonomous region. The total population of the Yi is the sixth largest among the 55 minority groups. Modern scholars believe that the Yi people are descendants of the ancient Qiang people, which is a group that lived in Northwest China six or seven thousand years before. It is believed that the Qiang went down to the southern part of China and allied with the aboriginals in that region, and this group of people became the Yi, Due to its long history, cultural background, and the large number of people and settlements, they have produced a unique costume culture. The women's headdress culture is considered to be the one of the most important characteristics of their costume culture. There are four forming element of the Yi women's headdress, religious faith, myths, geographical distribution and customs & festivals. The first three elements play an important role in the protection and spread of headdress, while the fourth element provides potential for the modern headdress development. Because of much influence factors, more than 100 types of Yi women headdresses have developed. Depends on categories, Yi woman headdress can be divided into kerchief, hat, fascinator and other accessories wore on the hand. This study investigated the development of the Yi women's headwear, and screened and analyzed representative Yi women accessories, such as the headscarf, hat, and fascinator. This analysis will provide basic materials for further studies of Yi women's headdress or costume.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.123.2-123.2
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• 2012

We investigate the solar flare occurrence rate and daily flare probability in terms of the sunspot classification supplemented with sunspot area and its changes. For this we use the NOAA active region data and GOES solar flare data for 15 years (from January 1996 to December 2010). We consider the most flare-productive eleven sunspot classes in the McIntosh sunspot group classification. Sunspot area and its changes can be a proxy of magnetic flux and its emergence/cancellation, respectively. We classify each sunspot group into two sub-groups by its area: "Large" and "Small". In addition, for each group, we classify it into three sub-groups according to sunspot area changes: "Decrease", "Steady", and "Increase". As a result, in the case of compact groups, their flare occurrence rates and daily flare probabilities noticeably increase with sunspot group area. We also find that the flare occurrence rates and daily flare probabilities for the "Increase" sub-groups are noticeably higher than those for the other sub-groups. In case of the (M+X)-class flares in the 'Dkc' group, the flare occurrence rate of the "Increase" sub-group is three times higher than that of the "Steady" sub-group. Our results statistically demonstrate that magnetic flux and its emergence enhance the occurrence of major solar flares.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.3
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• pp.8-22
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• 1990

This study was performed to evaluate the histopathologic changes of the rabbit tibial compact bone using internal irrigation with both cold and room - temperature saline on drilling. The medial surface of the rabbit tibia was drilled with specially designed pilot drill (2.0mm in diameter) at 300 rpm. When drilling, two different temperature salines were injected (experimental group I : $4^{\circ}C$ saline, experimental goup Ⅱ : room - temperature saline). And the control group was drilled without cooling agent. The three rabbits in each two experimental and control groups were sacrificed 1, 2, 4, and 8 weeks after. The bone tissues including the bony defects were fixed with 10% neurtal buffered formalin, decalcified with formic acid, embedded in paraplast, and sterile sectioned at 5-6${\mu}m$. And then tissue specimens were stained with H - E and observed under light microscope. The results were as follow : The experimental groups showed early bone repair than the control group at all intervals. They underwent the same course of bone repair until 4 weeks. But the experimental group I showed slightly better bone maturation than the experimental group Ⅱ at 8 weeks.

• Genomics & Informatics
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• v.5 no.3
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• pp.95-101
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• 2007

In this paper, we consider the variable selection methods in the Cox model when a large number of gene expression levels are involved with survival time. Deciding which genes are associated with survival time has been a challenging problem because of the large number of genes and relatively small sample size (n<

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.629-637
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• 2015

Compact system cameras (CSCs) are commonly used nowadays and feature enhanced video functions and thin yet light interchangeable lenses. They differ from digital single-lens reflex (DSLR) cameras in their lack of mirror boxes. CSCs, however, have autofocus (AF) speeds lower than those of conventional DSLRs, requiring weight reduction of their AF groups. To ensure the marketability of large telephoto zoom lenses with fixed f/2.8 regardless of field angle variation, in particular, light weight AF groups are essential. In this paper, we introduce a paraxial optical design method and present a new, large, telephoto zoom lens with f/2.8 regardless of the field angle variation, plus a lightweight AF group consisting of only one lens. Using the basic paraxial optical design and optimization methods, we fabricated a new and lighter zoom lens system, including a single-lens, lightweight AF group with almost the same performance.