• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.123-129
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• 2003

Recently, the life cycle of products is rapidly shortened and then the disposal of the used mold applied in development of the product is a difficult thing. In this study, we proposed the feasibility of new three plate type mold structure for recycling by analyzing of the existing standard mold base. And in order to apply new three plate mold structure in mold design and making. we constructed the specifications for mold parts such as runner stripper plate, cavity plate, core plate and slide core unit. Also, we confirmed the possibility of recycling mold base by testing a used three plate mold for audio front panel.

• Korean Journal of Head & Neck Oncology
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• v.36 no.2
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• pp.45-50
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• 2020

Extranodal Natural Killer (NK)/T-cell lymphoma, nasal type, is a subtype of non-Hodgkin lymphoma, strongly associated with Epstein-Barr virus. Extranodal NK/T-cell lymphoma mostly affects the nasal cavity and there has been no report of the disease's occurrence at the base of tongue. Here we report a case of 43-year-old man who presented with a diffuse ulcerative lesion at the base of tongue. Because the patient had oral bleeding, tracheostomy and lingual artery ligation was performed via a transcervical approach to control bleeding and protect the upper airway. We performed a deep biopsy through the lateral pharyngotomy approach, and finally, the patient was diagnosed with extranodal NK/T-cell lymphoma, nasal type. We report this rare case of extranodal NK/T cell lymphoma at the base of tongue with a literature review.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.83-86
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• 2003

The chemical laser system makes use of a diffusion type chemical reaction, so a fuel is separated from an oxidant by some gap, which is base in this system. In this study, the effects of base on the population inversion that is one of the most important things in the chemical laser system are numerically investigated. The results are discussed by comparison with three cases of base sizes; 0.4mm, 0.8mm and 1.6mm. Major results reveal that the range of population inversion also increases almost linearly in the transitions; DF$^{(2)}$ -DF$^{(1)}$ and DF$^{(3)}$ -DF$^{(2)}$ as the length of base becomes longer.

• Archives of Craniofacial Surgery
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• v.22 no.5
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• pp.232-238
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• 2021

Background: Galeal or temporalis muscle flaps have been traditionally used to reconstruct skull base defects after tumor removal. Unfortunately, these flaps do not provide sufficient vascularized tissue for a dural seal in extensive defects. This study describes the successful coverage of large skull base defects using anterolateral thigh (ALT) free flaps. Methods: This retrospective study included five patients who underwent skull base surgery between June 2018 and June 2021. Reconstruction was performed using an ALT free flap to cover defects that included the intracranial space and extended to the frontal sinus and cribriform plate. Results: There were no major complications, such as ascending infections or cerebrospinal leakage. Postoperative magnetic resonance imaging showed that the flaps were well-maintained in all patients. Conclusion: Successful reconstruction was performed using ALT free flaps for large anterior skull base defects. In conclusion, the ALT free flap is an effective option for preventing communication between the nasal cavity and the intracranial space.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.1
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• pp.26-34
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• 1996

Copulation process, fertilization and gestation of the viviparous teleost surfperch, Ditrema temmincki were investigated by using photomicroscopy. Samples were collected from the vicinity of Suyoung Bay, Pusan, Korea from May 1992 to August 1993. During the copulation period, the copulatory organs were protruded at the base part of right and left soft ray of the anal fin in mature male. Secondary sexual characteristics index (SSCI) of male participated in copulation was above 3.5. Mature oocytes appeared only in the female containing sperms in the ovarian cavity. Transport of the spermatozoa into the ovarian cavity during copulation belonged to a spermatophore type. After copulation, spermatozoa remained in the ovarian cavity for about one month untill fertilization. Fertilization occured within the follicular cavity. Fertilized eggs were released into the ovarian cavity where they developed during gestation period. Developmental sequence of the female was as following: fertilization-ovulation-hatching-parturition. Right before parturition, the total length (TL) of the embryo was about 63.0 mm. When TL of maternal body was 20.0 cm, the mean numbers of the embryo were 18. The numbers of the embryo were positively related to the maternal body size.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.43-46
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• 2005

Micro molding technology is a promising mass production technology for polymer based microstructures. Mass production technologies such as the micro injection/compression molding, hot embossing, and micro reaction molding are already in use. In the present study, we have developed a numerical analysis system to simulate three-dimensional non-isothermal cavity filling for hot embossing, with a special emphasis on the free surface capturing. Precise free surface capturing has been successfully accomplished with the level set method, which is solved by means of the Runge-Kutta discontinuous Galerkin (RKDG) method. The RKDG method turns out to be excellent from the viewpoint of both numerical stability and accuracy of volume conservation. The Stokes equations are solved by the stabilized finite element method using the equal order tri-linear interpolation function. To prevent possible numerical oscillation in temperature Held we employ the streamline upwind Petrov-Galerkin (SUPG) method. With the developed code we investigated the detailed change of free surface shape in time during the mold filling. In the filling simulation of a simple rectangular cavity with repeating protruded parts, we find out that filling patterns are significantly influenced by the geometric characteristics such as the thickness of base plate and the aspect ratio and pitch of repeating microstructures. The numerical analysis system enables us to understand the basic flow and material deformation taking place during the cavity filling stage in microstructure fabrications.

• Tribology and Lubricants
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• v.13 no.1
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• pp.21-27
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• 1997

The friction and wear behavior of undulated surfaces made of tin base babbit are examined experimentally at the low sliding speed with severe loading condition. Steel is used as counterface disk material under pin-on-disk type sliding condition. Undulated surfaces can improve the friction and wear properties under dry friction condition since undulated surfaces trap wear particles in their cavities and prohibit wear particles from agglomerating. However, under boundary lubrication condition, friction and wear properties of undulated surfaces are inferior to those of flat surfaces. It is shown that land width and the ratio of wear volume to cavity volume are the most important factors in friction behavior of undulated surfaces under dry friction condition, and there exists optimum land width minimizing friction and wear of undulated surfaces.

• Korean Journal of Veterinary Research
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• v.30 no.4
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• pp.395-400
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• 1990

A female Korean native calf with diprosopus was examined macroscopically and radiographically. Anterior head duplication (diprosopus) was observed and all structures caudal to it were normal. She had two complete mouths, four eyes and three ears. Single tongue was present in each oral cavity. The two tongues were joined at their base just posterior to the single epiglottis. Both oral cavities led jointly into a common pharynx and one esophagus. One laryngeal cavity communicated with one common trachea. The lower jaws were immobile because of overlapping mandibular rami. The atlas was complete, and two anterior articular cavities articulated with the lateral condyles of the occipital bones of each skull. The cerebrums were fused each other at their caudal portion, and the giri and sulci were underdeveloped. The cerebellums were also completely fused, and they had not characteristic appearance of the vermis. The spinal cord showed normal appearance.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.817-832
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• 2021

In this paper, a simple practical method to estimate the drag of Super-Cavitating Underwater Vehicles (SCUV) is proposed that can obtain the drag with only principal dimensions in an initial design stage. SCUV is divided into cavitator, forebody, afterbody, base, and control fin and the drag of each part is estimated. The formulas for the drag coefficient are proposed for the disk and cone type cavitators and wedges used as control fins. The formulas are a function of cavitation number, cone or wedge angle, and Reynolds number. This method can confirm the drag characteristics of SCUV that the drag hump appears according to the coverage of the body by the cavity and the cavitator drag remains only when the entire body is covered by cavity. Applying this method to SCUV of various shapes, it is confirmed that the effects of cavitating and non-cavitating conditions, cavitator and body shape, and speed could be found.

• Korean Journal of Materials Research
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• v.33 no.2
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• pp.47-53
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• 2023

When exposed to different types of bacteria in the oral cavity, denture based resins are prone to bacteria attachment. The purpose of this study was to investigate the physical, biological, and antimicrobial properties of denture base resins coated with Peony extract (200, 400, and 600 ㎍/mL). Specifically, the surface properties (microhardness, contact angle, and color change of the coated specimens), cell cytotoxicity (measured using MTT assay), and antimicrobial activity (against S. mutans (Streptococcus mutans) and C. albicans (Candida albicans) using a growth inhibition assay) were evaluated. The polyphenol content was measured using ultraviolet-visible (UV-vis) spectrometry. The experimental groups (specimens coated with Peony extract) and a control group (specimens coated without Peony extract) were statistically compared using a one-way analysis of variance and Tukey's post-hoc tests. No statistically significant differences in surface properties or cell cytotoxicity were observed, which demonstrated their biocompatibility. Conversely, a statistically significant difference in antimicrobial activity was observed between the experimental and control groups after 48 h. This confirms the antimicrobial activity of the denture base resin coated with Peony extract and demonstrates that it is a promising dental material for preventing stomatitis.