• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.469-473
• /
• 2009

The supersonic gas ejector, as gas dynamic appliance, has been applied for a long time because of simplicity and reliability. However, for the prediction of ejector performances with given parameters, that is, working gas pressure and the nozzle shape, it is necessary to raise accuracy of modelling for properties of ejector gas flow. The purpose of the represented work is to compare one-dimensional modelling and numerical results with experimental results. The ejector with a conic nozzle has been designed and tested (Mach number at the nozzle exit section was 3.31, the nozzle throat diameter - 6 mm). Working gas - nitrogen, was brought from system of gas bottles. Diameter of the mixture chamber at the nozzle exit section was limited by condensation temperature of nitrogen and equaled 20 mm. The one-dimensional theory predicted the minimal starting pressure equaled 8.18 bar (absolute) and 0.051 bar in the vacuum chamber. Accordingly the minimal starting pressure was 9.055 bar and 0.057 in the vacuum chamber bar have been fixed in experiment.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.3
• /
• pp.292-297
• /
• 2011

MPF(Magnetic pulse forming) process refers to the high velocity and high strain rate deformation of a low-ductility materials driven by electromagnetic forces that are generated by the rapid discharge current through forming coil. The goal of this study was to find the characteristics of dynamic behavior of workpiece and to find the main design process on MPF using bar forming coil. For these purposes, thin Al5053 sheet were used for the experiment. The measured strain data were analyzed by developed electromagnetic FE-model. The main design parameter is location of coil, electromagnetic force. In case of the bar forming coil, there exists the dead regions where the low electromagnetic force applied on the workpiece.

• The Journal of Korean Medical History
• /
• v.27 no.1
• /
• pp.135-156
• /
• 2014

Through a simple translation and analysis of the "Su$\acute{s}$uta-saṃhit$\bar{a}$(The fascinating tales) S$\bar{u}$trasth$\bar{a}$na(The Introduction)", I have summarized the results of the research into the $\bar{A}$yurveda Herbal theory. 1. The title of chapter 40 is "dravya-rasa-guṇa-vip$\bar{a}$ka-vij$\tilde{n}$anīya(Medcation Taste Nature Effects Digestion)", and it states theoretical knowledge on materia medica. It says that 'matter' is the most important thing, and that it decides the curing effect. Although it does acknowledge the reason behind the doctors that emphasized things like 'taste', it mainly has a critical tone. The difference in philosophies and medical theory can be seen when we compare this to the "Caraka-saṃhit$\bar{a}$", 'theory on taste'. 2. The title of chapter 41 is "dravya-vi$\acute{s}$eṣa-vij$\tilde{n}$anīya(A Discussion on the Characteristics of Materia Medica)", and the contents of the chapter have a similar tone to the thoughts of the S$\bar{a}$mkhya(數論派). All 'matter' was created by the combination of the five elements of earth, water, fire, wind, and ether, and the predominant element makes it have an earth, water, fire, wind, or ether nature. Earth has an unmoving and down going nature, and makes the body strong. Water has an irrigating nature, and moistens the tissue and induces secretion and excretion. Fire has an upward-going nature, and improves sight and complexion. Wind relaxes and dries the body, and makes the mind and body agile. Ether gives flexibility, porosity, and candidness. The title of chapter 42 is "rasa-vi$\acute{s}$eṣa-vij$\tilde{n}\bar{a}$nīya(A Discussion on the Types of Rasa(taste))". "Rasa" is an important concept in $\bar{A}$yurveda. Sometimes it is translated as 'one of the seven types of bodily tissue' and seen as chyle, and sometimes it is seen as the tastes that can be felt with the tongue such as spicy, sweet, sour, bitter, salty, and astringent(澁). Volume 1, chapter 42 of the "Caraka-saṃhit$\bar{a}$" is dedicated to the "types of taste", and in chapter 26, it theorizes the concept of 'taste'.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.27 no.2
• /
• pp.223-231
• /
• 2011

The purpose of this case report is to introduce new attachment system(milled titanium bar with $Locator^{(R)}$ attachment) for implant supported overdenture in maxillary edentulous patients. A 56-years-old male patient visited the hospital due to the mobility of his maxillary fixed partial dentures(10-unit bridge). Including temporomandibular joint(TMJ), there was no specific PMHs to influence dental treatment. In radiographic and clinical evaluation, there was a severe bone resorption and mobility in maxillary teeth. Accordingly all the remaining maxillary teeth was extracted and fabrication of implant supported overdenture was planned. The milled titanium bar with $Locator^{(R)}$ was designed as an attachment system, considering the stability and retention of denture, masticatory efficiency, oral hygiene care, esthetics, pronunciation, and patient's financial state. The milled titanium bar was manufactured using CAD/CAM technology, and $Locator^{(R)}$ attachment connected to the bar by tap & drill method. For over 1-year, in terms of function and esthetics, satisfactory result was obtained.

• Korean Journal of Optics and Photonics
• /
• v.32 no.5
• /
• pp.230-234
• /
• 2021

Relief of thermal stress has received great attention, to improve the beam quality and stability of high-power laser diodes. In this paper, we investigate a microtrench structure engraved around a laser-diode chip-on-submount (CoS) to relieve the thermal stress on a laser-diode bar (LD-bar), using the SolidWorks® software. First, we systematically analyze the thermal stress on the LD-bar CoS with a metal heat-sink holder, and then derive an optimal design for thermal stress relief according to the change in microtrench depth. The thermal stress of the front part of the LD-bar CoS, which is the main cause of the "smile effect", is reduced to about 1/5 of that without the microtrench structure, while maintaining the thermal resistance.

• Journal of Korean Physical Therapy Science
• /
• v.31 no.3
• /
• pp.15-22
• /
• 2024

Background: This study aimed to investigate the immediate effects of Flexi-bar exercise on plantar pressure and Center of Pressure in a standing position. Design: Single group pre-post test design Methods: Thirty healthy adult participants aged 20 to 35 years old and no recent musculoskeletal injuries were included in this single-group pre-post design study. Plantar pressure and COP data were collected using the WinTrack system before and after Flexi-bar exercise. Participants performed Flexi-bar exercises in both anterior-posterior and lateral directions for 30 seconds each. Results: The results revealed significant changes in plantar pressure and COP after Flexi-bar exercise. The support area of the left foot significantly increased (p<0.05), and a significant decrease in mean pressure was observed in the right foot (p<0.05). The total COP path length and area significantly decreased (p<0.05). Furthermore, there was a significant decrease in COP velocity along the X and Y axes (p<0.05). These findings suggest that Flexi-bar exercise can enhance plantar pressure distribution and COP movement patterns, contributing to improved balance ability. Conclusion: Flexi-bar exercise, performed in a standing position, has the potential to improve plantar pressure and COP characteristics. This exercise may serve as a valuable tool for enhancing balance ability. Further research is needed to explore the long-term effects and sustainability of these improvements.

• Journal of ILASS-Korea
• /
• v.21 no.3
• /
• pp.121-129
• /
• 2016

The advantages of the common rail fuel injection system architecture have been recognized since the development of the diesel engine. In common rail systems, a high-pressure pump stores a reservoir of fuel at high pressure up to and above 2000 bar. And solenoid or piezoelectric valves make possible fine electronic control over the fuel injection time and quantity, and the higher pressure that the common rail technology makes available provides better fuel atomization. In this study, the direct needle-driven piezo injector was investigated for accomplishing injection pressure of 1800 bar by optimal design by simplification of component and changing number of springs and plates of DPI. It was found that a direct needle-driven piezo injection system features the prototype DPI for passenger vehicle to operate at 1800 bar of injection pressure.

• Korean Journal of Heritage: History & Science
• /
• v.51 no.3
• /
• pp.32-53
• /
• 2018

The $Sh{\bar{o}}s{\bar{o}}-in$(正倉院) is the detached storage building for Japanese treasures that belongs to $T{\bar{o}}dai-ji$ in Nara, Japan. The reason why $Sh{\bar{o}}s{\bar{o}}-in$ collections are drawing attention is that Japanese artifacts, sculptures, paintings, and other objects that were introduced through the Silk Road, such as Sasanian Persia and India, and those that were introduced from the Unified Silla and Tang China. In addition, hundreds of well-preserved documents of $Sh{\bar{o}}s{\bar{o}}-in$ collections play an important role as a historical reference material covering not only the social situation of the time but also the history of exchange of cultural diplomacy and the change of Buddhist doctrine. In particular, some of collections of $Sh{\bar{o}}s{\bar{o}}-in$ were made in China and may have been imported or received as gifts, but many of the artifacts made in Baekje and Unified Silla are becoming more and more important. This paper examined the research status of $Sh{\bar{o}}s{\bar{o}}-in$ metal crafts of Korean and foreign scholars, and examined the association with the relics of $Sh{\bar{o}}s{\bar{o}}-in$ through metal crafts excavated from the Korean Peninsula. The research on the future direction of $Sh{\bar{o}}s{\bar{o}}-in$ collections should be summarized as follows. 1. Systematization of state-level support and single window for the research of $Sh{\bar{o}}s{\bar{o}}-in$ collections 2. Accurate listing and database of $Sh{\bar{o}}s{\bar{o}}-in$ collections 3. The positive implementation of joint research with Japan and invitation of researchers related to $Sh{\bar{o}}s{\bar{o}}-in$ collections 4. The exchange exhibition between the Korean National Treasures and the $Sh{\bar{o}}s{\bar{o}}-in$ collections 5. Expansion of the research base through the publication and support of books related to $Sh{\bar{o}}s{\bar{o}}-in$ collections.

• The Journal of Korean Academy of Prosthodontics
• /
• v.54 no.2
• /
• pp.146-151
• /
• 2016

In patients with fully edentulous maxilla, fabrication of implant-supported overdenture can be a viable treatment option, when a minimum of six implants were strategically placed. Among several attachment systems used for implant-supported overdentures, milled-bars prevent rotational movement of denture, thus showing great stability, and have the advantage of splinting multiple implants with each other. In this case report, a milled-bar supported overdenture was fabricated for a patient suffering from condition of fully edentulous maxilla with severe ridge resorption in the anterior residual ridge. Seven implants composed of three different systems were effectively utilized by CAD/CAM customized abutment and cement-retained milled bar.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.27 no.2
• /
• pp.45-54
• /
• 2021

Background: The purpose of this study was to investigate the effects of flexi-bar exercise on shoulder pain, dysfunction, quality of life, and range of motion of women with breast cancer surgery. Methods: A total of 42 female patients who had breast cancer were included in this study. By drawing lots, subjects were divided into a flexi-bar exercise group (FBG, n=21) and a general breast cancer group (GBG, n=18). The effects of flexi-bar exercise on patients were evaluated in terms of the visual analogue scale (VAS), the shoulder pain and disability index (SPADI), the European organization for the research and treatment of cancer quality of life questionnaire (EORTC QLQ-C30), the breast cancer specific EORTC quality of life questionnaire (EORTC QLQ-BR23), and range of motion (ROM), all of which were measured pre- and post- intervention followed by evaluation. Results: A significant increase was pain, functional disability level, quality of life, ROM within the two groups (p<.01). There were pain, functional disability level, quality of life, ROM post test then invention were significant between the two groups(p<.01). Conclusion: The flexi-bar exercise has a positive treatment effect on breast cancer patients.