• Journal of the Korean Society for Precision Engineering
• /
• v.9 no.1
• /
• pp.106-117
• /
• 1992

In this study, the propagation behaviour and the closure phenomena of physically small surface cracks were investigated by the techinque of the Kikukawa-unloading elastic compliance method using a back face strain gage. The surface cracks initiated and propagated from notched specimens under constant amplitude bending load. The crack shape (aspect ratio) with approximately semi-circular at the early stage was changed to semi-elliptical as the cracks grew larger. The crack depth (a) could be expressed uniquenly by the crack length (c). The dependence of the crack propagation rate on the stress ratio R was strongly related in the lower ${\Delta}K$ range. The deceleration of the surface crack propagation rate was prominent in lower R during the crack length was small. When the propagation rate was rearranged with the effective stress intensity factor range ${\Delta}$K_{eff} the dependence of the crack propagation rate on the stress ratio R was found to be diminshed. These were caused by the crack closure phenomena that was most prominent at the lower propagation rate. The mechanism of crack closure phenomena was dominated by the plasticity-induced mechanism.

• Tribology and Lubricants
• /
• v.35 no.6
• /
• pp.376-381
• /
• 2019

Surface texturing is widely applied to reduce friction and improve the reliability of machine elements. Despite extensive theoretical studies to date, most research has been limited to parallel thrust bearings, mechanical face seals, piston rings, etc. However, most sliding bearings have a convergent film shape in the sliding direction and the hydrodynamic pressure is mainly generated by the wedge action. The results of surface texturing on inclined slider bearings are largely insufficient. This paper is the first part of a recent study focusing on the effect of the groove position on the lubrication performances of inclined slider bearings. We model a slider bearing with one rectangular groove on a fixed pad and analyze the continuity and Navier-Stokes equations using a commercial computational fluid dynamics (CFD) code, FLUENT. The results show that the film convergence ratio and the groove position have a significant influence on the pressure and velocity distributions. There are groove positions to maximize the supporting load with the film convergence ratio and the groove reduces the frictional force acting on the slider. Therefore, the proper groove position not only improves the load-carrying capacity of the slider bearings but also reduces its frictional loss. The present results apply to various surface-textured sliding bearings and can lead to further studies.

• Tribology and Lubricants
• /
• v.35 no.6
• /
• pp.382-388
• /
• 2019

It is currently well known that surface textures act as lubricant reservoirs, entrap wear debris, and hydrodynamic bearings, which can lead to certain increases in load-carrying capacities. Until recently, the vast majority of research has focused on parallel sliding machine components such as thrust bearings, mechanical face seals, piston rings, etc. However, most sliding bearings have a convergent film shape in the sliding direction and their hydrodynamic pressure is mainly generated by the wedge action. Following the first part of the present study that investigates the effect of groove position on the lubrication performances of inclined slider bearings, this paper focuses on the effects of groove depths and film thicknesses. Using a commercial computational fluid dynamics (CFD) code, FLUENT, the continuity and Navier-Stokes equations are numerically analyzed. The results show that the film thickness and groove depth have a significant influence on the pressure distribution. The maximum pressure occurs at the groove depth where the vortex is found and, as the depth increases, the pressure decreases. There is also a groove depth to maximize the supporting load with the film thickness. The friction force acting on the slider decreases with deeper grooves. Therefore, properly designed groove depths, depending on the operating conditions, can improve the load-carrying capacity of inclined slider bearings as compared to the bearings without a groove.

• Archives of Plastic Surgery
• /
• v.32 no.2
• /
• pp.199-204
• /
• 2005

The nose is the most prominent area of the face, therefore susceptible to trauma and skin cancer. When small sized defect is in nasal tip, it results in disturbance of the facial harmony even if replantation, composite graft, skin graft or median forehead flap has been used for the reconstruction. So it is needed that the best method reconstruction is performed according to the degree of defect or deformity. And at the same time the physiology and anatomy of nose were clarified and its aesthetic subunits were employed. How can we cover the about 3 cm sized nasal defect in nasal tip with cartilage exposure? At first, we can think forehead island flap is most appropriate. We performed 7 cases of the forehead island flap for reconstruction of the defect in nasal tip(4 cases: cancer, 3 cases: trauma) from March, 2001 to August, 2004. This result was satisfactory in the point of texture, color, donor scar, and there were no complication such as wound disruption, infection, flap atrophy, and hematoma. The advantages of forehead island flap are: 1) No injury of deep vessel and nerve, 2) control of shape and volume, 3) Short operation time, 4) primary closure of donor site, 5) one stage operation. Also, forehead island flap can cover the defect in nose where skin graft and local flap can not cover. But, operator always must take care for flap congestion and donor site scar. We thought forehead island flap is one of the best option of reconstruction of nasal tip defect.

• Journal of the Korean Society of Food Culture
• /
• v.1 no.3
• /
• pp.211-218
• /
• 1986

The doma (cutting board) is an essential kitchen utensil. The general doma used at present is not sultable for cutting kimchi-like juicy foods, because It is a nat flat structure. Kimchi juice contains vitamins, organle acids, and lactic acid bacteria, and inhibits Oxidation of flavor of kimchi. In addition, if the juice flows down on the doma during cutting the doma work-table and kimchi bottom is contaminated. In this studies a new type of doma for kimchi. was made in order to minimize the Juice Iou during cutting. This new one baa a two-dimensional function of low due to length slope face and slanted gutter of width. No this new type has been developed worldwide, as far as the present writer is aware. The new one has various effectivenesses: minimixing loss of kimchi juice and contamination of doma work-table and kitchen bottom by kimchi juice, saving water and time to water contaminated cutting board, work-table and diahtowel (hangju). preventing round from falling down frorr doma duing cutting, decreasing damage of cutting the user's finger, cutting by the fixed size and shape. Draining and drying is easy and it is convenient to cut all juicy food.

• Journal of Sasang Constitutional Medicine
• /
• v.24 no.1
• /
• pp.13-20
• /
• 2012

1. Objectives : It is very important to classify people into Sasang constitution correctly in SCM. There have been many researches for this and several tools have been developed for diagnosis of Sasang constitution. In our study, we introduce a new web application for Integrated Sasang Constitutional Diagnosis (ISCD) ${\beta}$-version and algorithm on the base of face, body shape, voice and questionnaire. 2. Development : The web application of ISCD ${\beta}$-version was designed to be used easily for subject, staffs, and oriental medical doctors. For this purpose, we developed a web-application of Integrated Sasang Constitutional Diagnosis ${\beta}$-version using mysql database, tomcat web system, JSP, JAVA, and C++ languages. 3. Current State : The ISCD ${\beta}$-version could be accessed at http://210.218.196.115/SDT/login.jsp. The ISCD ${\beta}$-version consisted of 3 parts, for staffs, subject and oriental medical doctors. The system has been managed since February 2011. Currently 7 oriental hospitals have used the system and 1,439 subjects have been diagnosed by the system. 4. Conclusion and future work : Although many researchers have tried to develop a system or an algorithm for diagnosis of subject's constitution, we could have not used the system based on objective information of human body type, characters, symptoms. In this study, we describe a web application of objective diagnosis algorithm as ISCD ${\beta}$-version. This system may help an oriental medical doctors to make a decision of Sasang constitutional diagnosis easily and correctly.

• Journal of Families and Better Life
• /
• v.22 no.4
• /
• pp.43-61
• /
• 2004

The purpose of this study was to verify the usefulness of kinetic House- Tree- Person drawing as a diagnostic measure for the degree of self-differentiation, which is an essential part of college students' development. Participants for the study were four hundred thirty five(272 male and 163 female) university freshmen enrolled in 4-year colleges located in Pusan. The Participants completed a scale of self-differentiation and a Kinetic House- Tree-Person drawings test. The evaluation system for kinetic House-Tree-Person drawings was established based on the indexes of Buck(1948) and Bums(1972) and used exiting literatures as reference. The data were analyzed using means, standard deviations, t-test, one-way ANOVA, and Scheffe's test. The results obtained from the study are as follows: First, the mean level of college students' self-differentiation was 2.81, which is about average. Some significant gender differences were found in the areas of self-intergration, family projection, and emotional separation. Male students scored higher on self-intergration, whereas female students score higher on family projection and emotional separation. Second. self-differentiation was higher when the student drew a house with smoke coming out of the chimney, a single-story house with flat roof, or with detailed description of curtains, roof and roof tiles. Third, self-differentiation seemed to be higher when branches and fruits were included, when there was no expression of roots, when large crowns and branch openings were presented, and when no slant lines or base lines appeared. Forth, self-differentiation showed ㅁ higher level when the portrait shows eyes, mouth and neck without omission, when it included the whole body instead of face only, and when there was no person with just a profile, a back, or with a stiff posture, and when there was no weak and thin lines. Individuality also marked higher if a person was in motion and than one person was added. Finally, self-differentiation showed significant difference according to the overall harmony of the drawing, ordering of contents, hand pressure, the kind and shape of tree, and presence of other persons. The more harmonious the picture was, and the more family members are added, the higher the level of self-differentiation was.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.13 no.2
• /
• pp.199-202
• /
• 1991

Chin is located on most prominent portion of the face, so make more important esthetic value in impression. So historicaly, many authors had made efforts on correction of deformed chin, termed genioplasty. But those technique have been performed on limited cases, which have normal shape or width of chin. In the cases with more narrow or short chin, location of mental foramen or root of incisors restrict the use of such technique. But modified genioplasty technique we used can be performed without any restriction and change of frontal profile of chin. So we report a case that was performed with modified horizontal step osteotomy for advancement genioplasty, which had been reported by Hinds and Kent, with some complications.

• The korean journal of orthodontics
• /
• v.50 no.5
• /
• pp.346-355
• /
• 2020

The treatment of skeletal Class III malocclusion in adolescents is challenging. Maxillary protraction, particularly that using bone anchorage, has been proven to be an effective method for the stimulation of maxillary growth. However, the conventional procedure, which involves the surgical implantation of mini-plates, is traumatic and associated with a high risk. Three-dimensional (3D) digital technology offers the possibility of individualized treatment. Customized mini-plates can be designed according to the shape of the maxillary surface and the positions of the roots on cone-beam computed tomography scans; this reduces both the surgical risk and patient trauma. Here we report a case involving a 12-year-old adolescent girl with skeletal Class III malocclusion and midface deficiency that was treated in two phases. In phase 1, rapid maxillary expansion and protraction were performed using 3D-printed mini-plates for anchorage. The mini-plates exhibited better adaptation to the bone contour, and titanium screw implantation was safer because of the customized design. The orthopedic force applied to each mini-plate was approximately 400-500 g, and the plates remained stable during the maxillary protraction process, which exhibited efficacious orthopedic effects and significantly improved the facial profile and esthetics. In phase 2, fixed appliances were used for alignment and leveling of the maxillary and mandibular dentitions. The complete two-phase treatment lasted for 24 months. After 48 months of retention, the treatment outcomes remained stable.

• Archives of Craniofacial Surgery
• /
• v.19 no.2
• /
• pp.148-151
• /
• 2018

The nose is an important landmark of the face and its shape and beauty is of significant concern. The columella is the subunit between the two nostrils that provides support and projection to the nasal tip and has functional role in nostrils, as well as aesthetic. Ethiology for columellar absence or deficiency is diverse, and it is one of the most complex nasal subunits to reconstruct because of its narrow horizontal dimension, its tenuous vascularity and limited availability of adjacent tissue. We present a patient with columellar, membranous septum and upper lip defect, due to oncological resection. The lip reconstruction was designed using advancement of two upper lip edges with the technique of webster perialar/nasocheek advancement. However, the perialar/nasocheek tissue which is usually discarded was used as inferiorly based skin flaps to reconstruct the membranous septum, columellar skin and nasal vestibule lining. Rib cage cartilage graft was used as columellar strut for support. At 1-year follow-up, the patient has good nasal contour and projection. Scaring of the columella is very subtle. This is a versatile way for successful reconstruction of a columella and large central facial defect in one-stage operation. It is a method which provides very satisfactory aesthetic result with minimum patient morbidity and discomfort.