• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.8
• /
• pp.91-98
• /
• 1999

This paper describes the air flow characteristics inside the throttle valve. Tow-dimensional steady incompressible Navier-Strokes equation are solved numerically with embedding the conceopt of the artificial compressibility and adopting the Baldwin-Lomax turbulence model. With varying the valve opening angles(the Reynolds number )such as 15$^{\circ}$(5000) , 45$^{\circ}$(3000) , 75$^{\circ}$(7000) and 90$^{\circ}$(10000), respectively. tow cases, with a valve shaft and without one, are analysed. The pressure loss between the entrance and exit is severe at 15$^{\circ}$, 100 times as larger as that of 90$^{\circ}$ case, which also depends much on the existece of the valve shaft. The counter rotating vortices are formed over the valve plate with the shaft at only 75$^{\circ}$. They are smally and very large scale in front and back of the valve shaft , respectively. The velocity profiles of 15$^{\circ}$ and 90$^{\circ}$ at the exit are almost symmetric to the horizontal center line, however, the symmetricity is no longer maintained at 45$^{\circ}$ and 75$^{\circ}$ , and in addition, the flow at 75$^{\circ}$ is enforced a lot below center line. The pressure distribution on the walls is largely changed near the valve shaft, and its magnitude becomes great as the valve angle decreases.

• Archives of Reconstructive Microsurgery
• /
• v.22 no.1
• /
• pp.33-37
• /
• 2013

Purpose: The concept and development of perforator free flaps have led to significant advances in microsurgery. Ongoing developments in perforator free flap surgery are aimed at reducing complications and improving surgical outcomes. The aim of this study was to evaluate the effectiveness and application of supermicrosurgery in free flap surgery. Materials and Methods: A total of 267 patients with soft tissue defects of the lower extremity due to various etiologies from January, 2007 to January, 2013. The patients received either an anterolateral thigh free flap (n=83), a superficial circumflex iliac artery free flap (n=152), an upper medial thigh free flap (n=19), or a superior gluteal artery perforator free flap (n=13). Microanastomosis was performed using a perforator-to-perforator technique, either end-to-end or end-to-side. Results: The mean postoperative follow up period was eight months (range: one to 16 months) and flap loss occurred in 11 cases out of 267. All cases of flap loss occurred within two weeks of surgery due to either arterial insufficiency (n=5) or venous congestion (n=6). Conclusion: Supermicrosurgery enables the selection of the most efficient perforator for microanastomosis at the defect site. It also reduces the time required for dissection of recipient vessels, and reduces the possibility of injury to major vessels. Microsurgery using a vessel of less than 1 mm has been reported to increase the risk of flap failure; however, using the most advanced surgical tools and developing experience in the technique can produce success rates similar to those found in the literature.

• Journal of Korean Medicine for Obesity Research
• /
• v.14 no.1
• /
• pp.29-35
• /
• 2014

Objectives: This study was to investigate how body-shape perception could influence to weight control practice both in normal and obese group. Methods: We used 2012 Korea National Health and Nutrition Examination Survey to analysis 1) weight control practices of population; 2) consistency between body-shape perception and body mass index; 3) comparison weight control practices between normal group and body mass index (BMI) obese group in perceptional obese group; 4) odds ratio of BMI obese group using herbal drugs for weight control practice in perceptional obese group. Results: We found that study population tends to choose exercise, dietary restriction, meal skip, health functional food, one-food, drug, herbal drug, fasting and self-medication in order of frequency to control weight. The agreement between body-shape perception and BMI within obese group was approximately 64% with 0.40 of Cohen's Kappa coefficient, ranging from 0.384 to 0.423. Within perceptional obese group, choosing each weight control practice methods ratios between normal BMI group and obese BMI group were not significantly different. Within perceptional obese group, obese BMI group showed significant odds ratio (2.58, 95% confidence intervals, 1.38~4.85) than normal BMI group in choosing herbal medication for weight loss when adjusting other variables. Conclusions: We concluded that body-shape perception might be an important factor for choosing weight control program, and roles of Korean medical doctors thought to be enhanced for using herbal medication for weight loss.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.11 no.2
• /
• pp.883-898
• /
• 2019

This paper employs computational tools to predict power increase (or speed loss) and propulsion performances in waves of KVLCC2. Two-phase unsteady Reynolds averaged Navier-Stokes equations have been solved using finite volume method; and a realizable k-ε model has been applied for the turbulent closure. The free-surface is obtained by solving a VOF equation. Sliding mesh method is applied to simulate the flow around an operating propeller. Towing and self-propulsion computations in calm water are carried out to obtain the towing force, propeller rotating speed, thrust and torque at the self-propulsion point. Towing computations in waves are performed to obtain the added resistance. The regular short head waves of λ/LPP = 0.6 with 4 wave steepness of H/λ = 0.007, 0.017, 0.023 and 0.033 are taken into account. Four methods to predict speed-power relationship in waves are discussed; Taylor expansion, direct powering, load variation, resistance and thrust identity methods. In the load variation method, the revised ITTC-78 method based on the 'thrust identity' is utilized to predict propulsive performances in full scale. The propulsion performances in waves including propeller rotating speed, thrust, torque, thrust deduction and wake fraction, propeller advance coefficient, hull, propeller open water, relative rotative and propulsive efficiencies, and delivered power are investigated.

• Korean Journal of Optics and Photonics
• /
• v.19 no.1
• /
• pp.31-35
• /
• 2008

A rod-type aspheric lens collimator for the optical telecommunication system which shows high coupling efficiency and experiences small coupling loss for misalignment errors is designed. The working distance, thickness, and diameter of the rod-type aspheric lens are determined to be close to those of the GRIN lens collimator in order to replace the GRIN lens with the rod-type aspheric lens. Since the coupling loss mainly originated from the spherical aberration of the lens, the spherical aberration in the rod-type aspheric lens is reduced drastically, and it turns out that the coupling efficiency of the rod-type aspheric lens collimator is higher than that of the available collimators, such as ball lens, GRIN lens, and C-type lens collimators.

• Food Science of Animal Resources
• /
• v.33 no.4
• /
• pp.456-462
• /
• 2013

The present study investigated the effects of Liriopeplatyphylla extract (LPE) and Akebiaquinata extract (AQE) on breast meat properties when used as dietary supplements of broiler chickens. First, the identification and quantification of phenolic acids and flavonoids were carried out by HPLC. As a result, the total amount of phenolic acids and flavonoids was higher in AQE than LPE. These extracts were added at a rate of 0.2% to the broiler diets, and a feeding trial was conducted in battery cages for 35 d. At the end of the experiment (d 35), six carcasses from each treatments were used for evaluating meat quality. The experimental results indicate that color shades, pH levels, volatile basic nitrogen, thiobarbituric acid reactive substance (TBARS), cooking loss and drip loss of breast meat fed with 2 extracts were not different as compared with the controls at d 0 and d 10 of storage. However, TBARS values of breast meat fed with either the control diet or the LPE supplementation was increased as the storage period increased (from d 0 to d 10) (p<0.05), while AQE-fed groups were not different between d 0 to d 10 of storage. In textural properties, the addition of LPE and AQE decreased shear force values at d 10 of storage (p<0.05). Cohesiveness, gumminess and chewiness of breast meat were increased in AQE-fed groups when compared with the control at d 0 of storage (p<0.05). Dietary additions of AQE and LPE only increased the linoleic acid contents of chicken breast meat (p<0.05). In conclusion, supplementation of these extracts in broiler diets may potentially influence meat qualities including the TBARS, textural properties and linoleic acid levels in broiler chicken meats.

• Journal of Periodontal and Implant Science
• /
• v.42 no.6
• /
• pp.212-216
• /
• 2012

Purpose: The aim of this study was to evaluate the relationship between maternal periodontal disease and the health status of newborns using Apgar scores. Methods: One hundred pregnant women with periodontal disease were included in the case series and 100 pregnant women without periodontal disease were placed in the control group, respectively. The periodontal parameters of bleeding on probing (BOP), clinical attachment loss (CAL), probing depth (PD), birth weight, and Apgar scores were recorded in both groups. T-tests and Pearson's correlation coefficient were used to determine the birth weight odds ratio to analyze the relationship between the periodontal parameters of BOP, CAL, and PD on the one hand and an Apgar score of less than 7. An unpaired Student's t-test was used to analyze differences in means between the case and control groups using SPSS ver. 13. Results: The means of the ages, periodontal pocket depths, attachment loss, areas with BOP, Apgar score in the first 5 minutes and infant birth weight exhibited statistically significant differences between the case and control groups. The ratio of an Apgar score of <7 to periodontal disease was 3.14; the ratio of low birth weight risk in mothers with periodontal disease to that in mothers without periodontal disease was 2.74. Pearson's correlation coefficient revealed a significant correlation between the infant birth weight and BOP, CAL, and PD of the mother. In addition, there was a significant correlation between the Apgar score and BOP, CAL, and PD and also between the Apgar score and infant birth weight. Conclusions: The results of this study showed a significant relationship between periodontal disease and infant birth weight; in addition, there was a significant relationship between the periodontal indexes of BOP, CAL, and PD on the one hand and the Apgar score on the other.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.54 no.6
• /
• pp.25-29
• /
• 2017

This paper presents a hetero-integration of electrostatically actuated RF MEMS Switch and step up DC-DC converter on a redistribution layer using commercial PCB process. RF characteristics of Duroid with $56{\Omega}$ impedance GCPW transmission line and that of FR4 with $59{\Omega}$ impedance CPW transmission line were analyzed. From DC to 6GHz, RF characteristics of Duroid were better than that of FR4, insertion loss was 2.08dB lower, return loss was 3.91dB higher, and isolation was 3.33dB higher.

• Child Health Nursing Research
• /
• v.6 no.3
• /
• pp.397-410
• /
• 2000

This is a nonequivalent control group pretest- posttest design in quasi experimental basis to assess how the thermal head and feet support influences on early stage weight gain in premature neonates. The clients were selected among the premature infants with the weight under 2000gms and with the gestational period under 37 weeks, admitted over 15 days in K university hospital, Seoul. The control group of 29 were selected from January 1998 to August 1998, who were without head and feet thermal support, and the experimental group of 30 were selected from September 1998 to May 1999, who were with the two thermal interventions. The results of the study follow, 1.The experimental group with thermal interventions showed more weight gain than the control group without thermal interven- tions, which was statistically significant between the two groups. 2.The physiological weight loss after birth showed less in the experimental group than in the control group. 3.The recovery of the birth weight after the physiologic weight loss showed no statistical difference between the experimental group and the control group. Consequently, the thermal head and feet supportive nursing intervention could be applied as a nursing intervention program to help the premature neonates' development. With the results above we should like to suggest the following: 1) A continuous application in the practice of our thermal supportive intervention for the premature neonates, a development of the content through evaluation, and a comparision of the results through a long time study. 2) A neccessity of deveopment of various study and cross comparision. 3) A neccessity of multi-angular study on the premature infants' characteristics influencing the thermal therapy and the study of the individual differences of the clients.

• Korean Journal of Computational Design and Engineering
• /
• v.22 no.2
• /
• pp.141-149
• /
• 2017

Vulnerability assesses the loss of major performance functions of GCV (Ground Combat Vehicles) when it is hit by enemy's shell. To decide the loss of major functions, it is determined what effects are on the performance of GCV when some components of GCV are failed. M&S (Modeling and Simulation) technology is used to vulnerability assessment. The hydro-pneumatic suspension is used as a sample part. The procedures of vulnerability assessment of the hydro-pneumatic suspension are shown as follows: 1) The components of the suspension are defined, and shot lines are generated evenly around the part. 2) The penetrated components are checked by using the penetration equation. 3) The function model of the suspension is designed by using IDEF0. 4) When the failure of the critical components of the suspension happens, its effect on the function of the suspension can be estimated using DMEA (Damage Mode and Effects Analysis). 5) The diagram of FTA (Fault Tree Analysis) is designed by exploiting DMEA. 6) The damage probability of the suspension is calculated by using FTA and vulnerable area method. In this paper, SLAP (Shot Line Analysis Program) which was developed based on COVART methodology. SLAP calculates the damage probability and visualizes the vulnerable areas of the suspension.