• Journal of Powder Materials
• /
• v.24 no.3
• /
• pp.216-222
• /
• 2017

Synthesized monocrystalline nanodiamond (nD) particles are heat-treated at various temperatures to produce highly structured diamond crystals. The heat-treated nDs show different weight loss ratios during thermogravimetric analysis. The crystallinities of the heat-treated nDs are analyzed using Raman spectroscopy. The average particle sizes of the heat-treated nDs are measured by a dynamic light scattering (DLS) system and direct imaging observation methods. Moreover, individual dispersion behaviors of the heat-treated nD particles are investigated based on ultrasonic dispersion methods. The average particle sizes of the dispersed nDs according to the two different measurement methods show very similar size distributions. Thus, it is possible to produce highly crystallized nD powder particles by a heat-treatment process, and the nD particles are relatively easy to disperse individually without any dispersant. The heat-treated nDs can lead to potential applications such as in nanocomposites, quantum dots, and biomedical materials.

• Journal of Nutrition and Health
• /
• v.28 no.5
• /
• pp.451-459
• /
• 1995

This study was intended to figure out the effects of the amount and the distribution of body fat on the risk fators of adult disease. Sixty-four male college students paticipatied in this study, whose to find out body fat distributions were classified on the basis of Waist/hip ratio(WHR) into three groups-upper body type(UBTM), intermediate body type (IBTM) and lower body type(LBTM). Various risk factors such as adiposity, body fat ammount, serum lipid amount and blood pressure and their intercorrelations were analyzed. The three bodys type groups showed significant differences each other in weight(P<0.001), WHR showed considerable correlations with BMI and the percentage of body fat. The frequency of obesity assessed by BMI$\geq$25 and body fat percentage were the highest in the UBTM of the three groups. Thus, we could conclude that the closer the body fat distribution is to the upper body type, the higher the BMI and body fat percentage. Waist/girth ratio(WTR, P<0.01) and BMI(P<0.05) were positively correlated with serum triglyceride levels, and % of body fat was positively correlated with both serum triglyceride (P<0.01) and serum total cholesterol(P<0.05) levels. WHR (P<0.05), BMI(P<0.01) and % of body fat(P<0.01) also showed positive correlations with systolic blood pressure. From the above results, we could conclude that body fat distribution was a good index reflecting adiposity and body fat amount and that blood and serum amount of triglyceride was highest in the upper body type group showing the highest frequency of obesity.

• Journal of the Ergonomics Society of Korea
• /
• v.24 no.4
• /
• pp.23-30
• /
• 2005

The mailman's shoes should be designed in due consideration of occupational features they spend most of times to walk. For that reason, the shoes required functions to reduce the foot fatigue and to protect body by dispersing the body weight to the whole foot. In this research, for the functional improvement of the insole, insoles are investigated and analyzed by biomechanics experimentation. Under the base of these experimental results, we develop insoles that can reduce the body load and muscular-skeletal disorder. The pressures are concentrated on the metatarsus and heel by the result of analyzing pressure distributions of the using shoes. Accordingly, we offer the prototype functional insole that is ranked from high pressure to low pressure on the base of a shock absorb function. This prototype functional insole is examined for statistical significance by pressure distribution areas. The experimental results show that pressure areas are dispersed to whole foot, for this reason, pressures of the metatarsus and heel are reduced. Results of this research can not only improve the function of insoles which is suitable for occupational features, but also be a base on constructing data bases for biomechanics gait insoles.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.9
• /
• pp.942-949
• /
• 2014

In this paper, a new steering system for a self-balancing electric scooter is proposed with an intuitive steering command input method, where the steering command is generated from the rider's motion of shifting body to move the center of gravity toward the rotational direction. For the purpose, weight distributions on the rider's feet are measured using force sensors placed beneath the rider's feet, and the difference is applied to a steering control system. Stability of the steering system and resultant radius of gyration is investigated by modeling the steering system in consideration of the rider's motion and centrifugal force. The proposed steering system is applied to experiments, and the results are presented to prove the validity of the proposed method.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.247-254
• /
• 2000

The base pressure of vacuum vessel of the KSTAR (Korea Superconducting Tokamak Advanced Research) Tokamak is to be a ultra high vacuum, $10^{-6}{\sim}10^{-7}Pa$, to produce clean plasma with low impurity containments. For this purpose, the KSTAR vacuum vessel and plasma facing components need to be baked up to at least $250^{\circ}C,\;350^{\circ}C$ respectively, within 24 hours by hot nitrogen gas from a separate baking/cooling line system to remove impurities from the plasma-material interaction surfaces before plasma operation. Here by applying the implicit numerical method to the heat balance equations of the system, overall temperature distributions of the KSTAR vacuum vessel and plasma facing components are obtained during the whole baking process. The model for 2-dimensional baking analysis are segmented into 9 imaginary sectors corresponding to each plasma facing component and has up-down symmetry. Under the resulting combined loads including dead weight, baking gas pressure, vacuum pressure and thermal loads, thermal stresses in the vacuum vessel during bakeout are calculated by using the ANSYS code. It is found that the vacuum vessel and its supports are structurally rigid based on the thermal stress analyses.

• Computers and Concrete
• /
• v.25 no.3
• /
• pp.215-224
• /
• 2020

In the present study, according to the important of porosity in low specific weight in comparison of high stiffness of carbon nanotubes reinforced composite, buckling and free vibration analysis of sandwich composite beam in two configurations, of laminates using differential quadrature method (DQM) is studied. Also, the effects of porosity coefficient and three types of porosity distribution on critical buckling load and natural frequency are discussed. It is shown the buckling loads and natural frequencies of laminate 1 are significantly larger than the results of laminate 2. When configuration 2 (the core is made of FRC) and laminate 1 ([0/90/0/45/90]_s) are used, the first natural frequency rises noticeably. It is also demonstrated that the influence of the core height in the case of lower carbon volume fractions is negligible. Even though, when volume fraction of fiber increases, the critical buckling load enhances smoothly. It should be noticed the amount of decline has inverse relationship with the beam aspect ratio. Investigating three porosity patterns, beam with the distribution of porosity Type 2 has the maximum critical buckling load and first natural frequency. Among three elastic foundations (constant, linear and parabolic), buckling load and natural frequency in linear variation has the least amount. For all kind of elastic foundations, when the porosity coefficient increases, critical buckling load and natural frequency decline significantly.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.12
• /
• pp.5965-5967
• /
• 2012

Cancer is now the main cause of increasing mortality throughout the world. Minor alterations in the cell cycle which are inherited and not removed by apoptosis are important rsik factors. Blood cancers are asmong the types which most readily cause death. Here in this study, usual but important factors such as age, gender, Rh and ABO blood typing, weight, and platelet counts are analyzed for impact on blood cancers. Frequencies and distributions, correlations and chi-square test were utilized in order to clarify the perspective of important factors. Our statistical results show males and females to have same risk in blood cancer but A blood type (40%) along with positive Rh (73%) had the highest risk. Low platelet counts are related to more than 80% of cases. Obesity has a statistically ignorable role in blood cancer prevalence. The fact that blood cancer cases increase during the second decade of life (45.7%) which might be because of involvement of maturation processes.

• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.12
• /
• pp.1327-1333
• /
• 2013

Air bearings are widely used in precision stages because of low friction and high motion accuracy, however, they suffer from low stiffness in comparison with rolling bearings or hydrostatic bearings. So, several preloading methods using weight, magnet and vacuum force, and opposing pads have been used to increase the stiffness of the air bearings. In this paper, pressure distributions of the vacuum preloaded porous air bearings are calculated using the proposed method. And then, the load capacity and stiffness are analyzed. For the vacuum preloaded air bearings, the stiffness is increased owing to reduced bearing clearance by vacuum force. The simulation results indicate that variation of vacuum pressure with clearance in the vacuum pocket gives rise to low stiffness, so the vacuum pocket should be designed for pressure to be constantly maintained regardless of the bearing clearance by means of large effective pumping speed.

• Korean Journal of Health Education and Promotion
• /
• v.29 no.5
• /
• pp.1-12
• /
• 2012

Objectives: Dietary modifications are common treatment strategies for adults with metabolic syndrome, but it is unclear how often these individuals read food labels. The objective of this study was to examine if adults with metabolic syndrome read food labels when buying packaged foods and to determine factors related to label use. Methods: From the database of the Fifth Korean National Health and Nutrition Examination Survey(KNHANES-V), 1,335 adults with metabolic syndrome and 3,696 those without were selected. Data were analyzed using frequency distributions, $X^2$ test and multiple logistic regression with the SPSS win 18.0 program. Results: Adults with metabolic syndrome read food labels less than individuals without it when they purchase packaged foods(12.5% vs 29.0%). Among those without metabolic syndrome, food label use was significantly higher among participants who were women, younger, educated, and trying to control weight. Conclusions: Strategies to use food label as a diet management tool for metabolic syndrome are needed.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.12
• /
• pp.1742-1746
• /
• 2014

In order to develop a overhead catenary system for the maximum speed of 400 km/h on Honam high-speed line, increasing tension of contact wire, changing dropper distributions, reducing a hard point and etc. should be considered. And it is also essential to develop core components taking account of the increased tension. Therefore we developed a new steady arm for the max. speed of 400 km/h in this study. FEM (Finite Elements Method) analysis was performed to ensure the strength of the arm. An oval shape was applied to the arm, so that 25 % of strength was increased and 9 % of weight was decreased. And a type test according to the code KRSA-3012 was performed to ensure the performance. Fatigue test in KRRI (Korea Railroad Research Institute)'s test-bed was also performed to evaluate its performance. Some section of the Honam High-speed line was constructed with the developed steady arm.