• Journal of the Korean institute of surface engineering
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• v.29 no.4
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• pp.268-277
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• 1996

Boronizing treatment of Microalloyed steel has been investigated by mean of Boronizing paste mainly consisted of $B_4C$ at various temperatures and times. The micro hardness of the boride layers were about HV 1200~1500. The thickness of the boride layer were increased with an increase of square root of treatment time at constant temperature. The activation energy for diffusion of boron in the specimen obtained from the slope of Arrhenius plots was 254 kJ/mol, but 197 kJ/mol for the induction heated specimen. The boride layer had a good corrosion resistance in solutions of 20% HCl and 20% $H_2SO_4$, solution. In 20% $HNO_3$ solution, however, its corrosion resistance increased. The boride layer had a good high temperature oxidation resistance at below $800^{\circ}C$, but at temperature above $900^{\circ}C$, the oxidation resistance decreased as the oxidation temperature.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.9
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• pp.930-937
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• 2009

The estimation method of the fracture resistance curve for the pipe specimen was proposed using the load ratio method for the standard specimen. For this, the calculation method of the load - CMOD curve for the pipe specimen with the common format equation(CFE) was proposed by using data of the CT specimen. The proposed method agreed well with experimental data. The J-integral value and the crack extension were calculated from the estimated load - CMOD data. The fracture resistance curve was estimated from the calculated J-integral and the crack extension. From these results, it have been seen that the proposed method is reliable to estimate the J-R curve of the pipe specimen.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.4
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• pp.565-572
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• 1996

The purpose of this study was to measure partial heat resistance of Hanbok when it worn. Since Hanbok varies from season to season, four different set of Hanboks (R, SN, p and S) were tested. Also Durumagi (D) which is worn over Hanbok (5) to keep warm from winter cold was tested as well. The thermal manikin was used in this experiment. The room temperature, air velocity and the relative humidity was set at $20\pm0.5^{\circ}C$, 0.15 m/sec and $50\pm$5% respectively. The mean skin temperature of the manikin was set at $33\pm0.5^{\circ}C$. The results were as follows: 1. The order from the least total heat resistance to the most was SN, R, p, 5 and D. 2. Upper arms had the highest heat resistance among the 13 parts. The next was abdomen thighs, buttock, legs, forearms and chest, back, and head, the order from the most to the least.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.11
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• pp.1174-1177
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• 2012

In voltage measurement by using voltage divider with series resistors, error is generated caused by the variation of resistance. In order to reduce these errors, the hardware cost tends to increase in the previous works. In the proposed method, three resistors are used for the voltage divider of which the organization is adjusted by using switches. Three voltages are measured and the ratio of resistance is calculated based on the measured voltages. Since the resistance ratio is calculated by measuring voltages and additional hardware cost is minimal, the voltage can be measured with high accuracy and low cost. Experimental results show that the mean absolute error is 12.1 mV when the input voltage ranges from 5 V to 50 V.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.1
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• pp.53-60
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• 1992

In this study, cathodic protection experiment was carried out by Al-alloy sacrificial anode in marine environments which have specific resistance($\rho$) if 25~7000$\Omega$.cm and investigated protection potential, current density and loss rate of Al-alloy sacrificial anode. The main results resistance($\rho$) of 400$\Omega$.cm, the cathodic protection potential appears high about-720 mV(SCE). But below specific resistance($\rho$) of 300$\Omega$.cm, the cathodic protection potential appears low about-770 mV(SCE) and simultaneously, cathode is protected sufficiently. 2) The loss rate of Al-Alloy sacrificial anode became large with decreasing specific resistance and increasing the ratio(A sub(c)/A sub(a) of bared surface area of anode and cathode. 3) The loss rate of Al-alloy sacrificial anode(w) to the mean current density of anode(i) is as follows. w=ai+b (a, b : experimental constants)

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.14 no.1
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• pp.15-23
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• 2008

Purpose : To evaluate the effects of elastic resistance exercise of lumbo-pelvic region and upper limbs muscle on equilibrium ability and shoulder pain of the elderly. Methods : The subject consisted of sixteen healthy elderly people(14 females. 2 males). They were from 61 to 83 years old and the mean age was 68.06. All subjects were assigned only the elastic resistance exercise group. The subject group received elastic resistance exercise for about 60 minutes per day, two times per weeks, during 8 weeks period. A Stop watch was used to measure static equilibrium ability and dynamic equilibrium ability and then pressure algometer was used to measure shoulder press pain threshold. All measurements of each subjects were measured at pre-experiment and post-experiment stage. SPSS 12.0 program was used to compile results. A Paired samples t-test was conducted to examine changes of static equilibrium, dynamic equilibrium and shoulder press pain threshold between pre-experiment and post-experiment. Results : The static equilibrium ability, dynamic equilibrium ability and shoulder press pain threshold were significantly differences between pre-experiment and post-experiment(p<.05). Conclusion : This data suggests that an eight week elastic resistance exercise improved static equilibrium ability and dynamic equilibrium ability and then reduced shoulder pain.

• Clinical and Experimental Pediatrics
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• v.64 no.1
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• pp.12-20
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• 2021

The mean age at menarche (AAM) of Korean females has been rapidly decreasing over the last 50 years; currently, the prevalence of early menarche (<12 years) is 22.3%. Female adolescents who experience early menarche are known to be at greater risk of psychosocial and behavioral problems along with several physical health problems such as menstrual problems. They also tend to achieve a shorter final height and develop obesity. Population-based Korean studies have shown a strong association between early menarche and the risk of obesity, insulin resistance, metabolic syndrome, nonalcoholic fatty liver disease, diabetes, breast cancer, and cardiovascular disease in adulthood. Although the exact mechanism of how early menarche causes cardiometabolic derangement in later adulthood is unknown, childhood obesity and insulin resistance might be major contributors. Recent studies demonstrated that an excessive consumption of fructose might underlie the development of obesity and insulin resistance along with an earlier AAM. A positive association was observed between sugar-sweetened beverages (a major source of fructose) intake and obesity, metabolic syndrome, insulin resistance, and cardiometabolic risk in Korean females. In pediatrics, establishing risk factors is important in preventing disease in later life. In this regard, early menarche is a simple and good marker for the management of cardiometabolic diseases in adulthood. Decreasing one's fructose intake might prevent early menarche as well as the development of obesity, insulin resistance, and cardiometabolic diseases.

• Proceedings of the Korea Water Resources Association Conference
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• 1982.07a
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• pp.3-24
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• 1982

The relations between tidal fluctuation and freshwater discharge are stuied dy use of observed data in the estuarine region of the Nagdong Rivre. Damping modulus which represents the resistance to propagation of tidal wave is estimated, and it is verified that when the fresh water discharge is lower than 300 m/sec., the elevation of mean-water-level at Gupo is the same as mean sea-water-level.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.4
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• pp.32-42
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• 2007

The substrate resistance is modeled to estimate the performance degradation of analog circuits by substrate noise in a $0.35{\mu}m$ twin-well non-epitaxial CMOS process. The substrate resistance model equations are applied to the P+ guard-ring isolation structure and a good match was achieved between measurements and models. The substrate resistance is divided into four types and a semi-empirical model equation is obtained for each type of substrate resistance. The rms(root-mean-square) error of the substrate resistance model is below 10% compared with the measured resistance. To apply this substrate resistance model to the P+ guard ring structure, ADS(Advanced Design System) circuit simulation results are compared with the measurement results using Network Analyzer, and relatively good agreements are obtained between measurements and simulations.

• Journal of Life Science
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• v.19 no.5
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• pp.625-632
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• 2009

The purpose of this study was to examine the effect of exercise training on nitric oxide (NO) levels, mean arterial pressure (MAP), blood pressure (BP), and heart rate (HR) in college students. 5 subjects were randomly assigned to two experimental groups; an aerobic training group (ATG) and a resistance training group (RTG). In aerobic training, based on measured maximum oxygen consumption rate, 70% exercise intensity was applied and conducted for 60 min. In resistance training, 70% of 1-RM was performed for 90 min. Blood sampling was conducted 3 times during resting state, post-exercise, and after 30 minutes of recovery. The results are as followed. For the post training values of $VO_2max$, % body fat and MAP, there were significant differences in the ATG compared to pre training (p<0.05). However, there were no differences in the RTG between pre and post training. NO increased post training, during rest and at the end of exercise compared to pre training in the ATG (p<0.05). Also, the HR decreased in post training at the end of exercise (p<0.05), however, there were no significant differences in SBP and DBP between pre and post training in the ATG. The HR, SBP and DBP did not change at all in post training compared to pre training in the RTG. In conclusion, an increase in the production of Nitric Oxide (NO) concentration and $VO_2max$, decrease of body fat% and physiological variables (HR, BP, MAP) were shown to be more effective in aerobic training (AT) than resistance training (RT).