• Tribology and Lubricants
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• v.33 no.2
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• pp.59-64
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• 2017

This study investigates friction and wear characteristics of anodized aluminum (Al) alloy 6061 by using a reciprocating tribotester. The diameter and height of the specimen are 30 mm and 10 mm, respectively. The surface roughness of the mirrored-surface is approximately $0.01{\sim}0.02{\mu}m$, and it is used throughout the current study. As a result of anodizing, the depth and diameter of the nanopore are approximately $25{\mu}m$ and 30-40 nm, respectively. The testing conditions are as follows: loads of 1, 3, and 5 N; a frequency of 1 Hz; a stoke of 3 mm; and a duration of 1800 s. We use deionized water with a volume of approximately $25{\mu}l$, as the lubricant. Micro Vickers hardness measurements show that mirrored-surface specimens had lower hardness values than anodized specimens. Further, their coefficients of friction are lower than those of the anodized samples, and the width of their wear track increases with load, as expected. The anodized specimens' coefficients of friction increase with stable frictional behavior and exhibit insignificant load dependence. Further, we observe that the width of the wear track is less than that of the mirrored-surface specimens, and micro cracks are present near it. Moreover, the anodizing process increases the hardness of the samples, improving their wear resistance. These results indicate that nanoporous structures are not effective in lowering friction under the water-lubricated condition.

• Health Policy and Management
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• v.6 no.1
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• pp.110-143
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• 1996

The purpose of this study is to assess the extent of inequality in health outcomes and the distribution of health services according to health need under National Health Insurance System in Korea. For the empirical analysis, data were collected through an interview survey during one month of October, 1994. Interview were conducted with a total of 10, 875 of the employees and the self-employed selected through cluster, systematic sampling. The major findings of this research are as follows: 1. The analysis of the differentials in morbidity rates by socio-economic group showed that health inequality in the pro-higher groups existed in all self-reported morbidity indicators. 2. The findings of the conventional use measures showed that the lower socio-economic groups had more ambulatory and inpatient services than the higher groups. In contrast to the level of the medical care utilization, however, the higher socio-economic groups were more likely to use the high-quality source of care in terms of their treatment place compared to the lower groups. 3. By using the need-based use measures, the results were different from each use-disability ration indicator. Using the use-disability ration measured by physician visits per 100 restricted-activity days in the population, it was found that there was no evidence favoring the higher socio-economic groups. In contrast, the use-disability ration based on physician visits per a chronic patient in one year displayed that there was remarkable relative difference by income group as well as the evidence of the pro-higher income groups. 4. The results of logistic regression analysis and two-stage estimation method indicated that although the utilization is significantly affected by type and duration of insurance coverage, the use or nonuse of service and the volume of physician care consumed is determined by health need and demographic characteristics rater than economic status. In sum, these findings suggest that physician service is equitably distributed according to health need under national health insurance system in Korea. As there were some evidences of inequality including the differential in physician visits of chronic patients by income group, however, the government should strengthen the activities to guarantee the equity of health services utilization.

• Archives of Reconstructive Microsurgery
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• v.3 no.1
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• pp.64-71
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• 1994

The successful treatment of the extensively traumatized foot warrants reconstruction utilizing tissue that will provide adequate coverage, is resistant to infection, thin enough to conform to the contours of the foot as well as durable to constant frictional movement and weight bearing. Currently, free flaps offer the best means in achieving these difficult and sometimes contradictory goals. We treated twenty-one patients suffering from extensive soft tissue loss of the foot due to trauma, electric burn or postburn sequelae with free flaps. A fasciocutaneous, musculocutaneous or muscle flap with skin grafting was used based on the location, volume of tissue required, and the functional anatomical requirement of the injured region. The follow-up duration averaged twenty-nine months. From our group of patients, we believe that the muscle free flap with skin grafting offers the most favorable outcome.

• Archives of Plastic Surgery
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• v.36 no.2
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• pp.183-187
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• 2009

Purpose: Because of the volume of elective sterilizations performed in the world during the past decade, the vasectomy was a popular method for male sterilization in Korea and this, in turn, had been followed by an increase in the number of patient requiring vasectomy reversal with the high rate of subsequent divorce and remarriage. Recently, many authors have reported high success rates of vasovasostomy using microsurgical techniques and we performed modified two layer vasovasostomy with intravasal silicone tube to increase postoperative patency and pregnacy rate. Methods: Microscopic vasovasostomy was performed in 9 patients and their average age was $35.78{\pm}1.36years$(from 28 years to 44 years) from June 2006 to June 2008 at our department using modified two layer vasovasostomy with silicone tube insertion. Standard Guibor silicone tube, consisting of two 17.7 cm, 0.064 cm diameter, malleable, stainless steel probes connected by 29 cm of silicone tubing wedged onto disposable probes, were used in all cases. Results: Success rates were 88.8 % for patency and pregnancy 44.4 % for pregnancy in modified two layer vasovasostomy with silicone tube insertion. The patency rates were higher in cases of long postoperative day and in cases of short duration of vasectomy and vasovasostomy. Conclusion: We used a modified method to correspond the patency and pregnancy rate in microscopical modified two layer vasovasostomy using the intravasal silicone tube permanently. This method brings normal patency in microsurgical vasovasostomy because the silicone tube prevent obstruction of anastomosed site of the vas permanently.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.458-465
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• 2010

Hundreds of Steller sea lions, Eumetopias jubatus, migrate from Sakhalin and the northern Kuril Islands to Hokkaido every winter. During this migration, they may use their roaring sounds to navigate and to maintain their groups. We recorded the roars of wild Steller sea lions that had landed on reefs on the west coast of Hokkaido, and those of captive sea lions, while making video recordings. A total of 300 roars of wild sea lions and 870 roars of captive sea lions were sampled. The fundamental frequency ($F_0$), formant frequency ($F_1$), pulse repetition rate (PRR), and duration of syllables (T) were analyzed using a sonagraph. $F_0$, $F_1$, and PRR of the roars emitted by captive sea lions increased in the order male, female, and juvenile. By contrast, the $F_1$ of wild males was lower than that of females, while the $F_0$ and PRR of wild males and females did not differ statistically. Moreover, the $F_0$ and $F_1$ frequencies for captive sea lions were higher than those of wild sea lions, while PRR in captive sea lions was lower than in wild sea lions. Since there was a linear relationship between body length and the $F_0$ and $F_1$ frequencies in captive sea lions, the body length distribution of wild sea lions could be estimated from the $F_0$ and $F_1$ frequency distribution using a regression equation. These results roughly agree with the body length distribution derived from photographic geometry. As the volume of the oral cavity and the length of the vocal cords are generally proportional to body length, sampled roars can provide useful information about a population, such as the body length distribution and sex ratio.

• Clinical and Experimental Reproductive Medicine
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• v.43 no.4
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• pp.207-214
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• 2016

Objective: This study aimed to determine the threshold of $anti-M{\ddot{u}}llerian$ hormone (AMH) as predictor of follicular growth failure in polycystic ovary syndrome (PCOS) patients treated with clomiphene citrate (CC). Methods: Fifty female subjects with PCOS were recruited and divided into two groups based on successful and unsuccessful follicular growth. Related variables such as age, infertility duration, cigarette smoking, use of Moslem hijab, sunlight exposure, fiber intake, body mass index, waist circumference, AMH level, 25-hydroxy vitamin D level, and growth of dominant follicles were obtained, assessed, and statistically analyzed. Results: The AMH levels of patients with successful follicular growth were significantly lower (p= 0.001) than those with unsuccessful follicular growth ($6.10{\pm}3.52$ vs. $10.43{\pm}4.78ng/mL$). A higher volume of fiber intake was also observed in the successful follicular growth group compared to unsuccessful follicular growth group (p= 0.001). Our study found the probability of successful follicle growth was a function of AMH level and the amount of fiber intake, expressed as Y =-2.35+($-0.312{\times}AMH\;level$)+($0.464{\times}fiber\;intake$) (area under the curve, 0.88; 95% confidence interval, 0.79-0.98; p< 0.001). Conclusion: The optimal threshold of AMH level in predicting the failure of follicle growth in patients with PCOS treated with CC was 8.58 ng/mL.

• Safety and Health at Work
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• v.11 no.1
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• pp.109-117
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• 2020

Background: Ammonia and hydrogen sulfide are harmful gases generated during aerobic/anaerobic bacterial decomposition of livestock manure. We evaluated ammonia and hydrogen sulfide concentrations generated from workplaces at livestock farms and determined environmental factors influencing the gas concentrations. Methods: Five commercial swine farms and five poultry farms were selected for monitoring. Real-time monitors were used to measure the ammonia and hydrogen sulfide concentrations and environmental conditions during the manure-handling processes. Monitoring was conducted in the manure storage facility and composting facility. Information on the farm conditions was also collected through interview and walk-through survey. Results: The ammonia concentrations were significantly higher at the swine composting facilities (9.5-43.2 ppm) than at other manure-handling facilities at the swine and poultry farms, and high concentrations of hydrogen sulfide were identified during the manure agitation and mixing process at the swine manure storage facilities (6.9-19.5 ppm). At the poultry manure-handling facilities, the ammonia concentration was higher during the manure-handling processes (2.6-57.9 ppm), and very low hydrogen sulfide concentrations (0-3.4 ppm) were detected. The air temperature and relative humidity, volume of the facility, duration of manure storage, and the number of animals influenced the gas concentrations. Conclusion: A high level of hazardous gases was generated during manure handling, and some levels increased up to risk levels that can threaten workers' health and safety. Some of the farm operational factors were also found to influence the gas levels. By controlling and improving these factors, it would be possible to protect workers' safety and health from occupational risks.

• Journal of the Korean Dietetic Association
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• v.15 no.2
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• pp.168-178
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• 2009

Hematopoietic stem cell tranntation is being widely used in an attempt to treat many hematological diseases such as leukemia, anemia, and lymphoma. To evaluate the success of hematopoietic stem cell transplantation, it is very important to determine how rapidly engraftment occurs. Therefore, this retrospective study was conducted to determine which factors affected the term of engraftment during hematopoietic stem cell transplantation, while focusing on the oral intake status. To accomplish this, 416 patients who underwent transplant operations at St. Mary's hospital from May 2006 to April 2008 were evaluated. The long-term engraftment group was characterized as having longer fasting days and more frequent vomiting, diarrhea, and oral mucositis incidences than the short-term engraftment group. In addition, the inhibitors of oral intake such as vomiting, diarrhea, and oral mucositis developed frequently between the pre-transplantation and 2 weeks after transplantation. A significantly negative correlation was observed between the oral intake volume and the duration of the oral intake inhibitors. A multiple regression analysis revealed that the frequency of vomiting and oral mucositis during hematopoietic stem cell transplantation, the length of hospitalization, and the hematocrit level in the 2 weeks after hematopoietic stem cell transplantation were significant predictors of engraftment. The results of this study could be used to establish a guideline for nutritional assessment, nutritional goals, and nutritional support for patients during hematopoietic stem cell transplantation.

• Food Science of Animal Resources
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• v.40 no.5
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• pp.813-830
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• 2020

In this study, the potential of infrared assisted freeze-drying (IRAFD) was tested for the production of shelf-stable edible insects: Protaetia brevitarsis larva (larva of white-spotted flower chafer). The IRAFD system was customized using an infrared lamp, K-type thermocouple, controller, and data acquisition system. The infrared lamp provided the sublimation energy for rapid freeze-drying (FD). The IRAFD conditions were continuous IRAFD-5.0 kW/㎡ and IRAFD-5.0 kW/㎡ at different weight reduction (WR) (10%, 20%, and 30%). The continuous IRAFD reduced the drying time to 247 min compared to the 2,833 min duration of FD (p<0.05). The electrical energy could be reduced by more than 90% through infrared radiation during FD (p<0.05). The Page model resulted in the best prediction among the tested drying kinetic models. In terms of quality, IRAFD showed significantly lower hardness, chewiness, and higher protein levels than hot air drying and FD (p<0.05). IRAFD better preserved the glutamic acid (6.30-7.29 g/100 g) and proline (3.84-5.54 g/100 g). The external product appearance after IRAFD exhibited more air pockets and volume expansion, which might result in a good consumer appeal. In conclusion, this study reports the potential of IRAFD in producing shelf-stable and value-added edible insects.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.6
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• pp.60-65
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• 2004

Numerical simulations and experiments have been carried out to investigate the effect of fuel injection nozzles on the combustion and NOx formation processes in a medium-speed marine diesel engine. Spray visualization experiment was performed in the constant-volume high-pressure chamber to verify the numerical results on the spray characteristics such as spray angle and spray tip penetration. Time-resolved spray behaviors were captured by high-speed digital camera and analyzed to extract the information on the spray parameters. Spray and combustion phenomena were examined numerically using FIRE code. Wave breakup and Zeldovich models were adopted to describe the atomization characteristics and NOx formation processes. Numerical results were verified with experimental data such as cylinder pressure, heat release rate and NOx emission. Finally, the effects of fuel injection nozzles on the engine performance were investigated numerically to find the optimum nozzle parameters such as fuel injection angle, nozzle hole diameter and number of nozzle holes. From this study, the optimum fuel injection nozzle (nozzle hole diameter, 0.32 mm, number of nozzle holes, 8 and fuel injection angle, $148^{\circ}$) was selected to reduce both the fuel consumption and NOx emission. The reason for this selection could be explained from the highest fuel-air mixing in the early phase of injection due to the longest spray tip penetration and the highest heat release rate after $19^{\circ}$ ATDC due to the increased injection duration.