• Journal of Nutrition and Health
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• v.51 no.1
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• pp.103-119
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• 2018

Purpose: This study was implemented to develop and validate the semi-quantitative food frequency questionnaire (SQ-FFQ) to assess energy, carbohydrates, fat, protein, minerals, and vitamins as well as fatty acids and alcohol in Korean adults. Methods: The SQ-FFQ consisted of 88 food items, and 12 food groups were selected based on information of frequently consumed foods from the Korean Health and Nutrition Examination survey. Each portion size was categorized as one of three amounts: small (0.5 times), medium (1 time), and large (1.5 times). A total of 111 subjects finished 3-day diet records and the SQ-FFQ. The relative validity of SQ-FFQ was assessed by comparison with the 3-day diet records. Results: The mean nutrient intakes obtained from the SQ-FFQ were estimated to be greater than those of the two 3-day dietary records. Spearman's correlation coefficient between the two methods was the highest for energy (r = 0.583; p < 0.001) and lowest for saturated fatty acid (r = 0.121). Correlation coefficients were energy (r = 0.583; p < 0.001), carbohydrates (r = 0.500; p < 0.001), protein (r = 0.466; p < 0.001), fat (r = 0.411; p < 0.001), dietary fiber (r = 0.467; p < 0.001), alcohol (r = 0.527; p < 0.001), calcium (r = 0.409; p < 0.001), phosphorus (r = 0.499; p < 0.001), potassium (r = 0.418; p < 0.001), magnesium (r = 0.427; p < 0.001), and zinc (r = 0.464; p < 0.001), respectively, for all subjects. Conclusion: The developed SQ-FFQ in this study seems to be useful for estimating nutritional status, particularly energy, carbohydrates, protein, fat, dietary fiber, alcohol, calcium, phosphorus, potassium, magnesium, and zinc of Korean adults.

• Journal of dental hygiene science
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• v.12 no.6
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• pp.607-616
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• 2012

The purpose of this study was to examine the self-rated oral health status and oral health concern of 6,094 adults over the age of 19, which were both related to subjective oral health awareness, based on the second-year (2008) raw data of the 4th National Health and Nutrition Survey. 1. As for subjective oral health awareness, 49.4 percent replied they were in bad oral health when they were asked about self-rated oral health status. Regarding oral health concern, 62.6 percent answered they were sort of concerned about oral health. 2. As to oral health indexes by sociodemographic characteristics, there were statistically significant differences in oral health indexes according to gender, age, academic credential, monthly mean household income, frequency of eating between meals and toothbrushing frequency. Smoking made no statistically significant differences to oral health indexes (p<0.000). 3. Concerning self-rated oral health status by sociodemographic characteristics, no significant differences were found according to gender, age and academic credential, and there were statistically significant differences according to monthly mean household income and smoking (p<0.000), frequency of eating between meals (p<0.018), toothbrushing frequency (p<0.003). 4. In relation to oral health concern by sociodemographic characteristics, gender and smoking made no significant differences, and statistically significant differences were found according to age (p<0.003), academic credential, monthly mean household income, frequency of eating between meals and toothbrushing frequency (p<0.000). 5. In regard to the relationship between subjective oral health awareness and oral health indexes, none of the oral health indexes had a significant relationship to self-rated oral health status, and there were statistically significant differences in oral health concern according to functioning teeth index (p<0.011) and community periodontal index (p<0.017).

• Journal of the Korean Geotechnical Society
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• v.37 no.3
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• pp.19-30
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• 2021

The presence of the hydrate-bearing sediments in Ulleung Basin of South Korea has been confirmed from previous studies. Researches on gas production methods from the hydrate-bearing sediments have been conducted worldwide. As production mechanism is a complex phenomenon in which thermal, hydraulic, and mechanical phenomena occur simultaneously, it is difficult to accurately conduct the productivity and stability analysis of hydrate bearing sediments through lab-scale experiments. Thus, the importance of numerical analysis in evaluating gas productivity and stability of hydrate-bearing sediments has been emphasized. In this study, the numerical parametric analysis was conducted to investigate the effects of the bottom hole pressure and the depressurization rate on the gas productivity and stability of hydrate-bearing sediments during the depressurization method. The numerical analysis results confirmed that as the bottom hole pressure decreases, the productivity increases and the stability of sediments deteriorates. Meanwhile, it was shown that the depressurization rate did not largely affect the productivity and stability of the hydrate-bearing sediments. In addition, sensitivity analysis for gas productivity and stability of the sediments were conducted according to the depressurization rate in order to establish a production strategy that prevents sand production during gas production. As a result of the analysis, it was confirmed that controlling the depressurization rate from a low value to a high value is effective in securing the stability. Moreover, during gas production, the subsidence of sediments occurred near the production well, and ground heave occurred at the bottom of the production well due to the pressure gradient. From these results, it was concluded that both the productivity and stability analyses should be conducted in order to determine the bottom hole pressure when producing gas using the depressurization method. Additionally, the stress analysis of the production well, which is induced by the vertical displacements of sediments, should be evaluated.

• The Southeast Asian review
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• v.28 no.3
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• pp.213-261
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• 2018

On May 9, 2018, regime change took place in Malaysia. It was the first regime change that took place in 61 years after independence in 1957. The regime change was an unexpected result not only in Malaysian experts but also in political circles. Moreover, the outcome of the election was more shocking because the opposition party was divided in this general election. The regime change in Malaysia was enough to attract worldwide attention because it meant the collapse of the oldest regime in the modern political system that exists, except North Korea and China. How could this have happened? In particular, how could the regime change, which had not been accomplished despite opposition parties' cooperation for almost 20 years, could be achieved with the divided opposition forces? What political implications does the 2018 general election result have for political change and democratization in Malaysia? How will the Malaysian politics be developed in the aftermath of the regime change? It is worth noting that during the process of finding answers, a series of general elections since the start of reformasi in 1998 tended to be likened to a series of "tsunami" in the Malaysian electoral history. This phenomenon of tsunami means that, even though very few predicted the possibility of regime change among academia, civil society and political circles, the regime change was not sudden. In other words, the regime in 2018 was the result of the desire and expectation of political change through a series of elections of Malaysian voters last 20 years. In this context, this study, in analyzing the results of the election in 2018, shows that the activation of electoral politics triggered by the reform movement in 1998, along with the specific situational factors in 2018, could lead to collapse of the ruling government for the first time since independence.

• (The)Study of the Eastern Classic
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• no.71
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• pp.99-128
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• 2018

Zhōuyì周易 is intended to explain the affairs of human beings by observing the images and works of all things in the universe, abstracting them into the $b{\bar{a}}gu{\grave{a}}$八卦, calculating the process and inducing the outcome by the method of stalk divination, in which this paper finds the origin of natural scientific thought of Zhōuyì. The way of Zhōuyì's thought on the natural science is distinguished from that of the Western's. In the West, people dismantled the objects into the parts until they reached the atom and analyzed them by the principle of causality to draw an axiomatic truth. In the meantime Zhōuyì observed and studied the dynamic functions and changes of all things for the convergence of the whole. While the way of Zhōuyì's thinking could have not contributed to the development of modern scientific development, that of the West overwhelmed Asian development passing through the period of enlightenment during 16-17 century. This paper tries to articulate the points where Zhōuyì can share its theory with the contemporary science by finding the traces of scientific thoughts in Zhōuyì. It encounters its ground from the methodology of natural science and scientific statements proposed by Zhōuyì. The essential concepts of Zhōuyì are induced from all things in nature. This can be considered as the idea of '法自然'(emulating the patterns and examples from nature). Also they observed the images and changes seen by the habits of animals, plants and human beings to sense and perceive their laws. These are regarded as the methodology of natural science in Zhōuyì. As a book of divination, the way of stalk divination is designed to calculate the future by using the system of 'numbers'. 'tàijí太極', ' yīnyáng陰陽', 'four symbols四象', '$b{\bar{a}}gu{\grave{a}}$八卦' and 'wǔxíng五行' are the essential concepts of Zhōuyì to represents the dynamic phenomena and changes of the natural order. Among them '$b{\bar{a}}gu{\grave{a}}$八卦' is a presentment to explain the structure of the world not by the individual analysis of things but by the unification of the whole through the contradictions and interchanges among them to reach the new orders. As of now, the studies of Zhōuyì in Korea have focused on the traditional perspectives, such as political and ethical philosophy. Some of recent studies, having interpreted Zhōuyì with scientific inclination have generated controversy 'Can Zhōuyì be a science?', for which scholars have hard time to reach the agreement. This paper tries to find the headwaters of the contemporary natural science by elaborating the methodology of natural science stated in Zhōuyì.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.1
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• pp.39-46
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• 2021

The quantitative measurement of interfacial adhesion energy (Gc) of multilayer thin films for Cu interconnects was investigated using a double cantilever beam (DCB) and 4-point bending (4-PB) test. In the case of a sample with Ta diffusion barrier applied, all Gc values measured by the DCB and 4-PB tests were higher than 5 J/㎡, which is the minimum criterion for Cu/low-k integration without delamination. However, in the case of the Ta/Cu sample, measured Gc value of the DCB test was lower than 5 J/㎡. All Gc values measured by the 4-PB test were higher than those of the DCB test. Measured Gc values increase with increasing phase angle, that is, 4-PB test higher than DCB test due to increasing plastic energy dissipation and roughness-related shielding effects, which matches well interfacial fracture mechanics theory. As a result of the 4-PB test, Ta/Cu and Cu/Ta interfaces measured Gc values were higher than 5 J/㎡, suggesting that Ta is considered to be applicable as a diffusion barrier and a capping layer for Cu interconnects. The 4-PB test method is recommended for quantitative adhesion energy measurement of the Cu interconnect interface because the thermal stress due to the difference in coefficient of thermal expansion and the delamination due to chemical mechanical polishing have a large effect of the mixing mode including shear stress.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.86-92
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• 2022

Recently, the bio-healthcare market is enlarging worldwide due to various reasons such as the COVID-19 pandemic. Among them, biometric measurement and analysis technology are expected to bring about future technological innovation and socio-economic ripple effect. Existing systems require a large-capacity battery to drive signal processing, wireless transmission part, and an operating system in the process. However, due to the limitation of the battery capacity, it causes a spatio-temporal limitation on the use of the device. This limitation can act as a cause for the disconnection of data required for the user's health care monitoring, so it is one of the major obstacles of the health care device. In this study, we report the concept of a standalone healthcare monitoring module, which is based on both triboelectric effects and electromagnetic effects, by converting biomechanical energy into suitable electric energy. The proposed system can be operated independently without an external power source. In particular, the wireless foot pressure measurement monitoring system, which is rationally designed triboelectric sensor (TES), can recognize the user's walking habits through foot pressure measurement. By applying the triboelectric effects to the contact-separation behavior that occurs during walking, an effective foot pressure sensor was made, the performance of the sensor was verified through an electrical output signal according to the pressure, and its dynamic behavior is measured through a signal processing circuit using a capacitor. In addition, the biomechanical energy dissipated during walking is harvested as electrical energy by using the electromagnetic induction effect to be used as a power source for wireless transmission and signal processing. Therefore, the proposed system has a great potential to reduce the inconvenience of charging caused by limited battery capacity and to overcome the problem of data disconnection.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.243-248
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• 2022

As the scope of use of portable and wearable electronic devices is expanding, the limitations of heavy and bulky solid-state batteries are being revealed. Given that, it is urgent to develop a small energy harvesting device that can partially share the role of a battery and the utilization of energy sources that are thrown away in daily life is becoming more important. Contact electrification, which generates electricity based on the coupling of the triboelectric effect and electrical induction when the two material surfaces are in contact and separated, can effectively harvest the physical and mechanical energy sources existing in the surrounding environment without going through a complicated intermediate process. Recently, the interest in the harvest and utilization of wind energy is growing since the wind is an infinitely ecofriendly energy source among the various environmental energy sources that exist in human surroundings. In this study, the optimization of the energy harvesting device for the effective harvest of wind energy based on the contact electrification was analyzed and then, the utilization strategy to maximize the utilization of the generated electricity was investigated. Natural wind based Fluttering TENG (NF-TENG) using fluttering film was developed, and design optimization was conducted. Moreover, the safe high voltage generation system was developed and a plan for application in the field requiring high voltage was proposed by highlighting the unique characteristics of TENG that generates low current and high voltage. In this respect, the result of this study demonstrates that a portable energy harvesting device based on the contact electrification shows great potential as a strategy to harvest wind energy thrown away in daily life and use it widely in fields requiring high voltage.

• Journal of the Korean Orthopaedic Association
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• v.55 no.5
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• pp.405-410
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• 2020

Purpose: Pedicle screw insertion has been traditionally used as a surgical treatment for degenerative lumbar spine disease. As an alternative, the cortical-bone trajectory screw allows less invasive posterior lumbar fixation and excellent mechanical stability, as reported in several biomechanical studies. This study evaluated the clinical and radiological results of a case of early failure of cortical-bone screw fixation in posterior fixation and union after posterior decompression. Materials and Methods: This study examined 311 patients who underwent surgical treatment from 2013 to 2018 using cortical orbital screws as an alternative to traditional pedicle screw fixation for degenerative spinal stenosis and anterior spine dislocation of the lumbar spine. Early fixation failure after surgery was defined as fixation failure, such as loosening, pull-out, and breakage of the screw on computed tomography (CT) and radiographs at a follow-up of six months. Results: Early fixation failure occurred in 46 out of 311 cases (14.8%), screw loosening in 46 cases (14.8%), pull-out in 12 cases (3.9%), and breakage in four cases (1.3%). An analysis of the site where the fixation failure occurred revealed the following, L1 in seven cases (15.2%), L2 in three cases (6.5%), L3 in four cases (8.7%), L4 in four cases (8.7%), L5 in four cases (8.7%), and S1 in 24 cases (52.2%). Among the distal cortical bone screws, fixation failures such as loosening, pull-out, and breakage occurred mainly in the S1 screws. Conclusion: Cortical-bone trajectory screw fixation may be an alternative with comparable clinical outcomes or fewer complications compared to conventional pedicle screw fixation. On the other hand, in case with osteoporosis and no anterior support structure particularly at L5-S1 fusion sites were observed to have result of premature fixation failures such as relaxation, pull-out, and breakage.

• Journal of agricultural medicine and community health
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• v.47 no.3
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• pp.181-188
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• 2022

Objectives: The prevalence of diabetes mellitus was approximately 16% in populations of over age 30 years, and deaths from diabetes mellitus became the sixth most prevalent cause of death by disease. To assess the relationship between HbA1c and heavy metal level in blood and urine, targeted residents were evaluated in a vast steel industrial complex. Methods: We selected 414 subjects for analysis after applying the following exclusion criterion: 18 persons with diabetes mellitus. They took part in a questionnaire survey and underwent blood and urinary assessments. HbA1c and lead (Pb) level were measured in blood and, cadmium (Cd), inorganic arsenic (iAs) and mercury (Hg) were evaluated in urine. Two subgroups were divided by HbA1c 6.5%. Each subgroup was divided by 10th, 20th, 30th, 40th, 50th, 60th, 70th, 80th and 90th percentile levels of biological exposure index of the heavy metals for logistic regression. Results: Odd ratios have a tendency to increase as they go from the 90th to the 10th percentile of cadmium. However, lead, arsenic and mercury did not have significant relationships with HbA1c. In correction of age, region, gender and smoking history, a higher distribution in the subgroup with cadmium above 0.8318 ㎍/g creatinine (30th percentile) was demonstrated in the subgroup with HbA1c levels above the 6.5%, with an odds ratio of 5.26 (95% C.I. ; 1.44~19.17). Conclusion: This study found a significant correlation between urinary levels of cadmium and HbA1c in correction of several factors. It is meaningful that this outcome may be used as a basis for a study to establish the acceptable limit of urinary cadmium in Korea.