• Journal of the Korea Concrete Institute
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• v.17 no.2 s.86
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• pp.179-189
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• 2005

Corrosion of steel due to chloride attack is a major concern in reinforced concrete structures which are located in the marine environments. In this case, Fick's 2nd law has been used for the prediction of chloride diffusion related with service life of concrete structures. However, those studies were confined mostly to the single deterioration due to chloride only, although actual environment is rather of combined type. The purpose of the present study is, therefore, to explore the influences of carbonation to chloride attack in concrete structures and to investigate the validity of Fick's law to chloride attack combined carbonation. The test results indicate that the chloride ion profiles from Fick's law using the diffusion coefficient of immersion tests is not reflected the effect of separation of chloride ions in carbonation region but valid in sound region in case of combined action. On the other hand, the chloride ion profiles from Fick's law using the diffusion coefficient of Tang and Nilsson's method coincide with test results under dry-wet condition but not under combined condition. The results of present study may Imply that the new method for the measurement of diffusion coefficient is required to predict the chloride ion profiles in case of combined action at early.

• Journal of Environmental Policy
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• v.9 no.1
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• pp.57-81
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• 2010

Since the Republic of Korea is highly dependent on fossil fuels despite high oil prices, it urgently needs to renew its economic and social system to cut carbon emissions and achieve green growth. Therefore, reforming or eliminating subsidies related to the use of fossil fuels is a timely and oppropriate policy recommendation for Korea. It would be a win-win deal for Korean society as it would not only reduce the use of environmentally harmful fossil fuels but also enhance economic efficiency. In particular, cross-subsidies for industrial, agricultural and night thermal-storage power services make up more than 80 percent of all subsidies provided to the entire electric power industry sector of Korea. Of these cross-subsidies, this paper analyzes the electricity subsidy for industries, which takes up the largest share (about KRW 1.6583 trillion yearly), among the environmentally harmful subsidies in the electric power sector. Thus, the paper focuses on the analysis of ripple effect anticipated when this is reformed. To examine the effects of this subsidy reform, price elasticities were estimated using the ARDL (autoregressive distributed lag) model and quarterly data from 1990 to 2007. The main results of this study show that 1) annual energy demand for electric power in the industrial sector would drop by 12,475,930MWh and 2) $CO_2$ emissions would plummet by 2,644,897 tons per year if the subsidy were reformed. We can deduct from this that the abolition of environmentally harmful subsidies in the electric power sector in the Republic of Korea would considerably contribute to $CO_2$ emissions abatement in the country.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.729-734
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• 2004

This study was performed to analyze the sequence variations of mtDNA D-loop and their effects on milk in Hanwoo(Korean cattle). The resulting sequences were compared with previously published sequences for other cattle breeds (GenBank JOI394). The Polymerase Chain Reaction was performed to amplify a total of 964 bp between nucleotide 15758 and 383 within D-loop region of mtDNA using specific primers. Twenty polymorphic sites by nucleotide substitution were found in mtDNA D-loop region of Hanwoo. The frequencies of positions at 8, 169, 16042, 16051, 16057, 16093, 16119, 16122, 16209, 16255 and 16302 nt with high levels of sequence polymorphism were 0.150, 0.950, 0.085, 0.138, 0.106, 0.085, 0.138, 0.212, 0.085, 0.148 and 0.180, respectively. The substitution effect at 16119(p<0.1) and 16185(p< 0.05) nt was found significant on milk production. Polymorphism of mtDNA sequence in D-Ioop region could be useful for the analysis of cytoplasmic genetic variation and associations with the other economically important traits and maternal lineage analysis in Hanwoo.

• Korean Journal of Microbiology
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• v.41 no.4
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• pp.262-268
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• 2005

Intoxication of murine macrophages (RAW 264.7) with the anthrax lethal toxin (LeTx 100 ng/ml) results in profound alterations in the host cell gene expression. The role of LeTx in mediating these effects is unknown, largely due to the difficulty in identifying and assigning function to individual proteins. In this study, we have used two-dimensional polyacrylamide gel electrophoresis to analyze the protein profile of murine macrophages treated with the LeTx, and have coupled this to protein identification using MALDI-TOF mass spectrometry. Interpretation of the peptide mass fingerprint data has relied primarily on the ProFound database. Among the differentially expressed spots, cleaved mitogen-activated protein kinase kinase (Mek1) and glucose-6-phosphate dehydrogenase were increased in the LeTx treated macrophages. Mek1 acts as a negative element in the signal transduction pathway, and G6PD plays the role for the protection of the cells from the hyper-production of active oxygen. Our results suggest that this proteomic approach is a useful tool to study protein expression in intoxicated macrophages and will contribute to the identification of a putative substrate for LeTx.

• Korean Journal of Comparative Education
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• v.28 no.1
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• pp.1-24
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• 2018

The objective of the article is to find the research trends and the main traits presented in the keywords on abstracts of research articles of "International Journal of Education Development" from 2002 to 2017. To do this, Text Network Analysis(TNA) was applied targeting 966 papers on the journal and the major research outcomes are as follows. First, the frequency analysis on the keywords showed that the keywords like Administration of education program, Schools and instruction, Regional public administration, Educational support service, Elementary education, and Elementary and secondary school were analyzed more than 100 times and also high in centrality degree. Second, the analysis results of the keywords presented in those research articles by development goal periods showed that several new keywords like Elementary education, Elementary and secondary school, Education quality, Secondary education, Educational planning have emerged frequently after SDGs and these keywords showed high in their centrality analysis. Third, the analysis on education level showed that the keywords like Elementary education, Administration of education program, School children were high in frequency and centrality degree in Elementary level. In secondary level, Schools and instruction, Administration of education program, Academic achievement were high, and in high level, college and university was high, respectively.

• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.684-689
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• 2021

In this paper, we develop a cost effective and disposable voltammetric sensing platform involving screen-printed carbon electrode (SPCE) modified with the nanocomposites composed of multi-walled carbon nanotubes, polyelectrolyte, and tyrosinase for bisphenol A. This is known as an endocrine disruptor which is also related to chronic diseases such as obesity, diabetes, cardiovascular and female reproductive diseases, precocious puberty, and infertility. A negatively charged oxidized multi-walled carbon nanotubes (MWCNTs) wrapped with a positively charged polyelectrolyte, e.g., polydiallyldimethylammonium, was first wrapped with a negatively charged tyrosinae layer via electrostatic interaction and assembled onto oxygen plasma treated SPCE. The nanocomposite modified SPCE was then immersed into different concentrations of bisphenol A for a given time where the tyrosinase reacted with OH group in the bisphenol A to produce the product, 4,4'-isopropylidenebis(1,2-benzoquinone). Cyclic and differential pulse voltammetries at the potential of -0.08 V vs. Ag/AgCl was employed and peak current changes responsible to the reduction of 4,4'-isopropylidenebis(1,2-benzoquinone) were measured which linearly increased with respect to the bisphenol A concentration. In addition, the SPCE based sensor showed excellent selectivity toward an interferent agent, bisphenol S, which has a very similar structure. Finally, the sensor was applied to the analysis of bisphenol A present in an environmental sample solution prepared in our laboratory.

• Korean Journal of Heritage: History & Science
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• v.51 no.4
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• pp.192-207
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• 2018

The Hyangwonjeong and Chwihyanggyo located in the back garden of Gyeongbokgung Palace have mainly been investigated by referring to historical records about the reign of King Gojong and various drawings thought to have been made in the late Joseon period. Because the current Chwihyanggyo was rebuilt temporarily after being burned to the ground during the Korean War, its form and the location of its reconstruction are not grounded on any accurate historical investigation. Although there are some photos of the Chwihyanggyo that were taken between the end of the Joseon period and the Japanese colonial era, there is no information about the photographer or when they were taken, and it is hard to see which photos show the original Chwihyanggyo Bridge with them. The Cultural Heritage Administration, which is currently promoting the restoration of the Chwihyanggyo, has recognized this problem and initiated research on the matter. In 2017, an excavation survey successfully identified the original location of the Chwihyanggyo, as well as that of Hyangwonji Gado (假島), and the shape of the first foundation stone in the pier. With these findings it was possible to infer the ways in which the Chwihyanggyo has changed over the years. Moreover, by measuring the AMS (Accelerator Mass Spectrometer) of the samples collected in the mounding layer of the Gado where the Hyangwonjeong is located, it was discovered that the Hyangwonjeong was constructed sometime after the Imjin waeran (Japanese Invasion of Korea in 1592), which means that the theory that 'the late Joseon Hyangwonjeong was not the former early Josenn Chwirojeong' is groundless. Judging by the materials found to date, we can reasonably assume that the Chwihyanggyo and Hyangwonjeong must have been built around the same time that Geoncheonggung Palace was founded in the late Joseon period.

• The Korean Society of Law and Medicine
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• v.23 no.2
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• pp.119-139
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• 2022

Brain stimulation technology that administers electrical and magnetic stimulation to a brain has shown a significant level of possibility for treating a wide range of various neurological and psychiatric disorders. Depending on its nature, the technology is defined either as invasive or non-invasive, and deep brain stimulation (DBS) is one of the most well-known invasive brain stimulation technologies. Currently categorized as grade 4 medical device in accordance with Guideline On Medical Devices And Their Grades, a Notification of Ministry of Food and Drug Safety (MFDS), the DBS has been used as a stable treatment for several diseases. At the same time, the DBS technology has recently achieved substantial advancement, encouraging active discussions for its use from various perspectives. On the contrary, debates over legal regulation related to the use of DBS has relatively been smaller in numbers. In this context, this article aims to 1) introduce the DBS technology and its safety in setting out the tone; 2) touch upon major legal issues that would potentially rise from its use for four different purposes of treatment, clinical study, areas of non-standard treatment where no other methods are available, and enhancement; and finally 3) highlight disputes concerning common emerging issues observed in the aforementioned four purposes from the viewpoint of legal responsibility and liability of using the DBS, which are benefit-risk assessment, physicians' duty of information, patients' capacity to consent, control for device, and insurance coverage.

• Composites Research
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• v.34 no.6
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• pp.357-372
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• 2021

The energy harvesting device is known to be promising as an alternative to solve the resource shortage caused by the depletion of petroleum resources. In order to overcome the limitations (environmental pollution and low mechanical properties) of piezoelectric elements capable of converting mechanical motion into electrical energy, many studies have been conducted on a polymer matrix-based composite piezoelectric energy harvesting device. In this paper, the output performance and related applications of the reported piezoelectric composites are reviewed based on the applied materials and processes. As for the piezoelectric fillers, zinc oxide, which is advantageous in terms of eco-friendliness, biocompatibility, and flexibility, as well as ceramic fillers based on lead zirconate titanate and barium titanate, were reviewed. The polymer matrix was classified into piezoelectric polymers composed of polyvinylidene fluoride and copolymers, and flexible polymers based on epoxy and polydimethylsiloxane, to discuss piezoelectric synergy of composite materials and improvement of piezoelectric output by high external force application, respectively. In addition, the effect of improving the conductivity or the mechanical properties of composite material by the application of a metal or carbon-based secondary filler on the output performance of the piezoelectric harvesting device was explained in terms of the structure of the composite material. Composite material-based piezoelectric harvesting devices, which can be applied to small electronic devices, smart sensors, and medicine with improved performance, can provide potential insights as a power source for wireless electronic devices expected to be encountered in future daily life.

• Clean Technology
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• v.28 no.2
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• pp.193-200
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• 2022

The term environmental, social and governance (ESG) was first used in the 2003 United Nations Environmental Programme Finance Initiative (UNEP FI). Among the three areas of ESG, environment refers to the impact of companies on the environment. Environmental factors address climate change policies and attempts to reduce emissions, waste and natural resource consumption. Social factors refer to the direction in which a company can improve the social impact of stakeholder includes employees, customers, communities, and governments involved in direct or indirect interaction with the organization itself and the company. Governance factors refer to stakeholders who make major decisions, the composition of the board of directors, their diversity and independence, and the internal policies that set limits and expectations for decision-making. Research related to ESG management is part of corporate social responsibility, sustainability, corporate or financial performance, and social responsibility investment. Through case studies and data-based empirical studies, it was confirmed that ESG management companies had positive results for most of the ESG related fields. Through literature analysis of domestic and international ESG history, introduction background, and management performance, this paper presents theoretical, practical implications by confirming that ESG's introduction and operation strategies are strong competitive strategies that directly affect corporate growth by creating attractive factors.