• Geomechanics and Engineering
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• v.33 no.1
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• pp.29-40
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• 2023

Xanthan gum and starch compound biopolymer (XS), an environmentally friendly soil-binding material produced from natural resources, has been suggested as a slope protection material to enhance soil strength and erosion resistance. Insufficient wet strength and the consequent durability concerns remain, despite XS biopolymer-soil treatment showing high strength and erosion resistance in the dried state, even with a small dosage of soil mass. These concerns need to be solved to improve the field applicability and post-stability of this treatment. This study explored the utilization of an alkaline-based cation crosslinking method using calcium hydroxide and sodium hydroxide to induce non-thermal gelation, resulting in the enhancement of the wet strength and durability of biopolymer-treated soil. Laboratory experiments were conducted to assess the unconfined compressive strength and cyclic wetting-drying durability performance of the treated soil using a selected recipe based on a preliminary gel formation test. The results demonstrated that the uniformity of the gel structure and gelling time varied depending on the ratio of crosslinkers to biopolymer; consequently, the strength of the soil was affected. Subsequently, site soil treated with the recipe, which showed the best performance in indoor assessment, was implemented on the field slope at the bridge abutment via compaction and pressurized spraying methods to assess feasibility in field implementation. Moreover, the variation in surface soil hardness was monitored periodically for one year. Both slopes implemented by the two construction methods showed sufficient stability against detachment and scouring, with a higher soil hardness index than the natural slope for a year.

• Journal of the Korea Institute of Building Construction
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• v.23 no.3
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• pp.261-272
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• 2023

This research concentrates on the potential explosion hazards that could arise from unforeseen accidents in the rapidly proliferating hydrogen refueling stations and Energy Storage System(ESS) facilities. It underscores the pivotal role of structural protection technology in alleviating such risks. The research contributes primary data for the formulation of structure protection design by assessing the impact resistance across various reinforcement techniques used in cement composites. The experimental results elucidate that reinforced concrete, serving as the quintessential structural material, exhibits a 20% advancement in impact resistance in comparison to its non-reinforced counterpart. In situations typified by rapid loads, such as those seen with high-velocity impacts, the reinforcement of the matrix with fibers is demonstrably more beneficial than local reinforcement. These insights accentuate the importance of judiciously choosing the reinforcement method to augment impact resistance in structural design.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.251-257
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• 2012

Human body communication means transmitting and receiving data through human body medium or through free space along with the human body skin. Electric field distribution around the human body between the transmitter and the receiver were calculated at five different frequencies with 5 MHz interval between 10 MHz and 30 MHz. Commercial electromagnetic simulation tool was used for the calculation of E-field distributions applying the Korean standard male model including 29 different kinds of human tissues. After calculating specific absorption rate(SAR) values on back of the hand, it was compared with International Commission on Non-Ionizing Radiation Protection(ICNIRP) human protection guideline. While conductivities(${\sigma}$) and relative permittivities(${\varepsilon}_r$) of the human tissues for each frequency were input as the analyzing parameters, electric field intensities near both hands were integrated along the integral line between the nearby electrodes for the calculation of the transmitting and receiving voltages whose ratio was defined as channel loss. The calculated channel losses were about ($75{\pm}1$) dB and showed nearly flat response all through the evaluated frequencies.

• Safety and Health at Work
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• v.9 no.4
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• pp.398-407
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• 2018

Background: Occupational skin diseases (OSDs) are frequent in professions with exposure to skin hazards. Thus, a health educational intervention for apprentices of high-risk professions was conducted. It was the aim of this study to gain insight into possible effects of this intervention. Methods: A one-time skin protection seminar was conducted in 140 apprentices of health-related and non-health-related professions [trained cohort (TC)]. In addition, 134 apprentices of the same occupations were monitored [untrained cohort (UTC)]. The OSD-specific knowledge and the skin condition of the hands were assessed at baseline (T0), after the seminar (T1), and after 6 (T2) and 12 months (T3). Results: The OSD-specific knowledge increased in all cohorts from T0 to T3, but we found a significantly higher knowledge in the TC at T2 (p < 0.001, t = 3.6, df = 196, 95% confidence interval = 0.9, 3.3) and T3 (p < 0.001, t = 3.8, df = 196, 95% confidence interval = 1.0, 3.2) compared to the UTC. Our results indicated a better skin condition of the hands in the TC of the health-related professions but not in the non-health-related professions. Conclusion: The study indicates that an educational intervention may positively influence the disease-specific knowledge and the prevalence of OSD in apprentices. However, definite conclusions cannot be drawn because of the heterogeneous study cohorts and the study design. Future research should aim at tailoring primary prevention to specific target groups, e.g., in view of the duration and frequency of skin protection education, different professions, and gender-specific prevention approaches.

• Knowledge Management Research
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• v.22 no.4
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• pp.157-172
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• 2021

Information security companies were established in earnest from the mid-late 1990s to early 2000s, far shorter than other national key industries. Nevertheless, the information security industry has made rapid progress. It is expected that the proportion of the information security industry will increase rapidly with the development of advanced technology along with the 4th industrial revolution. As COVID-19, which occurred at the end of 2019, spreads around the world in 2020, non-face-to-face services and digital transformation are accelerating, and cyber threats to users are also increasing. However, there are limitations in responding to new Cyber Security threats due to the shortage of information protection manpower, insufficient security capabilities of domestic companies, and the narrow domestic information protection market. This study examines the external environmental factors of information security companies such as government information protection system operation, government influence, government support, partnership between information security companies, and internal environmental factors such as top management support, financial status, human resources, organizational capability, This study was conducted using empirical data to analyze whether it affects innovation capability and whether organizational capability and innovation capability affect financial and non-financial performance. The results of this study can be used as basic data to suggest policies and implications for information security, and to strengthen the competitiveness of the information security industry.

• Clean Technology
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• v.29 no.2
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• pp.118-125
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• 2023

Once a site is contaminated with polychlorinated biphenyls (PCBs), serious environmental and human health risks are inevitable. Therefore, innovative but economical in situ remediation technologies must be immediately applied to the contaminated site. Recently, nanoscale zero-valent iron (nano-ZVI) particles have successfully been applied for the dechlorination of various chlorinated organic compounds like TCE, PCE and DDT, and they are considered to be environmentally safe due to the high abundance of iron in the earth's crust. Nano-ZVIs are much more reactive than granular ones, but tend to agglomerate due to their high surface energy and magnetic properties. In order to prevent them from being agglomerated toward larger particles, TiO₂ was used as a support to immobilize the nano-ZVI particles as much as possible. 10wt% ZVI/TiO₂ was prepared by adding NaBH₄ slowly into an FeSO₄/TiO₂ aqueous slurry. In spite of their non-uniformity in size, the nano-ZVI particles were quite successfully dispersed onto the exterior surface of a non-porous TiO₂ powder. The ZVI/TiO₂ was then employed to degrade Aroclor 1242, a kind of PCBs standard, in spiked soil, and its reactivity towards the degradation of Aroclor 1242 was investigated. The fabricated ZVI/TiO₂ degraded Aroclor 1242 in soil quite effectively, but the creation of remaining dechlorinated compounds, possibly high molecular weight hydrocarbons, in the soil was unavoidable.

• Food Science and Preservation
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• v.22 no.3
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• pp.335-344
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• 2015

The objective of this study was to determine the rheological characteristics and sensory evaluation of yanggaeng by using the functional properties of Momordica charantia. Dried Momordica charantia was roasted at $180^{\circ}C$ to remove its bitter taste. The results of the study were as follows : The phenolic compound of Momordica charantia was $6.30{\pm}0.17mg/g$ in water extracts, which was the highest extractive rate. The anti-oxidant activity of non-roasted and roasted samples was determined in various phenolic concentrations at $50{\sim}200{\mu}g/mL$. The DPPH activities of non-roasted and roasted Momordica charantia water and ethanol extracts were 74.06~92.71% and 86.06~94.07%, respectively. The ABTS were 36.26~98.03% and 67.02~99.60% in water and ethanol extracts, respectively. The anti-oxidant protection factor of water and ethanol extracts were 2.19~2.25 PF and 2.20~2.36 PF respectively, and TBARS were 13.81~40.97% and 23.32~82.47%, respectively. The anti-oxidant activity of ethanol extracts was higher than that of water extracts at low phenolics concentration of $50{\mu}g/mL$, while the roasted sample was higher than the sample that was not roasted. The ${\alpha}$-glucosidase inhibition activity of non-roasted Momordica charantia ethanol extracts was higher than that of water extracts, showing that there were increasing pattern depending on the increases in the phenolics concentration of Momordica charantia. The texture, such as hardness, springiness, cohesiveness, chewiness and color changed in proportion to the concentration of Momordica charantia powder. Moreover sensory characteristics, such as color, flavor, taste, texture and overall acceptability of the non-roasted sample changed in proportion to the concentration of Momordica charantia powder. However, in the roasted sample, the sensory characteristics was improved at a lower concentration (below 1%). Thus, when the yanggang was prepared by Momordica charantia powder as a minor ingredient, it would be desirable to add it after roasting, in consideration of its functional and sensory properties, and at appropriate concentration on below 1%.

• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.260-268
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• 2005

A heat-resisting diatomite protection tube, using diatomite as a main component, was manufactured through an extrusion molding of ceramic slurry in different component ratios. And its mechanical strength, carbon analysis and microstructural non-homogeneity were investigated. After fixing $60wt\%$ of porous diatomite whose particle size was $50\~100\;{\mu}m$, the optimum mixture ratio with composition variables by changing $1\;wt\%$ of each component that was silica sol$(4.3\~7.3\;wt\%)$ as an inorganic binder, CMC (Sodium CarboxyMethyl Cellulose $(6\~9\;wt\%)$) as an organic binder and paper powder$(4.7\~7.7\;wt\%)$ was obtained. As a result of the investigation on a composition containing $60\;wt\%$ diatomite, $5.3\;wt\%$ silica sol, and $7\;wt\%$ CMC, a heat-resisting protection tube that could be used as a molten steel probe for measuring the temperature and components of molten steel was developed. The bending strength, compressive strength, and elastic modulus of the protection tube developed, that contained $\le2.3\;wt\%$ carbon, were 7.1 MPa, 7.5 MPa, and 1090 MPa, respectively.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.715-723
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• 2013

Following the social consensus for the need to stop sexual violence, the government has amended juvenile sex protection laws to impose fees on education practitioners who do not report sexual crimes against women, and amended the 'domestic violence prevention and victim protection laws' (2012. 2) so that the police can investigate on site. However, regardless of these wide efforts, the reality is that sexual crimes against the socially weak do not seem to be dwindling, raising concerns of the effectiveness of such amendments. Generally sexual crimes are hard to prove, and even if reports are filed, most cases are dropped with non-prosecution disposition. Victims are usually limited to women and children and this leads to secondary victims. As this thesis states, developed countries have a more systematic protection methods than our country. Therefore, the purpose of this thesis lies on the construction of public safety infrastructure for the protection of sexual abuse victims (enhancing safety protocols with related organizations, implementing a bill of rights for the victims, prevention-centered police education, amendments to current law) to limit human rights violations and criminal injuries.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.54-59
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• 1999

In order to investigate the behavior of the herbicide metolachlor [2-chloro-6'-ethyl-N-(2-methoxy-1-methylethyl)aceto-O-toluidide] in fish, carps (Cyprinus carpio L.) were exposed to the herbicide at $LC_{10}$(1.93 mg/L) for 4 days. Metolachlor dissolved in water was absorbed rapidly into carps to mark the maximum concentration 6 hours after exposure. The amounts of the $^{14}C$-metolachlor and its metabolites absorbed in gall were much higher than those in the other parts, strongly suggesting that biliary excretion involving enterohepatic recirculation could be an important route for the elimination of metolachlor. The $^{14}C$-radioactivity distributed into aqueous phase fraction in test water and in carp extract was increased in time-dependent manner. Extraction rate of $^{14}C$ absorbed in carp tissues was decreased remarkably up to 6 hours after exposure, suggesting that the possible polar metabolites of metolachlor were transformed into the conjugates to form non-extractable bound residues.