• Toxicological Research
• /
• v.35 no.3
• /
• pp.249-255
• /
• 2019

Cadmium is a strong toxic heavy metal which presents in paints and liquid wastes and causes oxidative stress in fish. On the other hand, lead is widely used for different purposes, e.g. lead pipes, it targets vital organs such as liver and kidney causing biochemical alterations. The present study evaluates the effects of 60 days exposure to Cd and Pb either single or combined together in African catfish. Sixty-four fishes were divided into 3 groups and exposed to $CdCl_2$ (7.02 mg/L) or $PbCl_2$ (69.3 mg/L) or a combination of them along with control group. Activities of acid phosphatase (ACP), lactate dehydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G-6-PDH) were estimated. Moreover, gill, liver and kidney were assayed for activities of superoxide dismutase (SOD), catalase (CAT) and levels of glutathione (GSH) and malondialdehyde (MDA). Individual exposure showed that both Cd and Pb significantly decreased LDH activity and SOD activity in the kidney. Pb significantly increased G-6-PDH activity and decreased GSH level in the gill. CAT activity in liver and kidney elevated significantly on Cd exposure while lead caused a significant depletion in the liver and significant elevation in the kidney. Both Cd and Pb significantly increased MDA levels in liver and kidney while Pb increased its level in gills. The combined exposure resulted in normalization of LDH, G-6-PDH activity, and CAT activity in liver and kidney as well as GSH level in both tissues and MDA in gill and kidney. The combination increased SOD activity and MDA level in liver and decreased SOD activity in kidney and GSH level in gills. In conclusion, the antioxidant system of African catfish was adversely affected by prolonged exposure to Cd and Pb. The combined exposure caused less damage than individual exposure and returned most parameters to those of controls.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.31 no.3
• /
• pp.137-142
• /
• 2021

In this study, the development of the room temperature curable silica-based coating compositions for anticorrosive and antifouling performance in marine environments was carried out. The marine (plant) structures with many exposed parts are operated in harsh marine environments such as strong ultraviolet rays, extreme temperature differences and salt water corrosion. Organic paints that are easily degraded under these environments and easily eroded by physical stimuli such as waves can not play a role properly. Dense ceramic coatings on marine structures provide careful protections even in saltwater environments due to their high hardness and rust resistance. Therefore, in the case of ceramic coatings, their use and application range in marine structures can be greatly improved due to their functional advantages. In the present study, silica-based coating compositions based on colloidal silica with silane coupling agents, curing salts, and ceramic fillers were developed, and their applications as protective coatings for corrosion protection and fouling prevention in seawater were also studied.

• Journal of Environmental Science International
• /
• v.30 no.12
• /
• pp.1041-1051
• /
• 2021

The purpose of this study was to identify for extenders, adhesives, colorants, and fungicides suitable for the production of high-quality film-coated seeds of Chinese cabbage. In addition, the effect of various additives used for film coating on the germination of coated seeds and seedling vigor was investigated to establish appropriate treatment conditions for film coating efficiency. The germination rate and germination speed in Chinese cabbage film-coated seeds did not differ significantly depending on the type and concentration of the extender, while the use of Talc resulted in superior granulation capacity and adhesion of the seed coat in comparison to Zeolite. There was no significant difference in the germination rate depending on the type of adhesive used for film coating of Chinese cabbage seeds, but the germination rate was slightly slower in the film-coated seeds using carboxymethyl cellulose as an adhesive. On the other hand, the seeds coated with a film using 1% PVA as an adhesive not only maintained hardness enough to withstand external pressure, but also showed a high germination rate. In addition, the suitable disinfectant for film coating was venoram, and the treatment concentration was good at 250 mg·L^-1. The type of colorant used in the film-coated seeds of Chinese cabbage did not significantly affect the germination rate, germination speed, and seedling vigor. The seeds film-coated using the liquid colorant were superior in appearance to the seeds film-coated with the solid colorant, which implies the possibility of reduction in the manufacturing costs by using the water-soluble paints as colorants for film-coated seeds.

• Journal of the Korean Geosynthetics Society
• /
• v.20 no.4
• /
• pp.33-41
• /
• 2021

Feldspar, along with Quartz, are the most frequently produced minerals in Korea; however, the potential value is estimated to be significantly low because of the scarce research on the development and application of material properties, except for their limited use in manufacturing minerals, glass, and paints. In this study, we analyzed the eco-friendly material and reactivity improvement characteristics of weathered feldspar through activation technique. The joint structural features observed on the surface of the weathered feldspar show that the joint arrangements are irregularly distributed, and the cavities are interconnected. Due to the irregularly connected cavities on the surface of weathered feldspar, the reaction area of the weathered feldspar is increased; hence the weathered feldspar is considered as a highly reactive pozzolan material when combined with cement. As a result of applying the thermal, mechanical, and chemical activation techniques to improve the functionality of the weathered feldspar, the cation exchange capacity, density, and uniaxial compression strength characteristics were improved. It is considered that weathered feldspar by these porous characteristics can be used as an eco-friendly construction material with excellent physical and chemical properties.

• Journal of the Korean Applied Science and Technology
• /
• v.38 no.6
• /
• pp.1533-1542
• /
• 2021

Eco-friendly polyurethane can be defined as a highly utilized material used in various fields. The various structural properties of the synthesis of isocyanates and polyols provide versatility and customization for use in the manufacturing field. The characteristics of polyurethane vary widely from soft touch coatings to hard building materials like rocks. These mechanical, chemical and biological properties and ease of alignment are drawing tremendous attention not only in the field of research but also in related industries. In order to improve the performance of water-dispersible polyurethane materials, it can be derived through processes such as adjusting the blending of raw materials and adding additives and nanomaterials. This study highlights the basic chemical structure of eco-friendly water-dispersible polyurethane in the fields of medical science, automobiles, coatings, adhesives, paints, textiles, marine industries, wood composite materials, and clothing.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.05a
• /
• pp.217-218
• /
• 2021

With the prolonged Covid-19 epidemic, movement restrictions such as social distancing are prolonged, and as people stay indoors for a longer time, interest in indoor air pollution is increasing. Indoor air quality is not easily purified unlike outdoors. Among indoor building materials, paints and flooring contain formaldehyde that causes sick house syndrome and VOCs that contain carcinogenicity and harmfulness. For modern people who spend a lot of time living indoors for more than an hour, the occurrence of these harmful substances can be said to be fatal. In response to these risks, in July 2019, the government reinforced the standards for indoor air quality to protect the public's health by raising the detection standards for fine dust, ultrafine dust, and formaldehyde in indoor multi-use facilities. People use machines such as air purifiers to improve indoor air quality, or make efforts such as periodic ventilation. In order to reduce or support these other ancillary efforts more effectively, to reduce the generation of pollutants in the building itself, or to adsorb or purify pollutants in the air, use carbon black as an admixture to make a cement hardened body, and to grasp basic physical properties and adsorption capacity. And the result is as follows. As a result of the experiment to determine the appropriate amount of carbon black, it was confirmed that the more the amount of carbon black was added, the better it was in the formaldehyde emission test, but the tendency was not clear when measuring the flexural strength, so a further experiment to improve this is needed.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.05a
• /
• pp.25-26
• /
• 2021

Due to COVID-19, the spread of non-face-to-face culture is increasing the time spent indoors. Accordingly, it is necessary to reduce indoor air pollutants. Also, among building materials, there are paints. As the number of coatings increases, the coating film becomes thick, and there is a risk of cracking and falling off. Therefore, this study is to examine the adsorption properties of indoor air pollutants according to the number of coatings of a paint mixed with powdered activated carbon. In the experimental plan, the addition ratio of powdered activated carbon was selected as 30%, and the number of coatings was selected as primcoating, second coat, and finishing coat, and the concentration of formaldehyde and volatile organic compounds were measured. As a result, as the number of coatings increased, the concentration of formaldehyde and volatile organic compounds tended to decrease. This is considered to be due to the fact that not only the physical adsorption acted by the internal pores of the powdered activated carbon, but also because a lot of powdered activated carbon was present on the painted surface as the coating film was formed. However, since it is judged that there is an error in the concentration due to the inflow of external air as the chamber cover is opened to put the test object in the adsorption test process, it is considered that the experimental method needs to be supplemented.

• 중국학논총
• /
• no.58
• /
• pp.91-119
• /
• 2018

As for the various pathological phenomena of the society which is getting worse without any improvement, the film paints the phenomenon nakedly with the cold and cynical gaze on the basis of realism. These attempts originated in the Chinese art world, and they cynically sketched a Chinese society that lost hope after 6·4. The cynicism of the art world contains meanings such as instruction, meanness, passion, indifference, and mockery. In particular, the distrust of the social system after 6·4 and the collapse of the Soviet and Eastern European socialist nations gave the Chinese people a skeptical view of socialism. This situation of the times has a cynical viewpoint to face as it is instead of prudent criticism. This cynical view was embraced by filmmakers who were not silent on The pathological phenomenon of society, and they were directed to films. is a film about the love, separation, suicide, frustration and reconciliation of youth in the era of identity confusion after 6·4. The characters in the film did not mention a single word about the state power that made them do it. based on the characteristics of women in northeast China and the murder that occurred around a woman with a beauty that was not like a laundry employee. Centered around the unresolved slice murder case, expressed human moral ambiguity that does not distinguish good fortune from human instinct for struggle for survival, and portrayed the scenery of a very cold northeast small city. But it does not show any criticism of the crime. Based on the true story of the 2000s, the portrays the uncomfortable aspects of China that established Chinese socialism. A film composed of four short episodes conveys the destiny set by God.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.11 no.3
• /
• pp.234-243
• /
• 2023

The electromagnetic pulse(EMP) is a general term for high-output electromagnetic waves, and is classified into EMP generated from nuclear weapons, non-nuclear EMP, and EMP generated by natural phenomena. Electromagnetic pulses are means that can cause fatal damage to all electronic devices with electromagnetic elements, such as communication devices, mobile phones, computers, TVs, and means of transportation. In this study, the electromagnetic pulse(EMP) shielding effectiveness evaluation of paints according to the type and amount of carbon material was conducted to develop EMP shielding inorganic paint using carbon materials. In order to analyze the improvement of compatibility and dispersibility between materials, experiments were conducted two times with about 27 types of mixture proportions, and the electromagnetic pulse shielding effectiveness was evaluated by the electrical resistance measurement method. As a result of applying the EMP shielding paint developed through this study to shielding concrete, it was confirmed that the shielding performance was improved from about 25 dB to a maximum of 40 dB.

• Land and Housing Review
• /
• v.14 no.4
• /
• pp.103-110
• /
• 2023

People who spend most of their day indoors are continuously exposed to internally and externally generated indoor pollutants. According to a 2022 report from the World Health Organization (WHO), air pollution is the cause of more than 7 million deaths annually worldwide, emphasizing the seriousness of indoor air pollutants. Air pollutants include nitrogen oxides (NOx), formaldehyde (HCHO), and volatile organic compounds (VOCs), which have serious effects on the human body. Photocatalyst is a material that can remove these indoor air pollutants. Photocatalysts not only have the ability to remove dust precursors, but also have antibacterial, sterilizing, and deodorizing functions, making them effective in improving indoor air quality. This study suggests areas and methods in which photocatalysts can be applied to buildings. Fields of application include interior and exterior construction materials such as concrete, as well as organic paints and ventilation devices. If appropriate utilization plans are developed, it may be possible to improve the built environment through reduced indoor and outdoor pollutant levels.