• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.155-161
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• 2000

Recently, environmental pollution has become a big problem in industry and many researches have been done in order to preserve the environment. In the grinding process, the coolant has great influence on environment. It contains several chemicals(sulfur, phosphorus and chlorine) to improve the grinding efficiency. If these additives go into the workplace atmosphere, it is harmful for workers. It can also cause the environment pollution. Because of these reasons many studies have been done to minimize the amount of coolant. However the small amount of coolant can cause the thermal defect on the ground surface layer. This study forced the effects of the compressed cold air when the spindle shaft materials(SCM4 & SCM21) were cylindrical ground with WA wheel. The compressed cold air was used as the coolant and grinding performance was compared with that of the conventional grinding fluids(emulsion). Many experiments were carried out with these two cooling materials. The surface roughness, residual stress, and roundness were measured for the cylindrical grinding. The test results showed that the compressed cold air was very useful as the cooling materials for grinding process. It was also efficient to minimize the thermal defects of workpiece and could also play a role in solving environmental pollution.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.204-210
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• 2016

This paper presents an experimental analysis of the growth and oxidation processes of soot particles generated in an isooctane diffusive laminar flame due to incomplete combustion. The effects of iron-based diagnostics were employed to measure the elastic scattering light from soot particles in a flame at different flame heights, and the differential scattering coefficients were calculated through a calibration process. The growth and oxidation of soot particles in flame was investigated by comparing differential scattering coefficients, and the soot volume fraction was seen to decrease in the soot oxidation process. In the same manner, the differential scattering coefficients were calculated for iron-based fuel-additive seeded flame, and these coefficients were revealed to be smaller than those obtained in the fuel-additive unseeded flame. In addition, transmission through the radial direction of the flame was measured, and transmission in the soot oxidation regime was approximately 5% higher for the seeded flame. The propensity of the data coincided well with the differential scattering coefficients, and it can be concluded that the iron component of the fuel additive plays a crucial role as a catalyst, which eventually enhanced soot particle oxidation.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.512-521
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• 2015

In this research, environmental friendly organic acid containing microetching system to improve adhesion strength between photoresist resin and Copper Clad Laminate(CCL) was developed without using strong oxidant $H_2O_2$. Etching rate and surface contamination on CCL were examined with various etching conditions with different etchants, organic acids and additives. to develope an optimum microetching condition. Etching solution with 0.04 M acetic acid showed the highest etching rate $0.4{\mu}m/min$. Etching solution with the higher concentration of APS showed the higher etching rate but surface contamination on CCL is very serious. In addition, stabilizer solution also played an important role to control the surface contamination. As a result of research, the etching solution containing 0.04 M of acetic acid, 0.1 M of APS with 4 g/L of stabilizer solution(ST-1) was best to improve adhesion between CCL and photoresist resin as well as showed the most clean and rough surface with the etching rate of $0.37{\mu}m/min$.

• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.299-304
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• 2020

Nanoparticles play an important role as a catalyst in many chemical syntheses. Colloidal nanoparticles were usually synthesized with reducing, capping, and shape directing agents which induce surface poisoning of catalysts. A new green synthesis for silver nanoparticles was developed by utilizing less additives which could be a hazardous waste. A crystallization technique was employed to reduce the amount of reducing and capping agents during synthesis resulting in less surface poisoning of the nanoparticle. The synthesized Ag nanoparticles using monosaccharides and disaccharides as reducing agents could be used as a catalyst for the redox reaction of resazurin and the mechanism of the reaction using Ag nanoparticles was studied.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.2 s.35
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• pp.129-134
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• 2005

Electroplating copper is the important role in formation of 3D stacking interconnection in SiP (System in Package). The I-V characteristics curves are investigated at different electrolyte conditions. Inhibitor and accelerator are used simultaneously to investigate the effects of additives. Three different sizes of via are tested. All via were prepared with RIE (reactive ion etching) method. Via's diameter are 50, 75, $100{\mu}m$ and the height is $100{\mu}m$. Inside via, Ta was deposited for diffusion barrier and Cu was deposited fer seed layer using magnetron sputtering method. DC, pulse and pulse revere current are used in this study. With DC, via cannot be filled without defects. Pulse plating can improve the filling patterns however it cannot completely filled copper without defects. Via was filled completely without defects using pulse-reverse electroplating method.

• Korean Journal of Organic Agriculture
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• v.20 no.2
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• pp.185-200
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• 2012

It has been reported that world population continues to increase so that a matter of food security can be a world-wide problem for mankind. An anticipated rise in world population of 30% and the subsequent increased demand for food brings with it challenges in terms of global resource usage and food security. However, ruminant livestock production and consumption make a large contribution to the greenhouse gas (GHG) emissions which can be attributable to food production. Given the association between GHG and climate change, this is clearly of great concern to the livestock industry worldwide. Nevertheless, ruminant livestock also play an important role in global food security as they can convert the plant cell wall materials and non-protein nitrogen compounds, found widely in plants but indigestible to all monogastric animals including man, into high value proteins for human consumption. Much effort has been made to maximize animal production, feed conversion ratio, and to improve animal breeding in ruminant agriculture. In addition improving feed formulation techniques, developing chemical additives, plant extracts, and new plant varieties for grazing have been tested. Future ruminant production systems will need to capitalize on important benefits of ruminants. It is therefore suggested that ruminant agriculture has a key role to play in maintaining and enhancing provision of quality proteins and essential nutrients for human being but the challenge of reducing GHG emissions, and methane in particular, needs to be successfully addressed.

• Korean Journal of Poultry Science
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• v.42 no.3
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• pp.247-256
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• 2015

There are approximately 1,500 broiler farms in Korea, each raising 55,000 birds. Ninety-five percent of the farms are contracted with Integration Company. According to the Korean broiler performance index, broilers in Korea are marketed at 32 days with 1.52 kg of body weight. In contrast, the market age and body weight of broilers are 47 days/2.8 kg in the United States and 42 days/2.5 kg in Europe. Because of the younger market age of the Korean broiler, the pre-starter feed is important. Chicks exhibit poor absorption of dietary nutrients up to 7 days after hatching due to an immature digestive system and low enzyme secretion rate and activity. At the beginning of hatching, chicks obtain their nutrients from the egg yolk sac. It is highly recommended that chicks, after consuming the nutrients in the egg yolk sac, are given supplemented pre-starter feed to increase early growth rates and improve the performance of broiler production. Pre-starter nutrient requirements are not expressed in NRC, so Korean feeding standards for poultry and commercial breeding companies determine the nutrient requirements of pre-starter broiler chickens. Three approaches are followed to formulate specially designed pre-starter feeds for broiler chicks: (i) selective use of raw materials, (ii) proper standards of nutrient supply, and (iii) application of feed additives such as exogenous enzymes. In the selection of raw materials, those with high digestibility can be used. The absorption rate of carbohydrates in grains can be increased through feed processing at high temperature and high pressure. Soy proteins and fish meal can also be added as protein sources. As an energy source, vegetable oils are preferred over animal fats because of the former's high digestibility. It is suggested that the levels of proteins and amino acids are higher in pre-starter feed than in starter feed. With regard to energy, the sources of energy are more important than the levels of energy in feed. Feed additives such as exogenous enzymes can be used to improve nutrient digestibility. In addition, organic acids and plant extracts can be used as alternatives to animal growth promoters to stimulate immunity and prevent diseases. The growth performance of broilers is affected by various factors, such as management and disease control, in addition to the nutritional strategy; however, nutritional strategies play an important role in improving the productivity of broilers. Therefore, nutritional strategies, along with management and disease control, are required for improving the productivity of broilers in Korea.

• Korean Journal of Heritage: History & Science
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• v.57 no.2
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• pp.6-25
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• 2024

This study concentrated on a report on the results of smelting experiments conducted eight times by the Jungwon National Research Institute of Cultural Heritage, put together the goals and results of the operation, and examined changes in the content of experiments and in the experimental results. First, changes related to operation, such as the ratio of raw materials to fuel and the presence or absence of additives, were reviewed depending on the operation goal. In addition, the results of metallurgical analysis of raw materials, formations, and byproducts were summarized and reviewed by comparing them with materials excavated from the ruins. The operation method varied up to the eighth smelting experiment in terms of iron ore roasting, additives, and raw material/fuel ratio. After reviewing the results again, pure iron with a low carbon content began to be confirmed through metallurgical analysis. As a result, it was confirmed that the charging ratio of raw materials and fuel plays an important role depending on the purpose of production. In addition, most of the products are gray cast iron, and it was deemed that this is due to changes in the internal structure of the pig iron while it was left in the furnace for a long time. The iron was an ingot that was in a molten state even though the carbon content did not reach 4.3%, where the process reaction takes place, and it was deemed to have been caused by excessive operating temperature. Based on the previously reviewed results and the structure and shape of the experimental furnace used in other ironmaking technology restoration experiments, this study finally attempted to restore the structure of an ancient iron smelting furnace, including the furnace's upper structure. By comprehensively referring to the remaining conditions of the excavated iron smelting furnace and the characteristics of the blow pipe, the form of the ancient iron smelting furnace was subdivided into six categories: furnace wall thickness, furnace height, blower height, blow pipe size, furnace inner wall shape, and top shape, and a restoration plan was proposed. To improve the problems of the restoration plan and the Jungwon National Research Institute of Cultural Heritage's experiments that have been conducted through continuous trial and error, an experiment that reflects changes in operating methods by lowering the furnace height and controlling the blowing volume is necessary.

• Fisheries and Aquatic Sciences
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• v.19 no.10
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• pp.40.1-40.14
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• 2016

Background: Due to the paucity of oceanic resources utilized in the preparation of diets for cultured fish, commercial feed producers have been trying to replace fishmeal (FM) using alternative protein sources such as vegetable protein meals (VMs). One of the main drawbacks of using VMs in fish feed is related to the presence of a variety of anti-nutritional factors, which could trigger an inflammation process in the distal intestine. This reduces the capacity of the enterocytes to absorb nutrients leading to reduced fish growth performances. Methods: We evaluated the mitigating effects of butyrate and taurine used as feed additives on the morphological abnormalities caused by a soybean meal (SBM)-based diet in the distal intestine of sea bass (Dicentrarchus labrax). We used three experimental diets, containing the same low percentage of FM and high percentage of SBM; two diets were supplemented with either 0.2% sodium butyrate or taurine. Histological changes in the intestine of fish were determined by light and transmission electron microscopy. Infiltration of $CD45^+$ leucocytes in the lamina propria and in the submucosa was assessed by immunohistochemistry. We also quantified by One-Step Taqman$^{(R)}$ real-time RT-PCR the messenger RNA (mRNA) abundance of a panel of genes involved in the intestinal mucosa inflammatory response such as $TNF{\alpha}$ (tumor necrosis factor alpha) and interleukins: IL-8, IL-$1{\beta}$, IL-10, and IL-6. Results: Fish that received for 2 months the diet with 30% soy protein (16.7% SBM and 12.8% full-fat soy) developed an inflammation in the distal intestine, as confirmed by histological and immunohistochemistry data. The expression of target genes in the intestine was deeply influenced by the type of fish diet. Fish fed with taurine-supplemented diet displayed the lowest number of mRNA copies of IL-$1{\beta}$, IL-8, and IL-10 genes in comparison to fish fed with control or butyrate-supplemented diets. Dietary butyrate caused an upregulation of the $TNF{\alpha}$ gene transcription. Among the quantified interleukins, IL-6 was the only one to be not influenced by the diet. Conclusions: Histological and gene expression data suggest that butyrate and taurine could have a role in normalizing the intestinal abnormalities caused by the SBM, but the underling mechanisms of action seem different.

• Toxicological Research
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• v.22 no.4
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• pp.381-390
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• 2006

Astaxanthine is a pigment that belongs to the family of the xanthophylls, the oxygenated derivatives of carotenoids whose synthesis in plants derives from lycopene. Astaxanthine is also a carotenoid widely used in salmonid and crustacean aquaculture to provide the pink color characteristic of that. Recent study reported that astaxanthine has the role as a detoxicant against the free radicals. On our study, we estimated the genotoxicity in ICR mice and possibility as antioxidant reagents of mutant Phaffia rhodozyma strain over expressing the astaxanthine by gamma-lay and carophyll pink including astaxanthine in apoE knock out mice, respectively. In our study, we administered Phaffia rhodozyma (2 mg and 3 mg) and carophyll pink for 4 and 8 week. The clinical sign and mortality were not detected compared with control groups. In the mutant frequency of hprt gene and chromosome aberration in splenic cells, there was not detected abnormality. There was not critical change in hematological and serum biochemical test compared to control. In expression level of repair enzyme, increase of catalase were detected and increase of expression level of Nrf-2 was detected in Phaffia rhodozyma (3 mg) and carophyll pink in 8 week treated group. In GSH level, the group of treated with Phaffia rhodozyma (3 mg) showed the increase of the GSH. In conclusion, mutant Phaffia rhodozyma and caphyll pink may be applied to the effective food additives to reduce the free radical.