• Journal of Korean Society on Water Environment
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• v.38 no.2
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• pp.82-94
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• 2022

In this study, chemically modified biochar (NSBP500, KSBP500, OSBP500) derived from starfish was utilized to improve the adsorption ability of the SBP500 (Starfish Biochar Pyrolyzed at 500℃) in a solution contaminated with heavy metals. According to the biochar modification performance evaluation batch tests, the removal rate and adsorption amount of NSBP500 increased 1.4 times for Cu, 1.5 times for Cd, and 1.2 times for Zn as compared to the control sample SBP500. In addition, the removal rate and adsorption amount of KSBP500 increased 2 times for Cu, 1.8 times for Cd, and 1.2 times for Zn. The removal rate and adsorption amount of OSBP500 increased 5.8 times for Cu. The FT-IR analysis confirmed the changes in the generation and movement of new functional groups after adsorption. SEM analysis confirmed Cu in KSBP500 was in the form of Cu(OH)₂ and resembled the structure of nanowires. The Cd in KSBP500 was densely covered in cubic form of Cd(OH)₂. Lead(Pb) was in the form of Pb₃(OH)₂(CO₃)₂ in a hexagonal atomic layer structure in NSBP500. In addition, it was observed that Zn was randomly covered with Zn₅(CO₃)₂(OH)₆ pieces which resembled plates in KSBP500. Therefore, this study confirmed that biochar removal efficiency was improved through a chemical modification treatment. Accordingly, adsorption and precipitation were found to be the complex mechanisms behind the improved removal efficiency in the biochar. This was accomplished by electrostatic interactions between the biochar and heavy metals and ion exchange with Ca²⁺.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.545-551
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• 2013

In this study, shot peening technique was employed with shot peening time for durability improvement and surface modification of copper alloy to investigate the electrochemical characteristics and microstructural variations. As a result of shot peening, roughness was distributed over the surface, and homogenization phenomenon was observed with increasing shot peening time due to the enhancement of coverage. The results revealed that hardness increased for shot peened specimens and particularly 3.5 mins of shot-peening time represented a hardness improvement of 52 %, showing similar electrochemical characteristics to that of the un-peened surface.

• Journal of Chest Surgery
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• v.37 no.3
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• pp.235-244
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• 2004

Anatomic correction of the transposition of the great arteries (TGA) or Taussig-Bing anomaly by means of the arterial switch operation is now accepted as the therapeutic method of choice. This retrospective study was conducted to evaluate the risk factors for operative deaths and the efficacy of technical modification of the coronary transfer. 85 arterial switch operations for TGA or Taussig-Bing anomaly which were performed by one surgeon from 1994 to July 2002 at Dong-A university hospital were included in this retrospective study Multivariate analysis of perioperative variables for operative mortality including technical modification of the coronary transfer was peformed. Overall postoperative hospital mortality was 20.0% (17/85). The mortality before 1998 was 31.0% (13/42), but reduced to 9.3% (4/43) from 1998. The mortality in the patients with arch anomaly was 61.5% (8/13), but 12.5% (9/72) in those without arch anomaly. In patients who underwent an open coronary reimplantation technique, the operative mortality was 28.1% (18/64), but 4.8% (1/21) in patients undergoing a technique of reimplantation coronary buttons after neoarotic reconstruction. Risk factors for operative death from multivariated analysis were cardiopulmonary bypass time ($\geq$ 250 minutes), aortic cross-clamping time ($\geq$ 150 minutes), aortic arch anomaly, preoperative event, and open coronary reimplantation technique. Operative mortality has been reduced with time. Aortic arch anomaly and preoperative events were important risk factors for postoperative mortality. However atypical coronary artery patterns did not work as risk factors. We think that the technical modification of coronary artery transfer played an important role in reducing the postoperative mortality of arterial switch operation.

• Clean Technology
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• v.29 no.2
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• pp.102-108
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• 2023

This study applied a hydrothermal carbonization (HTC) method to carbonize sewage sludge in order to satisfy the criteria of the Waste Management Act for recycled products and to explore the possibility of recycling sludge into modification blocks. Cement was mixed with carbonized sludge generated at the optimal temperature and reaction time during HTC. After that, the compressive strengths of the modification blocks were measured by conducting both a performance and leaching test. The results of the leaching test showed that heavy metals were not detected, and the specific gravity and absorption rates were less than 1.7 and 10%, respectively, indicating that all species satisfied the criteria. The results of the compressive strength test showed that a mixing ratio of 5% and 7% with cement cured for 28 days satisfied the criteria of A, B, and C type blocks but a mixing ratio of 3% with cement did not satisfy the criteria of A type blocks after 28 days. However, after additional curing for 42 days, the mixing ratio of 3% also satisfied the A type block criteria. Therefore, the optimal mixing ratio of carbonized sludge and cement was considered to be between 3% and 5% and confirmed that the modified blocks could be utilized as aggregates.

• Science of Emotion and Sensibility
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• v.26 no.1
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• pp.79-86
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• 2023

This study aims to create a highly conductive E-textile made by recycling PET with a Dip-coating process. PET fiber with hydrophobic properties is characterized by the difficulty in imparting great conductivity when both Virgin and Recycled are made of electronic fibers through a Dip-coating process. To advance the effectiveness of the Dip-coating process, a sample made of recycled PET was surface modified for 50 w 5 minutes and 10 minutes employing a Covance-2mprfq model from FEMTO SCIENCE. After that, the sample was immersed in an SWCNT dispersion (.1 wt%, Carbon Co., Ltd.) for 5 minutes, and then dip coating was conducted to allow the solution to permeate well into the sample through a padder (DAELIM lab). After the procedure was completed, the resistance measurement was measured with a multimeter at both ends and then accurately remeasured with a wider electrode. As a result of this contemplation, it was affirmed that great conductivity might be given through an impregnation process through the plasma surface modification. When the surface modification was performed for 10 minutes, the resistance was reduced by up to 2.880 times. Dependent on the results of this research, E-fibers employed in the smart wearable sector can also be made of recycled materials, improving smart wearable products that can save oil resources and reduce carbon emissions.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.223-229
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• 2015

Surface modification is a technology to form a new surface layer and overcome the intrinsic properties of the base material by applying thermal energy or stress onto the surface of the material. The purpose of this technique is to achieve anti-corrosion, beautiful appearance, wear resistance, insulation and conductance for base materials. Surface modification techniques may include plating, chemical conversion treatment, painting, lining and surface hardening. Among which, a surface modification process using electrolytes has been investigated for a long time in connection with research on its industrial application. The technology is highly favoured by various fields because it provides not only high productivity and cost reduction opportunities, but also application availability for components with complex geometry. In this study, an electrochemical experiment was performed on the surface of 5083-O Al alloy to determine an optimal electrolyte temperature, which produces surface with excellent corrosion resistance under marine environment than the initial surface. The experiment result, the modified surface presented a significantly lower corrosion current density with increasing electrolyte temperature, except for $5^{\circ}C$ of electrolyte temperature at which premature pores was created.

• Korean Journal of Community Nutrition
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• v.10 no.4
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• pp.525-535
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• 2005

This study was conducted to investigate the effect of a 3 week low calorie diet (LCD) and a 9 week of behavior modification (BM) program on the weight loss, mineral and vitamin status in 22 obese women. The subject were healthy, obese (PIBW> $120\%$) women aged 20 - 50 Yr and not taking any medications known to influence body composition, mineral or vitamin metabolism During the LCD program, subjects were provided commercial liquid formulas with 125 kcal per pack and were instructed to have a formula for replacement of one meal and at least one regular meal per day within the range of daily 800 - 1200 kcal intake. During the BM program the subjects weekly attended the group nutrition counseling session to encourage themselves to modify their eating behavior and spontaneously restrict their energy intakes. The BM program focused on stimulus control, control of portion sizes and modification of binge eating and other adverse habits. The initial mean energy intake of subjects was 2016.9 $\pm$ 129.8 kcal ($100.8\%$ of RDA) and dropped to 1276.5 $\pm$ 435.7 kcal at the end of a 3 week of LCD program and elevated to 1762 $\pm$ 329.3 kcal at the end of a 9 week of BM program. Carbohydrate, protein and fat intakes were significantly decreased at the end of the LCD but carbohydrate was the only macro nutrient that showed significant decrease (p < 0.05) at the end of the BM program compared to baseline. Calcium and iron intakes decreased significantly (p < 0.01, respectively) with no significant changes in other micronutrients at the end of the LCD. The mean weight of the subjects decreased from 73.8 $\pm$ 8.0 kg to 69.2 $\pm$ 7.7 kg with LCD and ended up with 67.7 $\pm$ 7.1 kg after 9 weeks of BM. The 3 weeks of LCD reduced most of the anthropometric indices such as BMI, PIBW, fat weight, wast-to-hip ratio and subscapular and suprailiac skinfold thickness. The 9 weeks of behavior modification showed slight change or maintenance of each anthropometric measurements. Weight loss and decreased WHR with the diet program induced significantly decreased systolic blood pressure. SGOT, SGPT and serum insulin levels with improved serum lipid profiles. Biochemical parameters related to iron status such as hemoglobin, hematocrit were significantly decreased (p < 0.01) at the end of the LCD. But their mean values were within normal range. The mean serum 25 (OH) vitamin $D_3$ level significantly increased after whole diet program. Serum folate level significantly decreased after 12 weeks of diet program. In conclusion 3 weeks of LCD brought 4.6 kg reduction in body weight without risk of iron, zinc or vitamin D deficiency and 9 weeks of the BM was effective to maintain nutritional status with slightly more weight reduction (1.5 kg). However calcium intake and serum folate should be monitored during the LCD and BM because of increased risk of deficiencies.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.4
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• pp.115-125
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• 2017

In current, as the release of national base map with an equivalent scale and accuracy for the whole territory areas in South Korea, rapid spatial information industry such as national land development, GIS, and car navigation are used in a variety of spatial information industry as decision making method, and a lot of research and policies are proposed for the wide expansion of spatial information industry. For this, as of 2013, it contributes to the latest trend of spatial information field in order to solve the problems for the latest trend of spatial information, replacing modification of base maps as dividing the whole territory to zone with policy transformation by ordinary modifications. Therefore, this paper evaluates the possibility of modification and renewal of national base maps(scale: 1:5,000) using drones which currently get the limelight from a variety of research fields and industries. In particular, as a result of overlapping orthophoto, 3D point clouds extracted from images acquired by low-cost drones, and digital maps which are applied for the tasks of modification and renewal, it presents 0.2m precision and 0.1m accuracy. This means that drone-based photorgammetry technique can be fully utilized in the tasks of digital map modification and renewal because it conforms the error range of work regulation in making the national base maps(scale 1: 5000).

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.5 s.142
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• pp.617-625
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• 2005

The purpose of this study was to develop functional and environment-friendly polyester fabric by irradiating Ultra-Violet, which was produced by the low-pressure mercury lamp. UV irradiation was conducted with various treatment times and distances. Also, pretreatments of solvents and photoinitiator were used to improve the surface modification effects. The effects of UV irradiation on the moisture regain were found to increase gradually with increase of UV treatment time and decrease of treatment distance. Compared the effects of UVC and UVA, UVC was more effective than UVA. Moisture regain and wicking of PET was increased after UV treatment in our experimental condition. And owing to increasing of moisture regain, static charge was decreased. Pretreatment of solvents such as methanol, ethyl ether and addition of photoinitiator such as Benzophenone accelerated surface modification. The moisture regain was increased but wicking was decreased with pretreatment and addition of photoinitiatior. Therefore it is considered as inappropriate f3r clothing because of wicking effects. Yellowness, tensile strength and elasticity slightly decreased after UV irradiation.

• Laser Solutions
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• v.17 no.2
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• pp.19-25
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• 2014

Optical embedded diffraction gratings with the bulk modification in BK-7 glass plates excited by tightly focused high-intensity femtosecond (130fs) Ti: sapphire laser (peak wavelength = 790nm) were demonstrated. The structural modifications with diameters ranging from 400nm to $4{\mu}m$ were photo-induced after plasma formation occurred upon irradiation with peak intensities of more than $1{\times}1013W/cm^2$. The graded refractive index profile was fabricated to be a symmetric around from the center of the point at which low-density plasma occurred. The maximum refractive index change was estimated to be $1.5{\times}10^{-2}$. The two optical embedded gratings in BK-7 glass plate were demonstrated with refractive index modification induced by the scanning of low-density plasma formation.