• Journal of the Korean Vacuum Society
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• v.20 no.6
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• pp.436-441
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• 2011

Metal coating with several nanometer thickness was applied on the carbon nanotubes (CNTs) in order to improve electron emission characteristics and emission reliability for the potential applications in the area of various electron sources and displays. CNTs were grown on the 2-nm thick Invar (52% Fe, 42% Ni, 6% Co alloy)-catalized Si substrate by using plasma-enhanced chemical vapor deposition at $450^{\circ}C$. In order to reduce the spatial density of densely packed CNTs, as-grown CNTs were partly etched back by $N_2$ plasma and subsequently coated with 5~150 nm thick Ti by a sputtering method. 5 nm thick Ti-coated CNTs produced four times higher emission current density at the electric field of 6 V/${\mu}m$ and much lower emission current fluctuation, compared with the as-grown CNTs. These improved emission properties are mainly due to not only the work function of Ti (4.3 eV) lower than that of pristine CNTs (5 eV), but also lower contact resistance and better adhesion between CNT emitters and substrate accomplished by Ti coating.

• Journal of Nutrition and Health
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• v.36 no.10
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• pp.1052-1060
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• 2003

Poor dietary habits and inadequate nutrient intakes are of concern in the elderly, even it is worse in rural areas. In the present study, we conducted the anthropometric measurement and the dietary intakes including macronutrients, minerals and vitamins to assess the nutrient intakes and nutritional risk in elderly people in rural kyungpook province in South Korea. Subjects (n = 168, mean age, 67.3 yrs) were interviewed using d general questionnaire and 3 days of 24-hours recall for dietary intake. Nutrient intakes were analyzed using CAN-pro soft program and compared to Korean RDA and nutrition reference values (NRV). The anthropometric measurement showed that the weight and the height of the subjects in the rural area were below the average of the same age of Korean elderly people. The energy and protein intakes were 85％ and 90％ of Korean RDA, respectively. The intakes of lipid, cholesterol and dietary fiber were 62％, 40％ and 22％ of NRV for Korean adults. Main sources for protein and lipid intakes came from the vegetable sources and this pattern was more prominent in female elderly people. Ca intake was half of Korean RDA (56％), while P intake was 132％ of Korean RDA. For the antioxidant trace mineral (Fe, Cu, Mn, Zn, and Se) intakes, Fe and Zn intakes were 78％ and > 103％ of Korean RDA. Cu, Mn and Se intakes were > 113％, > 275％, and > 185％ of Korean NRV. Thiamin, niacin and vitamin C intakes were above Korean RDA, but the intakes of vitamin A and riboflavin were 88％ and 63％ of Korean RDA, respectively. On summarizing the results of the present study, the elderly people in rural area consume less lipid, cholesterol, Ca, and dietary fiber. Ca intake is lower, while P intake is higher, and this would be the potential risk for bone health. Also, Na intake was high, which can be the potential risk for the cardiovascular disease prevailance. Vitamin intakes were fairly good status, excepting riboflavin. Antioxidant mineral intakes were much higher than Korean NRV, unexpectedly. The results suggest that the elderly people in rural area have inadequate intakes of protein, lipid, dietary fiber and Ca, which mainly should be supplied from animal products. Recommendations to increase diet variety would be emphasized for this nutritionally poor-conditioned subjects, specially including animal food products and high dietary fiber food.

• Clean Technology
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• v.25 no.1
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• pp.14-18
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• 2019

In general after the etching process, waste etching solution contains metals. (ex. Nickel (Ni), Chromium (Cr), Zinc (Zn), etc.) In this work, we proposed a recycling process for waste etching solution and refining from waste liquid contained nickel to make nickel metal nano powder. At first, the neutralization agent was experimentally selected through the hydrolysis of impurities such as iron by adjusting the pH. We selected sodium hydroxide solution as a neutralizing agent, and removed impurities such as iron by pH = 4. And then, metal ions (ex. Manganese (Mn) and Zinc (Zn), etc.) remain as impurities were refined by D2EHPA (Di-(2-ethylhexyl) phosphoric acid). The nickel powders were synthesized by liquid phase reduction method with hydrazine ($N_2H_4$) and sodium hydroxide (NaOH). The resulting nickel chloride solution and nickel metal powder has high purity ( > 99%). The purity of nickel chloride solution and nickel nano powders were measured by EDTA (ethylenediaminetetraacetic) titration method with ICP-OES (inductively coupled plasma optical emission spectrometer). FE-SEM (field emission scanning electron microscopy) was used to investigate the morphology, particle size and crystal structure of the nickel metal nano powder. The structural properties of the nickel nano powder were characterized by XRD (X-ray diffraction) and TEM (transmission electron microscopy).

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.249-256
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• 2019

Objective: The present study aimed at comparing the nutritional composition and color traits between two meat types: Horse meat and pork from Korean native black pigs raised in Jeju Island. Methods: After slaughter 24 h, the longissimus dorsi samples were taken from left side carcasses of the 32-mo-old Jeju female breed horses and the 6-mo-old Korean native black pigs (n = 10 each). The samples were then placed into cool boxes containing ice packs and transported to the Laboratory of Meat Science where all visual fats and connective tissues were trimmed off and then the samples were ground. All the samples were analyzed for nutritional composition (proximate composition, minerals, vitamins, fatty acids, and amino acids) and color traits. Results: The horse meat contained significantly higher collagen, moisture and protein than the pork (p<0.05). The Jeju horse meat showed more desirable fatty acid profiles such as containing significantly lower saturated fatty acids (SFA), higher polyunsaturated fatty acids (PUFA) contents and PUFA/SFA ratios than the pork (p<0.05). Differences in concentrations of ten amino acids existed between the two meat types in which the horse meat had higher values for all these amino acids, total amino acids (20.33 g/100 g) and essential amino acids (10.06 g/100 g) than the pork (p<0.05). Also, the horse meat showed significantly higher concentrations of Fe (34.21 mg/100 g) and Cu (2.47 mg/100 g) than the pork (Fe, 17.42 mg/100 g and Cu, 1.51 mg/100 g) (p<0.05). All the vitamins detected showed statistical differences between the two meat types in which the horse meat had higher concentrations of vitamin B1 (25.19 mg/100 g), B2 (92.32 mg/100 g), B3 (2,115.51 mg/100 g), and B5 (67.13 mg/100 g) than the pork (p<0.05). Conclusion: Based on the results obtained in the study, it is concluded that the two meat types studied are rich in nutrients and the animal species strongly affected the nutritional values and color traits of the muscle tissues.

• Food Science of Animal Resources
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• v.31 no.6
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• pp.935-943
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• 2011

This study was conducted to investigate the proximate composition, meat color, Warner-Bratzler shear force (WBS), cooking loss (CL), fatty acids composition, amino acid composition and mineral contents of Hanwoo beef (QG $1^+$, 1) and imported New Zealand black Angus beef with loin, strip loin, eye of round and chuck tender. The intramuscular fat contents were higher in the strip loin, loin and chuck tender of Hanwoo beef than New Zealand beef (p<0.05). Hanwoo QG 1 beef had higher Fe contents in the strip loin (30.52 mg/100g) and chuck tender (40.70 mg/100g) (p<0.05). Hanwoo beef had lower cooking loss and than those of New Zealand beef, whereas New Zealand beef had higher protein and amino acids contents (%) than their counterpart. There was no significant difference in the WBS between two origin samples except the chuck Hanwoo beef had significantly lower saturated fatty acids (SFA) and higher monounsaturated fatty acids contents than New Zealand beef (p<0.05). WBS values indicated that Hanwoo and New Zealand beef had similar tenderness in the loin, striploin and eye of round due to the longer aging periods of the New Zealand beef than Hanwoo beef during the distribution.

• Korean Journal of Environmental Agriculture
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• v.25 no.3
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• pp.217-227
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• 2006

Micronutrient status in soils and crops of plastic film house and their relationship were investigated. Total 203 plastic film houses were selected (red pepper, 66; cucumber, 63; tomato, 74) in Yeongnam region and soil and leaf samples were collected. Hot-water extractable B and 0.1 N HCl extractable Cu, Zn, Fe, and Mn in soil samples and total micronutrients in leaf samples were analyzed. Contents Zn, Fe, and Mn in most of the investigated soils were higher than the upper limits of optimum level for general crop cultivation. Contents of Cu in most soils of cucumber and tomato cultivation were higher than the upper limit of optimum level, but Cu contents in about 30% of red pepper cultivation soils were below the sufficient level. Contents of B in most soils of cucumber and tomato were above the sufficient level but in 48% of red pepper cultivation soils B were found to be deficient. Micronutrient contents in leaf of investigated crops were much variable. Contents of B, Fe, and Mn were mostly within the sufficient levels, while in 71% of red pepper samples Cu was under deficient level and in 44% of cucumber samples Cu contents were higher than the upper limit of sufficient level. Contents of Zn in red pepper and cucumber samples were mostly within the sufficient level but in 62% of tomato samples Zn contents were under deficient condition. However, any visible deficiency or toxicity symptoms of micronutrients were not found in the crops. No consistent relationships were found between micronutrient contents in soil and leaf, and this indicates that growth and absorption activity of root and interactions among the nutrients in soil might be important factors in overall micronutrient uptake of crops. For best management of micronutrients in plastic film house, much attention should be focused on the management of soil and plant characteristics which control the micronutrient uptake of crops.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.149-158
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• 2002

For the purpose of preciously describing real time traffic pattern in urban road network, dynamic network loading(DNL) models able to simulate traffic behavior are required. A number of different methods are available, including macroscopic, microscopic dynamic network models, as well as analytical model. Equivalency minimization problem and Variation inequality problem are the analytical models, which include explicit mathematical travel cost function for describing traffic behaviors on the network. While microscopic simulation models move vehicles according to behavioral car-following and cell-transmission. However, DNL models embedding such travel time function have some limitations ; analytical model has lacking of describing traffic characteristics such as relations between flow and speed, between speed and density Microscopic simulation models are the most detailed and realistic, but they are difficult to calibrate and may not be the most practical tools for large-scale networks. To cope with such problems, this paper develops a new DNL model appropriate for dynamic traffic assignment(DTA), The model is combined with vertical queue model representing vehicles as vertical queues at the end of links. In order to compare and to assess the model, we use a contrived example network. From the numerical results, we found that the DNL model presented in the paper were able to describe traffic characteristics with reasonable amount of computing time. The model also showed good relationship between travel time and traffic flow and expressed the feature of backward turn at near capacity.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.3
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• pp.290-297
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• 2008

STATEMENT OF PROBLEM: Implant-supported fixed cantilever prostheses are influenced by various biomechanical factors. The information that shows the effect of implant number and position of cantilever on stress in the supporting bone is limited. PURPOSE: The purpose of this study was to investigate the effect of implant number variation and the effect of 2 different cantilever types on stress distribution in the supporting bone, using 3-dimensional finite element analysis. MATERIAL AND METHODS: A 3-D FE model of a mandibular section of bone with a missing second premolar, first molar, and second molar was developed. $4.1{\times}10$ mm screw-type dental implant was selected. 4.0 mm height solid abutments were fixed over all implant fixtures. Type III gold alloy was selected for implant-supported fixed prostheses. For mesial cantilever test, model 1-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 1-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 1-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with mesial cantilever were simulated. And then, 155N oblique force was applied to the buccal cusp of second premolar. For distal cantilever test, model 2-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 2-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 2-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with distal cantilever were simulated. And then, 206N oblique force was applied to the buccal cusp of second premolar. The implant and superstructure were simulated in finite element software(Pro/Engineer wildfire 2.0). The stress values were observed with the maximum von Mises stresses. RESULTS: Among the models without a cantilever, model 1-1 and 2-1 which had three implants, showed lower stress than model 1-2 and 2-2 which had two implants. Although model 2-1 was applied with 206N, it showed lower stress than model 1-2 which was applied with 155N. In models that implant positions of models were same, the amount of applied occlusal load largely influenced the maximum von Mises stress. Model 1-1, 1-2 and 1-3, which were loaded with 155N, showed less stress than corresponding model 2-1, 2-2 and 2- 3 which were loaded with 206N. For the same number of implants, the existence of a cantilever induced the obvious increase of maximum stress. Model 1-3 and 2-3 which had a cantilever, showed much higher stress than the others which had no cantilever. In all models, the von Mises stresses were concentrated at the cortical bone around the cervical region of the implants. Meanwhile, in model 1-1, 1-2 and 1-3, which were loaded on second premolar position, the first premolar participated in stress distribution. First premolars of model 2-1, 2-2 and 2-3 did not participate in stress distribution. CONCLUSION: 1. The more implants supported, the less stress was induced, regardless of applied occlusal loads. 2. The maximum von Mises stress in the bone of the implant-supported three unit fixed dental prosthesis with a mesial cantilever was 1.38 times that with a central pontic. The maximum von Mises stress in the bone of the implant-supported three-unit fixed dental prosthesis with a distal cantilever was 1.59 times that with a central pontic. 3. A distal cantilever induced larger stress in the bone than a mesial cantilever. 4. A adjacent tooth which contacts implant-supported fixed prosthesis participated in the stress distribution.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.403-414
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• 2004

In the accompanying paper, we proposed a real. time volumetric imaging method using a cross array based on receive dynamic focusing and synthetic aperture focusing along lateral and elevational directions, respetively. But synthetic aperture methods using spherical waves are subject to beam spreading with increasing depth due to the wave diffraction phenomenon. Moreover, since the proposed method uses only one element for each transmission, it has a limited transmit power. To overcome these limitations, we propose a new real. time volumetric imaging method using cross arrays based on synthetic aperture technique with linear wave fronts. In the proposed method, linear wave fronts having different angles on the horizontal plane is transmitted successively from all transmit array elements. On receive, by employing the conventional dynamic focusing and synthetic aperture methods along lateral and elevational directions, respectively, ultrasound waves can be focused effectively at all imaging points. Mathematical analysis and computer simulation results show that the proposed method can provide uniform elevational resolution over a large depth of field. Especially, since the new method can construct a volume image with a limited number of transmit receive events using a full transmit aperture, it is suitable for real-time 3D imaging with high transmit power and volume rate.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.267-274
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• 2022

Excess nitrogen (N) flowing from livestock manure to water systems poses a serious threat to the natural environment. Thus, livestock wastewater management has recently drawn attention to this related field. This study first attempted to obtain the optimal conditions for the further volatilization of NH₃ gas generated from pig wastewater by adjusting the amount of injected magnesia (MgO). At 0.8 wt.% of MgO (by pig wastewater weight), the volatility rate of NH₃ increased to 75.5% after a day of aeration compared to untreated samples (pig wastewater itself). This phenomenon was attributed to increases in the pH of pig wastewater as MgO dissolved in it, increasing the volatilization efficiency of NH₃. The initial pH of pig wastewater was 8.4, and the pH was 9.2 when MgO was added up to 0.8 wt.%. Second, the residual ammonia nitrogen (NH₄⁺-N) in pig wastewater was removed by precipitation in the form of struvite (NH₄MgPO₄·6H₂O) by adjusting the pH after adding MgO and H₃PO₄. Struvite produced in the pig wastewater was identified by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analysis. White precipitates began to form at pH 6, and the higher the pH, the lower the concentration of NH₄⁺-N in pig wastewater. Of the total 86.1% of NH₄⁺-N removed, 62.4% was achieved at pH 6, which was the highest removal rate. Furthermore, how struvite changes with pH was investigated. Under conditions of pH 11 or higher, the synthesized struvite was completely decomposed. The yield of struvite in the precipitate was determined to be between 68% and 84% through a variety of analyses.