• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.204.2-204.2
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• 2013

Wide band gap II-VI semiconductors have attracted the interest of many research groups during the past few years due to the possibility of their applications in light-emitting diodes and laser diodes. Among the II-VI semiconductors, ZnO is an important optoelectronic device material for use in the violet and blue regions because of its wide direct band gap (Eg ~3.37 eV) and large exciton binding energy (60 meV). F-doped ZnO (FZO) and undoped ZnO thin films were grown onto quartz substrate by the sol-gel spin-coating method. The doping level in the solution, designated by F/Zn atomic ratio of was varied from 0 to 5 in 1 steps. To investigate the effects of the structure and optical properties of FZO thin films were investigated using X-ray diffraction (XRD), UV-visible spectroscopy, and photoluminescence (PL). In the XRD, the residual stress, FWHM, bond length, and average grain size were changed with increasing the doping concentration. For the PL spectra, the high INBE/IDLE ratio of the FZO thin films doping concentration at 1 at.% than the other samples.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.6
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• pp.1931-1940
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• 1996

The effect of periodic passing wake on the film-coolant flow issuing normally from a flat plate was investigated experimentally. The passing wake was generated by rotating thin circular bars. Depending on the rotational direction the test plate could be simulated as a pressure surface or a suction surface of a gas turbine blade. The phase-averaged velocity components were measured using an X-type hot-wire probe. The Reynolds number based on the free-stream velocity and injection hole diameter was 23, 500 and the velocity ratio which is the ratio of film coolant velocity to free-stream velocity was 0.5. The velocity-triangle induced by the wake was similar to that induced by the one generated at the blade trailing edge. The vertical velocity component induced by the passing wake, which approaches to the suction surface and moves away from the pressure surface, played a dominant role in the variation of the flow field. The variation in the phase-averaged velocity on the pressure surface was greater than on the suction surface, but the turbulence kinetic energy variation on the suction surface appeared larger than on the pressure surface.

• Journal of the Korean Society of Food Culture
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• v.36 no.5
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• pp.464-473
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• 2021

Although fine dust pollution in Korea is increasing, there is no information regarding nutritional standards for fine dust-related disease patients. This study analyzed the food and nutrient intake status in adult men with disease associated with fine dust in the area with the increased level of fine dust pollution using the sixth and seventh Korea National Health and Nutrition Examination Survey (2013-2017). The daily intakes, and average nutrient adequacy ratio (NAR) and mean adequacy ratio (MAR) values of energy were significantly increased in the control group compared with patient groups. Compared with the control group, protein, fat and cholesterol intakes were significantly increased in the patient groups. Daily intakes of cereals and grain products in the control group were increased, whereas seasoning intake was decreased in the control group compared with patient groups. The patient groups had low daily water and vitamin B₁ intakes, and the niacin intake of patient groups was significantly lower than that of the control group. Nutrition density and nutritional quality of vitamin C were significantly reduced in patient groups. This study can be used as basic data for nutrition education that emphasizes sufficient calorie, water and antioxidant vitamin intakes for patients related to fine dust pollution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.3
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• pp.436-442
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• 2022

In this paper, the performance of the selective combining according to the channel selection decision method of frequency diversity is evaluated in the underwater frequency selective channel. The underwater acoustic channel in the shallow sea has a complex multipath characteristic by combining various environmental factors such as boundary surface reflection and sound wave refraction according to the water temperature layer. In particular, frequency selectivity due to multipath causes energy fluctuation in a communication channel, which reduces SNR (Signal to Noise Ratio) and deteriorates communication performance. In this paper, we applied the frequency diversity technique using multiple channels to secure the communication performance according to the frequency selectivity by multipath. For each channel, 4-FSK (Frequency Shift Keying) and selective combining were applied, the performance was evaluated by applying the maximum value, average value, and majority decision of the signal in order to decide the demodulation channel selection of the selective combining.

• Journal of Animal Science and Technology
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• v.64 no.3
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• pp.462-470
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• 2022

The addition of dietary proteases (PRO) to weaner diets hydrolyzes soybean-based anti-nutritive factors and improves weaned pig's dietary digestibility and growth performance. Therefore, this study explores the effects of PRO in a lower crude protein (CP) level diet than that in a commercial diet on the growth performance, nutrient digestibility, and intestinal morphology of weaned pigs. A total of 90 weaned pigs were randomly assigned to 3 dietary treatments with 6 pigs per pen and 5 replicated pens per treatment using a randomized complete block design (block = body weight [BW]): 1) a commercial weaner diet as a positive control (PC; phase1 CP = 23.71%; phase2 CP: 22.36%), 2) lower CP diet than PC as a negative control (NC; 0.61% less CP than PC), and 3) an NC diet with 0.02% PRO. Pigs fed PC and PRO had higher (p < 0.05) final BW, average daily gain, and/or gain to feed ratio for the first three weeks and the overall experimental period than NC. The PC and PRO groups had greater (p < 0.05) apparent ileal digestibility of dry matter, CP, and energy than the NC group. Moreover, pigs fed PC and PRO increased (p < 0.05) apparent total tract digestibility of CP compared with those fed NC. In addition, the PRO group had a higher number of goblet cells than the PC and NC groups. However, pig fed PC and PRO increased (p < 0.05) villus height and height to crypt depth ratio in the ileum compared with those fed NC. In conclusion, PRO supplementation in a commercial weaner diet with low CP levels improves growth rate and nutrient digestibility by modulating the intestinal morphology of weaned pigs.

• Steel and Composite Structures
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• v.49 no.4
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• pp.441-456
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• 2023

Aiming at the development trend of light weight and high strength of engineering structures, this paper experimentally investigated the seismic performance of circular-in-square high-strength concrete-filled double skin steel tubular (HCFDST) stub columns with out-of-code width-to-thickness (B/t) ratios. Typical failure mode of HCFDST stub columns appeared with the infill material crushing, steel fracture and local buckling of outer tubes as well as the inner buckling of inner tubes. Subsequently, the detailed analysis on hysteretic curves, skeleton curves and ductility, energy dissipation, stiffness degradation and lateral force reduction was conducted to reflect the influences of hollow ratios, axial compression ratios and infill types, e.g., increasing hollow ratio from 0.54 to 0.68 and 0.82 made a slight effect on bearing capacity compared to the ductility coefficients; the higher axial compression ratio (e.g., 0.3 versus 0.1) significantly reduced the average bearing capacity and ductility; the HCFDST column SCFST-6 filled with concrete obviously displayed the larger initial secant stiffness with a percentage 34.20% than the column SCFST-2 using engineered cementitious composite (ECC); increasing hollow ratios, axial compression ratios could accelerate the drop speed of stiffness degradation. The out-of-code HCFDST stub columns with reasonable design could behave favorable hysteretic performance. A theoretical model considering the tensile strength effect of ECC was thereafter established and verified to predict the moment-resisting capacity of HCFDST columns using ECC. The reported research on circular-in-square HCFDST stub columns can provide significant references to the structural application and design.

• Journal of Korean Society on Water Environment
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• v.40 no.2
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• pp.67-78
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• 2024

The introduction of a significant amount of phosphorous into aquatic environments can lead to eutrophication, which can in turn result in algal blooms. For the effective management of watersheds and the prevention of water quality problems related to nonpoint organic matter (OM) sources, it is essential to pinpoint the predominant OM sources. Several potential OM sources were sampled from upper agricultural watersheds, such as fallen leaves, riparian reeds, riparian plants, paddy soil, field soil, riparian soil, cow manure, and swine manure. Stream samples were collected during two storm events, and the concentrations of dissolved organic carbon (DOC) and phosphorous (DOP) from these OM sources and stream samples were assessed. DOM indicators using fluorescence spectroscopy, including HIX, FI, BIX, and EEM-PARAFAC, were evaluated in terms of their relevance in discerning DOM sources during storm events. Representative DOM descriptors were chosen based on specific criteria, such as value ranges and pronounced differences between low and high-flow periods. Consequently, the spectral slope ratio (S_R) paired with fluorescence index (FI) using end-member mixing analysis (EMMA) proved to be suitable for estimating the contribution of organic carbon (OC). The contribution of each organic phosphorous (OP) in stream samples was determined using the phosphorous-to-carbon (P/C) ratio in conjunction with the OC contribution. Notably, OP derived from swine manure in stream samples was found to make the most dominant contribution, ranging from 61.3% to 94.2% (average 78.1% ± 12.7%). The results of this research offer valuable insights into the selection of suitable indicators to recognize various OM sources and highlight the main sources of OP in forested-agricultural watersheds.

• Journal of the Korean Society of Food Culture
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• v.15 no.3
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• pp.163-174
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• 2000

This research was designed to develop a computer program and evaluate the nutritional balances especially the balance of fatty acids, amino acids and antioxidant vitamins for convenience foods. The Korean convenience food, Kimbab purchased from markets was evaluated by using the self-developed computer program. Contents of calories, protein and calcium were lower$(1/3^{\circ}{\neq}1/2)$ than the recommended levels of Korean adult woman, and the carbohydrate/ protein/ fat(CPF) energy ratio was 70: 13: 17. The mean P/ M/ S ratio was 2.2/ 1.4/ 1 and that of ${\omega}6/\;{\omega}3$ fatty acids was 17.9/ 1, which was higher than the desirable ratio of $4{\sim}8/\;1$. Average essential amino acid balance of market-Kimbab samples was within the desirable range even though the absolute amount of protein was lower than the recommended level. Contents of antioxidant vitamins (A, C &E) were lower than recommended levels. Two kinds of nutritionally adjusted Kimbab menu were established by self-developed computer program. Some of major changes was adding food ingredients such as tuna fish and perilla leaf cooked with sesame oil and soybean oil to increase ${\omega}3$ series fatty acids. Some fruits and milk were also added to the menu. The adjusted CPF ratios was 63: 15: 22 and the new values for P/ M/ S and ${\omega}6/\;{\omega}3$ fatty acids ratios were 1.0/ 1.2/ 1/0 and 6.1/ 1 respectively. In sensory evaluation of two kinds of adjusted Kimbab, the taste and overall estimation scores were higher than unadjusted Kimbab. The computer program developed in this study might be used as a tool for the evaluation of nutritional balance of other convenience foods and menu planning.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1628-1633
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• 2005

Three hundred and twenty four one day old mixed sex broiler chicks were assigned at random into 9 treatment groups. The experimental design was a 3${\times}$3 factorial arrangement. During the starter period (week 1-3), chicks were fed ad libitum. A cornsoybean meal based diet contained 23% crude protein, 3,200 kcal/kg metabolizable energy (NRC, 1994), and supplemented with organic or inorganic forms of chromium. Two organic chromium products, chromium yeast (Cr-Yeast from Alltech Biotechnology Corporation Limited) and chromium picolinate (Cr-Pic) were supplemented at the rate of 200, 400 and 800 ppb. One inorganic product, chromium chloride, was supplemented at the rate of 200, 400 and 800 ppb. During the finishing period (week 4-7), the corn-soybean meal based diet contained 20% crude protein, 3,200 kcal/kg metabolizable energy (NRC, 1994), and the same levels of chromium as in the starter period were added. No significant difference was observed among treatment groups in average daily gain, feed intake, body weight gain, feed conversion ratio and mortality. The carcass percentage of broilers receiving 200 and 400 ppb organic chromium (Cr-Yeast or Cr-Pic) was significantly increased (p<0.01). In addition, the supplementation of organic chromium reduced (p<0.05) breast meat fat content but increased breast meat protein content. The addition of chromium in the diet had no effect on boneless breast, skinless boneless breast, boneless leg, skinless boneless leg but reduced percentage of sirloin muscle. Total cholesterol and triglycerides were reduced by organic Cr supplementation. Supplementation with 200 and 400 ppb of both Cr-Yeast and Cr-Pic showed the lowest total cholesterol. The effects of type of Cr on HDL and LDL were variable, however, LDL increased with increasing level of Cr supplementation. This trial indicates that organic chromium tended to improve growth performances and carcass composition, reduced total cholesterol and triglycerides. The optimum level of organic chromium supplementation was at 200 ppb.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.3
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• pp.401-410
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• 1993

Day-old male and female broilers obtained from commercial strain (Hubbard) were used in this study. At 7 days of age, all chicks were weighed individually (female 0.11 kg and male 0.12 kg in average) and divided into 5 group of 45 birds each group with no replicate in each treatment group as follows: 1. fed ad libitum; 2. fed 75% ad libitum; 3. fed 65% ad libitum; 4. fed 55% ad libitum; 5. fed 45% ad libitum. Chicks were restricted for 10 days (d 7 through 17) of a 56-day trial. Chicks were fed a commercial starter diet (crude protein (CP) 23.8% and metabolizable energy (ME) 3,070 kcal/kg) for 21 days, and commercial finisher diet (CP 20% and ME 3,160 kcal/kg) from 22 to 56 days of age. When chicks were feed-restricted at an early age, compensatory growth did not immediately occur following refeeding. Body weights of restricted chicks were not equal to the ad libitum chicks before 49 days of age. At 56 dyas of age, body weights of restricted chicks were heavier (p<0.01). Abdominal fat values of female chicks fed ad libitum was not significantly different from those fed 45% to 75% ad libitum. Carcass fat values of restricted female chicks were lower than those of control chicks when female chicks were fed either 55% or 45% ad libitum. Furthermore, feed efficiencies of restricted chicks were better. The response of chicks to early feed restriction might depend on the degree of feed restriction, and sex. Factors contributing carcass fat included energy loss, fat protein ratio of carcass, fatty acid synthesis in the liver and triglyceride content of the liver. The heavier body weights in the restricted chicks might be correlated with the lower growth rate during period of feed restriction.