• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.177-184
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• 2021

Sex identification in day-old chicks is essential in the poultry industry. Currently, the feather-sexing using a sex-linked inheritance is a chick sexing method used extensively in the poultry industry. For chicks produced by feather-sexing, all females are early-feathering (EF) chicks and all males are late-feathering (LF) chicks. Therefore, investigating the effects of EF and LF phenotypes on production traits of chickens is critical. The purpose of this study was to analyze and compare the production performance between EF and LF chickens in Korean native commercial chickens. The results showed that the survival rate of the EF chickens was significantly higher than that of the LF chickens, from hatching to 12 weeks of age (P<0.05), with the highest difference observed in females. However, no significant difference was observed in body weight between the EF and LF chickens at almost all ages. In addition, no significant difference was observed between in feed utility, such as average daily feed intake and feed conversion ratio, between the EF and LF groups. In conclusion, although the survival rate of early-feathering chickens was superior to that of late-feathering chickens, no significant difference was observed in growth performance and feed utility among Korean native chickens. The results suggest that production capacity is not influenced by feathering type in the establishment of a breeder structure and production system for feather-sexing Korean native chickens, which is valuable for the practical application of feather-sexing in the poultry industry.

• Journal of Animal Science and Technology
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• v.64 no.5
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• pp.985-996
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• 2022

This study investigated the effects of light intensity on growth performance, blood components, eye condition, and carcass characteristics of broiler chickens. Three hundred and fifty-two 1-day-old male chicks were assigned to one of four treatments (four repetitions per treatment, 22 birds per repetition) and reared in a floor pen for 5 weeks. From the second week, chicks were reared under four different levels of light intensity (5, 20, 35, and 50 lx) and the lighting duration was maintained at 18-hours light : 6-hours dark (18L : 6D). The feed intake and body weight were measured weekly. At 35 days of age, 12 birds per treatment were randomly selected for blood sampling, eye measurement, and carcass analysis. There were no significant differences in body weight gain, feed intake, and feed conversion ratio among treatments. Triglyceride levels in the serum were significantly higher in the 5 lx treatment, and creatinine was significantly lower in the 5 lx treatment (p < 0.05). The heterophil : lymphocyte ratios decreased significantly as light intensity increased (p < 0.05); however, other blood cell compositions were not affected by light intensity. Interleukin-6 content was significantly higher in the 5 lx treatment than in other treatments (p < 0.05), but the content of tumor necrosis factor-α was not significantly different among treatments. Serum corticosterone concentration was significantly higher at 5 lx than at 20, 35, and 50 lx (p < 0.05). The corneal diameter was the highest in 5 lx treatment (p < 0.05), and tended to increase as the light intensity decreased. Other eye parameters were not significantly different among treatments, but displayed a tendency to increase as the light intensity decreased. Carcass yield and part yields were not affected by light intensity. Meat quality parameters (pH, color, cooking loss, and water-holding capacity) did not show significant difference among the treatments. The results indicate that a light intensity of 5 lx may increase physiological stress or have a negative effect on broiler welfare, even if the performance and carcass characteristics are not affected. Therefore, a light intensity of 20 lx or above is recommended considering both the growth performance and welfare of broilers.

• Membrane Journal
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• v.32 no.5
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• pp.292-303
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• 2022

An eco-friendly energy conversion device without the emission of pollutants has gained much attention due to the rapid use of fossil fuels inducing carbon dioxide emissions ever since the first industrial revolution in the 18th century. Polymer electrolyte membrane fuel cells (PEMFCs) that can produce water during the reaction without the emission of carbon dioxide are promising devices for automotive and residential applications. As a key component of PEMFCs, polymer electrolyte membranes (PEMs) need to have high proton conductivity and physicochemical stability during the operation. Currently, perfluorinated sulfonic acid-based PEMs (PFSA-PEMs) have been commercialized and utilized in PEMFC systems. Although the PFSA-PEMs are found to meet these criteria, there is an ongoing need to improve these further, to be useful in practical PEMFC operation. In addition, the well-known drawbacks of PFSA-PEMs including low glass transition temperature and high gas crossover need to be improved. Therefore, this review focused on recent trends in the development of high-performance PFSA-PEMs in three different ways. First, control of the side chain of PFSA copolymers can effectively improve the proton conductivity and thermal stability by increasing the ion exchange capacity and polymer crystallinity. Second, the development of composite-type PFSA-PEMs is an effective way to improve proton conductivity and physical stability by incorporating organic/inorganic additives. Finally, the incorporation of porous substrates is also a promising way to develop a thin pore-filling membrane showing low membrane resistance and outstanding durability.

• Journal of the Korean Electrochemical Society
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• v.26 no.1
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• pp.11-18
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• 2023

As the use of lithium-ion secondary batteries is rapidly increasing due to the rapid growth of the electric vehicle market, the disposal and recycling of spent batteries after use has been raised as a serious problem. Since stored energy must be removed in order to recycle the spent batteries, an effective discharging process is required. In this study, graphite and NCM622 were used as active materials to manufacture coin-type half cells and full cells, and the electrochemical behavior occurring during overdischarge was analyzed. When the positive and negative electrodes are overdischarged respectively using a half-cell, a conversion reaction in which transition metal oxide is reduced to metal occurs first in the positive electrode, and a side reaction in which Cu, the current collector, is corroded following decomposition of the SEI film occurs in the negative electrode. In addition, a side reaction during overdischarge is difficult to occur because a large polarization at the initial stage is required. When the full cell is overdischarged, the cell reaches 0 V and the overdischarge ends with almost no side reaction due to this large polarization. However, if the full cell whose capacity is degraded due to the cycle is overdischarged, corrosion of the Cu current collector occurs in the negative electrode. Therefore, cycled cell requires an appropriate treatment process because its electrochemical behavior during overdischarge is different from that of a fresh cell.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.149-155
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• 2023

Photovoltaic power generation is the most familiar power generation facility among new and renewable energies, and its supply began to expand about 10 years ago, and at this point, interest in solutions and technologies for system maintenance management is increasing. In particular, it is necessary to take measures to maximize the overall efficiency of the solar power generation system, whether or not there is an abnormality in the solar power generation system, and when to replace parts. The PV inverter, one element of the photovoltaic power generation system, is a power conversion system that relies on power switching devices, and DC-Link capacitors are used according to the configuration of DC/DC converters and DC-AC inverters. These DC capacitors also affect system safety (Safety) through renewable energy facilities due to the decrease in power generation of PV inverters, power loss, and increase in harmonics (THD, total distortion of AC output current) due to aging and deterioration due to long-term use. factors can be analyzed. Therefore, in this paper, the PV inverter operating characteristics according to the DC capacitor capacity state currently operating in the photovoltaic power generation system were considered, and research contents were proposed to secure the safety and reliability of renewable energy facilities.

• Animal Bioscience
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• v.36 no.8
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• pp.1241-1251
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• 2023

Objective: Egg yolk immunoglobulin (IgY) is an antibiotic alternative to prevent and fight intestinal pathogenic infections. This study aimed to investigate the effects of sodium alginate/chitosan/sodium alginate IgY microcapsules on the growth performance, serum parameters, and intestinal health of broiler chickens. Methods: One-day-old broilers (Ross 308) were divided into five treatments, each with 10 replicates of five chickens. The dietary treatments were maintained for 28 days and consisted of a basal diet (NC), basal diet + 500 mg chlortetracycline/kg diet (CH), basal diet + 50 mg non-microencapsulated IgY/kg diet (NM), basal diet + 600 mg low levels microencapsulated IgY/kg diet (LM), and basal diet + 700 mg high levels microencapsulated IgY/kg diet (HM). Results: Throughout the 28-day trial period, the NM, LM, HM, and CH groups increased average daily gain compared with the NC group (p<0.05), and the HM group reduced feed conversion ratio compared with the CH group (p<0.05). The LM and HM groups increased relative organ weights of thymus and spleen compared with the CH and NM groups (p<0.05). The HM group improved the duodenal, jejunal and ileum villi height (VH) and villus height to crypt depth ratio (VH:CD) compared with the CH and NM groups (p<0.05). Compared with the CH group, the HM group increased serum immunoglobulin (IgA), immunoglobulin G (IgG), superoxide dismutase, total antioxidant capacity, and glutathione peroxidase levels (p<0.05), and decreased serum malondialdehyde levels (p<0.05). Compared with the NC group, the NM, LM, HM, and CH groups reduced colonic Escherichia coli and Salmonella levels (p<0.05). and the HM group promoted the levels of lactic acid bacteria and bifidobacteria compared with the CH group (p<0.05). Conclusion: Microencapsulation could be considered as a way to improve the efficiency of IgY. The 700 mg high levels microencapsulated IgY/kg diet could potentially be used as an alternative to antibiotics to improve the immune performance and intestinal health, leading to better performance of broiler chickens.

• Clean Technology
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• v.30 no.2
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• pp.113-122
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• 2024

In order to better understand carbon dioxide recycling, the carbon dioxide capture characteristics of six different alkaline industrial by-products, including incineration ash, desulfurized gypsum, low-grade quicklime, and steelmaking slag were investigated using a laboratory-scale direct aqueous carbonation reactor. In addition to the dissolution characteristics of each sample, the main reaction structure was confirmed through thermogravimetric analysis before and after the reaction, and the reactive CaO content was also defined through thermogravimetric analysis. The carbon dioxide capture capacity and efficiency of quicklime were determined to be 473 g/kg and 86.9%, respectively, and desulfurized gypsum and incineration ash were also evaluated to be relatively high at 51.1 to 131.7 g/kg and 51.2 to 87.7%, respectively. On the other hand, the capture efficiency of steelmaking slag was found to be less than 10% due to the influence of the production and post-cooling conditions. Therefore, in order to apply the carbonation process to steelmaking slag, it is necessary to optimize the slag production conditions. Through this study, it was confirmed that the carbon dioxide capture characteristics of incineration ash, quicklime, and desulfurized gypsum are at levels suitable for carbonation processes. Furthermore, this study was able to secure basic data for resource development technology that utilize carbon dioxide conversion to produce calcium carbonate for construction materials.

• Korean Journal of Organic Agriculture
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• v.13 no.4
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• pp.401-412
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• 2005

This study was conducted to examine the effects of dietary Mogchotan(the mixture of charcoal and pyroligneous acid, 80:20, w/w) supplementation on fattening performance, fatty acid composition and the physico-chemical characteristics of meat in pigs. The present study was also stressed to investigate the possibility of industrial utilization of charcoal and pyroligneous acid as a livestock feed additive. Weight gain and feed conversion in pigs fed the Mogchotan supplemented diet were higher than those of the control group. In fatty acids composition, palmitic acid(C16:0) contents of Mogchotan treatment groups were lower than that of control group. However, Mogchotan supplementation increased C16:1, C18:0, C18:1, C18:2 and C18:3 contents when compared with control group pigs. Also, Mogchotan supplementation groups decreased saturated fatty acids level than control group. On the other hand, Mogchotan supplementation showed higher unsaturated fatty acids value, especially polyunsaturated fatty acids value compared to control group. The carcass pH of pigs fed the Mogchotan tended to be higher than control, but was not significantly different. The water holding capacity was significantly higher in pigs fed the 3.0% Mogchotan-supplemented diet than those of other treatment groups(p<0.05). Altogether, it has been suggested that dietary $1{\sim}3%$ of Mogchotan supplementation improved the fattening performance and meat quality in pigs.

• Journal of Intelligence and Information Systems
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• v.27 no.1
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• pp.1-21
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• 2021

As the global business environment changes, uncertainties in technology development and market needs increase, and competition among companies intensifies, interests and demands for R&D activities of individual companies are increasing. In order to cope with these environmental changes, R&D companies are strengthening R&D investment as one of the means to enhance the qualitative competitiveness of R&D while paying more attention to facility investment. As a result, facilities or R&D investment elements are inevitably a burden for R&D companies to bear future uncertainties. It is true that the management strategy of increasing investment in R&D as a means of enhancing R&D capability is highly uncertain in terms of corporate performance. In this study, the structural factors that influence the R&D capabilities of companies are explored in terms of technology management capabilities, R&D capabilities, and corporate classification attributes by utilizing data mining techniques, and the characteristics these individual factors present according to the level of R&D capabilities are analyzed. This study also showed cluster analysis and experimental results based on evidence data for all domestic R&D companies, and is expected to provide important implications for corporate management strategies to enhance R&D capabilities of individual companies. For each of the three viewpoints, detailed evaluation indexes were composed of 7, 2, and 4, respectively, to quantitatively measure individual levels in the corresponding area. In the case of technology management capability and R&D capability, the sub-item evaluation indexes that are being used by current domestic technology evaluation agencies were referenced, and the final detailed evaluation index was newly constructed in consideration of whether data could be obtained quantitatively. In the case of corporate classification attributes, the most basic corporate classification profile information is considered. In particular, in order to grasp the homogeneity of the R&D competency level, a comprehensive score for each company was given using detailed evaluation indicators of technology management capability and R&D capability, and the competency level was classified into five grades and compared with the cluster analysis results. In order to give the meaning according to the comparative evaluation between the analyzed cluster and the competency level grade, the clusters with high and low trends in R&D competency level were searched for each cluster. Afterwards, characteristics according to detailed evaluation indicators were analyzed in the cluster. Through this method of conducting research, two groups with high R&D competency and one with low level of R&D competency were analyzed, and the remaining two clusters were similar with almost high incidence. As a result, in this study, individual characteristics according to detailed evaluation indexes were analyzed for two clusters with high competency level and one cluster with low competency level. The implications of the results of this study are that the faster the replacement cycle of professional managers who can effectively respond to changes in technology and market demand, the more likely they will contribute to enhancing R&D capabilities. In the case of a private company, it is necessary to increase the intensity of input of R&D capabilities by enhancing the sense of belonging of R&D personnel to the company through conversion to a corporate company, and to provide the accuracy of responsibility and authority through the organization of the team unit. Since the number of technical commercialization achievements and technology certifications are occurring both in the case of contributing to capacity improvement and in case of not, it was confirmed that there is a limit in reviewing it as an important factor for enhancing R&D capacity from the perspective of management. Lastly, the experience of utility model filing was identified as a factor that has an important influence on R&D capability, and it was confirmed the need to provide motivation to encourage utility model filings in order to enhance R&D capability. As such, the results of this study are expected to provide important implications for corporate management strategies to enhance individual companies' R&D capabilities.

• Journal of Aquaculture
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• v.1 no.1
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• pp.67-73
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• 1988

A growth experiment of tilapia (offsprings of the hybrid between Oreochromis niloticus and O. mossambicus) under different dissolved oxygen levels in the recirculating water system was conducted at the Fish Culture Experiment Station of the National Fisheries University of Pusan from February 4 to March 5, 1986. Six tanks with a capacity of $1.8m^3$ of water each were used under the same condition of water parameters except for dissolved oxygen levels which were designated to maintain at 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 mg/$\iota$. Each tank was stocked with 90 kg of fish each averaging 64 to 69 grams. The average water temperature during the course of the experiment was $22.5^{\circ}C$. The results obtained are summarized as follows: The food conversion efficiencies were very good, being 1.05-1.11 at 3.5, 3.0, 2.5 and 2.0 mg/$\iota$ DO levels without any significant differences among them, but at 4.0 mg/$\iota$ the F. C. was 1.39 and at 1.5 mg/$\iota$ it was 1.61 being very poor compared with the others. The daily growth rate performance was best at 3.5 mg/$\iota$ dissolved oxygen level followed by 3.0 and 2.5 mg/$\iota$ with slight differences while at 4.0 and 2.0 mg/$\iota$ DO levels the growths were significantly poor, and at 1.5 mg/$\iota$ DO level it was extremely poor. In 1.5 mg/$\iota$ group, the fish did not accept feed vigorously and after feeding the fish usually concentrated around the inflow point showing oxygen deficiency response. While at 4.0 mg/$\iota$ high feeding rates tended to waste significant amounts of feed while eating and led to water deterioration, and above these levels the results is considered to lead to a waste of energy with uneconomical performance. On the other hand, at and below 2.0 mg/$\iota$ DO level the tilapia certainly showed a poor growth performance. The experiment indicates that the DO range of 2.5$\~$3.5 mg/$\iota$ is the optimum level for the good growth performance.