• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.612-618
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• 2023

Modern society spends more than 80% of its daily life indoors, emphasizing the need for attention to indoor air pollution due to the improvement in living standards. In this study, the performance and reaction characteristics of the Pt/TiO₂ catalysts prepared by liquid-phase reduction for the removal of formaldehyde (HCHO), one of the indoor air pollutants, at room temperature without the need for additional light or heat were investigated. As a result, it showed that catalysts prepared by the same method showed approximately 40~80% various activities depending on the type of TiO₂. XRD, BET, and XPS analyses were performed to investigate the particle size, crystal structure, specific surface area, and O/Ti molar ratio of the support material, and it revealed that the correlation between the properties and performance was insignificant. To explore the oxidation reaction pathway of formaldehyde (HCHO), in situ DRIFT analysis using carbon monoxide and H₂-TPR was perfomed. The results revealed that the performance was demonstrated by the oxidation state of the active metal and the adsorption-desorption characteristics of the adsorbate species.

• Clean Technology
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• v.29 no.4
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• pp.313-320
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• 2023

In order to increase the usability of H₂-SCR, the NOx removal characteristics with catalyst powder of PtNi/CeO₂-W-TiO₂ using Ce as a co-catalyst was synthesized and coated on a porous metal structure (PMS) were evaluated. Catalyst powder of PtNi/CeO₂-W-TiO₂(PtNi nanoparticles onto W-TiO₂, with the incorporation of ceria (CeO₂) as a co-catalysts) was synthesized and coated onto a porous metal structure (PMS) to produce a Selective Catalytic Reduction (SCR) catalyst. H₂-SCR with CeO₂ as a co-catalyst exhibited higher NOx removal efficiency compared to H₂-SCR without CeO₂. Particularly, at a 10wt% CeO₂ loading ratio, the NOx removal efficiency was highest at 90℃. As the amount of catalyst coating on PMS increased, the NOx removal efficiency was improved below 90℃, but it was decreased above 120℃. When the space velocity was changed from 4,000 h^-1 to 20,000 h^-1, the NOx removal efficiency improved at temperatures above 120℃. It was expected that the use of the catalyst could be reduced by applying the PMS with excellent specific surface area as a support.

• Animal Bioscience
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• v.37 no.2
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• pp.274-283
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• 2024

Objective: The aim of the study was to evaluate the physicochemical properties (nutrient composition, pH, water content and activity, sorption properties) and mechanical properties (compression force and energy) of granulated feed mixtures with various inclusion levels of crude fibre concentrates ARBOCEL and VITACEL for broiler chickens, i.e. +0.0% (control group - group C), +0.3%, +0.8%, +1.0%, +1.2%. Methods: The feed mixtures were analyzed for their physicochemical properties (nutrient composition by near-infrared spectroscopy, pH with the use a CP-401 pH meter with an IJ-44C glass electrode, water content was determined with the drying method and activity was determined with the Aqua Lab Series 3, sorption properties was determined with the static method) and mechanical properties (compression force and energy with the use TA-HD plus texture analyzer). The Guggenheim-Anderson-de Boer (GAB) model applied in the study correctly described the sorption properties of the analyzed feed mixtures in terms of water activity. Results: The fibre concentrate type affected the specific surface area of the adsorbent and equilibrium water content in the GAB monolayer (p≤0.05) (significantly statistical). The type and dose of the fibre concentrate influenced the dimensionless C and k parameters of the GAB model related to the properties of the monolayer and multilayers, respectively (p≤0.05). They also affected the pH value of the analyzed feed mixtures (p≤0.05). In addition, crude fibre type influenced water activity (p≤0.05) as well as compression energy (J) and compression force (N) (p≤0.001) (highly significantly statistical) of the feed mixtures. Conclusion: The physicochemical analyses of feed mixtures with various inclusion levels (0.3%, 0.8%, 1.0%, 1.2%) of crude fiber concentrates ARBOCEL or VITACEL demonstrated that both crude fiber types may be used in the feed industry as a feedstuff material to produce starter type mixtures for broiler chickens.

• Animal Bioscience
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• v.37 no.3
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• pp.500-508
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• 2024

Objective: Due to current selection practices for increased egg production and peak persistency, the production profile, age at maturity, and body weight criteria for commercial layers are constantly changing. Body weight and age at the time of photostimulation will thus always be the factors that need to be adequately addressed among various production systems. The current study was carried out to determine the effects of pullets' body weight (low, medium, and heavy) on their performance, welfare, physiological response, and hormonal profile. Methods: With regard to live weight, 150 16-week-old pullets were divided into three groups using a completely randomized design (CRD) and held until the 50th week. One-way analysis of variance was used to evaluate the data under the CRD, and the least significant difference test was used to distinguish between treatment means. Results: In comparison to the medium and light birds, the heavy birds had higher body weight at maturity, an earlier age at maturity, and higher egg weight, eggshell weight, eggshell thickness, egg yolk index, breaking strength, egg surface area, egg shape index, egg volume, and hormonal profile except corticosterone. However, the medium and light birds had lower feed consumption rates per dozen eggs and per kilogram of egg mass than the heavy birds. Light birds showed greater body weight gain, egg production, and egg specific gravity than the other categories. At 20 weeks of age, physiological response, welfare aspects, and catalase were non-significant; however, at 50 weeks of age, all these factors-aside from catalase-were extremely significant. Conclusion: The findings of this study indicate that layers can function at lower body weights during photostimulation; hence, dietary regimens that result in lighter pullets may be preferable. Additionally, the welfare of the birds was not compromised by the lighter weight group.

• Clean Technology
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• v.30 no.2
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• pp.145-156
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• 2024

Carbon has a large specific area and excellent chemical stability, so research on its use as a catalyst support is actively conducted. When using carbon as a support, the pretreatment process is essential. Through pretreatment of carbon, the growth of metal nanoparticles can be controlled and the bonding strength between the support and metal particles can be improved. In this study, carbon was pretreated for surface modification and 5 wt% Pd/C catalysts were synthesized using it as a support. Catalytic activity was evaluated through phenol hydrogenation. To compare with nitric acid, which is commonly used in carbon pretreatment, carbon pretreatment was performed using organic acid. Pd/C treated with gluconic acid showed the highest activity, with 94.93% phenol conversion and 92.76% cyclohexanone selectivity. Therefore, it is expected that pretreatment of the carbon support using organic acid will not only overcome the disadvantages of inorganic acid treatment but also improve catalyst performance.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.286-294
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• 2008

In order to understand the physical properties of deep-sea sediments, which mainly consist of pelagic red clays, sediment samples were collected at 24 stations using a multiple corer in the Clarion-Clipperton fracture zone of the northeast equatorial Pacific. The sampled sediment cores were examined for the mass physical properties(i.e. grain size distribution, mean grain size, water content, specific grain density, wet bulk density, void ratio, and porosity) and the geotechnical properties(i.e. shear strength and consistency limits) with the content of biogenic opal and mineral composition. Although KR1 and KR2 areas on the same latitude are logitudinally far from each other, the mass physical properties of these areas are not distinctly different except for shear strengths. The maximum shear strength of surface sediments in KR2 area is higher than that in KR1 due to the appearance of a consolidated lower layer(Unit 3) in the sediment core from KR2.

• Journal of Aquaculture
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• v.1 no.1
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• pp.13-24
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• 1988

In order to investigate a reasonable rearing density and the possibility of high-density rearing, flounder, Paralichthys olivaceus, juveniles of 2.53$\pm$0.24 cm in total length and 1.12$\pm$0.12 cm in body height were used in this study. The initial rearing density of them was 10 (D10), 20 (D20), 30 (D30) and 40 (D40) individuals per 137.75 $cm^2$ of bottom area, respectively. Ranges of water temperature and specific gravity during the rearing period of 65 days were $21.0\~27.0^{\circ}C$ and 1.024$\~$1.026, respectively, showing relatively higher values than that of natural sea water. Dissolved oxygen during the rearing period was 5.4$\~$7.5 ml/$\iota$ and inorganic nitrate was 0.07$\~$0.48 ppm in $NH_4^+-N$, 0.006$\~$0.33 ppm in $NO_2^{-}-N$ and 3.89$\~$34.06 ppm in $NO_3^{-}-N$. Growth in total length and body height of the juveniles in four rearing density at the end of the experiment was 8.17$\pm$0.80 em and 4.16$\pm$0.39 em, the highest in D20 and 7.72$\pm$0.40 cm and 3.94$\pm$0.21 cm, the lowest in D10. Significant differences, however, were not recognized between the slope values of growth regressions in four rearing density. Slope values of the relative growth between total length and body height of the juveniles in four rearing density were 0.5346, the highest in D10 and 0.5165, the lowest in D30, but there were no significant differences in those values. Survival rate of juveniles at the end of the experiment was $90\%$ in D10, D20 and D30, but that of D40 was $75\%$. The relationship between total length X body height (X) and body surface area of ocular side (Y) to calculate the rate of Y to bottom area in rearing tank (covering rate) as an indicator of rearing density was expressed by a linear regression, Y=0.5994X+0.1840. Covering rate in four rearing density at the end of the experiment was ranged 1.2$\~$4.1 times. Judging from the covering rate above 4 times, it seems to be possible rearing the flounder juveniles in high-density.

• The Korean Journal of Air & Space Law and Policy
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• v.31 no.2
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• pp.145-176
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• 2016

Aviation safety can be secured through regulations and policies of various areas and thorough execution of them on the field. Recently, for aviation safety management Korea is making efforts to prevent aviation accidents by taking various measures: such as selecting and promoting major strategic goals for each sector; establishing National Aviation Safety Program, including the Second Basic Plan for Aviation Policy; and improving aviation related legislations. Obstacle limitation surface is to be established and publicly notified to ensure safe take-off and landing as well as aviation safety during the circling of aircraft around airports. This study intends to review current aviation obstacle management system which was designed to make sure that buildings and structures do not exceed the height of obstacle limitation surface and identify its operating problems based on my field experience. Also, in this study, I would like to propose ways to improve the system in legal and regulatory aspects. Nowadays, due to the request of residents in the vicinity of airports, discussions and studies on aviational review are being actively carried out. Also, related ordinance and specific procedures will be established soon. However, in addition to this, I would like to propose the ways to improve shortcomings of current system caused by the lack of regulations and legislations for obstacle management. In order to execute obstacle limitation surface regulation, there has to be limits on constructing new buildings, causing real restriction for the residents living in the vicinity of airports on exercising their property rights. In this sense, it is regarded as a sensitive issue since a number of related civil complaints are filed and swift but accurate decision making is required. According to Aviation Act, currently airport operators are handling this task under the cooperation with local governments. Thus, administrative activities of local governments that have the authority to give permits for installation of buildings and structures are critically important. The law requires to carry out precise surveying of vast area and to report the outcome to the government every five years. However, there can be many problems, such as changes in the number of obstacles due to the error in the survey, or failure to apply for consultation with local governments on the exercise of construction permission. However, there is neither standards for allowable errors, preventive measures, nor penalty for the violation of appropriate procedures. As such, only follow-up measures can be taken. Nevertheless, once construction of a building is completed violating the obstacle limitation surface, practically it is difficult to take any measures, including the elimination of the building, because the owner of the building would have been following legal process for the construction by getting permit from the government. In order to address this problem, I believe penalty provision for the violation of Aviation Act needs to be added. Also, it is required to apply the same standards of allowable error stipulated in Building Act to precise surveying in the aviation field. Hence, I would like to propose the ways to improve current system in an effective manner.

• Korean Journal of Plant Taxonomy
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• v.31 no.3
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• pp.283-309
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• 2001

Acer pictum complex (A. pictum Thunb. ex Murray with varieties, A. okamotoanum Nakai, A. truncatum Bunge) in eastern Asia causes frequent difficulty in identification. One hundred twenty five specimens from A. pictum complex of China, Korea and Japan and A. cappadocicum var. sinicum of China were compared to investigate patterns of intra- and interspecific variation and to evaluate a recognition of several species as well as many varieties using 22 characters for morphometric analysis. The first three PCA accounted for 59% of the total variance. No strong discontinuities existed among taxa with respect to fruit and leaf characters. Much overlap among all taxa occurred the central region of the scatter diagram. Many characters appeared to show some clinal variation with changes from east of China to Japan through Korea. This was true not only when all species as considered as a single taxon, but when characters of individual taxa were compared with geography. As one considers a path from the western part of the ranges to areas to the east, the leaves become larger in most respects and become increasingly many lobed (five to seven or nine). In general, there was a tendency toward larger nutlet with smaller wing in the area toward northeast of China (=A. truncatum), while in the east of ranges (Island Ullung-do), plants were larger with respect to characters of fruit and leaves (=A. okamotoanum). The morphological differentiation between A. okamotoanum and Japanese and Korean individuals of A. pictum was not considered sufficient to warrant recognition of either specific or varietal status and should be treated as con specific under A. pictum var. mono. Since the lectotype of Acer pictum had minute hairs uniformly on the under surface of leaves(A. pictum var. pictum), the glabrous type of A. pictum was called A. pictum var. mono as Ohahsi suggested. The univaraite analysis (the mean and maximum/minium of nutlet size and wing/nutlet length ratio) indicated geographical differentiation of northeastern populations, A. truncatum, was distinctive, but Korean individuals of A. truncatum showed an affinity between Chinese individuals of A. truncatum and Korean individuals of A. Pictum var. mono. The current results, together with qualitative character, trunk features, justify subspecific status for this taxon. The previous varieties of A. mono in Korea were indistinguishable from typical form of A. Pictum var. mono on the basis of the wing angle and nutlet size, rejecting continued recognition of these taxa as distinctive varieties. Therefore, it is recommended that only one polymorphic species of A. pictum be recognized in addition to three varieties.

• Journal of Korean Society of Forest Science
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• v.84 no.2
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• pp.151-165
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• 1995

This study was conducted to establish a systematized taxonomic problems of through the leaf morphological characters and leaf venation patterns, and stomatal cell patterns and cell characteristics of abaxial and adaxial surface of the leaflets by SEM, of 6 native species in Korea and 2 foreign species of the Genus Rhus in the Family Anacardiaceae. The results obtained from this study are summarized as followings: 1. Morphological study measured 32 characters of leaves from herbarium specimen and field-collected samples for each species. The results of cluster analysis based on the Euclidean distance showed that the species could be classified into 3 groups: R. sylvestris. R. typhina, R. succedanea: R. trichocarpa. R. chinensis. R. verniciflua: and R. ambigua. R. radicans subsp. orientale, Analysis of principal components showed 5 groups: The major factors in the first principal component group was length of petiole of the terminal leaflets, that in the second group angle of left side in the terminal leaflet bash, that in the third group area ratio between first and terminal leaflets, that in the forth group angle ratio between right and left side in the terminal leaflet base, and that in the fifth group was angle of main and secondary vein at midrib of terminal leaflet. Cumulative contribution by the first, second and third principal component group was explained with 82.6%, a large percent of all information. 2. The leaf venation pattern investigated using soft X-ray photography revealed clado-and reticulo-camptodromous types according to branching angle of the secondary vein. And three groups by the developing degree of secondary vein were R. trichocarpa, R. ambigua. R. chinensis, R. typhina; R. radicans subsp. onentale, R. succedanea, R. verniciflua: and R. sylvestris. Classification key for the Rhus of Korean-native Anacardiaceae was made by the venation pattern and devevoping degree of the secondary vein. 3. The stomatal cell patterns were greatly classified into paracytic and anomocytic types, specific among species according to stomatal and subsidiary cell patterns, and various differences among the species was determined. Microstructure of the adaxial and abaxial surfaces could be divided into synclinal and anticlinal cell wall patterns, and were specific-species. Stomatal cells of R. chinensis were surrounded with characterized villus-like cells.