• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.271-278
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• 2021

Azolla is a genus of small aquatic ferns native to Asia, Africa, and America. Azolla is potentially significant as a nitrogen source in agriculture, particularly in conjunction with rice (Oryza sativa L.) cultivation. In addition, Azolla may either control weeds or act as a weed depending on management; therefore, we aimed to determine the effect of Azolla incorporation on weed (e.g., Monochoria vaginalis, Rotala indica, Aeschynomene indica, and Cyperus amuricus) control and its other benefits during rice cultivation. The effects of Azolla on weed emergence were evaluated based on plot area coverage by the Azolla mat, which appears as a green sheet over water, and the rate of weed emergence in paddy field. Weed occurrence was investigated 40 days after Azolla inoculation. Soil samples from the experimental plots were collected following harvest in 2014-2015, and analyzed. Moreover, rice growth, yield, and grain quality were measured. Azolla suppressed weed growth by 72%. Azolla mat incorporation in rice fields suppressed weed growth by over 60%. In addition, Azolla promoted nitrogen fixation. Compared with nitrogen management using chemical fertilizers, Azolla incorporation showed the potential for various positive effects, including the improvement of soil fertility by increasing total nitrogen, and organic matter content. Rice grown with Azolla maintained its yield without additional herbicide treatment. Moreover, the palatability of cooked rice was better when grown with Azolla.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.429-435
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• 2021

The integrated underground space map shows the underground facility(water supply, sewage, gas, electric power, communication, heating), underground structures (subway, underpass, underground walkway, underground parking lot, underground shopping mall, common ward), ground(drilling, coffin, geology) refers to a map constructed so that a total of 15 types of underground information can be checked at a glance on a three-dimensional basis. The purpose of this study is to develop a technology to correct the problem of curved surface processing and the unevenness of underground facility pipelines that occur in converting 2D underground facility data into 3D-based underground space integrated map(3D underground facility model). do it with. To this end, we first investigated and reviewed the domestic and foreign status of technologies that generate data on underground facilities based on three dimensions, and developed a surface correction algorithm and an unevenness correction algorithm to solve practical problems. Algorithms to verify the developed algorithm This applied correction program was developed. Based on the above process, the three-dimensional model of the underground facility could be produced identically to reality. This study is judged to have significance as a basic study to improve the utilization of the underground spatial integration map.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.5
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• pp.413-419
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• 2022

As the development of the underground space becomes active, safety accidents related to the underground are frequently occurring in recent years. In this regard, the Ministry of Land, Infrastructure and Transport is enforcing the 『Special Act on Underground Safety Management』 (enforced on January 1, 2018, hereafter referred to as the Underground Safety Act). Among the core contents of the Underground Safety Act, underground facilities(water supply, sewage, gas, power, communication, heating) buried underground, underground structures(subway, underpass, underpass, underground parking lot, underground shopping mall, common area), ground (Drilling, wells, geology) of 15 types of underground information can be checked at a glance on a three-dimensional basis by constructing an integrated underground spatial map and using it. The purpose of this study is to develop a program that can quickly inspect the three-dimensional model after creating a three-dimensional underground structure data among the underground spatial integration maps. To this end, we first investigated and reviewed the domestic and foreign status of technology that generates and automatically inspects 3D underground structure data. A quality inspection program was developed. Through this study, it is judged that it will be meaningful as a basic research for improving the quality of underground structures on the integrated map of underground space by automating more than 98% of the 3D model inspection process, which is currently being conducted manually.

• Analytical Science and Technology
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• v.35 no.5
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• pp.205-211
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• 2022

Deuterium (D) is an isotope with one more neutron number than hydrogen (H). Heavy elements rarely change their chemical properties with little effect even if the number of neutrons increases, but low-mass elements change their vibration energy, diffusion rate, and reaction rate because the effect cannot be ignored, which is called an isotope effect. Recently, in the semiconductor and display industries, there is a trend to replace hydrogen gas (H₂) with deuterium gas (D₂) in order to improve process stability and product quality by using the isotope effect. In addition, as the demand for D₂ in industries increases, domestic gas producers are making efforts to produce and supply D₂ on their own. In the case of high purity D₂, most of them are produced by electrolysis of heavy water (D₂O), and among D₂, hydrogen deuteride (HD) molecules are present as isotope impurities. Therefore, in order to maximize the isotope effect of hydrogen in the electronic industry, HD, which is an isotope impurity of D₂ used in the process, should be small amount. To this end, purity analysis of D₂ for industrial processing is essential. In this study, HD quantitative analysis of D₂ for high purity D₂ purity analysis was established and hydrogen isotope RM (Reference material) was developed. Since hydrogen isotopes are difficult to analyze with general gas analysis instrument, they were analyzed using a high-precision mass spectrometer (Gas/MS, Finnigan MAT271). High purity HD gas was injected into Gas/MS, sensitivity was determined by a signal according to pressure, and HD concentrations in two bottles of D₂ were quantified using the corresponding sensitivity. The amount fraction of HD in each D₂ was (4518 ± 275) μmol/mol, (2282 ± 144) μmol/mol. D₂, which quantifies HD amount using the developed quantitative analysis method, will be manufactured with hydrogen isotope RM and distributed for quality management and maintenance of electronic industries and gas producers in the future.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.292-299
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• 2022

This study was conducted to analyze physical and chemical properties of horticultural substrates and response of hydroponically grown two cultivars of 'Namcheon' and 'Somirang' perilla by four different substrates: coir (chip:dust = 5:5), perlite, granular rockwool, and commercial mixed substrate (cocopeat:peatmoss:vermiculite:perlite: zeolite = 50:25:10:10:5). There were no significant differences in EC and pH according to substrates. Container capacity was the greatest in granular rockwool, and it showed appropriate levels in mixed substrate and coir. Air space was higher in coir and perlite than the other treatments. Bulky density reached a proper standard in all substrates excepting coir. The leaf length and width of 'Namcheon' indicated the most in mixed substrate, though the value of 'Somirang'was greatest in coir substrate. The leaf weight of both cultivars was highest in mixed substrate, and relatively low in coir and perlite. The total yield of leaves was separated by two groups: higher group, which are mixed substrate and granular rockwool, and lower group, which are coir and perlite. There was a large gap by 28% between these two groups. Therefore, this study suggests that substrates with high water holding capacity such as mixed substrate or granular rockwool are most suitable for the hydroponic cultivation of perilla, which require sufficient moisture supply to the root zone.

• Animal Bioscience
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• v.35 no.12
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• pp.1892-1903
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• 2022

Objective: A series of experiment were conducted to evaluate the effects of replacing a part of soybean meal (SBM) at 6% of broiler diets with fermented soybean meal (FSBM) obtained by single or two-stage fermentation by measuring growth performance, antioxidant activity in the jejunum and distal intestinal microflora. Methods: Soybean meal samples were prepared by single-stage fermentation using Bacillus velezensis (Bv) (FSBM_B), or Lactobacillus spp. (as commercial control) (FSBM_L). Additional SBM sample was prepared by two-stage fermentation using Bv and subsequently using Lactobacillus brevis ATCC 367 (Lb) (FSBM_B+L). Enzyme activity, chemical composition, trichloroethanoic acid-nitrogen solubility index (TCA-NSI) and antioxidant activity were measured. Then, in an in vivo study, 320 Ross308 broilers were divided into four groups with ad libitum supply of feed and water. Four groups were fed either a corn-soybean meal diet (SBM), or one of fermented SBM diets (FSBM_B+L, FSBM_B, and FSBM_L). Growth, serum characteristics, microflora, and the mRNA expression of selected genes were measured. Results: Compared to SBM, FSBM_B+L contained lower galacto-oligosaccharide, allergic protein, and trypsin inhibitor, and higher TCA-NSI by about three times (p<0.05). Reducing power and 1,1-diphenyl-2-picrylhydrazyl free radical scavenging ability correlated positively with the TCA-NSI content in FSBM. Growth performances were not significantly different among four groups. In jejunum of 35-day-old broilers, partial replacement of SBM by FSBM_B+L increased the activity of superoxide dismutase and catalase (CAT), and the FSBM_B group had the highest catalase activity (p<0.05). Partial replacement of SBM by FSBM increased relative mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and peptide transporter 1 (PepT1) (p<0.05); however, FSBM_B+L increased CAT mRNA level to 5 times of the control (p<0.05). Conclusion: Using Bv- and Lb-processed SBM through two-stage fermentation to partially replace 6% of diets will improve the gut's antioxidant activity under commercial breeding in broilers.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.497-505
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• 2021

Due to recent underground space accidents, are a frequent occurence in Korea, the government established the basic plan for the construction of the IUGIM (Integrated Underground Geospatial Information Map) in 2015 as a measure for safety management of underground spaces. The development of IUGIM was partially completed as of 2021. The underground space management entity and related organizations are utilizing it. This study is being carried out as part of a plan to improve the usability of IUGIM, and to build a visualization system that compares real-time field data with stored data. A system, equipped with a visualization function for borehole data and 6 types of underground facilities built and managed on IUGIM; a tool capable of comparative analysis with real-time data measured in the field, is being built. The 6 types of underground facilities are water supply pipe, sewage pipe, power pipe, gas pipe, communication pipe, and heating pipe. The completed system was demonstrated at three locations in Seocho-gu, Gangnam-gu in Seoul. The field demonstration was carried out by accessing the mobile center and downloading IUGIM data, visualizing IUGIM data (surface creation, borehole information, underground facilities), and visualizing the GPR(Ground Penetrating Radar)-based data acquired at the field. As a result of the empirical results of IUGIM data and GPR-based field data, it was judged to be suitable. As a result of this study, it is judged that it can be helpful for safe construction at the excavation site.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.3
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• pp.280-285
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• 1991

The rice culture techniques of the ancient China which have played a key role directly and indirectly, in development of ancient farming and its techniques of Korea, were established before Christ in terms of dry-farming and the spirit of the farming-first principle. Especially techniques of rice culture were developed by cultivation methods for deep plowing, storage of water and preservation use of soil fertility. Therefore, the techniques of transplanting methods, seeding in rows, use of iron-made farming tools and dam construction for irrigation were advanced. And rice varieties were differentiated to avoid disasters or to supply of rice for various uses in many areas. Also, because north China was the origin of Chinese agriculture in which population density was low and flat land was wide that were the cradle of Chinese agriculture, ‘Hwayungsunubeob’(firing and drawning weed control method) and fallowing were quickened as intensive techniques of rice culture. In connection with the view of agricuture with 'the theory of the cosmic dual forces and the five primary substances' of Han Mooje and Chamwye scholars, the techniques of seeding and selection of crops were gradually developed. From ‘Jeminyosul’ of the 6th century to ‘Wangjongnongseo’ of the 14th century, the techniques of rice culture have been developed continuously and additively, but were not improved thereafter Won dynasty. From this point of time, the time of agriculture in the end of Koryo age and by ‘Nongsajiksul’ were initiated.

• Membrane Journal
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• v.33 no.4
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• pp.181-190
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• 2023

Wastewater purification is one of the most important techniques for controlling environmental pollution and fulfilling the demand for freshwater supply. Various technologies, such as different types of distillations and reverse osmosis processes, need higher energy input. Capacitive deionization (CDI) is an alternative method in which power consumption is deficient and works on the supercapacitor principle. Research is going on to improve the electrode materials to improve the efficiency of the process. A reverse electrodialysis (RED) is the most commonly used desalination technology and osmotic power generator. Among many studies conducted to enhance the efficiency of RED, MXene, as an ion exchange membrane (IEM) and 2D nanofluidic channels in IEM, is rising as a promising way to improve the physical and electrochemical properties of RED. It is used alone and other polymeric materials are mixed with MXene to enhance the performance of the membrane further. The maximum desalination performances of MXene with preconditioning, Ti₃C₂T_x, Nafion, and hetero-structures were respectively measured, proving the potential of MXene for a promising material in the desalination industry. In terms of osmotic power generating via RED, adopting MXene as asymmetric nanofluidic ion channels in IEM significantly improved the maximum osmotic output power density, most of them surpassing the commercialization benchmark, 5 Wm^-2. By connecting the number of unit cells, the output voltage reaches the point where it can directly power the electronic devices without any intermediate aid. The studies around MXene have significantly increased in recent years, yet there is more to be revealed about the application of MXene in the membrane and osmotic power-generating industry. This review discusses the electrodialysis process based on MXene composite membrane.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.5
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• pp.427-434
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• 2023

Oysters are an important organism, accounting for an average of 76% of shellfish aquaculture production. In this study, optimal habitat was searched for by calculating the Habitat Suitability Index (HSI) using water temperature, salinity, hydrodynamics, DO, SS and Chl.a in Jaran Bay. As a result, the inside of Jaran Bay was found to be a more suitable habitat than the outside with a wide entrance and rapid hydrodynamics. Oyster production and HSI showed a significant correlation (0.710, p<0.05). Hydrodynamics helps the growth of aquaculture organisms, such as food supply through seawater exchange in the bay, which showed a high correlation (0.709, p<0.05) with oyster production. It was found to have a greater effect on habitat suitability than Chl.a. The results of this study are expected to be helpful for the efficient conservation, use and management of coastal fisheries.