• Journal of Bio-Environment Control
• /
• v.30 no.4
• /
• pp.304-311
• /
• 2021

This Experiment was conducted to determine the effects of light shield materials when melon grown inside a plastic greenhouse in summer season. The average temperatures were 36.6℃, 34.5℃ and 34.0℃ respectively for the control(non-shield), coating agent, and the white net. The light transmittances were 69% and 75%, respectively inside the greenhouse treated with the coating agent and white net immediately after applicants, compared with that inside the control greenhouse. At the 40 and 80 days after treatment, the light transmittances for the coating agent were 92% and 98%, respectively, indicating it was slowly decomposed and removed, but there was no change in the transmittance for the white net. While the leaf number did not differ among the treatments, the plant height was higher in the white net and shading agent than in control. The weight of the leaves, fresh-weight and dry-weight were no different from that of shading, but it became heavier in the later stages. The marketable fruit yield was increased by 6% for white nets and 5% for the coating agent compared to control, there was no statistical significance. Therefore, coating agent is considered as an effective method to lower temperature during high temperature period, but it is preferable to use it in consideration of cultivation period, because the coating agent is gradually removed.

• Journal of Mushroom
• /
• v.19 no.3
• /
• pp.140-149
• /
• 2021

Mushroom-derived polysaccharides, which are the primary bioactive constituents, are beneficial for human health. Polysaccharides have immuno-modulation, antitumor, and antioxidant properties. Additionally, they have antiviral properties and protect against chronic radiation stress. In this study, high yield water-soluble polysaccharides were obtained from Pleurotus djamor var. roseus basidiocarps. The crude polysaccharide (CP) was extracted sequentially by hot water and ethanol precipitation. The yield of the brown CPs was 5.6% dw. Diethylaminoethyl cellulose and Sepharose-6B column chromatography of CPs generated several fractions. Total glucan content was determined in all the fractions. The F1 fraction displayed the highest sugar content and was considered as a purified polysaccharide (PP). The total glucan and β-glucan content in the four fractions ranged between 76.85-2.95% and 75.08-1.46%, respectively. The yield of the PPs was 300 mg, and it was obtained as a white powder. The PPs were characterized by Fourier-transform infrared spectroscopy (FTIR) and thin-layer chromatography. The FTIR spectral details confirmed the presence of a xylopentose polysaccharide. The antioxidant activity of the PPs was evaluated using in vitro 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay and superoxide radical scavenging assay. The PPs showed strong DPPH free radical and superoxide anion radical scavenging activities in a dose-dependent manner. Purified PPs free of phenolics, protein, and carbohydrates were mainly responsible for the radical scavenging activity. The data suggest the potential of PPs as natural antioxidants.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.34 no.2
• /
• pp.113-120
• /
• 2021

The wave-propagation phenomenon in an infinite medium has been used to describe the physics in many fields of engineering and natural science. Analytical or numerical methods have been developed to obtain solutions to problems related to the wave-propagation phenomenon. Energy radiation into infinite regions must be accurately considered for accurate solutions to these problems; hence, various numerical and mechanical models as well as boundary conditions have been developed. This paper proposes a new boundary condition that can be applied to scalar-wave or horizontally-polarized shear-wave (or SH-wave) propagation problems in layered waveguides. A governing equation is obtained for the SH waves by applying finite-element discretization in the vertical direction of the waveguide and subsequently modified to derive the boundary condition for the infinite region of the waveguide. Using the orthogonality of the eigenmodes for the SH waves in a layered waveguide, the new boundary condition is shown to be equivalent to the existing root-finding absorbing boundary condition; further, the accuracy is shown to increase with the degree of the new boundary condition, and its stability can be proven. The accuracy and stability are then demonstrated by applying the proposed boundary condition to wave-propagation problems in layered waveguides.

• Journal of Internet Computing and Services
• /
• v.23 no.2
• /
• pp.29-35
• /
• 2022

UV rays have beneficial or harmful effects on the human body depending on the degree of exposure. An accurate UV information is required for proper exposure to UV rays per individual. The UV rays' information is provided by the Korea Meteorological Administration as one component of daily weather information in Korea. However, it does not provide an accurate UVI at the user's location based on the region's Ultraviolet index. Some operate measuring instrument to obtain an accurate UVI, but it would be costly and inconvenient. Studies which assumed the UVI through environmental factors such as solar radiation and amount of cloud have been introduced, but those studies also could not provide service to individual. Therefore, this paper proposes a deep learning model to calculate UVI using solar object information and sunlight characteristics to provide an accurate UVI at individual location. After selecting the factors, which were considered as highly correlated with UVI such as location and size and illuminance of sun and which were obtained through the analysis of sky images and solar characteristics data, a data set for DNN model was constructed. A DNN model that calculates the UVI was finally realized by entering the solar object information and sunlight characteristics extracted through Mask R-CNN. In consideration of the domestic UVI recommendation standards, it was possible to accurately calculate UVI within the range of MAE 0.26 compared to the standard equipment in the performance evaluation for days with UVI above and below 8.

• Journal of Sensor Science and Technology
• /
• v.31 no.3
• /
• pp.180-186
• /
• 2022

Photosynthetically active radiation flux density (PPFD) and daily light integral (DLI) values related to plant photosynthesis were obtained using the sunlight time and insolation data points in the agricultural weather sensor data for Jinan-gun, Jeollabuk-do, Korea from 2016 to 2020. The objective was to optimize the photo-environmental conditions for cultivating ginseng. The range of average monthly sunshine duration was 395.5-664.1 min, with the longest duration observed in June. The range of average annual accumulated daily insolation was 11.98-17.65 MJ·m^-2. The range of average daily external DLI calculated from the insolation and solar time data was 22.3-36.1 mol·m^-2·d^-1, and the annual cumulative DLI was 8,156-13,175 mol·m^-2·d^-1. Both the insolation and DLI values were the highest in 2016 and lowest in 2020. Based on the PPFD required for ginseng growth (111-185 µmol·m^-2·s^-1), the monthly average daily DLI and monthly cumulative DLI were 3.51-5.87 and 82-228 mol·m^-2·d^-1, respectively. The range of five-year average value for the external monthly cumulative DLI was 298-1,459 mol·m^-2·d^-1, and the monthly cumulative DLI values when a black double shading film and blue-white shading film were applied were 101-496 and 36-175 mol·m^-2·d^-1, respectively. A comparative analysis of DLI values indicated that shading was required to ginseng growth throughout the year under natural light. When the black double shading film was used, shading was required from March to October. When the blue-white shading film was applied from April to August, (i.e., the period with active ginseng growth) the appropriate DLI for ginseng growth could be continuously maintained. Regional weather differences due to climate change are gradually increasing, and even in one region, monthly and cumulative DLI values are different every year. Therefore, in order to implement a precise agricultural environment for ginseng cultivation, precise analysis and continuous research using agricultural weather sensor big data is required.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.25 no.4
• /
• pp.311-325
• /
• 2023

This study was conducted to analyze the habitat suitability of the major honey trees including Kalopanax septemlobus Koidz., Prunus spp., Tilia spp., and Styrax obassia Siebold & Zucc. indigenous to mountain Gariwang and Yumeong using the machine learning approach (i.e., MaxEnt model). The AUC values of the model predictions were mostly above 0.7, and the results of the response curves showed that the environmental drivers that had effects on the habitat suitability of the major honey trees were elevation, mean annual precipitation, and mean annual temperature. These results indicate that climatic drivers along the elevation gradient are the main environmental drivers in explaining the distribution patterns of the major honey trees. In addition, the results of the response curves of Prunus spp. and Styrax obassia Siebold & Zucc. differed slightly in terms of slope and mean annual solar radiation as the main environmental drivers. The results of this study will be valuable for the establishment of honey tree forests and management plans for the natural and artificial forests in South Korea, as well as for the mapping the distribution of honey trees. Further studies at different regional levels, reflecting biotic drivers, will be needed to expand the production of honey and pollen at different strata and to produce honey annually.

• Korean Journal of Mineralogy and Petrology
• /
• v.36 no.4
• /
• pp.259-271
• /
• 2023

Since the short-wave infrared spectrum has a significant range of variation depending on the production environment, countries with advanced resource exploration are collecting the spectrum and building a database. Representative organizations include the USGS and CSIRO, and they are currently carrying out a project in China that can synthesize and use a large number of existing data. The USGS library provides a total of 2,457 spectra targeting not only minerals but also various materials that respond to infrared radiation. Among these, there are 1,276 mineral spectra, which are about half of the total. The spectrum title includes information, such as analysis devices (NIC4, BECK, ASDNG, etc.), purity codes (a, b, c, d, u), and measurement methods (AREF, RREF, RTGC, TRAN). Analyzed raw data are provided in ASCII and GIF format. The CSIRO library has a total of 502 spectra, of which the majority, 493, correspond to mineral spectra. The USGS library is a free, publically available resource, while the CSIRO library is bundled with TSG8 or must be purchased separately. Among these, when comparing the eight spectra whose spectral shapes can be analyzed with the spectra of domestic illite, the positions of the absorption peaks are significantly different from those of domestic illite, except for one Japanese illite. Additional research will be needed to determine the causes of such differences, and the domestically relevant databases should be established as well.

• Food Science and Preservation
• /
• v.30 no.1
• /
• pp.170-178
• /
• 2023

We investigated the free radical scavenging and digestive enzyme inhibitory activities of the hot water extract of peach twig (Prunus persica L. Bastch). This extract of the peach twigs was further split up into n-hexane, ethyl acetate (EtOAc), and n-butyl alcohol(n-BuOH), which resulted in three solvent-soluble fractions. Free radical scavenging activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺) assay systems, while hypoglycemic effect of the peach twig extract and the solvent-soluble fractions were tested using α-glucosidase and α-amylase inhibition assays. Accordingly, the EtOAc layer showed a greater free radical scavenging activity compared to other solvent-soluble fractions. Furthermore, based on the α-glucosidase and α-amylase assays, the IC₅₀ values were determined to be 38.2±1.6 and 69.6±6.1 ㎍/mL for the EtOAc-soluble fractions, respectively. Taken together, these results suggest that the fractions obtained from the peach twig extract can be considered as a potential source of natural antioxidant and hypoglycaemic constituents.

• Journal of the Korean Wood Science and Technology
• /
• v.38 no.4
• /
• pp.333-340
• /
• 2010

The Korean Dendropanax lacquer, made from a natural resinous sap from Dendropanax orbifera Lev., was used as a golden and transparent varnish for the traditional artifacts (armor uits, helmets, arrowheads, etc.) to make them be brilliant golden color. The cured film of the acquer has excellent protective properties such as weatherability, water resistance, and nticorrosive. But, one of disadvantages is that takes a long time and much energy to fulfill curing the lacquer. The chemical constituents of the lacquer contained conjugated diene compounds s the photopolymerizable monomers. These monomers easily polymerized in sunlight to form olden-colored, hard-coating films in a short time. Photooxidation may be one of the most mportant reactions in the chemistry of the lacquer. Although the Korean Dendropanax Lacquer hould be dried to a thoroughly dry stage to achieve optimal film properties, curing with elevated emperatures may be required for the protracted curing time at atmospheric temperature. So we ntended to accelerate the curing rate of the lacquer by dual curing of thermal and radiation uring. The effect of thermal initiator on the thermal curing reaction was evaluated by monitoring he changes in double bond peak with FT-IR. Then the curing rate of the lacquer blended with hermal initiator and photoinitiator together was measured during dual curing using a RPT with V spot curing machine. Thermal initiator not only accelerated the curing rate but also improved he physical property. And the curing rate of the Korean Dendropanax lacquer was improved by ual curing method of thermal and UV curing. According to these results, the application area of he Korean Dendropanax lacquer could be expanded to surface coatings for electronic devices uch as mobile phones or electronics.

• Applied Chemistry for Engineering
• /
• v.29 no.1
• /
• pp.81-96
• /
• 2018

In this study, physicochemical properties of the natural jadeite powder were investigated and also the wash-off pack and liquid foundation containing the jadeite powder were prepared. In addition, each of these formulations was evaluated by various functional effects, sensory evaluation, stability and skin safety. In the wash-off pack, the far-infrared ray emissivity and radiation energy values increased as a function of the jadeite powder content. At a 3% jadeite powder content, the skin temperature increased by about $0.5^{\circ}C$ when the jadeite powder-containing formulation was applied to the skin. Besides, the chroma of the liquid foundation containing the jadeite powder more clearly expressed the original color of the skin. Moisture content measurements of the wash-off pack and liquid foundation containing the jadeite powder showed the highest moisture uptake of 5.0% and 63.0%, respectively. In sensorial test, the wash-off pack formulations containing the jadeite powder demonstrated improved affinities toward a skin, adherency, and moistness and combatted itching. The liquid foundation containing jadeite powder showed also improved affinities except for the coverage when compared to control formulations. Furthermore, the stability evaluation for 8 weeks revealed neither discoloration nor separation phenomenon for the formulations containing the jadeite powder. Moreover, the pH was found to be stable up to 8 weeks and the viscosity up to 4 weeks. Skin safety assessments showed that all formulations containing the jadeite powder were non-irritating. These results suggest that the jadeite powder as an inorganic pigment may serve as a new multi-functional cosmetic ingredient with stability and safety.