• Journal of Mushroom
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• v.20 no.4
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• pp.274-278
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• 2022

The present study aimed at selecting a cost-effective substrate for king oyster mushroom based on the growth characteristics of fruiting body for use as a basic resource to ensure stable production on farms. Compositional analysis of substrates manufactured with different materials in each process revealed that the total carbon content was 42.24-48.22% higher and the total nitrogen content was 1.7-2.29% higher in the processed lot than in the control (i.e., substrate used by the farmhouse; 40.86% and 1.39%, respectively). Meanwhile, the carbon-to-nitrogen ratio was the highest in the control (27.9% vs. 19.12-27.88% in the processed lot). When cultured for 28 days, the mycelium growth was 11.5 and 11.3 mm in substrates 1 and 6, respectively, indicating the fastest growth; meanwhile, the values were 10.1-10.3 mm in the control and substrate 11, showing a similar tendency. Mycelial density did not differ significantly among the processed lots. Yield per bottle was higher in substrates 8 (205.95 g/bottle), 7 (178.51 g/bottle), and 11 (170.63 g/bottle) than in the control (152.2 g/bottle). Fruiting body quality was comparable to controls in all processed lots. Overall, economic effects, such as substrate material prices, should be analyzed, and stability evaluations, such as residual pesticide and harmful microorganisms, should be undertaken along with further detailed examination to ensure safe and stable production on farms.

• Science of Emotion and Sensibility
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• v.24 no.4
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• pp.149-156
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• 2021

The mechanical properties of a woven fabric made of SiC (silicon carbide) fibers were determined in this study using the KES-FB system. The woven fabric is used in high heat settings above 1500℃. Composite spun yarns were used to create SiC fibers. By analyzing the wearing properties, we studied the prospect of using the textiles as fire-retardant work clothes. Mechanical properties determine the wearing attributes. Therefore, the tensile linearity (LT), tensile resilience (RT), and shear stiffness (G) values of the fabric varied according to the yarn type (filament or spun yarn). The thickness, weight per square meter, and density of the fabric were found to have an effect on the shear hysteresis (2HG) and compression resilience (RC) values. In terms of wearable clothing qualities, the fabric qualities of the SiC composite yarn demonstrated the highest ratio of compressive energy to thickness (WC/T), which indicates bulkiness. The fabric manufactured from SiC composite yarns passed the KFI criteria for carbonation length and cumulative flame time in the flame-retardant test. Therefore, we discovered that the material can be used as a fire-resistant work cloth.

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.373-380
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• 2022

In this study, Chung's equations 1, 2, and 3 were extended to standardize smoke safety rating evaluation in case of fire, and Chung's equations-V, smoke performance index-V, and smoke growth index-V were calculated. Five types of wood were selected and their smoke indices were measured using the cone calorimeter method according to ISO 5660-1. The smoke risk was graded by the smoke risk index-VI according to Chung's equation-VI. Smoke risk index-VI increased in the order of PMMA (1) ≈ maple (1.01) < ash (1.57) < needle fir (4.98) < paulownia (46.15) < western red cedar (106.26). It was predicted that maple and ash had the lowest smoke risk, and paulownia and western red cedar had the highest. The five samples' CO mean production rate (COP_mean) was 0.0009~0.0024 g/s, indicating that these woods were incompletely burned than the polymethyl methacrylate (PMMA) reference material. Regarding the smoke properties of the chosen woods, the smoke performance index-V (SPI-V) increased as the bulk density increased, and the smoke risk index-VI (SRI-VI) decreased.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.683-691
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• 2021

The purpose of this study is to measure the yield and to evaluate the physiological activity of Cannabis sativa seed(Hemp seed) extracts extracted using a density fluctuation supercritical carbon dioxide for each temperature condition-30℃(HSSE30), 45℃(HSSE45), 60℃(HSSE60), and to enable dissolution of the poorly water-soluble extracts by liposome formulation and to enhance the skin permeability. As a result of the yield measurement, HSSE60 showed the highest yield, and in the antioxidant activities, HSSE45 had the highest total polyphenol content, and showed the highest DPPH, ABTS+ radical scavenging activities at the highest concentration of the extracts. As a result of the antimicrobial susceptibility testing, a clear zone appeared only in the Propionibateium acnes strain. It was confirmed that particle size was reduced and the absolute value of the zeta potential increased in the case of the formulation in which the extracts were in liposomes than in the formulation in which the extracts were dissolved in deionized water, and the skin permeability was improved. Based on these experimental results, we confirmed the possibility of using the hemp seed supercritical carbon dioxide extracts, a poorly water-soluble extract, can be applied as a functional natural material for cosmetics.

• Journal of radiological science and technology
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• v.45 no.6
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• pp.523-529
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• 2022

Gamma spectroscopy analysis is widely used for radioactivity analysis, and various factors are required for radioactivity calculations. Among the factors, K3 for each sample significantly influences the results. The previous methods of correcting the self-absorption effect include a computational simulation method and a method that requires making a CRM(certified reference material) identical to the sample medium. However, the above methods have limitations when used in small institutions because they require specialized program utilization skills or high manufacturing costs and large facilities. The aim of this study is to develop a method that can be easily and rapidly applied to radioactivity analysis. After filling the beaker with water, we placed the radiation source in a uniform position and used the measured value as the benchmark. Next, a correction factor was derived based on the difference in the radiation source count of the benchmark and the identically measured sample. For the radiation source, Eu-152, which emits a broad range of energy within the measurement range of gamma rays, and Cs-134 and Cs-137, which are indicator nuclides in environmental radiation analysis, were used. The sample was selected within the density range of 0.26-2.11 g/cm³, and the correction factor was derived by calculating the count difference of each sample compared to the reference value of water. This study presents a faster and more convenient method than the existing research methods for determining the self-absorption effect correction, which has become increasingly necessary.

• 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 Radiology
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• v.17 no.4
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• pp.497-506
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• 2023

In the case of radiation workers in medical institutions, radiation exposure is made for patient protection and accurate procedures, so they have a problem of low dose exposure. Low-dose radiation exposure occurs mainly in parts of the body other than the Apron area, and the most frequent place is the skin of the back of the hand. In particular, since the medical personnel's hands require senses and fine movements during the procedure, they are defenseless in the radiation exposure area and are at risk of exposure. It can solve the problem of shielding such as lead gloves, and it is difficult to use by suggesting the activity of the hand during the procedure. To solve this problem, a shielding cream capable of obtaining a functional radiation protection effect was developed and its shielding performance was compared with lead equivalent of 0.1 mmPb. In the process of manufacturing shielding cream, the shielding performance was improved by adding a defoaming process to reduce air holes to increase the density of the cream. Therefore, the shielding cream using barium sulfate as the main material has a lower shielding rate than the lead plate, and in the realm of effective energy, it is 59%, At high effective energy, a difference of about 37% was shown, indicating that there is a functional radiation protection effect. The advantage is that it can be used directly on the skin, and it is considered that it can be used before wearing surgical gloves and has a permanent protective effect.

• Journal of the Korean Geotechnical Society
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• v.25 no.12
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• pp.57-67
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• 2009

Along with the advanced construction technologies, the maximum size of coarse aggregate used for dam construction ranges from several cm to 1m. Testing the original gradation samples is not only expensive but also causes many technical difficulties. Generally, indoor tests are performed on the samples with the parallel grading method after which the results are applied to the design and interpretation of the actual geotechnical structure. In order to anticipate the exact behavior characteristics for the geotechnical structure, it is necessary to understand the changes in the shear behavior. In this study, the Large Triaxial Test was performed on the parallel grading method samples that were restructured with river bed sand-gravel, with a different maximum size, which is the material that was used to construct Dam B in Korea. And the Stress - Strain characteristics of the parallel grading method samples and the characteristics of the shear strength were compared and analyzed. In the test results, the coarse-grained showed strain softening and expansion behavior of the volume, which became more obvious as the maximum size increased. The internal angle of friction and the shear strength appeared to increase as the maximum size of the parallel grading method sample increased.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.255-264
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• 2022

The conventional spot-type UV curing machine configures a collimator optical system using a plurality of lenses so that the light beam is incident through an optical cable. In order to increase the transmission light efficiency, a collimator optical system composed of three or more lenses is required, and accordingly, it is difficult to align the optical system, and it is difficult to implement the system compactly. In this study, a single TIR lens collimator that can realize the same level of spot diameter and light efficiency as the conventional collimator optical system composed of three lenses was designed. Through this, the light efficiency at the curing area with the minimum illuminance deviation was 33.2 %, which was similar to the performance of the reference collimator optical system, and the illuminance deviation on the curing area was 18.8 %, ensuring acceptable performance. In addition, by arranging a fly-eye lens with field flattening function at the front end of the condensing lens, the effective curing area diameter was reduced from 5.0 mm to 3.0 mm, enabling higher curing energy density to be realized. In addition, it was confirmed that the illuminance deviation can be greatly improved to a level of 14.4%.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.94-101
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• 2023

Zinc oxide(ZnO) is a semiconductor material with a bandgap of 3.37 eV and an exciton binding energy of 60 meV for various applications. Recently ZnO has been proven to enhance its electrical properties for utilization as an alternative for transparent conducting oxide (TCO) materials. In this study, cation(Al, Ga)-anion(F) single and double doped ZnO thin films were grown by atomic layer deposition (ALD) to enhance the electrical properties. The structural and optical properties of doped ZnO thin films were analyzed, and doping effects were confirmed to electrical characteristics. In single doped ZnO, it was observed that the carrier concentration was increased after doping, acting as a donor to ZnO. Among the single doping elements, F doped ZnO(FZO) showed the highest mobility and conductivity due to the passivation effect of oxygen vacancies. In the case of double doping, higher electrical characteristics were observed compared to single doping. Among the samples, Al-F doped ZnO(AFZO) exhibited the lowest resistance value. This results can be attributed to an increase in delocalized electron states and a decrease in lattice distortion resulting from the differences in ionic radius. The partial density of states(PDOS) was also analyzed and observed to be consistent with the experimental results.