• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.173-178
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• 2022

A lateral flow immunoassay (LFIA) method using carbon nanodot@silica as a signaling material was developed for analyzing the concentration of retinol-binding protein 4 (RBP4), one of the lung cancer biomarkers. Instead of antibodies mainly used as bioreceptors in nitrocellulose membranes in LFIA for protein detection, aptamers that are more economical, easy to store for a long time, and have strong affinities toward specific target proteins were used. A 5' terminal of biotin-modified aptamer specific to RBP4 was first reacted with neutravidin followed by spraying the mixture on the membrane in order to immobilize the aptamer in a porous membrane by the strong binding affinity between biotin and neutravidin. Carbon nanodot@silica nanoparticles with blue fluorescent signal covalently conjugated to the RBP4 antibody, and RBP4 were injected in a lateral flow manner on to the surface bound aptamer to form a sandwich complex. Surfactant concentrations, ionic strength, and additional blocking reagents were added to the running buffer solution to optimize the fluorescent signal off from the sandwich complex which was correlated to the concentration of RBP4. A 10 mM Tris (pH 7.4) running buffer containing 150 mM NaCl and 0.05% Tween-20 with 0.6 M ethanolamine as a blocking agent showed the optimum assay condition for carbon nanodot@silica-based LFIA. The results indicate that an aptamer, more economical and easier to store for a long time can be used as an alternative immobilizing probe for antibody in a LFIA device which can be used as a point-of-care diagnosis kit for lung cancer diseases.

• Economic and Environmental Geology
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• v.55 no.5
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• pp.429-438
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• 2022

This study evaluated the effect of the degree of weathering on the particle size distribution and the amount of fine particles generated in the aggregate production process during the crushing of igneous rock. Rock samples were collected from three areas with differences in strength from the Schmith hammer measurement at the aggregate quarry in Geochang, Gyeongsangbuk-do. After crushing with a jaw crusher under the same conditions in laboratory, particle size analysis, mineral analysis, chemical analysis, and weathering index were calculated. The Schmidt hammer measurements were 56, 28, and <10, and the CIA and CIW values of weathering index were also different, so the rock samples were classified into hard rock, soft rock, and weathered rock according to the weathering degree. It shows a smaller particle size distribution toward weathered rocks under the microscope, and the proportion of altered clay minerals such as sericite increased. The composition of feldspar and quartz was high for hard rock, and the ratio of muscovite and kaolinite was low. As a result of the crushing of the jaw crusher, hard rock produced a lot of coarse crushed material (13.2mm), while soft rock and weathered rock produced fine crushed material (4.75mm). The former showed the characteristics of the beta distribution curve, and the latter showed the bimodal distribution curve. The production of fine rock particles (based on 0.71mm of sieve, wt. %) increased to 13%<21%<22% in hard rock, soft rock, and weathered rock, and the greater the degree of weathering, the more fine rock particles were generated. The fine particles are recovered by the operation of the sand unit in the wet aggregate production process. Therefore, in order to minimize the amount of sludge generated in the aggregate production process, it was judged that a study on the optimal operation of cyclones could be necessary.

• Journal of Christian Education in Korea
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• v.70
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• pp.37-74
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• 2022

COVID-19, which occurred in Wuhan, China, made it difficult for Korean churches to face to face worship, therefore metaverse emerged as an alternative to solving these problems. metaverse is forming various platforms through technology expressed in 3I(Immersion, Interactive, virtual Image). The purpose of this study is to analyze the application plan of Christian education by applying metaverse technologies to Christian education. In order to achieve the purpose of this study, first, the definition, type, platform, and technology of the metaverse are presented to examine the key of the metaverse, second, in order to analyze the church from the theological educational aspect, the essence of the church, the mission of the church, and the metaverse church are examined, third in order to apply the metaverse to Christian education, it is classified into worship through the metaverse, education through the metaverse, service through the metaverse, the christian relationship through the metaverse, and missions through the metaverse. The application plan of the metaverse for Christian education is that first, worship can be held through metaverse. Second, education can be performed through the metaverse. Third, the metaverse can be used to fulfill the mission of service. Fourth, through the metaverse, christian can fellowship through the metaverse. Fifth, the missionary mission can be carried out through the metaverse. In conclusion, metaverse is still in the development stage, but various programs should be developed to achieve the purpose of Christian education by utilizing various platforms developed so far and utilizing the advantages of the platform. In particular, the Korean church will be able to utilize various programs such as Sunday worship, Sunday school, youth retreat, QT, Bible school, and pilgrimage through the metaverse to make good use of the characteristics of the metaverse. In addition, metaverse is an extended reality(XR) that integrates VR, AR, and MR, and its strength is an engagement in creative Christian educational activities out of the original Christian education. In the future, metaverse technology can be applied to Christian education in various ways as the fourth industrial technology is developing.

• Korean Journal of Plant Resources
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• v.35 no.4
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• pp.435-444
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• 2022

Hibiscus hamabo Sieb. et Zucc. (yellow hibiscus) is a deciduous semi-shrub plant and mainly growing in Jeju Island. This is known the unique wild hibiscus genus and classified as an 2nd grade of endangered plant for Korean Red List. In previous studies, properties of germination, ecological, genetical and salt resistance have been reported. In this study, we investigated mass-proliferated adventitious root using bioreactor, antioxidant and whitening effects to conduct functional ingredients. Yellow hibiscus were collected from Gujwa, Jeju by prior permission and they were introduced by explant type and various medium composition after surface sterilization. As a result, seed response rates were evaluated at range of 51.17~51.83%, in terms of comprehensive efficiency of shoot and root formation. In the case of adventitious root propagation condition was confirmed in half strength Murashige and Skoog medium salts, 30 mg/L sucrose, and 2 mg/L indole-3-butyric acid for 8 weeks in 5,000 mL bioreactor. We also compared between relationship with biomass and secondary metabolites accumulation by total phenolics content, the flavonoid content, DPPH free radical scavenging activity and melanin content. The results indicated that adventitious root mass proliferation, antioxidant and whitening effect could develop value of the high-quality cosmeceutical ingredient and further metabolite studies.

• Elastomers and Composites
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• v.22 no.3
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• pp.204-212
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• 1987

The purpose of this study is to investigate the reinforced effect between MGF treated silane coupling agents and rubber matrix under the configuration chemical bonds, also the effect of triazine thiol compounds. For this study, vulcanizates were prepared with fifteen different compounding formulas. Their vulcanization characteristics, physical properties were examined by means of the ODR(Oscillating Dist Rheometer), the tensile tester, the benzene swelling test. The results of this study obtained are as follows: 1. In the ODR test, the MA vulcanizate was the fastest one in terms of having reached to optimum cure time($t_{90}$) and, with the same formula, when MGF vulcanizates, the shortest optimum cure times has appeared. 2. The SA, SC vulcanizates were the best the other in the physical properties such as 100%modulus, 200%modulus, 300%modulus, tensile strength. The SB vulcanizate, with higher density of crosslinking than other vulcanizates. The vulcanizates, which were filled with MGF treated with silane coupling agents we were the higher density of crosslinking than vulcanizates filled with MGF only. 3. In aging properties, the silica vulcanizates appeared to be better than the other vulcanizates. The aging Properties of treated MGF vulcanizates were similar to the silica vulcanizates. The(CR+APS+silica) and(CR+APS+MCF) were easily crosslinked by exposure to the air, and the physical properties have been improved.

• Journal of the Korean Electrochemical Society
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• v.26 no.1
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• pp.1-10
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• 2023

The cathode, which is one of the four major components of a lithium secondary battery, is an important component responsible for the energy density of the battery. The mixing process of active material, conductive material, and polymer binder is very essential in the commonly used wet manufacturing process of the cathode. However, in the case of mixing conditions of the cathode, since there is no systematic method, in most cases, differences in performance occur depending on the manufacturer. Therefore, LiMn₂O₄ (LMO) cathodes were prepared using a commonly used THINKY mixer and homogenizer to optimize the mixing method in the cathode slurry preparation step, and their characteristics were compared. Each mixing condition was performed at 2000 RPM and 7 min, and to determine only the difference in the mixing method during the manufacture of the cathode other experiment conditions (mixing time, material input order, etc.) were kept constant. Among the manufactured THINKY mixer LMO (TLMO) and homogenizer LMO (HLMO), HLMO has more uniform particle dispersion than TLMO, and thus shows higher adhesive strength. Also, the result of the electrochemical evaluation reveals that HLMO cathode showed improved performance with a more stable life cycle compared to TLMO. The initial discharge capacity retention rate of HLMO at 69 cycles was 88%, which is about 4.4 times higher than that of TLMO, and in the case of rate capability, HLMO exhibited a better capacity retention even at high C-rates of 10, 15, and 20 C and the capacity recovery at 1 C was higher than that of TLMO. It's postulated that the use of a homogenizer improves the characteristics of the slurry containing the active material, the conductive material, and the polymer binder creating an electrically conductive network formed by uniformly dispersing the conductive material suppressing its strong electrostatic properties thus avoiding aggregation. As a result, surface contact between the active material and the conductive material increases, electrons move more smoothly, changes in lattice volume during charging and discharging are more reversible and contact resistance between the active material and the conductive material is suppressed.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.15-25
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• 2023

In this study, silicon sludge from semiconductor dicing process is recycled to fabricate silica nanoparticles, which are applied as dispersing materials for electro-responsive (ER) smart fluid. In specific, metal impurities are removed from silicon sludge by acid washing to obtain the high-purity silicon powder. And then, silica nanoparticles are synthesized by facile hydrothermal method employing the silicon powder as reactant material. To control the size of silica nanoparticles, the reaction time of hydrothermal method is varied as 8, 15, 20, and 30 hours are applied to control the size of silica nanoparticles. Sizes of silica nanoparticles are increased proportionally to the reaction time owing to the increased numbers of hydrolysis and condensation reactions. As-synthesized silica nanoparticles are prepared as electro-responsive smart fluids by dispersing into silicon oil. Silica nanoparticles synthesized by 30 hours of hydrothermal reaction (SiO₂-H30) exhibit the highest shear stress of 21.4 Pa under an applied electric field strength of 3.0kV mm^-1. Such enhancement in ER performance of SiO₂-H30 among various silica nanoparticles are attribute to the reinforcing effect originated from the mixed particle size, which allowing the formation of rigid chain-like structures. Accordingly, this study successfully propose a recycling method of silicon sludge to synthesize silica nanoparticles and their derived ER fluids, which may suggest new possibility to ESG management emphasizing the eco-friendliness.

• Korean Journal of Social Welfare Studies
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• v.41 no.1
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• pp.251-279
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• 2010

In 2009 the Ministry of Health and Society reported a new milestone in longevity among people living with HIV and AIDS (PLWHA): An individual was reported to be living and healthy after 24 years with HIV/AIDS. Today, PLWHA who receive treatment are more likely to die as a result of cancer or cardiovascular diseases than HIV/AIDS. However, in Korea the public association between HIV/AIDS and death remains strong and PLWHA live with the feeling of being discarded. While great advances have been made in the treatment of HIV/AIDS, understanding of life with HIV/AIDS is just beginning. This study describes the life experiences of PLWHA after being diagnosed with HIV/AIDS. Phenomenological methods were used to analyze the transcripts of semi-structured interviews with six PLWHA. Time is a constant factor in the life experiences of PLWHA. After being diagnosed, participants were shocked, feeling as though the world was caving in and they were living with a time bomb. Compulsory disclosure left PLWHA with a feeling of disconnection from the world. Participants were fired from their jobs, resulting in poverty, isolation and a sense that they were simply waiting to die. However, health professionals informed participants that HIV/AIDS is a manageable illness. With time, PLWHA came to understand HIV/AIDS differently. In accepting their HIV infection, PLWHA created a new sense of meaning in their lives. To be honest to their loved ones and true to their own identity, PLWHA worked to "come out." The experience of coming out helped them to accept themselves as they were and understand their own strength. The most important influence on their treatment, and living with HIV/AIDS generally, was obtaining correct information about HIV/AIDS from health professionals. After accepting that they were living with HIV/AIDS, participants were able to look beyond themselves to support those around them, including family members, friends, and others who encouraged them to recognize and feel confident in their own identity.

• Journal of the Korean Geotechnical Society
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• v.24 no.4
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• pp.101-114
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• 2008

Pressurized grouting is a common technique in geotechnical engineering applications to increase the stiffness and strength of the ground mass and to fill boreholes or void space in a tunnel lining and so on. Recently, the pressurized grouting has been applied to a soil-nailing system which is widely used to improve slope stability. Because interaction between pressurized grouting paste and adjacent ground mass is complicated and difficult to analyze, the soil-nailing design has been empirically performed in most geotechnical applications. The purpose of this study is to analyze the ground behavior induced by pressurized grouting paste with the aid of laboratory model tests. The laboratory tests are carried out for four kinds of granitic residual soils. When injecting pressure is applied to grout, the pressure measured in the adjacent ground initially increases for a while, which behaves in the way of the membrane model. With the lapse of time, the pressure in the adjacent ground decreases down to a value of residual stress because a portion of water in the grouting paste seeps into the adjacent ground. The seepage can be indicated by the fact that the ratio of water/cement in the grouting paste has decreased from a initial value of 50% to around 30% during the test. The reduction of the W/C ratio should cause to harden the grouting paste and increase the stiffness of it, which restricts the rebound of out-moved ground into the original position, and thus increase the in-situ stress by approximately 20% of the injecting pressures. The measured radial deformation of the ground under pressure is in good agreement with the expansion of a cylindrical cavity estimated by the cavity expansion theory. In-situ test revealed that the pullout resistance of a soil nailing with pressurized grouting is about 36% larger than that with regular grouting, caused by grout radius increase, residual stress effect, and/or roughness increase.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.413-422
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• 2022

Barnea manilensis is a bivalve which bores soft rocks, such as, limestone or mudstone in the low intertidal zone. They make burrows which have narrow entrances and wide interiors and live in these burrows for a lifetime. In this study, the morphology and the microstructure of the valve of rock-boring clam B. manilensis were observed using a stereoscopic microscope and FE-SEM, respectively. The chemical composition of specific part of the valve was assessed by energy dispersive X-ray spectroscopy (EDS) analysis. 3D modeling and structural dynamic analysis were used to simulate the boring behavior of B. manilensis. Microscopy results showed that the valve was asymmetric with plow-like spikes which were located on the anterior surface of the valve and were distributed in a specific direction. The anterior parts of the valve were thicker than the posterior parts. EDS results indicated that the valve mainly consisted of calcium carbonate, while metal elements, such as, Al, Si, Mn, Fe, and Mg were detected on the outer surface of the anterior spikes. It was assumed that the metal elements increased the strength of the valve, thus helping the B. manilensis to bore sediment. The simulation showed that spikes located on the anterior part of the valve received a load at all angles. It was suggested that the anterior part of the shell received the load while drilling rocks. The boring mechanism using the amorphous valve of B. manilensis is expected to be used as basic data to devise an efficient drilling mechanism.