이산화탄소 배출이 없는 고분자 전해질 막 연료전지(polymer electrolyte membrane fuel cell, PEMFC)는 수송용, 발전용 시스템에 적용 가능한 친환경 에너지 변환장치이다. PEMFC의 주요 구성품 중 하나인 고분자 전해질 막(polymer electrolyte membrane, PEM)은 구동시간 동안의 높은 수소 이온 전도도와 물리화학적 안정성 갖춘 과불소화계 고분자 (perfluorinated sulfonic acid, PFSA) 기반 PEM (PFSA-PEM)이 상용화 되어있다. 하지만 PFSA-PEM의 단점으로 지적되는 낮은 유리전이온도와 높은 기체 투과도의 보완이 요구되고 있다. 이에 본 총설에서는 PFSA-PEM의 성능 향상 및 단점 보완 을 위해 1) PFSA의 측쇄부 길이를 조절함으로써 이온교환용량의 증가와 고분자의 결정성을 증가시켜 PFSA-PEM의 능력을 향상시킨 연구와 2) 유/무기 첨가제를 도입하여 수소 이온 전도도 및 물리적 안정성을 향상시키는 복합 막 연구 및 3) 다공성 지지체를 도입하여 PEM의 두께를 효과적으로 감소시켜 막 저항을 효과적으로 줄이고 내구성을 큰 폭으로 개선한 다공-충진 막에 관한 연구를 소개하고자 한다.

Molten salt reactor (MSR) is one of the non-pressurized-water fourth-generation reactors that uses liquid nuclear fuel that integrates coolant and nuclear fuel, so it is a safe reactor that can fundamentally prevent severe accidents caused by coolant loss. MSR uses NaCl-MgCl2 as a coolant salt, which is considered a promising diluent that can dissolve the fuel salt by forming an eutectic mixture. In this study, a zone-melting system was used to remove impurities from the NaCl-MgCl2 used in MSR. The system was designed in detail to control eutectic salt impurities by traversing long charges into a small molten zone.

We developed a 100 kW Class Transferred Type Plasma Torch applicable for melting of noncombustible metal wastes. By employing reverse polarity discharge structures for hollow electrode plasma torch, a transferred type arc plasma was generated stably with long arc length higher than 10 cm at the arc currents of ~400 A and gas (N2) flow rate of ~50 lpm. High arc currents and high arc voltages caused by the increased arc length could input high power level of ~100 kW to the noncombustible metal wastes, enabling quick melting. In addition, relatively long arc length and low gas flow rates can help reduce the deposition of melted materials on the exit surface of the torch. Thanks to these features, the developed plasma torch is expected to be suitable for small-scaled and portable melting system.

The reliable information on the hydraulic characteristics of rock mass is one of the key site factors for design and construction of deep subsurface structures such as geological radioactive nuclear waste disposal repository, underground energy storage facility, underground research laboratory, etc. In order to avoid relying on foreign field test technology in future projects, we have independently designed and made integrated type main frame, 120 bar waterproof downhole sonde, and 1,200 m wireline cable winch through a series of R&D activities. They are core apparatuses of the Deep borehole Hydraulic Test System (DHTS). Integration of individual test equipment into a single main frame allows safe and efficient work in the harsh field condition. The DHTS was developed aiming primarily for constant pressure (head) injection test and pulse test in deep impermeable rock mass. The maximum testing depth of the DHTS is about 1,050 m from the surface. Using this system, it is possible to make precise stepwise control of downhole net injection pressure in less than 2.0 kgf/cm2 with dual hydraulic volume controller and also to inject and measure the very low flow rate below 0.01 l/min with micro flow rate injection/control module. Over the past two years, we have successfully completed more than 50 in situ hydraulic tests at 5 deep boreholes located in the Mesozoic granite and sedimentary rock regions in Korea. Among them, the deepest testing depth was more than 920 m. In this paper, the major characteristics of the DHTS are introduced and also some results obtained from the high precision field tests in the deep and low permeable rock mass environment are briefly discussed.

The aim of this study was to investigate the effect of isolated lactic acid bacteria (LAB) on the quality of high moisture rye silage. Rye forage (Secale cereale L.) was harvested at the heading stage (27.3% of dry matter (DM)) and cut into approximately 3-5 cm lengths. Then, the forage divided into 4 treatments with different inoculants: 1) No additives (CON); 2) Lactobacillus brevis strain 100D8 at a 1.2 x 105 colony-forming unit (cfu)/g of fresh forage (LBR); 3) Leuconostoc holzapfelii strain 5H4 at a 1.0 x 105 cfu/g of fresh forage (LHO); and 4) Mixture of LBR and LHO (1:1 ratio) applied at a 1.0 x 105 cfu/g of fresh forage (MIX). About 3 kg of forage from each treatment was ensiled into a 20 L mini-bucket silo in quadruplicate for 100 days. After silo opening, silage was collected for analyses of chemical compositions, in vitro nutrient digestibilities, fermentation characteristics, and microbial enumerations. The CON silage had the highest concentrations of neutral detergent fiber and acid detergent fiber (p = 0.006; p = 0.008) and a lowest in vitro DM digestibility (p < 0.001). The pH was highest in CON silage, while lowest in LBR and MIX silages (p < 0.001). The concentrations of ammonia-N, lactate, and acetate were highest in LBR silage (p = 0.008; p < 0.001; p < 0.001). Propionate and butyrate concentrations were highest in CON silage (p = 0.004; p < 0.001). The LAB and yeast counts were higher in CON and LHO silages compare to LBR and MIX silages (p < 0.001). However, the mold did not detect in all treatments. Therefore, this study could conclude that L. brevis 100D8 and Leu. holzapfelii strain 5H4 can improve the digestibility and anti-fungal activity of high moisture rye silage.

Cordyceps militaris mycelium extracts containing high amounts of cordycepin were evaluated in vitro for their antiinflammatory and tumor cell growth-inhibitory activities. All extracts dose dependently inhibited the increased production of inflammatory mediators including reactive oxygen species (ROS), nitric oxide (NO), and β-hexosaminidase in lipopolysaccharide (LPS)-stimulated inflammatory cells. All extracts were evaluated for anti-proliferative activity against normal RBL-2H3 cells and diverse types of cancer cell lines, including HCT, MC5-7, U-87MG, AGS, and A549 cells. The extract showed the strongest growth inhibition (IC50 = 28.13 μg/mL) relative to vehicle-treated control cells against fibrosarcoma (MC5-7). We have demonstrated anti-inflammatory activity of C. militaris via inhibition of NO, ROS production, and β-hexosaminidase release in activated cells. C. militaris mycelium extract was also evaluated mechanistically and found to exert six types of anti-cancer activity, confirming its pharmacological potential. Our study suggests C. militaris use as a potential source of anti-inflammatory and anticancer agents. C. militaris may also be considered a functional food.

As the era of Covid-19 provoked the demand for online learning environments, research on the use of IT technologies in the teaching of Chinese is also drawing attention. This paper presents an overview of studies on mobile applications for learning Chinese in Korea, China, and the U.S.. This study aims to identify the current status of research on mobile applications for learning Chinese in Korea, and suggests directions for further research. In the review, a total of 135 studies were closely examined based on the year of publication, the subject, the method, and the research topic. After this, the features and overall flow of research in each country was identified. The necessity of revitalizing related research in Korea was highlighted. To this end, this study recommends actively conducting research, specifying the characteristics of the research subject, and extending the general process in studies of mobile applications for learning Chinese. This study expects Chinese education research on using various technologies to be further discussed.

In the past decade, there has been phenomenal progress in the field of nanomaterials, especially in the area of carbon nanotubes (CNTs). In this review, we have elucidated a contemporary synopsis of properties, synthesis, functionalization, toxicity, and several potential biomedical applications of CNTs. Researchers have reported remarkable mechanical, electronic, and physical properties of CNTs which makes their applications so versatile. Functionalization of CNTs has been valuable in modifying their properties, expanding their applications, and reducing their toxicity. In recent years, the use of CNTs in biomedical applications has grown exponentially as they are utilized in the field of drug delivery, tissue engineering, biosensors, bioimaging, and cancer treatment. CNTs can increase the lifespan of drugs in humans and facilitate their delivery directly to the targeted cells; they are also highly efficient biocompatible biosensors and bioimaging agents. CNTs have also shown great results in detecting the SARS COVID-19 virus and in the field of cancer treatment and tissue engineering which is substantially required looking at the present conditions. The concerns about CNTs include cytotoxicity faced in in vivo biomedical applications and its high manufacturing cost are discussed in the review.

The utilization of carbonaceous reinforcement-based polymer matrix composites in structural applications has become a hot topic in composite research. Although conventional carbon fiber-reinforced polymer composites (CFRPs) have revolutionized the composite industry by offering unparalleled features, they are often plagued with a weak interface and lack of toughness. However, the promising aspects of carbon fiber-based fiber hybrid composites and hierarchical composites can compensate for these setbacks. This review provides a meticulous landscape and recent progress of polymer matrixbased different carbonaceous (carbon fiber, carbon nanotube, graphene, and nanodiamond) fillers reinforced composites’ mechanical properties. First, the mechanical performance of neat CFRP was exhaustively analyzed, attributing parameters were listed down, and CFRPs’ mechanical performance barriers were clearly outlined. Here, short carbon fiber-reinforced thermoplastic composite was distinguished as a prospective material. Second, the strategic advantages of fiber hybrid composites over conventional CFRP were elucidated. Third, the mechanical performance of hierarchical composites based on carbon nanotube (1D), graphene (2D) and nanodiamond (0D) was expounded and evaluated against neat CFRP. Fourth, the review comprehensively discussed different fabrication methods, categorized them according to performance and suggested potential future directions. From here, the review sorted out three-dimensional printing (3DP) as the most futuristic fabrication method and thoroughly delivered its pros and cons in the context of the aforementioned carbonaceous materials. To conclude, the structural applications, current challenges and future prospects pertinent to these carbonaceous fillers reinforced composite materials were elaborated.

In preparation of porous carbon materials microwave oven brightening is one of the warming modes used ever. The various procedures that take place in microwave combustion process include carbonization, incitation, and recovery and thus carbon is defined. This paper compares ideal conditions of traditional warming methods, as well as their implementation potential, losses, and specifications. This porous carbon with heat treatment possesses various properties and they are well suited for energy applications which require constrained space such as hydrogen storage in solid-state and supercapacitors. The enhanced properties are chemical and thermal stability, ready availability, low framework density and ease of processability. The recent trend in class of porous carbons is Activated Carbons that are employed traditionally as adsorbents or catalyst supporters but currently, they found potent applications in fabricating for hydrogen storage materials and supercapacitors. These activated carbons are much enhanced form in class of porous carbon materials and they possess the capability to enable hydrogen economy, where the energy carrier is hydrogen. Therefore, the utility of activated carbons as a source for energy storage experiences a rapid growth at current trend and they possess significant advances. This investigation is based on detailed cost development data and electrical imperativeness applications.

Nanosized rutile titanium dioxide (TiO2) is used in inorganic pigments and cosmetics because of its high whiteness and duality. The high quality of the white pigments depends on their surface coating technique via the solgel process. SiO2 coatings are required to improve the dispersibility, UV-blocking, and whiteness of TiO2. Tetraethyl orthosilicate (TEOS) is an important coating precursor owing to its ability to control various thicknesses and densities. In addition, we use Na2SiO3 (sodium silicate) as a precursor because of its low cost. Compared to TEOS, which controls the pH using a basic catalyst, Na2SiO3 controls the pH using an acid catalyst, giving a uniform coating. The coating thickness of TiO2 is controlled using a surface modifier, cetrimonium bromide, which is used in various applications. The shape and thickness of the nanosized coating layer on TiO2 are analyzed using transmission electron microscopy, and the SiO2 nanoparticle behavior in terms of the before-and-after size distribution is measured using a particle size analyzer. The color measurements of the SiO2 pigment are performed using UV-visible spectroscopy.

To solve the pathological problems of the musculoskeletal system based on evidence, a sophisticated analysis of human motion is required. Traditional optical motion capture systems with high validity and reliability have been utilized in clinical practice for a long time. However, expensive equipment and professional technicians are required to construct optical motion capture systems, hence they are used at a limited capacity in clinical settings despite their advantages. The development of information technology has overcome the existing limit and paved the way for constructing a motion capture system that can be operated at a low cost. Recently, with the development of computer vision-based technology and optical markerless tracking technology, webcam-based 3D human motion analysis has become possible, in which the intuitive interface increases the user-friendliness to non-specialists. In addition, unlike conventional optical motion capture, with this approach, it is possible to analyze motions of multiple people at simultaneously. In a non-optical motion capture system, an inertial measurement unit is typically used, which is not significantly different from a conventional optical motion capture system in terms of its validity and reliability. With the development of markerless technology and advent of non-optical motion capture systems, it is a great advantage that human motion analysis is no longer limited to laboratories.

Prior to dismantling a nuclear facility, full site characterization should be carried out to identify basic data for various stages of decommissioning, such as deregulation of sites and structures, selection of decontamination technology, decommissioning methods, and waste management and disposal. Radiological characterization is implemented through information collection, on-site measurement, sampling and analysis, and theoretical calculations and proven codes for radioactive material at the time of decommissioning of the nuclear facility. There are issues in that it takes a lot of time and money to collect and analyze samples for characterization of contaminated sites and radioactive structures. Therefore, in the entire process of decommissioning a nuclear facility, a technology that can quickly measure the radiological characteristics of various decommissioning objects and wastes on site is required. In this project, the utilization of gamma cameras that can be analyzed in the field for quick and accurate characteristic evaluation at the dismantling site was studied. A gamma camera, iPIX from Canberra (Now it became Mirion Technology), was tested in this study. It is a unique gamma imager, which have a CdTe sensor with TIMEPIX chip and a coded aperture collimator, quickly locates and identifies low to high level radioactive sources from a distance while estimating the dose rate at the measurement point in real time. It also can be combined with CZT sensor which called iPIX-NID (nuclide Identification) provides users with clear understanding of radionuclides presence with no need of any spectroscopic knowledge. iPIX with iPIX-NID convert the gamma camera into a hot-spot detector with radionuclide information. To verify the applicability of a gamma camera in Nuclear power plant, it was implemented to Kori unit-1 which was permanently shut down from 2017. Various Systems were observed at restricted area including reactor cooling system, boron recovery system, residual heat removal system, containment spray system, and etc. The locations of hot spots were clearly revealed by iPIX and these results can be used for selecting the locations of destructive samples and help to decide the conservative decision making. Condensate water systems in turbine building were also observed by a gamma camera and showed no nuclide. Based on this preliminary gamma camera applications, further investigation and tests will be carried out to Kori Unit-1.

Dry storage cask facilities are considered for temporary storage of spent nuclear fuels before their final disposal. According to relevant domestic laws and regulations, the integrity and gross defects of the PWR spent fuel must be inspected before they are transferred to the dry cask from a wet storage pool of a nuclear power plant. To meet nuclear safeguards requirements for a spent fuel transportation, the KINAC has been working to develop a simple and convenient Non-destructive Testing (NDT) equipment to verify the integrity and gross defects of the spent fuel assembly. This study was conducted in two processes. The first stage is to review the current NDT techniques conducted in the nuclear fuel manufacturing process. During the manufacturing process, the Ultrasonic testing (UT) and Eddy Current Testing (ECT) technique are used for detecting the cracks or foreign materials in a cladding of a fresh fuel. During an over-haul period after an end of one fuel cycle, the sipping test of the spent fuel is performed for detecting the failed fuel assemblies. If it is determined through the sipping test whether any fuel assembly contains a failed fuel rod, the failed fuel rod of lots of fuel rods in the assembly is found out using the UT instrument. The ECT is used for detecting the internal defects and oxide layer thickness of a fuel cladding. Because the UT and ECT are the wellknown technique and has already been employing for the spent fuel inspection, we adopted the UT and ECT technique for development of a new instrument for nuclear safeguards verification. The second stage is to design the UT and ECT equipment in consideration of nuclear safeguards activities in the spent fuel pool. For nuclear safeguards inspection, irradiated fuel or non-fuel items are distinguished. Thus, verification equipment newly designed using the UT and ECT should detect not only a failed rod, but also a false tube, or a false rod, or a different material from a cladding. New probe and signal processing methods are developed to achieve these goals. The design of UT and ECT probes are preferentially carried out according to technical requirements – the probe thickness including a damper material should be less than 1.0 mm - and the study on analyzing signal distortion caused from material difference will be conducted for development of the safeguards inspection equipment. Detailed results of our study will be discussed in this conference.