The utilization of pig slurry (PS) as an organic fertilizer plays a pivotal role in nutrient recycling within agricultural systems. However, this practice concomitantly leads nitrogen (N) losses through ammonia (NH₃) volatilization and nitrous oxide (N₂O) emissions. The objective of this study was to investigate the effect of wood biochar on mitigating NH3 and N2O emissions and enhancing N retention from PS-applied soil, and plant biomass production during the vegetative growth of rapeseed (Brassica napus L.). The experiment consisted of three treatments: 1) water (non-PS), 2) PS, and 3) PS combined with wood biochar (PS+WB). The PS+WB treatment resulted in the maintenance of elevated soil water content during the experimental period. The PS+WB treatment significantly enhanced soil nitrogen retention compared to PS alone, maintaining higher total N and NH₄⁺-N levels while reducing NO₃⁻ -N accumulation. Wood biochar application also leds to substantial reductions in NH₃ and N₂O emissions, mitigating environmental N losses. The PS+WB treatment resulted in an improvement of shoot biomass, crude protein content, and total digestible nutrients, indicating enhanced forage quality. The increased soil moisture content in PS+WB further contributed to plant growth benefits. These findings demonstrate that wood biochar is an effective amendment for improving nitrogen retention, reducing gaseous N emissions, and enhancing crop productivity in PS-amended soils.

목적 : 본 연구는 세륨(IV)-지르코늄(IV) 산화물 나노입자를 사용하여 콘택트렌즈를 제조한 후, 안의료용 기능성 렌즈로의 사용 가능을 확인 위해 제조된 렌즈의 물성을 비교 분석하였다. 방법 : 2-Hydroxyethyl methacrylate에 나노 세륨-지르코늄 산화물(cerium(IV)-zirconium(IV) oxide)을 첨가하여 공중합 한 후 물성을 측정하고, 친수성 단량체인 methacrylic acid(MA)를 추가로 첨가하여 물성을 측정, 비교하였다. 결과 : 다양한 비율의 세륨(IV)-지르코늄(IV) 산화물 나노입자와 MA를 첨가한 렌즈의 물성을 평가한 결과, UV-B 투과율은 40.95~66.26%, 굴절률 1.4163~1.4357, 함수율 37.44~47.18%, 접촉각 36.87~56.36°, 인장 강도 0.0612~0.561 kgf/mm², 표면거칠기 7.70~8.72 nm로 각각 측정되었다. 나노입자 및 MA 첨가는 습윤성, 인장강도 및 중합안정성을 향상시키고, UV-B 투과율과 표면거칠기를 감소시켰으며, 황색포도상구균에 대한 항균 성이 확인되었다. 결론 : 세륨(IV)-지르코늄(IV) 산화물 나노입자에 MA를 첨가하여 제조한 렌즈가 중합 안정성, 내구성, 습윤성 을 향상시키는 것을 확인하였으며, 따라서 안의료용 기능성 콘택트렌즈 소재로 활용할 수 있을 것으로 판단된다.

This study focuses on analyzing the impact range of toxicity, overpressure and radiant heat (pool fire and boiling liquid expanding vapor explosion, BLEVE) resulting from a propylene oxide leakage accident and proposes mitigation strategies to minimize damage. A risk assessment was conducted by designing accident scenarios based on variables such as substance quantity and wind speed. The results indicated that toxicity and BLEVE were the primary risk factors, and the risk level increased as the substance quantity increased and wind speed decreased. For future mitigation strategies, it is suggested that a quantitative analysis of vapor dispersion rates and dilution and effects under various environmental conditions be conducted, along with preliminary research on optimizing absorbents and catalytic materials.

As the pace of technological advances accelerates, the role of electrical energy storage has become increasingly important. Among various storage solutions, supercapacitors are garnering significant attention. Their unique attributes, including high power density, rapid charge/discharge capabilities, and extended lifecycle, position them as a promising alternative to conventional batteries. This study investigates the synthesis of a nickel oxide (NiO) and nickel oxide/graphene oxide (NiO/GO) composite using a single-step hydrothermal method, to evaluate their potential as supercapacitor electrode materials. The synthesized NiO, graphene oxide (GO), and NiO/GO composite were comprehensively characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy to analyze their crystal structures and chemical bonding. The XRD analysis confirmed the formation of an NiO phase with a rhombohedral crystal structure, and no change after GO incorporation. SEM analysis revealed the formation of spherical NiO particles and porous morphology of the NiO/GO composite, which also exhibited a spherical shape. The GO displayed a randomly arranged wrinkled sheet-like structure. Electrochemical analysis of the NiO/GO composite exhibited a remarkable specific capacitance of 893 F g-1 at a current density of 1 A g-1, surpassing that of NiO and GO alone, demonstrating NiO/GO has promising performance for supercapacitor applications. The charge transfer resistance, derived from the Nyquist plot, suggests that the reduction in charge transfer resistance contributed significantly to the improved capacitance. Additional stability studies of over 5,000 cycles at 5 A g-1 revealed an 85 % initial capacitance retention, confirming the advantages of GO inclusion to improve material retention for superior long-term performance. The asymmetric supercapacitor (ASC) assembled using an electrode with the configuration NiO/GO//activated carbon (AC) showed a specific capacitance of 77.8 F g-1 obtained at a current density of 0.5 A g-1.

Hydrogen production via photoelectrochemical water splitting relies on the effectiveness of the photoelectrodes. Preparing low-dimensional structures of oxide semiconductors is a promising approach to fabricating effective photoelectrodes, by enhancing the surface-to-volume ratios of the photocatalytic materials. In this study, we performed a comparative investigation of the photoelectrochemical characteristics of p-type oxide semiconductor cupric oxide (CuO) photocathodes based on CuO thin film and nanorods. The CuO thin film was prepared via a facile method involving sputtering a Cu metallic film and subsequent thermal oxidation, while the CuO nanorods were grown via a seed-mediated hydrothermal synthesis method using a CuO nanoparticle seed layer. The structural, optical, and photoelectrochemical properties of the prepared CuO thin film and nanorods were comparatively examined. Our results confirmed that the CuO nanorod photocathode has a higher photocurrent density and better photoconversion efficiency than the CuO thin film photocathode for photoelectrochemical water splitting, implying a promising route to the fabrication of CuO-based photoelectrodes.

Iron oxide (ε-Fe2O3) is emerging as a promising electromagnetic material due to its unique magnetic and electronic properties. This review focuses on the intrinsic properties of ε-Fe2O3, particularly its high coercivity, comparable to that of rare-earth magnets, which is attributed to its significant magnetic anisotropy. These properties render it highly suitable for applications in millimeter wave absorption and high-density magnetic storage media. Furthermore, its semiconducting behavior offers potential applications in photocatalytic hydrogen production. The review also explores various synthesis methods for fabricating ε-Fe2O3 as nanoparticles or thin films, emphasizing the optimization of purity and stability. By exploring and harnessing the properties of ε-Fe2O3, this study aims to contribute to the advancement of next-generation electromagnetic materials with potential applications in 6G wireless telecommunications, spintronics, high-density data storage, and energy technologies.

The heat transfer characteristics of double-pipe spiral heat exchanger using aluminum oxide nano-fluid were investigated by three different sizes of curvature size, experimentally. Five concentration of nano-fluid as working fluid were made and tested to analyze the heat transfer characteristics. As results, the heat transfer performance was improved at 0.25% of nano-fluid due to high thermal conductivity, however, as the concentration of nanofluid increased (~2.0%), the heat transfer performance deteriorated due to the increase in thermal resistance caused by the sedimentation of particles in the flow path. In addition, the nano-fluid has a higher pressure drop than water due to its high density and viscosity. The optimal range for heat transfer enhancement of nano-fluid was found to be less than 4.0 LPM in flow rate and 0.25% of nano-fluid concentration in this study.

본 연구에서는 산화 방지 특성이 있는 가려진 페놀기를 도입한 산화 그래핀(hindered phenol-grafted graphene oxide, HP-GO)을 합성한 후 탄화수소계 고분자인 sulfonated poly(arylene ether sulfone) (SPAES)을 기지체로 사용한 복합 막을 제조하여 고분자 연료전지 시스템에 응용하고자 하였다. HP-GO는 GO 표면의 하이드록시기(hydroxy group)와 HP의 염화 카 보닐(carbonyl chloride) 간의 친핵성 아실치환 반응을 통해 합성되었으며, HP-GO의 비율을 다르게 첨가한 복합 막을 제조한 후 선형 SPAES 막과의 비교를 통해 성능 특성 변화를 확인하였다. 특정 함량의 HP-GO를 첨가한 복합 막의 경우 선형 SPAES 막에 비해 체적 안정성과 기계적 강도 및 수소 이온 전도도가 증가된 것을 확인할 수 있었으며, 펜톤 평가(Fenton’s test) 진행 후 막 분해 시간 및 잔여 막 무게 비율이 증가되는 경향을 통해 화학적 내구성 역시 증가한 것을 확인할 수 있었다.

With the continuing advances in technology, electrical energy storage has become increasingly important. Among storage devices supercapacitors’ distinct qualities, such as a long lifespan, quick charge/discharge speeds, and high-power density, make them viable substitutes for traditional batteries. In this study a simple hydrothermal method was used to synthesize a h-MoO3/graphene oxide (GO) composite for such applications. The crystal structure, morphology, and chemical bonding were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Raman spectroscopy. XRD confirmed the hexagonal crystal structure, and no changes were observed after GO incorporation. The FESEM images revealed that the nanosheets of GO and hexagonal rods MoO3 were well coupled with the GO sheets. The electrochemical properties of the pure h-MoO3 and h-MoO3/GO composites were studied using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The nanocomposite electrode demonstrated a specific capacitance of 134 Fg-1 at a current density of 3 mA/cm-2, an energy density of 26.8 Wh/kg-1, and power density of 560 W/kg-1 in an aqueous acidic electrolyte 1 M H2SO4, which is notably higher than that of pure MoO3. This indicates the promising electrochemical performance of MoO3/GO composite for supercapacitor applications. The enhanced capacitive performance may have resulted from the decrease in the charge transfer resistance (Rct), calculated from the Nyquist plot. Furthermore, the composite material exhibited stability and a capacitive retention of 76 % after 1,000 cycles. This confirms the benefits of incorporating GO to enhance material retention for better long-term results. The results of this study demonstrate its potential to advance energy storage technology. Maintaining the hexagonal crystal structure of h-MoO3 while incorporating GO improves the composite’s structural stability, an important factor for reliable long-term use. Moreover, the observed reduction in crystallite size due to the presence of GO suggests improved electrochemical performance.

The feeder pipes of the primary cooling system in a pressurized heavy water reactor (PHWR) are composed of carbon steel SA 106 GR.B. On the surface of this structural material, corrosion oxide layers including radionuclides are formed due to the presence of active species from water decomposition products caused by radiation, as well as the high temperature and high-pressure environment. These oxide layers decrease the heat transfer efficiency of the primary cooling system and pose a risk of radiation exposure to workers and the environment during maintenance and decommissioning, making effective decontamination essential. In this study, we simulated the formation of the corrosion oxide layer on the surface of carbon steel SA 106 GR.B, characterized the formed corrosion oxide layer, and investigated the dissolution characteristics of the corrosion oxide layer using oxalic acid (OA), a commercial chemical decontamination agent. The corrosion oxide layer formed has a thickness of approximately 4 μm and consists of hematite ( Fe2O3) and magnetite ( Fe3O4). The carbon steel coupons with formed oxide layers were dissolved in 10 mM and 20 mM OA solutions, resulting in iron ion concentrations of 220 ppm and 276 ppm in the OA respectively. In 10 mM and 20 mM OA, the corrosion depths of the coupons were 8.93 μm and 10.22 μm, with corrosion rates of 0.39 mg/cm2·h and 0.45 mg/cm2·h, respectively. Thus, this demonstrates that higher OA concentrations lead to increased dissolution and corrosion of steel.

Lithium-ion batteries are widely used in various advanced devices, including electric vehicles and energy storage devices. As the application range of lithium-ion batteries expands, it will be increasingly important to improve their gravimetric and volumetric energy density. Layer-structured oxide materials have been widely adopted as cathode materials in Li-ion batteries. Among them, LiNiO2 has attracted interest because of its high theoretical capacity, ~274 mAh g-1, assuming reversible one Li+-(de)intercalation from the structure. Presently, such layered structure cathode materials are prepared by calcination of precursors. The precursors are typically hydroxides synthesized by coprecipitation reaction. Precursors synthesized by coprecipitation reaction have a spherical morphology with a size larger than 10 μm. Spherical precursors in the several micrometer range are difficult to obtain due to the limited coprecipitation reaction time, and can lead to vigorous collisions between the precursor particles. In this study, spherical and small-sized Ni(OH)2 precursors were synthesized using a new synthesis method instead of the conventional precipitation method. The highest capacity, 170 mAh g-1, could be achieved in the temperature range of 730~760 °C. The improved capacity was confirmed to be due to the higher quality of the layered structure.