Gas sensors play a crucial role in monitoring harmful gas concentrations and air quality in real-time, ensuring safety and protecting health in both environmental and industrial settings. Additionally, they are essential in various applications for energy efficiency and environmental protection. As the demand for hydrogen refueling stations and hydrogen fuel cell vehicles increases with the growth of the hydrogen economy, accurate gas concentration measurement technology is increasingly necessary given hydrogen's wide explosion range. To ensure safety and efficiency, gas sensors must accurately detect a wide range of gas concentrations in real-world environments. This study presents two types of gas sensors with high sensitivity, stability, low cost, fast response time, and compact design. These sensors, based on volume and pressure analysis principles, can measure gas filling amounts, solubility, diffusivity, and the leakage of hydrogen, helium, nitrogen, and argon gases in high-density polyethylene charged under high-pressure conditions. Performance evaluation shows that the two sensors have a stability of 0.2 %, a resolution of 0.12 wt･ppm, and can measure gas concentrations ranging from 0.1 wt･ppm to 1400 wt･ ppm within one second. Moreover, the sensitivity, resolution, and measurement range of the sensors are adjustable. Measurements obtained from these sensors of gas filling amounts and the diffusivity of four gases showed consistent results within uncertainty limits. This system, capable of real-time gas detection and characterization, is applicable to hydrogen infrastructure facilities and is expected to contribute to the establishment of a safe hydrogen society in the future.

Many recent research efforts have focused on developing high-performance wearable health monitoring systems. This work presents a mechanically stretchable and skin-mountable sensor system based on a conductive polymer composite-based elastic printed circuit board (EPCB) in which a resistive-type composite strain sensor is monolithically integrated. The composite-based EPCB is simply prepared by patterning a silver nanowire (AgNW)/dragon skin (AgNW/DS) composite film in a programmable manner using a direct cut patterning technique. The proposed sensor system was successfully fabricated by directly mounting various components (e.g., microcontroller, circuit elements, light emitting device chips, temperature sensor, Bluetooth module) on the prepared AgNW/DS-based EPCB. The fabricated sensor system was found to be highly stretchable and rollable enough to maintain tight adhesion to the wrist region without significant physical deterioration, even when the wrist was in motion. The wireless sensor system attached to the wrist part enabled us to monitor the wrist motion and surrounding temperature in real time, opening the possible application as a wearable health monitoring platform.

The structural, thermal, and electrical characteristics of the superconducting Bi2Ba2Ca2Cu3O10+δ compound are the main subjects of this work. The solid-state reaction (SSR) method was used to prepare the samples. The samples were placed in a furnace and heated at 820 °C for 70 hours at a heating rate of 5 °C/min. X-ray diffraction (XRD) studies were then performed on the prepared samples. XRD results revealed an orthorhombic crystal structure with variations in the lattice constants a, b, and c (where a = 5.416, b = 5.432, and c = 36.5 Å). The highest superconducting transition phase fraction (HTP%) was 78.76 %. The composition and morphology of the superconducting compound were studied using a scanning electron microscope (SEM). Images were taken at 20 kX magnification, where we observed nanoparticles with a size of 86.65 nm had formed. The elemental analysis of the sample was conducted with energy-dispersive X-ray spectroscopy (EDS), and the results showed the presence of different elements and their proportions for each sample. Thermal conductivity was also measured and it was found that the sample conductivity increased with increasing temperature. The electrical resistivity was examined, and it was observed that the resistivity decreased as the sample was cooled. The results showed that the highest initial critical temperature was 131 K, while the zero critical temperature was 114 K.

Magnetic nanoparticles in nanofluid have a unique ability in that they can be influenced by an external magnetic field, making them a promising heat-exchanging fluid to meet the demands of highly efficient thermal systems. The parametric impact of the magnetic field (static and time-varying) on the heat exchanging rate of Fe3O4 nanoparticles and water-based ferrofluid was investigated in this study. The experimental setup for generating a variable frequency magnetic field and analyzing the thermal behavior of ferrofluid is presented. Temperature data was obtained as heat is transferred from heated water to the ferrofluid used as a coolant. An enhancement of the heat transfer of the magnetic nanofluid was observed when varying the magnetic field frequency, through experimental analysis. The concentration of Fe3O4 nanoparticles in the ferrofluid was varied (0.5 wt%, 1 wt%)to study the impact of nanoparticle loading on heat transfer. An alternative approach for controlling the heat exchange rate in thermal systems is proposed, utilizing the magnetic tunability of the ferrofluid.

This paper focuses on methods for quantifying landfill gas emissions, including odor, odor generation mechanisms, odor emission characteristics according to the time of waste deposition, and odor measurement data from landfills. This study analyzed the concentration ranges and median values of 22 odor compounds measured at landfill gas collection wells and various landfill surface locations across both domestic and international landfill sites. These locations included active operational areas, final cover surfaces, and leachate treatment zones. The odor with the highest measured concentration at the landfill gas collection well was H2S (with a median value of 818,616 mg m–3). During landfill operations and on the surface of uncovered landfill layers, the concentrations of NH3 (with a median value of 1,613 mg m–3) and H2S (with a median value of 279.5 mg m–3) were found to be high . Concentrations of toluene, xylene, ketones, and sulfide odors were also high at covered landfill surfaces. Additionally, NH3, styrene, and H2S had high concentrations in the leachate treatment area. The odor intensity, measured on the surface of covered sanitary landfills for domestic waste, ranged from 6 to 2,080 mg m–3 (dilution to threshold). The concentrations of NH3 and H2S were relatively high in domestic sanitary landfills. The odorous compounds that contributed the most to odor intensity were nitrogen-containing odors, sulfur-containing odors, and aldehydes. In order to effectively manage landfill odors in the future, research should be continuously conducted to accurately measure and predict odor emission fluxes from landfills. In addition, it will be necessary to develop emission reduction technologies that take into account landfill odor emission characteristics.

This study analyzed the emission characteristics of major air pollutants (dust, nitrogen oxides, hydrogen chloride, and carbon monoxide) emitted from domestic public waste incineration facilities based on their operating elements. Using automatic measuring equipment for smokestacks (TMS), data was collected from 97 facilities from 2015 to 2023. The emission source unit (kg/ton) was evaluated based on the facility’s capacity, aging level, and incineration type. Emissions were calculated, and descriptive statistical analysis was performed based on the mean, standard deviation, and coefficient of variation. As a result of the analysis, it was found that the larger the facility capacity, the lower the average emission and volatility, which suggests that the operational stability of large facilities is high. On the other hand, facilities that had deteriorated for 10 to 15 years had the highest emission rates, and emissions decreased in facilities that were aged more than 20 years. In addition, the pyrolysis and high-temperature melting incineration facilities had lower NOx and HCl emissions than the conventional incineration type. Furthermore, CO showed the greatest volatility overall, which was found to be particularly difficult to manage in facilities in the early to mid stages of aging. These results provide empirical evidence that the structural characteristics and incineration type of incineration facilities have a significant impact on air pollutant emissions and can serve as useful basic data for policy-making, including for implementing region-wide initiatives and planning major repairs in the future.

This study examined the influence of multiple factors—particularly occupant presence and air purifier operation—on indoor PM2.5 concentrations across 104 households in the Seoul metropolitan area. Both indoor and outdoor PM2.5 concentrations were continuously monitored and integrated with time-specific survey data to analyze spatial and temporal patterns of indoor exposure. Results showed that occupant presence significantly elevated indoor PM2.5 concentrations, especially during periods of high activity (08:00~15:00 and 18:00~20:00). The indoor/outdoor (I/ O) concentration ratio was also significantly higher during these periods, indicating that occupant activities were a major contributor to indoor PM2.5 concentrations. Air purifier use was found to be associated with a consistent reduction in indoor PM2.5 concentrations, regardless of occupancy status. Notably, the I/O ratio also decreased when air purifiers were in operation, demonstrating their effectiveness in controlling both indoor emissions and the infiltration of outdoor pollutants. These findings provide empirical evidence of the multifactorial dynamics governing indoor PM2.5 exposure and highlight the importance of occupant-centered and time-specific strategies for effective residential air quality management.

This study aims to examine the validity of current environmental safety standards and propose necessary improvements to minimize health risks posed by heavy metals in children’s activity zones. Compared to adults, children are more vulnerable to hazardous substances, and exposure to heavy metals can severely impact their neurological development and physical growth. In Korea, the amendment of the Enforcement Rules of the Environmental Health Act (Annex 4-20) in July 2021 reduced the acceptable threshold for lead (Pb) in paints and finishing materials used in children’s activity zones. However, regulatory standards for other heavy metals remain insufficient. Therefore, this research investigates and analyzes both domestic and international standards for heavy metals in commonly used materials such as wallpaper, flooring, finishing materials, and paints. This paper proposes guidelines for improving current regulatory criteria based on scientific validity and potential exposure. The findings are expected to serve as foundational data for advancing proactive environmental safety management strategies to better protect children’s health.

This study examined the simultaneous application of absorption and adsorption by adding granular activated carbon to tap water (Absorbent-A) and sodium hypochlorite (Absorbent-B), with the aim of improving the removal performance of gaseous acetaldehyde applying hybrid process. Prior to the main experiment, preliminary tests were conducted to assess the effects of HOCl concentration (50~150 ppm) and reactor temperature (25~35oC). In the main experiment, the removal performance under activated carbon-added conditions was compared using the concentration ratio (Co/ Ci) and its rate of change over time. As a result, the addition of activated carbon led to a more gradual saturation and concentration change compared to the non-addition condition, with the addition showing the most stable trend. This study suggests a basic reference for improving the performance of conventional absorbents enhancing the durability and efficiency with the activated carbon as an auxiliary material for future field applications.

This study aims to enable early detection of low-concentration airborne respiratory viruses in multi-use facilities using a cyclone-based air sampler (Coriolis® m , Bertin). To achieve this, bacteriophage MS2 of Escherichia coli was aerosolized into a chamber at varying concentrations, reflecting levels observed in indoor environments. The rationale for differentiating viral concentrations was to assess field applicability and optimize sampling conditions. Sampling efficiency was maximized by adjusting sampling time, flow rate, and media volume to determine optimal detection parameters. The effectiveness of the optimized conditions was further validated through cross-validation using Influenza A and field testing. Field experiments conducted on 10 samples across five locations confirmed airborne virus detection in one of the samples (10%), demonstrating the feasibility of the cyclone-based air sampler method for airborne virus collection and detection.

Volatile fatty acids (VFAs) are designated as offensive odor substances, and they are known for their strong polarity and adsorptive properties, which can lead to significant losses during sample collection and analysis. This study evaluates two analytical methods currently outlined in the odor process test standards, alongside an analytical system utilizing adsorption tubes and another system that uses ion chromatography (IC). Furthermore, suitable analytical methods were proposed for analyzing concentrations below the odor threshold and emission limits. When assessing SPME-GC/FID, SPME-GC/MSD, TD-GC/MSD, and IC based on the internal quality control standards specified in the process test standards, all methods were found to have met these criteria. The absolute injection amounts (1 atm, 25oC) satisfying the emission limits ranged from 3 to 95 ng, while those that met the odor thresholds ranged from 0.2 to 6.5 ng. Based on these criteria, analytical systems suitable for the specified concentration range and odor thresholds were identified. The results are as follows. 1. The analytical systems confirmed to be suitable for quantifying limits were TD-GC/ MS and IC. 2. In terms of recovery and precision, both TD-GC/MSD and IC were found to be suitable. 3. Regarding detection limits, both previously mentioned systems were satisfactory. 4. Finally, concerning quantitation limits, both systems were adequate; however, TD-GC/MSD slightly exceeded the odor threshold analysis range for propionic acid by approximately 1.5 ng. The odor thresholds for the four VFAs were converted to absolute quantities (1 atm, 25oC), confirming that the IC system met the following criteria: (1) calibration range and curve, (2) accuracy and precision, and (3) instrumental detection and quantitation limits.

이 글은 통일 이후 북한지역의 고용정책을 수립함에 있어 근로권과 재 산권의 규범원리가 어떠한 방식으로 작동해야 하는지를 남북한 법제도 비교를 통해 고찰하였다. 북한은 노동을 국가의 의무로 규정하고, 직업의 배치와 관리를 국가가 독점하는 통제 중심의 체제를 유지하고 있는 반면, 남한은 직업 선택의 자유와 노동시장의 자율성을 전제로 고용제도를 운 영하고 있다. 이러한 체제 간 근본적인 차이를 충분히 고려하지 않은 채, 남한의 보 편적 노동관련 법제를 일방적으로 북한지역에 적용할 경우, 북한 주민의 실업문제를 구조적으로 심화시키고, 사회경제적 혼란을 초래할 가능성이 있다. 이에 본 연구는 근로권과 재산권을 상호 분리된 개별권리가 아니라, ‘일할기회’와 ‘생계기반’을 포괄하는 통합적 권리로 접근할 필요성을 제기 한다. 고용을 자산형성과 연계하는 제도적 방향은, 북한 주민의 자립 영 향을 강화하고 안정적인 노동시장 질서를 기초를 수립하는 데 기초가 되 기 때문이다. 이러한 통합적 접근은 단기적 실업해소에 그치는 것이 아니 라, 통합과정에서의 지속가능한 사회통합에 기여할 수 있을 것이다.

This study evaluated the field applicability of a real-time odor monitoring system combined with ozone water spraying technology to effectively control odors generated in livestock manure recycling facilities. Research was conducted at a Natural Circulation Agriculture Center located in N City, where concentrations of ammonia (NH3), hydrogen sulfide (H2S), and volatile organic compounds (VOCs) were measured in real time. Based on real-time data, ozone water was sprayed to assess the odor reduction rate, and the impact on surrounding areas was predicted through odor dispersion modeling. The results showed that the ammonia concentration measured at the upper section of the liquid aeration tank before ozone water spraying was 8.02 ppm, exceeding the emission limit of 1 ppm. VOCs were also found to have significantly contributed to odor generation. However, after spraying ozone water at a rate of 7 L/min and maintaining a concentration of 2.5 mg/L, ammonia was reduced by approximately 50%, and VOCs were reduced by about 98%, demonstrating a strong odor-reducing effect. Odor dispersion modeling using the CALPUFF modeling system simulated the range of odor dispersion before and after ozone water spraying. The results indicated that after ozone water spraying, the ammonia concentration at the facility boundary met the emission limit, effectively suppressing odor dispersion. In particular, the ozone water spraying system linked with the real-time sensor enabled automated odor control based on real-time data, demonstrating its potential for resolving odor complaints and ensuring compliance with environmental regulations.

이 글은 반폐쇄해인 태국만에서 한 세기 이상 지속되어 온 태국-캄보디 아 간 해양 분쟁의 복잡한 연원과 해양경계 협상을 살펴보고, 대륙붕 공동 개발 등 양국 간 해양 분쟁 관리의 핵심적 틀로 여겨지는 2001년 ‘해양경계획정 및 공동개발체제 수립에 관한 양해각서(MoU44)’의 쟁점 과 법적 성질을 규명하는 것을 목적으로 한다. 양국 간 국경분쟁은 1907년 프랑스-샴 조약과 부속 지도에 대한 해석에 서 비롯되었다. 1907년 부속 지도는 양국 간 합의로 프랑스 지도회사가 제 작한 것으로, 육상 경계는 자연 분수령을 따르기로 하였다. 프레아 비헤아 르 사원이 캄보디아 영토로 표기되었다는 점에 대해 태국이 이의를 제기하 면서, 양국 모두 영유권을 주장하는 지역이 생겨났다. 1962년 국제사법재 판소는 이 사원이 캄보디아에 속한다고 판정하였고, 2013년 사원 주변 지 역에 대해서 1962년 결정을 재확인하였다. 그러나 양국 간 육상 영토 분쟁 은 현재에도 이어지고 있다. 양국 간 해상 분쟁은 1907년 부속 지도상 꼬꿋섬(Koh Kut)과 연결된 선에 대한 상반된 해석에서 비롯되었다. 캄보디아는 이 선을 해양 경계선으 로 보면서 꼬꿋섬에 대한 영유권을 주장하였다. 태국은 이를 육상 국경 설 정을 위한 시야선으로 보았고, 실효적 지배를 근거로 영유권을 주장하였다. 1972년 캄보디아가 과도한 직선기선을 선포하여 주장중첩수역(OCA)을 형 성하면서 분쟁은 격화되었다. 태국만 내 약 26,000㎢에 달하는 OCA는 막 대한 양의 탄화수소 자원이 매장되어 있을 것으로 추정되어서 양국 간 첨 예한 대립의 원인이 되었다. 양국의 타협 없는 주장으로 인해 해양경계획정 협상은 결국 교착 상태에 빠지게 되었다. 이러한 교착 상태를 타개하기 위해 2001년 체결된 MoU44는 이원적 접 근법(Dual Track Approach)을 채택하였다. 이는 OCA 북부 지역의 경계 획정과 자원이 풍부한 남부 지역의 공동 개발을 동시에 추진하는 것을 핵 심으로 한다. 그러나 MoU44의 가장 큰 실패 요인이자 근원적 한계는 불 가분 패키지(Indivisible Package) 조항이라고 할 수 있다. 이 조항은 두 트랙의 합의가 연계되어서, 어느 한쪽의 합의 없이는 다른 쪽 합의도 효력을 발휘될 수 없도록 규정하였다. 결국 양국 간 현실적으로 해결이 어려운 꼬꿋섬 영유권 및 해양경계획정 문제로 인하여 실용적 협력이 가능한 공동 개발 논의가 발목 잡히면서, 불가분 패키지는 MoU44 체제 전체를 마비시 키는 구조적 요인으로 작용하였다. MoU44는 최종적 권리·의무를 확정하는 실체적 조약이 아니라, 합의 도출을 목표로 하는 ‘향후 합의를 위한 의사표시’(agreement to agree) 로서의 법적 성질이 강하다. 한편으로 MoU44는 양국에 UNCLOS 제74 조 및 제83조에 규정된 ‘잠정조치 의무’를 구체화하는 법적 의미를 지 닌다. 즉, MoU44는 양국에 실질적인 잠정 약정(공동 개발 등) 체결을 위해 ‘신의성실하게 교섭할 절차적 의무’를 부과하고, 최종 합의를 위태 롭게 하는 일방적 행위(자원 탐사 및 개발 등)를 삼가야 할 ‘자제 의 무’를 강화하는 역할을 한다. 결론적으로 MoU44는 분쟁의 근본 원인을 해결하지 못한 채 오히려 불 가분 패키지라는 조항으로 인해 UNCLOS상의 잠정조치 의무 이행마저 형 해화시키는 결과를 초래한 것으로 평가할 수 있다. 따라서 향후 분쟁 해결 을 위해서 양국은 경직된 일괄 타결 조항에서 벗어나, 태국-말레이시아 공 동 개발 사례처럼 경계획정 문제를 잠정적으로 유보하고 공동 개발을 우선 추진하는 유연한 접근법을 모색하거나, 동티모르-호주 사례처럼 제3자 개 입을 통한 해결 방안을 적극적으로 고려해 볼 필요가 있다. 아울러 이 사례 는 한·일 대륙붕 공동개발협정의 미래에도 중요한 시사점을 제공할 수 있으 며, 한·일 해양경계협정에 대비한 철저한 준비의 필요성을 역설해 주고 있 다.

The success of artificial insemination (AI) in the swine industry relies on conserving the quality of boar sperm during liquid storage, as boar spermatozoa are prone to oxidative stress due to the high polyunsaturated fatty acid content and lack of antioxidant defenses. Sperm motility, viability, acrosome integrity, and DNA stability are all affected by the increases in reactive oxygen species (ROS) during storage, which lowers fertility. Ethyl pyruvate (EP), a stable derivative of pyruvate, has good antioxidant properties and has been shown to protect sperm quality in vivo. Its effects on boar sperm during in vitro preservation have not yet been investigated. This study investigated the effect of different concentrations of EP (0.1–1 mM) in Beltsville thawing solution at 17°C on the sperm quality parameters of boar spermatozoa over five days. Changes in sperm motility, viability, acrosome integrity, chromatin stability, and ROS were observed. The results showed that boar spermatozoa stored with 0.25–0.75 mM EP showed a significant increase in sperm motility, viability, acrosome integrity, and chromatin stability compared with the control (without EP) and 1 mM EP for 5 days. Compared to the control and 1 mM EP, ROS levels statistically decreased in sperm stored in 0.25–0.75 mM EP on both storage days 3 and 5. Our findings demonstrated that 0.25–0.75 mM of EP could enhance the boar sperm quality and mitigate the oxidative stress during liquid storage, thus revealing a strategy to improve fertility rates during AI in pig production.

Human dermal fibroblasts (HDFs) play a critical role in maintaining skin integrity and promoting tissue repair, but are highly susceptible to apoptosis under stress conditions such as nutrient deprivation. Adipose-derived stem cells (ADSCs) have emerged as a promising therapeutic option due to their regenerative potential and ability to secrete bioactive factors. In this study, we investigated the effect of ADSC-derived paracrine signaling on apoptosis in HDFs and explored the underlying molecular mechanisms. Using a Transwell co-culture system, we found that ADSCs significantly reduced apoptosis in HDFs subjected to low-serum stress, as confirmed by APOPercentage™ staining and the expression of apoptosis-related proteins. Among several soluble factors secreted by ADSCs, hepatocyte growth factor (HGF) exhibited the most pronounced time-dependent increase in culture supernatants. The anti- apoptotic effect of ADSCs was abolished by neutralizing antibodies against HGF, indicating a key role of this factor in mediating fibroblast survival. Further, HDFs were found to express the HGF receptor c-Met at both the mRNA and protein levels. Inhibition of c-Met signaling reversed the cytoprotective effect of ADSCs, suggesting that HGF functions through this receptor. Mechanistically, only the PI3K/AKT pathway—among the major survival pathways tested—was selectively activated in HDFs by ADSC co-culture. Pharmacological inhibition of PI3K/AKT signaling using LY294002 abolished the protective effect, while inhibition of ERK or p38 MAPK had no significant impact. These findings demonstrate that ADSC-derived HGF protects HDFs from stress-induced apoptosis primarily through activation of the c-Met–PI3K/ AKT pathway. This mechanistic insight may provide a basis for the development of stem cell– based therapies aimed at enhancing skin regeneration and fibroblast viability in degenerative or wound-healing contexts.

Targeted protein degradation (TPD) is an emerging therapeutic strategy that leverages the natural protein degradation systems of cells to eliminate disease-associated proteins selectively. Unlike traditional small molecule inhibitors, which merely suppress protein activity, TPD degrades target proteins directly, offering a novel approach to addressing undruggable proteins. The two most extensively studied TPD technologies, proteolysis-targeting chimeras (PROTACs) and molecular glues (MGs), utilize the ubiquitin–proteasome system to induce TPD. PROTACs function as bifunctional molecules that recruit an E3 ubiquitin ligase (E3 ligase) to a target protein, leading to its ubiquitination and subsequent degradation, while MGs enhance protein–protein interactions to facilitate ubiquitination and protein clearance. These approaches have shown promising therapeutic potential in treating cancer, neurodegenerative disorders, and autoimmune diseases, with several compounds currently undergoing clinical trials. Despite these advances, challenges such as limited bioavailability, pharmacokinetic constraints, and target selectivity remain obstacles to the widespread application of TPDbased therapies. Recent developments, including the discovery of novel E3 ligases, linker optimization, and AI-driven drug design, have addressed these limitations, paving the way for the next generation of precision-targeted therapeutics. This paper provides a comprehensive overview of the mechanisms, applications, and future directions of PROTACs and MGs in drug discovery, highlighting their potential to revolutionize modern targeted therapy.

본 연구는 디지털 전환과 팬데믹 이후의 의료환경 변화 속에서 온라인 약 국 제도의 도입 가능성과 입법적 과제를 법학적 관점에서 분석한 것이다. 현 행 「약사법」은 의약품의 대면 판매를 원칙으로 하여 온라인 유통을 원천적으 로 제한하고 있으나, 소비자 수요와 디지털 헬스케어 환경의 확대는 제도 정 비의 필요성을 제기하고 있다. 이에 본 논문은 온라인 약국의 개념과 운영 주 체를 유형화하고, 미국, 일본, 유럽연합의 입법례를 비교 분석하였다. 또한 온 라인 약국 도입에 따라 발생하는 건강권과 공공보건의 조화, 약사 직역 보호 와 복약지도 재구성, 소비자 보호와 정보 비대칭 해소, 플랫폼 책임법제 등의 주요 법적 쟁점을 검토하였다. 이러한 분석을 바탕으로, 약사법, 전자상거래 법, 개인정보 보호법 등의 정합적 개정을 통한 법체계 정비와 더불어, 실질적 법적 책임 구조 설계, 인증제도 도입, 기술 기반 인프라 구축을 포함한 입법 적 과제를 제시한다. 본 연구는 온라인 약국 제도가 단순한 유통방식의 변화 가 아니라 보건의료체계 전반의 구조적 전환임을 전제로, 공공성과 안전성을 균형 있게 고려한 실천적 입법 대안을 도출하고자 한다.

We present an atomistic investigation of the oxygen activation of a Pt nanoparticle with 147 atoms (Pt147), focusing on the role of microfacets. Using density functional theory (DFT) calculations, we evaluated the adsorption energy (Ead) of both molecular and atomic oxygen across the surface, along with the activation energy barrier (Eact) for O2 dissociation and subsequent atomic oxygen diffusion. The Pt147 exhibited a facet-dependent variation in O2 adsorption, while atomic oxygen displayed a relatively uniform Ead across the surface. This suggests that atomic oxygen can readily participate in surface reactions regardless of the location. The diffusion Eact values of atomic oxygen calculated along various pathways were lower than 0.61 eV, confirming the high surface mobility of oxygen atoms. Interestingly, we found a clear linear correlation between the Ead of O2 on Pt147 and the Eact of subsequent O2 dissociation. The results show that Pt nanoparticles with well-developed microfacets can efficiently activate molecular oxygen and facilitate oxidation reactions.

This research aimed to find an eco-friendly way to neutralize water recovered from ready-mixed concrete by dissolving carbon dioxide in it, and to verify the potential use of such water for mixing concrete. Carbon dioxide was injected using nanobubble technology into recovered water, and the optimized conditions for dissolution were established by analyzing the carbon dioxide concentration in the water and measuring pH over time. Mortar was manufactured using this recovered water following carbon dioxide nanobubbles treatment, and measurements of compressive strength and thermogravimetric analysis (TGA) were conducted to verify the formation of calcium carbonate. 2,464 mg/L of carbon dioxide was dissolved in the recovered water, and the pH was measured to be 6.34. The compressive strength of the manufactured mortar was found to be 32.02 % stronger than mortar manufactured with normal tap water. According to the thermogravimetric analysis results, the amount of calcium hydroxide produced in the mortar manufactured with recovered water from ready-mixed concrete was 8.10 %, and the production amount of calcium carbonate was 6.49 %. This means that the amount of calcium carbonate produced was greater than that in mortar manufactured with normal tap water, as well as tap water containing nanobubble carbon dioxide. The carbon dioxide was stably dissolved in water recovered from ready-mixed concrete using nanobubbles, enabling environmentally friendly neutralization without the use of chemicals. Also, when the recovered water from ready-mixed concrete containing dissolved carbon dioxide was used for mixing concrete, it was determined that the carbonation reaction influenced the formation of calcium carbonate, which contributed to the improvement in concrete strength.