Double-layer supercapacitors ( SCs) based on carbon quantum dots (CQDs) are a novel and highly potential electrical energy storage technology. They have a high-power density (Pd) and a long span life, which are desirable for electric automobiles, however, their specific capacitance (Csp) needs to be improved. Here, we introduce an affordable and environmentally sustainable method to enhance the capacitance of Boron-Sulphur doped carbon quantum dots (B,S-CQDs) from Oloptum miliaceum (Grass) via the hydrothermal method. The findings show that heteroatom-doping might greatly enhance the Csp and energy density (Ed) when compared to undoped CQDs. As a consequence, the B,S-CQDs demonstrate a high Csp of 390 F g− 1 at 0.1 A g− 1 and 152 F g− 1 at 1.0 A g− 1, revealing excellent rate performance. Along with the electrode demonstrates superb coulombic efficiency with only 2% efficiency loss after 3000 cycles. Furthermore, the B,S-CQDs with a wide voltage range of 0.8 V yields a remarkable Ed of 48.0 Wh kg− 1 and Pd of 524 W kg− 1. These promising findings demonstrate an economical and environmentally friendly electrode material for high-performance SCs. This study offers ideas for the design and preparation of SCs electrode materials and represents a major endeavour to turn waste biomass (smilograss) into a useful electrode material.

This study presents analytical and experimental approaches to identify packing factors for polydisperse granular materials that maximize structural strength. The findings indicate that structural strength depends not only on the packing density but also on the particle-size distribution. A higher percentage of large particles correlates with greater structural strength, even for packings with identical density values. Therefore, this study proposes that the criterion for optimal packing should prioritize the maximum structural strength instead of the maximum packing density. This criterion is derived from proposed coordination numbers for polydisperse granular materials, which account for both the compaction degree and the proportion of particles of varying sizes. Physical experiments were conducted to measure the densities of packings with different particle-size distributions, and the experimental results were compared with analytical simulations using the discrete-element method. These comparisons indicate qualitative agreement between experimental and analytical data.

This study investigated the influence of alloying elements on the elastic modulus variation of titanium alloys and conducted theoretical density calculations, yielding the following conclusions. In Ti-M (M=Zr, Ag, Au, and Cu) alloys, the Md value ranges from 2.89325 to 11.1530, and the Bo value ranges from 2.30180 to 3.22978. Ti-Zr alloys are most suitable as optimal dental implant materials in terms of electronic structural stability and strength. Ti–Au and Ti–Ag primarily contribute to biocompatibility, corrosion resistance, and antibacterial performance, while offering less benefit for mechanical strengthening. Ti-Cu, while having low structural stability, exhibits excellent antibacterial functionality and is therefore worthy of consideration as a supplementary alloying element. The physical properties of ‑titanium–based Ti–M binary alloys have been examined, and future research will focus on extending the study to ternary and quaternary titanium alloy systems.

본 연구에서는 고효율 non-fullerene acceptor인 Y6의 전자구조 및 광학 물성을 정확하게 예측하기 위해 Koopmans’ theorem 기반의 optimally tuned (OT) LC-DFT와 polarizable continuum model (PCM)을 결합한 단분자 계 산 접근법을 제안한다. μ 최적화 결과, 같은 분자식 안에서 구조적 차이는 최적의 μ 값에 큰 영향을 미치지 않는 반면 기체상(gas-phase)과 응집상 환경(PCM) 간에는 뚜렷한 μ 값의 차이가 나타나며 용매 환경 효과에서 계산된 μ 값이 기 체상보다 더 작게 계산이 된다. PCM에서 최적화된 OT-LC-DFT는 고체 시료의 실험적인 이온화에너지, 전자진화도, fundamental gap과 가장 잘 일치하는 결과를 보였으며, TD-OT-LC-ωPBE로 계산된 흡수 스펙트럼은 용액 및 박막 상태 에서 관측된 근적외선 영역의 최대 흡수 피크와 적색 이동을 잘 재현하였다. 또한 HOMO/LUMO 전자 분포 분석을 통 해 μ 값에 무관하게 분자내 전하 이동(ICT) 특성이 유지됨을 확인하였다. 이러한 결과는 단분자–PCM 기반 OT-LC-DFT가 응집상 환경에서의 전자구조와 광학 물성을 신뢰성 있게 예측할 수 있는 실용적 계산 방법임을 보여준다.

Through-silicon via (TSV) filling is indispensable for three-dimensional semiconductor packaging. Conventional processes rely on PVD (physical vapor deposition) or ALD (atomic layer deposition) seed layer deposition followed by copper electroplating, but these approaches face limitations in productivity and conformality. ALD and ELD (electroless deposition) have been investigated as seed-based approaches to overcome poor step coverage, while seedless strategies have also been proposed including additive-assisted electroplating, electroless alloy layers, metallic nanowires, and conductive pastes. These methods have demonstrated void-free or seam-free fills under specific conditions, yet challenges remain in achieving uniform superconformal filling across dense arrays, suppressing copper oxidation and interfacial contamination during rinsing/drying, and guaranteeing long-term reliability under thermomechanical cycling, electromigration, and humidity bias. In parallel, hybrid bonding has emerged as an alternative to thermo-compression bonding, where TSV filling performance, CMP (chemical mechanical polishing) planarization, and interface activation are crucial to reliable bonding. An integrated research approach incorporating both seed- and seedless-based TSV filling together with hybrid bonding provides a credible pathway to reliable three-dimensional stacking for high-bandwidth memory and artificial intelligence applications.

Porous carbon derived from biomass represents pivotal electrode materials for electric double-layer capacitors (EDLCs). However, their applications are limited by the low pore utilization and low withstanding voltage (< 2.7 V), which largely hinder the energy density (Eg) of SCs. In this study, fulvic acid-derived porous carbons (FPs) were synthesized through the self-assembly and KOH activation strategy by employing fulvic acid (FA) as the precursor and cationic surfactant PDDA as the soft template. The electrostatic forces between FA and PDDA enable the structural orientation of FA, leading to the formation of stable layered liquid microcrystals. Besides, under the activation process, the decomposition of PDDA contributes to the interconnected pores in FPs. Thus, the obtained sample FP1 exhibits a high specific surface area (2593 m2 g− 1) and high mesopore ratio (48%). Moreover, low oxygen content and stable surface composition promote the withstanding voltage of FPs. In the TEABF4/ PC electrolyte, the sample FP1 is capable of a high voltage of 3.0 V, high-rate capability C10/0.05 of 76.3%, and high energy density of 39 Wh kg− 1.

High-temperature sintering is required to obtain pure and dense alumina, but it results in excessive grain growth, which eventually deteriorates the performance of the material. Technologies have been developed to lower the sintering temperature, such as the addition of a sintering aid, but these methods may cause secondary phases and still deteriorate physical properties. In this study, pure high-density alumina sintered bodies were prepared by applying an aerodynamic levitation (ADL) process without using sintering additives. Alumina that was sintered using a furnace showed a relative sintering density of 98.3 %, while alumina produced by the ADL process showed a relative density of 99.75 %. Compared to alumina prepared with the general sintering method, ADL alumina showed about a 37 % increase in hardness. ADL alumina showed a dense microstructure, attributed to instantaneous sintering at a high temperature of 2,000 °C or higher, and crystal grain growth was suppressed by rapid cooling to room temperature, resulting in ultra-high density. The ADL method is a promising manufacturing method that can improve the mechanical properties of ceramics that need to be sintered at high temperatures, and can be used to manufacture special high-performance ceramics for application in high-temperature environments.

The development of high specific surface area and mesoporous activated carbons is required to improve the electrochemical performance of EDLC. In this study, kenaf-derived activated carbons (PK-AC) were prepared for high-power-density EDLC via phosphoric acid stabilization and steam activation. The pyrolysis behavior of kenaf with respect to the phosphoric acid stabilization conditions were examined via TGA and DTG. The textural properties of PK-AC were studied with N2/ 77 K adsorption–desorption isotherms. In addition, the crystalline structure of PK-AC was observed via X-ray diffraction. The specific surface area and mesopore volume ratio of PK-AC were determined to be 1570–2400 m2/ g and 7.7–44.5%, respectively. In addition, PK-AC was observed to have a high specific surface area and mesopore volume ratio than commercial coconut-derived activated carbon (YP-50F). The specific capacitance of PK-AC was increased from 77.0–99.5 F/g (at 0.1 A/g) to 49.3–88.9 F/g (at 10.0 A/g) with activation time increased. In particular, K-P-15-H-9–10 observed an approximately 35% improvement in specific capacitance at a higher current density of 10.0 A/g compared to YP-50F. As a result, the phosphoric acid stabilization method was confirmed to be an efficient process for the preparation of high specific surface area and mesoporous biomass-derived activated carbons, and the kenaf-derived activated carbons prepared by this process have great potential for application as electrode active materials in high-power EDLC.

It is addressed that the challenges of poor cyclic stability and low conductivity in metal–organic frameworks (MOFs) hinder their application in energy storage. Here, we synthesized binary metal MOFs through a one-step hydrothermal process, subsequently calcined to produce Co–Mn/reduced graphene oxide (rGO). This approach not only carbonized the organic framework but also enhanced its electrical conductivity and stability. Our findings demonstrated that the synergistic effects of Co and Mn within the assembled electrode resulted in remarkable performance, achieving a specific capacitance of 3558.65 F g− 1 at 1 A g− 1 and a rate capability of 1000 F g− 1 at 30 A g− 1. The Co–Mn/rGO anode in the asymmetric supercapattery exhibited a broadened operating potential window of 1.5 V, delivering an energy density of 54.65 W h kg− 1 at a power density of 125 W kg− 1, and maintaining 11.375 W h kg− 1 at a high power density of 12,500 W kg− 1. Notably, the capacitance retention rate reached 99.99% after 10,000 cycles at a current density of 10 A g− 1. These results suggest that the developed Co–Mn/rGO composite represents a promising candidate for advanced energy storage systems, offering both high performance and stability.

The thermal management of high-density electronics within military shelters is a critical challenge for ensuring operational reliability, particularly under harsh field conditions involving significant solar radiation. This study presents a numerical investigation using three-dimensional Computational Fluid Dynamics (CFD) to optimize an air-cooling system for an electronics rack housed in a military shelter. Four distinct cooling configurations were analyzed and compared: (1) a baseline model relying on natural convection, (2) a fan-assisted forced convection model, (3) a direct cold air supply model using an insulated duct, and (4) a hybrid model integrating both fans and the duct. Boundary conditions were established based on the high temperature and solar radiation criteria of the MIL-STD-810G standard. To quantitatively evaluate the cooling efficiency of each system, a normalized performance index derived from a weighted sum of the average temperature and temperature standard deviation was employed. The results demonstrate that the baseline configuration leads to critical overheating, with component temperatures reaching up to 124℃. In contrast, the hybrid fan-duct system exhibited the most superior performance, effectively reducing the maximum temperature to 59℃. This is attributed to a powerful synergistic effect, where the qualitative supply of low-temperature air via the duct is combined with the quantitative distribution of flow rate throughout the system by the fans. This study elucidates an effective thermal management strategy for electronics in military shelters exposed to severe environments, identifying the integrated fan-duct system as the most robust and optimal air-cooling solution.

본 연구는 연근해 소형선박의 위치정보 데이터를 활용하여 선박 밀집도를 분석하고 향후 해상교통 혼잡도를 예측하여 선박의 안전 항해를 지원하는 데 목적이 있다. 이를 위해 선박자동식별장치(AIS) 데이터와 VBD(Visible Infrared Imaging Radiometer Suite Boat Detection) 데이터를 수집하였다. AIS는 특정 규모 이상의 선박에 설치가 의무화되어 있어, 전체 소형선박에 대한 위치정보 확보에 한계가 존재한다. 이를 보완하기 위해 위성 기반의 VBD 데이터를 융합하여, 소형선박 밀집도 분석의 정확도를 높였다. 수집된 시공간 데이터를 바탕으로 대표적인 시계열예측 모델인 LSTM(Long Short-Term Memory)을 활용하여 선박 밀집도를 예측하였으며, 이를 통해 해양사고 예방 을 위한 기초자료로 활용 가능함을 확인하였다. 본 연구의 결과는 시야 확보가 어려운 야간항해와 같이 위험 요소가 존재하는 상황에서 항해계획 수립 및 운항 결정에 실질적인 도움이 될 것으로 기대된다.

Pine wilt disease (PWD), caused by the pine wood nematode (Bursaphelenchus xylophilus), is a major threat to Pinus thunbergii forests in South Korea. Although climatic conditions are known to affect the spread of PWD, the specific influences of temperature and geography on nematode density and tree mortality remain unclear. This study assessed monthly PWN density and black pine mortality across three regions—two coastal (Geoje and Sacheon) and one inland (Jinju)—from 2021 to 2023. Nematode density and tree mortality consistently peaked in autumn across all regions. A strong positive correlation was observed between nematode density and tree mortality (r = 0.7468, p < 0.01), while temperature showed no significant correlation with either variable. These results indicate that PWD severity is more closely tied to nematode activity than to temperature alone, and that regional and seasonal variability must be considered in disease assessment. The findings highlight the need for region-specific monitoring and management strategies that prioritize high-risk periods, particularly autumn, when nematode activity and disease expression are most pronounced. This research provides essential data to support adaptive PWD control programs under changing climatic conditions.