North Korea has repeatedly provoked using unmanned aerial vehicles (UAVs), and the threat posed by UAVs continues to escalate, as evidenced by recent directives involving the use of waste-laden balloons and the development of suicide drones. North Korea’s small UAVs are difficult to detect due to their low radar cross-section (RCS) values, necessitating the efficient deployment and operation of assets for effective response. Against this backdrop, this study aims to predict the infiltration routes of enemy UAVs by considering their perspective, avoiding key facilities and obstacles, and propose deployment strategies to enable rapid detection and response during provocations. Utilizing the Markov Decision Process (MDP) based on previous studies, this research presents a model that reflects both UAV flight characteristics and regional environments. Unlike previous models that designate a single starting point, this study addresses the practical challenge of uncertainty in initial infiltration points by incorporating multiple starting points into the scenarios. By aggregating and integrating the probability maps derived from these variations into a unified map, the model predicts areas with a high likelihood of UAV infiltration over time. Furthermore, based on case studies in the capital region, this research proposes deployment strategies tailored to the specifications of currently known anti-drone integrated systems. These strategies are expected to support military decision-making by enabling the efficient operation of assets in areas with a high probability of UAV infiltration.

This study proposes a mathematical model to optimize the fighter aircraft-weapon combinations for the Republic of Korea Air Force. With the recent emergence of the population cliff issue due to declining birth rates in Korea, there is an urgent need for efficient weapon system operations in light of decreasing military personnel. This study aims to enhance operational environments and mission efficiency within the military. The objective is to reduce the workload of pilots and maintenance personnel by operating an optimal number of weapons instead of deploying all possible armaments for each aircraft type. To achieve this, various factors for optimizing the fighter-weapon combinations were identified and quantified. A model was then constructed using goal programming, with the objective functions based on the compatibility, Circular Error Probable (CEP), and fire range of the weapons, along with the planned wartime mission-specific weapon ratios for each aircraft type. Experimental analysis of the proposed model indicated a significant increase in mission performance efficiency compared to the existing system in both operational and maintenance aspects. It is hoped that this model will be applied in military settings.

This study presents an optimization model for the Tactical Information Communication Network (TICN), which is crucial for military operations, focusing on the efficient deployment of communication nodes to create a rapid and robust network while minimizing both distances and the number of nodes required. By integrating mixed integer programming (MIP) with minimum spanning tree (MST) and Steiner Tree algorithms, the model ensures that nodes are connected through the shortest, most efficient routes. Simulations demonstrate the model’s ability to form cohesive networks under constrained resources and time, reducing transmission distances and maintaining network stability. Case studies in a grid environment confirm the system's efficiency, with the model able to redeploy nodes if damaged to preserve network integrity. By utilizing both high- and low-capacity transmission systems, the model ensures reliable communication in challenging terrains like Korea’s mountainous landscape. The findings have critical implications for military communication strategies, especially for multi-domain operations involving air, land, and sea forces, and support decision-making for rapid and efficient deployment of communication networks in unpredictable conditions.

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.

A substantial quantity of discarded tires has inflicted harm on the environment. Microwave pyrolysis of discarded tires emerges as an efficient and environmentally friendly method for their recycling. This research innovatively utilizes the characteristics of microwave rapid and selective heating to pyrolyze waste tires into porous graphene under the catalysis of KOH etching. Moreover, this study comprehensively investigates the dielectric characteristics and heating behavior of waste tires and different proportions of waste tire–KOH mixtures. It validates the preparation of graphene through KOH-catalyzed microwave pyrolysis of waste tires, tracking morphological and structural changes under varying temperature conditions. The results indicate that optimal dielectric performance of the material is achieved at an apparent density of 0.68 g/cm3 at room temperature. As the temperature increases, the dielectric constant gradually rises, particularly reaching a notable increase around 700 °C, and then stabilizes around 750 °C. Additionally, the study investigates the penetration depth and reflection loss of mixtures with different proportions, revealing the waste tire–KOH mass ratio of 1:2 demonstrates favorable dielectric properties. This research highlights the impressive microwave responsiveness of the waste tire–KOH mixture, Upon the addition of KOH, the mixed material exhibits an augmented dielectric constant and relative dielectric constant, supporting the viability of KOH-catalyzed microwave pyrolysis for producing porous graphene from waste tires. This method is expected to provide a new method for the valuable reuse of waste tires and a technology for large-scale, efficient and environmentally friendly production of graphene.

Carbon quantum dots (CQDs) are novel nanocarbon materials and widely used nanoparticles. They have gradually gained popularity in various fields due to their abundance, inexpensive cost, small size, ease of engineering, and distinct properties. To determine the antibacterial activity of metal-doped CQDs (metal-CQDs) containing Fe, Zn, Mn, Ni, and Co, we chose Staphylococcus aureus as a representative Gram-positive strain and Escherichia coli as a representative Gram-negative bacterial strain. Paper disc diffusion tests were conducted for the qualitative results, and a cell growth curve was drawn for quantitative results. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and IC50 were measured from cell growth curves. As a result, all of the metal-CQDs showed toxicity against both Gram-positive and Gram-negative bacteria. Furthermore, Gram-negative bacteria was vulnerable to metal-CQDs than Gram-positive bacteria. The toxicity differed concerning the type of metal-CQDs; Mn-CQDs exhibited the highest efficacy. Hence, this study suggested that CQDs can be used as new nanoparticles for antibiotics.

In this study, carbon coating was carried out by physical vapor deposition (PVD) on SiOx surfaces to investigate the effect of the deposited carbon layer on the performance of lithium-ion batteries as a function of the asphaltene content of petroleum residues. The petroleum residue was separated into asphaltene-free petroleum residue (ASF) and asphaltene-based petroleum residue (AS) containing 12.54% asphaltene by a solvent extraction method, and the components were analyzed. The deposited carbon coating layer became thinner, with the thickness decreasing from 15.4 to 8.1 nm, as the asphaltene content of the petroleum residue increased, and a highly crystalline layer was obtained. In particular, the SiOx electrode carbon-coated with AS exhibited excellent cycling performance with an initial efficiency of 85.5% and a capacity retention rate of 94.1% after 100 cycles at a current density of 1.0 C. This is because the carbon layer with enhanced crystallinity had sufficient thickness to alleviate the volume expansion of SiOx, resulting in stable SEI layer formation and enhanced structural stability. In addition, the SiOx electrode exhibited the lowest resistance with a low impedance of 23.35 Ω, attributed to the crystalline carbon layer that enhanced electrical conductivity and the mobility of Li ions. This study demonstrated that increasing the asphaltene content of petroleum residues is the simplest strategy for preparing SiOx@C anode materials with thin, crystalline carbon layers and excellent electrochemical performance with high efficiency and high rate performance.

The economical manufacturing of high-quality graphene has been a significant challenge in its large-scale application. Previously, we used molten Sn and Cu as the heat-transfer agent to produce multilayer graphene on the surface of gas bubbles in a bubble column. However, element Sn and Cu have poor catalytic activity toward methane pyrolysis. To further improve the yield of graphene, we have added active Ni into Sn to construct a Sn–Ni alloy in this work. The results show that Sn–Ni alloy is much more active for methane pyrolysis, and thus more graphene is obtained. However, the graphene product is more defective and thicker because of the faster growth rate. By using 300 ml molten Sn–Ni alloy (70 mm height) and 500 sccm source gas ( CH4:Ar = 1:9), this approach produces graphene with a rate of 0.61 g/hr and a conversion rate of methane to carbon of 37.9% at 1250 ℃ and ambient pressure. The resulting graphene has an average atom layer number of 22, a crumpled structure and good electrical conductivity.

In this work, the depth of the interphase in graphene polymer systems is determined by the properties of graphene and interfacial parameters. Furthermore, the actual volume fraction and percolation onset of the nanosheets are characterized by the actual inverse aspect ratio, interphase depth, and tunneling distance. In addition, the dimensions of graphene, along with interfacial/interphase properties and tunneling characteristics, are utilized to develop the power-law equation for the conductivity of graphene-filled composites. Using the derived equations, the interphase depth, percolation onset, and nanocomposite conductivity are graphed against various ranges of the aforementioned factors. Moreover, numerous experimental data points for percolation onset and conductivity are presented to validate the equations. The optimal levels for interphase depth, percolation onset, and conductivity are achieved through high interfacial conductivity and large graphene nanosheets. In addition, increased nanocomposite conductivity can be attained with thinner nanosheets, a larger tunneling distance, and a thicker interphase. The calculations highlight the considerable impacts of interfacial/interphase factors and tunneling distance on the percolation onset. The highest nanocomposite conductivity of 0.008 S/m is acquired by the highest interfacial conduction of 900 S/m and graphene length (D) of 5 μm, while an insulated sample is observed at D < 1.2 μm. Therefore, higher interfacial conduction and larger nanosheets cause the higher nanocomposite conductivity, but the short nanosheets cannot promote the conductivity.

For metal-free carbocatalysts, heteroatom doping and hierarchically porous structure are the significant factors to improve their catalytic performances. Herein, N-, P-co-doped hierarchically porous carbon fiber (NPC–2–800) was prepared by pyrolyzing bamboo pulp in combination with ( NH4)2HPO4 and activator K2CO3. It was found that ( NH4)2HPO4 not only provides N and P atoms, but also significantly affect the morphology and pore structure of the porous carbon. An appropriate dosage of ( NH4)2HPO4 facilitates the formation of hierarchically porous carbon fiber in NPC-2–800. Whereas, the carbon fragments with only micropores were obtained in absence of ( NH4)2HPO4. The hierarchical porosity and the co-doping of N and P atoms in the NPC-2–800 contribute to its outstanding catalytic performances in the 4-Nitrophenol (4-NP) reduction assisted by NaBH4. The NPC-2–800 exhibits an attractive turnover frequency (TOF) value of 4.29 × 10– 4 mmol mg− 1 min− 1, a low activation energy (Ea) of 24.76 kJ/mol, and an acceptable recyclability for 7 cycles without obvious decrease in activity. Kinetics analyses suggest that the 4-NP reduction proceeds through the Langmuir–Hinshelwood model. In addition, the NPC-2–800 can also efficiently catalyze the 2-NP and 3-NP reduction. Moreover, in the real water body, the NPC-2–800 also showed superior catalytic activity to catalyze 4-NP reduction. This study provides an efficient catalyst for pollutant conversion and elimination as well as guidelines for designing versatile carbon-based catalysts.

This study delves into the potential application of whisker carbon nanotube (w-CNT) in terms of electrical heating performance, with a particular emphasis on its significance in high-efficiency electrothermal conversion applications. Meanwhile, a comparative study was conducted on traditional carbon nanotubes (T1 and T3) with different aspect ratios. A uniform and dense carbon nanotube paper (BP) was prepared using a vacuum filtration method, including single-layer (T1, T3 and w-CNT BP), double-layer gradient composite (T1/T3-g, w-CNT/T3-g), and mixed composite (T1/T3-m and w-CNT/T3-m). The thickness of each type of BP is approximately 100 μm. The results demonstrated that electrical conductivity and electrical heating performance of single-layer BPs follow the order of T1 > T3 > w-CNT. While, mixed composite BPs are superior to double-layer gradient composite BPs in electrical conductivity and thermal performance. Notably, w-CNT/T3-m BP exhibits excellent electrothermal performance. Under an applied voltage of 5 V, the surface temperature of w-CNT/T3-m BP reaches 190 ℃. When the voltage is increased to 6 V, the surface temperature rises by 150℃ within 10 s, reaching a steady-state temperature of 318 ℃. This excellent electrothermal performance can be attributed to the introduction of w-CNT, which has a perfect and defect free structure according to Raman analysis. In-depth analysis using X-ray diffraction (XRD) indicated a more complete and higher degree of crystallinity in the w-CNT structure. In summary, this study not only provides experimental and theoretical basis for the application of high-performance electrothermal materials based on carbon nanotubes, but also foreshadows their broad application prospects in the field of macroscopic materials.

In this study, ester co-solvents and fluoroethylene carbonate (FEC) were used as low-temperature electrolyte additives to improve the formation of the solid electrolyte interface (SEI) on graphite anodes in lithium-ion batteries (LIBs). Four ester co-solvents, namely methyl acetate (MA), ethyl acetate, methyl propionate, and ethyl propionate, were mixed with 1.0 M LiPF6 ethylene carbonate:diethyl carbonate:dimethyl carbonate (1:1:1 by vol%) as the base electrolyte (BE). Different concentrations were used to compare the electrochemical performance of the LiCoO2/ graphite full cells. Among various ester co-solvents, the cell employing BE mixed with 30 vol% MA (BE/MA30) achieved the highest discharge capacity at − 20 °C. In contrast, mixing esters with low-molecular-weight degraded the cell performance owing to the unstable SEI formation on the graphite anodes. Therefore, FEC was added to BE/MA30 (BE/MA30-FEC5) to form a stable SEI layer on the graphite anode surface. The LiCoO2/ graphite cell using BE/MA30-FEC5 exhibited an excellent capacity of 127.3 mAh g− 1 at − 20 °C with a capacity retention of 80.6% after 100 cycles owing to the synergistic effect of MA and formation of a stable and uniform inorganic SEI layer by FEC decomposition reaction. The low-temperature electrolyte designed in this study may provide new guidelines for resolving low-temperature issues related to LIBs, graphite anodes, and SEI layers.

With the development of photocatalytic hydrogen production technology, the effective transport of photogenerated carrier electrons is still one of the main factors affecting the performance of photocatalytic hydrogen evolution. In this work, graphdiyne was prepared by ball milling method. The CoMo-MOF with polyhedral structure was introduced into graphdiyne to construct S-scheme heterojunction to promote the efficient transfer of photogenerated carriers and enhanced hydrogen evolution activity. Graphdiyne is a new carbon material with adjustable band gap, which is synthesized from the hybrid of sp and sp2, and has excellent electrical conductivity. CoMo-MOF is a polyhedral structure that can provide more active sites and promote photocatalytic hydrogen evolution. The weak point of poor conductivity in CoMo-MOF has been successfully improved by combining CoMo-MOF with graphdiyne, and the migration rate of photogenerated carriers has been accelerated. The hydrogen evolution property of graphdiyne/CoMo-MOF is 300 μmol, which is 19.61 times that of graphdiyne and 9.03 times that of CoMo-MOF. Therefore, the construction of S-scheme heterojunction provides a transport channel for electron transfer and improves the efficiency of photogenerated carrier separation. This work provides a new train of thought of design to introduce MOFs materials into carbon materials for photocatalytic hydrogen evolution.

Various transition metal oxides are deposited on the surface of materials such as stainless steel, which is used in the coolant systems of nuclear power plants. The task of removing harmful radionuclides can be solved through the dissolution reaction of the deposited corrosion oxide layer. In this study, for the first time, the reaction thermodynamics of the hydrazine-based reductive metal ion decontamination (HyBRID) reaction developed by the Korea Atomic Energy Research Institute were studied considering the formation of a strong ion − ligand chemical bond complex between Cu ions and hydrazine. When considering complex formation, we found that it had a significant impact on the thermodynamic decontamination reactions of magnetite, nickel ferrite, and chromite. The reactions were proven to be much more thermodynamically favorable than the reaction energies reported thus far, which did not consider complex formation. We demonstrated that not only the thermodynamic energy but also the structures of the HyBRID reaction products can be significantly changed, depending on complex formation considerations.

To improve the lithium-ion battery performance and stability, a conducting polymer, which can simultaneously serve as both a conductive additive and a binder, is introduced into the anode. Water-soluble polyaniline:polystyrene sulfonate (PANI:PSS) can be successfully prepared through chemical oxidative polymerization, and their chemical/mechanical properties are adjusted by varying the molecular weight of PSS. As a conductive additive, the PANI with a conjugated double bond structure is introduced between active materials or between the active material and the current collector to provide fast and short electrical pathways. As a binder, the PSS prevents short circuits through strong π‒π stacking interaction with active material, and it exhibits superior adhesion to the current collector, thereby ensuring the maintenance of stable mechanical properties, even under high-speed charging/discharging conditions. Based on the synergistic effect of the intrinsic properties of PANI and PSS, it is confirmed that the anode with PANI:PSS introduced as a binder has about 1.8 times higher bonding strength (0.4 kgf/20 mm) compared to conventional binders. Moreover, since active materials can be additionally added in place of the generally added conductive additives, the total cell capacity increased by about 12.0%, and improved stability is shown with a capacity retention rate of 99.3% even after 200 cycles at a current rate of 0.2 C.

With the emergence of the new energy field, the demand for high-performance lithium-ion batteries (LIBs) and green energy storage devices is growing with each passing day. Carbon nanotubes (CNTs) exhibit tremendous potential in application due to superior electrical and mechanical properties, and the excellent lithium insertion properties make it possible to be LIBs anode materials. Based on the lithium insertion mechanism of CNTs, this paper systematically and categorically reviewed the design strategies of CNTs-based composites as LIBs anode materials, and summarized in detail the enhancement effect of CNTs fillers on various anode materials. More importantly, the superiorities and limitations of various anode materials for LIBs were evaluated. Finally, the research direction and current challenges of the industrial application of CNTs in LIBs were prospected.

Colorectal cancer (CRC) poses a significant global public health challenge, accounting for 10% of newly diagnosed cancer cases and causing 9.4% of cancer-related deaths. Conventional treatment methods like surgery, chemotherapy, and radiation have shown limited success despite the increasing incidence of CRC. Thus, there is an urgent need for innovative therapeutic approaches. Researchers are continually working on developing novel technologies, notably focused on the creation of safe and effective cancer nanomedicines, in their continuous effort to advance cancer treatment. Nanoparticles exist at the nanoscale. Nanoparticles at the nanoscale have distinctive properties that leverage the metabolic disparities between cancerous and normal cells. This property allows them to selectively induce substantial cytotoxicity in cancer cells while minimizing damage to healthy tissue. Carbon nanomaterials (CNMs), including graphene oxide (GO), carbon nanotubes (CNTs), and nanodiamonds (NDs), have undergone extensive investigation due to their biocompatibility, surface-to-volume ratio, thermal conductivity, rigid structural properties, and ability for post-chemical modifications. Notably, GO has emerged as a promising two-dimensional (2D) material for cancer treatment. Several groundbreaking nanoparticle-based therapies, predominantly utilizing GO, are currently undergoing clinical trials, with some already gaining regulatory clearance.

This study investigates how adding cognitive stimulation to exercise impacts overall outcomes. Cognitive stimulation involves engaging mental processes like attention, memory, and problem-solving while being physically active. The intervention integrates activities that challenge mental functions into exercise routines. Existing research suggests that such interventions can improve various aspects of exercise performance, such as adherence, enjoyment, and perceived effort. Additionally, they may also lead to enhanced cognitive function and mental well-being, hinting at potential combined benefits of mental and physical activity. Understanding the effects of cognitive stimulation on exercise can help in developing more effective strategies for promoting both physical and cognitive health. In summary, physical exercise emerges as a powerful tool for enhancing cognitive stimulation and mental well-being. By making regular physical activity a habit, individuals can reap cognitive benefits alongside physical ones, underlining the importance of including exercise in daily routines for optimal cognitive function and overall health.

This study is a descriptive research study to confirmed the mediating effect of career adaptability in the relationship between growth mindset and career preparation behavior in order to improve the career preparation behavior of nursing students. The subjects of the study were second, third, and fourth year students attending nursing departments at two universities located in cities G and M.. The data were collected from May to June 2024. Analysis of the collected data was performed using descriptive statistics, Pearson correlation coefficient, and Baron-Kenny regression analysis. As a result of the study, first, growth mindset showed a positive effect(β=.397, p<.001) on career adaptability. Second, growth mindset showed a positive effect(β=.337, p<.001) on career preparation behavior. Third, growth mindset (β=138, p<.001) and career adaptability (β=.502, p<.001) each had a statistically significant impact on career preparation behavior. As a result, it was confirmed that career adaptability has a partial mediating effect between growth mindset and career preparation behavior. Therefore, it can be seen that the higher the growth mindset, the more career adaptability is promoted, which in turn promotes career preparation behavior. Based on these research results, in order to improve the career preparation behavior of nursing students, growth mindset and career adaptability should be promoted in the field of nursing education.

This study aims to develop a detailed sizing system for lower body clothing for elderly obese women, using data from the 8th Korean Anthropometric Survey. The research targets 296 elderly women aged 60 to 85, selected from 805 participants in total, who meet the following criteria: Rohrer Index of 1.6 or above, Body Mass Index of 25 or higher, and Waist-Hip Ratio of 0.85 or greater. Elderly women with abdominal obesity exhibit shorter lower body proportions and greater fat accumulation in the torso, around the chest and waist. The findings show that women in their 60s have the highest level of obesity, while waist width and thickness are greatest in women in their 70s, suggesting that abdominal obesity increases with age. According to the KS standards, the main measurement categories were divided into 5cm increments for height, while waist and hip girth were categorized into 5cm and 3cm, respectively, to analyze the distribution of sections. Clothing size standards for lower garments that require a precise fit, such as skirts and formal pants, are presented in 13 sizes, corresponding to a waist girth range of 85–100cm and a hip girth range of 88–97cm. Detailed measurements are categorized into primary and reference areas. Additionally, sizes were presented differently based on whether a precise fit was necessary. For items that did not require a precise fit, ranges were indicated with letters, or ranges were indicated with measurements. Detailed sizes were categorized into primary and reference areas.