The effects of La3+ substitution for Sr2+-site on the crystal structure and the dielectric properties of (Ba0.7Sr0.3-3x/2Lax) (Ti0.9Zr0.1)O3 (BSLTZ) (0.005 ≤ x ≤ 0.02) ceramics were investigated. The structural characteristics of the BSLTZ ceramics were quantitatively evaluated using the Rietveld refinement method from X-ray diffraction (XRD) data. For the specimens sintered at 1,550 °C for 6 h, a single phase with a perovskite structure and homogeneous microstructure were observed for the entire range of compositions. With increasing La3+ substitution (x), the unit cell volume decreased because the ionic size of La3+ (1.36 Å) ions is smaller than that of Sr2+ (1.44 Å) ions. With increasing La3+ substitution (x), the tetragonal phase fraction increased due to the A-site cation size mismatch effect. Dielectric constant (εr) increased with the La3+ substitution (x) due to the increase in tetragonality (c/a) and the average B-site bond valence of the ABO3 perovskite. The BSLTZ ceramics showed a higher dielectric loss due to the smaller grain size than that of (Ba0.7Sr0.3)(Ti0.9Zr0.1)O3 ceramics. BSLTZ (x = 0.02) ceramics met the X7R specification proposed by the Electronic Industries Association (EIA).

In order to develop catechin patches for skin regeneration at wound sites, patches with varying concentrations of catechin and chitosan were manufactured. An optimal composition ratio was determined by adjusting the drug release rate and amount, to maximize efficiency. The catechin used in this study was extracted from green tea leaves using a solvent/ultrasonication method, and its characteristics were confirmed through Fourier transform-infrared spectroscopy (FT-IR) and high-performance liquid chromatography (HPLC) analyses. Patches were prepared with different concentrations of catechin and chitosan, and various properties were analyzed using techniques such as FT-IR, water contact angle analysis, and UV-Vis spectroscopy. It was observed that as the chitosan concentration increased, the release of catechin slowed down or almost ceased. A patch manufactured with 1.5 mg/cm2 of catechin at a 1 % chitosan concentration exhibited a high initial release rate over 24 h and demonstrated cellular biocompatibility. Consequently, these patches, with tailored release characteristics based on the concentrations of chitosan and catechin, hold promise for use as drug delivery systems in wound healing applications.

Single-atom Pd clusters anchored on t-BaTiO3 material was synthesized using hydrothermal and ultrasonic methods for the effective piezoelectric catalytic degradation of pollutants using vibration energy. XRD patterns of BaTiO3 loaded with monoatomic Pd were obtained before and after calcining, and showed typical cubic-phase BTO. TEM and HAADF-STEM images indicated single-atom Pd clusters were successfully introduced into the BaTiO3. The piezoelectric current density of the prepared Pd-BaTiO3 binary composite was significantly higher than that of the pristine BaTiO3. Under mechanical vibration, the nanomaterial exhibited a tetracycline decomposition rate of ~95 % within 7 h, which is much higher than the degradation rate of 56.7 % observed with pure BaTiO3. Many of the piezo-induced electrons escaped to the Pd-doped BaTiO3 interface because of Pd’s excellent conductivity. Single-atom Pd clusters help promote the separation of the piezo-induced electrons, thereby achieving synergistic catalysis. This work demonstrates the feasibility of combining ultrasonic technology with the piezoelectric effect and provides a promising strategy for the development of ultrasonic and piezoelectric materials.

Changes in the microstructure and mechanical properties of as-roll-bonded AA6061/AA5052/AA1050 threelayered sheet with increasing annealing temperature were investigated in detail. The commercial AA6061, AA5052 and AA1050 sheets with 2 mm thickness were roll-bonded by multi-pass rolling at ambient temperature. The roll-bonded Al sheets were then annealed for 1 h at various temperatures from 200 to 400 °C. The specimens annealed up to 250 °C showed a typical deformation structure where the grains are elongated in the rolling direction in all regions. However, after annealing at 300 °C, while AA6061 and AA1050 regions still retained the deformation structure, but AA5052 region changed into complete recrystallization. For all the annealed materials, the fraction of high angle grain boundaries was lower than that of low angle grain boundaries. In addition, while the rolling texture of the {110}<112> and {123}<634> components strongly developed in the AA6061 and AA1050 regions, in the AA5052 region the recrystallization texture of the {100}<001> component developed. After annealing at 350 °C the recrystallization texture developed in all regions. The as-rolled material exhibited a relatively high tensile strength of 282 MPa and elongation of 18 %. However, the tensile strength decreased and the elongation increased gradually with the increase in annealing temperature. The changes in mechanical properties with increasing annealing temperature were compared with those of other three-layered Al sheets fabricated in previous studies.

Purpose: This study aims to analyze the domestic studies on spiritual health to confirm research trends and present future direction. Methods: This study adopts the scoping review method, which comprises six stages: 1) identify the initial research question; 2) identify the relevant studies; 3) study selection; 4) “charting” the data; 5) collate, summarize, and report the results; and 6) optional consultation. An analysis of 372 research works between 1980 and 2022 was carried out. Results: Among the 372 studies reviewed, 218 were on nursing. The most frequently used study design was survey-correlational. The majority of study participants were patients and nursing students. The main research topic was spiritual well-being. In interventional research, the most frequently used program was spiritual care and spiritual care education. In the survey-correlational study, the variable of spiritual health had a positive relation with quality of life and mental health and a negative relation with depression and anxiety. The main instrument used for measuring variables was Paloutzian and Ellison’s spiritual well-being scale. Conclusion: The domestic research about spiritual health needs to utilize a variety of approaches, including tool development studies suitable for the Korean people, qualitative studies, systemic reviews and meta-analyses on spiritual health promotion program, typifying variables related to spiritual health.

Purpose: This study describes and seeks to understand the experiences of Korean nurses at a specialty hospital in the United Arab Emirates. Methods: Data were collected from September 12 to October 12, 2023, through in-depth interviews with 10 Korean nurses who had worked at a specialty hospital in the Middle East for more than five years. Recorded interviews were transcribed verbatim. The data were analyzed using the qualitative thematic analysis method suggested by Braun and Clarke. Results: The analysis identified four themes and 10 sub-themes. The themes are as follows: “Job insecurity and a rapid change of employment conditions”, “Stress of a dual organizational culture”, “Confusion due to cultural differences”, and “Advantages and rewards of working abroad”. Conclusion: Korean hospitals expanding into the Middle East through international medical projects can utilize the information gleaned from Korean nurses' experiences at the United Arab Emirates Specialty Hospital.

Purpose: This study utilizes a phenomenological research method to understand the nature of role adaptation experience of PA nurses. Methods: This was a qualitative study that applied Colaizzi’s phenomenological research method to understand the nature of role adaptation experience of PA nurses. The study participants were thirteen PA nurses (three men and ten women) with over five years of experience. For data collection, individual in-depth interviews were conducted, each about 50 to 90 minutes long. Individual interviews were conducted once or twice. Colaizzi’s method was used to analyze data. Results: The result of this study had 11 clusters of themes and 4 major themes were derived from the analysis: “parallel lines of conflict,”“anxiety about unclear future,”“disorganization of identity,”and “my own way to learn about myself.”These four major themes are structured chronologically to the extent possible but are not mechanically segmented based on time. Conclusion: This study recognizes the seriousness of PA nurses’problems in the absence of research on PA nurses’role adaptation experience and recommends that appropriate research is necessary. Standardized work guidelines and positive awareness of the role of PA nurses are necessary and are supported by PA nurses to establish their position as professionals.

Purpose: This study aimed to investigate the perception of visiting hospice services to end-of-life patients at home. Methods: Individual in-depth interviews and qualitative content analysis were used for data collection and analysis, respectively. The study’s participants were 15 end-of-life patients receiving visiting hospice services at home. Results: Four themes emerged from nine subthemes, which were categorized from 26 condensed meaning units by interpreting underlying meanings. The four themes were “service with value started by chance”, “service that fills the care gap”, “service that the vulnerable group can rely on”, and “service that is insufficient to medical support”. Conclusion: Based on these results, it is suggested that policy support is needed to develop and apply a community-based hospice service model that connects hospitals and homes.

Purpose: This study aims to not only understand the meaning and essence of patients’experiences visiting the Raphael Nanum Homeless Clinic but also explore what kind of healthcare programs they would like to have in the future by appraising patients’experiences in depth. Methods: This study employed a qualitative content analysis method. The data were collected from June 11, 2023, to June 25, 2023. A total of 17 patients who could provide detailed experiences of their visit to the Raphael Nanum homeless clinic participated in this study. We conducted a focus group interview with 6 patients and in-depth one-on-one interviews with the remaining 11 patients. Results: The qualitative content analysis result revealed five themes: “visiting a free clinic for various paths,” “positive experiences at the free clinic,” “negative experiences at the free clinic,” “dissatisfaction with the clinic site,” and “anticipation for the future of the free clinic.” Conclusion: To ensure the right to health and survival of marginalized populations in the future, it is necessary to establish comprehensive healthcare support measures, which include enhancing the facilities of the free clinic and expanding the range of available medical specialties.

Purpose: To determine whether artificial -intelligence quarantine robots can positively contribute to environmental management in medical institutions. We conducted in-depth interviews to understand the experiences of hospitalized patients receiving environmental management from such robots. Methods: Data were collected during March 20~May 20, 2023. individual in-depth interviews were conducted with 15 hospitalized patients, who could provide specific details of their experience of receiving environmental management from a quarantine robot. Results: Qualitative content analysis identified four themes, including “First encounter with an amazing and new quarantine robot,” “Efficiently performs non-face-to-face quarantine work in hospitals,” “Problems with quarantine robots,” and “Recommendations for improving the functionality of quarantine robots in medical institutions so quarantine robots and humans can coexist.” Conclusion: Currently, quarantine robots have limited functionality, and additional research is needed to identify various other functions in consideration of future infectious disease situations and the level of quarantine appropriate in a hospital.

Purpose: This study aimed to explore the practical experience of nursing graduates through a clinical practicum alternative program during the COVID-19 pandemic. Methods: Participants in this study comprised sixteen students who had gone through clinical field practice and clinical alternative programs during 4 semesters at nursing college. Data were collected through individual in-depth interviews and analyzed via the phenomenological research method developed by Colaizzi. Results: From the meaningful statements offered by the participants, six theme clusters emerged: (a) interest in new experiences, (b) practice that doesn’t feel like practice, (c) limits on yourself, (d) ambivalence about alternative programs, (e) longing for vivid clinical settings, and (f) choice in an unavoidable situation. Conclusion: This study provides a profound understanding of the practical experiences of nursing students during the COVID-19 pandemic situation about the clinical practicum alternative program. Based on this study, it is necessary to determine how students who have participated in the implementation of the clinical practice alternative program are adapting to the actual field as nurses. It is also necessary to develop various programs that reflect the needs of students and utilize technologies such as virtual reality, augmented reality, and metaverse along with current teaching methods.

Purpose: The purposes of this study was to identify the nurses' experiences of prolonged mask wearing in the context of COVID-19. Methods: This study was a qualitative study that used the content analysis method. Data were collected using focus group interviews with 18 nurses at a tertiary general hospital from April 13 to 27, 2023. Results: Five themes and 15 sub-themes emerged through qualitative content analysis. The themes included: “Mandatory or optional experience of wearing a mask unrelated to COVID-19”, “Mandatory KF94 masks during the COVID-19 pandemic”, “Multifaceted changes in life due to mandatory mask wearing”, “Unexpected benefits of wearing a mask”, “Difficulties with wearing masks continue even after the COVID-19 pandemic”. Conclusion: This study confirmed the discomfort and difficulties of prolonged mask wearing among nurses in the context of COVID-19. Our findings suggest that there is a need for organizational and national support for nurses who are required to continue wearing masks after the COVID-19 pandemic.

In this study, we synthesized pH-controlled resorcinol-formaldehyde (RF) gels through the polymerization of two starting materials: resorcinol and formaldehyde. The prepared RF gels were dried using an acetone substitution method, and they were subsequently carbonized under nitrogen atmosphere to obtain carbon xerogels (CX_Y) prepared at different pH (Y). The carbon xerogels were utilized as active materials for coin-type organic supercapacitor electrodes to investigate the influence of pH on the electrochemical properties of the carbon xerogels. The carbon xerogels prepared at lower pH (CX_9.5 and CX_10) exhibited sufficient particle growth, with a three-dimensional network of particles during the RF gel formation, resulting in the development of abundant mesopores. Conversely, the carbon xerogels prepared at higher pH (CX_11 and CX_12) retained densely packed structures of small particles, leading to pore collapse and low specific surface areas. Consequently, CX_9.5 and CX_10 showed high specific surface areas, and provided ample adsorption sites for the formation of electric double layers with electrolyte ions. Moreover, the three-dimensional particle network in CX_9.5 and CX_10 significantly enhanced electrical conductivity. The presence of well-developed mesopores in these materials further facilitated the effective transport of electrolyte ions, contributing to their superior performance as organic supercapacitor electrodes. This study confirmed that pH-controlled carbon xerogels are one of the promising active materials for organic supercapacitor electrodes. Furthermore, we concluded that pH during RF gel formation is a crucial factor determining the electrode performance of the carbon xerogels, highlighting the need for precise pH control to obtain high-performance carbon xerogel electrodes.

High-strength low-alloy steel is one of the widely used materials in onshore and offshore plant engineering. We investigated the alloying effect of solute atoms in α-Fe based alloy using ab initio calculations. Empirical equations were used to establish the effect of alloying on the Vicker’s hardness, screw energy coefficient, and edge dislocation energy coefficient of the steel. Screw and edge energy coefficients were improved by the addition of V and Cr solute atoms. In addition, the addition of trace quantities of V, Cr, and Mn enhanced abrasion resistance. Solute atoms and contents with excellent mechanical properties were selected and their thermal conductivity and thermal expansion behavior were investigated. The addition of Cr atom is expected to form alloys with low thermal conductivity and thermal expansion coefficient. This study provides a better understanding of the state-of-the-art research in low-alloy steel and can be used to guide researchers to explore and develop α-Fe based alloys with improved properties, that can be fabricated in smart and cost-effective manners.

Infrared radiation (IR) refers to the region of the electromagnetic radiation spectrum where wavelengths range from about 700 nm to 1 mm. Any object with a temperature above absolute zero (0 K) radiates in the infrared region, and a material that transmits radiant energy in the range of 0.74 to 1.4 um is referred to as a near-infrared optical material. Germanatebased glass is attracting attention as a glass material for infrared optical lenses because of its simple manufacturing process. With the recent development of the glass molding press (GMP) process, thermal imaging cameras using oxide-based infrared lenses can be easily mass-produced, expanding their uses. To improve the mechanical and optical properties of commercial materials consisting of ternary systems, germanate-based heavy metal oxide glasses were prepared using a melt-cooling method. The fabricated samples were evaluated for thermal, structural, and optical properties using DSC, XRD, and XRF, respectively. To derive a composition with high glass stability for lens applications, ZnO and Sb2O3 were substituted at 0, 1, 2, 3, and 4 mol%. The glass with 1 mol% added Sb2O3 was confirmed to have the optimal conditions, with an optical transmittance of 80 % or more, a glass transition temperature of 660 °C, a refractive index of 1.810, and a Vickers hardness of 558. The possibility of its application as an alternative infrared lens material to existing commercial materials capable of GMP processing was confirmed.

This study used optical and scanning electron microscopy to analyze the surface oxidation phenomenon that accompanies a γ'-precipitate free zone in a directional solidified CM247LC high temperature creep specimen. Surface oxidation occurs on nickel-based superalloy gas turbine blades due to high temperature during use. Among the superalloy components, Al and Cr are greatly affected by diffusion and movement, and Al is a major component of the surface oxidation products. This out-diffusion of Al was accompanied by γ' (Ni3Al) deficiency in the matrix, and formed a γ'-precipitate free zone at the boundary of the surface oxide layer. Among the components of CM247LC, Cr and Al related to surface oxidation consist of 8 % and 5.6 %, respectively. When Al, the main component of the γ' precipitation phase, diffused out to the surface, a high content of Cr was observed in these PFZs. This is because the PFZ is made of a high Cr γ phase. Surface oxidation of DS CM247LC was observed in high temperature creep specimens, and γ'-rafting occurred due to stress applied to the creep specimens. However, the stress states applied to the grip and gauge length of the creep specimen were different, and accordingly, different γ'-rafting patterns were observed. Such surface oxidation and PFZ and γ'-rafting are shown to affect CM247LC creep lifetime. Mapping the microstructure and composition of major components such as Al and Cr and their role in surface oxidation, revealed in this study, will be utilized in the development of alloys to improve creep life.

Tb3+-doped CaNb2O6 (CaNb2O6:Tb3+) thin films were deposited on quartz substrates at a growth temperature of 300 °C using radio-frequency magnetron sputtering. The deposited thin films were annealed at several annealing temperatures for 20 min and characterized for their structural, morphological, and luminescent properties. The experimental results showed that the annealing temperature had a significant effect on the properties of the CaNb2O6:Tb3+ thin films. The crystalline structure of the as-grown CaNb2O6:Tb3+ thin films transformed from amorphous to crystalline after annealing at temperatures greater than or equal to 700 °C. The emission spectra of the thin films under excitation at 251 nm exhibited a dominant emission band at 546 nm arising from the 5D4 → 7F5 magnetic dipole transition of Tb3+ and three weak emission bands at 489, 586, and 620 nm, respectively. The intensity of the 5D4 → 7F5 (546 nm) magnetic dipole transition was greater than that of the 5D4 → 7F6 (489 nm) electrical dipole transition, indicating that the Tb3+ ions in the host crystal were located at sites with inversion symmetry. The average transmittance at wavelengths of 370~1,100 nm decreased from 86.8 % at 700 °C to 80.5 % at an annealing temperature of 1,000 °C, and a red shift was observed in the bandgap energy with increasing annealing temperature. These results suggest that the annealing temperature plays a crucial role in developing green light-emitting CaNb2O6:Tb3+ thin films for application in electroluminescent displays.

In this study, changes in the microstructure and mechanical properties of cast and extruded Al-2Li-1Ce alloy materials were investigated as the Mg content was varied. The density decreased to 2.485, 2.46 and 2.435 g/cm3 when the Mg content in the Al-2Li-1Ce alloy was increased to 2, 4 and 6 wt%, respectively. Intermetallic compounds of Al11Ce3 were observed in all alloys, while the β-phase of Al3Mg2 was observed in alloys containing 6 wt% of Mg. In the extruded material, with increasing Mg content the average grain size decreased to 84.8, 71.6 and 36.2 μm, and the fraction of high-angle grain boundaries (greater than 15°) increased to 82.8 %, 88.6 %, and 91.8 %, respectively. This occurred because the increased Mg content promotes dynamic recrystallization during hot extrusion. Tensile test results showed that as the Mg content increased, both the yield strength and tensile strength increased. The yield strength reached 86.1, 107.3, and 186.4 MPa, and the tensile strength reached 215.2, 285, and 360.5 MPa, respectively. However, it is worth noting that the ductility decreased to 27.78 %, 25.65 %, and 20.72 % as the Mg content increased. This reduction in ductility is attributed to the strengthening effect resulting from the increased amount of dissolved Mg, and grain refinement due to dynamic recrystallization.

A solution combustion process for the synthesis of hollandite (BaAl2Ti6O16) powders is described. SYNROC (synthetic rock) consists of four main titanate phases: perovskite, zirconolite, hollandite and rutile. Hollandite is one of the crystalline host matrices used for the disposal of high-level radioactive wastes because it immobilizes Sr and Lns elements by forming solid solutions. The solution combustion synthesis, which is a self-sustaining oxi-reduction reaction between a nitrate and organic fuel, generates an exothermic reaction and that heat converts the precursors into their corresponding oxide products in air. The process has high energy efficiency, fast heating rates, short reaction times, and high compositional homogeneity. To confirm the combustion synthesis reaction, FT-IR analysis was conducted using glycine with a carboxyl group and an amine as fuel to observe its bonding with metal element in the nitrate. TG-DTA, X-ray diffraction analysis, SEM and EDS were performed to confirm the formed phases and morphology. Powders with an uncontrolled shape were obtained through a general oxide-route process, confirming hollandite powders with micro-sized soft agglomerates consisting of nano-sized primary particles can be prepared using these methods.

Exploring earth-abundant, highly effective and stable electrocatalysts for electrochemical water splitting is urgent and essential to the development of hydrogen (H2) energy technology. Iron-cobalt layered double hydroxide (FeCo-LDH) has been widely used as an electrocatalystfor OER due to its facile synthesis, tunable components, and low cost. However, LDH synthesized by the traditional hydrothermal method tends to easily agglomerate, resulting in an unstable structure that can change or dissolve in an alkaline solution. Therefore, studying the real active phase is highly significant in the design of electrochemical electrode materials. Here, metal-organic frameworks (MOFs) are used as template precursors to derive FeCo-LDH from different iron sources. Iron salts with different anions have a significant impact on the morphology and charge transfer properties of the resulting materials. FeCo-LDH synthesized from iron sulfate solution (FeCo-LDH-SO4) exhibits a hybrid structure of nanosheets and nanowires, quite different from other electrocatalysts that were synthesized from iron chloride and iron nitrate solutions. The final FeCo-LDH-SO4 had an overpotential of 247 mV with a low Tafel-slope of 60.6 mV dec-1 at a current density of 10 mA cm-2 and delivered a long-term stability of 40 h for the OER. This work provides an innovative and feasible strategy to construct efficient electrocatalysts.