K0.5Bi0.5TiO3 (KBT) thin films were prepared by sol-gel processing for future use in piezoelectric generators. It is believed that the annealing temperature of films plays an important role in the output performance of piezoelectric generators. KBT films prepared on Ni substrates were annealed at 500 ~ 700 oC. Tetragonal KBT films were formed after annealing process. As the annealing temperature increased, the grain size of KBT films increased. KBT thin films show piezoelectric constant (d33) from 23 to 41 pC/N. The increase of grain size in KBT films brought about output voltage and current in the KBT generators. Also, the increase in the displacement of specimens during bending test resulted in increases in output voltage and current. Although KBT generators showed lower output power than those of generators prepared using NBT films, as reported previously, the KBT films prepared by sol-gel method show applicability as piezoelectric thin films for lead-free nanogenerators, along with NBT films.
The precipitation effect of Al-6%Si-0.4%Mg-0.9%Cu-(Ti) alloy (in wt.%) after various heat treatments was studied using a laser flash device (LFA) and differential scanning calorimetry (DSC). Solid solution treatment was performed at 535 oC for 6 h, followed by water cooling, and samples were artificially aged in air at 180 oC and 220 oC for 5 h. The titanium-free alloy Al-6%Si-0.4%Mg-0.9%Cu showed higher thermal diffusivity than did the Al-6%Si-0.4%Mg-0.9%Cu-0.2%Ti alloy over the entire temperature range. In the temperature ranges below 200 oC and above 300 oC, the value of thermal diffusivity decreased with increasing temperature. As the sample temperature increased between 200 oC and 400 oC, phase precipitation occurred. From the results of DSC analysis, the temperature dependence of the change in thermal diffusivity in the temperature range between 200 oC and 400 oC was strongly influenced by the precipitation of θ'-Al2Cu, β'-Mg2Si, and Si phases. The most important factor in the temperature dependence of thermal diffusivity was Si precipitation.
Cr thin films with O added are deposited on sapphire substrate by DC sputtering and are nitrided in NH3 atmosphere between 300 and 900 oC for various times. X-ray diffraction results show that nitridation begins at 500 oC, forming CrN and Cr2N. Cr oxides of Cr2O3 are formed at 600 oC. And, at temperatures higher than 900 oC, the intermediate materials of Cr2N and Cr2O3 disappear and CrN is dominant. The atomic concentration ratios of Cr and O are 77% and 23%, respectively, over the entire thickness of as-deposited Cr thin film. In the sample nitrided at 600 oC, a CrN layer in which O is substituted with N is formed from the surface to 90 nm, and the concentrations of Cr and N in the layer are 60% and 40%, respectively. For this reason, CrN and Cr2N are distributed in the CrN region, where O is substituted with N by nitridation, and Cr oxynitrides are formed in the region below this. The nitridation process is controlled by inter-diffusion of O and N and the parabolic growth law, with activation energy of 0.69 eV.
Cu matrix composites reinforced with chopped carbon fiber (CF), which is cost effective and can be well dispersed, are fabricated using electroless plating and hot pressing, and the effects of content and alignment of CF on the thermal properties of CF/Cu composites are studied. Thermal conductivity of CF/Cu composite increases with CF content in the in-plane direction, but it decreases above 10% CF; this is due to reduction of thermal diffusivity related with phonon scattering by agglomeration of CF. The coefficient of thermal expansion decreases in the in-plane direction and increases in the through-plane direction as the CF content increases. This is because the coefficient of thermal expansion of the long axis of CF is smaller than that of the Cu matrix, and the coefficient of thermal expansion of its short axis is larger than that of the Cu matrix. The thermal conductivity is greatly influenced by the agglomeration of CF in the CF/Cu composite, whereas the coefficient of thermal expansion is more influenced by the alignment of CF than the aggregation of CF.
Cu2ZnSn(S,Se)4 (CZTSSe) based thin-film solar cells have attracted growing attention because of their earthabundant and non-toxic elements. However, because of their large open-circuit voltage (Voc)-deficit, CZTSSe solar cells exhibit poor device performance compared to well-established Cu(In,Ga)(S,Se)2 (CIGS) and CdTe based solar cells. One of the main causes of this large Voc-deficit is poor absorber properties for example, high band tailing properties, defects, secondary phases, carrier recombination, etc. In particular, the fabrication of absorbers using physical methods results in poor surface morphology, such as pin-holes and voids. To overcome this problem and form large and homogeneous CZTSSe grains, CZTSSe based absorber layers are prepared by a sputtering technique with different RTA conditions. The temperature is varied from 510 oC to 540 oC during the rapid thermal annealing (RTA) process. Further, CZTSSe thin films are examined with X-ray diffraction, X-ray fluorescence, Raman spectroscopy, IPCE, Energy dispersive spectroscopy and Scanning electron microscopy techniques. The present work shows that Cu-based secondary phase formation can be suppressed in the CZTSSe absorber layer at an optimum RTA condition.
As the size of market for electric vehicles and energy storage systems grows, the demand for lithium-ion batteries (LIBs) is increasing. Currently, commercial LIBs are fabricated with liquid electrolytes, which have some safety issues such as low chemical stability, which can cause ignition of fire. As a substitute for liquid electrolytes, solid electrolytes are now being extensively studied. However, solid electrolytes have disadvantages of low ionic conductivity and high resistance at interface between electrode and electrolyte. In this study, Li7La3Zr2O12 (LLZO), one of the best ion conducting materials among oxide based solid electrolytes, is fabricated through RF-sputtering and various electrochemical properties are analyzed. Moreover, the electrochemical properties of LLZO are found to significantly improve with co-sputtered Li2O. An all-solid thin film battery is fabricated by introducing a thin film solid electrolyte and an Li4Ti5O12 (LTO) cathode; resulting electrochemical properties are also analyzed. The LLZO/Li2O (60W) sample shows a very good performance in ionic conductivity of 7.3 108 S/cm, with improvement in c-rate and stable cycle performance.
This study investigated the reaction between clay and Mn. Mn was coated using a manganese sulfate on porcelain plate and sintered from 1,100 oC to 1,250 oC. The body begin to shrink around 950 oC with the increase in temperature and rapidly progressed after 1,100 oC. Shrinkage of celadon body was performed at a lower temperature than for other substrates. Quartz, kaolin, and feldspar were the main crystalline phases of the starting materials, but they became mullite and crystobalite during the firing process, and some formed amorphous glass. When manganese sulfate was applied and fired, manganese oxide was fused, and some manganese oxide reacted with the substrate to show a dense microstructure different from that of the substrate; the substrate had pores. The manganese coated porcelain fired at 1,200 oC had L* values of 55.25, 36.87, and 37.13 for the white ware, celadon body, and white mixed ware, respectively; with a* values of 4.63, 3.07, and 2.15, and b* values of 7.93 and 3.98, it was found to be 3.42. This result indicated that the color of the surface was affected during firing by the chemical reaction between the substrate and manganese.
Laser cladding a surface treatment process that grants superior characteristics such as toughness, hardness, and corrosion resistance to the surface, and rebuilds cracked molds; as such, it can be a strong tool to prolong service life of mold steel. Furthermore, compared with the other similar coating processes – thermal spray, etc., laser cladding provides superior bonding strength and precision coating on a local area. In this study, surface characteristics are studied after laser cladding of low carbon steel using 18%Cr-2.5%Ni-Fe powder (Rockit404), known for its high hardness and excellent corrosion resistance. A diode laser with wavelength of 900-1070 nm is adopted as laser source under argon atmosphere; electrical power for the laser cladding process is 5, 6, and 10 kW. Fundamental surface characteristics such as crossectional microstructure and hardness profile are observed and measured, and special evaluation, such as a soldering test with molten ALDC12 alloy, is conducted to investigate the corrosion resistance characteristics. As a result of the die-soldering test by immersion of low carbon alloy steel in ALDC12 molten metal, the clad layer's soldering thickness decreases.
Herein, a series of g-C3N4 modified Bi2MoO6 nanocomposites using Bi2MoO6 and melamine as original materials are fabricated via sintering process. For presynthesis of Bi2MoO6 an ultrasonic-assisted hydrothermal technique is researched. The structure and composition of the nanocomposites are characterized by Raman spectroscopy, X-ray diffraction (XRD), and high-resolution field emission scanning electron microscopy (SEM). The improved photoelectrochemical properties are studied by photocurrent density, EIS, and amperometric i-t curve analysis. It is found that the structure of Bi2MoO6 nanoparticles remains intact, with good dispersion status. The as-prepared g-C3N4/Bi2MoO6 nanocomposites (BMC 5-9) are selected and investigated by SEM analysis, which inhibits special morphology consisting of Bi2MoO6 nanoparticles and some g-C3N4 nanosheets. The introduction of small sized g-C3N4 nanosheets in sample BMC 9 is effective to improve the charge separation and transfer efficiency, resulting in enhancing of the photoelectric behavior of Bi2MoO6. The improved photoelectronic behavior of g-C3N4/Bi2MoO6 may be attributed to enhanced charge separation efficiency, photocurrent stability, and fast electron transport pathways for some energy applications.
Background: Lunge exercises are lower extremity rehabilitation and strengthening exercises for patients and athletes. Most studies have shown the effectiveness of the forward and backward lunge exercises for treating patellofemoral pain and anterior cruciate ligament injuries (by increasing lower extremity muscle activity) and improving kinematics.
Objects: However, it is not known how the two different lunge movements affect trunk muscle activities in healthy individuals. The purpose of this study was to investigate the electromyographic activity of the rectus abdominis and erector spinae muscles during forward and backward lunge exercises in healthy participants.
Methods: Twelve healthy participants were recruited. Electromyographic activity of the rectus abdominis and erector spinae was recorded using surface electrodes during forward and backward lunges, and subsequently normalized to the respective reference voluntary isometric contractions of each muscle.
Results: Activity of the erector spinae was significantly higher than that of the rectus abdominis during all stages of the backward lunge (p < 0.05). The activity of the erector spinae was significantly greater during the backward than forward lunge at all stages (p < 0.05).
Conclusion: Backward lunging is better able to enhance trunk motor control and activate the erector spinae muscles.
Background: Considering the kinetic chain of the lower extremity, a pronated foot position (PFP) can affect malalignment of the lower extremity, such as a dynamic knee valgus (DKV). Although the DKV during several single-leg movement tests has been investigated, no studies have compared the differences in DKV during a single-leg step down (SLSD) between subjects with and without PFP.
Objects: The purpose of this study was to compare the DKV during SLSD between subjects with and without PFP.
Methods: Twelve subjects with PFP (9 men, 3 women) and 15 subjects without PFP (12 men, 3 women) participated in this study. To calculate the DKV, frontal plane projection angle (FPPA), knee-in distance (KID), and hip-out distance (HOD) during SLSD were analyzed by twodimensional video analysis software (Kinovea).
Results: The FPPA was significantly lower in PFP group, compared with control group (166.4° ± 7.5° and 174.5° ± 5.5°, p < 0.05). Also, the KID was significantly greater in PFP group, compared with control group (12.7 ± 3.9 cm and 7.3 ± 2.4 cm, p < 0.05). However, the HOD not significantly differed between two groups (12.7 ± 1.7 cm and 11.4 ± 2.5 cm, p > 0.05).
Conclusion: The PFP is associated with lower FPPA and greater KID. When assess the DKV during SLSD, the PFP should be considered as a crucial factor for occurrence of DKV.
Background: Individuals with scapular winging may have proprioceptive dysfunction which is important for motor control and causes shoulder instability. Reduced serratus anterior (SA) and lower trapezius (LT) muscle activity accompanied by over-active upper trapezius (UT), and pectoralis major (PM) may be contributing factors. Flexi-bar (FB) exercise may be used to increase joint position sense (JPS) and alter the target muscle activities.
Objects: This study aimed to investigate the immediate effects of flexi-bar exercise prior to knee push-up plus (FPK) versus knee push-up plus (KPP) on JPS and muscle activity of SA, LT, UT, and PM in subjects with scapular winging.
Methods: Eighteen subjects with scapular winging were recruited. JPS was investigated at baseline, after KPP and after FPK. Passive and active JPS errors were calculated by isokinetic equipment. Surface electromyography was used to record muscle activities during KPP and FPK. One-way repeated-measures analysis of variance and post hoc analyses were used to analyze the JPS error measured at baseline, after KPP and after FPK. Paired t-tests were used to compare muscle activities between KPP and FPK.
Results: Passive JPS error was significantly decreased after KPP (p = 0.005) and after FPK (p = 0.003) compared to the baseline. Active JPS error was also significantly decreased after KPP (p = 0.016) and after FPK (p = 0.012) compared to the baseline. There was no significant difference in the passive and active JPS errors between KPP and FPK. SA activity during FPK was significantly increased (p = 0.024), and LT activity during FPK was significantly increased (p = 0.006). There were no significant differences in the UT and PM activity.
Conclusion: FB might be recommended to immediately improve passive and active JPS and to selectively increase SA and LT muscle activities during KPP in individuals with scapular winging.
Background: Physical activity and quality of life (QOL) influence the health status of older adults. Recently, the use of wearable devices to monitor physical activity has increased.
Objects: This study examined the relationship between the amount of physical activity, measured using a wearable device, and QOL among older adults.
Methods: In total, 71 older adults (aged ≥ 65 years) were enrolled. The amount of physical activity was measured using a wearable device with a wrist strap, and daily physical activity was classified according to intensity (sedentary, light, moderate, or very active). Self-reported QOL was evaluated using the Short Form 36 (SF-36) questionnaire. Pearson and Spearman correlation analyses were conducted to analyze parametric and non-parametric variables, respectively. The relationship between amount of daily physical activity and SF-36 scores was assessed.
Results: The correlation analyses revealed positive correlations between the amount of moderate- intensity and very active physical activity (minutes/day) and SF-36 scores (p < 0.05). Conclusion: Physical activity of at least moderate intensity is associated with better QOL in older adults. Further studies are required to verify the effects of increased physical activity on QOL in older adults.
Background: The International Classification of Functioning, Disability, and Health-Child and Youth version (ICF-CY) is designed to record the characteristics of developing children and examine the influence of a child’s environment on their health.
Objects: This study was designed to determine the relationship between the clinically extracted ICF-CY items and The Pediatric Evaluation of Disability Inventory (PEDI) and Gross Motor Function Measure (GMFM) items.
Methods: Thirty patients (17 males and 13 females) who were hospitalized in a pediatric and youth patient unit of a rehabilitation hospital were included in the study. Four health professionals (two physical therapists and two occupational therapists) working independently linked the PEDI and GMFM-66 items to the activity and participation domains of the ICF-CY.
Results: There were strong negative correlations between the ICF-CY subdomains and the PEDI subdomains (r = 0.76–0.95; p < 0.05). There were positive strong correlations between the ICF-CY subdomains and the GMFM-66 (r = 0.76–0.95; p < 0.05).
Conclusion: The extracted ICF codes were a valid tool for evaluating the mobility and selfcare conditions of cerebral palsy in the pediatric rehabilitation area.
Background: The body schema, which is constantly updated using somatosensory information, enables accurate movement. Since pain is reported as a possible source to alter the body schema, the left right judgement test (LRJT) has been widely used in the pain rehabilitation. However, there was a lack of consistency in the effect of the pain on the LRJT results, and for the effect of the LRJT as a part of intervention programs for pain patients. The deeper understand of the LRJT is necessary for better reproducibility, and to expand the therapeutic applications of the LRJT in the pain and musculoskeletal rehabilitation.
Objects: This literature review aimed to understand the LRJT and to study the potential of the LRJT for therapeutic applications.
Methods: The PubMed database was searched for studies relevant to LRJT. To establish the query set, the term was regarded from various perspectives.
Results: The selected studies were classified into three categories: LRJT development, factors influencing LRJT, and therapeutic applications. Conclusion: Left right judgement test is the evaluation tool for the integrity of body schema as well as a tool for implicit motor imagery. Pain, proprioception, and other factors influence the performance of the LRJT.
Purpose: The aim of this study was to describe and understand the experiences of pain and the perceptions of treatment through a traditional Korean medicine clinical trial in patients with non-acute pain after back surgery. Methods: The data collection was recorded through in-depth interviews with 20 participants and transcribed with verbatim. The data were analyzed with qualitative contents analysis. Results: Patients with persistent or recurring pain after back surgery experienced physical and psychological symptoms that resulted in severe difficulties in daily and working life. Their persistent or recurring pain after surgery was a burden in their life and a major source of depression. Because of the difference in the perception of pain between doctors and patients, the patients continuously sought and received various treatments. The patients also wanted to receive customized self-management in exercise so that they could control pain themselves in daily life. Conclusion: A multidisciplinary approach that includes psychological counseling, pain management, individualized exercise, and education for proper posture should be needed to reduce low back pain in patients with pain after back surgery.
Purpose: Spiritual communication is very important in the end of life care or during spiritual distress. But there are few guides on spiritual communication. The purpose of this study was to present the process and method of spiritual communication. Methods: Literature review and content analysis were adopted in this study. In this study, 12 documents were extracted and analyzed in the foreign academic literature dealing with 'spiritual communication', 'spiritual conversation' as main keywords. The concepts of spirit, spirituality, spiritual need, and spiritual health were briefly presented based on the results of previous major studies. Results: Spiritual communication is communication on spiritual topics to satisfy spiritual needs, to alleviate spiritual distress, and to promote spiritual health. In other words, it is communication that allows spirituality to be expressed positively by overcoming obstacles that lead to spiritual health. The process of spiritual communication is divided into preparation for spiritual communication investigation of spiritual history, and communication on spiritual topics. Conclusion: Spiritual communication is very important in spiritual crisis. In particular, patients with severe illnesses such as advanced cancer, the end of life care and spiritual distress, want to talk with their health care providers about spiritual topics. The results of this study will provide important information for future research for the development of spiritual communication skills.
Purpose: This study explored and described the lived experiences of nurses in taking care of patients during COVID-19 pandemic in Korea. Methods: Data were collected through individual in-depth interviews with 10 nurses who involved in COVID-19 patient care. Verbatim transcripts were analyzed using Colaizzi’s phenomenological analysis. Results: Qualitative data analysis revealed three categories: ‘standing in front of the pandemic’, ‘harsh experience of caring for COVID-19 patients’, and ‘finding a way for better COVID-19 patients care’. The lived experience of nurses in caring of patients with COVID-19 infection was ‘finding the best way to provide proper care in unfamiliar and difficult pandemic situation’. Conclusion: The results illustrated the motivation, meaning, and value of pandemic care from the nurses’ perspective. Nurses felt proud of being a part of dedicated hard-working team but distressed by crumbling death without dignity and pressured by being thrown at the front-line in the COVID-19 battle. The advanced practice nurses’ hidden supports and advices were helpful for them to reinforce nursing capacity for optimal care. Nursing professionalism should be enhanced by establishing the scope of practices and providing systematic support with appropriate rewards.
Purpose: The purpose of this study was to understand the forest healing instructor's experiences of providing a forest healing program. Methods: The participants were 12 forest healing instructors who experienced managing a forest healing program at B mountain in C city. Data were collected using focus group interviews and individual in depth interviews and data were analyzed using qualitative content analysis method. Results: As the results of this study, 5 themes and 18 sub-themes were derived. The derived 5 themes were as follows; 1. Choosing a new path as a turning point in life 2. Ambiguity as a new forest healing instructor, 3. Feeling a reward as a forest healing instructor and feeling self-healing. 4. Facing difficulties in operating forest healing programs, 5. Having on-going tasks for the establishment of forest healing programs. Conclusion: In order to provide good forest healing program, we need to develop additional education programs for enhancing professionality as a forest healing instructor and continous long term economical supports and investment for forest healing instructors by the Korea Forest Service.
Purpose: The purpose of this study is to understand the general nurses's experiences of missing patient identification. Methods: Participants were 12 nurses who experienced missing patient identification in general wards in hospitals. Data were collected with focus group interviews and individual in-depth interviews and data were analyzed using qualitative content analysis. Results: As the results of this study, 128 statements, 4 themes and 13 sub-themes were derived. The four themes derived were ‘Situations that we had not to check patient identification properly’, ‘Fear and pressure from the result of missing patient identification’, ‘Feeling guilty to the results of missing patient identification’and ‘Efforts to reassuring patient identification’. Conclusion: In order to prevent the failure of patient identification, we need specialized programs to cultivate patient safety culture not only for nurses, also patients and caregivers, and all departments of hospital. We also need institutional efforts and effective hospital investment and supports for accomplishing the goal.