• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.1
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• pp.23-28
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• 2008

Functional hanji was manufactured using the bast fiber of Broussonetia kazinoki and various inorganic compounds such as kaolin, talc, elvan, and ocher, and the physical and optical properties were investigated. The residual percentages of kaolin, talc, elvan and ocher in the functional hanji were above 50%. The density of the hanji increased with the increase of the content of inorganic compounds. The hanji manufactured using ocher showed the highest density. The breaking length and burst factor decreased with the increase of inorganic materials, indicating that physical properties of hanji were not improved by adding inorganic materials. The emission rates of far-infrared radiation increased in the hanji manufactured using inorganic materials. The higher emission rates were observed in the hanji with elvan or ocher. Addition of inorganic compounds to hanji showed the flame retardative effect. The colorfastness to light of the hanji with elvan or ocher was the degree of 4, which explained by the characteristic color of the inorganics.

• Journal of the Korean Society of Physical Medicine
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• v.7 no.3
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• pp.251-258
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• 2012

Purpose : The purpose of this study is to provide an efficient and basis for muscle activity of Quadriceps muscles and balance in anterior cruciate ligament reconstruction patients through unstable surface exercise and stable surface exercise. Methods : This study included 30 anterior cruciate ligament reconstruction patients belonging to A hospital and D orthopedic surgery clinic of province who attended the program for 30 minutes at a time and three times a week for 4 weeks. Of these 15 attended the unstable surface exercise program and 15 the stable surface exercise program. To increase muscle activity (%MVIC) and balance (WPL), the unstable surface exercise. Results : The %MVIC of lower extrmity muscle(RF, VL, VM) increased from before training to after training in the case of the participants who performed the unstable surface exercise, and the whole path length (WPL) decreased from before the training to after the training(p<.05). Conclusion : In conclusion, unstable surface exercise program helps to improve the balancing ability and musle activity in a anterior cruciate ligament recunstruction patients who requires both muscle activity and balance than stable surface exercise program.

• Steel and Composite Structures
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• v.33 no.1
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• pp.93-109
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• 2019

In the present study, vibration analysis of double bonded micro sandwich cylindrical shells with saturated porous core and carbon/boron nitride nanotubes (CNT/BNNT) reinforced composite face sheets under multi-physical loadings based on Cooper-Naghdi theory is investigated. The material properties of the micro structure are assumed to be temperature dependent, and each of the micro-tubes is placed on the Pasternak elastic foundations, and mechanical, moisture, thermal, electrical, and magnetic forces are effective on the structural behavior. The distributions of porous materials in three distributions such as non-linear non-symmetric, nonlinear-symmetric, and uniform are considered. The relationship including electro-magneto-hydro-thermo-mechanical loadings based on modified couple stress theory is obtained and moreover the governing equations of motion using the energy method and the Hamilton's principle are derived. Also, Navier's type solution is also used to solve the governing equations of motion. The effects of various parameters such as material length scale parameter, temperature change, various distributions of nanotube, volume fraction of nanotubes, porosity and Skempton coefficients, and geometric parameters on the natural frequency of double bonded micro sandwich cylindrical shells are investigated. Increasing the porosity and the Skempton coefficients of the core in micro sandwich cylindrical shell lead to increase the natural frequency of the structure. Cylindrical shells and porous materials in the industry of filters and separators, heat exchangers and coolers are widely used and are generally accepted today.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.1
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• pp.17-22
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• 2021

PURPOSE: This study examined the correlations between gait, static balance, and pelvic inclination in patients with chronic stroke. METHODS: Twenty-two chronic stroke patients were included in this study. The subjects participated in gait, static balance, and pelvic inclination tests. In the gait measurement, the cadence and gait velocity were measured, and the average of three trials was calculated and recorded. The static balance was measured using a force platform. The data was captured for ten seconds, and five successful trials were recorded. Pelvic inclination in the sagittal plane was measured using a palpation meter. For data processing, a KolmogorovSmirnov test was used to determine the type of distribution for all variables. Pearson's correlation coefficient was used for correlation analysis. The correlations among the gait, static balance, and pelvic inclination was calculated. The level of significance was .05. RESULTS: Significant negative correlations were observed between the gait variables (cadence, velocity) and static balance variables (COP path length, COP average velocity, and 95% confidence ellipse area) (p < .05). On the other hand, there was no significant correlation between pelvic inclination and gait or between the pelvic inclination and static balance variables. CONCLUSION: Significant correlations were observed between the gait function and static balance. On the other hand, there were no significant correlations between the pelvic inclination and gait and static balance. These results suggest that the pelvic inclination is not an important consideration for increasing the gait function and static balance.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.26 no.2
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• pp.29-36
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• 2020

Background: The purpose of this study was to determine the effects of whole body vibration (WBV) exercise on lower extremity muscle activity and gait ability in stroke patients. Methods: For this study, 30 stroke patients participated in this study and they were divided into WBV exercise group and sham-WBV exercise group, each group in which consisted of 15 patients. WBV group and sham-WBV group was performed by the patients for five times a week, for six weeks. sEMG was used to measure lower extremity muscle activity. Changes in the activities of the muscles, such as the vatus lateralis (VL), vastus medialis (VM), bicep femoris (BF), gastrocnemius (GCM) muscle, were analysis. Motion analysis system was used to measure gait ability. Gait ability measured the stride length (SL) and walking velocity (WV). Results: According to the results of the comparisons between the groups, after intervention, lower extremity muscle activity of VL (p<.01), VM (p<.01), GCM (p<.01). SL, WV was significant between the group (p<.01). Conclusion: This study showed the WBV exercise is effective for improving increase of muscle activity and gait ability in stroke patients.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.4
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• pp.2244-2252
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• 2020

Background: Thera-Band, Narrow squats, Kinesiology taping helps in the reduction of loading on the knee joints. Despite the fact that the varus knee negatively affects the alignment of the lower extremities, most of the studies have analyzed each independently. Objectives: To investigate the effects of a complex exercise program consisting of elastic band exercises and squat exercises on the distance between the inner knees and balance in young adults with genu varum. Design: A cluster randomized controlled trial. Methods: The complex exercise group performed resistance exercises using an elastic band. The taping group used kinesiology tape on the vastus lateralis and biceps femoris. To select those to be included in the study, we measured the distance between the knees using digital Vernier calipers and to measure the balance ability, we used a balance training system. The data were analyzed with the independent t-test and paired t-test. Results: The study indicated a significant difference in the distance between the knees between the two groups, but no significant differences in the dynamic balance between the groups. Also, the static balance comparison between the groups according to the intervention method included the trace length, C90 area, C90 angle and velocity. There were no significant differences in the static balance between the groups. In addition, the complex exercise program was more effective than taping. Conclusion: The results of this study demonstrate that the complex exercise program and taping decrease the between both the knee and increase the balance.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3367-3382
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• 2023

Smoothed Particle Hydrodynamics (SPH) is a Lagrangian computational fluid dynamics method that has been widely used in the analysis of physical phenomena characterized by large deformation or multi-phase flow analysis, including free surface. Despite the recent implementation of eddy-viscosity models in SPH methodology, sophisticated turbulent analysis using Lagrangian methodology has been limited due to the lack of computational performance and numerical consistency. In this study, we implement the standard and dynamic Smagorinsky model and dynamic Vreman model as sub-particle scale models based on a weakly compressible SPH solver. The large eddy simulation method is numerically identical to the spatial discretization method of smoothed particle dynamics, enabling the intuitive implementation of the turbulence model. Furthermore, there is no additional filtering process required for physical variables since the sub-grid scale filtering is inherently processed in the kernel interpolation. We simulate lid-driven flow under transition and turbulent conditions as a benchmark. The simulation results show that the dynamic Vreman model produces consistent results with experimental and numerical research regarding Reynolds averaged physical quantities and flow structure. Spectral analysis also confirms that it is possible to analyze turbulent eddies with a smaller length scale using the dynamic Vreman model with the same particle size.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.1
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• pp.16-24
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• 2022

A computational study of combined thermal and solutal convection (double diffusive convection) in a sealed crystal growth reactor is presented, based on a two-dimensional numerical analysis of the nonlinear and strongly coupled partial differential equations and their associated boundary conditions. The average Nusselt numbers for the source regions are greater than those at the crystal regions for 9.73 × 10³ ≤ Gr_t ≤ 6.22 × 10⁵. The average Nusselt numbers for the source regions varies linearly and increases directly with the thermal Grashof number form 9.73 × 10³ ≤ Gr_t ≤ 6.22 × 10⁵ for aspect ratio, Ar (transport length-to-width) = 1 and 2. Additionally, the average Nusselt numbers for the crystal regions at Ar = 1 are much greater than those at Ar = 2. Also, the occurrence of one unicellular flow structure is caused by both the thermal and solutal convection, which is inherent during the physical vapor transport of Hg₂Br₂. When the aspect ratio of the enclosure increases, the fluid movement is hindered and results in the decrease of thermal buoyancy force.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.3
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• pp.55-61
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• 2023

Background: The purpose of this study was to determine whether applying ultrasound after stretching the erector spinae muscle is an effective method for normal adults as a way to restore reduced back flexibility that causes back pain. Methods: The study was conducted on 60 healthy volunteers divided randomly into four groups (control group, stretching group, ultrasound group, ultrasound after stretching group). The flexibility-promoting effects were determined by assessing, each group, at the time of treatment, pre and post by modified fingertip to-floor (MFTF) and active straight leg raising (ASLR). The data were analyzed using the two-way ANOVA repeated measure with significant level α=.05. Results: Each group showed statistically significant changes in MFTF distance and ASLR degree. In the post-hoc test about this result, the length of MFTF and degree of ASLR in ultrasound after stretching group increased significantly compared to the others. Conclusion: The results suggest that using ultrasound after stretching is far more effective in increasing the flexibility of the erector spinae than using stretching or ultrasound intervention.

• The Journal of Korean Physical Therapy
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• v.36 no.1
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• pp.27-32
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• 2024

Purpose: This study was conducted to verify the effect of applying a pressure biofeedback unit on walking ability and knee joint function while performing knee joint extensor strengthening exercises using resistance exercise equipment in total knee replacement (TKR) patients. Methods: This study was conducted on twelve patients receiving rehabilitation treatment after being admitted to a rehabilitation hospital post-TKR. Of these, six were allocated to a feedback group with a pressure biofeedback unit, and the other 6 were allocated to a control group without a pressure biofeedback unit. The subjects performed an exercise program for 45 minutes per session, five times a week, for two weeks. Walking ability and knee joint function were evaluated and analyzed before and after exercise. Results: The feedback group showed significantly better improvements in walking speed, gait cycle, step length on the non-operation side, time on the foot on the operation side, K-WOMAC stiffness, and K-WOMAC function than the control group (p<0.05). Conclusion: When strengthening the knee joint extensor muscles using resistance exercise equipment in TKR patients, the provision of a pressure biofeedback unit was found to improve walking ability and knee joint function by inducing concentric-eccentric contraction of the knee joint extensor muscles. Therefore, the study shows that exercise based on the provision of a pressure biofeedback unit should be considered when strengthening knee joint extensor muscles to improve the walking ability and knee joint function of TKR patients in clinical practice.