• Composites Research
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• v.26 no.6
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• pp.355-362
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• 2013

Carbon particle based nanocomposites have been studied. Nanocomposites containing CNT and graphite particles were manipulated by aligning the micro/nano-size particles with electric field. Electric field is applied to the suspension of epoxy matrix and particulate inclusions in order to align them along the direction of the electric field. Particles aligned in a uniform direction act as a fiber in a CFRP composite. The mechanical strength and physical characteristics highly depend on particles' distribution pattern and amount. In this study, the characteristics of radioactive barrier are emphasized, which has been rarely discussed in the literature. A number of sample coupons were tested to verify their performance. The procedure of manufacturing nanocomposites by means of extremely small size particle alignment is presented in sequence. Several physical and structural performances of composites containing aligned and randomly distributed particles were compared. The results show particle alignment is very effective to enhance directional strength and radioactive barrier performance.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.4
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• pp.265-272
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• 2019

Purpose : Excessive computer use frequently results in musculoskeletal disorders of the neck and shoulder such as forward head posture (FHP). The purpose of this study was to investigate effects of neck and shoulder exercise program on spino-pelvic alignment and the correlation between change in head and neck posture and spino-pelvic alignment in FHP. Methods : The study included 44 participants with FHP. The participants performed the exercise for correction of FHP 2-3 times a week for 4 weeks. We examined whole spine X-ray images in the lateral standing position with both arms crossed. We measured anterior head translation distance (AHT), craniovertebral angle (CVA), cervical lordosis (CL), thoracic kyphosis (TK), lumbosacral lordosis (LSL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI) of the subjects. The association between change in AHT and each spino-pelvic parameter was also subjected to Pearson's correlation coefficient analysis. Results : There were statistically significant differences before and after exercise in the parameters of AHT, CVA, and SS (p<.05). Significant negative correlation was observed between the change in AHT and CVA (r=-.768, p<.001), and CL (r=-.388, p<.05). There was significant positive correlation between the change in AHT and SS (r=.328, p<.05), and PI (r=.333, p<.05). However, no significant correlation was observed in change in AHT with that of TK, LSL, and PT. Conclusion : Based on the above results, we conclude that there is a relationship between change in AHT, which is a parameter associated with forward displacement of the head, and that of CVA, CL, SS, and PI after exercise in cases of FHP.

• Journal of International Academy of Physical Therapy Research
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• v.7 no.2
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• pp.1018-1024
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• 2016

The purpose of this study was to identify the effects of cervical alignment, pain, and physique to apply proprioceptive neuromuscular facilitation(PNF) techniques in patients with forward head posture (FHP). The subjects of this study were 24 patients diagnosed with FHP. They were randomly divided into two groups: a PNF group(n=12) and a control group(n=12). The intervention was performed a total of 24 times, 30 min a day, six times a week for four weeks. Data on cervical alignment(forward head displacement, FHD), pain(visual analog scale, VAS), and physique(height, weight, and body mass index) were obtained pre- and post-intervention. Two-way repeated measures ANOVA was used to compare the groups and time. For FHD, the VAS, and physique(height and BMI), there was an interaction effect for the groups and time(p<.001, BMI: p<.05) and main effects for time(p<.001, BMI: p<.05). For weight, there were main effects of time(p<.01). For FHD(p<.01) and the VAS(p<.05), there were main effects for the groups. In the PNF group, there were significant improvements in FHD, VAS, and physique. In the control group, there was a significant increase in FHD. The results of this study indicated that PNF intervention using scapular and upper extremity patterns effective in FHP positively. The use of a therapeutic intervention on physique changes may also be effective in improving poor posture and help to better patients' quality of life.

• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.307-314
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• 2013

Infrared optical systems are operated at low temperature and vacuum (LT-V) condition, whereas the assembly and alignment are performed at room temperature and non-vacuum (RT-NV) condition. The differences in temperature and pressure between assembly/alignment environments and operation environment change the physical characteristics of optical and opto-mechanical parts (e.g., thickness, height, length, curvature, and refractive index), and the resultant optical performance changes accordingly. In this study, using input relay optics (IO), among the components of the Immersion GRating INfrared Spectrograph (IGRINS) which is an infrared spectrograph, a simulation based on the physical information of this optical system and an actual experiment were performed; and optical performances in the RT-NV, RT-V, and LT-V environments were predicted with an accuracy of $0.014{\pm}0.007{\lambda}$ rms WFE, by developing an adaptive fitting line. The developed adaptive fitting line can quantitatively control assembly and alignment processes below ${\lambda}/70$ rms WFE. Therefore, it is expected that the subsequent processes of assembly, alignment, and performance analysis could not be repeated.

• Physical Therapy Korea
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• v.23 no.4
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• pp.38-46
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• 2016

Background: Shoulder stabilization commonly involves two components: the glenohumeral stabilization exercise (GSE) and scapular stabilization exercise (SSE). Despite the fact that the shoulder stabilization has advantageous merit, to our knowledge, only a few studies have compared the superior of the GSE and the SSE. Objects: The purpose of this study was to assess the effects of GSE in patients with nonspecific shoulder pain. Methods: Thirty subjects with nonspecific shoulder pain were randomly divided into an experimental group and control group, each with 15 patients. The experimental group used an GSE, whereas the control group did SSE. All subjects were measured in shoulder stability, scapular symmetric alignment, pain, muscle power, and range of motion before and after the intervention. Results: GSE resulted in significantly better shoulder stability (p=.046, from $8.67{\pm}7.54$ score to $13.93{\pm}9.40$) in the experimental group compared with SSE in the control group. However, no significant effects were observed for scapular symmetric alignment including the angles of inferior scapular distance (p=.829) and inferior scapular height difference (p=.735), pain (p=.113), muscle power including shoulder flexion (p=.723) and abduction (p=.897) and range of motion including shoulder flexion (p=.853) and abduction (p=.472). Conclusion: These findings suggest that GSE may be more effective in increasing the shoulder stability than the SSE in patients with nonspecific shoulder pain, probably through a centralization effect on the shoulder mechanism.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.4
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• pp.19-26
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• 2016

PURPOSE: The purpose of this study was to compare the effect of correction on posture parameters between a horse riding simulator exercise and a conventional exercise occurring in an open linear chain linking the head to the pelvis in the sagittal plane of young adults with a forward head posture. METHODS: In this study, 30 subjects were randomly divided into two groups of 15 subjects each, were assigned to the horse riding simulator exercise or the neck exercise group and they performed exercise 30 minutes per each round two times a week for six weeks. To determine the subjects' forward head posture, the three angles and three distances were measured. RESULTS: The forward head angle and head distance results showed a significant change between pre and post intervention in both group. The horizontal distance between acromion and tragus results showed a significant change between pre and post intervention in neck exercise group (CG), but no significant change in horse riding simulator exercise group (EG). The averages of each measured values of EG and CG before and after were compared, but there are no significant different between groups. CONCLUSION: Although the effects of the horse riding exercise were lower than those elicited by the neck exercise, the results demonstrated that the horse riding simulator exercise improved posture alignment for subjects with forward head posture. Therefore, the horse riding simulator exercise can constitute an appropriate alternative exercise for subjects with forward head posture.

• The Journal of Korean Physical Therapy
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• v.31 no.2
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• pp.122-128
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• 2019

Purpose: This study examined the effects of sagittal spinopelvic alignment on the clinical parameters, motor symptoms, and respiratory function in patients with mild to moderate Parkinson's disease (PD). Methods: This study was a prospective assessment of treated patients (n=28, Hoehn and Yahr (H&Y) stage 2-3) in a PD center. Twenty-eight subjects ($68.5{\pm}5.7yrs$) participated in this study. The clinical and demographic parameters, including age, sex, symptoms duration, treatment duration, and H&Y stage, were collected. Kinematic analysis was conducted in the upright standing posture with a motion capture system. A pulmonary function test (PFT) was performed in the sitting position using a spirometer. The motor symptoms were assessed on part III of the movement disorder society sponsored version of the unified Parkinson's disease rating scale (MDS-UPDRS). SPSS 18.0 was used to analyze the collected data. Results: The exceeding 12 degrees group of the lower trunk showed significantly higher on the clinical parameters than the below 12 degrees group. In addition, the exceeding 12 degrees group of the lower trunk showed a significantly lower forced expiratory volume at one second (FEV1) / forced vital capacity (FVC) (%) and 25-75% forced mid-expiratory flow (FEF) (L/s) than in the below group. On the other hand, there was no difference in the upper trunk and the cervical pelvis between the groups. Conclusion: These findings suggest that the sagittal balance in the lower trunk is related to the clinical parameters and respiratory function, but not the motor symptoms in patients with mild to moderate PD.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.38.1-38.1
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• 2021

Dust polarization depends on the physical and mechanical properties of dust, as well as the properties of local environments. To understand how dust polarization varies with grain mechanical properties and the local environment, in this paper, we model the wavelength-dependence polarization of starlight and polarized dust emission by aligned grains by simultaneously taking into account grain alignment and rotational disruption by radiative torques (RATs). We explore a wide range of the local radiation field and grain mechanical properties characterized by tensile strength. We find that the maximum polarization and the peak wavelength shift to shorter wavelengths as the radiation strength U increases due to the enhanced alignment of small grains. Grain rotational disruption by RATs tends to decrease the optical-near infrared polarization but increases the ultraviolet polarization of starlight due to the conversion of large grains into smaller ones. In particular, we find that the submillimeter (submm) polarization degree at 850㎛(P850) does not increase monotonically with the radiation strength or grain temperature (Td), but it depends on the tensile strength of grain materials. Our physical model of dust polarization can be tested with observations toward star-forming regions or molecular clouds irradiated by a nearby star, which have higher radiation intensity than the average interstellar radiation field. Finally, we compare our predictions of the P850-Td relationship with Planck data and find that the observed decrease of P850 with Td can be explained when grain disruption by RATs is accounted for, suggesting that interstellar grains unlikely to have a compact structure but perhaps a composite one. The variation of the submm polarization with U (or Td)can provide a valuable constraint on the internal structures of cosmic dust

• Physical Therapy Rehabilitation Science
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• v.5 no.3
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• pp.132-137
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• 2016

Objective: Eversion of the foot is created with internal rotation of the shank, and inversion of the foot is created with external rotation of the shank. The purpose of the study was to investigate the effect of continuous changes in the angle of the subtalar joint on lower extremity alignments. Design: Cross-sectional study. Methods: Seventeen healthy young adult subjects recruited. The subjects were asked to stand up in a natural standing position on a footplate with eye open and equal weight on each foot for 10s in two different conditions: The right subtalar joint was everted continuously $0^{\circ}-20^{\circ}$ and in separate segments of $0^{\circ}$, $5^{\circ}$, $10^{\circ}$, $15^{\circ}$, $20^{\circ}$. The averages of three trials were used. The observation of the changes in the lower extremity was performed with the use of 3-dimensional motion analysis. For data analysis, the SPSS 18.0 software using paired t-test and repeated measures analysis of variance (ANOVA) was applied. Results: The angle was significantly increased at the horizontal rotation angle of the shank, thigh, and ankle without anterior rotation of the pelvis (p<0.05). The maximum horizontal rotation angle at the thigh on $20^{\circ}$ was $-4.52^{\circ}$ in static, and $-3.10^{\circ}$ in the dynamic conditions compared to $0^{\circ}$. Conclusions: Increased unilateral foot pronation, thigh, shank, ankle horizontal rotation variance was significantly effective. The observation of the changes in foot abduction with the use of a 3-dimensional motion analysis augmented in predicting the angle values of each segment of the lower extremity. In further studies, a comparison of the right and left subtalar joints need to be investigated.

• Physical Therapy Korea
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• v.30 no.3
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• pp.174-183
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• 2023

Background: Office workers experience neck or back pain due to poor posture, such as flexed head and forward head posture, during long-term sedentary work. Posture correction is used to reduce pain caused by poor posture and ensures proper alignment of the body. Several assistive devices have been developed to assist in maintaining an ideal posture; however, there are limitations in practical use due to vast size, unproven long-term effects or inconsistency of maintaining posture alignment. We developed a headphone and necklace posture correction system (HANPCS) for posture correction using an inertial measurement unit (IMU) sensor that provides visual or auditory feedback. Objects: To demonstrate the test-retest reliability and concurrent validity of neck and upper trunk flexion measurements using a HANPCS, compared with a three-dimensional motion analysis system (3DMAS). Methods: Twenty-nine participants were included in this study. The HANPCS was applied to each participant. The angle for each action was measured simultaneously using the HANPCS and 3DMAS. The data were analyzed using the intraclass correlation coefficient (ICC) = [3,3] with 95% confidence intervals (CIs). Results: The angular measurements of the HANPCS for neck and upper trunk flexions showed high intra- (ICC = 0.954-0.971) and inter-day (ICC = 0.865-0.937) values, standard error of measurement (SEM) values (1.05°-2.04°), and minimal detectable change (MDC) values (2.92°-5.65°). Also, the angular measurements between the HANPCS and 3DMAS had excellent ICC values (> 0.90) for all sessions, which indicates high concurrent validity. Conclusion: Our study demonstrates that the HANPCS is as accurate in measuring angle as the gold standard, 3DMAS. Therefore, the HANPCS is reliable and valid because of its angular measurement reliability and validity.