• International Journal of Precision Engineering and Manufacturing
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• 제8권2호
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• pp.54-58
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• 2007

This paper describes an atomic force microscope (AFM)-based instrument for measuring the nanoscale cutting edge profiles of diamond cutting tools. The instrument consists of a combined AFM unit and an optical sensor to align the AFM tip with the top of the diamond cutting tool edge over a submicron range. In the optical sensor, a aser beam is emitted from a laser diode along the Y-axis and focused to a small beam spot with a diameter of approximately $10{\mu}m$ at the beam waist, which is then received by a photodiode. The top of the tool edge is first brought into the center of the beam waist by adjusting it in the X-Z-plane while monitoring the variation in the photodiode output. The cutting tool is then withdrawn and its top edge position at the beam center is recorded. The AFM tip can also be positioned at the beam center in a similar manner to align it with the top of the cutting edge. To reduce electronic noise interference on the photodiode output and thereby enhance the alignment accuracy, a technique is applied that can modulate the photodiode output to an AC signal by driving the laser diode with a sinusoidal current. Alignment experiments and edge profile measurements of a diamond cutting tool were carried out to verify the performance of the proposed system.

• 대한물리의학회지
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• 제10권2호
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• pp.17-27
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• 2015

PURPOSE: The purpose of this study was to compare the effects of three interventions (intervention by passive range of motion exercise plus manual cervical traction, Mulligan's joint mobilization, and strengthening exercises) after Kaltenborn's joint mobilization on the cervical spine alignment, and muscle activity in patients with a forward head posture. METHODS: The subjects were 39 students from H University in Chungnam and C University in Jeonbuk. The subjects in each group attended training sessions three times a week for four weeks. We used one-way ANOVA and Scheffe's post hoc test to compare values between groups, and used paired t-test to compare the values of the dependent variables within groups. RESULTS: The results showed that the active intervention group experienced a significant increase compared to the passive intervention group in terms of the craniovertebral angle, cervical lordosis angle, and had significant decreases compared to the passive intervention group in terms of the upper trapezius muscle activity. The active intervention group also had significant increases in craniovertebral angle and decreased anterior scalene muscle activity than the active-assistive intervention group. The active-assistive intervention group had significant decreases compared to the active intervention group in terms of the serratus anterior, levator scapulae, and splenius capitis muscle activity. CONCLUSION: It appears that the subjects with a forward head posture had significant improvements in the cervical lordosis angle, cranial rotation angle, craniovertebral angle, and muscle activity after intervention by Mulligan's joint mobilization (active-assistive intervention component) and strengthening exercises (active intervention component) after applying Kaltenborn's joint mobilization.

• Journal of Korean Neurosurgical Society
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• 제64권5호
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• pp.677-692
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• 2021

Many studies have focused on pre-operative sagittal alignment parameters which could predict poor clinical or radiological outcomes after laminoplasty. However, the influx of too many new factors causes confusion. This study reviewed sagittal alignment parameters, predictive of clinical or radiological outcomes, in the literature. Preoperative kyphotic alignment was initially proposed as a predictor of clinical outcomes. The clinical significance of the K-line and K-line variants also has been studied. Sagittal vertical axis, T1 slope (T1s), T1s-cervical lordosis (CL), anterolisthesis, local kyphosis, the longitudinal distance index, and range of motion were proposed to have relationships with clinical outcomes. The relationship between loss of cervical lordosis (LCL) and T1s has been widely studied, but controversy remains. Extension function, the ratio of CL to T1s (CL/T1s), and Sharma classification were recently proposed as LCL predictors. In predicting postoperative kyphosis, T1s cannot predict postoperative kyphosis, but a low CL/T1s ratio was associated with postoperative kyphosis.

• 천문학회지
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• 제54권4호
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• pp.113-119
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• 2021

It is difficult for observers to conduct an optical alignment at an observatory without the assistance of an optical engineer if optomechanical parts are to be replaced at night. We present a practical tilt correction method to obtain the optimal optical alignment condition using the symmetricity of optical aberrations of a wide-field on-axis telescope at night. We conducted coarse tilt correction by visually examining the symmetry of two representative star shapes obtained at two guide chips facing each other, such as east-west or north-south pairs. After coarse correction, we observed four sets of small stamp images using four guide cameras located at each cardinal position by changing the focus positions in 10-㎛ increments and passing through the optimum focus position in the range of ±200 ㎛. The standard deviation of each image, as a function of the focus position, was fitted with a second-order polynomial function to derive the optimal focus position at each cardinal edge. We derived the tilt angles from the slopes converted by the distance and the focus position difference between two paired guide chip combinations such as east-west and north-south. We used this method to collimate the on-axis wide-field telescope KMTNet in Chile after replacing two old focus actuators. The total optical alignment time was less than 30 min. Our method is practical and straightforward for maintaining the optical performance of wide-field telescopes such as KMTNet.

• 천문학회보
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• 제46권2호
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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

• 대한정형도수물리치료학회지
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• 제23권2호
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• pp.9-16
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• 2017

Background: The purpose of this study was to investigate the relationship between the spine and the flat-foot, the stability and the alignment of the posture of the neck to prevent the alignment of the ankle joint operation and the lower back flexibility of the lumbar region according to the type of treatment using active stretching of the triceps, back pain, and to see how they affect weight bearing differences. Methods: The subjects of this study were 24 chronic low back pain patients. They were randomly divided into experimental group and control group. In the experimental group, ankle joint mobilization and active scraping of triceps were performed three times a week for a total of 6 weeks. The control group was performed in the same way without articulation. The range of flexion and extension motion of the lumbar spine and pain degree and difference of weight-bearing were measured before and after the experiment. Results: The model of ankle joint mobilization and calf muscle elongation of flat foot significantly improved the range of flexion and extension motion of the vertebrae (p<.05) and the VAS and distribution of weight-bearing were decreased in both of two groups (p<.05). In other words, the exercise and mobilization help to recover of the balance of the whole musculoskeletal, the vertebrae. Conclusions: The active exercise of the triceps muscle of the lower leg in this study It affects the flexibility of the lumbar spine, the pain and the difference in the weight support of the lower extremities, when we performed ankle joint mobilization for exercise and cramping, pain and the difference in weight support between the two lower limbs.

• 대한물리치료과학회지
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• 제31권1호
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• pp.33-45
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• 2024

Background: This study aimed to investigate the effect of elastic band-resistive exercise using audio-visual medium on pain, proprioception, and motor function in adults with chronic neck and shoulder pain. Design: One group pretest-posttest follow-up experimental design. Method: Twenty adult women with neck and shoulder pain voluntarily participated in this study. Elastic band-resistive exercise using audio-visual medium including cervical flexion and extension, shoulder external rotation, and scapular retraction-protraction motions was conducted 5 times a week for 3 weeks. The Numerical Rating Scale, pressure threshold tool, CROM goniometer, and Image J software were used to assess subjective pain level, tenderness threshold (pain), joint position sense error (proprioception), joint range of motion, and postural alignment (motor function), respectively. Result:: The pain intensity and threshold and joint position sense error showed significant decreases after the intervention, whereas the joint range of motion angle revealed significant increases. The postural alignment including forward head posture and rounded shoulder revealed significant improvements after the intervention. Conclusions: Therefore, we suggest that elastic band-resistive exercise through audio-visual medium would be helpful in preventing and managing pain and physical dysfunction in individuals with chronic neck and shoulder pain, and then it would support the development of health management-related online education content.

• Fibers and Polymers
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• 제6권3호
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• pp.186-199
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• 2005

A selection of commercially available poly(ethy1ene terephtha1ate) fibers with different degrees of molecular alignment and crystallinity have been investigated utilizing a wide range of techniques including optical microscopy, infrared spectroscopy together with thermal and wide-angle X-ray diffraction techniques. Annealing experiments showed increased molecular alignment and crystallinity as shown by the increased values of birefringence and melting enthalpies. Crystallinity values determined from thermal analysis, density, unpolarized infrared spectroscopy and X-ray diffraction are compared and discussed in terms of the inherent capabilities and limitations of each measurement technique. The birefringence and refractive index values obtained from optical microscopy are found to decrease with increasing wavelength of light used in the experiments. The wide-angle X-ray diffraction analysis shows that the samples with relatively low orientation possess oriented non-crystalline array of chains whereas those with high molecular orientation possess well defined and oriented crystalline array of chains along the fiber axis direction. X-ray analysis showed increasing crystallite size trend with increasing molecular orientation. SEM images showed micro-cracks on low oriented fiber surfaces becoming smooth on highly oriented fiber surfaces. Excellent bending characteristics were observed with knotted fibers implying relatively easy fabric formation.

• 대한물리의학회지
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• 제3권2호
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• pp.127-133
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• 2008

Purpose : The purpose of this study was carried out to review the correlation between foot shape(supination foot, pronation foot) and low back pain, hip abduction muscle and ankle lateral sprain. Methods : By using internet, we research the PubMed, Science Direct, KISS, DBpia We selected the article between 1990 and 2007. Key words were supination foot, pronation foot, balance. Results : Normal control balance of human body needs a optimal anatomical alignment and function of musculoskeletal and central nerve system that control continuously to integrate. Especially ankle and foot complex play an important role in postural control because it is located distal part in human body. Supination foot brings to chronic ankle sprain or chronic ankle instability and range of motion limitation due to the weakness of lateral ankle muscle. Pronation foot brings to knee injury because of lower leg internal rotation force. Conclusion : Excessive supination and pronation foot happen to muscle imbalance. Especially weakness of hip abduction or injury of ankle lateral muscle or low back pain are due to abnormal balance and anatomical alignment.

• Macromolecular Research
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• 제15권6호
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• pp.506-512
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• 2007

2,3-Di-(2'-hydroxyethoxy)-4'-nitrostilbene (3) was prepared and condensed with terephthaloyl chloride, adipoyl chloride, and sebacoyl chloride to yield novel Y-type polyesters (4-6) containing the NLO-chromophores 2,3-dioxynitrostilbenyl groups, which constituted parts of the polymer backbones. Polymers 4-6 were soluble in common organic solvents such as acetone and N,N-dimethylformamide. Polymers 4-5 showed thermal stability up to $300^{\circ}C$ in thermogravimetric analysis with glass transition temperatures $(T_g)$, obtained from differential scanning calorimetry, in the range $81-95^{\circ}C$. The second harmonic generation (SHG) coefficients $(d_{33})$ of the poled polymer films at the 1064 nm fundamental wavelength were around $3.68{\times}10^{-9}$ esu. The dipole alignment exhibited high thermal stability up to $T_g$, and there was no SHG decay below $T_g$ due to the partial main-chain character of the polymer structure.