본 연구는 최근 7년간 Google scholar, ProQuest에서 Adolescent Idiopathic Scoliosis(AIS), Cobb’s angle, Surgical, Conservative, In tervention을 핵심 키워드로 활용하여 청소년 특발성 척추측만증의 수술 적 중재 방법과 보존적 중재 방법이 Cobb’s angle에 미치는 영향을 조 사하였다. 중재 전ㆍ후 Cobb’s angle 차이를 JAMOVI를 이용하여 메타 회귀분석을 실시하였으며 청소년 특발성 척추측만증 환자에게 Cobb’s an gle 긍정적 변화에 효과적인 중재 방법은 수술적 중재 방법에는 Selectiv e thoracic fusion, Posterior spinal fusion, Anterior spinal fusion 이 있었으며, 보존적 중재 방법에는 Lumbar cheneau brace, Xinmiao treatment system(XTS), Cheneau brace+Schroth best practice(S BP), Core stabilization exercises가 있음을 확인하였다. 이러한 연구 결과를 통하여 청소년 특발성 척추측만증 연구 분야의 방향성 제공에 도 움을 주고 향후 어떠한 중재 방법이 효과적일지 판단할 수 있는 지표개발 을 요구하는 바이다.
Hydraulic turbines can convert tidal current energy into electric energy, and the addition of a deflector cover to the turbine can improve the efficiency of the turbine's energy harvesting. The angle of the inlet section and the angle of the outlet section of the deflector will further affect the final energy-acquisition efficiency.A threedimensional numerical model for turbine flow field analysis is established, and the RNG k-ε turbulence model is selected by CFD method, and the best angles of inlet section and outlet section are analysed by the method of sliding mesh to obtain the best angle of inlet section and outlet section separately, and then three groups of angles are selected near the best angle of inlet section and outlet section to make orthogonal comparisons. The energy acquisition efficiency of the turbine is calculated at different angles of the inlet and outlet sections of the deflector, and the turbine streamline distribution, velocity and pressure maps are analysed with and without the deflector.The study shows that the deflector can play the role of convergence of the downstream flow, which can improve the efficiency of the turbine energy acquisition, and the maximum energy acquisition efficiency is at the inlet angle of 29° and the outlet angle of 40 °, and the maximum energy acquisition efficiency can be improved by about 32 percent.
WAAM(Wire Arc Additive Manufacturing) has gained attention as an innovative technology in small-batch, multi-product production due to its advantages of low production costs, rapid build rates, and design flexibility. However, challenges such as relatively low geometric accuracy, surface finish defects, residual stresses, and distortion due to high heat input persist and require improvement. This study analyzes the influence of deposition path angles on deposition performance in the WAAM process. Experiments were conducted using stainless steel (STS309MoL) wire, known for its excellent heat resistance and corrosion resistance due to its relatively high ferrite content within the austenitic structure. To mitigate residual stresses and distortion caused by high heat input, the CMT(Cold Metal Transfer) process was employed for five layers of deposition. Five different deposition path angles were selected as process variables, and the impact of deposition path angles on deposition performance was evaluated based on experimental results.
In the past, aviation technology developed from wood to alloys to composite materials. Propellers have also evolved from wood to composite materials for modern small aircraft. In this context, research is needed on a three-blade composite propeller based on the Rotax 912 engine, which is widely used in Korea. In this study, the goal is to select the optimal propeller pitch angle by investigating noise changes according to changes in blade angle and engine 4000RPM of three types of three-blade propellers different from each propeller manufacturer. By comparing the noise of the three types of propellers most commonly used in Korea and suggesting the minimum noise blade angle for each propeller, we aim to help aircraft operators select propellers and resolve noise complaints around airfields.
초대형 자동차운반선(LCTC)의 높이는 선저에서 조타실까지 약 44~46m에 이르며, 자동차운반선이 대형화될수록 상부 무게가 하부 무게보다 무거운 중두선의 특징을 가진다. 이 연구는 선회 중 전도한 자동차운반선 골든 레이호(G호)의 최대 외방경사각을 추정하 여 사고 원인 규명과 유사사고 방지에 목적이 있다. 이론식으로 계산된 최대 외방경사각은 GM이 +3.0m 이상 상황에서 7.5°(19kn, 타각 35°), GM이 +1.85m인 상황에서 16.7°였다. 실험에 의한 수정식으로 계산한 최대 외방경사각은 GM이 +3.0m 이상 상황에서 10.5°(19kn, 타각 35°), GM이 +1.85m인 상황에서 23.3°를 보였다. G호는 전도사고 당시 도선사의 지시에 따라 속력 13kn, 우현 타각(10°→20°)을 사용하여 침 로 038°(T)에서 105°(T)로 변침 중이었다. 이 때 최대 외방경사각은 좌현으로 7.8° 내지 10.9°로 추정된다. 평상 시 외방경사각보다 2.2배 높 은 수치이다. 화물선의 최소 GoM은 IS coded에서 +0.15m 이상을 요구하고 있다. 전도된 G호도 +1.72m GoM을 확보하고 있었다. GoM에 대 한 기준 미달이 전도의 원인이 아니라, 선회 중 횡경사 모멘트에 대응할 수 있는 충분한 GoM을 확보하지 않아 전도된 것이다. 이 연구는 중앙해양안전심판원과 USCG의 사고 조사 결과를 뒷받침한다.
본 연구의 목적은 기존의 하드 타입의 관성 센서를 대체할 수 있는 소프트 원단 기반 팔꿈치 굽힘 각 센서를 개발하 고, 이를 이용하여 굽힘 각도를 추정하는 시스템을 개발하는 것이다. 본 연구에서는 비교 선정을 위하여 Bergamo, E-band, Span cushion, Polyester의 서로 다른 역학적 특성을 가진 4종류 원단에 SWCNT (Single-Walled Carbon Nanotubes) 함침을 통해 전도성을 부여한 후 성능 평가를 통하여 하나의 원단을 선정하여 팔꿈치 굽힘 각 센서로 제작 하였다. 성능을 평가하는 지표로 게이지율(Gauge factor), 이력현상(Hysteresis) 및 센싱 범위를 사용하였다. 제작된 센 서를 통해 얻은 데이터는 bending 동작에서의 각도에 대한 센서 출력값의 변화와 extending 동작에서의 각도에 대한 센서 출력값의 변화가 다른 경향을 갖고 있기 때문에 두 가지 동작을 나누는 것을 1-step으로 하였다. 2-step으로, 데이 터의 복잡한 비선형 관계를 처리하고 높은 데이터 정확도를 달성하기 위해 MLP (Multi-Layer Perceptron)를 활용하였 다. 따라서 소프트 텍스타일 굽힘 센서를 제작하였고, MLP를 통해 비선형 관계를 처리하고 각도 추정이 가능해졌다. 본 연구 결과를 기반으로 다양한 스마트 웨어러블 및 헬스케어 분야에서 효과적으로 활용되기를 기대한다.
Background: The forward head posture acts as a factor that can cause various neurovascular and musculoskeletal dysfunctions. But searching for a study on quality of life for patient with forward head posture was challenging. Therefore, this study aims to find the factors that most affect the quality of life in patients with forward head posture. Objectives: The purpose of this study was to investigate the correlations between the cranio-vertebral angle (CVA), neck disability index (NDI), pain, and sternocleidomastoid (SCM) thickness of patients with forward head posture and the quality of life of the patients and to figure out important factors that affect the quality of life of the patients with forward head posture. Design: Cress-sectional study. Methods: To measure the CVA, the angle at which the visible protrusion of C7 and the ear bead were connected was measured, and the neck disorder index was evaluated using the Korean version of NDI. The degree of pain of the subject was measured using a visual-analog scale (VAS). The SCM thickness was measured using an ultrasound imaging device, and the quality of life was evaluated using the Korean version of the World Health Organization quality of life questionnaire (WHOQL-BREF). Results: A significant predictive model showing 88% explanatory power for the dependent variable was confirmed, with an appropriate regression equation being found. The factor that most affected patients' quality of life in the forward head posture was confirmed by the SCM thickness. Conclusion: When applying an intervention to improve a patient's quality of life for patient with forward head posture, an intervention method that improves the SCM thickness should be recommended.
Forward head posture (FHP) is a musculoskeletal disorder that causes neck pain. Several exercise interventions have been used in South Korea to improve craniovertebral angle (CVA) and relieve neck pain. There has been no domestic literature review study over the past 5 years that has investigated trends and effects of exercise intervention methods for CVA with neck pain. This domestic literature review aimed to evaluate the trends and effects of exercise interventions on CVA and neck pain in persons with FHP. A review of domestic literature published in Korean or English language between 2018 and 2022 was performed. Literature search was conducted on Google Scholar and Korea Citation Index by using the following keywords: “exercise,” “exercise therapy,” “exercise program,” “forward head posture,” and “neck pain.” Ten studies were included in this review. All of the studies showed positive improvements after intervention programs that included exercises. Notably, four of these studies demonstrated significant differences in results between the experimental and control groups. Among the 10 studies, nine measured visual analogue scale or numerical rating scale scores and reported significant reductions in pain following interventions, including exercise programs. Five of these studies showed significant differences in results between the experimental and control groups. Furthermore, six studies that used neck disability index exhibited a significant decrease in symptoms after implementing intervention programs that included exercise, and significant differences in results were found between the experimental and control groups. This domestic literature review provides consistent evidence to support the application of various exercise intervention programs to improve CVA and relieve neck pain from FHP. Further studies are warranted to review the effects of various exercise interventions on FHP reported not only in domestic but also in international literature.
With the mandatory implementation of ESC for trucks starting in 2023, domestic truck manufacturers in South Korea are advocating for a relaxation of the maximum safe slope angle to achieve cost savings. However, there is a lack of research on the dynamic safety of trucks based on ESC installation and the relaxation of the maximum safe slope angle. This study evaluates the relationship between static safety factor (SSF) and the maximum safe slope angle, analyzing the dynamic stability of trucks through simulation considering various experimental variables. The results quantitatively demonstrate the impact of relaxing the maximum safe slope angle on dynamic safety and provide recommendations for future safety regulations.
In this study, a high-resolution integrated real-time visualization device using surface plasmon resonance was designed and considered to overcome the measurement limitations of existing optical systems. For precise measurements, resonance angle and reflectivity were calculated using theoretical equations, and the designed surface plasmon resonance visualization system was verified by comparison with experimental values using a He-Ne laser. Surface information of the droplet was acquired using polarized, single-wavelength converted white light, and quantified through image processing. As a result of the experiment, it was confirmed that when light with a wavelength of 632.8 nm is incident on the Kretchmann structure prism-metal thin film-dielectric (air/water), it is not totally reflected at an angle above the critical angle and the reflectivity is rapidly reduced due to the surface plasmon resonance phenomenon. As a result of quantifying the image, it was confirmed that the droplet reflectivity was similar to the theoretical reflectivity at each resonance angle.
Prepreg is an abbreviation of Preimpregnated Materials. It is a sheet-type product in which a matrix is impregnated with reinforced fiber. The prepreg has very different properties depending on the orientation of the fibers and the weaving method, and the orientation of the fibers plays an important role in determining the mechanical strength of CFRP. Short and randomly oriented reinforcing fibers show isotropy, while long, unidirectional reinforcing fibers exhibit anisotropic behavior and are strongest when the applied load is parallel to the reinforcing fibers. Classification by the direction of the fiber is divided into unidirectional, orthogonal, multiaxial, and the like. Uni-directional refers to a state in which almost all fibers in the fabric are aligned in one direction. When the fibers used as reinforcing materials are aligned in one direction, the fibers are used in a straight line without twisting during the fabric production process, and there is an advantage in that the amount of fibers used as a whole can be minimized. A uni-directional prepreg exhibits different cutting forces depending on the stacking orientation angle. In this experiment, the optimal cutting conditions for a uni-directional prepreg 45 degree orientation angle specimen are presented.
도스토옙스키는 백치를 통해 가장 아름다운 사람을 그리고자 했다. 그가 생각하는 아름다운 사람은 바로 예수 그리스도이다. 특히 그 그리스도 이미지는 신약성서 요한복음에 기초하고 있다. 도스토옙스키는 실제 요한복음을 깊이 읽으며 그 내용을 자신의 문학 작품 속에 다양한 방식으로 인용하고 반영했다. 그러한 경향은 백치에서도 마찬가지인데 아름다운 그리스도를 묘사하기 위해 므이쉬킨이라는 주인공을 설정하고 요한복음의 그리스도 이미지를 그에게 부여한다. 요한복음을 토대로 백치에서 강조되는 특징들은 다음과 같다: (1) 성육신, (2) 유로디비 및 사랑, (3) 거듭남과 변화, 부활, 그리고 이로 인한 영생. 강생의 소설 백치는 주인공 므이쉬킨을 통해 강생한 그리스도를 형상화한다. 물론 므이쉬킨은 때로 유로디비의 모습을 보이기도 하지만 저자는 이를 통해 요한의 예수와 마찬가지로 현실을 초월하는 아름다움을 그려낸다. 이처럼 도스토옙스키가 요한복음을 읽고 해석하여 자신의 작품에 투영한 내용을 토대로, 독자들은 요한복음을 새롭게 읽는 통찰력을 얻게 된다. 요한복음은 거듭남과 변화의 책이며, 이를 통한 영생을 추구하는 책이다.
본 연구는 최근 10년간 국내 청소년 특발성 척추측만증 보존적 중재법이 Cobb's angle의 변화에 어떠한 영향을 미치는지 알아보기 위하여 RISS(학술연구정 보서비스)에서 청소년 척추측만증, 특발성, 중재법을 핵심키워드로 검색하여 메타 회귀분석을 실시하였다. KCI등재후보지 이상 학술지만 선별하였으며, 참가자의 연 령 및 중재방법 등을 고려하여 총 11개의 논문이 선정되었다. 총 23개의 보존적 중재법은 크게 능동적 운동치료, 수동적 치료, 복합치료, 보조기로 나뉘었으며 신 뢰도95%에 해당하는 중재법은 능동적 운동치료 5가지와 보조기 1가지였다. 이는 능동적 운동치료의 형태의 보존적 중재법이 청소년 특발성 척추측만증 Cobb's angle변화에 가장 긍정적인 영향을 미치는 것으로 조사되었다.
The Wide-Angle Polarimetric Camera (PolCam) is installed on the Korea’s lunar orbiter, Danuri, which launched on August 5, 2022. The mission objectives of PolCam are to construct photometric maps at a wavelength of 336 nm and polarization maps at 461 and 748 nm, with a phase angle range of 0◦–135◦ and a spatial resolution of less than 100 m. PolCam is an imager using the push-broom method and has two cameras, Cam 1 and Cam 2, with a viewing angle of 45◦ to the right and left of the spacecraft’s direction of orbit. We conducted performance tests in a laboratory setting before installing PolCam’s flight model on the spacecraft. We analyzed the CCD’s dark current, flat-field frame, spot size, and light flux. The dark current was obtained during thermal / vacuum test with various temperatures and the flat-field frame data was also obtained with an integrating sphere and tungsten light bulb. We describe the calibration method and results in this study.
The Crab nebula is widely used as a polarization angle calibrator for single-dish radio observations because of its brightness, high degree of linear polarization, and well-known polarization angle over a wide frequency range. However, the Crab nebula cannot be directly used as a polarization angle calibrator for single-dish observations with the Korean VLBI Network (KVN), because the beam size of the telescopes is smaller than the size of the nebula. To determine the polarization angle of the Crab nebula as seen by KVN, we use 3C 286, a compact polarized extragalactic radio source whose polarization angle is well-known, as a reference target. We observed both the Crab nebula and 3C 286 with the KVN from 2017 to 2021 and find that the polarization angles at the total intensity peak of the Crab nebula (equatorial coordinates (J2000) R.A. = 05h34m32.3804s and Dec = 22◦00′44.0982′′) are 154.2◦ ±0.3◦, 151.0◦ ±0.2◦, 150.0◦ ±1.0◦, and 151.3◦ ±1.1◦ at 22, 43, 86, and 94 GHz, respectively. We also find that the polarization angles at the pulsar position (RA = 05h34m31.971s and Dec = 22◦00′52.06′′) are 154.4◦ ±0.4◦, 150.7◦ ±0.4◦, and 149.0◦ ± 1.0◦ for the KVN at 22, 43, and 86 GHz. At 129 GHz, we suggest to use the values 149.0◦ ± 1.6◦ at the total intensity peak and 150.2◦ ± 2.0◦ at the pulsar position obtained with the Institute for Radio Astronomy in the Millimeter Range (IRAM) 30-meter Telescope. Based on our study, both positions within the Crab nebula can be used as polarization angle calibrators for the KVN single-dish observations.
Most domestic pilots are trained at local airfields using propeller aircraft. Training aircraft are mainly trained in the airspace around the aerodrome, and mainly take-off and landing exercises that require a lot of practice among flight control skills. Aircraft noise is a sound that humans do not want. In this study, based on the Rotax 914 engine used in Korea, the propeller blade angle was changed by 1 degree for the 3-leaf “K company” propeller and the 3-leaf GSC wooden propeller, and the engine RPM was changed to examine the noise and thrust changes. The purpose of this study is to check whether noise and thrust loss are the least at the engine's maximum RPM, and to propose an aircraft operation plan in the noisy aerodrome area based on the values.
Ion-beam irradiation(IB) on HfO2 surface induced high-performance liquidcrystal(LC) driving at a 1-V threshold with vertical alignment of liquid crystals(LC). The high-k materials Atomic layer deposition was used to obtain LC orientation on ultra thin and high-quality films of HfO2 layers. To analyze surface morphological transition of HfO2 which can act as physic alignment effect of LC, atomic force micro scopy images are employed with various IB intensities. The contact angle was measured to elucidate the mechanism of vertical alignment of LC on HfO2 with IB irradiation. Contact angle measurements show the surface energy changes via IB intensity increasing.
In this work, the ablation behavior of monolith ZrB2-30 vol%SiC (Z30S) composites were studied under various oxy-acetylene flame angles. Typical oxidized microstructures (SiO2/SiC-depleted/ZrB2-SiC) were observed when the flame to Z30S was arranged vertically. However, formation of the outmost glassy SiO2 layer was hindered when the Z30S was tilted. The SiC-depleted region was fully exposed to air with reduced thickness when highly tilted. Traces of the ablated and island type SiO2 were observed at intermediate flame angles, which clearly verified the effect of flame angle on the ablation of the SiO2 layer. Furthermore, the observed maximum surface temperature of the Z30S gradually increased up to 2,200 °C proving that surface amorphous silica was continuously removed while monoclinic ZrO2 phase began to be exposed. A proposed ablation mechanism with respect to flame angles is discussed. This observation is expected to contribute to the design of complex-shaped UHTC applications for hypersonic vehicles and re-entry projectiles.