• 한국운동역학회지
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• 제27권4호
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• pp.279-285
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• 2017

Objective: The purpose of this study was to perform a muscle function path analysis of muscle function on myofascial meridians. Method: Seven male students (mean age: $22{\pm}3.46years$; mean mass: $72.71{\pm}8.19kg$; mean height: $174{\pm}4.39cm$) without a history of musculoskeletal system symptoms or injuries were recruited for this study. The measurement muscle of the myofascial line was selected along with the muscle presented in "anatomy trains (Thomas W. Myers. 2014)", and the attachment of the surface EMG (Telemyo 2400T G2, USA) pad was determined according to "EMG analysis (Kim Tae Wan et al., 2013)". The subjects underwent maximum volumetric contraction of their fascia line end muscles three times in lying and standing postures and were subjected to the maximum number of contractions of the myofascial line muscle three times in the lying and standing postures. The sampling rate of the EMG signal was set to 1,000 Hz, and the bandwidth was 20 to 350 Hz. The activity of each muscle was quantitated using the Pearson correlation coefficient, and SPSS 22.0 was used for data analysis. Results: In myofascial meridians, a positive correlation in the myofascial connection and a negative correlation in the mechanical connection were observed. Conclusion: Muscles that show significant contract correlations with one another may be expected to be used as an effective clinical marker in muscle strengthening or relaxation therapy, and rehabilitative training. In this study, the correlation of total myofascial meridians may differ without consideration of functional posture. Future studies need to consider these points.

• The Journal of Korean Physical Therapy
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• 제31권6호
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• pp.333-338
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• 2019

Purpose: Although previous studies on the screw-home movement (SHM) for autopsy specimen and walking of living persons conducted, the possibility of acquiring SHM based on inertial measurement units received little attention. This study aimed to investigate the possibility of measuring SHM for the non-weighted bearing using a micro-electro-mechanical system-based wearable motion capture system (MEMSS). Methods: MEMSS and camera-based motion analysis systems were used to obtain kinematic data of the knee joint. The knee joint moved from the flexion position to a fully extended position and then back to the start point. The coefficient of multiple correlation and the difference in the range of motion were used to assess the waveform similarity in the movement measured by two measurement systems. Results: The waveform similarity in the sagittal plane was excellent and the in the transverse plane was good. Significant differences were found in the sagittal plane between the two systems (p<0.05). However, there was no significant difference in the transverse plane between the two systems (p>0.05). Conclusion: The SHM during the passive motion without muscle contraction in the non-weighted bearing appeared in the entire range. We thought that the MEMSS could be easily applied to the acquisition of biomechanical data on the knee related to physical therapy.

• Wind and Structures
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• 제14권4호
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• pp.285-300
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• 2011

Researchers at the International Hurricane Research Center (IHRC), Florida International University (FIU), are working in stages on the construction of a large state-of-the-art Wall of Wind (WoW) facility to support research in the area of Wind Engineering. In this paper, the challenges of simulating hurricane winds for the WoW are presented and investigated based on a scale model study. Three wind profiles were simulated using airfoils, and/or adjustable planks mechanism with and without grids. Evaluations of flow characteristics were performed in order to enhance the WoW's flow simulation capabilities. Characteristics of the simulated wind fields are compared to the results obtained from a study using computational fluid dynamics (CFD) and also validated via pressure measurements on small-scale models of the Silsoe cube building. Optimal scale of the test model and its optimal distance from the WoW contraction exit are determined - which are two important aspects for testing using an open jet facility such as the WoW. The main objective of this study is to further the understanding of the WoW capabilities and the characteristics of its test section by means of intensive tests and validations at small scale in order to apply this knowledge to the design of the full-scale WoW and for future wind engineering testing.

• 한국세라믹학회지
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• 제40권3호
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• pp.317-321
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• 2003

The grain-boundary microcracking materials in the system A1$_2$Ti $O_{5}$ -ZrTi $O_4$(ZAT) is influenced by the thermal expansion anisotropy. The range of ZAT compositions investigated had showed very low thermal expansions of 0.3~1.3$\times$10$^{-6}$K compared to 8.29$\times$10$^{-6}$K of pure ZrTi $O_4$and 0.68$\times$10$^{-6}$K of polycrystalline A1$_2$Ti $O_{5}$ , respectively, compared with the theoretical thermal expansion coefficient for a single crystal of A1$_2$Ti $O_{5}$ , 9.70$\times$10$^{-6}$K. The low thermal expansion and microcraking temperature are apparently due to a combination of thermal contraction and expansion caused by the large thermal expansion anisotropy of the crystal axes of the A1$_2$Ti $O_{5}$ phase.

• 여성건강간호학회지
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• 제25권3호
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• pp.239-257
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• 2019

Purpose: To analyze the job of nursing unit managers working at women's hospital, using DACUM (developing a curriculum), DACUM is a method for analyzing job-focused competency. Methods: This study involved a descriptive survey. A DACUM workshop was held to define women's hospital nursing unit managers' role and identify their duties and tasks. For the workshop, a committee was formed consisting of 5 women's hospital nursing unit managers. Finally, after validation, the developed contents were made into a survey asking about nursing unit manager's duties and tasks. Results: Sixteen duties and 83 tasks were identified on the DACUM chart. The importance, difficulty, and frequency of the tasks were ranked in terms of A, B, and C, with A being the highest degree. Eight tasks received A's all in importance, difficulty, and frequency of performance. The 8 tasks were: 'taking over', 'taking care of seriously ill patients on handover', 'ward rounding', 'analyzing and resolving demands identified during handover and patient tour', 'reporting patient status during rounding', 'promoting breast-feeding', 'uterine contraction, and training for breast-feeding'. The duty with the biggest determinant coefficient (DC) was 'patients complaint management' (DC=7.09). Based on tasks, the one with the biggest DC was 'solving patient and patient guardian's complaints' (DC=7.53), followed by 'making infection control guidelines' (DC=7.5). Conclusion: When expanding the nursing staff of the hospital, women's hospitals nursing unit managers also need to use administrative functions as intermediaries to focus on the operation management of the entire hospital rather than direct nursing to suit their role.

• 대한의용생체공학회:의공학회지
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• 제44권5호
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• pp.336-345
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• 2023

The present study was designed to evaluate changes in neuromuscular properties and the structural and qualitative characteristics of muscles during submaximal isometric contractions at low-to-relatively vigorous target forces and to determine their influence on force steadiness (FS). Thirteen young adult males performed submaximal isometric knee extensions at 10, 20, 50, and 70% of their maximal voluntary isometric contraction using their non-dominant legs. During submaximal contractions, we recorded force, EMG signals from vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF), and ultrasound images from the distal RF (dRF). Force and EMG standard deviation (SD) and coefficient of variation (CV) values were used to measure FS and EMG steadiness, respectively. Muscle thickness (MT), pennation angle (PA), echo intensity (EI), and texture features were calculated from ultrasound images to assess the structural and qualitative characteristics of the muscle. FS, neuromuscular properties, and texture features showed significant differences across different force levels. Additionally, there were significant differences in EMG_CV among the quadriceps at the 50% and 70% force levels. The results of correlation analysis revealed that FS had a significant relationship with EMG_CV in VM, VL, and RF, as well as with the texture features of dRF. This study's findings demonstrate that EMG steadiness and texture features are influenced by the magnitude of the target force and are closely related to FS, indicating their potential contribution to force output control.

• Journal of Oral Medicine and Pain
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• 제30권1호
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• pp.45-55
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• 2005

오른손잡이와 왼손잡이가 있듯이 저작도 주로 사용하는 쪽이 있는 편측저작습관자와 양쪽을 다 사용하는 비편측저작자가 있다. 본 연구는 1년 이상 지속된 편측저작습관이 저작근과 턱관절에 미치는 영향을 알아보고자, 연세대학교 치과대학 재학생 및 치과병원 교직원 중 참여하기를 희망하는 편측저작습관자 46명, 비편측저작습관자 36명, 총 82명의 지원자를 대상으로 저작근의 근활성도와 교합력을 검사하여 다음과 같은 결과를 얻었다. 연구에 앞서 설문 및 임상검사를 통하여 연구에 영향을 끼칠 수 있는 특기할 전신병력이나 불규칙한 치열 및 비정상적인 교합을 가진 자는 배제하였다. 1. 편측저작습관자군에서 안정위와 최대 이악물기(maximal voluntry contraction; MVC)상태에서의 저작측과 비저작측간 근활성도는 차이를 나타내지 않았다 (p>0.05). 2. 안정위 시 전측두근과 교근에서의 근활성도 비대칭 지수는 편측저작습관자군과 비편측저작습관자군 사이에 차이를 나타내지 않았다(p>0.05). 3. 최대 이악물기 시 교근의 근활성도 비대칭 지수는 편측저작습관자군에서 비편측저작습관자군 보다 높게 나타났으며 (p<0.05), 전측두근의 근활성도 비대칭 지수는 편측저작습관자군과 비편측저작습관자군간에 차이를 나타내지 않았다(p>0.05). 4. 편측저작습관자군에서 저작측과 비저작측간의 평균교합력과 교합접촉면적은 차이를 나타내지 않았다(p>0.05). 5. 편측저작습관자군과 비편측저작습관자군간의 평균교합력의 비대칭 지수와 교합접촉면적의 비대칭 지수는 차이를 나타내지 않았다(p>0.05). 이상의 연구결과 편측저작습관은 저작근의 근활성도와 평균교합력 및 교합접촉면적에 영향을 미쳐 변화를 일으키기 보다는, 정상적인 기능을 하는 생리적 비대칭이라고 보는 것이 타당하다고 생각한다. 향후 연구 시 편측저작자와 비편측저작자를 구분하기위한 객관적인 기준의 제시가 필요하다고 생각한다.

• 센서학회지
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• 제17권2호
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• pp.133-142
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• 2008

Respiration is induced by muscular contraction of the chest and abdomen, resulting in the abdominal volume change. Thus, continuous measurement of the abdominal dimension enables to monitor breathing activity. Conductive rubber cord has been previously introduced and tested to develop wearable application for respiratory measurements. The present study implemented wireless wearable respiratory monitoring system with the conductive rubber cord in the patient's pants. Signal extraction circuitry was developed to obtain the abdominal circumference changes reflecting the lung volume variation caused by respiratory activity. Wireless transmission was followed based on the zigbee communication protocol in a size of 65mm${\times}$105mm easily put in pocket. Successful wireless monitoring of respiration was performed in that breathing frequency was accurately estimated as well as different breathing patterns were easily recognized from the abdominal signal. $CO_2$ inhalation experiment was additionally performed in purpose of quantitative estimation of tidal volume. Air mixed with $0{\sim}5%\;CO_2$was inhaled by 4 normal males and the respiratory air flow rate, abdominal dimension change, and end tidal $CO_2$ concentration were simultaneously measured in steady state. $CO_2$ inhalation increased the tidal volume in normal physiological state with a correlation coefficient of 0.90 between the tidal volume and the end tidal $CO_2$ concentration. The tidal volume estimated from the abdominal signal linearly correlated with the accurate tidal volume measured by pneumotachometer with a correlation coefficient of 0.88 with mean relative error of approximately 8%. Therefore, the tidal volume was accurately estimated by measuring the abdominal dimension change.

• 한국정밀공학회지
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• 제30권3호
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• pp.271-277
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• 2013

Inconel 718 super alloy was aging heat treated at the temperature range from $675^{\circ}C$ to $785^{\circ}C$ for 5~40 hours after solution annealing at $1025^{\circ}C$ for 1 hour. The aging treated specimens were investigated microstructure, mechanical properties and thermal expansion/contraction. Precipitates appeared for a long time aging treatment were niobium carbide and also ${\gamma}^{\prime}$ phase. For the aging treatment time of 10 hours, the changes in strength and hardness with increasing aging treatment temperature showed the maximum value at the temperature of $725^{\circ}C$. This maximum value is to be related with the precipitation of ${\gamma}^{\prime}$ and ${\gamma}^{{\prime}{\prime}}$ phases. The decrease in strength, elongation and hardness during long time aging at $725^{\circ}C$ were thought to be induced from the coarsening of the grain size and the transformation of ${\gamma}^{{\prime}{\prime}}$ phase to ${\gamma}^{\prime}$ phase. For the specimens treated for 10 hours, impact energy showed constant value of ~105 J with increasing the aging temperature, however this value continuously decreased with elapsing time at the aging temperature of $725^{\circ}C$. It was found that the decrease in impact value was induced from the coarsening of grain size and the carbide coarsening. The coefficient of thermal expansion of aging treated Inconel 718 alloy increased with raising test temperature, and the coefficient was appeared $11.57{\sim}12.09{\mu}m/m{\cdot}^{\circ}C$ and $14.28{\sim}14.39{\mu}m/m{\cdot}^{\circ}C$, respectively, after heating to $150^{\circ}C$ and $450^{\circ}C$.

• The Korean Journal of Physiology
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• 제23권2호
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• pp.263-275
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• 1989

Mechanical contractions and electrical activities of the fundic longitudinal and antral circular muscle fibers were investigated in order to elucidate topical differences of gastric motility. K-induced contracture was produced by exposure of muscle strips to high K Tyrode solution. Membrane potential and mechanical contraction were simultaneously recorded by conventional glass microelectrode method and single sucrose-gap technique. All experiments were performed in tris-buffered Tyrode solution which was aerated with $100%\;O_2\;and\;kept\;35^{\circ}C$. The results obtained were as follows: 1) The resting membrane potential of circular muscle cells in the antral region was about 10 mV more negative than that in the fundic region. 2) The membrane potentials decreased almost linearly as the extracellular KCI concentration was increased both in antral circular muscle cells and in fundic longitudinal muscle cells. 3) The thresholdal K concentration of K-contracture was 15 mM (membrane potential, -48 mV) for the antral circular muscle strip and 20 mM for the fundic longitudinal muscle cells. 4) The ratio of membrane permeability coefficient for $Na^+\;and\;K^+,\;P_{Na}/P_K\;({\alpha})$ was 0.065 for antral circular muscle cells and was 0.108 for fundic longitudinal muscle cells. 5) K-contracture of antral and fundic smooth muscle strips showed the contracture composed of phasic and tonic components. The amplitude of the phasic component increased sigmoidally in a dose-dependent manner, whereas that of the tonic component was maximal at a concentration of 40 mM KCI and at the concentrations above or below 40 mM KCI the amplitude was reduced. 6) The inverse relationship between the amplitude of tonic component and extracellular KCI concentration in the range of 40 to 150 mM KCI was more prominent in the antral circular muscle strip than in the fundic longitudinal muscle strip, where the amplitude of the tonic component decreased less steeply and was maintained higher at the same high K concentrations. 7) The tonic component was totally dependent on the external $Ca^{2+}$ and completely abolished by verapamil, while tile phasic component was far less dependent on the external $Ca^{2+}$ and partially suppressed by verapamil. From the above results, the following conclusions could be made. 1) The phasic component of K-contracture is produced both by intracellular $Ca^{2+}$ mobilization and by $Ca^{2+}$-influx from outside, while the tonic component is generated and maintained by the $Ca^{2+}-influx$ through the potential-dependent $Ca^{2+}$ channel. 2) The mechanism of reducing the free $Ca^{2+}$ concentration in the myoplasm seems to be more developed in the antral circular muscle than in the fundic longitudinal muscle. 3) The lower resting membrane potential of the fundic longitudinal muscle cell reflects a relatively high $P_{Na}/P_K$ ratio of about 0.108.