• Journal of Sensor Science and Technology
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• v.15 no.2
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• pp.148-152
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• 2006

This paper describes the fabrication of SiCN microstructures for super-high temperature MEMS using photopolymerization of pre-ceramic polymer. In this work, polysilazane liquide as a precursor was deposited on Si wafers by spin coating, microstructured and solidificated by UV lithography, and removed from the substrate. The resulting solid polymer microstructures were cross-linked under HIP process and pyrolyzed to form a ceramic of withstanding over $1400^{\circ}C$. Finally, the fabricated SiCN microstructures were annealed at $1400^{\circ}C$ in a nitrogen atmosphere. Mechanical characteristics of the SiCN microstructure with different fabrication process conditions were evaluated. The elastic modules, hardness and tensile strength of the SiC microstructure implemented under optimum process condtions are 94.5 GPa, 10.5 GPa and 11.7 N/min, respectively. Consequently, the SiCN microstructure proposed in this work is very suitable for super-high temperature MEMS application due to very simple fabrication process and the potential possiblity of sophisticated mulitlayer or 3D microstructures as well as its good mechanical properties.

• Journal of Powder Materials
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• v.23 no.1
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• pp.26-32
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• 2016

Powder injection molding (PIM), which combines the advantages of powder metallurgy and plastic injection molding technologies, has become one of the most efficient methods for the net-shape production of both metal and ceramic components. In this work, plasma display panel glass bodies are prepared by the PIM process. After sintering, the hot isostatic pressing (HIP) process is adopted for improving the density and mechanical properties of the PIMed glass bodies. The mechanical and thermal behaviors of the prepared specimens are analyzed through bending tests and dilatometric analysis, respectively. After HIPing, the flexural strength of the prepared glass body reaches up to 92.17 MPa, which is 1.273 and 2.178 times that of the fused glass body and PIMed bodies, respectively. Moreover, a thermal expansion coefficient of $7.816{\times}10^{-6}/^{\circ}C$ is obtained, which coincides with that of the raw glass powder ($7.5-8.0{\times}10^{-6}/^{\circ}C$), indicating that the glass body is fully densified after the HIP process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.392-393
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• 2006

This paper describes the fabrication of SiCN microstructures for super-high temperature MEMS using photopolymerization of pre-ceramic polymer. In this work. polysilazane liquide as a precursor was deposited on Si wafers by spin coating. microstructured and solidificated by UV lithography. and removed from the substrate. The resulting solid polymer microstructures were cross-linked under HIP process and pyrolyzed to form a ceramic of withstanding over $1400^{\circ}C$. Finally, the fabricated SiCN microstructures were annealed at $1400^{\circ}C$ in a nitrogen atmosphere. Mechanical characteristics of the SiCN microstructure with different fabrication process conditions were evaluated. The elastic modules. hardness and tensile strength of the SiC microstructure implemented under optimum process conditions are 94.5 GPa, 10.5 GPa and 11.7 N/min, respectively. Consequently, the SiCN microstructure proposed in this work is very suitable for super-high temperature MEMS application due to very simple fabrication process and the potential possiblity of sophisticated multlayer or 3D microstructures as well as its good mechanical properties.

• Hip & pelvis
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• v.34 no.1
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• pp.25-34
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• 2022

Purpose: Mortality rates following hip fracture surgery have been well-studied. This study was conducted to examine mortality rates in asymptomatic patients presenting for treatment of acute hip fractures with concurrent positive COVID-19(+) tests compared to those with negative COVID-19(-) tests. Materials and Methods: A total of 149 consecutive patients undergoing hip fracture surgery during the COVID-19 pandemic at two academic medical centers were reviewed retrospectively. Patients were divided into two groups for comparative analysis: one group included asymptomatic patients with COVID-19+ tests versus COVID-19- tests. The primary outcome was mortality at 30-days and 90-days. Results: COVID-19+ patients had a higher mortality rate than COVID-19- patients at 30-days (26.7% vs 6.0%, P=0.005) and 90-days (41.7% vs 17.2%, P=0.046) and trended towards an increased length of hospital stay (10.1±6.2 vs 6.8±3.8 days, P=0.06). COVID-19+ patients had more pre-existing respiratory disease (46.7% vs 11.2%, P=0.0002). Results of a Cox regression analysis showed an increased risk of mortality at 30-days and 90-days from COVID-19+ status alone without an increased risk of death in patients with pre-existing chronic respiratory disease. Conclusion: Factors including time to surgery, age, preexisting comorbidities, and postoperative ambulatory status have been proven to affect mortality and complications in hip fracture patients; however, a positive COVID-19 test result adds another variable to this process. Implementation of protocols that will promote prompt orthogeriatric assessments, expedite patient transfer, limit operating room traffic, and optimize anesthesia time can preserve the standard of care in this unique patient population.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.329-337
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• 2000

An investigation has been performed to develop an analysis tool based on a nonlinear beam theory, which can be used to predict the long-term behavior of an artificial hip joint. The nonlinear behav ior of the femur arise from the coupled dependence of the bone density and the mechanical properties on each other. The beam theory together with its numerical algorithm is developed to take into account the nonlinear bone remodeling process of the femur that is long enough to be assumed as a beam. A piecewise linear curve for the bone remodeling rate is used in the bone remodeling theory and the surface area density of bone is modeled as the third order polynomial function of bone density. At each section of the beam, a constant curvature is assumed and the longitudinal strains are also assumed to vary linearly across the section. The Newton-Rhapson iteration method is used to solve the nonlinear equations for each cross section of the bone and a backward method is used to march along the time. The density and the remodeling signal ar, calculated along with time for the various time steps, and the developed beam theory has been verified by comparing with the results of finite element analysis of a remodeling bone with an artificial hip joint of titanium prosthesis subjected to uni-axial loads and pure bending moment. It is concluded that the developed beam theory can be used to predict the long-term behavior of the femur and thus to design the artificial hip prosthesis.

• Journal of Sasang Constitutional Medicine
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• v.16 no.1
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• pp.100-111
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• 2004

Objectives To study on the relation between Sasang constitution and obesity and that of obese patient's clinical symptom. Methods The subjects were 129 female patients to visit to diet. The subjects were 129 female patients to diet who answered questionnaire QSCC II and were diagnosed by the Sasang constitution from May to December in 2001 at Nara oriental medical clinic. Results 1. Of obese patients 79.1% were Taeumin, 11.6% Soeumin, and 9.3% Soyangin. 2. A relation of a grade of obesity and Sasang constitution. 2-1) 45.8% of the obese patients were high level obesity who had over 35% of body fat. Out of these people, 91.5% were Taeumin. 2-2) 40.3% of the obese patients weight hip ratio was between 0.84 to 0.89 and 84.6% of these people were proved to be Taeumin. 2-3) 39.2% of the people who had a minimum weight hip ratio of 0.90 were significantly Taeumin, 6.7% Soeumin and 16.6% Soyangin. 2-4) 65.7% of Taeumin were obese patients. 3. Obesity treatment with constitution. 3-1) 59.8% of Taeumin were Pyo-zng patients. 3-2) As treatment periods tended to increase, Taeumin and Soeumin patients showed a large decling of body fat, whereas Soeumin patients showed the opposite reaction. 3-3) The weight hip ratio was led by Taeumin with 0.03 and then came Soeumin and Soyangin with a 0.02 ratio. As treatment was taken into process longer Taeumin patients showed a great progress in decreasing their weight hip ratios. 4. Costitutional related symptom with Obesity. 4-1) Taeumin was followed by Soyangin and then Soeumin in family history. 4-2) Soeumin was followed by Taeumin, then Soyangin when complain of physical fatigue was taken into consideration. 4-3) The ordinary exercise was led by Soyangin, Taeumin then Soeumin. 4-4) People who receive stress turned out to be 72.9% much higher than the people who don't. 4-5) Overeating due to stress was found in 83.3% of Soyangin.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.1
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• pp.95-105
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• 2024

PURPOSE: This study aimed to utilize the International Classification of Functioning, Disability, and Health (ICF) tool to identify a problem list and explore intervention effects using proprioceptive neuromuscular facilitation (PNF) for improving the crosswalk performance of patients who have undergone a bilateral hip arthroplasty. METHODS: The subject of this study was a 43-year-old male who had undergone a bilateral hip arthroplasty. To address the subject's functional status, a clinical decision-making process was carried out in the order of examination, evaluation, diagnosis, prognosis, intervention, and outcome. Patient information during the examination was collected using the ICF core set. The evaluation involved listing the items of each problem using the ICF assessment sheet and identifying the interaction between activity limitations and the impairment level. The diagnosis explicitly described the causal relationships derived from the evaluation using ICF terminology. The prognosis presented activity goals, body function, and structured goals in terms of the activity and participation levels that needed to be achieved for an individual's functional status. The intervention approached problems through the four components of the PNF philosophy, namely basic principles and procedures, techniques, and patterns, in an indirect-direct-task sequence. Results were compared before and after the intervention using the ICF evaluation display. RESULTS: The results of the study showed that the primary activity limitation, which was the walking time across the crosswalk, showed improvement, and the trunk's counter rotation and the weight-bearing capacity of both the lower limbs, which were impairment level indicators, were enhanced. CONCLUSION: This study suggests that PNF intervention strategies will serve as a positive approach for improving crosswalk walking in patients with bilateral hip arthroplasty.

• Journal of Korean Society of Neurocognitive Rehabilitation
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• v.10 no.2
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• pp.19-26
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• 2018

Many people do not realize that they have poor neck posture. Incorrect forward head posture can lead to turtle neck. This aim to development of specific chair to reduce tension and other symptoms of turtle neck posture. This turtle neck syndrome adjusting chair is a chair that supports the hip and shin of a person to help them correct their posture. It is consisted of the shin support that supports the shin in an angle and the hip support that supports one's hip while the shin is supported at an angle, the main frame that has the two of them connected and the fluid seat that is joined at the top of the hip support and reacts accordingly to the shape of the hip. This is a posture correction chair which has the fluid seat that provides unstable hip support so that it can allow a person to realize their posture from the constant stimulation about the posture. When one seats on the posture correction chair, their hip and shin are supported at an angle that straitens their back, and as their back is straightened, their shoulders and chest are opened, and the neck is positioned at the middle to help them correct their posture. An unbalanced posture causes discomfort to the person seated at the chair, and the person sitting on the posture correction chair will continuously adjust his/her posture to balance the hips to keep the correct posture. Through this process, the person shall adjust his/her left and right posture, ultimately increasing the effectiveness of posture correction. A future collective study on the continuous posture correction of people having turtle neck syndrome using this posture correction chair is required.

• Journal of Powder Materials
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• v.23 no.1
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• pp.15-20
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• 2016

Niobium is one of the most important and rarest metals, and is used in the electronic and energy industries. However, it's extremely high melting point and oxygen affinity limits the manufacture of Nb coating materials. Here, a Nb coating material is manufactured using a kinetic spray process followed by hot isotactic pressing to improve its properties. OM (optical microscope), XRD (X-ray diffraction), SEM (scanning electron microscopy), and Vickers hardness and EPMA (electron probe micro analyzer) tests are employed to investigate the macroscopic properties of the manufactured Nb materials. The powder used to manufacture the material has angular-shaped particles with an average particle size of $23.8{\mu}m$. The porosity and hardness of the manufactured Nb material are 0.18% and 221 Hv, respectively. Additional HIP is applied to the manufactured Nb material for 4 h under an Ar atmosphere after which the porosity decreases to 0.08% and the hardness increases to 253 Hv. Phase analysis after the HIP shows the presence of only pure Nb. The study also discusses the possibility of using the manufactured Nb material as a sputtering target.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.307-318
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• 2013

The purpose of this study was to analyze the kinematic variables of glide kip motion on the uneven bars through a two-dimensional cinematography. Three expert female gymnastics players were involved in the data gathering process. The followings were concluded according to the results. The arm, trunk and leg segments were fully extended throughout the kip movement. The whole body center of gravity showed the biggest changes during 66 to 87% of the kip motion. During the kip phase, the horizontal displacement of the leg was greater than the vertical displacement the leg. Glide kip motion should be done in orders of upward movement of leg, forward movement of leg, upward movement of trunk and forward movement of trunk segment. It was found that trunk segment and hip joint movements showed bigger changes than those of leg segment and shoulder joint in the glide kip motion. The largest angular velocity of hip joint was shown in the middle of the kip Phase. In conclusion, effective kip movement could be resulted when the trunk was displaced posterior-upward direction with fast hip joint extension after the leg segment was elevated upward and thrusted forward in advance.