• 한국소음진동공학회논문집
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• 제19권1호
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• pp.85-93
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• 2009

There are many curves in Seoul subway system. Therefore, the noise from subway system in curved line gives displeasure to passenger. The subway noise in curved line is affected not only by rail condition but also wheel condition and dynamic characteristics. The railway curving noise can be divided into 2 categories. The first is the noise due to stick-slip between wheel tread and rail head, and the second is one by wheel flange contact on rail side. Because of these phenomena - stick-slip and wheel flange contact - wheels are worn seriously. In this study the curving noise was reviewed by using eigen-mode of wheel and waterfall plot which shows noise level in time-frequency domain. And also those were reviewed in viewpoint of stick-slip noise and wheel flange contact noise. Finally, the relationship between curving noise and wheel wear was studied.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.45-50
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• 2005

Stick type ignition coil(called a Cigar coil) is a kind of transformer for an automobile modulaized of distributer and electric cable. A material of cigar coil is PBT $GF30\%$ resin. This is an excellent engineering plastic with both mechanical and electrical properties. When we insert an HV terminal into the PBT $GF30\%$ resin jacket, it breaks the jacket, because the HV terminal is bigger than the jacket. It is a fatal on durability of a part. In this study, We used ANSYS FEM tool in order to stress analysis by contact. In order to automatically estimate possible maximum diameter of an HV terminal, we used an APDL. In the contact part, we considered the relation of the HV terminal's diameter with the amount of stress that occurred. This relation is able to be applied, in part, to the dimensions of the part design.

• 한국해양공학회지
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• 제31권4호
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• pp.281-287
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• 2017

In the case of fixed offshore wind turbines, scouring phenomena have been reported around sub-structures as a result of currents, which seriously damage the structural stability. A parametric study of the various sub-structures of a fixed offshore wind turbine was performed to investigate their effects on the scouring phenomena. For a suction bucket foundation and monopile, the effects of the stick-up heights and water depth were studied, respectively. The open source libraries, called OpenFOAM, were used to simulate a violent flow around a foundation. The numerical methods were selected based on a two-dimensional analysis of a suction bucket. Based on the results for various stick-up heights, a larger scouring region was observed with an increase in the stick-up height because of the down-wash flow around a foundation. Based on the results for various monopile water depths, the water depth had an insignificant effect on the scouring.

• 한국임상수의학회지
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• 제39권4호
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• pp.173-176
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• 2022

Intravenous catheterization is a common procedure in human and veterinary medicine. Occasionally, a catheter might break within the blood vessel, and the fragment may cause embolization, infections, or other severe complications, and therefore must be removed promptly. For a successful and low-risk removal, the fragment should be localized accurately; however, ultrasound may be challenging to perform on small dogs due to inadequate probes. We report the case of a 2-year-old, 2.6 kg, intact female toy poodle that presented to the veterinary medical center owing to a recent onion intake; the owner requested to induce emesis. A 24 gauge peripheral intravenous catheter was inserted into the cephalic vein prior to the emetic injection. When the clinician removed the catheter, a device breakage was observed. A tourniquet was applied immediately proximal to the elbow. Ultrasonography was performed with a high-frequency small-footprint linear array transducer, also called a hockey-stick probe, to localize the fragment. An additional ultrasound was performed before surgery to confirm the location of the catheter piece, which migrated 5 cm proximally. Afterward, a surgical intervention allowed us to retrieve the fragment. This report highlights the effectiveness of a hockey-stick probe to determine the location of a catheter fragment in small breed dogs.

• 복식
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• 제60권2호
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• pp.68-80
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• 2010

In order to get the information needed for the preservation and application of Korean traditional dyeing techniques to modern textiles products, the present study analyzed the color and color differences of dyed goods according to the contents of fabrics and the traditional techniques of dyeing the Buddhist priests' robes. A spectrophotometer was used to measure the differences in achromatic color according to dyeing techniques, dyestuff, kinds of dyed fabrics, and after-treatment methods. Through experiments based on the traditional dyeing techniques used by Korean Buddhist priests, a total of 144 pieces of dyed fabrics were made and all the colors of those 144 pieces were analyzed. Among three dyeing techniques tested; (1) dyeing with a dye-bath made of ink stick that was ground down with water, (2) dyeing with a dye-bath made by shaking a bag containing ink powder in water, and (3) dyeing with a dye-bath made by rubbing a boiled ink stick on a fabric, dyeing with a dye-bath made of ink stick that was ground down with water was shown to be the best technique in terms of coloring. For fabrics, ramie was the best of all three techniques in terms of making achromatic color. Starching and rubbing was the most effective after-treatment method used on both fabrics dyed with a grounded ink stick and on fabrics dyed by rubbing a boiled ink stick on them. As a whole, yangyeonmook, made from minerals' soot, is better than songyeonmook, which is made by burning old pine trees or yooyeonmook, which is made by burning oils from seeds. Therefore, yangyeonmook could help to preserve and utilize the traditional dyeing techniques of Korea in a practical way in modern life.

• 한국운동역학회지
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• 제31권3호
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• pp.155-161
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• 2021

Objective: There is a lack of studies using the 3D-2D image registration techniques on the mechanism of a shoulder injury for ice hockey players. This study aimed to analyze in vivo 3D glenohumeral joint arthrokinematics in collegiate ice hockey athletes and compare shoulder scaption with or without a hockey stick using the 3D-2D image registration technique. Method: We recruited 12 male elite ice hockey players (age, 19.88 ± 0.65 years). For arthrokinematic analysis of the common shoulder abduction movements of the injury pathogenesis of ice hockey players, participants abducted their dominant arm along the scapular plane and then grabbed a stick using the same motion under C-arm fluoroscopy with 16 frames per second. Computed tomography (CT) scans of the shoulder complex were obtained with a 0.6-mm slice pitch. Data from the humerus translation distances, scapula upward rotation, anterior-posterior tilt, internal to external rotation angles, and scapulohumeral rhythm (SHR) ratio on glenohumeral (GH) joint kinematics were outputted using a MATLAB customized code. Results: The humeral translation in the stick hand compared to the bare hand moved more anterior and more superior until the abduction angle reached 40°. When the GH joint in the stick hand was at the maximal abduction of the scapula, the scapula was externally rotated 2~5° relative to 0°. The SHR ratio relative to the abduction along the scapular plane at 40° indicated a statistically significant difference between the two groups (p < 0.05). Conclusion: With arm loading with the stick, the humeral and scapular kinematics showed a significant correlation in the initial section of the SHR. Although these correlations might be difficult in clinical settings, ice hockey athletes can lead to the movement difference of the scapulohumeral joints with inherent instability.

• 한국음향학회지
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• 제43권3호
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• pp.270-276
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• 2024

본 연구에서는 기계전자 제품에 사용되는 소재의 마찰실험을 통해 스틱슬립 특성을 분석하고 냉장고 내부에서 발생하는 이상소음을 저감하는 개선안을 제안하였다. 소재의 스틱슬립 현상을 분석하기 위해 마찰실험장치를 제작하고 마찰실험을 수행하였다. 또한 냉장고 내부에서 발생하는 이상소음의 현상과 위치를 분석하기 위해 내부부품의 진동과 소음 레벨을 측정하였다. 그리고 냉장고 현상분석 결과와 마찰실험 결과를 비교하여 냉장고 내부에서 발생하는 이상소음은 내부부품의 스틱슬립 현상에 의한 것임을 확인하였다. 마지막으로 이상소음을 저감하는 개선안을 제안하기 위해 다구찌 기법을 이용한 마찰실험을 수행하였다. 그리고 개선안을 냉장고에 적용하여 성능을 검증하였다.

• Fibers and Polymers
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• 제4권2호
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• pp.54-58
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• 2003

Previous research on healthcare workers’ protection has concentrated on liquid barrier protection by providing impermeable personal articles such as latex gloves. This property is of high importance but since most blood-borne pathogen transmissions in the healthcare industry are caused by needle-stick injuries, protection from sharp invasive instruments should also be of high concern. And since latex and alike provide no protection against needle-stick injuries, new protective systems need to be developed and evaluated. This part of the study provides a review regarding the current practice of protection and the serious problems that arise from needle-flick injuries. Additionally, the development of new protective system is described. In part II of the study, evaluation of the new system will be provided.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.690-693
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• 2006

As the silence of vehicle is more important, noise reduction of tire is more required. Noise of tire is divided into structure home noise and air borne noise. Tire tread has the property such as Hardness. Pattern Noise is caused by changing of tread hardness. This property has influence on the mechanisms which are Block Impact & Stick-slip sound. In the study, we found that the effect of Hardness is related to more Stick-Slip than Impact.

• 한국정밀공학회지
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• 제18권4호
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• pp.64-71
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• 2001

In general, precise linear actuators using piezoelectric element are driven by friction force. Exact understanding of friction plays an important role in analysis and control of a motor. In this research, we designed a precise linear actuator using piezoelectric elements and observed its dynamic characteristics. By varying phase angle difference and amplitudes of the sinusoidal waves that are driving inputs, we can know that it is possible to control moving direction and distance of the slider. As preload is increased, its moving distance is decreased. And also, we have modeled a precise linear actuator using stick slip friction models such as classical, Karnopp. and reset integrator. Finally, by comparing the results of simulation and experiment, it was verified that the model is well designed.