• 동의생리병리학회지
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• 제22권2호
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• pp.390-396
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• 2008

Osteoarthritis(OA) diseases are characterized by joint pain, tenderness, limitation of movement, crepitus, occasional effusion, and variable degrees of inflammation without systemic effects. We investigated the effects of Achyrantis radixs cream treatment and low intensity ultrasound in monosodium iodoacetate(MIA) induced experimental osteoarthritis rat. Sprague-Dawley 40 rats of 7-8 weeks, weight $250\;{\pm}\;50$ g were divided into four groups including the control group and ostoarthritis group(30 rats). Histopathological examination, Mankin's score, and immunohistochemical were performed. Histological findings in control group that are similar to those observed in human osteoarthritis, such as disorganization of chondrocytes, erosion and fibrillation of cartilage surface, and subchondral bone exposure. Safranin O-fast green staining revealed that marked diffuse reduction of proteoglycans and chondrocyte treated with MIA. The Mankin's score were closely correlated to the grade of histological findings. The level of Bax and caspase-3 expression decreased experimental groups. This study shows that a Acyranthes Radix cream treatment and low intensity ultrasound exerts a beneficial influence on the severity of chondral lesion in osteoarthritis rats. This treatments could related to a reduced level of chondrocyte apoptosis through anti-apoptotoc capacities of MIA-induced apoptotic protein overexpression.

• 한국정밀공학회지
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• 제25권7호
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• pp.116-123
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• 2008

In the fossil power plant, the reliability of the components which consist of the many welded parts depends on the quality of welding. The residual stress is occurred by the heat flux of high temperature during weld process. This decreases the mechanical properties as the strength of fatigue and fracture or causes the stress corrosion cracking and fatigue fracture. Especially, the accidents due to the residual stress occurred at the weld parts of high-temperature and high-pressure pipes and steam headers. Also, the residual stress of the welded part in the recently constructed power plants has been brought into relief as the cause of various accidents. The aim of this study is the measurement of the residual stress using the x-ray diffraction method. The merits of this are more accurate and applicable than other methods. The materials used for the study is P92 steel for the use of high temperature pipe on super critical condition. The variables of tests are the post-weld heat treatment, the surface roughness and the depth from the original surface. The test results were analyzed by the distributed characteristics of the full width at half maximum intensity (FWHM) in x-ray diffraction intensity curve and by the relation of hardness with FWHM.

• Advances in materials Research
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• 제6권3호
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• pp.233-243
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• 2017

This paper describes an investigation on the effect of using three different filler metals on fatigue behavior of mechanical structures welded. The welding is carried out on the steel A510AP used for the manufacture of gas cisterns and pipes. The welding process used is manual welding with coated electrodes and automatic arc welding. Compact tension CT50 specimen has been used. The three zones of welded joint; filler metal FM, heat affected zone HAZ and base metal BM have been investigated. The results show that the crack growth rate CGR is decreasing respectively in BM, FM and HAZ; however, this variation decreases when stress intensity factor SIF increases. For low values of SIF, the CGR is inferior in the over-matched filler metal of which the value of mismatch M is near unity, but for high values of M the CGR is superior, and the effect of the over-matching on CGR becomes negative. No deviation of the crack growth path has been noticed.

• 전기학회논문지
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• 제62권7호
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• pp.1009-1013
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• 2013

In this study, we developed a fiber-optic goniometer for the continuous measurement of knee joint angle which provides important medical information on Alzheimer's disease. The fiber-optic goniometer is composed of a light-emitting diode (LED), a plastic optical fiber (POF), and a voltage output photodiode (PD). As a sensing part of the fiber-optic goniometer, a unclad fiber with regular intervals of 1 mm was fabricated to improve efficiency of bending loss according to the angle variation of knee joint. The emitting light with a center wavelength of 470 nm from a LED is guided by a POF to the PD, the transmitted light is then attenuated by the bending loss inside the bent POF. The intensity variation of the light transmitted from the POF gives rise to a change in output voltage in the fiber-optic goniometer. Therefore, we measured the real-time output voltage of the proposed fiber-optic goniometer using the unclad fiber according to the knee joint angle. Through the repeated experiments, the fiber-optic goniometer shows that it has a reversibility and a wide measurable angle range.

• The Journal of Korean Physical Therapy
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• 제20권2호
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• pp.11-17
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• 2008

Purpose: This study examined the application of electric stimulation to the auricle acupoint (frequency 2 Hz, stimulation level: noxious) with 30 elderly people over 65 years that received treatment in a rural hospital to determine the influence of pain, gait and balance in the aged with knee joint disease. Methods: The subjects were divided into three groups; the degenerative joint diseases (DJD) group (1 male, 9 females), the total knee replacement (TKR) group (1 male, 9 females) and the control group (1 male, 9 females). Auricualr electrical stimulation (AES) was applied with low frequency, high intensity transcutaneous electrical nerve stimulation for 10 seconds per each point. Results: 1. For the change of pain according to AES, there was interaction in the resting period (p<0.001) and gait (p<0.001) and pain of the DJD group and TKR group was decreased. 2. The range of motion (ROM) of the knee joint showed a significant difference in interaction for each group of elderly people (p<0.001) and the ROM for the DJD group and TKR group of elderly people was increased. 3. In the analysis of gait speed changes, there was a significant difference in interaction for each group of elderly people (p<0.001) and for gait speed in the DJD group and TKR group of elderly people. 4. It was found in the change of static balance that there was a significant difference in interaction for each group of elderly people (p<0.01) and balance capacity in the DJD group and TKR group of elderly people was increased. Conclusion: The aged with knee joint disease have pain, and a decreased function of gait and balance. AES was an excellent treatment for control of pain, and an excellent treatment to enhanced joint functions. AES was useful for improving gait and balance due to decreased pain.

• 한국전문물리치료학회지
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• 제26권3호
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• pp.11-22
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• 2019

Background: Sling exercises are frequently used for the rehabilitation process of patients with shoulder joint injuries, but research on the significant frequency intensity and appropriate treatment duration for sling exercises with local vibration stimulation is lacking. Objects: The aim of this study was to investigate the effects of sling exercise with vibration on shoulder range of motion (ROM), muscle strength, pain, and dysfunction in patients with a medical diagnosis of shoulder joint injury. Methods: Twenty-two patients were randomly assigned to the experiment and control groups. Six sling exercises with and without 50 Hz vibrations were applied in the experiment and control groups, respectively. Each exercise consisted of 3 sets of 5 repetitions performed for 6 weeks. The assessment tools used included shoulder joint range of motion, muscle strength, pain level, and shoulder pain and disability index for functional disability. We conducted re-evaluations before and 3 and 6 weeks after intervention. The changes in the measurement variables were analyzed and compared between the two groups. Results: The ROM of the external rotation of the shoulder joint had a significant interaction between the group and the measurement point (F=3.652, p<.05). In both groups, we found a significant increase in external rotation angle between the measurement points (p<.05). The flexor strength of the shoulder joint significant interaction between the group and the measurement point (F=4.247, p<.05). Both the experiment (p<.01) and control groups (p<.05) showed a significant increase in shoulder flexor strength at the measurement points. After 6 weeks of the interventions, both the groups showed significantly improved VAS (p<.01), SPADI (p<.01), and orthopedic tests (p<.01). However, there was no significant difference between the group and the measurement point in terms of the clinical outcomes observed. Conclusion: The sling exercise with local vibration of 50 Hz affected the external rotation of the shoulder range of motion and improved shoulder flexor strength in the patients with shoulder injuries. Therefore, we propose the use of the sling exercise intervention with vibration in the exercise rehabilitation of patients with shoulder joint injuries.

• 한국조경학회지
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• 제36권4호
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• pp.111-119
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• 2008

합리식은 배수시설을 설계하기 위한 기본방정식으로 이용되고 있으며, 유출계수, 강우강도와 유역면적의 함수이다. 본 연구에서는 조경공간의 배수시설설계에 이용되는 합리식의 유출계수를 블록포장지역을 대상으로 지역적 강우분포를 고려하여 산정하였다. 합리식의 유출계수는 강우강도와 유출량의 비로 나타낼 수 있다. 강우강도는 재현기간과 강우지속기간의 함수로, 강우의 특성상 지역에 따라 변한다. 따라서 합리식의 유출계수는 동일한 재현기간과 강우지속기간일지라도 지역에 따라 강우강도가 변하므로 지역에 따라 변한다. 또한, 강우강도와 유출량의 비는 강우량에 대한 손실량에 따라 결정되므로, 손실량을 산정하기 위하여 본 연구에서는 Horton의 침투법칙 중 종기침투능을 이용하였다. 블록포장지역의 침투는 줄눈을 통하여 발생하며, 줄눈은 시간이 지남에 따라 황사, 오염물질, 꽃가루 등에 의하여 공극이 메워지고, 답압 등에 의하여 다져질 것이므로, 침투능은 감소할 것이다. 시공연한이 다른 6개 지역의 블록포장지역을 대상으로 Horton의 종기침투능을 산정하여 시간이 지남에 따라 침투능이 감소하는 것을 확인하였고, 지역별 재현기간 10년에 대한 강우지속기간 10, 20 및 30분에 해당하는 강우강도를 선정하여, 합리식의 유출계수를 산정하였다. 본 연구의 결과로, 산정 된 블록포장지 역의 유출계수 범위는 재현기간 10년, 강우지속기간 10분의 경우 지역에 따라 $0.94{\sim}0.84$의 범위를 가진다.

• 한국융합학회논문지
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• 제12권11호
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• pp.359-369
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• 2021

본 연구는 국민건강영양조사 제 8기 원시 자료를 활용하여 65세 이상 2,701명의 정상 노인과 만성질환 노인의 활동 제한에 영향을 주는 요인을 파악하기 위해서 복합표본 로지스틱 회귀분석을 실시하였다. 만성질환 노인이 정상 노인보다 활동 제한을 느낀다고 조사되었다. 뇌졸중, 고혈압 환자의 활동 제한 요인으로는 주관적 건강 상태, 경제 수준, 스트레스 인지 정도, 중강도의 일과 여가이다. 심장질환 환자의 활동 제한 요인으로는 주관적 건강 상태, 경제 수준이었으며, 관절질환 환자의 활동 제한의 요인으로는 주관적 건강 상태, 고강도의 일과 여가이다. 폐 질환 환자의 활동 제한요인으로는 교육 수준, 고강도의 일과 여가이며, 내분비계 환자의 활동 제한의 요인으로는 주관적 건강 상태, 스트레스 인지 정도, 고강도의 일과 여가이며, 암 환자의 활동 제한의 요인으로는 주관적 건강 상태, 스트레스 인지 정도, 중강도의 일과 고강도의 여가이다. 만성질환 노인의 지속적인 활동 참여를 위한 재활프로그램과 정책적 지원이 필요하다.

• Structural Engineering and Mechanics
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• 제63권6호
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• pp.809-824
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• 2017

The accurate evaluation of wind characteristics and wind-induced structural responses during a typhoon is of significant importance for bridge design and safety assessment. This paper presents an expectation maximization (EM) algorithm-based angular-linear approach for probabilistic modeling of field-measured wind characteristics. The proposed method has been applied to model the wind speed and direction data during typhoons recorded by the structural health monitoring (SHM) system instrumented on the arch Jiubao Bridge located in Hangzhou, China. In the summer of 2015, three typhoons, i.e., Typhoon Chan-hom, Typhoon Soudelor and Typhoon Goni, made landfall in the east of China and then struck the Jiubao Bridge. By analyzing the wind monitoring data such as the wind speed and direction measured by three anemometers during typhoons, the wind characteristics during typhoons are derived, including the average wind speed and direction, turbulence intensity, gust factor, turbulence integral scale, and power spectral density (PSD). An EM algorithm-based angular-linear modeling approach is proposed for modeling the joint distribution of the wind speed and direction. For the marginal distribution of the wind speed, the finite mixture of two-parameter Weibull distribution is employed, and the finite mixture of von Mises distribution is used to represent the wind direction. The parameters of each distribution model are estimated by use of the EM algorithm, and the optimal model is determined by the values of $R^2$ statistic and the Akaike's information criterion (AIC). The results indicate that the stochastic properties of the wind field around the bridge site during typhoons are effectively characterized by the proposed EM algorithm-based angular-linear modeling approach. The formulated joint distribution of the wind speed and direction can serve as a solid foundation for the purpose of accurately evaluating the typhoon-induced fatigue damage of long-span bridges.

• 한국전산구조공학회논문집
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• 제17권1호
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• pp.83-91
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• 2004

랜덤동요된 조화가진력을 받는 임팩트시스템의 비선형거동을 개발된 반해석적절차에 의해 확률영역에서 분석하였다. 반해석적절차는 path-integral solution을 이용하여 임팩트시스템의 추계론적 미분방정식으로부터 구함으로 얻어진다. 결합확률밀도함수의 전개를 구하고 시스템의 비선형거동 특성인 혼돈거동에 대하여 분석하고 노이즈의 영향을 시간영역과 확률영역에서 알아보았다. 결과로부터 반해석적절차는 결합확률밀도함수를 통하여 임팩트시스템의 거동에 대한 정보를 제공하는 것을 알 수 있었다. 노이즈의 영향은 혼돈거동의 특성을 약화시키며 궁극적으로 사라지게 함을 알 수 있었으며 또한 혼돈거동의 특성이 상대적으로 높은 노이즈아래에서도 남아있는 것을 밝혔다. 결합확률밀도함수는 응답앙상블이 약정상과정임을 확인시켜 주었다.