• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.93-96
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• 2003

Laser beam welding process is a relatively new process in comparison with arc welding process, but it is expected to apply widely because of the many advantages, and research and development of that process is being progressed actively for the practical use. the application of this welding process has been restricted due to the high initial investment and the need of precise processing against the material, but cost reduction and thick plate welding in high speed have become practial by recent technological development, and this welding process to not only small parts in automobile, machinery and physicochemical field, but also a large structure and pipe line are being applied. In order to utilize this welding process appropriately to a steel structure, the properties of welding residual stresses and fracture toughness in welded joints are to be investigated for relibilty. On this study, after performing the finite element analysis, thermal and residual stress properties have been examined to the general structural steel (HT50) by laser beam welding. Besides, the property of fracture toughness has been investigated by the Charpy impact test and 3-points bending CTOD test carried out in the range of temperature between $-60^{\circ}C$ and $20^{\circ}C$. From the research results it is revealed that the maximum residual stress appears in the center of plate thickness and the fracture toughness is influenced by strength mis-match.

• Journal of Sport and Applied Science
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• 제7권3호
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• pp.19-26
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• 2023

Purpose: This study attempted to investigate the effect of functional rehabilitation exercise for posture correction on physical strength factors and physical balance. Research design, data, and methodology: It consisted of 40 experimental groups that applied functional rehabilitation exercises to 80 people with posture imbalance and 40 comparative groups that performed general exercises, and was conducted four times a week, once for 40 minutes, and for 12 weeks. Results: D.S. (p<.o1) among F.M.S., a moving assessment. It increased significantly from the dictionary, and H.S. (p<.o5). I.L(p<.o5). S.M(p<.o5). A.S.L.R(p<.o5). T.S.P(p<.o01). It was confirmed that R.S. (p<.o5) decreased more after than before. In other words, Functional rehabilitation exercise was effective in improving physical balance. PAPS flexibility (bending forward) (p<.o1). Muscle strength (grip strength test) (p<.o1). Quickness (long jump) (p<.o1). Functional rehabilitation exercise was found to be effective in muscle strength, agility, and flexibility, but not in cardiopulmonary endurance. Pain: Based on the NRS scale (1-10 points). The experimental that there was a significant interaction between the groups.(F=38.583, P=.000). In the comparative group, there was no significant difference in the pre-post, and it was found that the pain level in the experimental group decreased after the pre-post (p<.001). Conclusion: As a result of the above study, it was confirmed that functional rehabilitation exercise improves physical strength factors and physical balance ability, and also affects physical pain reduction due to physical imbalance.

• 한국전문물리치료학회지
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• 제24권2호
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• pp.37-47
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• 2017

Background: Active trigger points (TrPs) of the suboccipital muscles greatly contribute to the occurrence of chronic tension-type headache, with increased sensitivity of TrPs and facilitated referred pain. Objects: This study aimed to investigate whether the integration of high-frequency diathermy into suboccipital release is more beneficial than the use of suboccipital release alone. Methods: Thirty subjects were assigned to either experimental group-1 (EG-1) to undergo suboccipital release combined with high-frequency diathermy (frequency: 0.3 MHz, and electrode type: resistive electronic transfer), or EG-2 to undergo suboccipital release alone, or the control group (CG) with no intervention, with 10 subjects in each group. The assessment tools included the headache impact test 6 (HIT-6), perceived level of tenderness, neck disability index, and neck mobility. Intervention was performed for 10 minutes, twice per week, for 4 weeks, and measurements were performed before and after the interventions. Results: The between-group comparison of the post-test values and changes between pretest and post-test showed significant differences for all parameters at p<.05, except for the left-to-right lateral bending range. In the post hoc test, EG-1 showed significant differences for the parameters in comparison with the CG, while no significant differences in the perceived tenderness level, on both temporal regions, were found between EG-2 and CG. Furthermore, the HIT-6 score and perceived tenderness level, in the right temporal region, showed significant differences between EG-1 and EG-2. In the within-group comparison, EG-1 and EG-2 appeared to be significantly different between pretest and post-test (p<.05), except for the perceived tenderness level in the right temporal region, with significance for the EG-1 group only (p<.05). Conclusion: These findings suggest that the suboccipital release technique may be advantageous to improve headache, tenderness, and neck function and mobility, with more favorable effects with the incorporation of high-frequency diathermy.

• 한국건설순환자원학회논문집
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• 제11권4호
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• pp.484-492
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• 2023

본 연구에서는 전기화학적 염화물 추출(ECE) 완료된 RC 보의 구조적 거동을 기존에 주로 사용되었던 부착 강도 측정이 아닌 3점 재하 시험을 통해 분석했다. 그 결과, ECE 처리에 의해 콘크리트 보의 휨 강성은 저하되었으나, 최대하중 측면에서 강도는 향상되는 것으로 나타났다. 또한, ECE에 의해 인장 변형률이 증가하여 인장 균열에 대한 저항성은 향상되었으며, 관성 모멘트 감소율은 감소하였다. 이러한 구조적 거동 측면의 이점에도 불구하고 연성 및 휨 강성은 저하되었다. 콘크리트보의 휨 강성은 선형 탄성 범위에서 유효 단면적의 손실로 인해 감소됐고, 실제로 인장변형에 의해 파손된 상태에서 단면 2차 모멘트는 약 70 %의 손실되었다. 그러나 이러한 단면 손실에 의한 관성 모멘트 감소율은 ECE에 의해 더 낮아졌는데, 이는 균열에 대한 저항성이 증가되는 반면, 변형량이 증가되어 사용성 측면에서의 위험성은 더 증가됨을 의미한다.

• 전산구조공학
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• 제8권4호
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• pp.87-97
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• 1995

2차원 유한요소 모델의 동일한 형상과 하중 조건에 있어서 6절점 요소의 굽힘 강성은 8절점 요소의 굽힘 강성보다 더 크게 나타난다. 이와 같은 현상은 3차원 16절점 요소와 20절점 요소에서도 나타나며, 완전 요소의 중간 절점들을 제거하므로 인하여 나타난다. 따라서 이 현상을 상대적 강성강화 현상이라 할 수 있다. 강성강화 현상을 보정하기 위한 매우 효과적인 방법으로 가우스 적분점 수정법을 도출하였으며, 이 방법은 확장적인 강성과 같이 다른 종류의 강성을 변화시키지 않으며, 또한 패취시험을 통과하였다. 적분점 수정량은 재료의 포아송비의 함수로 나타나며, 2차원 평면응력 상태와 평면변형율 상태에 대한 두개의 수정식을 구하였고, 또한 3차원 고체요소에 대하여 확장하였다. 가우스 적분점 수정법의 효과를 검증하기 위하여 보와 판의 자유 및 강제운동 문제를 해석하였으며, 등방성 적층 보와 판에 대해서도 단층보와 단층판과 같은 방법으로 적용하여 그 효율성을 입증하였다.

• 대한치과교정학회지
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• 제36권2호
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• pp.145-152
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• 2006

본 연구는 교정용 선재의 직경을 증가시키기 위한 방법으로 무전해도금법의 이용 가능성 여부를 전기도금법과의 비교를 통해 알아보고자 시행되었다. 0.016 인치 스테인레스 스틸 교정용 선재에 도금을 위한 전처리를 시행한 후, 시중에 판매되는 무전해니켈도금액($Hessonic-Gr^{(R)}$, 신풍금속, 한국)을 사용하여 $90^{\circ}C$ 온도에서 0.018 인치 직경이 될 때까지 도금을 시행하였다. 무전해도금 과정 중 시간에 따른 직경증가율을 구하는 한편, 도금 후 세 지점의 직경을 계측하여 균일성을 평가하였다. 도금 금속의 정성분석을 위하여 X-선 회절분석을 시행하는 한편, 물성검사를 시행한 후 전기도금한 경우와 각각 비교 분석하였다. 연구결과 무전해도금한 군이 전기도금을 시행한 군보다 강성, 항복강도, 극한강도 모두 높은 경향을 보였으며 강성과 극한강도에서 통계적으로 유의한 차이를 나타내었다 (p<0.05). 또한 무전해도금한 군의 직경증가율은 $0.00461{\pm}0.00003mm/5min$ (0.00092 mm/min)로, 전기도금한 군의 직경증가율 $0.00821{\pm}0.00015mm/min$와 차이를 보였다. 도금 후 세 지점의 직경을 계측하여 균으성을 평가한 결과, 두 가지 도금법 모두에서 균일한 양상을 보였다. 이상의 결과로 무전해도금법을 통해 직경이 증가된 선재가 전기도금 법에 의해 직경이 증가된 선재보다 기존의 선재와 가까운 물성을 보임을 알 수 있었으며, 이의 임상적 적응을 위해서는 도금시간의 감소가 필요함을 알 수 있었다.

• Journal of Acupuncture Research
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• 제19권3호
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• pp.107-114
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• 2002

Objective : This study was designed to find the most effective and safest way to overcome Lumbago due to blood stasis and sprain involved in a few Meridian Tendino-musculatures by evaluating the effect of two kinds of Dong-gi(Dong-qi) Acupuncture(DGA) and by reporting their side effects. Material : 97 patients of out and admission patients were selected, who were diagnosed with lumbar sprain caused by repetitive bending, heavy weight lifting, unsuitable posture, concussion and falling down and whose Lumbago due to blood stasis and sprain in the concept of oriental medicine. Methods : 97 patients were divided into three groups. One is exclusive DGA group to which DGA and the method retaining needles on the acupoints for about 20 minutes were applied, the other is DGA combined active exercise group in which patients stretched their Meridian Tendino-muscuIatures with their hips moving up and downward repeatedly during DGA, the third is DGA combined passive exercise group in which patients were made to flex or extend their bodies on the auto flexion-distraction table in a prone position, from 10 to 20 degree, during DGA. In each group, bed rest, physical therapy and herbal medicine were used according to symptoms, in addition to DGA. In DGA method, "Su(Shu)" points of the meridian related to the involved Meridian Tendino-musculature were mainly chosen, that is, Sokkol(Shugu, B65), Hugye(Houxi, SI3), ChungJo(Zhongzhu, TE3) were used, for most LBP belonged to Bladder and Gallbladder Meridian Tendino-musculature disorders. Pyong-Bo-Pyong-Sa(Ping-Bu-Ping-Xie) such as Dong-Gi and Yeom-Jeon(Nian-Zhuan) was applied as Bo-Sa method. For evaluation of effectiveness, new score system was devised by severity of pain and range of movement. the score was given twice at patients' first and last visit and the difference between first and last score was regarded as a evaluation scale, the effectiveness was classified into four grade by evaluation scale.(scale : 12-15; excellent, 8-11; good, 4-7; fair, 0-3; bad) Results : 1. Exclusive DGA, DGA combined active exercise and DGA combined passive exercise group showed 97, 87 and 89% in effectiveness. 2. Exclusive DGA, DGA combined active exercise and DGA combined passive exercise group showed no aggravation of pain, range of movement. 3. In blood test of 34 patients, only one patient showed abnormal rise of sGOT, sGPT and $\gamma$-GTP at his first visit and the others didn't show any detrimental change. DGA had no bad influence upon BUN and creatinine of patients. Conclusion : For complex theraphy combining DGA, exercise, physical therapy and Herbal medicine proved to be highly effective on treating lumbago due to blood stasis and sprain, this is expected to be available for clinical use.