• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.700-705
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• 2005

This study presents a fatigue line with a plastic rotational angle to a great extent of plastic strain of Low-Cycle-fatigue period, such as earthquake, etc. This fatigue line with a plastic rotational angle is measured and analysed more simply in practice rather than Woehler's fatigue line which is developed in stress variation of the structure. It shows that the slope of fatigue line with a plastic rotational angle is equal to that with plastic strain through the experiments by proving the correlation that the plastic strain ratio is directly proportional to the plastic rotational angle in plastic hinge.

• Journal of Oral Medicine and Pain
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• 제24권4호
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• pp.455-466
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• 1999

The purpose of this study was to investigate the magnitude of mandibular rotational torque movements in subjects with TMJ sounds, and to analyse correlation between quantitative characteristics of TMJ sounds and mandibular rotational torque movement. Twenty dental college students with TMJ clicking and twenty students without any TMD signs and symptoms were examined by mean of SonoPak and Rotate program of BioPAK system(Bioresearch Inc. MilWaukee, wisconsin, USA) in this study. Mandibular rotational torque movements were recorded and analysed during maximum mouth opening, protrusion, and lateral excursion in frontal and horizontal planes. The obtained results were as follows: 1. On maximum mouth opening, mandibular rotational angle and distance of clicking group were significantly greater than those of control group in frontal plane. (P<0.05). 2. During maximum mouth opening closing, maximum mandibular rotational angle and distance of clicking group were significantly greater than those of control group in frontal plane. (P<0.01). 3. On protrusion, mandibular rotational angle and distance of clickin group were significantly greater than those of control group in horizontal plane. (P<0.05). 4. On lateral excursion, there was no significant difference in mandibular rotational angle and distance between clicking group and control group in frontal and horizontal planes. 5. There were significant correlations between peak amplitude of TMJ sounds and maximum mandibular rotational distance during maximum mouth opening (r=-.481) and mandibular rotational distance on maximum mouth opening (r=-.455) in horizontal plane. 6. There were significant correlations between Above 300/(0-300)Hz ratio of TMJ sounds and mandibular rotational angle (r=-.499) and distance (r=-.457) on maximum mouth opening in frontal plane.

• Journal of Oral Medicine and Pain
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• 제25권2호
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• pp.173-189
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• 2000

The purpose of this study was to evaluate the effect of specific head positions on the mandibular rotational torque movements in maximum mouth opening, protrusion and lateral excursion. Thirty dental students without any sign or symptom of temporomandibular disorders(TMDs) were included as a control group and 90 patients with TMDs were selected and examined by routine diagnostic procedure for TMDs including radiographs and were classified into 3 subgroups : disc displacement with reduction, disc displacement without reduction, and degenerative joint disease. Mandibular rotational torque movements were observed in four head postures: upright head posture(NHP), upward head posture(UHP), downward head posture(DHP), and forward head posture(FHP). For UHP, the head was inclined 30 degrees upward: for DHP, the head was inclined 30 degrees downward: for FHP, the head was positioned 4cm forward. These positions were adjusted with the use of cervical range-of-motion instrumentation(CROM, Performance Attainment Inc., St. Paul, U.S.A.). Mandibular rotational torque movements were monitored with the Rotate program of BioPAK system (Bioresearch Inc., WI, U.S.A.). The rotational torque movements in frontal and horizontal plane during mandibular border movement were recorded with two parameters: frontal rotational torque angle and horizontal rotational torque angle. The data obtained was analyzed by the SAS/Stat program. The obtained results were as follows : 1. The control group showed significantly larger mandibular rotational angles in UHP than those in DHP and FHP during maximum mouth opening in both frontal and horizontal planes. Disc displacement with reduction group showed significantly larger mandibular rotational angles in DHP and FHP than those in NHP during lateral excursion to the affected and non-affected sides in both frontal and horizontal planes(p<0.05). 2. Disc displacement without reduction group showed significantly larger mandibular rotational angles in FHP than those in any other head postures during maximum mouth opening as well as lateral excursion to the affected and non-affected sides in both frontal and horizontal planes. Degenerative joint disease group showed significantly larger mandibular rotational angles in FHP than those in any other head postures during maximum mouth opening, protrusion and lateral excursion in both frontal and horizontal planes(p<0.05). 3. In NHP, mandibular rotational angle of the control group was significantly larger than that of any other patient subgroups. Mandibular rotational angle of disc displacement with reduction group was significantly larger than that of disc displacement without reduction group during maximum mouth opening in the frontal plane. Mandibular rotational angle of disc displacement without reduction group was significantly larger than that of disc displacement with reduction group or degenerative joint disease group during maximum mouth opening in the horizontal plane(p<0.05). 4. In NHP, mandibular rotational angles of disc displacement without reduction group were significantly larger than those of the control group or disc displacement with reduction group during lateral excursion to the affected side in both frontal and horizontal planes. Mandibular rotational angle of disc displacement without reduction group was significantly smaller than that of the control group during lateral excursion to the non-affected side in frontal plane. Mandibular rotational angle of disc displacement without reduction group was significantly larger than that of disc displacement with reduction group during lateral excursion to the non-affected side in the horizontal plane(p<0.05). 5. In NHP, mandibular rotational angle of the control group was significantly smaller than that of disc displacement with reduction group or disc displacement without reduction group during protrusion in the frontal plane. Mandibular rotational angle of disc displacement without reduction group was significantly larger than that of the disc displacement with reduction group or degenerative joint disease group during protrusion in the horizontal plane. Mandibular rotational angle of the control group was significantly smaller than that of disc displacement without reduction group or degenerative joint disease group during protrusion in the horizontal plane(p<0.05). 6. In NHP, disc displacement without reduction group and degenerative joint disease group showed significantly larger mandibular rotational angles during lateral excursion to the affected side than during lateral excursion to the non-affected side in both frontal and horizontal planes(p<0.05). The findings indicate that changes in head posture can influence mandibular rotational torque movements. The more advanced state is a progressive stage of TMDs, the more influenced by FHP are mandibular rotational torque movements of the patients with TMDs.

• 척추신경추나의학회지
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• 제7권1호
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• pp.27-34
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• 2012

Objectives : The purpose of this study is to find out the relation between 4th lumbar rotational malposition and scoliosis. Methods : We investigated 22 cases of patients who were diagnosed as scoliosis. We used AP & Lateral view X-ray for patients. And we analysed the relation between 4th lumbar rotational malposition and scoliosis. Results : P-value was 0.436 between 4th lumbar rotational amount and lordotic angle, and was 0.758 between 4th lumbar rotational amount and wedge angle(p>0.05). And p-value was 0.022 between 4th lumbar rotational amount and scoliotic apex rotational amount(p<0.05), but was 0.286 between 4th lumbar rotational amount and Cobb's angle(p>0.05). Conclusions : The results suggest that 4th lumbar rotational malposition was statistically correlation with scoliotic apex rotational malposition, was not Cobb's angle, 4th lumbar lordotic & wedge angle.

• Journal of Oral Medicine and Pain
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• 제22권2호
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• pp.207-217
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• 1997

This study was performed for Investigation of the magnitude of mandibular positional change in maximum mouth opening. protrusion, lateral excursion, gum and peanut chewing with BioPAK system(Bioresearch Inc. USA) which can analyze mandibular rotational torque movements. For this study 17 female patients with Temporomandibular joint(TMJ) closed lock and 18 female control without any Temporomandibular disorders(TMDs) signs and premature occlusal contact were included. The obtained results were as follows : 1. In maximum mouth opening, the mandibular rotational angle and distance of patients were significantly greater than those of control group in horizontal plane(P<0.05). 2. In protrusion, the mandibular rotational angle and distance of patients were significantly greater than those of control group in frontal and horizontal plane(P<0.01, P<0.05). 3. The mandibular rotational angle and 야stance in lateral excursion to affected side of patients were significantly greater than those in lateral excursion to non-affected side in frontal plane(P<0.05). 4. The mandibular rotational angle in gum chewing to affected side of patients was significantly greater than that in gum chewing to non-affected side in frontal plane. 5. The mandibular rotational angle and distance in peanut chewing to affected side of patients were significantly greater than those in peanut chewing to non-affected side in frontal and horizontal plane. 6. The mandibular rotational angle and distance in peanut chewing to affected side of patients were greater than those in gum chewing, and was the same result in control group in frontal and horizontal plane.

• Journal of Mechanical Science and Technology
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• 제15권6호
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• pp.813-820
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• 2001

Solutions of inviscid rotational flows near the corners of an arbitrary angle and within a triangle of arbitrary shapes are presented. The corner-flow solutions has a rotational component as a particular solution. The addition of irrotatoinal components yields a general solution, which is indeterminate unless the far-field condition is imposed. When the corner angle is less than 90$^{\circ}$the flow asymptotically becomes rotational. For the corner angle larger than 90$^{\circ}$it tends to become irrotational. The general solution for the corner flow is then applied to rotational flows within a triangle (Method I). The error level depends on the geometry, and a parameter space is presented by which we can estimate the error level of solutions. On the other hand, Method II employing three separate coordinate systems is developed. The error level given by Method II is moderate but less dependent on the geometry.

• 구강회복응용과학지
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• 제24권1호
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• pp.57-65
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• 2008

연구목적 : 본 연구에서는 rotational freedom을 측정할 수 있는 기구를 개발하여 시중에서 유통되고 있는 국산 임플란트 및 다양한 국적의 임플란트들의 기계적인 가공오차들을 측정하여 다양한 임플란트 시스템의 component간의 기계적인 안정성을 평가하고자 한다. 또한 본 연구에서는 더 나아가 최근에 임플란트 abutment로 각광을 받고 있는 각종 ceramic abutment의 절삭 가공오차에 관한 항목을 측정하여 임플란트 제조사 및 임상의들에게 올바른 정보를 제공하고자 한다. 연구재료 및 방법 : 국내에서 유통되는 외부연결구조의 외국산 임플란트 시스템(Nobel Biocare, Anthorgyr)과 국산 시스템(Neobiotec)과 내부연결구조의 임플란트 시스템(외국산:Nobel Biocare, Anthorgyr, Straumann, Frident Dentsply, 국산:Dentium) 별로 임플란트 fixture, abutment, analog를 서로 교차 연결하여 회전각도측정기(rotational angle measuring device)로 freedom of rotational angle을 측정하였다. 국산 외부연결구조의 지르코니아 abutment(ZirAce)를 외부연결구조의 임플란트 시스템(Neobiotec, Nobel Biocare, Anthorgyr)의 fixture와 analog와 교차연결하여 freedom of rotational angle을 측정하였다. 연구결과 : 국산 외부연결구조의 임플란트 시스템은 약 2.67도(fixture와 abutment 연결시), 내부연결구조의 임플란트는 약 4.3도(fixture와 abutment 연결시)의 rotational freedom을 보였다. 국산 지르코니아 abutment는 외국산 및 국산 외부연결구조 임플란트 시스템과 상관없이 3도 이하(fixture와 연결시)의 결과를 보였다. 결 론 : 시제품으로 제작된 디지털 회전각도측정기는 높은 분해능을 갖고 있었으며, 국산 임플란트의 기계적 가공오차는 외국산 임플란트와 거의 유사했다. 국산 세라믹 abutment의 기계적 가공오차는 fixture 제조회사별로 다르게 나타났지만 같은 회사의 절삭가공된 금속 abutment와 비교시 가공오차가 더 적었다.

• Journal of Oral Medicine and Pain
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• 제23권2호
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• pp.143-155
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• 1998

This study was performed to investigate the factor that might affect mandibualr body rotation. For the study, 115 patients with temporomandibular disorders and 35 dental students without angy signs and symptoms of temporomandibular disorders were randomly selected as the patient group and the contreol group, respectively. Preferred chewing side, Angle' classification, lateral guidance pattern, and affected side were clinically recorded, and the amount of Mandibular body rotational torque movement was measured in wide opening and closure, in right and left excursion with vertical and lateral distance in frontal plane, right and left rotational angel in horizontal and in frontal plane. Masticatory muscle activity of anteriorocclusal contact pattern on maximal hard biting were also observed synchronously with BioEMG and T-Scan , respectively. The observed items were muscle activity of anterior temporalis and superficial masseter, and tooth contact status related to contact number, force, duration, and occlusal unbalance between right and left arch. The data collected were analyzed by SAS statistical program. The results of this study were as follows : 1. Mean value of vertical distance in frontal plane in wide opening and closure was more in control subjects than in patients, but there was no difference for rotational angle. In right excursion, rotational angles were greater in patient group than in control group. 2. Comparison among the subjects by preferred chewing side did not reveal any significant difference, but comparison among patients by affected side showed more rotational amount in bilaterally affected patients than in unilaterally affected patients. 3. Comparison among the subjects by Angle's classification or lateral guidance pattern revealed no difference. There was also no difference between preferred chewing side and contralateral side, and between affected side and contralateral side. 4. Positive correlation in madibular rotational torque movements were observed among vertical distance, total horizontal rotation angle, electromyographic activity of anterior temporalis, tooth contact number, and tooth contact force but total frontal rotation angle almost did not show any correlation with other variables except vertical distance.

• 한국공간구조학회논문집
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• 제4권1호
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• pp.69-75
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• 2004

저층 철골조의 시공에 있어서 더블앵글 접합부는 매우 효과적인 접합부의 한 형태로 취급된다. 더블앵글 접합부의 접합부 강성은 앵글의 두께, 볼트 게이지 거리, 볼트의 개수 등과 같은 여러 변수에 따라서 변화한다. 본 연구에서는 볼트수의 변화가 더블앵글 접합부의 모멘트-회전각 관계에 미치는 영향을 파악하기 위하여 세 개의 더블앵글 접합부 실험이 수행되었다. 각각의 실험결과에 근거하여 각 실험에 사용된 더블앵글의 회전강성은 회귀분석을 통하여 산정되었다. 회귀분석결과 더블앵글 접합부의 접합부 강성은 볼트의 개수가 증가함에 따라서 함께 증가한다는 결론을 얻었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.458-461
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• 1995

A new type of rotational motor which is developed has a resolution smaller than 10 $^{-4}$ radian and can be accessed for full rotational angles. The operation principle of the motor is based on inchworm motion of two belt driving mechanism. Flexure hinge mechanism, which is pertinent to symmetry construction of the motor, is designed to minimze the effort to frame and is analyzed by using finite element method. Depending on input signal amplitude, rotational angle by one cycle is varied form 0.2*10 $^{-4}$ rad to 9.76* $^{-4}$ rad. This shows that it has the capability of getting very small rotational angle by considering radius of rotor and amplitude of input signal.