• Journal of Welding and Joining
• /
• 제15권6호
• /
• pp.32-40
• /
• 1997

Solid state diffusion bonding is the joining process performed by creep and diffusion, which is accelerated by heating below melting temperature and proper pressing, in vacuum or shielding gas atmosphere. By this process we can obtain sufficient joint which can't be expected from the fusion welding. For Ti-6Al-4V alloy, the optimum solid state diffusion bonding condition and mechanical properties of the joint were found, and micro void morphology at bond interface was observed by SEM. The results of tensile test showed sufficient joint, whose mechanical properties are similar to that of base metal. 850$^{\circ}$C, 3MPa is considered as the optimum bonding condition. Void morphology at interface is long and flat at the initial stage. As the percentage of bonded area increases, however, small and round voids are found. Variation of void shape can be explained as follows. As for the void shrinkage mechanism, at the initial stage, power law creep is the dominant, but diffusion mechanism is dominant when the percentage of bonded area is increased.

• Journal of Oral Medicine and Pain
• /
• 제25권1호
• /
• pp.63-71
• /
• 2000

The authors assessed if there is a relationship between joint effusion and the presence of pain, and between joint effusion and disc displacement in 446 temporomandibular joints of 223 subjects who visited the Department of Oral Medicine, Kyungpook National University Hospital with the complaints of temporomandibular joint problem. The amount of joint effusion and the position of disc were determined from magnetic resonance images of the temporomandibular joints. The position of disc was classified into normal disc position, disc displacement with reduction (DDWR), and disc displacement without reduction (DDWOR). The amount of joint effusion was graded according to the extent of joint area of high signal intensity on T2-weighted MR images. These findings were correlated with one another and statistically analyzed. The results were as follows; 1. The incidence of temporomandibular joint pain Was higher in the joints with higher amount of joint effusion (P<0.001). 2. The proportion of temporomandibular joints with higher amount of effusion increased in the joints with more advanced articular disc displacement (P<0.001).

• 대한물리의학회지
• /
• 제5권1호
• /
• pp.53-61
• /
• 2010

Purpose : The purpose of this study is to compare the distribution of foot pressure, knee and ankle joint angle between treadmill walking and ground walking in normal person. Methods : 18 Person of subject has participated this study, let subject to walk in ground and treadmill in order to gain data of foot distribution and knee, ankle joint angle using by parotec system. and Dartfish system. Walking velocity was constrained by 2Km/h and more 10sec. Date analysis was used by paired-t test using SPSS/PC statistical programs for window. Results : Result show that total contact times has shown symmetry between both legs, and more increase of left foot pressure in treadmill walking. Foot pressure of treadmill walking was significantly decreased in right hind foot and fore foot and hallux area. The ankle joint angle of treadmill walking was significantly decreased in initial contact phase. Conclusion : Results of this study show that foot pressure of treadmill walking was more decreased than ground walking in right hind foot and fore foot, hallux area. And the ankle joint angle of treadmill walking was significantly decreased in initial contact phase.

• 근관절건강학회지
• /
• 제17권1호
• /
• pp.68-78
• /
• 2010

Purpose: This study was conducted to determine the effects of Tai-Chi exercise and self-help management program applying laughter therapy in patients with osteoarthritis. Methods: This quasi-experimental study recruited a sample of 61 patients with osteoarthritis (experimental group: 30, control group: 31) through the community healthcare centers located in Seoul and Kyung Gi area. The primary outcome measures included symptoms of osteoarthritis, basic physical performance, fatigue, and depression assessed before and after the study. The data were analyzed using SPSSWIN V. 12.0. Results: At the end of the six-week intervention, left shoulder flexibility (t=2.011, p=.049), 6m walking speed (t=3.639, p=.001), and right balance (t=-2.30, p=.025) were significantly improved in the control group. Fatigue (t=3.012, p=.004), stiffness (t=2,093, p=.041), right shoulder flexibility (t=2.138, p=.037), right balance (t=-2.065, p=.043), and 6m walking speed (t=2.683, p=.009) were significantly improved in the experimental group. Conclusion: A twice a week, 6-week tai-chi exercise self-help management program applying laughter therapy is effective in decreasing fatigue and stiffness. Osteoarthritis is one of common chronic diseases that the patients should be required to continue self management for the rest of their life. Therefore, there is a need to develop the more effective self-help management program and nursing intervention to motivate them to maintain their own self-help management.

• 국제학술발표논문집
• /
• The 2th International Conference on Construction Engineering and Project Management
• /
• pp.749-758
• /
• 2007

Learning has become an important aspect for any organization to stay relevant and competitive in the corporate world of survival. In construction industry, the international construction joint ventures (ICJVs) provide an excellent platform with opportunity of learning among partners seeking to develop new area of competency and improve their overall competitiveness for their next project endeavor. This paper discusses the development of a conceptual model of effective learning in ICJVs using four major stages of development in a typical joint venture (JV) 's process. The study identified that there are three key constructs that contribute to effective learning comprising learning conditions in the JV's pre-inception stage, success factors of JV for learning in the forming & organizing stage, and learning actions in the implementation & adjustment stage. The effective learning outcomes are measured by the characteristics of learning organization during the JV's completion & evaluation stage. Details and issues of each stage and the methodology of research will be presented and discussed.

• Steel and Composite Structures
• /
• 제24권5호
• /
• pp.615-633
• /
• 2017

Fatigue crack initiated in welded tubular joints due to cyclic loading may produce harmful effect on the integrity of the tubular structures. To study such effect, both fatigue and static tests on nine circular tubular T-joint specimens made of carbon steel materials were carried out. The specimens were subjected to tensile loading in both fatigue and static tests. The load-displacement relation, the crack propagation and the failure mode of the specimens are all analyzed. The deterioration of the static strength of the cracked T-joints is also investigated and evaluated through an area reduction factor. Experimental results indicate that the static strength of a tubular T-joint with a surface crack seems to decrease slightly while a through crack has relatively remarkable effect on the reduction of the static strength. Additionally, experimental results also show that the toughness of the materials and the geometry of the specimens play an important role on the failure process of cracked tubular T-joints.

• Steel and Composite Structures
• /
• 제21권5호
• /
• pp.1017-1029
• /
• 2016

When a welded circular hollow section (CHS) tubular joint is subjected to brace axial loading, failure position is located usually at the weld toe on the chord surface due to the weak flexural stiffness of the thin-walled chord. The failure mode is local yielding or buckling in most cases for a tubular joint subjected to axial load at the brace end. Especially when a cyclic axial load is applied, fracture failure at the weld toe may occur because both high stress concentration and welding residual stress along the brace/chord intersection cause the material in this region to become brittle. To improve the ductility as well as to increase the static strength, a tubular joint can be reinforced by increasing the chord thickness locally near the brace/chord intersection. Both experimental investigation and finite element analysis have been carried out to study the hysteretic behaviour of the reinforced tubular joint. In the experimental study, the hysteretic performance of two full-scale circular tubular T-joints subjected to cyclic load in the axial direction of the brace was investigated. The two specimens include a reinforced specimen by increasing the wall thickness of the chord locally at the brace/chord intersection and a corresponding un-reinforced specimen. The hysteretic loops are obtained from the measured load-displacement curves. Based on the hysteretic curves, it is found that the reinforced specimen is more ductile than the un-reinforced one because no fracture failure is observed after experiencing similar loading cycles. The area enclosed by the hysteretic curves of the reinforced specimen is much bigger, which shows that more energy can be dissipated by the reinforced specimen to indicate the advantage of the reinforcing method in resisting seismic action. Additionally, finite element analysis is carried out to study the effect of the thickness and the length of the reinforced chord segment on the hysteretic behaviour of CHS tubular T-joints. The optimized reinforcing method is recommended for design purposes.

• 대한골관절종양학회지
• /
• 제13권1호
• /
• pp.55-59
• /
• 2007

활액막 연골종은 관절의 활액막에서 결체조직의 화생에 의해 연골 조직이 형성되는 질환이며 드물게 건초, 활액낭에 발생하는 경우도 있다. 정확한 발생 기전은 아직 밝혀지지 않았으나 외상, 감염 등이 원인으로 제시되고 있으며 관절 연골을 구성하던 연골의 일부가 떨어져 나와 활액막내로 흡수되어 연골성 화생을 일으킨다는 가설이 유력하다. 주로 슬관절에 발생하며 그 외 견관절, 주관절, 고관절 등에서 발생하는 것으로 알려져 있다. 65세 남자가 약 6개월 간의 우측 주관절 동통, 주관절 구축 및 우측 제1수지와 완관절의 신전 장애 및 감각 저하를 주소로 내원 하였다. 단순 방사선 검사상 주관절의 관절 간격이 좁아져 있었고 관절면의 가장 자리에 골극이 형성되어 있었으며 연골하골은 경화소견이 관찰되었다. 자기 공명 영상 검사상 요골두 직하방 전외측에 약 $16{\times}12$ mm 크기의 원형의 종양이 관찰되었으며, T1 강조 영상에서 균질의 저신호 강도, T2 강조 영상에서 고신호 강도와 저신호 강도가 혼재되어 있었다. 종양 절제술을 시행하였으며 수술소견상 종양에 의해 요골신경이 압박되어있는 소견이 관찰되었다. 절제한 종양은 조직소견상 활액막 연골종으로 진단되었다.

• 근관절건강학회지
• /
• 제14권2호
• /
• pp.149-157
• /
• 2007

Purpose: The purpose of this study was to identify the effect of BeHaS exercise program on the upper body function(muscle strength, muscle endurance, flexibility) in middle-aged women. Method: Middle-aged women were recruited in the community the study was conducted from August 2005 to December 2005. Twenty-two experimental subjects were selected from P area, eighteen control subjects were selected from A area. The experimental group carried out the program two times a week for 12 weeks. Muscle strength(grip strength, pinch strength), muscle endurance (push-up), flexibility were measured. Data were analyzed with $x^2$-test, t-test, and ANCOVA using SPSS WIN 11.5. Results: 1) Left grip strength and right pinch strength of the experimental group were significant differences after the BeHaS exercise program. 2)Muscle endurance of the experimental group(t=3.14, p=0.015) was significant difference after the BeHaS exercise program. 3) Left and right flexibility showed no significant differences after the BeHaS exercise program. Conclusion: The results suggest that BeHaS exercise program would partially improve upper body function of middle-aged women. Further studies are necessary in order to determine the effects of flexibility after BeHaS exercise program.

• Smart Structures and Systems
• /
• 제5권4호
• /
• pp.329-344
• /
• 2009

Ultrasonic chaotic excitations combined with sensor prediction algorithms have shown the ability to identify incipient damage (loss of preload) in a bolted joint. In this study we examine a physical experiment on a single-bolt aluminum lap joint as well as a three-dimensional physics-based simulation designed to model the behavior of guided ultrasonic waves through a similarly configured joint. A multiple bolt frame structure is also experimentally examined. In the physical experiment each signal is imparted to the structure through a macro-fiber composite (MFC) patch on one side of the lap joint and sensed using an equivalent MFC patch on the opposite side of the joint. The model applies the waveform via direct nodal displacement and 'senses' the resulting displacement using an average of the nodal strain over an area equivalent to the MFC patch. A novel statistical classification feature is developed from information theory concepts of cross-prediction and interdependence. This damage detection algorithm is used to evaluate multiple damage levels and locations.