• Journal of Korean Foot and Ankle Society
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• v.26 no.2
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• pp.95-102
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• 2022

Purpose: This study was based on the Korean Foot and Ankle Society (KFAS) member survey and aimed to report the current trends in the management of syndesmotic injuries over the last few decades. Materials and Methods: A web-based questionnaire containing 36 questions was sent to all KFAS members in September 2021. The questions were mainly related to the preferred techniques and clinical experiences in the treatment of patients with syndesmotic injuries. Answers with a prevalence ≥50% of respondents were considered a tendency. Results: Seventy-six (13.8%) of the 550 members responded to the survey. The results showed that the most preferred method to diagnose a syndesmotic injury was magnetic resonance imaging (MRI). Intraoperatively, the external rotation stress test and the Cotton test were most frequently used to confirm syndesmotic diastasis. The reduction was usually done by a reduction clamp. One 3.5-mm screw was used most frequently over three cortices at 2~4 cm above the ankle joint. The preferred ankle position during fixation was 0° dorsiflexion. Removal of the syndesmotic screw was routinely done by most surgeons, mainly because of the limitation of movement and risk of screw breakage. Factors that affect suture button selection included non-rigid fixation which enables adequate fixation, early weight-bearing, and an infrequent need to remove the hardware. Inadequate reduction was considered the main factor that affects poor prognosis. Conclusion: This study proposes updated information about the current trends in the management of syndesmotic injuries in Korea. Consensuses in both the diagnostic and therapeutic approach to patients with syndesmotic injury were identified in this survey study. This study may raise the awareness of the various possible approaches toward the injury and should be used to further establish a standard protocol for the management of syndesmotic injuries.

• Journal of Korean Foot and Ankle Society
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• v.13 no.1
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• pp.23-27
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• 2009

Purpose: The purpose of this study was to evaluate the clinical outcome of neglected Achilles tendon rupture treated with reconstruction and augmentation with flexor hallucis longus (FHL) tendon using one incision technique. Materials and Methods: Between July 2006 and March 2008, eleven patients with neglected Achilles tendon rupture received surgical treatment. Through one incision technique, augmentation with auto FHL tendon transfer was performed using a Bio-Interference screw (Arthrex, Naples, FL) and followed by V-Y advancement (5 cases) or gastronemius fascial turn-down flap procedure (6 cases). After mean follow up of 20.7 months (range, 11.8-33.3 weeks), clinical outcomes were evaluated with Visual Analogue Scale (VAS), American Orthopedic Foot and Ankle Society (AOFAS) score, 10 repetitive double heel raise test, 10 repetitive single heel raise test and subjective satisfaction. Results: The length of the gap after debridement was $5.4{\pm}2.0$ cm. The VAS improved from $4.1{\pm}0.9$ to $1.5{\pm}0.8$ at last follow up (p<0.05). The AOFAS score increased from $38.9{\pm}12.2$ to $91.5{\pm}8.9$ at last follow up (p<0.05). Eight patients were satisfied with excellent results and three were satisfied with good results. All patients were able to perform 10 repetitive double heel raise and nine out of eleven patients were able to perform 10 repetitive single heel raise at last follow up. There were no complications including deep infection or re-rupture. Conclusion: Augmentation with FHL tendon transfer and reconstruction with V-Y advancement or turn-down flap through one incision technique appeared to be effective and safe. This technique is recommendable for the treatment of neglected Achilles tendon rupture.

• Journal of Korean Association for Spatial Structures
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• v.20 no.2
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• pp.39-49
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• 2020

In this study, we will develop a hybrid cross-sectional shape of steel inserted type glued-laminated timber that can improve the strength of structural glued-laminated timber and maximize the ductility by using steel plate with excellent tensile and deformation ability. A total of three specimens were fabricated and the flexural performance test was carried out to evaluate the structural performance of the steel inserted type glued-laminated timber. In order to compare the effect of steel inserted glued-laminated timber, one structural glued-laminated timber test specimen composed of pure wood was manufactured. In addition, in order to evaluate the adhesion performance of the steel inserted, one each of a screw joint test specimen and a polyurethane joint test specimen was prepared. As a result, all the specimens showed the initial crack in the finger joint near the force point. This has been shown to be a cause of crack diffusion and strength degradation. The use of finger joints in the maximum moment section is considered to affect the strength and ductility of the glued-laminated timber beam. Polyurethane-adhesive steel inserted glued-laminated timber showed fully-composite behavior with little horizontal separation between the steel plate and glued-laminated timber until the maximum load was reached. This method has been shown to exhibit sufficient retention bending performance.

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.3
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• pp.20-24
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• 2006

Air balancer is a conveyance cargo-handling machine, used in assembly and process lines of car and machining industries. This can lift up an object, the weight of which is from 5 to 200 kg, and moves it to a position. As industrial technologies evolve, it is required to move an object and fit it into a specified position with greater accuracy, rather than performing simple tasks such as lifting objects up and down as conventional ones do. There is also a demand to handle an object with one hand, rather than with two hands,. Through designs of manifold unit for an air balancer function, pilot regulator unit to keep pressure constant, hand unit for an accurate load perception function, and air balancer circuit, this study enables everybody to work it with ease and convenience. Experiments and comparisons were conducted for the performance evaluation of the circuit.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.2
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• pp.3-9
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• 2006

HSM(High-speed Machining) is widely used in rapid manufacturing of precision products and molds of various materials. Improvement in cutting efficiency is one of the important subjects in the HSM process. To analyse the dynamic behavior during a very short cutting time, the computational analysis code, LS-DYNA3D, was employed for the simulation of the mechanism of HSM for aluminium 7075. This cutting mechanism includes some difficult points in simulation, for example, material and geometrical non-linearity, high-speed dynamic impact, contact with friction, etc. In this paper, a finite element model considering the strain rate effect is proposed to predict the cutting phenomena such as chip deformation, strain and stress distributions, which will help us to design the HSM process.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.726-733
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• 2000

In this article, we introduce a practical case study of the structural design improvement for a vertical machining center. During test operations, it have experienced excessive deflections and vibrations due to the fluctuating forces generated by the ball-screw thrust motor. At first we did investigate where and how much deflections and vibrations had been brought about on it. Next we made some possible structural design alternatives. It is a matter of course to compare finite element static and dynamic analysis results of both the original design and alternatives. Fortunately we have been able to find out a good one among those alternatives.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.5
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• pp.21-26
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• 2005

It is important to measure the rotational accuracy of NC lathe spindle as it affects to the qualities of all machines machined by the NC lathe using in industries. The bad rotational accuracy of NC lathe spindle are caused mainly by wearness of the spindle in using and quality of spindle when machining and using low level bearings. It occurs especially in case of NC lathes because the cutting force acting to work-piece act on one side to the spindle not to both sides symmetrically. Therefore in this study, constructing experimental appratus for measuring of rotational accuracy by using eddy current type gap sensors, converters, screw terminal, data acquisition board inserted in computer and software f3r data acquisition, DT VEE ver. 5.0 and then error data acquired in the rotational accuracy test of NC lathe spindle are analysed in plots and statistical treatments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.337-341
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• 2002

In these day, micro systems have gained attention with development of advance technologies. Researches about the fabrication of micro parts are actively made in the whole world. Among the researches, technology for micro injection molding machine is one of the key issues for fabrication of micro parts. In this study, we developed a micro injection molding machine for micro parts. To achieve this, injection unit was constructed using a screw with diameter of 12 mm. Clamping unit with clamping force of 1.75 kgf/$\textrm{cm}^2$ was constructed. Also verification test fur fabrication of micro parts was performed. It was performed that the micro injection molding machine can fabricate micro parts based on the result.

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.171-177
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• 2013

Purpose: The purpose of this study was to compare the efficacy of two imaging modes in a cone beam computed tomography (CBCT) system in detecting root fracture in endodontically-treated teeth with fiber posts or screw posts by selecting two fields of view. Materials and Methods: In this study, 78 endodontically-treated single canal premolars were included. A post space was created in all of them. Then the teeth were randomly set in one of 6 artificial dental arches. In 39 of the 78 teeth set in the 6 dental arches, a root fracture was intentionally created. Next, a fiber post and a screw post were cemented into 26 teeth having equal the root fractures. High resolution (HiRes) and standard zoom images were provided by a CBCT device. Upon considering the reconstructed images, two observers in agreement with each other confirmed the presence or absence of root fracture. A McNemar test was used for comparing the results of the two modes. Results: The frequency of making a correct diagnosis using the HiRes zoom imaging mode was 71.8% and in standard zoom was 59%. The overall sensitivity and specificity in diagnosing root fracture in the HiRes mode were 71.79% and 46.15% and in the standard zoom modes were 58.97% and 33.33%, respectively. Conclusion: There were no significant differences between the diagnostic values of the two imaging modes used in the diagnosis of root fracture or in the presence of root canal restorations. In both modes, the most true-positive results were reported in the post space group.

• The Journal of Advanced Prosthodontics
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• v.12 no.5
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• pp.307-315
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• 2020

PURPOSE. The purpose of this study was to evaluate the occurrence of displacement while tightening the screw of scan bodies, which were compared according to the material type. MATERIALS AND METHODS. Three types of scan bodies whose base regions were made up of polyether ether ketone (PEEK) material [Straumann Group, Dentium Group, and Myfit (PEEK) Group] and another scan body whose base region was made up of titanium material [Myfit (Metal) Group] were used (15 per group). The reference model was fabricated by aligning the scan body library on the central axis of the implant, and moving this position by the resin model. The screws of the scan bodies were tightened to the implant fixture with torques of 5 Ncm, 10 Ncm, and a hand tightening torque. After the application of the torque, the scan bodies were scanned using a laboratory scanner. To evaluate the vertical, horizontal, and 3-dimensional (3D) displacements, a 3D inspection software program was used. To examine the difference among groups, one-way analysis of variance and Tukey's HSD post hoc test were used (α=.05). RESULTS. There were significant differences in 3D, vertical, and horizontal displacements among the different types of scan bodies (P<.001). There was a significantly lower displacement in the Straumann group than in the Myfit (PEEK) and Dentium groups (P<.05). CONCLUSION. The horizontal displacement in all groups was less than 10 ㎛. With the hand tightening torque, a high vertical displacement of over 100 ㎛ occurred in PEEK scan bodies (Myfit and Dentium). Therefore, it is recommended to apply a tightening torque of 5 Ncm instead of a hand tightening torque.