• Korean Journal of Head & Neck Oncology
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• v.35 no.1
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• pp.1-11
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• 2019

In head and neck reconstruction, microsurgeons are faced with various demands, such as thin resurfacing, or three-dimensional reconstruction, and therefore, conventional flap as well as perforator flaps are all useful for the functional and aesthetic reconstruction successfully. Among perforator flaps, the pros and cons of anterolateral thigh perforator flap(ALTp) and thoracodorsal perforator flap(TAp) is compared and selected depending on the surgeon's preference, recipient site condition or patient status. Both flaps can be elevated in a chimeric pattern by combining different aspects of tissue components. Customized or tailored reconstruction as well as 3 dimensional reconstructions are all available with perforator flaps and it is useful in head and neck reconstruction. The most outstanding update in head and neck reconstruction is the perforator based island flap (PBIF) compared to conventional flaps. The conventional local flap has evolved on behalf of the perforator concept and its design becomes more flexible and freestyle with less limitations. Actually, random pattern flap is now a misnomer and most conventional local flaps turn into PBIFs. Finally we can say all conventional donor site becomes universal, depending on the surgeons' preference or idea. Moreover, there is no more "flap of choice" and postoperative results are quite variable by surgeons' ability. Operative procedures and plans are very flexible to freestyle flap. With all these advantages, surgeons should be armed with both conventional and perforator concepts for solving any defects or problems.

• Archives of Plastic Surgery
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• v.38 no.3
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• pp.235-240
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• 2011

Purpose: Management of pressure sores has been improved, along with development of musculocutaneous flaps and perforator flaps. Nowadays, the treatment of pressure sore with perforator flaps has shown several advantages, including minimal donor site morbidity, relatively versatile flap design not only in primary cases but also in recurred cases and minimized anatomical rearrangement of regional muscle position. In this study, we report our clinical experience of gluteal perforator flap used in the treatment of a greater trochanteric pressure sore. Methods: A clinical study was performed on 7 patients who underwent total 10 operations. 1 superior gluteal artery perforator flap and 9 inferior gluteal artery perforator flaps were used to reconstruct the defect, followed by the mean observation duration of 22 months. Results: There were no total flap loss. We treated 2 cases of partial flap loss with debridement and primary repair. 2 recurred cases were successfully treated using the same method. Donor sites were all primarily repaired. Conclusion: The gluteal perforator flap could be considered as a safe and favorable alternative in the treatment of soft tissue defects in the greater trochanteric area. The advantages of the flap include low donor site morbidity and the possibility of versatile flap design not only in primary cases but also in recurred cases.

• Smart Structures and Systems
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• v.16 no.3
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• pp.555-577
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• 2015

In the work at hand, the development of a morphing flap, actuated through shape memory alloy load bearing elements, is described. Moving from aerodynamic specifications, prescribing the morphed shape enhancing the aerodynamic efficiency of the flap, a suitable actuation architecture was identified, able to affect the curvature. Each rib of the flap was split into three elastic elements, namely "cells", connected each others in serial way and providing the bending stiffness to the structure. The edges of each cell are linked to SMA elements, whose contraction induces rotation onto the cell itself with an increase of the local curvature of the flap airfoil. The cells are made of two metallic plates crossing each others to form a characteristic "X" configuration; a good flexibility and an acceptable stress concentration level was obtained non connecting the plates onto the crossing zone. After identifying the main design parameters of the structure (i.e. plates relative angle, thickness and depth, SMA length, cross section and connections to the cell) an optimization was performed, with the scope of enhancing the achievable rotation of the cell, its ability in absorbing the external aerodynamic loads and, at the same time, containing the stress level and the weight. The conceptual scheme of the architecture was then reinterpreted in view of a practical realization of the prototype. Implementation issues (SMA - cells connection and cells relative rotation to compensate the impressed inflection assuring the SMA pre-load) were considered. Through a detailed FE model the prototype morphing performance were investigated in presence of the most severe load conditions.

• Advances in aircraft and spacecraft science
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• v.4 no.5
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• pp.503-514
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• 2017

The attitude control of an aircraft is usually fulfilled by means of thrusters at high altitudes. Therefore, the possibility of using also aerodynamic surfaces would produce the advantage of reducing the amount of fuel for the thrusters to be loaded on board. For this purpose, Zuppardi already considered some aerodynamic problems linked to the use of a wing flap in a previous paper. A NACA 0010 airfoil with a trailing edge flap of 35% of the chord, in the range of angle of attack 0-40 deg and flap deflections up to 30 deg was investigated. Computer tests were carried out in hypersonic, rarefied flow by a direct simulation Monte Carlo code at the altitudes of 65 and 85 km of Earth Atmosphere. The present work continues this subject, considering the same airfoil and free stream conditions but two flap extensions of 45% and 25% of the chord and two flap deflections of 15 and 30 deg. The main purpose is to compare the influence of the flap dimension with that of the flap deflection. The present analysis is carried out in terms of: 1) percentage variation of the global aerodynamic coefficients with respect to the no-flap configuration, 2) increment of pressure and heat flux on the airfoil lower surface due to the Shock Wave-Shock Wave Interaction (SWSWI) with respect to the same quantities with no SWSWI or in no-flap configuration, 3) flap hinge moment. Issues 2) and 3) are important for the design of the mechanical and thermal protection system and of the flap actuator, respectively. Under the above mentioned test and geometrical conditions, the flap deflection is aerodynamically more effective than the flap extension, because it involves higher variation of the aerodynamic coefficients. However, tests verify that a smaller deflection angle involves the advantage of a smaller increment of pressure and heat flux on the airfoil lower surface, due to SWSWI, as well as a smaller hinge moment.

• Archives of Plastic Surgery
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• v.35 no.2
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• pp.208-213
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• 2008

Purpose: Distally based superficial sural artery island flap has some disadvantages such as postoperative flap edema, congestion, and partial necrosis of the flap margin. Venous congestion is an area of considerable concern in distally based superficial sural artery fasciocutaneous flap and is one of the main reasons for failure, particularly when a large flap is needed. However, we could decrease these disadvantages by means of venous superdrainage. Methods: From June of 2006 to June of 2007, a total of two patients with soft tissue defects of lower one third of the leg underwent venous supercharging distally based superficial sural artery island flap transfer. The distal pivot point of this flap was designed at septocutaneous perforator from the peroneal artery of the posterolateral septum, which was 5 cm above the tip of the lateral malleolus. Briefly, this technique is performed by anastomosing the proximal end of the lesser saphenous vein and collateral vein to any vein in the area of the recipient defect site. Results: No venous congestion was noted in any of the two cases. No other recipient or donor-site complications were observed, except for minor wound dehiscence in one case. In 3 to 6 months follow-up, patients had minor complaints about lack of sensation in the lateral dorsal foot. Conclusion: The peroneal artery perforator is predictable and reliable for the design of a distally based superficial sural artery island flap. Elevation of the venous supercharging flap is safe, easy, and less time consuming. In conclusion, the venous supercharging distally based superficial sural artery island flap offers an alterative to free tissue transfer for reconstruction of the lower extremity.

• Archives of Plastic Surgery
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• v.46 no.5
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• pp.480-483
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• 2019

Repairing surgical defects of the nose is still challenging due to its tridimensional shape and its aesthetic concern. Difficulty in reconstructing nasal subunits lies in their contour, skin texture and limited availability of adjacent skin. For lower nasal dorsum and supra-tip regions, we design a new combined local flap as existing local flaps may give disappointing results. This combination flap was performed on two patients for reconstruction of the lower nasal dorsum area after basal cell carcinoma excision. Size of the excision ranged from 20 to 25 mm diameter and safe margins were obtained. The defects were reconstructed with a local flap that combined a rotation nasal flank flap and a V-Y advancement nasolabial flap. Excision and reconstruction were performed in a one-stage surgery under intravenous sedation and local anesthesia. There were no postoperative complications and no flap loss occurred. Aesthetic and functional results after 6 months postoperatively were satisfying without modification of nasal shape. This flap is reliable and offers interesting functional and aesthetic outcomes. It can be considered as a new reconstruction alternative for supra-tip and lower nasal dorsum skin defects performed in a one-stage procedure under local anesthesia.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.165-171
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• 2004

Smart UAV, which adopting tiltrotor aircraft concept, requires long endurance and high speed capability simultaneously These two contradictable flight performances are hard to meet with single wing concept and inevitably require the operation of flap system which should reveal optimal performance for each flight mode. In order to design SUAV flaperon satisfying the performance requirement, various configurations are generated and their aerodynamic performances are analyzed using numerical flow computations around flaps. Considering aerodynamic performance and manufacturing simplicity, a final flap configuration is selected.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.58-62
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• 2001

A numerical investigation was performed to determine the effect of airfoil on the optimum flap. height using NACA 0006, 0009, 0012, 0015, 0018, 0021 and 0024 airfoils. The six flaps which have 0.5% chord height difference were used. A Navier-Stokes code, FLUENT, was used to calculate the flow field of the airfoil. The code was first tested as a benchmark by modelling flow around a NACA 4412 airfoil. Predictions of local pressure coefficients are found to be in good agreement with the result of the experimental result. For every NACA 00XX airfoil, flap heights ranging from 0.0% to 2.5% chord were changed by 0.5% chord interval and their effects were also studied. Representative results from each case are presented graphically and discussed. It is concluded that this initial approach gives a promise for the future development of wind turbine optimum design.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.3
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• pp.1-9
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• 2011

In this paper, a conceptual design process for Very Light Jet aircraft has been proposed incorporating aircraft safety certification. During the proposed design process, satisfaction of the airworthiness certification for an intermediate resulting aircraft configuration is evaluated and then redesigns are carried out if necessary and until the designed aircraft configuration satisfies the airworthiness requirements. Certification database has been developed using FAR 23, AC 23, KAS 23, and CS 23 as the airworthiness certification. Based on the developed certification database Design Certifcation Related Table has been produced to use the airworthiness requirements as design constraints in the propsed design process. Using Quality Function Deployment the design variables for a redesign are carefully selected and a design optimization is performed. To demonstrate the feasibility and effectiveness of rapid aircraft conceptual design using the proposed approach, a Very Light Jet design optimization including a redesign of wing flap has been performed and the design results have been presented.

• Archives of Plastic Surgery
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• v.34 no.4
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• pp.441-447
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• 2007

Purpose: Various kinds of local flap or free flap have been used for coverage for soft tissue defects with bone exposure over the ankle and dorsum of foot. Adipofascial flaps, nourished by vascular plexuses of the subcutaneous tissue and deep fascia originating from the local perforators of the major vessels, appear particularly to be indicated for the reconstruction of these areas. Our experience with this flap on the dorsum of foot and ankle has also been quite encouraging. Methods: The design of the flap is determined by the size and the location of the defect. The base of the flap is chosen depending on the availability of the soft tissue around the defect. The ratio of the area of the flap to the area of the base wound be more reliable to predict the survival of the turnover flap by the conventional length-to-width ratio. Nineteen patients with defect over the dorsum of the foot and ankle were resurfaced with adipofascial turn-over flaps and skin graft. Results: The average age of the patients was 38.2 years(3 - 81 years). The flap size was from $2{\times}3cm$ to $8{\times}5cm$. The average follow-up time was 6 months. All flaps survived completely except one case who suffered distal necrosis of the flap. The additional skin graft was required for partial skin loss in the five cases. Other functional impairment was not noted. Conclusion: Dissection of the local adipofascial turnover flap is quite easy, quick, requires less time and sacrifice of surrounding muscle itself, and maintains major arteries. In most cases, donor-site morbidity is minimal with an acceptable scar, and both functional and esthetical results were satisfactory. Therefore, Adipofascial flap could be an option for the difficult wounds around the foot and ankle.