• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.43.1-43.1
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• 2018

Spatial distribution of binding state in depth direction is investigated in a hard skin layer on soft polydimethylsiloxane (PDMS) fabricated by Ar ion beam irradiations. The hard skin layer known as a silica-like homogenous layer was composed of two layers. Impinging Ar ions transfer energy to PDMS as a function of collisional energy transfer rate, which is the maximum at surface and decreases gradually as an ion penetrates. This formed the heterogeneous hard skin layer that consists of a top-most layer and an intermediate layer. XPS depth profiling showed the existence of the top-most layer and intermediate layer. In the top-most layer, scission and cross-linking were occurred simultaneously and Si-O bond showed dissociated status, SiOx (x = 1.25 - 1.5). Under the top-most layer, there was the intermediate layer in which cross-linking is mainly occurred and Si-O bond showed silica-like binding status, SiOx (x = 1.75 - 2). And theoretical analysis which calculates the collisional energy transfer and a displacement per atom explained the thickness variation of top-most layer according to Ar ion energy from 360 eV to 840 eV.

• Archives of Reconstructive Microsurgery
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• v.14 no.1
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• pp.37-41
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• 2005

Purpose: The purpose of this study was to evaluate the effectiveness of internal transport using Ilizarov apparatus with free flap surgery for infected tibial nonunion. Materials and Methods: We reviewed 8 patients of infected tibial nonunion treated with internal transport using Ilizarov apparatus and free flap surgery. Seven of eight patients were available for at least 1 year follow-up. All patients were male. The mean age at the time of the surgery was All fractures were Gustilo's type III B open fracture. The mean length of the bone defect was 8.5 cm. All used flaps for covering the soft tissue defect were free rectus abdominis muscle flap. We evaluated bone and functional results with use of the Paley and Catagni's classification. And we classified the complication with use of the Paley's classification. Results: Acceptable length and solid union of bone was achieved in all cases. The mean size of the bone length was 7.2 cm. The mean healing index was 69.5 days/cm. All but one case needed bone graft at docking site. All flaps were survived. There was no recurrence of infection. According to Paley and Catagni's classification, all cases showed excellent or good results. Complications were pin tract infection in 3 cases, persistent pain in 2 cases and limitation of joint motion in 2 cases. Conclusion: Simultaneous free-tissue transfer and Ilizarov distraction osteogenesis was thought to be an attractive treatment modality for infected nonunion of the tibia.

• 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.36 no.2
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• pp.153-160
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• 2009

Purpose: The heterodigital or homodigital artery island flap is a popular method of reconstruction for finger defects. Sometimes, digital artery island flap has some disadvantages such as postoperative flap edema, congestion, and partial necrosis of the flap margin. However, we could decrease these disadvantages by means of venous superdrainage. The aim of this study is to report usefulness and postoperative results of venous supercharging digital artery island flaps for finger reconstruction. Methods: From March of 2005 to March of 2008, a total of eight patients with soft tissue defects of the finger underwent venous supercharging digital island flap transfer. Briefly, the flap is harvested along with dorsal vein that is then anastomosed to a recipient vein in an end - to - end fashion, after flap transfer and insetting. Using this technique, eight patients were operated on, ranging in age 23 to 52 years. Results: All the flaps survived with a success rate of 100 percent, thus fully satisfying the reconstructive requirements. No postoperative flap congestion was recognized, obviating the need to take any measures for venous engorgement, such as suture removal. Among 8 cases, it was possible to make an long - term and follow - up observation more than 6 months. In these cases, the fact that light touches and temperature sensations can be detected in all the flaps. Cold intolerance and hyperesthesia were not seen in our series. Conclusion: Providing good harmony with conventional methods and microsurgery, inclusion of a vein with the heterodigital and homodigital artery island flap allows a more reliable and safer reconstructive choice for finger defects. The venous supercharged island flap is a reliable flap with a consistent arterial structure, and with its augmented venous drainage, it is more reliable, providing single - stage reconstruction of adjacent finger defects, including the fingertip.

• Archives of Plastic Surgery
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• v.37 no.6
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• pp.835-838
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• 2010

Purpose: Reconstruction of soft tissue defects in the distal lower leg, especially in the distal third, largely depends on free tissue transfer and local fasciocutaneous flaps. But several local muscle flaps have also been proposed as useful alternative reconstructive manner. In this report, the authors present the successful use of the flexor digitorum longus muscle flaps in the distal lower leg reconstruction. Methods: Case 1: An 81-year-old woman with a dog bite wound in the left distal lower leg was admitted. She had a $10{\times}8\;cm$ wound with tibial exposure along the medial aspect of the leg. Soft tissue reconstruction with a flexor digitorum longus muscle flap and a split-thickness skin graft was performed. Case 2: A 77-year-old woman had a squamous cell carcinoma in the right distal lower leg. After wide excision, a $5{\times}4\;cm$ wound was developed with exposure of the tibia. The flexor digitorum longus muscle flap was transposed and covered with a split-thickness skin graft. Results: The flexor digitorum longus muscle flaps were shown to be useful to cover tibial defects in the distal lower leg. During the follow-up period, no significant donor site morbidity was found. Conclusion: The flexor digitorum longus muscle flap can be used to cover the exposed distal tibia, especially when a free tissue transfer is not an option. The relative ease of dissection and minimal functional deficits were the major advantages of this flap, while the extent of reach into the lower third has a limitation.

• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.113-122
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• 2006

Although a number of static pile load tests have been performed in this country, re-consideration on the interpretation and loading method is needed, because of their less usefulness in practice. For this study, a static loading testing was performed for a long instrumented PHC pile, which was installed in sand layer overlying thick soft clay. The shaft resistance of the pile had been monitored for a long time after installation, and then the static load testing was performed by the quick load test, unlike the recent Korean practice. Using the measured data, the elastic modulus of pile, residual stress and true resistance on the pile were determined. In the event, it was found that the residual stress on the pile, which remained prior to the static loading, significantly affects the shaft and toe resistances. Also, it was realized that the setup effect for the long pile is significant.

• Archives of Plastic Surgery
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• v.39 no.2
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• pp.138-142
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• 2012

Background : Electrical burns are one of the most devastating types of injuries, and can be characterized by the conduction of electric current through the deeper soft tissue such as vessels, nerves, muscles, and bones. For that reason, the extent of an electric burn is very frequently underestimated on initial impression. Methods : From July 1999 to June 2006, we performed 15 cases of toe tissue transfer for the reconstruction of finger defects caused by electrical burns. We performed preoperative range of motion exercise, early excision, and coverage of the digital defect with toe tissue transfer. Results : We obtained satisfactory results in both functional and aesthetic aspects in all 15 cases without specific complications. Static two-point discrimination results in the transferred toe cases ranged from 8 to 11 mm, with an average of 9.5 mm. The mean range of motion of the transferred toe was $20^{\circ}$ to $36^{\circ}$ in the distal interphalangeal joint, $16^{\circ}$ to $45^{\circ}$ in the proximal interphalangeal joint, and $15^{\circ}$ to $35^{\circ}$ in the metacarpophalangeal joint. All of the patients were relatively satisfied with the function and appearance of their new digits. Conclusions : The strategic management of electrical injury to the hands can be both challenging and complex. Because the optimal surgical method is free tissue transfer, maintenance of vascular integrity among various physiological changes works as a determining factor for the postoperative outcome following the reconstruction.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.167-180
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• 2019

Friction piles are being constructed in Southeast Asia (Myanmar, Cambodia, Vietnam, etc.) where the soft ground is deep, and many cases of friction piles are accumulated in terms of experience. In this study, we used the results of four static load test and load transfer test conducted in Myanmar sites to analyze the skin friction of soil layer. In addition, we proposed a relationship chart with skin friction measured in the N-value of Standard Penetration Test (SPT) and the load transfer test result of the single drilled shaft. In the case of Myanmar sites, the range of soil layers was deeper than domestic sites, so the conventional formula of skin friction using the N-value of SPT is different from domestic sites. In sandy layer, fs = 0.096 N in Myanmar sites showed a similar result of the domestic fs = 0.106 N. In clayey layer, fs = 0.315 N, in Myanmar sites showed about 5.0 times higher than the domestic fs = 0.062 N. The results of this study are based on limited data. Therefore, if we analyze the results of more load transfer tests, we can suggest a conventional formula for skin friction according to the N-value. It is expected to be used as important basic data in the future.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.7
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• pp.511-515
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• 2012

A road energy harvester was designed and fabricated to convert mechanical energy from the vehicle load to electrical energy. The road energy harvester is composed of 24 piezoelectric cantilevers and a vehicle load transfer mechanism. Applying a vehicle load transfer mechanism rather than directly installing energy harvesters under roads decreases the area of road construction and allows more energy harvesters to be installed on the side of the road. The power generation amount with respect to the vehicular velocity change was assessed by installing the vehicle load transfer mechanism and the energy harvester in the form of speed bumps and underground. The energy harvester installed in a speed bump form generated power of 7.61 mW at the vehicular velocity of 20 km/h. Also, power generation of the energy harvester installed in the underground form was 63.9 mW at the vehicular velocity of 28 km/h. Although the number of piezoelectric cantilevers was reduced by 1/3 to 24 in comparison to the previous research results with 72 piezoelectric cantilevers, similar power generation characteristic value was obtained within the vehicular velocity of 20 km/h by altering the vehicle load transfer mechanism and cantilever vibration method.

• Journal of the Korean Society of Clothing and Textiles
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• v.11 no.1
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• pp.79-85
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• 1987

The purpose of this study was to help the consumer about the care of nonwoven fabrics by investigation of the properties such as launderability. shrinkage, color fastness and strenth. Materials used were two types, soft and stiff, of commercial nonwoven fabrics. Deter-gents used were neutral detergents, synthetic detergents and dry cleaning solutions(perch-toro-ethylene) The results of this study were summerized as follows; 1. Laundering of nonwoven fabrics in low temperature is more ideal as morphological changes by laundering in high temperature were more prominent than that in low temperature. 2. Ironing of nonwoven fabrics wants more attention on environmental temperature as the rate of shrinkage in high temperature was higher than that in low temperature. Neutral detergents are more desirable as the rate of shrinkage of nonwoven fabrics by laundering with synthetic detergents was more prominent than that with neutral deter-gents. The rate of shringkage of nonwoven fabrics was not affected by dry cleanining. 3. Special care is wanted in order to prevent color transfer from non woven fabrics to polyester or wool during dry cleaning or laundering as the color fastness test show that color changes of nonwoven fabrics were not affected, but that color stain was increased on polyester or wool. 4. The strength was affected by composition of fibers and types of nonwoven fabrics, soft or stiff.