• Journal of the Korean Society of Industry Convergence
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• v.22 no.4
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• pp.387-394
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• 2019

This paper presents an analytical study on the strength and stiffness of various types of truss structures. The applied models are triangular-like opened truss-wall triangular model (OTT), closed truss-wall triangular model (CTT), opened solid-wall triangular model (OST), and hypercube models defined as core-filled or core-spaced cube. The models are analyzed by numerical model analysis using DEFORM 2D/3D tool with AISI 304 stainless steel. Then, the ideal solutions for stiffness and strength are defined. Finally, the relative elastic modulus of the core-spaced model is obtained as 0.0009, which is correlated with the cancellous bone for the relative density range of 0.029-0.03, and the relative elastic modulus for the core-filled model is obtained as 0.0015, which is correlated with cancellous bone for the relative density range of 0.035-0.036. For the relative compressive yield strength, the OTT reasonably agrees with the cancellous bone for the relative density of 0.042 and the relative compressive strength of 0.05. The CTT and OST are in good agreement at the relative density of 0.013 and the relative compressive yield strength of 0.002. The hypercube models can be used for the cancellous bone for stiffness, and the triangular models can be used for the cancellous bone for strength. However, none of the models can be used to replace the compact bone because it requires much higher stiffness and strength. In the near future, compact bone replacement must be further studied. In addition, previously mentioned models should be developed further.

• Journal of Korean Neurosurgical Society
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• v.62 no.2
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• pp.144-152
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• 2019

Treatment of chronic subdural hematoma (CSDH) is relatively straightforward, however, there is still some debate regarding the best strategy for treatment. The most practical recommendations of up to date were identified by a review of literature. The author reviewed the literature on CSDH management from the past to now to identify the best methods. Till 1970s, craniotomy was the most commonly used method. Burr hole (BH) became the most preferred method from 1980s. In 1977, twist drill (TD) craniostomy was introduced. Closed system drainage after a BH or a TD became the most frequently used surgical method. Although nonsurgical treatment is often successful, trephination has more advantages, such as rapid resolution of the symptoms and short period of hospitalization. Nonsurgical treatment is possible in asymptomatic patients with a small CSDH. For the symptomatic patients with CSDH, trephination is the treatment of choice, either by BH or TD. In gray zone between surgery and medical treatment, shared decision making can be an ideal approach. For the recurrent CSDHs, repeated trephination is still effective for patients with a low risk of recurrence. If the risk of recurrence is high, additional management would be helpful. For the refractory CSDHs, it is necessary to obliterate the subdural space.

• Archives of Craniofacial Surgery
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• v.22 no.6
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• pp.324-328
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• 2021

Lip defects often occur following wide excision as a surgical treatment for squamous cell carcinoma of the oral cavity. Defects larger than one-half of the lip cannot be closed primarily and require flap surgery. Reconstruction of the oral sphincter function can be achieved by means of a local flap using the like tissue, rather than with a free flap utilizing different tissues. A defect of the lower lip requires reconstruction using different techniques, depending on its size and location. Herein, we present the case of a patient exhibiting a lip defect spanning more than two-thirds of the lower lip, after a wide resection due to squamous cell carcinoma. The defect was reconstructed using an Abbe flap and a staircase flap. Revision was performed after 16 days. The patient's oral competencies were fully restored 3 months postoperatively, and the esthetic results were ideal. Based on our experience, a combination of the Abbe and staircase flaps can produce excellent functional and esthetic outcomes in the reconstruction of a lower lip with a large defect. It can serve as a reliable reconstruction option for defects spanning more than two-thirds of the lower lip, not including the oral commissures.

• Journal of Trauma and Injury
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• v.37 no.2
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• pp.151-157
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• 2024

Electrical burn injuries can cause more damage than clinical evaluations initially suggest. The energy waves penetrate from the surface to the deepest layers of tissue, causing extensive harm at every level. The neck is a critical area, both functionally and aesthetically. We present a case involving a young male patient with a severe fourth-degree electrical burn on the neck, who underwent a single-stage debridement and reconstructive surgery. The pectoralis major myocutaneous flap is a versatile option for various head and neck reconstructions. However, if the donor site cannot be closed primarily and requires split-thickness skin grafting, it can result in unsightly scars and deformities. For large flap paddles, it is ideal to reconstruct the secondary defect with locoregional flaps. In this case, we successfully reconstructed the donor site's secondary defect using a contralateral internal mammary artery perforator flap, without resorting to any skin grafts. The early postoperative results demonstrated satisfactory cosmesis, patient satisfaction, and functional outcomes.

• Archives of Plastic Surgery
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• v.51 no.1
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• pp.102-109
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• 2024

Background Skin defects in the hands are common injuries, and autologous skin grafting is the ideal treatment. However, complications can occur at the donor and recipient sites. This study compares the "Swing-door" technique with conventional skin grafting. Methods From August 2019 to February 2023, 19 patients with skin defects of hand underwent the "Swing-door" split-thickness skin graft (STSG) technique. The thin epithelial layer was elevated with proximal part attached. Skin graft was harvested beneath. Donor site was then closed with epithelial flap like a "Swing-door". The outcomes were evaluated in terms of healing time, scar formation, and pain at the donor and recipient sites. The data were compared with the conventional STSG. Results The "Swing-door" group had lower graft take percentages, but complications did not significantly differ between the two groups. The "Swing-door" technique resulted in better cosmetic outcomes, as evidenced by lower Vancouver Scar Scale scores, faster donor site epithelialization, and reduced pain and discomfort during the early postoperative period, as measured by Visual Analog Scale. Conclusion The "Swing-door" STSG is a useful alternative for treating hand skin defects.

• Clean Technology
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• v.26 no.3
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• pp.161-167
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• 2020

For the design of the prevention and mitigation measures in process industries involving flammable substances, reliable safety data are required. An important property used to estimate the risk of fire and explosion for a flammable liquid is the flash point. Flammability is an important factor to consider when developing safe methods for storing and handling solids and liquids. In this study, the flash point data were measured for the binary systems {2-butanol + 2,2,4-trimethylpentane}, {2-butanol + methylcyclohexane} and {2-butanol + toluene} at 101.3 kPa. Experiments were performed according to the standard test method (ASTM D 3278) using a Stanhope-Seta closed cup flash point tester. A minimum flash point behavior was observed in the binary systems as in the many cases for the hydrocarbon and alcohol mixture that were observed. The measured flash points were compared with the predicted values calculated via the following activity coefficient (GE) models: Wilson, Non-Random Two-Liquid (NRTL), and UNIversal QUAsiChemical (UNIQUAC) models. The predicted data were only adequate for the data determined by the closed-cup test method and may not be appropriate for the data obtained from the open-cup test method because of its deviation from the vapor liquid equilibrium. The predicted results of this work can be used to design safe petrochemical processes, such as the identification of safe storage conditions for non-ideal solutions containing flammable components.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.4
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• pp.79-86
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• 2016

Physical layer security is cryptography technique to protect information by using physical nature of signals. Currently, many works on physical layer security have been actively researching while those researching models still have some problems to be solved. Eavesdropper does not share its channel state information with legitimate users to hide its presence. And when node transmits signal, hardware impairments are occurred, whereas many current researches assume that node model is ideal node and does not consider hardware impairments. The main features and contributions of this paper to solve these problems are as follows. First, our proposed system model deploys torch node around legitimate user to obtain channel state information of eavesdropper and considers hardware impairments by using channel state information of torch node. Second, we derive closed-form expression of intercept probability for the proposed system model. The results of the performance evaluation through various simulations to find out the effects on proposed system model in physical layer security show that imperfect channel state information does not effect on intercept probability while imperfect node model effects on intercept probability, Ergodic secrecy capacity and secrecy capacity.

• Korean Journal of Optics and Photonics
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• v.32 no.1
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• pp.1-8
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• 2021

We have studied a tiled-aperture coherent-beam-combining system based on constructive interference, as a way to overcome the power limitation of a single laser. A 1-watt-level, 3-channel coherent fiber laser and a 3-channel fiber array of triangular tiling with tip-tilt function were developed. A monitoring system, phase controller, and 3-channel phase modulator formed a closed-loop control system, and the SPGD algorithm was applied. Eventually, phase-locking with a rate of 5-67 kHz and peak-intensity efficiency comparable to the ideal case of 53.3% was successfully realized. We were able to develop the essential elements for a tiled-aperture coherent-beam-combining system that had the potential for highest output power without any beam-combining components, and a multichannel coherent-beam-combining system with higher output power and high speed is anticipated in the future.

• Clinical and Experimental Reproductive Medicine
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• v.2 no.1
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• pp.19-38
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• 1975

A total of 185 vasovasostomies were carried out for 11 years. Various factors which are of importance in fluencing the successful vasovasostomies are analysed and presented as follows: In recent years, demand of reanastomosis of the vas deferens increased considerably. An average age of the subjects is 39, and that of their wives, 33 in this series. An average interval between vasectomy and vasovasostomy is 4 years. An average number of living chidren is 2.6 at the time of vasectomy. and 2.1 at the time of time of vasovasostomy. Merchant and public official are the most commonly encounterd occupation in the present series. Coital frequencies are 2.2/week after vasovasostomy. The most common reasons for requesting the vasovasostomy are remarriage and deaths of children, especially son. Success rate is considerably higher among younger group than that of the older. Success rate is somewhat higher among groups of shorter interval between the operations (vasectomy and vasovasostomy) than that of longer interval group. Success rate is higher among bilateral vasovasostomy group than that of any others. Success rate is higher in solid splint group and no splint group than hollow splint group. The closed dressing technique of the end of splint on the scrotum is found to be reasonably effective in preventing infection. Ordinary end-to-end anastomosis and folded side-to-side anastomosis techniques are proved to be the most ideal form of modified operation for the successful vasovasostomies. The most common causes of failure are infection, injuries of blood supply, avascular necrosis due to extensive mobilization, inadequate approximation of both vasal end, hematoma, changes of epididymal environment, and early ambulation in this series. Overall success rate of the author's series is found the 81 per cent, and impregnation rate is 35 per cent. Overall results reported by other workers are that success rate regarding appearance of sperm in the semen after operation is 64 per cent, and that of impregnation after vasovasostomy is 33 per cent. The results of semen assessment performed on same cases prior to vasectomy and following vasovasostomy showed that post-vasovasostomy sperm count scarcely reached three-quaters of pre-vasectomy count.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2008.03a
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• pp.164-164
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• 2008

The beach-chair traction position is designed to allow the use of traction while allowing the surgeon to orient the shoulder in an upright position and convert to an open procedure, if necessary. The patient is placed in the beach-chair position under general anesthesia. A three-point shoulder holder (Arthrex, Naples, Florida) is attached to the rail of the operating table on the same side as the surgeon, whereas it is placed on the side opposite the surgeon in the lateral decubitus position. A shoulder traction and rotation sleeve (Arthrex) are affixed to the arm following the manufacturer's instructions. Positioning the thumb toward the closed side of the sleeve ensures a field for the anterior portion of the rotator cuff and prevents the tendency of the suspension apparatus to place the arm in internal rotation. The arm is maintained in 30 to 40 degree abduction and 30 to 40 degree flexion by controlling the length and height of the bar and the location of the universal clamp. The universal clamp allows multiple planes of adjustment to control abduction and forward movement of the arm. The sleeve is attached to the longitudinal traction cable using a sterile hook, and a lateral strap is secured around the proximal portion of the sleeve to the overhead traction cable to ensure a field for glenohumeral reconstruction. The use of a lateral strap permits ideal shoulder positioning for improved access to the anterior and inferior glenohumeral joint. The lateral strap can be released or removed to widen the subacromial space during subacromial decompression or rotator cuff repair. A 10-lb weight is attached to the longitudinal traction cable for an average-sized person.