• Journal of Welding and Joining
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• v.21 no.2
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• pp.57-63
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• 2003

Since new types of vehicles or structures made from thin aluminum alloy are under rapid development and some products are already on the market, welding of aluminium sheet is increasing. MIG(Metal Inert Gas), MIG-Pulse, TIG(Tungsten Inert Gas) welding are the typical Ai welding. MIG welding has the advantage of high speed, but it is difficult to apply to the thin plate, because of bum-through by the high heat input and spatter. MIG-Pulse welding can weld without spatter and burn-through, but when the gap exists at the welding joint, there is quite a possibility of bum-through. TIG welding is difficult to weld at a high speed. AC Pulse welding alternates between DCEP(Direct Current Electrode Positive) and DCEN(Direct Current Electrode Negative). DCEN is higher wire melting rate than DCEP, while lower temperature of droplet than DCEP. In AC Pulse welding, far fixed welding current, wire melting rate increases as the EN ratio increases. For fixed wire feed rate, welding current decreases as the EN ratio increases. Because of these features, the temperature of droplet, the depth of penetration, the width of bead decrease and the reinforcement height increases as EN ratio increases, and these are able to weld at a high speed, lower heat input. It is the purpose of this study that design of AC pulse current waveform for MIG welding of Al sheet and estimation of output characteristic.

• Pediatric Infection and Vaccine
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• v.12 no.2
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• pp.157-165
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• 2005

Purpose : Children occupy a large proportion of burn victims. So we want to aid to pediatric burn care through the understanding of the bacterial distribution in burn wounds and antibiotic susceptibility against isolated microorganisms from burn wounds. Methods : We analysed the medical records of 213 pediatric burn patients(0~15 years), 406 samples that grew bacteria in burn wound sites. Results : Of the total 213 patients, male were 59.6% and female were 40.4%. Scalding burn was the most common(78.4%), flame burn was the second(16.4%). Pathogens were isolated in 406 samples. The most common was Pseudomonas aeruginosa(58.1%). Next were Enterococcus species, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus species, Acinetobacter species. P. aeruginosa was resistant to trimethoprim-sulfamethoxazole in 100%, cephalothin in 98.1%, ampicillin-sulbactam in 96.2%, ampicillin in 95.3%, ceftriaxone in 95.2%, tobramycin in 93.7%, cefoperazone in 68.9%, ceftazidime in 67.7%. Enterococcus species were resistant to tetracycline in 63.9%, streptomycin in 45.5%, gentamicin in 36.1%, penicillin G in 13.7%. S. aureus was resistant to gentamicin in 89.7%, tetracycline in 86.2%, ciprofloxacin in 86.2%, penicillin G in 84.3%, oxacillin in 78.4%, erythromycin in 76.5%. Acinetobacter species were resistant to ampicillin-sulbactam in 100%, gentamicin in 85.7%, ampicillin in 83.3%, piperacillin in 61.5%. Conclusion : P. aeruginosa was highly resistant to drugs like cefoperazone in 68.9%, ceftazidime 67.7%. S. aureus was highly resistant to penicillin G in 84.3%, oxacillin in 25.9 %, but none to vancomycin in 0%, teicoplanin in 2.2%. According to the study, Acinetobacter species turned out to be multi-resistant strains, so careful attention must be paid to the choice of antibiotics.

• BMB Reports
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• v.42 no.12
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• pp.800-805
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• 2009

This study investigated the effect of subconjunctival injections of bevacizumab, an anti-VEGF antibody, on processes involved in corneal wound healing after alkali burn injury. Mice were divided into three groups: Group 1 was the saline-treated control, group 2 received subconjunctival injection of bevacizumab 1hr after injury and group 3 received bevacizumab 1 hr and 4 days after injury. Cornea neovascularization and opacity were observed using a slit lamp microscope. Corneal repair was assessed through histological analysis and immunostaining for CD31, $\alpha$-SMA, collagen I, and TGF-$\beta$2 7 days post-injury. In group 3, injection of bevacizumab significantly lowered neovascularization and improved corneal transparency. Immunostaining analysis demonstrated a reduction in CD31, $\alpha$-SMA and TGF-$\beta$2 levels in stroma compared to group 1. These results indicate that bevacizumab may be useful in reducing neovascularization and improving corneal transparency following corneal alkali burn injury by accelerating regeneration of the basement membrane.

• Journal of The Korean Society of Clinical Toxicology
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• v.8 no.1
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• pp.43-45
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• 2010

A 22-year-old woman was referred to our emergency department for the treatment of a chemical injury on her arm. She had accidentally spilled 99% trifluoroacetic anhydride (TFAA) over her left forearm during an organic chemistry experiment. She visited a primary care unit, and then she was referred to our hospital for inactivation of the released fluoride ions. Her skin lesions were different from those caused by hydrofluoric acid (HF) injury. The injured area showed painful whitish maculae and patchy areas with accentuated rim. No vesiculation and bulla formation was detected. We intradermally injected a 5% solution of calcium through a 24-gauge needle into the burned skin. After the injection, she complained of more severe pain. Although TFAA contains fluorine, it does not release free fluoride ions on contact with the skin, unlike HF. In fact, application of calcium gluconate for TFAA burns is not recommended. Rather, it should be avoided since it increases pain and local abscess formation.

• Journal of Astronomy and Space Sciences
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• v.32 no.3
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• pp.257-268
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• 2015

Characteristics of delta-V requirements for deploying an impactor from a mother-ship at different orbital altitudes are analyzed in order to prepare for a future lunar CubeSat impactor mission. A mother-ship is assumed to be orbiting the moon with a circular orbit at a 90 deg inclination and having 50, 100, 150, 200 km altitudes. Critical design parameters that are directly related to the success of the impactor mission are also analyzed including deploy directions, CubeSat flight time, impact velocity, and associated impact angles. Based on derived delta-V requirements, required thruster burn time and fuel mass are analyzed by adapting four different miniaturized commercial onboard thrusters currently developed for CubeSat applications. As a result, CubeSat impact trajectories as well as thruster burn characteristics deployed at different orbital altitudes are found to satisfy the mission objectives. It is concluded that thrust burn time should considered as the more critical design parameter than the required fuel mass when deducing the onboard propulsion system requirements. Results provided through this work will be helpful in further detailed system definition and design activities for future lunar missions with a CubeSat-based payload.

• Proceedings of the Korean Society of Tobacco Science Conference
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• 2000.05a
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• pp.12-21
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• 2000

The smoke from a burning cigarette is classified as mainstream, which is the smoke inhaled by the smoker during a puff, and sidestream, which is defined by ISO 10185 as all smoke which leaves a cigarette during the smoking process other than from the butt end. Most of the sidestream smoke is generated during static burn, that is, in between puffs. The amount of sidestream smoke generated by a cigarette depends on the cigarette construction, tobacco blend, and properties of the cigarette paper, The main paper properties affecting sidestream smoke generation are: porosity, basis weight, type and amount of filler, type and amount of burn additive.Sidestream smoke is composed of a visible phase (small liquid droplets) and an invisible phase (gaseous molecules). This paper focuses on the visible portion of the sidestream smoke. Optical methods, which are based on the relationship between light scattering and density of the rising plume of smoke, have been used successfully by the industry. However, the present trend is to use gravimetric methods where the particulate matter is captured on a Cambridge(R) filter pad and weighed. The gaseous portion of the sidestream smoke, which does not contribute to the visible sidestream smoke, passes through the Cambridge filter pad.Sidestream smoke reduction is achieved by modifying certain mass transport processes occurring in a smoldering cigarette. There are four main pathways for reducing sidestream smoke: A) less tobacco burned, B) slower rate of tobacco combustion, C) more efficient trapping of smoke by the cigarette paper, and D) more complete combustion of tobacco. This paper discusses how the physical properties of paper and cigarette construction affect sidestream smoke reduction via the above four mechanisms.

• Journal of the Korean Burn Society
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• v.24 no.2
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• pp.50-52
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• 2021

Iatrogenic electrical burns that occur from the use of a defibrillator, a paddle-type cardiac shock device, have been reported in various forms. Electrical burns are usually conducted directly through the skin and are more damaging than scald burns or contact burns. A transcutaneous cardiac pacing device is a patch-type cardiac shock device that automatically delivers a shock when an abnormal heart rhythm is detected. We introduce a unique case of iatrogenic electrical burns caused by the transcutaneous pacing patch of a cardiac shock device. Electrical energy was converted into a spark due to foreign bodies deposited around the patch, resulting in damage to the peripheral area of the skin.

• Archives of Plastic Surgery
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• v.38 no.4
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• pp.451-457
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• 2011

Purpose: As a central feature of the face, the nose has considerable significance in appearance and expression. Reconstruction of full thickness defects of the nasal ala has always been a challenge because of the 3-dimensional structure. For reconstruction of post burn defects of ala, skin graft, local or pedicled flap and composite graft are optionally available. We have reconstructed the ala defects using adiposocutaneous graft and observed the outcome. Methods: From March 2003 to December 2010, 19 cases in 11 patients with scar contracture and defect on ala portion were performed operation using adiposocutaneous graft. As a donor site, we used the inguinal crease and posterior auricular area and the donor site was primarily closed. We made incision through the superior rim of ala and released fully. A graft is applied to recipient site with larger size than recipient volume. Results: The mean age of the patient was 38.6 years (16~51), males are seven patients and females are four patients. The operation was performed bilaterally in 5 patients and unilaterally in 6 patients. Composite grafts were harvested from inguinal area in 13 cases and posterior auricular area in 6 cases. In one case, we did 4 times of operation to get enough volume. All the grafts were well taken. The mean size of the graft was 3.63 $cm^2$. Conclusion: For reconstruction of post burn defects of ala, it's not easy to use local flap or pedicled flap because of hardness and fibrosis of surrounding tissue. So, we choose adiposocutaneous graft for ala deformity reconstruction, got satisfactory outcome in color matching and texture.

• Journal of the Korean Society of Safety
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• v.37 no.6
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• pp.136-147
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• 2022

The purpose of this study is to analyze four cases of firefighter burns in various fire scenes and to find prevention measures to decrease firefighter injuries. Among the analysis reports prepared by the National Fire Research Institute of Korea from 2016 to 2020, four burn-related accidents are summarized and the main causes are conveyed. The four accidents include second-degree burns from using extinguishers during containment of fires; nine firefighters burned due to re-ignition in the LPG car repair shop; two firefighters injured with third-degree burns from using fire extinguishers during life-saving events in residential housing; and injuries from the radiant heat of the tank BLEVE near the factory fire. These cases are comprehensively investigated in their respective scenes and analyzed based on the fire site investigation reports from the fire department and related theoretical explanations of risk for each accident scene. In the third case study, some experimental research is conducted to evaluate the risk involved with the use of safety gloves. This is evaluated by reviewing Fire Tactics and Standard Operational Procedures (SOP) to determine improvements and recommendations for an efficient firefighting response. Results show that the main causes of burn accidents are the insufficient use of personal protective equipment (PPE), such as safety gloves, and the failure to follow firefighting tactics or SOPs. Through the accident investigation and assessment, it is concluded that to reduce the frequency of burn accidents, the performance of firefighting equipment, SOPs, protection tactics, and safety policy systems require improvement.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.148-154
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• 2022

As the 4th industrial age approaches, the demand for semiconductors is increasing enough to be used in all electronic devices. At the same time, semiconductor technology is also developing day by day, leading to ultraprecision and low power consumption. Semiconductors that keep getting smaller generate heat because the energy density increases, and the generated heat changes the shape of the semiconductor package, so it is important to manage. The temperature change is not only self-heating of the semiconductor package, but also heat generated by external damage. If the package is deformed, it is necessary to manage it because functional problems and performance degradation such as damage occur. The package burn in test in the post-process of semiconductor production is a process that tests the durability and function of the package in a high-temperature environment, and heat dissipation performance can be evaluated. In this paper, we intend to review a new material formulation that can improve the performance of the adapter, which is one of the parts of the test socket used in the burn-in test. It was confirmed what characteristics the basic base showed when polyamide, a high-molecular material, and alumina, which had high thermal conductivity, were mixed for each magnification. In this study, functional evaluation was also carried out by injecting an adapter, a part of the test socket, at the same time as the specimen was manufactured. Verification of stiffness such as tensile strength and flexural strength by mixing ratio, performance evaluation such as thermal conductivity, and manufacturing of a dummy device also confirmed warpage. As a result, it was confirmed that the thermal stability was excellent. Through this study, it is thought that it can be used as basic data for the development of materials for burn-in sockets in the future.