• Korean Journal of Metals and Materials
• /
• v.46 no.10
• /
• pp.652-661
• /
• 2008

Reduction of NOx in emission gas, improvement of engine efficiency, and extension of warranty period has made demands for developing materials more corrosively resistant to the inner-muffler environments or predicting the lifetime of materials used in muffler more precisely. The corrosion inside muffler has been explained with condensate corrosion mainly though thermal oxidation experiences prior to condensate corrosion. Hence, the aim of this study is to describe how the thermal oxidation affects the corrosion of stainless steel exposed to the inner-muffler environments. Auger electron spectroscopy and electrochemical tests were employed to analyze oxide scale and to evaluate corrosion resistance, respectively. Thermal oxidation has different role of condensate corrosion depending on the temperature: inhibiting condensate corrosion below $380^{\circ}C$ and enhancing condensate corrosion above $380^{\circ}C$. The low temperature oxidation causes to form compact oxide layer functioning a barrier for penetrating condensate into a matrix. Although though thermal oxidation caused chromium-depleted layer between oxide layer and matrix, the enhancement of the condensate corrosion in high temperature oxidation resulted from corrosion-induced crevice formed by oxide scale rather than corrosion in chromium-depleted layer. It was proved by aids of anodic polarization tests and measurements of pitting corrosion potentials. By the study, the role of high temperature oxidation layer affecting the condensate corrosion of stainless steels used as muffler materials was well understood.

• Archives of Craniofacial Surgery
• /
• v.22 no.3
• /
• pp.168-172
• /
• 2021

Posttraumatic pseudoaneurysm of the face is caused by blunt, penetrating, or surgical trauma. Although its incidence is low, pseudoaneurysm rupture can cause a life-threatening, massive hemorrhage. A 48-year-old man visited our emergency center due to a fall-down accident. Three-dimensional computed tomography (CT) showed a comminuted zygomaticomaxillary complex fracture of the left face. After open reduction and internal fixation, the surgical wound healed without any complications. However, the patient was readmitted 10 days after surgery due to pus-like discharge from the wound. Contrast-enhanced CT to find the abscess unexpectedly revealed a pseudoaneurysm in the left retromaxillary area. Massive oral bleeding occurred on the night of re-hospitalization and emergency surgery was done. The bleeding site was identified as a pseudo-aneurysmal rupture of the posterior superior alveolar artery in the retromaxillary area. Hemostasis was achieved by packing Vaseline gauze in the maxillary sinus using an endoscope. Delayed rupture and massive bleeding of posttraumatic retromaxillary pseudoaneurysm after a zygomaticomaxillary fracture is a low-probability, but high-impact event. Therefore, additional contrast-enhanced CT should be considered to evaluate the possibility of a posttraumatic pseudoaneurysm in cases of severe comminuted zygomaticomaxillary fracture.

• Archives of Plastic Surgery
• /
• v.48 no.2
• /
• pp.231-236
• /
• 2021

Mucormycosis is an invasive, rapidly progressive, life-threatening fungal infection, with a propensity for diabetic, immunosuppressed, and trauma patients. The classic rhinocerebral variation is most common in diabetic patients. While the cutaneous form is usually caused by direct inoculation in immunocompetent patients. Cutaneous mucormycosis manifests in soft tissue and risks involvement of underlying structures. Tibial osteomyelitis can also occur secondary to cutaneous mucormycosis but is rare. Limb salvage is typically successful after lower extremity cutaneous mucormycosis even when the bone is involved. Herein, we report two cases of lower extremity cutaneous mucormycosis in diabetic patients that presented as acute worsening of chronic pretibial ulcers. Despite aggressive antifungal therapy and surgical debridement, both ultimately required amputation. Such aggressive presentation has not been reported in the absence of major penetrating trauma, recent surgery, or burns.

• East Asian Journal of Business Economics (EAJBE)
• /
• v.9 no.1
• /
• pp.53-61
• /
• 2021

Purpose - This study aims to understand the phenomenon called "regional multinational" in the geographical expansion of multinational enterprises and to find some evidence whether globalization of multinational enterprises tends to have a strong home region bias. Research design, data, and methodology - Through an in-depth case analysis, we analyze the series of strategic behaviors Wal-Mart made in South Korea from its entry in 1998 to its withdrawal in 2006. Then, we discuss the plausible causes of this exit, seeking to provide some evidence on the "regional multinational" phenomenon. Result - This study finds some evidence on the regional-based expansion of multinational enterprises. Our case study shows that Wal-Mart in South Korea focused on global standardization strategy and made an exit from the market as they were faced with increasing localization demands. From the perspective of multinational enterprises' globalization strategy, Wal-Mart's exit from the South Korean market can be considered as a strategic exit. Conclusion - The findings of this study suggest that while national responsiveness and localized adaptation are considered as a panacea for penetrating international markets, in reality most multinational enterprises attempt to add value primarily by capitalizing on similarities across markets and remain as regional multinationals.

• Korean Journal of Head & Neck Oncology
• /
• v.38 no.1
• /
• pp.11-16
• /
• 2022

HHPV (Human Papillomavirus) is a DNA virus that can cause benign lesions, genitourinary cancer, and oropharyngeal cancer by penetrating the mucous membrane and skin. It is widely known to be transmitted mainly through sexual contact. As with many viral infections, vaccines have been developed to prevent infection with HPV. Currently, in many countries, HPV vaccines are mainly used for national immunization for women to prevent diseases that traditionally occur frequently in women, especially cervical cancer. However, since the vaccination rate is relatively low, many countries are struggling with ways to increase the vaccination rate. Meanwhile, the incidence of oropharyngeal cancer caused by HPV in men has been increasing recently. In the United States, the annual number of oropharyngeal cancers in men already exceeds the number of cervical cancers in women, so HPV infection in men has emerged as a major problem. Accordingly, interest in HPV vaccination in men has also increased, and studies on the effectiveness and necessity of vaccination of both women and men compared to women alone are being actively conducted. In this paper, the evidence of HPV vaccination for men will be reviewed through previous studies, and its validity and cost-effectiveness will be analyzed to bolster the clinical usefulness of HPV vaccination for men.

• Advances in nano research
• /
• v.13 no.1
• /
• pp.13-28
• /
• 2022

The pumpability of the grouts is significant issue in concept of the rheological and workability properties during penetrating to voids and cracks. To improve the fluidity features of the grout mixes, the usage of Colloidal Nano Particular Powders (CNPPs) with mineral additives such as fly ash (FA) can contribute. Therefore, the main purpose of this study can be explained as investigating the usage effects of four types of Colloidal Nano Particular Powders (n-TiO₂, n-ZnO, n-Al₂O₃ and n-SiO₂) as nano additives on the rheological, workability and bleeding properties of cement-based grout incorporated with fly as. Test results showed that the usage of FA in the grout samples positively contribute to increase on the fluidity of the grout samples as expected. The dilatant behavior was observed from the results for all mixes. Observing the effect of nano-sized additives in such cement-based grout mixtures with high fluidity has presented remarkable effects in this study.

• Nuclear Engineering and Technology
• /
• v.53 no.12
• /
• pp.4003-4013
• /
• 2021

During the long-term cooling (LTC) phase of a loss-of-coolant accident (LOCA) in a pressurized water reactor (PWR), water is supplied from the containment sump to the reactor coolant system (RCS) by the flooded sump water to the Reactor Vessel (RV) through the broken pipes. As part of the technical efforts for resolving GSI-191 [( Reid and Crytzer, May. 2007) 1, consideration is needed for the consequences of debris penetrating the sump screen and propagating downstream into the RV. Injection of debris (fiberglass) into the RV during the LTC recirculation phase needs special attention to assure that reactor core cooling is maintained. The point of concern is the potential for debris to adversely affect the reactor core flow paths or heat transfer [2]. However, all the experiments for proving the coolability of RV have been done with the assumption of the most of debris would be transferred to the RV and the bottom nozzle of the FAs. The purpose of the tests is to quantify the amount of the debris that would be accumulated at the lower plenum and the debris that passes through the FAs since non-conservatism of other researches assumptions that have been used in the past experimental or analytical programs.

• Journal of the Korean Orthopaedic Association
• /
• v.55 no.5
• /
• pp.431-435
• /
• 2020

Pseudoaneurysm which is usually caused by high energy trauma or penetrating injury results in serious complications if the diagnosis is delayed. The authors experienced a 63-year-old patient who slipped on the stairs with simple contusion and skin laceration. But, he was finally diagnosed with pseudoaneurysm of tibioperoneal trunk of tibial artery on magnetic resonance imaging and 3-dimensional computed tomography angiogram performed in two weeks due to aggravation of the symptoms. To the best of my knowledge, pseudoaneurysm of tibio-peroneal trunk caused by minor blunt trauma has not been reported till now in Korea. So we report this case with a review of the relevant literature.

• Clinics in Shoulder and Elbow
• /
• v.24 no.3
• /
• pp.141-146
• /
• 2021

Background: The purpose of the present study was to determine how long superior screws alone or in combination with posterior placement of metaglene screws protruding and penetrating into the scapular spine in reverse total shoulder arthroplasty affect the strength of the scapular spine in a fresh cadaveric scapular model. Methods: Seven fresh cadaver scapulas were allocated to the control group (short posterior and superior screws) and seven scapulars to the study group (spine base fixation with a four long screws, three with both long superior and long posterior screws). Results: The failure load was lower in the spine fixation group (long screw, 869 N vs. short screw, 1,123 N); however, this difference did not reach statistical significance (p>0.05). All outside-in long superior or superior plus posterior screws failed due to scapular spine base fracture; failures in the short screw group were due to acromion fracture. An additional posterior outside-in screw failed to significantly decrease the failure load of the acromion spine. Conclusions: The present study highlights the significance of preventing a cortical breach or an outside-in configuration when a superior or posterior screw is inserted into the scapular spine base.

• Journal of Conservation Science
• /
• v.38 no.4
• /
• pp.254-264
• /
• 2022

Built in the 6th and 7th centuries during the Baekje period, the Buyeo Royal Tombs consist of seven tombs, including Tomb No. 1, which contains murals. To preserve Tomb No. 1 from damage caused by microorganisms, periodic microbial-distribution investigations are conducted. Following such investigations in August 2016, June 2018, and November 2019, the microbes were classified according to the investigation period, location of collection, and space. This study compares and analyzes the results. The concentration of airborne microorganisms in Tomb No. 1 and the number of microbial genera identified in each space of the tomb decreased as proximity to the main room with murals diminished. During the investigation period, the genera Bacillus, Cladosporium, Penicillium, and Streptomyces were commonly identified on Tomb No. 1. The microorganisms collected from the main room walls were mostly isolated from the east and west walls where the genera Bacillus, Cupriavidus, Paenibacillus, Pseudomonas, and Streptomyces were commonly identified in three or more walls. In particular, the genus Streptomyces is a dangerous strain capable of damaging murals by penetrating into and discoloring the pigments on them. The data generated from this study may be useful for future research on microbial distribution in other domestic mural tombs and those located in North Korea and abroad.