• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.1-6
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• 2006

Abstract - Global decline in wildlife mammals has been accelerated during past decades. Especially the conservation the wild life mammals in polar areas, is urgent. In an effort to understand the reproduction of the seals dwelling in the polar area, spermatogenesis in the seals was reviewed. Seals breed seasonally and in most of the seal species, delayed implantation is frequently observed. To date, histological and endocrinological evaluation revealed highly cyclic nature in supermatogenesis and steroidogenesis in testis. Seasonal changes in blood testosterone level together with melatonin is closely related with changes in light cycle between summer and winter. In adult testis at breeding seasons, spermatogenesis is manifested by consecutive 18 stages of germ cell development. Three kinds of Leydig cells different in steroidogenic activity as well as cellular morphology appear during the testis development. During non-breeding season, spermatogenic arrest and Leydig cell hypoplasia are frequently found. Interestingly, blood circulation through the anastomoses of pelvic veins cooled the testes and thus guarantees spermatogenesis within the body trunk. Endocrine disruptors and heavy metals have been found in the body tissues of several seals species and alter steroidogenesis in seals, suggesting environmental pollutants together with decrease in habitats are potentially threatening the reproductive success in seal species.

• International Journal of Fluid Machinery and Systems
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• v.4 no.1
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• pp.67-75
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• 2011

Recent results are presented concerning the development of magnetofluidic leakage-free rotating seals for vacuum and high pressure gases, evidencing significant advantages compared to mechanical seals. The micro-pilot scale production of various types of magnetizable sealing fluids is shortly reviewed, in particular the main steps of the chemical synthesis of magnetic nanofluids and magnetic composite fluids with light hydrocarbon, mineral oil and synthetic oil carrier liquids. Design concepts and some constructive details of the magnetofluidic seals are discussed in order to obtain high sealing capacity. Different types of magnetofluidic sealing systems and applications are reviewed. Testing procedures and equipment are presented, as well as the sealing capabilities of different types of magnetizable fluids.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.8
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• pp.661-668
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• 2016

Oil deflector prevents oil leakage that occurs in thermoelectric power plant at operating lubricant facilities. Vibration of rotating rotor-induced wear of aluminum tooth in existing oil deflector leads to oil leakage as well as life shortening of the tooth. In this study, an advanced oil deflector was developed for shock absorption and prevention of wear by decreasing clearance (from 0.5 mm to 0.2 mm) between rotor and tooth to minimize oil leakage, and by replacing 2 aluminum teeth in outmost of the oil deflector with hi-performance seal made of engineering plastic. The CFD results were compared between advanced vs. existing oil deflector to determine the amount of oil loss. Structural safety was verified through impact analyses according to the three kinds of engineering plastics, considering cost efficiency, and optimal material of hi-performance seal was chosen.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.1 s.119
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• pp.69-77
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• 2007

Carton and corrugated paperboard have excellent convertibility characteristics that could be easily slitted, folded, and inserted to become a certain shape of box or case. This excellent processing characteristics of carton and corrugated paperboard as well as their recyclability will continue to make them possess high portion in packaging markets. However, staple, tape, or adhesive have been used to seal a paperboard packaging box or case. Staples among them have been frequently used in many cases because of their convenience. Staples could enter the inside the box and give wounds to the goods in the box or case. Furthermore additional handling and waste treatment costs in the making and recycling processes would be necessary when staple is used to seal box or case. This study has been carried out to develop non-staple paperboard packaging box & case designs that can be used to make non-staple boxes & cases. It is believed that the non-staple folding paperboard boxes & cases could be more environmental-friendly, beautiful, and economic than staple boxes & cases.

• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.220-239
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• 2019

According to the National Currency (國幣) article in GyeongGukDaeJeon (經國大典), the ChoSonT'ongPaeJiIn (朝鮮通幣之印) was a seal that was imprinted on both ends of a piece of hemp fabric (布). It was used for the circulation of hemp fabric as a fabric currency (布幣). The issued fabric currency was used as a currency for trade or as pecuniary means to have one's crime exempted or replace one's labor duty. The ChoSonT'ongPaeJiIn would be imprinted on a piece of hemp fabric (布) to collect one-twentieth of tax. The ChoSonT'ongPaeJiIn (朝鮮通幣之印) was one of the historical currencies and seal materials used during the early Chosun dynasty. Its imprint was a means of collecting taxes; hence, it was one of the taxation research materials. Despite its value, however, there has been no active research undertaken on it. Thus, the investigator conducted comprehensive research on it based on related content found in JeonRokTongGo (典錄通考), Dae'JeonHu-Sok'Rok (大典後續錄), JeongHeonSwaeRok (貞軒?錄) and other geography books (地理志) as well as the materials mentioned by researchers in previous studies. The investigator demonstrated that the ChoSonT'ongPaeJiIn was established based on the concept of circulating Choson fabric notes (朝鮮布貨) with a seal on ChongOseungp'o (正五升布) in entreaty documents submitted in 1401 and that the fabric currency (布幣) with the imprint of the ChoSonT'ongPaeJiIn was used as a currency for trade, pecuniary or taxation means of having one's crime exempted, or replacing one's labor, and as a tool of revenue from ships. The use of ChoSonT'ongPaeJiIn continued even after a ban on fabric currencies (布幣) in March 1516 due to a policy on the "use of Joehwa (paper notes)" in 1515. It was still used as an official seal on local official documents in 1598. During the reign of King Yeongjo (英祖), it was used to make a military service (軍布) hemp fabric. Some records of 1779 indicate that it was used as a means of taxation for international trade. It is estimated that approximately 330 ChoSonT'ongPaeJiIn were in circulation based on records in JeongHeonSwaeRok (貞軒?錄). Although there was the imprint of ChoSonT'ongPaeJiIn in An Inquiry on Choson Currency (朝鮮貨幣考) published in 1940, there had been no fabric currencies (布幣) with its imprint on them or genuine cases of the seal. It was recently found among the artifacts of Wongaksa Temple. The seal imprint was also found on historical manuscripts produced at the Jikjisa Temple in 1775. The investigator compared the seal imprints found on the historical manuscripts of the Jikjisa Temple, attached to TapJwaJongJeonGji (塔左從政志), and published in An Inquiry on Choson Currency with the ChoSonT'ongPaeJiIn housed at the Wongaksa Temple. It was found that these seal imprints were the same shape as the one at Wongaksa Temple. In addition, their overall form was the same as the one depicted in Daerokji (大麓誌) and LiJaeNanGo (?齋亂藁). These findings demonstrate that the ChoSonT'ongPaeJiIn at Wongaksa Temple was a seal made in the 15th century and is, therefore, an important artifact in the study of Choson's currency history, taxation, and seals. There is a need for future research examining its various aspects.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.36 no.2
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• pp.165-173
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• 2020

The purpose of this research is to evaluate the health performance of existing buildings which completed green remodeling using the WELL Building Standard developed by Delos in the USA. The features and the level of improvement in health were examined and the results were as follows. As a result of comprehensive evaluation of the health performance of the target building, the health performance after green remodeling improvement was improved by 17.3% compared to before green remodeling. As a result of applying the alternatives for improving health performance, improvements were 22.9% by Alternative 1, 28.8% by Alternative 2, and 28.7% by Alternative 3. If the improvement ratio with respect to the construction cost were compared, Alternative 1 was the best followed by Alternative 2. Finally, the cost effectiveness of improving health performance against construction cost were best in the order of self-closing door installation, airtight seal, and pest inspections.

• Journal of the Korean Ceramic Society
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• v.45 no.12
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• pp.802-806
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• 2008

A proper sealant for low temperature SOFCs should show zero or low leak rates to avoid direct mixing of the fuel and oxidant gases or leakage of fuel gas during the operation of SOFCs. Furthermore, it should be chemically and/or mechanically stable in both oxidizing and reducing environments and chemically compatible with other fuel cell components. In the present work, we developed a novel compressed seal gasket of glass-based composite reinforced with ceramic particulate particles, which can efficiently control the viscous flow of glass matrix as well as the crystallization of glass phase. This novel sealing gasket showed excellent gas tightness under very low compressive load which would be suitable for the operation of SOFCs in the temperature range $600{\sim}650^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1110-1116
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• 2003

The effects of packaging methods on the storage quality of minimally processed (prepeeled) onions were investigated to determine the optimal packing design. Various packaging treatments used for modifying headspace atmospheres included two passive MAP using LDPE and PP films, two active MAP using a gas mixture of 20% $O_2/10%\;CO_2/balance\;N_2$ and an ethylene scavenging sachet, and moderate vacuum packaging (MVP). The quality attributes of onion samples were evaluated periodically in terms of flesh weight loss, color of cut surface, decay ratio, microbial counts, and sensory properties during storage at $10^{\circ}C$ for 28 days. Packaging methods did not significantly influence surface color, weight loss, and microbiological populations of mesophiles, psychrotrophs, and lactic acid bacteria. They did, however, affect sensory characteristics as well as decay occurrence. Results indicated that seal-packaging with a gas-permeable plastic film under a mild vacuum condition could retain better onion quality in terms of microbial decay and visual sensory aspects as compared with the other packages.

• Tuberculosis and Respiratory Diseases
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• v.81 no.2
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• pp.106-115
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• 2018

Chest tube insertion is a common procedure usually done for the purpose of draining accumulated air or fluid in the pleural cavity. Small-bore chest tubes (${\leq}14F$) are generally recommended as the first-line therapy for spontaneous pneumothorax in non-ventilated patients and pleural effusions in general, with the possible exception of hemothoraces and malignant effusions (for which an immediate pleurodesis is planned). Large-bore chest drains may be useful for very large air leaks, as well as post-ineffective trial with small-bore drains. Chest tube insertion should be guided by imaging, either bedside ultrasonography or, less commonly, computed tomography. The so-called trocar technique must be avoided. Instead, blunt dissection (for tubes >24F) or the Seldinger technique should be used. All chest tubes are connected to a drainage system device: flutter valve, underwater seal, electronic systems or, for indwelling pleural catheters (IPC), vacuum bottles. The classic, three-bottle drainage system requires either (external) wall suction or gravity ("water seal") drainage (the former not being routinely recommended unless the latter is not effective). The optimal timing for tube removal is still a matter of controversy; however, the use of digital drainage systems facilitates informed and prudent decision-making in that area. A drain-clamping test before tube withdrawal is generally not advocated. Pain, drain blockage and accidental dislodgment are common complications of small-bore drains; the most dreaded complications include organ injury, hemothorax, infections, and re-expansion pulmonary edema. IPC represent a first-line palliative therapy of malignant pleural effusions in many centers. The optimal frequency of drainage, for IPC, has not been formally agreed upon or otherwise officially established.

• Tribology and Lubricants
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• v.35 no.5
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• pp.267-273
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• 2019

Wheel bearings are important automotive parts that bear the vehicle weight and translate rotation motion; in addition, their seals are components that prevent grease leakage and foreign material from entering from the outside of the bearings. Recently, as the need for electric vehicles and eco-friendly vehicles has been emerging, the reduction in fuel consumption and $CO_2$ emissions are becoming the most important issues for automobile manufacturers. In the case of wheel bearings, seals are a key part of drag torque. In this study, we investigate the prediction of the drag torque taking into consideration the hyperelastic and viscoelastic material properties of automotive wheel bearing seals. Numerical analysis based on the finite element method is conducted for the deformation analyses of the seals. To improve the reliability of the rubber seal analysis, three types of rubber material properties are considered, and analysis is conducted using the hyperelastic material properties. Viscoelastic material property tests are also conducted. Deformation analysis considering the hyperelastic and viscoelastic material properties is performed, and the effects of the viscoelastic material properties are compared with the results obtained by the consideration of the hyperelastic material properties. As a result of these analyses, the drag torque is 0.29 Nm when the hyperelastic characteristics are taken into account, and the drag torque is 0.27 Nm when both the hyperelastic and viscoelastic characteristics are taken into account. Therefore, it is determined that the analysis considering both hyperelastic and viscoelastic characteristics must be performed because of its reliability in predicting the drag torque of the rubber seals.