• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.3
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• pp.300-305
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• 2008

Purpose: The purpose of our study was to evaluate the volume of pre- and post operative masseter muscle and bite force in mandibular prognathic patients treated with SSRO with the use of the 3D CT imaging technique and occlusal force meter. Materials and methods: The study group consisted of 12 patients with mandibular prognathism (5 males and 7 females) who underwent mandibular setback surgery (BSSRO) in the Department of Oral and Maxillofacial Surgery, Samsung medical center. Bite force was measured at pre op, post op 3, 6 and 12 months by occlusal force meter(GM10, Nagano Keiki, Japan) The preoperative CT examination of subjects was performed between one month prior to operation and one year after to operation. And muscle volume was measured. Result: As compared to preoperative measurements at 1 year postoperatively the masseter & internal pterygoid muscle volume were diminished (p<0.05) The bite force steadily recovered, so at postoperatively 6 months reached the preoperative level. And at 1 year after operation, the maximum bite force was significantly greater than preoperative levels. No significant correlation was presented between masseter muscle and bite force (p>0.05), internal pterygoid muscle and bite force (p>0.05). Conclusion: In this study, the results showed that volume and bite force of the masticatory muscles decreased significantly immediate after orthognathic surgery for mandibular set-back. However, reduction of maximum bite force disappears within 6 months after surgery.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.1
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• pp.41-46
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• 2020

PCR PET flake's market endeavors difficult situations of its oversupply and decreasing demands in South Korea. Since China banned the import of most recycled plastics, flake producers who mostly export the flakes lost their biggest market. The producers struggled to survive in the competitions with PCR PET flake from EU and 3^rd countries but it was challenging due to substandard quality and increasing cost. Attempts to improve the quality of PCR PET flake have been made but they were only an individual company's efforts. The objective of this study was to understand the market status on PCR PET flake in South Korea and to present suggestions for improving its quality. The results of the questionnaires targeted to flake producers showed that no testing methods on PCR PET flake were standardized and there were critical factors to the quality such as moisture content, contaminants, and viscosity. Case studies of US, Japan and other countries had been done especially about testing methods and 76 samples from 21 companies were tested according to those methods. Based on the results, the final factors were decided as contaminants, moisture content, alkalinity index and intrinsic viscosity. There is a plan to standardize testing methods and they could be guidelines to improve the business competitiveness of PCR PET flake in South Korea.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.34.2-34.2
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• 2011

The demand for Ru has been increasing in the electronic, chemical and semiconductor industry. Chemical mechanical planarization (CMP) is one of the fabrication processes for electrode formation and barrier layer removal. The abrasive particles can be easily contaminated on the top surface during the CMP process. This can induce adverse effects on subsequent patterning and film deposition processes. In this study, a post Ru CMP cleaning solution was formulated by using sodium periodate as an etchant and citric acid to modify the zeta potential of alumina particles and Ru surfaces. Ru film (150 nm thickness) was deposited on tetraethylorthosilicate (TEOS) films by the atomic layer deposition method. Ru wafers were cut into $2.0{\times}2.0$ cm pieces for the surface analysis and used for estimating PRE. A laser zeta potential analyzer (LEZA-600, Otsuka Electronics Co., Japan) was used to obtain the zeta potentials of alumina particles and the Ru surface. A contact angle analyzer (Phoenix 300, SEO, Korea) was used to measure the contact angle of the Ru surface. The adhesion force between an alumina particle and Ru wafer surface was measured by an atomic force microscope (AFM, XE-100, Park Systems, Korea). In a solution with citric acid, the zeta potential of the alumina surface was changed to a negative value due to the adsorption of negative citrate ions. However, the hydrous Ru oxide, which has positive surface charge, could be formed on Ru surface in citric acid solution at pH 6 and 8. At pH 6 and 8, relatively low particle removal efficiency was observed in citric acid solution due to the attractive force between the Ru surface and particles. At pH 10, the lowest adhesion force and highest cleaning efficiency were measured due to the repulsive force between the contaminated alumina particle and the Ru surface. The highest PRE was achieved in citric acid solution with NaIO4 below 0.01 M at pH 10.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.2
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• pp.73-81
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• 2013

Purpose: The purpose of this study was to evaluate the effect of surface treatment on the shear bond strength of zirconia ceramic to 3 resin cements. Materials and methods: A total of 143 disk-shaped Zirconia blocks (HASS Co., Gangneung, Korea) were randomly divided into three treatment groups: (1) only 50 ${\mu}m$ $Al_2O_3$ sandblasting, (2) 50 ${\mu}m$ $Al_2O_3$ sandblast and zircona liner, (3) 50 ${\mu}m$ $Al_2O_3$ sandblasting and Rocatec (3M ESPE, Seefeld, Germany). Bistite II (Tokuyama Dental Co., Japan), Panavia F (Kuraray Medical, Japan), and Superbond C&B (Sun Medical, Japan) were used to cement onto the zirconia. After 24h of storage in distilled water, shear bond strength was evaluated. High value group was re-tested after thermocycling at 5,000 cycles(5-$55^{\circ}C$). Shear bond strength data were analyzed with one-way ANOVA, two-way ANOVA test and Post Hoc Test (${\alpha}$=.05). Shear bond strength data before and after thermocycling were analyzed with Independent sample T test (${\alpha}$=.05). Results: Super-bond C&B treated with Rocatec showed the most high shear bond strength. Super-bond C&B groups resulted in significantly higher than other cement groups (P<.05). Rocatec groups resulted in significantly higher than other surface treatment groups (P<.05). Shear bond strength has increased in Panavia F treated with Zirconia liner (P<.05). After thermocycling, shear bond strength was increased in Super-bond C&B treated with Rocatec but decreased in other groups (P<.05). Conclusion: Super-bond C&B cement resulted the highest shear bond strength and Rocatec system enhanced the shear bond strength. After thermocycling, shear bond strength has decreased in most resin cements except Super-bond C&B treated with Rocatec.

• Journal of the Korean Ceramic Society
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• v.49 no.4
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• pp.380-384
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• 2012

This paper deals with the recent developments of high thermal conductivity silicon nitride ceramics. First, the factors that reduce the thermal conductivity of silicon nitride are clarified and the potential approaches to realize high thermal conductivity are described. Then, the recent achievements on the silicon nitride fabricated through the reaction bonding and post sintering technique are presented. Because of a smaller amount of impurity oxygen, the obtained thermal conductivity is substantially higher, compared to that of the conventional gas-pressure sintered silicon nitride, while the microstructures and bending strengths are similar to each other between these two samples. Moreover, further improvement of the thermal conductivity is possible by increasing ${\beta}/{\alpha}$ phase ratio of the nitrided sample, resulting in a very high thermal conductivity of 177 W/($m{\cdot}K$) as well as a high fracture toughness of 11.2 $MPa{\cdot}m^{1/2}$.

• Korean Institute of Interior Design Journal
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• v.14 no.2 s.49
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• pp.153-160
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• 2005

The purpose of this study was to clarify residential satisfaction of the Living Environment according to responses of staffs in the Horsing Homes. For this, the data about residential satisfaction of the Living Environment of elderly with dementia were taken from the staffs in 2 nursing homes in Tokyo by the questionnaire. Additional information was collected by interviews and observation. It was impossible that the elderly with dementia answered their satisfaction and needs of spaces. For this reason, staffs who care the elderly with dementia during 24 hours and interact with the elderly with dementia were selected the subjects of this survey. Survey question asked for the general features of the staffs, satisfaction, dissatisfactory spaces and the reasons about dissatisfaction of the elderly with dementia. The data were analyzed using the frequency, percentage, crosstab, paired t-test with SPSS 11 program. The result of this study was as follows. First, most of the elderly with dementia were unsatisfied with their bedrooms and bathrooms in bedrooms. Second, the unsatisfied spaces among the living environment were bedroom, bathroom in bedroom, dining room, day corner, special activity room, common bathroom with mechanical bath, and dressing room. The reasons of the unsatisfied spaces were size, comfort, non-existence of the space, and noise in the space.

• Journal of the Korean Society of Safety
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• v.25 no.5
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• pp.27-32
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• 2010

This study is to investigate and compare domestic hazardous toys with harmful substances with foreign toys so that we can find out management criteria for in cognitive infants. Actually, commercially used toys have been collected and tested to find out more effective management standard. it is tried to produce evaluation criteria of environmentally harmful substance but variety of product is needed for overcoming actual barrier due to lot of difficulty huge cost, time, objectiveness. Therefore, This study does not cover all the above. Establishment of evaluation criteria for product harmfulness made by Government or Local government should be continued to improve. Foreign reference material for toy product in Europe, USA, Japan have been investigated and domestic product have been collected and tested for containing heavy metals, formaldehyde, phthalate in the study. All the test have been made in accordance with KSM ISO 2124 to measure heavy metal transfer into body. Toy product used for the study have been purchased in the real market and some of them contains harmful elements with over standard. Post management system such as RAPEX to control periodically should be established for plastic toy with low quality product.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.217-221
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• 2009

With the increase in individual income and leisure time, those urban residents who want to stay in farmland on weekend are being increased. On the contrary, rural economic situation is getting worse due to the lack of labor and income. For this, as a win-win strategy between urban and rural life, a Kleingarten(below 'KG') has been attracted by local government such as Kyunggi prefecture in Korea. This article exam the situation of KG, a weekend farm where one can stay the night in a log cabin, from the perspective of Multi-habitation. For this purpose, this study surveyed four KG areas; two cases at Yangpyung and Yeonchoen in Korea, the rest are at Kasama and Yachiyo in Japan. The findings are as following. First, a standard regulation for the application and management of users in KG should be established as soon as possible. Second, the exchange between users in KG and local residents around KG should be activated in terms of well organized exchange program. Third, a sufficient budget by public sectors or an economic scheme where private sectors can participate in this program should be arranged. Lastly, a use of post occupancy should be well managed by user themselves in KG and well monitored by supervisor of KG simultaneously.

• Journal of Korean Biological Nursing Science
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• v.7 no.1
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• pp.15-28
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• 2005

Purpose: With post-Genome Project, nurses must be able to incorporate genetic knowledge into their practice. The purpose of the present study aimed at providing the basic information needed to establish an education program for the training of nurses specialized in genetic counseling by comparing and analyzing the education contents in genetics of the various domestic and foreign nursing education institutions, identifying the problems of the existing programs, and investigating the current state of domestic genetic counseling programs. Result: The results of literature review were summarized as follows: Common curricula contents in Korea, Japan and U.S.A. were basic genetic knowledge, genetic counseling and prenatal diagnosis. However, In Korea the curriculum was not included legal, ethical, and social issues. In U.S.A. the course was focused on health promotion related to genetics. The expanded role of nurses is to provide the genetic counseling for clients and their families. So, this articles provided a sample of the new genetic counseling program for nurses which are included basic genetics, genetic counseling, nurse's role and knowledge, legal, ethical, social issues and practicum. Conclusion: this study suggests that this educational program is to brought up genetic specialized nurses in the master's course in the near future.

• Earthquakes and Structures
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• v.7 no.6
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• pp.1187-1221
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• 2014

The uplifting and rocking of slender, free-standing structures when subjected to ground shaking may limit appreciably the seismic moments and shears that develop at their base. This high-performance seismic behavior is inherent in the design of ancient temples with emblematic peristyles that consist of slender, free-standing columns which support freely heavy epistyles together with the even heavier frieze atop. While the ample seismic performance of rocking isolation has been documented with the through-the-centuries survival of several free-standing ancient temples; and careful post-earthquake observations in Japan during the 1940's suggested that the increasing size of slender free-standing tombstones enhances their seismic stability; it was George Housner who 50 years ago elucidated a size-frequency scale effect that explained the "counter intuitive" seismic stability of tall, slender rocking structures. Housner's 1963 seminal paper marks the beginning of a series of systematic studies on the dynamic response and stability of rocking structures which gradually led to the development of rocking isolation-an attractive practical alternative for the seismic protection of tall, slender structures. This paper builds upon selected contributions published during this last half-century in an effort to bring forward the major advances together with the unique advantages of rocking isolation. The paper concludes that the concept of rocking isolation by intentionally designing a hinging mechanism that its seismic resistance originates primarily from the mobilization of the rotational inertia of its members is a unique seismic protection strategy for large, slender structures not just at the limit-state but also at the operational state.