• 대한치과기공학회지
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• 제31권3호
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• pp.27-34
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• 2009

This study compared and analyzed changes to the mechanical characteristics to nonprecious metal alloy for porcelain fused to metal crowns when it's repetitively used without the addition of new alloy. Metal samples were made with the Verabond V nonprecious metal alloy. Those samples to measure tensile and yield strength were made in the standardized design(ISO 22674), those to measure bond strength in the $25mm{\times}3mm{\times}0.5mm$ format, and those to measure hardness in the $10mm{\times}10mm{\times}1mm$ format. A ceramic to measure bond strength was made at the center of the metal sample in the length of $8{\ss}{\AE}$ by using Noritaker Super Porcelain EX-3. Ten samples were prepared for one, three and five repetitions of casting each. The test results were as follows: 1. The more casting was repeated, the more significantly tensile strength dropped. 2. The more casting was repeated, the more significantly yield strength dropped. 3. Repetitive casting didn't cause significant changes to bond strength. 4. The Vickers hardness significantly fell with increasing repetitions of casting. There were no changes to bond strength observed with the increasing number of repeating casting. But tensile strength, yield strength, and Vickers hardness decreased. Those results indicate that repeated casting can affect durability and that careful attention should be paid by avoiding repetitive use or excessive increase of uses when no new alloy is added.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권3호
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• pp.263-267
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• 2014

Super junction trench gate power MOSFETs have been receiving attention in terms of the trade-off between breakdown voltage and on-resistance. The vertical structure of super junction trench gate power MOSFETs allows the on-resistance to be reduced compared with conventional Trench Gate Power MOSFETs. The heat release of devices is also decreased with the reduction of on-resistance. In this paper, Lattice Temperature of two devices, Trench Gate Power MOSFET and Super junction trench gate power MOSFET, are compared in several temperature circumstance with the same Breakdown Voltage and Cell-pitch. The devices were designed by 100V Breakdown voltage and measured from 250K Lattice Temperature. We have tried to investigate how much temperature rise in the same condition. According as temperature gap between top of devices and bottom of devices, Super junction trench gate power MOSFET has a tendency to generate lower heat release than Trench Gate Power MOSFET. This means that Super junction trench gate power MOSFET is superior for wide-temperature range operation. When trench etching process is applied for making P-pillar region, trench angle factor is also important component. Depending on trench angle, characteristics of Super junction device are changed. In this paper, we focus temperature characteristic as changing trench angle factor. Consequently, Trench angle factor don't have a great effect on temperature change.

• 한국치위생학회지
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• 제3권2호
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• pp.183-196
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• 2003

Purpose: This study sought to identify factors associated with dental hygienists' decisions to leave one dental office and commence practice in another. In addition to, the reasons dental hygienists stay in the profession were investigated. Demographic descriptors, including education level, marital status and age, and employment setting were also examined. Methods: Currently practicing dental hygienists in Korea were surveyed from March to May 2003. Data were collected through a questionnaire. The survey collected information concerning the 461 respondents' personal characteristics and reasons associated with changing positions and staying. Data were analyzed using frequency distributions, independent t-tests and chi-square analyses. All statistical analyses were conducted using the Statistical Package for Social Scientists(SPSS v.10, Chicago, Illinois). Results: The primary reasons for taking up another employment were found to be better offer, inadequate salary and personal conflict with dentist. Secondary reasons stated for changing their job revealed additional factors including inadequate salary, better offer, and lack of benefits. The primary influence in deciding to remaining in the practice of dental hygiene was self-development. Family responsibility, safe environment and professional collaboration were also important factors in deciding to remain in workforce. Conclusion: The position changes of dental hygienists are primarily influenced by better offer. Inadequate salary and conflict with dentist were also important factors in deciding to change employment positions. The findings suggest that dental hygienists who remain in the workforce are positively influenced mainly by self-development. Employers of dental hygienists should be aware of these factors in employing process. If more hygienists could remain longer in their positions, the manpower situation would be affected positively.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권1호
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• pp.22-29
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• 2006

We demonstrate highly manufacturable Multi-channel Field Effect Transistor (McFET) on bulk Si wafer. McFET shows excellent transistor characteristics, such as $5{\sim}6 times higher drive current than planar MOSFET, ideal subthreshold swing, low drain induced barrier lowering (DIBL) without pocket implantation and negligible body bias dependency, maintaining the same source/drain resistance as that of a planar transistor due to the unique feature of McFET. And suitable threshold voltage ($V_T$) for SRAM operation and high static noise margin (SNM) are achieved by using TiN metal gate electrode.

• Asian-Australasian Journal of Animal Sciences
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• 제15권12호
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• pp.1790-1797
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• 2002

Lactic acid bacteria were isolated from piglets and chicken and characterized. Lactic acid bacteria showing resistance to low pH and bile, adhesion to intestinal epithelium cells, and the inhibition of Escherichia coli and Salmonella spp. were identified as Lactobacillus acidophilus. L. acidophilus PF01 survived for 2 h in MRS broth adjusted to pH 2. L. acidophilus CF07 was less resistant than L. acidophilus PF01 to pH 2, but survived at pH 2.5 for 2 h. Both of isolates were able to grow in MRS broth containing 0.3% (w/v) bile, with L. acidophilus CF07 being more tolerant to bile than L. acidophilus PF01. L. acidophilus PF01 and CF07 adhered specifically to the duodenal and jejunal epithelium cells of piglet, and the cecal and duodenal epithelium cells of chicken, respectively. Both of isolates did not adhere to the epithelium cells of the various animal intestines from which they were isolated. When L. acidophilus was cultured with E. coli and Salmonella spp. in MRS broth, MRS broth containing 2% skim milk powder or modified tryptic soy broth at $37^{\circ}C$, L. acidophilus PF01 and CF07 inhibited the growths of E. coli K88 and K99, and S. enteritidis and S. typhimurium, respectively. Both of isolates were found to possess the essential characteristics of probiotic lactic acid bacteria for piglet and chicken.

• Asian-Australasian Journal of Animal Sciences
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• 제19권3호
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• pp.309-314
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• 2006

The present investigation was undertaken to study the milkability characteristics of Holstein cows. Out of 6,660 initial records 4,607 records were finally included in the analysis after deleting some records with an abnormal range of values for the traits considered. These 4,607 Holstein cows belonged to a total of 122 herds located in a province in Korea. The 'LactoCorder' instrument was used to electronically record the milkability traits at the milking parlor. A total of 19 traits were studied which were broadly classified into milk yield, milking speed, milking time and the electrical conductivity related traits. The SAS 9.1 statistical software was used to carry out analyses. The average maximum milk flow per minute was 3.21 kg/min, while the average milking speed during the main milking process (DMHG) had a mean value of 2.30 kg/min. The total milk yield was 14.14 kg, 62% of which was milked during the first three minutes of the milking. The average total milking time was 8.23 min. Among the three phases of the main milking process, the time of stable milk flow had the longest time (2.97 min) followed by the time at the decline phase (2.62 min). The average time taken to reach the plateau phase was 1.08 min, which can still be reduced further through improved managemental practices. Among milk yield traits, milk yield during the first two (MG2) and three (MG3) minutes of milking had high positive correlation with milking speed traits and negative correlations with almost all the milking time traits except time of incline in milk flow from 0.5 kg/min till the attainment of the plateau phase (tAN). Milking speed traits had negative correlations with total milking time, time at main milking process, time at plateau and with the time at decline. Since there was medium to high negative correlation between the milking speed and the time at plateau, there is a need for selection of cows which have intermediate milking speed so that it could require less milking time and also the optimum (higher and longer) plateau time. Proper pre-stimulation and avoiding over milking will help in further reducing the milking time and thus will add to the net profit of the farmer.

• KSBB Journal
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• 제15권2호
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• pp.201-207
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• 2000

전통적으로 사용되어 왔던 점토의 숙성과정을 과학적으로 규명하였고, 철환원세균의 농화배양액을 이용하는 생명공학기술을 이용한 개량된 점토 숙성방법을 연구하였다. 전통적으로 사용되어 왔던 수비법에 의한 점토의 숙성은 토착 미생물들이 점토에 함유된 유기물을 분해하는 과정에서 철불순물을 점토로부터 제거하여 색상을 향상시킬 뿐만 아니라 점토의 점성과 가소성 및 강도를 증진시키는 효과가 있음을 알 수 있었다. 점토숙성용 철환원세균 농화배양액을 얻는 방법을 제시하였고, 점토에 탄소원을 첨가한 후 혐기적 조건에서 농화배양액을 이용한 점토 숙성 방법을 제시하였다. 생물공학기술을 활용한 개량점토 숙성법은 전통적인 점토 숙성에서 소요되는 점토의 처리 시간을 약 1/6 수준이하로 단축시킬 수 있었고, 점토로부터 철불순물을 보다 효과적으로 제거할 수 있었을 뿐만 아니라 전통적인 방법보다도 물성이 우수한 점토로 고품위화가 가능하였다.

• 한국의류학회지
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• 제41권3호
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• pp.501-516
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• 2017

Skin colors of females between the ages of 25-35 from Korea, China, and Vietnam were measured in Seoul, Beijing, and Hanoi using the Minolta CM-600d spectrophotometer. CIE Lab and Munsell HVC data of the face (forehead and both cheeks) and body (neck and arm) were analyzed using t-test, Analysis of Variance (ANOVA), Duncan's Multiple Range Test, Linear Regression Analysis, and K-Means Cluster Analysis using SPSS software. Korean females showed the highest L and V values for the face and body; Vietnamese females showed the highest b value in the face and the highest a value in the body. Higher L and b values for the face were related to higher L and b values of the body; this relationship was more prominent in Korean females. The younger age group (25-29) showed higher L values and lower b values than the older age group (30-35). Females from Korea, China, and Vietnam were grouped into Type 1 and Type 2 based on skin color. Type 1 had darker skin with more redness and yellowness and Type 2 had lighter skin with less redness and yellowness. A total of 88.2% of Korean females belonged to Type 2, 80.4% of Vietnamese females were Type 1, and Chinese females indicated an even distribution of Type 1 and Type 2.

• 한국축산시설환경학회지
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• 제19권2호
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• pp.155-162
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• 2013

The objective of this study is to investigate the effects of Cynanchum wilfordii (CW) on cell viability, anti-oxidant activity, volatile fatty acid (VFA) production and methane gas production. Collected rumen fluid incubated with CW powder (1% w/v) for 12 and 24 hours were analyzed for pH, VFAs and methane. Alamar blue assay showed no significant difference on the viability of 3T3-L1 and C2C12 cells treated with CW for 24 hours. TBARS data showed a dose dependent increase on the antioxidant activity of CW. VFAs increased in the CW-treated groups compared to the control group. In addition, propionate increased more than other VFAs by the treatment with CW. There was a significant decrease in methane gas production in batch culture treated with CW in 12hrs. In conclusion, it was suggested that Cynanchum wilfordii could manipulate rumen fermentation considered by increasing VFA production and inhibition of methanogenesis.

• 대한지역사회영양학회지
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• 제18권5호
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• pp.457-466
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• 2013

This study was conducted to investigate the effect of breastfeeding education experience on knowledge, control beliefs, and future intention toward breastfeeding to consider the needs of breastfeeding education program of university students. The breastfeeding knowledge, control beliefs and related habits of 445 male and female college students were evaluated between September 1, 2011 to April 30, 2012. Data were collected from self-administered questionnaires and analyzed using SPSS for Window V.17.0. ${\chi}^2$-test, t-test and ANOVA were used for the calculation of differences between groups. The percentage of students who intended to breastfeed their baby was 80.7% (male: 73.6%, female: 84.2%). Only 21.6% of students experienced breastfeeding education. Students planned to get information related to breastfeeding from their mothers (32.4%), breastfeeding experts (23.8%) and Medical doctors & nurses (10.6%). breastfeeding education group showed higher knowledge level (14.46 vs 10.56) and control beliefs (3.48 vs 3.16) to breastfeeding than non-education group (p < 0.001). General attitude toward breastfeeding was similar between groups; the specific intention to breastfeed for 6 months was higher in the education group (83.3% vs 58.2%) (p < 0.01). Percentage of students who gave correct answers to knowledge questions related to breastfeeding was also higher in the breastfeeding education group than non-education group (72.3% vs 52.8%). Among 20 questions, only 2 questions showed no significant differences between the groups. These findings suggested that breastfeeding education was effective in encouraging or improving breastfeeding practices.