• Elastomers and Composites
• /
• v.44 no.3
• /
• pp.269-273
• /
• 2009

A study on the life-time expectation of a CR-modified NR rubber composite through the change of thermal degradation characteristics was performed using both isothermal thermogravimetric analysis (TGA) and thermomechanical analysis (TMA). Master curves at reference temperature of $90^{\circ}C$ could be obtained with shift factor $a_T$, which was determined empirically using Time-Temperature Superposition Principle (TTSP). Activation energies could be calculated from the slope of Arrhenius plot of shift factor and showed similar values of $E_{a,TGA}$= 41.2 and $E_{a,TMA}$= 54.5 kJ/mol, respectively. It was considered from the results that chemical degradation resulting weight loss of the sample might be closely related to a physical degradation such as the dimensional change of the sample.

• Proceedings of the SCSK Conference
• /
• 2003.09b
• /
• pp.253-267
• /
• 2003

Inositol and phytic acic extracted from rice bran were investigated for applying cosmetics. Skin lotions containing 0∼3.0wt% inositol and 0∼1.5wt% phytic acid were applied respectively, to the arm skins of 45 Asian women 20'-40's for 7 weeks. Improvement on moisture was evaluated. In addition, improvements on sebum, elasticity, and wrinkle were examined after applying placebo, Inositol and phytic acid-containing skin lotions for face, respectively. For 1.0 wt% inositol resulted in 19% increase of moisture. The wrinkle reduction and elasticity improved 12.4% and 17.0% on average, respectively. Applying 0.5wt% phytic acid resulted in 71.6% increase the moisture. Improvements on wrinkle and elasticity were 15.9% and 21.9% respectively. Applying inositol or phytic acid regardless of dry or oily, resulted in sebum value recovery to that of the normal skin after 2- 4 weeks. Inositol is inferior to phytic acid in improvenients of the skin, and phytic acid is not suitable to sensitive skin. So 0-0.5wt% of phytic acid were added to 1.0wt% inositol and similar experiments were carried out. In case of added 0.1wt% phytic acid, moisture increased 63.8% approximately. Improvements on elasticity and reduction on wrinkle were 17.2% and 17.4%, respectively. Both skin types were turned to normal skin type after 2 weeks. It could improve the skin condition when used inositol added phytic acid. The optimized concentration of phytic acid was 0.10wt% with 1.0wt% of inositol for synergic effect.

• Food Science and Preservation
• /
• v.14 no.4
• /
• pp.394-399
• /
• 2007

In this study, the characteristic qualities of whole soymilk were examined based on differing hydrolysis condition. The results showed that as the concentration of enzyme preparation(KMF-G) increase, $^{\circ}Brix$, calcium-binding capacity, and the content of free amino acid components also increased. Additionally SDS-PAGE analysis revealed a similar pattern of in the molecular weight of proteins at enzyme preparation concentration 0.20 and 0.35%(w/w). The quality of whole soymilk hydrolysate was shown to be best at a enzyme preparation(KMF-G) concentration of 0.20%(w/w) and hydrolysis time of 60 min. When sterilized at 115, 130 and $145\;^{\circ}C$ for 15 sec each the change in whole soymilk quality was not substantial. Based on the above results, a 0.20%(w/w) enzyme preparation(KMF-G) concentration and 60 mim hydrolysis time was determined to be the optimal hydrolysis condition for whole soymilk. It is anticipated that soymilk hydrolysis will a food material that is diverse in its application and uses.

• Korean Journal of Plant Resources
• /
• v.15 no.2
• /
• pp.128-134
• /
• 2002

Content of crude protein in both pileus and stalk increased progresively as growth period became longer and then decreased at old stage. Contents of ash and reducing sugars followed the same trend as that of the crude protein. However, content of crude lipid decreased as growth progressed more. Seventeen kinds of amino acid were detected in Lentinula. Content of total amino acid increased as mushroom grew more, but decreased after old stage. The amino acid such as Glu, His, Gly and Ala were contained with relatively large amount in Lentinula. Content of free amino acid showed the similar trends as that of total amino acid. Contents of most of the mineral increased as growth period progressed, but K content decreased as growth period became longer. Contents of K and P were much higher than contents of other mineral. The major fatty acid contained in Lentinula were linoleicacid, palmitic acid and oleic acid. The large amount of volatile component in Lentinula was 1-octen-3-ol, so that this material was speculated to be major source of perfume. Other perfumic materials such ethyl acetate, 3-octanone, ethanol, (E)-2-octenal, 4-octen-3-one, acetaldehyde, ethyl formate were also contained in Lentinula, especially in pilous.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.4
• /
• pp.67-72
• /
• 1989

Room Temperature Plasma Nitridation of silicon was investigated as a new LOCOS (local oxidation of silicon) process in order to reduce the bird's beak length. In $N_2$ plasma formed by 100kHz, 400W AC power, a thin silicon nitride film (<100${\AA}$) was uniformly grown on a silicon substrate. SEM studies showed that the nitride layer formed by this method can effectively protect the silicon from oxidation and reduce the bird's beak length to $0.2{mu}m$ when 4000${\AA}$ field oxide is grown. This is a considerable improvement comparing with 0.7${mu}m,$ the bird's beak, for the conventional LOCOS process using a thick LPCVD nitride. No appreciable crystalline defect could be found around the bird's beak with SEM cross-section afrer Secco etch. Leakage current tests were carried out on the $N^+/P^-$ well and $P^+/N^-$ well diodes formed by this new LOCOS process. The electrical tests indicate that this new process has electrical properties similar or superior to those of the conventional LOCOS process.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.17 no.3
• /
• pp.371-381
• /
• 2010

Purpose: The purpose of this study was to develop a scenario and evaluate students' performance in simulation learning of care for patients with asthma in emergency units. Methods: Meetings of experts were used to develop a scenario based on actual patients and textbook material. An evaluation protocol was developed to evaluate the simulation learning. The scenario was used in 2006 with six groups of 26 senior nursing students who participated voluntarily. Results: The scenario was developed according to the nursing process for 15 minutes of simulation learning. The nursing students were able to demonstrate their knowledge and skills. The results showed a need to improve problem solving ability. In the self-evaluation, the students reported that simulation learning helped them to integrate their knowledge to practice and recognize their weaknesses and strengths. However, the scores for self-confidence about patient care after the simulation learning were low (4.8/10). Conclusion: The scenario in this study gave the students the experience of providing qualified and secure nursing care under conditions similar to reality. Further development of a variety of scenarios for simulation learning is needed.

• Publications of The Korean Astronomical Society
• /
• v.30 no.2
• /
• pp.219-221
• /
• 2015

We present our recent observations of SDSS J102102.25+174439.9, a new eclipsing white dwarf - main sequence WDMS binary with an orbital period of 0.14 days. This system belongs to the post common-envelope binary group as shown by the spectrum from the Sloan Digital Sky Survey. We obtained our data using the ULTRASPEC instrument installed on the 2.4-m telescope at the Thai National Observatory (TNO). Our multi-band observations reveal an unusual and persistent drop in brightness after the primary eclipse. These dips, which appear to show variations in amplitude, also have a complex shape that changes within days. Dips in WDMS systems have been observed on only one other occasion, in the light curve of QS Vir prior to the eclipse of the white dwarf. The dips in SDSS J1021+1744 are unique because they are present at different wavelengths and they occur approximately at similar phases. Hosting a DA white dwarf and an M4 companion star, this system is known to be the only WDMS to show these kind of dips in its light curve. It is possible that these dips are caused by ejected materials from an active companion star, such as in QS Vir. The light curve in the g' filter exhibits deep and narrow features, implying that the material which passes in front of the white dwarf in SDSS J1021 must be dense and small in size. Furthermore, we try to constrain the stellar and orbital parameters of SDSS J1021+1744 using the Binary Maker 3 software. We use g' and r' data for our light curve analysis to have a better approximation for the red dwarf star.

• The Journal of Korean Academy of Prosthodontics
• /
• v.41 no.6
• /
• pp.762-771
• /
• 2003

Statement of problem. In dentistry, the minimally prepared inlay resin-bonded fixed partial denture (FPD) made of new ceromer / fiber-reinforced composite (FRC) was recently introduced. However, the appropriate dimensions for the long-term success and subsequent failure strength are still unknown. Purpose. The aim of this study was to investigate the most fracture-resistible thickness combination of the ceromer / FRC using a universal testing machine and an AE analyzer. Material and Methods. A metal jig considering the dimensions of premolars and molars was milled and 56-epoxy resin dies, which had a similar elastic modulus to that of dentin, were duplicated. According to manufacturer's instructions, the FRC beams with various thicknesses (2 to 4 mm) were constructed and veneered with the 1 or 2 mm-thick ceromers. The fabricated FPDs were luted with resin cement on the resin dies and stored at room temperature for 72 hours. AE (acoustic emission) sensors were attached to both ends, the specimens were subjected to a compressive load until fracture at a crosshead speed of 0.5 mm/min. The AE and failure loads were recorded and analyzed statistically. Results. The results showed that the failure strength of the ceromer/FRC inlay FPDs was affected by the total thickness of the connectors rather than the ceromer to FRC ratio or the depth of the pulpal wall. Fracture was initiated from the interface and propagated into the ceromer layer regardless of the change in the ceromer / FRC ratio. Conclusion. Within the limitations of this study, the failure loads showed significant differences only in the case of different connector thicknesses, and no significant differences were found between the same connector thickness groups. The application of AE analysis method in a fiber-reinforced inlay FPD can be used to evaluate the fracture behavior and to analyze the precise fracture point.

• The Journal of Advanced Prosthodontics
• /
• v.1 no.1
• /
• pp.26-30
• /
• 2009

STATEMENT OF PROBLEM. Qualitative and semi-quantitative methods have been developed for TMJ sound classification, but the criteria presented are completely inhomogeneous. Thus, to develop more objective criteria for defining TMJ sounds, electroacoustical systems have been developed. We used Joint vibration analysis in the BioPAK system(Bioresearch Inc., Milwaukee, USA) as the electrovibratography. PURPOSE. The aim of this study was to examine the TMJ sounds with repect to frequency spectra patterns and the integral > 300 Hz /< 300 Hz ratios via six-months follow-up. MATERIAL AND METHODS. This study was done before and after the six-months recordings with 20 dental school students showed anterior disk displacement with reduction. Joint vibrations were analyzed using a mathematical technique known as the Fast Fourier Transform. RESULTS. In this study Group I and Group II showed varied integral > 300 /< 300 ratios before and after the six-months recordings. Also, by the comparative study between the integral > 300 /< 300 ratios and the frequency spectrums, it was conceivable that the frequency spectrums showed similar patterns at the same location that the joint sound occurred before and after the six-months recordings. while the frequency spectrums showed varied patterns at the different locations that the joint sound occurred before and after six-month recordings, it would possibly be due to the differences in the degree of internal derangement and/or in the shape of the disc. CONCLUSIONS. It is suggested that clinicians consider the integral > 300 /< 300 ratios as well as the frequency spectrums to decide the starting-point of the treatment for TMJ sounds.

• Journal of Periodontal and Implant Science
• /
• v.37 no.4
• /
• pp.849-857
• /
• 2007

Purpose: The purposes of this study were to compare and quantify the expressions of RANK and RANKL in the gingival tissues of non-periodontitis patient and patients with chronic periodontitis, in order to understand the contribution of these proteins to periodontal destruction. Material and methods: Gingival tissue samples were obtained during periodontal surgery or tooth extraction. According to the patient's systemic condition & clinical criteria of gingiva, each gingival sample was divided into two groups. Group 1 (n=8) is clinically healthy gingiva without bleeding and no evidence of bone resorption or periodontal pockets, obtained from non-periodontitis patients. Group 2 (n=8) is inflammed gingiva from patients with chronic periodontitis. Tissue samples were prepared and analyzed by Western blotting. The quantification of RANK and RANKL were performed using a densitometer and statistically analyzed by Student's t-Test. Results: The expression of RANK were similar in group 1 and 2. The difference between group 1 and 2 was not statistically significant. And the mean amount of RANKL was more increased in group 2 than group 1. The difference between group 1 and group 2 was statistically significant. Conclusion: The expression level RANK didn't show any significant difference between healthy tissue from non-periodontitis patients and inflamed tissue from chronic periodontitis, but the expression level of RANKL in inflammed tissue from chronic periodontitis showed significantly increased tendency compared to healthy gingiva from non-periodontitis patients. Therefore, characteristics of RANK and RANKL in progress of chronic periodontitis would be basis of further studies in diagnostic method and treatment index of the disease.