• Composites Research
• /
• v.15 no.4
• /
• pp.23-31
• /
• 2002

The two dimensional size effect of specimen gauge section ($length{\;}{\times}{\;}width$) was investigated on the compressive behavior of a T300/924 $\textrm{[}45/-45/0/90\textrm{]}_{3s}$, carbon fiber-epoxy laminate. A modified ICSTM compression test fixture was used together with an anti-buckling device to test 3mm thick specimens with a $30mm{\;}{\times}{\;}30mm,{\;}50mm{\;}{\times}{\;}50mm,{\;}70mm{\;}{\times}{\;}70mm{\;}and{\;}90mm{\;}{\times}{\;}90mm$ gauge length by width section. In all cases failure was sudden and occurred mainly within the gauge length. Post failure examination suggests that $0^{\circ}$ fiber microbuckling is the critical damage mechanism that causes final failure. This is the matrix dominated failure mode and its triggering depends very much on initial fiber waviness. It is suggested that manufacturing process and quality may play a significant role in determining the compressive strength. When the anti-buckling device was used on specimens, it was showed that the compressive strength with the device was slightly greater than that without the device due to surface friction between the specimen and the device by pretoque in bolts of the device. In the analysis result on influence of the anti-buckling device using the finite element method, it was found that the compressive strength with the anti-buckling device by loaded bolts was about 7% higher than actual compressive strength. Additionally, compressive tests on specimen with an open hole were performed. The local stress concentration arising from the hole dominates the strength of the laminate rather than the stresses in the bulk of the material. It is observed that the remote failure stress decreases with increasing hole size and specimen width but is generally well above the value one might predict from the elastic stress concentration factor. This suggests that the material is not ideally brittle and some stress relief occurs around the hole. X-ray radiography reveals that damage in the form of fiber microbuckling and delamination initiates at the edge of the hole at approximately 80% of the failure load and extends stably under increasing load before becoming unstable at a critical length of 2-3mm (depends on specimen geometry). This damage growth and failure are analysed by a linear cohesive zone model. Using the independently measured laminate parameters of unnotched compressive strength and in-plane fracture toughness the model predicts successfully the notched strength as a function of hole size and width.

• The Korean Journal of Pesticide Science
• /
• v.6 no.1
• /
• pp.16-24
• /
• 2002

Research trends in the measurement of foliar uptake of pesticides and the recently proposed action mechanism of the surfactant-induced uptake of pesticides were reviewed with the related reports and studies. Major techniques used in those fields are bioassay, radiotracer techniques with leaves or cuticular membrane. Recently, a new method using Congo Red as a tracer was proposed. The limiting factor in the pesticides uptake into leaves is the waxy layer which consists of the epicuticular and cuticular wax. Physico-chemical parameters such as molar volume, water solubility and partition coefficient of pesticides have limited influences on the pesticide uptake into leaves. Polydisperse ethoxylated fatty alcohol surfactants are well known as the good activator for many pesticides. It is now generally agreed that uptake activation is not related to the intrinsic surface active properties of surfactants such as surface activity, solvent property, humectancy and critical micelle concentration. Recent studies using ESR-spectroscopy revealed that the surfactants have an unspecific plasticising effect on the molecular structure of the wax and cuticular matrix, leading to increased mobilities of pesticides. Penetration of surfactants into waxy layer altered the pesticide mobility in wax and the partition coefficient of pesticide, and then the pesticides penetration into leaves was enhanced temporally. The enhancing effect of surfactant could be significantly different depending on the carbon number of aliphatic moiety and the number of ethoxy group in polyoxyethylene chain of surfactants. It is suggested that the rate of penetration of surfactants should have a significant relationship with the rate of penetration of pesticides.

• Cartoon and Animation Studies
• /
• s.40
• /
• pp.367-395
• /
• 2015

Mobile games have taken 80% of the market sales in smart device application industry that is highly regarded as one of the fast growing pool of cultural content after the distribution of smart devices. One of the most successful mobile games after the smart device's appearance is . created by Gung-ho Online entertainment under Softbank Japan, has gained the sales revenue of one trillion dollars after its release in 2012, just after one year of its exposure to the market. The game also has been the top rank by Worldwide Mobile Game Revenues for 2years achieving 40 million downloads worldwide in 2015. However, there is no place for a Korean game in world mobile game sales ranks yet. Even though the mobile game industry has been expanding every year, Korean games are losing its places in the market. Therefore, the analysis of a successful game such as is vital for diagnosing Korea's game content and its lack of direction. This study utilizes K. Masanao's Matrix for Creating Profit System for analyzing 's factors for its success. First, the game has incorporated puzzle and RPG contents for creating a new genre, which led various age groups to play the game. Second, the developers have applied 'limited time' in-game festivals and collaborations between the game and famous contents such as God Festival and Character Draw system to increase the profit revenue. Third, the company communicated with on and off line players to seek their needs for developing the game's better development. Consequently, the three success factors of deduced from this study not only reflect the related researches and academic values, but also contribute for the search in finding better ways to developing game contents for Korean mobile game industry.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.15 no.4
• /
• pp.115-124
• /
• 2007

The material compressions in the vertical composting reactor affect to the biodegradation rates of the organic wastes. This study investigated the variations of physical properties of the composting materials according to the height of reactor due to affect to the settlement in the vertical composting reactor. The variations of decreased temperature after peak temperature showed the different patterns depending on the reactor heights. The variation width of re-increased temperature after peak temperature was reduced as the mixing operations were increased, and increased as the height of reactor elevated. The moisture content and the variation width of the moisture content were increased higher as the height of the reactor became higher. The variations of the bulk density at each height of vertical reactor showed the same tendency comparing with those of the moisture content. The relationship between bulk density and moisture content had shown the quadratic equation (r2=0.94). The dry solid contents at each reactor height were decreased as the height of reactor were increased. The results of the variation of the physical properties during the composting process were caused by the downward compression of the material into the reactor. Settlement rate in the vertical composting reactor was estimated about 2.184cm/day. To increase the biodegradation efficiency in the vertical reactor, the conditions of air path in the composting material matrix have to be investigated afterwards.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.12
• /
• pp.1663-1670
• /
• 2012

The inhibitory effects of rose hip (Rosa canina L.) water extracts from two different manufactures on osteoarthritis was comparatively investigated in primary cultures of rat cartilage cells. To identify the effects of rose hip extracts against $H_2O_2$ (300 ${\mu}M$, 2 hr) treatment, cell survival was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell survival increased by rose hip extracts in the range of 100 to 600 ${\mu}g/mL$ of $H_2O_2$ treatment. To determine the anti-inflammatory effects of rose hip extracts, tumor necrosis factor alpha (TNF-${\alpha}$), nitric oxide (NO), and Cox-2 expression were measured after lipopolysaccharide (LPS) activation. TNF-${\alpha}$ level with rose hip extract treatment was decreased by 27.4% and 31.9% at 600 ${\mu}g/mL$ of $H_2O_2$ treatment. Nitric oxide was inhibited by rose hip extract at 100~600 ${\mu}g/mL$ of $H_2O_2$ treatment in a dose-dependent manner. In addition, Cox-2 protein expression was dose-dependently decreased while Cox-1 had no change in expression level. The severity of osteoarthritis is controlled by a balance between anabolic and catobolic factors in an articulation, therefore the expression of these factors plays a critical role in preventing osteoarthritis. In measuring anabolic factors, the genetic expression of collagen type I increased with rose hip treatment, while the genetic expression of collagen II did not change. In addition, the genetic expression of aggrecan (proteoglycan core protein) was significantly increased. while the genetic expression of matrix metalloproteinase (MMP) 3, 7 and 13, known catabolic factors, was significantly inhibited by treatment with rose hip extract. The expression of MMP13 was especially highly influenced. In conclusion, rose hip water extracts show inhibitory effects on cell death by $H_2O_2$ mediated oxidative stress, which is related to inhibitory effects on inflammation due to TNF-${\alpha}$, NO, and Cox-2. The ability of rose hip extracts to ameliorate inflammation in primary cultures of cartilage cells seems to associate with an increased genetic expression of specific anabolic factors, collagen type I and aggrecan, and a decreased expression of catabolic factors, MMPs (3, 7, and 13). However, there were no significant differences between rose hip extracts from the two manufacturers.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.2
• /
• pp.273-284
• /
• 2007

The aim of this study was to evaluate the resistance to degradation and to compare the wear resistance characteristics of four esthetic restorative materials in an alkaline solution(0.1N NaOH). The composite resins studied were Composan LCM flow(Promedica, Germany). Clearfil ST(Kuraray medical, Japan), Durafi VS1(Heraeus Kulzer, U.S.A), Point 4(Kerr, U.S.A). The results were as follows : 1. The mass loss of each brand was $1.02{\sim}6.04%$ and highest value in Durafil VS$(6.04{\pm}0.29%)$. 2. The sequence of the degree of degradation layer depth was in descending order by Durafil VS, Clearfil ST, Point 4 and Composan LCM flow. There were significant differences between Point 4, Composan LCM flow and the others (p<0.001). 3. The sequence of the Si loss was in descending order by Clearfil ST, Durafil VS, Composan LCM flow and Point 4. There were significant differences among the materials (p<0.001). 4. On SEM, destruction of bonding between matrix and filler and on CLSM, the depth of degradation layer of specimen surface was observed. 5. The sequence of maximum wear depth was in descending order by Durafil VS, Composan LCM flow, Point 4 and Clearfil ST. There were no significant differences among the materials (p>0.001) 6. The correlation coefficient between Si loss and degradation layer depth (r=0.892, p<0.01) and Si loss and mass loss(r=0.736, p<0.01) were relatively high. These results indicate that hydrolytic degradation, wear and another factor may consider as evaluation factors of composite resins.

• Journal of Life Science
• /
• v.17 no.8 s.88
• /
• pp.1090-1099
• /
• 2007

Myristicin, l-allyl-3,4-methylenedioxy-5-methoxybenzene, was one of the major essential oils of nutmeg. However, its anti-allergic effect in the Th1/Th2 immune response was poorly understood. Recently, it was shown that T-bet and GATA-3 was master Th1 and Th2 regulatory transcription factors. In this study, we have attempted to determine whether myristicin regulates Th1/Th2 cytokine production, T-bet and GATA-3 gene expression in ovalbumin (OVA)-induced asthma model mice. Myristicin reduced levels of IL-4, Th2 cytokine production in OVA-sensitized and challenged mice. In the other side, it increased $IFN-{\gamma}$, Th1 cytokine production in myristicin administrated mice. We also examined to ascertain whether myristicin could influence eosinophil peroxidase (EPO) activity. After being sensitized and challenged with ovalbumin (OVA) showed typical asthmatic reactions. These reactions included an increase in the number of eosinophils in bronchoalveolar lavage fluid, an increase in inflammatory cell infiltration into the lung tissue around blood vessels and airways, and the development of airway hyper-responsiveness (AHR). The administration of myristicin before the last airway OVA challenge resulted in a significant inhibition of all asthmatic reactions. Accordingly, these findings provide new insight into the immunopharmacological role of myristicin in terms of its effects in a murine model of asthma.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.14 no.1
• /
• pp.101-104
• /
• 2010

Purpose: Raynaud scan is divided to flow, blood pool and local-delay image. Usually, we evaluate comparison through blood pool and local-delay image. We will evaluate about usability when comparative observe blood image and local-delay image in Raynaud scan that used $^{201}Tl$ as making flow image to one sheet of images. Materials and Methods: We have selected 29 Raynaud phenomenon patients aged 14~68 years who visited department of vascular surgery between Feb. 2008 and Aug. 2009. An intravenous injection $^{201}Tl$ of 111 MBq (3 mCi) to opposite side diagonal line limbs above an internal auditing department. Equipment used Philips gamma camera forte A-Z, and collimator used LEHR. Matrix size set up to each $64{\times}64$, $128{\times}128$, $256{\times}256$ and zoom factor used to full field. Protocol of dynamic is 2 second to 155 frames. Blood pool and delay count to 300 second. We set up ROI by a foundation to data acquired in PEGASYS processing program. Each results were analyzed with the SPSS 12.0 statistical software. Results: Each averages of count ratio (Rt / Lt) to have been given at composite image, a blood pool image, delay images analyzed at Raynaud phenomenon patients is $1.25{\pm}0.39$, $1.20{\pm}0.33$, $1.11{\pm}0.17$. The sample analysis results of blood pool image and delay image contented itself with p<0.029. Also, there don't have been each difference, and blood pool image, delay image regarding composite image was able to know. Conclusion: We were able to give help for comparison to evaluate a blood pool image and a local delay image at the Raynaud scan which used $^{201}Tl$ while making a flow image to one sheet image. Identification to be visual too was possible. If you are proceeded a researcher that there was further depth, you are more appropriate for, and you may get useful information.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.28 no.3
• /
• pp.403-411
• /
• 2001

The aim of this study was to evaluate the resistance to degradation of four commercial composite resins in an alkaline solution. The brands studied were Unifil(GC, Japan), Palfique(Tokuyama Japan). Definite$Degussa-H\ddot{u}ls$ AG, Germany). Revolution(Kerr, U.S.A.). Preweighed discs of each brand were exposed 0.1N NaOH solution at $60^{\circ}C$. After 14 days they were removed, neutralized with HCl, washed with water and dried. Resistance to degradation was evaluated on the basis of following parameters: (a) mass loss(%) - determined from pre-and post-exposed specimen weights; (b) Si loss(ppm) - obtained from ICP-AE analysis of solution exposed to specimens; and (c) degradation depth$({\mu}m)$ - measured microscopically (SEM) from polished circular sections of exposed specimens. The results were follows: 1. The mass loss of Unifil was 3.21%, it was the highest of materials. But, there was no significant difference among the materials. 2. The degree of degradation layer depth was $107.69\sim47.40{\mu}m$, the sequence of the degree pf degradation layer depth was in descending order by Unifil, Palfique, Revolution, Definite. There was significant difference among the materials except Palfique and Definite. 3. The Si loss of Paltique was 8940.0ppm, it was the highest. There was significant difference among the materials, except Revolution and Definite(p<0.05). 4. The correlation coefficient between mass loss and degradation depth was relatively high(r = 0.06, p<0.05). 5. There was no significant coefficient correlation between Si loss and mass loss, and/or the degree of degradation layer depth and Si loss. 6. When observed with SEM, destruction of bonding is observed between resin matrix and filler. Above results suggested that the hydrolytic degradation is considered as evaluation factor of composite resins.

• Clinical and Experimental Pediatrics
• /
• v.48 no.2
• /
• pp.197-203
• /
• 2005

Purpose : Changes in metalloproteinases(MMP) activity have been demonstrated in several disease states, including rheumatoid arthritis and tumor metastasis. More importantly, increased myocardial MMP activity has been reported to occur in both clinical and experimental forms of dilated cardiomyopathy. There was no report about MMP in adriamycin(ADR)-induced cardiomyopathy. The purpose of this study was to investigate gene expression of MMP and tissue inhibitor of metalloproteinases(TIMP) in ADR-induced cardiomyopathy and clarify the relationship between MMP and cytokines. Methods : Male Sprague-Dawley rats were divided into two groups. The first group was control. The second group was given intraperitoneal injections of ADR(5 mg/kg) twice a week over two weeks. Serum concentrations of MMP, TIMP, interleukin(IL)-6 and tumor necrosis factor(TNF)-${\alpha}$ were measured. RNA extraction was performed from frozen rat hearts. Reverse transcription polymerase chain reaction(RT-PCR) was employed. cDNA Microarray analysis was performed by using a set of 5,184 sequence-verified rat cDNA clones. Results : Serum MMP and TIMP levels were not significantly different between the two groups. IL-6 was $36.8{\pm}2.8pg/mL$ and TNF-${\alpha}$ $2.2{\pm}2.7pg/mL$ in the ADR group. They were significantly higher than in the control group. Serum MMP correlated significantly with TNF-${\alpha}$(r=0.41, P<0.05). There was no gene expression of MMP, IL-6 or TNF-${\alpha}$ in the hearts of both groups. Gene expression of TIMP was significantly depressed in the hearts of the ADR group. Conclusion : These results suggested a potential role for TNF-${\alpha}$ in the regulation of extracellular matrix remodeling in ADR induced cardiomyopathy. Rapid screening of multiple decreased gene expression by DNA chip may be a useful diagnostic test to detect early cardiac injury before developing ADR induced cardiomyopathy.