• Resources Recycling
• /
• v.5 no.1
• /
• pp.21-28
• /
• 1996

Burmng method tn Bnidi-ied beds 101 the effectlvr reclamation of Sunn fi,uadry sand war u~ed lather tl~an rncchan1c;ll or p~~cumatiace thodq. which are co~nmonlyu scd in foundry factoricr in Kojcu In olrlcr to rcrnuvc hlc;~ns and ha~doersi ~nm foundry sand sndaces in the fluidized bcd, the lnnsl sffccuve lcmpemture mge was h00-70W. Sulbcr slab~l~liyn dca and comliresslvc streugtli oL rccla~mcd sand recyclcd by the burning luctllod wcre lalgcr dao those of rcclalmcd a n d by lllc pncumatlc mctllod. Tile energy cost IOIt he bummy mctliod was cstimalcd al SlZ0011'on oi llie iccl;~~rncds md. The coql l~ductlon in pul.chasing nzw s;od as well as the prevenllon or cnv~conmcnl.il contamlnallnn could hc hmefitcrl hy usl~lg Ihc rec1;~rnnl~oonf liisndry siod ~ecycledb y the method rleieloped in thls sludy

• Journal of the Semiconductor & Display Technology
• /
• v.9 no.2
• /
• pp.33-39
• /
• 2010

The moisture absorption properties such as diffusion coefficient and moisture content ratio of liquid type epoxy resin systems with the filler were investigated. Bisphenol A type and Bisphenol F type epoxy resin, Kayahard MCD as hardener and 2-methylimidazole as catalyst were used in these epoxy resin systems. The nano-sized spherical type fused silica as filler were used in order to study the moisture absorption properties of these liquid type epoxy encapsulant according to the change of filler size. The temperature of glass transition (Tg) of these epoxy resin systems was measured using Dynamic Scanning Calorimeter (DSC), and the moisture absorption properties of these epoxy resin systems according to the change of time were observed at $85^{\circ}C$ and 85% relative humidity condition using a thermo-hygrostat. The diffusion coefficients in these systems were calculated in terms of modified Crank equation based on Ficks' law. An increase of Tg and diffusion coefficient with filler size in these systems can be observed, which are attributed to the increase of free volume with Tg. The change of maximum moisture absorption ratio according to the filler size and filler content cannot be observed; however, the diffusion coefficients of these systems decreased with filler content. The diffusion via free volume is dominant in the epoxy resin systems with low nano-sized filler content; however, the diffusion with the interaction of absorption according the increase of the filler surface area is dominant in the liquid type epoxy encapsulant with high nano-sized filler content.

• Journal of the Korean institute of surface engineering
• /
• v.56 no.2
• /
• pp.152-159
• /
• 2023

The night visibility of pavement is being considered as a global issue in the field of traffic safety. Although the spreading glass beads on the lane paints has been mainly used to secure night-visibility by utilizing the effect of retroreflection, obvious shortcoming of this method is that retroflection does not occur in the range where the headlights do not reach the glass beads. The use of functional paints including phosphorescent constituents could be a solution for overcoming fore-mentioned problem. SrAl₂O₄ based chemicals have not only good phosphorescent property, but also are chemically stable compared to existing ZnS based materials. However, this chemicals also need the improvement due to slightly reduced luminous effect in time. Herein, we developed novel paints showing enhanced phosphorescent properties by putting rare earth elements such as Eu, Dy and Y into SrAl₂O₄. These prepared phosphorescent pigments have displayed improved properties in terms of durability and long afterglow. For instance, the property of afterglow has been persisted after 5 hours with luminace of 20.6 mcd/m².

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.25 no.1
• /
• pp.48-59
• /
• 2023

Ground-level ozone affects human health and plant growth. Ozone is produced by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) from anthropogenic and biogenic sources. In this study, two different land cover and emission factor datasets were input to the MEGAN v2.1 emission model to examine how these parameters contribute to the biogenic emissions and ozone production. Four input sensitivity scenarios (A, B, C and D) were generated from land cover and vegetation emission factors combination. The effects of BVOCs emissions by scenario were also investigated. From air quality modeling result using CAMx, maximum 1 hour ozone concentrations were estimated 62 ppb, 60 ppb, 68 ppb, 65 ppb, 55 ppb for scenarios A, B, C, D and E, respectively. For maximum 8 hour ozone concentration, 57 ppb, 56 ppb, 63 ppb, 60 ppb, and 53 ppb were estimated by scenario. The minimum difference by land cover was up to 25 ppb and by emission factor that was up to 35 ppb. From the modeling performance evaluation using ground ozone measurement over the six regions (East Seoul, West Seoul, Incheon, Namyangju, Wonju, and Daegu), the model performed well in terms of the correlation coefficient (0.6 to 0.82). For the 4 urban regions (East Seoul, West Seoul, Incheon, and Namyangju), ozone simulations were not quite sensitive to the change of BVOC emissions. For rural regions (Wonju and Daegu) , however, BVOC emission affected ozone concentration much more than previously mentioned regions, especially in case of scenario C. This implies the importance of biogenic emissions on ozone production over the sub-urban to rural regions.

• Clinical and Experimental Reproductive Medicine
• /
• v.19 no.1
• /
• pp.31-39
• /
• 1992

By means of the results of In vitro fertilization(IVF) of supernumerary oocytes, the possibility of predicting a pregnancy outcome following gamete intrafallopian transfer(GIFT) and the prognostic implications for future pregnancy were evaluated in 46 GIFT cycles excluding simultaneous program of GIFT and IVF from February, 1989 to July, 1991. IVF of supernumerary oocytes were identified in 21 cycles, but not in remaining 25 cycles. There was no significant difference in age, duration and etiologic factors of infertility, and serum levels of FSH, LH and $E_2$ on MCD #3 and $E_2$ on the day of hCG injection between fertilized(N=21) and unfertilized group(N=25). The number of oocytes retrieved was similar in both groups. The number of supernumerary oocytes available for IVF after transfer was $5.43{pm}2.95$ ranging from 2 to 12. The prenancy rate in fertilized group, 33.3%(7/21), was higher without statistical significance, compared with 8.0%(2/25) in unfertilized group. Using IVF of supernumerary oocytes as a test of pregnancy following GIFT, sensitivity was 77.8 %; specificity, 61.2%; positive predictive value(PPV), 33.3%; negative predictive value(NPV), 92%. The fertilization rate of supernumerary oocytes in pregnant group, $86.4{\pm}22.8%$ was significantly higher compared with $56.1{\pm}20.2%$ in nonpregnant group. In cases with fertilization rate ${\geq}80%$, pregnancy was expected with PPV of 85.7%. In conclusion, IVF of supernumerary oocytes in GIFT program can be a profitable method as a prognostic indicator of pregnancy following GIFT. More aggressive diagnostic and therapeutic measures should be performed in cases with failure in IVF of supernumerary oocytes.

• International Journal of Highway Engineering
• /
• v.13 no.3
• /
• pp.75-82
• /
• 2011

There is the uncertain period of the construction in case of the products meeting the quality standard of KS M 6080, the quality is degraded because of the abrasive loss of the paint caused by vehicle tires as the traffic amount increases and of the loss and detachment of the glass beads providing the retroreflective function. The abrupt degradation of visibility causes the high frequency of traffic accidents at night and increases the traffic accident rate. Additional supplementary construction induces the direct material and construction costs. As the more cost induction effect than the direct cost, the traffic jam caused by the additional construction increases the indirect social costs such as time cost and vehicle cost. Hence, the study is concerned with performing the abrasion resistance test based on the EN 1436 standard to check and improve the quality of various road marking materials resulting in improving the durability of road marking materials. However, even though the difference in the durability lifetime of resins(binders) is bibliographically or theoretically clear, there was no difference in the durability lifetime (retroreflectivity aspect) of the road marking paint using these binders. The reason is that the bonding of beads was very insufficient or that the cross density caused by crack or freshness was low. Moreover, the measured wet retroreflectivity was distributed as the Rw3 or higher class in average on the basis of EN 1436 but was very insufficient on the basis of the minimum wet threshold retroreflectivity with 100mcd/($m^2{\cdot}lx$) managed overseas.

• Journal of The Korean Association For Science Education
• /
• v.30 no.8
• /
• pp.933-952
• /
• 2010

This study aims to characterize debate on a socio-scientific issue in the Internet and to provide implications from a postmodernist perspective. This study concentrates on disentanglement of the complex relationship among society, economy, politics and science in an issue and characterization of the given text centering on its originality, the relationship between writer and reader, and the purpose of utterance. Sixty-six most read articles on a web message board were chosen and analyzed as a typical case of a socio-scientific issue in the internet. In them, five scientific disputes were identified: the cause of mad cow disease (MCD), specified risk material and the incubation period, the cause of new variant Creutzfeld-Jakob disease (vCJD), vulnerability of vCJD and the relation of Alzheimer and vCJD in American patients. Each argument is intertwined with social, economic and political problems such as its impact on the domestic beef market, feeding environment of imported cattle and the retaliation against denial of importation. With regard to originality, it is found that the originality of an author is weakened but communal through repetitive quotation of 'Peom', cutting and pasting, and engagement of readers with their comments. Furthermore, in order to close the gap between writer and reader, identity and personal narrative of the writers are often introduced into their writing. In terms of purpose of utterance, these are intended to deliver one's feelings or facilitate human behavior rather than inform through verification of a principle.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.12
• /
• pp.4912-4933
• /
• 2015

Information Centric Networking (ICN) has recently attracted great attention. It names the content decoupling from the location and introduces network caching, making the content to be cached anywhere within the network. The benefits of such design are obvious, however, many challenges still need to be solved. Among them, the local caching policy is widely discussed and it can be further divided into two parts, namely the cache permission policy and the cache replacement policy. The former is used to decide whether an incoming content should be cached while the latter is used to evict a cached content if required. The Internet is a user-oriented network and popular contents always have much more requests than unpopular ones. Caching such popular contents closer to the user's location can improve the network performance, and consequently, the local caching policy is required to identify popular contents. However, considering the line speed requirement of ICN routers, the local caching policy whose complexity is larger than O(1) cannot be applied. In terms of the replacement policy, Least Recently Used (LRU) is selected as the default one for ICN because of its low complexity, although its ability to identify the popular content is poor. Hence, the identification of popular contents should be completed by the cache permission policy. In this paper, a cache permission policy called Cache-Filter, whose complexity is O(1), is proposed, aiming to store popular contents closer to users. Cache-Filter takes the content popularity into account and achieves the goal through the collaboration of on-path nodes. Extensive simulations are conducted to evaluate the performance of Cache-Filter. Leave Copy Down (LCD), Move Copy Down (MCD), Betw, ProbCache, ProbCache⁺, Prob(p) and Probabilistic Caching with Secondary List (PCSL) are also implemented for comparison. The results show that Cache-Filter performs well. For example, in terms of the distance to access to contents, compared with Leave Copy Everywhere (LCE) used by Named Data Networking (NDN) as the permission policy, Cache-Filter saves over 17% number of hops.

• Korean Journal of Remote Sensing
• /
• v.31 no.2
• /
• pp.51-64
• /
• 2015

We improved the MODerate resolution Imaging Spectroradiometer (MODIS) land cover map over the Asia-Oceania region through the reclassification of the misclassified pixels. The misclassified pixels are defined where the number of land cover types are greater than 3 from the 12 years of MODIS land cover map. The ratio of misclassified pixels in this region amounts to 17.53%. The MODIS Normalized Difference Vegetation Index (NDVI) time series over the correctly classified pixels showed that continuous variation with time without noises. However, there are so many unreasonable fluctuations in the NDVI time series for the misclassified pixels. To improve the quality of input data for the reclassification, we corrected the MODIS NDVI using Correction based on Spatial and Temporal Continuity (CSaTC) developed by Cho and Suh (2013). Iterative Self-Organizing Data Analysis (ISODATA) was used for the clustering of NDVI data over the misclassified pixels and land cover types was determined based on the seasonal variation pattern of NDVI. The final land cover map was generated through the merging of correctly classified MODIS land cover map and reclassified land cover map. The validation results using the 138 ground truth data showed that the overall accuracy of classification is improved from 68% of original MODIS land cover map to 74% of reclassified land cover map.

• Journal of Nutrition and Health
• /
• v.56 no.2
• /
• pp.123-139
• /
• 2023

Purpose: This study was conducted to establish whether an ethanol extract of Lycium barbarum leaves (LLE) and an ethanol extract of Lycium barbarum leaves from which chlorophyll has been removed, denoted as LLE(Ch^-), have a protective effect against hepatic fat accumulation. Methods: The inhibitory effects of LLE and LLE(Ch^-) on liver fat accumulation were examined in C57BL/6 mice with non-alcoholic fatty liver disease (NAFLD) induced by an methionine and choline deficient diet and in HepG2 cells with palmitic acid-induced fat accumulation. Results: The plasma triglyceride, aspartate aminotransferase, and alanine aminotransferase levels were lower in the LLE(Ch^-) group, whereas the plasma ALT activity decreased significantly in the LLE group. In both the LLE and the LLE(Ch^-) groups, the triglyceride and cholesterol contents in the hepatic tissue were significantly reduced. A greater inhibitory effect on tissue fat accumulation was observed in the LLE(Ch^-) group than in the LLE group. In HepG2 cells, LLE and LLE(Ch^-) were non-toxic up to a concentration of 1,000 ㎍/mL. Compared to the control group, intracellular fat accumulation in the LLE and LLE(Ch^-) groups were significantly reduced at concentrations of 200 ㎍/mL and 500 ㎍/mL, respectively. The expression of phosphorylated adenosine monophosphate-activated protein kinase and phosphorylated acetyl-CoA carboxylase in both LLE groups increased at the concentrations of 100 ㎍/mL and 500 ㎍/mL. The fatty acid synthase expression was suppressed in a concentration-dependent manner at 10 ㎍/mL. Conclusion: The examined two ethanol extracts of LLE inhibit hepatic fat accumulation in NAFLD. This effect was more pronounced in the LLE(Ch^-) group. Therefore, these 2 extracts have an anti-steatosis effect and can be used for NAFLD treatment.