• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.1201-1206
• /
• 2004

This paper deals with the numerical analysis of natural convection flow induced by the density inversion effect of water inside horizontal pipe. The numerical method is based on SIMPLE/PWIM in general coordinate for its wide applicabilities. The numerical tool was validated through the comparison with the previous results concerning the density inversion effect of water It is shown that the developed numerical tool could predict the flow pattern and the heat transfer phenomena qualitatively And it is also found that the density inversion effect of water has significant effects on the flow pattern.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
• /
• pp.313-316
• /
• 2004

In this paper, it was assessed durability of ultra-high strength cementitious composites(UHSCC) with the range of 180MPa of compressive strength through the test method of chloride ion resistance, carbonation, freezing-thawing resistance, permeability. In order to compare with ultra-high strength cementitious composites, normal concrete and high-strength concrete were also tested. As the experimental result, it showed that UHSCC was cleary superior to the durability performance of normal concrete and high-strength concrete.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1996년도 추계학술대회
• /
• pp.281-285
• /
• 1996

Pulsatile swelling behaviors and their application to drug delivery system were studied by using interpenetrating polymer networks(IPN) hydrogels constructed with poly(vinyl alcohol) and poly(acrylic acid). The PVA/PAAc IPNs hydrogels were symthesized by UV irradiation tallowed by repetitive freezing and thawing method. These hydrogels showed pH and temperature sensitive swelling behaviors. From the release experiment, the release amount of model drug incorporated into these hydrogels showed pulsatile patterns. Permeability coefficients obtained by various solutes differed in response to changes of permeation conditions.

• 한국산업융합학회 논문집
• /
• 제9권2호
• /
• pp.147-154
• /
• 2006

The authors conducted field experiments of frost heave to evaluate a method for reducing frost susceptibility using granulated used-tire mixture for 3 winters. Qualitative analyses for the evaluation of restraint effect of frost susceptibility by utilizing granulated used-tire soil mixture were conducted with the segregation potential concept and frost heave ratio. By mixing soil with granulated tire, the frost susceptibility was decreased drastically. From the result of the analyses, it was confirmed that granulated tire is an excellent material in controlling the frost susceptibility.

• 한국멀티미디어학회논문지
• /
• 제22권10호
• /
• pp.1133-1141
• /
• 2019

Most of the previous studies for bark recognition have focused on the extraction of LBP-like statistical features. Deep learning approach was not well studied because of the difficulty of acquiring large volume of bark image dataset. To overcome the bark dataset problem, this study utilizes the MobileNet which was trained with the ImageNet dataset. This study proposes two approaches. One is to extract features by the pixel-wise convolution and classify the features with SVM. The other is to tune the weights of the MobileNet by flexibly freezing layers. The experimental results with two public bark datasets, BarkTex and Trunk12, show that the proposed methods are effective in bark recognition. Especially the results of the flexible tunning method outperform state-of-the-art methods. In addition, it can be applied to mobile devices because the MobileNet is compact compared to other deep learning models.

• 한국해양생명과학회지
• /
• 제1권1호
• /
• pp.70-78
• /
• 2016

Microalgae are of significant importance for future biotechnological applications. Many microalgae banks or laboratories attempt to maintain various microalgae for further research purposes. Cryopreservation has been preferred to reduce a labor-intensive and costly routine sub-culturing. Cryopreservation can also diminish the genetic drift risk. However, cryopreservation as a long term storage of microalgae method are still in developing progress because it cannot be generalized for all microalgae. Microalgae types, cryoprotectant agents (CPAs) types, freezing and thawing methods are the most important factors that should be considered for cryopreservation. In this short review the basic principles and the current advanced of microalgae cryopreservation methods are discussed with a suggested starting parameters for microalgae cryopreservation.

• 한국수정란이식학회지
• /
• 제27권4호
• /
• pp.259-264
• /
• 2012

Solution of glycerol, ethylene glycol, sucrose, dextrose (GESD) and cryotop methods were carried out to investigate the survivability on vitrification of embryos. Embryos cultured in vitro were vitrified by GESD of 10 or 8 step and cryotop methods of 6 step, from cryopreservation step to frozen-thawed and culture step. Survival rate and ICM, TE cells of embryos were investigated after frozen-thawed 24 h. As a results, cryotop method was significantly (p<0.05) higher ($85.76{\pm}5.3$ vs. $66.71{\pm}2.4$, $44.80{\pm}2.1%$) than GESD 10 or 8 step methods on survivability. Also, In ICM cell number, cryotop method was significantly (p<0.05) higher to $45.67{\pm}4.7$ cells than GESD 8 step method. TE cell number was significantly (p<0.05) highest to $111.00{\pm}11.0$ cells in cryotop method. On the other hand, survival rate, TE and total cell number were all the significantly (p<0.05) high, except ICM in GESD 10 step method between GESD 10 step method and GESD 8 step method. In conclusion cryotop method was to be most effective, but it is considered necessary to study vitrification method for step-by-step freezing and thawing process.

• 한국가금학회지
• /
• 제23권4호
• /
• pp.193-201
• /
• 1996

This experiment was carried out to find out the effect of packing methods on physico-chemical properties of breast and thigh meats in chicken, which was dried by air spray chilling method. The chicken carcass was cut into breast and thigh muscles, which were either vacuum packed or atmosphere packed, and stored at -2O˚C for 1, 4, 8, 12 and 16 wk after quick freezing at -45˚C for 35 min. The pH values of atmosphere-packed breast meat and vacuum-packed breast meat after one wk of storage were higher than those of atmosphere-packed thigh meat and vacuum-packed thigh meat(P< .05). The pH values increased as storage period extended, but no significant difference was detected between two packing method(vacuum vs. atmosphere). Total moisture contents of breast meats after one wk of storage were higher than those of thigh meats. The total moisture contents decreased slowly as storage period extended, but no significant difference was detected between two packing method(vacuum vs. atmosphere). The shear force value of thigh meat was higher than that of breast meat. The shear force values of both meats decreased as storage period extended, regardless of packing method. The water soluble protein extractability of thigh meats was higher than that of breast meat, and the water soluble protein extractability of all treatments decreased until 8 wk after storage, but increased gradually after 8 wk of storage period. The salt soluble protein extractability of breast meat was higher than that of thigh meat, and the salt soluble protein extractability of all treatments decreased as storage period extended. With regard to the packing method, the vacuum packing showed higher value than that of atmosphere packing method until 8 wk of storage. Total lipid contents of atmosphere- and vacuum-packed thigh meats at 1 wk of storage were higher than those of breast meats, and the total lipid contents of all of treatments decreased as storage period extended. However, no significant difference was detected between two packing methods. The fatty acid contents of breast and thigh meats were in order of o1eic(33,5~42.4), palmitic(19.7~30.8) and linoleic acid(10.8~17.4).

• Reproductive and Developmental Biology
• /
• 제38권1호
• /
• pp.1-8
• /
• 2014

Artificial insemination technique has been contributed immensely for production of livestock worldwide as a critical assisted reproductive technique to preserve and propagate excellent genes in domestic animal industry. In the past decade, methods for semen preservation have been improved mostly in liquid preservation method for boar semen and freezing method for bull semen. Among many factors affecting semen quality during preservation, reactive oxygen species, produced by aerobic respiration in sperm for survival and motility, are unfavorable to sperm physiology. In mammalian cell as well as in the sperm, antioxidant system plays a role in degradation of reactive oxygen species. Magnetized water forms smaller stabilizing water clusters, resulting in high absorption and permeability of the cell for water, implicating its application for semen preservation. Therefore, this review focuses on preservation methods of boar and bull semen with respect to improvement of extender and reduction of reactive oxygen species by using magnetized water and supplementation of antioxidants.

• 한국수정란이식학회지
• /
• 제12권2호
• /
• pp.151-159
• /
• 1997

In vitro fertilization(IVF) derived morula and blastocyst embryos were bisected by a simple method and cultured in vitro without zona pellucida And also bisected embryos were frozen-thawed and cultured in vitro) to evaluate the survival rate. The results obtained were as follows : The average number of grade I or II immature follicular oocytes recovered by slicing method per ovary was 11.9 from 142 ovaries. Following in vitro fertilization, the rates of cleavage and in vitro development to morula and blatocyst were 61.7 and 32.2% respectively. The successful bisection rate of IVE embryos was 67.51%, and the embryos of blastocyst stage were bisected successfully at significantly(P