• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.12
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• pp.660-667
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• 2013

This study presents a numerical investigation of the heat and mass transfer kinetics of a fin-tube-type adsorption bed using a two-dimensional numerical model with silica-gel and water as the adsorbent and refrigerant pair. The performance is strongly affected by the heat and mass transfer in the adsorption bed, but the details of the mass transfer kinetics remain unclear. The validity of inter-particle models used to simulate mass-transfer kinetics were examined, such as a constant pressure model and non-constant pressure model, and the valid ranges of the diffusion ratio for each model are proposed. The COP and SCP have been numerically calculated as the performance indexes according to the diffusion ratio. The constant pressure model, which is commonly used in previous research, was found to be valid only in a limited range of diffusion ratio.

• Korean Journal of Microbiology
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• v.29 no.1
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• pp.8-15
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• 1991

Interspecific hybrids between the ASpergillus spp., A. awamori, A. usamii and A. oryzae, were obtained by nuclear transfer technique. Nuclei isolated from an auxotrophic mutant strain were transferred into the protoplasts of a recipient strain of different species. The frequency of interspecific hybrid formation by nuclear transfer was $2*10^{-5}$ $-7*10^{-4}$ In contrast, no interspecific hybrid was isolated by protoplast fusion. Among the hybrids tested, 10 strains showed increased activity of some or all components of cellulases, xylanases and amylase up to more than two times. Isozyme pattern of the hybrids were analyzed by polyacrylamide gel electrophoresis and isoelectric focusing followed by activity staining, which showed that some of the hybrids have isozyme patterns unidentical to either of the two parents. By measuring the DNA contents and the sizes ofthe conidia, the karyotypes of the hybrids were estimated to be aneuploid near to haploid, diploid or triploid. It was concluded that the unclear transfer technique is much more efficient in the formation of interspecific hybrids than protoplast fusion and is very useful for the improvement of Aspergillus strains.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.478-484
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• 2017

This study analyzed statistically the determinants that affect the royalties of knowledge technology transfer, which accounts for a considerable portion of university technology transfer. As knowledge technology transfer certainly includes a move from tacit knowledge from one side to the other side per se, the scope of knowledge technology transfer is unclear and numerical information of technology transfer, such as research fund scale, which is used widely in previous studies, cannot be used in the analysis. Therefore, this study focused on the researcher characteristics and included its explanatory variables in the present study. In addition, it included the technical characteristics of the knowledge transferred and the characteristics of the contracting company. The knowledge maturity calculated from the appointment year and contract date positively affects the technology royalties, but work experience and patent activity of the researcher are not statistically significant. Statistically significant differences in the technology royalty according to the type of technology transfer and the company location were observed, but there was no meaningful change in the technology royalty depending on the technical field and company business scale.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2005.10a
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• pp.128-128
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• 2005

• Proceedings of the KSAR Conference
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• 2002.06a
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• pp.39-39
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• 2002

The mechanisms underlying the visual assessment and resulting in optimum embryonic development following in vitro maturation, fertilization, and culture are unclear. It is known that in vitro produced embryos show more frequent occurrence of fragmentation, which result in poor developmental potential and decreased implantation rate. The objective of this study was to investigate the apoptotic rates in in vitro fertilization (IVF) and nuclear transferred (NT)bovine blastocyst. (omitted)

• Journal of Embryo Transfer
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• v.33 no.1
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• pp.49-54
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• 2018

Adenomyosis is a benign gynecological disease frequently affecting women of reproductive age. It has a negative impact on the quality of life, causing bleeding disorders, dysmenorrhea, chronic pelvic pain, and infertility. However, the molecular mechanisms involved in adenomyosis development remain unclear. This paper summarizes the reports found in the MEDLINE database on the molecular mechanisms involved in the development and progression of uterine adenomyosis. The literature search included the following terms: "adenomyosis," "adenomyoma," "pathogenesis," "molecular mechanisms," and "gynecological disorders." Only peer-reviewed, English-language journal articles were included. This review focuses on the molecular genetics, epigenetic modifications, and pivotal signaling pathways associated with adenomyosis development and progression, which will provide insights into and a better understanding of its underlying pathophysiology.

• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.398-406
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• 2015

In this study, R-123 flow boiling experiments were carried out to investigate the effects of nanoparticle deposition on heater surfaces on flow critical heat flux (CHF) and boiling heat transfer. It is known that CHF enhancement by nanoparticles results from porous structures that are very similar to layers of Chalk River unidentified deposit formed on nuclear fuel rod surfaces during the reactor operation period. Although previous studies have investigated the surface effects through surface modifications, most studies are limited to pool boiling conditions, and therefore, the effects of porous surfaces on flow boiling heat transfer are still unclear. In addition, there have been only few reports on suppression of wetting for decoupled approaches of reasoning. In this study, bare and $Al_2O_3$ nanoparticle-coated surfaces were prepared for the study experiments. The CHF of each surface was measured with different mass fluxes of $1,600kg/m^2s$, $1,800kg/m^2s$, $2,100kg/m^2s$, $2,400kg/m^2s$, and $2,600kg/m^2s$. The nanoparticle-coated tube showed CHF enhancement up to 17% at a mass flux of $2,400kg/m^2s$ compared with the bare tube. The factors for CHF enhancement are related to the enhanced rewetting process derived from capillary action through porous structures built-up by nanoparticles while suppressing relative wettability effects between two sample surfaces as a highly wettable R-123 refrigerant was used as a working fluid.

• Journal of Sensor Science and Technology
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• v.26 no.3
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• pp.214-222
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• 2017

In this study, the effects of internal heat treatment associated sintering temperatures were simulated by the Finite Element Method (FEM). The sintering mechanism of pulsed current activated sintering process (PCAS) is still unclear because of some unexplainable heat transfer phenomena in coupled multi-physical fields, as well as the difficulty in measuring the interior temperatures of metal powder. We have carried out simulation study to find out thermal distributions between graphite mold and Ruthenium powder prior to PCAS process. For PCAS process, heating rate was maintained at $100^{\circ}C/min$ the simulation indicates that the sintering temperature range was between $1000^{\circ}C$ to $1300^{\circ}C$ under 60 MPa. The heat transfer inside the Ruthenium sintered-body sample was modelled through the whole process in order to predict the minimum interior temperature. Thermal simulation shows that the interior temperature gradient decreased by graphite punch length and calculation results well agreed with the PCAS field test results.

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.273-279
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• 2010

Follicular cystic follicles (FCFs) show delayed regression with persistent follicle growth. However, the mechanism by which follicles are persistently grown remains unclear. Glutathione S-transferases (GSTs) are drug-metabolizing and detoxification enzymes that are involved in the intracellular transport and metabolism of steroid hormones. In this study, a proteomic analysis was performed to identify whether GST expression is changed in bovine FCFs and to predict the interactions between GST and other proteins. Normal follicles and FCFs were classified based on their sizes (5 to 10 mm and 25 mm). In bovine follicles, GST mu 1 (GSTM1) was detected as a differentially expressed protein (DEP) and significantly up-regulated in FCFs compared to normal follicles (p<0.05). Consistent with the proteomic results, semi-quantitative PCR data and western blot analysis revealed an up-regulation of GSTM1 in FCFs. Expression levels of aromatase and dehydrogenase proteins were changed in FCFs. These results show that the up-regulation of GSTM1 that is observed in bovine FCFs is likely to be responsible for the persistent follicle growth in FCFs as the activity of aromatase and the dehydrogenases.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.5
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• pp.60-65
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• 2019

Since nanofluids (NFs), which are a mixture of a small amount of nanoparticles and a bulk liquid solvent, were first proposed by Stephen Choi at the Argonne National Lab in 1995, they have been considered for use in many technical studies of power cooling systems and their practical application due to their high thermal conductivity and heat transfer coefficients compared to conventional coolants. Although nanofluids are a well-known form of engineering fluid that show great promise for use in future cooling systems, their underlying physics as demonstrated in experiments remain unclear. One proven method of determining the heat transfer performance of nanofluids is measuring the concentration of nanoparticles in a mixture. However, it is experimentally inefficient to build testbeds to systematically observe particle distributions on a nanoscale. In this paper, we demonstrate the distribution of nanoparticles under a temperature gradient in a solution using molecular dynamics simulations. First, temperature profiles based on substrate temperature are introduced. Following this, the radial pair distribution functions of pairs of nanoparticles, solvents, and substrates are calculated. Finally, the distribution of nanoparticles in different heating regions is determined.