• Asian-Australasian Journal of Animal Sciences
• /
• v.11 no.6
• /
• pp.655-660
• /
• 1998

To produce blastocysts more efficiently, it is required to identity accurately the factors involving embryonic cleavage in the chemically defined medium. Effects of pyruvate, lactate, calcium and protein sources on early cleavage of bovine follicular oocytes were investigated. The percentage of IVF embryos cleaved to ${\geq}$ 2-cell or ${\geq}$ 8-cell was higher in pyruvate (+) and lactate (+) (48 or 14%) than in pyruvate (-) and lactate (-) (22% or 4%), than in pyruvate (+) and lactate (-) (28% or 5%) and than in pyruvate (-) and lactate (+) (40% or 10%). Lactate was more effective than pyruvate during early cleavage of bovine embryos in the chemically defined medium. The percentage of IVF embryo cleaved to ${\geq}$ 2-cell and ${\geq}$ 8-cell in calcium (-) (19 and 6%) was significantly (p < 0.05) lower than in calcium (+) (78 and 45%). The percentage of embryos developed to ${\geq}$ 2-cell showed no significant (p < 0.05) difference among BSA, 1 and 20% FBS (57, 57 and 57%). Also the percentage of A grade embryos developed to ${\geq}$ 2-cell showed no significant (p < 0.05) difference among BSA, 1 and 20% FBS (40, 35 and 28%). The percentage of embryos developed to ${\geq}$ 8-cell showed no significant (p < 0.05) difference among BSA, 1 and 20% FBS (33, 23, and 22%). However, the percentage of A grade embryos developed to ${\geq}$ 8-cell in BSA (24%) was significantly (p < 0.05) higher than in 1 and 20% FBS (13 and 8%). The percentage of embryos developed to ${\geq}$ morula showed no significant (p < 0.05) difference among BSA, 1, 10 and 20% FBS (76, 76, 80 and 68%). The percentage of A grade embryos developed to ${\geq}$ morula in 10% FBS (59%) was significantly (p < 0.05) higher than 20% FBS (43%). The percentage of embryos developed to blastocyst showed no significant (p < 0.05) difference among BSA, 1, 10 and 20% FBS (34, 41, 43 and 32%). However, the percentage of A grade embryos developed to ${\geq}$ blastocysts in 10% FBS (25%) was significantly (p < 0.05) higher than in 20% FBS (8%).

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.18 no.6
• /
• pp.167-177
• /
• 2015

This study was conducted to establish an inventory and propose conservation strategies for 'village wetlands' in Asan city, Korea, using GIS. As results, the village wetlands are defined as such places as 'palustrine' wetland, village embankment, agricultural reservoir or small reservoirs located in or near the village and related to everyday life or farming. Firstly 807 provisional village wetlands(draft) were identified in Asan by using Arc-GIS 10.1, then 196 wetlands(final) were defined finally as village wetlands and listed the inventory of Asan Village Wetlands after being validated through office works and field survey. The office works analyzed minimum area(greater than $625m^2$), satellite images, the Korea Land Information System, land use map and land coverage map. To evaluate the function and conservation values, the 37 wetlands were selected for detailed surveying and function assessment based on the following criteria : 1) doubled code both wetland and reservoir at digital map, 2) located less than 100m from village and 3) ecologically connected to such ecological resources as seaside mudflats, mountains and green area and ecological passages for small size wildlifes. As the result of the wetland function assessments by the RAM method, 7 wetlands were found to have 'high' wetland function (conservation) 18 wetlands were 'medium' (enhancement) and 12 wetlands were 'low' (restoration or enhancement). Enhancing biodiversity and ecosystem services through ecological management of wetlands in Asan and connecting with the Ecological Natural Degree were proposed.

• Journal of Embryo Transfer
• /
• v.14 no.1
• /
• pp.31-37
• /
• 1999

The objective of this study was to optimize the selection of sperm sources, optimal culture systems and vitrification method depends on sperm sources. The oocytes were inseminated with either KPN 105, 114, 191, SNU 101, 102, 103 or epididymis and then embryos inseminated were cultured in oviductal cell co-culture or HECM-6 as defined me dium. The blastocysts produced were pooled according to sperm sources as KPN, SNU or epididymis and then vitrified by OPP vitrification method. The results obtained were as follows: 1. The cleavage(86.2 or 84.7%) and development rates to blastocyst (30.6 or 32.0%) were not significantly different between oviductal cell co-culture or HECM-6 culture systems(P<0.05). 2. To determine the optimal sperm sources for using IVF in this system, cleavage rates in KPN 191 and SNU 101 (74.2, 55.8%) were significantly lower rather than those in KPN 105, 114, SNU 102, 103 or epididymis (86.7, 85.1, 89.8, 85.5 or 81.2%), but development rates to blastocyst in KPN 114, SNU 103 or epididymis sperm (30.0, 33.0 or 28.6%) were significantly higher rater than those in KPN 105, 191, SNU 101, 102(21.4, 15.4, 14.9 or 25.4%), respectively (P<0.05). 3. The blastocysts produced were pooled according to sperm sources as KPN, SNU or epididymis and then vitrified by OPP vitrification method. The survival rates were not significantly different among sperm sources (89.6%: 43/48 ; 90.1%: 46/51 ; 83.3% : 20/24). These results obtained indicate that the defined medium, HECM-6, could be use to produce of IVP bovine embryos. Since the frozen semen must be required to maintain of unvariation data in IVP embryo production system, KPN 114 and SNU 103 produced in our laboratory were useful for this purpose. The blastocysts produced by different sperm sources as KPN, SNU or epididymis were vitrified by OPP vitrification method and survived very high rates. The OPP vitrification method could be susceptibility to use of IVP bovine blastocyst embryos.

• Journal of Korean Elementary Science Education
• /
• v.35 no.4
• /
• pp.389-405
• /
• 2016

The purpose of this study was to analyze elementary school teachers' understanding, certainty, and familiarity with 13 key concepts of wave physics that are presented in textbook and teacher's guidebook. 123 elementary school teachers answered concept tests and questionnaires. In the results to these tests and questionnaires, teachers demonstrated a high level of understanding and high certainty in understanding with regard to the concepts of sound generation, effect of medium on wave, timbre, wavelength, and trough and crest of wave. For the topics of sound velocity, wave reflection and wave transmission, teachers demonstrated a high level of understanding but low certainty in understanding. With regard to sound propagation, teachers demonstrated a low level of understanding and an improperly high certainty in that low understanding. Teachers lacked knowledge, i.e., displayed a low level of understanding and low certainty in sound strength, sound frequency, constructive interference and destructive interference. In constructive and destructive interference, the teachers also displayed a low level of familiarity. We analyzed the differences in teacher's understanding, certainty, and familiarity according to teacher demographics defined by the teacher's gender, teaching experience with concepts of sound, career, curriculum track while in high school, and major in university. There were no significant differences in understanding, certainty, or familiarity as defined by gender, teaching experience, and career. However, these displays of knowledge were affected by the teacher's curriculum track in high school and their major. These results suggest that the teacher's understanding of, familiarity with, and certainty in wave physics concepts are more influenced by their learning experience than by their teaching experience. Therefore, we suggest additional learning opportunities for teachers (such as teacher training programs) in order to improve teacher knowledge and correct teacher misconceptions in wave physics.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1997.10a
• /
• pp.69-70
• /
• 1997

Polyimides and related polymers, when synthesized from aromatic monomers, have generally rigid chain structures resulting in a low gas permeability. The rigidity of polymer chains reduces the segmental motion of chains and works as a good barrier against gas transport. To overcome the limit of use as materials of gas separation membranes due to low gas permeability, block copolymers with the incorporation of flexible segments like siloxane linkage and ether linkage have been studied. These block copolymers have microphase-separated structures composed of microdomains of flexible poly(dimethylsiloxane) or polyether segments and of rigid polyimides segments. In case of rigid-flexible block copolymers, the characteristics of both phases for gas permeation are of great difference. The permeation of gas molecules occurs favorably through microdomains of flexible segments, whereas those of rigid segments hinder the permeation of gas molecules. Accordingly the increase of content of flexible segments in a rigid polymer matrix will increase the gas permeability of the membrane linearly. However, this prediction does not satisfy enough many experimental results and in particular the drastic increase of the permeability is observed in a certain volume fraction. It was proposed that the gas transport mechanism is dominated by diffusion rather than gas solubility in a certain content of flexible phase if solution-diffusion mechanism is adopted. However, the transition from solubility-dependent to diffusion-dependent cannot be explained by the understanding of mechanism itself. Therefore, we consider an effective chemical path which permeable phase can form in a microheterogenous medium, and percolation concept is introduced to describe the permeability transition at near threshold where for the first time a percolation path occurs. The volume fraction of both phases is defined as V$_{\alpha}$ and V$_{\beta}$ in block copolymers, and the volume of $\beta$ phase in the threshold forming geometrically a traversing channel is defined as V$_{\betac}$. The formation mechanism of shortest chemical channel is schematically depicted in Fig. 1.

• The Korean Journal of Ecology
• /
• v.27 no.2
• /
• pp.79-86
• /
• 2004

An extensive study of the vegetation characteristics of the Hamersley Ranges, a mountainous desert area of north-west Australia, facilitated the comparison of plant species diversity measures with mountainous deserts of other parts of the world. Alpha diversity was defined as the number of species co-existing at local scales and was found to average 18 species per 0.1 ha for the Hamersley Ranges. This was found to be similar to seven other mountainous deserts in North and South America, and southern Africa. Variation in alpha diversity between these deserts was found to considerably lower than within deserts, suggesting that local processes control species richness at local scales. Beta diversity, defined here as turnover in species composition at various spatial scales, can be measured in many ways. For the Hamersley Ranges, Wilson's β ranged from 1.2 to 1.6 for five sites along a topographic gradient, whereas Whittaker's β between different plant communities was found to average 0.93. Comparable data was not found for other desert areas, but comparisons to non-desert areas suggest beta diversity within landscapes is relatively high and is likely to reflect the considerable landform heterogeneity of the Hamersley Ranges. 55∼70% of species were shared between different landscapes of the Hamersley Ranges; comparisons to other regions suggest beta diversity at this scale is relatively low. Gamma diversity, the number of species over large spatial extents, was successfully compared using regression analysis of the log-log species - area relationship. This revealed that the northern Sonoran desert has significantly less species than the Nama (inland) Karoo and Hamersley Ranges over medium spatial extents, but species numbers were similar at a regional scale. Several constraints to the valid comparison of species diversity were identified, including lack of standardisation of sampling techniques, the wide range of measures employed, general lack of published data, and the influence of the various components of spatial scale on most diversity measures. Recommendations on how to improve future comparative work are provided.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.4
• /
• pp.107-118
• /
• 2010

The user interface is the medium, which provides the users to have an access to the web-based information system. The user interface is the means of improving usability and accessibility for the user, as well as being the core component in the web-based information system. In this paper, the audit framework of the user interface was developed to upgrade the usability and accessibility; it was based on the three basic components of the current audit framework in the web-based information system. At the time of an audit, the UI process of the 'Analysis', 'UI Design', 'UI Production', and 'Test' was defined, which was analyzed through the web development methodology. Also, for the area of an audit, the 'Information', 'Design', and 'Technology' were defined by the analysis of the components that makes up the user interface, From the view of an audit, the standard criteria of an assessment were set as 'Usability', 'Accessibility', and 'Cross Browsing'. Through the framework that was proposed in this paper, practical audit applies the performed examples. By this, the efficiency of the proposed framework was verified.

• Journal of the Korean Chemical Society
• /
• v.6 no.1
• /
• pp.10-13
• /
• 1962

Titanium in solution of EDTA (Ethylenediaminetetraacetic acid) yield well-defined, reversible polarographic waves. In this report, a polarographic method for rapid determination of titanium in the Korean ilmenite was proposed, This polarographic method is based on the measurement of polarogram in the supporting electrolyte of EDTA. As the pH is increased the wave become more irreversible the diffusion current are diminished, and the half wave potential become more negative. In spite of the complication arising from numerous titanium species, in 0.2 M of EDTA, pH 6.3, the titanium waves are reproducible and analytically useful. In this medium titanium ion give well-defined reduction wave, and the half wave potential were -0.61V vs S.C.E. at pH 6.3. At the same time, the wave had a linear relationship between the concentration of titanium ion and the wave height. The Korean ilmenites were analyzed by this method and satisfactory results were obtained.

• Nuclear Engineering and Technology
• /
• v.49 no.3
• /
• pp.549-555
• /
• 2017

A lead slowing-down spectrometer (LSDS) system is under development to analyze isotopic fissile content that is applicable to spent fuel and recycled material. The source neutron mechanism for efficient and effective generation was also determined. The source neutron interacts with a lead medium and produces continuous neutron energy, and this energy generates dominant fission at each fissile, below the unresolved resonance region. From the relationship between the induced fissile fission and the fast fission neutron detection, a mathematical assay model for an isotopic fissile material was set up. The assay model can be expanded for all fissile materials. The correction factor for self-shielding was defined in the fuel assay area. The corrected fission signature provides well-defined fission properties with an increase in the fissile content. The assay procedure was also established. The assay energy range is very important to take into account the prominent fission structure of each fissile material. Fission detection occurred according to the change of the Pu239 weight percent (wt%), but the content of U235 and Pu241 was fixed at 1 wt%. The assay result was obtained with 2~3% uncertainty for Pu239, depending on the amount of Pu239 in the fuel. The results show that LSDS is a very powerful technique to assay the isotopic fissile content in spent fuel and recycled materials for the reuse of fissile materials. Additionally, a LSDS is applicable during the optimum design of spent fuel storage facilities and their management. The isotopic fissile content assay will increase the transparency and credibility of spent fuel storage.

• Information Systems Review
• /
• v.7 no.2
• /
• pp.195-211
• /
• 2005

The purpose of this case study is to suggest the indicators of an informatization maturity level and critical success factors in small and medium automotive parts manufacturers. To achieve this goal, literature reviews and case studies on 7 automotive parts manufacturers that confirmed to implement information systems successfully, were conducted. Based on literature review, the six functional processes including development, production scheduling, purchase, production, order, and support process, were defined. Each process has 5 levels from 1(low level) to 5(high level) depending on the degree of informatization maturity. In addition, critical success factors were discovered with interviews of CEO or CIO. The results of this study can be applied to any companies which are implementing or intended to the information systems near future.