• The Journal of Engineering Geology
• /
• v.25 no.4
• /
• pp.499-510
• /
• 2015

Artificial accelerated weathering test evaluated rocks from near the circuit road of Ulleungdo island, approximately 120 km from east of the Korean Peninsula. The tests subjected rock specimens to conditions based on the climate of the island. The specimens (such as basaltic breccia, trachyte, volcanic breccia) were preliminarily classified using a TAS diagram (XRF data) and based on the constituent minerals (XRD data); they were further classified by weathering degree according to their absorption ratios. During the artificial accelerated weathering, the absorption ratio of most of the specimens increased, but the point-load strength did not decrease in most cases, except for the volcanic breccia. The greater initial absorption ratio of trachyte rock specimen in comparison with the other specimens led to a greater increase of its absorption ratio during the artificial accelerated weathering test. The volcanic breccia specimens showed the greatest increase of absorption ratio and the biggest reduction ratio of the point- load strength during the tests. These results could aid prediction of the weathering rate of rocks in Ulleungdo island subjected to weathering processes; trachyte which appears to accelerate with time, and volcanic breccia whose mechanical strength can largely decrease in a relative short period of time. Proper measures therefore appear necessary for the prevention of natural disaster such as rock fall and landslide around the circuit road.

• The Journal of Engineering Geology
• /
• v.18 no.4
• /
• pp.567-576
• /
• 2008

It is possible to understand rainfall infiltration characteristics by identification of wetting front in the soil. The wetting front by rainfall infiltration has close relationships among soil density, grain size distribution, and permeability coefficient in the soil. The infiltration velocity is a similar concept of permeability coefficient in the soil. In this study, infiltration velocity of rainfall was calculated by a field monitoring of volumetric water contents at the depths of 50 cm and 80 cm below the surface in the gneiss weathered soil. The calculated field infiltration velocity was compared with a permeability coefficient by a laboratory soil test using undisturbed soil samples in the study area. The permeability coefficient of the soil sample is $3.15{\times}10^{-3}cm/sec$, while the field infiltration velocity is $1.87{\times}10^{-3}cm/sec$. It is interpreted that the lower infiltration velocity is induced by complicate condition of porosity and grain size distribution of soil in the field. The rainfall intensity which influences on the volumetric water content and infiltration velocity is more than 20 mm/day resulting in expansion of wetting front in the soil.

• Journal of Elementary Mathematics Education in Korea
• /
• v.13 no.2
• /
• pp.193-210
• /
• 2009

This research were to develop and apply an educational program for 6th grade students in mathematics by using level orientated teaching method and to make an analysis of their effects on students' mathematics learning achievements and mathematical disposition. Those purposes is following: First, we develop the level orientated teaching method that fits to the low level and high level students and analyze the effect on students' mathematics learning achievements. Second, we analyze the effect on students' mathematical disposition by using level orientated teaching method. The biggest problem of applying level orientated teaching method is that all the groups should do the meaningful activity while just one group is on process. So we tried to keep the proposition that level orientated teaching method should be helpful to both high and low level students. The duration of the research was about 8 weeks from march 2 to may 22 and the level orientated mathematics program consists in lesson 1 "a fraction and a decimal" to lesson 3 "The range of numbers". The results of this study are as follows : First, there was significant effect to the students, develop level orientated mathematics program and using that program. Second, there was an affirmative effect to the students about mathematical disposition using level orientated mathematics program. To sum up conclusion of this study, the level orientated mathematics program has an affirmative effect on mathematics learning achievements and mathematical disposition. We expect further research about level orientated teaching method and use effective level orientated teaching method widely.

• Journal of Elementary Mathematics Education in Korea
• /
• v.21 no.4
• /
• pp.663-686
• /
• 2017

The purpose of this study was to identify the effects of convergent approach of mathematics education on students' problem-solving ability and self-efficacy by designing and applying mathematics curriculum based on STEAM. The results are as follows. First, the test results between the two groups did not show any statistically significant difference in terms of problem solving ability, but the experimental group showed a higher average score than the comparative group. Compared with the standard deviation of the experimental group, It can be seen that the level of difference between students is great. This suggests that STEAM-based mathematics lessons have a positive effect on the problem solving ability of low-level students. Second, the results of the self-efficacy t-test of STEAM-based mathematics class showed statistically significant results at a 5% significance level. In the sub-domain, the preference for the difficulty of the mathematics task, except math self-confidence and the math self-regulation efficacy, were statistically significant at a 5% significance level. This study shows that STEAM-based mathematics classes have a positive effect on the students' positive aspects. Through the STEAM program, students learn that mathematics is connected with other fields, and it provides an opportunity to explore on their own, and they more became interested, motivated, and achievement. Also, through the results of the STEAM-based mathematics class, it can be seen that the expressive power and self-confidence are increased by using the non-formal representation outside of the existing formal representation center. The result of this study can be summarized as follows: A STEAM-based mathematics class has a positive effect on problem solving ability and self-efficacy. Therefore, it is interpreted that the application of the STEAM program focusing on mathematics accounts for education effectives.

• Journal of Sensor Science and Technology
• /
• v.8 no.3
• /
• pp.239-246
• /
• 1999

A highly sensitive photovoltaic infrared photodiode was fabricated for detecting infrared light in $3{\sim}5\;{\mu}m$ wavelength range on InSb wafer with p-i-n structure grown by MOCVD. Silicon dioxide($SiO_2$) insulating films for the junction interface and surface of photodiode were prepared using RPCVD because InSb has low melting point and evaporation temperature. After formation of In ohmic contacts by thermal evaporation, the electrical properties of the photodiode were characterized in dark state at 77K. A product of zero-bias resistance and area($R_0A$) showed $1.56{\times}10^6\;{\Omega}{\cdot}cm^2$ that satisfied BLIP(background limited infrared photodetector) condition. When the photodiode was tested under infrared light, the normalized detectivity of about $10^{11}\;cm{\cdot}Hz^{1/2}{\cdot}W^{-1}$ was obtained. we successfully fabricated a unit cell with InSb IR array with good quantum efficiency and high detectivity.

• Clinics in Shoulder and Elbow
• /
• v.10 no.2
• /
• pp.160-166
• /
• 2007

Purpose: The current study assessed the factors affecting outcomes of primary repair procedures in tears of multiple rotator cuff tendons. Materials and Methods: Among the cases of rotator cuff tears involving two or more tendons receiving operations between 1997 and 2003, The clinical results of 19 cases with more than 2 years follow-up were evaluated by the UCLA score. We evaluated the correlation of trauma, active motion, acromiohumeral distance, tear size, and surface area with the UCLA score using Pearson's linear correlation coefficient (PLCC). Results: UCLA scores increased significantly in all cases, from 9 to 26.1 on average. However, the results were good in 53%, and poor in 47% according to Ellman's criteria. Trauma, active elevation, acromiohumeral distance, and tear size did not correlate with the UCLA score, but the tear surface area was inversely correlated with the score (PLCC=-0.696). Cases with degeneration of the infraspinatus muscle above Goutallier grade III on MRI showed worse results than cases with less degeneration. Conclusion: The clinical results of primary repair of rotator cuff tears involving multiple tendons were satisfactory in 53% of patients. Large tear surface area and severe degeneration of the infraspinatus were poor prognostic factors.

• Journal of Embryo Transfer
• /
• v.30 no.3
• /
• pp.219-224
• /
• 2015

The purpose of this study is to develop transgenic cell line expressing targeted human granulocyte colony stimulating factor (hGCSF) and green fluorescence protein (GFP) genes as well as production of Somatic Cell Nuclear Transfer (SCNT) embryos derived from co-expressed transgenic donor cells. Constructed pPiggy-mWAP-hGCSF-EF1-GFP vector was chemically transfected into bovine fetus cells and then, only GFP expressed cells were selected as donor cells for SCNT. Cleavage and blastocyst rates of parthenogenetic, SCNT embryos using non-TG cell and hGCSF-GFP dual expressed SCNT embryos were examined (cleavage rate: $78.0{\pm}2.8$ vs. $73.1{\pm}3.2$ vs. $70.4{\pm}4.3%$, developmental rate: $27.2{\pm}3.2$ vs. $21.9{\pm}3.1$ vs. $17.0{\pm}2.9%$). Result indicated that cleavage and blastocyst rates of TG embryos were significantly lower (P<0.05) than those of parthenogenetic and non-TG embryos, respectively. In this study, we successfully produced hGCSF-GFP dual expressed SCNT embryos and cryopreserved to produce transgenic cattle for bioreactor system purpose. Further process of our research will transfer of transgenic embryos to recipients and production of hGCSF secreting cattle.

• Journal of Embryo Transfer
• /
• v.30 no.3
• /
• pp.121-128
• /
• 2015

The objective of this study was to evaluate the efficiency of sperm cryosurvival in boar sperm separated by Percoll containing antioxidant enzymes. The boar semen was collected into a pre-warmed ($37^{\circ}C$) thermos bottle by gloved-hand method and was separated by 65% Percoll with superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) before freezing. The frozen sperm was thawed at $38.5^{\circ}C$ for 45 sec in water-bath for sperm characteristic analysis. The sperm were estimated with SYBR14/PI double staining for viability, FITC-PNA/PI double staining for acrosome reaction, Rhodamine123/PI double staining for mitochondrial integrity and were analyzed using flow cytometry. In results, sperm viability, acrosome reaction and mitochondrial integrity were improved in separated sperm groups compared with unseparated sperm by Percoll (UP) group. Especially, viability was significantly higher in sperm separated by Percoll containing 400 IU CAT group compared with other groups (P<0.05). And acrosome reaction was decreased in sperm separated by Percoll with 300 IU SOD, 400 IU CAT and 0.5 mM GSH groups compared with other groups, however, there were no significantly difference mitochondrial integrity among sperm separated by Percoll with antioxidant enzymes. In conclusion, we suggest that use of Percoll containing antioxidant enzymes for sperm separation will be beneficial for sperm cryopreservation in pigs.

• Journal of Embryo Transfer
• /
• v.32 no.3
• /
• pp.139-146
• /
• 2017

The objective of this study was to determine the effect of fructose that was supplemented to a chemically defined in vitro maturation (IVM) medium on oocyte maturation and embryonic development after parthenogenesis in pigs. The base medium for in vitro maturation (IVM) was porcine zygote medium (PZM) that was supplemented with 0.05% (w/v) polyvinyl alcohol (PVA) or 10% (v/v) porcine follicular fluid (pFF). In the first experiment, when immature pig oocytes were matured in a chemically defined medium that was supplemented with 5.5 mM glucose or with 1.5, 3.0 and 5.5 mM fructose, 3.0 mM fructose resulted in a higher nuclear maturation (91.5%) than 1.5 and 5.5 mM fructose (81.9 and 81.9%, respectively) but showed a similar result with 5.5 mM glucose (94.2%). However, there was no significant differences among groups in the embryo cleavage (89.4-92.4%), blastocyst formation (37.5-41.1%), and mean cell number of blastocyst (30.8-34.2 cells). Fructose at the concentration of 3.0 mM (1.08 pixels/oocyte) resulted in a higher intra-oocyte glutathione (GSH) content than 1.5 and 5.5 mM fructose (1.00 and 0.87 pixels/oocytes, respectively) while the cumulus cell expansion was not influenced. In the second experiment, effect of individual and combined supplementation of a chemically defined maturation medium with 5.5 mM glucose or 3.0 mM fructose was examined. No significant effect was found in the nuclear maturation (86.3-92.6%). Embryo cleavage was significantly increased by the combined supplementation with glucose and fructose (95.2%) compared to that with 3.0 mM fructose only (85.7%) while blastocyst formation (37.3-42.8%) and embryonic cell number (33.3-34.1 cells) were not altered. Effect of supplementation of pFF-containing medium with glucose and fructose + glucose was examined in the third experiment. No significant effect by the supplementation with glucose and fructose or glucose alone was observed in the nuclear maturation of oocytes (90.7-94.1%) and blastocyst formation (51.0-56.5%). Our results demonstrate that 3.0 mM fructose was comparable to 5.5 mM glucose in supporting in vitro oocyte maturation and embryonic development after parthenogenesis and could be used as an alternative energy source to glucose for in vitro maturation of pig oocytes.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.8 no.2
• /
• pp.123-136
• /
• 1996

A three-dimensional Galerkin-FEM model which can handle the temporal and spatial variation of density is presented. The hydrostatic approximation is used and density effects are included by means of conservation equation of heat and the equation of state. The finite difference grids are used in the horizontal plane and a set of linear-shape functions is used for the vertical expansion. The similarity transform is introduced to solve resultant matrix equations. The proposed model was first applied to the density-driven circulation in an idealized basin in the presence of the heat exchange between the air and the sea. The advection terms in the momentum equation were ignored, while the convection terms were retained in the heat equation. Coefficients of the vertical eddy viscosity and diffusivity were fixed to be constant. Calculation in a non-rotating idealized basin shows that the difference in heat capacity with depth gives rise to the horizontal gradient of temperature. Consequently, there is a steady new in the upper layer in the direction of increasing depth with compensatory counter flow .in the lower layer. With Coriolis force, geostrophic flow was predominant due to the balance between the pressure gradient and the Coriolis force. As a test in region of irregular topography, the model is applied to the Yellow Sea. Although the resultant flow was very complex, the character of the flow Showed to be geostrophic on the whole.