• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.7
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• pp.563-567
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• 2011

The most widely used piezoelectric ceramics are lead oxide based ferroelectrics (PZT). However, the toxicity of lead oxide and its high vapor pressure during processing have led to a demand for alternative lead-free piezoelectric materials. We synthesized Lead-free piezoelectric ceramics of $0.96(K_{0.5}Na_{0.5})NbO_3-0.04SrZrO_3+x$ mol% $ZrO_2$ [KNN-SZ+$xZrO_2$; x= 0~0.10] doped with 0.1 wt% $MnO_2$ by a conventional solid state method. We investigated the piezoelectric properties and microstructures of these disk samples sintered in reduced atmosphere in order to evaluate the possibility of the multilayered piezoelectric ceramics having the base metal such as Ni as a internal electrode. All of these KNN-SZ samples sintered in 3%$H_2-97%N_2$ atmosphere at $1,140^{\circ}C$ exhibit pure perovskite structure irrespective of the content of $ZrO_2$. Meanwhile, the sintering denisty and piezoelectric properties such as $K_p$, $Q_m$ and $d_{33}$ of KNN-SZ samples as a function of $ZrO_2$ content show the maxima ($k_p$=28.07%, $Q_m$= 101.34, $d_{33}$= 156 pC/N) at x= 0.04 and it is likely that there is some morphotropic phase boundary(MPB) in this KNN-SZ+$xZrO_2$ composition system. These results indicate that the ceramic composition is a promising candidate material for applications in lead free multilayer piezoelectric ceramics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.397-404
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• 1992

The mitotic cycle duration(MCD) and component phase periods of rice(Oryza sativa L.) root meristem cells on the different salt concentrations were investigated by using of tritiated thymidine. The time interval between the maxima of sequential mitotic appearances of marked cells was used as criteria in measuring the MCD of rice. The MCD of rice cultivars 'Seomjinbyeo and Chilseongbyeo' at 0.0%, 0.3%, and 0.6% of salt concentrations appeared the same period as 12hr. The durations of component phase of rice cultivar 'Seomjinbyeo' were the almost same periods at 0.1%, 0.3%, and 0.6% of salt, but in 'Chilseongbyeo' cultivar the G1 and G2 periods were shorter while the S period was longer at 0.3% and 0.6% of salt. Deoxyribonucleic acid(DNA) and protein synthesis were increased while ribonucleic acid(RNA) synthesis was decreased with increasing salt concentrations at Chilseombyeo roots. In Seomjinbyeo roots, DNA and RNA synthesis were decreased while protein synthesis was increased with increasing salt concentrations. These results suggest that DNA, RNA, and protein synthesis may not affect the MCD in rice, but the increase of protein synthesis may be related to the salt tolerance of rice.

• The Journal of Engineering Geology
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• v.25 no.1
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• pp.67-81
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• 2015

A FORTRAN program was developed to determine the optimal locations of multiple recharge wells in an aquifer with different arrangements of pumping wells. The simulated annealing algorithm was used to find optimal locations of two recharge wells which satisfied three objective functions. The model results show that locating two injection wells inside the cluster of pumping wells is efficient if the recovery rate only was taken into account. In contrast, placing injection wells to the side of the cluster is desirable if the simulation considers aggregate objective function. Therefore, installing an injection well on each side of the cluster seems to yield the maximum recovery rates for the existing pumping wells, and it yields similar increases in pumping rate for all wells in the cluster. The locations of recharge wells can be arranged in numerous configurations, because there are multiple near-optimal local minima or maxima. These results indicate that the simulated annealing can yield effective evaluations of the optimal locations of multiple recharge wells. In addition, the suggested aggregate objective function can be utilized as an appropriate multi-objective optimization.

• Ocean and Polar Research
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• v.28 no.1
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• pp.1-12
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• 2006

Analyses of sedimentological and geochemical parameters from two radiocarbon-dated sediment cores (JM98-845-PC and JM98-818-PC) retrieved from the central part of Isfjorden, Svalbard, in the Arctic Sea, reveal detailed paleoclimatic and paleoceanographic histories over the last 15,000 radiocarbon years. The overconsolidated diamicton at the base of core JM98-845-PC is supposed to be a basal till deposited beneath pounding glacier that had advanced during the LGM (Last Glacial Maximum). Deglaciation of the fjord commenced after the glacial maximum, marked by the deposition of interlaminated sand and mud in the ice-proximal zone by subglacial meltwater discharge, and prevailed between 13,700 and 10,800 yr B.P. with enriched-terrigenous organic materials. A return to colder conditions occurred at around 10,800 yr B.P. with a drop in TOC content, which is probably coincident with the Younger Dryas event in the North Atlantic region. At this time, an abrupt decrease of TOC content as well as an increase in C/N ratio suggests enhanced terrigenous input due to the glacial readvance. A climatic optimum is recognized between 8,395 and 2,442 yr B.P., coinciding with 'a mid-Holocene climatic optimum' in Northern Hemisphere sites (e.g., the Laurentide Ice sheet). During this time, as the sea ice receded from the fjord, enhanced primary productivity occurred in open marine conditions, resulting in the deposition of organic-enriched pebbly mud with evidence of TOC maxima and C/N ratio minima in sediments. Fast ice also disappeared from the coast, providing the maximum of IRD (ice-rafted debris) input. Around 2,442 yr B.p. (the onset of Neoglacial), pebbly mud, characterized by a decrease in TOC content, reflects the formation of more extensive sea ice and fast ice, which might cause decreased primary productivity in the surface water, as evidenced by a decrease in TOC content. Our results provide evidence of climatic change on the Svalbard fjords that helps to refine the existence and timing of late Pleistocene and Holocene millennial-scale climatic events in the Northern Hemisphere.

• Applied Biological Chemistry
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• v.41 no.1
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• pp.31-41
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• 1998

A carotenoprotein from the muscle of Ascidian (Halocynthia roretzi) was purified by ion exchange chromatography and gel filtration chromatography, and analyzed molecular weight, stability of pH and heat, effect of denaturing agents, amino acids and fatty acids composition. The purified carotenoprotein had absorption maxima of 463 nm and 439 nm. The carotenoprotein had an approxmimate molecular weight of 64.4 kDa in polyacrylamide gel electrophoresis. The amino acid compositions of carotenoprotein were mainly Gly (15.39%), Asn (11.31%), Gln (10.62%) and Ser (13.35%). The major fatty acids composition of carotenoprotein were $C_{16:1(n-7)}\;(15.4%)$, $C_{22:1(n-9)}\;(14.5%)$ and $C_{20:1(n-11)}\;(11.4%)$. The monounsaturated fatty acids (45.2%) contained abundant content compared to other saturated (38.1%) and polyunsaturated (11.7%) fatty acids.

• Journal of KIISE:Software and Applications
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• v.37 no.2
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• pp.104-109
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• 2010

The lighting reflection is a common problem in image analysis and causes the many difficulties to extract distinct features in related fields. Furthermore, the problem grows in the rainy night. In this paper, we aim to remove light reflection effects and reconstruct a road surface without lighting reflections in order to extract distinct features. The proposed method utilizes a 3D analysis based on a multiple geometry using captured images, with which we can combine each reflected areas; that is, we can remove lighting reflection effects and reconstruct the surface. At first, the regions of lighting sources and reflected surfaces are extracted by local maxima based on vertically projected intensity-histograms. After that, a fundamental matrix and homography matrix among multiple images are calculated by corresponding points in each image. Finally, we combine each surface by selecting minimum value among multiple images and replace it on a target image. The proposed method can reduces lighting reflection effects and the property on the surface is not lost. While the experimental results with collected data shows plausible performance comparing to the speed, reflection-overlapping areas which can not be reconstructed remain in the result. In order to solve this problem, a new reflection model needs to be constructed.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.7
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• pp.962-970
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• 2012

This study aimed to investigate the effects of ruminal infusion of garlic oil (GO) on fermentation dynamics, fatty acid (FA) profile, and abundance of bacteria involved in biohydrogenation in the rumen. Six wethers fitted with ruminal fistula were assigned to two groups for cross-over design with a 14-d interval. Each 30-d experimental period consisted of a 27-d adaptation and a 3-d sample collection. Goats were fed a basal diet without (control) or with GO ruminal infusion (0.8 g/d). Ruminal contents collected before (0 h) and at 2, 4, 6, 8, and 10 h after morning feeding were used for fermentation analysis, and 0 h samples were further used for FA determination and DNA extraction. Garlic oil had no influence on dry matter intakes of concentrate and hay. During ruminal fermentation, GO had no effects on total VFA concentration and individual VFA molar proportions, whereas GO increased the concentrations of ammonia nitrogen and microbial crude protein (p<0.05). Compared with control, GO group took a longer time for total VFA concentration and propionate molar proportion to reach their respective maxima after morning feeding. The ratio of acetate to propionate in control reduced sharply after morning feeding, whereas it remained relatively stable in GO group. Fatty acid analysis showed that GO reduced saturated FA proportion (p<0.05), while increasing the proportions of C18, t11-18:1 (TVA), c9,t11-conjugated linoleic acid (c9,t11-CLA), t10,c12-CLA, and polyunsaturated FA (p<0.05). The values of TVA/(c9,t11-CLA+TVA) and C18:0/(TVA+C18:0) were reduced by GO (p<0.05). Real-time PCR showed that GO tended to reduce Butyrivibrio proteoclasticus abundance (p = 0.058), whereas GO had no effect on total abundance of the Butyrivibrio group bacteria. A low correlation was found between B. proteoclasticus abundance and C18:0/(TVA+C18:0) (p = 0.910). The changes of fermentation over time suggested a role of GO in delaying the fermentation process and maintaining a relatively modest change of ruminal environment. The inhibitory effects of GO on the final step of biohydrogenation may be related to its antibacterial activity against B. proteoclasticus and other unknown bacteria involved.

• Ocean and Polar Research
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• v.26 no.2
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• pp.273-286
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• 2004

The effects of environmental forcing on autotrophic picoplankton distributional patterns were investigated for convergence ($5^{\circ}N$), divergence ($9^{\circ}N-10^{\circ}30'N$) and oligotrophic ($17^{\circ}N$) sites in the tropical eastern Pacific during 2001 and 2003 KODOS (Korea Deep Ocean Study) cruises. The distributions of picoplankton populations - Prochlorococcus, Synechococcus and picoeukaryotes algae - were determined by flow cytometric analyses. Latitudinal variations in abundance maxima, vertical profiles, integrated abundance (0-150 m), and estimated carbon biomass were contrasted for each site according to three hydrological conditions. Prochlorococcus showed consistently high abundance in the surface mixed layers of all sites at $1\;{\times}\;10^5{\sim}3\;{\times}\;10^5\;cells\;ml^{-1}$ and showed declining abundance below these layers. However, these decreasing rates were not particularly sharp showing considerably high abundance at $1\;{\times}\;10^4\;cells\;ml^{-1}$ or higher even at 100 m depth. Vertical profiles of Synechococcus and picoeukaryotes were generally parallel to each other in all sites. A clear abundance maximum was observed at divergence site at or slightly above the pycnocline depth. Higher abundance was observed at the surface mixed layer for convergence site but a sharp decrease was observed below the pycnocline. However, there was no significant abundance fluctuation with depth at more oligotrophic site ($17^{\circ}N$). Integrated cell abundance of Prochlorococcus was high in the oligotrophic site at $2.17\;{\times}\;10^{13}\;m^{-2}$, and low in the convergence site at $0.88\;{\times}\;10^{13}\;m^{-2}$. However, opposite pattern was observed for Synechococcus and picoeukaryotes where relatively high integrated cell abundance was shown in the convergence site. Estimated carbon biomass of Prochlorococcus contributed 30.4-80.3% of total autotrophic picoplankton carbon showing the highest contribution in the oligotrophic site and the lowest contribution in the convergence site. Synechococcus contribution of total autotrophic picoplantkon carbon biomass was lower than 5.8% for most of sites except the convergence site where Synechococcus contributed 23.2% of picoplankton carbon biomass. Carbon biomass of picoeukaryotes was 18.8-46.4% showing the highest carbon biomass at the convergence site. Overall, Prochlorococcus showed higher cell abundance and carbon biomass and exhibited different reaction to hydrological conditions when compare with the other two major autotrophic picoplankton groups.

• Journal of Korea Water Resources Association
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• v.42 no.10
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• pp.857-866
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• 2009

In this study, basic data is consisted annual maximum rainfall at 56 stations that has the rainfall records more than 30years in Korea. The 14 probability distributions which has been widely used in hydrologic frequency analysis are applied to the basic data. The method of moments, method of maximum likelihood and probability weighted moments method are used to estimate the parameters. And 4-tests (chi-square test, Kolmogorov-Smirnov test, Cramer von Mises test, probability plot correlation coefficient (PPCC) test) are used to determine the goodness of fit of probability distributions. This study emphasizes the necessity for considering the variability of the estimate of T-year event in hydrologic frequency analysis and proposes a framework for evaluating probability distribution models. The variability (or estimation error) of T-year event is used as a criterion for model evaluation as well as three goodness of fit criteria (SLSC, MLL, and AIC) in the framework. The Jackknife method plays a important role in estimating the variability. For the annual maxima of rainfall at 56 stations, the Gumble distribution is regarded as the best one among probability distribution models with two or three parameters.

• Food Science and Preservation
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• v.16 no.2
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• pp.266-275
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• 2009

To develop new high-quality Yakchobugak, features of Lactococcus lactis-fermented waxy rice paste after addition of some colored powdered agro-food products were investigated. Total and reducing sugars of waxy rice paste fermented by lactic acid bacteria were higher than those of control raw waxy rice paste. Total acidity gradually increased as powder concentration rose, being 1.02-1.56% and 0.96-1.87% in samples fermented with Cucurbita maxima and Capsicum annuum powders, respectively; these values were 3-4 times those in rice fermented with other powders. Fermented waxy rice paste viscosities were lower than those of non-fermented samples. The viscosities of samples fermented with Curcuma longa and Opuntia ficus powders were in the range $100-160{\times}10^4$ centipoise($mPa{\cdot}s$), and those of pastes fermented with Robus coreanus and Camellia sinensis extracts were under $40{\times}10^4mPa{\cdot}s$. Hunter color lightness(L) values decreased and yellowness(b) values rose after fermentation. Waxy rice paste fermented with Robus coreanus showed uniform particle size distribution, and many pores, by scanning electron micrography.