• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.9-19
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• 2001

This study was carried out to investigate natural insectifuge materials from tree extractives in order to substitute for organic synthetic insecticides for food wrapping corrugated board. Tree samples were collected, extracted, fractionated with hexane, $CH_2Cl_2$, ethylacetate(EtOAc) and $H_2O$, and then freezed dried for further study. EtOAc or $H_2O$ fractions were chromatographed on a Sephadex LH-20 column for isolation and purification, and the isolated compounds were characterized by spectroscopic tools such as NMR and MS. Crude extractives of EtOAc and $H_2O$ fractions were added to the printing ink for corrugated board with the concentration of 2% or 3% based on the weight of the ink, then the prepared ink was printed on the corrugated board to be used for evasion test using larva of indian meal moth(Plodia interpunctella(Hubner)). Robtin, dihydrorobinetin and leucorobinetinidin were isolated from the wood extractives of black locust(Robinia pseudoacacia) and the bark of poplar(Populus alba $\times$ glandulosa) contained many kinds of compounds such as (+)-catechin, naringenin, aromadendrin, eriodictyol, sakuranetin and its glycoside, taxifolin, neosaturanin, salireposide, p-coumaric acid and aesculin. Much of (+)-catechin was isolated from the bark extractives of willow(Salix koreensis) in addition to (+)-gallocatechin and p-coumaric acid and the bark of weeping willow(Salix babylonica) also contained (+)-catechin, (+)-gallocatechin, dihydromyricetin and myricetin.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.3
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• pp.43-49
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• 2010

Direct printing technology is an attractive metallization method, which has become immerging as "Green technology" to the conventional photolithography, on account of low cost, simple process and environment-friendliness. In order to commercialize the printed electronics in industry, it is essential to evaluate the electrical properties of conductive circuits using direct printing technology. In this contribution, we focused on the electrical characteristics of inkjet-printed circuits. A Cu nanoink was inkjet-printed onto a Bisaleimide triazine(BT) substrate with parallel transmission line(PTL) and coplanar waveguide(CPW) type, then was sintered at $250^{\circ}C$ for 30 min. We calculated the resistivity of printed circuits through direct current resistance by the measurement of I-V curve: the resistivity was approximately 0.558 ${\mu}{\Omega}{\cdot}cm$ which is about 3.3 times that of bulk Cu. Cascade's probe system in the frequency range from 0 to 30 GHz were employed to measure the Scattering parameter(S-parameter) with or without a gap between the substrate and the probe station chuck. The result of measured S-parameter showed that all printed circuits had over 5 dB of return loss in the entire frequency range. In the curve of insertion loss, $S_{21}$, showed that the PTL type circuits had better transmission of radio frequency (RF) than CPW type.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.69-80
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• 1999

Recently, social requirements of personal identification techniques are rapidly expanding in a number of new application ares. Especially fingerprint recognition is the most important technology. Fingerprint recognition technologies are well established, proven, cost and legally accepted. Therefore, it has more spot lighted among the any other biometrics technologies. In this paper we propose a new on-line fingerprint recognition algorithm for non-inked type live scanner to fit their increasing of security level under the computing environment. Fingerprint recognition system consists of two distinct structural blocks: feature extraction and feature matching. The main topic in this paper focuses on the feature matching using the fingerprint minutiae (ridge ending and bifurcation). Minutiae matching is composed in the alignment stage and matching stage. Success of optimizing the alignment stage is the key of real-time (on-line) fingerprint recognition. Proposed alignment algorithm using clique shows the strength in the search space optimization and partially incomplete image. We make our own database to get the generality. Using the traditional statistical discriminant analysis, 0.05% false acceptance rate (FAR) at 8.83% false rejection rate (FRR) in 1.55 second average matching speed on a Pentium system have been achieved. This makes it possible to construct high performance fingerprint recognition system.

• Journal of the Korean Geosynthetics Society
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• v.10 no.3
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• pp.25-32
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• 2011

The matric suction and volumetric water content of dredging soils obtained from Saemangeum area were measured by the automated Soil-Water Characteristic Curve (SWCC) apparatus under both drying and wetting conditions. Based on the test result, SWCCs of the dredging soils were estimated by the van Genuchten(1980) model. The matric suction of drying process is larger than that of wetting process at a same effective degree of saturation. The suction stresses for various matirc suctions were estimated using Lu and Likos(2006) model and the Suction Stress Characteristic Curves (SSCC) were predicted using the independent parameter of SWCC. The suction stress of drying path was increased and decreased, while the suction stress of wetting path was continuously decreased with increasing the effective degree. Also, the suction stress of drying path is larger than that of wetting path at a same effective degree of saturation. The Hydraulic Conductivity Function(HCF) was also predicted by the van Genuchten(1980) model. The hydraulic conductivity was increased with increasing the volumetric water content. The hydraulic conductivity of drying path is larger than that of wetting path at a same matric suction. According to the results of SWCCs and SSCCs, the hysteresis phenomenon of suction stress or matric suction during both drying and wetting paths was occurred. The main reason of hysteresis phenomenon is a ink bottle effect of water among soil particles.

• Analytical Science and Technology
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• v.28 no.1
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• pp.26-32
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• 2015

The consistency and homogeneity of repetitive printing of artificial fingerprint were evaluated using a visual minutiae comparison method and an Automated Fingerprint Identification System (AFIS). The standard latent fingerprint pattern was prepared by the printing of a master digital fingerprint pattern with an inkjet printer cartridge case filled with artificial sweat. The master digital fingerprint pattern was prepared with a scanning of an inked fingerprint pattern of a living subject. The intensities of the master digital fingerprint pattern were adjusted by changing the 'output level' values of the Adobe Photoshop CS 5 software. Number of standard latent fingerprint patterns were printed and then developed with conventional latent fingerprint developing methods; ninhydrin treatment method and 1,2-indandion(1,2-IND)/$ZnCl_2$ treatment method. The ridge details of the latent fingerprint patterns developed with the reagents were visually compared with the inked fingerprint pattern and could confirm that the minutiae of both patterns are visually identical. The ridge detail of the inked fingerprint and reagent developed standard latent fingerprint patterns were compared with an AFIS. The average number of minutiae searched by the AFIS was $52.4{\pm}2.4$ (range = 48~56) for 50 ninhydrin developed latent fingerprint patterns, and $50.2{\pm}1.9$ (range = 47~53) for 50 1,2-IND/$ZnCl_2$ developed latent fingerprint patterns. These low standard deviation values over 50 repetitive printing demonstrated that the 50 standard latent patterns were printed with consistent and homogeneous manner.

• Journal of Food Hygiene and Safety
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• v.22 no.2
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• pp.88-92
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• 2007

Isopropylthioxanthone(ITX) is used as a photoinitiator In UV-cured inks, triggering the radical polymerization of the acrylic component of such inks and thus causing the liquid ink film to cure. Recently ITX was detected in carton packed food in Italy. In order to cope with risk issues of overseas and acquire monitoring data on ITX, we have established the method using HPLC/FLD for ITX analysis after reviewing parameters of the analytical methods. Limit of detection (LOD) and limit of quantification (LOQ) were 0.02 ppb and 0.1 ppb, and linearity and RSD (%) were 0.9991 and 1.09, respectively. We have investigated ITX levels migrated to food on 87 commercial products packed in carton and ITX was not detected any food. Therefore it is supposed that UV-cured ink containing ITX as photoinitiator is not currently used in printing of carton pack in Korea.

• Journal of The Korean Association For Science Education
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• v.24 no.5
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• pp.1018-1027
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• 2004

The purpose of this study was to identify and compare the types of scientific questions which were generated by elementary students and preservice teachers on the tasks of scientific observation. To identify the types of scientific questions, 4 observing tasks, dry grapes contained in soda pop, candlelight, celery, and a rock were administered to 40 sixth elementary students and 20 elementary preservice teachers. And then, the types and frequency of scientific questions generated by them were compared. The results showed that the types of scientific questions were classified into conjectural questions, causal questions, predictive questions, methodical questions and applicative questions. Further more, subordinate questions to the above questions were classified into object exploration questions and object verification questions, explicans exploration questions and explicans verification questions, result exploration questions and result verification questions, example exploration questions and example verification questions. Subordinate questions did not come out from the methodical questions. The types of scientific questions generated by elementary students and preservice teachers were identical, however, there were differences in frequency. This study supports that elementary students also have cognitive capability to generate various scientific questions. The results of this study may be used as a teaching strategy for the guidance of the direction and the method of scientific inquiry.

• Journal of the Korean Ceramic Society
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• v.39 no.12
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• pp.1143-1148
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• 2002

Precipitated calcium carbonate is one of the most versatile mineral fillers and is consumed in an wide range of products including paper, paint, plastics, rubber, textiles, sealants, adhesives and printing ink and can be produced by several methods. Calcium carbonate has three isomorphism; vaterite, aragonite and calcite, with numerous variations of morphology in the natural mineral or organism. Formation process of vaterite in the reaction of system $Ca(OH)_2-CH_3OH-H_2O-CO_2$ were investigated by measuring the electrical conductivity, $Ca^{2+}$ ion concentration, pH in the slurries and by means of X-ray diffraction and electron microscopic observation. It was clearly established that the reaction temperature is important variable in the carbonation process; in general over 50${\circ}C$, the vaterite was precipitated with the calcite and aragonite. SEM and XRD observations revealed that the vaterite formation could be prepared the temperature range of 40 to 50${\circ}C$ and mean size of particles in this range is controlled from 0.5 to 0.8 ${\mu}m$.

• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.73-83
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• 2008

The purpose of this study was to investigate the types of conceptions of mixing phenomena related to dissolution and diffusion in high school students. The subjects of the investigation consisted of 108 students who took chemistry I course at 11th grade and 29 students who took chemistry II course at 12th grade. For this study, it was found that the many students had the alternative conception that chalk didn't dissolve in water because chalk was a nonpolar material. Most of the students understood the phenomena which carbon tetrachloride and water will not mix as the attraction conception. But many of the other students understood the phenomenon as characteristic of the materials such as difference of density. Many of the students understood the phenomenon of mixing ethanol and water constantly as ‘Attraction conception'. The phenomenon which is mixed ink and water was just accepted by the most students as the spreading of ink in water without understanding the reason of mixing. The phenomena of mixing iodine and carbon tetrachloride was understood as ‘Space conception' or ‘Attraction conception'. It could be inferred that the diverse alternative conceptions related to dissolution and diffusion phenomena were generated by the absence of entropy concept. Therefore, the explanations of science textbooks related to dissolution and diffusion phenomena need to change for students to understand them correctly.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.4
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• pp.153-159
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• 2015

Inorganic pigments have been received a great attention for various applications including paint, glazed ceramic ink, art tile, and building exterior due to their excellent thermal and chemical stability. Traditionally, the compositions of $PbCrO_4$, CdS and CdSe have been widely used as a yellow inorganic pigment. However, the use of these compositions has been restricted in recent years, because they contain harmful elements such as Cd, Cr, Pb and Se. In this study, new environment-friendly ceria-based pigment was synthesized using solid state reaction. Crystal structure and morphology of the obtained $Ce_{1-x}Zr_xBi_yO_{2-y/2}$ yellow pigment were analyzed using XRD and SEM, respectively. Substitutional effect of Zr and Bi on the pigment color was analyzed using UV-vis. spectrophotometer and CIE $L^*a^*b^*$ analysis. The crystal structure of the obtained pigments was dependent on the calcination temperature. The color characteristics and absorption band of the pigments were dependent on the calcination temperature and Zr, Bi contents. As a result, all the obtained yellow pigments showed the effective absorption ranged from ultraviolet to visible light, and $Ce_{0.44}Zr_{0.36}Bi_{0.20}O_{0.19}$ (x = 0.36, y = 0.20) pigment showed the most brilliant yellow color.