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Fatigue Characteristics of PLZT(x/30/70) Thin Films with Various La Concentrations (La 농도에 따른 PLZT(x/30/70) 박막의 피로 특성에 관한 연구)

  • Kang, Seong-Jun;Chung, Yeun-Gun;Joung, Yang-Hee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.9 no.5
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    • pp.1066-1072
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    • 2005
  • The effects of La concentration in PLZT (z/30/70) thin film prepared by sol-gel method are investigated for the NVFRAM application. As the La concentration increases, the dielectric constants at 10 kHz increase from 450 to 600, while the loss tangent and the leakage current density at 100 kV/cm decrease from 0.075 to 0.025 and from $5.83{\times}10^{-7}\;to\;1.38{\times}10^{-7}\;A/cm^2,$ respectively. In the results of hysteresis loops measured at 175 kV/cm, the remanent polarization and the coercive field decrease from 20.8 to $10.5{\mu}C/cm^2$ and from 54.48 to 32.12 kV/cm, respectively, with the increase of La concentration from 0 to $10mol\%.$ After applying for $10^9$ cycles of square pulses with ${\pm}5V$ height, the remanent polarization of the PLZT (10/30/70) thin film decreases $40\%$ from the initial state, while that of the PLZT (10/30/70) thin film decreases $64\%.$.

The Effects of Two Inoculants Applied to Forage Sorghum at Ensiling on Silage Characteristics

  • Guan, Wu-tai;Ashbell, G.;Hen, Y.;Weinberg, Z.G.
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.2
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    • pp.218-221
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    • 2002
  • Whole forage sorghum (saccharatum) cultivar FS5 was harvested at the soft dough ($303{\pm}9g\;kg^{-1}$ DM) stage of maturity. The sorghum was chopped into approximately 20 mm pieces and ensiled under laboratory conditions in 1.5 L Weck glass jars. At ensiling, it was treated with two commercial silage inoculants: Pioneer 1188 (Inoculant A) and Eco-corn (Inoculant B). The inoculant A and B was applied at ca $2{\times}10^5$ or $2{\times}10^4$ colony forming units $g^{-1}$ DM., respectively. Silage with no additives served as a control. Three jars per treatment were opened on days 2, 4, 8, 15 and 60 post-ensiling to study fermentation dynamics. After 60 days of ensiling the silages were analyzed and subjected to an aerobic stability test lasting 5 days. Results showed that both inoculants caused a more rapid rate of pH decrease and a higher amount of lactic acid production. All the silages were well preserved and were stable upon exposure to air. Inoculants did not influence (p>0.05) the ash and total N contents, but tended to reduce acetic acid (p<0.05), butyric acid (p<0.01) and propionic acid (p<0.01) contents, and to increase the lactic acid content (p<0.01). The lower DM content of silages treated with Inoculant A agrees with the greater gas loss resulting from the DM loss, which was in good agreement with the higher yeast counts upon aerobic exposure. Silage treated with inoculant B had the highest DM (p<0.05) and lactic acid contents (p<0.01), and the lowest acetic acid content (p<0.05), which agrees with the rapid reduction of pH and smaller gas loss. Inoculant B reduced the ADF (p<0.01), ADL and NDF (p<0.05) contents, which also indicates smaller losses of organic soluble material. The control silages contained the highest levels of volatile fatty acids but no lactic acid, indicating secondary fermentation. It was concluded that both inoculants may improve the fermentation process, since silages from all treatments were stable upon aerobic exposure, noadvantage could be attributed to any of the inoculants used.

The Differences of Fixation Method in Proximal Chevron Osteotomy for Hallux Valgus: K-Wire, Cannulated Screw, Plate (무지외반증에서 근위 갈매기형 절골술 후 고정 방법에 따른 차이: K-강선, 유관나사, 금속판)

  • Kim, Taik-Seon;Kim, Hak-Jun;Park, Young-Hwan;Lim, Hyung-Tae
    • Journal of Korean Foot and Ankle Society
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    • v.15 no.2
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    • pp.62-67
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    • 2011
  • Purpose: The authors evaluated the differences between K-wires and Cannulated screw, plate for fixing the proximal metatarsal chevron osteotomy of moderate and severe hallux valgus. Materials and Methods: There were 62 patients (79 feetz) who were moderate and severe degree hallux valgus according to the classification of Mann. They all got the proximal chevron osteotomy when correcting the deformity. We divided the patients into 4 groups, Two K-wire fixed group as A, one cannulated screw fixed group as B. Two cannulated screw fixed group as C, Plate fixed group as D, Group A were patients (26 feet) and Group B were patients z(9 feet), Group C were patients (31 feet) and Group D were patients (13 feet). Preoperative, postoperative and follow-up hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured for each patient. ANOVA test and Student t-test were done for statistical analysis. Results: Mean follow up period was 43.8 months (range: 12~82 months). Preoperative mean IMA was $16.4{\pm}3.5$, $17.7{\pm}11.3$, $17.3{\pm}5.9$ and $16.6{\pm}2.3$ degrees in respectively group A, B, C, D. Immediate postoperative mean IMA was $5.6{\pm}3.4$, $7.3{\pm}4.4$, $7.6{\pm}4.4$ and $6.7{\pm}2.8$ degrees in respectively group A, B, C, D. The final mean IMA was $8.9{\pm}4.5$, $15.2{\pm}7.5$, $10.3{\pm}4.4$ and D $7.7{\pm}3.5$ degrees in respectively group A, B, C, D. There were significant statistical increase in final mean IMA of group B and C (p<0.05). Conclusion: The IMA was significantly increased in the group which used one or two cannulated screw for fixation on follow up, therefore more caution should be needed when using one or two cannulated screw fixation technique after proximal chevron osteotomy.

Studies on the Quick Ripening Process for Soysauce (속양(速釀)간장 제조(製造)에 관(關)한 연구(硏究))

  • Kim, Z.U.;Cho, M.J.
    • Applied Biological Chemistry
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    • v.14 no.1
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    • pp.19-27
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    • 1971
  • This experiment was conducted as a preliminary test to invent the quick ripening process for soysauces. The bran koji extract of 2 kinds of mold (Asp. niger and Asp. sojae) was used as enzyme sources in order to improve the rate of enzymatic conversion of raw materials and shorten the ripening period of soysauces. Soybean koji (inoculated Asp. sojae) and steamed soybean were enzymatically decomposed for 8 hours at $40^{\circ}C$, pH 4-6 with stirring at a rate of 1500 rpm. After the enzymatic treatment, soysauces were fermented by 4 kinds of processes with the above-mentioned salt tolerant microorganisms inoculated. After 4 weeks, sensory evolution for these soysauces products and analysis of chemical components were carried out. The results obtained were summarized as follows. 1. Soysauces prepared from decomposed koji by Asp. niger enzyme complex showed higher extractables, such as total nitrogen, amino nitrogen, pure extract and reducing sugar, than any other procedure. Extracted amounts of each components of soysauces prepared from this process during 1 month were similar to those of soysauces made from general procedure (control) for 5 to 6 months. 2. According to sensory evaluation, soysauce prepared from decomposed koji also showed best taste and were similar to that of soysauces prepared by general method for 6 months.

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The Kinematic Analysis of the Tennis Flat Serve Motion (테니스 플랫 서브 동작의 운동학적 분석)

  • Oh, Cheong-Hwan;Choi, Su-Nam;Nam, Taek-Gil
    • Korean Journal of Applied Biomechanics
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    • v.16 no.2
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    • pp.97-108
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    • 2006
  • C. H. OH, S. N. CHOI, T. G. NAM, The Kinematic Analysis of the Tennis Flat Serve Motion, Korean Jiurnal of Sports Biomechanics, Vol. 16, No. 2, pp. 97-108, 2006. By the comparison and the analysis of the different factors during the tennis flat serve motion such as the required time per section, the movement displacement of the racket, the velocity of the upper limbs joints, the physical center of gravity, and the angle and the angular velocity of the upper limbs joints between an ace player and a mediocre player, these following results were drawn. First, the experiment result of the total time required per section in a tennis flat serve motion showed that an ace player was faster than a mediocre player by 0.4 seconds. This result suggested that it was required to increase the speed of the racket head by a swift swing to perform an effective flat serve motion. Second, the experiment result of the movement displacement of the racket in the tennis flat serve motion showed that an ace player greatly moved toward the left side on an x-axis. But both an ace and a mediocre player were shown to be at the similar points on a y-axis at the moment of the impact of the racket. An ace player was also shown to be located at a higher position on a z-axis by 0.23m. Third, the velocity of the center of gravity of an ace player was faster in every phase than that of a mediocre player in a tennis flat serve motion. Fourth, the velocity of the upper limb joints of an ace player was faster in every phase than that of a mediocre player in a tennis flat serve motion. Fifth, the experiment result of the speed of the racket head in tennis flat serve motion showed that a mediocre player was faster than an ace player in the first phase, but the latter was faster than the former in the second, third, and the fourth phases. Sixth, at the moment of impact of a tennis flat serve, an ace player had greater flexion of the angle of the wrist joints by an 11.8 degree than a mediocre player. An ace player also had greater extension of the angle of the elbow joint and the shoulder joint respectively by a 5.2 degree and a 1.4 degree with a mediocre player. Seventh, an ace player had greater angular velocity of the upper limb joints and the hip joints than a mediocre player at the moment of the impact of tennis flat serve. Eighth, an ace player was shown to have a greater change of the forward and the backward inclination (or the anterior and posterior inclination) of the upper body

Studies on Color and Rheological Properties in Strawberry Jam (딸기쨈의 색깔과 물성에 관한 연구)

  • Lee, Jong Hyeouk;Chang, Kyu Seob;Yoon, Han Kyo
    • Korean Journal of Agricultural Science
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    • v.14 no.1
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    • pp.134-143
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    • 1987
  • In order to observe the strawberry as the raw materials and to compare the color of strawberry's products, Hunter L,a,b tristimulate color values were measured physically by color difference meter. Food textural properties of strawberry were measured by Rheo textural meter for rheological properties of strawberry jam. According to results obtained, it showed that Hunter L,a,b tristimulus color values were affected by ripening time of strawberry and Hunter color values changed regularly on different pH. Deformation of red color pigment Hunter color values changed linearlly on different pH, therefore red color pigment of elderberry showed to be used as a food color agent. The first peak of strawberry in TPA curve was high as cherry, grape and pineapple Strawberry jam showed pseudoplastic characteristic and time dependence.

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Shear Bond Strength Comparison of Different Adhesive Systems to Calcium Silicate-based Materials (Calcium Silicate-based 재료에 대한 수 종 상아질 접착제의 전단결합강도 비교)

  • Shin, Hyunok;Kim, Misun;Nam, Okhyung;Lee, Hyoseol;Choi, Sungchul;Kim, Kwangchul
    • Journal of the korean academy of Pediatric Dentistry
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    • v.45 no.4
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    • pp.445-454
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    • 2018
  • The aim of this study was to measure the shear bond strength (SBS) of different adhesive systems to calcium silicate-based materials (Biodentine and RetroMTA). Eighty cylindrical acrylic blocks, with a hole (5.0 mm diameter, 2.0 mm height) in each, were prepared. The holes were filled with Biodentine (BD) and RetroMTA (RMTA), and the specimens were divided into 2 groups. Each group was classified into 4 subgroups: Clearfil$^{TM}$ SE (CSE) ; AQ bond (AQ) ; All bond universal Self-etch (ABU-SE) ; and All bond universal Total-etch (ABU-TE). After the application of different adhesive systems, composite resin (Z350) was applied over BD and RMTA. The SBS was measured using a universal testing machine, and the data were compared using the Kruskal-Wallis test and the Mann-Whitney test. The highest and lowest values of SBS were observed for BD-ABU-SE and RMTA-AQ, respectively. No significant differences were found in the SBS between ABU-TE and ABU-SE and between ABU-TE and CSE to BD and RMTA. According to the data, BD showed a higher SBS than did RMTA when BD and RMTA are compared in the same adhesive agents. Further, among all groups, composite resin with ABU-SE showed better bond strength to BD and RMTA.

MISCLASSIFIED TYPE 1 AGNS IN THE LOCAL UNIVERSE

  • Woo, Jong-Hak;Kim, Ji-Gang;Park, Daeseong;Bae, Hyun-Jin;Kim, Jae-Hyuk;Lee, Seung-Eon;Kim, Sang Chul;Kwon, Hong-Jin
    • Journal of The Korean Astronomical Society
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    • v.47 no.5
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    • pp.167-178
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    • 2014
  • We search for misclassified type 1 AGNs among type 2 AGNs identified with emission line flux ratios, and investigate the properties of the sample. Using 4 113 local type 2 AGNs at 0.02 < z < 0.05 selected from Sloan Digital Sky Survey Data Release 7, we detected a broad component of the $H{\alpha}$ line with a Full-Width at Half-Maximum (FWHM) ranging from 1 700 to $19090km\;s^{-1}$ for 142 objects, based on the spectral decomposition and visual inspection. The fraction of the misclassified type 1 AGNs among type 2 AGN sample is ~3.5%, implying that a large number of missing type 1 AGN population may exist. The misclassified type 1 AGNs have relatively low luminosity with a mean broad $H{\alpha}$ luminosity, log $L_{H\alpha}=40.50{\pm}0.35\;erg\;s^{-1}$, while black hole mass of the sample is comparable to that of the local black hole population, with a mean black hole mass, log $M_{BH}=6.94{\pm}0.51\;M_{\odot}$. The mean Eddington ratio of the sample is log $L_{bol}/L_{Edd}=-2.00{\pm}0.40$, indicating that black hole activity is relatively weak, hence, AGN continuum is too weak to change the host galaxy color. We find that the O III lines show significant velocity offsets, presumably due to outflows in the narrow-line region, while the velocity offset of the narrow component of the $H{\alpha}$ line is not prominent, consistent with the ionized gas kinematics of general type 1 AGN population.

Studies on the fabrication and properties of $La_ 0.7Sr_0.3MnO_3$cathode contact prepared by glycine-nitrate process and solid state reaction method for the high efficient solid oxide fuel cells applications 0.3/Mn $O_{3}$ (고효율 고체산화물 연료전지 개발을 위한 자발 착화 연소 합성법과 고상반응법에 의한 $La_ 0.7Sr_0.3MnO_3$ 양극재료 제조 및 물성에 관한 연구)

  • Shin, Woong-Shun;Park, In-Sik;Kim, Sun-Jae;Park, Sung
    • Electrical & Electronic Materials
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    • v.10 no.2
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    • pp.141-149
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    • 1997
  • L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders were prepared by both GNP(Glycine-Nitrate Process) and solid state reaction method in various of calcination temperature(800-1000.deg. C) and time in air. Also, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contacts on YSZ(Yttria-Stabilized Zirconia) substrate were prepared by screen printing and sintering method as a function of sintering temperature(1100-1450.deg. C) in air. Sintering behaviors have been investigated by SEM(Scanning Electron Microscope) and porosity measurement. Compositional and structural characterization were carried out by X-ray diffractometer and ICP AES(Inductively Coupled Plasma-Atomic Emission Spectrometry) analysis. Electrical characterization was carried out by the electrical conductivity with linear 4 point probe method. As the calcination period increased in solid state reaction method, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ phase increased. Although L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ single phase was obtained only for 48hrs at 1000.deg. C, in GNP method it was easy to get single and ultra-fine L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders with submicron particle size at 650.deg. C for 30min. The particle size and thickness of L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contact by solid state reaction method did not change during the heat treatment, while those by GNP method showed good sintering characteristics because initial powder size fabricated from GNP method is smaller than that fabricated from solid state reaction method. Based on enthalpy change from thermodynamic data and ICP-AES analysis, it was suggested to make cathode contact in composition of (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$ Mn $O_{3}$ which have little second phase (L $a_{2}$Z $r_{2}$ $O_{7}$) for high efficient solid oxide fuel cells applications. As (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$Mn $O_{3}$ cathode contact on YSZ substrate was sintering at 1250.deg. C the temperature that liquid phase sintering did not occur. It was possible to obtain proper cathode contacts with electrical conductivity of 150(S/cm) and porosity content of 30-40%.m) and porosity content of 30-40%.

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EFFECT OF CALCIUM HYDROXIDE ON BOND STRENGTH OF DENTIN BONDING SYSTEMS (수산화칼슘 적용에 따른 상아질 접착제의 접착강도 변화에 관한 연구)

  • Park, No-Hoon;Park, Sang-Hyuk;Choi, Gi-Woon;Park, Sang-Jin
    • Restorative Dentistry and Endodontics
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    • v.32 no.3
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    • pp.198-207
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    • 2007
  • The purpose of this study was to investigate the effect of calcium hydroxide on dentin bonding strength of various dentin bonding systems as a function of time in composite resin restoration. Dentin adhesives used in this study were Scotchbond Multipurpose, Single Bond, SE Bond and Prompt L-Pop. Flat dentin surfaces adjacent to pulp chamber were created, then $Ca(OH)_2$ and saline were mixed and applied on dentin surface of experimental group, then IRM was used to cover the mixture on dentin surface and the specimens were stored at $36.5^{\circ}C$ for experiment period (7 days, 30 days). After removing IRM and $Ca(OH)_2$, each dentin adhesives were treated on dentin surfaces. Composite resin (Z-250, 3M) was placed with S mm height and was light-cured for 20 seconds. After stored in distilled water for 24 hours, each dentin-composite bonded spicemen was embedded in epoxy resin and sectioned into $1.0\times1.0mm^2$ cross section composite-dentin beams. Specimen was mounted on zig of Universal testing machine and ${\mu}TBS$ test was performed. SEM analysis was performed to examine the fractured surfaces. The results suggested that applying calcium hydroxide did not show significant difference in dentin bonding strength.