• Electrical & Electronic Materials
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• v.1 no.1
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• pp.44-53
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• 1988

In this study, PZT/PVDF composites with O-3 phase connectivity were prepared by hot pressing method, and the dielectric and piezoelectric properties as a function of PZT volume fraction were investigated. A modified cubic model was introduced to explain the influence of the PZT volume fraction on the experimentally determined dielectric constant. As A n=0.125, the measured dielectric constant values agreed with the calculated values. It was found that dielectric constant .xi.$_{33}$ and piezoelectric coefficient d$_{33}$ increased with indreasing PZT volume fraction, and hydrostatic piezoelectric figure of merit d/aub h/.g$_{h}$ was improved relative to that of the PZT single phase material.l.l.l.

• International Journal of Oral Biology
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• v.45 no.4
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• pp.211-217
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• 2020

Molecular mimicry is the most common mechanism that breaches self-tolerance. We previously identified autoantibodies to aquaporin-5 (AQP5) in the sera of patients with Sjögren's syndrome and found that the aquaporin of Prevotella melaninogenica (PmAqp), an oral commensal, is highly homologous to human AQP5. This study aimed to test whether PmAqp can induce anti-AQP5 autoantibodies via molecular mimicry. From the amino acid sequence of PmAqp, an immunizing peptide; i.e., PmE-L, was designed, which contained both the B cell epitope "E" and T cell epitope. C57BL/6 and BALB/c mice were subcutaneously immunized with linear or cyclic forms of PmE-L emulsified in incomplete Freund's adjuvant. The concentrations of the antibodies in sera were measured using enzyme-linked immunosorbent assays. Both linear and cyclic PmE-L induced high levels of antibodies against not only the immunized peptides but also autoantibodies against AQP5E and antibodies against PmE, a Pm homolog of AQP5E. In C57BL/6 mice; however, the cyclic form of PmE-L was more efficient than the linear form in inducing autoantibodies against AQP5E that contained a cyclic epitope. The levels of anti-PmE antibodies and anti-AQP5E autoantibodies showed a strong positive correlation (r = 0.95, p < 0.0005), suggesting molecular mimicry. Collectively, the mice produced anti-AQP5E autoantibodies in response to a PmAqp-derived peptide. This model proved to be useful for studying the mechanisms of autoantibody production by molecular mimicry.

• Journal of Microbiology and Biotechnology
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• v.26 no.11
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• pp.1918-1923
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• 2016

Two baicalein derivatives, baicalin and oroxylin A, were synthesized in this study. These derivatives exhibit diverse biological activities, such as anxiolytic and anticancer activities as well as memory enhancement. In order to synthesize baicalin from aglycon baicalein using Escherichia coli, we utilized a glycosyltransferase that regioselectively transfers glucuronic acid from UDP-glucuronic acid to the 7-hydroxy group of baicalein. To increase baicalin productivity, an araA deletion E. coli mutant, which accumulates UDP-glucuronic acid, was used, and ugd, which converts UDP-glucose to UDP-glucuronic acid, was overexpressed. Using these strategies, approximately $720.3{\mu}M$ baicalin was synthesized from $1,000{\mu}M$ baicalein. Oroxylin A was then synthesized from baicalein. Two O-methyltransferases (OMTs), ROMT-15 and POMT-9, were tested to examine the production of oroxylin A from baicalein. E. coli harboring ROMT-15 and E. coli harboring POMT-9 produced reaction products that had different retention times, indicating that they are methylated at different positions; the structure of the reaction product from POMT-9 was consistent with oroxylin A, whereas that from ROMT-15 was 7-O-methyl baicalein. Using E. coli harboring POMT-9, approximately 50.3 mg/l of oroxylin A ($177{\mu}M$) was synthesized from 54 mg/l baicalein ($200{\mu}M$).

• Electrical & Electronic Materials
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• v.8 no.6
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• pp.787-794
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• 1995

To improvement the magnetic and frequency properties of YIG(Yttrium-Iron Garnet) in microwave region, it is investigated that the effect of $Al^{3+}$ ions on magnetic and frequency characteristics of YIG, using samples of basic YIG composition( $Y_{3}$F $e_{5}$ $O_{l2}$) added with A1$_{2}$ $O_{3}$ from 0 to 2.5 [mol%]. The measurment is conducted mainly for the structural properties and magnetical properties. The structural properties is measured using SEM(Scanning Electro Microscope), EDX(Energy-dispersive X-ray spectrometer) and XRD(X-ray diffraction equipment). The magnetical properties is measured with B-H curve tracer and impedance analyzer. As a result, it is confin-ned that the effect of eddy current loss is minimized while maintaining high saturation flux density of YIG, when YIG is added with 0.5 [mol%] of A1$_{2}$ $O_{3}$.>.>.

• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.174-180
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• 2013

This study investigated the microbiological contamination of tomato in cultivation and distribution stage. Growth of Escherichia coli O157:H7 and Listeria monocytogens examined in tomato extracts (0.1, 1.0, and 10.0%) and incubation temperatures (5, 15, 25, and $35^{\circ}C$). In cultivation stage of tomato, total aerobic bacteria were 7.77 log CFU/g in gloves of APC (Agricultural Products Processing Center) worker and Bacillus cereus were 0.33 log CFU/g at nutrient tank, respectively. And Staphylococcus aureus, Salmonella spp., were not detected. After APC stage, total aerobic bacteria were significantly higher compared with before-APC stage. Among of general, pesticide-free and organic produce in tomato were no significant difference in microbial contamination. Coliforms of tomato in small vinyl package were significantly higher when compared to tomato in whole boxes package. There was no significant difference in bacteria count between unwashed tomato and washed tomato using tap water for one minute. The growth of E. coli O157:H7 and L. monocytogens in tomato extracts were decreased significantly as the concentration increased, and the microbial population was reached the lowest point during storage in 10% tomato extracts concentration for 72h at $5^{\circ}C$. However, the population of E. coli O157:H7 and L. monocytogens were gradually increased at 7.33~8.51 and 7.73~8.60 log CFU/ml during storage at $15{\sim}35^{\circ}C$ for 72h, respectively.

• Korean Journal of Materials Research
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• v.7 no.2
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• pp.152-156
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• 1997

In this paper, I meritioned ,I study on thc rnechanochernic;~l effec ts of grountl iljckite To investigate the mechanochemical effects of ground tlickite 1,y planet,~r\- mill. a structul-ill i~nalvsis of dickite prepared with different grinding time has been made 11y X-ray diffraction and ilifierenti,~l tl~i.~-ni;~i analysis. 'l'he $SiO_{4}$ hecira was unchanged bl- milling and remained ;is the local ordering unit s t t - ~ c ~ u ~ - c ~ s in the ground dickitc samples I ) v analyzing the radial distribution function. On the other hand, with an increi~se of the grinding time a decrease of coordination number and atomic distance bet\vccn aluminum and oxygen hi1c.r l~een octurreil, and Li~~antitativcl\. coniirrned them This result corresponded to the local c,hange around aliimi~iuni I>V tliftercntii~l t1ii:rm;il ani~lysis. Therefore, the mechanochemical phenomina of ground tiickite werc3 h e to the local c~l~mge around aluminum \IT. the prolonged grinding.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.128-131
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• 1997

기본 조성식 M $n_{1-x}$/F $e_{2+x}$/ $O_4$(이하 Mg계), M $n_{1-x}$/F $e_{2+x}$/ $O_4$(이하 Mg계)의 식에서 x를 0.0,0.025,0.1,0.2로 변화시키고, 하소온도 80$0^{\circ}C$, 소결은도를 l10$0^{\circ}C$~12$50^{\circ}C$로 $50^{\circ}C$간격으로 변화 시켰을 때와 Mn계와 Mg계를 1:1로 흔합하였을 때, F $e_2$ $O_3$의 과잉 양이 증가할수록 비저항은 감소하였고, 저항온도계수 $\alpha$는 밀도와 비례하는 관계를 나타내었으며, B정수는 4600(K)에서 10500(K)의 범위를 나타내었다. 본 조성의 실험으로써 Mn-Ni-Co계 서미스터의 대체가 가능함을 확인할 수 있었다.있었다.

• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1078-1084
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• 2003

In order to develop a new type of nonlinear optical materials or photocatlaysts, Na$_2$O-Nb$_2$ $O_{5}$-Te $O_2$ glasses were prepared using conventional melt quenching method, and the crystallization behaviors and optical properties of these glasses was investigated. The optical and physical properties for Na$_2$O-Nb$_2$ $O_{5}$-Te $O_2$ glasses are: refractive index, n=2.04$\pm$0.04; density, p (g/㎤)=4.87$\pm$0.58; optical energy band of the transmission cut-off wavelength, E$_{0}$ (eV)=3.14$\pm$0.04. The transparent glass ceramics consisting of the nanocrysatls were obtained when the Na$_2$O-Nb$_2$ $O_{5}$-Te $O_2$ glass was first heat-treated at 3$50^{\circ}C$ for 1 h and than at 40$0^{\circ}C$ for 1 h. A cubic crystalline phase consisting of the nano-crysatls transforms into a stable phase at temperature above 47$0^{\circ}C$ for 1 h.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.728-736
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• 2001

Effects of packaging material and oxygen absorbant on physical and chemical properties of Yukwu were studied during storage to develop packaging conditions. The packaging materials used were PET/EVOH $(16\;{\mu}m)/PL$ : P1 and PET/EVOH $(24\;{\mu}m)/PL$ : P2 with or without oxygen absorbent (E1A : P1 and E2A : P2 for w/ $O_2$, absorbent, E1EA : P1 and E2EA : P2 for w/o $O_2$, absorbent). Color values for Yukwu indicated that L values of E1A, E1EA, E2A and E2EA were decreased during storage while those b values were increased. Hardness and chewiness of Yukwa were generally decreased, however those of E1A and E1EA were rather increased after 6 weeks of storage. Acid value of E2A had maintained less than 2.0 during 12 weeks of storage. E1A, E2A had the below of 20 in peroxide during 12 weeks. Aroma data by using electronic nose showed that there was no difference after 6 week storage time in different packaging materials. Sensory evaluation (Yukwa odor and rancid odor) showed very similar results with electronic nose one. E2A had the highest value of overall acceptability for sensory evaluation. Hardness and cheweness in physical measurement results had the highest correlation with hardness, crispness, overall-acceptability in sensory evaluation results.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.41-46
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• 2022

This study is a Ku-band array antenna for the manufacture of low-orbit satellite communication terminals, designed to have miniaturization, high gain, and wide beam width. The transmission of low-orbit satellite communication has a right-rotating circularly polarized wave, and the reception has a left-rotating circularly polarized wave. The 4×8 array antenna was separated for transmission and reception, and it was combined with the RF circuit part of the transmitter and receiver, and was terminated in the form of a waveguide for RF signal impedance matching in the form of a transition from the microstrip line to the waveguide. The 30° beam width of the receiver maximum gain of 19 dBi and the 29° beam width of the transmitter maximum gain of 18 dBi are shown. Through this antenna configuration, the system was configured to suit the low-orbit satellite transmission/reception characteristics.