• KSBB Journal
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• v.18 no.2
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• pp.79-89
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• 2003

This article contains an overview of acoustic wave devices, the theory and application of piezoelectric quartz crystal microbalances(PZ QCM), clinical analysis, gas phase detection, DNA biosensors, drug analysis, food microbial analysis and environmental analysis.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.8
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• pp.947-950
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• 1992

At-cut quartz crystal has been applied as chemical vapour sensors. The responses of quartz crystal at 9 MHz coated with phosphatidylglycerol(PG), phosphatidylinositol(PI), phosphatidylethanolamine(PE), phosphatidylserine(PS), and lipid A(LA) are determined for amyl acetate, acetoin, menthone and other organic gases which showed different affinities for each lipid. The identification of odorants depending on the species of lipid used for coating is discussed in terms of the normalized resonant frequency shift pattern.

• Journal of Applied Biological Chemistry
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• v.44 no.4
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• pp.163-166
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• 2001

Piezoelectric (PZ) crystal biosensor system was used to detect the DNA of food pathogenic Listeria monocytogenes. L. monocytogenes-specific DNA was multiplied via the polymerase chain reaction using LM1 oligonucleotide (5'-TTACGAATTAAAAAGGAGCG-3') and LM2 oligonucleotide (5'-TTAAATCAGCAGGGGTCTTT-3') as primers. DNA fragment of 161 bp, which was specific only for L. monocytogenes, was observed. To obtain a large amount of single-stranded DNA containing an SH group used for coupling to the gold electrode chemisorptively, LM1 oligonucleotide containing a mercaptohexyl group was utilized as a single strand PCR primer. The PCR product was immobilized onto the gold electrode of PZ crystal, and hybridization was monitored in quartz crystal microbalance (QCM) system by injecting the antisense single-stranded DNA of 161 nucleotides obtained via the single strand PCR using the unmodified LM2 primer. Approximately 70 Hz of frequency drop was observed in the QCM system in the case of two consecutive injections of $5{\mu}g$ of the antisense single-stranded DNA.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.543-546
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• 2001

So far, the design methods of quartz crystal resonator have been developed. Recently, as the electronic package and semiconductor modules become smaller, the need to minimize the sizes of crystal components grows larger. but Minimizing crystal plate sizes has limitations because its temperature-frequency characteristics is worse and unwanted resonances occur. so appropriate design of electrode size and crystal plates is necessary. In this palter, Two-dimensional governing equations for electroded piezoelectric crystal plates with general symmetry have been solved from deduced equations from three-dimensional equations of linear piezoelectricity in most cases. In practice, electroded piezoelectric crystal plates have three-dimensional geometry, so simplified 2-dimensional equations and 2-D modeling are insufficient for explaining its resonance modes and characteristics. So, three-dimensional FEM(finite element method) analysis is done and its effectiveness is verified from analyzing practical crystal resonator model.

• Journal of the Korean Ceramic Society
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• v.36 no.6
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• pp.640-645
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• 1999

Recently rapid progress of electronic and telecommunication technology requires the development of new piezoelectric materials and cellular communication is more and more used in various fields. Langasite(La3Ga5SiO14) is suitable for new piezoelectric properties. Langastie can be applied as communication devices due to intermediate piezoelectric properties which are similar to those of quartz and LiTaO3 in its acoustic characteristics. So in this study Langastie(La3Ga5SiO14) single crystal with 47 mm in diameter and 25mm in length were sucessfully grown by using self-designed Czochralski system. In addition optimum growth conditions for the piezoelectric applications throughout estimation of crystal quality and frequency characteristics were investigated.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.149-154
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• 2010

Top of the alumina body which is made according to plan has been printed using a screen printer equipment in order to print an electrode pattern. The electrode is connected with the quartz crystal oscillator of the piezoelectricity method which has a piezoelectric characteristic. The pressure contact department has been experimented using three type of the teflon. The teflon is good for pressure delivery vector but it is bad restitution. So we devised the structure which inserts the metal in the teflon. Bottom of the module is connected with the signal processing department which is planned in advance and then has investigated to characteristic. Therefore we have got the best output-voltage and frequency characteristic follows in the pressure.

• Transactions on Electrical and Electronic Materials
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• v.13 no.4
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• pp.171-176
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• 2012

As langasite $A_3BC_3D_2O_{14}$ compounds with piezoelectric properties exhibit no phase transition up to the melting point of 1,400-$1,500^{\circ}C$, many high temperature applications are expected for the SAW filter, temperature sensor, pressure sensor, and so on, based on the digital transformation of wider bandwidth and higher-bit rates. It has a larger electromechanical coupling factor compared to quartz and also nearly the same temperature stability as quartz. The $La_3Ga_5SiO_{14}$ (LGS) crystal with the $Ca_3Ga_2Ge_4O_{14}$-type crystal structure was synthesized and the crystal structure was analyzed by Mill et al. It is also an important feature that the growth of the single crystal is easy. In the case of three-element compounds such as $[R_3]_A[Ga]_B[Ga_3]_C[GaSi]_DO_{14}$ (R=La, Pr and Nd), the piezoelectric constant increases with the ionic radius of R. In this study, crystal structures of four-element compounds such as $[A_3]_A[B]_B[Ga_3]_C[Si_2]_DO_{14}$ (A = Ca or Sr, B = Ta or Nb) are analyzed by a single crystal X-ray diffraction, and the mechanism and properties of the piezoelectricity depending on the species of cation was clarified based on the crystal structure.

• Journal of the Korean Vacuum Society
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• v.21 no.6
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• pp.287-294
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• 2012

In the high vacuum condition of the space, outgassing from any assembly of satellite can contaminate satellites, especially second surface mirror and optical lens, it cause satellite to fail in own missions. Therefore, all unit shall be check for compatibility with vacuum using CVCM (Collected Volatile Condensable Material) and TML (Total Mass Loss) in advance. CVCM and TML of the PZT-5 piezoelectric ceramic vibrator has less than 0.1% and 1.0% respectively. Also, it has less than 500 $ng/cm^2/hr$ of Thermoelectric Quartz Crystal Microbalance for vacuum bake-out test using high temperature(more than $80^{\circ}C$) and high vacuum (less than $5.0{\times}10^{-3}$ Pa). Thus, piezoelectric ceramic vibrator may be employed in the vacuum environments. Finally, it can be confirmed that the characteristics change of the piezoelectric ceramic vibrator is less than 1% under vacuum environments.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.145-145
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• 1997

Recent progress of electric technology requires new piezoelectric crystals having superior properties such as zero temperature coefficients and large electromechanical coupling factors. We have developed a series of new leading chandidates, La$_3$Ga5SiO14(langasite, LGS), La3Nb0.5Ga5.5O14(LNG), La3Ta0.5O14(LTG), to satisfy those requirements. High quality LGS, LNG and LTG single crystals, with dimensions of 2 inches in diameter, were successfully grown by the Czochralski method at a pulling rate of 1mm/h. Since no variation of chemical composition was observed when whole melt in a crucible was crystallized, congruency of these compositions was confirmed. Physical constants such as elastic constants, dielectric constants and piezoelectric constants were measured. Filters and oscillators made of grown LGS, LNG and LTG single crystals showed superior properties such as three times wider passband than that of quartz, low insertion loss and easy processing, Langasite family crystals were shown to be superior materials to other known materials such as quartz, LiTaO$_3$, $\alpha$-AlPO$_4$ and Li$_2$B$_4$O7.

• Journal of Food Hygiene and Safety
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• v.13 no.3
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• pp.206-212
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• 1998

An improved antibody-coated sensor system based on quartz crystal microbalance was developed for the detection of Salmonella spp. An antibody against Salmonella common structural antigen was immobilized onto one gold electrode of the piezoelectric quartz crystal surface by various immobilization procedures. The best results in sensitivity and stability were obtained with the thin layers of protein A and 3,3'-dithiopropionimidate.2HCI(DTBP), a homobifunctional thiol-cleavable crosslinker. After the addition of a S. typhimurium suspension into a reaction cell with 0.1 M sodium phosphate buffer, pH 7.2, the resonant frequency owing to S. typhimurium adsorption decreased conspicuously. The antibody-immobilized crystals prepared by the gold-protein A complex formation and DTBP thiolation showed the frequency shifts of 80 and 283 Hz, respectively. The time required for maximum frequency shift was about 30~60 min. The antibody-coated crystal could be reused for 6~8 consecutive assays.