• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.973-978
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• 2001

The bacterial flagellar motor is a molecular machine that couples proton or sodium influx to force generation, mostly for driving rotation of the helical flagellar filament. In this study, we cloned a gene (motX) encoding a component of the sodium-driven flagellar motor from Vibrio fluvialis. The nucleotide sequence of the motX gene, composed of 633 bp and 211 amino acid residues, was determined. Overexpression of the motX gene in Escherichia coli using a strong promoter induced growth inhibition and cell lysis. The lethal effect of E. coli was suppressed by adding amiloride, as a potent inhibitor for the sodium channel. Electron microscopic observation of the expressed protein indicated that MotX protein induced by isopropyl ${\beta}$-D-thiogalactopyranoside caused the lysis of host cell.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.451-453
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• 2002

The rotation of the flagellar motor is powered by the electrochemical gradient of specific ions across the cytoplasmic membrane. Recently, the gents of the Na'-driven motor have been cloned from marine bacterium of Vibrio sp. and some of the motor proteins have been purified and characterized. Also, motx gene encoding a channel component of the sodium type flagellar motor was identified from Vibrio Huuiaiis (KTCC 2473). The amino acid sequence of MotX protein from V, Huvialis shared 90, 85, $85\%$ identity with V, cholerae, V. alginolyticus, V parahaemolyticus, respectively. We have studied the localization of the expressed MotX protein in Escherichia coli by immune-gold labeling of ultra-thin frozen section. Our observation of the expressed protein indicated that MotX protein could be existed as attachment to inner membrane in E. coli.

• Electrical & Electronic Materials
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• v.9 no.8
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• pp.836-850
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• 1996

In this study, we have analyzed structural analysis and measured ferroelectric characteristics of PZT thin films prepared by sol gel process with different sintering conditions and different Zr/Ti mot%. When the Zr mot% of PZT thin film was increased, it was found that the remanent. polarization and coercive field were decreased and increased, respectively. Also, the maxium dielectric constant of PZT(50/50) thin film was 786.8. We got double hysteresis(anti-fcrroelectric) curve from PbZrO$_{3}$ thin film. As heating rate goes up, pyrochlore phase of PZT thin film was decreased and dielectric and ferroelectric characteristics were improved. As a result of variation of sintering temperature and time 500.deg. C-800.deg. C and 5 sec.-8 hours, respectively, we got optimal sintering temperature and time. The optimium sintering temperature and time of conventional furnace method and rapid thermal processing method were 650.deg. C-700.deg. C for 30-60 minutes and 700.deg. C/20 seconds-2 minutes, respectively.

• Journal of Chest Surgery
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• v.15 no.2
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• pp.238-242
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• 1982

The incidence of annuloaortic ectasia has known rare, and approximately 5-10% of aortic regurgitation. The patient was 44 years old male who complained exertional dyspnea and left anterior chest pain. He had done Lt. side 2 stage thoracoplasty for pulmonary tuberculosis about 20 years ago at Dept.of Chest surgery of National Medical Center. At that time, there was no abnormal findings in cardiovascular system. The preoperative aortic cineangiogram showed pear shaped dilatation [7.3 cm x 6.8 cm] of aortic mot with aortic valve regurgitation but left ventricular ejection function was fair. Preop. ventilatory function test showed mixed type pulmonary insufficiency. Recently, we corrected surgically, by AVR with Carpentier-Edwards Bioprosthesis [29mm] & supracoronary Woven Dacron graft [29mm x 5cm] replacement, with good clinical result for follow up 6 months.

• The KIPS Transactions:PartA
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• v.12A no.5 s.95
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• pp.413-420
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• 2005

The Newton-Raphson iterative algorithm for finding a floating point reciprocal square mot calculates it by performing a fixed number of multiplications. In this paper, a variable latency Newton-Raphson's reciprocal square root algorithm is proposed that performs multiplications a variable number of times until the error becomes smaller than a given value. To find the rediprocal square root of a floating point number F, the algorithm repeats the following operations: '$X_{i+1}=\frac{{X_i}(3-e_r-{FX_i}^2)}{2}$, $i\in{0,1,2,{\ldots}n-1}$' with the initial value is '$X_0=\frac{1}{\sqrt{F}}{\pm}e_0$'. The bits to the right of p fractional bits in intermediate multiplication results are truncated and this truncation error is less than '$e_r=2^{-p}$'. The value of p is 28 for the single precision floating point, and 58 for the double precision floating point. Let '$X_i=\frac{1}{\sqrt{F}}{\pm}e_i$, there is '$X_{i+1}=\frac{1}{\sqrt{F}}-e_{i+1}$, where '$e_{i+1}{<}\frac{3{\sqrt{F}}{{e_i}^2}}{2}{\mp}\frac{{Fe_i}^3}{2}+2e_r$'. If '$|\frac{\sqrt{3-e_r-{FX_i}^2}}{2}-1|<2^{\frac{\sqrt{-p}{2}}}$' is true, '$e_{i+1}<8e_r$' is less than the smallest number which is representable by floating point number. So, $X_{i+1}$ is approximate to '$\frac{1}{\sqrt{F}}$. Since the number of multiplications performed by the proposed algorithm is dependent on the input values, the average number of multiplications Per an operation is derived from many reciprocal square root tables ($X_0=\frac{1}{\sqrt{F}}{\pm}e_0$) with varying sizes. The superiority of this algorithm is proved by comparing this average number with the fixed number of multiplications of the conventional algorithm. Since the proposed algorithm only performs the multiplications until the error gets smaller than a given value, it can be used to improve the performance of a reciprocal square root unit. Also, it can be used to construct optimized approximate reciprocal square root tables. The results of this paper can be applied to many areas that utilize floating point numbers, such as digital signal processing, computer graphics, multimedia, scientific computing, etc.

• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.95-108
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• 1984

Even though the tarnishing and corrosion problems characteristic with dental silver-palladium alloy are not yet fully solved, it is recently widely used because of its low cost. However the effects of major alloying elements on the various properties of this system are not fully understood. The object of this research is to clarify the effects of In and Zn additives on the corrosion and tarnishing resistances and precipitation hardening behavior of this sytem, using electrodynamic polarization, immersion, and Vicker's microhardness test and X-ray diffraction and electron probe micro analysis methods. The obtained results were as follows: I. As indium content is increased, both the corrosion resistance in Cl-solution and microhardness are also increased while the tarnishing resistance is decreased. 2. As Zinc content is increased, the corrosion resistance is decreased, but tarnishing resistance is increased 3. At 70Ag-25Pd-2.5Zn-2.5In composition, the precipitation harding behavior was mot significant. The optimum aging temperature was $450^{\circ}C$ and the time was 2 hrs. The resulting specimen of this work carried 180VHN. 4. Under the heat treatment, the changes in the mechanical property are due to the changes in the shape and composition of dendrite matrix, namely, it is because of the precipitation hardening behavior which has been proved by electron probe micro analysis and optical microscopic finding.

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.253-261
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• 2002

This study was carried out to investigate the semen characteristic, motility and viability and sperm motion characteristic by CASA test for establishing the Jindo-dog's semen freezing system. The results obtained are as follow: 1. The semen was collected 63 times. Average volume of semen, concentration of sperm, total number of sperm, progressive motility and viability were 3.8 $m\ell$ 145.6$\times$10$^{6}$ cells/$m\ell$, 396.2 x10$^{8}$ cells, 79.7% and 89.5%, respectively. Also, Fawn (Yellow) Jindo-dog comparing with White Jindo-dog showed better concentration of sperm, total number of sperm, progressive motility and viability. Among all dogs, the results of No. 2 Fawn Jindo-dog were the best. 2. The average progressive motility and viability of semen from 46 times were 73.5%, 82.3% before freezing and 51.1%, 64.9% after freezing. So, the freezing of semen has affected the progressive motility and viability. The progressive motility and viability of Fawn Jindo-dog's semen, before and after freezing, were better than White Jindo-dog. And No. 2 Fawn Jindo-dog showed the best results and showed significantly different among all dogs (P<0.05). 3. The 44 times-tested .esults by CASA system were as follow; MOT (motility) 65.6%. PROG (progressive motility) 54.8%, VAP (average path velocity) 75.3 ${\mu}{\textrm}{m}$/sec, VCL (curve linear velocity) 90.0 ${\mu}{\textrm}{m}$/sec, VSL (straight-line velocity) 69.4 ${\mu}{\textrm}{m}$/sec and ALH (amplitude of lateral head displacement) 4.4 ${\mu}{\textrm}{m}$. Although the motion characteristic of frozen semen were not significantly different between White and Fawn Jindo-dog, No. 2 Fawn Jindo-dog showed the best results and was significantly different among all dogs (P<0.05). 4. The success rate of frozen semen production between White and Fawn Jindo-dog were 43% (13/28), 94% (33/35), respectively, and the total success rate was 73% (46/63). The freezing-ability of Fawn Jindo-dog's semen was better than the other. Conclusively, the present results indicated that the characteristic and motility of Jindo-dog') semen were suitable for processing frozen semen, artificial insemination and mass production system. Also, the selection of suitable dog-breed was so important because the characteristic and freezing-ability of semen were significantly different between White and Fawn Jindo-dogs and among all individual dogs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.143-148
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• 2001

PbWO$_4$ can be densified at 85$0^{\circ}C$ and it shows fairy good microwave dielectric properties; dielectric constant($\varepsilon$$_{r}$) of 21.5, quality factor(Q $\times$f$_{0}$) of 37,224 GHz, and temperature coefficient of resonant frequency($\tau$/suf f/) of -31ppm/$^{\circ}C$. Due to its low sintering temperature, PbWO$_4$ can be used as a multilayered chip component at microwave frequency with high electrical performance by using high conductive electrode metals such as Ag and Cu. However, in order to use this material for microwave communication devices, the $\tau$$_{f}$ of PbWO$_4$ must be stabilized to near zero with high Q$\times$f$_{0}$. In present study, PbWO$_4$ was modified by adding TiO$_2$, B$_2$O$_3$, and CuO in order to improve the microwave dielectric properties without increasing the sintering temperature. The addition of TiO$_2$ increased the $\tau$$_{f}$ and $\varepsilon$$_{r}$, due to its high rr(200ppm/$^{\circ}C$) and $\varepsilon$$_{r}$(100). However, the addition of TiO$_2$ reduced the Q$\times$f$_{0}$ value. When the mot ratio of PbWO$_4$ and TiO$_2$ was 0.913:7.087, near zero $\tau$$_{f}$(0.2ppm/$^{\circ}C$) was obtaibed with $\varepsilon$$_{r}$=22.3, and Q$\times$f/$_{0}$=21,443GHz. With this composition, various amount of B$_2$O$_3$ and CuO were added in order to improve the quality factor. The addition, of B$_2$O$_3$ decreased the $\varepsilon$$_{r}$. However, increased Q$\times$f$_{0}$ and $\tau$$_{f}$. When 2.5 wt% of B$_2$O$_3$ was added to the 0.913PbWO$_4$-0.087TiO$_2$ ceramic, $\tau$$_{f}$ =8.2, $\varepsilon$$_{r}$=20.3, Q$\times$f$_{0}$=54784 GHz. When CuO added to the 0.913PbWO$_4$-0.087TiO$_2$ ceramic, $\tau$$_{f}$ was continuously decreased. And $\varepsilon$$_{r}$ . and Q$\times$f$_{0}$ were increased up to 1.0 wt% then decreased. At 0.1 wt% of CuO addition, the 0.913PbWO$_4$-7.087Ti0$_2$ Ceramic Showed $\varepsilon$$_{r}$=23.5, $\tau$$_{f}$=4.4ppm/$^{\circ}C$, and Q$\times$f$_{0}$=32,932 GHz.> 0/=32,932 GHz.X>=32,932 GHz.> 0/=32,932 GHz.