• Preventive Nutrition and Food Science
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• v.5 no.3
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• pp.153-159
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• 2000

A 4.4 kb DNA fragment encompassing lacA (galactoside acetyltransferase) and lacZ($\beta$-galactosidase) genes from Lactococus lactis ssp. lactis ATCC 7962 (L. lactis 7962) was introduced ito a Lac strain, Lactococcus lactis ssp. lactis MG1363 (L. lactis MG1363) by using a lactococcal expression vector, pMG36e and expression level of lacZ was examined. Growth rates and $\beta$-galactosidase ($\beta$-gal) activities of MG1363 cells carrying recombinant plasmid, pMLZ3, on M17 broth containing different carbon sources (1%, w/v) were examined. Contrary to the expectations, MG1363 [pMLZ3] grown on lactose showed the lowest enzyme activity (17 units) and cells grown on galactose had the highest $\beta$-gal activity (41 units). Cells grown on glucose had intermediate activity (33 units). These activities are about one tenth of the values observed in L. lactis 7962 where lacZ is present as a single-copy gene in the chromosome. When the cellular concentrations of lacZ transcript were examined using slot blot hybridization, it was found that MG1363[pMLZ3] produced sufficient amounts of transcript. These results indicate that either proteolytic degradation of $\beta$-gal or other regulatory mechanism prevent the translation or accumulation of $\beta$-gal in L. lactis MG1363 cells. In regard to regulation, the presence of the ccpA gene in L. lactis MG1363 was confirmed by Southern blot.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.201-205
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• 1999

The effects of growth temperature and a carbon source on the expression of $\beta$-galactosidase gene of Lactococcus lactis ssp. lactis ATCC 7962 (L. lactis 7962) were investigated. At $25^{\circ}C$, L. lactis 7962 had a higher $\beta$-galactosidase activity than cells grown at $30^{\circ}C$ or $37^{\circ}C$, although cells grew most quickly at $37^{\circ}C$ The highest $\beta$-galactosidase activity was observed in cells grown in M17 with lactose (l %) followed by cells grown in a galactose (1 %) medium. L. lactis 7962 exhibited the minimum $\beta$-galactosidase activity in glucose media, indicating catabolite repression. When the cellular levels of $\beta$-galactosidase mRNA were examined using slot blot hybridization, no significant differences were observed between cells grown at $25^{\circ}C$ and cells at $30^{\circ}C$ or $37^{\circ}C$ in the same media. This suggests that the quantity of $\beta$-galactosidase mRNA may not be the reason for the higher $\beta$-galactosidase activities of L. lactis 7962 at $25^{\circ}C$ The level of ccpA (Catabolite Control Protein) transcript remained almost constant during the exponential growth phase irrespective of a carbon sourse.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.617-624
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• 2009

In this paper, an electromagnetic analysis methodology using reaction theorem based on reciprocity theorem is presented for the aspheric ogival radome applied to a missile and/or airborne radar. The presented analysis methodology is verified using actual measured data. The type of antenna assumed to develope the methodology is a waveguide slot array antenna, and has the structure of 2 axes monopulse of "X" type. The shape of radome is assumed as Von Karman and the ratio of length to base diameter(L/D) is assumed to be 2:1. The electrical characteristics of the radome are measured using radome measurement system and the results are compared to the values estimated using the presented analysis methodology. It is found that the comparison shows good agreement. It is expected that the presented methodology can be applied for the development of missile and airborne radome.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3B
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• pp.138-143
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• 2005

This paper aims to optimize an access probe algorithm for the CDMA 2000 system. The incremental value of PWR_STEP increases as NUM_STEP as 1dBm±0.2 for access probe of the area with good receiving sensitivity when the mobile station transmits via access channel and does not receive any ACK message. However, for the area with weak receiving sensitivity, according to the algorithm of open-loop power control, the transmitting power amplifier becomes saturated and PWR_STEP incremental value keeps performing access probe to 0dBm±0.2. Therefore interference and battery consumption increases according to the transmission of the mobile station. We have optimized the access probe algorithm according to the receiving sensitivity. We transmit the incremental value of access probe power, with delaying as much RT slot value as indicated by IS-95C standard in case of good receiving sensitivity and with delaying RT+l slot value in case of weak receiving sensitivity. Simulation results showed that the proposed algorithm contributes to decrease of the interference and battery consumption according to the transmitting power of the mobile station and improves the call duration.

• Journal of Animal Environmental Science
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• v.14 no.1
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• pp.39-46
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• 2008

Experiments were carried out to evaluate the air speed distribution of an enclosed growing-finishing pig house in summer and winter. The data taken by experiments were compared to validate with the calculated air speeds by a commercial CFD code, FLUENT. Air basically enters into the house through Baffled slot Inlet and leaves through a exhaust fan attached on the Exhaust fan in exiting wall of the house. Air speeds were measured as $2{\sim}2.5m/s$ at the two side slot in winter and 0.8 m/s in summer. The validation showed that a CFD simulation is one of feasible methods to predict airspeed distribution in the growing-finishing pig house.

• Imaging Science in Dentistry
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• v.51 no.4
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• pp.413-419
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• 2021

Purpose: The aim of this in vitro study was to assess the role of bandwidth on the area of magnetic resonance imaging (MRI) artifacts caused by orthodontic appliances composed of different alloys, using different pulse sequences in 1.5 T and 3.0 T magnetic fields. Materials and Methods: Different phantoms containing orthodontic brackets (ceramic, ceramic bracket with a stainless-steel slot, and stainless steel) were immersed in agar gel and imaged in 1.5 T and 3.0 T MRI scanners. Pairs of gradient-echo (GE), spin-echo (SE), and ultrashort echo time (UTE) pulse sequences were used differing in bandwidth only. The area of artifacts from orthodontic devices was automatically estimated from pixel value thresholds within a region of interest (ROI). Mean values for similar pulse sequences differing in bandwidth were compared at 1.5 T and 3.0 T using analysis of variance. Results: The comparison of groups revealed a significant inverse association between bandwidth values and artifact areas of the stainless-steel bracket and the self-ligating ceramic bracket with a stainless-steel slot(P<0.05). The areas of artifacts from the ceramic bracket were the smallest, but were not reduced significantly in pulse sequences with higher bandwidth values(P<0.05). Significant differences were also observed between 1.5 T and 3.0 T MRI using SE and UTE, but not using GE 2-dimensional or 3-dimensional pulse sequences. Conclusion: Higher receiver bandwidth might be indicated to prevent artifacts from orthodontic appliances in 1.5 T and 3.0 T MRI using SE and UTE pulse sequences.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.48-56
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• 2011

A Possibility of combustion instability on longitudinal mode has a high level at large scale of L/D. Solid propellant has a metal particle and a grain of control to pressure oscillation. Solid rocket motor in slotted-tube grain controls pressure oscillation of longitudinal mode. Slotted-tube grain restrains longitudinal 1st pressure oscillation. But cavity volume of aft. insulation ablation amplifies 2nd pressure o scillation by vortext shedding. A study has suppressed combustion instability and vortex shedding by modified 4 slotted tube solid rocket motor design.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.27-36
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• 2001

In this paper, micromachined millimeter-wave cavity resonators ar presented. One-port and two-port cavity resonators at Ka-band are designed using 3D design software, HP $HFSS^{TM}$ ver. 5.5 Cavity resonators are fabricated on Si substrate, which is etched down for the cavity, bonded with a Quartz wafer in which metal patterns for the feeding line coupling slot are formed. One-port resonator shows the resonant frequency of 39.34 GHz, the return loss of 14.5 dB, and the loaded $Q(Q_{L})$ of 150. Two-port cavity resonator shows the resonant frequency of 39 GHz, the insertion and return losses of 4.6dB and 19,9dB, the loaded($Q_{L}$) and unloaded $Q(Q_{U})$) of 44.3 and 107, respectively.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.345-348
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• 2008

Metallic bipolar plate for molten carbonate fuel cell(MCFC) is composed of the shielded slot plate and the center plate. Among these, the center plate plays an important role in gas sealing. Therefore, manufacturing of the center plate is considered one of the key issues in MCFC. The center plate is manufactured by bending process. In bending process, springback and recoiling are two main problems. The aim of this article is to optimize the bending process of the center plate regardless of springback and recoiling. To achieve this goal, we proposed the punch having step to reduce springback and recoiling. Using finite element method and $L_9$ orthogonal array, we determined the main factors in the center plate bending process. And we found the optimal bending process condition for the MCFC center plate.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.188-194
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• 2015

This paper proposes a generalized regression neural network (GRNN) based algorithm for data interpolation and design optimization of brushless dc (BLDC) motor. The procedure makes use of magnet length, stator slot opening and air gap length as design variables. Cogging torque and average torque are treated as performance indices. The optimal design necessitates mitigating the cogging torque and maximizing the average torque by varying design variables. The data set for interpolation and ensuing design optimisation using GRNN is obtained by modeling a standard BLDC motor using finite element analysis (FEA) tool MagNet 7.1.1. The performance indices of the standard motor obtained using FEA are validated with an experimental model and an analytical method. The optimal design is authenticated using particle swarm optimization (PSO) algorithm and the performance indices of the optimal design obtained using GRNN is validated using FEA. The results indicate the suitability of GRNN as an interpolation and design optimization tool for a BLDC motor.