• 한국초전도학회:학술대회논문집
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• v.10
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• pp.151-154
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• 2000

We have developed a YBCO SQUID gradiometer system for the measurement of a very weak magnetic field in an unshielded environment. The system consists of a SQUID gradiometer sensor, low noise pre-amp, and FLL(fluxlocked loop) control electronics. The gradiometer sensors have been fabricated on STO bicrystal substrates, and exhibit a magnetic noise of 300 fT/${\surd}$ Hz/cm at 100 Hz. The overall magnetic field noise of the SQUID gradiometer system was about 10 pT/${\surd}$ Hz/cm at 10 Hz without any magnetic shield. The system demonstrated a high stability for a long time, and real-time measurement resolution ${\le}$ 100 pT/cm in the unshielded environments.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.43.3-44
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• 2017

We report the operational highlights of KMTNet in the point of observing rate, image pre-processing and data reduction, observing run for each science program, and scientific publications performed in 2016. Major system upgrade has been conducted in the CCD camera and the wide field telescope optics: the post amp and readout electronics of the 18k Mosaic CCD camera at Siding Spring Observatory site has been fine tuned and the protected silver coat of the primary mirror has been replaced with the bare aluminium coat due to the degradation of reflectivity of the primary mirror surface. A plan of KMTNet observation system improvement for 2017 will be introduced in this talk.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.307-307
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• 2010

ICRF 또는 NB 시스템에 의해 가열된 고에너지 이온들을 측정하는 것은 핵융합 플라즈마에서 중요한 과제 중의 하나이다. 특히 ICRF를 이용한 D(H) 플라즈마의 H minority의 가열은 H의 분율에 따라 가열의 정도가 달라지고 이 결과는 이온의 고에너지 측정을 통해서 확인할 수 있으므로 정확한 고속 이온의 측정은 매우 중요하다. 본 연구에서는 고속 이온을 전하 교환된 중성입자로부터 측정하는 중성입자 검출기를 개발하였다. Si 광다이오드인 AXUV3ELA를 기반으로 50-300 keV 범위의 고에너지 H 및 D 이온을 측정할 수 있는 소형의 중성입자 검출기(Compact Neutral Particle Analyzer : CNPA)가 설계 제작되었다. 검출된 신호는 Pre-amp와 shaping amplifier를 통해 증폭되고 shaping 되며 마지막으로 다중채널 분석기(Multi Channel Analyzer : MCA)를 통해서 계수된다. 본 발표에서는 NPA의 구체적인 설계 특성과 함께 Am-241 gamma ray 선원을 이용한 NPA의 시험 및 보정결과를 보고할 예정이다.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.195-198
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• 2001

We developed the portable blood analysis system, which can be measured pH of the blood. This system is composed to electronic circuit, mechanism, and system software. Electronic circuit is composed to the sensor, pre-amp part, temperature regulation part, fluid sensing part, A/D(analog to digital) conversion part, main and peripheral device processing part. And the mechanism is composed to the flow cell and the liquid flow part. The liquid flow part is consisted of blood and washing control system under the control of the 6-channel solenoid valve and syringe rump. The system software is composed to measurement program, calibration program, washing and diagnostic program. The program of each routine is designed as sequential process for an efficiency. And the portable pH analysis system used two-point calibration method using the two types of corrective liquid. As a result, we obtained the calibration curve and calculated the value of pH. For verifying the system, we confirmed the output voltage of the sensor, and estimated reappearance of system using the standard liquid.

• Journal of the Korean Institute of Navigation
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• v.20 no.2
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• pp.97-107
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• 1996

The method of Electromagnetic Wave Immunity Test is continuously endeavored by IEC and CISPR as international unification, but it has not been established yet. The main reason is why it is difficult to obtain the measurement method and normalization of threshold to find out the complicated parameters for Electromagnetic Wave immunity Test. So far, thus, the Electromagnetic Wave Immunity Test is carried out case by case as the electromagnetic environment, which is set up Electromagnetic Wave Immunity Test. This study has developed an algorithm and measurement software suitable for IEC1000-4 Regulations, where a ready-made Amplifier, and Signal Generator have been used and an interconnecting Interface Board has been constructed for connecting with the other apparatuses, i.e., RF Switch, Power Meter, Field Sensor, Pre-Amp., etc. Therefore, we have achieved the aim to develop an automated software using OOP method and the measurement system.

• The Plant Pathology Journal
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• v.34 no.6
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• pp.470-479
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• 2018

The rice blast pathogen Magnaporthe oryzae is a global threat to rice production. Here we characterized RHO2 gene (MGG_02457) that belongs to the Rho GTPase family, using a deletion mutant. This mutant ${\Delta}Morho2$ exhibited no defects in conidiation and germination but developed only 6% of appressoria in response to a hydrophobic surface when compared to the wild-type progenitor. This result indicates that MoRHO2 plays a role in appressorium development. Furthermore, exogenous cAMP treatment on the mutant led to appressoria that exhibited abnormal morphology on both hydrophobic and hydrophilic surfaces. These outcomes suggested the involvement of MoRHO2 in cAMP-mediated appressorium development. ${\Delta}Morho2$ mutation also delayed the development of appressorium-like structures (ALS) at hyphal tips on hydrophobic surface, which were also abnormally shaped. These results suggested that MoRHO2 is involved in morphological development of appressoria and ALS from conidia and hyphae, respectively. As expected, ${\Delta}Morho2$ mutant was defective in plant penetration, but was still able to cause lesions, albeit at a reduced rate on wounded plants. These results implied that MoRHO2 plays a role in M. oryzae virulence as well.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6432-6439
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• 2014

The NAUT (Non-contact Air coupled Ultrasonic Testing) technique is one of the ultrasonic testing methods that enables non-contact ultrasonic testing by compensating for the energy loss caused by the difference in acoustic impedance of air with an ultrasonic pulser receiver, PRE-AMP and high-sensitivity transducer. As the NAUT is performed in a state of steady ultrasonic transmission and reception, testing can be performed on materials of high or low temperatures or specimens with a rough surface or narrow part, which could not have been tested using the conventional contact-type testing technique. For this study, the internal defects of spot weld, which are often applied to auto parts, and CFRP parts, were tested to determine if it is practical to make the NAUT technique commercial. As the spot welded part had a high ultrasonic transmissivity, the result was shown as red. On the other hand, the part with an internal defect had a layer of air and low transmissivity, which was shown as blue. In addition, depending on the PRF (Pulse Repetition Frequency), an important factor that determines the measurement speed, the color sharpness showed differences. With the images obtained from CFRP specimens or an imaging device, it was possible to identify the shape, size and position of the internal defect within a short period of time. In this paper, it was confirmed in the above-described experiment that both internal defect detection and image processing of the defect could be possible using the NAUT technique. Moreover, it was possible to apply NAUT to the detection of internal defects in the spot welded parts or in CFRP parts, and commercialize its practical application to various fields.

• BMB Reports
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• v.44 no.3
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• pp.147-157
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• 2011

The meiotic process from the primordial stage to zygote in female germ cells is mainly adjusted by post-transcriptional regulation of pre-existing maternal mRNA and post-translational modification of proteins. Several key proteins such as the cell cycle regulator, Cdk1/cyclin B, are post-translationally modified for precise control of meiotic progression. The second messenger (cAMP), kinases (PKA, Akt, MAPK, Aurora A, CaMK II, etc), phosphatases (Cdc25, Cdc14), and other proteins (G-protein coupled receptor, phosphodiesterase) are directly or indirectly involved in this process. Many proteins, such as CPEB, maskin, eIF4E, eIF4G, 4E-BP, and 4E-T, post-transcriptionally regulate mRNA via binding to the cap structure at the 5' end of mRNA or its 3' untranslated region (UTR) to generate a closed-loop structure. The 3' UTR of the transcript is also implicated in post-transcriptional regulation through an association with proteins such as CPEB, CPSF, GLD-2, PARN, and Dazl to modulate poly(A) tail length. RNA interfering is a new regulatory mechanism of the amount of mRNA in the mouse oocyte. This review summarizes information about post-transcriptional and post-translational regulation during mouse oocyte meiotic maturation.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.53-63
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• 2009

This work proposes a 10b 100MS/s 27.2mW $0.8mm^2$ 0.18um CMOS ADC for WLAN such as an IEEE 802.11n standard. The proposed ADC employs a three-stage pipeline architecture and minimizes power consumption and chip area by sharing as many circuits as possible. Two multiplying DACs share a single amplifier without MOS switches connected in series while the shared amplifier does not show a conventional memory effect. All three flash ADCs use only one resistor ladder while the second and third flash ADCs share all pre-amps to further reduce power consumption and chip area. The interpolation circuit employed in the flash ADCs halves the required number of pre-amps and an input-output isolated dynamic latch reduces the increased kickback noise caused by the pre-amp sharing. The prototype ADC implemented in a 0.18um n-well 1P6M CMOS process shows the DNL and INL within 0.83LSB and 1.52LSB at 10b, respectively. The ADC measures an SNDR of 52.1dB and an SFDR of 67.6dB at a sampling rate of 100MS/s. The ADC with an active die area of $0.8mm^2$ consumes 27.2mW at 1.8V and 100MS/s.

• Nutrition Research and Practice
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• v.8 no.6
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• pp.655-661
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• 2014

BACKGROUND/OBJECTIVES: The purpose of this study was to examine the effects and associated mechanisms of arctiin, a lignan compound found in burdock, on adipogenesis in 3T3-L1 cells. Also, the effects of arctiin supplementation in obese mice fed a high-fat diet on adiposity were examined. MATERIALS/METHODS: 3T3-L1 cells were treated with arctiin (12.5 to $100{\mu}M$) during differentiation for 8 days. The accumulation of lipid droplets was determined by Oil Red O staining and intracellular triglyceride contents. The expressions of genes related to adipogenesis were measured by real-time RT-PCR and Western blot analyses. For in vivo study, C57BL/6J mice were first fed either a control diet (CON) or high-fat diet (HF) to induce obesity, and then fed CON, HF, or HF with 500 mg/kg BW arctiin (HF + AC) for four weeks. RESULTS: Arctiin treatment to 3T3-L1 pre-adipocytes markedly decreased adipogenesis in a dose-dependent manner. The arctiin treatment significantly decreased the protein levels of the key adipogenic regulators $PPAR{\gamma}$ and $C/EBP{\alpha}$, and also significantly inhibited the expression of SREBP-1c, fatty acid synthase, fatty acid-binding protein and lipoprotein lipase. Also, arctiin greatly increased the phosphorylation of AMP-activated protein kinase (AMPK) and its downstream target phosphorylated-acetyl CoA carboxylase. Furthermore, administration of arctiin significantly decreased the body weight in obese mice fed with the high-fat diet. The epididymal, perirenal or total visceral adipose tissue weights of mice were all significantly lower in the HF + AC than in the HF. Arctiin administration also decreased the sizes of lipid droplets in the epididymal adipose tissue. CONCLUSIONS: Arctiin inhibited adipogenesis in 3T3-L1 adipocytes through the inhibition of $PPAR{\gamma}$ and $C/EBP{\alpha}$ and the activation of AMPK signaling pathways. These findings suggest that arctiin has a potential benefit in preventing obesity.