• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1817-1823
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• 2009

A design of cascaded distributed amplifier with a broadband amplification is described in this paper. A medium power device with 23dBm, max output power under the optimal narrow-band power matching condition is adopted for the design and fabrication of the cascaded distributed amplifier. In general, conventional distributed amplifiers with the parallel connected input ports have a low gain, and previous cascaded distributed amplifiers show a relatively low output power of 10dBm at most, which is the upper limit of small signal amplification. However, the cascaded distributed amplifier in this paper shows the gain of $18.15{\pm}0.75dB$ and output power of 20dBm over $300MHz{\sim}2GHz$ from the measurement, so it can be well adopted as a wideband driver amplifier.

• Advances in nano research
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• v.14 no.4
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• pp.313-327
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• 2023

Zinc metal organic framework (MOF_Zn)-loaded goad nanoparticles (AuNPs) sol (Au@MOF_Zn), which was characterized by TEM, Mapping, FTIR, XRD, and molecular spectrum, was prepared conveniently by solvothermal method. The results indicated that Au@MOF_Zn had a very strong catalytic effect with the nanoreaction of AuNPs formation between sodium oxalate (SO) and HAuCl4. AuNPs in the new indicator reaction had a strong resonance Rayleigh scattering (RRS) signal at 370 nm. The indicator AuNPs generated by this reaction, which had the most intense surface enhanced Raman scattering (SERS) peak at 1621 cm -1. The new SERS/RRS indicator reaction in combination with specific aptamer (Apt) to fabricate a sensitive and selective Au@MOF_Zn catalytic amplification-aptamer SERS/RRS assay platform for carbendazim (CBZ), with SERS/RRS linear range of 0.025-0.5 ng/mL. The detection limit was 0.02 ng/mL. Similarly, this assay platform has been also utilized to detect oxytetracycline (OTC) and profenofos (PF).

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.3
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• pp.259-266
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• 2020

Cardiovascular diseases are the primary reason of mortality, among which myocardial infarction (MI) is the most dominant and prevalent. This study was considered to examine D-Limonene protective action against isoproterenol (ISO) induced MI. Wister male rats were dispersed into four groups. Normal and D-Limonene control group in which rats administered saline or D-Limonene. ISO control animals were administered saline for 21 days then challenged with ISO (85 mg/kg, subcutaneously) on 20th and 21st day for MI induction. D-Limonene pretreated group in which animals were pretreated with D-Limonene 50 mg/kg orally for 21 days then administered ISO on 20th and 21st day. MI prompted variations were assessed by myocardial infarction area determination, blood pressure (BP) alterations, cardiac injury biomarkers and inflammatory mediators measurements. For more depth investigation, both the apoptotic status was evaluated via measuring mRNA expression of Bcl-2 and Bax as well as mitogen-activated protein kinase-extracellular signal-regulated kinase (MAPK-ERK) signal transduction were investigated via Western blotting. MI group revealed significant infarcted area, blood pressure alterations, myocardial injury enzymes intensification together with inflammatory cytokines amplification. MI was associated with activation of MAPK-ERK signal pathway and apoptotic status within the myocardium. On the other hand, pretreated with D-Limonene demonstrated deterred infracted area, reduced myocardial enzymes, improved BP indices, lessened inflammatory levels. Furthermore, D-Limonene pretreatment caused a decline in MAPK proteins pathway and Bax relative mRNA expression, while intensifying Bcl-2 mRNA expression promoting that D-Limonene may constrain MI induced myocardial apoptosis. D-Limonene mitigated MI injury through MAPK/NF-κB pathway inhibition and anti-apoptotic effect.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.2
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• pp.146-153
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• 2008

Integrated humidity sensor system with two stages operational amplifier has been designed and fabricated by $0.8{\mu}m$ analog mixed CMOS technology. The system (28 pin and $2mm{\times}4mm$) consisted of Wheatstone-bridge type humidity sensor, resistive type humidity sensor, temperature sensors and operational amplifier for signal amplification and process in one chip. The poly-nitride etch stop process has been tried to form the sensing area as well as trench in a standard CMOS process. This modified technique did not affect the CMOS devices in their essential characteristics and gave an allowance to fabricate the system on same chip by standard process. The operational amplifier showed the stable operation so that unity gain bandwidth was more than 5.46 MHz and slew rate was more than 10 V/uS, respectively. The drain current of n-channel humidity sensitive field effect transistor (HUSFET) increased from 0.54 mA to 0.68 mA as the relative humidity increased from 10 to 70 %RH.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4473-4482
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• 2010

The examination of pulse, which is a typical palpation technique in the oriental medicine, has been used conventional analog system for discrimination of 28 pulses. However, the clipping phenomenon in the pulses, which used same feature extraction technique with ECG signals, has been occurred in analog system due to feature extraction method and over amplification from the input signals. It caused inaccurate to analyze the pulse signals. In this paper, we propose a digital filter design technique based on Prony's method for signal modeling and C-spline interpolation for feature extraction from pulse signal to compensate analog pulse detection system. In addition, we suggest a compensated electronic pulse detection system comprising new pulse analyzing algorithm and shape analysis technique for pulses, which were difficult to use in analog system. The feasibility for new proposed system has been confirmed comparing output signals between electronic pulse detection system having proposed filter design techniques with pulse analyzing algorithm and conventional analog system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.12
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• pp.136-144
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• 2021

The purpose of this study was to develop and verify a precision transmission error measurement system for a gear pair. The transmission error measurement system of the gear pair was developed as a measurement unit, signal processing unit, and signal analysis unit. The angular displacement for calculating the transmission error of the gear pair was measured using an encoder. The signal amplification, interpolation, and transmission error calculation of the measured angular displacement were conducted using a field-programmable gate array (FPGA) and a real-time processor. A high-pass filter (HPF) was applied to the calculated transmission error from the real-time processor. The transmission error measurement test was conducted using a gearbox, including the master gear pair. The same test was repeated three times in the clockwise and counterclockwise directions, respectively, according to the load conditions (0 - 200 N·m). The results of the gear transmission error tests showed similar tendencies, thereby confirming the stability of the system. The measured transmission error was verified by comparing it with the transmission error analyzed using commercial software. The verification showed a slight difference in the transmission error between the methods. In a future study, the measurement and analysis method of the developed precision transmission error measurement system in this study may possibly be used for gear design.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4570-4575
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• 2023

Noise and Radio-frequency interference or RFI causes a significant restriction on the Free induction Decay or FID signal detection of the Nuclear Quadrupole Resonance procedure. Therefore, using this method in non-isolated environments such as industry and ports requires extraordinary measures. For this purpose, noise reduction algorithms and increasing signal-to-noise-and-interference ratio or SNIR have been used. In this research, sodium nitrite has been used as a sample and algorithms have been tested in a non-isolated environment. The resonant frequencies for the 150 g of test sample were measured at 303 K at about 1 MHz and 3.4 MHz. The main novelty in this study was, (1) using two types of antennas in the receiver to improve adaptive noise and interference cancellation, (2) using a separate helical antenna in the transmitter to eliminate the duplexer, (3) estimating the noise before sending the pulse to calculate the weighting factors and reduce the noise by adaptive noise cancellation, (3) reject the interference by blanking algorithm, (4) pulse integration in the frequency domain to increase the SNR, and (5) increasing the detection speed by new pulse integration technique. By interference rejection and noise cancellation, the SNIR is improved to 9.24 dB at 1 MHz and to 7.28 dB at 3.4 MHz, and by pulse integration 44.8 dB FID signal amplification is achieved, and the FID signals are detected at 1.057 MHz and 3.402 MHz at room temperature.

• Parasites, Hosts and Diseases
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• v.51 no.3
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• pp.269-277
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• 2013

Amoebic keratitis (AK) caused by Acanthamoeba is one of the most serious corneal infections. AK is frequently misdiagnosed initially as viral, bacterial, or fungal keratitis, thus ensuring treatment delays. Accordingly, the early detection of Acanthamoeba would contribute significantly to disease management and selection of an appropriate anti-amoebic therapy. Recently, the loop-mediated isothermal amplification (LAMP) method has been applied to the clinical diagnosis of a range of infectious diseases. Here, we describe a rapid and efficient LAMP-based method targeting Acanthamoeba 18S rDNA gene for the detection of Acanthamoeba using clinical ocular specimens in the diagnosis of AK. Acanthamoeba LAMP assays detected 11 different strains including all AK-associated species. The copy number detection limit for a positive signal was 10 DNA copies of 18S rDNA per reaction. No cross-reactivity with the DNA of fungi or other protozoa was observed. The sensitivity of LAMP assay was higher than those of Nelson primer PCR and JDP primer PCR. In the present study, LAMP assay based on directly heat-treated samples was found to be as efficient at detecting Acanthamoeba as DNA extracted using a commercial kit, whereas PCR was only effective when commercial kit-extracted DNA was used. This study showed that the devised Acanthamoeba LAMP assay could be used to diagnose AK in a simple, sensitive, and specific manner.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.8
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• pp.857-864
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• 2010

In this paper, we analyse the effect of the path imbalances(gain and phase mismatches) in LINC(LInear amplification with Nonlinear Component) system, and propose a simple scheme using LUTs(Look Up Table) to compensate the path imbalances. The EVM(Error Vector Magnitude) and ACPR(Adjacent Channel Power Ratio) of the LINC system are degraded significantly by the path imbalances because it adopts an outphasing technique. The EVM and ACPR are theoretically extracted for two variables(gain and phase mismatch factors) and 2-D LUTs for those are generated based on the analysis. The efficient and simple compensation scheme for the path imbalances is proposed using the 2-D LUTs. A LINC system with the suggested compensation scheme is implemented, and the proposed method is verified with an experiment. A 16-QAM signal with 1.5 MHz bandwidth is used. Before the compensation, the path gain ratio was 95 % and phase error was $19.33^{\circ}$. The proposed scheme adjusts those values with 99 % and $0.5^{\circ}$, and improves ACPR about 18.1 dB.

• Journal of IKEEE
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• v.26 no.3
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• pp.510-514
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• 2022

In this paper, we propose the development of high-sensitivity low-end radiation measuring sensor module. The proposed measurement sensor module is a scintillator + photomultiplier(SiPM) sensor optimization structure design, amplification and filter and control circuit design for sensor driver, control circuit design including short-distance communication, sensor mechanism design and manufacturing, and GUI development applied to prototypes consists of, etc. The scintillator + photomultiplier(SiPM) sensor optimization structure design is designed by checking the characteristics of the scintillator and the photomultiplier (SiPM) for the sensor structure design. Amplification, filter and control circuit design for sensor driver is designed to process fine scintillation signal generated by radiation with a scintillator using SiPM. Control circuit design including short-distance communication is designed to enable data transmission through MCU design to support short-range wireless communication function and wired communication support. The sensor mechanism design and manufacture is designed so that the glare generated by wrapping a reflective paper (mirroring) on the outside of the plastic scintillator is reflected to increase the efficiency in order to transmit the fine scintillation signal generated from the plastic scintillator to the photomultiplier(SiPM). The GUI development applied to the prototype expresses the date and time at the top according to each screen and allows the measurement unit and time, seconds, alarm level, communication status, battery capacity, etc. to be expressed. In order to evaluate the performance of the proposed system, the results of experiments conducted by an authorized testing institute showed that the radiation dose measurement range was 30 𝜇Sv/h ~ 10 mSv/h, so the results are the same as the highest level among products sold commercially at domestic and foreign. In addition, it was confirmed that the measurement uncertainty of ±7.4% was measured, and normal operation was performed under the international standard ±15%.