• Journal of the Institute of Convergence Signal Processing
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• v.9 no.4
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• pp.280-287
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• 2008

For the reduction of common-mode noise level in Indirect-contact ECG (IDC-ECG) measurement a driven-right-leg grounding method was a lied to the IDC-ECG. Because the IDC-ECG does not require any direct contact between the electrodes and the human skin. it is adequate for un-constraining long-term ECG measurement at home and its various applications are now under development. However, larger 60 Hz noise induced by power line a ears in IDC-BCG than in conventional ECG, that is a restriction of IDC-ECG a application. In this study, the driven-right-leg ground which has been used in conventional direct-contact ECG, was adapted to the IDC-ECG measurement by feedback of the inversion of amplified common-mode noise to the body through the conductive fertile laid on the chair seat By this study, indirect-contact driven-right-leg ground was developed and it was shown to work stably. It was shown that the level of 60Hz power line noise was reduced to about -40 dB when the driven-right-leg gain was 1000. This study shows that we can extend the upper limit of the frequency band of IDC-ECG to 100Hz from 30Hz which is conventional upper limit in IDC-ECG, and we can raise the ground impedance between the body and conductive textile. So it is expected that the application area of the IDC-ECG will be extended by the results of this study.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.107-113
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• 2014

A VCO (Voltage Controlled Oscillator) and a divide-by-4 high speed frequency divider are implemented using 65nm CMOS technology for 60GHz wireless communication system. The mm-wave VCO was designed by NMOS cross-coupled LC type using current source. The architecture of the divide-by-4 high speed frequency divider is differential ILFD (Injection Locking Frequency Divider) with varactor to control frequency range. The frequency divider also uses current sources to get good phase noise characteristics. The measured results show that the VCO has 64.36~67.68GHz tuning range and the frequency divider divides the VCO output by 4 exactly. The high output power of 5.47~5.97dBm from the frequency divider is measured. The phase noise of the VCO including the frequency divider are -77.17dBc/Hz at 1MHz and -110.83dBc/Hz at 10MHz offset frequency. The power consumption including VCO is 38.4mW with 1.2V supply voltage.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.1
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• pp.47-55
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• 2005

These studies were done to know decalcification methods to reduce the time of decalcification for quick bone tissue diagnosis. When bone tissue was decalcified with 10 % formic acid at room temperature, decalcification and hematoxylin & eosin (H&E) stains were complete and satisfactory after 12 hours, but some of the tissue sections fell off during staining. In this way, decalcification, H&E stains were complete and satisfactory after 24 hours, 36 hours and 48 hours, tissue sections didn't fall off during staining. When bone tissue was decalcified with 10 % formic acid in a $60^{\circ}C$ paraffin oven, decalcification and H&E stains were complete and satisfactory after 6 hours, but some tissue sections fell off during staining. In this way, decalcification and tissue sections were complete, with no falling off during staining after 8 hours, 10 hours, 12 hours, 14 hours, 24 hours, or H&E stains were satisfactory from 8 hours to 12 hours, but H&E stains appeared to reddish nucleus after 14 hours and 24 hours. Bone tissue was decalcified with 10 % formic acid for 6 hours, 12 hours and 24 hours at DECAL machine frequencies of 15 Hz and 45 Hz, and for 6 hours, 12 hours and 24 hours at a DECAL machine frequency of 90 Hz. Decalcification and H&E stains were complete and satisfactory after 6 hours at the 15 Hz and 45 Hz DECAL settings. Some of the tissue sections fell off during staining at the 15 Hz DECAL machine setting. At the 90 Hz setting, decalcification, H&E stains, and tissue sections were complete and satisfactory with no falling off during staining after 4 hours. In this way, decalcification, H&E stains, and tissue section were complete and satisfactory with no falling off during staining after 12 hours, 24 hours at all machine settings. Bone tissue was decalcified with 10 % formic acid for 6 hours, 12 hours and 24 hours at $37^{\circ}C$ 3 hours, 6 hours and 12 hours at $45^{\circ}C$ and 1 hours, 5 hours and 10 hours at $60^{\circ}C$ with the RHS-1 machine setting at 60Hz. At the temperatures of $37^{\circ}C$, $45^{\circ}C$, and $60^{\circ}C$ decalcification, H&E stains, and tissue sections were complete and satisfactory, with no falling off during staining except for after 6 hours at $37^{\circ}C$. 3 hours, 1 hours, or decalcification, H&E stains, and tissue sections were complete and satisfactory with no falling off during staining after 12 hours and 24 hours at $37^{\circ}C$, 6 hours and 12 hours at $45^{\circ}C$, and 5 hours at $60^{\circ}C$. But H&E stains appeared to reddish nucleus after 10 hours at $60^{\circ}C$. From the above reults, the authors were able to deduce that decalcification is accelerated by heat and frequency. We therefore think that it is necessary for machines which are similar to the RHS-1 machine to be maintained at the temperature evenly with agitation effect for quick decalcification.

• The Magazine of the IEIE
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• v.28 no.2
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• pp.31-41
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• 2001

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.1
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• pp.19-24
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• 1999

This paper is second part on the auditory thresholds and fish behaviors to the underwater sounds for luring of target species at the set-net in the coast of Cheju. In order to obtain the critical ratio of yellow tails(Seriola quinqueradiata) and the emission level of underwater sound for luring of them, we make experiments to measure the auditory threshold of them using conditioning with electric shock. In state that the white noise with 10dB higher sound pressure level than ambient noise is emitted, the auditory thresholds of yellow tails are measured with 100~116.5dB and they are higher than those in state of no emission of white noise by the masking effects of it. Although sound pressure level of background noise go down, the auditory thresholds go up with frequency above than 300Hz.The critical ratio of yellow-tails in frequency of 80Hz, 100Hz, 200Hz, 500Hz, 800Hz are 46dB, 40dB, 50dB, 52dB, 60dB, 70dB respectively. The sound pressure level of which the signal sound is recognized by yellow tails under the ambient noise is above 100dB and the critical ratio of them is above 40dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.947-954
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• 1999

A new low phase noise Dielectric Resonator Parallel Feedback Oscillator(DRPFO) that is proposed in this paper has a simple structure so that it can be fabricated in low cost and with high performance. The proposed DRPFO is in a feedback loop oscillator configuration, which is composed of a low noise amplifier, a power amplifier, a power attenuator, a power divider and a parallel resonator feedback element that consists of a dielectric resonator coupled with two microstrip lines. The measured phase noise of DRPFO was less than -81 dBc/Hz at offset frequency 1 kHz of 10.75 GHz carrier frequency, and the frequency stability of DRPFO was less than $\pm$200 kHz over the temperature range of -40$^{\circ}$C to +60$^{\circ}$C.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.127-130
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• 2002

Step-edge dc SQUID magnetometers have been fabricated on sapphire substrate. Ce$O_{2}$ buffer layer and $YBa_{2}$$Cu_{3}$ $O_{7}$(YBCO) films were deposited in-situ on the low angle (~$35^{\circ}$)steps formed on the substrates. Typical 5-$\mu$m-wide junction has $R_{N}$ of 4 $\Omega$ and $I_{c}$ of 60 $\mu$A with $I_{c}$$R_{N}$ product of 240 $\mu$V at 77 K. According to applied bias current, depth of voltage modulation was changed and maximum voltage was measured 100~300 fT/$\checkmark$ Hz at 100 Hz, and about 1.5 pT/$\checkmark$ Hz at 1 Hz. For ac bias reversal method, field noise was decreased in the 1/f region. The QRS peak of magneto-cardiogram was measured 50 pT in the magnetically shielded room.

• Phonetics and Speech Sciences
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• v.2 no.3
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• pp.151-156
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• 2010

The purpose of this study was to develop a computer-animated pure tone audiometry for screening (CAPTAS) for toddler and to determine its validity and reliability. The CAPTAS utilizes an animated cartoon story producing visual and auditory stimuli. The intensities were 40 dB, 60 dB, 80 dB. The frequencies were 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz. The subjects were 20 (9 males and 11 females) severely hearing impaired children. As a result, The correlation coefficient between mean hearing threshold of children who were able to perform PTA and average hearing threshold of CAPTAS was performed and it revealed CAPTAS's high validity. And to verify the reliability of the re-test, all children had the CAPTAS and repeated it periodically. The result confirmed the reliability.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1856-1861
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• 2010

To reduce a high fault current, neutral ground reactors (NGR) were installed in the Korean substation. Current with several harmonic components flows in a NGR due to load unbalance in normal steady state and magnetic fields with several harmonic components are also generated around a NGR. As results of study, we found magnetic fields around a NGR in Korean substation included two harmonics, 180Hz and 540Hz. Magnetic fields of 180 Hz increased 3 times more current density inside a worker near a NGR than same magnitude magnetic fields of 60 Hz. We know a worker near a NGR may not meet ICNIRP guideline of 10(mA/$m^2$) due to several harmonic components.

• Journal of Korean Dental Science
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• v.7 no.2
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• pp.99-105
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• 2014

Herpes zoster (HZ) is an acute, unilateral inflammatory viral infection characterized by a rash with painful blisters in a localized area of the body. HZ is often associated with intense pain in the acute phase and presents postherpetic neuralgia in the chronic phase. During the prodromal stage of the HZ from the trigeminal nerve, however, the only presenting symptom may be odontalgia, which could be particularly difficult to diagnose. This distinctive syndrome occurs predominantly in the immunocompromised or elderly individuals. In this article, we report a case of HZ developed in the trigeminal nerve of a 60-year-old immunocompromised female patient, whose symptoms including atypical, non-odontogenic odontalgia had improved after series of antiviral treatments.