• Journal of Sensor Science and Technology
• /
• v.26 no.5
• /
• pp.342-347
• /
• 2017

We present a precision instrument amplifier (IA) designed for bio-potential acquisition. The proposed IA employs a capacitively coupled instrument amplifier (CCIA) structure to achieve a rail-to-rail input common-mode range and low gain error. A positive feedback loop is applied to boost the input impedance. Also, DC servo loop (DSL) with pseudo resistors is adopted to suppress electrode offset for bio-potential sensing. The proposed amplifier was designed in a $0.18{\mu}m$ CMOS technology with 1.8V supply voltage. Simulation results show the integrated noise of $1.276{\mu}Vrms$ in a frequency range from 0.01 Hz to 1 KHz, 65dB SNR, 118dB CMRR, and $58M{\Omega}$ input impedance respectively. The total current of IA is $38{\mu}A$. It occupies $740{\mu}m$ by $1300{\mu}m$ including the passive on-chip low pass filter.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.515-518
• /
• 2005

In this paper, we report on our theoretical study on the effect of surface anchoring. Molecular dynamics as well as optical characteristics of PVA cell are computer-simulated with 3D-FEM numerical solver, TechWiz $LCD^{(R)}$. Although simulation parameters are the same except for the consideration of surface anchoring, the simulation reveals that optical transmittance is improved by more than 8% for the weak anchoring case with comparison to the strong anchoring case. Moreover, capacitance between pixel and common electrode is 7% lower for the strong anchoring than that for the weak anchoring. This implies that there exists an appreciable difference between the strong anchoring case and the weak anchoring case. It is very important to take the effect of surface anchoring into account in order to figure out the optical characteristics of an LCD cell more accurately.

• Journal of the Korean Chemical Society
• /
• v.27 no.2
• /
• pp.111-116
• /
• 1983

Three component $Ag_2S-PbS-PbWO_4$ electrodes have been prepared and evaluated for sensitivity to tungstate. The 51.71 : 16.64 : 31.65(w/w%) composition is superior in terms of potentiometric response, stability, rapidity of response and reproducibility. Testing was done over the concentration range $10^{-1}~10^{-4}M WO_4^{2-}$ in $0.1F-NH_4Ac-NH_4OH$ buffer at pH 8.00 with constant ionic strength. The quality of response is similar to that of corresponding phosphate-sensing electrode. Many common ions interfere.

• Journal of Korean Neurosurgical Society
• /
• v.46 no.3
• /
• pp.273-276
• /
• 2009

A 54-year-old man experienced injury to the second finger of his left hand due to damage from a paintball gun shot 8 years prior, and the metacarpo-phalangeal joint was amputated. He gradually developed mechanical allodynia and burning pain, and there were trophic changes of the thenar muscle and he reported coldness on his left hand and forearm. A neuroma was found on the left second common digital nerve and was removed, but his symptoms continued despite various conservative treatments including a morphine infusion pump on his left arm. We therefore attempted median nerve stimulation to treat the chronic pain. The procedure was performed in two stages. The first procedure involved exposure of the median nerve on the mid-humerus level and placing of the electrode. The trial stimulation lasted for 7 days and the patient's symptoms improved. The second procedure involved implantation of a pulse generator on the left subclavian area. The mechanical allodynia and pain relief score, based on the visual analogue scale, decreased from 9 before surgery to 4 after surgery. The patient's activity improved markedly, but trophic changes and vasomotor symptom recovered only moderately. In conclusion, median nerve stimulation can improve chronic pain from complex regional pain syndrome type II.

• Journal of Environmental Science International
• /
• v.23 no.10
• /
• pp.1745-1753
• /
• 2014

Sediment microbial fuel cell (SMFC), equipped with Zn, Al, Cu, Fe or graphite felt (GF) anode and marine sediment, was performed. Graphite felt was used as a common cathode. SMFC was single chambered and did not use any redox mediator. The aim of this work was to find efficient anodic material. Oxidation reduction potential (ORP), cell voltage, current density, power density, pH and chemical oxygen demand (COD) were measured for SMFC's performance.. The order of maximum power density was $913mWm^{-2}$ for Zn, $646mWm^{-2}$ for Fe, $387.8mWm^{-2}$ for Cu, $266mWm^{-2}$ for Al, and $127mWm^{-2}$ for graphite felt (GF). The current density over voltage was found to be strongly correlated with metal electrodes, but the graphite felt electrode, in which relatively weaker electricity was observed because of its bio-oriented mechanism. Metal corrosion reactions and/or a complicated microbial electron transfer mechanism acting around the anodic compartment may facilitate to generate electricity. We presume that more sophisticated selection of anodic material can lead to better performance in SMFC.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.6
• /
• pp.622-632
• /
• 2004

We have studied how liquid crystal's rubbing direction and voltage driving method affect generation of disclination line. At first, generation of disclination line in vertical alignment(VA) cell and VA-twisted nematic(TN) cell has been examined. When liquid crystal's rubbing direction of bottom substrate was 0$^{\circ}$, the degree of generated disclination line was the smallest value. Further, the generation of disclination line above the electrode is less in the frame inversion than in the line inversion. Secondly, we have examined a generation of disclination line in reflective fringe-field switching cell. When the distance between common electrodes is over 3 ${\mu}{\textrm}{m}$ with on-state of one pixel and off-state of neighboring pixels, the reflectance appears only on-state pixel without generating reflectance in adjacent pixels.

• Journal of IKEEE
• /
• v.23 no.2
• /
• pp.524-528
• /
• 2019

Although different types of discharge cells exist, in common it is the primary goal for all discharge cells to have lower drive voltages and higher efficiency characteristics. To improve these factors, many studies are conducted that prolong the discharge path inside the discharge cell or change the composition of the working gas. In this paper, the two-dimensional fluid simulation was used to calculate the discharge voltage (firing voltage and sustain voltage) and the change in luminance and luminous efficacy according to the change in gap distance between discharge electrodes. In addition, we looked at changes in various charged particles, exciting particles and VUV particles, and studied the causes of the resulting values.

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

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.11 s.114
• /
• pp.1120-1131
• /
• 2006

This paper describes the numerical analysis techniques using the Combined Integration/Matrix Method to calculate ground potential rise which can be occurred in the various grounding systems. Combined Integration/Matrix Method is used to reduce the error and computation time with the analytical integration equation and the proper segmentaion of earth embedded conductor. To do it, optimal segmentaion method for the buried conductors is presented through error analysis which is capable of applying the practical scaled various grounding systems. The optimum length of segmented element is much co-related with the buried depth of grounding electrode and the maximum length of buried electrode. As a result, less 3 precent errors was obtained by proposed model. The proposed model is applied to verify an effect of multi-grounding problems which was aroused much controversy with separated or common grounding between the high power grounding system and low power grounding system such as signal and telecommunication grounding.

• Annals of Clinical Neurophysiology
• /
• v.6 no.2
• /
• pp.98-102
• /
• 2004

Background: Carpal tunnel syndrome (CTS) is a common condition characterized by entrapment neuropathy of the median nerves. Clinical manifestations are the most important findings for diagnosis and assessment of therapeutic effects. But, objective indicators, such as electrophysiological findings, are also valuable supplementary tools. This study investigated the relationship between clinical grading and sensory nerve conduction velocity (SNCV) of median proper palmar digital nerve (MPPDN) in CTS patients. Method: This study was done on 90 upper limbs of 53 patients with CTS (men: 6, women: 47, age: 26~69 years, mean age; 52 years). Each SNCV of MPPDN was recorded with bar electrode using antidromic method. Each SNCV was compared with clinical grading of CTS. The clinical grades of CTS were designated as follows; group 1 is mild symptoms, 2 is moderate symptoms, and 3 is severe and longstanding symptoms. Result: In thumb, the SNCV of MPPDN was not different significantly between 3 groups (p=0.817). In the index finger, the SNCV was the fastest in the group 1, but faster in group 3 than in group 2 (p=0.001). In the middle and ring fingers, SNCV was decreased in higher clinical grading groups (middle finger: p=0.015, ring finger: p=0.044). Conclusion: SNCV of MPPDN of middle and ring finger correlated with the clinical grading of CTS. SNCV of index finger was the fastest in group 1. But SNCV of thumb did not correlate with the clinical grading of CTS.