• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.21-30
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• 2007

A multiwavelength spectrophotometric titration method was applied to study protolytic constants of four water-soluble vitamins, folic acid(vitamin B9 or B0), thiamine(vitamin B1), riboflavin(vitamin B2) and pyridoxal (vitamin B6) in binary ethanol-water mixtures at 25oC and an ionic strength of 0.1M NaNO3. The protolytic equilibrium constants, spectral profiles, concentration diagrams and also the number of components has been calculated from the curve fitting of the pH-absorbance data with appropriate mass balance equations by an established factor analysis model. DATAN program was used for determination of acidity constant and SPECFIT program was used for calculation of standard deviations and partial correlation coefficients. A glass electrode calibration procedure based on the four parameter equation pH=α+SpcH+JH+[H+]+ JOH-Kw/[H+] based on the Gran,s plots was used to obtain pH-readings in the concentration scale (pcH). The effect of the solvent on the protolytic constants was discussed.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.831-834
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• 2002

When any part of the pacemaker system is infected, all pacemaker hardware should be removed, because reinfection rates of 51% to 77% have been noted in patients whose infected pacemaker system has been only partially explanted. The removal of infected leads during cardiopulmonary bypass prevents mechanical injury as well as the spread of infection and vegetation. We report one case of endocarditis by staphylococcus aureus with infected transvenous pacing lead which was migrated into the heart from the left subclavian vein. We removed the migrated pacing lead and vegetation under cardiopulmonary bypass.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.512-515
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• 2001

The heifer electrocardiograph is a widely progressing research which is used in judgement to existence for a heart disease and analyzes electric potential changes of heart movement during continuous living of everyday after attaching to body portable holler recorder for twenty-four hours. In order to obtain electrocardiogram clearly, it must eliminate that 60Hz power line interference, baseline wandering, noise of muscle constriction. In holter electrocardiogram, the most big problem which is recorded signal of ECG(electrocardiogram) is a baseline wandering elimination, which is occurred by rhythm of respiration and muscle constriction of part from attaching to an electrode. Such baseline is roughly irregular wandering and shaking up and down therefore the part of baseline wandering elimination is very important because it is difficult of ECG diagnosis. In this study, it is stabilized baseline wandering in analog part as implementation f real-time signal processing digital filter so it is applicable to analyze patient's heart disease by way of design of baseline wandering elimination system.

• Korean Journal of Materials Research
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• v.5 no.8
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• pp.929-935
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• 1995

In order to develop COG (Chip On Glass) technology for LCD module interconnecting the driver IC to Al pad electrode on the glass substrate, Anisotropic Conductive Adhesive(ACA) process, the most promising one among COG technologies, was investigated. ACA process was carried out by two steps, dispensing of ACA resin in the bonding area and curing by W radiation. Load on the chip was ranged from 2.0 to 15kg and the chip was heated at about 12$0^{\circ}C$. In resin, the density of conductive particles coated with Au or Ni at the surface were 500, 1000, 2000 and 4000 particles/$\textrm{mm}^2$, and the diameter of particles were 5, 7 and 12${\mu}{\textrm}{m}$. As a result of the experiments, ACA process using ACA particle of diameter and density of 5${\mu}{\textrm}{m}$ and 4000 particles/$\textrm{mm}^2$ respectively shows optimum characteristic with the stabilzed bonding properties and contact resistance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.28-33
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• 2015

The needle electrode is inserted into the cross-linked polyethylene(XLPE) which is the ultra high voltage cable for electric power. By changing the tilt of the needle electrode, we investigated how the void and the thickness of the insulating layer influence the partial discharge(PD) characteristics and the insulating breakdown. In order to investigate the PD characteristics, The XLPE cable was used to the specimens and the tungsten electrode was used with the needle electrode. And the inner semi-conductive layer material of XLPE cable was used with the negative electrode by bonding with the use of conduction tape. The size of the specimens was manufactured to be $16{\times}40{\times}30[mm^3]$. We confirmed the effect on changing the PD characteristics according to the changing voltage and the tilt of the electrode after applying the voltage on the electrode from 1[kV] to 40[kV] at room temperature. In the PD characteristics, it was confirmed that the PD current of air void specimens with tilt was unstable more than that of no void specimens with tilt. It was also confirmed that the breakdown voltage was decreased because the effect of air void is more active than the change of the needle electrode tilt in the specimen with air void inside the insulation.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.253-257
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• 2017

Graphene is a monolayer carbon material which consists of $sp^2$ bonding between carbon atoms. Its excellent intrinsic properties allow graphene to be used in various research fields. Many researchers believe that graphene is suitable for electronic device materials due to its high electrical conductivity and carrier mobility. Through chemical doping, n- or p-type graphene can be obtained, and consequently graphene-based devices which have more comparable structure to common semiconductor-based devices can be fabricated. In our research, we introduced the dielectrophoresis process to the chemical doping step in order to improve the effect of chemical doping of graphene selectively. Under 10 kHz and $5V_{pp}$ (peak-to-peak voltage), doping was conducted and the Au nanoparticles were effectively formed, as well as aligned along the edges of graphene. Effects of the selective chemical doping on graphene were investigated through Raman spectroscopy and the change of its electrical properties were explored. We proposed the method to enhance the doping effect in local region of a graphene layer.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.5
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• pp.391-395
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• 2015

A 15-Lead ECG has been developed to diagnose posterior wall diseases of the heart that a 12-Lead ECG cannot diagnose. However, 15-Lead ECG data for developing heart-diseases-detecting algorithm are limited, and previous ECG simulators cannot predict the ECG waveform according to the changes in electrode. To solve these problems, the lumped parameter model (LPM), which divides the heart into 15 sections with varying electrical capacitance and electrical resistance. To imitate the electrical conduction in the heart, each node was connected to a current source and delivered the specific current considering the positions and time delay. The purpose of this study is to acquire the waveform that can be used in an ECG by delivering the specific current to LPM.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.1
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• pp.13-21
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• 2001

The discharge characteristics of 3 electrcdes AC surface discharge plasma display were analyzed. For an unstable state of the discharge which appeared at the maximum discharge voltage, it is found that a parbal erase of the wall charge by the second discharge is a cause. Based on the second discharge, new operation margin considering the interrelation between the address discharge and the display discharge was defined and the validity of it was verified by the experiments. It is necessary to decrease the acklress pulse width for high-speed addressing. However, the operation margin of the ackIress pulse decreases as the pulse width of it becomes narrower. If the address pulse width is wider than l[ps], the operation margin of the display discharge is not related to the address pulse width. From the experimental result, image or 8bit 253 gray level was displayed on PDP with the cell structure of the HDTV class by using the high-speed address ADS drive methcd with pulse width of $1[{\mu}s]$ and the brightness of $560[cd/m^2]$ was obtained. ained.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.903-906
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• 2011

The electroplating and electro-less plating methods have been applied for the high density chip interconnect of the Copper Pillar Tin Bump (CPTB) preparation. The CPTB was prepared, which had been electroplated about $100{\mu}m$ pitch of copper layer firstly, and then the Tin layer was deposited on the copper pillar surface to protect the oxidation of it. It was also very important to get uniform thickness of electroplated copper layer, though it was difficult and sensitive. In order to control the thickness distribution, it was examined that the current separating disk of Insulating Gate with a hole in the center was installed between electrodes. The current flows through the center hole of the Insulating Gate in the cylindrical electroplating bath and the other parts were blocked to protect current flowing. The main current flowed through the center hole of the Insulating Gate directly to the opposite electrode of wafer disk. As the results, it was verified that the copper layer was thick in the center part of wafer disk with distribution of thinner to the outer part toward edge.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.324-326
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• 2011

Measuring a biosignal during sleep is an important part of diagnosis and treatment of sleep disorder and also used to determine the general quality of sleep. As in current polysomnography, Contact method, which requires the attachment of electrodes to the skin, is the typical method to measure a biosignal during sleep. The procedure of this test is often considered to be inconvenient and tiresome because it requires attaching the device to the skin for each observation, and also limits free movement throughout the test. For this reason, the research on the acquiring the biosignal information without any attachment of a fixture on the skin is being conducted actively these days. In this study, it is suggested to check the heart rate per minute and the presence of breathing by placing a Piezo, which is a film type of pressure sensor, on the bed.