• Journal of Welding and Joining
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• v.28 no.5
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• pp.99-105
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• 2010

Inverter DC resistance spot welding process has been very widely used for joining such as automotive body sheet metal. Because the lobe area of DC welding is larger than AC welding and DC welding has low electrode wear. So the use of Inverter DC resistance spot welding process has been further increased. And the application of high tensile steel is growing for light weight vehicle. To improve the weldability of high strength steel, the development of Inverter DC resistance spot welding system is more conducted. However, Inverter DC resistance spot welding system has a few problems. Current waveform is unstable and the expulsion has been occurred by characteristics of steel. In this study, inverter DC resistance spot welding system was made. And Fuzzy control algorithm was applied for constant current. The genetic algorithm was applied to optimize the fuzzy scaling factors, in order to optimize the fuzzy control.

• Progress in Medical Physics
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• v.25 no.1
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• pp.1-7
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• 2014

Hyperthermia is effective treatment modality when it combine with the radiotherapy treatment. It is important to verify the temperature distribution of (patient's) body for the safety and effective treatment during raising the temperature. In this study, we raised the temperature in agar phantom using radio frequency (RF) Hyperthermia and protocol that manufacture recommend. Temperature distribution measured 5 section of 5 cm thickness with agar phantom. When the temperature was raised according to the increase energy. Temperature distribution was elevated at similar domain regardless of energy. The temperature tend to be increased at up side then bottom side and also increase when A large electrode was used than small one.

• Journal of the Korea Convergence Society
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• v.9 no.3
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• pp.257-263
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• 2018

Hyperthermia supplies RF high-frequency energy above 1MHz to the tumor tissue through the electrodes. And the temperature of the tumor tissue is increased to $42^{\circ}C$ or more to cause thermal necrosis. A mathematical model can be derived a human body model for absorption and transmission of electromagnetic energy in the human model and It is possible to evaluate the distribution of temperature fields in biological tissues. In this paper, we build the human model based on the adult standard model of the geometric shape of the 3D model and use the FVM code. It is assumed that Joule heat is supplied to the anatomical model to simulate the magnetic field induced by the external electrode and the temperature distribution was analyzed for 0-1,200 seconds. As a result of the simulation, it was confirmed that the transferred energy progressively penetrates from the edge of the electrode to the pulmonary tumors and from the skin surface to the subcutaneous layer.

• Journal of the Korean Ceramic Society
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• v.39 no.4
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• pp.359-366
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• 2002

The purpose of this study is to investigate the properties of LSGM electrolyte and LSM cathode. The unit cell based on the optimum conditions and processing for high performance was fabricated and measured. The single phase of $LaGaO_3$ was obtained on sintering at $1500^{\circ}$ for 6h with composition of $(La_{0.85}Sr_{0.15})(Ga_{0.8}Mg_{0.2})O_{3-\delta}와 (La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$ and $(La_{0.85}Sr_{0.15})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$. The grain size of the sintered body was about $10∼30{\mu}m$ and electrical conductivity was 0.13 S/cm measured at $800^{\circ}$. The single phase of $LaMnO_3$ structure in $(La1-xSrx)MnO_3$ system was obtained at x=0∼0.2 and the particle size of the synthesized powder was about 40 nm. The unit cell was prepared by firing at $1200^{\circ}$ for 1h with $(La_{0.9}Sr_{0.1})MnO_3$ cathode and 0.9NiO-0.1YSZ anode screen-printed on surfaces of $(La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$ electrolyte. The grain size of the electrode was close to $1{\mu}m$ and the electrode had porous structure. The maximum power density of unit cell showed $0.3W/cm^2$ at $800^{\circ}$.

• Analytical Science and Technology
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• v.13 no.4
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• pp.466-473
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• 2000

The complex formation constants (${\beta}_{MLn}$) of potassium and various sodium-selective neutral carriers in solvent polymeric membranes have been determined using solvent polymeric membrane-based optodes and ion-selective electrodes (ISEs). Two different types of PVC-based membranes containing the H^+selective chromoionophore (ETH 5294) with and without a sodium ionophore (4-tert-bntylcalix[4]arenetetraacetic acid tetraethyl ester, ETH 2120, bis[(12-crown-4)methyl] dodecylmethylmalonate or monensin methyl ester) were prepared and their optical responses to either the changes in alkali metal cation (e.g., sodium and potassium) concentrations at a fixed pH (0.05 M Tris-HCl, pH 7.2) or varying pH at a fixed alkali metal cation concentration (0.1 M) were measured. The same type of membranes were also mounted in conventional electrode body and their potentiometric responses to varying pH at a fixed alkali metal cation concentration (0.1 M) were measured. The complex formation constants of the ligand could be calculated from the calibration plots of the relative absorbance vs. the activity ratios of cation and proton ($a_{M^+}/a_{H^+}$) and of the emf vs. pH. It was confirmed that the ratio values of the complex formation constants for the primary and interfering ions are closely related to the experimental selectivity coefficients of ISEs.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.21-27
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• 2022

Flexible pressure sensor was developed using low-cost conductive graphite as printed electronics. Flexible pressure sensors are attracting attention as materials to be used in future industries such as medical, games, and AI. As a result of evaluating various electromechanical properties of the printed electrode for flexible pressure sensors, it showed a constant resistance change rate in a maximum tensile rate of 20%, 30° tension/bending, and a simple pulse test. A more appropriate matrix pattern was designed by simulating the electrodes for which this verification was completed. Utilizing the Serpentine pattern, we utilized a process that allows simultaneous fabrication and encapsulation of the matrix pattern. One side of the printed graphite electrode was O₂ plasma surface treated to increase adhesive strength, rotated 90 times, and two electrodes were made into one through a lamination process. As a result of pasting the matrix pattern prepared in this way to the wrist pulse position of the human body and proceeding with the actual measurement, a constant rate of resistance change was shown regardless of gender.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.4
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• pp.284-288
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• 2002

The authors examined the response of electrocardiogram (ECG) to Mirror carp, Cyprinus carpio of body length. The experiments were performed of three classes (10~15, 15~20 and 20~25cm) were given to fishes with an electrode inserted into their bodies and then their ECGs were recorded continuously for 30 minutes in 16-18$^{\circ}C$. The results which are divided into by day and by night and then analyzed by fishes' conditions are as follows; 1 In case of body length 10~15 cm, the average heart rate 43.4 beat/min by day and 45.9 beat/min by night, the average action potential 4.38 $mutextrm{V}$ by day and 3.64 $mutextrm{V}$ by night, in narcotism condition(0~9 min). the average heart rate 69.4 beat/min by day and 67.4 beat/min by night, the average action potential 3.82 $mutextrm{V}$ by day and 3.50 $mutextrm{V}$ by night, in stable condition(9~30 min). 2. In case of body length 15～20 cm, the average heart rate 42.2 beat/min by day and 45.4 beat/min by night, the average action potential 4.13 $mutextrm{V}$ by day and 3.95 $mutextrm{V}$ by night, in narcotism condition(0-5 min). the average heart rate 67.6 beat/min by day and 65.3 beat/min by night, the average action potential 4.58$mutextrm{V}$ by day and 4.61 $mutextrm{V}$ by night, in stable condition (5~30 min). 3. In case of body length 20～25 cm, the average heart rate 47.5 beat/min by day and 47.5 beat/min by night, the average action potential 4.81 $mutextrm{V}$ by day and 4.20 $mutextrm{V}$ by night, in narcotism condition(0-4 min). the average heart rate 67.5 bea/min by day and 64.8 beat/min by night, the average action potential 5.31 $mutextrm{V}$ by day and 4.90 $mutextrm{V}$ by night, in stable condition (4~30 min).

• Korean Journal of Animal Reproduction
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• v.7 no.2
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• pp.8-26
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• 1983

Various early pregnancy diagnostic methods have been developed in order to improve the reproductive efficiency in cow, mare, mule, sow, sheep, goat, dog, cat, rabbit, buffalo, camel, elephant, monkey, deer, lion, coipus and guinea pig. These methods include abdominal swelling, abdominal palpation, esturs cylce detection, Lupin test, gonadotropin assay, colostrum injection test, sperm motility assessment, cervical mucus viscosity test, Kaber chromagens method, estrogen test, A Scheim-Zond다 test, spectrophotometric detection of estrogen in urine and feces, boric acid crystraline formation test in urine, oxytocin injection test, diamino-oxidase test, PMSG HA test, behaviour test, Simolus iodine detection test, detection of tryptophane in urine, x-ray method, Cuboni and Lunaas method, vaginal biopsy method, Friedmann Schneider diagnostic method, electrode method, barium chloride detection method, ECG, Doptone method, ultrasound method, ultrasound scanning method, LDH method, rectal palpation method, CL palpation method, radioautography, serum creatine test, serum globulin test, chlormadine method, CAP method, Medata Do, pp.ers method, body fluid test, Plasma oCS detection method, ERIA, LHRH method, negative latex cogulation test and oestrone sulphate detection method. The most reliable methods with high a, pp.icability to farm animals such as sheep, mare, sow and cow are rectal palpation, ultrasound method and hormonal assay in blood and milk. However, they require complicated laboratory works for the early diagnosis of pregnancy and in most cases, the simple and economical methods which are described up to now need a long period of time after conception. Generally, it is possible to detect pregnancy after one estrus cycle, even though it varies depending on the species of animals. For improvement of the reproductive efficiency, it is required to develop a more accurate, economical, simple and early detectable method. It is anticipated that the result of a study on the detection method of EPF(early pregnancy factor) would be a, pp.icable to various animals within 6 hours after conception.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.166-173
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• 2006

In this study, a probe array has been developed for use in a data storage device that is based on scanning probe microscope (SPM) and MEMS technology. When recording data bits by poling the PZT thin layer and reading them by sensing its piezoresponse, commercial probes of which the tip heights are typically shorter than $3{\mu}m$ raise a problem due to the electrostatic forces occurring between the probe body and the bottom electrode of a medium. In order to reduce this undesirable effect, a poly-silicon probe with a high aspect-ratio tip was fabricated using a molding technique. Poly-silicon probes fabricated by the molding technique have several features. The tip can be protected during the subsequent fabrication processes and have a high aspect ratio. The tip radius can be as small as 15 nm because sharpening oxidation process is allowed. To drive the probe, electrostatic actuation mechanism was employed since the fabrication process and driving/sensing circuit is very simple. The natural frequency and DC sensitivity of a fabricated probe were measured to be 18.75 kHz and 16.7 nm/V, respectively. The step response characteristic was investigated as well. Overshoot behavior in the probe movement was hardly observed because of large squeeze film air damping forces. Therefore, the probe fabricated in this study is considered to be very useful in probe-based data storages since it can stably approach toward the medium and be more robust against external shock.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.84-94
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• 2007

In order to collect information on local distribution of conductivity and permittivity underneath a scan probe, we developed a multi-frequency trans-admittance scanner (TAS). Applying a sinusoidal voltage with variable frequency on a chosen distal part of a human body, we measure exit currents from 320 grounded electrodes placed on a chosen surface of the subject. The electrodes are packaged inside a small and light scan probe. The system includes one voltage source and 17 digital ammeters. Front-end of each ammeter is a current-to-voltage converter with virtual grounding of a chosen electrode. The rest of the ammeter is a voltmeter performing digital phase-sensitive demodulation. Using resistor loads, we calibrate the system including the scan probe to compensate frequency-dependent variability of current measurements and also inter-channel variability among multiple. We found that SNR of each ammeter is about 85dB and the minimal measurable current is 5nA. Using saline phantoms with objects made from TX-151, we verified the performance of the lesion estimation algorithm. The error rate of the depth estimation was about 19.7%. For the size estimate, the error rate was about 15.3%. The results suggest improvement in lesion estimation algorithm based on multi-frequency trans-admittance data.