• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.3
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• pp.187-192
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• 2017

This paper presents an ongoing study to develop a novel pressure sensor by means of a Nano Carbon Piezoresistive Composite (NCPC). The sensor was fabricated using the 3D printing process. We designed a miniaturized cantilever-type sensor electrode to improve the pressure sensing performance and utilized a 3D printer to build a small-sized body. The sensor electrode was made of 2 wt％ MWCNT/epoxy piezoresistive nano-composite, and the sensor body was encapsulated with a pipe plug cap for easy installation to any pressure system. The piezoresistivity responses of the sensor were converted into stable voltage outputs by using a signal processing system, which is similar to a conventional foil strain gauge. We evaluated the pressure-sensing performances using a pressure calibrator in the lab environment. The 3D-printed cantilever electrode pressure sensor showed linear voltage outputs of up to 16,500 KPa, which is a 200％ improvement in the pressure sensing range when compared with the bulk-type electrode used in our previous work.

• Journal of Fashion Business
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• v.19 no.4
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• pp.92-108
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• 2015

This study aimed at developing a down jacket prototype that utilized sunlight as an alternative energy source with no air pollution. The jacket is filled with flexible solar panels and has a heat-generating function and LED function. In this study, three smart down jacket prototypes were developed, and the jacket's capabilities were demonstrated through the thermal effect on the performance test. The typical output voltage of the flexible solar panels was 6.4V. By connecting the 2 solar cell modules in series, the final output voltage was 12.8V. A battery charge regulator module was used the KA 7809 (TO-220) of 9V. Three heating pads were to be inserted into the belly of the jacket as direct thermal heating elements, and the LED module was configured, separated by a flash and an indicator. The smart down jacket was designed to prevent damage to the down pack without the individual devices' interfering with the human body's motion. Because this study provides insulation from extreme cold with a purpose, the jacket was tested for heat insulation properties of non-heating, heating on the back, heating on the abdomen, and heating on both the back and abdomen in a sitting posture in a static state. Thermal property analysis results from examining the average skin temperature, core temperature, and the temperature and humidity within clothing showed, that placing a heating element in one place was more effective than distributing the heating elements in different locations. Heating on the back was the most effective for maintaining optimal skin temperature, core temperature, and humidity, whereas heating on the abdomen was not effective for maintaining optimal skin temperature, core temperature, or humidity within clothing because of the gap between the jacket and the body.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.5
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• pp.311-317
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• 2023

An autofilter is a device that removes impurities contained in heavy fuel oil used in diesel engines of ships or power plants, and also automatically removes impurities accumulated in the filter through a reverse washing function. The reducer-integrated motor serves to rotate the filter at low speed to enable reverse automatic cleaning in the autofilter device. To achieve a low speed of 0.65 to 0.75 rpm in a reducer-integrated motor, a small motor that can operate at 97rpm at a rated voltage of 110 V and 112.5 rpm at 220 V is required. Additionally, a large gear ratio of 1/150 is required. To ensure the durability and reliability of these reducers, the strength of the gear must be evaluated at the design stage. In general, there is a limit to evaluating the stress and strain state according to the vibration characteristics acting on each gear in the driving state of the reducer through quasi-static analysis. Therefore, in this study, the operation characteristics of the auto filter's reducer-integrated motor were first analyzed using the rigid body dynamics analysis method. Then, this rigid body dynamics analysis model was extended to a flexible multibody dynamics analysis model to analyze the stress and strain states acting on each gear and evaluate the design feasibility of the gear.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.679-682
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• 2005

Negative-differential conductance (NDC) characteristics as well as negative-differential trans-conductance (NDT) characteristics have been observed in the room temperature I-V characteristics of Field-induced Inter-band Tunneling Effect Transistors (FITETs). These characteristics have been explained with inter-band tunneling physics, from which, inter-band tunneling current flows when the energy bands of degenerately doped regions align, and it does not flow when they don't. FITET is an SOI device and the body region is not directly connected to the external terminal. Therefore, Fermi energy in the body region is determined by electrical coupling among four regions - gate, source, drain and substrate. So, a quasi Fermi energy of the majority carriers in the floating body region can be changed by external voltages, and this causes the energy band movements in the body region, which determine whether the energy bands between degenerately doped junctions aligns or not. This is a key point for an explanation of NDT and NDC characteristics. In this paper, a quasi Fermi energy movement in the floating body region of FITET was investigated by a device simulation. This result was applied for the description of relation between quasi Fermi energy in the body region and external gate bias voltage.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.11
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• pp.114-122
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• 2016

EIS (Electro interstitial scan) is a non-invasive and simple method to find the physio-pathological information inferred by electric current response with respect to low direct current applied between remote sites of the body. Although a few EIS-based devices for diagnosing diabetes were commercialized, they were not successful in offering clinical validity nor in confirming diagnostic principle. In this study, we measured the voltage responses of diabetic patients and normal subjects with a commercialized EIS device to test the usefulness of EIS in screening diabetes. For this purpose, voltage was measured between pairs of electrodes contacted at both palm, both soles of the feet and left and right forehead above both eyes. After feature extraction of voltage signals, the AUC (area under the curve) between the two groups was calculated and we found that seven variables were appropriately shown above 60% of accuracy. In addition, we applied the k-NN (k-nearest neighbors) method and found that the accuracy of classification between the two groups reached the accuracy of 76.2%. This result implies that the voltage response analysis based on EIS has potential as a diabetics screening method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.345-352
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• 2017

In this paper, a unified potentiostat which can measure the current of both $O_2$-based and $H_2O_2$-based blood glucose sensors with low supply voltage of 1.0V has been designed and verified by simulations and measurements. Potentiostat is composed of low-voltage operational transconductance amplifier, cascode current mirrors and mode-selection circuits. It can measure currents of blood glucose chemical reactions occurred by $O_2$ or $H_2O_2$. The body of PMOS input differentional stage of the operational transconductance amplifier is forward-biased to reduce the threshold voltage for low supply voltage operation. Also, cascode current mirror is used to reduce current measurement error generated by channel length modulation effects. The proposed low-voltage potentiostat is designed and simulated using Cadence SPECTRE and fabricated in Magnachip 0.18um CMOS technology with chip size of $110{\mu}m{\times}60{\mu}m$. The measurement results show that consumption current is maximum $46{\mu}A$ at supply voltage of 1.0V. Using the persian potassium($K_3Fe(CN)_6$) equivalent to glucose, the operation of the fabricated potentiostat was confirmed.

• Progress in Medical Physics
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• v.17 no.2
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• pp.89-95
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• 2006

The purpose of this study was to evaluate the radiation doses during CT transmission scan by changing tube voltage and tube current, and to estimate the radiation dose during our clinical whole body $^{137}Cs$ transmission scan and high quality CT scan. Radiation doses were evaluated for Philips GEMINI 16 slices PET/CT system. Radiation dose was measured with standard CTDI head and body phantoms in a variety of CT tube voltage and tube current. A pencil ionization chamber with an active length of 100 mm and electrometer were used for radiation dose measurement. The measurement is carried out at the free-in-air, at the center, and at the periphery. The averaged absorbed dose was calculated by the weighted CTDI ($CTDI_w=1/3CTDI_{100,c}+2/3CTDI_{100,p}$) and then equivalent dose were calculated with $CTDI_w$. Specific organ dose was measured with our clinical whole body $^{137}Cs$ transmission scan and high quality CT scan using Alderson phantom and TLDs. The TLDs used for measurements were selected for an accuracy of ${\pm}5%$ and calibrated in 10 MeV X-ray radiation field. The organ or tissue was selected by the recommendations of ICRP 60. The radiation dose during CT scan is affected by the tube voltage and the tube current. The effective dose for $^{137}Cs$ transmission scan and high qualify CT scan are 0.14 mSv and 29.49 mSv, respectively. Radiation dose during transmission scan in the PET/CT system can measure using CTDI phantom with ionization chamber and anthropomorphic phantom with TLDs. further study need to be peformed to find optimal PET/CT acquisition protocols for reducing the patient exposure with same image qualify.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.5
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• pp.673-681
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• 2014

In this paper, a novel low specific on-resistance SOI LDMOS Device with P+P-top layer in the drift region is proposed and investigated using a two dimensional device simulator, MEDICI. The structure is characterized by a heavily-doped $P^+$ region which is connected to the P-top layer in the drift region. The $P^+$ region can modulates the surface electric field profile, increases the drift doping concentration and reduces the sensitivity of the breakdown voltage on the geometry parameters. Compared to the conventional D-RESURF device, a 25.8% decrease in specific on-resistance and a 48.2% increase in figure of merit can be obtained in the novel device. Furthermore, the novel $P^+P$-top device also present cost efficiency due to the fact that the $P^+$ region can be fabricated together with the P-type body contact region without any additional mask.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.3-4
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• 2009

As device process technology advances, effective channel length, the thickness of gate oxide, and supply voltage decreases. This paper describes a novel electrostatic discharge (ESD) protection device which has current feedback for high ESD immunity. A conventional Gate-Grounded NMOS (GGNMOS) transistor has only one ESD current path, which makes, the core circuit be in the safe region, so an GGNMOS transistor has low current immunity compared with our device which has current feedback path. To simulate our device, we use conventional $0.18\;{\mu}m$ technology parameters with a gate oxide thickness of $43\;{\AA}$ and power supply voltage of 1.8 V. Our simulation results indicate that the area of our ESD protection, device can be smaller than a GGNMOS transistor, and ESD immunity is better than a GGNMOS transistor.

• Nuclear Engineering and Technology
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• v.6 no.4
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• pp.253-259
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• 1974

The output signal voltage of the pulsed ionization chamber (PIC) was measured for a range of electron density (10$^{13}$ -10$^{17}$ m$^{-3}$ ) of the 3He plasmas. This experimental data was in excellent agreement with the theory including space charge effects. As an application of the PIC techniques, two-body recombination coefficients were obtained with electron densities measured from output signal voltage of the PIC. These values as a function of pressure were in good agreement with theoretical predictions and ranged from 5$\times$10$^{-14}$ to 3$\times$10$^{-13}$ (㎥/sec) at 300$^{\circ}$K for 1 to 10 atmospheric $^3$He plasma.