• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.38-48
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• 2014

In this paper, a design of Signal Processing Analog Front-End IC for Automotive Piezo-Resistive Type Pressure Sensor is presented. In modern society, as the car turns to go from mechanical to electronic technology, the accuracy and reliability of electronic parts required importantly. In order to improve these points, Programmable Gain Amplifier (PGA) amplifies the received signal in accordance with gain for increasing the accuracy after PRT Sensor is operated to change physical pressure signals to electrical signals. The signal amplified from PGA is processed by Digital blocks like ADC, CMC and DAC. After going through this process, it is possible to determine the electrical signal to physical pressure signal. As processing analog signal to digital signal, reliability and accuracy in Analog Front-End IC is increased. The current consumption of IC is 5.32mA. The die area of the fabricated IC is $1.94mm{\times}1.94mm$.

• Science of Emotion and Sensibility
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• v.24 no.2
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• pp.49-56
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• 2021

In this study, we investigated the necessary mechanical properties of conductive multifilament yarns for fabricating the electrodes of biosignal measurement pressure and stretch textile sensors using embroidery. When electrodes and circuits for smart wearable products are produced through the embroidery process using conductive multifilament yarns, unnecessary material loss is minimized, and complex electrode shapes or circuit designs can be produced without additional processes using a computer embroidering machine. However, because ordinary missionary threads cannot overcome the stress in the embroidery process and yarn cutting occurs, herein, we analyzed the S-S curve, thickness, and twist structure, which are three types of silver-coated multifilament yarns, and measured the stress in the thread of the embroidery simultaneously. Thus, the required mechanical properties of the yarns in the embroidery process were analyzed. In the actual sample production, cutting occurred in silver-coated multifilament rather than silver-coated polyamide/polyester, which showed the lowest S-S curve. In the embroidery process, the twist was unwound through repetitive vertical movement. Further, we fabricated a piezoresistive pressure/tension sensor to measure gauge factor, which is an index for measuring biological signals. We confirmed that the sensor can be applied to the fabrication of embroidery electrodes, which is an important process in the mass production of smart wearable products.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.233-243
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• 2006

The aim of this study was to investigate the relationship between the C-factor and shrinkage strain values of composite resin and examine the strain values in different incremental filling techniques. Experiment consisted two aims. First, we compared with strain value in two different C-factors(3.7 and 1.0). Second, we examined the strain values in three different filling techniques. The results of the present study can be summarized as follows : 1. High C-factor groups showed higher contraction stress values than low C-factor groups at 900 sec after polymerization. 2. Hybrid resin showed higher contraction stress values than flowable resin in high C-factor cavities. But contraction stress was not revealed significant difference between hybrid resin and flowable resin in low C-factor cavities (P>0.05). 3. Bulk felling with hybrid resin(Group 1) showed high contraction stress and lining with flowable resin followed hybrid resin (Group 5) showed lower contraction stress. 4. Contraction stress were increased during 900 sec after polymerization in high C-factor groups but decreased gradually after 900 sec. 5. Low C-factor groups showed tight marginal seal between resin and cavity wall but high C-factor groups showed gaps formed between resin and cavity wall in part. On the basis above results, layering techniques in high C-factor cavity showed advantages in reducing contraction stress and gap formation between cavity wall and resin restoration.

• Science of Emotion and Sensibility
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• v.22 no.1
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• pp.15-22
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• 2019

The purpose of this study is to develop a strain sensor based on a nanoweb by applying electrical conductivity to a polyurethane nanoweb through the use of Graphene. For this purpose, 1% Graphene ink was pour-coated on a polyurethane nanoweb and post-treated with PDMS (Polydimethylsiloxane) to complete a wearable strain sensor. The surface characteristics of the specimens were evaluated using a field emission scanning electron microscope (FE-SEM) to check whether the conductive material was well coated on the surface of the specimen. Electrical properties of the specimens were measured by using a multimeter to measure the linear resistance of the specimen and comparing how the line resistance changes when 5% and 10% of the specimens are tensioned, respectively. In order to evaluate the performance of the specimen, the gauge factor was obtained. The evaluation of the clothing was performed by attaching the completed strain sensor to the dummy and measuring the respiration signal according to the tension using MP150 (Biopac system Inc., USA) and Acqknowledge (ver. 4.2, Biopac system Inc., U.S.A.). As a result of the evaluation of the surface characteristics, it was confirmed that all the conductive nanoweb specimen were uniformly coated with the Graphen ink. As a result of measuring the resistance value according to the tensile strength, the specimen G, which was treated with just graphene had the lowest resistance value, the specimen G-H had the highest resistance value, and the change of the line resistance value of the specimen G and the specimen G-H is increased to 5% It is found that it increases steadily. Unlike the resistance value results, specimen G showed a higher gauge rate than specimen G-H. As a result of evaluation of the actual clothes, the strain sensor made using the specimen G-H measured the stable peak value and obtained a signal of good quality. Therefore, we confirmed that the polyurethane nanoweb treated with Graphene ink plays a role as a breathing sensor.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.363.2-363.2
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• 2016

Stretchable strain sensors are becoming essential in diverse future applications, such as human motion detection, soft robotics, and various biomedical devices. One of the well-known approaches for fabricating stretchable strain sensors is to embed conductive nanomaterials such as metal nanowires/nanoparticles, graphene, conducting polymer and carbon nanotubes (CNTs) within an elastomeric substrate. Among various conducting nanomaterials, CNTs have been considered as important and promising candidate materials for stretchable strain sensors owing to their high electrical conductivity and excellent mechanical properties. In the past decades, CNT-based strain sensors with high stretchability or sensitivity have been developed. However, CNT-based strain sensors which show both high stretchability and sensitivity have not been reported. Herein, highly stretchable and sensitive strain sensors were fabricated by integrating single-walled carbon nanotubes (SWNTs) and nylon textiles via vacuum-assisted spray-layer-by-layer process. Our strain sensors had high sensitivity with 100 % tensile strain (gauge factor ~ 100). Cyclic tests confirmed that our strain sensors showed very robust and reliable characteristic. Moreover, our SWNTs-based strain sensors were easily and successfully integrated on human finger and knee to detect bending and walking motion. Our approach presented here might be route to preparing highly stretchable and sensitive strain sensors with providing new opportunity to realize practical wearable devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.6
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• pp.470-474
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• 2001

This paper describes the fabrication and characteristics of CrN thin-film type pressure sensors, in which the sensing elements were deposited on SuS. 630 diaphragm by DC reactive magnetron sputtering in an argon-nitride atmosphere(Ar-(10%)N$_2$). The optimized condition of CrN thin-film sensing elements was thickness range of 3500$\AA$ and annealing condition(300$\^{C}$, 3 hr) in Ar-10%N$_2$ deposition atmosphere. Under optimum conditions, the CrN thin-films for strain gauges is obtained a high resistivity, ρ=1147.65 $\mu$Ωcm, a low temperature coefficient of resistance, TCR=186ppm/$\^{C}$ and a high temporal stability with a good longitudinal, 11.17. The output sensitivity of fabricated CrN thin-film type pressure sensors is 2.36 mV/V, 4∼20nA and the maximum non-linearity is 0.4%FS and hysteresis is less than 0.2%FS.

• Journal of Sensor Science and Technology
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• v.25 no.4
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• pp.247-251
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• 2016

Au/PDMS membranes are widely used to fabricate strain sensors which can detect input signals. An interfacial adhesion between metal films and polydimethylsiloxane (PDMS) substrates is one of the important factors determining the performance of strain sensors, in terms of robustness, reliability, and sensitivity. Here, we fabricate Au/PDMS membranes with (3-mercaptopropyl) trimethoxysilane (MPTMS) treatment. PDMS membranes were fabricated by spin-coating and the thickness was controlled by varying the spin rates. Au electrodes were deposited on the PDMS membrane by metal sputtering and the thickness was controlled by varying sputtering time. Owing to the MPTMS treatment, the interfacial adhesion between the Au electrode and the PDMS membrane was strengthened and the membrane was highly transparent. The Au electrode, fabricated with a sputtering time of 50 s, had the highest gauge factor at a maximum strain of ~0.7%, and the Au electrode fabricated with a sputtering time of 60 s had the maximum strain range among sputtering times of 50, 60, and 120 s. Our technique of using Au/PDMS with MPTMS treatment could be applied to the fabrication of strain sensors.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.677-689
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• 1998

In relation to concentrically loaded compression, this research is to describe, analyze, and evaluate the design strength in steel stud. The similarity and difference among load and resistance factor design specification for cold-formed steel structural members (AISI), cold-formed thin gauge members and sheeting (EC3 part 1.3), and German draft (DASt-Richtlinie 016) are introduced, discussed, and systematically evaluated. Especially, the effective width and global instability problems (flexural buckling and torsional flexural buckling) are here implied in this research. The design axial strength by dual standards (AISI and EC3) is calculated and compared using the example.

• The Journal of Asian Finance, Economics and Business
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• v.3 no.4
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• pp.43-56
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• 2016

The research aims to help merchant acquiring institutions gain a better insight on what merchant establishments in the Singapore market perceive of the costs they incur due to credit card acceptance. The research attempts to study the Singapore market and establish if increased credit card usage does increase costs for the merchant establishments that accept credit cards, this will help to acquire institutions in Singapore have a better understanding of merchant perceptions and what drives or deters credit card acceptance in the Singapore market. The survey was based on an interview of merchant establishments and the views of the merchants and was not based on their financial data. As a first step, the variables used in the survey were tested for interdependence using Chi-square tests; subsequently data reduction using factor analysis was performed and finally linear regression to establish a relation between dependent and independent variables. Merchant establishment believe accepting credit cards and increasing volume is costlier compared to another form of payment, but have mixed awareness about interchange fee. It also indicated that interchange fee and cardholder benefits are independent of the merchant establishments. The study only broadly attempts to gauge merchants view if increased credit card usage has increased costs for them.

• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.607-618
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• 1993

If the centric prematurity occurs after orthodontic treatment, it creates centric slide regarded as a possible factor in the cause of temporomandibular disorder and/or postorthodontic relapse. The purpose of this study was to investigate the manner of centric prematurity and centric slide in postorthodantic patients. The 36 orthodontic patients who had been treated with edgewise appliance at least 3 mouths previously were used in this study. After recording centric relation by the leaf gauge technique, the centric prematurity and centric slide were studied using SAM2 articulator and mandibular position indicator. The results were as follows : 1. The highest percentage of centric prematurities were found on the second molars. 2. The buccal incline of the palatal cusp was the most frequent area of centric prematurities in the maxilla, while the lingual incline of the buccal cusp was the most frequent area in the mandible. 3. There were no trends in the direction of centric slide on the mandibular position indicator. 4. There were no significant differences in centric discrepancies between the premolar extraction and nonextraction group.