• Smart Structures and Systems
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• v.23 no.5
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• pp.429-447
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• 2019

The present study analyzed free vibration of the three-layered micro annular/circular plate which its core and face sheets are made of saturated porous materials and FG-CNTRCs, respectively. The structure is subjected to magneto-electric fields and magneto-electro-mechanical pre loads. Mechanical properties of the porous core and also FG-CNTRC face sheets are varied through the thickness direction. Using dynamic Hamilton's principle, the motion equations based on MCS and FSD theories are derived and solved via GDQ as an efficient numerical method. Effect of different parameters such as pores distributions, porosity coefficient, pores compressibility, CNTs distribution, elastic foundation, multi-physical pre loads, small scale parameter and aspect ratio of the plate are investigated. The findings of this study can be useful for designing smart structures such as sensor and actuator.

• Journal of Sensor Science and Technology
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• v.30 no.3
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• pp.185-189
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• 2021

Herein, we propose a functional polymer cantilever to enhance maturation and contractile force of cardiomyocytes. The proposed cantilever consists of a surface-patterned polymer substrate and silver nanowires (AgNWs). The AgNWs are transferred to the PDMS substrate using conventional molding techniques. This thin metallic surface significantly improves the adhesion of cardiomyocyte on the surface-patterned PDMS with the hydrophobic characteristics. In addition, the use of AgNWs improves the visibility of the conducting PDMS substrate for the observation of cardiomyocyte through an inverted microscope. The AgNWs also assist in synchronizing each cardiomyocyte to maximize its contractile force.

• Journal of Sensor Science and Technology
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• v.30 no.3
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• pp.125-130
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• 2021

In this study, the degree of alignment of polymer microfibers produced by electrospinning using a rotating water collector was evaluated. Aligned micro- and nano-fibers are required in various practical applications involving anisotropic properties. The degree of fiber alignment has many significant effects; hence, and accurate quantitative analysis of fiber alignment is necessary. Therefore, this study developed a simple and efficient method based on two-dimensional fast Fourier transform, followed by ellipse fitting. As a demonstrative example, the polymer microfibers were electrospun on the rotating water collector as the alignment of microfibers can be easily controlled. The analysis shows that the flow velocity of the liquid collector significantly affects the electrospun microfiber alignment, that is, the higher the flow velocity of the liquid collector, the greater is the degree of microfiber alignment. This method can be used for analyzing the fiber alignment in various fields such as smart sensors, fibers, composites, and textile engineering.

• Journal of Ceramic Processing Research
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• v.13 no.spc2
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• pp.359-362
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• 2012

We have employed Kelvin force microscopy (KFM) system to measure the potential change of a single SnO2 nanowire which had been synthesized on the Au thin film by a thermal process. By using the KFM probing technique, Rh coated conducting cantilever can approach a single SnO2 nanowire in nano scale and get the potential images with oscillating AC bias between Au electrode and cantilever. Also, during imaging the potential status, we controlled the concentration of oxygen in measuring chamber to change the ionosorption rate. From the results of such experiments, we verified that the surface potential as well as doping type of a single SnO2 nanowire could be changed by oxygen ionosorption.

• Advances in nano research
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• v.16 no.2
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• pp.201-215
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• 2024

The present research study emphasizes the utilization of mathematical simulation on a nanoelectromechanical systems (NEMS) sensor to facilitate the detection of injuries in players and equipment. Specifically, an investigation is conducted on the thermal buckling behavior of a small-scale truncated conical, cylindrical beam, which is fabricated using porous functionally graded (FG) material. The beam exhibits non-uniform characteristics in terms of porosity, thickness, and material distribution along both radial and axial directions. To assess the thermal buckling performance under various environmental heat conditions, classical and first-order nonlocal beam theories are employed. The governing equations for thermal stability are derived through the application of the energy technique and subsequently numerically solved using the extended differential quadratic technique (GDQM). The obtained results are comprehensively analyzed, taking into account the diverse range of effective parameters employed in this meticulous study.

• Science of Emotion and Sensibility
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• v.24 no.4
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• pp.129-138
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• 2021

This study aimed to determine the effects of the shape and attachment position of stretchable textile sensors coated with carbon nanotube on their performance when used to measure children's joint movements. Moreover, the child-safe requirements for fabric motion sensors are established. The child participants were advised to wear integrated clothing equipped with the sensors of various shapes (rectangular and boat-shaped) and attachment positions (at the knee and elbow joints or 4 cm below the joints). The voltage change induced by the elongation and contraction of the fabric sensors was determined for arm and leg flexion-extension motions at 60 deg/s (three measurements of 10 repeats each for 60°and 90°angles, for a total of 60 repetitions). Their dependability was determined by comparing the fabric motion sensors to the associated acceleration sensors. The experimental results indicate that the rectangular-shaped sensor affixed 4 cm below the joint is the most effective fabric motion sensor for measuring children's arm and leg motions. In this study, we designed a textile sensor capable of tracking children's joint motion and analyzed the sensor shape and attachment position on motion sensing clothing. We demonstrated that flexible fabric sensors integrated into garments may be used to detect the joint motions of the human body.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.189-189
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• 2015

Plasmonics, sensor, field effect transistors, solar cells 등 다양한 적용분야를 가지는 실리콘 구조체는 제작공정에 의해 전기적 및 광학적 특성이 달라지기 때문에 적합한 나노구조 제작방법이 요구되고 있다. 나노구조체 제작방법으로는 Photo lithography, Extreme ultraviolet lithography (EUV), Nano imprinting lithography (NIL), Block copolymer (BCP) 방식의 방법들이 연구되고 있으며, 특히 BCP는 direct self-assembly 특성을 가지고 있으며 가격적인 면에서도 큰 장점을 가진다. 하지만 BCP를 mask로 사용하여 식각공정을 진행할 경우 BCP가 버티지 못하고 변형되어 mask로서의 역할을 하지 못한다. 이러한 문제를 해결하기 위하여 본 논문에서는 BCP와 질화막을 이용한 double mask 방법을 사용하였다. 기판 위에 BCP를 self-assembly 시키고 mask로 사용하여 hole 부분으로 노출된 기판을 Ion gun을 통해 질화 시킨 후에 BCP를 제거한다. 기판 위에 hole 모양의 질화막 표면은 BCP와 다르게 etching 공정 중 변형되지 않는다. 이러한 질화막 표면을 mask로 사용하여 pillar pattern의 실리콘 나노구조체를 제작하였다. 질화막 mask로 사용되는 template은 PS와 PMMA로 구성된 BCP를 사용하였다. 140kg/mol의 polystyrene과 65kg/mol의 PMMA를 톨루엔으로 용해시키고 실리콘 표면 위에 spin coating으로 도포하였다. Spin coat 후 230도에서 40시간 동안 열처리를 진행하여 40nm의 직경을 가진 PS-b-PMMA self-assembled hole morphology를 형성하였다. 질화막 형성 및 etching을 위한 장비로 low-energy Ion beam system을 사용하였다. Reactive Ion beam은 ICP와 3-grid system으로 구성된 Ion gun으로부터 형성된다. Ion gun에 13.56 MHz의 frequency를 갖는 200W 전력을 인가하였다. Plasma로부터 나오는 Ion은 $2{\Phi}$의 직경의 hole을 가지는 3-grid hole로 추출된다. 10~70 voltage 범위의 전위를 plasma source 바로 아래의 1st gird에 인가하고, 플럭스 조절을 위해 -150V의 전위를 2nd grid에 인가한다. 그리고 3rd grid는 접지를 시켰다. chamber내의 질화 및 식각가스 공급은 2mTorr로 유지시켰다. 그리고 기판의 온도는 냉각칠러를 이용하여 -20도로 냉각을 진행하였다. 이와 같은 공정 결과로 100 nm 이상의 높이를 갖는 40 nm직경의 균일한 Silicon pillar pattern을 형성 할 수 있었다.

• Membrane Journal
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• v.21 no.2
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• pp.163-170
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• 2011

Membrane fouling control in water treatment may be the main obstacle for wider implementation and lower cost. A novel fluorescent spectroscope sensor device for membrane fouling integrity monitoring has been developed and evaluated in this study. PSf membranes for water treatment has been fabricated with three types of organic fluorescent materials, OB, FP, KCB. The fluorescent signal from membrane surface was analyzed throughout the filtration process. It was found that the fluorescent signal due to the membrane fouling decreased and the developed device is reliable for membrane fouling monitoring.

• The Journal of Information Technology
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• v.10 no.2
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• pp.37-45
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• 2007

The multiple-ability which the structure and the physical properties which the carbon or scull tube are unique show the applicability is superior in the plane indication element which is an indispensability of information communications apparatus, the stubbornness memory element, 2nd change of air and the rough copy dosage [khay] plaque seater, the hydrogen store material and the chemical sensor back and it has the possibility which will pass over the limit which the element of existing has. from the present paper it compared in the steel and only 10 the boat it did and it analyzed against an energy storage space voluntary application and developmental apply the carbon or scull tube trend in order about under researching the effective energy storage element it could be appeared, the technique of the strong carbon nano tube. 1. The hazard which embodies the energy storage element which uses the carbon or scull tube it follows in the function which stands and CNT of the structure which is various is necessary. 2. CNT fabrications of each one must precede possible not only must be each Cabinet conference circumstances quality gain and loss. 3. The structural control of syntheses, length controls, diameter controls and the metal - CNT junction control backs of quality CNT must precede. Applies the hereafter carbon or the scull tube in the various element with the primary preceding base technique for the structural plan technique of the carbon or scull tube to be certainly established, it does, secondarily the various element functional control technique which uses the carbon or scull tube is researched and will do.

• Korean Journal of Materials Research
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• v.21 no.9
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• pp.486-490
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• 2011

Nano-indium-coated ZnO:In thick films were prepared by a hydrothermal method. ZnO:In gas sensors were fabricated by a screen printing method on alumina substrates. The gas sensing properties of the gas sensors were investigated for hydrocarbon gas. The effects of the indium concentration of the ZnO:In gas sensors on the structural and morphological properties were investigated by X-ray diffraction and scanning electron microscopy. XRD patterns revealed that the ZnO:In with wurtzite structure was grown with (1 0 0), (0 0 2), and (1 0 1) peaks. The quantity of In coating on the ZnO surface increased with increasing In concentration. The sensitivity of the ZnO:In sensors was measured for 5 ppm $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature by comparing the resistance in air with that in target gases. The highest sensitivity to $CH_4$ gas and $CH_3CH_2CH_3$ gas of the ZnO:In sensors was observed at the In 6 wt%. The response and recovery times of the 6 wt% indiumcoated ZnO:In gas sensors were 19 s and 12 s, respectively.