Experimental Mechanics in Nano and Biotechnology

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Authors: Jae Jong Lee, Seung Woo Lee, Hyun Taek Cho, Gee Hong Kim, Kee Bong Choi
Abstract: The contact-based nanoimprinting lithography (NIL), such as thermal and/or UV nano-imprint, has been well known as one of the next generation lithography alternatives. Especially, the UV nanoimprinting lithography technology has the advantages in terms of process simplicity, low cost, high replication fidelity, and relatively high throughput. The UV nanoimprinting lithography tool is built with the characteristic functions like a self-alignment wafer stage, a nanoimprinting head unit, an alignment system for multi-layer process, stamp/wafer chucking units, releasing unit, and anti-vibration unit, etc. This UV-NIL tool is comprised of UV light source using mercury lamp, ultra-fine XY stage with nano-level positioning accuracy, and self-adjusting flexure stage. The self-adjusting stage has the capability to control 6- axes positions of wafer-holder. The UV-NIL tool can be used for fabrication of some functional nanostructure-patterns i.e. nanosensor electrodes, optical grating patterns and 70nm rectangle patterns.
Authors: Beom Goo Lee, Yeon Ho Jeong, Dong Ha Cho, Kang Yol Lee, Wie Soo Kang
Abstract: It is investigated whether ginseng can be milled into super fine powder below 50μm, changing the circumferential velocity of impeller of a turbo mill(100, 110 and 120m/s). The mean particle size is 113.3μm in control but is decreased abruptly into 11.9μm at 120m/s. The largest particle diameter at 97% of volume distribution is reduced into below 32μm at 120m/s from below 725μm at control. The particle size distribution between d(0.1) and d(0.9) is 334μm at control, but is decreased into less than 26μm in all conditions after milling. It shows that ginseng can be milled into super fine powder by the turbo mill, which has the narrow particle size distribution.
Authors: Young Eun Yoo, Young Ho Seo, Seong Kon Kim, Tai Jin Je, Doo Sun Choi
Abstract: An injection molding technology is developed to replicate pillars in micro/nano scale on the thin plastic substrate. Two types of pillar are to be replicated and one is square type of 10um x 10um, the other is circular type whose diameter is in range of 100 nm ~ 300 nm. For both types of the pillars, the height is about 250 nm. A pattern master is first fabricated on the photo resist(PR) layer spin coated to about 250nm of thickness on chrome/quartz plate by patterning e-beam writing and then developing the PR. The patterns on the PR master are transferred by nickel electro-plating to fabricate rigid nickel stamper. Using this nickel stamper, a substrate with nano pillars on its surface is injection molded by optimizing the conditions to fabricate DNA separating chip.
Authors: Kwang Suck Boo, Hyun Ho Yook, Jong Il Lee, Woo Seong Che
Abstract: This paper describes a method to detect leaks on the surface of a wheel rim manufactured by aluminum die casting and forging. Leaks in the wheel rim may be caused by temperature gradient differences during the cooling period, impurities, or flowing air bubbles in the die casting process. We developed a new low-cost approach to detect leaks that only required a short inspection time by observing the movement of soap bubbles on the wheel rim surface. We designed new light sources to minimize mirror image effects and irregular luminance distributions on the curved wheel rim surface. A preprocessing procedure for image processing was also developed to determine the bubble configurations using threshold and morphology techniques. A series of experiments were conducted to evaluate the performance of the inspection system. The results demonstrated that leaks generated during the wheel rim manufacturing process could be accurately detected even under various environmental lighting conditions.
Authors: Hoi Yan Cheung, Alan Kin Tak Lau
Abstract: With the strong emphasis on environmental awareness, it has brought much attention in the development of recyclable and environmentally sustainable composite materials since the last decade. Environmental legislation as well as consumer demand in many countries is increasing the pressure on manufacturers of materials and end-products to consider the environmental impact of their products at all stages of their life cycle, including recycling and ultimate disposal. Silk fibers, spun out from silkworm cocoons, consist of a fibroin core surrounded by a protein layer called "sericin", and these fibers are biodegradable and highly crystalline. It has been known that these fibers have higher tensile strength and are more predictable in failure than glass and synthetic organic fibers. Recently, few preliminary studies have reported that the use of these silks, as microreinforcements to replace un-recyclable carbon and glass fibers for polymeric-based structural composite materials can enhance their mechanical and thermal properties, with reducing the amount of un-decomposable wastes and pollutants. In this paper, the mechanical properties of silk-based epoxy composites formed by different controlled manufacturing parameters are elaborately studied.
Authors: C.N. Lin, Yu Yong Jiao, Q.S. Liu
Abstract: In the construction of railways in western part of China, more and more long tunnels have been excavated these years, and several ones are under construction at the moment. Because of the complex geologies like faults, fractured zones, karst cavities as well as water bearing formations, the stability and safety of tunnels have been challenging topics in the construction process. In this regard, the advance knowledge of the location, size, and spatial information of the uncertainties ahead of the face is very important to the contractors. In this paper, by using the Tunneling Seismic Prediction (TSP) technique, site experiments are performed to predict hazardous formations ahead of face in a railway tunnel. Through interpretation of the testing data, the wave velocities and the mechanical parameters of the surrounding rock are obtained, and the faults/fractures are recognized. The study shows that compared to time-consuming core drilling method, the wave reflection based TSP method can predict major uncertain formations in long range ahead of the face in short time. The downtime, as we know, is one of the key factors in speeding the tunnel construction. For the prediction accuracy, the TSP technique is able to provide enough information due to its multiple proof-test procedure.
Authors: Dong Ju Yang, Sung Jin Song, Hak Joon Kim, Wen Wu Wang, Sung Duk Kwon
Abstract: Titanium-nitride (TiN) ceramic coatings are widely utilized to extend the lifetime of mechanical parts under severely abrasive conditions and in lubrication environment. Since ceramic layers coated on machinery components inevitably experience the changes in their properties, it is necessary to evaluate the characteristics of ceramic coating layers nondestructively for the reliable use of coated components and the remaining life prediction. For this purpose, in the present study, the ultrasonic backward radiation technique is applied to evaluate very thin TiN ceramic layers coated on AISI 1045 steel and austenitic 304 steel substrates. In this study, very interesting behaviors are revealed from the interrogated TiN ceramic coated specimens. The sliding loading in the abrasive wear regime increases the peak amplitude of the profile. However, the sliding loading large enough to produce scuffing finally decreases the peak amplitude of the profile while the peak angle increases.
Authors: Fu Qiang He, Wen Wang, Zi Chen Chen
Abstract: The visual inspection system was developed for defects detection on leather surfaces, which is an important component of automatic CAD/CAM cutting systems. The main functions of the system are quality control and raw material cutting. An efficient algorithm, which combines multiresolution approach, energy and entropy matrices, is presented for detection of defects embedded in leather surface images. A wavelet band selection procedure was developed to automatically determine the number of resolution levels and decompose subimages for the best discrimination of defects and removals of repetitive texture patterns in the image. An adaptive binary thresholding is then used to separate the defective regions from the uniform gray-level background in the restored image. The proposed methodology is able to efficiently detect several types of defects that current approaches cannot detect, and is fast enough to be used for real-time leather inspection.
Authors: Ik Keun Park, Yong Kwon Kim, Won Joon Song, Yong Sang Cho
Abstract: Conventional non-destructive techniques for inspection of weld in pipelines require significant test time and high cost. In order to overcome these drawbacks in conventional NDT techniques, various techniques using ultrasonic guided waves have been developed and applied to the pipeline inspection. Recently, a fast calculation technique for guided wave propagation using a semi-analytical finite element method (SAFEM), PIPE WAVE ver.1.0, has been developed by T. Takahiro et al [1]. In this paper, the calculation of torsional mode propagation in a pipe using PIPE WAVE ver. 1.0 is introduced as a preliminary study and the application of the torsional mode of ultrasonic guided waves to long range pipe inspection is presented.. The characteristics and setup of a long range guided wave inspection system and experimental results in pipes of various diameters are introduced. The experimental results in mock-up pipes with cluster type detects show that the limit of detectable wall thickness reduction with this guided wave system is 2~3% in the pipe cross section area and the wall thickness reduction of 5% in cross section area can be detected when actual detection level is used. Therefore, the applicability of the ultrasonic guided wave technique to long range pipeline inspection for wall thickness reduction is verified.
Authors: Hyun Mook Kim, Tae Hun Lee, Kyung Young Jhang
Abstract: This paper proposes a non-contact single-mode guided wave technique, where the laser beam illuminated through the arrayed line slits is used as the transmitter, and the air-couple transducer is used as the receiver. The line-arrayed laser illumination has a wavelength-matching effect that can generate only a few modes. The air-coupled transducer detects the leaky wave of the propagated guided wave, and by tuning the detection angle of the transducer we can detect the selected single mode. The proposed technique is fully non-contact and is possible to avoid difficulty in the mode identification. The experimental results for a 1-mm thick aluminum plate prove the usefulness of the proposed method, and most especially, it shows that the method is powerful in the generation and detection of anti-symmetric modes of the lowest order.

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