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51.
D. T. Thao I. S. Kim H. H. Na S. M. Jung J. Y. Shim 《The International Journal of Advanced Manufacturing Technology》2014,73(5-8):837-847
Gas metal arc (GMA) welding process has widely been employed due to the wide range of applications, cheap consumables, and easy handling. In order to achieve a high level of welding performance and quality, a suitable model is required to investigate the characteristics of the effects of process parameters on the bead geometry in the GMA welding process. This paper is to represent new algorithms to predict process parameters on top-bead width in robotic GMA welding process. The models have been developed, linear, curvilinear, and intelligent model, based on full factorial design with two replications. Regression analysis was employed for optimization of the coefficients of linear and curvilinear models, while genetic algorithm (GA) was utilized to estimate the coefficients of an intelligent model. Not only the fitting of these models was checked and compared by using a variance test (analysis of variance (ANOVA)) but also the prediction on top-bead width using the developed models was carried out based on the additional experiments. The developed models were employed to investigate the characteristic between process parameters and top-bead width. Resulting solutions and graphical representation showed that the intelligent model developed can be employed for prediction of bead geometry in GMA welding process. 相似文献
52.
A shape changing material (SCM) morphs its shape upon external stimulus, and it offers a design of complex 3-dimensional structures remotely, which can be potentially useful for biomedical tools, drug delivery, and soft robotics. To actuate such structures through a physicochemical stimulus, stimuli-responsive materials have been studied over the past few decades. Several SCMs have been reported by combining novel stimuli-responsive materials, micropatterning techniques and a unique actuation cue. In this review, we introduce a recent development in SCMs within the aspects of their materials and structures to describe how the materials can be designed and actuated on demand. Finally, we discuss the future direction and challenges for SCMs as physicochemically-powered actuators. 相似文献
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54.
Seong-O Shim 《Microscopy research and technique》2022,85(3):940-947
Shape from focus (SFF) is a technique to recover the shape of an object from multiple images taken at various focus settings. Most of conventional SFF techniques compute focus value of a pixel by applying one of focus measure operators on neighboring pixels on the same image frame. However, in the optics with limited depth of field, neighboring pixels of an image have different degree of focus for curved objects, thus the computed focus value does not reflect the accurate focus level of the pixel. Ideally, an accurate focus value of a pixel needs to be measured from the neighboring pixels lying on tangential plane of the pixel in image space. In this article, a tangential plane on each pixel location (i, j) in image sensor is searched by selecting one of five candidate planes based on the assumption that the maximum variance of focus values along the optical axis is achieved from the neighborhood lying on tangential plane of the pixel (i, j). Then, a focus measure operator is applied on neighboring pixels lying on the searched plane. The experimental results on both the synthetic and real microscopic objects show the proposed method produces more accurate three-dimensional shape in comparison to conventional SFF method that applies focus measures on original image planes. 相似文献
55.
Food Science and Biotechnology - One-hundred-and-seventy-nine Staphylococcus aureus strains, collected from a total of 825 resident and household item samples in Korean homes nationwide, were... 相似文献
56.
Bombi Lee Jinhee Park Sunoh Kwon Mijung Yeom Bongjun Sur Insop Shim Hyejung Lee Suk Hoo Yoon Dong-Myong Jeong Dae-Hyun Hahm 《Food science and biotechnology》2012,21(3):723-729
The aim of this study was to investigate the effects of sowthistle (Ixeris dentata, IXD) on development and expression of nicotine-induced locomotor sensitization and underlying neuronal activation reflected by c-Fos expression in rats. Rats were pretreated with IXD 30 min before a daily injection of nicotine during an 8-day development phase and then challenged with nicotine after a 6-day withdrawal period. In another set of experiments, same IXD doses were administered once 30 min before nicotine challenge. Daily IXD treatment during development phase was not effective in blocking nicotine-induced locomotor sensitization in rats. However, a single IXD treatment after the development and withdrawal periods of nicotine sensitization significantly alleviated sensitized locomotor behavior on day 15. These behavioral results were coincident with significant inhibition of nicotineinduced c-Fos expression in the nucleus accumbens. These results indicated that IXD pretreatment significantly blocked the expression, but not the development of nicotine-induced locomotor sensitization in rats. 相似文献
57.
Yim Sang Ryun Park Ga Young Lee Kwang Won Chung Myung-Sub Shim Soon-Mi 《Food science and biotechnology》2017,26(1):293-298
Food Science and Biotechnology - The objectives of this study was to examine the amount of total arsenic and arsenic speciation in different types of rice from two areas in Korea using inductively... 相似文献
58.
Won-Seok Ko Ju-Young Oh Jae-Hyeok Shim Jin-Yoo Suh Woo Young Yoon Byeong-Joo Lee 《International Journal of Hydrogen Energy》2014
Inter-diffusion between vanadium and palladium coating layers in vanadium-based hydrogen separation membranes is investigated by using a computational approach based on first-principles calculations and semi-empirical atomistic simulations, paying attention to the surface stability and the prevention of the degradation of hydrogen permeability. It is found that the governing mechanism of the inter-diffusion is the grain boundary diffusion, and therefore a diffusion barrier based on the grain boundary segregation of impurities can be an efficient way to inhibit the inter-diffusion that causes the degradation. An interesting aspect in previous experimental works that showed a good resistance to the inter-diffusion by an addition of a trace amount of yttrium is discussed from the view point of the grain boundary segregation. An experiment that proves the validity of the present alloy design scheme (inhibition of inter-diffusion using grain boundary segregation) is carried out, and a process to maximize the sustainability of the membrane is also proposed. 相似文献
59.
In this article the effects of moisture on a novel epoxy molding compound, including the mechanical properties, temperature transition, and thermal degradation behavior, are studied. The experimental results reveal that the absorbed water acts predominantly as a crazing agent, continuously decreasing the mechanical strength with the time in water. The glass-transition temperature decreases at the early stage and is finally equilibrated. The thermal degradation behavior of the materials is not greatly influenced by the hydrothermal age. The decomposition of samples in oxygen is composed of two independent steps: the thermal degradation and oxidation at high temperature. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2253–2259, 2001 相似文献
60.