2,033 research outputs found
Dominance of Auger excitation in beam heating in transmission electron microscopy: Irradiation experiments and quantitative thermal analysis of α-Al2O3
No full textThe collection of uploaded files constitutes a dataset supporting our findings, titled Dominance of Auger excitation in beam heating in transmission electron microscopy: Irradiation experiments and quantitative thermal analysis of α-Al2O3, to be submitted to a scientific journal.
The co-authors are Jihye Kwon and Hyoung Seop Kim, both at Pohang University of Science and Technology (POSTECH), Republic of Kore
Constitutive modeling and finite element analysis of metastable medium entropy alloy
No full text© 2022 Elsevier B.V.In this study, the constitutive model of metastable ferrous Fe60Co15Ni15Cr10 (at%) medium entropy alloy (FeMEA) was constructed based on deformation-induced martensitic transformation (DIMT) behavior under cryogenic temperature. The crystal structure of the FeMEA gradually transformed from a single face-centered cubic (FCC) phase to a body-centered cubic (BCC) phase during deformation. The critical initiation stress criterion and the volumetric fraction evolution model were employed to describe the DIMT kinetics during uniaxial tensile testing. The flow stress model of the FCC phase as a function of the applied strain was developed using the dislocation-based hardening model, and the BCC phase behavior was evaluated based on the macroscopic behavior of the multiphase material and phase transformation kinetics. The decline in the dislocation mean free path for the FCC phase was associated with the grain refinement of the FCC phase due to the transformed BCC islands. To verify its applicability, the model was compared to the experimental data describing phase transformation kinetics and the mechanical behavior.11Nsciescopu
Finite Element Modeling of Crumpling of Metallic Thin Foil
No full textCrumpled metallic thin foils are very promising as weight-saving and energy-absorption materials that can easily be fabricated. To achieve practical industrial applications, it is necessary to improve the understanding of the process of crumpling and the mechanical behavior of crumpled materials considering their complex internal structures. Herein, two possible strategies for computational simulations of crumpled material under closed-die compression are presented for the first time. The first one entails computations performed at the scale of the foil (direct method), while the second one considers the structure as a continuum with porosity. The analysis performed shows that the continuum-based approach is more suitable for representing the macroscopic mechanical behavior of crumpled materials with the relative densities ranging from 2% to 40%. An additional benefit is the low computational cost and high efficacy of the porous continuum approach. However, the direct method is shown to be the preferable computational tool when the internal structural patterns changes need to be adequately reproduced, e.g., for a better prediction of the mechanical response under complex loading conditions.11Nsciescopu
Towards Mass Spectrometric Detection of Genomic Mutations and Polymorphism through Single-tube Transcriptional Sequencing Reaction
No full textConstitutive modeling of cellular-structured metals produced by additive manufacturing
No full text© 2022Computational modeling is essential in the development and application of metal additive manufacturing (MAM). Most materials processed by laser or electron beam MAM exhibit a characteristic cellular structure, where the cell walls contain a higher dislocation density than the cell interior. This kind of structure is believed to be responsible for the enhanced properties of structural members produced by MAM. In this study, a constitutive description of MAM materials was developed to accurately simulate their mechanical response to loading. The modeling frame was given by the dislocation density evolution, with two distinctly different dislocation densities being considered: those in cell walls and cell interiors considered as two separate ‘phases’ of the material. By employing the constitutive model developed, numerical analyses were conducted for a broad range of MAM materials - from pure metals to alloys. A comparison of the numerical simulations with experimental data for Cu and Cu-Sn from literature demonstrated that the model provides an adequate description of its uniaxial tensile properties and the dislocation density variation. In particular, the influence of the dimensions of the cellular structure and the applied strain rate is accounted for faithfully. It is suggested that the model is applicable to a broader range of MAM-processed materials as well.11Nsciescopu
Printed Stretchable Single-Nanofiber Interconnections for Individually-Addressable Highly-Integrated Transparent Stretchable Field Effect Transistor Array
No full textStretchable electronics have been spotlighted as promising next-generation electronics. In order to drive a specific unit device in an integrated stretchable device, the interconnection of the device should be placed in a desired position and addressed individually. In addition, practical stretchable interconnection requires reliable stretchability, high conductivity, optical transparency, high resolution, and fast and large-scale production. This study proposes an approach to meet these requirements. We print the single wavy polymer nanofibers (NFs) in a desired position and convert them into metal NF interconnections. The nanoscale diameter and the wavy cylindrical shape of the metal NFs are the main reasons for the reliable stretchability and the excellent transparency. Using the stretchable metal NFs and the stretchable organic semiconductor NFs, an array of all-stretchable transparent NF-field effect transistors (NF-FETs) is demonstrated. The highly integrated NF-FET array (10 FETs/mm(2)) shows uniform performance and good stability under repeated severe mechanical deformations.11Nsciescopu
GPUTucker: Large-Scale GPU-Based Tucker Decomposition Using Tensor Partitioning
No full textTucker decomposition is used extensively for modeling multi-dimensional data represented as tensors. Owing to the increasing magnitude of nonzero values in real-world tensors, a growing demand has emerged for expeditious and scalable Tucker decomposition techniques. Several graphics processing unit (GPU)-accelerated techniques have been proposed for Tucker decomposition to decrease the decomposition speed. However, these approaches often encounter difficulties in handling extensive tensors owing to their huge memory demands, which exceed the available capacity of GPU memory. This study presents an expandable GPU-based technique for Tucker decomposition called GPUTucker. The proposed method meticulously partitions sizable tensors into smaller sub-tensors, which are referred to as tensor blocks, and effectively implements the GPU-based data pipeline by handling these tensor blocks asynchronously. Extensive experiments demonstrate that GPUTucker outperforms state-of-the-art Tucker decomposition methods in terms of the decomposition speed and scalability. © 2023 Elsevier LtdFALS
Lifestyle segmentation of older Koreans: a longitudinal comparison of segments and life satisfaction
No full textPurpose Aging is a global phenomenon for many countries, and South Korea has become the fastest aging country in the world. The purpose of this study is to identify and validate a representative typology of older Koreans based on their lifestyle and value orientations. This study also makes a longitudinal comparison of these segments in two waves using similar survey data collected in 2009 and 2017 and examines any meaningful changes that occurred during the periods. Design/methodology/approach Using survey data collected from 750 older adults living in four major cities in Korea, this study conducted factor and cluster analysis to identify lifestyle segmentation of elderly Koreans. Both descriptive and mean comparison analyses are followed to characterize the segments with relevant demographic and behavioral variables. In addition, this study makes a longitudinal comparison of these segments in two waves (2009 and 2017) and examines any meaningful changes that occurred during the periods. Findings Six distinctive lifestyle segments of elderly Koreans are identified. The longitudinal comparison reveals some changes that occurred during the period. The level of importance of values and things to own has been declined during the period on most of the aspects, which can be interpreted that older Koreans become more realistic and practical. The level of life satisfaction between the two periods turned out to be similar. However, satisfaction in material comfort and health has been improved during the period, which means that the perception of their financial and physical aspects has been improved over the years. Originality/value First, based on Tempest et al.'s three grey discontinuity framework (2002), the segmentation model provides comprehensive coverage of psychological transitions experienced by older people due to economic, physical and mental discontinuities with age. Second, this might be the first longitudinal study to examine the changes in segmentation over time in terms of the lifestyle of older adults. Practically, the findings of this study provide useful insights for policymakers in developing aging-related policies as well as for marketers who are interested or currently doing business in Korea or Asian consumer markets.1
Mechanism understanding of the device performance change in the Zn(S,O)/Cu(In,Ga)Se2 solar cell with thermal annealing
No full textOne Place After Another : Site-Specific Art and Locational Identity
No full textKwon traces the development of site-specific art from the 1960s to the 1990s, examining site-specificity as a locus of the dynamic relationship between place and identity in late capitalism. The author distinguishes the more recent work from the earlier by highlighting how it points to the exhaustion of the rhetoric of political progressivism inherent in the practice. Characterising community as an inoperative spectre, Kwon calls for new models of belonging. Index. Circa 300 bibl. ref
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