Multi-scale Analysis of the Crystallization of Amorphous Germanium Telluride

2014 ◽  
Vol 1697 ◽  
Author(s):  
Jie Liu ◽  
Xu Xu ◽  
Lucien Brush ◽  
M. P. Anantram

ABSTRACTThe crystallization properties of the phase change material (PCM) germanium telluride (GeTe) are investigated. It is shown that the critical nucleus radius of a crystalline cluster is smaller than 1.4nm when the annealing temperature is lower than 600K, indicating an extremely promising scaling scenario. It is revealed that the elastic energy, which is largely ignored in existing PCM crystallization studies, plays an important role in determining various crystallization properties and the ultimate scaling limit of the PCM. By omitting the influence of elastic energy, the critical formation energy (critical nuclei radius) will be underestimated by 41.7% (22.4%), and the nucleation rate will be overestimated by 74.2% when the annealing temperature is 600 K. The methodology proposed here is capable of quantitatively calculating the nucleation rate and growth speed of amorphous PCM from first principle calculations, which is relevant to computational design and optimization of PCM.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Aditya Shekhar Nittala ◽  
Andreas Karrenbauer ◽  
Arshad Khan ◽  
Tobias Kraus ◽  
Jürgen Steimle

AbstractElectro-physiological sensing devices are becoming increasingly common in diverse applications. However, designing such sensors in compact form factors and for high-quality signal acquisition is a challenging task even for experts, is typically done using heuristics, and requires extensive training. Our work proposes a computational approach for designing multi-modal electro-physiological sensors. By employing an optimization-based approach alongside an integrated predictive model for multiple modalities, compact sensors can be created which offer an optimal trade-off between high signal quality and small device size. The task is assisted by a graphical tool that allows to easily specify design preferences and to visually analyze the generated designs in real-time, enabling designer-in-the-loop optimization. Experimental results show high quantitative agreement between the prediction of the optimizer and experimentally collected physiological data. They demonstrate that generated designs can achieve an optimal balance between the size of the sensor and its signal acquisition capability, outperforming expert generated solutions.


2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Shuo Zhang ◽  
Sanjairaj Vijayavenkataraman ◽  
Geng Liang Chong ◽  
Jerry Ying Hsi Fuh ◽  
Wen Feng Lu

Nerve guidance conduits (NGCs) are tubular tissue engineering scaffolds used for nerve regeneration. The poor mechanical properties and porosity have always compromised their performances for guiding and supporting axonal growth. Therefore, in order to improve the properties of NGCs, the computational design approach was adopted to investigate the effects of different NGC structural features on their various properties, and finally, design an ideal NGC with mechanical properties matching human nerves and high porosity and permeability. Three common NGC designs, namely hollow luminal, multichannel, and microgrooved, were chosen in this study. Simulations were conducted to study the mechanical properties and permeability. The results show that pore size is the most influential structural feature for NGC tensile modulus. Multichannel NGCs have higher mechanical strength but lower permeability compared to other designs. Square pores lead to higher permeability but lower mechanical strength than circular pores. The study finally selected an optimized hollow luminal NGC with a porosity of 71% and a tensile modulus of 8 MPa to achieve multiple design requirements. The use of computational design and optimization was shown to be promising in future NGC design and nerve tissue engineering research.


2007 ◽  
Author(s):  
Alejandro M. Aragón ◽  
Christopher J. Hansen ◽  
Willie Wu ◽  
Philippe H. Geubelle ◽  
Jennifer Lewis ◽  
...  

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Zilong Li ◽  
Songming Hou ◽  
Thomas C. Bishop

Abstract The Magic Snake (Rubik’s Snake) is a toy that was invented decades ago. It draws much less attention than Rubik’s Cube, which was invented by the same professor, Erno Rubik. The number of configurations of a Magic Snake, determined by the number of discrete rotations about the elementary wedges in a typical snake, is far less than the possible configurations of a typical cube. However, a cube has only a single three-dimensional (3D) structure while the number of sterically allowed 3D conformations of the snake is unknown. Here, we demonstrate how to represent a Magic Snake as a one-dimensional (1D) sequence that can be converted into a 3D structure. We then provide two strategies for designing Magic Snakes to have specified 3D structures. The first enables the folding of a Magic Snake onto any 3D space curve. The second introduces the idea of “embedding” to expand an existing Magic Snake into a longer, more complex, self-similar Magic Snake. Collectively, these ideas allow us to rapidly list and then compute all possible 3D conformations of a Magic Snake. They also form the basis for multidimensional, multi-scale representations of chain-like structures and other slender bodies including certain types of robots, polymers, proteins, and DNA.


Author(s):  
Paul F. Egan ◽  
Philip R. LeDuc ◽  
Jonathan Cagan ◽  
Christian Schunn

As technology advances, there is an increasing need to reliably output mechanical work at smaller scales. At the nanoscale, one of the most promising routes is utilizing biomolecular motors such as myosin proteins commonly found in cells. Myosins convert chemical energy into mechanical energy and are strong candidates for use as components of artificial nanodevices and multi-scale systems. Isoforms of the myosin superfamily of proteins are fine-tuned for specific cellular tasks such as intracellular transport, cell division, and muscle contraction. The modular structure that all myosins share makes it possible to genetically engineer them for fine-tuned performance in specific applications. In this study, a parametric analysis is conducted in order to explore the design space of Myosin II isoforms. The crossbridge model for myosin mechanics is used as a basis for a parametric study. The study sweeps commonly manipulated myosin performance variables and explores novel ways of tuning their performance. The analysis demonstrates the extent that myosin designs are alterable. Additionally, the study informs the biological community of gaps in experimentally tabulated myosin design parameters. The study lays the foundation for further progressing the design and optimization of individual myosins, a pivotal step in the eventual utilization of custom-built biomotors for a broad range of innovative nanotechnological devices.


2020 ◽  
Vol 39 (2) ◽  
pp. 399-409
Author(s):  
Hao Xu ◽  
Tianwen Fu ◽  
Peng Song ◽  
Mingjun Zhou ◽  
Chi‐Wing Fu ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document