Anisotropic transport properties of graphene-based conductor materials

AbstractWe analyzed nanographite-based materials in a combined study including experimental analysis via 4-point probe STM and simulation to provide a complete picture of microscopic and macroscopic properties of the material. The two- and three-dimensional transport regimes were determined and evaluated regarding the anisotropy of the conductivity. The experimental results yield the full macroscopic conductivity tensor. Microstructural simulations are used to map those macroscopic properties to the microscopic building blocks of the sample. By combining those two, we present a coherent and comprehensive description of the electrical material parameters across several length scales.

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Lath Martensite Microstructure Modeling: A High-Resolution Crystal Plasticity Simulation Study

Materials ◽

10.3390/ma14030691 ◽

2021 ◽

Vol 14 (3) ◽

pp. 691

Author(s):

Francisco-José Gallardo-Basile ◽

Yannick Naunheim ◽

Franz Roters ◽

Martin Diehl

Keyword(s):

High Resolution ◽

Mechanical Behavior ◽

Crystal Plasticity ◽

Lath Martensite ◽

Three Dimensional ◽

Building Blocks ◽

Quantitative Agreement ◽

Carbon Steels ◽

Plastic Behavior ◽

Austenitic Phase

Lath martensite is a complex hierarchical compound structure that forms during rapid cooling of carbon steels from the austenitic phase. At the smallest, i.e., ‘single crystal’ scale, individual, elongated domains, form the elemental microstructural building blocks: the name-giving laths. Several laths of nearly identical crystallographic orientation are grouped together to blocks, in which–depending on the exact material characteristics–clearly distinguishable subblocks might be observed. Several blocks with the same habit plane together form a packet of which typically three to four together finally make up the former parent austenitic grain. Here, a fully parametrized approach is presented which converts an austenitic polycrystal representation into martensitic microstructures incorporating all these details. Two-dimensional (2D) and three-dimensional (3D) Representative Volume Elements (RVEs) are generated based on prior austenite microstructure reconstructed from a 2D experimental martensitic microstructure. The RVEs are used for high-resolution crystal plasticity simulations with a fast spectral method-based solver and a phenomenological constitutive description. The comparison of the results obtained from the 2D experimental microstructure and the 2D RVEs reveals a high quantitative agreement. The stress and strain distributions and their characteristics change significantly if 3D microstructures are used. Further simulations are conducted to systematically investigate the influence of microstructural parameters, such as lath aspect ratio, lath volume, subblock thickness, orientation scatter, and prior austenitic grain shape on the global and local mechanical behavior. These microstructural features happen to change the local mechanical behavior, whereas the average stress–strain response is not significantly altered. Correlations between the microstructure and the plastic behavior are established.

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Conical SNA using fuzzy k-medoids based on user experience

International Journal of Electrical Engineering Education ◽

10.1177/0020720920988490 ◽

2021 ◽

pp. 002072092098849

Author(s):

Poonam Rani ◽

MPS Bhatia ◽

Devendra K Tayal

Keyword(s):

Social Networks ◽

Social Network ◽

User Experience ◽

Three Dimensional ◽

Experimental Results ◽

Dynamic Parameters ◽

Clustering Method ◽

Cone Model ◽

Intelligent Approach ◽

Conical Model

The paper presents an intelligent approach for the comparison of social networks through a cone model by using the fuzzy k-medoids clustering method. It makes use of a geometrical three-dimensional conical model, which astutely represents the user experience views. It uses both the static as well as the dynamic parameters of social networks. In this, we propose an algorithm that investigates which social network is more fruitful. For the experimental results, the proposed work is employed on the data collected from students from different universities through the Google forms, where students are required to rate their experience of using different social networks on different scales.

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ChemInform Abstract: Efficient Synthetic Strategy to Construct Three-Dimensional 4f-5d Networks Using Neutral Two-Dimensional Layers as Building Blocks.

ChemInform ◽

10.1002/chin.201036013 ◽

2010 ◽

Vol 41 (36) ◽

pp. no-no

Author(s):

Hu Zhou ◽

Ai-Hua Yuan ◽

Su-Yan Qian ◽

You Song ◽

Guo-Wang Diao

Keyword(s):

Three Dimensional ◽

Building Blocks ◽

Two Dimensional ◽

Synthetic Strategy

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Design and Optimization of a Shape Memory Alloy-Based Self-Folding Sheet

Journal of Mechanical Design ◽

10.1115/1.4025382 ◽

2013 ◽

Vol 135 (11) ◽

Cited By ~ 39

Author(s):

Edwin Peraza-Hernandez ◽

Darren Hartl ◽

Edgar Galvan ◽

Richard Malak

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Three Dimensional ◽

Building Blocks ◽

Passive Layer ◽

Von Mises Stress ◽

Maximum Temperature ◽

Radius Of Curvature ◽

Folding Angle ◽

The Impact

Origami engineering—the practice of creating useful three-dimensional structures through folding and fold-like operations on two-dimensional building-blocks—has the potential to impact several areas of design and manufacturing. In this article, we study a new concept for a self-folding system. It consists of an active, self-morphing laminate that includes two meshes of thermally-actuated shape memory alloy (SMA) wire separated by a compliant passive layer. The goal of this article is to analyze the folding behavior and examine key engineering tradeoffs associated with the proposed system. We consider the impact of several design variables including mesh wire thickness, mesh wire spacing, thickness of the insulating elastomer layer, and heating power. Response parameters of interest include effective folding angle, maximum von Mises stress in the SMA, maximum temperature in the SMA, maximum temperature in the elastomer, and radius of curvature at the fold line. We identify an optimized physical realization for maximizing folding capability under mechanical and thermal failure constraints. Furthermore, we conclude that the proposed self-folding system is capable of achieving folds of significant magnitude (as measured by the effective folding angle) as required to create useful 3D structures.

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A new three-dimensional anionic cadmium(II) dicyanamide network

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229614022360 ◽

2014 ◽

Vol 70 (11) ◽

pp. 1054-1056 ◽

Cited By ~ 9

Author(s):

Qiang Li ◽

Hui-Ting Wang

Keyword(s):

Crystal Structure ◽

Aqueous Solution ◽

Unit Cell Volume ◽

Three Dimensional ◽

Building Blocks ◽

The Other ◽

Dimensional Structure ◽

Cadmium Nitrate ◽

Nitrate Tetrahydrate ◽

Anionic Framework

A new cadmium dicyanamide complex, poly[tetramethylphosphonium [μ-chlorido-di-μ-dicyanamido-κ4N1:N5-cadmium(II)]], [(CH3)4P][Cd(NCNCN)2Cl], was synthesized by the reaction of tetramethylphosphonium chloride, cadmium nitrate tetrahydrate and sodium dicyanamide in aqueous solution. In the crystal structure, each CdIIatom is octahedrally coordinated by four terminal N atoms from four anionic dicyanamide (dca) ligands and by two chloride ligands. The dicyanamide ligands play two different roles in the building up of the structure; one role results in the formation of [Cd(dca)Cl]2building blocks, while the other links the building blocks into a three-dimensional structure. The anionic framework exhibits a solvent-accessible void of 673.8 Å3, amounting to 47.44% of the total unit-cell volume. The cavities in the network are occupied by pairs of tetramethylphosphonium cations.

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Assembly of multicomponent structures from hundreds of micron-scale building blocks using optical tweezers

Microsystems & Nanoengineering ◽

10.1038/s41378-021-00272-z ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Jeffrey E. Melzer ◽

Euan McLeod

Keyword(s):

Optical Tweezers ◽

Three Dimensional ◽

Building Blocks ◽

Optical Tweezer ◽

Device Fabrication ◽

Positional Accuracy ◽

Component Structure ◽

Material Development ◽

Critical Process Parameters ◽

Optical Positioning

AbstractThe fabrication of three-dimensional (3D) microscale structures is critical for many applications, including strong and lightweight material development, medical device fabrication, microrobotics, and photonic applications. While 3D microfabrication has seen progress over the past decades, complex multicomponent integration with small or hierarchical feature sizes is still a challenge. In this study, an optical positioning and linking (OPAL) platform based on optical tweezers is used to precisely fabricate 3D microstructures from two types of micron-scale building blocks linked by biochemical interactions. A computer-controlled interface with rapid on-the-fly automated recalibration routines maintains accuracy even after placing many building blocks. OPAL achieves a 60-nm positional accuracy by optimizing the molecular functionalization and laser power. A two-component structure consisting of 448 1-µm building blocks is assembled, representing the largest number of building blocks used to date in 3D optical tweezer microassembly. Although optical tweezers have previously been used for microfabrication, those results were generally restricted to single-material structures composed of a relatively small number of larger-sized building blocks, with little discussion of critical process parameters. It is anticipated that OPAL will enable the assembly, augmentation, and repair of microstructures composed of specialty micro/nanomaterial building blocks to be used in new photonic, microfluidic, and biomedical devices.

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