ON-SURFACE MOLECULAR REACTIONS

2021 ◽  
pp. 2140006
Author(s):  
LIANGLIANG CAI ◽  
WEI XU
Keyword(s):  
Organic Reactions ◽  
Atomic Scale ◽  
Bottom Up ◽  
Molecular Reactions ◽  
Controllable Fabrication ◽  
External Stimuli ◽  
Ullmann Coupling ◽  
Glaser Coupling

During the last decades, the bottom–up strategy of on-surface molecular reactions has been extensively investigated in order to fulfill controllable fabrication of covalent interlinking nanostructures/nanomaterials at atomic scale. A variety of organic reactions have been introduced to substrates, such as Ullmann coupling, Glaser coupling, cyclodehydrogenation and so on. In this paper, these on-surface molecular reactions will be reviewed from three aspects: the precursor, surface and external stimuli. Finally, a summary of past achievements and an outlook of future scientific challenges will be discussed.

scholarly journals Bottom-Up Self-Assembly Based on DNA Nanotechnology

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2047
Author(s):  
Xuehui Yan ◽  
Shujing Huang ◽  
Yong Wang ◽  
Yuanyuan Tang ◽  
Ye Tian
Keyword(s):  
Self Assembly ◽  
Materials Science ◽  
Three Dimensional ◽  
Dna Nanotechnology ◽  
Atomic Scale ◽  
Biological Functions ◽  
Dna Molecules ◽  
Significant Progress ◽  
Bottom Up ◽  
Huge Challenge

Manipulating materials at the atomic scale is one of the goals of the development of chemistry and materials science, as it provides the possibility to customize material properties; however, it still remains a huge challenge. Using DNA self-assembly, materials can be controlled at the nano scale to achieve atomic- or nano-scaled fabrication. The programmability and addressability of DNA molecules can be applied to realize the self-assembly of materials from the bottom-up, which is called DNA nanotechnology. DNA nanotechnology does not focus on the biological functions of DNA molecules, but combines them into motifs, and then assembles these motifs to form ordered two-dimensional (2D) or three-dimensional (3D) lattices. These lattices can serve as general templates to regulate the assembly of guest materials. In this review, we introduce three typical DNA self-assembly strategies in this field and highlight the significant progress of each. We also review the application of DNA self-assembly and propose perspectives in this field.

Construction of a silicon-based solid state quantum computer

2001 ◽  
Vol 1 (Special) ◽  
pp. 82-95
Author(s):  
A.S. Dzurak ◽  
M.Y. Simmons ◽  
A.R. Hamilton ◽  
R.G. Clark ◽  
R. Brenner ◽  
...  
Keyword(s):  
Large Scale ◽  
Quantum Computer ◽  
Atomic Scale ◽  
Single Electron Transistor ◽  
Epitaxial Silicon ◽  
Top Down ◽  
Bottom Up ◽  
Near Term ◽  
Silicon Based ◽  
Coincidence Measurements

We discuss progress towards the fabrication and demonstration of a prototype silicon-based quantum computer. The devices are based on a precise array of 31P dopants embedded in 28Si. Fabrication is being pursued via two complementary pathways – a ‘top-down’ approach for near-term production of few-qubit demonstration devices and a ‘bottom-up’ approach for large-scale qubit arrays. The ‘top-down’ approach employs ion implantation through a multi-layer resist structure which serves to accurately register the donors to metal control gates and single-electron transistor (SET) read-out devices. In contrast the ‘bottom-up’ approach uses STM lithography and epitaxial silicon overgrowth to construct devices at an atomic scale. Techniques for qubit read-out, which utilise coincidence measurements on novel twin-SET devices, are also presented.

Atomic-scale insight into the formation, mobility and reaction of Ullmann coupling intermediates

2014 ◽  
Vol 50 (8) ◽  
pp. 1006-1008 ◽  
Author(s):  
Emily A. Lewis ◽  
Colin J. Murphy ◽  
Melissa L. Liriano ◽  
E. Charles H. Sykes
Keyword(s):  
Atomic Scale ◽  
Insight Into ◽  
Ullmann Coupling

scholarly journals Spectroscopic Evidence of New Low-Dimensional Planar Carbon Allotropes Based on Biphenylene via On-Surface Ullmann Coupling

Chemistry ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 1057-1062
Author(s):  
Teng Zhang ◽  
Cesare Grazioli ◽  
Huixia Yang ◽  
Kaiyue Jiang ◽  
Iulia Emilia Brumboiu ◽  
...  
Keyword(s):  
Bottom Up ◽  
Carbon Allotrope ◽  
Spectroscopic Evidence ◽  
Carbon Allotropes ◽  
Carbon Networks ◽  
The Many ◽  
Low Dimensional ◽  
Planar Carbon ◽  
Ullmann Coupling

The bottom-up synthesis and preliminary characterizations of a new biphenylene-based 2D framework are presented. This new low-dimensional carbon allotrope potentially completes the many hypothesized carbon networks based on biphenylene.

The Origin of Consciousness

2010 ◽  
Vol 18 (3) ◽  
pp. 481-495
Author(s):  
Jonathan Cole
Keyword(s):  
Clinical Medicine ◽  
Neural Correlates ◽  
Higher Order ◽  
Brain Anatomy ◽  
Special Issue ◽  
Top Down ◽  
Bottom Up ◽  
Neural Correlates Of Consciousness ◽  
Definition Of ◽  
External Stimuli

This paper introduces the background to the debate addressed by the papers of this Special Issue of Pragmatics & Cognition. Starting with a definition of consciousness it traces some ways in which the term is applied; from clinical medicine, where it relates somewhat crudely to responsiveness to external stimuli, to more cognitive and philosophical aspects such as higher order consciousness and its content. It then discusses the relation of consciousness to brain anatomy, the neural correlates of consciousness, and its possible evolution. In the meeting which forms the basis for Frith’s core paper, Christof Koch also made important contributions, here précised. A discussion of the origins of consciousness in relation to the top-down and bottom-up models brought to the fore follows suit.

scholarly journals Building Ferroelectric from the Bottom Up: The Machine Learning Analysis of the Atomic-Scale Ferroelectric Distortions

2019 ◽  
Author(s):  
Maxim Ziatdinov ◽  
Christopher Nelson ◽  
Rama Vasudevan ◽  
Deyang Chen ◽  
Sergei Kalinin
Keyword(s):  
Building Blocks ◽  
Atomic Displacement ◽  
Atomic Scale ◽  
Atomic Column ◽  
Bottom Up ◽  
Scanning Transmission ◽  
Classical Paper ◽  
Full Analysis ◽  
Ferroic Materials ◽  
Atomic Coordinates

<div>Recent advances in scanning transmission electron microscopy (STEM) have enabled direct visualization of the atomic structure of ferroic materials, enabling the determination of atomic column positions with ~pm precision. This, in turn, enabled direct mapping of ferroelectric and ferroelastic order parameter fields via the top-down approach, where the atomic coordinates are directly mapped on the mesoscopic order parameters. Here, we explore the alternative bottom-up approach, where the atomic coordinates derived from the STEM image are used to explore the extant atomic displacement patterns in the material and build the collection of the building blocks for the distorted lattice. This approach is illustrated for the La-doped BiFeO<sub>3</sub> system.</div><div>The full analysis procedure is available as an interactive paper in a form of a Google Colab (Jupyter) notebook where a classical paper organization is augmented with code cells that appear hidden by default (when viewed in Google Colab). This should allow a reader to retrace the analysis and, more importantly, it enables the readers to use the same codes for their data. The same paper is also available in a standard pdf format (without code).<br></div>

scholarly journals Bottom‐up Fabrication and Atomic‐scale Characterization of Triply‐linked, Laterally π‐Extended Porphyrin Nanotapes

2021 ◽  
Author(s):  
Qiang Sun ◽  
Luis M. Mateo ◽  
Roberto Robles ◽  
Nicolas Lorente ◽  
Pascal Ruffieux ◽  
...  
Keyword(s):  
Atomic Scale ◽  
Bottom Up ◽  
Scale Characterization

scholarly journals Atomic-scale observations of electrical and mechanical manipulation of topological polar flux closure

2020 ◽  
Vol 117 (32) ◽  
pp. 18954-18961 ◽  
Author(s):  
Xiaomei Li ◽  
Congbing Tan ◽  
Chang Liu ◽  
Peng Gao ◽  
Yuanwei Sun ◽  
...  
Keyword(s):  
Electric Field ◽  
Domain Wall Motion ◽  
Atomic Scale ◽  
Nanoelectronic Devices ◽  
The Core ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
External Stimuli ◽  
Closure Structure

The ability to controllably manipulate complex topological polar configurations such as polar flux-closures via external stimuli may allow the construction of new electromechanical and nanoelectronic devices. Here, using atomically resolved in situ scanning transmission electron microscopy, we find that the polar flux-closures in PbTiO3/SrTiO3superlattice films are mobile and can be reversibly switched to ordinary single ferroelectriccoradomains under an applied electric field or stress. Specifically, the electric field initially drives movement of a flux-closure via domain wall motion and then breaks it to form intermediatea/cstriped domains, whereas mechanical stress first squeezes the core of a flux-closure toward the interface and then forma/cdomains with disappearance of the core. After removal of the external stimulus, the flux-closure structure spontaneously recovers. These observations can be precisely reproduced by phase field simulations, which also reveal the evolutions of the competing energies during phase transitions. Such reversible switching between flux-closures and ordinary ferroelectric states provides a foundation for potential electromechanical and nanoelectronic applications.

scholarly journals Building Ferroelectric from the Bottom Up: The Machine Learning Analysis of the Atomic-Scale Ferroelectric Distortions

2019 ◽  
Author(s):  
Maxim Ziatdinov ◽  
Christopher Nelson ◽  
Rama Vasudevan ◽  
Deyang Chen ◽  
Sergei Kalinin
Keyword(s):  
Building Blocks ◽  
Atomic Displacement ◽  
Atomic Scale ◽  
Atomic Column ◽  
Bottom Up ◽  
Scanning Transmission ◽  
Classical Paper ◽  
Full Analysis ◽  
Ferroic Materials ◽  
Atomic Coordinates

<div>Recent advances in scanning transmission electron microscopy (STEM) have enabled direct visualization of the atomic structure of ferroic materials, enabling the determination of atomic column positions with ~pm precision. This, in turn, enabled direct mapping of ferroelectric and ferroelastic order parameter fields via the top-down approach, where the atomic coordinates are directly mapped on the mesoscopic order parameters. Here, we explore the alternative bottom-up approach, where the atomic coordinates derived from the STEM image are used to explore the extant atomic displacement patterns in the material and build the collection of the building blocks for the distorted lattice. This approach is illustrated for the La-doped BiFeO<sub>3</sub> system.</div><div>The full analysis procedure is available as an interactive paper in a form of a Google Colab (Jupyter) notebook where a classical paper organization is augmented with code cells that appear hidden by default (when viewed in Google Colab). This should allow a reader to retrace the analysis and, more importantly, it enables the readers to use the same codes for their data. The same paper is also available in a standard pdf format (without code).<br></div>

scholarly journals Building ferroelectric from the bottom up: The machine learning analysis of the atomic-scale ferroelectric distortions

2019 ◽  
Vol 115 (5) ◽  
pp. 052902 ◽  
Author(s):  
M. Ziatdinov ◽  
C. Nelson ◽  
R. K. Vasudevan ◽  
D. Y. Chen ◽  
S. V. Kalinin
Keyword(s):  
Machine Learning ◽  
Atomic Scale ◽  
Bottom Up ◽  
Learning Analysis
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