Showing posts with label nanotechnology. Show all posts
Showing posts with label nanotechnology. Show all posts
Software review:VNL and ATK(nanotechnology)
QuantumWise provides two different interfaces for performing electronic transport calculations:
· Virtual NanoLab (VNL)
· Atomistix ToolKit (ATK)
Virtual NanoLab (VNL) is a graphical user interface (GUI), and Atomistix ToolKit (ATK) is the script-based interface. Which of the interfaces to use, is sometimes a matter of taste, and sometimes determined by the task at hand. VNL is the most appealing option, because of its intuitive ease of use. Some prefer ATK because it gives more control and flexibility through scripting.
A modeling study generally consists of three parts:
· Setting up the calculation
· Running the calculation
· Analyzing the output of the calculation.
User can get control of these steps using ATK, often in combination with VNL.
Virtual Nano Lab:
VNL allows to:
· design nanosystems
· Set-up and execute numerical calculations
· Visualize the results
· Graphical user interface-easy to use
· User friendly approach to atomic scale modeling
· Contains a set of interactive instruments
Its main advantage is to provide 3 D visualization tool Nanoscope to view and analyze the atomic geometries and computed results.
Applications:
- Calculation of transport properties of two-probe systems under an applied bias voltage
- Calculation of energy spectra, wave functions, electron densities, atomic forces, effective potentials etc.
- Calculation of spin polarized physical properties
- Geometry optimization
Calculations:
It calculates:
- Electronic Structure
- I–V Curves
- Schottky Barriers
- Conductance
- Contact Resistance
- Tunnel Magneto-Resistance
- Effect of doping/defects
- Charge Stability Diagrams
Samples:
The sample can:
· model isolated molecules as well as periodic systems such as
– Molecules
– Nanotubes
– Crystalline systems
· Can model complex nanostructures that combine molecules with periodic
systems and macroscopic elements
– Two probe systems (electrode-nanostructure electrode systems).
Unlike ATK: it calculates several physical quantities without the need to specify them
explicitly:
• ElectronDifferenceDensity
• ElectrostaticDifferencePotential
• Total Energy
Atomistix Tool Kit:
It is a:
· Numerical engine that carries out the actual simulations
· Ab initio electronic-structure and transport calculations
· Python based Nanolanguage scripting environment-more control and flexibility
· First principles electronic structure program
Unlike VNL: it gives more control and flexibility through scripting.
Key Features:
· Calculation of electronic properties
· Access to DFT algorithms
Quantum Mechanical models in ATK:
· Density Functional Theory (DFT)
· Non-equilibrium Green’s Function/Equilibrium
· Green’s Function
· Pseudopotentials
· Numerical basis sets
· Semi-empirical models
References:
Labels:
nanotechnology
Conference on Multifunctional, Hybrid and Nanomaterials
What is hybrid conference?
Energy, the environment and human health have emerged as strategic priorities not only in research but in all aspects of our lives. Hybrid materials have already demonstrated good promise in addressing and offering solutions in each of these priority areas.
The main objective of this interdisciplinary conference is to bring together, at a truly international level, people with shared interests in hybrid materials, including:
Clément Sanchez, Collège de France, Paris, France
Ulrich Schubert, Technische Universität Wien, Austria
Dongyuan Zhao, Fudan University, Shanghai, China
Energy, the environment and human health have emerged as strategic priorities not only in research but in all aspects of our lives. Hybrid materials have already demonstrated good promise in addressing and offering solutions in each of these priority areas.
The main objective of this interdisciplinary conference is to bring together, at a truly international level, people with shared interests in hybrid materials, including:
- Polymer chemists, physicists and engineers
- Biomaterials chemists, physicists and engineers
- Organic chemists
- Inorganic chemists
- Solid state chemists
- Sol-gel chemists
- Composites scientists
- Colloid chemists and physicists
- Zeolite, meso- and microporous materials scientists
- Broad nano- and materials scientists
Conference Chairs
Kris Matyjaszewski, Carnegie Mellon University, Pittsburgh, PA, USAClément Sanchez, Collège de France, Paris, France
Ulrich Schubert, Technische Universität Wien, Austria
Dongyuan Zhao, Fudan University, Shanghai, China
Local Chair
Marc Drillon, IPCMS, Strasbourg, France
Labels:
nanotechnology
Gold Nanoparticles Could Transform Trees Into Street Lights
Street lights are an important part of our urban infrastructure — they light our way home and make the roads safe at night. But what if we could create natural street lights that don’t need electricity to power them? A group of scientists in Taiwan recently discovered that placing gold nanoparticles within the leaves of trees, causes them to give off a luminous reddish glow. The idea of using trees to replace street lights is an ingenious one – not only would it save on electricity costs and cut CO2 emissions, but it could also greatly reduce light pollution in major cities.
The discovery came about accidentally after the scientists were looking for a way to create high-efficiency lighting similar to LED technology, but without using toxic chemicals such as phosphor powder. Speaking about the development, Professor Shih-Hui Chang said, “Light emitting diode (LED) has replaced traditional light source in many display panels and street lights on the road. A lot of light emitting diode, especially white light emitting diode, uses phosphor powder to stimulate light of different wavelengths. However, phosphor powder is highly toxic and its price is expensive. As a result, Dr. Yen-Hsun Wu had the idea to discover a method that is less toxic to replace phosphor powder. This is a major motivation for him to engage in the research at the first place.”
By implanting the gold nanoparticles into the leaves of the Bacopa caroliniana plants, the scientists were able to induce the chlorophyll in the leaves to produce a red emission. Under a high wavelength of ultraviolet light, the gold nanoparticles were able to produce a blue-violet fluorescence to trigger a red emission in the surrounding chlorophyll.
“In the future, bio-LED could be used to make roadside trees luminescent at night. This will save energy and absorb CO2 as the bio-LED luminescence will cause the chloroplast to conduct photosynthesis,” Dr. Yen-Hsun Su said in an interview with Chemistry World. The Royal Society of Chemistry, the largest organization in Europe for advancing the chemical sciences, has applauded the discovery and published the paper by lead scientist Dr. Yen-Hsun Wu in the journal Nanoscale
Labels:
nanotechnology
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