Within graphene research, transmission electron microscopy (TEM) has proven to be an extremely useful and versatile characterization tool. However, the electron beam can interact with the sample leading to its modification during the process. This may be an undesirable effect and measures to avoid this do exist. In other cases, however, electron beam-sample interactions can be useful for nanoengineering or nanomanufacturing. It is therefore crucially important to understand how a material responds to the electron beam and the environment inside a TEM. In new work, researchers have now demonstrated that damage-free sculpting of graphene with condensed electron beams is feasible.
Power dissipation is the limiting factor to the continued scaling of size and speed of conventional silicon technology used for fabrication of integrated circuits and computer chips. For each switch of a transistor, an amount of energy needs to be dissipated that is proportional to the number of electrons and temperature. This condition is of a fundamental nature, resulting from the laws of thermodynamics.However, the assumption underlying this fundamental limit is that the electrons or spins act as an ensemble of independent particles. If instead, the electrons are in a collective state, then the minimum dissipation limit for one switching cycle can be greatly reduced. This fact provides a strong motivation to exploit collective states as alternative variables for information processing.
Protection against nerve agents - such as tabun, sarin, soman, VX, and others - is a major terrorism concern of security experts. Current methods to detect nerve agents include surface acoustic wave sensors; conducting polymer arrays; vector machines; and the most simple: color change paper sensors. Most of these systems have have certain limitations including low sensitivity and slow response times. Nanoporous material can remove highly toxic nerve agent vapors by physical adsorption. Unfortunately, the broad range of toxic agents, environmental conditions and types of carbonaceous material simply does not allow laboratory testing of every possible combination. New research is now shedding new light on the selection of an optimal nanomaterial for capturing highly volatile nerve agents.
Recent developments in nanotechnology have enabled significant improvement in the field of anti-counterfeiting measures. One company for instance is working on fluorescent nanostructures to improve banknote security; another one has developed DNA tags for deposition on nanoelectronics wafers and computer chips to ensure the integrity and security of processed wafers. DNA-based protection technologies are especially suitable for anti-counterfeiting measures.The DNA molecules are added a products raw material during the production process. Only 1 ppm (one part per million) is required to uniquely mark the material The DNA molecular structure can then be read as a mathematical code based on the four DNA molecules. So a DNA code, in contrast to the binary code used in IT security, is a combination of the letters A, C, G and T. A 10-digit code could look like this: C-G-A-C-T-T-G-A-C-A.
The refractive index is the property of a material that changes the speed of light and describes how light propagates through the material. The refractive index is an important property of solar cells - the higher it is, the more incident light gets reflected and is not converted to a photocurrent. Solar cell manufacturers have developed various kinds of antireflection coatings to reduce the unwanted reflective losses. The purpose of these optical thin-films is to minimize the differences in the refractive indices between the ambient medium and the solar cells. For both solar cells and LEDs, coating with nanoparticles can enhance the performance without harming the electrical properties of the devices, as can occur with etching or lithographic processing. In new work, researchers have now have not only demonstrated this advantageous feature but also provided a strategy for optimizing the types and sizes of nanoparticles for use in both solar cells and LEDs.
When a nanomaterial enters a biological environment, it comes into contact with a complex mixture of proteins. Some of these proteins can adhere to the surface of the nanomaterial, forming a protein 'corona' that influences its subsequent biological interactions. While a number of studies have characterized the protein corona formed around nanomaterials with diameters greater than 10nm, until now, lack of a suitable separation technique has prevented researchers from studying the protein corona formed around 'ultrasmall' nanomaterials. A team of European researchers used electrophoresis to separate ultrasmall nanomaterials from free protein. Applying this technique, they discovered that ultrasmall nanomaterials interact with proteins in a way that is fundamentally different from larger nanomaterials with analogous composition.
The ideal drug carrier may be something out of science fiction. In principle, it is injected into the body and transports itself to the correct target, such as a tumor, and delivers the required dose at this target. This idealized concept was first proposed by Paul Ehrlich at the beginning of the 20th century and was nicknamed the 'magic bullet' concept. With the advent of nanotechnology and nanomedicine this dream is rapidly becoming a reality. Researchers have already demonstrated that unctionalized carbon nanotubes (CNTs) might be able to target specific cells, become ingested, and then release their contents in response to a chemical trigger. A group of researchers has now essentially achieved this goal. They have encapsulated drugs inside carbon nanotubes for drug delivery and shown that these drugs can be released 'on command' by inductive heating with an external alternating current or pulsed magnetic field.
In order to fabricate stimuli-responsive materials, researchers have shown a lot of interest in asymmetric materials such as modulated gels which consist of a controlled layer that is responsive to an environmental stimuli and a nonresponsive substrate layer. And while much effort has gone into creating free-standing films through layer-by-layer (LbL) assembly, relatively little attention has been paid to the asymmetric properties or functionalization of the two surfaces of such free-standing layer-by-layer films. In new work, researchers have now reported the fabrication of asymmetric free-standing layer-by-layer film with asymmetric wettability - one surface is superhydrophobic and the other one is hydrophilic. The superhydrophobic side is water-repellent while the hydrophilic side can absorb/desorb water easily.