From Materials Today
Materials in Focus
 |
A single molecule constitutes the ultimate nanometer-scale object through which electronic transport can take place. A research team has now showed how magnetism and quantum many-body phenomena can be tuned by precise mechanical manipulation of single molecules. They investigated the magnetic states of individual spin = 1 molecules placed between two electrodes in a metal break junction. By stretching the electrodes, they explored the resulting symmetry-breaking effects of this mechanical action on the conduction properties through the molecule, focusing on magnetic anisotropy. [Science]
3-D imaging of pore structures in low-κ dielectrics
(Eurekalert/Cornell University)
Pore structures in an insulation material at a sub-nanometer scale have been imaged for the first time. Porous, low-dielectric constant materials are being used to replace silicon dioxide as the insulator between nano-scaled copper wires in current and future microelectronic devices and chips in order to speed up the electrical signals sent along these copper wires inside a computer chip, and at the same time reduce power consumption. Researchers were able to devise a method to obtain 3-D images of the pores using electron tomography, leveraging imaging advances used for CT scans and MRIs in the medical field, yielding 3-D images with near atomic resolution. [Appl. Phys. Lett.]
(Eurekalert/Cornell University)
Pore structures in an insulation material at a sub-nanometer scale have been imaged for the first time. Porous, low-dielectric constant materials are being used to replace silicon dioxide as the insulator between nano-scaled copper wires in current and future microelectronic devices and chips in order to speed up the electrical signals sent along these copper wires inside a computer chip, and at the same time reduce power consumption. Researchers were able to devise a method to obtain 3-D images of the pores using electron tomography, leveraging imaging advances used for CT scans and MRIs in the medical field, yielding 3-D images with near atomic resolution. [Appl. Phys. Lett.]
Reactions in a molecular single crystal
(Chemistry World)
Crystals that can alter their composition without changing the structure of their solid lattice have been developed. The crystals are made from an iridium complex bonded to dinitrogen (N2), but other gases such as hydrogen or ammonia can diffuse through the lattice and undergo reactions. Since larger molecules such as propene cannot enter the crystalline lattice, the process is highly selective. The secret of these crystals lies in the composition: iridium ions surrounded by large pincer-like ligands. The complicated ligands give the iridium high reactivity (allowing it to complex with nitrogen gas) but also leave voids in the crystalline lattice. The voids act as tunnels, which small gases can use to traverse the structure. [Nature]
(Chemistry World)
Crystals that can alter their composition without changing the structure of their solid lattice have been developed. The crystals are made from an iridium complex bonded to dinitrogen (N2), but other gases such as hydrogen or ammonia can diffuse through the lattice and undergo reactions. Since larger molecules such as propene cannot enter the crystalline lattice, the process is highly selective. The secret of these crystals lies in the composition: iridium ions surrounded by large pincer-like ligands. The complicated ligands give the iridium high reactivity (allowing it to complex with nitrogen gas) but also leave voids in the crystalline lattice. The voids act as tunnels, which small gases can use to traverse the structure. [Nature]
Energy Focus
NMR Observations of Li "Moss" Formation in Li Batteries
(Materials for Energy Blog)
Lithium ion batteries (LIBs) are widely used because of their large energy storage densities. There is an even larger demand for more energy from LIBs that can be met by using Li metal-containing negative electrodes instead of graphite and other anodes currently used. One of the problems with Li electrodes is that after several charge/discharge cycles in non-aqueous electrolytes, dendritic Li metal, sometimes called Li "moss," forms on the Li-metal anode. Some of these dendrites can fall off into the electrolyte. These floating Li fibers, along with those on the electrode itself, cause various problems, including short circuits and subsequent overheating. A new study now reports the use of in situ nuclear magnetic resonance (NMR) for investigating the Li dendrite formation during electrochemical cycling to better understand and control it. [Nature Materials]
(Materials for Energy Blog)
Lithium ion batteries (LIBs) are widely used because of their large energy storage densities. There is an even larger demand for more energy from LIBs that can be met by using Li metal-containing negative electrodes instead of graphite and other anodes currently used. One of the problems with Li electrodes is that after several charge/discharge cycles in non-aqueous electrolytes, dendritic Li metal, sometimes called Li "moss," forms on the Li-metal anode. Some of these dendrites can fall off into the electrolyte. These floating Li fibers, along with those on the electrode itself, cause various problems, including short circuits and subsequent overheating. A new study now reports the use of in situ nuclear magnetic resonance (NMR) for investigating the Li dendrite formation during electrochemical cycling to better understand and control it. [Nature Materials]
Nano Focus
Performance of graphene monolayer nanocomposite
(PhysOrg.com)
A new study suggests that graphene has the potential to replace carbon fibers in high performance composites such as those used to build aircraft. Researchers placed a single graphene sheet between two layers of polymer and used Raman spectroscopy to measure the response of the carbon bonds to stretching of the graphene. The results suggested that theories developed for large materials still hold even when a material is just one atom thick. The vast body of research into traditional carbon fiber composites can consequently be tapped to design the next generation of graphene-based materials. [Advanced Materials]
(PhysOrg.com)
A new study suggests that graphene has the potential to replace carbon fibers in high performance composites such as those used to build aircraft. Researchers placed a single graphene sheet between two layers of polymer and used Raman spectroscopy to measure the response of the carbon bonds to stretching of the graphene. The results suggested that theories developed for large materials still hold even when a material is just one atom thick. The vast body of research into traditional carbon fiber composites can consequently be tapped to design the next generation of graphene-based materials. [Advanced Materials]
 |
Efficient guiding and confinement of single-mode light in GaAs/AlGaAs nanowaveguides require high-aspect-ratio geometries. To prevent the structures from collapsing, almost perfectly vertical sidewalls are mandatory. In a recently published study, researchers used a top-down approach to fabricate such a nanowaveguide. High-resolution electron beam lithography patterning was carried out using an e-beam writer to define the structures. Then, a set of inductively coupled plasma (ICP) etching processes removed unwanted material from around the design. Near-ideal vertical sidewalls were obtained allowing for the production of extremely high aspect ratio (>32 for 80 nm wide) nanowaveguides. [Nanotechnology]
Fluctuations in current in a quantum dot junction
(Physics)
Traffic congestion can make life difficult for electrons in nanodevices. Now, in a new study, a team of scientists point to the subtle but significant deviations from steady-state behavior that appear if one looks at the time dependence of electrons traversing a nanoscale junction. They predict that on a femtosecond time scale, the current in a quantum dot junction is not in a steady state, as often assumed, but rather oscillates. The amplitude of this oscillation depends on how fast the bias voltage across the dot is switched on, suggesting the importance of initial conditions in determining how a single-electron device will perform. [Phys. Rev. Lett.]
(Physics)
Traffic congestion can make life difficult for electrons in nanodevices. Now, in a new study, a team of scientists point to the subtle but significant deviations from steady-state behavior that appear if one looks at the time dependence of electrons traversing a nanoscale junction. They predict that on a femtosecond time scale, the current in a quantum dot junction is not in a steady state, as often assumed, but rather oscillates. The amplitude of this oscillation depends on how fast the bias voltage across the dot is switched on, suggesting the importance of initial conditions in determining how a single-electron device will perform. [Phys. Rev. Lett.]
Bio Focus
Molecularly imprinted polymer nanoparticles: A plastic antibody
(Eurekalert)
Scientists are reporting the first evidence that a polymer antibody — an artificial version of the proteins produced by the body's immune system to recognize and fight infections and foreign substances — works in the bloodstream of a living animal. The discovery is an advance toward medical use of simple polymer nanoparticles custom tailored to fight an array of troublesome "antigens." The researchers developed a method for making polymer nanoparticles that mimic natural antibodies in their ability to latch onto an antigen, melittin, the main toxin in bee venom. They make the antibody using molecular imprinting.They established that these polymer melittin antibodies worked like natural antibodies in mice. The animals that immediately received an injection of the melittin-targeting polymer antibody showed a significantly higher survival rate than those that did not receive the nanoparticles. [J. Am. Chem. Soc.]
(Eurekalert)
Scientists are reporting the first evidence that a polymer antibody — an artificial version of the proteins produced by the body's immune system to recognize and fight infections and foreign substances — works in the bloodstream of a living animal. The discovery is an advance toward medical use of simple polymer nanoparticles custom tailored to fight an array of troublesome "antigens." The researchers developed a method for making polymer nanoparticles that mimic natural antibodies in their ability to latch onto an antigen, melittin, the main toxin in bee venom. They make the antibody using molecular imprinting.They established that these polymer melittin antibodies worked like natural antibodies in mice. The animals that immediately received an injection of the melittin-targeting polymer antibody showed a significantly higher survival rate than those that did not receive the nanoparticles. [J. Am. Chem. Soc.]
Blowing bubbles to study eye disease
(Highlights in Chemical Science)
A method to probe the mechanical properties of eye tissue has been developed. One of the most common methods involves a doctor feeling the eye for regions of different stiffness to normal, but the success is highly dependent on the investigator's skill and the information gained is qualitative. Now researchers have shown that a technique used to study synthetic gels, known as cavitation rheology, can be applied to eye tissue. Cavitation rheology is performed by connecting a needle to a syringe and inserting it into soft tissue, in this case the vitreous - a gel-like tissue in the eye. The pressure inside the system is gradually increased until, at a particular pressure, a bubble forms at the end of the needle inside the tissue. The pressure at which the bubble appears is related to the mechanical properties of the material. [Soft Matter]
(Highlights in Chemical Science)
A method to probe the mechanical properties of eye tissue has been developed. One of the most common methods involves a doctor feeling the eye for regions of different stiffness to normal, but the success is highly dependent on the investigator's skill and the information gained is qualitative. Now researchers have shown that a technique used to study synthetic gels, known as cavitation rheology, can be applied to eye tissue. Cavitation rheology is performed by connecting a needle to a syringe and inserting it into soft tissue, in this case the vitreous - a gel-like tissue in the eye. The pressure inside the system is gradually increased until, at a particular pressure, a bubble forms at the end of the needle inside the tissue. The pressure at which the bubble appears is related to the mechanical properties of the material. [Soft Matter]
New technique turns proteins into glass
(Science Daily)
A method to dry and preserve proteins in a glassified form that seems to retain the molecules' properties has been developed. This glassification process is described as "molecular water surgery" because it removes virtually all the water from around a dissolved protein by pulling the water into a second solvent. The researchers were able to carefully control water removal during glassification by releasing single tiny droplets of water-dissolved protein into the organic solvent decanol with a micropipette. Preliminary evaluations showed that four test proteins undergoing such procedures retained all or most of their original activity when water was restored. The glassy microbeads measured only about 26 millionths of a meter in diameter. [Biophysical Journal]
(Science Daily)
A method to dry and preserve proteins in a glassified form that seems to retain the molecules' properties has been developed. This glassification process is described as "molecular water surgery" because it removes virtually all the water from around a dissolved protein by pulling the water into a second solvent. The researchers were able to carefully control water removal during glassification by releasing single tiny droplets of water-dissolved protein into the organic solvent decanol with a micropipette. Preliminary evaluations showed that four test proteins undergoing such procedures retained all or most of their original activity when water was restored. The glassy microbeads measured only about 26 millionths of a meter in diameter. [Biophysical Journal]
Image in Focus
Click to enlarge
Watermelons on Pandora
Colorized scanning electron microscope image of superparamagnetic poly methyl methacrylate (PMMA) microspheres with Fe2O3 nanocrystals self-assembled on the surface and inside. Credit: Yongxing Hu, University of California, Riverside
(One of three Second Place winners of the Science as Art competition at the 2010 MRS Spring Meeting)
Colorized scanning electron microscope image of superparamagnetic poly methyl methacrylate (PMMA) microspheres with Fe2O3 nanocrystals self-assembled on the surface and inside. Credit: Yongxing Hu, University of California, Riverside
(One of three Second Place winners of the Science as Art competition at the 2010 MRS Spring Meeting)
[Submit your images to the Editor for possible inclusion in this feature]
Industry Focus
Fibertect® CS Approved by EPA
Fibertect® Cotton-Soaking (CS), a three-layer flexible, inert, nonwoven, non-particulate decontamination system that has been proven to be successful in absorbing and adsorbing chemical warfare agents, may now prove useful in recovery efforts in the British Petroleum (BP) Deepwater Horizon disaster and other oil spills of similar size and severity. Fibertect® CS was developed by Texas Tech University and is manufactured by Hobbs Bonded Fibers for First Line Technology. The three layers of material consist of a top and bottom fabric with a center layer of fibrous activated carbon that is needle punched into a composite fabric. The top and bottom layers provide structural coherence, improving mechanical strength and abrasion resistance while the center layer holds volatile compounds, like oil.
Fibertect® Cotton-Soaking (CS), a three-layer flexible, inert, nonwoven, non-particulate decontamination system that has been proven to be successful in absorbing and adsorbing chemical warfare agents, may now prove useful in recovery efforts in the British Petroleum (BP) Deepwater Horizon disaster and other oil spills of similar size and severity. Fibertect® CS was developed by Texas Tech University and is manufactured by Hobbs Bonded Fibers for First Line Technology. The three layers of material consist of a top and bottom fabric with a center layer of fibrous activated carbon that is needle punched into a composite fabric. The top and bottom layers provide structural coherence, improving mechanical strength and abrasion resistance while the center layer holds volatile compounds, like oil.
2 comments:
This is really interesting take on the concept. I never thought of it that way. I came across this site recently which I think it will be a great use of new ideas and informations.
Hi,
Nice creativity i like it,
In the life sciences laboratory environment, there are few pieces of equipment which see more use than a multichannel pipette and along with it, pipette tips.
Post a Comment