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2003
Special Feature
Space Shuttle Columbia Disaster - Materials
Issues
December
Biotechnology: Materials research continues to court biotechnology
(EE Times)
Report on the recently held 2003 MRS Fall Meeting in Boston.
(12.22.03)
Physics Highlights 2003 : Top physics stories of the year
(PhysicsWeb)
Top physics stories of the year for 2003 selected by the Editors of PhysicsWeb that includes several materials related work.
(12.22.03)
Chemistry Highlights 2003 : Materials advances
(Chemical and Engineering News)
Materials advances in 2003 from a chemistry perspective
(12.22.03)
Silicon ICs : Scaling CMOS: Materials and devices
(Materials Today)(PDF)
Article overviewing the current status of CMOS scaling, including some details of current research.
(12.22.03)
Optical Fibers: Optical fibres cut their losses
(Nature)
Super-thin subwavelength-diameter silica optical fibers have been produced that are 10,000 times thinner than currently used optical fibers. These new fibers could significantly reduce leakage and have telecommunications as well as photonics applications.
(12.18.03)
Chemistry: Synthesis of a Möbius aromatic hydrocarbon
(Nature)
In 1964, it was predicted that it should be possible to synthesize an aromatic Möbius-like twisted annulene molecule. A Möbius band is 2-dimensional but has only one side. Now, stable Möbius-twisted annulenes have been produced, and the 40-year old prediction has come true.
(12.18.03)
Nanotechnology: What is there to fear from something so small?
(Nature)
Commentary on social aspects and current fears relating to nanotechnology.
(12.18.03)
Semiconductors: Indium nitride springs a surprise
(PhysicsWeb)
Researchers have shown clear evidence for a layer of accumulated electrons on the surface of indium nitride. These results indicate that metal-semiconductor contacts would have low resistance and no Schottky barrier.
(12.12.03)
Organic Electronics : Organic transistors speed up
(IEEE Spectrum)
Two research groups, in the US and the Netherlands, have tweaked the manufacturing process of single-crystal organic field-effect transistors (OFETs) to boost their switching speeds.
(12.12.03)
"Nanolens": Small spheres make a big signal
(Physical Review Focus)
A group has proposed using a series of three successively smaller metal nanospheres in a row, ranging in diameter from 50 to 5 nanometers, as a nanolens. This could be used to enhance Raman signals that could be used as sensors for detecting minute amounts of chemicals.
(12.10.03)
Magnetism: Mini magnets
(Physical Review Focus)
When ultra-pure graphite was irradiated with a 2.25 MeV proton beam, it was found to induce magnetic ordering and became magnetic under the influence of an applied field. It also retained some of this magnetism when the field was turned off.
(12.10.03)
Molecular Electronics: Molecular electronics confronts reality
(Nature Materials)
Organic molecular memories bound to silicon have been demonstrated to remain operational even after being baked at 400 °C and switched through a trillion read-write cycles.
(12.10.03)
November
Nanotubes: DNA delf-assembles nanotube transistor
(PhysicsWeb)
Self-assembly of DNA molecules has been used to build electronic devices from carbon nanotubes. The DNA acts as a scaffold for positioning a single-walled carbon nanotube at the heart of a field-effect transistor, as well as a template for the metallic wires connecting the device
(11.24.03)
Superconductivity Mechanisms: Condensates enter new era
(PhysicsWeb)
A Bose-Einstein condensate of bosonic molecules has been formed from a gas of fermionic atoms. If the atoms can be persuaded to form weakly-bound pairs, rather than molecules, physicists hope to learn more about the basic mechanisms responsible for superconductivity.
(11.24.03)
Focused Light : The sharpest focus
(Physical Review Focus)
Researchers have used radially polarized light from a helium-neon laser and focused it down to a point just 0.4 wavelengths across or about 0.06 square micrometers in area, compared with the theoretical limit of about 0.5 for linear polarization. This is a new record for the smallest focused spot. This tightly focused light produces an intense electromagnetic field that could be used as a probe or to manipulate atoms or other tiny objects.
(11.24.03)
Inkjet Printing: The optimal faucet
(Nature)
By tweaking faucet design and using a triangular nozzle in place of a circular one, researchers have discovered that for the same pressure, smaller droplets are formed. This is of significance for nozzles used in inkjet printing.
(11.21.03)
Optical Surfaces: Transparent ultra-water-repellant surfaces
(Nature Materials)
Researchers have developed a way to hydrophobize a surface of poly(ethylene terephthalate) (PET), while maintaining a high transparency. This is critical since now the optical properties of the PET remain unaffected by the presence of water.
(11.21.03)
Nanoimprint Lithography : Nanotransistors stamped out
(IEEE Spectrum)
Nanoimprint lithography literally stamps out a circuit. Previously used only in making simple non-electronic structures such as optical gratings, it has now been shown to be able to make electronics by nanoimprinting multiple transistors with features two-thirds the size of those found on even the most advanced commercial chips.
(11.21.03)
Fracture: Close-up on cracks
(Nature)
Fracture of materials at the microscopic level at the crack tip is still not well understood. Recent computational work shows that the material response to the large stresses that exist at the crack tip is nonlinear and a 'hyperelastic' force law applies. This hyperelastic region might be extremely small but its properties likely entirely control the fracture process.
(11.17.03)
Nanoscience: Gallium clusters are too small to melt
(AIP Physics News Update)
Nanoscopic clusters of Ga consisting of tens of Ga atoms were found to have much higher melting temperatures than bulk Ga. In fact, seventeen Ga atom clusters showed no signs of melting upto 800 K while bulk Ga melts at 303 K. No theoretical framework currently exists to explain this.
(11.17.03)
Biomaterials: Bone grows better on nanophase metals
(NanoTechWeb)
Osteoblasts or bone forming cells have been shown to adhere more easily to nanophase metals than to conventional smooth metal surfaces. This could be significant for coatings on medical implants.
(11.13.03)
Dendrimers: Dendrimers set to self-destruct
(Nature)
Dendrimers are branched macromolecules synthesized using repetitive chemistry. Several research groups are now exploiting their versatility and exploring their use as potential drug-delivery systems.
(11.13.03)
Organic Materials: WORM memory
(Nature)
An organic memory device based on a common electrochromic polymer PEDOT has been developed. The device is a write-once, read-many or WORM cell that is a low-power, low-cost alternative to conventional storage media such as CDs.
(11.13.03)
Nanowires: Nanowire
film brings cheaper, faster electronics a step closer
(Science Daily)
Harvard University researchers have been able to apply a film
of Si nanowires to glass and plastic surfaces to create functional
nanowire devices. They were able to do this without using the
usual high processing temperatures.
(11.10.03)
MEMS: Micro-Origami fabricated micromirrors
(AIP Physics News Update)
Japanese researchers have used a technique they call "micro-origami" to fabricate MEMS devices that automatically move into position. They have created hinged micromirrors that lift themselves up following the final fabrication stage. The key to the technique is to manufacture hinges out of a pair of material layers with lattice mismatch, which causes a stress that in turn bends the hinge and raises a mirror above the substrate.
(11.10.03)
Biomaterials: NMR
breakthrough for bone fracture
(PhysicsWeb)
A low field pulsed NMR has been used to determine porosity of
bone. This technique is non-invasive and non-destructive and
has great potential for bone related research and applications,
particularly for osteoporosis.
(11.10.03)
Lasers: Photonic
crystals boost semiconductor lasers
(PhysicsWeb)
A new type of laser has been created by embedding a photonic
crystal in the active region of a quantum cascade laser. The
photonic crystal acts as a microcavity providing feedback for
the laser action and also can diffract light vertically to allow
for vertical light emission.
(11.10.03)
Photodiodes: Silicon
sees the light
(Nature)
Researchers have developed a method to create a Si photodiode
using sulphur-doping and short laser-pulse irradiation. This
could be a significant development for optoelectronics.
(11.05.03)
Molecular
Electronics:
Molecular
electronic device shows promise
(Science Daily)
The first molecular resonant tunneling device on a semiconductor
has been demonstrated using individual molecules mounted directly
on Si. Resonant tunneling
may allow individual molecules to be detected and identified,
thus creating future opportunities for high sensitivity sensors.
(11.05.03)
Lubricant
films:
Thin
liquids get thicker
(Nature
Materials)
Researchers find that as
the thickness of a lubricant organic film approaches molecular
dimensions, viscocity rises dramatically. Increased molecular
ordering in the films was also observed.
(11.05.03)
October
2003
Nobel Prize in Physics
was awarded to
Alexei A.
Abrikosov, Vitaly L. Ginzburg and Anthony J. Leggett
"for pioneering contributions
to the theory of superconductors and superfluids"
Superfluidity: Nobel
focus: Helium impersonates a superconductor
(Physical Review
Focus)
Background on Anthony Leggett's work on 3He superfluidity that
won him this year's Nobel prize in Physics.
(10.31.03)
Micro-Machines: An
electrical micro-generator
(AIP
Physics News Update)
A micromotor with a 4-mm rotor has been developed which puts
out 20 milliwatts of power, far more than other existing rotating
micromotors. The motor, in effect a tiny jet engine, may be incorporated
into a microscale gas turbine generator.
(10.31.03)
Molecular Biology: The road from Biology to materials (PDF)
(Materials
Today)
The study of biology at the molecular level is leading to the
increasing use of biomolecules for the construction and synthesis
of new novel materials. "Molecular biology tool kits"
can now be used for new materials design.
(10.31.03)
Gold Plating: Gold
plating on the cheap
(PhysicsWeb)
A simple method based on ion implantation to inexpensively mass-produce
thin films of gold nitride has been developed. This could be
used in place of traditional gold plating in electronic components.
(10.28.03)
Terahertz
Imaging:
Terahertz
rays see into the nanoworld
(Nature
Materials)
Terahertz (THz) imaging is
being touted as the next big technology for imaging in biomedine
and engineering, as an alternative to X-rays, ultrasound and
magnetic-resonance imaging. It has now been demonstrated that
THz signals can be used in conjunction with scanning near-field
microscopy to circumvent the usual 'diffraction limit' on imaging
methods. This makes it possible to see below the diffraction
limit by a factor of about a thousand, resulting in nanometer-scale
resolution.
(10.28.03)
Membranolysis: Unhealthy
crystals
(Nature
Materials)
Crystals such as alpha-quartz
or calcium pyrophosphate dihydrate are toxic for biological membranes
and result in rupture and inflammation. Molecular dynamics simulations
now reveal the molecular mechanisms reponsible for the membrane
rupture.
(10.28.03)
Atomic
Weight:
Bicentenary
of atomic weights
(Nature
Materials)
It is 200 years since British
chemist John Dalton presented his Table of Atomic Weights at
the Manchester Literary and Philosophical Society.
(10.28.03)
Negative-Refractive Index Materials: Negative-index materials made easy
(PhysicsWeb)
Negative refraction in an ordinary crystal has been demonstrated
for the first time in a 'twinned' alloy containing yttrium, vanadium
and oxygen. This material contains two uniaxial crystals whose
optical axes are oriented symmetrically with respect to the interface.
The interface was found to refract light of any frequency and
electron waves as well.
(10.23.03)
Nanospectroscopy: The
travels of an exciton
(Physical Review
Focus)
Researchers have been able to track an exciton for the first
time. A 100 nm quantum dot was irradiated with laser light via
a glass optical fiber, and the same fiber was used to collect
the light released as an exciton formed and then disappeared.
The study also demonstrates that direct optical mapping of nanoscale
objects is within reach.
(10.23.03)
Radioisotopes: Lasers
may make PET scans cheaper
(Nature)
Proton beams can be produced
by shining a solid target with a very bright laser beam. It has
now been shown that such a set-up can produce carbon-11 and fluorine-18
radioisotopes in quantities close to those needed for Positron
Emission Tomography (PET) . The researchers used a relatively
cheap titanium-sapphire laser for this study.
(10.20.03)
Polymer Gels:
Monitoring
oscillatory gels
(Nature
Materials)
A polymer-gel system has
been developed that undergoes color changes when it exhibits
oscillations. This material could be useful for the study of
oscillatory gels that mimic materials in organisms that exhibit
self-sustaining oscillations, such as the peristaltic motion
of the intestinal tract.
(10.20.03)
Tissue Engineering: Embryonic
stem cells' support
(Chemical
and Engineering News)
Embryonic stem cells are
of significant interest since they have the potential to develop
into any type of cell. Now MIT researchers have shown that biodegradable
polymer scaffolds can be used to grow 3-D tissues from embryonic
stem cells.
(10.20.03)
Thermal Expansion: Zero expansion
plan
(Nature
Materials)
A new material, a metallic
compound of ytterbium, gallium and germanium, YbGaGe, shows zero
thermal expansion. YbGaGe is electrically conductive, Researchers
suggest that its lack of thermal expansion is due to the movement
of electrons from Yb atoms to Ga atoms as the temperature increases,
causing Yb atoms to shrink, but creating a negligible increase
in the size of Ga atoms.
(10.16.03)
Superfluidity: The
slightest splash of superfluid?
(Physical Review
Focus)
Researchers have been able to experimentally show that adding
just seven He atoms to an N2O molecule at temperatures
below 2.17 K results in superfluidity in the He. Six or less
He atoms still caused them to stick to the N2O.
(10.16.03)
Nanoscience: Nanoindenter cuts up
nanowires
(NanoTechWeb)
A nanoindenter has been used in conjunction with an AFM to measure
mechanical properties of a Ag nanowire. The technique was also
used to modify the shapes of the nanowires and even cut them.
The researchers indicate that this is the first time nanoindentations
have been made on a single nanowire.
(10.14.03)
Nanoscience: Gd atoms 'hop about'
in nanopeapods
(NanoTechWeb)
Japanese researchers have used high-resolution
transmission electron microscopy (HRTEM) to identify the rapid
movement of Gd atoms encapsulated in single walled carbon nanotubes,
for the first time.
(10.14.03)
Quantum
Dots:
Join
the dots
(Nature
Materials)
Researchers demonstrate logic
operations in circuits of nanoscale transistors made of quantum
dots that pass electrons one by one.
(10.10.03)
Liquid-Liquid
Transition:
A
tale of two liquids
(Physical Review
Focus)
A new theoretical study lends credence to the idea that two forms
of liquid water - a high density and a low density phase - exist.
The study also suggests that
any liquid that expands as it cools, such as water, must have
two distinct phases.
(10.10.03)
Photonic Crystals: Hot
crystal - Lightbulbs and a radiation law may never be the same
(Science
News)
New tungsten photonic crytal structures yield incandescent light
with significantly higher efficiency and higher intensities than
conventional tungsten lighbulbs and within a narrower spectral
range. They also seem to be violating Planck's law in the process.
(10.6.03)
Electronic Textiles: Ready
to ware
(IEEE Spectrum)
Textiles woven with conductive fibers and processors have numerous
potential uses in a variety of applications.
(10.6.03)
Sensors: Trapped
proteins find strength in numbers
(Nature
Materials)
A composite material in which several thousand protein molecules
are apparently packed into a nanoscale cluster and 'glued' within
a highly porous silica matrix might find applications for chemical
and biological sensing.
(10.3.03)
Superatoms: Magnetic
superatoms
(Nature
Materials)
Theoretical calculations were used to investigate the stability
of icosahedral Si, Ge and Sn clusters doped with divalent metals.
The researchers predict the existence of magnetic 'superatoms'
-- magnetic clusters of Ge and Sn formed by Mn doping.
(10.3.03)
Biomolecules/Inorganic
Crystals: Biomolecules call the
shots
(Chemical
and Engineering News)
Structural features of biological molecules were imprinted on
inorganic crystals using a biomineralization procedure based
on synthetic biomolecular templates. This new technique could
lead to custom-designed crystals with useful electronic, magnetic,
and optical properties.
(10.1.03)
Nanotubes: Nanotube
helium sensors could bring atom beam microscope
(NanoTechWeb)
A high-efficiency technique for detecting neutral atoms such
as helium has been developed. Multiwalled carbon nanotubes under
a positive bias were used to field-ionize passing He atoms, which
were then measured using a counter-electrode. This raises the
possibility of seeing spatial distributions of atomic beams in
two dimensions
(10.1.03)
September
Electronic Paper: Electronic paper reaches video speeds
(PhysicsWeb)
A new type of electronic paper has been developed that can display
moving images. Electrowetting was used as the basis for an electrophoretic
reflective display that uses voltage-controlled movement of a
colored oil film adjacent to a white display.
(9.29.03)
Ordering in Liquid Metals: Copper pentagons
(Physical Review
Focus)
Researchers have used x-ray absorption spectroscopy (XAS) and
advanced data-analysis techniques to probe liquid copper. They
show direct evidence of localized five-fold ordering in the liquid
copper.
(9.29.03)
Fullerenes: "Buckyballs"
may serve as effective material to process data
(The
Alchemist)
High-optical-quality polyurethane films containing a high number
density of C60 fullerene molecules have been synthesized
with the goal of obtaining enhanced nonresonant third-order optical
nonlinearity. The films yield excellent linear-absorption and
nonlinear-absorption characteristics at a wavelength of 1550
nm, which is the wavelength used to communicate information over
long distances.
(9.25.03)
Plasma: Proton
pulse gives proton possibilities
(Physical Review
Focus)
A team of researchers has used a new technique to create warm
dense plasma, which is a form of matter quite different from
other types of plasma. An intense, collimated, ultrashort-pulse
beam of protons was used to isochorically heat a solid density
material. The duration of heating was shorter than the time scale
for significant hydrodynamic expansion to occur and the material
was heated to a solid density warm dense plasma state.
(9.25.03)
Nanostructures: Molecular motors take DNA to the end of its tether
(Nature Materials)
Natural motor proteins have been shown to be able to manipulate
DNA molecules for stretching and moving them and for creating
DNA-based nanostructures.
(9.23.03)
Quantum Behavior: Molecules of life come in waves
(Nature)
Compounds found in biological cells have now been revealed to
show quantum behavior. Molecules containing porphyrin group,
the key ingredient of chlorophyll, show a wave-like interference
pattern when passed through an array of slits. The researchers
also showed wave-like interference for fluorinated C60 molecules.
(9.23.03)
Lasers: Single-atom
laser
(AIP
Physics News Update)
In a new study, a single-atom laser has been created that uses
a single trapped atom to resonantly emit light back and forth
between two reflective mirrors. This is the first time that a
single-atom nearly at rest has been used.
(9.19.03)
Metrology:
Silicon joins
race to redefine the kilogram
(PhysicsWeb)
The kilogram is the only SI base unit defined by a material object
- a piece of Pt-Ir alloy kept in a vault in Sèvres, France.
As part of an effort to redefine the kilogram in terms of atomic
or fundamental constants, an X-ray crystal density molar mass
(XRCDMM) method has been used to determine the lattice parameter,
density and molar mass of an almost perfect single-crystal of
silicon. The value of Avogadro's constant thus determined is
slightly different from the currently accepted value.
(9.18.03)
Fuel
Cells: A technically sweet fuel
cell
(IEEE
Spectrum)
A fuel cell that uses bacteria to convert sugar into electricity
has been developed. The microbe Rhodoferax ferrireducens can
metabolize glucose and other sugars into carbon dioxide, producing
electrons in the process. The electrons were collected by the
electrode and fed into an external circuit. Replenishing the
glucose kept up the flow of electrons.
(9.18.03)
Nanotubes: Nanotube
velcro
(AIP
Physics News Update)
Researchers have proposed nano-"velcro" systems using
carbon nanotubes. Nanotubes grown on two substrates with hooks
at the ends can be used to join the two substrates. [View
simulations]
(9.17.03)
Phosphorus
Superconductors:
Pressing
forward from teeth to superconductors
(AIP
Physics News Update)
New work shows that BCC Phosphorus, obtained when phosphorus
is subjected to high pressures, achieves superconductivity at
around 14-22 K, higher than for normal phosphorus. It might also
be possible to grow BCC phosphorus, without the need for high
pressures.
(9.17.03)
Carbon Nanotubes: Handling carbon nanotubes
(The
Alchemist)
A new method for separating metallic and semi-metallic nanotubes
from semiconducting ones by exploiting differences in electronic
structure is reported.
(9.15.03)
Granular Materials: Craters in a sandbox
(Physical Review
Focus)
Two groups have investigated the effects of dropping balls of
different materials onto sand and other granular media, and have
discovered that these impacts create craters very similar to
those found on the moon.
(9.15.03)
Nanoscale Materials: Slipping
and sliding
(Nature Materials)
Nanocrystalline grains of metals make the material harder and
less ductile with decreasing grain size. New computer simulations
now indicate that this hardening may decline or even reverse
for very small grain sizes.
(9.12.03)
Lubricants: Lubrication by charged polymers
(Nature)
Charged polymers are widely found in biological systems for biolubrication.
In a new study, charged polymers have been attached to mica surfaces
in an aqueous medium to form a brush-like layer that has excellent
lubrication properties.
(9.12.03)
Nanoparticles: Gold
lights up biological cells
(PhysicsWeb)
A new all-optical method has been developed to visualize proteins
in cells by labeling them with gold nanoparticles. The new 3-D
imaging technique is very sensitive and could help researchers
view the proteins efficiently and non-destructively.
(9.12.03)
Molecular Electronics: STM technique lets single-molecule junction be
prepared and imaged
(Chemical
and Engineering News)
Researchers have recorded the first direct image of a small molecule
confined between two metal contacts using an STM technique, and
have studied its electronic structure systematically.
(9.9.03)
Quantum Entanglement: Entanglement goes macroscopic
(NanoTechWeb)
The magnetic susceptibility of a single crystal of a simple magnetic
salt containing lithium, holmium, yttrium and fluorine, was found
to increase smoothly as the sample was cooled, in contrast to
its irregular heat absorption behavior. This was attributed to
a stronger contribution of quantum entanglement effects to the
susceptibility than to the heat absorption.
(9.9.03)
Carbon Nanotubes: Carbon nanotubes give out a steady glow
(NanoTechWeb)
Single-walled carbon nanotubes, studied using single-molecule
fluorescence spectroscopy, were observed to fluoresce with a
steady intensity and frequency, suggesting the possibility of
their application as stable infrared photon sources.
(9.9.03)
Laser Light Pulses: Bullets of light
(Physical Review
Focus)
A new technique has been reported that allows a "bullet"
or pulse of light to maintain its 3-D shape as it traverses through
a material. When a conventional laser pulse was directed into
a lithium triborate crystal, the pulse was spontaneously reshaped
into a nonlinear "X wave", which maintained its shape
using the nonlinear properties of a soliton.
(9.5.03)
Molecular Electronics: Decoupling the coupling group
(Nature Materials)
Charge transport measurements in single molecules are critical
for molecular electronics studies and are performed by fabricating
metal-molecule-metal junctions. A new study now unravels the
critical role of the metal-molecule bonding via a coupling group.
(9.5.03)
Raman Effect: Raman
effect brings Nano up to size
(The
Alchemist)
The popularity of Raman Spectroscopy has grown by leaps and bounds
over the last decade. In particular, it is proving to be a crucial
and unique tool for analysing nanostructured materials, since
most properties controlled by particle size, such as electrical
conductivity and mechanical properties, are correlated to Raman
parameters.
(9.5.03)
Organic Electronics: New
materials boost organic electronics
(Science News)
A new class of organic semiconductor molecules has been developed
that yields both n-type as well as p-type semiconductors. The
n-type organic semiconductors identified until now have been
rare and unstable. The new class of organics is based on a rod-shaped
organic molecule made of six thiophene units. Availability of
both p- and n-type molecules could hasten the development of
true organic electronic devices and circuits.
(9.2.03)
Microbatteries: Microbatteries patented
(Nature)
A technique to manufacture microbatteries in the size range of
micrometers has been developed. A fine aluminum oxide honeycomb
material is used to create plastic electrolyte with electrodes
placed at the ends of the pores.
(9.2.03)
Hydrogen Storage: Materials for hydrogen storage (2.5 MB PDF)
(Materials
Today)
Six different hydrogen storage methods are described in this
review. Materials are a key for the development of hydrogen storage
techniques. The major challenge is to better understand interaction
of hydrogen with other elements, especially metals.
(9.2.03)
Tomography: Quantum
effect improves tomography
(PhysicsWeb)
Using "Quantum" Optical Coherence Tomography (OCT),
the resolution of OCT has been improved by a factor of 5. The
new quantum technique uses two "entangled" photons
produced when a 406 nm beam from a krypton-ion laser strikes
a lithium iodate crystal. OCT is used to produce optical cross-sections
of biological tissues.
(9.2.03)
August
Nanoparticles Structure: Wet nanoparticles alter their atoms
(NanoTechWeb)
The structure of nanoparticles appears to be environment-specific.
A new study shows that adding water to 3nm-sized ZnS nanoparticles
reduced distortions on the surface and interior of the particles,
yielding a more crystalline arrangement of atoms wihin.
(8.29.03)
Nanotubes: Nanotubes
boost ceramic performance
(NanoTechWeb)
A new carbon nanotube-alumina composite has been developed that
has a 13 orders of magnitude higher electrical conductivity than
pure alumina. The nanotubes were found to self-organize into
"ropes" held together by van der Waals forces that
were entangled within the alumina grains and the improved conductivity
was a result of these ropes forming a continuous, interlinked
electrical pathway throughout the composite.
(8.29.03)
Nanotubes: Aluminum
nitride nanotubes
(The
Alchemist)
The synthesis and characterization of single-crystalline faceted
hexagonal aluminium nitride nanotubes has been reported in a
paper published in the Journal of the American Chemical Society.
The nanotubes had diameters of 30-80 nm and were a few microns
in length.
(8.29.03)
Diamonds: Diamonds from dry ice
(Nature Materials)
Using chemical reduction of dry ice, by heating solid CO2 to
440 °C at a pressure of 800 atmospheres in a sealed container
with sodium metal, researchers obtained irregular but crystalline
diamond particles of about 100 µm or so, along with octahedral
crystallites about 10 µm in size.
(8.25.03)
Molecular Electronics: Getting wires crossed for nanocomputing
(Nature Materials)
Simple 'wet-chemical' Langmuir-Blodgett techniques have been
used to fashion semiconducting nanowires into organized, hierarchically
structured arrays suitable for creating high-density electronic
logic circuits and memories. Criss-crossing "cross bar"
nanowire arrays have been developed, which can serve as devices
for nanoscale logic and memory circuits.
(8.25.03)
Molecular Electronics: Rapid Assembly -- Method forms ordered, nanosized
circuit elements on multiple length scales
(Chemical
and Engineering News)
A solution-based method for assembling nanowire structures from
the bottom up with spatial control on several length scales,
ranging from nanometers to centimeters, has been developed. Large
numbers of uniform and hierarchically ordered nanoscale circuit
elements have been prepared simultaneously using a simple and
adaptable technique.
(8.25.03)
Molecular Screening: Off-the-shelf CDs, CD players used to probe biomolecular
interactions
(Chemical
and Engineering News)
A new technique has been developed in which commercially available
compact discs (CDs), CD players, and CD computer drives can be
used to monitor biomolecular interactions could lead to inexpensive
molecular screening devices. It creates protein microarrays on
CD surfaces and uses CD players to "read" them.
(8.25.03)
Quantum Devices: Microscope
sketches quantum devices
(PhysicsWeb)
A new method to create quantum electronic devices using an atomic
force microscope has been developed. The technique, known as
erasable electrostatic lithography, allows researchers to create
and change quantum devices and circuits during an experiment
. Erasable lithography could also be used in experiments to study
quantum phenomena and may provide a route to the fabrication
of a solid-state quantum computer
(8.21.03)
He Molecules: Giant
He molecules
(AIP
Physics News Update)
Using magnetic fields to trap helium atoms at ultralow temperatures
close to 10 microkelvins, researchers have been able to create
giant helium molecules, containing only two atoms but assuming
a size as large as a small virus. The sizes of the molecules
ranged from 10 to 100 nanometers. They are the largest diatomic
(two-atom) molecules ever created, by a factor of 5, and are
comparable to the size of viruses, which vary in length from
5-300 nm.
(8.21.03)
Nuclear Waste:
Lasers tackle
radioactive waste
(PhysicsWeb)
A laser has been used to transmute isotopes for the first time.
The laser pulse was directed at a gold target, which emitted
gamma rays as bremsstrahlung radiation. The gamma rays were used
to eject a neutron from Iodine-129 (half-life of 15.7 million
years) and trasmute to Iodine-128 (half-life of 25 minutes).
This has significant impact for the treatment of nuclear waste
as well as for production of medical isotopes.
(8.13.03)
Archeology: Archeology
turns to superconductivity
(PhysicsWeb)
A new technique, based on superconductivity and measurement of
magnetization of lead, has been developed to date archeological
artifacts. Since lead corrodes very slowly, the amount of corrosion
products can be determined which can be correlated directly with
the age of the lead.
(8.13.03)
Military Applications: Science transforms the battlefield
(Chemical
and Engineering News)
Recent advances in materials technology are providing military
personnel with ever-improving combat capabilities and levels
of protection.
(8.11.03)
Femtosecond Electron Diffraction: Recording atomic vibrations
(Nature Materials)
An electron-diffraction system has been developed that is capable
of measuring transient structures in solids on the 400 femtosecond
time scale. Electron diffraction images have been obtained that
are good enough to reveal long-range lattice order with only
a single electron pulse containing around 4,000 electrons.
(8.11.03)
Superconductivity: Lifting the Gossamer veil
(Nature Materials)
High-temperature superconductivity (at about 90 K) occurs in
insulating copper oxide ceramics when small amounts of charge
are injected by chemical doping. A new theoretical study now
unifies alternative views of how high-temperature superconductivity
is linked to an insulating state of matter. As per this, an undoped
copper oxide superconductor can, under certain conditions, transform
from its insulating state into an extremely delicate state of
'gossamer' superconductivity.
(8.11.03)
Nanotubes:
Tiny nanotubes
set new record
(NanoTechWeb)
The smallest free-standing single-walled carbon nanotubes to
date, measuring around 0.43 nm in diameter, have been created.
A nanozeolite floating-reactant chemical vapour deposition method
was used. In this technique, the zeolite powder limits the size
of the catalytic iron particles and also operates as a support
for the catalyst and as a floating substrate.
(8.7.03)
Spintronics: Molecules
build a bridge to spintronics
(NanoTechWeb)
Researcher have been able to transfer electron spins across molecular
'bridges' between quantum dots for the first time. They found
that they could transfer the spins most effectively at room temperature
(8.7.03)
Molecular Electronics: Well connected
(Nature Materials)
Electrical contacts between molecular components is critical
for molecular electronics. Now, scanning tunnelling microscope
(STM) has been used to manipulate and probe a short, linear polyaromatic
molecular wire, called a Lander, sitting on the surface of copper.
(8.5.03)
Organic Electronics: Organic
devices get back on track
(PhysicsWeb)
Organic single-crystal field-effect transistors have been developed
with electron mobilities higher than the best thin-film devices
made from the same material. Single crystals of tetracene - a
molecule that contains four linked carbon rings - were attached
to a silica, without damaging the crystals, onto which gold source
and drain electrodes had already been deposited. The crystals
- less than a micron thick - strongly adhere to the substrate
without the need for any further processing steps.
(8.5.03)
Nanowires: The
nanowire is the solution
(ChemWeb)
The large-scale fabrication of single-crystal selenium nanowires
by the solution-mediated treatment of polycrystalline selenium
powder is reported. The resulting selenium nanowires are found
to form from a dissolution recrystallization mechanism.
(8.1.03)
Single-Molecule Raman Spectroscopy: Reflecting on Raman
(ChemWeb)
A new study investigates the structural basis for giant enhancement
enabling single-molecule Raman scattering. It was observed that
giant surface-enhanced Raman scattering for adsorbates on silver
surfaces is present only on surfaces that exhibit self-similar
fractal topology as inferred from atomic force microscopy, and
not for non-fractal surfaces.
(8.1.03)
Nuclear Materials: Stability of plutonium dioxide
(ChemWeb)
A new study shows that PuO2, widely used for Pu storage, may
deteriorate upon long term storage. Quantum mechanics calculations
indicate that other oxidation states are possible with the insertion
or extraction of oxygen, leading to Pu(V) and Pu(III), respectively.
(8.1.03)
July
Nanoparticles: Nanoparticles
spy on molecular binding
(NanoTechWeb)
Scientists report the creation of the first single metal nanoparticle
sensor based on light-scattering spectroscopy. The technique
was demonstrated using a gold nanoparticle functionalized with
biotin to detect the presence of the protein streptavidin.
(7.30.03)
Photonic Crystals: Carving a path for light
(Nature Materials)
An argon ion-laser has been used to create waveguides in Si colloidal
photonic crystals. These could be used in integrated optoelectronic
devices. The laser can also be used to create other structures
including spot defects, junctions, refractive index gradients
and periodic superlattices.
(7.30.03)
Polymer Lasers: Coaxing
light beams out of cheap plastic
(Science
News Online)
Researchers create lasers made from polymers by imprinting patterns
onto them using a hard mold with nanometer sized ridges and features.
(7.28.03)
Diamond Films: Milling
diamond films
(AIP
Physics News Update)
Researchers have used a focused gallium ion beam to micromachine
diamond thin films.
(7.28.03)
MEMS: World's smallest electric rotor made
(Nature)
Researchers have created what could be the smalles electric rotor
ever made. Its gold blade is 300 millionths of a millimetre long.and
the axle is made from a multiwalled carbon nanotube. Gold electrodes
at either end of the axle lash the device to a silicon chip.
(7.24.03)
Nanotechnology: Device measures femtometers
(Chemical
and Engineering News)
Anew sensor that can measure femtometer-sized movements
of a single-crystal oscillator has been developed. It consists
of a single-electron transistor coupled to a vibrating, 250-nm-wide
beam of GaAs. This places it within striking distance of observing
the effects of the Heisenberg uncertainty principle on a macroscopic
object.
(7.24.03)
Courtesy: IBM
Creep:
Nanoparticles
reinforce steel
(PhysicsWeb)
By adding just 0.002% carbon to a martensitic steel, researchers
were able to increase the time-to-rupture at 923 K by a factor
of 100 over the strongest creep-resistant steel currently available
(which contains about 0.08% carbon). They attrtibute this to
the formation of 5-10 nm particles that strengthen the matrix.
(7.21.03)
Superconductors: A
very tolerant superconductor
(Physical Review
Focus)
Researchers demonstrate that milling a superconducting PbMo6S8
material into nanometer sized grains and reforming it into a
chunk of material significantly increased its magnetic tolerance
(critical field).
(7.21.03)
Photonic
Crystals: Turning heat into electricty
- and Planck's law be damned
(ChemWeb)
Working with a three-dimensional tungsten photonic-crystal lattice,
scientists have greatly improved the efficiency and power density
for thermal photovoltaic power generation. In the process, they
also appear to have 'violated' Planck's Law.
(7.17.03)
Photonic Crystals: Photonic cystal shifts energy
(AIP
Physics News Update)
A photonic crystal made from half-micron-diameter tungsten rods,
and excited by thermal heating, appears to suppress light at
longer wavelengths and re-emits light at a shorter wavelength.
(7.17.03)
X-Ray
Crystallography:
Picosecond
x-ray crystallography of a protein
(AIP
Physics News Update)
Picosecond x-ray crystallography of a protein is demonstrated
for the first time. Due to the picosecond time scale, it is possible
to generate atom-scale movies of the protein at work.
(7.17.03)
Glasses: Improved Synthesis of Sodium Aluminophosphate
Glasses
(ChemWeb)
A lower temperature, and lower cost route to the synthesis of
aluminophosphate glasses using a sol-gel route is reported. While
traditional process temperatures are in the 1300C range, the
sol-gel process temperature is in the 400 C range.
(7.17.03)
Hardness:
Chipping
away at hardness
(Physical Review
Focus)
A Chinese team of researchers has developed a semi-empirical
model to predict hardness of a material based on ionicity, bond
length and number of electrons available for bonding. The model
was used to correctly predict, within a 10% accuracy, hardness
values for 14 different oxides, semiconductors and covalent materials.
(7.14.03)
Liquid Crystals: Switching liquid crystals with light
(Nature Materials)
The first morphologically stable photoresponsive glassy liquid
crystals have been reported. Irradiation of the film with ultraviolet
light converts the photoresponsive core molecules from an open-ring
form to a closed-ring form which results in a large refractive
index change.
(7.14.03)
Nanotubes:
Nanotubes
get sorted
(Nature
Materials)
Two research teams have come up with a solution to the problem
of separating metallic and semiconducting carbon nanotubes, both
of which are formed during synthesis. The first uses a technique
similar to electrophoresis to pull metallic and semiconducting
species in opposite directions. The second uses protonation and
separation based on differing pH values.
(7.14.03)
Metamaterials: Left-handed materials go from fact to fiction
and back again
(IEEE Spectrum)
Recent experiments suggest that negative-refraction-index materials
may indeed be a possibility. This is a reversal from recent opinions
that such behavior had been misinterpreted in past studies.
(7.14.03)
Metamaterials: Nanocrystals
double up
(PhysicsWeb)
New self-assembling metamaterials have been created using lead-selenium
semiconductor quantum dots and iron oxide magnetic nanocrystals.
(7.9.03)
Superconductors: Mottness might help explain cuprate behavior
(AIP
Physics News Update)
Cuprate superconductors are good superconductors in the cold
regime but become "Mott" insulators in the warm regime
(all electron energy states are filled with single electrons,
and these interact so strongly as to preclude even the arrival
of a second electron). A new theory explains why this could be
so and relates the "Mottness" to pseudogaps (a partial
energy gap that persists even when superconductivity is destroyed
).
(7.9.03)
Optoelectronics: Single-nanotube photodetector
(Chemical
and Engineering News)
Scientists have been able to detect and measure electrical current
in a single nanotube by shining light on it. A field effect transistor
with a single nanotube acting as the semiconducting channel was
constructed for this purpose.
(7.9.03)
Solidification: Experiments vindicate a 50-year-old explanation
on how liquid metals resist solidification
(Physics Today)
It has been known that liquid metals can be significantly undercooled
without solidifiying. Frank, in 1952, hypothesized that liquid
metals possess short-range order based on the icosahedron. Researchers
have now provided experimental proof for this by using electrostatic
levitation and a third-generation schrotron source to study the
solidification of a Ti-Zr-Ni system.
(7.2.03)
Biomaterials: Bone mimic makes anti-decay fillings
(Nature)
A new smart cement that could be used for treating damaged teeth
or as fillings helps fend off tooth decay. It incorporates amorphous
calcium phosphate blended with silicon or zirconium.
(7.2.03)
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