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2003
Special Feature
Space Shuttle Columbia Disaster - Materials
Issues
Courtesy: NanotechWeb.org
Nanotubes/Ionic
Liquids: Ionic liquids go Bucky (from Chemical and Engineering News)
Japanese researchers have prepared "bucky gel" materials
by grinding suspensions of high-purity single-walled carbon nanotubes
in imidazolium cation-based ionic liquids in an agate mortar.
The gels can be processed into various forms and have the potential
for making new electronic devices, coating materials and antistatic
materials. (6.30.2003)
Molecular Beam
Epitaxy: Mountain-climbing atoms (from AIP Physics News Update)
[see image]
Under specific conditions, Al atoms deposited on thin films using
molecular beam epitaxy (MBE) are seen to diffuse up crystal protrusions
forming larger "mountain"-like structures. This could
be crucial for other systems grown using MBE and results in richer
thin film growth dynamics. (6.30.2003)
Acoustics: Music
of the spheres (from Physical Review
Focus)
The English mathematical physicist Horace Lamb analyzed and predicted,
in 1892, two acoustical vibrational modes for a solid sphere.
Now, researchers have used silica nanospheres and Brillouin scattering
of a laser light to verify Lamb's theoretical predictions. (6.30.2003)
Nanotechnology: DNA
nanostructures make up bar code (from
Nanotechweb)
A bar code pattern containing digital information has been created
by using DNA assembly around a synthetic "scaffold"
strand of DNA. This forms a 2-D bar-code patterned lattice. (6.26.2003)
Fullerenes: Geological
fullerenes -- Buckyball clue to dinosaur extinction (from ChemWeb)
Fullerenes have been found in meteorites and could provide definitive
evidence for the meteorite impact theory of mass extinction on
earth. (6.26.2003)
Nanowires: Defect
engineers wire up nanowires
(from ChemWeb)
Researcher have grown conducting nanowires in a non-conducting
crystal of sapphire. This has been accomplished by engineering
defects in the sapphire and doping. (6.26.2003)
Storage: New
heights for hard drives (from
Materials
Today)(PDF)
A review of the developments in hard drive technology from a
materials perspective is presented. Hard disk drives remain the
primary mass storage device in computers. The first disk drive
developed in 1957 had a storage density of 2 kbit/in2. Current
drives have a capacity of 60 Gbit/in2. Prototypes with recording
densities of up to 150 Gbit/in2 have been developed. (6.26.2003)
Thermometry: Noise thermometer accurate at frigid extremes (from Nature)
A new thermometer for measurements of cryogenic temperatures
close to absolute zero has been developed. It relies on "shot
noise" produced by electrons tunneling through a barrier.
It has excellent accuracy and precision, and is a primary thermometer,
so it can be used as a reference thermometer for calibration.
(6.23.2003)
Nanoparticle
Actuators: Nanoparticles get smart (from Nature Materials)
16 nm nanoparticles of gold have been crosslinked to form porous
films which were deposited on porous polycarbonate support forming
a bilayer structure. These strips act as robust actuators under
the influence of electric potential when placed in a potassium
chloride solution. (6.23.2003)
Quantum Dots: Rings of excitement
(from Nature
Materials)
Tailored polypeptides have been used to organize inorganic calcium
selenide quantum dots into microscopic laser cavities. (6.23.2003)
Tissue Engineering: Making plastic bones to save limbs (from ChemWeb)
To replace crushed or severely damaged limbs, a microporous calcium
phosphate coated polymer "bone" material has been created.
The material is an interpenetrating network of slowly degrading
polybutylene terephthalate coated with rapidly degrading tricalcium
phosphate to which bone cells can attach themselves. Individually
tailored using rapid prototyping techniques, the implanted material
has real bone material growing through the scaffold and is expected
to completely replace the implanted material. (June 19, 2003)
Sensors: Chemistry makes smart bricks (from ChemWeb)
A prototype smart brick that can monitor a building's temperature,
vibration and movement, and relay this to a different location
has been developed. It incorporates a thermistor, an accelerometer,
multiplexer, transmitter, antenna and battery. (June 19, 2003)
Silicon Defects: Defect Theory -- Elusive State-of-the-art (from Materials Today)(PDF)
Defects play a critical role in semiconductor electronics. Modern
electronics depend on defect engineering at theatomic level.
This paper reviews the historical development and new advances
in defect theory in silicon. (June 19, 2003)
Self Assembly:
Gear change
for miniature machines (from
Nature)
Miniature plastic gears and cogs, several millimeters across,
floating on an organic fluid (perfluorodecalin) were found to
be able to self-assemble into devices in which they can be made
to rotate. (June 17, 2003)
Photonics:
Light gets
a useful shock (from Nature
Materials)
A shock wave passing through a photonic crystal is shown to do
strange things to light. There is a shift in frequency. The light
is temporarily trapped at the shock front before being re-radiated.
Also, the bandwidth of the reflected light is narrowed without
any energy loss. (June 17, 2003)
Nanotubes: Spring-loaded nanotubes
(from Nature
Materials)
Simulations indicate that when multiwalled carbon nanotubes are
'telescoped' and then released, they act like spring-loaded shock
absorbers. Results show that DWNTs can act as nanoscale oscillators
and vibration dampers and their properties (such as frequency
and damping rate) can be fine-tuned if the molecular structures
of the tubes can be controlled. (June 17, 2003)
Hydrogen Storage: Holey fullerene opens
wide for H2 (from Chemical and Engineering News)
An open-cage fullerene derivative has been prepared with an orifice
large enough to allow a hydrogen molecule to be inserted into
the cage in 100% yield. This could be used for future hydrogen
storage applications. (June 16, 2003)
Nanotubes: A carbon nanotube composite fiber (from AIP Physics News Update)
Single-walled nanotubes were injected into a pipe filled with
polyvinyl alcohol to form a gel, which can then be spun out into
strands to form carbon nanotube composite fibers. (June 16, 2003)
Tomography: In
industry, seeing is believing
(from PhysicsWeb)
Electromagnetic tomography is now widely used in various industrial
settings to image and optimize various processes. (June 16, 2003)
Organic Chemistry: A gate to organokrypton chemistry: HKrCCH (from Nature)
An organic compound containing the inert gas Krypton has been
synthesized by incorporatingn Kr into acetylene. (June 11, 2003)
Molecular Cell
Biology: Tracking atoms into
the fold (from Nature)
The positions and movements of all atoms in small proteins can
be tracked as they fold and unfold thereby yielding a good understanding
of the mechanism of protein folding. Researchers have used experiments
in conjunction with atomic-scale moleculer dynamics simulations
to accomplish this. (June 11, 2003)
Friction: Frictional Coupling between Sliding and Spinning
Motion (from Physical Review Focus)
It has been known that for a rotating disk sliding across a surface,
the spinning ans sliding motions come to a halt simultaneously.
A new theoretical analysis now provides an explanation for this
phenomenon. There is a coupling of linear and rotational friction
such that the combination of the two converge to the same endpoint.
(June 11, 2003)
Tissue Engineering: Human arteries grown from scratch (from Nature)
Human arteries have been grown from scratch in the laboratory
for the first time. These were created using human muscle cells.
(June 11, 2003)
Hydrogen: Hydrogen
goes universal (from PhysicsWeb)
A "universal alignment" effect has been calculated
for the transition energy of hydrogen in different materials
and has been found to be the same in a wide variety of different
materials. This allow for the prediction of electrical behavior
of hydrogen in different materials. (June 9, 2003)
Quantum Dots: Quantum
dot advances (from Chemical and Engineering News)
Quantum dots are moving closer towards biological applications,
as suggested by two recent research reports. In the first, quantum dots have been
used as a label for multiphoton imaging in live animals. In the
second report, chaperone proteins have been used to encapsulate
and protect quantum dots, preventing them from aggregating and
losing their size-dependent properties. (June 9, 2003)
LEDs:
Red hot (from IEEE Spectrum)
A profile of the red LED, the first laser diode, and its inventor,
Nick Holonyak Jr., who is the 2003 IEEE Medal of Honor winner.
Related Article: The
Diode Laser-the First Thirty Days Forty Years Ago, R. D.
Dupuis, IEEE LEOS (February 2003). (June 9, 2003)
Tribology: Water complicates nanoscale friction (from Nature Materials)
Friction at the nanoscale can be complicated by the condensation
of water at asperities. This adds a component to the force between
two surfaces, thereby affecting friction. (June 6, 2003)
Adhesion: Lizards help adhesive design (from Nature Materials)
Scientists have used the design of the geckos' toes as a model
to create an adhesive tape that contains millions of protruding
polymer "hairs". The "super sticky" tape
is strong enough to stick a person to a ceiling by just one hand.
Van der waals forces are responsible for sticking to dry surfaces
while suction-type capillary forces assist in the adhesion on
wet surfaces. (June 6, 2003)
Spintronics: Spin
currents -- free of charge
(from Physical
Review Focus)
Two research groups have independently produced pure spin currents
without associated electrical currents. (June 4, 2003)
Courtesy:
Institute of Physics
Transparent Oxides: Transistors go transparent (from PhysicsWeb)
Researchers have created a transparent field-effect transistor
made from a single crystal thin film oxide semiconductor that
is ten times faster than similar previous devices. (May 30, 2003)
Metal Clusters: Non-metallic metals (from
ChemWeb)
Clusters of upto 200 Niobium metal atoms have been shown, at
low temperatures, to demonstrate non-metallic characteristics
including creation of ferroelectric dipoles. This has been labeled
a new phase of metallic matter. (May 30, 2003)
Crystals: Crystal: in search of clarity (from Nature Materials)
What exactly is a crystal and how can it be defined? The issue
appears to not be how one defines a crystal but how one defines
"order." The scope and meaning of the term "crystal"
will likely evolve and expand as we move towards systems of greater
complexity and diversity. (May 30, 2003)
Plasma: Solid Slate Plasma
(from AIP
Physics News Update)
A solid state plasma made of Beryllium ions remained in a solid
state form for a few nanoseconds. (May 27, 2003)
Standards: Scientists struggling to make kilogram right again (from New
York Times)
The kilogram is currently defined by a platinum-iridium cylinder,
cast in England in 1889 and in storage now in France. This appears
to have lost about 50 micrograms. Scientists are now working
on creating a new standard for the kilogram using a perfectly
round crystal of 99.99 % pure silicon 28. They hope to define
the standard by the precise number of atoms in the crystal. (May
27, 2003)
Courtesy: Institute
of Physics
Thermoelectric Materials: Thermopower in a spin
(from PhysicsWeb)
Thermoelectric Materials: Thermopower to the people
(from Nature Materials)
Previously, a layered sodium cobalt oxide thermoelectric material
has been shown to have a cooling capacity ten times that of metals.
Researchers have now showed that spin entropy current might be
very significant for the enhanced thermoelectric properties of
this material. As anticipated, the thermopower was found to be
suppressed when a magnetic field was applied in the plane of
the layered-oxide material, blocking the motion of the spins.
(May 22, 2003)
Hydrogen Storage: Hydrogen stored in nanoscale framework (from Nature Materials)
A new class of nanoporous materials created with metal-organic
frameworks using molecular design shows impressive hydrogen storage
capacity. They consist of oxygen-centred tetrahedral zinc clusters
(OZn4) at the vertices of a cubic framework, each coordinated
to six carboxylate groups in the organic linkers. These linkers
are linear dicarboxylates with an aromatic centre. (May 22, 2003)
Drug Delivery: Turning bubbles into microscopic syringes (from AIP Physics News Update)
Acoustically driven metamorphosis of bubbles into micro-syringes
has been demonstrated. Bubbles of sizes ranging from 7 to 55
microns were subjected to shock waves. The bubbles were compressed
to a needle shape while introducing a nanovolume quantity of
the surrounding liquid which shot through the needle shape and
emerged in the form of a high-speed stream from a punctured end,
similar to a syringe. This could conceivably be used to inject
very tiny amounts of dissolved drugs or genetic material into
a cell. (May 19, 2003)
Superconductivity: Nanoengineered
Magnetic-Field-Induced Superconductivity (from Physical
Review Focus)
A nanoengineered lattice of magnetic dots on top of a superconducting
film has been used to srongly enhance the perpendicular critical
fields of the film. This allows for magnetic field-induced superconductivity
in these hybrid superconductor/ ferromagnet systems. (May 19,
2003)
Magnetic Materials: Cobalt
breaks magnetism record (from
PhysicsWeb)
Cobalt atoms on a platinum substrate have been measured to have
a magnetic anisotropic energy (MAE) of over 9 meV per Co atom.
This is the largest magnetic anisotropy ever measured. By comparison,
a widely used permanent magnet, samarium cobalt, has an MAE of
just 1.8 meV per Co atom. This could lead to the development
of new high density magenetic storage materials and could also
lead to a better understanding of nanomagnetism. (May 19, 2003)
Magnetic Materials: Researchers develop magnetic probe for rocks (from ChemWeb)
A new technique called First Order Reversal Curve (FORC) has
been developed to study magnetic properties of rocks and sediment
formations, as well as new materials being developed in the lab.
The technique subjects a material to a series of magnetic field
and measures the response. Geologists are using FORC to determine
how magnetic signals are recorded in socks and sediments, and
this can be extended to new magnetic materials under development.
(May 19, 2003)
Geomaterials:
Probe could
ride to Earth's core in a mass of molten iron
(from Science News Online)
A new technique for direct observation of and measurement of
the properties of the earth's core has been suggested. An instrument
surrounded by molten iron, if placed in a surface fissure at
least 300 meters deep, would form a self-propagating crack that
would progress at roughly 5 m/s and would reach the outer core
in about a week. (May 19, 2003)
Negative Refraction Materials: The reality of negative refraction (from PhysicsWeb)
Recent studies appear to support the existence of negative refractive
index metamaterials. The notion of negative refraction, however,
often leads to consequencies that go against intuition. This
is a rapidly evolving field and further developments are anticipated.
(May 16, 2003)
Dip-Pen Nanolithography: Nanolithography: Rewriting the rules (from Materials Today)(PDF)
Dip-pen lithography is generating a lot of interest because of
its ability to pattern surfaces with miniaturized molecular arrays.
Research is currently under way to investigate the potential
of the technique for real applications. (May 16, 2003)
Displays: Slim screen can be rolled but not folded (from Nature)
An ultra-thin electronic-ink display screen with the screen
less than 0.3 mm thick, flexible enough to be rolled into a tube
just 4 mm across and viewable from almost any angle has been
developed. (May 13, 2003)
LEDs: LEDs get on the right wavelength (from Nature)
GaAs LEDS have been created incorporating arsenic antisite defects,
that emits light with a longer wavelength than usual which is
more compatible with long-distance fiber optic networks. (May
13, 2003)
Space Science: Space glass cracks earthly limit (from Washington
Times)
Manufacturing glass in a zero-gravity environment can have significant
consequences for the properties of the material. For example,
glass made of ZBLAN, a blend of fluorine and Zr, Ba, La, Al,
and Na is 100 times more transparent than silica-based glass.
It is very difficult to produce on earth but appears to be amenable
to manufacture in near zero-gravity in space. (May 13, 2003)
Granular Mixtures: Controlling Cohesive Particle Mixing and Segregation
(from Physical Review Focus)
A mathematical expression for the force acting between any pair
of particles has been developed, accounting for size, density,
and each particle's affinity for water. To predict whether two
types of particles would mix or separate, the strength of attraction
between pairs of identical particles was compared with that of
mismatched pairs. If the mismatched pairs had higher attraction,
thorough mixing was predicted; otherwise the particles are expected
to segregate. (May 9, 2003)
Courtesy:
American Institute of Physics
Crystals: Perfect insulin crystals (from AIP Physics News Update)
[See
image]
Insulin proteins crystallizing around a screw dislocation defect
in an existing insulin crystal were found to form spiraling hillocks
of perfect crystalline insulin. This has implications for growing
perfect crystals for various applications. (May 9, 2003)
Carbon Nanotubes: The
tiniest solid-state light emitter
(from AIP
Physics News Update)
The tiniest solid-state light emitter has been produced, consisting
of a single-walled carbon nanotube strung between two electrodes,
and controlled by a third. The business part of this minuscule
transistor is a nanotube only 1.4 nm wide and tailored to be
semiconducting. (May 9, 2003)
Nanotubes: Nanoscale
Networks: Superlong nanotubes can form a grid (from Science
News Online)
Researchers report growing the longest individual carbon nanotubes
ever, upto 4 mm in length, and aligning them in a two-dimensional
grid. (May 9, 2003)
Atom Manipulation: How to grab an atom
(from Physical
Review Focus)
Researchers have used a silicon AFM tip to capture a single Si
atom from an Si surface and then place it back on the surface
at a specific location. This represents the first time that atome
manipulation has been demonstrated on a non-conducting surface.
(May 5, 2003)
Carbon Nanotubes: Capped on (from
Nature
Materials)
For nanotube growth using a catalyst, first-principles calculations
show that in the presence of a metal surface, nucleation of a
cap or a capped tube is overwhelmingly favoured over a graphene
sheet, a fullerene, or an open tube. (May 5, 2003)
Nanowires: Carbon nanowires
(from AIP
Physics News Update)
[See
figure]
Carbon nanowires, a one-dimensional string of carbon atoms within
a carbon nanotube, have been observed for the first time. (May
2, 2003)
Superconductors: Multiple gaps (from
ChemWeb)
Experiments have confirmed that magnesium diboride possesses
two types of superconducting gaps.The superconducting gaps of
sigma and pi bands in MgB2 have been eludicated using high-resolution
angle-resolved photoemission spectroscopy (ARPES). (May 2, 2003)
Photonic Crystals: Shocking color effects
(from AIP
Physics News Update)
Computer simulations suggest two new effects in a photonic crystal
subjected to a shock wave: a Doppler shifting hundreds or thousands
of times larger than usual and a narrowing of the bandwidth.
(May 1, 2003)
Nanotubes/Interconnects: Nanotubes grown to wire chips (from Nature)
Researchers have grown vertical carbon nanotubes at specific
locations on a silicon chip and have been able to surround them
with insulating silicon dioxide. This represents a bottom-up
approach to fabricating interconnects on chips. (May 1, 2003)
Minerology: Eye
of the Tiger (from Science News Online)
Tiger's-eye is a gem that exhibits chatoyancy -- when polished
and illuminated, it reflects a narrow band of light that changes
position as the gem is turned back and forth. A new investigation
has now overturned the 130-year old theory for the cause of this
effect. (May 1, 2003)
Nanotubes:
Single-crystal
gallium nitride nanotubes
(from Nature
Materials)
A new "epitaxial casting" technique is reported that
allows for the growth of single-crystal gallium nitride nanotubes.
This could be used for making nanotubes from other semiconducting
materials as well. The researchers first developed a process
for growing arrays of single crystal ZnO nanorods, which were
used as templates to form the GaN nanotubes. (Apr.15, 2003)
Nanostructures: A
fine point on carbon (from
Nature
Materials)
A new nanostructure - nanopipette - has been reported by researchers.
Made from carbon, it tapers to an almost atomically fine tip.
it has a hollow core just 1-3 nm wide. One of the applications
envisaged for this structure is a miniature hypodermic microneedle
for precision drug delivery applications. (Apr.15, 2003)
Superconductivity: Momentous imaging
(from Nature
Materials)
In a recent study, scanning tunneling microscopy has been used
to probe the wave-like correlations that exist in the nanoscale
variations in the electronic structure of a cuprate superconductor.
This work goes some way in answering questions about the nature
of the two carrier phases in high-Tc superconductors and
provides an important tool for future work. (Apr.15, 2003)
Microjets:
Light-powered
jets (from Physical Review Focus)
The pressure of laser light has been used to create a micrometer-scale
liquid jet at the interface between two liquids of differing
densities. This represents the first example of a stable and
continuous optically-powered microjet. This is significant for
devices that use microjets as well as future applications of
microjets that guide light. (Apr.15, 2003)
Magnetic Levitation: Gold floats in magnetized oxygen (from PhysicsWeb)
Researchers have demonstrated magnetic levitation of various
solid objects including gold, platinum and diamond in oxygen
for the first time. (Apr.10, 2003)
Surface Science: The birth and evolution of surface science: Child
of the union of science and technology (from Proceedings
of the National Academy of Sciences)
A detailed review of the birth and development of the interdisciplinary
field of surface science. (Apr.10, 2003)
Thermolectricity: Go-go
atoms give heat the shake
(from Physical
Review Focus)
Thallium atoms vibrate independently in small cages formed by
antimony atoms in skutterudite (cobalt-antimony compound). These
randomly vibrating "Einstein oscillators" could lead
to better thermoelectric materials. (Apr.7, 2003)
Ferroelectric
Thin Films: Ferroelectric limit (from Nature Materials)
Ferroelectric thin films have great potential for use in dynamic
random access memory chips. Very recent first principles calculations
indicate that BaTiO3 thin films between two metallic SrRuO3 electrodes
in short circuit lose their ferroelectric properties below a
critical thick-ness of about six unit cells. This suggests the
existence of a lower limit for the thickness of useful ferroelectric
layers in electronic devices. (Apr.7, 2003)
Space Shuttle Materials: NASA turns to new designs and materials (from Science News Online)
NASA researchers and engineers are exploring new materials for
the next generation space shuttle, including materials for the
heat resistant tiles and "hot structures" that could
potentially replace the tiles entirely. (Apr.7, 2003)
Lasers:
Supercontinuum
light is red-hot (from AIP
Physics News Update)
Several research groups report developments in the production
of "supercontinuum light," which is multicolored light
with properties similar to that of ordinary laser light, including
a bright, narrow, beam, and coherence, in which the individual
light waves in the beam have a precisely defined interrelationship.
(Mar.31, 2003)
Ceramics:
Watching
bricks age (from AIP Physics News Update)
Ceramics: New dating tricks for bricks (from Nature Materials)
Investigation of the expansion of bricks that date back 1900
years indicates that this expansion due to absorption of moisture
is governed by a power law. This could be used for engineering
brick structures as well as for archeological dating of bricks.
(Mar.31, 2003)
Microfluidics: In the mix
(from Nature
Materials)
The fabrication of three-dimensional (3D) microvascular networks
through direct-write assembly of an organic ink has been demonstrated.
This resulted in a network of smooth cylindrical channels 10300
µm in size, with defined connectivity. Square-spiral towers
are isolated within this vascular network and help promote fluid
mixing through chaotic fluid motion. (Mar.28, 2003)
Nanotechnology: Molecules
stamped into place (from
Nature
Materials)
Microcontact printing has now been shrunk to the nanoscale and
researchers have used it to imprint lines of organic and biological
molecules less than 50 nm wide on silicon substrates. Poly (dimethylsiloxane)
(PDMS) was used for printing the molecular "ink" in
this process titled "nanocontact printing." (Mar.28,
2003)
DNA Conductivity: Electrifying claims for DNA are dashed (from New Scientist)
Research reveals that while DNA molecules can transport electrons
over distances of a few base pairs, they fail to conduct over
longer distances. Any conduction observed over longer lengths
was attributed to a layer of polarized water molecules usually
present. Conductivity over short distances was ascribed to tunneling
effects. (Mar.26, 2003)
Optical Fibers: Spider silk delivers finest optical fibers (from New Scientist)
Extremely fine hollow optical fibers were created by coating
spider silk with a glassy coating and then extracting the silk
by baking. Fibers under 10 nm diameter could be produced by this
method. (Mar.26, 2003)
Transistors: Momentum builds for multiple gate transistors (from IEEE Spectrum)
Multiple-gate transistors are being designed, that operate like
a conventional planar transistor, but because of their 3-D construction,
waste much less power. (Mar.26, 2003)
Nanowires:
Small diameter
silicon nanowire surfaces (from
ChemWeb)
Silicon nanowires of a few to tens of nm diameter were prepared
by an oxide-assisted growth method of SiO. The surface oxide
layer was removed by dipping in hydrofluoric acid, simultaneously
resulting in hydrogen-terminated surfaces. These 1.3 to 7 nm
hydrogen-terminated nanowires were then dispersed on a highly
ordered pyrolytic graphite substrate. (Mar.24, 2003)
Biomaterials: Spiders spring a trap
(from Nature)
Using an atomic force microscope needle to pull liquid spider
silk, researchers have found that the silk appears to contain
soggy molecular nanosprings. This is partially responsible for
some of the remarkable mechanical properties of spider silk.
(Mar. 24, 2003)
Photonic Ink:
Ink changes
colour at flick of a switch
(from Nature)
Researchers have created a photonic ink made from nanospheres
of silicon dioxide along with a fast response metallopolymer
gel to allow for the color of the ink to be tunable. Altering
the applied voltage makes the ink color tunable through the spectrum.
(Mar.24, 2003)
Magnetic Films: Epitaxial BiFeO3 multiferroic thin film heterostructures
(from ChemWeb)
BiFeO3 films of thickness in the range 50500 nm have
been grown by pulsed laser deposition onto single-crystal SrTiO3
substrates. Enhanced electrical and magnetic properties in these
heteroepitaxially constrained thin films have been reported.
(Mar.24, 2003)
Negative Refractive Index: Left handed materials
(from AIP
Physics News Update)
Two groups report new left handed materials with a negative index
of refraction. These materials show left handed behavior when
microwaves were sent into a wedge shaped prism. (Mar. 18, 2003)
Quasicrystals: Catch
a quasiperiodic wave (from
Physical Review
Focus)
In order to simulate electron motion through a quasicrystal,
researchers used a fluid-filled pan with a specially prepared
bottom. Vibrating this creates quasiperiodic standing waves on
the surface. A wave pulse sent through this background sheds
light on the mathematical description of an electron traversing
a quasiperiodic crystal, and shows that it is a Bloch-like wave
pattern. (Mar. 18, 2003)
Terahertz Radiation: T-ray
triumph (from Physical Review Focus)
A synchrotron radiation source has been used to produce a high-quality
coherent beam of far-infrared terahertz radiation. Terahertz
radiation has numerous potential applications including studying
the structure of properties and composition non-destructively.
(Mar. 18, 2003)
Tissue Engineering: Scaffold
delivered through a needle
(from Nature
Materials)
An injectable scaffolding for tissue engineering that self-assembles
in situ into a porous biodegradable matrix has been developed.
The polymer in the form of a slurry of micro- or nanoparticles
of the polymer with seed cells is injected into the body. A crosslinking
agent is then injected to convert this to the matrix. (Mar. 18,
2003)
Quantum Dots: Biological
quantum dots go live (from
PhysicsWeb)
Researchers have developed new biocompatible quantum dots and
have used them to image a live frog embryo using the fluorecence
properties fo the quantum dots. They achieved this by encapsulating
the hydrophobic nanocrystal quantum dots in a hydrophic micelle,
thereby allowing the quantum dots to remain in an aqueous environment
for long periods of time. (Mar.13, 2003)
Optical Microscopy: Optical
microscopy sets new records
(from PhysicsWeb)
Near-field surface enhanced Raman spectrocopy has been used to
image carbon nanotubes. Details of structures under 30 nm were
imaged making this the highest resolution optical images to date.
(Mar.13, 2003)
Hydrogen Isotopes: Hydrogen-7 makes its debut (from PhysicsWeb)
A high-energy beam of Helium-8 atoms was collided with a cryogenic
hydrogen target. This yielded novel hydrogen-7 atoms containing
6 neutrons and 1 proton. (Mar.13, 2003)
Fracture:
Breaking
glass under a microscope
(from Physical
Review Focus)
On the nanoscale, glass is shown to exhibit ductile fracture,
though the mode is brittle fracture on the macroscale. (Mar.10,
2003)
Nanostructures: The shape of things
(From Nature
Physics)
Researchers have found a new method to create indium arsenide
nanorods. They also find that shape is an important parameter
for the properties of these nanostructures, particularly the
diameter-to-length ratio. (Mar.10, 2003)
Nanotechnology: Green plans for tiny tech (from Nature)
Researchers are exploring environmental effects of nanotechnology,
as well as ways to help the environment, such as in efficient
water-purifying systems, or by removing dangerous elements from
industrial waste. (Mar.10, 2003)
Catalysis: Splitting water with a lanthanum-modified catalyst (from Chemistry.org)
Doping the catalyst NaTaO3 with lanthanum improved its catalytic
activity in splitting water ninefold under UV light. (Mar.5,
2003)
Superconductors: Watery
superconductors (from Chemical and
Engineering News)
A type of cobalt oxide superconductor containing intercalated
water has been developed. The material becomes superconducting
at about 5 K. The compound is believed to have the approximate
composition Na0.35CoO2·1.3H2O. (Mar.5, 2003)
Self-Assembly: Shaken, not stirred
(from AIP
Physics News Update)
A new method for encouraging microscopic particles to self assemble
into desired complex patterns has been developed. The technique
is inspired by the patterns formed in shaken mixtures of much
larger granular materials, extending these into microscopic regimes.
The method relies on electrostatic fields to drive metallic microparticles
immersed in liquids. (Mar.3, 2003)
Molecular Electronics: Molecular equivalent of a digital memory bit demonstrated (from
Nature
Materials)
The chemical equivalent of digital memory based on intermolecular
photoinduced proton transfer is demonstrated. (Mar.3, 2003)
Device-on-a-Chip: High-Q harvest
(from Nature
Materials)
Researchers report the development of a toroidal silica microcavity
that can be fabricated directly onto a microchip for use as an
optical microresonator. The microcavity was shown to confine
light with an efficiency of nearly four orders of magnitude greater
than previously demonstrated 'on-chip' resonators. (Mar.3, 2003)
Molecular Electronics: A
molecular switch took only 47 zepto-joules (from AIP Physics News Update)
A molecular switch, consisting of the rotation of one of the
four phenyl legs attached to a complicated porphyrin molecule
from one stable position to another, was found to consume only
47 zepto-joules (47 x 10-21 joules, or 0.3 eV) to operate, roughly10,000
times less than current transistor switches. (Feb.27, 2003)
Molecular Magnets: Nanoporous magnets
(from ChemWeb)
A metalorganic open-framework structure has been created
that shows bulk magnetic ordering at low temperatures. The material,
called MOROF-1, when immersed in liquid ethanol, forms an ordered
honeycomb structure. When removed from the solvent solution,
it becomes an amorphous material. This change is reversible.
(Feb.27, 2003)
Conducting Polymers: New Method of Preparing Conducting Organic Polymer
Films Developed (from ChemWeb)
A new method called Surface Polymerization by Ion-Assisted Deposition
(SPIAD) has been developed for preparing conducting organic thin
films. (Feb.27, 2003)
Dendrimers:
The big and
little squeeze (from Nature
Materials)
Atomic force microscopy has been used to measure the nanoscale
mechanical properties of individual dendrimer (highly branched
polymers) molecules and their aggregates. Using polyester dendrimers
it was demonstrated that the dendrimers get stiffer as the number
of branches increases. (Feb.24, 2003)
Thin Films:
Geometry
and Physics of wrinkling
(from Physical
Review Focus)
A new general theory has been developed that predicts the size,
shape and detailed structure of wrinkles that appear on any thin
film. The theory appears to have the potential to be used in
the manufacture of thin films of any material. (Feb.24, 2003)
Quantum Dots: NanoLights!
Camera! Action! (from Science News
Online)
Quantum dots are being increasingly used in cell biology and
molecular biology as labels for cells and proteins because they
can be made to fluoresce in any color for very long periods of
time. The quantum dots used for biological imaging are nanometer
sized and are typically made of a cadmium selenide core surrounded
by a shell of zinc sulfide. When hit with light, the quantum
dot emits a particular color based on its size. Smaller dots
fluoresce at shorter wavelengths, such as blue, while larger
dots emit longer wavelengths, like red. They are increasing replacing
traditional fluorophores such as dyes and proteins. (Feb.21,
2003)
Biomaterials: Beauty gives diatoms strength (from Nature)
Marine diatoms survive at all depths in freshwater and seawater,
surviving predators as well as enormous pressures. Research now
indicates that this is because of the architecture of their cage-like
armor of silica called frustules. (Feb.21, 2003)
Nanotechnology: Prions
get wired (from Nature)
A version of proteins called prions (thought to cause the "mad
cow" human brain disease) have been found to assemble themselves
into long threads. When coated with silver or gold, these form
extremely thin conducting wires that have enormous potential
for use in nano-devices. (Feb.21, 2003)
Organic LEDs:
Solutions
in colour (From Nature Physics)
A new class of electroluminescent semiconducting polymers has
been developed that, once patterned, become insoluble in the
solvent from which they were deposited. This allows for devices
that require multiple layers such as multi-color light-emitting
elements of a flat-screen display to be fabricated easily. (Feb.21,
2003)
Superconductors: Superconductor
transistor breaks records
(from PhysicsWeb)
A new type of superconducting amplifier, a "Bloch Oscillating
Transistor" consisting of three junctions, has been developed
by Finnish researchers. This has the highest current and power
conduction gains observed in such a device until now. (Feb. 18,
2003)
Nanoscience: Manipulating
nanoparticles (from Physical Review Focus)
Laser light tuned to match an object's internal energy levels
of semiconductor nanoparticles could allow effective optical
trapping of the nanoparticles. This could allow for size- and
shape-selective sorting of nanoparticles to be used as building
blocks for efficient nano-patterned materials. (Feb. 18, 2003)
Conducting Polymers: Conducting made easy
(from ChemWeb)
The solid-state synthesis of highly conducting poly(ethylenedioxythiophene)
is reported. The synthesized polymer is nearly defect-free and
highly ordered. (Feb. 18, 2003)
Nanotubes:
Surfactants
Prevent Agglomeration of Nanotubes in Aqueous Fluids (from ChemWeb)
The tendency of carbon nanotubes to agglomerate in aqueous media
has been a major problem for potential applications. It has now
been discovered that a readily available surfactant, sodium dodecylbenzene
sulfonate (NaDDBS), efficiently disperses nanotubes in water.
(Feb. 18, 2003)
Diamond Electronics: Superficial electronics
(from Nature
Materials)
In-plane gate transistors have been fabricated on diamond surfaces
that have a highly conductive surface layer induced by hydrogen
termination. (Feb. 14, 2003)
Silicon: Polyunsaturated silicon
(from Nature
Materials)
A stable silicon analogue of an allene carbon compound that incorporates
two silicon double bonds has now been synthesized. (Feb. 14,
2003)
Nanoscience:
Salt: The
movie (from AIP Physics News Update)
Researchers have assembled a nano-sized grain of salt, a seven-atom
cluster of 4 cesium atoms and 3 iodide atoms. Using picosecond
pulses of light, they were able to observe how the cluster rearranges
its geometry due to its own internal thermal energy. (Feb. 14,
2003)
Lithography: Ultraviolet lithography
(from AIP
Physics News Update)
Using a beam of synchrotron radiation in the extreme ultraviolet
range for lithography, researchers at the Advanced Light Source
at the Lawrence Berkeley National Lab have produced 70-nm line/space
intervals and isolated lines 39 nm wide. (Feb. 14, 2003)
Photonic Crystals: 3-D photonics
(from Nature
Materials)
A new fabrication method has been developed that makes it possible
to assemble three-dimensional photonic crystal structures at
the microscale. 2-D grid plates are manufactured using standard
lithographic and etching techniques. The plates are then assembled
into a stack using fine mechanical manipulator probes, and aligned
and secured using polystyrene microspheres. (Feb. 10, 2003)
Photovoltaics: Time to dye
(from Nature
Materials)
A new design for photovoltaic cells is reported that uses an
organic dye as its light harvesting layer. This could help reduce
the cost of solar electricity generation. (Feb. 10, 2003)
Nanomolecular Devices: DNA acts like a piston
(from PhysicsWeb)
A DNA nanomolecular device has been conmstructed using an unusual
Quadruplex DNA structure that expands and contracts with the
addition of "fuel" DNA. This could be used as a structural
component in nanomolecular machines. (Feb.5, 2003)
Semiconducting
Polymers: Waterproof electronics (from ChemWeb)
Conducting hybrid inorganic-organic polymers have been developed
that are resistant to environmental degradation even in hot water.
The processing and properties of thin films, fibres and field
effect transistors (FETs) composed of these polymers have been
reported in a recent paper. These materials contain platinum
in their backbone and are based on a salt known as Magnus' green
salt [Pt(NH3)4][PtCl4], first synthesized in the early nineteenth
century. (Feb.5, 2003)
Photonics:
Butterflies
and photonic crystals (from
AIP
Physics News Update)
The colorful iridescence of certain populations of butterflies
is due to the scales on the wings which include arrays of submicron-sized
holes forming natural photonic crystals. The main purpose of
these appears to be thermal management. (Jan.31, 2003)
Diamonds: Bucky
diamonds in the rough (from
Physical Review
Focus)
X-ray absorption spectra results indicate that nanometer-sized
diamonds could have a buckyball-like shape, surrounded by buckyball
caps. This could constitute a new family of carbon cluster molecules.
(Jan.31, 2003)
Low-k Dielectrics: Fast films
(from IEEE Spectrum)
Recent developments in low-k dielectric insulator materials to
replace silicon dioxide. These are critical for coninued improvement
in performance of chips. (Jan.31, 2003)
Quasicrystals: All about quasicrystals
(from ChemWeb)
A broad introduction to quasicrystals including links to online
resources and information. (Jan. 27, 2003)
Mesoporous Materials: Blocked-pore
control (from Nature Materials)
A new study reports the photocontrolled reversible release of
guest molecules from a mesoporous silica (MCM-41) that has coumarin
ligands attached to the outer pore entrances. This is akin to
having molecular 'double doors' that can be opened and closed
with light, thereby allowing for controlled release of absorbed
chemicals from within the pores. (Jan. 27, 2003)
Photonic Crystals: Nanotubes
send light from pillar to post
(from Nature
Materials)
A new self-assembly technique shows a possible route for creating
photonic crystals for visible wavelengths. The material is comprised
of a honeycomb pattern of carbon nanotubes grown from a patterned
array of catalytic nickel nanoparticles. Periodic nanodots of
nickel were deposited in the interstices of a two-dimensional
colloidal crystal of an array of nanoscale polystyrene spheres
that spontaneously formed a hexagonally close-packed monolayer
on a silicon substrate. The whole process is non-lithogragraphic.
(Jan. 27, 2003)
Carbon Nanotubes: Nanotube
hydroelectricity (from Nature
Materials)
Carbon nanotubes have been shown to have great potential for
making passive electronic components such as transistor switches
and sensors. A new study now shows that nanotubes might also
be used to generate an electrical signal when immersed in a flowing
liquid. The study experimentally demonstrated that flow of a
liquid on single-walled carbon nanotube bundles induces a voltage/current
in the sample along the direction of the flow. Nanotubes could
thus be used as sensitive flow sensors as well as for energy
conversion. (Jan. 27, 2003)
DNA: Portrait of a molecule
(from Nature)
The mysteries of the DNA molecule and its physical existence
in a cell. (Jan. 27, 2003)
Defect Diffusion: New
oxygen surface diffusion mechanism
(from Chemical
and Engineering News)
A rapid and high-resolution scanning tunneling microscopy (STM)
method has been used to study diffusion of oxygen vacancies on
a TiO2 crystal surface in the presence of gaseous oxygen. Oxygen
vacancies were found to diffuse across the surface along specific
crystal directions. This was accomplished by adsorbed oxygen
on the surface interacting with an oxygen vacancy, thereby creating
a vacancy elsewhere on the surface. (Jan. 25, 2003)
Large Area Electronics: Hot off the press
(From Nature
Physics)
Thermal imaging, a nonlithographic technique, which enables printing
multiple, successive layers via a dry additive process, was used
along with tailored printable conductors for fabricating organic
electronic devices. This method is capable of patterning a range
of organic materials at high speed over large areas with micron
size resolution and good electrical performance. This technique
was used to print a functioning, 4000 cm2 area active matrix
backplane display circuit containing several thousand transistors.
(Jan. 25, 2003)
Microlenses: Liquid lensing
(From Nature
Physics)
A liquid microdroplet was used as a microlens in a recent study,
wherein the focus and position could be electronically tuned.
The microlens consisted of a droplet of a transparent conductive
liquid placed on a dielectric substrate with a low surface energy
coating. (Jan. 25, 2003)
Magnetization: Swifter
switching (from Physical Review Focus)
Two recent papers describe applying an ultrafast magnetic field
pulse to reverse micromagnets, thereby flipping micron-sized
magnets as quickly as their fundamental speed limit will allow.
This involves applying the field horizontally to create precessional
motion in the vertical direction for flipping the micromagnet,
which is the most efficient method to do so. (Jan. 21, 2003)
Spectrometry: Inside the engine
(from ChemWeb)
A new mass spectrometer to analyze emissions continuously and
in real time from diesel engines has been developed. It uses
32-micron silica capillaries, mounted at atmospheric pressure
in the intakes, and in a vacuum at the outlet. This has been
used to optimize performance of diesel engines to minimize harmful
emissions. (Jan. 21, 2003)
Lasers:
Slimline
lasers could bring light onto chips
(from Nature
Materials)
Nanowire lasers of 100 nm thickness made from individual semiconducting
wires have been developed by researchers. Electronic control
of these have been demonstrated. The CdS nanowires were deposited
on a silicon substrate. The nanowires act as n-type semiconductors
while the silicon is doped so that it is p-type and the interface
of the two forms a p-n junction, across which charge can be injected
into the nanowire wherein recombination of charge carriers causes
emission of blue-green light. (Jan. 21, 2003)
Liquid Crystals: The layered look
(from ChemWeb)
A novel liquid crystalline compound with a mesophase consisting
of a 2-D lattice is reported. The study demonstrates that the
use of appropriately designed simple low-molecular weight molecules
can lead to complex self-organized systems. (Jan. 21, 2003)
Granular Materials: Nut theory gets a shakedown (from Nature)
Size segregation of a mixture of different sized pieces by shaking
depends on the shaking frequency and amplitude, and the overall
height, based on the competition between percolation and condensation
(Jan. 15, 2003)
Nanotubes: Add ceramic fracture protection to list of nanotube
attributes (from Smalltimes)
Adding carbon nanotubes to a ceramic was found to significantly
increase toughness. Adding 10% nanotubes by volume to an alumina
ceramic nearly tripled its toughness. (Jan.15, 2003)
Nanomaterials: Polymer-coated nanocrystals (from ChemWeb)
The preparation of semiconductor nanocrystals with versatile
multifunctional polymer ligands is reported. (Jan. 14, 2003)
Crystallization: The crystal engineer
(from ChemWeb)
A new study reports the in situ co-crystallization of
a series of low-melting co-crystals of pyrazine and n-alkyl
carboxylic acids. This is useful for the synthesis and characterization
of low-melting multi-component crystal systems. (Jan. 14, 2003)
Nanoelectronics: Microelectronics
goes nanomechanical (from
PhysicsWeb)
A step towards- the first nanomechanically assisted single-electron
transistor has been taken with the developmente of a new type
of device in which electron transport is manipulated by both
electrical and mechanical means. (Jan. 14, 2003)
Nanotechnology: Nanotechnology
is good for the heart (from
PhysicsWeb)
A device consisting of an array of sub-millimetre sized cantilevers
to monitor blood proteins has been built. It can measure proteins
whose concentration reflects the state of a person's heart for
quicker and easier diagnoses of heart attacks than existing technologies,
which rely on the radioactive labelling of proteins. The array
consists of eight cantilevers, all 0.5 mm long, 0.1 mm wide and
500 nm thick, and coated on their upper surfaces with blood protein
antibodies. When immersed in a liquid containing blood proteins,
the antibodies bind to the proteins and induce a stress in the
cantilevers, causing them to bend. (Jan. 14, 2003)
Liquid Crystals: Liquid crystals show superficial influence (from Nature Materials)
Different phase transitions were observed experimentally for
the first time for nematic liquid crystals close to the surface
and in the bulk. This has important implications since most technological
applications such as LCDs have liquid crystals near a surface.
Also, near the surface, abrupt (first order) or gradual (continuous)
wetting transitions were observed depending upon the nature of
the surface. (Jan. 9, 2003)
Nanoscale Superfluidity: Nanoscale superfluidity confirmed (From Nature Physics)
Theoretical calculations show that hydrogen can become a superfluid
on the nanoscale. A superfluid, a peculiar and counterintuitive
material, has no viscosity allowing an object to move in it without
friction. A layer of molecular hydrogen surrounding and solvating
a small molecule was found to display the characteristics of
a superfluid at temperatures below about 0.3 K. (Jan. 9, 2003)
[Also see Liquid hydrogen turns superfluid from PhysicsWeb]
Carbon Nanotubes: Tuning carbon nanotube resonance frequencies (from AIP Physics News Update)
Electric field pulling was used to tune carbon nanotube resonance
frequencies. The field pulling was achieved by varying a static
voltage applied between the nanotubes and a counter electrode.
(Jan. 3, 2003)
Tissue Engineering: Living tissue made to order (from Nature)
(2002 MRS Fall Meeting News)
A laser based firing mechanism was used to shoot cells onto nutrient
rich polymer gel strips and make them grow. This technique could
be used in future to close surgical incisions rather than use
stitches or staples. (Jan. 3, 2003)
Self Assembly: Chemical attraction solves geometric puzzles (from Nature)
Aggregates that formed a particular shaped spontaneously reconfigured
themselves to a different shape by a change in the environment.
Adding a salt to a liquid with floating aggregates of kite-shaped
plates that formed hexagons caused the aggregates to reconfigure
to yield equilateral triangles. (Jan. 3, 2003)
Water-Metal Interaction: Water structure down flat (from Physical
Review Focus)
A new study reveals the bonding pattern of water on a metal surface
for the first time. A layer of deuterium enriched water was placed
on a Pt (111) surface. X-ray absorption spectra indicate that
the layer was essentially flat with every water molecule sticking
to the Pt surface. (Jan. 3, 2003)
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