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Kosmos
Astronomia Astrofizyka
Inne

Kultura
Sztuka dawna i współczesna, muzea i kolekcje

Metoda
Metodologia nauk, Matematyka, Filozofia, Miary i wagi, Pomiary

Materia
Substancje, reakcje, energia
Fizyka, chemia i inżynieria materiałowa

Człowiek
Antropologia kulturowa Socjologia Psychologia Zdrowie i medycyna

Wizje
Przewidywania Kosmologia Religie Ideologia Polityka

Ziemia
Geologia, geofizyka, geochemia, środowisko przyrodnicze

Życie
Biologia, biologia molekularna i genetyka

Cyberprzestrzeń
Technologia cyberprzestrzeni, cyberkultura, media i komunikacja

Działalność
Wiadomości | Gospodarka, biznes, zarządzanie, ekonomia

Technologie
Budownictwo, energetyka, transport, wytwarzanie, technologie informacyjne

Kolekcje IOP - REVIEWS

Reviews

Carbon nanotubes have the potential to spur future development in electronics due to their
unequalled electrical properties. In this article, we present a review on carbon nanotube-based
circuits in terms of their electrical performance in two major directions: nanoelectronics and
macroelectronics. In the nanoelectronics direction, we direct our discussion to the performance of
aligned carbon nanotubes for digital circuits and circuits designed for radio-frequency
applications. In the macroelectronics direction, we focus our attention on the performance of thin
films of carbon nanotube random networks in digital circuits, display applications, and printed
electronics. In the last part, we discuss the existing challenges and future directions of
nanotube-based nano- and microelectronics.

http://iopscience.iop.org/0268-1242/29/7/073001 2014/05/02 - 20:40

Viscosity is an important rheological property of metals in casting because it controls the rate of
transport of liquid metals, which may lead to casting defects such as hot tearing and porosity. The
measurement methods and numerical models of the viscosity of liquid and semi-solid state metals that
have been published to date are reviewed in this paper. Most experimental measurements have been
performed with rotational and oscillatory viscometers, which offer advantages at low viscosities in
particular. Besides these two traditional methods for measuring viscosities, a couple of studies
also introduced the technique of isothermal compression for alloys in the semi-solid state, and even
an optical basicity method for the viscosity of slags. As to numerical models, most published
results show that the viscosity of liquid and semi-solid state metals can be described by the
Arrhenius, Andrade, Kaptay or Budai–Bemkő–Kaptay equations. In addition, there are some alternative
models, su...

http://iopscience.iop.org/0957-0233/25/6/062001 2014/04/25 - 22:33

We review the present understanding of the behavior of ions at the air–water and oil–water
interfaces. We argue that while the alkali metal cations remain strongly hydrated and are repelled
from the hydrophobic surfaces, the anions must be classified into kosmotropes and chaotropes. The
kosmotropes remain strongly hydrated in the vicinity of a hydrophobic surface, while the chaotropes
lose their hydration shell and can become adsorbed to the interface. The mechanism of adsorption is
still a subject of debate. Here, we argue that there are two driving forces for anionic adsorption:
the hydrophobic cavitational energy and the interfacial electrostatic surface potential of water.
While the cavitational contribution to ionic adsorption is now well accepted, the role of the
electrostatic surface potential is much less clear. The difficulty is that even the sign of this
potential is a subject of debate, with the ab initio and the classical force field simulations
predicting elec...

http://iopscience.iop.org/0953-8984/26/20/203101 2014/04/25 - 22:33

The development of interatomic potentials employing artificial neural networks has seen tremendous
progress in recent years. While until recently the applicability of neural network potentials (NNPs)
has been restricted to low-dimensional systems, this limitation has now been overcome and
high-dimensional NNPs can be used in large-scale molecular dynamics simulations of thousands of
atoms. NNPs are constructed by adjusting a set of parameters using data from electronic structure
calculations, and in many cases energies and forces can be obtained with very high accuracy.
Therefore, NNP-based simulation results are often very close to those gained by a direct application
of first-principles methods. In this review, the basic methodology of high-dimensional NNPs will be
presented with a special focus on the scope and the remaining limitations of this approach. The
development of NNPs requires substantial computational effort as typically thousands of reference
calculations are requi...

http://iopscience.iop.org/0953-8984/26/18/183001 2014/04/23 - 19:38

The re-creation of the tumor microenvironment including tumor–stromal interactions, cell–cell
adhesion and cellular signaling is essential in cancer-related studies. Traditional two-dimensional
(2D) cell culture and animal models have been proven to be valid in some areas of explaining
cancerous cell behavior and interpreting hypotheses of possible mechanisms. However, a well-defined
three-dimensional (3D) in vitro cancer model, which mimics tumor structures found in vivo and allows
cell–cell and cell–matrix interactions, has gained strong interest for a wide variety of diagnostic
and therapeutic applications. This communication attempts to provide a representative overview of
applying 3D in vitro biological model systems for cancer related studies. The review compares and
comments on the differences in using 2D models, animal models and 3D in vitro models for cancer
research. Recent technologies to construct and develop 3D in vitro cancer model...

http://iopscience.iop.org/1758-5090/6/2/022001 2014/04/18 - 22:46

This tutorial presents the theory necessary to model the propagation of light through an atomic
vapour. The history of atom–light interaction theories is reviewed, and examples of resulting
applications are provided. A numerical model is developed and results presented. Analytic solutions
to the theory are found, based on approximations to the numerical work. These solutions are found to
be in excellent agreement with experimental measurements.

http://iopscience.iop.org/0953-4075/47/9/093001 2014/04/18 - 22:46

Choosing a suitable site for a nuclear power station requires the consideration and balancing of
several factors. Some ‘physical’ site characteristics, such as the local climate and the potential
for seismic activity, will be generic to all reactors designs, while others, such as the
availability of cooling water, the area of land required and geological conditions capable of
sustaining the weight of the reactor and other buildings will to an extent be dependent on the
particular design of reactor chosen (or alternatively the reactor design chosen may to an extent be
dependent on the characteristics of an available site). However, one particularly interesting
tension is a human and demographic one. On the one hand it is beneficial to place nuclear stations
close to centres of population, to reduce transmission losses and other costs (including to the
local environment) of transporting electricity over large distances from generator to consumer. On
the other it is advantageous to ...

http://iopscience.iop.org/0952-4746/34/2/R1 2014/04/14 - 10:21

The United States radiation medical countermeasures (MCM) programme for radiological and nuclear
incidents has been focusing on developing mitigators for the acute radiation syndrome (ARS) and
delayed effects of acute radiation exposure (DEARE), and biodosimetry technologies to provide
radiation dose assessments for guiding treatment. Because a nuclear accident or terrorist incident
could potentially expose a large number of people to low to moderate doses of ionising radiation,
and thus increase their excess lifetime cancer risk, there is an interest in developing mitigators
for this purpose. This article discusses the current status, issues, and challenges regarding
development of mitigators against radiation-induced cancers. The challenges of developing mitigators
for ARS include: the long latency between exposure and cancer manifestation, limitations of animal
models, potential side effects of the mitigator itself, potential need for long-term use, the
complexity of human tr...

http://iopscience.iop.org/0952-4746/34/2/R25 2014/04/14 - 10:21

Shape memory alloys (SMAs) are a unique class of metallic materials with the ability to recover
their original shape at certain characteristic temperatures (shape memory effect), even under high
applied loads and large inelastic deformations, or to undergo large strains without plastic
deformation or failure (super-elasticity). In this review, we describe the main features of SMAs,
their constitutive models and their properties. We also review the fatigue behavior of SMAs and some
methods adopted to remove or reduce its undesirable effects. SMAs have been used in a wide variety
of applications in different fields. In this review, we focus on the use of shape memory alloys in
the context of morphing aircraft, with particular emphasis on variable twist and camber, and also on
actuation bandwidth and reduction of power consumption. These applications prove particularly
challenging because novel configurations are adopted to maximize integration and effectiveness of
SMAs, which play ...

http://iopscience.iop.org/0964-1726/23/6/063001 2014/04/11 - 13:20

Droplet epitaxy was proposed to fabricate quantum dots in the early 1990s. Even though many research
efforts have been devoted to droplet epitaxy since then, it is only until recently that droplet
epitaxy has received worldwide attention. Compared with the well-known Stranski–Krastanow (S–K)
growth mode, droplet epitaxy consists of the formation and crystallization of droplets, which
enables fabrication of three-dimensional nanostructures in both lattice-mismatched and
lattice-matched material systems. The flexibility of the droplet epitaxy growth method has brought
to light the great potential of droplet epitaxy in optoelectronic applications. However, most works
on droplet epitaxy focus on fabrication, optical properties and understanding the growth mechanisms
of various nanostructures. In terms of device applications, droplet epitaxy has fallen behind
conventional nanostructure self-assembly using the S–K mode. One of the major reasons is the
relative low optical quality of th...

http://iopscience.iop.org/0022-3727/47/17/173001 2014/04/11 - 13:20

Diffusion is the driver of critical biological processes in cellular and molecular biology. The
diverse temporal scales of cellular function are determined by vastly diverse spatial scales in most
biophysical processes. The latter are due, among others, to small binding sites inside or on the
cell membrane or to narrow passages between large cellular compartments. The great disparity in
scales is at the root of the difficulty in quantifying cell function from molecular dynamics and
from simulations. The coarse-grained time scale of cellular function is determined from molecular
diffusion by the mean first passage time of molecular Brownian motion to a small targets or through
narrow passages. The narrow escape theory (NET) concerns this issue. The NET is ubiquitous in
molecular and cellular biology and is manifested, among others, in chemical reactions, in the
calculation of the effective diffusion coefficient of receptors diffusing on a neuronal cell
membrane strewn with obstacl...

http://iopscience.iop.org/1751-8121/47/17/173001 2014/04/09 - 17:48

Silicon quantum dots (SiQDs) hold great promise for many future technologies. Silicon is already at
the core of photovoltaics and microelectronics, and SiQDs are capable of efficient light emission
and amplification. This is crucial for the development of the next technological frontiers—silicon
photonics and optoelectronics. Unlike any other quantum dots (QDs), SiQDs are made of non-toxic and
abundant material, offering one of the spectrally broadest emission tunabilities accessible with
semiconductor QDs and allowing for tailored radiative rates over many orders of magnitude. This
extraordinary flexibility of optical properties is achieved via a combination of the spatial
confinement of carriers and the strong influence of surface chemistry. The complex physics of this
material, which is still being unraveled, leads to new effects, opening up new opportunities for
applications. In this review we summarize the latest progress in this fascinating research field,
with special atte...

http://iopscience.iop.org/0953-8984/26/17/173201 2014/04/09 - 17:48

This paper provides a review of recent developments in the rapidly changing and advancing field of
smart fabric sensor and electronic textile technologies. It summarizes the basic principles and
approaches employed when building fabric sensors as well as the most commonly used materials and
techniques used in electronic textiles. This paper shows that sensing functionality can be created
by intrinsic and extrinsic modifications to textile substrates depending on the level of integration
into the fabric platform. The current work demonstrates that fabric sensors can be tailored to
measure force, pressure, chemicals, humidity and temperature variations. Materials, connectors,
fabric circuits, interconnects, encapsulation and fabrication methods associated with fabric
technologies prove to be customizable and versatile but less robust than their conventional
electronics counterparts. The findings of this survey suggest that a complete smart fabric system is
possible through the inte...

http://iopscience.iop.org/0964-1726/23/5/053001 2014/04/04 - 19:27

The fundamental building block of quantum information processing technologies is the quantum-bit a
‘qubit.’ These technologies require the ability to prepare, control, and read out a qubit state.
Spins confined in self-assembled quantum dots are promising candidates for a quantum bit, because
semiconductors are compatible with mature modern opto- and micro-electronics. These quantum dot
systems offer two more advantages: they are excellent interfaces between the spin state—an anchored
qubit and a photon—a ‘flying qubit’ and they provide means to coherently control the spin qubit by
ultrashort optical pulses. In this review, we thoroughly discuss the qubit provided by an
optically-excited electron in a quantum dot–the exciton qubit. We demonstrate its spin state
initialization, coherent control and read-out using ultrashort optical pulses.

http://iopscience.iop.org/0268-1242/29/5/053001 2014/03/28 - 14:33

Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer
cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum
standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the
construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface
science and thin films include new phenomena observed in electron transport near solid surfaces as
well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and
thin-film characterization have been applied in the conservation technology of cultural heritage
objects and recent advances in the characterization of biointerfaces are presented. The combination
of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena
of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at
solid–liquid interfac...

http://iopscience.iop.org/0022-3727/47/15/153001 2014/03/28 - 14:33

The fate of matter when decreasing the temperature at constant pressure is that of passing from gas
to liquid and, subsequently, from liquid to crystal. However, a class of materials can exist in an
amorphous phase below the melting temperature. On cooling such materials, a glass is formed; that
is, a material with the rigidity of a solid but exhibiting no long-range order. The study of the
thermodynamics and dynamics of glass-forming systems is the subject of continuous research. Within
the wide variety of glass formers, an important sub-class is represented by glass forming polymers.
The presence of chain connectivity and, in some cases, conformational disorder are unfavourable
factors from the point of view of crystallization. Furthermore, many of them, such as amorphous
thermoplastics, thermosets and rubbers, are widely employed in many applications. In this review,
the peculiarities of the thermodynamics and dynamics of glass-forming polymers are discussed, with
particular e...

http://iopscience.iop.org/0953-8984/26/15/153101 2014/03/28 - 14:33

Nature has adapted different methods for surviving dry, arid, xeric conditions. It is the focus of
this comparative review to pull together the relevant information gleaned from the literature that
could be utilized to design moisture harvesting devices informed by biomimetics. Most water
harvesting devices in current use are not informed by nature and those that do are usually based on
a biomimetic principle that has been based on one species only. This review draws on the published
literature to establish a list of species (animals (vertebrates/invertebrates) and plants) whose
habitat is in mainly dry or arid regions and that are known to harvest airborne moisture. Key
findings have been outlined and review comments and discussion set out. Following this, surface
feature convergences have been identified, namely hexagonal microstructures, groove-like and
cone-like geometries. This has been coupled with direction of water flow that is driven by surface
energy. As far as the auth...

http://iopscience.iop.org/1748-3190/9/3/031002 2014/03/21 - 22:30

The quest for the origin of matter in the Universe had been the subject of philosophical and
theological debates over the history of mankind, but quantitative answers could be found only by the
scientific achievements of the last century. A first important step on this way was the development
of spectral analysis by Kirchhoff and Bunsen in the middle of the 19th century, which provided first
insight in the chemical composition of the sun and the stars. The energy source of the stars and the
related processes of nucleosynthesis, however, could be revealed only with the discoveries of
nuclear physics. A final break-through came eventually with the compilation of elemental and
isotopic abundances in the solar system, which reflect the various nucleosynthetic processes in
detail. This review focuses on the mass region above iron, where the formation of the elements is
dominated by neutron capture, mainly in the slow ( s ) and rapid ( r ) processes. Following a brief
histori...

http://iopscience.iop.org/0954-3899/41/5/053101 2014/03/21 - 22:30

Fluorescent semiconductor nanocrystals (or quantum dots) are very promising agents for bioimaging
applications because their optical properties are superior compared to those of conventional organic
dyes. However, not all the properties of these quantum dots suit the stringent criteria of in vivo
applications, i.e. their employment in living organisms that might be of importance in therapy and
medicine. In our review, we first summarize the properties of an ‘ideal’ biomarker needed for in
vivo applications. Despite recent efforts, no such hand-made fluorescent quantum dot exists that may
be considered as ‘ideal’ in this respect. We propose that ab initio atomistic simulations with
predictive power can be used to design ‘ideal’ in vivo fluorescent semiconductor nanoparticles. We
briefly review such ab initio methods that can be applied to calculate the electronic and optical
properties of very small nanocrystals, with extra emphasis on density fu...

http://iopscience.iop.org/0953-8984/26/14/143202 2014/03/21 - 22:30

The response of oxide thin films to polar discontinuities at interfaces and surfaces has generated
enormous activity due to the variety of interesting effects that it gives rise to. A case in point
is the discovery of the electron gas at the interface between LaAlO 3 and SrTiO 3 , which has since
been shown to be quasi-two-dimensional, switchable, magnetic and/or superconducting. Despite these
findings, the origin of the two-dimensional electron gas is highly debated and several possible
mechanisms remain. Here we review the main proposed mechanisms and attempt to model expected effects
in a quantitative way with the ambition of better constraining what effects can/cannot explain the
observed phenomenology. We do it in the framework of a phenomenological model constructed to provide
an understanding of the electronic and/or redox screening of the chemical charge in oxide
heterostructures. We also discuss the effect of intermixing, both conserving and not conser...

http://iopscience.iop.org/0953-8984/26/14/143201 2014/03/19 - 00:51

With the rapid development of on-chip optical interconnects and optical computing in the past
decade, silicon-based integrated devices for monolithic and hybrid optoelectronic integration have
attracted wide attention. Due to its narrow pseudo-direct gap behavior and compatibility with Si
technology, epitaxial Ge-on-Si has become a significant material for optoelectronic device
applications. In this paper, we describe recent research progress on heteroepitaxy of Ge flat films
and self-assembled Ge quantum dots on Si. For film growth, methods of strain modification and
lattice mismatch relief are summarized, while for dot growth, key process parameters and their
effects on the dot density, dot morphology and dot position are reviewed. The results indicate that
epitaxial Ge-on-Si materials will play a bigger role in silicon photonics.

http://iopscience.iop.org/1468-6996/15/2/024601 2014/03/19 - 00:51

Current Micro Aerial Vehicles (MAVs) are greatly limited by being able to operate in air only.
Designing multimodal MAVs that can fly effectively, dive into the water and retake flight would
enable applications of distributed water quality monitoring, search and rescue operations and
underwater exploration. While some can land on water, no technologies are available that allow them
to both dive and fly, due to dramatic design trade-offs that have to be solved for movement in both
air and water and due to the absence of high-power propulsion systems that would allow a transition
from underwater to air. In nature, several animals have evolved design solutions that enable them to
successfully transition between water and air, and move in both media. Examples include flying fish,
flying squid, diving birds and diving insects. In this paper, we review the biological literature on
these multimodal animals and abstract their underlying design principles in the perspective of
building a ...

http://iopscience.iop.org/1748-3190/9/3/031001 2014/03/12 - 13:06

Metal organic framework (MOF) materials have attracted a lot of attention due to their numerous
applications in fields such as hydrogen storage, carbon capture and gas sequestration. In all these
applications, van der Waals forces dominate the interaction between the small guest molecules and
the walls of the MOFs. In this review article, we describe how a combined theoretical and
experimental approach can successfully be used to study those weak interactions and elucidate the
adsorption mechanisms important for various applications. On the theory side, we show that, while
standard density functional theory is not capable of correctly describing van der Waals
interactions, functionals especially designed to include van der Waals forces exist, yielding
results in remarkable agreement with experiment. From the experimental point of view, we show
examples in which IR adsorption and Raman spectroscopy are essential to study molecule/MOF
interactions. Importantly, we emphasize through...

http://iopscience.iop.org/0953-8984/26/13/133002 2014/03/12 - 13:06

Poloidal and toroidal rotation has been recognized to play an important role in heat transport and
magnetohydrodynamic (MHD) stability in tokamaks and helical systems. It is well known that theE × B
shear due to poloidal and toroidal flow suppresses turbulence in the plasma and contributes to the
improvement of heat and particle transport, while toroidal rotation helps one to stabilize MHD
instabilities such as resistive wall modes and neoclassical tearing mode. Therefore, understanding
the role of momentum transport in determining plasma rotation is crucial in toroidal discharges,
both in tokamaks and helical systems. In this review paper, the driving and damping mechanisms of
poloidal and toroidal rotation are outlined. Driving torque due to neutral beam injection and
radio-frequency waves, and damping due to parallel viscosity and neoclassical toroidal viscosity
(NTV) are described. Regarding momentum transport, the radial flux of momentum has diffusive and
non-...

http://iopscience.iop.org/0029-5515/54/4/045001 2014/03/12 - 13:06

Focusing and guiding light into semiconductor nano-structures can deliver revolutionary concepts for
photonic devices, which offer a practical pathway towards next-generation power-efficient optical
networks. In this review, we consider the prospects for photonic switches using semiconductor
quantum dots (QDs) and photonic cavities which possess unique properties based on their low
dimensionality. The optical nonlinearity of such photonic switches is theoretically analysed by
introducing the concept of a field enhancement factor. This approach reveals a drastic improvement
in both power-density and speed, which is able to overcome the limitations that have beset
conventional photonic switches for decades. In addition, the overall power consumption is reduced
due to the atom-like nature of QDs, as well as the nano-scale footprint of photonic cavities. Based
on this theoretical perspective, the current state-of-the-art QD/cavity switches are reviewed in
terms of various optical non...

http://iopscience.iop.org/0022-3727/47/13/133001 2014/03/10 - 20:47

Processing of group III-nitride materials such as AlN in the form of photonic crystals or microdiscs
opens new perspectives for basic cavity quantum electrodynamic studies or the development of novel
devices operating in the ultra-violet range. These devices can be either passive or active by
embedding self-assembled GaN quantum dots. We review the recent progress achieved in the field of
nitride-based microresonators for UV nanophotonics.

http://iopscience.iop.org/2043-6262/5/2/023001 2014/03/07 - 16:36

We have recently developed a method to calculate thermodynamic properties of macroscopic systems by
extrapolating properties of systems of molecular dimensions. Appropriate scaling laws for small
systems were derived using the method for small systems thermodynamics of Hill, considering surface
and nook energies in small systems of varying sizes. Given certain conditions, Hill's method
provides the same systematic basis for small systems as conventional thermodynamics does for large
systems. We show how the method can be used to compute thermodynamic data for the macroscopic limit
from knowledge of fluctuations in the small system. The rapid and precise method offers an
alternative to current more difficult computations of thermodynamic factors from Kirkwood–Buff
integrals. When multiplied with computed Maxwell–Stefan diffusivities, agreement is found between
computed predictions and experiments of the Fick diffusion coefficients for several binary systems.
Diffusion coefficients...

http://iopscience.iop.org/2043-6262/5/2/023002 2014/03/07 - 16:36

Atomic scale nanowires attract enormous interest in a wide range of fields. On the one hand, due to
their quasi-one-dimensional nature, they can act as an experimental testbed for exotic physics:
Peierls instability, charge density waves, and Luttinger liquid behavior. On the other hand, due to
their small size, they are of interest not only for future device applications in the
micro-electronics industry, but also for applications regarding molecular electronics. This
versatile nature makes them interesting systems to produce and study, but their size and growth
conditions push both experimental production and theoretical modeling to their limits. In this
review, modeling of atomic scale nanowires on semiconductor surfaces is discussed, focusing on the
interplay between theory and experiment. The current state of modeling efforts on Pt- and Au-induced
nanowires on Ge(001) is presented, indicating their similarities and differences. Recently
discovered nanowire systems (Ir, Co, S...

http://iopscience.iop.org/0953-8984/26/13/133001 2014/03/07 - 16:36

We describe a general N -solitonic solution of the focusing nonlinear Schrödinger equation in the
presence of a condensate by using the dressing method. We give the explicit form of one- and
two-solitonic solutions and study them in detail as well as solitonic atoms and degenerate
solutions. We distinguish a special class of solutions that we call regular solitonic solutions.
Regular solitonic solutions do not disturb phases of the condensate at infinity by coordinate. All
of them can be treated as localized perturbations of the condensate. We find a broad class of
superregular solitonic solutions which are small perturbations at a certain moment of time.
Superregular solitonic solutions are generated by pairs of poles located on opposite sides of the
cut. They describe the nonlinear stage of the modulation instability of the condensate and play an
important role in the theory of freak waves.

http://iopscience.iop.org/0951-7715/27/4/R1 2014/03/07 - 16:36

The evolution of silicon cryoetching is reported in this topical review, from its very first
introduction by a Japanese team to today's advanced technologies. The main advances in terms of the
performance and comprehension of the mechanisms are chronologically presented. After presenting the
principle of silicon cryoetching, the main defects encountered in cryoetching (such as undercut,
bowing and crystal orientation dependent etching) are presented and discussed. Mechanisms involved
in SiO x F y passivation layer growth in standard cryoetching are investigated through several in
situ characterization experiments. The STiGer process and alternative cryoetching processes for
high-aspect-ratio structures are also proposed to enhance the process robustness. The
over-passivation regime, which can provide self-organized columnar microstructures, is presented and
discussed. Finally, advanced technologies, such as the cryoetching of sub-20 nm feat...

http://iopscience.iop.org/0022-3727/47/12/123001 2014/03/07 - 16:36

Research efforts addressing spin waves (magnons) in micro- and nanostructured ferromagnetic
materials have increased tremendously in recent years. Corresponding experimental and theoretical
work in magnonics faces significant challenges in that spin-wave dispersion relations are highly
anisotropic and different magnetic states might be realized via, for example, the magnetic field
history. At the same time, these features offer novel opportunities for wave control in solids going
beyond photonics and plasmonics. In this topical review we address materials with a periodic
modulation of magnetic parameters that give rise to artificially tailored band structures and allow
unprecedented control of spin waves. In particular, we discuss recent achievements and perspectives
of reconfigurable magnonic devices for which band structures can be reprogrammed during operation.
Such characteristics might be useful for multifunctional microwave and logic devices operating over
a broad frequency...

http://iopscience.iop.org/0953-8984/26/12/123202 2014/03/07 - 16:36

This topical review provides an up-to-date overview of the theoretical and practical aspects of
therapeutic kilovoltage x-ray beam dosimetry. Kilovoltage x-ray beams have the property that the
maximum dose occurs very close to the surface and thus, they are predominantly used in the treatment
of skin cancers but also have applications for the treatment of other cancers. In addition,
kilovoltage x-ray beams are used in intra operative units, within animal irradiators and in on-board
imagers on linear accelerators and kilovoltage dosimetry is important in these applications as well.
This review covers both reference and relative dosimetry of kilovoltage x-ray beams and provides
recommendations for clinical measurements based on the literature to date. In particular, practical
aspects for the selection of dosimeter and phantom material are reviewed to provide suitable advice
for medical physicists. An overview is also presented of dosimeters other than ionization chambers
which can ...

http://iopscience.iop.org/0031-9155/59/6/R183 2014/03/01 - 20:17

Due to the unique set of properties possessed by ZnO, thin films of ZnO have received more and more
interest in the last 20 years as a potential material for applications such as thin-film
transistors, light-emitting diodes and gas sensors. At the same time, the increasingly stringent
requirements of the microelectronics industry, among other factors, have led to a dramatic increase
in the use of atomic layer deposition (ALD) technique in various thin-film applications. During this
time, the research on ALD-grown ZnO thin films has developed from relatively simple deposition
studies to the fabrication of increasingly intricate nanostructures and an understanding of the
factors affecting the fundamental properties of the films. In this review, we give an overview of
the current state of ZnO ALD research including the applications that are being considered for ZnO
thin films.

http://iopscience.iop.org/0268-1242/29/4/043001 2014/02/27 - 01:24

A spin current, a flow of electron spins in a solid, interacts with magnetization by exchanging the
spin angular momentum. This interaction is responsible for spintronic functionalities; spin
injection into a ferromagnet transfers the spin angular momentum, enabling switching the direction
of the magnetization or driving magnetization precession. The inverse of this process, i.e., the
angular momentum transfer from magnetization to carrier spins, is spin pumping; a spin current is
emitted from a ferromagnet by the angular momentum transfer from precessing magnetization to carrier
spins through dynamical spin–exchange coupling at a ferromagnetic/nonmagnetic interface. This
dynamical spin injection offers a versatile route for generating spin currents in a wide range of
materials, providing a pathway to explore spin physics in condensed matter.

http://iopscience.iop.org/0268-1242/29/4/043002 2014/02/27 - 01:24

Nanochannels remain at the focus of growing scientific and technological interest. The nanometer
scale of the structure allows the discovery of a new range of phenomena that has not been possible
in traditional microchannels, among which a direct field effect control over the charges in
nanochannels is very attractive for various applications, since it offers a unique opportunity to
integrate wet ionics with dry electronics seamlessly. This review will focus on the voltage gated
ionic and molecular transport in engineered gated nanochannels. We will present an overview of the
transport theory. Fabrication techniques regarding the gated nanostructures will also be discussed.
In addition, various applications using the voltage gated nanochannels are outlined, which involves
biological and chemical analysis, and energy conversion.

http://iopscience.iop.org/0957-4484/25/12/122001 2014/02/27 - 01:24

The AdS/CFT correspondence relates certain strongly-coupled CFTs with large effective central charge
c eff to semi-classical gravitational theories with AdS asymptotics. We describe recent progress in
understanding gravity duals for CFTs on non-trivial spacetimes at finite temperature, both in and
out of equilibrium. Such gravity methods provide powerful new tools to access the physics of these
strongly-coupled theories, which often differs qualitatively from that found at weak coupling. Our
discussion begins with basic aspects of AdS/CFT and progresses through thermal CFTs on the Einstein
Static Universe and on periodically identified Minkowski spacetime. In the latter context we focus
on states describing so-called plasma-balls, which become stable at large c eff . We then proceed to
out-of-equilibrium situations associated with dynamical bulk black holes. In particular, the
non-compact nature of these bulk black holes allows stationary solution...

http://iopscience.iop.org/0264-9381/31/6/063001 2014/02/22 - 13:56

After the revival of the magnetoelectric effect which took place in the early 2000s, the interest in
multiferroic materials displaying simultaneous presence of spontaneous long-range magnetic and
dipolar order has motivated an exponential growth of research activity, from both the experimental
and theoretical perspectives. Within this context, and relying also on the rigorous formulation of
macroscopic polarization as provided by the Berry-phase approach, it has been possible to identify
new microscopic mechanisms responsible for the appearance of ferroelectricity. In particular, it has
been realized that electronic spin, charge and orbital degrees of freedom may be responsible for the
breaking of the space-inversion symmetry, a necessary condition for the appearance of electric
polarization, even in centrosymmetric crystal structures. In view of its immediate potential
application in magnetoelectric-based devices, many efforts have been made to understand how magnetic
orderings ...

http://iopscience.iop.org/0953-8984/26/10/103201 2014/02/19 - 18:47

Atomistic modelling of magnetic materials provides unprecedented detail about the underlying
physical processes that govern their macroscopic properties, and allows the simulation of complex
effects such as surface anisotropy, ultrafast laser-induced spin dynamics, exchange bias, and
microstructural effects. Here we present the key methods used in atomistic spin models which are
then applied to a range of magnetic problems. We detail the parallelization strategies used which
enable the routine simulation of extended systems with full atomistic resolution.

http://iopscience.iop.org/0953-8984/26/10/103202 2014/02/19 - 18:47

A review on silica clathrate compounds, which are variants of pure silica zeolites with relatively
small voids, is presented. Zeolites have found many uses in industrial and domestic settings as
materials for catalysis, separations, adsorption, ion exchange, drug delivery, and other
applications. Zeolites with pure silica frameworks have attracted particular interest because of
their high thermal stability, well-characterized framework structures, and simple chemical
compositions. Recent advances in new synthetic routes have extended the structural diversity of pure
silica zeolite frameworks. Thermochemical analyses and computational simulations have provided a
basis for applications of these materials and the syntheses of new types of pure silica zeolites.
High-pressure and high-temperature experiments have also revealed diverse responses of these
framework structures to pressure, temperature, and various guest species. This paper summarizes the
framework topologies, synthetic p...

http://iopscience.iop.org/0953-8984/26/10/103203 2014/02/19 - 18:47

Although cosmic rays were discovered over 100 years ago their origin remains uncertain. They have an
energy spectrum that extends from ∼1 GeV to beyond 10 20 eV, where the rate is less than 1 particle
per km 2 per century. Shortly after the discovery of the cosmic microwave background in 1965, it was
pointed out that the spectrum of cosmic rays should steepen fairly abruptly above about 4 × 10 19
 eV, provided the sources are distributed uniformly throughout the Universe. This prediction, by
Greisen and by Zatsepin and Kuz'min, has become known as the GZK effect and in this article I
discuss the current position with regard to experimental data on the energy spectrum of the highest
cosmic-ray energies that have been accumulated in a search that has lasted nearly 50 years. Although
there is now little doubt that a suppression of the spectrum exists near the energy predicted, it is
by no means certain that this is a manifestation of the GZK effect as it...

http://iopscience.iop.org/0034-4885/77/3/036901 2014/02/19 - 18:47