764 research outputs found
Si_3N_4 optomechanical crystals in the resolved-sideband regime
We demonstrate sideband-resolved optomechanical crystals supporting 10^5 quality factor optical modes at 980 nm, coupled to  GHz frequency mechanical modes with quality factors of ≈3000. Optomechanical electromagnetically induced transparency and absorption are observed at room temperature and in atmosphere with intracavity photon numbers in excess of 10^4
Characterization and evaluation of Paulownia elongota as a raw material for paper production
Paulownia elongota, one of the most fast growing species of the world, was evaluated as raw material for pulp and paper production. The chemical, morphological and anatomical aspects of paulownia woodwere determined. The lignin, holocellulose and ∝-cellulose contents in P. elongota wood were comparable to those of some common non-wood and hardwood raw materials. Different chemical pulping procedures were applied to P. elongota wood to evaluate its pulping potential. Paper strength properties and acidic group content bound to the cell wall were determined. The alkali solubility, water solubility and alcohol-benzene extractive content were higher than those from wood and most nonwoods. The fiber length of 0.83 mm was observed, which is close to low end of the hardwoods but fiber diameter was very wide, similar to that of softwoods. The pulpability of paulownia wood was alsostudied. The pulp yield and viscosity were very low and the kappa numbers were high. The strength properties were comparable to those of some wood and non-wood pulps. Although, paulownia pulpsare considered as low quality materials, it can be used for paper production when mixed with long fibrous materials
Genome-scale reconstruction of metabolic network for a halophilic extremophile, Chromohalobacter salexigens DSM 3043
<p>Abstract</p> <p>Background</p> <p><it>Chromohalobacter salexigens </it>(formerly <it>Halomonas elongata </it>DSM 3043) is a halophilic extremophile with a very broad salinity range and is used as a model organism to elucidate prokaryotic osmoadaptation due to its strong euryhaline phenotype.</p> <p>Results</p> <p><it>C. salexigens </it>DSM 3043's metabolism was reconstructed based on genomic, biochemical and physiological information via a non-automated but iterative process. This manually-curated reconstruction accounts for 584 genes, 1386 reactions, and 1411 metabolites. By using flux balance analysis, the model was extensively validated against literature data on the <it>C. salexigens </it>phenotypic features, the transport and use of different substrates for growth as well as against experimental observations on the uptake and accumulation of industrially important organic osmolytes, ectoine, betaine, and its precursor choline, which play important roles in the adaptive response to osmotic stress.</p> <p>Conclusions</p> <p>This work presents the first comprehensive genome-scale metabolic model of a halophilic bacterium. Being a useful guide for identification and filling of knowledge gaps, the reconstructed metabolic network <it>i</it>OA584 will accelerate the research on halophilic bacteria towards application of systems biology approaches and design of metabolic engineering strategies.</p
Polysulfone/Clay Nanocomposites by in situ Photoinduced Crosslinking Polymerization
Cataloged from PDF version of article.PSU/MMT nanocomposites are prepared by dispersing MMT nanolayers in a PSU matrix via in situ photoinduced crosslinking polymerization. Intercalated methacrylate-functionalized MMT and polysulfone dimethacrylate macromonomer are synthesized independently by esterification. In situ photoinduced crosslinking of the intercalated monomer and the PSU macromonomer in the silicate layers leads to nanocomposites that are formed by individually dispersing inorganic silica nanolayers in the polymer matrix. The morphology of the nanocomposites is investigated by XRD and TEM, which suggests the random dispersion of silicate layers in the PSU matrix. TGA results confirm that the thermal stability and char yield of PSU/MMT nanocomposites increases with the increase of clay loading
Scheduling Task-parallel Applications in Dynamically Asymmetric Environments
Shared resource interference is observed by applications as dynamic
performance asymmetry. Prior art has developed approaches to reduce the impact
of performance asymmetry mainly at the operating system and architectural
levels. In this work, we study how application-level scheduling techniques can
leverage moldability (i.e. flexibility to work as either single-threaded or
multithreaded task) and explicit knowledge on task criticality to handle
scenarios in which system performance is not only unknown but also changing
over time. Our proposed task scheduler dynamically learns the performance
characteristics of the underlying platform and uses this knowledge to devise
better schedules aware of dynamic performance asymmetry, hence reducing the
impact of interference. Our evaluation shows that both criticality-aware
scheduling and parallelism tuning are effective schemes to address interference
in both shared and distributed memory applicationsComment: Published in ICPP Workshops '2
Phase-imprinting of Bose-Einstein condensates with Rydberg impurities
We show how the phase profile of Bose-Einstein condensates can be engineered through its in- teraction with localized Rydberg excitations. The interaction is made controllable and long-range by off-resonantly coupling the condensate to another Rydberg state with laser light. Our technique allows the mapping of entanglement generated in systems of few strongly interacting Rydberg atoms onto much larger atom clouds in hybrid setups. As an example we discuss the creation of a spatial mesoscopic superposition state from a bright soliton. Additionally, the phase imprinted onto the condensate using the Rydberg excitations is a diagnostic tool for the latter. For example a condensate time-of-flight image would permit reconstructing the pattern of an embedded Rydberg crystal
Boosting up quantum key distribution by learning statistics of practical single photon sources
We propose a simple quantum-key-distribution (QKD) scheme for practical
single photon sources (SPSs), which works even with a moderate suppression of
the second-order correlation of the source. The scheme utilizes a
passive preparation of a decoy state by monitoring a fraction of the signal via
an additional beam splitter and a detector at the sender's side to monitor
photon number splitting attacks. We show that the achievable distance increases
with the precision with which the sub-Poissonian tendency is confirmed in
higher photon number distribution of the source, rather than with actual
suppression of the multi-photon emission events. We present an example of the
secure key generation rate in the case of a poor SPS with , in
which no secure key is produced with the conventional QKD scheme, and show that
learning the photon-number distribution up to several numbers is sufficient for
achieving almost the same achievable distance as that of an ideal SPS.Comment: 11 pages, 3 figures; published version in New J. Phy
Subhepatically located appendicitis due to adhesions: a case report
<p>Abstract</p> <p>Introduction</p> <p>Acute appendicitis occurs frequently and is a major indication for acute abdominal surgery. Subhepatic appendicitis has rarely been reported and is more difficult to diagnose.</p> <p>Case presentation</p> <p>A 71-year-old man with multiple medical comorbidities presented with undifferentiated right abdominal pain. Diagnostic difficulty was encountered due to subhepatic mal-location of the appendix and subsequently atypical presentation for acute appendicitis.</p> <p>Conclusion</p> <p>Subhepatic anatomical location of the appendix makes it more difficult to diagnose acute appendicitis at any age, including in older adults.</p
Emission spectra and intrinsic optical bistability in a two-level medium
Scattering of resonant radiation in a dense two-level medium is studied
theoretically with account for local field effects and renormalization of the
resonance frequency. Intrinsic optical bistability is viewed as switching
between different spectral patterns of fluorescent light controlled by the
incident field strength. Response spectra are calculated analytically for the
entire hysteresis loop of atomic excitation. The equations to describe the
non-linear interaction of an atomic ensemble with light are derived from the
Bogolubov-Born-Green-Kirkwood-Yvon hierarchy for reduced single particle
density matrices of atoms and quantized field modes and their correlation
operators. The spectral power of scattered light with separated coherent and
incoherent constituents is obtained straightforwardly within the hierarchy. The
formula obtained for emission spectra can be used to distinguish between
possible mechanisms suggested to produce intrinsic bistability.Comment: 18 pages, 5 figure
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