181 research outputs found
Graphene as Infrared Light Sensor Material
The infrared (IR) photoresponse of graphene synthesized by an atmospheric
chemical vapor deposition (CVD) system using a mixture of hydrogen and methane
gases was studied. The IR sensor devices were fabricated using graphene films
transferred onto a SiO2 substrate by a lift-off process. The quality of
graphene was investigated with Raman spectroscopy and optical microscopy. The
photoresponse was recorded under the illumination of IR light of wavelength 850
nm and intensity of around 0.216 mW/cm^2. The effects of temperature and
hydrogenation on photoconductivity were also studied. It was found that the
transient response and recovery times decreased with the temperature increase.
The hydrogenation effect also caused a significant decrease in the
photoresponse of the device. Although the net change in the photoresponse for
IR light was lower at low illumination intensity levels, the transient
responses were observed around 100 times faster than the recently reported
CNT-based IR sensors.Comment: 8 pages, 8 pictures, and 1 table
Review on Master Patient Index
In today's health care establishments there is a great diversity of
information systems. Each with different specificities and capacities,
proprietary communication methods, and hardly allow scalability. This set of
characteristics hinders the interoperability of all these systems, in the
search for the good of the patient. It is vulgar that, when we look at all the
databases of each of these information systems, we come across different
registers that refer to the same person; records with insufficient data;
records with erroneous data due to errors or misunderstandings when inserting
patient data; and records with outdated data. These problems cause duplicity,
incoherence, discontinuation and dispersion in patient data. With the intention
of minimizing these problems that the concept of a Master Patient Index is
necessary. A Master Patient Index proposes a centralized repository, which
indexes all patient records of a given set of information systems. Which is
composed of a set of demographic data sufficient to unambiguously identify a
person and a list of identifiers that identify the various records that the
patient has in the repositories of each information system. This solution
allows for synchronization between all the actors, minimizing incoherence, out
datedness, lack of data, and a decrease in duplicate registrations. The Master
Patient Index is an asset to patients, the medical staff and health care
providers
Structure of 10N in 9C+p resonance scattering
The structure of exotic nucleus 10N was studied using 9C+p resonance
scattering. Two L=0 resonances were found to be the lowest states in 10N. The
ground state of 10N is unbound with respect to proton decay by 2.2(2) or 1.9(2)
MeV depending on the 2- or 1- spin-parity assignment, and the first excited
state is unbound by 2.8(2) MeV.Comment: 6 pages, 4 figures, 1 table, submitted to Phys. Lett.
Successive Cambia in the mangrove <i>Avicennia</i>: A study on the three-dimensional structure of the Cambia and the functioning of the internal phloem tissue
Mangrove forests grow in conditions which must be considered extreme for woody angiosperms: high and changing salinity, frequent inundation with associated hypoxia, low relative humidity of the air and high temperatures. As ‘marine formations’, mangrove ecosystems are characteristic for the intertidal area of estuaries, creeks, sheltered bays and coastlines in tropical and sub-tropical areas worldwide. The genus Avicennia has been shown to be eurytopic as regards the above mentioned environmental conditions. Locally, Avicennia can often be found at the seaward as well as at the landward side (Disjunct zonation pattern) of the mangrove forest, sites with highly contrasting environmental conditions, while globally it has the largest latitudinal range in both the Eastern and the Western biogeographic mangrove regions (i.e. Indo-West Pacific and East Africa vs. America and West Africa respectively). The question is how Avicennia copes with this large and varying range of environmental conditions? It already has been proven that the wood anatomy of Avicennia is especially adapted to harsh environmental conditions. Properties of the wood (transport tissues) were suggested to be adapted to reduce cavitation events, defined as air bubble formation in the xylem sap. Inside vessels, those air bubbles can enlarge and therewith block the water transport (i.e. vessel embolism) so that cavitation and subsequent embolism is highly influencing the functionality of the hydraulic system. Amongst mangrove trees, the genus Avicennia L. (Acanthaceae) stands out by its successive cambia (i.e. having not one cambial layer but subsequent active cambia possibly conferring many sites of active growth in the stem). Secondary growth by successive cambia can offer Avicennia ecological advantages since (1) the internal phloem tissue can store water that could be used in refilling air-filled vessels with water and (2) the special, patchy growth can offer the tree woody tissue that is well-adapted to the conditions of the moment. In this study we investigate the organization of the successive cambia in Avicennia in three dimensions in order to complete the already investigated three dimensional network of transport tissues (phloem and xylem). Small stems (max. diameter: 3 cm) and branches of Avicennia marina (Forssk.) Vierh. and A. officinalis L. were sampled from the Rekawa lagoon in Sri Lanka, where the two species encounter spatially and temporally varying conditions as regards salinity, inundation. Serial sections and microscopic observation of the samples allow the reconstruction and visualization of the three-dimensional organization of the successive cambia. The working hypothesis of the research is: ‘successive cambia are important for Avicennia to survive in extreme high environmental conditions and explains the genus eurytopic nature as compared to other mangrove genera’
Nuclear structure beyond the neutron drip line: the lowest energy states in He via their T=5/2 isobaric analogs in Li
The level structure of the very neutron rich and unbound He nucleus has
been the subject of significant experimental and theoretical study. Many recent
works have claimed that the two lowest energy He states exist with spins
and and widths on the order of hundreds of keV.
These findings cannot be reconciled with our contemporary understanding of
nuclear structure. The present work is the first high-resolution study with low
statistical uncertainty of the relevant excitation energy range in the
He system, performed via a search for the T=5/2 isobaric analog states
in Li populated through He+p elastic scattering. The present data show
no indication of any narrow structures. Instead, we find evidence for a broad
state in He located approximately 3 MeV above the neutron
decay threshold
alpha-cluster structure of 18Ne
In this work we study alpha-clustering in 18Ne and compare it with what is
known about clustering in the mirror nucleus 18O. The excitation function of
18Ne was measured in inverse kinematics from the resonant elastic scattering
reaction of 14O on 4He in the excitation energy range from 8 to 17 MeV, using
the active target TexAT. The analysis was performed using a multi-channel
R-matrix approach. Detailed spectroscopic information is obtained from the
R-matrix analysis: excitation energy of the states, spin and parity as well as
partial alpha and total widths. This information is compared with theoretical
models and previous data. Clustering structures appear to be robust and mostly
isospin symmetric. A good correspondence was found between the levels in 18O
and 18Ne. We carried out an extensive shell model analysis of the experimental
data. This comparison suggests that strongly clustered states remain organized
in relation to the corresponding reaction channel identified by the number of
nodes in the relative alpha plus core wave function. The agreement between
theory and experiment is very good and especially useful when it comes to
understanding the clustering strength distribution. The comparison of the
experimental data with theory shows that certain states, especially at high
excitation energies, are significantly more clustered than predicted. This
indicates that the structure of these states is collective and is aligned
towards the corresponding alpha reaction channel
Study of the Mg waiting point relevant for x-ray burst nucleosynthesis via the Mg(,)Al reaction
The Mg(,)Al reaction rate has been identified as a
major source of uncertainty for understanding the nucleosynthesis flow in
Type-I x-ray bursts (XRBs). We report a direct measurement of the energy- and
angle-integrated cross sections of this reaction in a 3.3-6.9 MeV
center-of-mass energy range using the MUlti-Sampling Ionization Chamber
(MUSIC). The new Mg(,)Al reaction rate is a factor of
4 higher than the previous direct measurement of this reaction within
temperatures relevant for XRBs, resulting in the Mg waiting point of
x-ray burst nucleosynthesis flow to be significantly bypassed via the
() reactionComment: 6 pages, 3 figures, 1 tabl
Decay properties of resonances and their impact on -process nucleosynthesis
The astrophysical -process is one of the two main processes forming
elements heavier than iron. A key outstanding uncertainty surrounding
-process nucleosynthesis is the neutron flux generated by the
reaction during the He-core
and C-shell burning phases of massive stars. This reaction, as well as the
competing reaction, is
not well constrained in the important temperature regime from --~GK, owing to uncertainties in the nuclear properties of resonances
lying within the Gamow window. To address these uncertainties, we have
performed a new measurement of the reaction in inverse kinematics, detecting the outgoing
deuterons and recoils in coincidence. We have
established a new decay branching ratio of for the key
MeV resonance in , which results in a new
strength for this resonance of eV when combined with
the well-established strength of this resonance. We have
also determined new upper limits on the partial widths of
neutron-unbound resonances at , , and
MeV. Monte-Carlo calculations of the stellar and rates, which incorporate these results, indicate
that both rates are substantially lower than previously thought in the
temperature range from --~GK.Comment: 17 pages, 4 figures, accepted for publication in Phys. Lett.
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