160 research outputs found
Efficient Performance of Electrostatic Spray-Deposited TiO2 Blocking Layers in Dye-Sensitized Solar Cells after Swift Heavy Ion Beam Irradiation
A compact TiO2 layer (~1.1 μm) prepared by electrostatic spray deposition (ESD) and swift heavy ion beam (SHI) irradiation using oxygen ions onto a fluorinated tin oxide (FTO) conducting substrate showed enhancement of photovoltaic performance in dye-sensitized solar cells (DSSCs). The short circuit current density (Jsc = 12.2 mA cm-2) of DSSCs was found to increase significantly when an ESD technique was applied for fabrication of the TiO2 blocking layer, compared to a conventional spin-coated layer (Jsc = 8.9 mA cm-2). When SHI irradiation of oxygen ions of fluence 1 × 1013 ions/cm2 was carried out on the ESD TiO2, it was found that the energy conversion efficiency improved mainly due to the increase in open circuit voltage of DSSCs. This increased energy conversion efficiency seems to be associated with improved electronic energy transfer by increasing the densification of the blocking layer and improving the adhesion between the blocking layer and the FTO substrate. The adhesion results from instantaneous local melting of the TiO2 particles. An increase in the electron transport from the blocking layer may also retard the electron recombination process due to the oxidized species present in the electrolyte. These findings from novel treatments using ESD and SHI irradiation techniques may provide a new tool to improve the photovoltaic performance of DSSCs
A Modified Consumer Inkjet for Spatiotemporal Control of Gene Expression
This paper presents a low-cost inkjet dosing system capable of continuous, two-dimensional spatiotemporal regulation of gene expression via delivery of diffusible regulators to a custom-mounted gel culture of E. coli. A consumer-grade, inkjet printer was adapted for chemical printing; E. coli cultures were grown on 750 µm thick agar embedded in micro-wells machined into commercial compact discs. Spatio-temporal regulation of the lac operon was demonstrated via the printing of patterns of lactose and glucose directly into the cultures; X-Gal blue patterns were used for visual feedback. We demonstrate how the bistable nature of the lac operon's feedback, when perturbed by patterning lactose (inducer) and glucose (inhibitor), can lead to coordination of cell expression patterns across a field in ways that mimic motifs seen in developmental biology. Examples of this include sharp boundaries and the generation of traveling waves of mRNA expression. To our knowledge, this is the first demonstration of reaction-diffusion effects in the well-studied lac operon. A finite element reaction-diffusion model of the lac operon is also presented which predicts pattern formation with good fidelity
What is a smart device? - a conceptualisation within the paradigm of the internet of things
The Internet of Things (IoT) is an interconnected network of objects which range from simple sensors to smartphones and tablets; it is a relatively novel paradigm that has been rapidly gaining ground in the scenario of modern wireless telecommunications with an expected growth of 25 to 50 billion of connected devices for 2020 Due to the recent rise of this paradigm, authors across the literature use inconsistent terms to address the devices present in the IoT, such as mobile device, smart device, mobile technologies or mobile smart device. Based on the existing literature, this paper chooses the term smart device as a starting point towards the development of an appropriate definition for the devices present in the IoT. This investigation aims at exploring the concept and main features of smart devices as well as their role in the IoT. This paper follows a systematic approach for reviewing compendium of literature to explore the current research in this field. It has been identified smart devices as the primary objects interconnected in the network of IoT, having an essential role in this paradigm. The developed concept for defining smart device is based on three main features, namely context-awareness, autonomy and device connectivity. Other features such as mobility and userinteraction were highly mentioned in the literature, but were not considered because of the nature of the IoT as a network mainly oriented to device-to-device connectivity whether they are mobile or not and whether they interact with people or not. What emerges from this paper is a concept which can be used to homogenise the terminology used on further research in the Field of digitalisation and smart technologies
Study of in the vicinity of
Using 2917 of data accumulated at 3.773~,
44.5~ of data accumulated at 3.65~ and data accumulated
during a line-shape scan with the BESIII detector, the reaction
is studied considering a possible interference
between resonant and continuum amplitudes. The cross section of
,
, is found to have two
solutions, determined to be () pb with the phase angle
(0.11 pb at the 90% confidence level),
or ) pb with both of which
agree with a destructive interference. Using the obtained cross section of
, the cross section of , which is useful information for the future PANDA experiment, is
estimated to be either () nb ( nb at 90% C.L.) or
nb
Nucleophilic Functionalization of the Calix[6]arene Para- and Meta-Position via p‑Bromodienone Route
It is here demonstrated that the p-bromodienone route,
previously reported for calix[4]arenes, is also effective for the functionalization
of the calix[6]arene macrocycle. Thus, alcoholic O-nucleophiles can be
introduced at the calix[6]arene exo rim. In addition, the reaction of a
calix[6]arene p-bromodienone derivative with an actived aromatic substrate,
such as resorcinol, led to the first example of a meta-functionalized,
inherently chiral calix[6]arene derivativ
Direct measurement of the exciton binding energy and effective masses for charge carriers in organic–inorganic tri-halide perovskites
Solar cells based on the organic-inorganic tri-halide perovskite family of
materials have shown remarkable progress recently, offering the prospect of
low-cost solar energy from devices that are very simple to process. Fundamental
to understanding the operation of these devices is the exciton binding energy,
which has proved both difficult to measure directly and controversial. We
demonstrate that by using very high magnetic fields it is possible to make an
accurate and direct spectroscopic measurement of the exciton binding energy,
which we find to be only 16 meV at low temperatures, over three times smaller
than has been previously assumed. In the room temperature phase we show that
the binding energy falls to even smaller values of only a few
millielectronvolts, which explains their excellent device performance due to
spontaneous free carrier generation following light absorption. Additionally,
we determine the excitonic reduced effective mass to be 0.104me (where me is
the electron mass), significantly smaller than previously estimated
experimentally but in good agreement with recent calculations. Our work
provides crucial information about the photophysics of these materials, which
will in turn allow improved optoelectronic device operation and better
understanding of their electronic properties
The Power Board of the KM3NeT Digital Optical Module: design, upgrade, and production
The KM3NeT Collaboration is building an underwater neutrino observatory at
the bottom of the Mediterranean Sea consisting of two neutrino telescopes, both
composed of a three-dimensional array of light detectors, known as digital
optical modules. Each digital optical module contains a set of 31 three inch
photomultiplier tubes distributed over the surface of a 0.44 m diameter
pressure-resistant glass sphere. The module includes also calibration
instruments and electronics for power, readout and data acquisition. The power
board was developed to supply power to all the elements of the digital optical
module. The design of the power board began in 2013, and several prototypes
were produced and tested. After an exhaustive validation process in various
laboratories within the KM3NeT Collaboration, a mass production batch began,
resulting in the construction of over 1200 power boards so far. These boards
were integrated in the digital optical modules that have already been produced
and deployed, 828 until October 2023. In 2017, an upgrade of the power board,
to increase reliability and efficiency, was initiated. After the validation of
a pre-production series, a production batch of 800 upgraded boards is currently
underway. This paper describes the design, architecture, upgrade, validation,
and production of the power board, including the reliability studies and tests
conducted to ensure the safe operation at the bottom of the Mediterranean Sea
throughout the observatory's lifespa
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