10 research outputs found
High Efficient Photodegradation and Photocatalytic Hydrogen Production of CdS/BiVO<sub>4</sub> Heterostructure through <i>Z</i>‑Scheme Process
Novel heterostructured
CdS/BiVO<sub>4</sub> nanocomposites were
fabricated in a low-temperature water bath system. The uniform CdS
nanoparticles with an average size of 20 nm were homogeneously interspersed
on BiVO<sub>4</sub> nanosheets. The coupling of BiVO<sub>4</sub> and
CdS nanoparticles could notably promote the photocatalytic activity.
The composites reached a high H<sub>2</sub>-production rate of 0.57
mmol h<sup>–1</sup> under visible light irradiation, about
5.18 times higher than that of pure CdS nanoparticles. The dominant
active species in the photocatalytic system were also confirmed by
the radical trapping test. Based on the calculation and experimental
results, a <i>Z</i>-scheme photocatalytic mechanism was
proposed, which was further confirmed by the electrochemical impedance
spectroscopy and the cycling test. The <i>Z</i>-scheme photocatalytic
system endows the CdS/BiVO<sub>4</sub> heterostructure with strong
reducibility and oxidizability and excellent stability
(Pc)Eu(Pc)Eu[<i>trans</i>-T(COOCH<sub>3</sub>)<sub>2</sub>PP]/GO Hybrid Film-Based Nonenzymatic H<sub>2</sub>O<sub>2</sub> Electrochemical Sensor with Excellent Performance
A facile
approach was developed for preparing the multilayer hybrid films of
mixed (phthalocyaninato) (porphyrinato) europiumÂ(III) triple-decker
compound (Pc)ÂEuÂ(Pc)ÂEuÂ[<i>trans</i>-TÂ(COOCH<sub>3</sub>)<sub>2</sub>PP] (<b>1</b>) and graphene oxide (GO) using the solution-processing
QLS method. The combination of the nature of relatively high conductivity
and great surface area for GO with the electroactive and semiconductive
triple-decker compound in ITO electrode renders the hybrid film excellent
sensing property for H<sub>2</sub>O<sub>2</sub>, due to the optimized
triple-decker molecular packing in the uniform-sized nanoparticles
(ca. 70 nm) formed on the GO surface. The amperometric responses are
linearly proportional to the concentration of H<sub>2</sub>O<sub>2</sub> in the range of 0.05–1800 μM with a fast response time
of 0.03 s μM<sup>–1</sup>, a low detection limit of 0.017
μM, and good sensitivity of 7.4 μA mM<sup>–1</sup>. The present work represents the best result of tetrapyrrole-based
nonenzymatic electrochemical sensor for H<sub>2</sub>O<sub>2</sub>. Nevertheless, the triple-decker/GO/ITO also shows excellent stability,
reproducibility, and selectivity, indicating the great potential of
electroactive tetrapyrrole rare earth sandwich compounds in combination
with GO in the field of nonenzymatic electrochemical sensors
Magnetically Separable CdS/ZnFe<sub>2</sub>O<sub>4</sub> Composites with Highly Efficient Photocatalytic Activity and Photostability under Visible Light
Novel
CdS/ZnFe<sub>2</sub>O<sub>4</sub> composites were prepared
through a two-step hydrothermal process. The homogeneous ZnFe<sub>2</sub>O<sub>4</sub> nanoparticles are decorated on the self-assembled
CdS spheres. Compared to those of pure CdS and blank ZnFe<sub>2</sub>O<sub>4</sub>, the photocatalytic activity and stability of the magnetically
separable CdS/ZnFe<sub>2</sub>O<sub>4</sub> composites are considerably
increased. The results of photoluminescence and electrochemical impedance
spectroscopy further validate that the performance enhancement results
from the construction of heterojunction structure, leading to high
charge separation efficiency. On the basis of the calculation and
the trapping test, a heterojunction photocatalytic mechanism is proposed
Table_1_Evaluation of peri-plaque pericoronary adipose tissue attenuation in coronary atherosclerosis using a dual-layer spectral detector CT.DOCX
PurposeThis study aimed to evaluate the differences between pericoronary adipose tissue (PCAT) attenuation at different measured locations in evaluating coronary atherosclerosis using spectral computed tomography (CT) and to explore valuable imaging indicators.MethodsA total of 330 patients with suspicious coronary atherosclerosis were enrolled and underwent coronary CT angiography with dual-layer spectral detector CT (SDCT). Proximal and peri-plaque fat attenuation index (FAI) of stenosis coronary arteries were measured using both conventional images (CIs) and virtual monoenergetic images (VMIs) ranging from 40 keV to 100 keV. The slopes of the spectral attenuation curve (λ) of proximal and peri-plaque PCAT at three different monoenergetic intervals were calculated. Additionally, peri-plaque FAI on CI and virtual non-contrast images, and effective atomic number were measured manually.ResultsA total of 231 coronary arteries with plaques and lumen stenosis were finally enrolled. Peri-plaque FAICI and FAIVMI were significantly higher in severe stenosis than in mild and moderate stenosis (p ConclusionPeri-plaque PCAT has more value in assessing coronary atherosclerosis than proximal PCAT. Peri-plaque PCAT attenuation is expected to be used as a standard biomarker for evaluating plaque vulnerability and hemodynamic characteristics.</p
Distributed filtering for complex networks under multiple event-triggered transmissions within node-wise communications
This paper focuses on the distributed filtering and fault estimation problems for a class of complex networks, where the communications between filters at different nodes are subject to dynamic event-triggered (DET) transmissions. A filter is constructed at each node by resorting to local measurements and information from neighboring nodes and thus the developed algorithm can be carried out distributedly. Different from the clock-driven signal transmissions in traditional distributed filtering schemes, the transmissions of both state estimates and the upper bounds of filtering error covariances (FECs) between the nodes are monitored by a multiple DET strategy to reduce unnecessary burdens in the links. Under DET transmissions, an upper bound of the FEC is obtained and then minimized via parameterizing the filter recursively. Novel sufficient conditions, which are dependent on locally available information, are provided to guarantee the uniform boundedness of the FEC at each node. The proposed method is used to solve the fault estimation problem in complex networks, where the estimation error is ensured to be exponentially bounded. Some illustrative examples are employed to show the effectiveness of our algorithm
Image_1_Evaluation of peri-plaque pericoronary adipose tissue attenuation in coronary atherosclerosis using a dual-layer spectral detector CT.TIF
PurposeThis study aimed to evaluate the differences between pericoronary adipose tissue (PCAT) attenuation at different measured locations in evaluating coronary atherosclerosis using spectral computed tomography (CT) and to explore valuable imaging indicators.MethodsA total of 330 patients with suspicious coronary atherosclerosis were enrolled and underwent coronary CT angiography with dual-layer spectral detector CT (SDCT). Proximal and peri-plaque fat attenuation index (FAI) of stenosis coronary arteries were measured using both conventional images (CIs) and virtual monoenergetic images (VMIs) ranging from 40 keV to 100 keV. The slopes of the spectral attenuation curve (λ) of proximal and peri-plaque PCAT at three different monoenergetic intervals were calculated. Additionally, peri-plaque FAI on CI and virtual non-contrast images, and effective atomic number were measured manually.ResultsA total of 231 coronary arteries with plaques and lumen stenosis were finally enrolled. Peri-plaque FAICI and FAIVMI were significantly higher in severe stenosis than in mild and moderate stenosis (p ConclusionPeri-plaque PCAT has more value in assessing coronary atherosclerosis than proximal PCAT. Peri-plaque PCAT attenuation is expected to be used as a standard biomarker for evaluating plaque vulnerability and hemodynamic characteristics.</p
Joint state and fault estimation of complex networks under measurement saturations and stochastic nonlinearities
In this paper, the joint state and fault estimation problem is investigated for a class of discrete-time complex networks with measurement saturations and stochastic nonlinearities. The difference between the actual measurement and the saturated measurement is regarded as an unknown input and the system is thus re-organized as a singular system. An appropriate estimator is designed for each node which aims to estimate the system states and the loss of the actuator effectiveness simultaneously. In the presence of measurement saturations and stochastic nonlinearities, upper bounds of the error covariances of the fault estimates are recursively obtained and then minimized. Sufficient conditions are proposed to guarantee the existence and the unbiasedness of the developed estimator. Our developed estimator design algorithm is distributed because it depends only on the local information and the information from the neighboring subsystems, thereby avoiding the usage of a center estimator. Finally, simulation results are presented to show the performance of the proposed strategy in simultaneously estimating the states and faults
A cyberinfrastructure for community resilience assessment and visualization
<div><p>Disaster resilience is a major societal challenge. Cartography and GIS can contribute substantially to this research area. This paper describes a cyberinfrastructure for disaster resilience assessment and visualization for all counties in the United States. Aided by the Application Programming Interface-enabled web mapping and component-oriented web tools, the cyberinfrastructure is designed to better serve the US communities with comprehensive resilience information. The resilience assessment tool is based on the resilience inference measurement model. This web application delivers the resilience assessment tool to the users through applets. It provides an interactive tool for the users to visualize the historical natural hazards exposure and damages in the areas of their interest, compute the resilience indices, and produce on-the-fly maps and statistics. The app could serve as a useful tool for decision makers. This app won the top 10 runners-up in the Environmental Systems Research Institute (ESRI) Climate Resilience App Challenge 2014 and the top 5 in the scientific section of the ESRI Global Disaster App Challenge 2014.</p></div
One-Pot Synthesis of Indole-3-acetic Acid Derivatives through the Cascade Tsuji–Trost Reaction and Heck Coupling
A practical
palladium-mediated cascade Tsuji–Trost reaction/Heck
coupling of N-Ts <i>o</i>-bromoanilines with 4-acetoxy-2-butenonic
acid derivatives using a PdÂ(OAc)<sub>2</sub>/PÂ(<i>o</i>-tol)<sub>3</sub>/DIPEA system is described for a straightforward synthesis
of indole-3-acetic acid derivatives. This methodology was successfully
applied to synthesize various substituted indole/azaindole-3-acetic
acid derivatives and Almotriptan, which is a drug for the acute treatment
of migraines. Moreover, a plausible cyclization mechanism has been
proposed
Resolving the Difference in Electric Potential within a Charged Macromolecule
The
difference of the electric potential between the middle and
end of polystyrenesulfonate (PSS<sup>–</sup>) chain is discovered
experimentally. Using a pH-responsive fluorophore attached to these
two locations on the PSS<sup>–</sup> chain, the local pH value
was determined by single molecule fluorescence technique: photon counting
histogram (PCH). By the observation of a very high accumulation of
proton (2–3 orders of magnitude in concentration) at the vicinity
of the PSS<sup>–</sup> as a result of the electrostatic attraction
between the charged chain and protons, the electric potential of the
PSS<sup>–</sup> chain is determined. A higher extent of counterion
adsorption is discovered at the middle of the PSS<sup>–</sup> chain than the chain end. The entropy effect of the counterion adsorption
is also discoveredî—¸upon the dilution of protons, previously
adsorbed counterions are detached from the chain