Accurate and stable short-term traffic flow prediction is an indispensable part in current intelligent transportation systems. In this paper, a novel short-term traffic flow forecasting model termed ...as EnLSTM-WPEO is proposed based on ensemble learning of long short term memory neural network (LSTM), no negative constraint theory (NNCT) weight integration and population extremal optimization (PEO) algorithm. In the first stage, a cluster of LSTMs is constructed to separately forecast with different time lag, which is a significant element to affect the prediction performance. In the second stage, the PEO-based NNCT weight integration strategy is introduced to determine the weight coefficients of the ensemble model. The simulation results for six different datasets from highways of Seattle have testified the superiority of the proposed EnLSTM-WPEO to other six popular traffic flow forecasting models in terms of two commonly used performance indices and three statistical tests.
Understanding the change in coal structure during heat treatment is the basis of efficient and clean utilization of coal. In this study, high-resolution transmission electron microscopy (HRTEM) was ...used to analyse the changes in the aggregate structure and ultramicropores of Zhungdong coal samples (Xinjiang, China) that were heated from ambient temperature to 800 °C respectively. Then, the relationship between their HRTEM characteristics and the corresponding reaction activation energy were also analyzed. The results show that the length, curvature, order, layer spacing and stacking height of the aromatic layers of the coal sample vary with an increasing temperature, and are related to the activation energy of the reaction. As the temperature reaches 300 °C, the HRTEM characteristics of the heated coal samples are obviously different from those of the raw coal sample. It is shown that the length of lattice fringes is in the range of 0.3-1.15 nm which accounts for approximately 95% of the total number of fringes. The overall orientation of lattice fringes is not good, but there are two main directions. After heating, the number of naphthalenes in the coal samples decreased, while the number of larger aromatic layers increased. The distance between the aromatic layers of the coal sample decreased with an increasing stacking height, the order of the aromatic layers was enhanced, and the number of aromatic sheets with a larger curvature increased. The coal ultramicropores are mainly concentrated from 0.4 to 0.7 nm. Heat treatment reduces the total number of ultramicropores, but the maximum number of pores is increased. The non-six-membered ring and lattice defects lead to the bending of the fringes, the distribution of fatty structures affects the orientation of the fringes, and the relationship between the pore and molecular structure does not exist independently. After heat treatment, the aggregate structure and ultramicropore size of coal have a high correlation with the activation energy. The activation energy is closely related to the 0.6 nmultramicropores. However, the current experiment could not explain the underlying causes of these relationships. The aggregated state in coal is the macromolecular group formed between different aromatic structures, fat structures and other molecules, which is formed by the interaction of internal defects and pores in the molecular group. The structural differences at different temperatures therefore reflect the interaction of different macromolecules in coal.
We study the energy landscape of a model of a single particle on a random potential, that is, we investigate the topology of level sets of smooth random fields on
R
N
of the form
X
N
(
x
)
+
μ
2
‖
x
...‖
2
,
where
X
N
is a Gaussian process with isotropic increments. We derive asymptotic formulas for the mean number of critical points with critical values in an open set as the dimension
N
goes to infinity. In a companion paper, we provide the same analysis for the number of critical points with a given index.
In the present paper, with using diverse methods (including the SEM, the XRD, the TPO, the FTIR, and the TGA) , the authors analysed samples of the major coal seam in Dahuangshan Mining area with ...different particle sizes and with different heated temperatures (from 50 to 800 °C at regular intervals of 50 °C). The results from SEM and XRD showed that high temperature and high number of pores, fissures, and hierarchical structures in the coal samples could facilitate oxidation reactions and spontaneous combustion. A higher degree of graphitization and much greater number of aromatic microcrystalline structures facilitated spontaneous combustion. The results from TPO showed that the oxygen consumption rate of the coal samples increased exponentially with increasing temperature. The generation rates of different gases indicated that temperatures of 90 °C or 130 °C could accelerate coal oxidation. With increasing temperature, the coal oxidation rate increased, and the release of gaseous products was accelerated. The FTIR results showed that the amount of hydroxide radicals and oxygen-containing functional groups increased with the decline in particle size, indicating that a smaller particle size may facilitate the oxidation reaction and spontaneous combustion of coal. The absorbance and the functional group areas at different particle sizes were consistent with those of the heated coal samples, which decreased as the temperature rose. The results from TGA showed that the characteristic temperature T
declined with decreasing particle size. After the sample with 0.15-0.18 mm particle size was heated, its carbon content decreased, and its mineral content increased, inhibiting coal oxidation. This result also shows that the activation energy of the heated samples tended to increase at the stage of high-temperature combustion with increasing heating temperature.
Noble metal nanoparticles are promising catalysts in electrochemical reactions, while understanding the relationship between the structure and reactivity of the particles is important to achieve ...higher efficiency of electrocatalysis, and promote the development of single‐molecule electrochemistry. Electrogenerated chemiluminescence (ECL) was employed to image the catalytic oxidation of luminophore at single Au, Pt, and Au‐Pt Janus nanoparticles. Compared to the monometal nanoparticles, the Janus particle structure exhibited enhanced ECL intensity and stability, indicating better catalytic efficiency. On the basis of the experimental results and digital simulation, it was concluded that a concentration difference arose at the asymmetric bimetallic interface according to different heterogeneous electron‐transfer rate constants at Au and Pt. The fluid slip around the Janus particle enhanced local redox reactions and protected the particle surface from passivation.
Electrocatalytic oxidation of a luminophore at single Au, Pt, and Au‐Pt Janus nanoparticles was studied using electrogenerated chemiluminescence (ECL) microscopy. Compared to the monometal nanoparticles, the Janus particle structure exhibited enhanced ECL intensity and stability, indicating better catalytic efficiency.
This paper considers a hybrid-format online retailing supply chain in which a manufacturer sells products to an online retailer and an intermediary with a wholesale contract, the retailer sells them ...through the intermediary by paying a commission fee (i.e. agency selling format), and the intermediary resells products as an e-tailer (i.e. reselling format). We use a theoretical model to answer a key question: whether the intermediary has an incentive to share demand information with others, and if it shares, which strategy is most beneficial to each member? Four information-sharing models are established and the results show that the intermediary always has incentive to share information voluntarily, and the best strategy strongly depends on the channel competition intensity and proportional fee. In addition, the manufacturer (retailer) can obtain profit if the intermediary only shares information with him (her), and all members can achieve a Pareto improvement (i.e. win-win-win situation) when both the manufacturer and retailer are informed. We further examine the impact of platform cost to demonstrate the robustness of results. When manufacturer cooperates with the retailer, the intermediary always intends to share information, whereas it has no incentive to do so if the intermediary and retailer make a coalition.
High ion selectivity and permeability, as two contradictory aspects for the membrane design, highly hamper the development of osmotic energy harvesting technologies. Metal–organic frameworks (MOFs) ...with ultra‐small and high‐density pores and functional surface groups show great promise in tackling these problems. Here, we propose a facile and mild cathodic deposition method to directly prepare crack‐free porphyrin MOF membranes on a porous anodic aluminum oxide for osmotic energy harvesting. The abundant carboxyl groups of the functionalized porphyrin ligands together with the nanoporous structure endows the MOF membrane with high cation selectivity and ion permeability, thus a large output power density of 6.26 W m−2 is achieved. The photoactive porphyrin ligands further lead to an improvement of the power density to 7.74 W m−2 upon light irradiation. This work provides a promising strategy for the design of high‐performance osmotic energy harvesting systems.
A porphyrin metal–organic framework membrane has been fabricated by a facile cathodic deposition method. The high ion selectivity and permeability endow the MOF membrane with a great performance in osmotic energy harvesting, and this performance can be further improved by the photoactive porphyrin ligands upon light irradiation.
Circulating tumor DNA (ctDNA) provides a noninvasive approach to elucidate a patient's genomic landscape and actionable information. Here, we design a ctDNA-based study of over 10,000 pan-cancer ...Chinese patients. Using parallel sequencing between plasma and white blood cells, 14% of plasma cell-free DNA samples contain clonal hematopoiesis (CH) variants, for which detectability increases with age. After eliminating CH variants, ctDNA is detected in 73.5% of plasma samples, with small cell lung cancer (91.1%) and prostate cancer (87.9%) showing the highest detectability. The landscape of putative driver genes revealed by ctDNA profiling is similar to that in a tissue-based database (R
= 0.87, p < 0.001) but also shows some discrepancies, such as higher EGFR (44.8% versus 25.2%) and lower KRAS (6.8% versus 27.2%) frequencies in non-small cell lung cancer, and a higher TP53 frequency in hepatocellular carcinoma (53.1% versus 28.6%). Up to 41.2% of plasma samples harbor drug-sensitive alterations. These findings may be helpful for identifying therapeutic targets and combined treatment strategies.
The pore structure of cement pastes incorporating fly-ash was evaluated during their hydration process through gravimetry method, mercury intrusion porosimetry (MIP) and nitrogen ...adsorption/desorption (NAD) methods. The pore structure of samples is characterized by the total porosity, pore size distribution (PSD), pore internal surface area as well as characteristic pore sizes. The correlation between the hydration process and the formed pore structure is investigated. The results indicate that: (i) w/b ratios have determinant impact on all characteristics of pore structure; (ii) fly-ash replacement ratio can influence the pore structure significantly at early age but this influence becomes less important with sample age by fly-ash hydration process; (iii) the total porosity and specific surface area are well correlated with the chemical kinetics of hydration through hydration degree or the formed gel/space ratio but the critical pore size is rather independent on the chemical kinetics.
Materials with fractal structures may show distinct features of wetting. Here we report the characteristics of wetting of liquid caps on fractal surfaces in the Wenzel wetting regime. It shows that ...the relationship between the apparent and Young’s contact angles is associated with the size-matching degree or discrepancy between the liquid caps and substrate. An explicitly fractal-dimension-and size-related equation is developed to bridge over the apparent contact angle and the Young’s contact angle, and validated by the experimental results of water wetting on nanostructured fractal surfaces reported in the literature. The features of the Wenzel wetting of liquid caps on fractal surfaces are also discussed. This work enables us to understand the wetting regimes on fractal surfaces, and may pave a path for the rational uses of fractal structures to control liquid wetting.
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