17 research outputs found
Revisiting energy efficiency and energy related CO2 emissions: Evidence from RCEP economies
Since the last four decades, energy demand has been reached to
the utmost level, which also leads to emissions and causes environmental
degradation, global warming and climate change all
over the world. In this sense, policy makers have suggested various
measures including renewable adoption and energy efficiency.
Current study aims to investigate the influence of
economic growth, energy consumption, renewable electricity output,
and energy efficiency on the energy related emissions. A
panel of 12 RCEP economies are examined covering the period
1990-2020. Since the data follows irregular path, therefore a novel
method of moment panel quantile regression is employed along
with the Granger causality test. The empirical results indicate that
economic growth and energy consumption significantly enhances
energy related emissions, where the magnitude and significance
level is found strengthening from lower to upper quantiles (Q0.25,
Q0.50, Q0.75 and Q0.90). Conversely, renewable electricity and energy
efficiency are the significant tools for lowering energy related
emissions in the region. Additionally, a unidirectional causality is
found from energy consumption and renewable electricity output
to energy related emissions. However, a feedback effect is validated
between economic growth, energy efficiency, and energy
related emissions. Based on the empirical findings, this study suggests
enhancement of renewable electricity output and adoption
of energy efficient technologies to reduce environmental degradation
and emission level
Uncertainty shocks and monetary policy: evidence from the troika of China’s economy
Growth in China’s economy is driven by the troika: consumption,
investment and export. This paper examines the effect of uncertain events such as the global financial crisis in 2008, and the
COVID-19 pandemic on the troika. Based on the construction of a
new uncertainty index of China’s economy, the relationship
between uncertainty and growth in the troika is examined by
using a TVP-VAR model. Results show that fluctuations in the
uncertainty index during the COVID-19 epidemic had the greatest
negative impact on consumption and investment at a magnitude
of 0.27, notably greater than that during the period of the global financial crisis. The negative impact on export reached 0.73,
smaller than that during the global financial crisis. Against a backdrop of the novel coronavirus epidemic, it is also found that
expansionary monetary policies can have a relatively large impact
on investment and export, reaching 1.75 and 1.57 respectively,
while short-term impact on consumption is relatively weak, averaging at 0.51
Dynamic Indoor Fingerprinting Localization based on Few-Shot Meta-Learning with CSI Images
While fingerprinting localization is favored for its effectiveness, it is
hindered by high data acquisition costs and the inaccuracy of static
database-based estimates. Addressing these issues, this letter presents an
innovative indoor localization method using a data-efficient meta-learning
algorithm. This approach, grounded in the ``Learning to Learn'' paradigm of
meta-learning, utilizes historical localization tasks to improve adaptability
and learning efficiency in dynamic indoor environments. We introduce a
task-weighted loss to enhance knowledge transfer within this framework. Our
comprehensive experiments confirm the method's robustness and superiority over
current benchmarks, achieving a notable 23.13\% average gain in Mean Euclidean
Distance, particularly effective in scenarios with limited CSI data.Comment: 5 pages,7 figure
The level effect and volatility effect of uncertainty shocks in China
Previous studies have assumed that the volatility of exogenous
shocks is constant, which can only measure the level effects of
uncertain shocks. This article introduces the time-varying volatility
model into a Dynamic Stochastic General Equilibrium (D.S.G.E.)
model and uses the third-order perturbation method to identify
and decompose the level and volatility effects of uncertainty
shocks. Based on the results of empirical research in China, the
effect of volatility shocks is different from that of level shocks: the
effect of level shocks is direct and positive, and its impact is
larger, while the effect of volatility shocks is indirect and negative,
and its impact is smaller. This article also finds that the impact of
uncertainty shocks will lead to economic stagnation, inflation, and
the stagflation effect
Response of early diagenesis to methane leakage in the inner shelf of the East China Sea
Shelf seas are experiencing a rise in shallow gas leaks, primarily methane, raising concerns due to their environmental impact. However, the effect of the leaks on early diagenesis remains poorly understood. This study analyzes sediment lithology, organic geochemistry and porewater geochemistry of two short cores collected nearby the pockmarks in the muddy inner shelf of the East China Sea. Our findings clearly demonstrate the impact of methane leakage on early diagenesis, evidenced by the shallower position of the SMTZ (sulfate-methane transition zone), higher concentrations of uranium (U), vanadium (V), and manganese (Mn) in the porewater near and above the SMTZ, and downcore decrease in Mg2+, Ca2+, and Sr2+ concentrations versus increase in Mg2+/Ca2+ and Sr2+/Ca2+ ratios. Their profile variations and the difference between two cores are determined by the intensity of methane leakage. The estimated methane diffusive flux of 619 mmol m-2 yr-1 at YEC7–2 is roughly 8.5 times that at YEC7–1 (73 mmol m-2 yr-1), consistent with a shorter distance of YEC7–2 to the pockmark with active methane leakage. A schematic model is summarized to demonstrate the response of early diagenesis processes to the increasing methane leakages in response to changing sedimentation regimes from accretion to severe erosion. This study undoubtedly improves our understanding mutual promotion effect between seafloor erosion and gas leakage, and their impact on early diagenesis processes and resultant porewater geochemical changes and authigenic mineral records
One-point extensions of nonpure piecewise-Koszul algebras(Nonpure分段Koszul代数的单点扩张)
设Λ=Λ0 ⊕Λ1 ⊕Λ2⊕…是标准分次代数,M=M1⊕M2⊕…是由M1生成的有限生成分次Λ-模,k是任意域.记为由Λ和M决定的单点扩张代数.讨论了单点扩张代数A的nonpure分段Koszul性质.特别地,给出了使得A是nonpure分段Koszul代数的充分必要条件
Intelligent Evaluation of Marine Corrosion of Q420 Steel Based on Image Recognition Method
Marine engineering materials are prone to serious corrosion damage, which affects the efficiency and reliability of marine equipment. The diversity of corrosion morphology makes it difficult to achieve the quantification and standardization of the microscopic local information on the corroded surface, which is of great significance to reveal the multi-scale corrosion mechanism. In this paper, an image intelligent recognition method for the corrosion damage of Q420 steel in seawater is established, which is based on the gray level co-occurrence matrix, binary image method and fractal model. Through the feature extraction of corrosion morphology, the quantitative analysis of corrosion morphology and the microscopic evaluation of corrosion characteristics are achieved. The image recognition data are consistent with the electrochemical result for most cases, which confirms the validity of this image intelligent recognition method. The average gray value and energy value of corrosion morphology reduces with the Cl− concentration, indicating that the corrosion damage aggravates gradually. The increasing standard deviation and entropy reflects that the randomness of the pit distribution increases. The pitting ratio increases from 20.19% to 51.64% as the Cl− concentration increases from 50% to 200% of the standard solution. However, there exists a discrepancy for high Cl− concentration because of the irregular corrosion morphology and various pit depth. The fractal dimension increases with the complexity of the corroded surface at low Cl− concentration, but the fractal dimension decreases at high Cl− concentration because the corrosion complexity is interfered by the interconnection of corrosion holes due to the accelerated pit evolution
Multi-physics analysis of the galvanic corrosion of Mg-steel couple under the influence of time-dependent anisotropic deposition film
The anisotropic deposit film formed during the galvanic corrosion can impede the mass transfer of the involved species, thereby affecting the electro-chemical behavior and the evolution of galvanic corrosion. The limitations of experimental studies in the spatial-temporal scales restrict a deeper understanding of the corrosion mechanism, which can be complemented by numerical simulation. A multi-physics coupled model is proposed in this work to systematically investigate the temporal and spatial evolution of galvanic corrosion of the Mg-steel couple with the growing anisotropic deposition layer. By utilizing the multi-physics field coupled technique, various coupled physical-chemical processes underlying the corrosion behavior are built into the model, including chemical reactions, ionic mass transfer in the bulk solution and the deposition layer, interfacial reaction, deposition of corrosion products as well as the morphological transitions caused by metal dissolution and deposition. In particular, the anisotropic deposit film is considered to be a porous layer with a porosity varying in time and space as the corrosion evolves. The predicted corrosion morphology by this model is better than the previous models. The coupled relationship between the electrochemical behavior (e.g., electrode reaction kinetics, current density, surface potential) and the physical processes (e.g., ionic transport, geometric evolution of metal surface and film interface) is revealed. The results indicate that a porous deposition layer with a denser inner layer and a loose outer layer is generated, leading to more significant inhibition of mass transfer in the inner layer than the outer layer. The anisotropism of the deposition layer results in a non-uniform conductivity distribution and a discontinuous current density distribution in the electrolyte. The current density on the electrode surface is inhibited by the deposition layer and the variation in the cathode/anode area ratio during the corrosion process. The competition between the transport process and the electrochemical reaction determines the spatial-temporal evolution of the ion concentration
The Influence of Accommodation on Retinal Peripheral Refraction Changes in Different Measurement Areas
Background. The change in refraction caused by accommodation inevitably affects the peripheral defocus state and thus may influence the effect of retinal peripheral myopic defocus measures in myopia control. This study investigated accommodation changes in different peripheral retinas under cycloplegia to help improve myopia control. Methods. Fifty-six eyes of fifty-six myopic subjects were recruited for this prospective study. The center and peripheral retina refractions were measured using multispectral refractive topography. The subjects were divided into low-to-moderate myopia group (range: −1.25 D to −6.00 D) and high myopia group (range: −6.25 D to −9.75 D) according to spherical equivalent (SE). The compound tropicamide (0.5% tropicamide and 0.5% phenylephrine) was used to relax the accommodation. The difference between cycloplegia and non-cycloplegia peripheral retinal refraction was analyzed using the t-test. The correlation between eccentricity and changes in peripheral refraction was analyzed using Pearson’s correlation analysis. Results. The manifest refraction of the retina significantly decreased with an increase in eccentricity after cycloplegia. The annular refraction difference value at 50°–53° (ARDV 50–53) showed the largest refraction decrease of 1.31 D compared with the central retinal refraction decrease of 0.84 D. The inferior quadrantal refraction difference value had the least change compared to the other quadrants. The relative peripheral refraction (RPR) changes in refraction difference value (RDV) at 15° (RDV-15), RDV-30, and RDV-45 were less than 0.15 D. When the range of annulus narrowed to 5°, the narrower annulus showed faster change with eccentricity increase in ARDV 30–35, ARDV 35–40, ARDV 40–45, ARDV 45–50, and ARDV 50–53. The RPR was highly correlated with eccentricity (R = 0.938 and P<0.001). The high myopia group had a greater hyperopic shift in the periphery than the low-to-moderate group after cycloplegia. Conclusions. Peripheral refraction showed a significant hyperopic shift after cycloplegia with an increase in eccentricity. The RPR became more hyperopic than the central refraction. The high myopia group showed more hyperopic shifts in the peripheral region. Accommodation should be taken into consideration in peripheral defocus treatment
Nanoengineered Ultralight Organic Cathode Based on Aromatic Carbonyl Compound/Graphene Aerogel for Green Lithium and Sodium Ion Batteries
Organic
electroactive materials are promising alternatives to traditional
inorganic ones in green organic batteries. However, their practical
use is greatly hindered by the intrinsic electrical insulation and
the high solubility in electrolyte. Here, we propose an effective
strategy to prepare nanoengineered ultralight materials based on organic
electroactive material/graphene aerogel in which aromatic carbonyl
compounds are confined in the three-dimensional hybrid architecture.
This special structure has been confirmed by SEM, TEM, FT-IR, XRD,
Raman spectra, and N<sub>2</sub> adsorption/desorption isotherms.
Electrochemical investigation further demonstrates that the obtained
composite shows a high storage capacity of Li<sup>+</sup>/Na<sup>+</sup> ions, long cycling life, and good rate capability as cathode materials
for Li- and Na-ion batteries (LIBs and SIBs). This enhanced property
is attributed to the special structure that significantly improves
the conductivity and effectively prohibits the dissolution of active
material but also affords good Li<sup>+</sup>/Na<sup>+</sup> ions
accessibility to the organic electroactive materials and shortens
the Li<sup>+</sup>/Na<sup>+</sup> ions diffusion length. This work
can be further extended to prepare various electrodes based on organic
materials for energy storage application