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Abstract Accurately forecasting regional distributed photovoltaic (DPV) power is crucial in mitigating the negative impact of high DPV penetration on the reliability and resilience of the distribution network. However, most of the current photovoltaic power forecasting methods suffer from two key problems: (1) ignoring the asymmetric influence relationship among DPV sites; (2) lack of consideration of dynamic spatiotemporal correlation among DPV sites. As a result, these methods are unable to fully adapt to the characteristics of DPV, making it challenging to directly apply the existing forecasting methods to improve the accuracy of DPV power forecasting. To conquer this limitation, a dynamic directed Graph Convolution Neural Network (DDGCN) is applied to regional DPV ultra‐short‐term power forecasting. Unlike the conventional Graph Convolution Neural Network (GCN) based forecasting methods, the proposed method improves GCN to process the directed graph. On this basis, to capture the dynamic and directed adjacency relationship among graph nodes, a temporal attention mechanism is proposed and combined with the directed GCN model. In this way, the dynamic and asymmetric/directed relationships among DPV sites can be taken into account. It is worth noting that the DPVs’ adjacency relationship can be constructed without any prior knowledge by end‐to‐end model training. The simulation experiment proves that the prediction accuracy can be further improved by taking into account the dynamic directed relationship among the sites via a real DPV power dataset.

Abstract In this paper, a wideband transmission unit cell is proposed for programmable metasurfaces operating in the Ka-band. The unit cell features a compact period of only 2.91 mm, corresponding to 0.34 λ 0 at the center frequency of 35 GHz. A receiving layer, consisting of a patch loaded with two PIN diodes, is utilized to achieve 1-bit phase modulation, while a U-shaped patch serves as the transmitting layer to enable selection of linear polarization hold or conversion. Based on the multi-resonance principle, the proposed unit cell exhibits broadband behavior, as demonstrated by simulation results under periodic boundary conditions, which indicate a 3 dB transmission bandwidth of 29.4–40 GHz (30.5%). Two unit cells were fabricated and tested in a standard waveguide, with the minimum insertion loss of the two states tested being 1.2 dB and 3 dB bandwidths of 30.1–31.2 GHz and 33.5–38.5 GHz, respectively. The maximum 180° phase error is 10°, indicating the high quality of the proposed unit cell.

Creating porous structures and gradient structures are two commonly used design strategies for terahertz (THz) absorption enhancement. However, the synergistic effect of porous structure and gradient structure on THz absorption still remains less explored. Here, we took an almost non-conductive porous carbon foam as raw material, and fabricated an integrated gradient porous carbon foam (PCF) by microwave selective sintering. The experimental results show that the synergistic effect of the porous and gradient structures resulted in a 140% improvement in THz absorption performance. Specifically, an excellent average absorption intensity of −38.8 dB (absorptivity is about 99.99%) is obtained in the frequency range from 0.5 to 4.0 THz. COMSOL simulation and transmission line model were applied to explore the formation mechanism and the gradient loss capabilities of gradient structure. This work not only reveals the synergistic enhancement mechanism of porous and gradient structures for the THz absorption, but also provides new insights into the design of high-performance THz absorbers in the future.

Informal development, as a unique phenomenon that has become widespread in China’s urbanization process in recent years, has continued to attract the attention of both the government and academia. Existing studies focus on urban village redevelopment strategies, and little research has been conducted on informal development in urban villages under the land property approach. In particular, research needs to further explore what impact China’s collective land property rights have had on informality in urban villages. This study mainly adopts a qualitative research method, including field observation and in-depth interviews. The research was conducted in urban villages in Guangzhou. The study finds that land property rights have an important impact on urbanization and property rights arrangements have an important impact on resource allocation efficiency. Due to the ambiguity of collective land property rights in China, informal development in urban villages is the result of the collective action of villagers, government, and enterprises under the stimulation of economic development. The interaction of the stakeholders has promoted the rapid development of informal housing in urban villages.

Abstract Background It is worrisome that several pollutants can enhance the abundance of antibiotic resistance genes (ARGs) in the environment, including agricultural fungicides. As an important bioindicator for environmental risk assessment, earthworm is still a neglected focus that the effects of the fungicide carbendazim (CBD) residues on the gut microbiome and resistome are largely unknown. In this study, Eisenia fetida was selected to investigate the effects of CBD in the soil-earthworm systems using shotgun metagenomics and qPCR methods. Results CBD could significantly perturb bacterial community and enrich specific bacteria mainly belonging to the phylum Actinobacteria. More importantly, CBD could serve as a co-selective agent to elevate the abundance and diversity of ARGs, particularly for some specific types (e.g., multidrug, glycopeptide, tetracycline, and rifamycin resistance genes) in the earthworm gut. Additionally, host tracking analysis suggested that ARGs were mainly carried in some genera of the phyla Actinobacteria and Proteobacteria. Meanwhile, the level of ARGs was positively relevant to the abundance of mobile genetic elements (MGEs) and some representative co-occurrence patterns of ARGs and MGEs (e.g., cmx-transposase and sul1-integrase) were further found on the metagenome-assembled contigs in the CBD treatments. Conclusions It can be concluded that the enhancement effect of CBD on the resistome in the earthworm gut may be attributed to its stress on the gut microbiome and facilitation on the ARGs dissemination mediated by MGEs, which may provide a novel insight into the neglected ecotoxicological risk of the widely used agrochemicals on the gut resistome of earthworm dwelling in soil. Video abstract Graphical Abstract

Wheel flats are amongst the most common local surface defect in railway wheels, which can result in repetitive high wheel–rail contact forces and thus lead to rapid deterioration and possible failure of wheels and rails if not detected at an early stage. The timely and accurate detection of wheel flats is of great significance to ensure the safety of train operation and reduce maintenance costs. In recent years, with the increase of train speed and load capacity, wheel flat detection is facing greater challenges. This paper focuses on the review of wheel flat detection techniques and flat signal processing methods based on wayside deployment in recent years. Commonly used wheel flat detection methods, including sound-based methods, image-based methods, and stress-based methods are introduced and summarized. The advantages and disadvantages of these methods are discussed and concluded. In addition, the flat signal processing methods corresponding to different wheel flat detection techniques are also summarized and discussed. According to the review, we believe that the development direction of the wheel flat detection system is gradually moving towards device simplification, multi-sensor fusion, high algorithm accuracy, and operational intelligence. With continuous development of machine learning algorithms and constant perfection of railway databases, wheel flat detection based on machine learning algorithms will be the development trend in the future.

Microwave atmospheric pressure plasma jets continue to evolve with the growth of atmospheric plasma’s applications in sterilization, material modification, and cancer treatment. In this article, continuous and modulated microwave plasma filaments were produced by a hand-held microwave plasma jet, and then they were compared in plasma length, electron excitation temperature, and emission spectrum. The electron excitation temperature was measured by the emission spectroscopy diagnostic method, and the regularities of the compared parameters’ change were studied by varying duty cycles and periods of the modulating signal. The results prove that the modulated microwave can generate stable plasma filaments directly in the air without protective tubes, and it is different from the continuous microwave plasma in all compared parameters. Besides, stable dendritic tearing of plasma filaments was observed. These results imply that modulated microwave and continuous microwave plasma filaments cannot be regarded as the same, the changing manner and the reaction on the surface of the medium may be completely different even if they are the same in the ambient air in most cases. These results are helpful for the controlling and understanding of microwave plasma, and the stable tearing could be used to expand the treated area of a single plasma jet.

In the advanced technology nodes, process parameter variations are increasingly resulting in unpredictable device behavior. The issue is even aggravated by low power requirements which stretches the transistor operation into near-threshold regime. Despite device simulation gives precise results, it is time-consuming for static timing analysis and dynamic timing analysis. In this paper, we propose VASTA, a statistical timing analysis tool based on the variation-aware standard cell library. The tool efficiently supports statistical static timing analysis (SSTA) and statistical dynamic timing analysis (SDTA). The standard cell library models delay under operating environment effects by using quadratic regressions and multivariate adaptive regression splines. VASTA works on industry formats (.v and.sdc) and is designed to run in parallel during both SSTA and SDTA. The statistical cell library is built and verified using SMIC 40 nm and 28 nm PDK. The mean and standard deviation errors of cell delay models are 2.77% and 1.68% compared with SPICE simulation results under 10k Monte Carlo samples. The SSTA and SDTA are tested with ISCAS85, ISCAS89, and EPFL benchmark suites. The average mean and standard deviation errors of SSTA are 4.01% and 2.03%, which are similar to SDTA. Meanwhile, our SDTA is 17.7 times faster than traditional corner-based dynamic timing analysis which relies on generating .vcd cell activity files.

In this paper, a coaxial electrostatic wiggler with corrugated inner and outer walls is investigated theoretically. The field distributions in this wiggler correspond to the special solution of a Laplace equation in a cylindrical coordinate system with two sinusoidal ripple boundaries. Through numerical analysis and comparison to the coaxial electrostatic wiggler with a corrugated outer wall, the results indicate that in a coaxial electrostatic wiggler with corrugated inner and outer walls, electric field undulation can be enhanced. The particle-in-cell simulation further demonstrates that the electrons can be modulated deeply.

A dual-frequency plasma source has many advantages in applications. In this paper, a dual-frequency microwave plasma source is presented. This microwave plasma source is based on a coaxial transmission line without the resonator, and it can be operated in a wide band frequency region. Two microwaves are inputted from two ports into the plasma reactor: one is used firstly to excite the plasma and the other one is used to adjust plasma characteristics. Based on the COMSOL Multiphysics simulation, the experiment is carried out. In the experimental investigation, the plasma electron density and electron temperature can be controlled, respectively, by feeding in different frequencies from the second port, causing the particles at different energy levels to present different frequencies. This exploratory research improves the operation frequency of dual-frequency microwave plasma sources from RF to microwave.

Biodegradation is an important route for the removal of sulfamethazine (SMZ), one of the most commonly used sulfonamide antibiotics, in the environment. However, little information is known about the kinetics, products, and pathways of SMZ biodegradation owing to the complexity of its enzyme-based biotransformation processes. In this study, the SMZ-degrading strain A01 belonging to the genus Paenarthrobacter was isolated from SMZ-enriched activated sludge reactors. The bacterial cells were rod-shaped with transient branches 2.50–4.00 μm in length with most forming in a V-shaped arrangement. The genome size of Paenarthrobacter sp. A01 had a total length of 4,885,005 bp with a GC content of 63.5%, and it contained 104 contigs and 55 RNAs. The effects of pH, temperature, initial substrate concentration and additional carbon source on the biodegradation of SMZ were investigated. The results indicated that pH 6.0–7.8, 25 °C and the addition of 0.2 g/L sodium acetate favored the biodegradation, whereas a high concentration of SMZ, 500 mg/L, had an inhibitory effect. The biodegradation kinetics with SMZ as the sole carbon source or 0.2 g/L sodium acetate as the co-substrate fit the modified Gompertz model well with a correlation coefficient (R2) of 0.99. Three biodegradation pathways were proposed involving nine biodegradation products, among which C6H9N3O2S and C12H12N2 were two novel biodegradation products that have not been reported previously. Approximately 90.7% of SMZ was transformed to 2-amino-4, 6-dimethylpyrimidine. Furthermore, sad genes responsible for catabolizing sulfonamides were characterized in A01 with high similarities of 96.0%–100.0%. This study will fill the knowledge gap in the biodegradation of this ubiquitous micropollutant in the aquatic environment. Keywords: Sulfamethazine, Biodegradation, Paenarthrobacter, Pathways, sad genes

In order to more effectively control NO emissions in coal-fired flue gas, the denitration reaction is carried out with simulated industrial boiler flue gas in a fixed bed reactor. The influence of char types, reaction conditions, the composition of flue gas and other factors on the conversion rate of NO are discussed. The result shows that the industrial semi-coke is the most suitable experimental coal in the three coals studied, and the industrial semi-coke particle size of 0.6 ~ 10 mm is relatively suitable; The conversion rate of NO increases gradually with the increase of temperature, and when the reaction temperature is 700 ℃ and the space velocity is 10 000 h-1, the conversion rate of NO can reach 99%; the conversion rate of NO decreases gradually as airspeed increases, but the airspeed change has no effect on the conversion rate of NO at 700 ℃; under anaerobic conditions,the change of NO concentration has no effect on the conversion rate of NO; at the same temperature, NO conversion rate is higher at the presence of oxygen compared with that at anaerobic situation, and the conversion rate of NO is the highest when O2 concentration is 4%; under aerobic conditions, the concentration change of SO2 and CO2 has no effect on the conversion rate of NO.

The Langmuir probe is a feasible method to measure plasma parameters. However, as the reaction progresses in the discharged plasma, the contamination would be attached to the probe surface and lead to a higher incorrect electron temperature. Then, the electron density cannot be obtained. This paper reports a simple approach to combining the Langmuir probe and the optical emission spectrometry (OES), which can be used to obtain the electron temperature to solve this problem. Even the Langmuir probe is contaminative, the probe current–voltage (I–V) curve with the OES spectra also gives the approximate electron temperature and density. A homemade coaxial line microwave plasma source driven by a 2.45 GHz magnetron was adopted to verify this mothed, and the electron temperature and density in different pressure (40–80 Pa) and microwave power (400–800 W) were measured to verify that it is feasible.

Background While having the largest population of smokers in the world, China is among countries with the lowest percentage of male smokers who have an intention to quit. Smoking rationalization is negatively associated with quit intention in developed countries. Our previous study has showed smoking rationalization is common among Chinese male smokers and some beliefs of smoking rationalization seem to be peculiar to China. Whether the association is generalizable to Chinese smokers remains unknown. This study aims to examine the association between smoking rationalization and quit intention among a sample of male Chinese smokers. Methods A cross-sectional survey was conducted among male smokers in China in 2013. Smoking rationalization was assessed through a newly developed Chinese rationalizations scale (including 26 items under six subscales, smoking functional beliefs, risk generalization beliefs, social acceptability beliefs, safe smoking beliefs, self-exempting beliefs and quitting is harmful beliefs). Items in the scale were rated on a 5-likert scale (1 = totally disagree to 5 = totally agree). Multivariable logistic regression was performed to examine the relationship between rationalization and intention to quit, adjusted for sociodemographic variables and smoking-related variables. Results A total of 3710 participants were included in the analyses. Smoking rationalization was prevalent (mean score 3.32). With 1 point increase in total rationalization scale, the odds for smokers intention to quit in the next 6 months decreased 48% (OR=0.52, 95%CI: 0.44-0.61; p< 0.001). Separate logistic regressions for six subscale of rationalization showed consistent associations with intention to quit (all p-values < 0.001). Particularly the “social acceptability beliefs” was the strongest predictor (OR=0.62, 95%CI: 0.55-0.71; p< 0.001). Conclusions Smoking rationalization beliefs could be important barriers for male Chinese smokers to develop quit intention. Some beliefs have stronger association with quit intention than others. Tackling rationalization beliefs endorsed by smokers is a potential strategy for smoking cessation intervention.

In this paper, a nonlinear theoretical simulation method based on a 1-D electron ring model for a new extended interaction structure-the radial extended interaction oscillator (R-EIO)-working in the fundamental mode is presented. The R-EIO has a compact structure and good heat dissipation characteristics. Furthermore, because of a significant increase in the electron injection channel area, the R-EIO has the potential for higher power operation using the same current density condition as a traditional EIO structure, giving it great research value. This paper presents an example of predicted R-EIO performance based on the results of nonlinear theoretical simulation and particle-in-cell (PIC) code simulation. At a voltage and current of 3 kV and 8.48 A, respectively, the theoretical simulations predict that the as designed R-EIO could generate 1.8 kW at 12.2104 GHz, while the PIC simulation predict 1.7 kW at 12.5 GHz. Similar results could be obtained from the nonlinear theoretical simulation, which cost less than 5 min, while about 50 h for PIC code simulation in the same computer condition.

A coaxial line with periodically tapered inner rode corrugated ripples is introduced to act as a distributed Bragg reflector to increase output microwave power of relativistic diffraction generator (RDG). The RDG device consists of an overmoded cross-section, two-sectional disk-loaded cylindrical slow-wave structure (SWS), and coaxial reflector is placed upstream at the first SWS section. The RDG device with tapered Bragg reflector is investigated by full three-dimensional Particle-in-Cell (PIC) simulations and experiments in this paper. The structural parameters of the reflector are optimized for favorable characteristic of mode selection and frequency response. It is found that oscillation modes varied at different magnetic field magnitude. The measured radiation power at 29∼31 GHz is over 300 MW for TM01 mode and over 700 MW for TM11 mode. Results show that the reflector has a great impact on performance of the device. Operating at proper conditions, the radiation power is remarkably enhanced.

In this research, we investigated using unmanned aerial vehicle (UAV) photographic technology to prevent the further expansion of unauthorized construction and thereby reduce postdisaster losses. First, UAV dynamic aerial photography was used to obtain dynamic digital surface model (DSM) data and elevation changes of 2−8 m as the initial sieve target. Then, two periods of dynamic orthophoto images were superimposed for human−computer interaction interpretation, so we could quickly distinguish buildings undergoing expansion, new construction, or demolition. At the same time, mobile geographic information system (GIS) software was used to survey the field, and the information gathered was developed to support unauthorized construction detection. Finally, aerial images, interpretation results, and ground survey information were integrated and released on WebGIS to build a regulatory platform that can achieve accurate management and effectively prevent violations.

This study developed a web-based open-source framework based on the Soil and Water Assessment Tool (SWAT), named WOF-SWAT (web-based open-source framework for SWAT), to investigate individual and combined impacts of climate change, land use change, and point-source pollutants on watershed-scale hydrological and chemical processes. The architecture, workflows, interfaces, and key processes of WOF-SWAT are described and discussed. Using a previously developed well-calibrated hydrological model of the Jinjiang River basin, four scenarios were simulated in WOF-SWAT and other traditional desktop-based tools (i.e., ArcSWAT and SWAT-CUP) to examine the credibility, efficiency, and functionality of WOF-SWAT. The results show that, in combination with a well-calibrated watershed model, WOF-SWAT is sufficiently sound and reasonable to investigate individual and combined impacts of climate change, land use change, and point-source pollutants. We thus conclude that WOF-SWAT can be used as a substitute for other tools to carry out similar tasks in a web-based environment while providing more user-friendly interfaces, accessibility, and efficiency. We also discuss ongoing and possible future efforts to develop WOF-SWAT into a fully-fledged watershed research and management framework.

BACKGROUND: The complex characteristics and unclear biological fate of biomacromolecules (BMM), including colloidal and soluble microbial products (SMP), extracellular polymeric substances (EPS) and membrane surface foulants (MSF), are crucial factors that limit our understanding of membrane fouling in membrane bioreactors (MBRs). FINDINGS: In this study, the microbial transformation of BMM was investigated in a lab-scale MBR by well-controlled bioassay tests. The results of experimental measurements and mathematical modeling show that SMP, EPS, and MSF had different biodegradation behaviors and kinetic models. Based on the multi-exponential G models, SMP were mainly composed of slowly biodegradable polysaccharides (PS), proteins (PN), and non-biodegradable humic substances (HS). In contrast, EPS contained a large number of readily biodegradable PN, slowly biodegradable PS and HS. MSF were dominated by slowly biodegradable PS, which had a degradation rate constant similar to that of SMP-PS, while degradation behaviors of MSF-PN and MSF-HS were much more similar to those of EPS-PN and EPS-HS, respectively. In addition, the large-molecular weight (MW) compounds (>100 kDa) in BMM were found to have a faster microbial transformation rate compared to the small-MW compounds (