Clean energy production and saving play vital impacts on the sustainability of the global community. Herein, high‐performance semitransparent organic solar cells (ST‐OSCs) with excellent features of ...power generation, being see‐through, and infrared reflection of heat dissipation, with promising perspectives for building‐integrated photovoltaics (BIPVs) are reported. To simultaneously improve average visible transmittance (AVT) and power conversion efficiency (PCE), formally in a trade‐off relationship, of ST‐OSCs, new ternary blends with alloy‐like near‐infrared (NIR) acceptors are employed, which are effective to improve device efficiency while maintaining visible absorption unchanged, resulting in PCEs of 16.8% for opaque devices and 13.1% for semitransparent OSCs (AVT of 22.4% and infrared photon radiation rejection (IRR) of 77%). Further, multifunctional ST‐OSCs are realized via introducing simple, yet effective photonic reflectors, together with optical simulation, leading to not only perfect fitting of the visible transmittance peak (555 nm) to the photopic response of the human eye but also an excellent IRR of 90% (780–2500 nm), along with 23% AVT and over 12% PCE. This is thought to be the best‐performing multifunctional ST‐OSC with promising prospects as BIPVs in terms of power generation, heat dissipation, and being see‐through.
High‐performance semitransparent organic solar cells are achieved through combined design efforts on the formulation of near‐infrared ternary blends and optical control over photonic reflectors, which exhibit excellent features of power generation, they being see‐through, and infrared reflection.
Over the past decade, video anomaly detection has been explored with remarkable results. However, research on methodologies suitable for online performance is still very limited. In this paper, we ...present an online framework for video anomaly detection. The key aspect of our framework is a compact set of highly descriptive features, which is extracted from a novel cell structure that helps to define support regions in a coarse-to-fine fashion. Based on the scene's activity, only a limited number of support regions are processed, thus limiting the size of the feature set. Specifically, we use foreground occupancy and optical flow features. The framework uses an inference mechanism that evaluates the compact feature set via Gaussian Mixture Models, Markov Chains, and Bag-of-Words in order to detect abnormal events. Our framework also considers the joint response of the models in the local spatio-temporal neighborhood to increase detection accuracy. We test our framework on popular existing data sets and on a new data set comprising a wide variety of realistic videos captured by surveillance cameras. This particular data set includes surveillance videos depicting criminal activities, car accidents, and other dangerous situations. Evaluation results show that our framework outperforms other online methods and attains a very competitive detection performance compared with state-of-the-art non-online methods.
Increasing visible light absorption of classic wide‐bandgap photocatalysts like TiO2 has long been pursued in order to promote solar energy conversion. Modulating the composition and/or stoichiometry ...of these photocatalysts is essential to narrow their bandgap for a strong visible‐light absorption band. However, the bands obtained so far normally suffer from a low absorbance and/or narrow range. Herein, in contrast to the common tail‐like absorption band in hydrogen‐free oxygen‐deficient TiO2, an unusual strong absorption band spanning the full spectrum of visible light is achieved in anatase TiO2 by intentionally introducing atomic hydrogen‐mediated oxygen vacancies. Combining experimental characterizations with theoretical calculations reveals the excitation of a new subvalence band associated with atomic hydrogen filled oxygen vacancies as the origin of such band, which subsequently leads to active photo‐electrochemical water oxidation under visible light. These findings could provide a powerful way of tailoring wide‐bandgap semiconductors to fully capture solar light.
In contrast to the common tail‐like absorption band in hydrogen‐free oxygen‐deficient TiO2, an unusual strong absorption band spanning the full spectrum of visible light is achieved in red anatase TiO2 by intentionally introducing atomic hydrogen‐mediated oxygen vacancies that subsequently lead to active photo‐electrochemical water oxidation under visible light.
•For the first time a LSTM-ED model is proposed to model multi-step-ahead flood forecasting.•Sequence-to-sequence learning converts an input sequence into an output sequence.•LSTM encoder-decoder ...models tackle the challenging sequence-to-sequence prediction.•The LSTM-ED model reduced RMSE by 3% (T + 1) to 38% (T + 6) as compared to the benchmark.•The LSTM-ED model can provide reliable and accurate multi-step-ahead flood forecasts.
Operational flood control systems depend on reliable and accurate forecasts with a suitable lead time to take necessary actions against flooding. This study proposed a Long Short-Term Memory based Encoder-Decoder (LSTM-ED) model for multi-step-ahead flood forecasting for the first time. The Shihmen Reservoir catchment in Taiwan constituted the case study. A total of 12,216 hourly hydrological data collected from 23 typhoon events were allocated into three datasets for model training, validation, and testing. The input sequence of the model contained hourly reservoir inflows and rainfall data (traced back to the previous 8 h) of ten gauge stations, and the output sequence stepped into 1- up to 6-hour-ahead reservoir inflow forecasts. A feed forward neural network-based Encoder-Decoder (FFNN-ED) model was established for comparison purposes. This study conducted model training a number of times with various initial weights to evaluate the accuracy, stability, and reliability of the constructed FFNN-ED and LSTM-ED models. The results demonstrated that both models, in general, could provide suitable multi-step ahead forecasts, and the proposed LSTM-ED model not only could effectively mimic the long-term dependence between rainfall and runoff sequences but also could make more reliable and accurate flood forecasts than the FFNN-ED model. Concerning the time delay between the time horizons of model inputs (rainfall) and model outputs (runoff), the impact assessment of this time-delay on model performance indicated that the LSTM-ED model achieved similar forecast performance when fed with antecedent rainfall either at a shorter horizon of 4 h in the past (T − 4) or at horizons longer than 7 h in the past (>T − 7). We conclude that the proposed LSTM-ED that translates and links the rainfall sequence with the runoff sequence can improve the reliability of flood forecasting and increase the interpretability of model internals.
Amorphous carbon nitride (ACN) with a bandgap of 1.90 eV shows an order of magnitude higher photocatalytic activity in hydrogen evolution under visible light than partially crystalline graphitic ...carbon nitride with a bandgap of 2.82 eV. ACN is photocatalytically active under visible light at a wavelength beyond 600 nm.
Street dust is repeatedly raised by the wind as a secondary suspension, helping heavy metals therein to enter the human body through the respiratory system, harming human health. A detailed ...investigation was conducted to determine levels and sources of Cd (cadmium), Cr (chromium), Cu (copper), Pb (lead), Zn (zinc), Ni (nick), and Hg (mercury) contamination in street dust from Shijiazhuang, China. The average concentrations of these metals were: Cd, 1.86 mg·kg
; Cr, 131.7 mg·kg
; Ni, 40.99 mg·kg
; Cu, 91.06 mg·kg
; Pb, 154.78 mg·kg
, Hg, 0.29 mg·kg
; and Zn, 496.17 mg·kg
-all of which were greater than the local soil reference values. The concentrations of the heavy metals were mapped for the three Shijiazhuang ring roads, with the results showing significant differences between each ring. Application of enrichment factors and geoaccumulation indexes showed that there was significant enrichment and accumulation of Cd, Pb, Zn, and Hg. Multivariate statistical analyses showed that Cd, Pb, Zn, and Hg levels were mainly controlled by human activities, while Cr, Ni, and Cu levels were associated with natural sources. Absolute principal component scores with multiple linear regression (APCS-MLR) were applied to facilitate source apportionment. The results showed that the mixed (traffic and industry) group contributed 53.55%, 59.7%, and 62.25% of the Cd, Pb, and Zn concentration, respectively, while the natural sources group contributed 58.01%, 65.09%, and 66.91% of the Cu, Ni, and Cr concentration, respectively. The burning coal group was found to be responsible for 63.38% of the Hg present in the samples. These results provide a useful theoretical basis for Shijiazhuang authorities to address heavy metal pollution management.
Photoassisted electrochemical reaction is regarded as an effective approach to reduce the overpotential of lithium–oxygen (Li–O2) batteries. However, the achievement of both broadband absorption and ...long term battery cycling stability are still a formidable challenge. Herein, an oxygen vacancy‐mediated fast kinetics for a photoassisted Li–O2 system is developed with a silver/bismuth molybdate (Ag/Bi2MoO6) hybrid cathode. The cathode can offer both double advantages for light absorption covering UV to visible region and excellent electrochemical activity for O2. Upon discharging, the photoexcited electrons from Ag nanoplate based on the localized surface plasmon resonance (LSPR) are injected into the oxygen vacancy in Bi2MoO6. The fast oxygen reaction kinetics generate the amorphous Li2O2, and the discharge plateau is improved to 3.05 V. Upon charging, the photoexcited holes are capable to decompose amorphous Li2O2 promptly, yielding a very low charge plateau of 3.25 V. A first cycle round‐trip efficiency is 93.8% and retention of 70% over 500 h, which is the longest cycle life ever reported in photoassisted Li–O2 batteries. This work offers a general and reliable strategy for boosting the electrochemical kinetics by tailoring the crystalline of Li2O2 with wide‐band light.
A facile oxygen vacancy‐mediated fast kinetics for an ultrawide band photoassisted Li–O2 system is developed. The bifunctional Ag/Bi2MoO6 cathode is favorable to promoting the oxygen reduction reaction and oxygen evolution reaction kinetics due to the discharge products is amorphous Li2O2. The reaction mechanism is revealed by in situ X‐ray diffraction and Raman spectroscopy.
A novel ladder‐type donor (IDTT) is developed by substituting the two outward thiophenes of the IDT donor with two thieno3,2‐bthiophenes. The polymer derived from this donor possesses longer ...effective conjugation and better planarity, which improves electron delocalization along the polymer backbone and charge mobility. The polymer solar cell device using PIDTT‐DFBT shows a high power conversion efficiency of 7.03% with a large open‐circuit voltage of 0.95 V without using any additives or post‐solvent/thermal annealing processes.
Whole exome sequencing has been increasingly used in human disease studies. Prioritization based on appropriate functional annotations has been used as an indispensable step to select candidate ...variants. Here we present the latest updates to dbNSFP (version 4.1), a database designed to facilitate this step by providing deleteriousness prediction and functional annotation for all potential nonsynonymous and splice-site SNVs (a total of 84,013,093) in the human genome. The current version compiled 36 deleteriousness prediction scores, including 12 transcript-specific scores, and other variant and gene-level functional annotations. The database is available at http://database.liulab.science/dbNSFP with a downloadable version and a web-service.
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