Enhanced Photoelectrochemical Water Splitting and Photocatalytic Water Oxidation of Cu2O Nanocube-Loaded BiVO4 Nanocrystal Heterostructures

Wenzhong Wang,Weiwei Zhang,Shan Meng,Lujie Jia,Miao Tan,Chenchun Hao,Yujie Liang,JUN WANG,Bin Zou 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6

Reducing the fast recombination of photogenerated electron-hole pairsof semiconductor photocatalyst is very important to improve itsphotocatalysis. In this paper we fabricate Cu2O nanocube-decoratedBiVO4 nanocrystal (denoted as BiVO4@Cu2O nanocrystal@nanocube)heterostructure photocatalyst by coupling n-type BiVO4 with p-type Cu2O. The BiVO4@Cu2O nanocrystal@nanocube photocatalysts show superiorphotocatalytic activities in photoelectrochemical (PEC) activity andphotocatalytic water oxidation to BiVO4 photocatalysts under visible lightillumination. The BiVO4@Cu2O nanocrystal@nanocube heterostructureelectrode achieves the highest photocurrent density of ~ 10 μA cm−2 at 0 Vversus Ag/AgCl, 5 times higher than that of BiVO4 nanocrystal electrode (~ 2 μA cm−2). The light induced evolution rate of O2generation for BiVO4@Cu2O nanocrystal@nanocube heterostructures is as high as 150 μmol h−1100 mg cat−1, more than 3times higher than that (48 μmol h−1100 mg cat−1) of BiVO4 nanocrystals. The enhanced photocatalysis activities of theBiVO4@Cu2O nanocrystal@nanocube photocatalysts are attributed to the efficient separation of the photoexcited electron-holepairs caused by inner electronic field (IEF) of p-n junction. This study opens up new opportunities in designing photoactivematerials with highly enhanced performance for solar energy conversion.

High-Voltage Transmission Line Foreign Object and Power Component Defect Detection Based on Improved YOLOv5

Wang Shanshan,Tan Weiwei,Yang Tengfei,Zeng Liang,Hou Wenguang,Zhou Quan 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1

With the outstanding performance of deep learning in the feld of computer vision, the automatic visual detection of foreign bodies in transmission lines and electrical equipment defects by inspection robots and Unmanned Aerial Vehicles based on neural networks has become an attractive topic in smart grid. However, in practical application scenarios, small-sized target defects pose a great challenge to the detection accuracy of existing mainstream deep learning detection networks with limited perceptual felds. To solve the above problems, the paper proposes a detection model of YOLOv5 transmission line inspection image. Firstly, the key target images under diferent backgrounds and attitudes are collected and preprocessed. Specifcally, in order to improve the perception ability of networks for small-sized targets, the K-means clustering algorithm is used to optimize the size of the anchor box, which efectively improves the ftting ability of the key target features. Then, recursive gated convolution is used as the backbone network to improve the ability to extract key target features. Finally, considering the concealment of small-scale features, the space-to-depth convolution module is added to the neck network to realize down-sampling and retain all the information in the channel dimension. In addition, a feature prediction layer is added to optimize the scale of network detection, and a Simple Parameter-Free Attention Module is added to further optimize the characterization of network features. The experimental results show that the accuracy and recall of the proposed network are 96.8% and 93.3%, respectively. The average detection accuracy reaches 97.1%, which is 3.8% higher than that of YOLOv5 network, 5.2% higher than YOLOv6 and 1.0% higher than that of YOLOv7 network. The proposed method signifcantly improves the detection performance of critical targets and defects of high-voltage transmission lines.

Improvement of Fumigaclavine C Production in a Two-stage Culture of Aspergillus fumigatus with Molasses as a Cost-effective Ingredient

Yi-Xiang Zhu,WEIWEI HUAN,Ling-yun Yao,Wan-Guo Yu,Ruihua Jiao,Yan-Hua Lu,Renxiang Tan 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.6

Fumigaclavine C (FC), which is produced by Aspergillus fumigatus, is a conidiation-associated ergot alkaloid with significant medical benefits. However, its application is restricted by low yields from submerged cultures. In this study, the technical feasibility of using molasses as a cost-effective ingredient for FC production in a two-stage culture of A. fumigatus was evaluated. The results indicated that molasses supplementation significantly enhanced FC accumulation by promoting conidiation and up-regulating hydroxymethylglutaryl-CoA reductase activity. Via the optimization of the two-stage process in the presence of molasses, FC production in shake flasks reached 226.9 mg/L, which was approximately three times that in the original medium (75.9 mg/L). The use of molasses as a cost-effective ingredient for FC fermentation was also successfully reproduced in a lab-scale bioreactor system in which the maximum FC production reached 215.0 mg/L. The FC production obtained in this study is the highest ever reported. This increased efficiency will enable large-scale production of FC and extend the application of molasses as a low-cost substrate for producing other conidiation-related secondary metabolites.

Distribution of diagenetic alterations within depositional facies and sequence stratigraphic framework of fan delta and subaqueous fan sandstones: evidence from the Lower Cretaceous Bayingebi Formation, Chagan sag, China–Mongolia frontier area

Wei Wei,Xiaomin Zhu,Mingxuan Tan,Chenbingjie Wu,Dianbin Guo,Hui Su 한국지질과학협의회 2016 Geosciences Journal Vol.20 No.1

Linking siliciclastic diagenesis to sequence stratigraphy allows a better understanding of the parameters controlling the spatial and temporal distribution of diagenetic alterations. A study of the subaqueous fan and fan delta sandstones of the Bayingebi Formation, Lower Cretaceous, Chagan sag (China), reveals that the distribution of diagenetic alterations can be constrained within a sequence stratigraphic framework. Eogenetic alterations, which were encountered in the sandstones of subaqueous fan and fan delta, include: (1) replacement of detrital silicates and mud matrix by kaolinites in sandstones of the late highstand systems tract (HST) and the lowstand systems tract (LST). The formation of kaolinites is attributed to the influx of meteoric water when the base level fell and the channels migrated laterally on preexisting floodplains or channel deposits. (2) Infiltrated clays, which rim around detrital grains, mainly occur in channel sandstones of the LST due to the percolation of mud-rich surface waters. (3) Calcite I (δ18OVPDB = –20.19‰ to −3.64‰ and δ13CVPDB = –0.67‰ to –3.1‰), Calcite II (δ18OVPDB = –14‰ to –18.28‰ and δ13CVPDB = –2.2‰ to –3.60‰), dolomite (δ18OVPDB = –17.91‰ to –21.04‰ and δ13CVPDB = –0.46‰ to –1.66‰) and ankerite (δ18OVPDB = –15.02 to –20.42‰ and δ13CVPDB = –0.074 to –1.43‰), which are associated with palaeosol horizons mainly developed on top of overbank and channel sandstones of transgressive systems tract (TST) and early stage of the HST. Such extensive eogenetic calcite cements may act as potential layers for the formation of reservoir compartments for underlying sandstones. Mesogenetic alterations include: (1) abundant quartz overgrowths in the overbank sandstones of subaqueous fan in the LST and pro-fan-delta sandstones in the HST, in which early carbonate cements are lacking and grain-coats are thin. (2) Illite, chlorite and albitized feldspars, which occur in small amounts, are most common in the LST and late stage of the HST sandstones. Such cementation by calcite, dolomite, quartz overgrowths and formation of illite led to porosity and permeability deterioration during mesodiagenesis. This study revealed the importance of integration of diagenesis with sequence stratigraphy of subaqueous fan and fan delta sandstones in improving our ability to predict the spatial and temporal distribution of eogenetic alterations and their subsequent impact on mesogenetic alterations, and thus on reservoir quality modifications.