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Elevated Temperature Properties of Bamboo Shaving Reinforced Geopolymer Composites

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Journal of Renewable Materials 2023年第1期11卷 27-40页

作者： Xinli zhang jiayu zhang Zuhua zhang Yiqiang Wu Yingfeng Zuo College of Materials Science and Engineering Central South University of Forestry and TechnologyChangsha410004China College of Civil Engineering Hunan UniversityChangsha410082China

Geopolymer is a new alternative cement binder to produce *** the present study,a novel geopolymer composites containing bamboo shaving(0–2 wt.%)were fabricated and exposed to the temperatures of 200℃,400℃,600℃and 800℃.Physical properties,micro-structure,and mechanical strengths of the geopolymer composites were evaluated before and after heating in order to understand their thermal properties,which are essential for the use as building *** the temperature rises,the drying shrinkage and apparent porosity of the composites increase,while the compressive and bending strengths *** the temperature range of 200℃–800℃,the residual compressive strength rates of the geopolymer composite containning 2 wt.%bamboo shaving were respective 73.8%,61.47%,56.16%,and 29.56%,meanwhile,the residual flexural strength rates were respective 46.69%,8.68%,2.52%,and 2.33%.Correspondingly,the residual compressive strength rates of pure geopolymer were respective 72.81%,61.99%,54.55%,and 14.64%;the residual flexural strength rates were 48.87%,5.69%,3.22%,and 2.47%,*** electron microscope(SEM),optical microscope,and X-ray diffractometry(XRD)were applied to find the microscopic *** strength loss in the geopolymer composites was mainly because of the thermal degradation of bamboo shaving and shrinkage of geopolymer *** shaving has great potential as reinforcer in developing low-cost geopolymer composites and may be used for applications up to 400℃.

关键词： Geopolymer composites bamboo shaving mechanical properties high temperature microstructure

Unveiling the protective role of biofilm formation on the photoaging of microplastics

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Science China(Technological Sciences) 2024年第10期67卷 3067-3078页

作者： zhang HaiYu LIU Peng zhang jiayu DAI JiaMin zhang XinRui zhang ZiXuan JIA HanZhong Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China Ministry of AgricultureCollege of Natural Resources and EnvironmentNorthwest A&F UniversityYangling 712100China Key Laboratory of Organic Compound Pollution Control Engineering School of Environmental and Chemical EngineeringShanghai UniversityShanghai 200444China

In natural water,microplastics(MPs)inevitably undergo microbial colonization to form biofilm,while the effect of biofilm formation on the photoaging of MPs remains *** study systematically investigated the photoaging behavior of disposable box-derived polypropylene(PPMPs)and polystyrene(PSMPs)mediated by formed biofilm in *** incubating in Weihe water samples for 105 d,the biofilm was validated to form in PPMPs and PSMPs,with higher formation in *** particular,biofilm formation inhibited the photoaging of PPMPs and PSMPs,with an 11.1%and 50.6%decrease in photooxidation compared to their virgin counterparts after 20 d of ultraviolet(UV)***,the photoaging route of MPs such as the reaction priority of functional groups(e.g.,C–H,C=O,and benzene ring)was altered,indicating the important role of biofilm formation in the photoaging process of *** protective effect of the biofilm was mainly caused by the role of optical light filters that absorbed UV energy by sacrificing ***,as the main attacker on MPs,the production of reactive oxygen species(ROS,mainly^(1)O_(2)and·OH)was inhibited by biofilm,which was mainly responsible for the decreased photoaging of *** study revealed the important role of biofilm in the photoaging process of MPs and suggested a higher resistance of(micro)plastics in natural water than that in the laboratory using pure MPs,which contributed to a deeper understanding of the environmental fate and pollution of MPs.

关键词： microplastics biofilm photoaging physical shielding reactive oxygen species

Surveillance Video Key Frame Extraction Based on Center Offset

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Computers, Materials & Continua 2021年第9期68卷 4175-4190页

作者： Yunzuo zhang Shasha zhang Yi Li jiayu zhang Zhaoquan Cai Shui Lam School of Information Science and Technology Shijiazhuang Tiedao UniversityShijiazhuang050043 China 2Department of Computer Science and Engineering Huizhou UniversityHuizhou516007 China 3College of Engineering California State UniversityLong BeachCA90185USA

With the explosive growth of surveillance video data,browsing videos quickly and effectively has become an urgent *** key frame extraction has received widespread attention as an effective ***,accurately capturing the local motion state changes of moving objects in the video is still challenging in key frame *** target center offset can reflect the change of its motion *** observation proposed a novel key frame extraction method based on moving objects center offset in this *** proposed method utilizes the center offset to obtain the global and local motion state information of moving objects,and meanwhile,selects the video frame where the center offset curve changes suddenly as the key *** processing effectively overcomes the inaccuracy of traditional key frame extraction ***,extracting the center point of each ***,calculating the center point offset of each frame and forming the center offset curve by connecting the center offset of each ***,extracting candidate key frames and optimizing them to generate final key *** experimental results demonstrate that the proposed method outperforms contrast methods to capturing the local motion state changes of moving objects.

关键词： Center offset local motion key frame extraction moving object detection

Spaceflight and simulated microgravity suppresses macrophage development via altered RAS/ERK/NFκB and metabolic pathways

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Cellular & Molecular Immunology 2021年第6期18卷 1489-1502页

作者： Lu Shi Hongling Tian Peng Wang Ling Li Zhaoqi zhang jiayu zhang Yong Zhao State Key Laboratory of Membrane Biology Institute of ZoologyChinese Academy of SciencesBeijingChina University of Chinese Academy of Sciences BeijingChina Institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijingChina

Spaceflight-associated immune system weakening ultimately limits the ability of humans to expand their presence beyond the earth's orbit. A mechanistic study of microgravity-regulated immune cell function is necessary to overcome this challenge. Here, we demonstrate that both spaceflight (real) and simulated microgravity significantly reduce macrophage differentiation, decrease macrophage quantity and functional polarization, and lead to metabolic reprogramming, as demonstrated by changes in gene expression profiles. Moreover, we identified RAS/ERK/NFκB as a major microgravity-regulated pathway. Exogenous ERK and NFκB activators significantly counteracted the effect of microgravity on macrophage differentiation. In addition, microgravity also affects the p53 pathway, which we verified by RT-qPCR and Western blot. Collectively, our data reveal a new mechanism for the effects of microgravity on macrophage development and provide potential molecular targets for the prevention or treatment of macrophage differentiation deficiency in spaceflight.

关键词： Microgravity Hematopoietic progenitor cells Macrophage differentiation Macrophage polarization RAS/ERK/NFκB pathway

Key Frame Extraction of Surveillance Video Based on Fractional Fourier Transform

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Journal of Beijing Institute of Technology 2021年第3期30卷 311-321页

作者： Yunzuo zhang jiayu zhang Ran Tao the School of Information Science and Technology Shijiazhuang Tiedao University the School of Information and Electronics Beijing Institute of Technology

With the vigorous development of national infrastructure construction and public information construction, video surveillance systems have gradually penetrated various fields. The current key frame extraction technology has inadequate target details and inaccurate judgment of local actions. Addressing this problem, a key frame extraction method based on fractional Fourier transform is proposed. This method obtained the phase spectra information of different orders by performing fractional Fourier transform on the surveillance video frames. Next, the method designed an adaptive algorithm based on the golden section point to select the transformation ***, the phase spectrum information of two adjacent frames was used to characterize the changes in the global and local motion states of the target. The final step was to extract key frames based on this. Experimental results show that, compared with the previous methods, the key frames extracted by the method proposed in this paper can correctly capture the changes in the global and local motion states of the target.

关键词： fractional Fourier transform (FRFT) phase spectrum key frame extraction adaptation local motion status

Cu-doped Bi/Bi_(2)WO_(6) catalysts for efficient N_(2) fixation by photocatalysis

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Frontiers of Chemical Science and Engineering 2023年第10期17卷 1412-1422页

作者： Xiaojing Li Chunran Zhao Junfeng Wang jiayu zhang Ying Wu Yiming He Department of Materials Science and Engineering Zhejiang Normal UniversityJinhua 321004China Key Laboratory of Solid State Optoelectronic Devices of Zhejiang province Zhejiang Normal UniversityJinhua 321004China Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Institute of Physical ChemistryZhejiang Normal UniversityJinhua 321004China

In this paper,Cu-doped Bi_(2)WO_(6)was synthesized via a solvothermal method and applied it in photocatalytic N_(2)*** results showed the presence of a small amount of metallic Bi in the photocatalyst,indicating that the synthesized photocatalyst is actually Bi/Cu-Bi_(2)WO_(6)*** doped Cu had a valence state of+2 and most likely substituted the position of Bi^(3+).The introduced Cu did not affect the metallic Bi content,but mainly influenced the energy band structure of Bi_(2)WO_(6).The band gap was slightly narrowed,the conduction band was elevated,and the work function was *** reduced work function improved the transfer and separation of charge carriers,which mainly caused the increased *** optimized NH_(3)generation rates of Bi/Cu-Bi_(2)WO_(6)reached 624 and 243μmol·L^(-1)·g^(-1)·h^(-1)under simulated solar and visible light,and these values were approximately 2.8 and 5.9 times higher those of Bi/Bi_(2)WO_(6),*** research provides a method for improving the photocatalytic N_(2)fixation and may provide more information on the design and preparation of heteroatom-doped semiconductor photocatalysts for N_(2)-to-NH_(3)conversion.

关键词： Bi_(2)WO_(6) Cu doping work function photocatalytic N_(2)fixation charge separation

Chemical cleaning of fouled PVC membrane during ultrafiltration of algal-rich water

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Journal of Environmental Sciences 2011年第4期23卷 529-536页

作者： Yan zhang jiayu Tian Heng Liang Jun Nan Zhonglin Chen Guibai Li State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology Harbin 150090 China.

Cleaning of hollow-fibre polyvinyl chloride （PVC） membrane with different chemical reagents after ultrafiltration of algal-rich water was investigated. Among the tested cleaning reagents （NaOH, HCl, EDTA, and NaClO）, 100 mg/L NaClO exhibited the best performance （88.4% ± 1.1%） in removing the irreversible fouling resistance. This might be attributed to the fact that NaClO could eliminate almost all the major foulants such as carbohydrate-like and protein-like materials on the membrane surface, as confirmed by Fourier transform infrared spectroscopy analysis. However, negligible irreversible resistance （1.5% ± 1.0%） was obtained when the membrane was cleaning by 500 mg/L NaOH for 1.0 hr, although the NaOH solution could also desorb a portion of the major foulants from the fouled PVC membrane. Scanning electronic microscopy and atomic force microscopy analyses demonstrated that 500 mg/L NaOH could change the structure of the residual foulants on the membrane, making them more tightly attached to the membrane surface. This phenomenon might be responsible for the negligible membrane permeability restoration after NaOH cleaning. On the other hand, the microscopic analyses reflected that NaClO could effectively remove the foulants accumulated on the membrane surface.

关键词： membrane fouling chemical cleaning algal-rich water NaOH NaClO

Use of evergreen and deciduous plants by nocturnal-roosting birds:A case study in Beijing

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Avian Research 2024年第2期15卷 211-218页

作者： Yexi Zhao jiayu zhang Zihan Li Qinmijia Xie Xin Deng Chenxi zhang Nan Wang School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083China

With continually increasing urbanization,the land cover in urban areas continues to change,resulting in the loss of *** are highly sensitive to changes in *** forest birds perch on plants that provide increased safety to reduce the risk of predation,and small birds may also consider insulation when using roosting plants in winter because of cold *** plants thus shape the nocturnal roosting environment of urban birds,and proper planting is essential for the survival of birds at *** use of roosting plants by urban birds should therefore be studied to provide a reference for *** the current study,we observed 1865 nocturnal roosting birds in Beijing from 2021 to 2022,with 23 species of birds from 12 families and 45 species of plants from 22 families *** chinensis exhibited the highest bird rarity-weighted richness,followed by Fraxinus pennsylvanica,Phyllostachys propinqua,Pinus tabuliformis,and Ulmus *** diameter at breast height,tree height,and crown width of plants used by birds was largest in summer and smallest in winter,and the perch height of birds was the highest in spring and summer and the lowest in *** used the highest proportion of deciduous plants in summer and the highest proportion of evergreen plants in winter.A significant seasonal difference in the use of evergreen and deciduous plants by small birds was noted,with a preference for deciduous plants in summer and evergreen plants in winter,while this preference was not found in large *** findings indicate that evergreen plants provide a vital nocturnal roosting environment for small birds in *** provide a better nocturnal roosting habitat for urban birds,we recommend paying attention to the combination of evergreen and deciduous plants when carrying out landscape construction.

关键词： Nocturnal roosting Roosting plant Seasonal variation Urban bird

Leaky Cable Fixture Detection in Railway Tunnel Based on RW DCGAN and Compressed GS-YOLOv5

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Intelligent Automation & Soft Computing 2023年第7期37卷 1163-1180页

作者： Suhang Li Yunzuo zhang Ruixue Liu jiayu zhang Zhouchen Song Yutai Wang School of Information Science and Technology Shijiazhuang Tiedao UniversityShijiazhuang050043China Australian National University Canberra2600ACTAustralia

The communication system of high-speed trains in railway tunnels needs to be built with leaky cables fixed on the tunnel wall with special *** ensure safety,checking the regular leaky cable fixture is necessary to elimi-nate the potential *** present,the existing fixture detection algorithms are difficult to take into account detection accuracy and speed at the same *** faulty fixture is also insufficient and difficult to obtain,seriously affecting the model detection *** solve these problems,an innovative detection method is proposed in this ***,we presented the Res-Net and Wasserstein-Deep Convolution GAN(RW-DCGAN)to implement data augmentation,which can enable the faulty fixture to export more high-quality and irregular ***,we proposed the Ghost SENet-YOLOv5(GS-YOLOv5)to enhance the expression of fixture feature,and further improve the detection accuracy and ***,we adopted the model compression strategy to prune redundant channels,and visualized training details with Grad-CAM to verify the reliability of our *** results show that the algorithm model is 69.06%smaller than the original YOLOv5 model,with 70.07%fewer parameters,2.1%higher accuracy and 14.82 fps faster speed,meeting the needs of tunnel fixture detection.

关键词： Leaky cable fixture detection RW-DCGAN compressed strategy GS-YOLOv5