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Occurrence of viable but non-culturable(VBNC)pathogenic bacteria in tap water of public places

Frontiers of Environmental Science & Engineering 2024年第3期18卷 115-129页

作者： Lizheng Guo Xinyan Xiao Kassim Chabi Yiting zhang Jingjing Li su Yao Xin Yu China National Research Institute of Food and Fermentation Industries Co. Ltd.China Center of Industrial Culture CollectionBeijing 100015China Key Laboratory of Urban Environment and Health Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China College of Environment&Ecology Xiamen UniversityXiamen 361102China

Viable but non-culturable(VBNC)bacteria have been detected in source water and effluent of drinking water treatment processes,leading to significant underestimation of viable cell *** information exists on VBNC bacteria in tap water,particularly in public *** address this gap,a comprehensive nine-month study was conducted in a major city in south-eastern China,using culture-based and quantitative PCR with propidium monoazide(PMA)dye ***-five samples were collected from five representative public places(railway station,campus,hospital,shopping mall,and institution).The findings revealed that culturable bacteria represented only 0–17.51%of the viable 16S rRNA genes,suggesting that the majority of viable bacteria existed in an uncultured or VBNC ***,opportunistic pathogens such as Escherichia coli,Enterococcus faecalis,Pseudomonas aeruginosa,Salmonella sp.,and Shigella *** primarily detected as VBNC cells,with concentrations ranging from 1.03×10^(0)to 3.01×10^(3),1.20×10^(0)to 1.42×10^(2),1.32×10^(0)to 8.82×10^(0),1.00×10^(0)to 6.71×10^(1),and 2.07×10^(0)to 1.93×10^(2)cell equivalent/100 mL,*** *** was observed in tap water after prolonged stagnation,indicating potential risks associated with bacterial *** and temporal factors accounted for 17.1%and 26.0%,respectively,of the variation in tap water community structure during the sampling period,as revealed by 16S rRNA amplicon *** study provides quantitative insights into the occurrence of VBNC bacteria in tap water and highlights the need for more sensitive monitoring methods and microbial control techniques to enhance tap water safety in public locations.

关键词： VBNC Pathogenic bacteria PMA treatment Public tap water Community structure

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Hydrodynamic resistance of pore–throat structures and its effect on shale oil apparent permeability

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International Journal of Coal Science & Technology 2024年第2期11卷 101-110页

作者： Wendong Wang Qian zhang Jilong Xu Da Zheng Lifeng Liu Yuliang su Key Laboratory of Unconventional Oil and Gas Development Ministry of EducationQingdao 266580China School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580ShandongChina PetroChina Oil Gas and New Energies CompanyBeijing 100083China Research Institute of Petroleum Exploration and Development PetroChinaBeijing 100083China

Oil transport is greatly affected by heterogeneous pore–throat structures present in *** is therefore very important to accurately characterize pore–throat ***,it remains unclear how pore–throat structures affect oil transport *** this paper,using finite element(FE)simulation and mathematical modeling,we calculated the hydrodynamic resistance for four pore–throat *** addition,the influence of pore throat structure on shale oil permeability is *** to the results,the hydrodynamic resistance of different pore throat structures can vary by 300%.The contribution of additional resistance caused by streamline bending is also in excess of 40%,even without slip ***-thermore,Pore–throat structures can affect apparent permeability by more than 60%on the REV scale,and this influence increases with heterogeneity of pore size distribution,organic matter content,and organic matter ***,modeling shale oil flow requires consideration of porous–throat structure and additional resistance,otherwise oil recovery and flow capacity may be overestimated.

关键词： Pore–throat structure Hydrodynamic resistance Apparent permeability REV-scale Shale oil

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Improved remote sensing image target detection based on YOLOv7

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Optoelectronics Letters 2024年第4期20卷 234-242页

作者： XU Shuanglong CHEN Zhihong zhang Haiwei XUE Lifang su Huijun School of Integrated Circuit Science and EngineeringTianjin University of Technology Tianjin 300384China

Remote sensing images are taken at high altitude from above,with complex spatial scenes of images and a large number of target *** detection of image targets on large scale remote sensing images suffers from the problem of small target size and target *** paper proposes an improved model for remote sensing image detection based on you only look once version 7(YOLOv7).First,the small-scale detection layer is added to reacquire tracking frames to improve the network’s recognition ability of small-scale targets,and then Bottleneck Transformers are fused in the backbone to make full use of the convolutional neural network(CNN)+Transformer architecture to enhance the feature extraction ability of the *** that,the convolutional block attention module(CBAM)mechanism is added in the head to improve the model’s ability of small-scale ***,the non-maximum suppressed(NMS)of YOLOv7 algorithm is changed to distance intersection over union-non maximum suppression(DIOU-NMS)to improve the detection ability of overlapping targets in the *** results show that the method in this paper can improve the detection rate of small-scale targets in remote sensing images and effectively solve the problem of high overlap and is tested on the NWPU-VHR10 and DOTA1.0 datasets,and the accuracy of the improved model is improved by 6.3%and 4.2%,respectively,compared with the standard YOLOv7 algorithm.

关键词： image network union

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Stability analysis of loose accumulation slopes under rainfall:case study of a high‑speed railway in Southwest China

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Railway Engineering Science 2024年第1期32卷 95-106页

作者： Xin Wang Qian su Zongyu zhang Feihu Huang Chenfang He School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China Key Laboratory of High‑Speed Railway Engineering Ministry of Education School of Civil EngineeringSouthwest Jiaotong UniversityChengdu 610031China CCCC Second Highway Consultants Co. Ltd.Wuhan 430056China

The high and steep slopes along a high-speed railway in the mountainous area of Southwest China are mostly composed of loose accumulations of debris with large internal pores and poor stability,which can easily induce adverse geological disasters under rainfall *** ensure the smooth construction of the high-speed railway and the subsequent safe operation,it is necessary to master the stability evolution process of the loose accumulation slope under *** article simulates rainfall using the finite element analysis software’s hydromechanical coupling *** slope stability under various rainfall situations is calculated and analysed based on the strength reduction *** validate the simulation results,a field monitoring system is established to study the deformation characteristics of the slope under *** results show that rainfall duration is the key factor affecting slope *** a constant amount of rainfall,the stability of the slope decreases with increasing duration of ***,when the amount and duration of rainfall are constant,continuous rainfall has a greater impact on slope stability than intermittent *** setting of the field retaining structures has a significant role in improving slope *** field monitoring data show that the slope is in the initial deformation stage and has good stability,which verifies the rationality of the numerical simulation *** research results can provide some references for understanding the influence of rainfall on the stability of loose accumulation slopes along high-speed railways and establishing a monitoring system.

关键词： High-speed railway Loose accumulation slope Slope stability analysis Rainfall effect Strength reduction

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A Novel Approach of Electromagnetic Compatibility Conducted susceptibility Analysis Based on Gaussian Even Pulse Signal

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Chinese Journal of Electronics 2024年第2期33卷 472-478页

作者： Youwei MENG Yanhua PENG Haoyang zhang Lilin LI Donglin su The School of Electronic and Information Engineering Beihang University The Institute of Electromagnetic Compatibility Technology Beihang University The Research Institute for Frontier Science Beihang University

The purpose of the electromagnetic compatibility conducted susceptibility test for interconnected cables in the system is to evaluate its ability to operate acceptably when subjected to interference. We propose a novel conducted susceptibility analysis approach: by injecting the Gaussian even pulse signal, we find that the susceptibility threshold of the system shows two different patterns with the change of signal parameters; then we locate the cause of the susceptibility of the device by analyzing the threshold level curves. The effectiveness of the proposed approach is verified by testing with devices containing digital modules such as navigation receivers. The proposed approach facilitates a deeper understanding of the susceptibility mechanism of systems and their appropriate electromagnetic compatibility design.

关键词： Analytical models Navigation Interference Receivers Electromagnetic compatibility Physical layer Time-domain analysis

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Enhanced wear prediction of tunnel boring machine disc cutters for accurate remaining useful life estimation using a hybrid model

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 642-662页

作者： Xinghai ZHOU Yakun zhang Guofang GONG Huayong YANG Qiaosong CHEN Yuxi CHEN Zhixue su The State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou 310027China Guangzhou Rail Transit Construction Engineering Consulting Co. Ltd.Guangzhou 510000China China Railway Engineering Equipment Group Co. Ltd.Zhengzhou 450016China

In tunnel construction with tunnel boring machines(TBMs),accurate prediction of the remaining useful life(RUL)of disc cutters is critical for timely maintenance and replacement to avoid delays and cost *** paper introduces a novel hybrid model,integrating fundamental and data-driven approaches,to enhance wear prediction of TBM disc cutters and enable accurate RUL *** fundamental model is improved by incorporating composite wear mechanisms and load estimation techniques,showcasing superior prediction accuracy compared to single-mechanism ***,the hybrid model innovatively incorporates a data-driven supplementary residual term into the improved fundamental model,leading to a high-performance wear prediction *** actual field data from a highway tunnel project in Shenzhen,the performance of the hybrid model is rigorously tested and compared with pure fundamental and data-driven *** hybrid model outperforms the other models,achieving the highest accuracy in predicting TBM disc cutter wear(mean absolute error(MAE)=0.53,root mean square error(RMSE)=0.64).Furthermore,this study thoroughly analyzes the hybrid model’s generalization capability,revealing significant impacts of geological conditions on prediction *** model’s generalization capability is also improved by expanding and updating the data *** RUL estimation results provided by the hybrid model are straightforward and effective,making it a valuable tool by which construction staff can monitor TBM disc cutters.

关键词： tunnel boring machine disc cutter wear prediction remaining useful life field data hybrid model

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Fabricating functionally graded Fe-Cr-Co permanent magnetic alloys via laser powder bed fusion

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Journal of Iron and Steel Research International 2024年第3期31卷 729-737页

作者： Ya-zhou He Ya-qing Hou Peng Shen Hao zhang Dong Zhou Hang su Central Iron and Steel Research Institute Co. Ltd.Beijing 100081China Material Digital R&D Center China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China

Laser powder bed fusion(LPBF)in-situ alloying technology offers the possibility to construct gradient materials with varied structures and *** graded Fe-Cr-Co permanent magnetic alloys were fabricated by LPBF and in-situ alloying mixed powders of Fe,Cr,and Co *** effects of different Fe,Cr and Co contents on the microstructure,magnetic properties and hardness of Fe-Cr-Co alloys prepared by LPBF were *** as-built Fe-Cr-Co alloys present a single body-centered-cubic phase and have a homogeneous distribution of *** mechanical properties and magnetic properties of the compositionally graded sample show a gradient *** the increase in Cr content,the Vickers hardness of the sample increases,and the saturation magnetization of the sample *** optimal magnetic properties in an isotropic state are given as coercivity HcB=21.65 kA/m,remanence Br=0.70 T and energy product(BH)_(max)=5.35 kJ/m^(3),which are comparable to or higher than the reported magnetic properties in an isotropic state prepared by traditional powder *** in-situ alloying technology has the potential to further explore Fe-Cr-Co magnetic materials,such as those consisting of multiple or more constituent elements,and to maximize the compositional flexibility of magnetic materials.

关键词： Fe-Cr-Co alloy Laser powder bed fusion In-situ alloying Functional material Magnetic property

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Critical Role of Ethylene-Propylene Block Copolymer in Impact Polypropylene Copolymer

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Chinese Journal of Polymer Science 2024年第3期42卷 344-351,I0007页

作者： Yu-Hui Tang Na zhang Wei Bao Wei Jiang Yuan Lin Zhao-Hui su State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Ethylene-propylene block copolymer(EbP) is a vital component in impact polypropylene copolymer(IPC), yet its distribution in the multiphase composite material and how it influences the phase structure and the mechanical properties are not well understood. In this work,four IPCs were investigated by atomic force microscopy-infrared(AFM-IR) to assess the phase compositions in situ, based on which in conjunction with the chain microstructure information obtained ex situ the distributions of the copolymer components were derived for each alloy. For the IPCs whose EbP comprises long P and long E segments, the EbP fraction was found to phase separate from the rubber and the PP matrix to form the cores of the disperse particles with the E-P segmented copolymer(EsP). In contrast, in the IPC with EbP composed of long P and short E segments, the EbP fraction formed an outer shell for the rubber particles with the cores comprising the EsP alone, and this IPC, containing a lower E comonomer content than its counterpart, exhibited both better impact resistance and higher flexural modulus. These results clarify how the chain structure of EbP governs the phase morphology in IPC, which in turn impacts the properties of the composite material.

关键词： Impact polypropylene copolymers AFM-IR Ethylene-propylene block copolymers Core-shell rubber particles

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Solid superacid catalysts promote high-performance carbon dots with narrow-band fluorescence emission for luminescence solar concentrators

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Chinese Chemical Letters 2024年第8期35卷 437-442页

作者： Rui Cheng Xin Huang Tingting zhang Jiazhuang Guo Jian Yu su Chen State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 210009China Jiangsu Key Laboratory of Fine Chemicals and Functional Polymer Materials Nanjing 210009China

Facile and efficient method for constructing carbon dots(CDs)with narrow full width at half maximum(FWHM)is a major challenge in the field,and researches on regulating the FWHM of CDs are also rare and *** this work,we delved into the synthesis of CDs with narrow fluorescence emission FWHM(NFEF-CDs)in the m-phenylenediamine(m-PD)/ethanol system,utilizing solid superacid resin as cata-lyst with solvothermal *** resulting NFEF-CDs exhibit a photoluminescent(PL)emission peak at 521 nm with a narrow FWHM of 41 nm,an absolute PL quantum yield(QY)of 80%,and display excitation-independent PL *** comprehensive characterization,we identified the protonation of edge amino on NFEF-CDs as the key factor in achieving the narrow ***,we validated the broad applicability of solid superacid resins as catalysts for synthesizing CDs with narrow FWHM in the m-PD/ethanol ***,we utilized a self-leveling method to prepare NFEF-CDs film on the surface of poly(methyl methacrylate)(PMMA)substrate and investigated the solid-state fluorescence properties of NFEF-CDs as well as their performance as luminescence solar concentrator(LSC)for photovoltaic *** results revealed that the as-prepared LSC exhibit an internal quantum efficiency(η_(int))of 42.39%and an optical efficiency(η_(opt))of 0.68%.These findings demonstrate the promising prospects of NFEF-CDs in the field of LSCs and provide a theoretical basis for their application in photovoltaic conversion.

关键词： Carbon dots Narrow full width at half maximum Solid-state fluorescence Luminescence solar concentrators Photovoltaic conversion

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Ion Channel Dysregulation Following Intracerebral Hemorrhage

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Neuroscience Bulletin 2024年第3期40卷 401-414页

作者： Xiangyu zhang Yan zhang Qiuyang su Yang Liu Zhe Li V.Wee Yong Mengzhou Xue Department of Cerebrovascular Diseases The Second Afliated Hospital of Zhengzhou UniversityZhengzhou 450000China Academy of Medical Science Zhengzhou UniversityZhengzhou 450000China Hotchkiss Brain Institute and Department of Clinical Neurosciences University of CalgaryCalgaryAB T2N 1N4Canada

Injury to the brain after intracerebral hemorrhage(ICH)results from numerous complex cellular *** present,effective therapy for ICH is limited and a better understanding of the mechanisms of brain injury is necessary to improve *** is increasing evidence that ion channel dysregulation occurs at multiple stages in primary and secondary brain injury following *** channels such as TWIK-related K+channel 1,sulfonylurea 1 transient receptor potential melastatin 4 and glutamate-gated channels affect ion homeostasis in *** in turn participate in the formation of brain edema,disruption of the blood-brain barrier,and the generation of *** this review,we summarize the interaction between ions and ion channels,the effects of ion channel dysregulation,and we discuss some therapeutics based on ion-channel modulation following ICH.

关键词： Intracerebral hemorrhage Ion dyshomeostasis sulfonylurea 1 transient receptor potential melastatin 4 TWIK-related K+channel 1 N-methyl-Daspartate receptor Transient receptor potential vanilloid 4

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