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Modeling limit force capacities of high force to volume lead extrusion dampers

Frontiers of Structural and Civil Engineering 2021年第3期15卷 609-622页

作者： V.VISHNUPRIYA geoffrey.w.rodgers J.geoffrey CHASE Department of Mechanical Engineering University of CanterburyChristchurch8140New Zealand QuakeCoRE NZ Centre for Earthquake Resilience Christchurch8041New Zealand

Lead extrusion dampers are supplemental energy-dissipation devices that are used to mitigate seismic structural *** volumetric sizes and high force capacities define high-force-to-volume(HF2V)devices,which can absorb significant response energy without sacrificial ***,the design of such devices for specific force capacities has proven difficult based on the complexities of their internal reaction mechanisms,leading to the adoption of empirical *** study developed upper-and lower-bound force capacity estimates from analytical mechanics based on direct and indirect metal extrusion for guiding *** derived equations are strictly functions of HF2V device geometric parameters,lead material properties,and extrusion *** upper-bound estimates from direct and indirect extrusion are denoted as(F_(UB,1),F_(UB,2))and(F_(UB,3),F_(UB,4)),respectively,and the lower-bound estimates are denoted as(F_(LB),F_(LB,1))based on the combination of extrusion and friction *** proposed models were validated by comparing the predicted bounds to experimental force capacity data from 15 experimental HF2V device *** experimental device forces all lie above the lower-bound estimates(F_(LB),F_(LB,1))and below the upper-bound estimates(F_(UB,1),F_(UB,2),F_(UB,4)).Overall,the(F_(LB),F_(UB,2))pair provides wider bounds and the(F_(LB,1),F_(UB,4)/F_(UB,1))pair provides narrower ***(F_(LB,1),F_(UB,1))pair has a mean lower-bound gap of 36%,meaning the lower bound was 74%of the actual device force on *** mean upper-bound gap was 33%.The bulge area and cylinder diameter of HF2V devices are key parameters affecting device *** relatively tight bounds provide useful mechanics-based predictive design guides for ensuring that device forces are within the targeted design range after manufacturing.

关键词： extrusion lead dampers upper and lower bound analytical modelling limit force

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混凝土自复位墙结构地震全过程损伤分析

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建筑结构学报 2024年第2期45卷 189-204页

作者：鲁懿虬 HENRY Richard S 周颖 rodgers geoffrey w 杨群顾安琪同济大学土木工程学院上海200092 奥克兰大学土木与环境系新西兰奥克兰1010 坎特伯雷大学土木与自然资源工程系新西兰基督城8140

后张法预应力混凝土自复位墙是一种有效的可恢复功能结构。虽然自复位墙自身在地震中损伤较小,但其与周边构件的变形不协调可使结构损伤严重。为控制结构层面的损伤,设计了1个框架-自复位墙结构,对自复位墙底、梁柱节点、墙梁节点、墙-... 详细信息

后张法预应力混凝土自复位墙是一种有效的可恢复功能结构。虽然自复位墙自身在地震中损伤较小,但其与周边构件的变形不协调可使结构损伤严重。为控制结构层面的损伤,设计了1个框架-自复位墙结构,对自复位墙底、梁柱节点、墙梁节点、墙-基础连接、柱-基础连接以及墙-板连接开展损伤控制设计,并对设计的结构进行足尺振动台试验。结构共经历了39次不同设计工况下不同烈度的地震激励,峰值加速度最大达1.0g,位移角最大达3.3%。对结构在历次地震作用下整体、局部构件和节点的损伤发展进行全过程定量分析,结果表明:自复位墙-开槽梁结构在地震作用下的损伤能够得到有效控制,其中多遇、设防地震作用下结构基本无损伤,罕遇地震作用下墙底损伤仅限角部剥落且面积仅为400 cm2,楼板有开裂且裂缝最大仅为1.2 mm,梁端剥落可忽略;自复位墙-开槽梁结构可使整个结构在不同设计位移角下实现多遇、设防地震不坏,罕遇地震小修甚至不修的抗震性能目标;设计的连接方式解决了结构中构件之间的变形不协调问题,提高了自复位墙结构层面的可修复性。

关键词：自复位墙开槽梁墙板连接振动台试验结构损伤

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Deep learning for joint channel estimation and feedback in massive MIMO systems

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Digital Communications and Networks 2024年第1期10卷 83-93页

作者： Jiajia Guo Tong Chen Shi Jin geoffrey Ye Li Xin wang Xiaolin Hou National Mobile Communications Research Laboratory Southeast UniversityNanjing210096China Department of Electrical and Electronic Engineering Imperial College LondonLondonSW72AZUK DOCOMO Beijing Communications Laboratories Co. LtdBeijingChina

The great potentials of massive Multiple-Input Multiple-Output(MIMO)in Frequency Division Duplex(FDD)mode can be fully exploited when the downlink Channel State Information(CSI)is available at base ***,the accurate CsI is difficult to obtain due to the large amount of feedback overhead caused by massive *** this paper,we propose a deep learning based joint channel estimation and feedback framework,which comprehensively realizes the estimation,compression,and reconstruction of downlink channels in FDD massive MIMO *** networks are constructed to perform estimation and feedback explicitly and *** explicit network adopts a multi-Signal-to-Noise-Ratios(SNRs)technique to obtain a single trained channel estimation subnet that works well with different SNRs and employs a deep residual network to reconstruct the channels,while the implicit network directly compresses pilots and sends them back to reduce network *** module is also designed to generate data-bearing *** results show that the two proposed networks exhibit excellent performance of reconstruction and are robust to different environments and quantization errors.

关键词： Channel estimation CSI feedback Deep learning Massive MIMO FDD

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Chalcogenide Ovonic Threshold Switching Selector

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Nano-Micro Letters 2024年第5期16卷 1-40页

作者： Zihao Zhao Sergiu Clima Daniele Garbin Robin Degraeve geoffrey Pourtois Zhitang Song Min Zhu National Key Laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050People’s Republic of China University of Chinese Academy of Sciences Beijing 100029People’s Republic of China IMEC Kapedreef 75LeuvenBelgium

Today’s explosion of data urgently requires memory technologies capable of storing large volumes of data in shorter time frames,a feat unattain-able with Flash or *** Optane,commonly referred to as three-dimensional phase change memory,stands out as one of the most promising *** Optane with cross-point architecture is constructed through layering a storage element and a selector known as the ovonic threshold switch(OTS).The OTS device,which employs chalcogenide film,has thereby gathered increased attention in recent *** this paper,we begin by providing a brief introduction to the discovery process of the OTS ***,we summarize the key elec-trical parameters of OTS devices and delve into recent explorations of OTS materials,which are categorized as Se-based,Te-based,and S-based material ***,we discuss various models for the OTS switching mechanism,including field-induced nucleation model,as well as several carrier injection ***,we review the progress and innovations in OTS mechanism ***,we highlight the successful application of OTS devices in three-dimensional high-density memory and offer insights into their promising performance and extensive prospects in emerging applications,such as self-selecting memory and neuromorphic computing.

关键词： Non-volatile memory Ovonic threshold switch(OTS) Chalcogenide Selector

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Effects of soil metal(loid)s pollution on microbial activities and environmental risks in an abandoned chemical smelting site

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Journal of Environmental Sciences 2024年第9期143卷 60-70页

作者： Hao Li Jun Yao Jianli Liu Ning Min geoffrey Sunahara Dongyang Men Robert Duran School of water Resources and Environment Research Center of Environmental Science and EngineeringChina University of Geosciences(Beijing)Beijing 100083China Department of Natural Resource Sciences McGill University21111Lakeshore DriveSte-Anne-de-BellevueQuebecH9X 3V9Canada Equipe Environnement et Microbiologie MELODY groupUniversitéde Pau et des Pays de l’AdourE2S-UPPAIPREM UMR CNRS 5254BP 115564013 Pau CedexFrance

Abandoned chemical smelting sites containing toxic substances can seriously threaten and pose a risk to the surrounding ecological *** samples were collected from different depths(0 to 13 m)and analyzed for metal(loid)s content and fractionation,as well as microbial *** potential ecological risk indices for the different soil depths(ordered from high to low)were:1 m(D-1)>surface(S-0)>5 m(D-5)>13 m(D-13)>9 m(D-9),ranging between 1840.65-13,089.62,and representing extremely high environmental risks,of which Cd(and probably not arsenic)contributed to the highest environmental risk.A modified combined pollution risk index(MCR)combining total content and mobile proportion of metal(loid)s,and relative toxicities,was used to evaluate the degree of contamination and potential environmental *** the near-surface samples(S-0 and D-1 layers),the MCR considered that As,Cd,Pb,Sb,and Zn achieved high and alarming degrees of contamination,whereas Fe,Mn,and Ti were negligible or low to moderate pollution *** microcalorimetry and enzymatic activity measurements of contaminated soil samples were used to assess the microbial metabolic activity *** analysis elucidated the relationship between metal(loid)s exchangeable fraction or content and microbial activity characteristics(pwas low presumably due to heavy metal *** activity indicators and microcalorimetric growth rate(k)measurements were considered sensitive indicators to reflect the soil microbial activities in abandoned chemical smelting sites.

关键词： Abandoned chemical smelting sites Microbial activities Modified combined pollution risk Microcalorimetry Enzymatic activities

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A core-satellite self-assembled SERS aptasensor containing a“biological-silent region”Raman tag for the accurate and ultrasensitive detection of histamine

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Food Science and Human wellness 2024年第2期13卷 1029-1039页

作者： Chen Chen Yingfang Zhang Ximo wang Xuguang Qiao geoffrey I.N.waterhouse Zhixiang Xu Key Laboratory of Food Processing Technology and Quality Control in Shandong Province College of Food Science and EngineeringShandong Agricultural UniversityTai’an 271018China School of Chemical Sciences The University of AucklandAuckland 1142New Zealand

Herein,a novel interference-free surface-enhanced Raman spectroscopy(SERS)strategy based on magnetic nanoparticles(MNPs)and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine.A core-satellite SERS aptasensor was constructed by combining aptamer-decorated Fe_(3)O_(4)@Au MNPs(as the recognize probe for histamine)and complementary DNA-modified silver nanoparticles carrying 4-mercaptobenzonitrile(4-MBN)(Ag@4-MBN@Ag-c-DNA)as the SERS signal probe for the indirect detection of *** an applied magnetic field in the absence of histamine,the assembly gave an intense Raman signal at“Raman biological-silent”region due to *** the presence of histamine,the Ag@4-MBN@Ag-c-DNA SERS-tag was released from the Fe_(3)O_(4)@Au MNPs,thus decreasing the SERS *** optimal conditions,an ultra-low limit of detection of 0.65×10^(-3)ng/mL and a linear range 10^(-2)-10^5 ng/mL on the SERS aptasensor were *** histamine content in four food samples were analyzed using the SERS aptasensor,with the results consistent with those determined by high performance liquid *** present work highlights the merits of indirect strategies for the ultrasensitive and highly selective SERS detection of small biological molecules in complex matrices.

关键词： Surface-enhanced Raman spectroscopy Raman biological-silent region Aptamer Histamine detection Universal SERS-tag

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Evaluation of formation susceptibility and sand production potential in an offshore field,Niger Delta Basin,Nigeria

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Energy Geoscience 2024年第1期5卷 1-11页

作者： David O.Ubuara Yinka A.Olayinka Godwin O.Emujakporue geoffrey C.Soronnadi-Ononiwu Department of Geology University of Port HarcourtNigeria Mease Energy Nigeria Limited Port HarcourtNigeria Department of Geology University of IbadanNigeria Department of Physics University of Port HarcourtNigeria

wellbore instability and sand production are all common challenges in the Niger Delta oil province,resulting in high drilling and production cost as well as damage to oil *** vulnerability of lithologic formations to wellbore instability and resultant sand production is investigated in the four delineated reservoirs of the“Areo”field,western part of Niger Delta *** foundation for establishing the geomechanical properties in this study was a 1-dimensional mechanical earth model,using gamma ray(GR),density(RHOB),compressional slowness(DTC),and shear slowness(DTS)*** the Areo oil field,two wells(well 001 and well 002)were *** evaluated formations are still primarily composed of compacted shale and unconsolidated sandstone,with reservoir sand units exhibiting lower elastic and rock strength properties than shale *** compressibility and porosity make sand more brittle,while low compressibility and porosity make shale stiffer due to high *** maximum force that can be applied to a shale unit without causing it to fail is 17.23 MPa,which is the maximum average rock strength of the *** means that shale requires more vertical stress or pressure than sand does in order to deform it(15.06 MPa).The three sand prediction approaches used in the analysis of sand production predictions have cut-off values that are higher than the average values of the *** Schlumberger sand production index method(S/I)indicates that the reservoir has potential for sand influx in the two wells,with the average of the four reservoirs studied in wells 001 and 002 being 1.551012 psi and 1.141012 psi ***,when a formation's sand production index is less than 1.241012 psi,as it is in this study,the formation is likely to produce *** findings support the notion that the defined sandstone units are highly unconsolidated and have a high potential for producing sands;therefore,sand control techniques must be factored in

关键词： wireline log Stress Geo-mechanicanical characterization Sand prediction Niger delta

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SERS-tag techology in food safety and detection:sensing from the"fingerprint"region to the"biological-silent"region

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Journal of Future Foods 2024年第4期4卷 309-323页

作者： Chen Chen Ximo wang Ruiqiang wang geoffrey LN.waterhouse Zhixiang Xu College of Food Science and Engineering Shandong Agricutural UniversiyTai'an 271018China Shandong Cayon Testing Co. LtdJining 272000China School of Chemical Sciences The University of AucklandAnckland 1142New Zealand

Surface enhanced Raman spectroscopy(SERS)offers many advantages for the fast and sensitive detection of specific compounds,metal ions or pathogens in foods,motivating to its increasing utilization in food ***-tags,typically constructed using signal enhanced substrate,Raman reporter molecules,a biocompatible protective layer and a specific recognition element,provide a powerful tool for the analysis of food *** article reviews recent progress in the development of SERS-tags for food safety assessment covering SERS-tags with characteristic peaks in the“fingerprint”region(800-1800 cm-1)and the“biological-silent”region(1800-2800 cm-1).Following a brief description of SERS substrates,the design,synthesis and applications of SERS-tag are explored in *** application of SERS-tags technology for the detection of microorganisms,pesticides and antibiotics are then ***,the prospects of using SERS-tag in real-world food safety analysis are critically discussed.

关键词： Surface enhanced Raman spectroscopy SERS-tags Raman reporter molecule Fingerprint region Biological-silent region Food Safety

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Catatonia:A deep dive into its unfathomable depths

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world Journal of Psychiatry 2024年第2期14卷 210-214页

作者： Peter Phiri Gayathri Delanerolle Oliver Hope Tharangini Murugaiyan geoffrey Dimba Shanaya Rathod Zukiswa Zingela Research&Innovation Department Southern Health NHS Foundation TrustSouthampton SO303JBUnited Kingdom School of Psychology Faculty of Environmental and Life SciencesUniversity of SouthamptonSouthampton SO171BJHampshireUnited Kingdom Acute Inpatients Services Southern Health NHS Foundation TrustBasingstoke RG249RHUnited Kingdom Home Treatment Team South WestSurrey and Borders Partnerships NHS Foundation TrustGuildford GU27XLSurreyUnited Kingdom Faculty of Health Sciences Nelson Mandela UniversitySummerstrand 6001GqeberhaSouth Africa

This editorial addresses catatonia,a complex neuropsychiatric syndrome characterised by a spectrum of psychomotor *** editorial seeks to clarify the ambiguous aspects of catatonia,integrating recent research findings,including global studies and diagnostic *** discusses catatonia’s clinical manifestations,prevalence,and associated psychiatric and medical conditions,with particular emphasis on its frequent co-occurrence with schizophrenia and mood *** prevalence of catatonia,which varies across psychiatric populations,is illustrated by a significant study conducted in Nelson Mandela Bay,South *** study provides valuable insights into the effectiveness of the Bush-Francis Screening Instrument compared to the Diagnostic and Statistical Manual 5 criteria in diagnosing *** editorial evaluates treatment approaches,primarily focusing on benzodiazepines and electroconvulsive therapy,and discusses emerging therapeutic *** underscores the importance of robust diagnostic frameworks and early intervention in managing catatonia,as recommended by the latest evidence-based consensus ***,it suggests future research directions,particularly in exploring the neurobiological and genetic factors of catatonia,to enhance our understanding and improve treatment *** editorial succinctly aims to demystify catatonia and provide valuable insights for clinicians and researchers in mental health care.

关键词： Catatonia Schizophrenia Neuropsychiatry Benzodiazepines Electroconvulsive therapy Bush-Francis screening instrument Diagnosis

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Optimization of Methylene Blue Dye Adsorption onto Coconut Husk Cellulose Using Response Surface Methodology: Adsorption Kinetics, Isotherms and Reusability Studies

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Journal of Materials Science and Chemical Engineering 2024年第2期12卷 1-18页

作者： Frank Ouru Omwoyo geoffrey Otieno School of Chemistry and Material Science Technical University of Kenya Nairobi Kenya

In this study, coconut husk cellulose was employed as a cost-effective and environmentally friendly adsorbent to eliminate methylene blue (MB) dye from aqueous solutions. The successful development of response surface methodology paired with a central composite design (RSM-CCD) enabled the optimization and modelling of the adsorption process. The study investigated the individual and combined effects of three variables (pH, contact time, and initial MB dye concentration) on the adsorption of MB dye onto coconut husk cellulose. The developed RSM-CCD model exhibited a remarkable degree of precision in predicting the removal efficiency of MB dye within the specified experimental parameters. This was demonstrated by the strong regression parameters, with an R2 value of 99.79% and an adjusted R2 value of 99.6%. The study depicted that the optimal parameters for attaining a 98.8827% removal of MB dye using coconut husk cellulose were as follows: an initial MB dye concentration of 30 mg∙L−1, contact time of 120 minutes, and pH 7 at a fixed adsorbent dose of 0.5 g. The Freundlich isotherm model provided the most satisfactory description of the equilibrium adsorption isotherms, suggesting that MB dye adsorption onto coconut husk cellulose occurs on a heterogeneous surface. The experimental results demonstrated a strong agreement with the pseudo-second-order kinetics model, indicating that the number of active sites present on the cellulose adsorbent predominantly influences the adsorption process of MB dye. Additionally, the adsorbent made from coconut husk cellulose exhibited the potential to be reused, as it retained its efficiency for a maximum of three cycles of adsorption of MB dye. The results of this study show that coconut husk cellulose has the potential to be an effective and sustainable adsorbent for removing MB dye from aqueous solutions.

关键词： Adsorption Kinetics Isotherms Optimization Response Surface Methodology Cellulose

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