检索结果-南通市图书馆

Review of the Configuration and Transient Stability of Large-scale Renewable Energy Generation through Hybrid DC Transmission

在线全文

学校读者我要写书评

暂无评论

CES Transactions on Electrical Machines and Systems 2024年第2期8卷 115-126页

作者： Xinshou Tian Yongning Chi Longxue Li Hongzhi Liu Institute of Energy Power Innovation North China Electric Power UniversityBeijing 102206China China Electric Power Research Institute No.15Xiaoying East RoadQingheHaidian DistrictBeijing 100192China.

Based on the complementary advantages of Line Commutated Converter(LCC)and Modular Multilevel Converter(MMC)in power grid applications,there are two types of hybrid DC system topologies:one is the parallel connection of LCC converter stations and MMC converter stations,and the other is the series connection of LCC and MMC converter stations within a single *** hybrid DC transmission system faces broad application prospects and development potential in large-scale clean energy integration across regions and the construction of a new power system dominated by new energy sources in *** paper first analyzes the system forms and topological characteristics of hybrid DC transmission,introducing the forms and topological characteristics of converter-level hybrid DC transmission systems and system-level hybrid DC transmission ***,it analyzes the operating characteristics of LCC and MMC inverter-level hybrid DC transmission systems,provides insights into the transient stability of hybrid DC transmission systems,and typical fault ride-through control ***,it summarizes the networking characteristics of the LCC-MMC series within the converter station hybrid DC transmission system,studies the transient characteristics and fault ridethrough control strategies under different fault types for the LCC-MMC series in the receiving-end converter station,and investigates the transient characteristics and fault ride-through control strategies under different fault types for the LCC-MMC series in the sending-end converter station.

关键词： Hybrid DC transmission Transient stability Configuration Control system

Unveiling the silent crisis:global burden of suicide‑related deaths among children aged 10–14 years

在线全文

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2024年第4期20卷 371-391页

作者： Irmina Maria Michalek Pawel Koczkodaj Marzena Michalek Florentino Luciano Caetano dos Santos Department of Cancer Epidemiology and Primary Prevention Maria Sklodowska-Curie National Research Institute of Oncologyul.Wawelska 15 BWarsawPoland Private Psychiatric Practice-Marzena Michalek MDSiedlcePoland Harvard Business School Harvard UniversityBostonMAUSA

Background The rise in suicides among children aged 10–14 years demands urgent attention *** study aims to assess the global burden of suicide-related deaths in this age group from 1990 to 2019,considering factors such as sex,geography,and sociodemographics,to inform prevention strategies and *** The data from Global Burden of Disease 2019,encompassing 204 countries and territories,were analyzed to investigate deaths and years of life lost(YLLs)due to suicide among children aged 10–14 *** analyses,including mortality rates,YLLs,and the sociodemographic index(SDI),were conducted using standardized *** In 2019,a total of 8327[95%uncertainty interval(UI)=7073–9685]children aged 10–14 years died globally due to suicide,with a mortality rate of 1.30(95%UI=1.10–1.51)per 100,*** rates varied across countries/territories ranging between 0.05(95%UI=0.02–0.10)in South Africa and 7.49(95%UI=5.13–10.57)in *** contribution of suicide-related deaths to all-cause mortality ranged from 0.07%(95%UI=0.04%–0.15%)in South Africa to 33.02%(95%UI=24.36%–41.53%)in ***,there were approximately 636,196(95%UI=540,383–740,009)YLLs due to suicide,with a rate of 99.07(95%UI=84.15–115.23)per 100,*** association between SDI and suicide-related deaths was evident,with higher contributions observed in countries with higher *** This study reveals a concerning global burden of suicide-related deaths among children aged 10–14 *** progress in reducing mortality rates,suicide remains a significant *** overall rates have declined,the percentage of deaths caused by suicide in this age group is increasing.

关键词： Early adolescent Global Burden of Disease Incidence Suicide Years of life lost

Breeding phase and outcome determine space use in European rollers Coracias garrulus prior to migration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2024年第2期70卷 137-149页

作者： Flavio Monti Sanja Barisic Sebastian Cannarella Davor Cikovic Vesna Tutis JelenaKralj Carlo Catoni aUniversity of Siena Department of Physical SciencesEarth and EnvironmentVia Mattioli 453100 SienaItaly Institute of Ornithology Croatian Academy of Sciences and ArtsGunduliceva 24HR-1000 ZagrebCroatia Ornis italica Piazza Crati 1500199 RomeItaly

The breeding period is a demanding and time-constrained phase for migratory bird *** outcome and duration can interact with the extent and duration of post-breeding movements,resulting in individual differences in space use ultimately influencing later stages of the annual *** present space-use and home range estimates during the breeding season for 21 European rollers Coracias garrulus tracked between 2018 and 2022,in Italy and *** high-resolution spatial GPS data coupled with regular nest-box monitoring,we analyzed dif-ferences in space use during the incubation/nestling period versus post-breeding period prior to migration,accounting for the breeding outcome(successful ***).We found that adult movements were strongly reduced during the first phase,whereas increased in the post-breeding phase,especially for failed *** breeders remained in the surroundings of the nest site,whereas unsuccessful ones tended to abandon the nest and visit distant areas(up to 500 km)for long periods(60.5±6.2 days).Breeding outcome did not influence the departure date of autumn migration,suggesting that failed breeders used this period for exploratory movements but not for advancing the onset of *** exploratory movements may be functional to prospect and inform settlement decisions in failed breeders in search of new breeding opportunities and may be particularly important in migratory species,which generally have a limited period to gather information prior to autumn *** study demonstrates the need to investigate seasonal movements in different populations and the potential importance of pros-pectingpost-breeding movements for long-distance migratory species.

关键词： animal movement biologging conservation Coracidae Mediterranean nest-box population monitoring prospecting movements reproduction.

A machine learning driven 3D+1D model for efficient characterization of proton exchange membrane fuel cells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy and AI 2024年第3期17卷 281-294页

作者： Yuwei Pan Haijun Ruan Billy Wu Yagya N.Regmi Huizhi Wang Nigel P.Brandon Department of Earth Science and Engineering Imperial College LondonLondon SW72AZUK Dyson School of Design Engineering Imperial College LondonLondon SW72AZUK Centre for E-Mobility and Clean Growth Coventry UniversityCoventry CV15FBUK Manchester Fuel Cell Innovation Centre Department of Natural SciencesManchester Metropolitan UniversityManchester M15GDUK Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

The computational demands of 3D continuum models for proton exchange membrane fuel cells remain substantial. One prevalent approach is the hierarchical model combining a 2D/3D flow field with a 1D sub-model for the catalyst layers and membrane. However, existing studies often simplify the 1D domain to a linearized 0D lumped model, potentially resulting in significant errors at high loads. In this study, we present a computationally efficient neural network driven 3D+1D model for proton exchange membrane fuel cells. The 3D sub-model captures transport in the gas channels and gas diffusion layers and is coupled with a 1D electrochemical sub-model for microporous layers, membrane, and catalyst layers. To reduce computational intensity of the full 1D description, a neural network surrogates the 1D electrochemical sub-model for coupling with the 3D domain. Trained by model-generated large synthetic datasets, the neural network achieves root mean square errors of less than 0.2%. The model is validated against experimental results under various relative humidities. It is then employed to investigate the nonlinear distribution of internal states under different operating conditions. With the neural network operating at 0.5% of the computing cost of the 1D sub-model, the hybrid model preserves a detailed and nonlinear representation of the internal fuel cell states while maintaining computational costs comparable to conventional 3D+0D models. The presented hybrid data-driven and physical modeling framework offers high accuracy and computing speed across a broad spectrum of operating conditions, potentially aiding the rapid optimization of both the membrane electrode assembly and the gas channel geometry.

关键词： Proton exchange membrane fuel cell Hierarchical model Neural network Hybrid model

On the analytical solution of transient friction in channel flows

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1447-1466页

作者： F.J.GARCíA-GARCíA P.FARINAS-ALVARINO Department of Naval&Industrial Engineering Polytechnic School of EngineeringUniversity of A CorunaCampus Industrial de FerrolFerrol 15403A CorunaSpain Integraciones Técnicas de Seguridad S.A.Pol.Ind.Espiritu SantoC/Nobel15Cambre 15650A CorunaSpain

The transient friction in channel mean flows is the sum of two contributions,i.e.,the underlying laminar flow(ULF)and the purely turbulent component(PTC),and the contributions are analyzed separately by theoretical *** is found that,the transient friction may be higher or remarkably lower than that in equal-Reynolds number steady-state *** universal time constant for plane-parallel laminar flows is reported,and the role of the time constant in a turbulent mean flow is *** is shown that the time constant is related to the turbulence's frozen ***,a study of the logarithmic layer during the transient flow is accomplished,which shows that the logarithmic layer is destroyed.

关键词： transient friction transient flow unsteady channel flow

Effect of the Filling Liquid Ratio on the Thermal Performance of a Novel Thermal Diode with Wick

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第2期33卷 396-407页

作者： LI Zhiyong MING Tingzhen ZHANG Heyu ZHAO Sitong WANG Qinggang CAI Cunjin YIN Kui FANG Yueping WU Yongjia School of Civil Engineering and Architecture Wuhan University of TechnologyWuhan430070China Sanya Science and Education Innovation Park Wuhan University of TechnologySanya572004China Deparment of Four Station Logistics AcademyXuzhou221000China School of Energy Construction and EnvironmentCoventry UniversityPriory StreetCoventryCV15FBUK

The application of thermal diodes,which allow heat to flow more readily in one direction than the other,is an important way to reduce energy consumption in buildings and enhance the battery heat dissipation of electric *** on various factors including the specific design,materials used,and operating conditions,the convective thermal diode can exhibit the best thermal rectification effect in intended applications compared to the other thermal *** this study,a novel convective thermal diode with a wick was proposed based on the phase change heat transfer *** design takes advantage of both capillary forces provided by the wick and gravity to achieve enhanced unidirectional heat transfer performance for the designed convective thermal *** effect of the filling liquid ratio on the thermal performance of the thermal diode was experimentally investigated,which was in good agreement with the theoretical *** research findings showed that with an optimal liquid filling ratio of 140%,the thermal diode with a wick can achieve a better thermal rectification ratio when subjected to a lower heating power,and the maximum thermal rectification ratio of 21.76 was experimentally achieved when the heating power of the thermal diode was 40 W.

关键词： filling liquid ratio thermal diode wick structure gravity

Anti-methanogenic potential of seaweeds and seaweed-derived compounds in ruminant feed:current perspectives,risks and future prospects

在线全文

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2024年第2期15卷 463-489页

作者： Ailbhe McGurrin Julie Maguire Brijesh K.Tiwari Marco Garcia-Vaquero Section of Food and Nutrition School of Agriculture and Food ScienceUniversity College DublinDublin 4BelfieldIreland TEAGASC Food Research CentreDublin 15AshtownIreland Bantry Marine Research Station Ltd BantryCo.CorkP75 AX07GearhiesIreland

With methane emissions from ruminant agriculture contributing 17%of total methane emissions worldwide,there is increasing urgency to develop strategies to reduce greenhouse gas emissions in this *** of the proposed strategies is ruminant feed intervention studies focused on the inclusion of anti-methanogenic compounds which are those capable of interacting with the rumen microbiome,reducing the capacity of ruminal microorganisms to produce ***,seaweeds have been investigated for their ability to reduce methane in ruminants in vitro and in vivo,with the greatest methane abatement reported when using the red seaweed Asparagopsis taxiformis(attributed to the bromoform content of this species).From the literature analysis in this study,levels of up to 99%reduction in ruminant methane emissions have been reported from inclusion of this seaweed in animal feed,although further in vivo and microbiome studies are required to confirm these results as other reports showed no effect on methane emission resulting from the inclusion of seaweed to basal *** review explores the current state of research aiming to integrate seaweeds as anti-methanogenic feed additives,as well as examining the specific bioactive compounds within seaweeds that are likely to be related to these *** effects of the inclusion of seaweeds on the ruminal microbiome are also reviewed,as well as the future challenges when considering the largescale inclusion of seaweeds into ruminant diets as anti-methanogenic agents.

关键词： Asparagopsis Bromoform Methanogenesis Phlorotannin Saponin Tannin

Effective thermal conductivity estimation using a convolutional neural network and its application in topology optimization

在线全文

学校读者我要写书评

暂无评论

Energy and AI 2024年第1期15卷 236-247页

作者： Andre Adam Huazhen Fang Xianglin Li Department of Mechanical Engineering University of Kansas1530 W 15th St.Lawrence66045KSUSA Department of Mechanical Engineering and Materials Science Washington University in St.LouisOne Brookings DriveSt.Louis63130MOUSA

Topology optimization of heterogeneous structures can find significant use in a wide range of applications,and its fabrication has been made possible by recent advances in additive ***,the optimization procedure is computationally expensive,as each structural update requires the re-evaluation of the *** computational time is the major limiting factor in large-scale and complex structural *** this study,a convolutional neural network(CNN)model for predicting effective thermal conductivity inspired by the VGG networks is *** using 130,000 unique binary images,the model achieves high predictive ***,it shows a mean absolute percent error(MAPE)of 0.35%in testing when the thermal conductivity of the solid is ten times larger than the fluid,and when the thermal conductivities assigned are that of aluminum and water,the MAPE is 2.35%.The prediction time is 15 ms for a single image with 128×128 pixels,which is 3 to 5 orders of magnitude faster than a finite volume *** employed in topology optimization,the CNN retains a MAPE between 0.67%and 11.8%for different *** CNN model correctly predicts trends in effective thermal conductivity and improves the structure to close proximity of a theoretical maximum in all cases.

关键词： Machine learning Effective thermal conductivity Convolutional neural network VGG Numerical heat transfer Topology optimization

Highly-sensitive wafer-scale transfer-free graphene MEMS condenser microphones

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2024年第1期10卷 267-275页

作者： Roberto Pezone Sebastian Anzinger Gabriele Baglioni Hutomo Suryo Wasisto Pasqualina M.Sarro Peter G.Steeneken Sten Vollebregt Laboratory of Electronic Components Technology and Materials(ECTM)Department of MicroelectronicsDelft University of TechnologyDelftThe Netherlands Infineon Technologies AG Am Campeon 1-15Neubiberg 85579Germany Kavli Institue of Nanoscience Department of Quantum NanoscienceDelft University of TechnologyDelftthe Netherlands Department of Precision and Microsystems Engineering(PME) Delft University of TechnologyDelftThe Netherlands

Since the performance of micro-electro-mechanical system(MEMS)-based microphones is approaching fundamental physical,design,and material limits,it has become challenging to improve *** works have demonstrated graphene’s suitability as a microphone *** potential for achieving smaller,more sensitive,and scalable onchip MEMS microphones is yet to be *** address large graphene sizes,graphene-polymer heterostructures have been proposed,but they compromise performance due to added polymer mass and *** work demonstrates the first wafer-scale integrated MEMS condenser microphones with diameters of 2R=220-320μm,thickness of 7 nm multi-layer graphene,that is suspended over a back-plate with a residual gap of 5μ*** microphones are manufactured with MEMS compatible wafer-scale technologies without any transfer steps or polymer layers that are more prone to contaminate and wrinkle the *** designs,all electrically integrated are fabricated and characterized allowing us to study the effects of the introduction of a back-plate for capacitive *** devices show high mechanical compliances C_(m)=0.081-1.07μmPa^(−1)(10-100×higher than the silicon reported in the state-of-the-art diaphragms)and pull-in voltages in the range of 2-9.5 *** addition,to validate the proof of concept,we have electrically characterized the graphene microphone when subjected to sound *** estimated sensitivity of S_(1kHz)=24.3-321 mV Pa^(−1)for a V_(bias)=1.5 V was determined,which is 1.9-25.5×higher than of state-of-the-art microphone devices while having a~9×smaller area.

关键词： transfer plate approaching