检索结果-南通市图书馆

Miniaturized and highly sensitive fiber-optic Fabry–Perot sensor for mHz infrasound detection

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Photonics Research 2024年第5期12卷 969-978页

作者： PEIJIE WANG YUFENG PAN JIANGSHAN ZHANG JIE ZHAI DEMING LIU PING LU Wuhan National Laboratory for Optoelectronics(WNLO)and National Engineering Research center of next generation Internet Access system School of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan 430074China Optics Valley Laboratory Wuhan 430074China Department of Electronics and Information Engineering Huazhong University of Science and TechnologyWuhan 430074China

Infrasound detection is important in natural disasters monitoring,military defense,underwater acoustic detection,and other ***-optic Fabry–Perot(FP)acoustic sensors have the advantages of small structure size,long-distance detection,immunity to electromagnetic interference,and so *** size of an FP sensor depends on the transducer diaphragm size and the back cavity ***,a small transducer diaphragm size means a low ***,a small back cavity volume will increase the low cut-off frequency of the ***,it is difficult for fiber-optic FP infrasound sensors to simultaneously achieve miniaturization,high sensitivity,and extremely low detectable *** this work,we proposed and demonstrated a miniaturized and highly sensitive fiber-optic FP sensor for m Hz infrasound detection by exploiting a Cr-Ag-Au composite acoustic-optic transducer diaphragm and a MEMS technique-based spiral micro-flow *** use of the spiral micro-flow hole as the connecting hole greatly reduced the volume of the sensor and decreased the low-frequency limit,while the back cavity volume was not *** with the Cr-Ag-Au composite diaphragm,a detection sensitivity of-123.19 dB re 1 rad∕μPa at 5 Hz and a minimum detectable pressure(MDP)of1.2 mPa∕Hz^(1∕2)at 5 Hz were *** low detectable frequency can reach 0.01 Hz and the flat response range was 0.01–2500 Hz with a sensitivity fluctuation of±1.5 d ***,the size of the designed sensor was only 12 mm×Φ12.7 *** excellent characteristics make the sensor have great practical application prospects.

关键词： sound fiber cavity

Wide frequency phonons manipulation in Si nanowire by introducing nanopillars and nanoparticles

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第4期33卷 78-84页

作者：李亚涛刘英光李鑫李亨宣王志香张久意 Hebei Key Laboratory of Low Carbon and High Efficiency power generation technology North China Electric Power UniversityBaoding 071003China

The combination of different nanostructures can hinder phonons transmission in a wide frequency range and further reduce the thermal conductivity(TC).This will benefit the improvement and application of thermoelectric conversion,insulating materials and thermal barrier coatings,*** this work,the effects of nanopillars and Ge nanoparticles(GNPs)on the thermal transport of Si nanowire(SN)are investigated by nonequilibrium molecular dynamics(NEMD)*** analyzing phonons transport behaviors,it is confirmed that the introduction of nanopillars leads to the occurrence of lowfrequency phonons resonance,and nanoparticles enhance high-frequency phonons interface scattering and *** results show that phonons transport in the whole frequency range can be strongly hindered by the simultaneous introduction of nanopillars and *** addition,the effects of system length,temperature,sizes and numbers of nanoparticles on the TC are *** work provides useful insights into the effective regulation of the TC of nanomaterials.

关键词： resonant structure nanoparticles nanopillars phonon transport thermal conductivity

Effect of operational and geometric parameters on the hydrodynamics of a Wurster coater:A CFD-DEM study

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第2期85卷 62-76页

作者： Yinqiang Song Tuo Zhou Ruiqi Bai Man Zhang Hairui Yang Department of Energy and power Engineering Tsinghua UniversityBeijing100084China Key Laboratory for Thermal Science and power Engineering of Ministry of Education Tsinghua UniversityBeijing100084China State Key Laboratory of power system and generation Equipment Tsinghua UniversityBeijing100084China

A coupled CFD-DEM method was used to study the hydrodynamics of a Wurster ***,the CFD part of the model was validated by the accurate prediction of the pressure drops over a pseudo-2D fluidized bed under various gas *** effect of gas velocity,gap height,tube length and batch volume of the particles on the cycle time and the residence time of the particles was thoroughly *** central jet gas velocity ui was found to speed up the particle cycle but undermine the coating *** gas velocity at the horizontal transport zone u2 was able to promote the horizontal transport of the particles but should not be too high,otherwise,it would obstruct the normal falling back of the particles in the downward *** gap heights would decrease the coating efficiency but tube length had little impact on *** increment of batch volume would commonly abase the cycle time and the working efficiency under a given *** de-fluidization problem arose when the batch volume increased to 550 ***,this problem could be swept out by the optimization of u1 and *** a mixture of different sizes,the coarse particles enjoyed higher coating efficiency and could travel closer to the *** may shield the fine particles from getting enough coating liquids,and thus coarse particles and fine particles were not recommended to get coated in the same batch.

关键词： Numerical simulation CFD-DEM Wurster coater Hydrodynamics Cycle time Residence time

Security-constrained Transmission Maintenance Optimization Considering generation and Operational Risk Costs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern power systems and Clean Energy 2024年第3期12卷 767-781页

作者： Dan Xu Zhi Cai Qian Cheng Guodong Huang Jingyang Zhou Junjie Tang Beijing Key Laboratory of Research and system Evaluation of power Dispatching Automation technology China Electric Power Research InstituteBeijing 100192China State Key Laboratory of power Transmission Equipment&system Security and New technology Chongqing UniversityChongqing 400044China

With the large-scale integration of renewable energy,the traditional maintenance arrangement during the load valley period cannot satisfy the transmission demand of renewable energy ***,in a market-oriented operation mode,the power dispatching control center aims to reduce the overall power purchase cost while ensuring the security of the power ***,a security-constrained transmission maintenance optimization model considering generation and operational risk costs is proposed *** model is built on double-layer optimization framework,where the upper-layer model is used for maintenance and generation planning,and the lowerlayer model is primarily used to address the operational security risk arising from the random prediction error and N-1 transmission ***,a generation-maintenance iterative algorithm based on a defined cost feedback is included to increase solution *** cost is determined using long-term security-constrained unit commitment,and the operational risk cost is obtained using a double-layer N-1 risk assessment *** electrical correlation coupling coefficient is proposed for the solution process to avoid maintenance of associated equipment simultaneously,thereby improving model convergence *** IEEE 118-bus system is used as a test case for illustration,and test results suggest that the proposed model and algorithm can reduce the total cost of transmission maintenance and system operation while effectively improving the solution efficiency of the joint optimization model.

关键词： Transmission maintenance security-constrained unit commitment iterative algorithm cost feedback N−1 risk assessment

Convolution Neural Network-based Load Model Parameter Selection Considering Short-term Voltage Stability

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of power and Energy systems 2024年第3期10卷 1064-1074页

作者： Ying Wang Chao Lu Xinran Zhang School of technology Beijing Forestry UniversityBeijing 100083China State Key Laboratory of Control and Simulation of power system and generation Equipment Tsinghua UniversityBeijing 100084China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China IEEE

The recently proposed ambient signal-based load modeling approach offers an important and effective idea to study the time-varying and distributed characteristics of power ***,it also brings new *** the load model parameters of power loads can be obtained in real-time for each load bus,the numerous identified parameters make parameter application *** order to obtain the parameters suitable for off-line applications,load model parameter selection(LMPS)is first introduced in this ***,the convolution neural network(CNN)is adopted to achieve the selection purpose from the perspective of short-term voltage *** begin with,the field phasor measurement unit(PMU)data from China Southern power Grid are obtained for load model parameter identification,and the identification results of different substations during different times indicate the necessity of ***,the simulation case of Guangdong power Grid shows the process of LMPS,and the results from the CNNbased LMPS confirm its effectiveness.

关键词： Ambient signal CNN field PMU data load model parameter selection short-term voltage stability

Characteristics of Controlled Bridge Circuit and Its Application in Magnetic Field Induction Measurement

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and technology 2024年第4期29卷 1105-1117页

作者： Yanchu Li Qingqing Ding Mingchen Yan Jiyao Wang Jun Xu Xinzhou Dong Department of Electrical Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Control and Simulation of power system and generation Equipments Tsinghua UniversityBeijing 100084China School of Electrical and Electronic Engineering North China Electric Power UniversityBeijing 100096China

The article designs a new type of bridge circuit with a controlled source—when the resistance on the bridge arm of the controlled source bridge circuit meets the bridge balance condition, and the bridge branch contains only one Current-Controlled Current Source (CCCS), a Voltage-Controlled Current Source (VCCS), a Current-Controlled Voltage Source (CCVS), or a Voltage-Controlled Voltage Source (VCVS), the circuit is called a controlled bridge circuit, which has the characteristics of bridge balance. Due to the relationship between the controlled source and the bridge arm, the sensitivity of the components on the bridge is higher mathematically and logically. When applied to measurement, engineering, automatic control, and other fields, the controlled bridge circuit has higher control ac-curacy. Mathematical derivation and simulation results prove the correctness of the bridge balance conclusion and the special properties of this bridge when applied to the measurement field.

关键词： bridge bircuit bridge circuit applications bridge balanced condition controlled bridge circuit magnetic field induction measurement

Comparative study on the hydrogen storage performance of as-milled MgRENi rapid quenched alloy catalyzed by metal sulfides

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第5期12卷 2010-2023页

作者： Xiaoping Dong Zhaoqing Zhang Liying Yang Shenghai Xin Dandan Su Zhiyuan Li Department of Mechanical Design and Manufacture and Automation Hebei UniversityBaoding 071000PR China Baoding New Energy Vehicle power Engineering technology Research center Hebei UniversityBaoding 071002PR China Hebei technology Innovation center for Lightweight of New Energy Vehicle power system(Preparation) Hebei UniversityBaoding 071002PR China

The composites of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)as-quenched alloy and 3 wt.%M(M=CoS,CoS_(2),MoS_(2))catalyst were prepared by high-speed vibration ball *** effects of metal sulfides on the hydrogenation and dehydrogenation dynamics of alloys were *** results show that the as-milled composites contain a large number of amorphous embedded by a small amount of nanocrystals,and there are many point *** ball milling,the crystal grain size in the composites containing CoS is relatively larger,followed by CoS_(2)and MoS_(2)*** hydrogenation,the amorphous phase is crystallized to form Mg_(2)NiH_(4),YH_(3),Pr_(8)H_(18.96),Sm_(3)H_7,Mg,Co or Mo phases,however,Mg_(2)Ni,YH_(2),PrH_(2)and Ni_(3)Y phases appeared after *** maximum hydrogenation capacity of the composites containing CoS,CoS_(2)and MoS_(2)are 3.939,4.265 and 4.507 wt.%,*** hydrogenation saturation ratio of composite containing MoS_(2)is higher than that of the composites containing CoS and CoS_(2).The dehydrogenation activation energy of the composites containing CoS,CoS_(2)and MoS_(2)is 107.76,68.43 and 63.28 ***^(-1).H_(2).On the improvement of hydrogen storage performance of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)alloy,the catalytic effect of MoS_(2)sulfide is better than that of CoS_(2)sulfide,and which is better than CoS sulfide.

关键词： Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)as-quenched alloy CoS CoS_(2)and MoS_(2)sulfide Milling Activation energy Hydrogen storage dynamics

Precise control of page cache for containers

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第2期18卷 17-30页

作者： Kun WANG Song WU Shengbang LI Zhuo HUANG Hao FAN Chen YU Hai JIN National Engineering Research center for Big Data technology and system Services Computing Technology and System LabCluster and Grid Computing Lab School of Computer Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China

Container-based virtualization isbecoming increasingly popular in cloud computing due to its efficiency and *** isolation is a fundamental property of *** works have indicated weak resource isolation could cause significant performance degradation for containerized applications and enhanced resource ***,current studies have almost not discussed the isolation problems of page cache which is a key resource for *** leverage memory cgroup to control page cache ***,existing policy introduces two major problems in a container-based ***,containers can utilize more memory than limited by their cgroup,effectively breaking memory ***,the Os kernel has to evict page cache to make space for newly-arrived memory requests,slowing down containerized *** paper performs an empirical study of these problems and demonstrates the performance impacts on containerized *** we propose pCache(precise control of page cache)to address the problems by dividing page cache into private and shared and controlling both kinds of page cache separately and *** do so,pCache leverages two new technologies:fair account(f-account)and evict on demand(EoD).F-account splits the shared page cache charging based on per-container share to prevent containers from using memory for free,enhancing memory *** EoD reduces unnecessary page cache evictions to avoid the performance *** evaluation results demonstrate that our system can effectively enhance memory isolation for containers and achieve substantial performance improvement over the original page cache management policy.

关键词： page cache memory cgroup container isolation cloud computing

Answering reachability queries with ordered label constraints over labeled graphs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第1期18卷 105-117页

作者： Daoliang HE Pingpeng YUAN Hai JIN National Engineering Research center for Big Data technology and system Services Computing Technology and System LabCluster and Grid Computing LabSchool of Computer Science&TechnologyHuazhong University of Science and TechnologyWuhan 430074China

Reachability query plays a vital role in many graph analysis *** researches proposed many methods to efficiently answer reachability queries between vertex *** many real graphs are labeled graph,it highly demands Label-Constrained Reachability(LCR)query inwhich constraint includes a set of labels besides vertex *** researches proposed several methods for answering some LCR queries which require appearance of some labels specified in constraints in the *** that constraint may be a label set,query constraint may be ordered labels,namely OLCR(Ordered-Label-Constrained Reachability)queries which retrieve paths matching a sequence of ***,no solutions are available for ***,we propose DHL,a novel bloom filter based indexing technique for answering OLCR *** can be used to check reachability between vertex *** the answers are not no,then constrained DFS is ***,we employ DHL followed by performing constrained DFS to answer OLCR *** show that DHL has a bounded false positive rate,and it's powerful in saving indexing time and *** experiments on 10 real-life graphs and 12 synthetic graphs demonstrate that DHL achieves about 4.8-22.5 times smaller index space and 4.6-114 times less index construction time than two state-of-art techniques for LCR queries,while achieving comparable query response *** results also show that our algorithm can answer OLCR queries effectively.

关键词： graph ordered-label-constrained reachability partial index bloom filter query processing