检索结果-南通市图书馆

Primary and secondary control in DC microgrids: a review

维普期刊数据库评论

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 2019年第2期7卷 227-242页

作者： fei GAO Ren KANG Jun cao Tao YANG Department of Engineering Science University of OxfordOxfordUK Mixergy OxfordUK School of Geography Geology and the EnvironmentKeele UniversityKeeleUK Department of Electric and Electronic Engineering The University of NottinghamNottinghamUK

With the rapid development of power electronics technology, microgrid(MG) concept has been widely accepted in the field of electrical engineering. Due to the advantages of direct current(DC)distribution systems such as reduced losses and easy integration with energy storage resources, DC MGs have drawn increasing attentions nowadays. With the increase of distributed generation, a DC MG consisting of multiple sources is a hot research topic. The challenge in such a multi-source DC MG is to provide voltage support and good power sharing performance. As the control strategy plays an important role in ensuring MG’s power quality and efficiency, a comprehensive review of the state-of-art control approaches in DC MGs is necessary. This paper provides an overview of the primary and secondary control methods under the hierarchical control architecture for DC MGs. Specifically,inner loop and droop control approaches in primary control are reviewed. Centralized, distributed and decentralized approach based secondary control is discussed in *** findings and future trends are also presented at last.

关键词： Primary control Secondary control DC microgrids Droop control Power sharing

Modeling the redshift and energy distributions of fast radio bursts

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2017年第2期17卷 22-28页

作者： Xiao-Feng cao Ming Xiao fei Xiao Department of Physics and Engineering Hubei University of Education Wuhan 430205 China

Abstract Fast radio bursts （FRBs） are one of the most mysterious astronomical phenomena nowadays. The identification of their origin requires more observations in the future and, importantly, deep un- derstandings of the existing observational data. By fitting the redshift and energy distributions of 15 Parkes FRBs, we try to derive their intrinsic energy function and the cosmic evolution of their burst rates. Specifically, while the energy function is assumed as usual to have a single-power-law form, the burst rates are considered to be proportional to the cosmic star formation rates by a redshift-dependent coefficient. Some plausible fittings are obtained, which indicate the power-law assumptions are feasible and effective. The values of the power-law indices could be used to independently constrain candidate FRB models, although parameter degeneracies still exist.

关键词： radio continuum general

Composite electrolytes with efficient Li^(+)transport across ceramic/polymer interface

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2023年第7期66卷 1879-1880页

作者： Jiayao Chen Xinyuan Shan Peng-fei cao State Key Lab of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China Institute of New Energy Material Chemistry School of Materials Science and EngineeringNankai UniversityTianjin 300350China

Over the past decades,solid electrolytes have re-emerged as promising candidates which replace flammable liquid electrolytes for a safe,energy-dense,and reversible storage of electrochemical energy in batteries[1].However,as the main distinct families of solid electrolytes,both polymer and ceramic electrolytes have their individual disadvantages in ionic conductivity,mechanical robustness,and interfacial resistance.

关键词： ceramic polymer interface

Deformation and damage properties of rock-like materials subjected to multi-level loading-unloading cycles

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2023年第7期15卷 1768-1776页

作者： Zhizhen Liu Ping cao Qingxiong Zhao Rihong cao fei Wang Yellow River Laboratory Zhengzhou UniversityZhengzhou450001China School of Resource and Safety Engineering Central South UniversityChangsha410083China School of Engineering University of WarwickCoventryCV47ALUK

In the process of engineering construction such as tunnels and slopes,rock mass is frequently subjected to multiple levels of loading and unloading,while previous research ignores the impact of unloading rate on the stability of rock mass.A number of uniaxial multi-level cyclic loading-unloading experiments were conducted to better understand the effect of unloading rate on the deformation behavior,energy evolution,and damage properties of rock-like *** experimental results demonstrated that the unloading rate and relative cyclic number clearly influence the deformation behavior and energy evo-lution of rock-like *** particular,as the relative cyclic number rises,the total strain and reversible strain both increase linearly,while the total energy density,elastic energy density,and dissipated energy density all rise *** contrast,the irreversible strain first decreases quickly,then stabilizes,and finally rises *** the unloading rate increases,the total strain and reversible strain both increase,while the irreversible strain *** dissipated energy damage was examined in light of the aforementioned experimental *** accuracy of the proposed damage model,which takes into account the impact of the unloading rate and relative cyclic number,is then confirmed by examining the consistency between the model predicted and the experimental *** proposed damage model will make it easier to foresee how the multi-level loading-unloading cycles will affect the rock-like materials.

关键词： Incremental cyclic loading-unloading Unloading rate Strain characteristics Energy evolution Damage model

A Novel Plane-Based Control Bus Design with Distributed Registers in 3D NAND Flash Memories

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2022年第4期31卷 647-651页

作者： cao Huamin WANG Qi LIU fei HUO Zongliang Institute of Microelectronics Chinese Academy of Science College of Microelectronics University of Chinese Academy of Sciences Yangtze Memory Technologies Company Ltd.

This work presents a novel plane-based area-saving control bus design with distributed registers in 3D NAND flash memory. 99.47% control signal routing wires are reduced compared to the conventional control circuit design. Independent multi-plane read is compatible with the existing read operations thanks to the register addresses are reasonably assigned. Furthermore,power-saving register group address-based plane gating scheme is proposed which saves about 2.9 m W bus toggling power. A four-plane control bus design with 20Kbits registers has been demonstrated in field programmable gate array tester. The results show that the planebased control bus design is beneficial to high-performance3D NAND flash memory design.

关键词： Plane-based control bus design Distributed register Independent multi-plane read Plane gating 3D NAND flash memory

Separation of tungsten and molybdenum with solvent extraction using functionalized ionic liquid tricaprylmethylammonium bis(2,4,4-trimethylpentyl)phosphinate

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2021年第11期28卷 1769-1776页

作者： fei cao Wei Wang De-zhou Wei Wen-gang Liu School of Resource and Civil Engineering Northeastern UniversityShenyang 110819China Zhengzhou Institute of Multipurpose Utilization of Mineral Resources CAGSZhengzhou 450006China Key Laboratory for Polymetallic Ores’Evaluation and Utilization MNRZhengzhou 450006China

Functionalized ionic liquids(FILs)as extractants were employed for the separation of tungsten and molybdenum from a sulfate solution for the first *** effects of initial pH,extractant concentration,metal concentrations in the feed were comprehensively *** results showed that tricaprylmethylammonium bis(2,4,4-trimethylpentyl)phosphinate([A336][Cyanex272])could selectively extract W over Mo at an initial pH value of 5.5;the best separation factorβ_(W/Mo) of 25.61 was obtained for a solution with low metal concentrations(WO3:2.49 g/L,Mo:1.04 g/L).The[A336][Cyanex272]system performed effectively for solutions of different W/Mo molar ratios and different metal ion concentrations in the *** chemical reaction between[A336][Cyanex272]and W followed the ion association mechanism,which was further proved by the Fourier-transform infrared(FTIR)spectra of loaded[A336][Cyanex272]and the free *** stripping experiments indicated that 95.48%W and 100.00%Mo were stripped using a 0.20 mol/L sodium hydroxide ***,the selective extractions of W and Mo from two synthetic solutions of different high metal concentrations were obtained;the separation factorβW/Mo reached 23.24 and 17.59 for the first and second solutions,*** results suggest the feasibility of[A336][Cyanex272]as an extractant for the separation of tungsten and molybdenum.

关键词： tungsten molybdenum ionic liquid separation solvent extraction

Time-domain Spectral Finite Element Method for Wave Propagation Analysis in Structures with Breathing Cracks

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2020年第6期33卷 812-822页

作者： Zexing Yu Chao Xu fei Du Shancheng cao Liaiigxian Gu School of Astronautics Northwestern Polytechnic UniversityXVan 710072China

Guided waves are generally considered as a powerful approach for crack detection in structures,which are commonly investigated using the finite element method(FEM).However,the traditional FEM has many disadvantages in solving wave propagation due to the strict requirement of mesh *** tackle this issue,this paper proposes an efficient time-domain spectral finite element method(SFEM)to analyze wave propagation in cracked structures,in which the breathing crack is modeled by definiiig the spectral gap ***,novel orthogonal polynomials and Gauss-Lobatto-Legendre quadrature rules are adopted to construct the spectral ***,a separable hard contact is utilized to simulate the breathing ***,a comparison of the numerical results between the FEM and the SFEM is conducted to demonstrate the high efficiency and accuracy of the proposed *** on the developed SFEM,the nonlinear features of waves and influence of the incident mode are also studied in detail,which provides a helpful guide for a physical understanding of the wave propagation behavior in structures with breathing cracks.

关键词： Time-domain spectral finite element method Contact nonlinearity Gap element Breathing crack

Influence of Endwall Air Injection with Discrete Holes on Corner Separation of a Compressor Cascade

维普期刊数据库评论

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 Thermal Science 2021年第5期30卷 1684-1704页

作者： cao Zhiyuan GAO Xi ZHANG Xiang ZHANG fei LIU Bo School of Power and Energy Northwestern Polytechnical UniversityXi’an710072China

The aim of this study is to reveal the influence mechanism of endwall air injection with distributed holes on the corner separation of a highly loaded compressor cascade,so as to promote the application of injection in ***-hole and double-hole endwall injection schemes featuring different axial locations,pitchwise locations,injection mass rates and injection directions,were designed and *** showed that the corner separation was eliminated by endwall injection;the optimal single-hole injection scheme achieved an endwall loss coefficient reduction of 29.7%,with injection coefficient as low as 0.48%.The optimal axial location of single-hole endwall injection was at 82%axial chord,being the center of corner ***,as injection hole was located at upstream of it,endwall injection resulted in severer corner *** mid-span flow field was deteriorated after endwall injection,which was due to 3D flow effects,i.e.,AVDR(axial velocity density ratio)effect and low-momentum fluid spanwise migration *** optimal injection was achieved at low injection angle and from close to the suction surface on ***-hole injection exhibited inferior performance compared with single-hole,which was due to the interaction of the two injection streams and mixing of injection streams with the bulk stream.

关键词： compressor cascade corner separation flow control air injection endwall discrete hole injection

Effects of Squealer Geometry of Turbine Blade Tip on the Tip-Leakage Flow and Loss

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2021年第4期30卷 1376-1387页

作者： ZENG fei ZHANG Weihao WANG Yufan cao Xia ZOU Zhengping National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics School of Energy&Power EngineeringBeihang UniversityBeijing 100191China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

The effective control of the tip-leakage flow and loss is of great significance to improve the aerodynamic performance of the *** this paper,the evolution mechanism of tip-leakage flow in a transonic high pressure turbine with a squealer tip is investigated with numerical simulation *** impacts of squealer geometric,such as the inclined pressure side rim and squealer rim width,on the vortex structure in the gap and tip-leakage loss are *** results show that the scraping vortex inside the cavity plays the role of aero-labyrinth seal,and forms interlocking sealing labyrinth structure with the rims on both sides,which has an effective sealing effect on the tip-leakage *** inclined pressure side squealer rim inhibits the development of the pressure side squealer corner vortex,which is beneficial to expand the influence range of the scraping vortex and enhance the sealing effect on the tip-leakage *** increase of the suction side squealer rim width reduces the effective flow area at the gap exit,which is conducive to reduction of the tip-leakage flow rate and tip-leakage ***,the increase of the pressure side squealer rim width strengthens the pressure side squealer corner vortex and limits the development space of the scraping vortex,causing the adverse effects on the control of tip-leakage flow.

关键词： turbine squealer tip tip-leakage flow squealer width tip-leakage loss