检索结果-南通市图书馆

Journal of Hydrodynamics 2024年第1期36卷 184-201页

作者： Xiao-qi Jia Shuai-kang Zhang Zu-chao zhu Key Laboratory of Fluid Transmission Technology of Zhejiang Province Zhejiang Sci-Tech UniversityHangzhou310018China

To reveal the cavitation forms of tip leakage vortex(TLV)of the axial flow pump and the flow mechanism of the flow field,this research adopts the partially-averaged Navier-Stokes(PANS)model to simulate the cavitation values of an axial flow pump,followed by experimental *** experimental result shows that compared with the shear stress transport(SST)k-ωmodel,the PANS model significantly reduces the eddy viscosity of the flow field to make the vortex structure clearer and allow the turbulence scale to be more robustly *** cavitation area within the axial flow pump mainly comprises of TLV cavitation,clearance cavitation and tip leakage flows combined effect of triangular cloud cavitation *** formation and development of cavitation are accompanied by the formation and evolution of vortex,and variations in vortex structure also generate and promote the development of *** addition,an in-depth analysis of the relationship between the turbulent kinetic energy(TKE)transport equation and cavitation patterns was also conducted,finding that the regions with relatively high TKE are mainly distributed around gas/liquid boundaries with serious cavitation and evident gas-liquid *** phenomenon is mainly attributed to the combined effect of the pressure action term,stress diffusion term and TKE production term.

关键词： Cavitation axial flow pump tip leakage vortex(TLV) partially-averaged Navier-Stokes(PANS)model turbulent kinetic energy(TKE)

Allocating redundancy,maintenance and spare parts for minimizing system cost under decentralized repairs

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 Engineering Management 2024年第3期11卷 377-395页

作者： Tongdan JIN Shubin si Wenjin zhu Ingram School of Engineering Texas State UniversitySan MarcosTX 78666USA School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Industrial Engineering and Intelligent Manufacturing(Ministry of Industry and Information Technology) Xi’an 710072China

Reliability-redundancy allocation,preventive maintenance,and spare parts logistics are crucial for achieving system reliability and availability *** methods often concentrate on specific scopes of the system’s *** paper proposes a joint redundancymaintenance-inventory allocation model that simultaneously optimizes redundant component,replacement time,spares stocking,and repair *** reliability and availability criteria,our objective is to minimize the system’s lifetime cost,including design,manufacturing,and operational *** develop a unified system availability model based on ten performance drivers,serving as the foundation for the establishment of the lifetimebased resource allocation *** renewal theory is employed to estimate spare part demand from proactive and corrective replacements.A bisection algorithm,enhanced by neighborhood exploration,solves the complex mixed-integer,nonlinear optimization *** numerical experiments show that component redundancy is preferred and necessary if one of the following situations occurs:extremely high system availability is required,the fleet size is small,the system reliability is immature,the inventory holding is too costly,or the handson replacement time is *** joint allocation model also reveals that there exists no monotonic relation between spares stocking level and system availability.

关键词： system availability installed base decentralized repair redundancy-maintenance-inventory model superimposed renewal process

The Cult of Mazu in Hainan,China and Among Vietnamese Hainanese Diaspora:A Comparative Study of Mazu Culture

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Cultural and Religious Studies 2024年第1期12卷 42-47页

作者： zhu si YOU qi-Dongmeng Graduate Academy of Social Sciences HanoiVietnam Vietnam Academy of Social Sciences HanoiVietnam Hainan Normal University HaikouChina

The cult of Mazu is a common folk belief in China and *** from the Song and Yuan Dynasties,particularly during the Ming and qing Dynasties,the cult of Mazu spread to Vietnam through maritime trade and migration from coastal regions of *** centuries of integration and development,it evolved into its own cultural system of Mazu worship,becoming an important component of Vietnamese folk ***,China,as a crucial supply station on the Maritime silk Road,has close connections with the transmission of Mazu culture to *** paper adopts field investigations and literature research methods to explore the Mazu worship and culture in Hainan,China,and the qiongfu Assembly Halls in Vietnam.

关键词： Mazu worship and culture Hainan Vietnamese Hainanese diaspora comparison

High-entropy design boosts dielectric energy storage

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第8期43卷 4013-4015页

作者： qiu-Ying Xia He zhu si Lan Yang Ren Herbert Gleiter Institute of Nanoscience School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China Department of Physics City University of Hong KongHong Kong999077China

Dielectric capacitors are vital for advanced electronic and electrical power systems due to their impressive power density and ***,a persistent challenge has been enhancing their energy densities while maintaining high *** in Science,a novel high-entropy design for relaxor ferroelectric materials has been proposed,promising significant improvements in both energy density and efficiency for multilayer dielectric ceramic *** the crucial role of high-entropy design in energy storage materials and devices,this highlight focuses on interpreting the progress and significance of this innovative work.

关键词： ceramic dielectric energy

Microfluidic preparation of surfactant-free ultrafine DAAF with tunable particle size for insensitive initiator explosives

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第9期39卷 42-52页

作者： Bo Yang Rui Li Wei Cao si-min He Jincan zhu qi Wu Heng Ding Jin Chen Weimiao Wang Zhiqiang qiao Xiaodong Li Guangcheng Yang Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China Southwest University of Science and Technology Mianyang 621010China School of Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China

High purity and ultrafine DAAF(u-DAAF)is an emerging insensitive charge in *** there are many ways to obtain u-DAAF,developing a preparation method with stable operation,accurate control,good quality consistency,equipment miniaturization,and minimum manpower is an inevitable requirement to adapt to the current social technology development *** reported is the microfluidic preparation of u-DAAF with tunable particle size by a passive swirling *** the guidance of recrystallization growth kinetics and mixing behavior of fluids in the swirling microreactor,the key parameters(liquid flow rate,explosive concentration and crystallization temperature)were screened and optimized through screening *** the condition that no surfactant is added and only experimental parameters are controlled,the particle size of recrystallized DAAF can be adjusted from 98 nm to 785 nm,and the corresponding specific surface area is 8.45 m^(2)·g^(-1)to 1.33 m^(2)·g^(-1).In addition,the preparation method has good batch stability,high yield(90.8%-92.6%)and high purity(99.0%-99.4%),indicating a high practical application *** explosion derived flyer initiation tests demonstrate that the u-DAAF shows an initiation sensitivity much lower than that of the raw DAAF,and comparable to that of the refined DAAF by conventional spraying crystallization *** study provides an efficient method to fabricate u-DAAF with narrow particle size distribution and high reproducibility as well as a theoretical reference for fabrication of other ultrafine explosives.

关键词： Microfluidic preparation Screening crystallization conditions Narrow particle size distribution Low initiation sensitivity Ultrafine DAAF

Grapevine-like high entropy oxide composites boost high-performance lithium sulfur batteries as bifunctional interlayers

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2024年第3期9卷 565-572页

作者： Huarong Fan Yubing si Yiming Zhang Fulong zhu Xin Wang Yongzhu Fu College of Chemistry and Center of Green Catalysis Zhengzhou UniversityZhengzhou450001China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu611731China

Lithium-sulfur batteries(LSBs)with high energy densities have been demonstrated the potential for energy-intensive demand ***,their commercial applicability is hampered by hysteretic electrode reaction kinetics and the shuttle effect of lithium polysulfides(LiPSs).In this work,an interlayer consisting of high-entropy metal oxide(Cu_(0.7)Fe_(0.6)Mn_(0.4)Ni_(0.6)Sn_(0.5))O_(4) grown on carbon nanofibers(HEO/CNFs)is designed for *** CNFs with highly porous networks provide transport pathways for Li^(+) and e^(-),as well as a physical sieve effect to limit LiPSs *** particular,the grapevine-like HEO nanoparticles generate metal-sulfur bonds with LiPSs,efficiently anchoring active *** unique structure and function of the interlayer enable the LSBs with superior electrochemical performance,i.e.,the high specific capacity of 1381 mAh g^(-1) at 0.1 C and 561 mAh g^(-1) at 6 *** work presents a facile strategy for exploiting high-performance LSBs.

关键词： Electrospun carbon nanofibers Grapevine-like morphology Hierarchical physical sieve effect High-entropy induced chemisorption Lithium-sulfur battery

Ferrihydrite transformation impacted by coprecipitation of lignin:Inhibition or facilitation?

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第5期139卷 23-33页

作者： Lin Liu Zhihui Yang Weichun Yang Wen Jiang qi Liao Mengying si Feiping Zhao School of Metallurgy and Environment Central South UniversityChangsha 410083China Chinese National Engineering Research Center for Control&Treatment of Heavy Metal Pollution(CNERC-CTHMP) Changsha 410083China

Lignin is a common soil organic matter that is present in soils,but its effect on the transformation of ferrihydrite(Fh)remains *** matter is generally assumed to inhibit Fh ***,lignin can reduce Fh to Fe(Ⅱ),in which Fe(Ⅱ)-catalyzed Fh transformation ***,the effects of lignin on Fh transformation were investigated at 75℃ as a function of the lignin/Fh mass ratio(0-0.2),pH(4-8)and aging time(0-96 hr).The results of Fh-lignin samples(mass ratios=0.1)aged at different pH values showed that for Fh-lignin the time of Fh transformation into secondary crystalline minerals was significantly shortened at pH 6 when compared with pure Fh,and the Fe(Ⅱ)-accelerated transformation of Fh was strongly dependent on *** pH 6,at low lignin/Fh mass ratios(0.05-0.1),the time of secondary mineral formation decreased with increasing lignin *** high lignosulfonate-content material(lignin:Fh=0.2),Fh did not transform into secondary minerals,indicating that lignin content plays a major role in Fh *** addition,lignin affected the pathway of Fh transformation by inhibiting goethite formation and facilitating hematite *** effect of coprecipitation of lignin on Fh transformation should be useful in understanding the complex iron and carbon cycles in a soil environment.

关键词： Ferrihydrite transformation Lignin Hematite Goethite Fe(Ⅱ)-catalyzed Reactive Fe(Ⅲ)species

Converting an O-vacancy-rich oxide into a multifunctional separator modifier for long-lifespan lithium metal batteries

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第10期97卷 371-378,I0007页

作者： Juntao si Xiaoying Li Yixuan Li Kuo Cao Yiran zhu Chunhua Chen CAS Key Laboratory of Precision and Intelligent Chemistry Department of Materials Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026AnhuiChina

The lithium metal anode is hailed as the desired "holy grail" for the forthcoming generation of highenergy-density batteries,given its astounding theoretical capacity and low ***,the formation and growth of dendrites seriously compromise battery life and ***,an yttriastabilized bismuth oxide(YSB) layer is fabricated on the polypropylene(PP) separator,where YSB reacts with Li anode in-situ in the cell to form a multi-component composite interlayer consisting of Li_(3)Bi,Li_(2)O,and Y_(2)O_(3).The interlayer can function not only as a redistributor to regulate Li^(+) distribution but also as an anion adsorber to increase the Li^(+) transference number from 0.37 to 0.79 for suppressing dendrite nucleation and ***,compared with the cell with a baseline separator,those with modified separators exhibit prolonged lifespan in both Li/Li symmetrical cells and Li/Cu ***,the full cells coupled with ultrahigh-loading LiFePO_(4) display an excellent cycling performance of 1700 cycles with a high capacity retention of ~80% at 1 C,exhibiting great potential for practical *** work provides a feasible and effective new strategy for separator modification towards building a much-anticipated dendrite-free Li anode and realizing long-lifespan lithium metal batteries.

关键词： Lithium metal battery Separator Dendrite-free Multifunctional interlayer Conversion-alloying reaction

Exploring Mazu Worship at Fujian Assembly Hall in Hoi An,Vietnam

在线全文

学校读者我要写书评

暂无评论

Cultural and Religious Studies 2024年第1期12卷 60-63页

作者： zhu si YOU qi-Dongmeng Graduate Academy of Social Sciences HanoiVietnam Vietnam Academy of Social Sciences HanoiVietnam Hainan Normal University HaikouChina

Hoi An Ancient Town in Vietnam is not only a UNESCO(United Nations Educational,Scientific,and Cultural Organization)World Heritage site but also a convergence point of traditional and modern *** its historical transitions,the cultural heritage of Hoi An Ancient Town has been well preserved and developed,and the worship of Mazu,an essential component of Hoi An’s culture,is no *** far as is known,Hoi An in central Vietnam houses the most Mazu temples,including the Chung Wah Hall,the Guangzhou Assembly Hall,the Fujian Assembly Hall,the Teochew Assembly Hall,and the Hainan Assembly Hall,among others,with the Fujian Assembly Hall being the most vibrant center of Mazu *** study employs field surveys and literature research to explore the Mazu worship practices at the Fujian Assembly Hall in Hoi An,Quang Nam Province,Vietnam.

关键词： Mazu worship Hoi An Vietnam Chinese community

Hydrogen-rich surface of MoC catalysts for efficient CO_(2) hydrogenation induced by a coupled hydrogen donator

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第8期17卷 7762-7767页

作者： Dong Xu si-Yuan Xia qi-Yuan Li Jie-Sheng Chen Xin-Hao Li School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesShanghai Jiao Tong UniversityShanghai 200240China

Direct CO_(2) hydrogenation offers an important strategy for promoting the global carbon balance,but high thermodynamic and kinetic stability of CO_(2) has restricted its applicability to only a handful of industrial ***,we introduce a proof-of-concept application of the electron-rich Pt surface to promote hydrogen donation for electron-rich MoC particles acting as hydrogen acceptors,thereby constructing hydrogen-rich surface of MoC active ***,the formed hydrogen-rich and electronrich surface could greatly decrease reaction activation energy to boost the efficient CO_(2) hydrogenation into formic acid over the MoC *** optimized MoC@NC/Pt-0.1(NC:nitrogen-doped carbon)catalyst exhibits a high turnover frequency(TOF)value of 1.2 h^(−1) at a lower temperature of 60℃and a TOF of 24.2 h^(−1) under standard reaction conditions widely used in the literature,exceeding 7 times of MoC@NC catalyst and surpassing the benchmark classical non-noble metal active center-based heterogeneous catalyst.

关键词： electron-rich Pt nanoparticles hydrogen donation hydrogen-rich MoC nanoparticles CO_(2) hydrogenation formic acid