检索结果-南通市图书馆

Numerical Study of Flow and Heat Transfer Characteristics of Shell-and-Tube Molten Salt Electric Heater with Circularly Perforated Baffles

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 2025年第1期34卷 24-33页

作者： LIN Yongjie ZHANG Cancan WU Yuting ZHANG Yi LU Yuanwei Key Laboratory of Heat Transfer and energy Conversion National User-Side Energy Storage Innovation Research and Development CenterBeijing University of Technology

Numerical simulations of the flow and heat transfer characteristics of four shell-and-tube molten salt electric heaters with different perforation rates was ***-and-tube electric heaters have the same geometry and tube arrangement,and all of them use single segmental baffles,but there exist four different baffle openings（φ）,i.e.,0%,2.52%,4.06%,and 6.31%.The results indicated that the reasonable baffle opening could significantly reduce the shell-side pressure drop,effectively decreasing the shell-side flow dead zone *** can eliminate the local high-temperature phenomenon on the surface of electric heating tubes,but the heat transfer coefficient is slightly *** perforated schemes significantly reduce shell-side pressure drop compared to the baseline solution without open *** particular,the φ=6.31% scheme exhibits the optimal performance among all the schemes,with a maximum reduction of up to 50.50% in shell-side pressure drop relative to the unopened holes *** heat transfer coefficient is the highest for φ=0%,exhibiting a range of5.26% to 5.73%,5.14% to 5.99%,and 7.31% to 8.54% higher than φ=2.52%,4.06%,and 6.31%,respectively,within the calculated *** composite index h/（Δp）1/3was higher for all open-hole solutions than that for the unopened-hole *** best overall performance was for φ=6.31%,which improved the composite index by15.29% to 17.18% over the unopened-hole solution.

关键词： molten salt electric heater perforated baffles heat transfer

Synergistically enhanced ORR and HER performance on Co-N-C coupled in-situ generated PtCo intermetallic

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of energy Chemistry 2025年第1期100卷 721-729页

作者： Guanyu Luo Min Song Lulu An Xiao Huang Qian Zhang Chenhao Zhang Tao Shen Shuang Wang Deli Wang Key Laboratory of Material Chemistry for energy Conversion and Storage (Huazhong University of Science and Technology) Ministry of Education School of Chemistry and Chemical Engineering Huazhong University of Science and Technology

Integrating multi-scale sites in a composite catalyst is vital to realize efficient ***,a synergistic composite catalyst consisting of Co atomic sites and in-situ generated PtCo intermetallic compounds （IMCs）(o-PtCo@CoNC) is proposed through Co pre-anchoring and subsequent impregnation-reduction *** loading of Co atoms provides a chance for in-situ generating PtCo ordered intermetallic *** remaining Co single atoms and PtCo IMCs construct synergistic electrocatalytic *** from the ordered structure,synergistic effect of Pt Co IMCs and Co single atoms,o-PtCo@CoNC exhibits excellent electrocatalytic performance for oxygen reduction reaction （ORR） and hydrogen evolution reaction （HER） with mass activity of 1.21 A mgPt-1（at 0.9 V） and5.70 A mgPt-1（at an overpotential of 100 mV）,***,o-PtCo@CoNC delivers negligible loss of half-wave potential and overpotential during long-term stability test in acid solutions,with 13 mV decay after 50,000 potential cycles for ORR and a 2.7 mV decay after 20,000 potential cycles for *** integration strategy of single-atomic sites coupled IMCs paves the way for enhancing the activity and durability of Pt-based electrocatalysts.

关键词： Synergistic effect Intermetallics Single atomic sites Oxygen reduction reaction Hydrogen evolution reaction

Free vibration and transient response of double curved beams connected by intermediate straight beams

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAEI H.GHANDVAR E.JUMAEV S.KHATIR T.CUONG-LE School of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for Engineering Application and Technology solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

关键词： Kinetic energy

High-selectivity electroreduction of low-concentration CO2 with large concentration fluctuation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2025年

作者： Mengyu Qi Yanbin Ma Chao Zhang Bingwei Li Xueqing Yang Zhaolin Shi Simeng Liu Changhua An Jiqing Jiao Tongbu Lu MOE International Joint Laboratory of Materials Microstructure Analysis and Testing CenterInstitute for New Energy Materials and Low Carbon TechnologiesSchool of Materials Science and EngineeringSchool of Chemistry and Chemical EngineeringTianjin University of Technology Key Laboratory of Advanced energy Materials Chemistry (Ministry of Education) Nankai University

Electrochemical CO2reduction reaction（CO2RR） has been regarded as one of the most promising solutions to achieving “zero carbon emission”. In most of the CO2RR-related studies, high-purity CO2has been employed as the feed gas; however, in practice, CO2is generally emitted in low concentrations, so it is of great significance to realize high-selectivity electroreduction of low-concentration CO2with large concentration fluctuation. In this work, we constructed a dual-active-site catalyst and successfully achieved CO2local enrichment and conversion for low-concentration CO2. Operando experiments reveal that the catalyst has one type of site for activating CO2and one type of site for binding the reaction intermediates. The dual-active-site catalyst displays a selectivity for formic acid consistently above 97% over a broad potential window（from-0.9 to-1.6 V ***）. Even when fed with a low-concentration CO2stream（volume ratio from 50% down to 10%）, the dual-active-site catalyst could display high activity and selectivity（>91%）. In particular, the selectivity is still above 85% when the CO2volume ratio is as low as 5%. This work offers a feasible route for converting low-concentration CO2via a synergistic effect for dual-active-site catalysts.

关键词：

Solar rooftop in India: Policies,challenges and outlook

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Green energy & Environment 2016年第2期1卷 129-137页

作者： Malti Goel Science & Technological solutions for Sustainable energy Future Climate Change Research Institute

Solar photovoltaic rooftop has emerged as a potential green technology to address climate change issues by reducing reliance on conventional fossil fuel based energy. With a strong commitment to increase the renewable sources based energy capacity to 175 GW by 2022, India has a target to install 100 GW of solar energy capacity. Of this 40 GW would be the share of grid connected solar PV rooftop. This paper examines global growth in solar energy, world's major rooftop installed capacity countries' policies and solar rooftop policy instruments in India. The current Indian goals, issues & challenges in achieving them and trends in further development are discussed.

关键词： Solar energy India Rooftop PV Policies Outlook

维普期刊数据库

Osmotic Pressure of Water in Nafion~

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2010年第4期15卷 385-390页

作者： Michael K.Budinski Adam Cook General Motors Company Electrochemical Energy Research Lab Honeoye Falls Trison Business solutions

Mechanical failure modes leading to cracks or breeches in proton exchange membrane fuel cells are driven by mechanical forces associated with swelling from water uptake and shrinkage from dehumidifi- cation. To determine the magnitude of compressive mechanical stress imposed by water swelling in a proton exchange fuel-cell membrane, the osmotic pressure of water in a perfluorosulfonic acid ionomer （Nation N 117） membrane was measured using a hydrostatic piston-cylinder device with an in-situ hydrophilic frit. Experiments indicate that hydrostatic stresses greater than 103.5 MPa are created in a membrane when swollen with water at 23℃ suggesting that pressure from water swelling can distort Nafion N 117-based structures as the osmotic pressure is of the same order of magnitude as the flow stress of Nation N 117.

关键词： osmotic pressure pinholes proton exchange membrane fuel-cell perfluorosulfonic acidionomer

维普期刊数据库

Body armour-New materials, new systems

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2019年第3期15卷 241-253页

作者： Ian G.Crouch Armour solutions

This is a very timely review of body armour materials and systems since new test standards are currently being written, or reviewed, and new, innovative products released. Of greatest importance, however, is the recent evolution, and maturity, of the Ultra High Molecular Weight Polyethylene fibres enabling a completely new style of system to evolve e a stackable system of Hard Armour Plates. The science of body armour materials is quickly reviewed with emphasis upon current understanding of relevant energy-absorbing mechanisms in fibres, fabrics, polymeric laminates and ceramics. The trend in ongoing developments in ballistic fibres is then reviewed, analysed and future projections offered. Weaknesses in some of the ceramic grades are highlighted as is the value of using cladding materials to improve the robustness, and multi-strike performance, of Hard Armour Plates. Finally, with the drive for lighter, and therefore smaller, soft armour systems for military personnel the challenges for armour designers are reported, and the importance of the relative size of the Hard Armour Plate to the Soft Armour Insert is strongly emphasised.

关键词： Body armour Body armor Ceramic armour Reaction sintered silicon carbide UHMWPE Fibres Fabrics Strike-face materials Aramids Small-arms ammunition

维普期刊数据库

Innovative Compensation Methods for Large Voltage Drop Effects in Very Long HVDC Transmission Systems

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and energy Systems 2021年第1期7卷 1-8页

作者： Mojtaba Mohaddes Ting An Jingjing Lu Narinder Dhaliwal Marcio Szechtman Bjarne R.Andersen TransGrid solutions.Winnipeg Canada Global energy Interconnection Research Institute SGCC.Beijing 102209China Electrobras Rio de JaneiroBrazil Anderson Power Electronic solutions Ltd Bexhill on SeaUK

This paper discusses the impacts of large voltage drops on very long HVDC transmission lines,especially when operating in a monopolar *** effect of using dedicated metallic return(DMR)conductors is *** main focus is on the potential rise at the neutral point of the converters and the need for an increased range for the converter transformer tap *** grounding schemes for multiterminals transnational HVDC systems are presented:single point low impedance grounding and high impedance multi-point *** advantages of the high impedance scheme are *** innovative compensation method for voltage drop effects using a series HVDC converter is presented along with simulation *** novel series converter can address both issues of neutral voltage rise and the impractical tap changer *** put the ideas into the perspective,a realistic example of a transnational HVDC connecting China,central Asia,Russia and West Europe is presented.

关键词： DC grid grounding HVDC series compensation transnational HVDC

Review and Outlook of HVDC Grids as Backbone of Transmission System

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

CSEE Journal of Power and energy Systems 2021年第4期7卷 797-810页

作者： Mian Wang Ting An Hakan Ergun Yuanliang Lan Bjarne Andersen Marcio Szechtman Willem Leterme Jef Beerten Dirk Van Hertem KU Leuven/energy Ville Belgium Global energy Interconnection Research Institute SGCCBeijing 102209China Andersen Power Electronic solutions Ltd Bexhill on SeaUnited Kingdom Eletrobras Brazil

HVDC technology has undergone many major developments in the past decades,resulting in higher power ratings,increased efficiency,and the availability of effective means for HVDC grid *** developments have made overlay HVDC grids a viable option to shift towards a carbon-free power system,by enabling optimal use of renewable *** particular,overlay HVDC grids greatly increase the prospect of building(trans-)continental supergrids to facilitate global economic ***,overlay HVDC grids still encounter challenges due to the distance and amount of power *** paper focuses on analyzing the readiness of the current technologies and the challenges associated with overlay HVDC *** in-depth analysis is carried out to evaluate the applicability of current technologies for overlay HVDC *** on the review of recent research and development efforts,the gaps and challenges towards the realization of a global HVDC grid are summarized.

关键词： Global energy interconnection(GEI) overlay HVDC grid renewable energy supergrid