检索结果-内蒙古大学图书馆

Cobalt phosphosulfide nanoparticles encapsulated into heteroatom-doped carbon as bifunctional electrocatalyst for Znair battery

学校读者我要写书评

暂无评论

Advanced Powder Materials

Advanced Powder Materials 2022年第3期1卷 46-53页

作者： Xiaolong Xu Shuo Wang Shiquan Guo Kwan San Hui Jiameng Ma Duc Anh Dinh Kwun Nam Hui Hao Wang Lipeng Zhang Guowei Zhou School of Materials Science and Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China Engineering Faculty of ScienceUniversity of East AngliaNorwichUnited Kingdom Joint Key Laboratory of the Ministry of Education Institute of Applied Physics and Materials EngineeringUniversity of MacaoAvenida da UniversidadeTaipaMacao SARChina NTT Hi-tech Institute Nguyen Tat Thanh UniversityHo Chi Minh City 700000Viet Nam College of Energy State Key Laboratory of Organic Inorganic CompositesBeijing University of Chemical TechnologyBeijing 100029China Key Laboratory of Fine Chemicals in Universities of Shandong Jinan Engineering Laboratory for Multi-scale Functional MaterialsSchool of Chemistry and Chemical EngineeringQilu University of Technology(Shandong Academy of Sciences)Jinan 250353China

CoPS nanoparticles encapsulated with S,P,N tri-doped carbon material(SPNC)were proposed as bifunctional electrocatalyst of oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)derived from zeolitic imidazolate *** functional theory calculations consistently revealed that P element in CoPS@SPNC improves the electrical conductivity and reduces OH^(*)hydrogenation energy barrier on Co sites,thereby facilitating the overall ORR/OER activities.A flexible Zn–air battery with CoPS@SPNC delivered an overpotential of 0.49 V,an energy efficiency above 80%,and a discharge voltage of 1.29 V at 2 mA cm^(-2) for 80 h.

关键词： Bifunctional electrocatalyst Zeolitic imidazolate framework Heteroatom doping Zn-air battery

Effect of Secondary Austenite on the Mechanical Properties of Uns S32750 Duplex Stainless Steel

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Wu, Xiao-Han Song, Zhigang He, Jian-Guo Feng, Han Wang, Bao-Shun Wu, Ming-Hua School of Material Science and Engineering University of Science and Technology Beijing Beijing100083 China Special Steel Institute Central Iron & Steel Research Institute Beijing100081 China Zhejiang Jiuli Hi-Tech Metals Co. Ltd. Zhejiang Huzhou313028 China Yongxing Special Stainless-Steel Co. Ltd. Zhejiang Huzhou313005 China

In this research, the effect of the secondary austenite (γ2) on mechanical properties was investigated by using optical microscope, scanning electron microscope, energy dispersive spectroscopy, electron backscattered diffraction and transmission electron microscope. The consequence was evaluated by impact and tensile tests. Secondary austenite had concentration on N and varied the alloying elements in austenite, which led to the reduction of the stacking faults energy (SFE). A positive effect on tensile strength was found due to the effect of N solution strengthening. The occurrence of high dense dislocation walls and α'-martensite, facilitated by the reduction of the SFE, appeared to be one of the main reasons to enhance the strength and decrease the elongation and toughness. The needle-liked or fine-grained morphologies of secondary austenite damaged the directionality of the lamellar-shaped two phases, making the weaker hindrance to impact cracks and a worse combination of plastic and ductile in austenite and ferrite, which contributed to the decrease in impact toughness and the elongation. © 2022, The Authors. All rights reserved.

关键词： Fracture toughness

Heat Transfer Investigation and Optimization of a Cooling Channel with Pin-Fins and Recessed-Extruded Endwalls

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Do, Khanh-Duy Cong Chung, Duy-Hung Plourde, Frédéric Kim, Kwang-Yong Pham, Gia-Diem Dinh, Cong-Truong Department of Aerospace Engineering School of Mechanical Engineering Hanoi University of Science and Technology No. 1 Dai Co Viet Road Hai Ba Trung District Hanoi11615 Viet Nam Viettel Aerospace Institute Viettel Building–Hoa Lac Hi-Tech Park Hanoi100000 Viet Nam ENSMA INSTITUT P’ UPR3346 1 avenue Clément Ader BP 40109 Futuroscope Chasseneuil86961 Cedex France Department of Mechanical Engineering Inha University 100 Inha-Ro Nam-Gu Incheon22212 Korea Republic of

This paper involves implementing and optimizing a novel recessed-extruded endwall design for a rectangular cooling channel equipped with pin-fins. The study encompasses an in-depth exploration of the flow dynamics, pondering the generation and sustenance of vortices within the channel, using Reynolds-averaged Navier-Stokes analysis. The study delves into the evaluation of heat transfer characteristics, considering crucial parameters such as Nusselt number, friction factor, and overall heat transfer performance. These attributes are contrasted against the corresponding values observed in cases featuring flat endwalls, concerning Reynolds numbers spanning from 7400 to 36000. A parametric study of the channel with recessedextruded endwalls is conducted, aiming to comprehend the influence of geometric factors on channel heat transfer. A singleobjective optimization process focusing on enhancing heat transfer efficacy, quantified through the heat transfer efficiency index (HTEI), is conducted with three design variables. Through the design optimization using the radial basis neural network (RBNN) surrogate model and particle swarm optimization (PSO) technique, the HTEI of the recessed-extruded endwall design shows enhancements of 91.7% and 18.0% compared with the flat endwall and reference designs, respectively, at a Reynolds number of 21500. The present work demonstrates potential for enhancing the heat transfer of pin-fins channels by improving endwall design. © 2023, The Authors. All rights reserved.

关键词： Nusselt number

Bifunctional Oxygen Electrocatalysts Enriched with Single Fe Atoms and Nife2o4 Nanoparticles for Rechargeable Zinc–Air Batteries

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Hu, Hao Meng, Yu Mei, Yi Hou, Peng-Xiang Liu, Chang Cheng, Hui-Ming Shao, Minhua Li, Jin-Cheng Faculty of Chemical Engineering Yunnan Provincial Key Laboratory of Energy Saving in Phosphorus Chemical Engineering and New Phosphorus Materials Kunming University of Science and Technology Kunming650500 China Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang110016 China Department of Chemical and Biological Engineering Energy Institute Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong HKUST-Shenzhen Research Institute No. 9 Yuexing 1st RD South Area Hi-tech Park Nanshan Shenzhen518057 China Fok Ying Tung Research Institute Hong Kong University of Science and Technology Guangzhou511458 China

Rechargeable zinc–air batteries (ZABs) have stimulated extensive interests, but the slow reaction kinetics of oxygen reactions hinder their further development. Here a bifunctional oxygen electrocatalyst enriched with both single Fe atoms and NiFe2O4 nanoparticles is designed to mitigate this issue. Specifically, iron phthalocyanine with single–atom Fe–N4 moiety is coupled with graphene by p-p stacking interaction to accelerate the oxygen reduction reaction (ORR) during discharging, while NiFe–based Prussian blue analogue derived NiFe2O4 nanoparticles are anchored on graphene to promote the oxygen evolution reaction (OER) during charging. The catalyst shows a small overpotential difference of 0.72 V between OER potential at 10 mA cm–2 and ORR half–wave potential. When used as an oxygen electrode catalyst, the corresponding ZAB exhibits a large power density of 185 mW cm–2, a small charge–discharge voltage gap of 0.717 V at 5 mA cm–2, and outstanding discharge–charge durability without any decay after 1035 cycles. This work offers a new concept to design multifunctional catalysts and stimulates the development of ZABs. © 2022, The Authors. All rights reserved.

关键词： Graphene

Numerical Investigation of Heat Transfer Characteristics of Pin-Fins with Roughed Endwalls in Gas Turbine Blade Internal Cooling Channels

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Do, Khanh-Duy Cong Chung, Duy-Hung Tran, Dang-Quoc Dinh, Cong-Truong Nguyen, Quang-Hai Kim, Kwang-Yong School of Mechanical Engineering Hanoi University of Science and Technology No. 1 Dai Co Viet Road Hai Ba Trung District Hanoi10000 Viet Nam Viettel Aerospace Institute Viettel Building – Hoa Lac Hi-Tech Parrk Hanoi100000 Viet Nam Department of Mechanical Engineering Inha University 100 Inha-Ro Nam-Gu Incheon22212 Korea Republic of

In modern jet engines, the effective cooling structure design is essential to both increase turbine efficiency and in the meantime, maintain structural integrality. Pin-fin arrays play an important role in the cooling mechanism of the turbine blade internal cooling system. Within the context of investigating the efficiency of cooling techniques using pin-fins, while the other studies focus on the pin-fin configurations, the current study is a step forward towards the optimization of cooling cascade endwalls for the better maneuver and reservation of vortices which lead to higher heat transfer near the endwalls. This study presents the results from the investigations of the flow-field and heat transfer characteristics of the pin-fin arrays with roughed endwalls, i.e., recessed endwalls and extruded endwalls types. The heat transfer and pressure drop characteristics of the channel are numerically examined to compare with those of the flat endwalls case within a range of inlet Reynolds number, which varies from 7400 to 36000. Both the leading and trailing sides of the channel are divided into five regions in the streamwise direction to further understand the heat transfer capacity of the pin-fins and the endwalls. The results show that, with these new endwall configurations, the high heat transfer regions near the pin-fins are remarkably enlarged compared to the flat endwalls. And, in the meantime, both the new endwall configurations enhance the heat transfer capacity of the channel near the pin-fins. The two new designs outperform the baseline case with the Nusselt number enhanced by 37.8% for the recessed endwalls and 15.9% for the extruded endwalls. By varying the height of the indentation and the protrusion, it is found that, with smaller height, both configurations produce a much lower friction factor but with much higher heat transfer capacity, leading to relatively higher values of heat transfer efficiency index (HTEI), up to 77.7% and 41.5% of the recessed and

关键词： Turbomachine blades

Enhancing strength at elevated temperatures via dynamic high-density mobile dislocations in Mg alloys

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2025年

作者： Fan, Mingyu Cui, Ye Zhou, Xin Chen, Junming Zhang, Yang Sun, Lixin Brechtl, Jamieson Fang, Daqing Li, Qian Ding, Qingqing Bei, Hongbin Liaw, Peter K. Xue, Yanzhuo Wang, Xun-Li Lu, Yang Zhang, Zhongwu Key Laboratory of Superlight Materials and Surface Technology Ministry of Education College of Materials Science and Chemical Engineering Harbin Engineering University Harbin150001 China Department of Physics and Center for Neutron Scattering City University of Hong Kong Kowloon Hong Kong999077 China Shenzhen Research Institute of City University of Hong Kong Shenzhen Hi-Tech Industrial Park Shenzhen518057 China Department of Mechanical Engineering City University of Hong Kong Kowloon China Physikalisches Institut Westfälische Wilhelms-Universität Münster48149 Germany Department of Materials Science and Engineering The University of Tennessee KnoxvilleTN37996-2100 United States State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and Engineering Xi'an Jiaotong University Xi'an710049 China National Engineering Research Center for Magnesium Alloy Chongqing University Chongqing400044 China State Key Laboratory of Advanced Special Steels & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering Shanghai University Shanghai200444 China School of Materials Science and Engineering Zhejiang University Hangzhou310027 China College of Shipbuilding Engineering Harbin Engineering University Harbin150001 China Department of Mechanical Engineering The University of Hong Kong Hong Kong999077 China

Dislocation strengthening, as one of the methods to simultaneously enhance the room temperature strength and ductility of alloys, does not achieve the desired strengthening and plasticity effect during elevated-temperature deformation. Here, we report a novel strategy to boost the dislocation multiplication and accumulation during deformation at elevated temperatures through dynamic strain aging (DSA). With the introduction of the rare-earth element Ho in Mg-Y-Zn alloy, Ho atoms diffuse toward dislocations during deformation at elevated temperatures, provoking the DSA effect, which increases the dislocation density significantly via the interactions of mobile dislocations and Ho atoms. The resulting alloy achieves a great enhancement of dislocation hardening and obtains the dual benefits of high strength and good ductility simultaneously at high homologous temperatures. The present work provides an effective strategy to enhancing the strength and ductility for elevated-temperature materials. © 2025

关键词： Ductility

Investigation on the metallurgical and welding characteristics of AA7075/Fly ash composites

学校读者我要写书评

暂无评论

Materials Today: Proceedings 2024年

作者： S. Prakasam K. Kannakumar D. Mohanraj M. Karthi S. Sakthi S. Nanthakumar Department of Mechanical Engineering Shree Venkateshwara Hi-Tech Engineering College Erode 638 455 Tamilnadu India Department of Mechanical Engineering University College of Engineering Anna University Thirukkuvalai 610 204 Tamilnadu India Department of Mechanical Engineering PSG Institute of Technology and Applied Research Coimbatore 641 062 Tamilnadu India

This study reinforces aluminium alloy AA7075 with industrial byproduct fly ash (FA) to improve the material's metallurgical and tribological qualities. Variable amounts of fly ash were included into a high-temperature vacuum stir casting process to create metal matrix composites (viz. 0, 6, and 12 wt%). From 60 BHN (AA7075) to 80 BHN (for 12 wt% FA), the hardness of the reinforced Al alloy was pointedly increased. Although there was only a little shift in values from 263 to 251 J for impact strength, this was in direct contrast to the upward trend shown in hardness. Different process factors, including FA concentration, sliding velocity, and applied load, were examined to see how the composites worn against an EN31 hardened steel disc. Extreme abrasive grooves and brittle fracture were observed at low levels of FA (between 0 and 6 wt%), whereas mild abrasive tracked by crumbling of the protective tribo-layer was observed at higher levels of fly ash (12 wt%). Taguchi design of trials was used to find the sweet spot between the several process parameters that would result in the least amount of sliding wear. Sliding at 1 m/s with an applied load of 20 N yielded the lowest wear rate for a composite with 12 % fly ash reinforcement.

关键词： Aluminium Fly ash Optimization Wear rate Hardness Impact strength

An efficient procedure of multi-frequency use for image reconstruction in ultrasound tomography 4th

学校读者我要写书评

暂无评论

An efficient procedure of multi-frequency use for image reco...

4th International Conference on Research in Intelligent and Computing in engineering, RICE 2019

作者： Huy, Tran Quang Nguyen, Van Dung Dung, Chu Thi Phuong Ninh, Bui Trung Tan, Tran Duc Faculty of Physics Hanoi Pedagogical University 2 XuanhoaVinhphuc Viet Nam NTT Hi-Tech Institute Nguyen Tat Thanh University Ho Chi Minh City Viet Nam Faculty of Electronics & Telecommunications VNU University of Engineering & Technology Hanoi Viet Nam

ISBN: (纸本)9789811527791

Distorted Born iterative method (DBIM) using multi-frequency information has been studied and applied in ultrasound tomography. However, the use of different frequencies in different iterations in the DBIM method is not used consistently. The value of the frequency hopping step is often chosen depending on the simulation builder or experimenter. Based on the multi-frequency combination technique, this paper suggests an effective multi-frequency combination procedure to improve the quality of reconstructing ultrasound images using fundamental tone and overtones (FTaOT). The numerical simulation results show that the normalized error of the suggested scheme is decreased by 45% in comparison with the dual-frequency method. Other multi-frequency combination scenarios are also simulated to demonstrate the feasibility of the proposed method. © Springer Nature Singapore Pte Ltd. 2020.

关键词： Image reconstruction

Characterization and evaluation of Ca/Al LDHS adsorbents synthesized by a one-step hydrothermal method for congo red removal 2nd

学校读者我要写书评

暂无评论

Characterization and evaluation of Ca/Al LDHS adsorbents syn...

2nd International Conference on Metal Material Processes and Manufacturing, ICMMPM 2019

作者： Thi, Hong Tham Nguyen Uyen, Dao Thi To Nguyen, Duy Chinh Tran, Van Thuan Lam, Tri Duc Bach, Long Giang N-Vo, Dai Viet Nguyen, Dai Hai Do, Sy Trung Nguyen, Trinh Duy NTT Hi-Tech Institute Nguyen Tat Thanh University Ho Chi Minh City Viet Nam Faculty of Chemical Engineering and Food Technology Nguyen Tat Thanh University Ho Chi Minh City Viet Nam Faculty of Chemical and Natural Resources Engineering Universiti Malaysia Pahang Malaysia Institute of Applied Materials Science Vietnam Academy of Science and Technology Ho Chi Minh City Viet Nam Institute of Chemistry Vietnam Academy of Science and Technology Hanoi City Viet Nam

ISBN: (纸本)9783035716320

We investigated the fabrication of Ca/Al layered double hydroxide (LDHs) via a one-step hydrothermal approach with slow hydrolysis of urea at a low temperature without further annealing required. The as-synthesized Ca/Al LDHs nanostructures obtained were defined using Fourier transforms infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results demonstrated that Ca/Al LDHs exhibit excellent adsorption performance on Congo red anionic dyes in aqueous solution. The adsorption capacity of the Ca/Al LDHs toward Congo red was found to be 59.41 mg/g. © 2020 Trans tech Publications Ltd, Switzerland.

关键词： Adsorption