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TiO supported IrO for anode reversal tolerance in proton exchange membrane fuel cell

《能源前沿(英文)》 2022年 第16卷 第5期   页码 852-861 doi: 10.1007/s11708-021-0811-7

摘要: Fuel starvation can occur and cause damage to the cell when proton exchange membrane fuel cells operate under complex working conditions. In this case, carbon corrosion occurs. Oxygen evolution reaction (OER) catalysts can alleviate carbon corrosion by introducing water electrolysis at a lower potential at the anode in fuel shortage. The mixture of hydrogen oxidation reaction (HOR) and unsupported OER catalyst not only reduces the electrolysis efficiency, but also influences the initial performance of the fuel cell. Herein, Ti4O7 supported IrOx is synthesized by utilizing the surfactant-assistant method and serves as reversal tolerant components in the anode. When the cell reverse time is less than 100 min, the cell voltage of the MEA added with IrOx/Ti4O7 has almost no attenuation. Besides, the MEA has a longer reversal time (530 min) than IrOx (75 min), showing an excellent reversal tolerance. The results of electron microscopy spectroscopy show that IrOx particles have a good dispersity on the surface of Ti4O7 and IrOx/Ti4O7 particles are uniformly dispersed on the anode catalytic layer. After the stability test, the Ti4O7 support has little decay, demonstrating a high electrochemical stability. IrOx/Ti4O7 with a high dispersity has a great potential to the application on the reversal tolerance anode of the fuel cell.

关键词: proton exchange membrane fuel cell (PEMFC)     fuel starvation     cell reverse     reversal tolerance anode     oxygen evolution reaction    

Time reversal method for guided wave inspection in pipes

DENG Fei, WU Bin, HE Cunfu

《机械工程前沿(英文)》 2008年 第3卷 第3期   页码 251-260 doi: 10.1007/s11465-008-0050-1

摘要: The application of the time reversal method in pipe-like structures based on finite element method (FEM) is investigated. A steel pipe model measuring 70 mm × 3.5 mm is used to analyze the reflection coefficient of the (0,2) mode with the time reversal process. Simulation results show that the time reversal array method is beneficial to the improvement of the signal-to-noise ratio of a guided wave inspection system. As the intercepting window is widened, more energy is included in re-emitted signals, which leads to a large reflection coefficient of the (0,2) mode. In parallel, a circumferential locating method based on the time reversal method is described. The time reversal process used for guided wave inspection leads to the temporal and spatial focusing. When the time reversal signals are re-emitted, the angular profile obtained at the axial location of the defect can be used to determine the circumferential location of the defect. Except for a pipe with one defect, the circumferential locating method has been verified on another pipe model with two defects. Meanwhile, the elements number of the time reversal array has been discussed for enhancing the discrimination of the defect circumferential location.

关键词: reversal process     beneficial     circumferential location     energy     number    

碳基燃料SOFC阳极材料研究进展

孙春文,孙杰,杨伟,马朝晖,李 帅,仙存妮, 王少飞,肖睿娟,施思齐,李 泓,陈立泉

《中国工程科学》 2013年 第15卷 第2期   页码 77-87

摘要:

固体氧化物燃料电池(SOFCs)是一类可以将燃料气体的化学能以高效而环境友好的方式直接转化为电能的电化学反应器。最近的研究趋势是发展可以直接电化学氧化碳氢化合物燃料(如天然气)的电池,但是使用碳氢化合物作为燃料时,目前最常使用的镍-氧化钇稳定的氧化锆(Ni/YSZ)金属陶瓷阳极材料具有易积碳和硫中毒的缺点。因此,研究在燃料气氛下具有混合离子-电子电导的替代阳极材料显得尤为必要。综述了以碳基燃料工作的SOFCs阳极材料研究的一些进展,并展望本领域在未来的发展趋势。

关键词: 固体氧化物燃料电池     阳极材料     碳基燃料     抗积碳     抗硫    

Flow, thermal, and vibration analysis using three dimensional finite element analysis for a flux reversal

B. VIDHYA,K. N. SRINIVAS

《能源前沿(英文)》 2016年 第10卷 第4期   页码 424-440 doi: 10.1007/s11708-016-0423-9

摘要: This paper presents the simulation of major mechanical properties of a flux reversal generator (FRG) viz., computational fluid dynamic (CFD), thermal, and vibration. A three-dimensional finite element analysis (FEA) based CFD technique for finding the spread of pressure and air velocity in air regions of the FRG is described. The results of CFD are mainly obtained to fine tune the thermal analysis. Thus, in this focus, a flow analysis assisted thermal analysis is presented to predict the steady state temperature distribution inside FRG. The heat transfer coefficient of all the heat producing inner walls of the machine are evaluated from CFD analysis, which forms the main factor for the prediction of accurate heat distribution. The vibration analysis is illustrated. Major vibration sources such as mechanical, magnetic and applied loads are covered elaborately which consists of a 3D modal analysis to find the natural frequency of FRG, a 3D static stress analysis to predict the deformation of the stator, rotor and shaft for different speeds, and an unbalanced rotor harmonic analysis to find eccentricity of rotor to make sure that the vibration of the rotor is within the acceptable limits. Harmonic analysis such as sine sweep analysis to identify the range of speeds causing high vibrations and steady state vibration at a mode frequency of 1500 Hz is presented. The vibration analysis investigates the vibration of the FRG as a whole, which forms the contribution of this paper in the FRG literature.

关键词: flux reversal generator     air velocity     computation fluid dynamics     thermal analysis     vibration analysis     finite element analysis    

Functional tolerance theory in incremental growth design

YANG Bo, ZE Xiangbo, YANG Tao

《机械工程前沿(英文)》 2007年 第2卷 第3期   页码 336-343 doi: 10.1007/s11465-007-0059-x

摘要: The evolutionary tolerance design strategy and its characteristics are studied on the basis of automation technology in the product structure design. To guarantee a successful transformation from the functional requirement to geometry constraints between parts, and finally to dimension constraints, a functional tolerance design theory in the process of product growth design is put forward. A mathematical model with a correlated sensitivity function between cost and the tolerance is created, in which the design cost, the manufacturing cost, the usage cost, and the depreciation cost of the product are regarded as control constraints of the tolerance allocation. Considering these costs, a multifactor-cost function to express quality loss of the product is applied into the model. In the mathematical model, the minimum cost is used as the objective function; a reasonable process capability index, the assembly function, and assembly quality are taken as the constraints; and depreciation cost in the objective function is expressed as the discount rate terminology in economics. Thus, allocation of the dimension tolerance as the function and cost over the whole lifetime of the product is realized. Finally, a design example is used to demonstrate the successful application of the proposed functional tolerance theory in the incremental growth design of the product.

关键词: successful transformation     mathematical     automation technology     tolerance allocation     minimum    

Three-dimensional composite Li metal anode by simple mechanical modification for high-energy batteries

《能源前沿(英文)》 2023年 第17卷 第5期   页码 569-584 doi: 10.1007/s11708-023-0875-7

摘要: Lithium (Li) metal is believed to be the “Holy Grail” among all anode materials for next-generation Li-based batteries due to its high theoretical specific capacity (3860 mAh/g) and lowest redox potential (−3.04 V). Disappointingly, uncontrolled dendrite formation and “hostless” deposition impede its further development. It is well accepted that the construction of three-dimensional (3D) composite Li metal anode could tackle the above problems to some extent by reducing local current density and maintaining electrode volume during cycling. However, most strategies to build 3D composite Li metal anode require either electrodeposition or melt-infusion process. In spite of their effectiveness, these procedures bring multiple complex processing steps, high temperature, and harsh experimental conditions which cannot meet the actual production demand in consideration of cost and safety. Under this condition, a novel method to construct 3D composite anode via simple mechanical modification has been recently proposed which does not involve harsh conditions, fussy procedures, or fancy equipment. In this mini review, a systematic and in-depth investigation of this mechanical deformation technique to build 3D composite Li metal anode is provided. First, by summarizing a number of recent studies, different mechanical modification approaches are classified clearly according to their specific procedures. Then, the effect of each individual mechanical modification approach and its working mechanisms is reviewed. Afterwards, the merits and limits of different approaches are compared. Finally, a general summary and perspective on construction strategies for next-generation 3D composite Li anode are presented.

关键词: lithium (Li)-ion battery (LIB)     Li metal battery     three-dimensional (3D) composite Li metal anode     mechanical modification     reducing local current density    

The effects of festivals and special events on city image design

LIU Yuan, CHEN Chong

《结构与土木工程前沿(英文)》 2007年 第1卷 第2期   页码 255-259 doi: 10.1007/s11709-007-0032-0

摘要: City marketing provides a good vehicle to strengthen a city in competition. On the analysis of the important roles of events and city image in the context of city marketing, this paper suggests that holding festivals or special events is an effective approach to enhance city marketing. The positive impacts of festivals and special events, such as the identification of city image, the promotion of the transmission of city image, and the reversal of the negative image of the city, are discussed. The negative impacts of festivals and special events are also talked about. The unique image of the city could be identified by the City Mind Identity, the City Visual Identity and the City Behavior Identity concerned with festivals and special events.

关键词: Visual Identity     reversal     transmission     marketing     Behavior Identity    

Algal biomass derived biochar anode for efficient extracellular electron uptake from

Yan-Shan Wang, Dao-Bo Li, Feng Zhang, Zhong-Hua Tong, Han-Qing Yu

《环境科学与工程前沿(英文)》 2018年 第12卷 第4期 doi: 10.1007/s11783-018-1072-5

摘要:

Algal biochar anode produced higher biocurrent compared with graphite plate anode.

Algal biochar exhibited stronger electrochemical response to redox mediators.

Algal biochar showed excellent adsorption to redox mediators.

关键词: Algal biochar     Anode material     Electrochemical activity     Extracellular electron transport     Waste resource utilization    

Preparation of biomass-derived carbon loaded with MnO as lithium-ion battery anode for improving its

《化学科学与工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11705-023-2376-y

摘要: Biomass-derived carbon materials for lithium-ion batteries emerge as one of the most promising anodes from sustainable perspective. However, improving the reversible capacity and cycling performance remains a long-standing challenge. By combining the benefits of K2CO3 activation and KMnO4 hydrothermal treatment, this work proposes a two-step activation method to load MnO2 charge transfer onto biomass-derived carbon (KAC@MnO2). Comprehensive analysis reveals that KAC@MnO2 has a micro-mesoporous coexistence structure and uniform surface distribution of MnO2, thus providing an improved electrochemical performance. Specifically, KAC@MnO2 exhibits an initial charge-discharge capacity of 847.3/1813.2 mAh·g–1 at 0.2 A·g–1, which is significantly higher than that of direct pyrolysis carbon and K2CO3 activated carbon, respectively. Furthermore, the KAC@MnO2 maintains a reversible capacity of 652.6 mAh·g–1 after 100 cycles. Even at a high current density of 1.0 A·g–1, KAC@MnO2 still exhibits excellent long-term cycling stability and maintains a stable reversible capacity of 306.7 mAh·g–1 after 500 cycles. Compared with reported biochar anode materials, the KAC@MnO2 prepared in this work shows superior reversible capacity and cycling performance. Additionally, the Li+ insertion and de-insertion mechanisms are verified by ex situ X-ray diffraction analysis during the charge-discharge process, helping us better understand the energy storage mechanism of KAC@MnO2.

关键词: biomass-derived carbon     MnO2     lithium-ion batteries     anode material     high reversible capacity    

APPLE SUMO E3 LIGASE MDSIZ1 NEGATIVELY REGULATES DROUGHT TOLERANCE

《农业科学与工程前沿(英文)》 2021年 第8卷 第2期

摘要:

Drought stress typically causes heavy losses in apple production and uncovering the mechanisms by which apple tolerates drought stress is important in apple breeding. MdSIZ1 is a SUMO (small ubiquitin-like modifier) E3 ligase that promotes SUMO binding to substrate proteins. Here, we demonstrate that MdSIZ1 in apple has a negative relationship with drought tolerance. MdSIZ1 RNAi transgenic apple trees had a higher survival rate after drought stress. During drought stress they had higher leaf water potential, reduced ion leakage, lower H2O2 and malondialdehyde contents, and higher catalase activity. In addition, MdSIZ1 RNAi transgenic plants had a higher net photosynthetic rate during the latter period of drought stress. Finally, the transgenic apple trees also altered expression levels of some microRNAs in response to drought stress. Taken together, these results indicate that apple MdSIZ1 negatively regulates drought stress by enhancing leaf water-holding capacity and antioxidant enzyme activity.

 

关键词: apple / drought tolerance / gene expression / MdSIZ1    

中国铝工业应用新型电极材料的研究与展望

邱竹贤

《中国工程科学》 2001年 第3卷 第5期   页码 50-54

摘要:

介绍了现代铝工业上新近开发研制的几种电极材料,涉及惰性阴极、惰性阳极、双极性电极等;还研制了低温电解质,使电解温度降低到800~900℃。如果惰性电极与低温电解质配合起来应用,则能够明显减少工业铝生产中的物料消耗,节省电能,增大电解槽生产能力,并改善环境状况,可望大幅度降低生产成本。

关键词: 惰性阳极     惰性阴极     SiC绝缘侧壁     低温铝电解    

A Robust Tolerance Design Method Based on Fuzzy Quality Loss

CAO Yan-long, MAO Jian, YANG Jiang-xin, WU Zhao-tong, WU Li-qun

《机械工程前沿(英文)》 2006年 第1卷 第1期   页码 101-105 doi: 10.1007/s11465-005-0010-y

摘要:

The traditional tolerance design model ignores the impact of noise factor, so that the design may be infeasible due to variations in design constraints. Based on the analysis of fuzzy factors in tolerance design and the limitations of the traditional Taguchi squared quality loss function, a fuzzy quality loss function model utilizing fuzzy theory was introduced. Concepts on fuzzy quality loss and fuzzy quality loss cost were proposed in the model. The characteristics of the new model and the advantages over the traditional Taguchi quality loss function were analyzed. A robust tolerance design model using a fuzzy quality loss function was proposed. An example was given to illustrate the proposed model. Results and comparisons show that the method is suitable and reliable, and makes the conclusions more objective and reasonable.

关键词: impact     function     robust tolerance     suitable     quality    

A logic-based controller for the mitigation of ventilation air methane in a catalytic flow reversal reactor

Zhikai LI, Zhangfeng QIN, Yagang ZHANG, Zhiwei WU, Hui WANG, Shuna LI, Mei DONG, Weibin FAN, Jianguo WANG

《化学科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 347-356 doi: 10.1007/s11705-013-1347-0

摘要: The control system of a catalytic flow reversal reactor (CFRR) for the mitigation of ventilation air methane was investigated. A one-dimensional heterogeneous model with a logic-based controller was applied to simulate the CFRR. The simulation results indicated that the controller developed in this work performs well under normal conditions. Air dilution and auxiliary methane injection are effective to avoid the catalyst overheating and reaction extinction caused by prolonged rich and lean feed conditions, respectively. In contrast, the reactor is prone to lose control by adjusting the switching time solely. Air dilution exhibits the effects of two contradictory aspects on the operation of CFRR, i.e., cooling the bed and accumulating heat, though the former is in general more prominent. Lowering the reference temperature for flow reversal can decrease the bed temperature and benefit stable operation under rich methane feed condition.

关键词: ventilation air methane     reverse flow reactor     lean methane combustion     logic-based controller     mathematical modeling    

Spectral reflectance indices as proxies for yield potential and heat stress tolerance in spring wheat

Caiyun LIU, Francisco PINTO, C. Mariano COSSANI, Sivakumar SUKUMARAN, Matthew P. REYNOLDS

《农业科学与工程前沿(英文)》 2019年 第6卷 第3期   页码 296-308 doi: 10.15302/J-FASE-2019269

摘要:

The application of spectral reflectance indices (SRIs) as proxies to screen for yield potential (YP) and heat stress (HS) is emerging in crop breeding programs. Thus, a comparison of SRIs and their associations with grain yield (GY) under YP and HS conditions is important. In this study, we assessed the usefulness of 27 SRIs for indirect selection for agronomic traits by evaluating an elite spring wheat association mapping initiative (WAMI) population comprising 287 elite lines under YP and HS conditions. Genetic and phenotypic analysis identified 11 and 9 SRIs in different developmental stages as efficient indirect selection indices for yield in YP and HS conditions, respectively. We identified enhanced vegetation index (EVI) as the common SRI associated with GY under YP at booting, heading and late heading stages, whereas photochemical reflectance index (PRI) and normalized difference vegetation index (NDVI) were the common SRIs under booting and heading stages in HS. Genome-wide association study (GWAS) using 18704 single nucleotide polymorphisms (SNPs) from Illumina iSelect 90K identified 280 and 43 marker-trait associations for efficient SRIs at different developmental stages under YP and HS, respectively. Common genomic regions for multiple SRIs were identified in 14 regions in 9 chromosomes: 1B (60–62 cM), 3A (15, 85–90, 101–105 cM), 3B (132–134 cM), 4A (47–51 cM), 4B (71–75 cM), 5A (43–49, 56–60, 89–93 cM), 5B (124–125 cM), 6A (80–85 cM), and 6B (57–59, 71 cM). Among them, SNPs in chromosome 5A (89–93 cM) and 6A (80–85 cM) were co-located for yield and yield related traits. Overall, this study highlights the utility of SRIs as proxies for GY under YP and HS. High heritability estimates and identification of marker-trait associations indicate that SRIs are useful tools for understanding the genetic basis of agronomic and physiological traits.

关键词: genome-wide association study (GWAS)     heat tolerance     spectral reflectance     spring wheat    

Polyamines and antioxidant defense system are associated with cold tolerance in centipedegrass

Jingjing CHEN, Junyang FANG, Zhenfei GUO, Shaoyun LU

《农业科学与工程前沿(英文)》 2018年 第5卷 第1期   页码 129-138 doi: 10.15302/J-FASE-2017197

摘要: Physiological responses to low temperature were analyzed in a chilling-tolerant centipedegrass ( ) accession, Shao Guan (SG), in comparison to the commercial cultivar, Common. Lower levels of ion leakage and higher chlorophyll (Chl) concentration were observed in SG than in Common during chilling stress. The maximum photochemical efficiency, the actual photosystem II (PSII) efficiency, photochemical quenching efficiency, and net photosynthetic rate were decreased during chilling stress in both genotypes, with higher levels of these parameters shown by SG than Common. In addition, higher activities of superoxide dismutase (SOD), catalase (CAT), ascorbate-peroxidase (APX) and glutathione reductase (GR), and higher concentrations of ascorbic acid (AsA) and glutathione (GSH) were observed in SG than in Common. Moreover, higher concentrations of putrescine (Put), spermidine (Spd), and spermine (Spm) were observed in SG than in Common. Correlation analysis indicated that SOD, CAT, APX and GR activities, and AsA and GSH concentrations showed high correlation to Put, while APX, GR, and AsA concentrations were correlated to Spd. Exogenous Put or Spd increased antioxidant enzyme activities and chilling tolerance. The results suggested that polyamine-regulated antioxidants are important for chilling tolerance in centipedegrass and protect plants against chilling induced oxidative damage.

关键词: antioxidants     centipedegrass     chilling     photosynthesis     polyamines    

标题 作者 时间 类型 操作

TiO supported IrO for anode reversal tolerance in proton exchange membrane fuel cell

期刊论文

Time reversal method for guided wave inspection in pipes

DENG Fei, WU Bin, HE Cunfu

期刊论文

碳基燃料SOFC阳极材料研究进展

孙春文,孙杰,杨伟,马朝晖,李 帅,仙存妮, 王少飞,肖睿娟,施思齐,李 泓,陈立泉

期刊论文

Flow, thermal, and vibration analysis using three dimensional finite element analysis for a flux reversal

B. VIDHYA,K. N. SRINIVAS

期刊论文

Functional tolerance theory in incremental growth design

YANG Bo, ZE Xiangbo, YANG Tao

期刊论文

Three-dimensional composite Li metal anode by simple mechanical modification for high-energy batteries

期刊论文

The effects of festivals and special events on city image design

LIU Yuan, CHEN Chong

期刊论文

Algal biomass derived biochar anode for efficient extracellular electron uptake from

Yan-Shan Wang, Dao-Bo Li, Feng Zhang, Zhong-Hua Tong, Han-Qing Yu

期刊论文

Preparation of biomass-derived carbon loaded with MnO as lithium-ion battery anode for improving its

期刊论文

APPLE SUMO E3 LIGASE MDSIZ1 NEGATIVELY REGULATES DROUGHT TOLERANCE

期刊论文

中国铝工业应用新型电极材料的研究与展望

邱竹贤

期刊论文

A Robust Tolerance Design Method Based on Fuzzy Quality Loss

CAO Yan-long, MAO Jian, YANG Jiang-xin, WU Zhao-tong, WU Li-qun

期刊论文

A logic-based controller for the mitigation of ventilation air methane in a catalytic flow reversal reactor

Zhikai LI, Zhangfeng QIN, Yagang ZHANG, Zhiwei WU, Hui WANG, Shuna LI, Mei DONG, Weibin FAN, Jianguo WANG

期刊论文

Spectral reflectance indices as proxies for yield potential and heat stress tolerance in spring wheat

Caiyun LIU, Francisco PINTO, C. Mariano COSSANI, Sivakumar SUKUMARAN, Matthew P. REYNOLDS

期刊论文

Polyamines and antioxidant defense system are associated with cold tolerance in centipedegrass

Jingjing CHEN, Junyang FANG, Zhenfei GUO, Shaoyun LU

期刊论文