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Tensile properties

QI Dongming, SHAO Jianzhong, WU Minghua, NITTA Kohhei

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 396-401 doi: 10.1007/s11705-008-0077-1

摘要: A novel phenolic rigid organic filler (KT) was used to modify isotactic polypropylene (iPP). The influence of KT particles on the tensile properties of PP/KT microcomposites was studied by uniaxial tensile test and the morphological structures of the stretched specimens were observed by scanning electron microscopy (SEM) and polarized optical microscopy (POM). We found that the Young’s modulus of PP/KT specimens increased with filler content, while the yield and break of the specimens are related to the filler particles size. The yield stress, the breaking stress and the ultimate elongation of PP/KT specimens were close to those of unfilled iPP specimens when the maximal filler particles size is less than a critical value, which is 7 ?m at a crosshead speed of 10 mm/min and 3 ?m at 200 mm/min, close to that of glass bead but far more than those of other rigid inorganic filler particles. The interfacial interaction was further estimated from yield stress, indicating that KT particles have a moderate interfacial interaction with iPP matrix. Thus, the incorporation of small KT particles can reinforce iPP matrix and simultaneously cause few detrimental effects on the other excellent tensile properties of iPP matrix, due to their organic nature, higher specific area, solid true-spherical shape and the homogenous dispersion of the ROF particles in microcomposites.

关键词: maximal     uniaxial tensile     unfilled     excellent tensile     influence    

Efficient acetylene/carbon dioxide separation with excellent dynamic capacity and low regeneration energy

《化学科学与工程前沿(英文)》   页码 1616-1622 doi: 10.1007/s11705-022-2183-x

摘要: Adsorptive separation of acetylene/carbon dioxide mixtures by porous materials is an important and challenging task due to their similar sizes and physical properties. Here, remarkable acetylene/carbon dioxide separation featuring a high dynamic breakthrough capacity for acetylene (4.3 mmol·g–1) as well as an ultralow acetylene regeneration energy (29.5 kJ·mol–1) was achieved with the novel TiF62–-pillared material ZU-100 (TIFSIX-bpy-Ni). Construction of a pore structure with abundant TiF62– anion sites and pores with appropriate sizes enabled formation of acetylene clusters through hydrogen bonds and intermolecular interactions, which afforded a high acetylene capacity (8.3 mmol·g–1) and high acetylene/carbon dioxide uptake ratio (1.9) at 298 K and 1 bar. Moreover, the NbO52– anion-pillared material ZU-61 investigated for separation of acetylene/carbon dioxide. In addition, breakthrough experiments were also conducted to further confirm the excellent dynamic acetylene/carbon dioxide separation performance of ZU-100.

关键词: adsorption     acetylene/carbon dioxide separation     dynamic capacity     anion-pillared hybrid material    

Acoustic emissions evaluation of the dynamic splitting tensile properties of steel fiber reinforced concrete

《结构与土木工程前沿(英文)》   页码 1341-1356 doi: 10.1007/s11709-023-0988-4

摘要: This study empirically investigated the influence of freeze–thaw cycling on the dynamic splitting tensile properties of steel fiber reinforced concrete (SFRC). Brazilian disc splitting tests were conducted using four loading rates (0.002, 0.02, 0.2, and 2 mm/s) on specimens with four steel fiber contents (0%, 0.6%, 1.2%, and 1.8%) subjected to 0 and 50 freeze–thaw cycles. The dynamic splitting tensile damage characteristics were evaluated using acoustic emission (AE) parameter analysis and Fourier transform spectral analysis. The results quantified using the freeze–thaw damage factor defined in this paper indicate that the degree of damage to SFRC caused by freeze–thaw cycling was aggravated with increasing loading rate but mitigated by increasing fiber content. The percentage of low-frequency AE signals produced by the SFRC specimens during loading decreased with increasing loading rate, whereas that of high-frequency AE signals increased. Freeze–thaw action had little effect on the crack types observed during the early and middle stages of the loading process; however, the primary crack type observed during the later stage of loading changed from shear to tensile after the SFRC specimens were subjected to freeze–thaw cycling. Notably, the results of this study indicate that the freeze–thaw damage to SFRC reduces AE signal activity at low frequencies.

关键词: steel fiber reinforced concrete     freeze–thaw cycling     Brazilian disc splitting test     acoustic emission technique     dynamic splitting tensile acoustic emission properties    

An artificial neural network model on tensile behavior of hybrid steel-PVA fiber reinforced concrete

Fangyu LIU, Wenqi DING, Yafei QIAO, Linbing WANG

《结构与土木工程前沿(英文)》 2020年 第14卷 第6期   页码 1299-1315 doi: 10.1007/s11709-020-0712-6

摘要: The tensile behavior of hybrid fiber reinforced concrete (HFRC) is important to the design of HFRC and HFRC structure. This study used an artificial neural network (ANN) model to describe the tensile behavior of HFRC. This ANN model can describe well the tensile stress-strain curve of HFRC with the consideration of 23 features of HFRC. In the model, three methods to process output features (no-processed, mid-processed, and processed) are discussed and the mid-processed method is recommended to achieve a better reproduction of the experimental data. This means the strain should be normalized while the stress doesn’t need normalization. To prepare the database of the model, both many direct tensile test results and the relevant literature data are collected. Moreover, a traditional equation-based model is also established and compared with the ANN model. The results show that the ANN model has a better prediction than the equation-based model in terms of the tensile stress-strain curve, tensile strength, and strain corresponding to tensile strength of HFRC. Finally, the sensitivity analysis of the ANN model is also performed to analyze the contribution of each input feature to the tensile strength and strain corresponding to tensile strength. The mechanical properties of plain concrete make the main contribution to the tensile strength and strain corresponding to tensile strength, while steel fibers tend to make more contributions to these two items than PVA fibers.

关键词: artificial neural network     hybrid fiber reinforced concrete     tensile behavior     sensitivity analysis     stress-strain curve    

Characterization of the tensile properties of friction stir welded aluminum alloy joints based on axial

Biranchi PANDA,A. GARG,Zhang JIAN,Akbar HEIDARZADEH,Liang GAO

《机械工程前沿(英文)》 2016年 第11卷 第3期   页码 289-298 doi: 10.1007/s11465-016-0393-y

摘要:

Friction stir welding (FSW) process has gained attention in recent years because of its advantages over the conventional fusion welding process. These advantages include the absence of heat formation in the affected zone and the absence of large distortion, porosity, oxidation, and cracking. Experimental investigations are necessary to understand the physical behavior that causes the high tensile strength of welded joints of different metals and alloys. Existing literature indicates that tensile properties exhibit strong dependence on the rotational speed, traverse speed, and axial force of the tool that was used. Therefore, this study introduces the experimental procedure for measuring tensile properties, namely, ultimate tensile strength (UTS) and tensile elongation of the welded AA 7020 Al alloy. Experimental findings suggest that a welded part with high UTS can be achieved at a lower heat input compared with the high heat input condition. A numerical approach based on genetic programming is employed to produce the functional relationships between tensile properties and the three inputs (rotational speed, traverse speed, and axial force) of the FSW process. The formulated models were validated based on the experimental data, using the statistical metrics. The effect of the three inputs on the tensile properties was investigated using 2D and 3D analyses. A high UTS was achieved, including a rotational speed of 1050 r/min and traverse speed of 95 mm/min. The results also indicate that 8 kN axial force should be set prior to the FSW process.

关键词: tensile properties     ultimate tensile strength     tensile elongation     friction stir welding     tool rotational speed     genetic programming     welding speed    

multifunctional polypyrrole/cellulose nanofiber composite films with outstanding photothermal effect, excellent

《化学科学与工程前沿(英文)》 2023年 第17卷 第8期   页码 1028-1037 doi: 10.1007/s11705-022-2251-2

摘要: Electrodes that combine energy storage with mechanical and photothermal performance are necessary for efficient development and use of flexible energy storage and conversion devices. In this study, the flexible, ultrathin, and multifunctional polypyrrole/cellulose nanofiber composite films were fabricated via a one-step “soak and polymerization” method. The dense sandwich structure and strong interfacial interaction endowed polypyrrole/cellulose nanofiber composite films with excellent flexibility, outstanding mechanical strength, and desired toughness. Interestingly, the polypyrrole/cellulose nanofiber composite film electrodes with quaternary amine functionalized cellulose nanofiber had the highest specific mass capacitance (392.90 F∙g–1) and specific areal capacitance (3.32 F∙cm–2) than the electrodes with unmodified and carboxyl functionalized cellulose nanofibers. Further, the polypyrrole/cellulose nanofiber composite films with sandwich structure had excellent photothermal conversion properties. This study demonstrated a feasible and versatile method for preparing of multifunctional composite films, having promising applications in various energy storage fields.

关键词: cellulose nanofiber     electrochemical     photothermal conversion     polypyrrole    

Biaxial tensile-compressive experiment of concrete at high temperatures

SONG Yupu, ZHANG Zhong, QING Likun, YU Changjiang

《结构与土木工程前沿(英文)》 2007年 第1卷 第1期   页码 94-98 doi: 10.1007/s11709-007-0009-z

摘要: Biaxial tension-compression experiments of concrete of five stress ratios at high temperatures were carried out using the large static-dynamic triaxial test system in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology. The stress ratios s1/s3 are 0, 0.1, 0.25, 0.50, and 0.75. The temperatures are 20vH, 200vH, 300vH, 500vH, 600vH. The mechanical behavior of concrete under biaxial tension-compression at high temperatures is analyzed. It is found that both the tensile strength and strain diminished with the increase in temperature under each stress ratio. Based on the test results, the relationship between tensile strengths and stress ratios and temperature is proposed. In addition, the failure criterion of concrete under biaxial stress state of tension-compression at high temperatures is established.

关键词: increase     Offshore Engineering     temperature     relationship     addition    

Strategic position and development prospects of nuclear energy in China

SHEN Wenquan

《能源前沿(英文)》 2007年 第1卷 第2期   页码 125-128 doi: 10.1007/s11708-007-0015-9

摘要: By analyzing the challenges of China s energy supply, an excellent perspective of nuclear power development in the country has been described. Taking into account the near-, mid-, and long-term development requirements, a comprehensive, coordinated and sustainable nuclear power program is proposed. Thus, our national nuclear industry can not only catch up with the world s advanced level in proper time, but also possess enough stamina for sustainability.

关键词: development     excellent perspective     long-term development     comprehensive     national    

Co anchored on porphyrinic triazine-based frameworks with excellent biocompatibility for conversion of

《化学科学与工程前沿(英文)》 2022年 第16卷 第12期   页码 1761-1771 doi: 10.1007/s11705-022-2195-6

摘要: Microbial electrosynthesis is a promising alternative to directly convert CO2 into long-chain compounds by coupling inorganic electrocatalysis with biosynthetic systems. However, problems arose that the conventional electrocatalysts for hydrogen evolution may produce extensive by-products of reactive oxygen species and cause severe metal leaching, both of which induce strong toxicity toward microorganisms. Moreover, poor stability of electrocatalysts cannot be qualified for long-term operation. These problems may result in poor biocompatibility between electrocatalysts and microorganisms. To solve the bottleneck problem, Co anchored on porphyrinic triazine-based frameworks was synthesized as the electrocatalyst for hydrogen evolution and further coupled with Cupriavidus necator H16. It showed high selectivity for a four-electron pathway of oxygen reduction reaction and low production of reactive oxygen species, owing to the synergistic effect of Co–Nx modulating the charge distribution and adsorption energy of intermediates. Additionally, low metal leaching and excellent stability were observed, which may be attributed to low content of Co and the stabilizing effect of metalloporphyrins. Hence, the electrocatalyst exhibited excellent biocompatibility. Finally, the microbial electrosynthesis system equipped with the electrocatalyst successfully converted CO2 to poly-β-hydroxybutyrate. This work drew up a novel strategy for enhancing the biocompatibility of electrocatalysts in microbial electrosynthesis system.

关键词: microbial electrosynthesis     hydrogen evolution reaction     metalloporphyrins     biocompatibility     CO2 conversion    

Tensile ratcheting behaviors of bronze powder filled polytetrafluoroethylene

Wenjuan XU, Hong GAO, LiLan GAO, Xu CHEN, Yong WANG

《化学科学与工程前沿(英文)》 2013年 第7卷 第1期   页码 103-109 doi: 10.1007/s11705-013-1315-8

摘要: A series of tensile and ratcheting experiments for compacted polytetrafluoroethylene (PTFE) and bronze filled PTFE (PTFE/bronze) were conducted on dynamic mechanical analyzer (DMA-Q800). The effects of mean stress, stress amplitude and temperature on the ratcheting behaviors of PTFE and PTFE/bronze were investigated. It is found that the stress-strain response of PTFE/bronze is nonlinear and its elastic modulus is higher than that of pure PTFE. For uniaxial ratcheting test, the dissipation strain energy density (DSED) decreases rapidly in the first 10 cycles and approaches a constant after 20 cycles. The ratcheting strain and the DSED corresponding to 100 cycles increase with increasing mean stress, stress amplitude and temperature. Additionally, the DSED and ratcheting strain of PTFE/bronze are much lower than those of pure PTFE under the same experimental conditions. It is also found that both pure PTFE and PTFE/bronze present cyclic hardening characteristics. Above all, the addition of bronze can improve both the uniaxial tensile property and the cyclic property of PTFE.

关键词: bronze filled polytetrafluoroethylene (PTFE/bronze)     uniaxial tensile behavior     ratcheting behavior     dissipation strain energy density (DSED)    

Multiscale mechanical modeling of hydrated cement paste under tensile load using the combined DEM-MD

Yue HOU, Linbing WANG

《结构与土木工程前沿(英文)》 2017年 第11卷 第3期   页码 270-278 doi: 10.1007/s11709-017-0408-8

摘要: In this paper, a combined DEM-MD method is proposed to simulate the crack failure process of Hydrated Cement Paste (HCP) under a tensile force. A three-dimensional (3D) multiscale mechanical model is established using the combined Discrete Element Method (DEM)-Molecular Dynamics (MD) method in LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator). In the 3D model, HCP consists of discrete particles and atoms. Simulation results show that the combined DEM-MD model is computationally efficient with good accuracy in predicting tensile failures of HCP.

关键词: hydrated cement paste     multiscale     MD simulation     DEM    

Aerobic granulation of pure bacterial strain

ADAV Sunil S., LEE Duu-Jong

《环境科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 461-467 doi: 10.1007/s11783-008-0066-0

摘要: The objective of this study is to cultivate aerobic granules by pure bacterial strain, , in a sequencing batch reactor. Stable granules sized 2.0–2.2 mm were formed in the reactor after a five-week cultivation. These granules exhibited excellent settling attributes, and degraded phenol at rates of 1.49 and 1.19 g phenol/(g VSS·d) at 250 and 1500 mg/L of phenol concentration, respectively. Confocal laser scanning microscopic test results show that was distributed over the initial small aggregates, and the outer edge of the granule was away from the core regime in the following stage.

关键词: following     excellent settling     phenol/     sequencing     microscopic    

Ni particles with phosphorus and adjacent defects catalyze 1,5-dinitronaphthalene hydrogenation with excellent

Wei Xiong, Susu Zhou, Zeyong Zhao, Fang Hao, Zhihui Cai, Pingle Liu, Hailiang Zhang, Hean Luo

《化学科学与工程前沿(英文)》 2021年 第15卷 第4期   页码 998-1007 doi: 10.1007/s11705-020-1994-x

摘要: This work proposes a modified activated carbon support, with defects and heteroatoms (N,P-ACs) by nitrogen and phosphorus doping to load non-noble nickel to catalyze aromatic compound hydrogenation. The Ni/N,P-ACs-900 (prepared at 900 °C) showed promising catalytic activity in liquid-phase 1,5-dinitronaphthalene hydrogenation with a 1,5-diaminonaphthalene yield of 95.8% under the mild condition of 100 °C, which is comparable to the commercial Pd/C catalyst. The nitrogen species were burned off at 900 °C, causing more defects for nickel metal loading, facilitating the interaction between the supports and the nickel metal, and resulting in highly dispersed metal particles. The computational study of the nickel binding energy has been conducted using density functional theory. It exhibits that the defects formed by heteroatom doping are beneficial to nickel anchoring and deposition to form highly uniform nickel particles. The phosphorus species in combination with the defects are suitable for H adsorption and dissociation. These results reveal that the heteroatomic doping on the active carbon shows significant effects in the hydrogenation of the liquid-phase aromatic compounds. These findings could provide a promising route for the rational design of aromatic compound hydrogenation catalysts to significantly decrease the cost by instead using noble metal catalysts in the industry.

关键词: nitrogen and phosphorus doping     non-noble nickel catalyst     aromatic compounds hydrogenation    

Graphene-like -BN supported polyhedral NiS/NiS nanocrystals with excellent photocatalytic performance

《化学科学与工程前沿(英文)》 2021年 第15卷 第6期   页码 1537-1549 doi: 10.1007/s11705-021-2094-2

摘要: Human health is deteriorating due to the effluent containing heavy metal ions and organic dyes. Hence, photoreduction of Cr(VI) to Cr(III) and degradation of rhodamine B (RhB) using a novel photocatalyst is particularly important. In this work, h-BN/NiS2/NiS composites were prepared via a simple solvothermal method and a double Z-scheme heterojunction was constructed for efficiently removing RhB and Cr(VI). The 7 wt-% h-BN/NiS2/NiS composites were characterized via a larger specific surface area (15.12 m2·g–1), stronger light absorption capacity, excellent chemical stability, and high yield of electrons and holes. The experimental result indicated that the photoreduction efficiency of the 7 wt-% h-BN/NiS2/NiS photocatalyst achieved 98.5% for Cr(VI) after 120 min, which was about 3 times higher than that of NiS2/NiS (34%). However, the removal rate of RhB by the 7 wt-% h-BN/NiS2/NiS photocatalyst reached 80%. This is due to the double Z-scheme heterojunction formed between NiS2/NiS and h-BN, which improved the charge separation efficiency and transmission efficiency. Besides, the influence of diverse photogenerated electron and hole scavengers upon the photoreduction of Cr(VI) was studied, the results indicated that graphene-like h-BN promoted transportation of photoinduced charges on the surface of the h-BN/NiS2/NiS photocatalyst via the interfacial effects.

关键词: graphene-like h-BN     h-BN/NiS2/NiS composites     photocatalysis     Cr(VI) reduction     degradation of RhB    

Time- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 1025-1037 doi: 10.1007/s11709-021-0741-9

摘要: The understanding of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill (FR-CPB) play crucial roles in the successful implementation of reinforcement technique in underground mine backfilling operations. However, very limited studies have been performed to gain insight into the evolution of compressive and tensile behaviors and associated mechanical properties of FR-CPB under various curing temperatures from early to advanced ages. Thus, this study aims to investigate the time (7, 28, and 90 d)- and temperature (20°C, 35°C, and 45°C)-dependence of constitutive behavior and mechanical properties of FR-CPB. The obtained results show that pre- and post-failure behaviors of FR-CPB demonstrate strongly curing temperature-dependence from early to advanced ages. Moreover, the pseudo-hardening behavior is sensitive to curing temperature, especially at early ages. Furthermore, the mechanical properties including elastic modulus, material stiffness, strengths, brittleness, cohesion, and internal friction angle of FR-CPB show increasing trends with curing temperature as curing time elapses. Additionally, a predictive model is developed to capture the strong correlation between compressive and tensile strength of FR-CPB. The findings of this study will contribute to the successful implementation of FR-CPB technology.

关键词: cemented paste backfill     fiber reinforcement     constitutive behavior     temperature     tailings    

标题 作者 时间 类型 操作

Tensile properties

QI Dongming, SHAO Jianzhong, WU Minghua, NITTA Kohhei

期刊论文

Efficient acetylene/carbon dioxide separation with excellent dynamic capacity and low regeneration energy

期刊论文

Acoustic emissions evaluation of the dynamic splitting tensile properties of steel fiber reinforced concrete

期刊论文

An artificial neural network model on tensile behavior of hybrid steel-PVA fiber reinforced concrete

Fangyu LIU, Wenqi DING, Yafei QIAO, Linbing WANG

期刊论文

Characterization of the tensile properties of friction stir welded aluminum alloy joints based on axial

Biranchi PANDA,A. GARG,Zhang JIAN,Akbar HEIDARZADEH,Liang GAO

期刊论文

multifunctional polypyrrole/cellulose nanofiber composite films with outstanding photothermal effect, excellent

期刊论文

Biaxial tensile-compressive experiment of concrete at high temperatures

SONG Yupu, ZHANG Zhong, QING Likun, YU Changjiang

期刊论文

Strategic position and development prospects of nuclear energy in China

SHEN Wenquan

期刊论文

Co anchored on porphyrinic triazine-based frameworks with excellent biocompatibility for conversion of

期刊论文

Tensile ratcheting behaviors of bronze powder filled polytetrafluoroethylene

Wenjuan XU, Hong GAO, LiLan GAO, Xu CHEN, Yong WANG

期刊论文

Multiscale mechanical modeling of hydrated cement paste under tensile load using the combined DEM-MD

Yue HOU, Linbing WANG

期刊论文

Aerobic granulation of pure bacterial strain

ADAV Sunil S., LEE Duu-Jong

期刊论文

Ni particles with phosphorus and adjacent defects catalyze 1,5-dinitronaphthalene hydrogenation with excellent

Wei Xiong, Susu Zhou, Zeyong Zhao, Fang Hao, Zhihui Cai, Pingle Liu, Hailiang Zhang, Hean Luo

期刊论文

Graphene-like -BN supported polyhedral NiS/NiS nanocrystals with excellent photocatalytic performance

期刊论文

Time- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced

期刊论文