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Multiscale model of micro curing residual stress evolution in carbon fiber-reinforced thermoset polymer

Xinyu HUI, Yingjie XU, Weihong ZHANG

《机械工程前沿(英文)》 2020年 第15卷 第3期   页码 475-483 doi: 10.1007/s11465-020-0590-6

摘要: In this study, the micro curing residual stresses of carbon fiber-reinforced thermoset polymer (CFRP) composites are evaluated using a multiscale modeling method. A thermochemical coupling model is developed at the macroscale level to obtain the distributions of temperature and degree of cure. Meanwhile, a representative volume element model of the composites is established at the microscale level. By introducing the information from the macroscale perspective, the curing residual stresses are calculated using the microscale model. The evolution of curing residual stresses reveals the interaction mechanism of fiber, matrix, and interphase period during the curing process. Results show that the curing residual stresses mostly present a tensile state in the matrix and a compressive state in the fiber. Furthermore, the curing residual stresses at different locations in the composites are calculated and discussed. Simulation results provide an important guideline for the analysis and design of CFRP composite structures.

关键词: CFRP     curing residual stress     multiscale modeling     finite element method    

A modified pulse charging method for lithium-ion batteries by considering stress evolution, charging

Yanfei ZHAO, Bo LU, Yicheng SONG, Junqian ZHANG

《结构与土木工程前沿(英文)》 2019年 第13卷 第2期   页码 294-302 doi: 10.1007/s11709-018-0460-z

摘要: The stress evolution, total charging time and capacity utilization of pulse charging (PC) method are investigated in this paper. It is found that compared to the conventional constant current (CC) charging method, the PC method can accelerate the charging process but will inevitably cause an increase in stress and a decrease in capacity. The charging speed for PC method can be estimated by the mean current. By introducing stress control, a modified PC method called the PCCC method, which starts with a PC operation followed by a CC operation, is proposed. The PCCC method not only can accelerate charging process but also can avoid the stress raising and capacity loss occurring in the PC method. Furthermore, the optimal pulsed current density and switch time in the PCCC method is also discussed.

关键词: fast charging method     pulse charging     stress evolution     charging time     capacity utilization    

非均质岩体中一维应力波演化过程分析

钟光复,王志亮,李永池

《中国工程科学》 2006年 第8卷 第5期   页码 58-62

摘要:

地下球形药包爆轰后将产生很强的地震波,其传播受到多种因素的影响。把岩石介质的弹塑性帽盖模型耦合到有限差分法程序中,对一维爆轰波在非均质岩石体中的传播、演化机理进行了数值模拟与分析;着重探讨了一维应力波从“硬”岩石层进入“软”岩石层、从“软”岩石层进入“硬”岩石层时,波在形状和强度等方面的变化规律;同时探讨了岩石介质中存在的“软弱夹层”对一维应力波传播的影响。

关键词: 岩石介质     一维应力波     帽盖模型     传播与演化    

Tuned reactive power dispatch through modified differential evolution technique

S. BISWAS (RAHA), N. CHAKRABORTY

《能源前沿(英文)》 2012年 第6卷 第2期   页码 138-147 doi: 10.1007/s11708-012-0188-8

摘要: This paper explores the capability of modified differential evolution (MDE) technique for solving the reactive power dispatch (RPD) problem. The proposed method is based on the basic differential evolution (DE) technique with a few modifications made into it. DE is one of the strongest optimization techniques though it suffers from the problem of slow convergence while global minima appear. The proposed modifications are tried to resolve the problem. The RPD problem mainly defines loss minimization with stable voltage profile. To solve the RPD problem, the generator bus voltage, transformer tap setting and shunt capacitor placements are controlled by the MDE approach. In this paper, IEEE 14-bus and IEEE 30-bus systems are chosen for MDE implementation. The applied modification show much improved result in comparison to normal DE technique. Comparative study with other soft-computing technique including DE validates the effectiveness of the proposed method.

关键词: reactive power dispatch (RPD)     modified differential evolution (MDE)     differential evolution algorithm with localizations around the best vector (DELB)    

Strategic Thinking on a Revolution/an Evolution in Production and Consumption of Energy in China

Ke-chang Xie,Ke Liu

《工程管理前沿(英文)》 2014年 第1卷 第1期   页码 30-36 doi: 10.15302/J-FEM-2014006

摘要: This article summarizes the thinking behind the call for a revolution/an evolution in China's energy production and consumption. China is still a developing country, though it has experienced fast economic growth in the past thirty years. It achieved great accomplishments surprising the world, and it is also confronted with challenges on energy supply and environmental protection. As environmental pollution becomes more and more serious, the energy challenges have become more and more complicated. With this in mind, the authors analyzed China's energy situation, China's energy supply and consumption, the world energy map, China's commitment both to improving its domestic environment and fulfilling its international obligations to control climate change. Action plans are presented to support the call for a revolution/an evolution in China's energy production and consumption as an effective assurance for China's ambitious goal of building a moderately prosperous society in all respects.

关键词: revolution     evolution     energy     production     consumption    

Polypyrrole@NiCo hybrid nanotube arrays as high performance electrocatalyst for hydrogen evolution reaction

Shenghua Ye, Gaoren Li

《化学科学与工程前沿(英文)》 2018年 第12卷 第3期   页码 473-480 doi: 10.1007/s11705-018-1724-9

摘要:

The polypyrrole(PPy)@NiCo hybrid nanotube arrays have been successfully fabricated as a high performance electrocatalyst for hydrogen evolution reaction (HER) in alkaline solution. The strong electronic interactions between PPy and NiCo alloy are confirmed by X-ray photoelectron spectroscopy and Raman spectra. Because these interations can remarkably reduce the apparent activation energy (Ea) for HER and enhance the turnover frequency of catalysts, the electrocatalytic performance of PPy@NiCo hybrid nanotube arrays are significantly improved. The electrochemical tests show that the PPy@NiCo hybrid catalysts exhibit a low overpotential of ~186 mV at 10.0 mA·cm2 and a small tafel slope of 88.6 mV·deg1 for HER in the alkaline solution. The PPy@NiCo hybrid nanotubes also exhibit high catalytic activity and high stability for HER.

关键词: NiCo alloy     polypyrrole     hybrid nanotube     electrocatalyst     hydrogen evolution reaction    

Synergistic effect of V and Fe in Ni/Fe/V ternary layered double hydroxides for efficient and durable oxygen evolution

《化学科学与工程前沿(英文)》 2023年 第17卷 第1期   页码 102-115 doi: 10.1007/s11705-022-2179-6

摘要: High-performance and stable electrocatalysts are vital for the oxygen evolution reaction (OER). Herein, via a one-pot hydrothermal method, Ni/Fe/V ternary layered double hydroxides (NiFeV-LDH) derived from Ni foam are fabricated to work as highly active and durable electrocatalysts for OER. By changing the feeding ratio of Fe and V salts, the prepared ternary hydroxides were optimized. At an Fe:V ratio of 0.5:0.5, NiFeV-LDH exhibits outstanding OER activity superior to that of the binary hydroxides, requiring overpotentials of 269 and 274 mV at 50 mA·cm–2 in the linear sweep voltammetry and sampled current voltammetry measurements, respectively. Importantly, NiFeV-LDH shows extraordinary long-term stability (≥ 75 h) at an extremely high current density of 200 mA·cm–2. In contrast, the binary hydroxides present quick decay at 200 mA·cm–2 or even reduced current densities (150 and 100 mA·cm–2). The outstanding OER performance of NiFeV-LDH benefits from the synergistic effect of V and Fe while doping the third metal into bimetallic hydroxide layers: (a) Fe plays a crucial role as the active site; (b) electron-withdrawing V stabilizes the high valence state of Fe, thus accelerating the OER process; (c) V further offers great stabilization for the formed intermediate of FeOOH, thus achieving superior durability.

关键词: oxygen evolution reaction     electrocatalysts     ternary layered double hydroxides     long-term stability    

heterostructure grown on nickel foam as efficient and durable self-supported electrocatalysts for hydrogen evolution

《化学科学与工程前沿(英文)》 2023年 第17卷 第4期   页码 437-448 doi: 10.1007/s11705-022-2228-1

摘要: High-performance and ultra-durable electrocatalysts are vital for hydrogen evolution reaction (HER) during water splitting. Herein, by one-pot solvothermal method, MoOx/Ni3S2 spheres comprising Ni3S2 nanoparticles inside and oxygen-deficient amorphous MoOx outside in situ grow on Ni foam (NF), to assembly the heterostructure composites of MoOx/Ni3S2/NF. By adjusting volume ratio of the solvents of ethanol to water, the optimized MoOx/Ni3S2/NF-11 exhibits the best HER performance, requiring an extremely low overpotential of 76 mV to achieve the current density of 10 mA∙cm‒2 (η10 = 76 mV) and an ultra-small Tafel slope of 46 mV∙dec‒1 in 0.5 mol∙L‒1 H2SO4. More importantly, the catalyst shows prominent high catalytic stability for HER (> 100 h). The acid-resistant MoOx wraps the inside Ni3S2/NF to ensure the high stability of the catalyst under acidic conditions. Density functional theory calculations confirm that the existing oxygen vacancy and MoOx/Ni3S2 heterostructure are both beneficial to the reduced Gibbs free energy of hydrogen adsorption (|∆GH*|) over Mo sites, which act as main active sites. The heterostructure effectively decreases the formation energy of O vacancy, leading to surface reconstruction of the catalyst, further improving HER performance. The MoOx/Ni3S2/NF is promising to serve as a highly effective and durable electrocatalyst toward HER.

关键词: molybdenum oxides     oxygen vacancies     heterostructure     electrocatalysts     hydrogen evolution reaction    

Innovation evolution of China’s high-speed rail industry

Jin CHEN, Liang MEI

《工程管理前沿(英文)》 2018年 第5卷 第4期   页码 548-552 doi: 10.15302/J-FEM-2018208

摘要:

The International Conference on the Evolution of China Urban Water Environment & Ecology, 2019

Jiuhui Qu

《环境科学与工程前沿(英文)》 2019年 第13卷 第6期 doi: 10.1007/s11783-019-1179-3

High-entropy catalysts for electrochemical water-electrolysis of hydrogen evolution and oxygen evolution

《能源前沿(英文)》 doi: 10.1007/s11708-023-0892-6

摘要: High entropy materials (HEMs) have developed rapidly in the field of electrocatalytic water-electrolysis for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) due to their unique properties. In particular, HEM catalysts are composed of many elements. Therefore, they have rich active sites and enhanced entropy stability relative to single atoms. In this paper, the preparation strategies and applications of HEM catalysts in electrochemical water-electrolysis are reviewed to explore the stabilization of HEMs and their catalytic mechanisms as well as their application in support green hydrogen production. First, the concept and four characteristics of HEMs are introduced based on entropy and composition. Then, synthetic strategies of HEM catalysts are systematically reviewed in terms of the categories of bottom-up and top-down. The application of HEMs as catalysts for electrochemical water-electrolysis in recent years is emphatically discussed, and the mechanisms of improving the performance of electrocatalysis is expounded by combining theoretical calculation technology and ex-situ/in situ characterization experiments. Finally, the application prospect of HEMs is proposed to conquer the challenges in HEM catalyst fabrications and applications.

关键词: high-entropy     electrocatalysis     synthetic methods     water-electrolysis     hydrogen and oxygen evolutions    

Interspecies transmission and evolution of the emerging coronaviruses: perspectives from bat physiology

Baicheng HUANG, Kegong TIAN

《农业科学与工程前沿(英文)》 2020年 第7卷 第2期   页码 218-226 doi: 10.15302/J-FASE-2020324

摘要:

Emergent coronaviruses (CoVs) such as SARS-CoV and MERS-CoV have posed great threats to public health worldwide over the past two decades. Currently, the emergence of SARS-CoV-2 as a pandemic causes greater public health concern. CoV diversity is due to the large size and replication mechanisms of the genomes together with having bats as their optimum natural hosts. The ecological behavior and unique immune characteristics of bats are optimal for the homologous recombination of CoVs. The relationship of spatial structural characteristics of the spike protein, a protein that is critical for recognition by host receptors, in different CoVs may provide evidence in explaining the coevolution of CoVs and their hosts. This information may help to enhance our understanding of CoV evolution and thus provide part of the basis of preparations for any future outbreaks.

关键词: bat     coronavirus     evolution     host receptor     spike protein     transmission    

Organizational evolution of project management teams over the whole lifecycle of megaprojects: Case study

《工程管理前沿(英文)》   页码 439-454 doi: 10.1007/s42524-022-0211-7

摘要: Project management teams are critical in the implementation of megaprojects, but their evolution throughout the project lifecycle has not been clearly explained. This paper explores the organizational evolution of megaproject management teams through a longitudinal retrospective case study of the Hong Kong–Zhuhai–Macao Bridge (HZMB) project. The organizational evolution is examined in terms of management objectives, management content, and organizational structure. The organizational evolution of the HZMB project management team exhibits stage differentiation with the coexistence of turbulence and stability. Changes in the external environment are the driving force for organizational evolution, whereas a flexible organizational strategy is critical in promoting this evolution. Basing on the HZMB case study, this paper summarizes six critical measures that facilitate the organizational evolution of megaproject management teams. Our findings add value to megaproject management theory and provide a better understanding of the dynamics and complexity of megaproject organizational management.

关键词: megaproject     organizational evolution     whole lifecycle management     project management team    

butt: heteroatomic porous carbon nanosheets with edge-induced topological defects for enhanced oxygen evolution

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1755-1764 doi: 10.1007/s11705-023-2318-8

摘要: Owing to the complexity of electron transfer pathways, the sluggish oxygen evolution reaction process is defined as the bottleneck for the practical application of Zn–air batteries. In this effort, metal nanoparticles (Co, Ni, Fe, etc.) encapsulated within nitrogen-doped carbon materials with abundant edge sites were synthesized by one-step pyrolysis treatment using cigarette butts as raw materials, which can drastically accelerate the overall rate of oxygen evolution reaction by facilitating the adsorption of oxygenated intermediates by the edge-induced topological defects. The prepared catalyst of nitrogen-doped carbon porous nanosheets loaded with Co nanoparticles (Co@NC-500) exhibits enhanced catalytic activity toward oxygen evolution reaction, with a low overpotential of 350 mV at the current density of 10 mA·cm–2. Furthermore, the Zn–air battery assembled with Co@NC-500 catalyst demonstrates a desirable performance affording an open-circuit potential of 1.336 V and power density of 33.6 mW·cm–2, indicating considerable practical application potential.

关键词: oxygen evolution reaction     porous carbon nanosheets     Co nanoparticles     edge-induced topological defects     Zn–air batteries    

EFFECTS OF TRANSPORT STRESS ON THE INTESTINES INVOLVING NEURONAL NITRIC OXIDE SYNTHASE

《农业科学与工程前沿(英文)》   页码 285-295 doi: 10.15302/J-FASE-2022469

摘要:

● Transport stress declined the level of leukocytes including lymphocytes in rat serum.

关键词: intestine     nNOS     nNOS-positive neurons     transport stress    

标题 作者 时间 类型 操作

Multiscale model of micro curing residual stress evolution in carbon fiber-reinforced thermoset polymer

Xinyu HUI, Yingjie XU, Weihong ZHANG

期刊论文

A modified pulse charging method for lithium-ion batteries by considering stress evolution, charging

Yanfei ZHAO, Bo LU, Yicheng SONG, Junqian ZHANG

期刊论文

非均质岩体中一维应力波演化过程分析

钟光复,王志亮,李永池

期刊论文

Tuned reactive power dispatch through modified differential evolution technique

S. BISWAS (RAHA), N. CHAKRABORTY

期刊论文

Strategic Thinking on a Revolution/an Evolution in Production and Consumption of Energy in China

Ke-chang Xie,Ke Liu

期刊论文

Polypyrrole@NiCo hybrid nanotube arrays as high performance electrocatalyst for hydrogen evolution reaction

Shenghua Ye, Gaoren Li

期刊论文

Synergistic effect of V and Fe in Ni/Fe/V ternary layered double hydroxides for efficient and durable oxygen evolution

期刊论文

heterostructure grown on nickel foam as efficient and durable self-supported electrocatalysts for hydrogen evolution

期刊论文

Innovation evolution of China’s high-speed rail industry

Jin CHEN, Liang MEI

期刊论文

The International Conference on the Evolution of China Urban Water Environment & Ecology, 2019

Jiuhui Qu

期刊论文

High-entropy catalysts for electrochemical water-electrolysis of hydrogen evolution and oxygen evolution

期刊论文

Interspecies transmission and evolution of the emerging coronaviruses: perspectives from bat physiology

Baicheng HUANG, Kegong TIAN

期刊论文

Organizational evolution of project management teams over the whole lifecycle of megaprojects: Case study

期刊论文

butt: heteroatomic porous carbon nanosheets with edge-induced topological defects for enhanced oxygen evolution

期刊论文

EFFECTS OF TRANSPORT STRESS ON THE INTESTINES INVOLVING NEURONAL NITRIC OXIDE SYNTHASE

期刊论文