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Predicting recrystallized grain size in friction stir processed 304L stainless steel

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Journal of Materials Science & Technology 2019年第4期35卷 491-498页

作者： M.P.Miles T.W.Nelson c.Gunter f.c.liu L.fourment T.Mathis Manufacturing Engineering Department Brigham Young University centre de Mise en forme des Materiaux Mines ParisTech

A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone(HAZ). friction stir processing(fSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304 L stainless steel. A numerical simulation of the fSP process in 304 L was developed to predict temperatures and recrystallized grain size in the stir zone. The model employed an Eulerian finite element approach,where flow stresses for a large range of strain rates and temperatures inherent in fSP were used as input. Temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. The predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. The maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%.

关键词： Stainless steel Numerical simulation friction stir welding Recrystallized grain size

A displacement-based back-analysis method for rock mass modulusand horizontal in situ stress in tunneling-Illustrated with a case study

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A displacement-based back-analysis method for rock mass modu...

Rational modulation of fluorophosphate cathode by anionic groups to reduce the polarization behavior for fast-charging sodium-ion batteries

中国科学院地质与地球物理研究所2006学术年会

作者： L.Q.Zhang~a,Z.Q.Yue~b,Z.f.Yang~a,J.X.Qi~b,f.c.liu~b (a Institute of Geology and Geophysics,chinese Academy of Sciences,P.O.Box 9825, Beijing 100029,PR china) (b Department of civil Engineering,The University of Hong Kong,Pokfulam Road,Hong Kong,PR china) (c Beijing Hydroelectric Investigation and Design Institute,Beijing,PR china)

This paper presents a displacement based back-analysis method for the determination of rock mass modulus(E) and the horizontal in situ stress(P) perpendicular to the axis line of the tunnel excavation in hard and intact rock *** rock mass is assumed to respond in an isotropic and linear elastic ***,the method is a best-fit solution of back-analysis by comparing the measured displacements near a tunnel face during excavation with those calculated using a three-dimensional finite element *** method can be applied efficiently and effectively by iterative algorithms such as direct search technique and damping least square *** particular,a three-dimensional finite element pattern technique(3-D fEPT) is used to compute the theoretical displacements for saving computation *** method is further illustrated with a case *** case study deals with a test adit at Zhanghewan Pumped Storage Power Station in Hebei Province,North *** is shown that the back-analyzed results of E and P are reliable and representative for the actual rock masses.

关键词： Back-analysis Displacements Modulus In situ stresses 3-D fEPT field tests

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Journal of Energy chemistry 2025年第1期100卷 509-521页

作者： Xinyuan Wang fan Zhang Xingyu Zhou Qian Wang changyu liu Yangyang liu Hui Wang Xiaojie liu Key Laboratory of Synthetic and Natural functional Molecule of the Ministry of Education College of Chemistry & Materials Science Northwest University

Na3V2（PO4）2O2f （VP） is recognized as a promising cathode material for sodium-ion batteries due to its stable structural framework and high specific *** functional theory （DfT） and finite element simulations show that incorporating SO42-into VP decreases its band gap,lowers the migration energy barrier,and ensures a uniform Na+concentration gradient and stress distribution during charge and discharge ***,the average Na+diffusion coefficient of Na3V2（PO4）1.95（SO4）0.05O2f（VPS-1） is roughly double that of VP,leading to enhanced rate capability (80 c,75.5 mAh g-1) and cycling stability (111.0 mAh g-1capacity after 1000 cycles at 10 c current density) for ***-1 exhibits outstanding fast-charging capabilities,achieving an 80%state of charge in just 8.1 *** assembled VPS-1//SbSn/NPc full cell demonstrated stable cycling over 200 cycles at a high 5 c current,maintaining an average coulombic efficiency of 95.35%.

关键词： Anionic group modulation Polarization behavior fast-charging Sodium-ion battery fluorophosphate cathode

Role of the Greenland Sea ice anomaly in the late-spring drought over Northwest china

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Atmospheric and Oceanic Science Letters 2025年第1期18卷 1-5页

作者： Yang liu Huopo chen Nansen-Zhu International Research centre Institute of Atmospheric Physics Chinese Academy of SciencesBeijingChina collaborative Innovation center on forecast and Evaluation of Meteorological Disasters Nanjing University for Information Science and TechnologyNanjingChina

Drought across Northwest china in late spring has exerted a vital effect on the local climate and agricultural production,and has been alleviated during the past *** study explored the influence of the preceding Arctic sea ice on the May drought in Northwest china caused by the precipitation *** analysis indicated that when the Greenland Sea ice concentration is abnormally high during february to April,the dry conditions in Northwest china tend to be *** increase of sea ice in the Greenland Sea can excite a meridional circulation,which causes sea surface temperature(SST)anomalies in the North Atlantic via the sea-air interaction,manifested as significant warm SST anomalies over the south of Greenland and the subtropical North Atlantic,but negative SST anomalies over the west of the *** abnormal SST pattern maintains to May and triggers a zonal wave train from the North Atlantic through Scandinavia and central Asia to Northwest china,leading to abnormal cyclones in Northwest ***,Northwest china experiences a more humid climate than usual.

关键词： Arctic sea ice Greenland Sea North Atlantic SST Drought Northwest china

Low-cost and fluoride-free synthesis of MfI zeolite nanosheets with enhanced stability for benzene alkylation with ethanol

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Journal of Energy chemistry 2025年第1期100卷 458-468页

作者： Peng Zhu cun liu Yiren Yu Guoshu Gao Yumeng Zhao Xiongfu Zhang Guodong liu Guohui Yang State Key Laboratory of fine chemicals School of Chemical Engineering Dalian University of Technology State Key Laboratory of catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences

Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MfI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented *** obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MfI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.

关键词： MfI zeolite ZSM-5 Nanosheets Scale-up synthesis Aromatic alkylation

Engineering atomic Rb-N configurations to tune radical pathways for highly selective photocatalytic H2O2 synthesis coupled with biomass valorization

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Journal of Energy chemistry 2025年第1期100卷 215-225页

作者： Jiaye Li Shuang Pan Yihuang chen Qiong liu college of chemistry and Materials Engineering Wenzhou University Guangdong Provincial Key Laboratory of chemical Measurement and Emergency Test Technology (china) Institute of Analysis Guangdong Academy of Sciences (China National Analytical CenterGuangzhou)

Photocatalytic oxygen reduction for hydrogen peroxide （H2O2） synthesis presents a green and costeffective production ***,achieving highly selective H2O2synthesis remains challenging,necessitating precise control over free radical reaction pathways and minimizing undesirable oxidative ***,we report for the visible light-driven simultaneous co-photocatalytic reduction of O2to H2O2and oxidation of biomass using the atomic rubidium-nitride modified carbon nitride（cNRb）.The optimized cNRb catalyst demonstrates a record photoreduction rate of 8.01 mM h-1for H2O2generation and photooxidation rate of 3.75 mM h-1for furfuryl alcohol to furoic acid,achieving a remarkable solar-to-chemical conversion （Scc） efficiency of up to 2.27%.Experimental characterizations and DfT calculation disclosed that the introducing atomic Rb–N configurations allows for the high-selective generation of superoxide radicals while suppressing hydroxyl free radical *** is because the Rb–N serves as the new alternative site to perceive a stronger connection position for O2adsorption and reinforce the capability to extract protons,thereby triggering a high selective redox product *** study holds great potential in precisely regulating reactive radical processes at the atomic level,thereby paving the way for efficient synthesis of H2O2coupled with biomass valorization.

关键词： Atomic economy Radical pathway regulation Rubidium atom coordination Biomass valorization

Interconnections between diabetic corneal neuropathy and diabetic retinopathy:diagnostic and therapeutic implications

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Neural Regeneration Research 2025年第8期20卷 2169-2180页

作者： Mingyi Yu faith Teo En Ning chang liu Yu-chi liu Tissue Engineering and Stem cell Group Singapore Eye Research InstituteSingapore Yong Loo Lin School of Medicine National University of SingaporeSingapore Department of cornea and External Eye Disease Singapore National Eye CenterSingapore Ophthalmology and Visual Sciences Academic clinical Program Duke-NUS Medical SchoolSingapore

Diabetic corneal neuropathy and diabetic retinopathy are ocular complications occurring in the context of diabetes *** corneal neuropathy refers to the progressive damage of corneal *** retinopathy has traditionally been considered as damage to the retinal ***,growing evidence suggests that diabetic retinopathy is a complex neurovascular disorder resulting from dysfunction of the neurovascular unit,which includes both the retinal vascular structures and neural *** retinopathy is one of the leading causes of blindness and is frequently screened for as part of diabetic ocular ***,diabetic corneal neuropathy is commonly overlooked and underdiagnosed,leading to severe ocular surface *** studies have found that these two conditions tend to occur together,and they share similarities in their pathogenesis pathways,being triggered by a status of chronic *** review aims to discuss the interconnection between diabetic corneal neuropathy and diabetic retinopathy,whether diabetic corneal neuropathy precedes diabetic retinopathy,as well as the relation between the stage of diabetic retinopathy and the severity of corneal *** also endeavor to explore the relevance of a corneal screening in diabetic eyes and the possibility of using corneal nerve measurements to monitor the progression of diabetic retinopathy.

关键词： cornea corneal nerves diabetes diabetic corneal neuropathy diabetic retinopathy retina

Ammonia pyrolysis oxidation excited by nanosecond pulsed discharge:Global/fluid models hybrid solution

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Journal of Energy chemistry 2025年第1期100卷 385-396页

作者： Mingming Zhang Hanyu Wu Qi chen Jiaxin Yang Bonan liu School of Mechanical Electronic and Control Engineering Beijing Jiaotong University china University of Petroleum

The kinetic characteristics of plasma-assisted oxidative pyrolysis of ammonia are studied by using the global/fluid models hybrid solution ***,the stable products of plasma-assisted oxidative pyrolysis of ammonia are *** results show that the consumption of NH3/O2and the production of N2/H2change linearly with the increase of voltage,which indicates the decoupling of nonequilibrium molecular excitation and oxidative pyrolysis of ammonia at low ***,the detailed reaction kinetics mechanism of ammonia oxidative pyrolysis stimulated by a nanosecond pulse voltage at low pressure and room temperature is *** on the reaction path analysis,the simplified mechanism is *** detailed and simplified mechanism simulation results are compared with experimental data to verify the accuracy of the simplified ***,based on the simplified mechanism,the fluid model of ammonia oxidative pyrolysis stimulated by the nanosecond pulse plasma is established to study the pre-sheath/sheath behavior and the resultant consumption and formation of key *** results show that the generation,development,and propagation of the pre-sheath have a great influence on the formation and consumption of *** consumption of NH3by the cathode pre-sheath is greater than that by the anode pre-sheath,but the opposite is true for OH and O（1S）.However,within the sheath,almost all reactions do not ***,by changing the parameters of nanosecond pulse power supply voltage,it is found that the electron number density,electron current density,and applied peak voltages are not the direct reasons for the structural changes of the sheath and ***,the discharge interval has little effect on the sheath structure and gas mixture *** research results of this paper not only help to understand the kinetic promotion of non-equilibrium excitation in the process of oxidative pyrolysis but also help to explore th

关键词： Nanosecond pulsed discharge Ammonia Oxidative pyrolysis fluid model Global model

Micro-strain regulation strategy to stabilize perovskite lattice based on the categories and impact of strain on perovskite solar cells

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Journal of Energy chemistry 2025年第1期100卷 578-604页

作者： caixia Li Wenwu liu Shiji Da Lingbin Kong fen Ran State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology School of Materials Science and Engineering Lanzhou University of Technology

Photovoltaic metal halide perovskite solar cells(PScs) convert light to electricity more efficiently than crystalline silicon cells, and the cost of materials used to make them is lower than that of silicon *** efficiency is not a core issue affecting the application of perovskite solar cells in special *** present, stability is the major technical encounters that hinders its further commercial development. Microstrain in PScs is currently a significant factor responsible for the device's instability. Strain-induced ion migration is widely believed to accelerate perovskite degradation even when external stimuli are ***, it is imperative to study strain to enhance the stability of PScs. This paper reviews recent developments to understand strain's origin and effect mechanisms on performance of PScs, including ion migration,failure behavior, defect formation, and its effect on photoelectric properties, stability, and ***, several well-known strain management strategies are systematically introduced based on the strain effect mechanism and strain engineering on the film, providing more clues for further preparation with increased stability. The manipulation of external physical strain applied from films to entire devices has been extensively studied. furthermore, recommendations for future research directions and chemical approaches have been provided. It is emphasized that strain engineering plays a crucial role in improving the efficiency and longevity of PScs. Tensile strain causes rapid degradation, while moderate compressive strain and external strain control could improve properties and stability. Efforts should focus on controlling compressive strain to mitigate residual tensile strain and introducing it in a controlled manner. future research endeavors may focus on exploring these pathways to improve the efficiency and lifespan of PScs.

关键词： Halide perovskite solar cells Strain origins Strain effects Strain management