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Microstructure Evolution and Strain-Dependent Constitutive Modeling to Predict the Flow Behavior of 20Cr–24Ni–6Mo Super-Austenitic Stainless Steel During Hot Deformation

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Acta Metallurgica Sinica(English Letters) 2018年第4期31卷 401-414页

作者： Yan-Sen Hao wan-chun liu Zhen-Yu liu State Key Laboratory of Rolling and Automation Northeastern University

Hot compression tests were carried out with specimens of 20Cr-24Ni-6Mo super-austenitic stainless steel at strain rate from 0.01 to 10 s^-1 in the temperature range from 950 to 1150 ℃,and flow behavior was *** analysis indicated that dynamic recrystallization（DRX）behavior was more sensitive to the temperature than strain rate,and full DRX was obtained when the specimen deformed at 1150℃.When the temperature reduced to 1050 ℃,full DRX was completed at the highest strain rate 10 s-l rather than at the lowest strain rate 0.01 s-1 because the adiabatic heating was pronounced at higher strain *** addition,flow behavior reflected in flow curves was inconsistent with the actual microstructural evolution during hot deformation,especially at higher strain rates and lower ***,flow curves were revised in consideration of the effects of adiabatic heating and friction during hot *** results showed that adiabatic heating became greater with the increase of strain level,strain rate and the decrease of temperature,while the frictional effect cannot be neglected at high strain ***,based on the revised flow curves,strain-dependent constitutive modeling was developed and verified by comparing the predicted data with the experimental data and the modified *** result suggested that the developed constitutive modeling can more adequately predict the flow behavior reflected by corrected flow curves than that reflected by experimental flow curves,even though some difference existed at 950℃ and 0.01 s^-*** main reason was that plenty of precipitates generated at this deformation condition and affected the DRX behavior and deformation behavior,eventually resulted in dramatic increase of deformation resistance.

关键词： Super-austenitic stainless steel Hot compression Adiabatic heating Constitutive modeling Microstructure evolution

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On microstructure characterization of Fe-Cr-Ni-Mo-N super-austenitic stainless steel during hot deformation

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Journal of Iron and Steel Research International 2019年第10期26卷 1080-1087页

作者： Yan-sen Hao Jian Li wan-chun liu Wei-na Zhang Zhen-yu liu State Key Lab for Rolling Technologies and Automation Northeastern UniversityShenyang 110819LiaoningChina

Hot compression tests of Fe-Cr-Ni-Mo-N super-austenitic stainless steel were carried out in the temperature range of 950-1150℃with a strain rate of 0.01-10 s-1,in which dynamic recrystallization(DRX)mechanisms and coincident site lattice(CSL)boundary evolution in consideration of adiabatic heating were *** results show that discontinuous DRX was the main DRX *** to the high stacking fault energy(162-173 mJ/m2),subgrain evolution occurring in dynamic recovery process was stimulated at high temperatures and high strain *** behavior was accelerated by higher strain rate and adiabatic ***,amounts of fine annealing twin boundaries were observed in the specimens deformed at higher strain rates and higher *** analyzing the length fractions of∑3 boundary in overall boundaries and in CSL boundaries,the results indicate that∑3 regeneration mechanism and new twinning mechanism take effect concurrently for twin-related grain boundary when the specimens were deformed at 950℃with a strain rate of 0.01-10 *** increasing strain rate or deformation temperature,the propagation of∑3 boundaries was mainly dominated by new twinning mechanism.

关键词： Super-austenitic stainless steel Dynamic recrystallization Adiabatic heating Coincident site lattice boundary Hot deformation

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LOCALIZED MOLECULAR ORBITAL STUDY ON ELECTRONIC STRUCTURES OF BOWL-SHAPED AROMATIC HYDROCARBONS

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Chinese Chemical Letters 1993年第11期4卷 963-964页

作者： Zhi Da CHEN chun wan liu Jia Xi LU Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences State Key Laboratory of Structural Chemistry, Fuzhou, Fujian 350002

The localized molecular orbitals for typical bowl-shaped circulenes are obtained by the use of INDO-LMO method. It is found that these bowl-shaped circulenes with strained π-electron systems are still aromatic and th... 详细信息

关键词： In LOCALIZED MOLECULAR ORBITAL STUDY ON ELECTRONIC STRUCTURES OF BOWL-SHAPED AROMATIC HYDROCARBONS 工工

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New types of singular solutions of conformal Q-curvature equations

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Acta Mathematica Sinica,English Series 2025年

作者： Zongming Guo Zhongyuan liu Fangshu wan Department of Mathematics Henan Normal University School of Mathematics and Statistics Henan University School of Mathematical Sciences Anhui University

We construct radial and non-radial singular solutions u ∈ C4（B{0}） with a non-removable singular point x = 0 for the conformal Q-curvature equation:■where B = {x ∈ R4: |x| D0≥ 0, and satisfying ■Moreover, detailed asymptotic expansions near x = 0 of these radial and non-radial singular solutions can be established. As an application, we can also obtain the existence of two types of solutions u ∈ C4（R4■） to the problem ■ satisfying |x|-2u（x） →-D D0, and satisfying u（x） = o（|x|2） uniformly as |x| → ∞.

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Preparation of Modified Composite Nanofiltration Membrane Synergistically Using Carboxylic Multi- walled Carbon Nanotube and β-cyclodextrin

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 232-239页

作者： liu Peng MAO Junpeng FANG Yanfeng YU Yunwu CHEN Changxiu TANG Ning wan Ye GU Yaxin liu Yunxue wanG Lihua School of Materials Science and Engineering Shenyang Jianzhu UniversityShenyang 110168China

A new modified blend ultrafiltration(UF)membrane with good hydrophilicity,high porosity and excellent anti-fouling performance was developed by using carboxylic multi-walled carbon nanotube(CMWCNT)as casting solution ***,a composite nanofiltration(NF)membrane with large water flux and good retention rate was fabricated by using the PVDF/CMWCNT blend UF membrane as the substrate,and polyvinyl alcohol(PVA),β-cyclodextrin(β-CD)and polyethylenimine(PEI)as the coating *** results show that with the appropriate addition of CMWCNT in the casting solution,the surface roughness,porosity and recovery rate of the PVDF/CMWCNT blend UF membrane is obviously *** water flux of blend UF membrane is significantly improved when the CMWCNT content increases from 0 wt%to 0.2 wt%.The water flux of blend UF membrane with 0.2 wt%CMWCNT is 162.7 L/(m^(2)·h),which is 44.3%higher than that of the pure PVDF ***β-CD content is 0.8 wt%,the retention rate of Congo red by PVDF/CMWCNT/β-CD composite NF membrane reaches 98.7%,which is 28.3%higher than that of single PVA/PEI modified *** research will provide a new idea and simple method for developing novel high-performance composite NF membranes.

关键词： CMWCNT cyclodextrin nanofiltration membrane

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Direct and rapid detection of serum amino acid and monoamine neurotransmitters to assist the diagnosis of panic disorder

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Science China Chemistry 2025年第1期68卷 377-384页

作者： Shiwen liu Xuerui wan Meng Zhao Jiaqi wang Weilan Wu Linlin You Yonggui Yuan Qian Xu Rong Gao Key Laboratory of Environmental Medicine Engineering Ministry of Education School of Public Health Southeast University Key Laboratory of Modern Toxicology of Ministry of Education Department of Hygienic Analysis and Detection School of Public HealthNanjing Medical University Department of Psychosomatics and Psychiatry Zhongda Hospital School of Medicine Southeast University

The measurement of amino acid and monoamine neurotransmitters（NTs） in serum plays a central role in the identification and monitoring of clinical panic disorder（PD）. However, the strong polarity and chemical heterogeneity of NTs make direct extraction and rapid detection extremely challenging. Herein, we developed a strategy that integrated solid phase extraction based on magnetic Fe3O4coated with polydopamine（Fe3O4@PDA） and direct analysis of mass spectrometry in real time（DART-MS） for quantification of 10 NTs. We systematically investigated the optimal conditions of this strategy to achieve good accuracy and precision. Compared with existing magnetic solid phase extraction methods for NTs detection in biological samples, this strategy could adsorb more targets while having similar adsorption efficiencies, and the total process time was reduced by an average of 69.42%. We rapidly determined the metabolic abnormality of 6 types of NTs in the serum of PD patients and demonstrated their diagnostic accuracy. In addition, an outstanding feature of PD in which tryptophan was more metabolized by the KYN pathway and the 5-hydroxytryptamine pathway was inhibited could be elucidated by this strategy. Our results highlighted the potential ability of Fe3O4@PDA coupled with DART-MS to assist in the clinical diagnosis of PD.

关键词： neurotransmitters panic disorder magnetic solid phase extraction direct analysis of mass spectrometry in real time

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Propagating subduction initiation of the Caroline Plate at the Mussau Trench

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Science China Earth Sciences 2025年第1期68卷 253-269页

作者： chun-Feng LI Yongkang DENG Tao WU Dongdong DONG Guoliang ZHANG Jiazheng ZHANG Yutao liu Yaqing LI Fugui TANG Lulu ZHANG Department of Marine Sciences Zhejiang University Laboratory of Marine Mineral Resources Laoshan Laboratory Key Lab of Marine Geology and Environment Institute of Oceanology Chinese Academy of Sciences Key Lab of Ocean and Marginal Sea Geology South China Sea Institute of Oceanology Chinese Academy of Sciences Science & Technology on Integrated Information System Lab Institute of Software Chinese Academy of Sciences

New seismic imaging from the Mussau Trench confirms that, under horizontal compression on an oceanic plate boundary, it is within the young and weak oceanic plate that a trench will develop, and it is the young plate, not so long after its birth, that starts to subduct toward the old plate. The Mesozoic Pacific Plate cannot easily bend, under the joint horizontal compression and vertical gravity pull, even with a pre-existing weak zone in place and with a large age offset across the plate boundary. The bending of the Caroline Plate near the northern end of the Mussau Trench started only after a long-time span of trench migration, and/or after a prolonged transition from initial compression to trench development. Highly contrasting trench deformation and sedimentary accretion between two parallel seismic sections support an evident migration of underthrusting or significant longitudinal heterogeneity along the trench. The swift transition from underthrusting to non-thrusting can be explained by a counter-clockwise rotation of the Caroline Plate. That miniature accretionary wedges develop even before the subduction initiates imply strong compression and uplifting before the underthrusting can kick-start. Rotation of the Caroline Plate have been halted as the Mussau Trench is seismically rather quiet and the Lyra Trough to the east shows relaxational extension.

关键词： Mussau Trench Subduction initiation Seismic reflection Caroline Plate

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Effects of water level variations on the water quality of Huayang Lakes, China

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Journal of Geographical Sciences 2025年第1期35卷 173-188页

作者： AN Lesheng liu chun FAN Zhongya LIAO Kaihua wanG Wencai wanG Nan School of Resources and Environment Anqing Normal University South China Institute of Environmental Sciences Ministry of Ecology and Environment The Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and LimnologyCAS

To explore water level variations and their dynamic influence on the water quality of Huayang Lakes, the water level from 1967 to 2023 and water quality from 2015 to 2023 were analyzed using the Mann–Kendall trend test, box plots, and violin plots. The results show a notable hydrological rhythm of water level alternation between dry and flood seasons in Huayang Lakes, with an average water level of 12.82 m and a monthly range of 11.21–17.24m. Since 2017, the water level of Huayang Rivers has shown a decreasing trend of –0.02 m/*** phosphorus(TP) has become the primary pollutant. The TP concentrations in Longgan Lake(the largest lake) during the dry, rising, flood, and retreating seasons from 2015 to 2023were 0.083, 0.061, 0.050, and 0.059 mg/L, respectively. The effect of water level on TP was mainly observed during the low-water period. When the water level in the dry season rose to 12.25 and 13.00 m, the percentage of TP exceeding 0.1 mg/L in Longgan Lake decreased to 55.8% and 33.3%, respectively. During the dry season, wind and wave disturbances caused the release of endogenous phosphorus in Huayang Lakes. This led to drastic fluctuations in TP concentration, reducing the correlation between water level and TP. When external control is limited, the water level during the dry season should be maintained between 12.25 and 13.0 m. Additionally, it is necessary to accelerate the restoration of submerged macrophyte species(such as Hydrilla verticillata and Vallisneria natans) in the Huayang Rivers.

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Formation and evolution of supercritical geofluid

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Science China Earth Sciences 2025年第1期68卷 39-51页

作者： Huaiwei NI Yilin XIAO Xiaolin XIONG Xiandong liu chunxiao GAO Yi-Xiang CHEN Yunguo LI wan-Cai LI Xuan GUO Yang-Yang wanG Dong-Bo TAN Li ZHANG State Key Laboratory of Lithospheric and Environmental Coevolution University of Science and Technology of China Deep Space Exploration Laboratory/School of Earth and Space Sciences University of Science and Technology of China Guangzhou Institute of Geochemistry Chinese Academy of Sciences School of Earth Sciences and Engineering Nanjing University State Key Lab of Superhard Materials Jilin University

In this work, we provide a comprehensive review on the formation, evolution, properties, and effects of supercritical geofluid. In Earth's interior, enhanced miscibility between H2O and silicate by the addition of special components or by the increase of pressure and temperature gives rise to supercritical geofluid with a significant amount of both H2O and silicate *** formation of supercritical geofluid in magmatic-hydrothermal systems, typified by pegmatite system, is governed by meltfluid critical curve. The formation of supercritical geofluid in metamorphic systems, typified by subducted slab, is governed by the second critical end point. Experimental results suggest that the presence of boron and fluorine in pegmatite system makes it possible to form supercritical geofluid at crustal depths, but the release of supercritical geofluid from subducted slab is withheld until almost 100 km depth. A major presence of both H2O and depolymerized structural units（monomers, dimers, etc.） endows supercritical geofluid with unique physical properties including low density, low elastic moduli, low viscosity, high diffusivity,and high electrical conductivity. Supercritical geofluid can effectively mobilize a variety of elements even including high field strength elements and heavy rare earth elements. The chemical signatures of supercritical geofluid can be inherited by metasomatized mantle and mantle-derived melts, and this could give an explanation of the oxidation of arc magmas. Phase separation of supercritical geofluid through the mechanism of spinodal decomposition leads to formation of a melt network. Multiphase fluid inclusions recovered from subduction zone rocks and pegmatites are possible relics of supercritical geofluid. Supercritical geofluid can cause electrical anomaly and low seismic velocity near the top of subducted slab, and can be linked with intermediate-focus earthquakes. Supercritical geofluid may have played a crucial role in the formation of pe

关键词： Supercritical geofluid Miscibility Subduction zone Pegmatite

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Chiral phosphoramidite ligand-modulated palladium auto-tandem catalysis for asymmetric dehydrogenative dienylation of imines with α-alkenes

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Science China Chemistry 2025年

作者： Zhong-Sheng Nong Hao-Fan Qian Ying-chun Chen Pu-Sheng wang liu-Zhu Gong Hefei National Research Center for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of China Key Laboratory of Drug Targeting and Drug Delivery System (Sichuan University) Ministry of Education and Sichuan Research Center for Drug Precision Industrial Technology West China School of Pharmacy Sichuan University School of Materials and Chemistry Southwest University of Science and Technology

The development of efficient processes allowing rapid access to complex chiral molecules from easily available alkenes is a long-term pursuit in the synthetic chemistry community. Transition metal-catalyzed asymmetric functionalization of allylic C–H bond represents a unique alternative toward this goal. However, enantioselective dehydrogenative transformation of olefins to value-added optically enriched molecules remains yet to be discovered. Here, we report a highly enantioselective dehydrogenative dienylation of imines with unactivated α-alkenes driven by the synergistic action of palladium complex and carboxylic acid. Chiral phosphoramidite ligands turned out to be superior in modulating the performance of palladium autotandem catalysis and allowed a broad range of α-alkenes and imines to be transformed into chiral dienylamines. Mechanistic studies suggest that the dienes could be in situ generated from α-alkenes through a palladium(0)-mediated dehydrogenative process in the presence of excess benzoquinone oxidants, and then participated in the Pd-chiral phosphoramidite-catalyzed intermolecular vinylogous-type addition to the imines activated by the carboxylic acid co-catalyst. Notably, the second β-H elimination occurring in the dienylation event might be the turnover-limiting step.

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