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Permafrost changes in the Nanwenghe Wetlands Reserve on the southern slope of the Da Xing'anling‒Yile'huli mountains,Northeast China

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Advances in Climate change Research 2021年第5期12卷 696-709页

作者： HE Rui-Xia JIN Hui-Jun LUO Dong-Liang LI Xiao-Ying ZHOU Chuan-Fang JIA Ning JIN Xiao-Ying LI Xin-Yu CHE Tao YANG Xue WANG Li-Zhong LI wei-Hai wei chang-lei chang Xiao-Li YU Shao-Peng State Key Laboratory of Frozen Soils Engineering and Da Xing'anling Observation and Research Station of Frozen-Ground Engineering and Environment Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou73000China Institute of Cold Regions Science and Engineering School of Civil EngineeringNortheast-China Observatory and Research-Station of Permafrost Geo-Environment(Ministry of Education)and Northeast Forestry UniversityHarbin150040China School of Geography and Tourism Harbin UniversityHarbin150086China Harbin Center for Natural Resources Survey Geological Survey of ChinaHarbin150086China School of Civil Engineering Harbin Institute of TechnologyHarbin150090China China Forest Ecological Research Network(CFERN)Station at the Headwater Area of Nenjiang River Daxing'anling Institute of Agriculture and ForestryDaxing'anling Forestry GroupJagdaqi165100China National-Local Joint Engineering Laboratory of Geo-Spatial Information Technology Hunan University of Science and TechnologyXiangtan411201China

The Nanwenghe Wetlands Reserve in the Yile'huli Mountains is a representative region of the Xing'an *** response of permafrost to climate change remains unclear due to limited field ***,longer-term responses of the ground thermal state to climate change since 2011 have been monitored at four sites with varied surface characteristics:Carex tato wetland(P1)and *** wetland(P2)with a multi-year average temperatures at the depth of zero annual amplitude(T_(ZAA))of−0.52 and−1.19℃,respectively;Betula platyphylla-Larix gmelinii(Rupr.)Kuzen mixed forest(P3)with T_(ZAA) of 0.17℃,and;the forest of ***(Rupr.)Kuzen(P4)with T_(ZAA) of 1.65℃.Continuous observations demonstrate that the ecosystem-protected Xing'an permafrost experienced a cooling under a warming *** temperature at the top of permafrost(TTOP)rose(1.8℃ per decade)but the TZAA declined(−0.14℃ per decade),while the active layer thickness(ALT)thinned from 0.9 m in 2012 to 0.8 m in 2014 at *** the TTOP and TZAA increased(0.89 and 0.06℃ per decade,respectively),but the ALT thinned from 1.4 m in 2012 to 0.7 m in 2016 at *** detached permafrost at P3 disappeared in summer 2012,with warming rates of+0.42 and+0.17℃ per decade for TTOP and T_(ZAA),***,up to date,the ground thermal state has remained stable at *** conclude that the thermal offset is crucial for the preservation and persistence of the Xing'an permafrost at the southern fringe.

关键词： Nanwenghe wetland reserve Permafrost Climate change Active layer thickness Ground thermal state Thermal offset Local environmental factors

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Dynamic Analysis of A Deepwater Drilling Riser with A New Hang-off System

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China Ocean Engineering 2024年第1期38卷 29-41页

作者： LI Yan-wei LIU Xiu-quan WANG Jin-long CHEN Guo-ming chang Yuan-jiang SHENG lei-xiang Centre for Offshore Engineering and Safety Technology China University of PetroleumQingdao 266580China National Engineering Laboratory of Offshore Geophysical and Exploration Equipment China University of PetroleumQingdao 266580China China CNOOC Research Institute Co. Ltd.Beijing 100028China

The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of *** approach leads to a challenging problem:coupling the dynamics of risers with a new hang-off system combined with multiple structures and complex *** accurately analyze the dynamic responses of the coupled system,a coupled dynamic model is established based on the Euler-Bernoulli beam-column theory and penalty function method.A comprehensive analysis method is proposed for coupled dynamic analysis by combining the finite element method and the Newmarkβ*** analysis program is also developed in MATLAB for dynamic *** simulation results show that the dynamic performances of the risers at the top part are significantly improved by the new hang-off system,especially the novel design,which includes the centralizer and articulation *** bending moment and lateral deformation of the risers at the top part decrease,while the hang-off joint experiences a great bending moment at the bottom of the lateral restraint area which requires particular attention in design and *** platform navigation speed range under the safety limits of risers expands with the new hang-off system in use.

关键词： deepwater drilling riser new hang-off system dynamic analysis finite element method penalty function method

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Martensitic transformation pathways and crystallographic orientation relationships in steel

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Journal of Materials Science & Technology 2024年第7期174卷 74-84页

作者： Tian-wei Liu Xiao-lei Wu State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Martensite is one of the most important structures determining the ability to tailor the performance of steel and several other engineering *** previous studies,the face-centered cubic(FCC)to hexag-onal close-packed(HCP)(or body-centered cubic(BCC))martensitic transformation and the FCC to body-centered tetragonal(BCT)(or BCC)martensitic transformation during deformation and quenching were widely investigated;these transformations usually improve the plasticity and strength of steel,*** this work,detailed transmission electron microscopy(TEM)observations and electron diffraction pattern analyses of the BCT and BCC twins are performed along the[110],[131],and[¯153]zone *** transformation of BCT twins into BCC twins along the[131]zone axis is also analyzed through in situ heating during the TEM *** high-resolution TEM observations of mutually perpendicular BCT variants are consistent with the atomic arrangement obtained for the quenching pathway during the martensitic *** addition,different orientation relationships between austenite and marten-site are explained in terms of the atomic migration occurring during the deformation pathway and the quenching pathway of the martensitic transformation.

关键词： Body-centered tetragonal twin Martensitic transformation Steel Transmission electron microscopy Orientation relationship

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Cyclohexanol optimizes Pt/ionomer interface in fuel cell cathodes

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Science China Chemistry 2024年第2期67卷 417-419页

作者： lei Tong Hai-wei Liang Hefei National Research Center for Physical Sciences at the Microscale Department of ChemistryUniversity of Science and Technology of ChinaHefei230026China

This highlight is based on a recent article published in Nature Catalysis, in which wei's group [1] from Chongqing University proposes a novel approach to enhance the performance of proton exchange membrane fuel cells(PEMFCs)by adjusting the interface between Pt and ionomer in the cathode catalyst layer. Their strategy involves adding cyclohexanol to the cathode catalyst ink to impede the adsorption of sulfonate groups from the ionomer onto Pt nanoparticles, which results in the release of Pt activity sites and a significant improvement in the mass transport efficiency.

关键词： interface catalyst adding

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Core-shell mesoporous carbon hollow spheres as Se hosts for advanced Al-Se batteries

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 899-906页

作者： Haiping lei Tianwei wei Jiguo Tu Shuqiang Jiao State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Incorporating a selenium(Se)positive electrode into aluminum(Al)-ion batteries is an effective strategy for improving the overall battery ***,the cycling stability of Se positive electrodes has challenges due to the dissolution of intermediate reaction *** this work,we aim to harness the advantages of Se while reducing its limitations by preparing a core-shell mesoporous carbon hollow sphere with a titanium nitride(C@TiN)host to load 63.9wt%Se as the positive electrode material for Al-Se *** the physical and chemical confinement offered by the hollow mesoporous carbon and TiN,the obtained core-shell mesoporous carbon hollow spheres coated with Se(Se@C@TiN)display superior utilization of the active material and remarkable cycling *** a result,Al-Se batteries equipped with the as-prepared Se@C@TiN composite positive electrodes show an initial discharge specific capacity of 377 mAh·g^(-1)at a current density of 1000 mA·g^(-1)while maintaining a discharge specific capacity of 86.0 mAh·g^(-1)over 200 *** improved cycling performance is ascribed to the high electrical conductivity of the core-shell mesoporous carbon hollow spheres and the unique three-dimensional hierarchical architecture of Se@C@TiN.

关键词： aluminum-selenium batteries intermediate products core-shell mesoporous carbon hollow sphere cycling performance

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Effects of Number of Bleed Holes on Shock-Wave/Boundary-Layer Interactions in a Transonic Compressor Stator

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Journal of Thermal Science 2024年第2期33卷 611-624页

作者： LI Bai ZHOU Xun LUO lei DU wei School of Energy Science and Engineering Harbin Institute of TechnologyHarbin150001China

An extensive numerical investigation is conducted to characterize the flow separation control in a transonic compressor cascade with a porous *** bleed holes are arranged on the suction surface in a single row,two staggered rows and three staggered *** each bleed scheme,five bleed pressure ratios are examined at an inlet Mach number of *** results indicate that the aerodynamic performance of the cascade is significantly improved by the porous *** the single-row scheme,the maximum reduction in total pressure losses is 57%.For the two-staggered-row and three-staggered-row schemes,there is an optimal bleed pressure ratio of 1.0,and the maximum reductions in total pressure loss are 68% and 75%,*** low loss in the cascade is due to the well-controlled boundary *** new local supersonic region created by the bleed hole is the key reason for the improved boundary *** vortex induced by side bleeding provides another mechanism for delaying flow *** the bleed holes could create multiple local supersonic regions,which reduce the range of the adverse pressure gradient that the boundary layer needs to *** is the reason why cascades with more bleed holes perform better.

关键词： transonic compressor stator shock wave/boundary layer interaction porous bleed number of bleed holes

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Performance analysis and multi-objective optimization based on a modified irreversible Stirling cycle

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Science China(Technological Sciences) 2024年第6期67卷 1668-1684页

作者： XU lei YU MinJie LIU ZhiChun LIU wei School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan430074China

The efficiency of the actual Stirling engine is much lower than the ideal Carnot cycle *** obtain more precise efficiency for Stirling engines,this paper proposes a modified Stirling cycle with a more accurate heat transfer process in Stirling engines based on a thermodynamic function called available *** finite-time thermodynamic method is used to analyze the model performance under constant heat source temperature,finite temperature difference heat transfer,and incomplete regenerative processes.A new polytropic process is introduced to model the heat transfer between the working fluid and external heat sources in which only heat above ambient temperature is converted into technical *** regenerator is divided into numerous smaller heat reservoirs with individual temperature to analyze the incomplete regenerative *** expressions of the output power and thermal efficiency are obtained based on the modified irreversible Stirling cycle,and the effects of irreversible losses are analyzed to evaluate the performance of the proposed *** indicate that the efficiency of the modified cycle is much lower than that of the ideal Stirling cycle with an isothermal *** the increase of the average heat transfer temperature difference,there exists an optimum value for the power of the irreversible *** optimum power of the model was obtained for varying thermodynamic parameters by optimizing the average heat transfer temperature difference between the hot and cold *** optimize the irreversible model,the multi-objective optimization analysis is carried out based on NSGA-Ⅱ,which results in an optimized output power of 40.87 kW and an optimized thermal efficiency of 44%.

关键词： stirling cycle regenerative processes isopotential processes multi-objective optimization finite time thermodynamics

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An effective strategy of constructing multi-metallic oxides of ZnO/ CoNiO_(2)/CoO/C microflowers for improved supercapacitive performance

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Chinese Journal of Chemical Engineering 2024年第3期67卷 1-8页

作者： wei Guo Yan Zhang Xiaxin lei Shuang Wang College of Physics Taiyuan University of TechnologyJinzhong 030600China College of Environmental Science and Engineering Taiyuan University of TechnologyJinzhong 030600China Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization Taiyuan University of TechnologyTaiyuan 030024China

In this work,a new ZnO/CoNiO_(2)/CoO/C metal oxides composite is prepared by cost-effective hydrothermal method coupled with annealing process under N_(2) ***,the oxidation-defect annealing environment is conducive to both morphology and component of the composite,which flower-like ZnO/CoNiO_(2)/CoO/C is *** from good chemical stability of ZnO,high energy capacity of CoNiO_(2) and CoO and good conductivity of C,the as-prepared sample shows promising electrochemical behavior,including the specific capacity of 1435 C·g^(-1) at 1 A·g^(-1),capacity retention of 87.3%at 20 A·g^(-1),and cycling stability of 90.5%for 3000 cycles at 5 A·g^(-1),***,the prepared ZnO/CoNiO_(2)/CoO/C/NF//AC aqueous hybrid supercapacitors device delivers the best specific energy of 55.9 W·h·kg^(-1) at 850 W·kg^(-1).The results reflect that the as-prepared ZnO/CoNiO_(2)/CoO/C microflowers are considered as high performance electrode materials for supercapacitor,and the strategy mentioned in this paper is benefit to prepare mixed metal oxides composite for energy conversion and storage.

关键词： Composites Electrochemistry Hydrothermal Transition metal oxides Structural control Supercapacitors

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Modulated-ISRJ rejection using online dictionary learning for synthetic aperture radar imagery

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Journal of Systems Engineering and Electronics 2024年第2期35卷 316-329页

作者： wei Shaopeng ZHANG lei LU Jingyue LIU Hongwei College of Oceanography and Space Informatics China University of Petroleum(East China)Qingdao 266580China School of Electronics Engineering Xidian UniversityXi’an 710071China School of Electronics and Communication Engineering Shenzhen Campus of Sun Yat-sen UniversityGuangzhou 518107China School of Computer Science and Technology Xidian UniversityXi’an 710071China

In electromagnetic countermeasures circumstances,synthetic aperture radar(SAR)imagery usually suffers from severe quality degradation from modulated interrupt sampling repeater jamming(MISRJ),which usually owes considerable coherence with the SAR transmission waveform together with periodical modulation *** paper develops an MISRJ suppression algorithm for SAR imagery with online dictionary *** the algorithm,the jamming modulation temporal properties are exploited with extracting and sorting MISRJ slices using fast-time *** dictionary learning is followed to separate real signals from jamming *** the learned representation,time-varying MISRJs are suppressed *** simulated and real-measured SAR data are also used to confirm advantages in suppressing time-varying MISRJs over traditional methods.

关键词： synthetic aperture radar(SAR) modulated interrupt sampling jamming(MISRJ) online dictionary learning

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Proteomic response of Phaeocystis globosa to nitrogen limitation

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Journal of Oceanology and Limnology 2024年第1期42卷 141-149页

作者： Haisu LIU Ruiwang wei Qiangyong lei lei CUI Songhui LÜ Key Laboratory of Eutrophication and Red Tide Prevention Research Center for Harmful Algae and Marine BiologyJinan UniversityGuangzhou 510632China Southern Marine Science and Engineering Guangdong Laboratory Zhuhai 519082China National Engineering Laboratory of Electronic and Information Standardization Shenzhen 518057China

Phaeocystis globosa is an important unicellular eukaryotic alga that can also form *** can cause massive harmful algal blooms and plays an important role in the global carbon or sulfur *** far,the ecophysiology of *** has been investigated by numerous ***,the proteomic response of *** to nitrogen depletion remains largely *** compared four protein preparation methods of *** for two-dimensional electrophoresis(2-DE)(Urea/Triton X-100 with trichloroacetic acid(TCA)/acetone precipitation;TCA/acetone precipitation;Radio Immuno Precipitation Assay(RIPA)with TCA/acetone precipitation;and Tris buffer).Results show that the combination of RIPA with TCA/acetone precipitation had a clear gel background and showed the best protein spot separation effect,based on which the proteomic response to nitrogen depletion was studied using *** addition,we identified six differentially expressed proteins whose relative abundance increased or decreased more than 1.5-fold(P<0.05).Most proteins could not be identified,which might be attributed to the lack of genomic sequences of *** nitrogen limitation,replication protein-like,RNA ligase,and sn-glycerol-3-phosphate dehydrogenase were reduced,which may decrease the DNA replication level and ATP production in *** *** increase of endonucleaseⅢand transcriptional regulator enzyme may affect the metabolic and antioxidant function of *** cells and induce cell *** findings provide a basis for further proteomic study of *** and the optimization of protein preparation methods of marine microalgae.

关键词： Phaeocystis globosa nitrogen limitation proteomic response two-dimensional electrophoresis

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