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Satellite Navigation 2024年第1期5卷 224-239页

作者： Paipai Wu wenfeng Nie Yangfan Liu Tianhe xu Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai264209ShandongChina Research Group of Astronomy and Geomatics(gAGE) Universitat Politecnica de Catalunya(UPC)BarcelonaSpain

Underwater acoustic Long-Baseline System(LBL)is an important technique for submarine positioning and ***,the high cost of the seafloor equipment and complex construction of a seafloor network restrict the distribution of the LBL within a small area,making an underwater vehicle difficult for long-distance and high-precision acoustic-based or inertial-based *** therefore propose an acoustic LBL-based Inertial Measurement Unit(IMU)calibration *** the underwater vehicle can receive the acoustic signal from a seafloor beacon,the IMU is precisely calibrated to reduce the cumulative error of Strapdown Inertial Navigation System(SINS).In this way,the IMU is expected to maintain a certain degree of accuracy by relying solely on SINS when the vehicle reaches out the range of the LBL network and cannot receive the acoustic *** present the acoustic LBL-based IMU online calibration model and analyze the factors that affect the accuracy of IMU *** results fulfill the expectation that the gyroscope bias and accelerometer bias are the main error sources that affect the divergence of SINS position errors,and the track line of the underwater vehicle directly affects the accuracy of the calibration *** addition,we deduce that an optimal calibration trajectory needs to consider the effects of the three-dimensional observability and position dilution of *** the experiment,we compare the effects of seven calibration trajectories:straight and diamond-shaped with and without the change of depth,and three sets of curves with the change of depth:circular,S-shaped,and *** them,we find that the figure-eight is the optimal trajectory for acoustic LBL-based IMU online *** take the maintenance period during which the accumulated SINS Three Dimensional(3D)position errors are below 1 km to evaluate the calibration *** filed experimental results show that for the Micro-electromechanical System

关键词： Acoustic LBL Online IMU calibration SINS Relay reference network

Surface integrity evolution during creep feed profile grinding ofγ-TiAl blade tenon

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Chinese Journal of Aeronautics 2024年第8期37卷 496-512页

作者： Tao CHEN Xiaowei WANG Biao ZHAO wenfeng DING Jiuhua xu National Key Laboratory of Science and Technology on Helicopter Transmission Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Gamma titanium-aluminum(γ-TiAl)intermetallic compounds are increasingly used in manufacturing key hot-end components(e.g.,blade tenon)in aero engines due to their high specific strength and lightweight *** feed profile grinding(CFPG)as a crucial precision process that is applied to produce the final profile of the blade ***,sudden surface burns and microcracks of machined c-TiAl blade tenon often occur because of its low plasticity and high strength during grinding processes,leading to poor surface *** this work,CFPG experiments based on the profile characteristics ofγ-TiAl blade tenon were performed and an associated undeformed chip thickness model considering grain–workpiece contact condition was established to explore the evolution of the surface ***,the surface integrity was analyzed at different positions of the blade tenon in terms of surface roughness and morphology,metallographic structure,microhardness,and residual *** show that the profile characteristics of blade tenon have a significant influence on machined surface integrity because of the thermomechanical effect at various detecting *** residual stress was established based on the undeformed chip thickness model considering the profile structure,with a prediction error of 10%–15%.The thermomechanical effect is more obvious at the bottom area,where the surface roughness,work hardening degree,and subsurface plastic deformation range are the largest,while the values at the bevel area are the *** on the undeformed chip thickness model,a residual stress finite element simulation was conducted by employing thermomechanical coupled *** addition,the error between the simulation and the experiment was between 10%–15%.Strain and strain rate equations were established through the relationship between material displacement and *** average strain and strain rate of the ground surface when ap is 1.0 mm are 18.8%and 33.2%l

关键词： Gamma titanium-aluminum intermetallic compounds Blade tenon Creep feed profile grinding Surface integrity Thermomechanical effect

Nontraditional energy-assisted mechanical machining of difficult-to-cut materials and components in aerospace community:a comparative analysis

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International Journal of Extreme Manufacturing 2024年第2期6卷 190-271页

作者： Guolong Zhao Biao Zhao wenfeng Ding Lianjia Xin Zhiwen Nian Jianhao Peng Ning He Jiuhua xu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016People’s Republic of China

The aerospace community widely uses difficult-to-cut materials,such as titanium alloys,high-temperature alloys,metal/ceramic/polymer matrix composites,hard and brittle materials,and geometrically complex components,such as thin-walled structures,microchannels,and complex *** machining is the main material removal process for the vast majority of aerospace ***,many problems exist,including severe and rapid tool wear,low machining efficiency,and poor surface *** energy-assisted mechanical machining is a hybrid process that uses nontraditional energies(vibration,laser,electricity,etc)to improve the machinability of local materials and decrease the burden of mechanical *** provides a feasible and promising method to improve the material removal rate and surface quality,reduce process forces,and prolong tool ***,systematic reviews of this technology are lacking with respect to the current research status and development *** paper reviews the recent progress in the nontraditional energy-assisted mechanical machining of difficult-to-cut materials and components in the aerospace *** addition,this paper focuses on the processing principles,material responses under nontraditional energy,resultant forces and temperatures,material removal mechanisms,and applications of these processes,including vibration-,laser-,electric-,magnetic-,chemical-,advanced coolant-,and hybrid nontraditional energy-assisted mechanical ***,a comprehensive summary of the principles,advantages,and limitations of each hybrid process is provided,and future perspectives on forward design,device development,and sustainability of nontraditional energy-assisted mechanical machining processes are discussed.

关键词： difficult-to-cut materials geometrically complex components nontraditional energy mechanical machining aerospace community

Carbon uptake by cement in china:Estimation and contribution to carbon neutrality goals

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Science china Earth Sciences 2024年第6期67卷 2056-2067页

作者： Mingjing MA Zi HUANG Jiaoyue WANG Le NIU wenfeng ZHANG Xiaowei xu Fengming XI Zhu LIU Institute of Applied Ecology Chinese Academy of SciencesShenyang 110016China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Department of Earth System Science Tsinghua UniversityBeijing 100084China Department of Engineering Science University of OxfordOxfordOX13UK

Cement is a widely used construction material *** manufacturing contributes to anthropogenic CO_(2)emissions ***,its alkaline compounds can absorb CO_(2)from the surrounding environment and engage in a carbonation reaction,thereby functioning as a carbon *** a major cement producer and consumer,china has an important responsibility to rigorously investigate and accurately account for cement carbon *** study presents a comprehensive analytical model of cement carbon uptake from china,revealing a substantial increase in carbon uptake from 1930 to 2021,peaking at 426.77 Mt CO_(2)(95% Confidence Interval:317.67-874.33 Mt CO_(2))in *** uptake accounts for 8.10% to 45.40% of china’s annual land sink and 2.51% to 4.54% of the global land *** cumulative carbon uptake by cement is approximately 7.06 Gt CO_(2)(95%CI:5.22–9.44 Gt CO_(2))during this period,offsetting 50.7% of the total emissions(13.91 Gt CO_(2),95%CI:12.44–17.00 Gt CO_(2))from the cement ***,cement mortar contributed to most absorption(65.64%).From a life cycle perspective,the service stage of cement materials is the period where the largest CO_(2)sink is formed,accounting for 90.03% of the ***,the potential for carbon sequestration in cement materials and their waste is ***,the model improves the accuracy of cement carbon accounting,supporting both china and global carbon neutrality ***,it is crucial for china to achieve its carbon neutrality goals sooner by prioritizing the environmental benefits of cement materials and wastes,and accelerating the development and commercialization of CO_(2)sequestration technologies for cement and its by-products.

关键词： Cement Carbon uptake Life cycle assessment Carbon emission reduction Carbon neutrality

Towards Sustainable Grinding of Difficult-to-Cut Alloys-A Holistic Review and Trends

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 1-28页

作者： Ning Qian Jiajia Chen Aqib Mashood Khan Biao Zhao Yurong Chen wenfeng Ding Yucan Fu Jiuhua xu Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037China JITRI Institute of Precision Manufacturing Nanjing 211805China

Grinding,a critical precision machining process for difficult-to-cut alloys,has undergone continual technological advancements to improve machining ***,the sustainability of this process is gaining heightened attention due to significant challenges associated with the substantial specific grinding energy and the extensive heat generated when working with difficult-to-cut alloys,renowned for their exceptional physical and mechanical *** response to these challenges,the widespread application of massive coolant in manufacturing industries to dissipate grinding heat has led to complex post-cleaning and disposal ***,in turn,has resulted in issues such as large energy consumption,a considerable carbon footprint,and concerns related to worker health and safety,which have become the main factors that restrict the development of grinding *** paper provides a holistic review of sustainability in grinding difficult-to-cut alloys,encompassing current trends and future *** examination extends to developing grinding technologies explicitly tailored for these alloys,comprehensively evaluating their sustainability ***,the exploration delves into innovative sustainable technologies,such as heat pipe/oscillating heat pipe grinding wheels,minimum quantity lubrication,cryogenic cooling,and *** groundbreaking technologies aim to reduce dependence on hazardous coolants,minimizing energy and resource consumption and carbon emissions associated with coolant-related or subsequent disposal *** essence of these technologies lies in their potential to revolutionize traditional grinding practices,presenting environmentally friendly ***,future development trends and research directions are put forward to pursue the current limitation of sustainable grinding for difficult-to-cut *** paper can guide future research and development efforts toward more environmentally friendly

关键词： Grinding Sustainability Cooling Energy consumption Carbon footprint Difficult-to-cut alloys

Promoted catalytic performance of Ag-Mn bimetal catalysts synthesized through reduction route

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Journal of Environmental Sciences 2024年第3期137卷 358-369页

作者： Wenkai Hu Tao Guo Kaiyao Ma xu Li Wangting Luo Mingzhi Wu Hao Guo Yaxin Zhang wenfeng Shangguan School of Chemical Engineering and Technology Xinjiang UniversityUrumchi 830017China Research Center for Combustion and Environmental Technology Shanghai Jiao Tong UniversityShanghai 200240China

VOCs can exert great harm to both human and environment,and catalytic oxidation is believed to be an effective technique to eliminate these *** this paper,Ag-Mn bimetal catalysts with 10 wt.%of silver were synthesized using doping,impregnation,and reduction methods respectively,and then they were applied to the catalytic oxidation of *** series of characterizations it showed that the loading of silver using reduction method significantly resulted in improved physico-chemical properties of manganese oxides,such as larger surface area and pore volume,higher proportion of surface Mn~(3+)and Mn~(4+),stronger reducibility and more active of surface oxygen species,which were all beneficial to its catalytic *** a result,the Ag-Mn catalysts synthesized by reduction method showed a lower T_(90)value(equals to the temperature at which 90%of initial benzene was removed)of 203℃.Besides,both the used and fresh Ag-Mn catalysts synthesized by reduction method showed preferable stability in this research.

关键词： Ag-Mn Benzene oxidation Catalytic performance Reduction route

Soil pH and phosphorus drive the canonical nitrifiers and comammox Nitrospira communities in citrus orchards with different cultivation ages

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Soil Ecology Letters 2024年第2期6卷 111-124页

作者： Haiyang Liu Zhikang Tao Hongen Liu Wei xu Yuanyi Qin Zhaojun Nie wenfeng Tan College of Resources and Environmental Sciences Henan Agricultural UniversityZhengzhou450002China Key Laboratory of Horticultural Plant Biology The Ministry of EducationCollege of Resources and EnvironmentHuazhong Agricultural UniversityWuhan430070China Guizhou Rice Research Institute Guizhou Academy of Agricultural SciencesGuiyang550006China

Comammox Nitrospira clade A and B showed contrasting responses to citrus planting.54d9-like AOA and Nitrobacter-NOB dominated in the 5Y and 10Y ***-like AOA and Nitrospira-like NOB dominated in the 20Y and 30Y *** pH ... 详细信息

关键词： AOB AOA comammox Nitrospira NOB soil pH phosphorus content

Dynamic Relationship Between Human Microbiota and Host Factors

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Infectious Microbes & Diseases 2024年第3期6卷 106-107页

作者： Qi Zheng Yuetong Li wenfeng Zhu Xiang xu Baozhen Luo Guoping Sheng Lanjuan Li State Key Laboratory for Diagnosis and Treatment of Infectious Diseases National Clinical Research Center for Infectious DiseasesNational Medical Center for Infectious DiseasesCollaborative Innovation Center for Diagnosis and Treatment of Infectious DiseasesThe First Affiliated HospitalZhejiang University School of MedicineHangzhouChina Zhejiang Chinese Medical university HangzhouChina Key Laboratory of Artificial Organs and Computational Medicine in Zhejiang Province Shulan(Hangzhou)Hospital Affiliated to Shulan International Medical CollegeZhejiang Shuren UniversityHangzhouChina.

There have been considerable investigations into the composition of the microbiota inhabiting various anatomical sites of the human body,including but not limited to the gut and ***,the distribution of the microbiota composition and functionality across anatomical sites within the same individual are not yetwell-established,in particular in relation with host health and disease.

关键词： microbiota dynamic equilibrium host

Riverine sulfate sources and behaviors in arid environment,Northwest china:Constraints from sulfur and oxygen isotopes

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Journal of Environmental Sciences 2024年第3期137卷 716-731页

作者： Yifu xu Wenjing Liu Bing xu Zhifang xu Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China university of Chinese Academy of Sciences Beijing 100049China

The fate of riverine sulfate ion (SO_(4)^(2-)) and its environmental effects in arid environment are difficult to evaluate due to its complicated sources and strongly coupled behaviors with water cycle which is significantly modified by *** understand the sulfur cycle in aquatic systems in arid environment,the chemical and sulfur and oxygen isotopic compositions (δ^(34)S_(SO4)and δ^(18)O_(SO4)) of major rivers around the Badain Jaran Desert,northwestern china,were *** rivers had averaged SO_(4)^(2-)content at 1336μmol/L,over 10times higher than the global *** δ^(34)S_(SO4)and δ^(18)O_(SO4)values ranged from-5.3‰to+11.8‰and+1.6‰to+12.8‰,*** end-member analysis and the inverse model showed that riverine sulfate was mainly derived from evaporites dissolution (0-87%),sulfide oxidation (13%-100%) and precipitation (0-33%),indicating heterogeneity in sulfur sources and behaviors along the river drainage with the lithology variations and climate *** isotopic tools combining with hydro-chemistry compositions could be applied to reveal sulfur cycle in arid *** on the calculation,sulfide oxidation plays the primary role in the headwater and upstream in the Qilian-Mountains area,where sulfide is widely *** the proportion of evaporites dissolution contributing to riverine sulfate is much higher in downstream in a drier ***,less precipitation and higher temperature can lead to more intensive evaporation,affecting the process of sulfide oxidation and enhancing the rates of evaporites dissolution and sulfate precipitation in the basin.

关键词： Sulfur and oxygen isotopes Source apportionment Inverse model Arid environment Inland rivers Northwestern china