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A discussion of fatigue properties of notched specimens subjected to prestressing treatment machined from FGH4097

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Chinese Journal of Aeronautics 2024年第4期37卷 508-523页

作者： Rongxi SHI Dasheng WEI le HAN Shun YANG School of Energy and Power Engineering Beihang UniversityBeijing 100191China Jiangxi Research Institute Beihang UniversityNanchang 330096China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

Experimental and numerical investigations were performed to reveal the effect of prestress on the fatigue properties of FGH4097 so as to quantitatively evaluate the overspeed benefit of the disc of aeroengine. A corresponding experiment was performed to examine the effect of prestress on the fatigue life of FGH97. A complete model describing the fatigue properties of the prestressed notch specimen was proposed. After the modification of mean stress, stress gradient and prestressing treatment, the model is finally verified by fatigue test of presstressed notch specimens machined from FGH4097 with satisfactory accuracy and good engineering applicability. The new model highlights that for the variable fatigue loads, the introduction of appropriate prestress is expected to benefit to the notch specimens and certainly to the disc of aeroengine regards of their fatigue properties. Both the calculation method of fatigue life parameters and the prestress correction model are proved to have good prediction accuracy.

关键词： Turbine blisk Overspeed test Prestress Fatigue life prediction FGH4097

Your personal choices in transportation and food are important for lowering carbon emissions

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Frontiers of Environmental Science & Engineering 2024年第6期18卷 27-32页

作者： Bruce Logan Fang Zhang Wulin Yang le Shi Institute of Energy and the Environment The Pennsylvania State UniversityUniversity ParkPA 16802USA School of Environment Tsinghua UniversityBeijing 100084China College of Environmental Sciences and Engineering Peking UniversityBeijing 100871China College of Environmental and Resource Sciences Zhejiang UniversityHangzhou 310058China

There is a global need to reduce greenhouse gas emissions to limit the extent of climate change.A better understanding of how our own activities and lifestyle influence our energy use and carbon emissions can help us enable changes in activities that can lead to reductions in carbon *** we discuss an approach based on examining carbon emissions from the perspective of the unit C,where 1 C is the CO_(2)from food a person would on average eat every *** approach shows that total CO_(2)emissions in China,normalized by the population,is 22.5 C while carbon emissions for a person in the US is 43.9 C.A better appreciation of our own energy use can be obtained by calculating carbon emissions from our own activities in units of C,for example for driving a car gasoline or electric vehicle a certain number of kilometers,using electricity for our homes,and eating different *** this information,we can see how our carbon emissions compare to national averages in different countries and make decisions that could lower our personal CO_(2)emissions.

关键词： Carbon dioxide Climate change Daily energy Greenhouse gas

Enabling heterogeneous catalysis to achieve carbon neutrality: Directional catalytic conversion of CO_(2) into carboxylic acids

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Carbon Energy 2024年第3期6卷 1-35页

作者： Xiaofei Zhang Wenhuan Huang le Yu Max García-Melchor Dingsheng wang Linjie Zhi Huabin Zhang KAUST Catalysis Center(KCC) King Abdullah University of Science and Technology(KAUST)ThuwalSaudi Arabia Key Laboratory of Chemical Additives for China National Light Industry College of Chemistry and Chemical EngineeringShaanxi University of Science and TechnologyXi'anChina State Key Lab of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijingChina School of Chemistry CRANN and AMBERResearch CentresTrinity College DublinCollege GreenDublinIreland Department of Chemistry Tsinghua UniversityBeijingChina Advanced Chemical Engineering and Energy Materials Research Center China University of Petroleum(East China)QingdaoChina

The increase in anthropogenic carbon dioxide(CO_(2))emissions has exacerbated the deterioration of the global environment,which should be controlled to achieve carbon *** to the core goal of achieving carbon neutrality is the utilization of CO_(2) under economic and sustainable ***,the strong need for carbon neutrality has led to a proliferation of studies on the direct conversion of CO_(2) into carboxylic acids,which can effectively alleviate CO_(2) emissions and create high-value *** purpose of this review is to present the application prospects of carboxylic acids and the basic principles of CO_(2) conversion into carboxylic acids through photo-,electric-,and thermal *** attention is focused on the regulation strategy of the activity of abundant catalysts at the molecular level,inspiring the preparation of high-performance *** addition,theoretical calculations,advanced technologies,and numerous typical examples are introduced to elaborate on the corresponding process and influencing factors of catalytic ***,challenges and prospects are provided for the future development of this *** is hoped that this review will contribute to a deeper understanding of the conversion of CO_(2) into carboxylic acids and inspire more innovative breakthroughs.

关键词： carbon neutrality carboxylic acids CO_(2)conversion heterogeneous catalyst in situ technology

Fabrication of Cu_2O@Cu_2O core-shell nanoparticles and conversion to Cu_2O@Cu core-shell nanoparticles in solution

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Transactions of Nonferrous Metals Society of China 2015年第11期25卷 3643-3650页

作者：杨爱玲李顺嫔王玉金王乐乐包西昌杨仁强中国海洋大学物理系青岛266100 中国科学院生物能源与过程研究所青岛266101

Cu2O@Cu2O core-shell nanoparticles (NPs) were prepared by using solution phase strategy. It was found that Cu2O@Cu2O NPs were easily converted to Cu2O@Cu NPs with the help of polyvinylpyrrolidine (PVP) and excessive ascorbic acid (AA) in air at room temperature, which was an interesting phenomenon. The features of the two kinds of NPs were characterized by XRD, TEM and extinction spectra. Cu2O@Cu NPs with different shell thicknesses showed wide tunable optical properties for the localized surface plasmon (LSP) in metallic Cu. But Cu2O@Cu2O NPs did not indicate this feature. FTIR results reveal that Cu+ ions on the surface of Cu2O shell coordinate with N and O atoms in PVP and are further reduced to metallic Cu by excessive AA and then form a nucleation site on the surface of Cu2O nanocrystalline. PVP binds onto different sites to proceed with the reduction utill all the Cu sources in Cu2O shell are completely assumed.

关键词： Cu2O@Cu2O core-shell nanoparticles Cu2O@Cu core-shell nanoparticles solution phase strategy reducing agent tunable optical properties polyvinylpyrrolidine

Characteristics and quality of clinical practice guidelines for diabetic kidney disease: a systematic review

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Journal of Traditional Chinese Medicine 2024年第3期44卷 609-619页

作者： wang Yuhuang ZHANG le ZHANG Zhengshan YAO Zhi LI Xiyao SUN Luying LIAO Xing Department of Nephropathy and Endocrine Dongzhimen HospitalBeijing University of Chinese Medicine Centre for Evidence-Based Chinese Medicine Institute of Basic Research in Clinical MedicineChina Academy of Chinese Medical Sciences Department of Endocrine One Zone Fangshan HospitalBeijing University of Chinese Medicine

OBJECTIVE: To assess the quality of Clinical practice guidelines(CPGs) in the context of diabetic kidney disease(DKD) and determine whether any factors affect the quality. METHODS: We searched eight databases along with five international and national organizations to develop or archive guidelines from their inception to July 2023, with an additional search of ***. And the authoritative organizations related to nephrology. CPGs and consensus statements created using direct differential diagnosis or therapy for DKD were included without language restrictions. Their quality was evaluated by four reviewers using the Appraisal of Guidelines for Research and Evaluation Ⅱ(AGREE Ⅱ) instrument. Along with the item and domain scores, the guideline was also allocated an overall quality score, which ranged from 1(lowest possible quality) to 7(highest possible quality). Moreover, an overall recommendation for use was also assigned(“recommended”, “recommended with modifications” or “not recommended”). RESULTS: A total of 16 CPGs were included, of which 14 were from Asia and the remaining two from Europe. These two CPGs were updated in the third version. Six CPGs were recommended for use because their primary domains scored in the medium or high category. Furthermore, five CPGs were recommended with modifications as the stakeholder involvement, applicability, and editorial independence domains were evaluated as low categories. In all domains, the lowest average score was for rigour of development(33%), followed by application(36%), and stakeholder involvement(51%). The highest average score was for scope and purpose(79%), followed by clarity of presentation(75%). None of the CPGs considered the patient's viewpoint, and six of 16 CPGs did not use any grading system to translate the evidence into recommendations. Additionally, only three of 16 CPGs shared search strategy, and eight of 16 CPGs did not declare a funding source. CONCLUSIONS: According to the AGREE II evaluation

关键词： appraisal of guidelines for research and evaluation II diabetic nephropathies practice guideline quality assessment systematic review

Study on the green extraction of corncob xylan by deep eutectic solvent

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Grain & Oil Science and Technology 2024年第1期7卷 50-59页

作者： Bingyu Jiao le wang Haitao Gui Zifu Ni Rong Du Yuansen Hu School of Biological Engineering National Engineering Research Center of Wheat and Corn Further ProcessingZhengzhou 450001China

Corn as one of the world's major food crops,its by-product corn cob is also rich in ***,the unreasonable utilization of corn cob often causes the environmental pollution,waste of resources and other *** one of the most abundant polymers in nature,xylan is widely used in food,medicine,materials and other *** cob is rich in xylan,which is an ideal raw material for extracting ***,the intractable lignin is covalently linked to xylan,which increases the difficulty of xylan *** has been reported that the deep eutectic solvent(DES)could preferentially dissolve lignin in biomass,thereby dissolving the ***,the xylan in the extract was separated by ethanol precipitation *** xylan precipitate was obtained after centrifugation,while the supernatant was *** components of the supernatant after ethanol precipitation were separated by the rotary *** ethanol,water and DES were collected for the subsequent extraction of corn cob *** this study,a novel way was provided for the green production of corn cob *** DES was used to extract xylan from corn cob which was used as the raw *** effects of solid-liquid ratio,reaction time,reaction temperature and water content of DES on the extraction rate of corn cob xylan were investigated by the single factor ***,the orthogonal test was designed to optimize the xylan extraction *** structure of corn cob xylan was analyzed and *** results showed that the optimum extraction conditions of corn cob xylan were as follows:the ratio of corn cob to DES was 1:15(g:mL),the extraction time was 3 h,the extraction temperature was 60℃,and the water content of DES was 70%.Under these conditions,the extraction rate of xylan was 16.46%.The extracted corn cob xylan was distinctive triple helix of polysaccharide,which was similar to the structure of commercially available *** was effectively and workably extracted from corn

关键词： Corncob Deep eutectic solvent Xylan Process optimization Extraction

Top priority current path between SiC particles during ultra-high temperature flash sintering: Presence of PyC “bridges”

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Journal of Advanced Ceramics 2024年第2期13卷 255-262页

作者： le Lu Tianlong Liu Zhaofeng Chen Fei wang Mengmeng Yang Qiong Wu Lixia Yang Huanyong Li International Laboratory for Insulation and Energy Efficiency Materials College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing 211106China State Key Laboratory of Solidification Processing School of Materials and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

Flash sintering(FS)is a novel technique for rapidly densifying silicon carbide(SiC)*** work achieved a rapid sintering of SiC ceramics by the utilization of ultra-high temperature flash sintering within 60 *** carbon(PyC)“bridges”were constructed between SiC particles through the carbonisation of phenolic resin,providing a large number of current *** incubation time of the flash sintering process was significantly reduced,and the sintering difference between the centre and the edge regions of the ceramics was minimized,with an average particle size of the centre region and edge region being 12.31 and 9.02μm,*** results showed that the porosity of the SiC ceramics after the flash sintering was reduced to 14.79% with PyC“bridges”introduced,and the Vickers hardness reached 19.62 ***“bridges”gradually evolved from amorphous eddy current carbon to oriented graphite carbon,indicating that the ultra-high temperature environment in which the sample was located during the flash sintering was successfully ***-high temperature flash sintering of SiC is expected to be applied to the local repair of matrix damage in SiC ceramic matrix composites.

关键词： silicon carbide(SiC) flash sintering(FS) pyrolytic carbon(PyC)"bridges" current path instantaneous

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

Sensitivity impacts owing to the variations in the type of zero-range pairing forces on the fission properties using the density functional theory

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Nuclear Science and Techniques 2024年第3期35卷 198-207页

作者： Yang Su Ze-Yu Li Li-le Liu Guo-Xiang Dong Xiao-Bao wang Yong-Jing Chen China Nuclear Data Center China Institute of Atomic EnergyBeijing 102413China School of Science Huzhou UniversityHuzhou 313000China

Using the Skyrme density functional theory,potential energy surfaces of^(240)Pu with constraints on the axial quadrupole and octupole deformations(q_(20)and q_(30))were *** volume-like and surface-like pairing forces,as well as a combination of these two forces,were used for the Hartree–Fock–Bogoliubov *** in the least-energy fission path,fission barrier,pairing energy,total kinetic energy,scission line,and mass distribution of the fission fragments based on the different forms of the pairing forces were analyzed and *** fission dynamics were studied based on the timedependent generator coordinate method plus the Gaussian overlap *** results demonstrated a sensitivity of the mass and charge distributions of the fission fragments on the form of the pairing *** on the investigation of the neutron-induced fission of^(239)Pu,among the volume,mixed,and surface pairing forces,the mixed pairing force presented a good reproduction of the experimental data.

关键词： Nuclear fission Density functional theory Pairing force Potential energy surfaces Fission fragment distribution