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Superior compound coatings prepared by low-temperature vanadium-nitrocarburizing duplex treatment

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Rare Metals 2024年第4期43卷 1828-1835页

作者： Gen jin Fang-Fang Xu Xun-Xun hu yue Xu School of Chemistry Beihang UniversityBeijing100191China Guobiao(Beijing)Testing and Certification Co. LtdBeijing100088China School of Materials Science and Engineering Beihang UniversityBeijing100191China

Superior compound coatings were prepared on CK45 steel surface by vanadium-nitrocarburizing duplex treatment in low-temperature salt *** this study,the microhardness,the phase constitution and the compositional distribution in the coatings prepared under different conditions were systematically *** results indicated that the reactions among activated vanadium,carbon and nitrogen atoms occurred on the steel surface,leading to the formation of compound coatings composed of outermost and compound *** mechanism for the formation of compound layer as well as the growth kinetics of the layer was also *** the duplex treatment,the wear and corrosion resistances of steel surface were significantly *** was found that the growth kinetics of compound layer obeyed the parabolic law,with the activation energy of 122.82 kJ·moL^(-1).

关键词： Vanadium-nitrocarburizing duplex treatment Compound coatings Microstructure Formation mechanism Growth kinetics

Effect of ni content on the wear behavior of Al-Si-Cu-Mg-ni/SiC particles composites

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 374-383页

作者： yanyu Liu Lina Jia Wenbo Wang Zuheng jin hu Zhang School of Materials Science and Engineering Beihang UniversityBeijing 100191China ningbo Institute of Technology Beihang UniversityNingbo 315100China Qingdao Research Institute of Beihang University Qingdao 266000China Research Institute for Frontier Science Beihang UniversityBeijing 100191China

In recent years,the addition of ni has been widely acknowledged to be capable of enhancing the mechanical properties of Al-Si ***,the effect of ni on the wear behaviors of Al-Si alloys and Al matrix composites,particularly at elevated temperat-ures,remains an understudied *** this study,Al-Si-Cu-Mg-ni/20wt%SiC particles(SiCp)composites with varying ni contents were prepared by using a semisolid stir casting *** effect of ni content on the dry sliding wear behavior of the prepared compos-ites was investigated through sliding tests at 25 and 350℃.Results indicated that theθ-Al_(2)Cu phase gradually diminished and eventually disappeared as the ni content increased from 0wt%to 3wt%.This change was accompanied by the formation and increase inδ-Al_(3)Cuni andε-Al_(3)ni phases in *** hardness and ultimate tensile strength of the as-cast composites improved,and the wear rates of the composites decreased from 5.29×10^(−4)to 1.94×10^(−4)mm^(3)/(n∙m)at 25℃and from 20.2×10^(−4)to 7×10^(−4)mm^(3)/(n∙m)at 350℃with the increase in ni content from 0wt%to 2wt%.The enhancement in performance was due to the presence of strengthening network structures and additional ni-containing phases in the ***,the wear rate of the 3ni composite was approximately two times higher than that of the 2ni composite due to the fracture and debonding of theε-Al_(3)ni *** wear,delamination wear,and oxidation wear were the predominant wear mechanisms of the investigated composites at 25℃,whereas delamination wear and oxid-ation wear were dominant during sliding at 350℃.

关键词： Al matrix composite microstructure sliding test high temperature wear mechanism

Chemico-biological conversion of carbon dioxide

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Journal of Energy Chemistry 2024年第2期89卷 371-387,I0009页

作者： Liangwei hu Junzhu yang Qi Xia jin Zhang Hongxin Zhao yuan Lu Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation College of Life Sciences and MedicineZhejiang Sci-Tech UniversityHangzhou 310018ZhejiangChina Key Laboratory of Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084China Department of Chemical Engineering Tsinghua UniversityBeijing 100084China College of Biological and Chemical Engineering Jiaxing UniversityJiaxing 314000ZhejiangChina

The unabated carbon dioxide(CO_(2))emission into the atmosphere has exacerbated global climate change,resulting in extreme weather events,biodiversity loss,and an intensified greenhouse *** address these challenges and work toward carbon(C)neutrality and reduced CO_(2)emissions,the capture and utilization of CO_(2)have become imperative in both scientific research and *** cutting-edge approach to achieving efficient catalytic performance involves integrating green bioconversion and chemical *** innovative strategy offers several advantages,including environmental friendliness,high efficiency,and *** study provides a comprehensive review of existing technical routes for carbon sequestration(CS)and introduces two novel CS pathways:the electrochemicalbiological hybrid and artificial photosynthesis *** also thoroughly examines the synthesis of valuable Cnproducts from the two CS systems employing different catalysts and *** both systems heavily rely on electron transfer,direct and mediated electron transfer has been discussed and summarized in ***,this study explores the conditions suitable for different catalysts and assesses the strengths and weaknesses of *** also explored the biocompatibility of the electrode materials and developed novel *** materials were specifically engineered to combine with enzymes or microbial cells to solve the biocompatibility problem,while improving the electron transfer efficiency of ***,this review summarizes the relevant systems developed in recent years for manufacturing different products,along with their respective production efficiencies,providing a solid database for development in this *** novel chemical-biological combination proposed herein holds great promise for the future conversion of CO_(2)into advanced organic ***,it offers exciting prospects for utilizing CO_(2)in synthesizing

关键词： Carbon dioxide Bioelectric synthesis Artificial photosynthesis Synthetic product

Assessment of International GnSS Service Global Ionosphere Map products over China region based on measurements from the Crustal Movement Observation network of China

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Earth and Planetary Physics 2024年第2期8卷 400-407页

作者： jin hu HaiBing Ruan FuQing huang Shengyang Gu XianKang Dou Institute of Space Weather Nanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Space Weather Chinese Academy of Sciences(CAS)Beijing 100190China School of Electronic Information Wuhan UniversityWuhan 430072China Wuxi Research Institute Nanjing University of Information Science and TechnologyWuxi Jiangsu 214000China CAS Key Laboratory of Geospace Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China

The global ionosphere maps(GIM)provided by the International GnSS Service(IGS)are extensively utilized for ionospheric morphology monitoring,scientific research,and practical *** the credibility of GIM products in data-sparse regions is of paramount *** this study,measurements from the Crustal Movement Observation network of China(CMOnOC)are leveraged to evaluate the suitability of IGS-GIM products over China region in *** indices of mean error(ME),root mean square error(RMSE),and normalized RMSE(nRMSE)are then utilized to quantify the accuracy of IGS-GIM *** revealed distinct local time and latitudinal dependencies in IGS-GIM errors,with substantially high errors at nighttime(nRMSE:39%)and above 40°latitude(nRMSE:49%).Seasonal differences also emerged,with larger equinoctial deviations(nRMSE:33.5%)compared with summer(20%).A preliminary analysis implied that the irregular assimilation of sparse IGS observations,compounded by China’s distinct geomagnetic topology,may manifest as error *** results suggest that modeling based solely on IGS-GIM observations engenders inadequate representations across China and that a thorough examination would proffer the necessary foundation for advancing regional total electron content(TEC)constructions.

关键词： International GnSS Service(IGS)Global Ionosphere Maps(GIM) Crustal Movement Observation network of China(CMOnOC) total electron content(TEC) data assessment

Buried interface management via bifunctional nH_(4)BF_(4)towards efficient CsPbI_(2)Br solar cells with a V_(oc)over 1.4 V

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Journal of Energy Chemistry 2024年第2期89卷 364-370,I0009页

作者： Fazheng Qiu Ming-hua Li jinpeng Wu jin-Song hu School of Materials Science and Engineering NingboTech UniversityNingbo 315100ZhejiangChina Beijing national Laboratory for Molecular Sciences(BnLMS) Institute of ChemistryChinese Academy of SciencesBeijing 100190China College of Chemical Engineering Beijing Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China

CsPbI_(2)Br perovskite solar cells(PSCs)have drawn tremendous attention due to their suitable bandgap,excellent photothermal stability,and great potential as an ideal candidate for top cells in tandem solar ***,the abundant defects at the buried interface and perovskite layer induce severe charge recombination,resulting in the open-circuit voltage(V_(oc))output and stability much lower than ***,a novel buried interface management strategy is developed to regulate interfacial carrier dynamics and CsPbI_(2)Br defects by introducing ammonium tetrafluoroborate(nH_(4)BF_(4)),thereby resulting in both high CsPbI_(2)Br crystallization and minimized interfacial energy ***,nH_(4)^(+)ions could preferentially heal hydroxyl groups on the SnO_(2)surface and balance energy level alignment between SnO_(2)and CsPbI_(2)Br,enhancing charge transport efficiency,while BF_(4)^(-)anions as a quasi-halogen regulate crystal growth of CsPbI_(2)Br,thus reducing perovskite ***,it is proved that eliminating hydroxyl groups at the buried interface enhances the iodide migration activation energy of CsPbI_(2)Br for strengthening the phase *** a result,the optimized CsPbI_(2)Br PSCs realize a remarkable efficiency of 17.09%and an ultrahigh V_(oc)output of 1.43 V,which is one of the highest values for CsPbI_(2)Br PSCs.

关键词： Inorganic perovskite Buried interface Defect Stability Open-circuit voltage loss

Hot Deformation Behavior and Microstructures Evolution of GnP-Reinforced Fine-Grained Mg Composites

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 407-424页

作者： Hengrui hu Jiayu Qin yunpeng Zhu jinhui Wang Xiaoqiang Li Peipeng jin Qinghai Provincial Key Laboratory of new Light Alloys Qinghai UniversityXining 810016China Qinghai Provincial Engineering Research Center of High Performance Light Metal Alloys and Forming Qinghai UniversityXining 810016China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China School of Material Science and Engineering Lanzhou University of TechnologyLanzhou 730050China

Graphene nanoplates(GnPs)-reinforced magnesium matrix composites have been attracted great ***,knowledge is lack for the hot deformation behavior of GnP-reinforced magnesium(GnPs/Mg)*** this study,the fine-grained GnPs/Mg composite was fabricated by powder metallurgy process followed by *** hot deformation behavior,microstructure evolution and dynamic recrystallization(DRX)mechanism of fine-grained GnPs/Mg composite were investigated by hot compression test and electron back-scatter diffraction(EBSD).The hot compression tests of the composite were conducted at temperatures between 423 and 573 K with the strain rates from 0.001 to 1 s^(-1).The strain compensated power law equation was established to describe the hot deformation behavior of the *** stress exponent and activation energy of the composite are 7.76 and 83.23 kJ/mol,respectively,suggesting that the deformation mechanism is grain boundary slip controlled dislocation climb *** abnormally high stress exponent and activation energy are unattainable in the composite due to the fine grain size of the composites and the absence of Zener pinning and Orowan effects of GnPs *** grain size increases with the decrease in Zener-Hollomn(Z)parameter,which can be well fitted by power-law *** the increase in grain size and decrease in Z parameter,the geometrically necessary dislocation density decreases,which shows the approximately power-law relationship.A random and weak texture was formed after hot *** discontinuous dynamic recrystallization and continuous dynamic recrystallization mechanism dominated the DRX behavior at 473 K/0.001 s^(-1) and 573 K/0.001 s^(-1),respectively.

关键词： GnPs Mg composite Hot deformation behavior Constitutive equations Microstructure evolution Dynamic recrystallization

Effect of Low-Temperature Thermal Oxidation on the Capillary Performance of Sintered Copper Powder Wicks

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Journal of Thermal Science 2024年第1期33卷 29-40页

作者： Zhu Minghan FAnG Runquan hu yanxin ZHAnG Jiangyun SHAO Dan huAnG jin School of Material and Energy Guangdong University of TechnologyGuangzhou 510006China School of Electric Power Engineering Guangdong Polytechnic of Water Resources and Electric EngineeringGuangzhou 510006China Research into Artifacts Guangdong Key Laboratory of Battery SafetyGuangzhou Institute of Energy testingGuangzhou 511447China

In this study,a composite powder capillary wick is prepared,manufactured by sintering copper powder and surface treated by low-temperature thermal *** is used to improve the performance of the capillary *** forced flow method and infrared imaging method are used to test the permeability and capillary performance of the *** effects of different oxidation temperatures on the performance of capillary wick are *** experimental results show that the wetting performance of the oxidized samples is significantly *** the increase of oxidation temperature,the permeability *** capillary height and velocity of the thermally oxidized samples are significantly higher than those of the untreated capillary ***,the oxidation temperature needs to be adjusted to obtain the best capillary *** highest capillary performance is found at oxidation temperature of 300℃,with an increase of 46% compared to the untreated *** with other composite wicks show that the sample with an oxidation temperature of 300℃ has competitive capillary performance,making it a favorable alternative to two-phase heat transfer *** study shows that combining low-temperature thermal oxidation technology with powder sintering is a convenient and effective method to improve the capillary performance of powder wicks.

关键词： low-temperature thermal oxidation capillary performance copper powder permeability

Disease Burden and Costs Associated with Multiple Sclerosis in China:A Cross-sectional Analysis of nationwide Survey Data

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neuroscience Bulletin 2024年第4期40卷 533-538页

作者： yusheng Jia Xuanqi Qiao jin Zhao Hainan Li Shanlian hu Min hu Department of Health Economics School of Public HealthFudan UniversityShanghai200032China national Health Commission Key Laboratory of Health Technology Assessment Fudan UniversityShanghai200032China

DearEditors,Multiple sclerosis(MS)is a chronic,autoimmune neurological disorder characterized by inflammatory demyelination of the central nervous system;it is associated with reduced mobility,cognitive impairment,and numerous comorbidities[1].Global MS incidence(2.1 per 100,000 person-years)and prevalence(30.1 per 100,000)have increased in recent years,and its prevalence is notably higher in Western countries,ranging from~30 to 200 cases per 100,000[2].In China,recent epidemiological research has shown that the crude prevalence was 2.44 per 100,000 in 2016[3],and the age-and sex-adjusted incidence was 0.235 per 100,000 person-years[4].Despite the relatively low prevalence compared with the global average,China has extensively addressed the well-being of over 30,000 MS patients,enrolling MS in China's First national List of Rare Diseases in 2018.

关键词： prevalence impairment autoimmune

A Cnn-SVR model for nO_(2)profile prediction based on MAX-DOAS observations:The influence of Chinese new year overlapping the 2020 COVID-19 lockdown on vertical distributions of tropospheric nO_(2)in nanjing,China

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Journal of Environmental Sciences 2024年第7期141卷 151-165页

作者： Xin Tian Zijie Wang Pinhua Xie jin Xu Ang Li yifeng Pan Feng hu Zhaokun hu Mingsheng Chen Jiangyi Zheng Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China Key laboratory of Environmental Optical and Technology Anhui Institute of optics and Fine MechanicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China School of Environmental Science and Optoelectronic Technology University of Science and Technology of ChinaHefei 230026China

In this study,a hybrid model,the convolutional neural network-support vector regression model,was adopted to achieve prediction of the nO_(2)profile in nanjing from January 2019to March *** the sudden decline in nO_(2)in February 2020,the contribution of the Coronavirus Disease-19(COVID-19)lockdown,Chinese new year(Cny),and meteorologi cal conditions to the reduction of nO_(2)was ***_(2)vertical column densities(VCDs) from January to March 2020 decreased by 59.05%and 32.81%,relative to the same period in 2019 and 2021,*** the period of 2020 COVID-19,the average nO_(2)VCDs were 50.50%and 29.96%lower than those during the pre-lockdown and post-lockdown pe riods,*** nO_(2)volume mixing ratios(VMRs)during the 2020 COVID-19 lock down significantly decreased below 400 *** nO_(2)VMRs under the different wind fields were significantly lower during the lockdown period than during the pre-lockdown period This phenomenon could be attributed to the 2020 COVID-19 *** nO_(2)VMRs be fore and after the Cny were significantly lower in 2020 than in 2019 and 2021 in the same period,which further proves that the decrease in nO_(2)in February 2020 was attributed to the COVID-19 *** source analysis of an nO_(2)pollution episode during the lockdown period showed that the polluted air mass in the Beijing-Tianjin-Hebei was trans ported southwards under the action of the north wind,and the subsequent unfavorable meteorological conditions(local wind speed ofn the accumulation o pollutants.

关键词： MAX-DOAS Cnn-SVR nitrogen dioxide COVID-19 Chinese new year Regional transport