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Professor Jiang Zhouhua's team from Northeastern University published the latest research results in the journal Nature
Recently, the team of Professor Jiang Zhouhua of the School of Metallurgy of Northeastern University has made an important breakthrough in the innovative design of improving the corrosion resistance of stainless steelThe related results "Design for improving corrosion resistance of Duplex stainless steels by wrapping inclusions with Niobium Armour" were publishedNature Communications。**The authors are Zhang Shucai, Feng Hao, Li Huabing, Jiang Zhouhua, Zhang Tao, Zhu Hongchun, Lin Yue, Zhang Wei, Li Guoping, among them, the first author is Zhang Shucai, a lecturer at the School of Metallurgy, and the corresponding author is Professor Li Huabing, Key Laboratory of Ecological Metallurgy of Polymetallic Symbiotic Minerals of the School of Metallurgy. The School of Metallurgy of Northeastern University is the first completion unit, and Professor Zhang Tao of the School of Materials Science and Engineering of Northeastern University, Dr. Zhang Wei of CITIC Metal and Li Guoping, a professor-level senior engineer of Shanxi Taigang Stainless Steel Co., Ltd., are the completion of the cooperation.
The corrosion failure of steel materials can not only lead to catastrophic safety accidents, but also cause huge economic losses. In order to meet the needs of infrastructure and equipment for long life, a series of highly corrosion-resistant stainless steels have been developed. However, as the service environment becomes more demanding, these stainless steels can still corrode. Non-metallic inclusions are one of the main causes of corrosion, which usually cause the serious impact of "a thousand miles of embankment, collapse in an anthill", and its harm is particularly prominent in extremely harsh environments such as high temperature and high chlorine. In this regard, researchers have explored many ways to reduce the hazards of inclusions, such as deep deoxidation, deep desulfurization and modification. However, these methods have limited effectiveness, and corrosion can still occur in inclusions or the surrounding matrix. Therefore, how to effectively prevent corrosion failure caused by inclusions has become an urgent challenge in the field of corrosion protection of steel materials.
This study breaks the traditional thinking limitation of "relying on cleanliness control and modification treatment to reduce the hazard of inclusions", and innovatively proposes the strategy of "using corrosion-resistant niobium armor (Z phase) to wrap harmful inclusions to significantly improve the corrosion resistance of duplex stainless steel". This strategy skillfully applies the principles of microalloying and heterogeneous nucleation to achieve two key objectives: effective encapsulation of inclusions containing niobium Z-phase (Fig. 1) and good corrosion resistance of z-phase and surrounding matrix (Fig. 2).
Fig.1 Characterization of niobium-containing Z-phase encapsulated inclusions ("inclusion @z-phase" core-shell structure) in S32205 duplex stainless steel.
Fig.2 Comparison of corrosion resistance of niobium-containing and non-niobium-free S32205 duplex stainless steels in 72 times the concentration of seawater (A-C) and 50 6% FeCl3 solution (D-G).
In this study, we used corrosion-resistant "niobium armor" (Z-phase) to wrap harmful inclusions, which overcame the long-standing problem of "corrosion failure caused by inclusions", and had strong universality in series of duplex stainless steels (S32101, S32304, S32205, S32507, S32707) and industrial production (Fig. 3). This research provides a new idea for the corrosion protection of stainless steel materials, and is of great significance to ensure the long life and safe and stable operation of high-end equipment.
Fig.3 Verification of the universality of the strategy to improve corrosion resistance with niobium-containing Z-phase encapsulated inclusions (B-D corrosive environment: 72 times the concentration of seawater).
Professor Xu Dake of Northeastern University and others have published the latest research results in the internationally renowned journal Advanced Functional Materials
Recently, Professor Xu Dake and others from the team of Wang Fuhui of the School of Materials Science and Engineering of Northeastern University have made important progress in the use of living functional microbial film materials in metal corrosion protectionThe research results were published under the title of "engineered living biofilm with enhanced metal binding ability for corrosion protection in seawater".advanced functional materialsAbove. **The first author is Associate Professor Li Zhong, and the corresponding authors are Professor Xu Dake and Professor Fan Yongqiang of the School of Life Science and Health. Collaborators include Associate Professor Guangming Jiang of Wollongong University in Australia and Professor Tingyue Gu of Ohio University in the United States.
The economic losses caused by the corrosion failure of metal materials account for 3About 5%. Traditional corrosion protection methods include coatings, surface treatments, corrosion-resistant materials, corrosion inhibitors, electrochemical protection, etc. Although these technologies have their own advantages, they still face many inherent shortcomings and shortcomings, such as high environmental pollution, high energy consumption, and high maintenance costs. Green, efficient and inexpensive corrosion protection concepts and technologies are the urgent needs and beautiful visions of today's social development. The application of live microbial film in metal corrosion protection has many natural advantages, such as low cost, green environmental protection, wide application range, and strong genetic manipulation.
In recent years, researchers have developed a variety of living biofilm materials with functions such as environmental remediation, medical applications, biocatalysis, and underwater adhesion through surface modification, signaling pathway regulation, and assembly with inorganic materials. The relevant research provides a theoretical basis and technical support for the development of living functional microorganisms for metal corrosion protection.
*Using Escherichia coli as the chassis strain, the genome was modified by molecular biology technology to enhance its biofilm formation ability, and the metal binding domain originating from Pseudomonas aeruginosa was displayed on the surface of amyloid fibrin of living E. coli through synthetic biology technology, and an engineered E. coli biofilm with strong metal binding ability was constructed. Engineered living microbial film improves the corrosion resistance of X70 carbon steel. After immersion in simulated seawater, the living microbial film also induces the formation of a calcite-dominated mineralized layer on the surface of X70, providing a stable corrosion barrier. After 7 days of immersion, the corrosion current density increased from 51±0.4 acm2 (bare metal) reduced to 05±0.1 acm2 (mineralized biofilm encapsulation) with corrosion inhibition of 902%。In addition, the living engineered biofilm also has a good anti-corrosion effect on 304 stainless steel.
The above results show that engineering biofilms have a wide range of application prospects for metal corrosion protection, and the application of synthetic biology provides a new way for the development of metal corrosion protection technology in water environment.
Figure: Design and preparation of living functional biofilm for metal corrosion protection.
It is reported that living functional materials are a new type of functional materials that give the life behavior of organisms to material carriers, which belongs to the interdisciplinary research field of biology and materials science, and the research direction has just started in China. It is of great practical significance to integrate the technical means of materials science and microbiology and the global design to realize the specific function and application of intelligent synthetic microbial films. Living functional materials will be one of the important research directions of the Interdisciplinary Research Center for Electroactive Biomaterials of Northeastern University, focusing on the "four aspects" and doing a good job in the development of disciplines.
The latest research results of Professor Zhao Yuhai's team at Northeastern University have been accepted by AAAI2024, a top conference in the field of artificial intelligence
Recently, the team of Professor Zhao Yuhai from the School of Computer Science and Engineering of Northeastern University has made the latest research progress in the field of multi-label learning. **"Limited-supervised multi-label learning with dependency noise" wasAAAI 2024, the top international conference in the field of artificial intelligence(Annual AAAI Conference on Artificial Intelligence)
AAAI is a Class A international academic conference recommended by the CCF and enjoys a high academic reputation in the field of artificial intelligence. A total of 9,862 submissions were received at this conference, and 2,342 were accepted, with an acceptance rate of about 2375%。The achievement of this research achievement marks that the scholars of the School of Computer Science and Engineering have made great progress in the field of artificial intelligence, and the research level and ability have been widely recognized by peers at home and abroad, which has effectively enhanced the academic influence and contribution of our university in related fields, and laid a good foundation for the future exchanges and interactions between our scholars and international top scholars.
*The first author is team member Dr. Yejiang Wang. The research was jointly conducted by researchers from Northeastern University and Singapore Technological University. **This paper innovatively proposes a noise-dependent finitely supervised multi-label learning method, focusing on solving the problem of label noise in the training of multi-label classification models. Compared with previous studies, this method considers the actual situation that label noise is related to input features and class labels, and provides an innovative solution to solve this problem by identifying both instance-related and label-related label noise. In addition, the problem is regularized by introducing manifold constraints to maintain local relationships and reveal the manifold structure of the data. This comprehensive method theoretically provides a solid theoretical basis for solving practical problems by setting the upper bound of the noise recovery error. The final experimental proof shows that the method is effectiveIt exhibits excellent performance in terms of label noise, which provides an innovative and practical contribution to the development of the field of multi-label learning.
The team of associate professor Mao Yupeng of Northeastern University published the latest research results in the internationally renowned journal Advanced Functional Materials
Recently, the micro-nano intelligent sports research team of Associate Professor Mao Yupeng of the Department of Physical Education of Northeastern University has made breakthroughs in the field of biomass triboelectric sensing to empower sports healthThe research results were published under the title of "Deep-learning-assisted neck motion monitoring system self-powered through biodegradable triboelectric sensors".Advanced Functional Materials, an internationally renowned journalAbove. Sun Fengxin, a 2021 master's student of the Ministry of Physical Education, is the first author, Associate Professor Mao Yupeng is the corresponding author, and Northeastern University is the first unit and corresponding unit.
In the new era of artificial intelligence and the Internet of Things, smart sports big data collection and analysis is of great significance in monitoring human health. Wearable electronics integrate advanced sensors and data analysis algorithms that can analyze human health in real time and accurately track and record human activity, providing unprecedented opportunities for personalized health monitoring and exercise training. It should be pointed out that the limitations of traditional battery-powered devices limit the application of wearable electronics in the field of motion monitoring. For example, frequent battery replacement or recharging, as well as discarded batteries, not only lead to environmental pollution, but also make it difficult to monitor the movement process in real time.
In this work, a self-powered biodegradable triboelectric sensor was developed by using the natural biodegradable biomass material, corn bract, as the dielectric layer, combined with triboelectric nanopower generation technology. This study avoids the environmental pollution caused by the burning of corn bracts, realizes the collection of human mechanical energy, and realizes the intelligent monitoring of human movement.
Figure Device fabrication and structural characterization.
In order to realize the monitoring of neck stability during exercise and the prevention of neck diseases in daily life, the team integrated three identical NB-TENG sensors with elastic stretchable textiles to obtain a wearable neck condition monitoring sensor (NCM-TS). By combining NCM-TS with a deep learning model, an intelligent behavior monitoring system was constructed, which was able to identify four types of neck movements with an average accuracy of 94%. The neck motion monitoring sensor developed in this study has a wide range of application potential in smart sports big data collection, sports monitoring, training and healthcare.
Figure: Intelligent behavior monitoring system integrating deep learning-assisted data analysis.
Professor Li Li's team at Northeastern University has made important research progress in the field of metal anodes for lithium metal batteries
Recently, Professor Li Li's team at Northeastern University has made important progress in the field of metal anodes for lithium metal batteries. The related results "A crystalline carbon nitride based separator for high-performance lithium metal batteries" were publishedTop international journalsproceedings of the national academy of sciences of the united state of america(pnas)。Northeastern University is the first author of the first author, and Di Xuanlong, a doctoral student in the School of Science, Northeastern University, and Li Honghong, a doctoral student in the School of Metallurgy, are the co-first authors.
Lithium metal batteries have higher energy density and have broad application prospects in the new generation of electrochemical energy storage. As the anode of the battery, lithium metal has a high theoretical capacity, but the uneven deposition in the cycle process is easy to develop into the growth of dendrite form, which shows poor stability and brings certain safety hazards, which restricts the development of lithium metal batteries.
The growth of lithium dendrites is inhibited by the use of carbon nitride with high crystallinity as a separator modification layer. The extended conjugated structure in high-crystallinity carbon nitride makes electrons more migratory, and the chloride ion and high content of pyrrole nitrogen in the structure enhance the interaction with lithium ions. The experimental results show that the carbon nitride modified layer with high crystallinity can homogenize the ion flux, realize the uniform deposition of lithium, and improve the stability of symmetrical battery and Li LiFePO4 whole battery.
Figure Structure of highly crystalline carbon nitride and its application in lithium metal batteries.
This work regulates carbon nitride materials through crystallinity engineering, expands the application of carbon nitride-based materials in advanced battery systems, and also provides new insights for the design of functionalized separators for lithium metal batteries.
The research group of rare earth magnetic materials of the Key Laboratory of EPM of the Ministry of Education of Northeastern University published new results in SMALL
Recently, the Rare Earth Magnetic Materials Research Group of the Key Laboratory of Materials Electromagnetic Processes of the Ministry of Education of Northeastern University was published in the journal SMALLThe paper entitled "In-plane Chemical Ordering (Mo2 3R1 3)2ALB2 (R = TB, DY, HO, ER, TM and Lu) I-Mab Phases and Their Two-dimensional Derivatives (MBENE): Synthesis, Structure, Magnetic and SuperCapacitor." performance**. Northeastern University is the first corresponding unit, and the doctoral student of the School of Materials Science and Engineering, He Chong, is the first author, and Professor Cui Weibin is the corresponding author.
The development and utilization of new energy has become the mainstream of future energy development, including wind energy, hydropower, nuclear energy and other energy technologies have been widely used. However, energy storage is an unavoidable issue, and supercapacitors are a new type of energy storage and conversion device that not only has a high energy density, but also has a high power density, and is a technology that can solve the growing energy demand in the era of energy shortage. Two-dimensional materials, represented by MXENE, have a wide range of applications in the field of new energy.
MXENE is a two-dimensional transition metal carbonitride obtained from the MAX phase by topological chemical etching, which inherits the relatively single sixth-order symmetrical structure of the MAX phase precursor, and has the characteristics of large specific surface area, rich chemical composition, and diverse and adjustable surface functional groups, which has great application potential in the field of energy storage and conversion. Unlike the MAX phase, which mainly crystallizes in the hexagonal space group of P63 MMC, the MAB phase, a borate analogue of the MAX phase, tends to have rich crystal structures (e.g., CMCM, CMMM, PMMM) due to the underelectron properties of boron. The prospect of chemical excretion of the MAX phase into 2D MXENE has also attracted the attention of researchers, so the development of a new 2D MAB phase precursor is of great significance for the application of its 2D derivative MBENE.
In this study, a series of rare earth ordered occupancy layered borides (Mo2 3R1 3)2Alb2 (R = TB, DY, HO, ER, TM, LU) I-mAb phases were synthesized and characterized. The crystal structure of (Mo2 3R1 3)2Alb2 is R-3M hexagonal structure, and the Mo atoms and rare earth R atoms are arranged in an orderly and alternating manner in the Mo-R layer, where the R atoms are located in the center of the regular hexagonal shape of the Mo atoms and slightly protrude from the Mo-R layer to the Al layer (Fig. 1).
Fig. 1 XRD refinement of (a) (MO2 3HO1 3)2ALB2 and (b) comparison of unit cell parameters of (MO2 3HO1 3)2ALB2(mo2 3ho1 3)2alb2 electron diffraction images of STEM-HAADF and selective regions along (c)[100], d)[-110], e)[001] axes.
Due to the spin interaction of the 4f electrons of the rare earth atom, the (Mo2 3R1 3)2Alb2 compound exhibits an external field-induced magnetic moment flip phenomenon at low temperatures, and the critical field required for the magnetic moment flip gradually decreases from R=TB to TM as the magnetocrystalline anisotropy field gradually weakens (Fig. 2).
Fig. 2 (mo2 3ho1 3)2alb2(r = (a)tb, (b)dy, (c)ho, (d)er, (e)tm) at 0This thermal curve at a 1 t outfield;(mo2 3ho1 3)2alb2(r = (f)tb, (g)dy, (h)ho, (i)er, (j)tm) isothermal curves at different temperatures;(mo2 3ho1 3)2alb2(r = (k)tb, (l)dy, (m)ho, (n)er, (o)tm)4 k isothermal This curve corresponds to the DM d 0h curve.
By selectively etching away the Al layer and R atoms in (Mo2 3R1 3)2Alb2 by topological chemistry, a two-dimensional derivative MBENE with R ordered vacancies and maintaining the sixth-order symmetry of the (Mo2 3R1 3)2Alb2 parent phase is obtained (Fig. 3). After 773 K nitriding treatment, it still maintains a sixth-order symmetry and layered structure, and its charge transfer resistance is greatly reduced compared with the original mbene, and the mass specific capacitance is greatly increased to 219 F g (at a scan rate of 2 mV), which is due to the decomposition and deintercalation of interlayer ions and the introduction of Mo-N bonds. Further increasing the nitriding temperature to 973 K converts MBENE into a poorly crystalline crystalline Mo2N nanosheet with a mass specific capacitance of 229 F g (at a scan rate of 2 mV) (Figure 4).
Fig.3 MBENE STEM-HAADF image with the corresponding fast Fourier transform (inset).
Fig.4 mbene@ho, mbene@ho-N573K, mbene@ho-N773K, mbene@ho-N973K (a) CV curves at 50mV s sweep speed, (B) mass specific capacitance, (C) NYQUIST plot, (D) B-value fitting results of mbene@ho-N973K.
In this study, we broadened the nanolayered boride system with rare earth order occupancy, and explored the crystal structure and magnetic properties of the systemThrough topological chemical etching, rare earth elements are combined with two-dimensional energy storage systems, which broadens the application of rare earth elements in supercapacitors.
The team of Professor Yi Tingfeng of Northeastern University Qinhuangdao has made an important breakthrough in the field of rechargeable zinc-air battery oxygen electrocatalysts
Recently, the team of Professor Yi Tingfeng from the School of Resources and Materials at Northeastern University Qinhuangdao has made important progress in the field of rechargeable zinc-air battery oxygen electrocatalystsThe research result "self-assembled 3D n p s-tridoped carbon nanoflower with highly branched carbon nanotubes as efficient bifunctional oxygen electrocatalyst towards high-performance rechargeable." ZN-Air Batteries" (self-assembled three-dimensional nitrogen, phosphorus, sulfur, and tridoped carbon nanoflowers with highly branched carbon nanotubes as effective bifunctional oxygen electrocatalysts for high-performance rechargeable zinc-air batteries) was published in the field of materialsInternationally renowned publicationsadvanced functional materials。Chang Hui, a Ph.D. student in materials science and engineering at Qinhuangdao University, is the first author of this paper, and Professor Yi Tingfeng and Associate Professor Zhang Qianyu of Sichuan University are the corresponding authors. Northeastern University is the first completion unit.
Rechargeable zinc-air battery (ZAB) is a promising new energy storage device for electric vehicles due to its high theoretical energy density, low cost, abundant resources and environmental friendliness. The air electrode is a key factor in determining the performance of the battery, and the slow oxygen reduction (ORR) and oxygen evolution reaction (OER) on the air electrode are the key factors that lead to the degradation of battery performance. The commercialization of ZABS is largely limited by the high cost of traditional catalysts, such as PT-based catalysts for ORR and RUO2 IRO2 catalysts for OER. Therefore, it has become a trend to develop non-oxygen electrocatalysts with low cost, high activity and good stability. Among them, the three-dimensional structure can reduce the diffusion resistance between the gas and the electrolyte inside the catalyst, expand the contact between the active site and the reactants, and maximize the performance of the catalyst.
Metal-organic frameworks (MOFs) are excellent precursors because MOFs not only complex with organic ligand-bridging metal nodes to provide transition metals, carbons, and heteroatoms for catalysis, but also have controlled periodicity. MOF-derived carbon-based catalysts are widely used in catalytic reactions due to their excellent conductivity and abundant active sites. Improving the electrocatalytic activity of a sample by controlling the morphology and structure of MOFs is one of the most commonly used methods. The formation of a three-dimensional structure through self-assembly can effectively inhibit the self-aggregation of traditional nanosheet reactions and ensure the effective exposure of active sites. However, the synthesis of three-dimensional MOFs requires specific organic solvents (e.g., DMF, methanol), which seriously increases the synthesis cost of MOFs. Therefore, it is of great significance to transform MOFs into three-dimensional porous materials through suitable self-assembly methods to promote the rapid transfer of electrons.
In addition, the composition of the catalyst is a key criterion. The heteroatom (NPS b) doping strategy and the synergistic effect of metal active sites promote the ORR and OER processes. The electronegativity of heteroatoms and the difference in atomic size can induce nitrogen-doped carbon materials to produce higher spin density and electron delocalization, thereby enhancing ORR OER activity.
Figure Design and structural model of the CO SP-NC catalyst.
Based on this, the research team prepared a three-dimensional nitrogen-phosphorus-sulfur-triple-doped nanoflower bifunctional catalyst (CO SP-NC) with highly branched carbon nanotubes, which mainly used ammonium sulfate as the surfactant and sodium hypophosphite as the reducing agent. Ammonium sulfate drives the self-assembly of two-dimensional Zn Co-ZIF into three-dimensional nanoflowers while providing active S atoms. In addition, sodium hypophosphite induces the formation of highly branched carbon nanotubes on the surface of three-dimensional Zn Co-zif nanoflowers.
In addition, first-principles calculations confirmed that the introduction of nitrogen, phosphorus, and sulfur could effectively activate water and oxygen molecules, while forming a large number of defect sites and changing the coordination environment around CO species, greatly increasing the number of active centers. At the same time, the results show that proper P doping can not only improve the electronic conductivity of the substrate, but also help to improve the charge transfer during OER ORR. The prepared CO SP-NC electrocatalyst has good bifunctional activity and a half-wave potential of 08603 V, overpotential at 10 mA cm-2 is 343 mV. The zinc-air battery assembled by CO SP-NC has an ultra-high power density (187 MW cm2) and good cycling performance (over 280 h). This work provides a controlled method for the fabrication of three-dimensional self-assembled nanoflowers, especially for rechargeable zinc-air batteries.
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