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2D phosphides heterostructures on titanium microfiltration membrane for enhanced ampere-level current density overall seawater splitting

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Nano Research 2025年第1期18卷 249-259页

作者： Wenjing Dai Xin Wang Yulong Ma Sisi He ming chen Zhaohui Yin Shuheng Tian Maolin Wang Shixiang Yu Hang Zhang Yuanzhe Wang Hong Wang Jianxin Li Faming Gao Bowen cheng Yun Wang Zhen Yin Ding Ma Tianjin Key Laboratory of Brine Chemical Engineering and Resource Eco-utilization College of Chemical Engineering and Materials ScienceTianjin University of Science and TechnologyTianjin 300457China State Key Laboratory of Biobased Fiber Manufacturing Technology Tianjin University of Science and TechnologyTianjin 300457China Haian Institute of High-Tech Research Nanjing UniversityHaian 226600China Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Separation Membranes and Membrane Processes Separation Membrane Science and Technology International Joint Research CentreTiangong UniversityTianjin 300387China Centre for Catalysis and Clean Energy School of Environment and ScienceGold Coast CampusGriffith UniversitySouthportQueensland 4222Australia

The advancement of direct seawater electrolysis is a significant step towards sustainable hydrogen production,addressing the critical need for renewable energy sources and efficient resource ***,direct seawater electrolysis has to face several challenges posed by the corrosiveness of highly concentrated chloride and the competitive chlorine evolution reaction(ClER).To overcome these issues,we designed a novel NiP_(2)@CoP electrocatalyst on a porous titanium microfiltration(Ti MF)*** obtained bifunctional NiP_(2)@CoP catalyst outperforms the Pt/C and IrO_(2),as evidenced by its low overpotentials of 192 and 425 mV at a current density of 500 mA·cm^(-2) for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in alkaline seawater(1 M KOH+0.5 M NaCl),***,only 231 and 569 mV overpotentials are required at the current density of 1500 mA·cm^(-2) towards HER and OER in alkaline seawater,*** importantly,no ClER was observed,demonstrating its excellent selectivity to *** selection of porous Ti MF membrane as an electrode substrate further enhances the performance by providing a robust structure that promotes the fast generation and release of gas *** promising outcomes obtained with NiP_(2)@CoP catalysts on Ti MF support,therefore,pave the way for the commercial viability of direct seawater electrolysis technologies at industrial-level current densities.

关键词： direct seawater electrolysis porous titanium microfiltration membrane phosphides heterostructures NiP_(2)@CoP electrocatalyst excellent selectivity to oxygen evolution reaction(OER)

Torsion Fields Generated by the Quantum Effects of Macro-bodies

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Research in Astronomy and Astrophysics 2022年第12期22卷 335-343页

作者： Da-ming chen National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

We generalize Einstein's General Relativity(GR)by assuming that all matter(including macro-objects)has quantum *** appropriate theory to fulfill this task is Gauge Theory Gravity(GTG)developed by the Cambridge *** is a“spin-torsion”theory,according to which,gravitational effects are described by a pair of gauge fields defined over a flat Minkowski background *** matter content is completely described by the Dirac spinor field,and the quantum effects of matter are identified as the spin tensor derived from the spinor *** existence of the spin of matter results in the torsion field defined over *** field plays the role of Bohmian quantum potential which turns out to be a kind of repulsive force as opposed to the gravitational potential which is *** equivalence principle remains and essential in this theory so that GR is relegated to a locally approximate theory wherein the quantum effects(torsion)are *** a toy model,we assume that the macro matter content can be described by the covariant Dirac equation and apply this theory to the simplest radially symmetric and static gravitational ***,by virtue of the cosmological principle,we are led to a static universe model in which the Hubble redshifts arise from the torsion fields.

关键词： cosmology:theory (cosmology:)dark matter (cosmology:)dark energy

Magnetic reconnection acceleration of astrophysical jets for different jet geometries

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Research in Astronomy and Astrophysics 2015年第4期15卷 475-482页

作者： a-ming chen Li-ming Rui College of Physical Science and Technology Central China Normal University

The acceleration mechanisms of relativistic jets are of great importance for understanding various astrophysical phenomena such as gamma-ray bursts, active galactic nuclei and microquasars. One of the most popular scenarios is that the jets are initially Poynting-flux dominated and succumb to magnetohydrodynamic instability leading to magnetic reconnections. We suggest that the reconnection timescale and efficiency could strongly depend on the geometry of the jet, which determines the length scale on which the orientations of the field lines change. In contrast to a usually- assumed conical jet, the acceleration of a collimated jet can be found to be more rapid and efficient （i.e. a much more highly saturated Lorentz factor can be reached） while the jets with lateral expansion show the opposite behavior. The shape of the jet could be formed due to the lateral squeezing on the jet by the stellar envelope of a collapsing massive star or the interaction of the jet with stellar winds.

关键词： gamma rays: bursts -- galaxies: jets -- MHD -- instabilities

Inducible direct plant defense against insect herbivores： A review

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Insect Science 2008年第2期15卷 101-114页

作者： ming-Shun chen USDA-ARS and Department of Entomology Kansas State University Manhattan Kansas 66506 USA

Plants respond to insect herbivory with responses broadly known as direct defenses, indirect defenses, and tolerance. Direct defenses include all plant traits that affect susceptibility of host plants by themselves. Overall categories of direct plant defenses against insect herbivores include limiting food supply, reducing nutrient value, reducing preference, disrupting physical structures, and inhibiting chemical pathways of the attacking insect. Major known defense chemicals include plant secondary metabolites, protein inhibitors of insect digestive enzymes, proteases, lectins, amino acid deaminases and oxidases. Multiple factors with additive or even synergistic impact are usually involved in defense against a specific insect species, and factors of major importance to one insect species may only be of secondary importance or not effective at all against another insect species. Extensive qualitative and quantitative high throughput analyses of temporal and spatial variations in gene expression, protein level and activity, and metabolite concentration will accelerate not only the understanding of the overall mechanisms of direct defense, but also accelerate the identification of specific targets for enhancement of plant resistance for agriculture.

关键词： chemical defense defensive protease lectins protease inhibitor secondary metabolite

Shock-produced akimotoite in the Suizhou L6 chondrite

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Science China Earth Sciences 2015年第6期58卷 876-880页

作者： chen ming XIE XianDe State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Key Laboratory of Mineralogy and Metallogeny Guangzhou Institute of Geochemistry Chinese Academy of Sciences

Shock-produced akimotoite was identified in the Suizhou chondritic meteorite, which occurs in two kinds of occurrence. The first is the irregular layers of akimotoite up to 4 ?m in thickness occurring in fractures and cracks of low-Ca pyroxene enclosed in the shock veins. The second is the zonal polycrystalline aggregates of akimotoite in shocked pyroxene grains close to the shock vein, where akimotoite occurs in a zonal area in between pyroxene and Mg Si O3-glass as irregular small clumps up to 5 ?m in size. This investigation suggests a solid-state transformation mechanism of pyroxene to akimotoite, and that akimotoite should have nucleated and grew in the area with abundant defects caused by shock deformation because the defect significantly enhances the solid-state reactivity and the kinetics of nucleation of high-pressure phase. The spatial relationship among the composed grains of pyroxene, akimotoite and Mg Si O3-glass(possibly vitrified perovskite) demonstrates a temperature gradient from the vein wall to the unmelted chondritic meteorite.

关键词： pyroxene akimotoite perovskite shock vein Suizhou meteorite

Multi-stage Dynamic Post-disaster Recovery Strategy for Distribution Networks Considering Integrated Energy and Transportation Networks

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CSEE Journal of Power and Energy Systems 2021年第2期7卷 408-420页

作者： Xinyi Jiang Jian chen ming chen Zhen Wei Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong UniversityJinan 250061China State Grid Qingdao Power Supply Company Qingdao 266002China

To improve the resilience of distribution networks(DNs),a multi-stage dynamic recovery strategy is proposed in this paper,which is designed for post-disaster DN considering an integrated energy system(IES)and transportation network(TN).First,the emergency response quickly increases the output of gas turbines(GTs)in the natural gas network(NGN),and responsively reconfigures the DN in microgrids,to maximize the amount of loads to be *** single-commodity flow model is adopted to construct spanning tree ***,in the second stage of energy storage recovery,mobile energy storage systems(MESSs)are deployed to cover the shortages of power demands,i.e.,to further restore the loads after evaluating the load recovery *** Floyd algorithm based dynamic traffic assignment(DTA)is selected to obtain the optimal path of the *** the third stage,the outputs of various post-disaster recovery measures are adjusted to achieve an economically optimized *** studies demonstrate the effectiveness of the proposed dynamic post-disaster recovery strategy.

关键词： Dynamic post-disaster recovery dynamic transportation network integrated energy system resilience distribution

Feasibility study of creep feed grinding of 300M steel with zirconium corundum wheel

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Chinese Journal of Aeronautics 2022年第3期35卷 565-578页

作者： Jiaqiang DANG Heng ZANG Qinglong AN Weiwei ming ming chen School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Mechanical Systems and Vibration Shanghai Jiao Tong UniversityShanghai 200240China

The ultrahigh strength 300M steel has been commonly used in the manufacture of aircraft landing gear and rotor shaft parts due to its excellent mechanical *** feed grinding is one of the essential operations during the whole component manufacturing *** this work,the feasibility of creep feed grinding of 300M steel by using the hard zirconium corundum wheel was theoretically and experimentally evaluated.A variety of responses including grinding forces,temperature fields,specific grinding energy,surface integrity and chip modes were carefully ***,the mechanism of ground surface profile generation and the spatial frequency spectrum of the surface profile were tentatively *** was found that the wheel speed has a relative influence on the grinding forces and temperatures of which the work hardening effect dominates the material removal with lower wheel speed while the thermal softening becomes crucial as the wheel speed exceeds the critical value for the studied 300M ***,a scattered spatial frequency spectrum for the generated surface profile was noticed with lower wheel speed while the spectrum gathers towards the lower frequency values with higher amplitude as the wheel speed *** shearing chip and flowing chip dominates the main chip type,indicating the excellent abrasive sharpness during the grinding *** general,the used zirconium corundum wheel presents feasibility for the creep feed grinding of 300M steel because of the high material removal rate,absence of surface burn,low wheel wear and higher compressive residual stresses.

关键词： 300M steel Chip formation Creep feed grinding Surface morphology Zirconium corundum wheel

Surface morphology characterization of unidirectional carbon fibre reinforced plastic machined by peripheral milling

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Chinese Journal of Aeronautics 2022年第2期35卷 361-375页

作者： Chongyan CAI Jiaqiang DANG Qinglong AN Weiwei ming ming chen School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

This paper aims to characterise surface morphology and 3D roughness parameters of unidirectional carbon fibre reinforced plastic(UD-CFRP)milled at 0°,45°,90°,and 135°fibre orientation angles(FOAs).Side milling experiments are conducted on UD-CFRP *** damage forms and texture direction of milled surface are *** frequency of defects on CFRP surface is quantitatively determined using radially averaged 2D *** kinematicdynamic surface topography is reconstructed considering feed,runout and vibration,then the ideal roughness parameters,S_(a),S_(q),S_(sk),and S_(ku)are calculated and compared with the measured ones,finally the material factor-induced roughness components are *** show that CFRP surface has no regular feed *** frequency of fibre breakage or surface defects is greater than tooth passing *** sorted by their average S_(a)in descending order is135°>90°>45°>0°,where surface defects contribute 93.9%,77.1%,73.2%,72.2%of the total roughness respectively,which suggests that surface defects show a more important role than tool kinematics and vibration in formation of milled *** negative Skewness(Ssk<0)and high Kurtosis(S_(ku)=4.0–11.5)of milled surface signify porosity and the presence of many anomalous deep valleys in milled surface,respectively.

关键词： Carbon fibre reinforced plastic(CFRP) Surface characterization Surface morphology Surface roughness Surface texture

Burr formation mechanism and morphological transformation critical conditions in grinding of nickel-based superalloy honeycomb cores

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Chinese Journal of Aeronautics 2023年第11期36卷 434-451页

作者： Haihang WANG Jie chen chenguang WANG Guoqiang GUO Qinglong AN Weiwei ming ming chen State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China AVIC chengdu Aircraft Industrial(Group)Co. Ltd.Chengdu 610092China Shanghai Spaceflight Precision Machinery Institute Shanghai 201600China

Nickel-based Superalloy Honeycomb(NBSH) is widely used in aerospace field due to the high temperature resistance, high specific strength and light weight. However, the NBSH is extremely prone to form burrs during processing. The unreasonable burr morphology causes insufficient welding strength or false welding between NBSH and skin, resulting in premature failure of the parts. Hence, the burr formation mechanism and morphological transformation critical conditions in grinding NBSH were investigated based on finite element method(FEM) and experiments. Furthermore, the orthogonal experiments were carried out to investigate the effects of grinding parameters on burr and obtain the suitable parameter intervals to restrain the flash burr formation. The results indicate that due to the absence of supporting material, the extruded material of edge transforms into the Fourth Deformation Zone(FDZ). The FDZ rotates a certain angle due to the extrusion of abrasive particle, which leads to the fact that the FDZ cannot be removed and remains on the honeycomb wall, thus forming micro burr. If the material removal per unit time is large, the chip is not removed from FDZ. The parts that should have been chips are bonded with micro burr to form a flash burr. To restrain the flash burr formation, the suitable intervals of grinding depth,grinding speed and feed speed are 5–15 μm, 60–70 m/min and 500–1000 mm/min, respectively.

关键词： Burr Grinding Honeycomb Mechanism Nickel-based superalloy