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One-dimensional molecular co-crystal alloys capable of full-color emission for low-loss optical waveguide and optical logic gate

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Aggregate 2024年第1期5卷 299-308页

作者： Zhenhong Qi Yu-Juan Ma Dongpeng Yan Beijing key laboratory of energy Conversion and Storage Materials College of ChemistryKey Laboratory of Radio-pharmaceuticals Ministry of EducationBeijing Normal UniversityBeijingChina

The luminescence color of molecule-based photoactive materials is the key to the applications in lighting and optical *** continuous regulation of emission color in molecular systems is highly desirable but still remains a challenge due to the individual emission band of purely organic ***,a novel alloy strategy based on molecular co-crystals is *** adjusting the molar ratio of pyrene(Py)and fluorathene(Flu),three types of molecular co-crystal alloys(MCAs)assemblies are prepared involving Py-Flu-OFN-x%,Py-Flu-TFP-x%,Py-Flu-TCNB-x%.Multiple energy level structure and Förster resonance energy transfer(FRET)process endow materials with tunable full-spectra emission color in visible ***,these MCAs and co-crystals can be successfully applied to low optical loss waveguide and optical logic gate by virtue of all-color luminescence from blue across green to red,together with smooth surface of onedimensional microrods,which show promising applications as continuous light emitters for advance photonics applications.

关键词： full-color emission microrods molecular co-crystal optical waveguide organic alloys

Sodium Nitrate/Formamide Deep Eutectic Solvent as Flame-Retardant and Anticorrosive Electrolyte Enabling 2.6 V Safe Supercapacitors with Long Cyclic Stability

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energy & Environmental Materials 2024年第3期7卷 378-387页

作者： Huachao Yang Yiheng Qi Zifan Wang Qinghu Pan Chuanzhi Zhang Jianhua Yan Kefa Cen Zheng Bo Kostya (Ken) Ostrikov State key laboratory of Clean energy Utilization College of Energy Engineering Zhejiang University School of Chemistry and Physics and QUT Centre for Materials Science Queensland University of Technology (QUT)

Safe operation of electrochemical capacitors （supercapacitors） is hindered by the flammability of commercial organic ***-flammable Waterin-Salt （WIS） electrolytes are promising alternatives; however,they are plagued by the limited operation voltage window （typically≤2.3 V） and inherent corrosion of current ***,a novel deep eutectic solvent（DES）-based electrolyte which uses formamide （FMD） as hydrogen-bond donor and sodium nitrate （NaNO3） as hydrogen-bond acceptor is *** electrolyte exhibits the wide electrochemical stability window （3.14 V）,high electrical conductivity (14.01 mS cm-1),good flameretardance,anticorrosive property,and ultralow cost （7%of the commercial electrolyte and 2%of WIS）.Raman spectroscopy and Density Functional Theory calculations reveal that the hydrogen bonds between the FMD molecules and NO3-ions are primarily responsible for the superior stability and *** developed NaNO3/FMD-based coin cell supercapacitor is among the best-performing state-of-art DES and WIS devices,evidenced by the high voltage window （2.6 V）,outstanding energy and power densities(22.77 Wh kg-1at 630 W kg-1and 17.37 kW kg-1at 12.55 Wh kg-1),ultralong cyclic stability （86%after 30 000 cycles）,and negligible current collector *** NaNO3/FMD industry adoption potential is demonstrated by fabricating 100 F pouch cell supercapacitors using commercial aluminum current collectors.

关键词： cyclic stability deep eutectic solvents electrical conductivity electrochemical stability window supercapacitors

Chalcogen heteroatoms doped nickel-nitrogen-carbon single-atom catalysts with asymmetric coordination for efficient electrochemical CO_(2)reduction

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Chinese Journal of Catalysis 2024年第9期64卷 54-65页

作者： Jialin Wang Kaini Zhang Ta Thi Thuy Ng Yiqing Wang Yuchuan Shi Daixing Wei Chung-Li Dong Shaohua Shen International Research Center for renewable energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049ShaanxiChina Department of Physics Tamkang UniversityNew Taipei City 25137TaiwanChina

The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2)reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N4-C)configuration to obtain Ni-X-N3-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni *** these obtained Ni-X-N3-C(X:S,Se,and Te)SACs,Ni-Se-N3-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98%at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2)battery integrated with Ni-Se-N3-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm-2 and maintained remarkable rechargeable stability over 20 ***-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N4-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)***,for Ni-Se-N3-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of*COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction.

关键词： Electrochemical CO_(2)reduction reaction Chalcogen heteroatoms Single-atom catalysts Asymmetric coordination CO production

Fault Diagnosis Method of Rolling Bearing Based on MSCNN-LSTM

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Computers, Materials & Continua 2024年第6期79卷 4395-4411页

作者： Chunming Wu Shupeng Zheng key laboratory of Modern Power System Simulation and Control&renewable energy Technology Ministry of EducationNortheast Electric Power UniversityJilin132012China Ministry of Education Northeast Electric Power UniversityJilin132012China

Deep neural networks have been widely applied to bearing fault diagnosis systems and achieved impressive success *** address the problem that the insufficient fault feature extraction ability of traditional fault diagnosis methods results in poor diagnosis effect under variable load and noise interference scenarios,a rolling bearing fault diagnosis model combining Multi-Scale Convolutional Neural Network(MSCNN)and Long Short-Term Memory(LSTM)fused with attention mechanism is *** adaptively extract the essential spatial feature information of various sizes,the model creates a multi-scale feature extraction module using the convolutional neural network(CNN)learning *** learning capacity of LSTM for time information sequence is then used to extract the vibration signal’s temporal feature *** parallel large and small convolutional kernels teach the system spatial local *** gathers temporal global features to thoroughly and painstakingly mine the vibration signal’s characteristics,thus enhancing model ***,bearing fault diagnosis is accomplished by using the SoftMax *** experiment outcomes demonstrate that the model can derive fault properties entirely from the initial vibration *** can retain good diagnostic accuracy under variable load and noise interference and has strong generalization compared to other fault diagnosis models.

关键词： Bearing fault diagnosis convolutional neural network short-long-term memory network feature fusion

Highly sensitive fluorescent sensing and photocatalytic degradation performance of two-dimensional Tb-organic network

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Journal of Rare Earths 2024年第2期42卷 303-313,I0003页

作者： Ting Gao Zhihu Ma Yixia Ren Zhixiang Wang Meili Zhang Xiaoli Chen Jijiang Wang laboratory of New energy and New Function Materials Shaanxi Key Laboratory of Chemical Reaction EngineeringCollege of Chemistry and Chemical EngineeringYan'an UniversityYan'an716000China

A novel tetra-nuclear Tb-organic network,named as [Tb_(4)(2-pyia)_(6)(HAc)_(0.5)(2,2'-bipy)(H_(2)O)_(4.5)]·2,2'-bipy·H_(2)O(1),was synthesized hydrothermally based on 5-(pyridin-2-ylmethoxy) isophthalic acid(H_(2)pyia) and 2,2'-bipyridine(2,2'-bipy) ligands,and characterized by single crystal X-ray diffraction,thermogravimetric(TG) analyses,powder X-ray diffraction(PXRD) and infrared(IR) technology.1 possesses a two-dimensional network based on the tetra-nuclear inorganic building units,and the π-πstacking interactions between the pyia^(2-) ligands and the guest 2,2'-bipy molecules play an important role in the forming of 3D supramolecular structure.1 exhibits excellent fluorescent sensing performance for Fe^(3+)(1.26×10^(-8) mol/L),Cr_(2)O_(7)^(2-)(8.1×10^(-7) mol/L),2,4,6-trinitrophenol(TNP)(2.71×10^(-8) mol/L)and tetracycline(TCT)(2.76×10^(-7) mol/L) in aqueous solution with lower detection *** sensing mechanisms of 1 were investigated by density functional theory(DFT) calculations,ultraviolet-visible(UV-Vis) diffuse reflectance spectroscopy,PXRD and fluorescent lifetime *** activated product of 1 was prepared by heating at 255℃ under constant pressure and used to photo-catalytically degrade *** 1 and the activated one have good photocatalytic degradation performance for TCT with degradation rates of 84.29% and 96.07%,*** photocatalytic mechanisms were discovered by UV-Vis diffuse reflectance spectroscopy and radical trap *** Tb-organic framework might be an excellent multifunctional fluorescent sensor and a good photocatalytic agent for TCT degradation in the future.

关键词： Tb-organic network Fluorescent sensing Photocatalytic degradation Rare earths

A small organic molecule strategy for remedying oxygen vacancies by bismuth defects in BiOBr nanosheet with excellent photocatalytic CO_(2)reduction

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Nano Research 2024年第1期17卷 297-306页

作者： Jing Xie Zhenjiang Lu Yue Feng Jianguo Huang Jindou Hu Aize Hao Yali Cao State key laboratory of Chemistry and Utilization of Carbon Based energy Resources College of ChemistryXinjiang UniversityUrumqi 830046China

Defect modulation currently plays a decisive role in addressing the poor photoabsorption,sluggish electron hole separation,and high CO_(2)activation barrier in photocatalytic CO_(2)***,hunting for a straightforward strategy to balance the concentration of oxygen vacancy and metal cation defect in one photocatalyst is still a great ***,a bismuth vacancies BiOBr nanosheets(BiOBr-1)on the exposed[001]facets were constructed via an acetic acid molecule modification strategy,which can repair oxygen defect by bismuth vacancy in low-temperature solid-state chemical *** from the formed bismuth defects that can not only broaden light absorption and elevate charge separation efficiency,but also enhance adsorption and activation of CO_(2)molecules,the evolution rates of photocatalytic CO_(2)conversion into CO(71.23μmol·g^(-1)·h^(-1))and CH4(8.90μmol·g^(-1)·h^(-1))attained by BiOBr-1 are superior 7.1 and 11 times to that of plate-like *** photocatalytic mechanisms including adsorption concentration and activation process of CO_(2)are further revealed by the in situ diffuse reflectance infrared flourier transform spectra(DRIFTS).This finding of the existence of distinct defects in ultrathin nanosheets undoubtedly leads to new possibilities for photocatalyst design using two-dimensional materials with high solar-driven photocatalytic activity.

关键词： solid-state synthesis BiOBr metal vacancies photocatalysis carbon dioxide reduction

Cobalt-doped TiO_(2)@C hierarchical nanocomposites derived from Ti_(3)C_(2) MXene as cathodes for hybrid magnesium-lithium batteries

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Nano Research 2024年第1期17卷 253-261页

作者： Xiaohui Li Yakun Tang Lang Liu Yue Zhang Yang Gao Mao Qian Wenjie Ma State key laboratory of Chemistry and Utilization of Carbon Based energy Resources College of ChemistryXinjiang UniversityUrumqi 830017China

TiO_(2)has been explored in hybrid magnesium-lithium batteries(HMLBs)due to the advantages of low self-discharge and small volume expansion during ion ***,how to improve the inherently low ionic and electrical conductivity of TiO_(2)is the problem that needs to be *** this work,a smart strategy is adopted to prepare cobalt-doped TiO_(2)@C(Co^(4+)-TiO_(2)@C)hierarchical nanocomposite derived from Co(II)(OH)n@*** with TiO_(2)@C(without cobalt doping),Co^(4+)-TiO_(2)@C shows the highest specific capacity(154.7 mAh·g^(-1)at 0.1 A·g^(-1)after 200 cycles)and extraordinary rate performance in *** excellent electrochemical performance of Co4+-TiO_(2)@C is ascribed to the synergistic effect of the hierarchical structure and *** experimental results and density functional theory(DFT)calculation reveal that the cobalt-doping has effectively improved the electronic conductivity and reduced the Li+migration *** work provides a new insight to design TiO_(2)-based cathode materials with high-performance in HMLBs.

关键词： Ti_(3)C_(2)MXene TiO_(2) hybrid magnesium-lithium batteries hierarchical structure cobalt-doping

Increasing operational stability of journal bearing in hydraulic suspension micro-pump by herringbone grooved structure

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Science China(Technological Sciences) 2024年第3期67卷 853-862页

作者： HONG Tao XING GuanYing ZUO HuaiYu XUE Song LUO XiaoBing State key laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The operational stability of radial journal bearings is the bottleneck that limits the reliability of hydraulic suspension micropump. Due to self-excited vibrations, the whirl amplitude of the plain journal bearing(PJB) is large at high rotational speeds,which will accelerate wear failure. It has been proven that employing herringbone grooved journal bearing(HGJB) is an effective method to reduce the whirl amplitude and improve operational stability. However, enhancing the stability of journal bearings in micro-pumps by herringbone grooved structures has rarely been studied, and its effect needs to be verified. We validated the mechanism of the stability improvement with the CFD method and compared the dynamic characteristics of HGJB and PJB by rotor dynamics evaluation and experiment. The experimental results show that under the same conditions the whirl amplitude of the HGJB decreases by 29.61% in the x direction and by 24.09% in the y direction compared with that of the PJB. This study reveals the effect of the herringbone grooved structure on the operational stability of bearings and may provide guidance for the reliability improvement of hydraulic suspension micro-pump.

关键词： journal bearing herringbone groove hydrodynamic effect micro-pump

Selective Hydrodeoxygenation of Lignin-Derived Vanillin via Hetero-Structured High-Entropy Alloy/Oxide Catalysts

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energy & Environmental Materials 2024年第3期7卷 206-214页

作者： Yan Sun Kaili Liang Ren Tu Xudong Fan Charles Q.Jia Zhiwen Jia Yingnan Li Hui Yang Enchen Jiang Hanwen Liu Yonggang Yao Xiwei Xu key laboratory for Biobased Materials and energy of Ministry of Education College of Materials and EnergySouth China Agricultural University Department of Chemical Engineering and Applied Chemistry University of Toronto State key laboratory of Materials Processing and Die & Mould Technology School of Materials Science and EngineeringHuazhong University of Science and Technology

The chemoselective hydrodeoxygenation of natural lignocellulosic materials plays a crucial role in converting biomass into value-added *** their complex molecular structures often require multiple active sites synergy for effective activation and achieving high ***,it is reported that a high-entropy alloy (HEA) on high-entropy oxide (HEO)hetero-structured catalyst for highly active,chemoselective,and robust vanillin *** heterogenous HEA/HEO catalysts were prepared by thermal reduction of senary HEOs (NiZnCuFeAIZrOx),where exsolvable metals (e.g.,Ni,Zn,Cu) in situ emerged and formed randomly dispersed HEA nanoparticles anchoring on the HEO *** catalyst exhibits excellent catalytic performance:100%conversion of vanillin and 95%selectivity toward high-value 2-methyl-4 methoxy phenol at low temperature of 120℃,which were attributed to the synergistic effect among HEO matrix(with abundant oxygen vacancies),anchored HEA nanoparticles (having excellent hydrogenolysis capability),and their intimate hetero-interfaces(showing strong electron transferring effect).Therefore,our work reported the successful construction of HEA/HEO heterogeneous catalysts and their superior multifunctionality in biomass conversion,which could shed light on catalyst design for many important reactions that are complex and require multifunctional active sites.

关键词： biomass conversion heterogeneous catalysts high-entropy oxide high-entropy alloys lignin pyrolysis