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Alliance of atomic-scale/nanoscale Fe/Co active sites with hierarchically porous N-doped carbon frameworks for efficient electrocatalytic oxygen reduction

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Rare Metals 2023年第11期42卷 3766-3779页

作者： Hai-Hua yang xiao-Rong Qian Na Zhang xia-Ting Jia Zhi-Yan Wen xiao-Bo Chen Min-Jie Zhou Key Laboratory of Hunan Province for Advanced Carbon-Based Functional Materials Hunan Institute of Science and TechnologyYueyang414006China School of Chemistry and Chemical Engineering Hunan Institute of Science and TechnologyYueyang414006China School of Physics and Electronic Science Hunan Institute of Science and TechnologyYueyang414006China Department of Chemistry University of Missouri-Kansas CityKansas City64111USA

Ingenious establishment of transition metal-nitrogen-carbon electrocatalysts with diverse catalytic active sites and hierarchically porous frameworks is highly significant to boost the oxygen reduction reaction(ORR)in Zn-air batteries(ZABs).In this study,Fe/Co co-doped zeolitic imidazolium frameworks(ZIFs)and graphitic carbon nitride(g-C_(3)N_(4))were integrated and pyrolyzed to construct carbon-based electrocatalysts containing Fe,Co and N elements(labelled as Co-CoFe@NRPC),in which atomic-sc ale FeN_x and CoN_x,and nano scale metallic Co and CoFe alloy moieties were aligned with hierarchically porous N-doped carbon frameworks constructed by interconnected micropolyhedrons,nano tubes and *** diverse active moieties guaranteed excellent intrinsic catalytic activity,while the hierarchically porous N-doped carbon frameworks ensured admirable accessibility of the catalytic active sites,excellent electrical conductivity,satisfactory mass transport and good ***,the optimized Co-CoFe@NRPC-90(with 90 mg g-C_(3)N_(4) added)electrocatalyst exhibited excellent ORR performance with a high half-wave potential of 885 mV(*** hydrogen electrode(RHE)),diffusion-limiting current density of 6.15 mA·cm^(-2),desirable durability and methanol ***,the liquid ZAB established with Co-CoFe@NRPC-90 as an air-cathode electrocatalyst manifested an outstanding power density(281 mW·cm^(-2))and specific capacity(820.9 mAh·g_(Zn)^(-1)),transcending the liquid ZAB based on a commercial Pt/C electrocatalyst.

关键词： Fe/Co co-doped zeolitic imidazolium frameworks Graphitic carbon nitride Transition metal-nitrogen-carbon electrocatalyst Oxygen reduction reaction(ORR)

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Surface roughness modulated resistivity in copper thin films

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Science China(Physics,Mechanics & Astronomy) 2018年第10期61卷 70-77页

作者： HongKang Song Ke xia Jiang xiao Department of Physics Beijing Normal University Beijing 100875 China Department of Physics and State Key Laboratory of Surface Physics Fudan University Shanghai 200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093 China

The surfaces of metallic thin films are never flat. The resistivity in thin films is very different from that in bulk because of the unavoidable rough surfaces. In this study, we apply a quantum-mechanical method to study the resistivity in metallic thin *** resulting resistivity formula for metallic thin films merely involves two parameters: bulk relaxation time and surface roughness. We use the formula to fit a large number of experimental data sets for copper thin films obtained using different growing methods. With an additional tuning parameter for calibrating the film thickness, the quantum formula can provide a universal fitting to most data with a satisfactory precision, regardless of their growing methods or data source.

关键词： thin film thickness dependent resistivity surface roughness

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Kinetics study of aqueous sorption of phenanthrene to humic acids and sediments

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Journal of Environmental Sciences 2004年第3期16卷 408-413页

作者： ZHOUYan-mei LIURui-xia TANGHong-xiao StateKeyLaboratoryofEnvironmentalAquaticChemistry ResearchCenterforEco-EnvironmentalSciencesChineseAcademyofSciencesBeijing100085China

The sorption behavior was determined for a model polycyclic aromatic hydrocarbon(PAH), i.e., phenanthrene(PHN), from water to three humic acids(HAs) and three sediments in different reacting time. The chemical compositions of HA samples were measured using cross polarization magic angle spinning carbon 13(CPMAS 13 C NMR along with elemental analysis. The dissolved humic substances dissociating from solid HAs and sediments were characterized by 1 H NMR. The experiments indicated that the sorption modes and mechanisms of natural sorbents for PHN varied significantly between short(<7 d) and long contact time and the reaction time should be taken into consideration in studying the overall sorption process. The sorption capacity( K ′ f) and exponent( n ) might be relative to the properties of dissolved humic materials in initial stage but the solid aromatic organic matter after long time reaction. According to the experiments performed in this investigation and the previous researches, a conceptive sorption model was established.

关键词： sorption phenanthrene humic acid sediment CPMAS 13 C NMR

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Rate efect and coupled evolution of atomic motions and potential landscapes

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Acta Mechanica Sinica 2013年第5期29卷 676-681页

作者： Pan xiao Jun Wang Rong yang Fu-Jiu Ke Meng-Fen xia Yi-Long Bai State Key Laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences School of Physics and Nuclear Energy Engineering Beihang University

Since rate effect of materials plays a key role in impact engineering, the microscopic mechanism of rate effect is investigated at molecular level in this paper. The results show that rate effect on the strength of atomic system is closely related to the coupled evolution of atomic motions and potential landscapes. Accordingly, it becomes possible to develop a new algorithm of molecular simulation, which could properly and efficiently demonstrate strain rate effect under a wide range of loading rates and unveil the mecha- nisms underlying the strain rate effects.

关键词： Strain rate effect Atomic motions - Potential landscape Molecular simulation

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Fine motor skill training enhances functional plasticity of the corticospinal tract after spinal cord injury

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Neural Regeneration Research 2016年第12期11卷 1990-1996页

作者： Jian Liu xiao-yu yang Wei-wei xia Jian Dong Mao-guang yang Jian-hang Jiao Department of Orthopedics China-Japan Union HospitalJilin University

Following central nervous system injury, axonal sprouts form distal to the injury site and extend into the denervated area, reconstructing neural circuits through neural plasticity. How to facilitate this plasticity has become the key to the success of central nervous system repair. It remains controversial whether fine motor skill training contributes to the recovery of neurological function after spinal cord injury. Therefore, we established a rat model of unilateral corticospinal tract injury using a pyramidal tract cutting method. Horizontal ladder crawling and food ball grasping training procedures were conducted 2 weeks before injury and 3 days after injury. The neurological function of rat forelimbs was assessed at 1, 2, 3, 4, and 6 weeks after injury. Axon growth was observed with biotinylated dextran amine anterograde tracing in the healthy corticospinal tract of the denervated area at different time periods. Our results demonstrate that compared with untrained rats, functional recovery was better in the forelimbs and forepaws of trained rats. The number of axons and the expression of growth associated protein 43 were increased at the injury site 3 weeks after corticospinal tract injury. These findings confirm that fine motor skill training promotes central nervous system plasticity in spinal cord injury rats.

关键词： nerve regeneration spinal cord injury plasticity axons functional training corticospinal tract growth associated protein 43 neural regeneration

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Derivation of a second-order model for Reynolds stress using renormalization group analysis and the two-scale expansion technique

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Acta Mechanica Sinica 2011年第5期27卷 649-659页

作者： xiao-Hong Wang Zheng-Feng Liu xiao-xia Lu Department of Thermal Science and Energy Engineering University of Science and Technology of China230026 Hefei China

With the two-scale expansion technique proposed by Yoshizawa,the turbulent fluctuating field is expanded around the isotropic *** a low-order two-scale expansion,applying the mode coupling approximation in the Yakhot-Orszag renormalization group method to analyze the fluctuating field,the Reynolds-average terms in the Reynolds stress transport equation,such as the convective term,the pressure-gradient-velocity correlation term and the dissipation term,are *** numerical examples：turbulent flow past a backward-facing step and the fully developed flow in a rotating channel,are presented for testing the efficiency of the proposed second-order *** these two numerical examples,the proposed model performs as well as the Gibson-Launder （GL） model,giving better prediction than the standard k-ε model,especially in the abilities to calculate the secondary flow in the backward-facing step flow and to capture the asymmetric turbulent structure caused by frame rotation.

关键词： Turbulent modeling Renormalization group Two-scale expansion Reynolds stress transport equation Second-order model

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Managing Procurement and Production Outsourcing under Dynamic Prices

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Acta Mathematicae Applicatae Sinica 2013年第1期29卷 135-142页

作者： xiao-gang CAO Chao yang Hui WEN Huo-song xia Ji-zi LI School of Management Huazhong University of Science and Technology School of Management Wuhan Textile University School of Science Hubei University of Technology

This paper proposes a procurement and production outsourcing model subject to a dynamic prices environment. Using the optimal control theory we obtain the necessary conditions of the optimal procurement and production policy. From the study of optimal control conditions, we derive qualitative properties of the optimal procurement and production decisions for a few exemplifying cases. Through these results we are able to provide some managerial implications for managers to make real decisions.

关键词： production planning dynamic prices optimal control production outsourcing

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Gene editing:A new step and a new direction toward finding a cure for Duchenne muscular dystrophy(DMD)

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Genes & Diseases 2016年第2期3卷 101-102页

作者： Jim Hu Emily xia Leo yang xiao xiao Department of Laboratory Medicine and Pathobiology The Hospital for Sick ChildrenUniversity of TorontoTorontoOntario M5G 0A4Canada Division of Molecular Pharmaceutics Eshelman School of PharmacyUniversity of North Carolina at Chapel HillChapel HillNC 27599USA

Duchenne muscular dystrophy(DMD)is a progressive muscle degenerative disease affecting one out of 3500 male *** usually succumb to the disease by age *** has been shown that skipping exons of the DMD gene that contain disease-causing mutations from the pre-mRNA can result in a shortened,but functional,dystrophin protein that could bring clinical benefits to patients.A recent breakthrough has been reported in Science by three groups who demonstrated that genetically deleting exon 23 by gene editing can restore the expression of dystrophin(albeit a shortened version)and improve the muscle function in a mouse model of DMD.

关键词： Adeno-associated virus Exon skipping Gene delivery Gene editing Muscular dystrophy

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The key role of inoculated sludge in fast start-up of sequencing batch reactor for the domestication of aerobic granular sludge

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Journal of Environmental Sciences 2019年第4期31卷 127-136页

作者： xiao-chun Wang Zhong-lin Chen Jing Kang xia Zhao Ji-min Shen Liu yang State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of Technology College of Petrochemical Technology Lanzhou University of Technology

Two types of inoculated sludges, granular sludge that had been stored at-20°C and activated sludge, were investigated for the domestication of aerobic granular sludges(AGSs in sequencing batch reactors(SBRs). The results showed that using the stored granular sludge as inoculation sludge could effectively shorten the domestication time of AGS and yielded mature granular sludge after 22 days of operation. The AGS domesticated by stored granular sludge had better biomass and sedimentation properties; its MLSS and SVI reached8.55 g/L and 35.27 mL/g, respectively. The removal efficiencies for chemical oxygen demand(COD), ammonium nitrogen(NH_4^+-N) and total phosphorus(TP) reached 90.76%, 97.39% and 96.40%, respectively. By contrast, 54 days were needed to obtain mature granules using activated sludge. The microbial community structure was probed by using scanning electron microscopy(SEM) and high-throughput sequencing. The results showed that the diversity of the microbial community in mature granules was reduced when stored granular sludge rather than activated sludge was employed as inoculation sludge, and the dominant microbes were changed. The dominant species in mature granules domesticated using stored granular sludge were Zoogloea, Acidovorax and Tolumonas at the genus classification level, while the dominant species were Zoogloea and TM7-genera in granules developed from activated sludge.

关键词： Aerobic granular sludge Microbial community Sequencing batch reactor Stored granular sludge

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Unraveling the catalytically active phase of carbon dioxide hydrogenation to methanol on Zn/Cu alloy: Single atom versus small cluster

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Journal of Energy Chemistry 2021年第10期30卷 582-593,I0015页

作者： xiao-Kuan Wu Hui-Min Yan Wei Zhang Jie Zhang Guang-Jie xia yang-Gang Wang Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry Southern University of Science and TechnologyShenzhen 518055GuangdongChina State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China

Methanol synthesis from CO_(2)hydrogenation catalyzed by Zn/Cu alloy has been widely studied,but there is still debate on its catalytic active phase and whether the Zn can be oxidized during the reaction *** is more,as Zn atoms could locate on Zn/Cu alloy surface in forms of both single atom and cluster,how Zn surface distribution affects catalytic activity is still not *** this work,we performed a systematic theoretical study to compare the mechanistic natures and catalytic pathways between Zn single atom and small cluster on catalyst surface,where the surface oxidation was shown to play the critical *** surface oxidation,the Zn single atom/Cu is more active than the Zn small cluster/Cu,but its surface oxidation is difficult to take ***,after the easy surface oxidation by CO_(2)decomposition,the oxidized Zn small cluster/Cu becomes much more active,which even exceeds the hardlyoxidized Zn single atom/Cu to become the active *** analyses show this dramatic promotion of surface oxidation can be ascribed to the following factors:i)The O from surface oxidation could preferably occupy the strongest binding sites on the center of Zn *** makes the O intermediates bind at the Zn/Cu interface,preventing their too tight binding for further hydrogenation;ii)The higher positive charge and work function on the oxidized surface could also promote the hydrogenation of O *** work provided one more example that under certain condition,the metal cluster can be more active than the single atom in heterogeneous catalysis.

关键词： CO_(2)hydrogenation Surface oxidation Zn/Cu alloy Catalytically active phase

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