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Scalable synthesis of multi-shelled hollow N-doped carbon nanosheet arrays with confined Co/CoP heterostructures from MOFs for pH-universal hydrogen evolution reaction

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science china Chemistry 2022年第3期65卷 619-629页

作者： Zhiqiao Wang Kui Shen Liyu Chen Yingwei Li Key Laboratory of Fuel Cell Technology of Guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China State Key Laboratory of Pulp and Paper Engineering School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China

Developing low-cost but efficient hydrogen evolution reaction(HER)electrocatalysts over whole pH values is a significant but daunting task for the large-scale application of electrochemical hydrogen ***,we develop,for the first time,a scalable MOF-assisted strategy for the fabrication and microstructural optimization of multi-shelled hollow N-doped carbon nanosheet arrays with confined Co/CoP heterostructures on carbon cloth(Co/CoP@NC/CC)for boosting HER *** key to this strategy is the step-by-step epitaxial growth of unprecedented multilayer ZIF-L arrays on carbon cloth,which are subsequently pyrolyzed and controllably phosphorized to achieve the precise control over the shell number and nanoarchitectures of the Co/CoP@NC/***,the HER performances can be significantly enhanced by increasing hollow shell number,and the optimal triple-shelled hollow Co/CoP@NC/CC exhibits low overpotentials of 86,78 and 145 mV in acidic,alkaline and neutral media to deliver a current density of 10 mA cm^(-2),respectively,ranking as one of the best Co-based HER electrocatalysts over whole pH *** DFT calculations suggest that the Co/CoP heterostructures can effectively boost the cleavage of H–OH to generate protons and optimize the adsorption energy of hydrogen(ΔG_(H*)),which,together with the large electrode/electrolyte interface and accelerated charge/mass transfer of multi-shelled hollow array structure as well as the good conductivity and dispersity,are responsible for the remarkably improved HER *** study not only provides a new toolbox for enriching the family of multi-shelled nanoarchitecture materials,but also points out a general and effective route to develop highly efficient self-supported electrode materials for energy-related applications and beyond.

关键词： multi-shelled hollow arrays metal-organic frameworks multilayer ZIF-L arrays Co/CoP heterostructures hydrogen evolution reaction

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Cuckoo search with varied scaling factor

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Frontiers of Computer science 2015年第4期9卷 623-635页

作者： Lijin WANG Yilong YIN Yiwen ZHONG School of Computer science and Technology Shandong University Jinan 250101 China College of Computer and Information science Fujian Agriculture and Forestry University Fuzhou 350002 China School of Computer science and Technology Shandong University of Finance and Economics Jinan 250014 China

Cuckoo search （CS）, inspired by the obligate brood parasitic behavior of some cuckoo species, iteratively uses L6vy flights random walk （LFRW） and biased/selective random walk （BSRW） to search for new solutions. In this study, we seek a simple strategy to set the scaling factor in LFRW, which can vary the scaling factor to achieve better performance. However, choosing the best scaling factor for each problem is intractable. Thus, we propose a varied scal- ing factor （VSF） strategy that samples a value from the range [0,1] uniformly at random for each iteration. In addition, we integrate the VSF strategy into several advanced CS vari- ants. Extensive experiments are conducted on three groups of benchmark functions including 18 common test functions, 25 functions proposed in CEC 2005, and 28 functions intro- duced in CEC 2013. Experimental results demonstrate the ef- fectiveness of the VSF strategy.

关键词： cuckoo search algorithm uniform distribution,random sampling scaling factor function optimization prob-lems

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Graphdiyne Oxide Modified NiO_(x) for Enhanced Charge Extraction in Inverted Planar MAPbI_(3) Perovskite Solar Cells

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Chemical Research in Chinese Universities 2021年第6期37卷 1309-1316页

作者： TANG Jin ZHAO Min CAI Xu LIU Le LI Xiaofang JIU Tonggang science Center for Material Creation and Energy Conversion Institute of Frontier and Interdisciplinary ScienceShandong UniversityQingdao266237P.R.China Key Laboratory of Theoretical Organic Chemistry and Functional Molecules Ministry of EducationSchool of Chemistry and Chemical EngineeringHunan University of Science and TechnologyXiangtan411201P.R.China

The interface defects and nickel vacancies of the NiO_(x)lead to interface charge recombination,which limits its application in perovskite solar ***,graphdiyne oxide(GDYO)was added to NiO_(x)as an inorganic hole transporting *** is found that the average carrier lifetime declined from 29.2 ns to 5.4 ns and the recombination resistance increased significantly after the GDYO adding determined by the time-resolved photoluminescence and electrochemical impedance spectroscopy *** further demonstrated that the GDYO adding to NiO_(x)effectively improved the charge extraction,accelerated the charge transportation and suppressed the charge ***,the optimized NiO_(x)(GDYO)-based cell showed superior performance with a higher fill factor(81.99%)and improved stability with respect to the reference *** method provides a new method for property regulation of NiO_(x)in inverted planar MAPbI_(3) perovskite solar cells.

关键词： Graphdiyne oxide Nickel oxide MAPbI_(3)perovskite solar cell Charge extraction

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In-situ structure reconstitution of NiCo2Px for enhanced electrochemical water oxidation

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science Bulletin 2017年第22期62卷 1510-1518页

作者： Xue Bai Zhiyu Ren Shichao Du Huiyuan Meng Jun Wu Yuzhu Xue Xiaojun Zhao Honggang Fu Tianjin Key Laboratory of Structure and Performance for Functional Molecules Key Laboratory of Inorganic-Organic Hybrid Functional Material Chemistry Ministry of Education of the People's Republic of China Tianjin Normal University Tianjin 300387 China Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education of the People's Republic of China School of Chemistry and Materials Science Heilongjiang University Harbin 150080 China

Gaining insight into the structure evolution of transition-metal phosphides during anodic oxidation is significant to understand their oxygen evolution reaction(OER) mechanism, and then design highefficiency transition metal-based catalysts. Herein, NiCo_2P_x nanowires(NWs) vertically grown on Ni foam were adopted as the target to explore the in-situ morphology and chemical component reconstitution during the anodic oxidation. The major factors causing the transformation from NiCo_2P_x into the hierarchical NiCo_2P_x@CoNi(OOH)_x NWs are two competing reactions: the dissolution of NiCo_2P_x NWs and the oxidative re-deposition of dissolved Co^(2+) and Ni^(2+) ions, which is based primarily on the anodic bias applied on NiCo2 Px NWs. The well balance of above competing reactions, and local pH on the surface of NiCo_2P_x NW modulated by the anodic oxidation can serve to control the anodic electrodeposition and rearrangement of metal ions on the surface of NiCo_2P_x NWs, and the immediate conversion into CoNi(OOH)_x. Consequently, the regular hexagonal CoNi(OOH)_x nanosheets grew around NiCo_2P_x *** from the active catalytic sites on the surface and the sufficient conductivity, the resultant NiCo_2P_x@CoNi(OOH)_x arrays also display good OER activity, in terms of the fast kinetics process, the high energy conversion efficiency, especially the excellent durability. The strategy of in-situ structure reconstitution by electrochemical reaction described here offers a reliable and valid way to construct the highly active systems for various electrocatalytic applications.

关键词： NiCo2Px Structure reconstitution Anodic oxidation CoNi(OOH)x Oxygen evolution reaction(OER)

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Dual-functional photocatalysis boosted by electrostatic assembly of porphyrinic metal-organic framework heterojunction composites with CdS quantum dots

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Chinese Chemical Letters 2023年第9期34卷 165-170页

作者： Zhiyao Chen Sihong Li Qijie Mo Li Zhang Cheng-Yong Su MOE Laboratory of Bioinorganic and Synthetic Chemistry Lehn Institute of Functional MaterialsSchool of ChemistrySun Yat-sen UniversityGuangzhou 510006China

Photocatalytic dual-functional reaction under visible light irradiation represents a sustainable development *** detail,H2production coupled with benzylamine oxidation can remarkably lower the cost by replacing sacrificial *** this work,Cd S quantum dots(Cd S QDs)were successfully loaded onto the surface of a porphyrinic metal-organic framework(Pd-PCN-222)by the electrostatic selfassembly at room *** consequent Pd-PCN-222/CdS heterojunction composites displayed superb photocatalytic activity under visible light irradiation,achieving a H2production and benzylamine oxidation rate of 5069 and 3717μmol g^(-1)h^(-1)with>99%selectivity in 3 *** is no noticeable loss of catalytic capability during three successive *** studies by in situ electron spin resonance and X-ray photoelectron spectroscopy disclosed that CdS QDs injected photoexcited electrons to Pd-PCN-222 and then Zr6clusters under visible-light irradiation,and thus Cd S QDs and Zr6clusters behave as the photocatalytic oxidation and reduction centers,respectively.

关键词： Metal-organic framework composites Electrostatic self-assembly Dual-functional photocatalysis CdS quantum dots Metalloporphyrin

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Overview and Development of Variable Frequency AC Generators for More Electric Aircraft Generation System

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Chinese Journal of Electrical Engineering 2017年第2期3卷 32-40页

作者： Zhuoran Zhang Jincai Li Ye Liu Yanwu Xu Yangguang Yan Center for More-Electric-Aircraft Power Systems Nanjing University of Aeronautics and Astronautics Nanjing211106China

With the development of more electric aircraft(MEA),higher demands for electrical energy are put forward in generation *** to constant frequency AC(CFAC)generation systems,the constant speed drive(CSD)is eliminated and integrated starter/generator(SG)can be realized in variable frequency AC(VFAC)generation *** this paper,an overview of VFAC generators for safety-critical aircraft applications is presented,with a particular focus on the key features and requirements of candidate generators and the starting control *** rotor synchronous machines(WRSMs)are typical generators used in VFAC generation systems so ***,hybrid excitation synchronous machines(HESMs)and cage-type induction machines are promising candidates for VFAC generation *** generation operation of WRSM is relatively mature,however,the SG technology of WRSM is still full of *** one of the most important issues,the starting excitation methods of WRSM are *** HESM-based VFAC SG system is proposed and developed in this *** experimental results show that the starting mode,transition mode and generating mode of the VFAC SG system are *** continuous progress of VFAC generation system makes great contributions to the realization of MEA.

关键词： Brushless starter/generator generation system hybrid excitation synchronous machine more electric aircraft variable frequency AC generator wound rotor synchronous machine

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Near-infrared and Multicolor Electrochromic Device Based on Polyaniline Derivative

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Chinese Journal of Polymer science 2014年第8期32卷 1040-1051页

作者： Zhong-qiu Tong Hai-ming Lv Jiu-peng Zhao 李垚 Center for Composite Materials and Structure Harbin Institute of Technology School of Chemical Engineering and Technology Harbin Institute of Technology

Electroactive conducting copolymers of aniline （ANI） and diphenylamine （DPA） are prepared on indium tin oxide （ITO） surface from 1 mol/L H2SO4 aqueous solution with different feed ratios of ANI to DPA by using a potentiostatic method. FTIR spectra and SEM measurements are used to confirm the formation of copolymers. Due to the combination of the N,N＇-diphenyl benzidine and aniline units in the molecular chain, the copolymer films exhibit improved electrochemical and electrochromic properties, compared to PANI and PDPA. The copolymer [marked as P（ANI9-co-DPA1）] film prepared at a ratio of 9：1 （ANI/DPA） exhibits novel transmittance modulation both in visible and near-infrared （NIR） region between -0.8 V and 0.8 V （52% and 67% respectively） and fast response time （3.6 s for coloration and 2.3 s for bleaching at 600 nm）. An electrochromic device （ECD） based on P（ANI9-co-DPA1） and PEDOT：PSS is also fabricated and shows a multicolor electrochromic performance, with a good optical contrast （29% in visible region and 40% in NIR region）, acceptable response time （8.3 s for coloration and 7.5 s for bleaching at 600 nm） and long-term stability. Clear color changes from transparent （-0.8 V）, bright green （0 V）, seagreen （0.4 V） to dark slate gray （0.8 V） are demonstrated.

关键词： Conjugated polymer Spectroelectrochemistry Electrochromic device Polyaniline.

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Microstructure and mechanical properties of SiC_(f)/SiBCN ceramic matrix composites

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Journal of Advanced Ceramics 2015年第1期4卷 31-38页

作者： Jiaying WANG Zhihua YANG Xiaoming DUAN Dechang JIA Yu ZHOU Institute for Advanced Ceramics Harbin Institute of TechnologyHarbin 150080Chin

SiC fiber reinforced SiBCN ceramic matrix composites(CMCs)have been prepared by mechanical alloying and consolidated by hot *** the sintering process,amorphous SiC fibers crystallized seriously and transformed ***,the interfacial carbothermal reactions caused the strong bonding between the matrix and *** a result,SiCf/SiBCN fractured in a typical catastrophic ***-temperature mechanical properties reached the maximums for the CMC samples sintered at 1900℃/60 MPa/30 *** density,flexural strength,young’s modulus and fracture toughness are 2.56±0.02 g/cm^(3),284.3±17.9 MPa,183.5±11.1 GPa and 2.78±0.14 MPa·m^(1/2),respectively.

关键词： hot pressing composites mechanical properties fiber

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Low Temperature H_(2) Production from Formic Acid Aqueous Solution Catalyzed on Metal Doped Mo_(2)C

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Journal of Renewable Materials 2020年第8期8卷 939-946页

作者： Shuaishuai Zhu Zhigang Pan Yaqiu Tao Yue Chen College of Materials science and Engineering Nanjing Tech UniversityNanjingChina State Key Laboratory of Materials-Oriented Chemical Engineering Nanjing21009China

Hydrogen is recognized as a promising energy scours in the close *** hydrogen preparation from formic acid under mild reaction conditions causes extensive ***_(2)C and metal(Fe,Ni,Co,K)doped Mo_(2)C on granular activated carbon(GAC)were prepared and used as heterogeneous catalysts for H2 generation from formic acid on a fixed bed reactor at 100–250°*** formic acid conversions on doped Mo_(2)C-Me/GAC are clearly improved,especially at lower reaction *** doping presents outstanding effect on H2 selectivity and conversion rate compared to Ni and Fe.A 56.3%formic acid conversion was reached on Mo_(2)C-Co/GAC at 100°C,which triples that on Mo_(2)C/GAC at the same *** 150°C,a high formic acid conversion over 90%was reached on Mo_(2)C-Co/*** long lifetime catalysts with no precious metal provide a low cost route to hydrogen production from formic acid.

关键词： Hydrogen production energy storage and conversion Mo_(2)C/GAC metal doping formic acid decomposition carbon materials

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Enhancing Telco Service Quality with Big Data Enabled Churn Analysis： Infrastructure, Model, and Deployment

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Journal of Computer science & Technology 2015年第6期30卷 1201-1214页

作者：李慧吴迪李高翔柯毅豪刘文杰郑元欢林小拉 Department of Computer science Sun Yat-sen University Guangzhou 510006 China

The penetration of mobile phones is nearly saturated in both developing and developed regions. In such a circumstance, how to prevent subscriber churn has become an important issue for today＇s telecom operators, as the cost to acquire a new subscriber is much higher than that to retain an existing subscriber. In this paper, we propose to leverage the power of big data to mitigate the problem of subscriber churn and enhance the service quality of telecom operators. As the information hub, telecom operators have accumulated a huge volume of valuable data on subscriber behaviors, service usage, and network operations. To enable efficient big data processing, we first build a dedicated distributed cloud infrastructure that integrates both online and offline processing capabilities. Second, we develop a complete churn analysis model based on deep data mining techniques, and utilize inter-subscriber influence to improve prediction accuracy. Finally, we use real datasets obtained from a large telecom operator in china to verify the accuracy of our churn analysis models. The dataset contains the information of over 3.5 million subscribers, which generate over 600 million call detail records （CDRs） per month. The empirical results demonstrate that our proposed method can achieve around 90% accuracy for T ＋ 1 testing periods and identify subscribers with high negative influence successfully.

关键词： subscriber churn big data cloud infrastructure telco service quality

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