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70 Gbps PAM-4850-nm oxide-confined VCSEL without equalization and pre-emphasis

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Journal of Semiconductors 2024年第5期45卷 5-7页

作者： Anjin Liu Bao tang zhiyong Li Wanhua Zheng Key Laboratory of Optoelectronic Materials and Devices Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Accelink technologies co. LtdWuhan 430205China Key Laboratory of Solid-State Optoelectronics Information Technology Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China

Directly modulated 850-nm vertical-cavity surface-emitting lasers(VCSELs)with the advantages of low cost,high modulation speed,good reliability,and low power consumption,are the key sources in the optical interconnects with multimode fibers for the supercomputers,data centers,and machine learning applications[1−3].Typically,non-return-tozero(NRZ)modulation format is used.

关键词： return confined fibers

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Systematic Review on Wearable Lower Extremity Robotic Exoskeletons for Assisted Locomotion

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Journal of Bionic Engineering 2023年第2期20卷 436-469页

作者： Shuang Qiu Zhongcai Pei Chen Wang zhiyong tang School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Lower extremity robotic exoskeletons(LEEX)can not only improve the ability of the human body but also provide healing treatment for people with lower extremity dysfunction.There are a wide range of application needs and development prospects in the military,industry,medical treatment,consumption and other felds,which has aroused widespread concern in society.This paper attempts to review LEEX technical development.First,the history of LEEX is briefy traced.Second,based on existing research,LEEX is classifed according to auxiliary body parts,structural forms,functions and felds,and typical LEEX prototypes and products are introduced.Then,the latest key technologies are analyzed and summarized,and the research contents,such as bionic structure and driving characteristics,human–robot interaction(HRI)and intentawareness,intelligent control strategy,and evaluation method of power-assisted walking efciency,are described in detail.Finally,existing LEEX problems and challenges are analyzed,a future development trend is proposed,and a multidisciplinary development direction of the key technology is provided.

关键词： Lower extremity robotic exoskeletons Bionic robot Classifcation method Human-robot interaction Biomechatronic

Recent advances in metal-organic frameworks for catalytic CO_(2) hydrogenation to diverse products

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Nano Research 2022年第12期15卷 10110-10133页

作者： Shengxian Shao Chengqian Cui zhiyong tang Guodong Li CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing100049China

Selective hydrogenation of CO_(2) to high value-added chemicals,not only gives an effective way to reduce the concentration of CO_(2),but also provides the precursors to advance the industrial manufacturing of chemicals and fuels.With the well-defined reticular frameworks and flexible modifiability,metal-organic frameworks(MOFs)can be the ideal platform to construct the enabled catalysts for CO_(2) hydrogenation,because they have shown the great potential for the enhancement of catalytic activity,the precise control of selectivity,and the excellent stability.In this review,we systematically summarize the recent advances in MOFs based catalysts for CO_(2) hydrogenation towards diverse products.Firstly,synthesis strategies for different kinds of MOFs based catalysts are described.Secondly,selective hydrogenation of CO_(2) towards CO and methane is discussed over various metal nanoparticles/MOFs composites.Thirdly,heterogenization and isolation of molecular catalysts by MOFs are elaborated for producing formic acid.Fourthly,selective hydrogenation of CO_(2) toward methanol is discussed in terms of interface structures of Cu,Zn,and metal nodes of MOFs,the synergy between auxiliary sites and noble metal,and tandem catalytic systems of molecular catalysts and Lewis acid sites.Subsequently,the integration of multiple metal sites,promoters,and cocatalysts into MOFs is described for the selective hydrogenation of CO_(2) to C2+products.After those,the key issue about the stability of MOFs based catalysts for CO_(2) hydrogenation reaction is discussed.Finally,the summary and perspective about MOFs based catalysts for selective CO_(2) hydrogenation and mechanism research are proposed.

关键词： selective CO_(2)hydrogenation metal-organic frameworks(MOFs) noble metal nonnoble metal diverse products mechanism

Recent advances on aerobic photocatalytic methane conversion under mild conditions

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Nano Research 2023年第11期16卷 12558-12571页

作者： Yuheng Jiang Siyang Li Xiaoyu Fan zhiyong tang Chinese Academy of Science(CAS)Key Laboratory of Nanosystem and Hierarchy Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China Center for Nanoscale Science and Technology Academy for Advanced Interdisciplinary StudiesPeking UniversityBeijing 100871China University of Chinese Academy of Sciences Beijing 100049China Sino-Danish College University of Chinese Academy of SciencesBeijing 100049China

Photocatalytic methane conversion to high value-added chemicals under mild conditions acts as a promising approach to utilize natural gas and renewable energy.Specifically,aerobic photocatalytic methane conversion that uses molecular oxygen as oxidant has attracted much attention because it is thermodynamic favorable and could generate various reactive oxygen species,resulting in many value-added products like methanol,formaldehyde,ethane,and ethylene.In this review,we classify the aerobic photocatalytic methane conversion into aerobic photocatalytic partial oxidation of methane(APPOM)and aerobic photocatalytic coupling of methane(APCM).We particularly focus on the fundamentals of oxygen activation and methane reaction modes in these conversions.Finally,we provide a brief summary for current challenges and future prospects towards aerobic photocatalytic methane conversion.

关键词： photocatalysis oxygen methane oxidation coupling mild conditions

Ethanol-derived white emissive carbon dots:The formation process investigation and multi-color/white LEDs preparation

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Nano Research 2022年第2期15卷 942-949页

作者： Boyang Wang Haoqiang Song zhiyong tang Bai Yang Siyu Lu Green Catalysis Center and College of ChemistryZhengzhou UniversityZhengzhou 450001China Henan Institute of Advanced Technology Zhengzhou UniversityZhengzhou 450001China CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China State Key Lab of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China

Carbon dots(CDs)have attracted much attention due to their excellent photoelectric properties and potential applications.Although previous studies have shown that almost all organic molecules can be converted into CDs via chemical carbonization,the mechanism of the conversion process remains unclear.The hydrothermal/solvothermal method commonly used to prepare CDs is complicated and leads to the generation of many by-product CDs with similar structures.Considering that the purification of the synthesized by-products is difficult,the process of CDs formation cannot be readily analyzed and understood.Herein,we use ethanol as a carbon source to synthesize white-emitting CDs(W-CDs).Column chromatography separation shows that the synthesized W-CDs are composed of blue-,cyan-,and yellow-emitting CDs that fluoresce at wavelengths corresponding to the three emission centers of W-CDs.Although the samples have similar graphitic structure,they exhibit different surface states due to variations in the degree of oxidation and carbonization.Therefore,the red-shift in their emission peaks is attributed to an increased degree of carbonization in their polymer structure.Theoretical calculations verify the experimental results,and the prepared CDs are successfully used to develop multi-color and white light-emitting diodes(LEDs).

关键词： carbon dots multi-color-emissive cross-linking fluorescence mechanism phosphors

Highly controlled structured catalysts for on-board methanol reforming

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Journal of Energy Chemistry 2022年第5期31卷 19-26页

作者： Zhuangdian Liang Gang Wang Gaofeng Zeng Jie Zhang zhiyong tang CAS Key Lab of Low-Carbon Conversion Science and Engineering Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China School of Chemistry and Material Science University of Science and Technology of ChinaHefei 230026AnhuiChina School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

The on-board methanol steam reforming(MSR) has long been considered as an effective approach to insitu produce hydrogen for fuel cell vehicles(FCVs). However, the conventional MSR catalyst pellets suffer from easy breakage during the vehicle movement, leading to increased pressure drop and reduced system stability. Herein, we introduce an integrated method to prepare the highly controlled structured catalysts based on coupled processes: direct prototyping the structured substrate using digital light processing(DLP) 3D printing technology, in-situ dynamic crystallization of active components assisted by magnetic resonance imaging(MRI) and calcination. The synthesized catalyst owns a gradient layer of active component, and exhibits better MSR performance, higher mechanical strength, reduced pressure drop, higher Cu dispersion and better adhesion of active compounds when compared with the conventional powder and pellet catalysts. The demonstrated successful application proves the feasibility of developed method,which has great potential to be used for preparing precisely other monolithic catalysts with customized structures.

关键词： Structured catalyst 3D printing Magnetic Resonance Imaging In-situ heterogeneous crystallization Methanol steam reforming

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Progress on the mechanisms of Ru-based electrocatalysts for the oxygen evolution reaction in acidic media

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Journal of Energy Chemistry 2023年第10期85卷 220-238,I0008页

作者： Yuanyuan Shi Han Wu Jiangwei Chang zhiyong tang Siyu Lu Green Catalysis Center and College of ChemistryZhengzhou UniversityZhengzhou 450001HenanChina CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China

Water electrolysis using proton-exchange membranes is one of the most promising technologies for carbon-neutral and sustainable energy production.Generally,the overall efficiency of water splitting is limited by the oxygen evolution reaction(OER).Nevertheless,a trade-off between activity and stability exists for most electrocatalytic materials in strong acids and oxidizing media,and the development of efficient and stable catalytic materials has been an important focus of research.In this view,gaining in-depth insights into the OER system,particularly the interactions between reaction intermediates and active sites,is significantly important.To this end,this review introduces the fundamentals of the OER over Ru-based materials,including the conventional adsorbate evolution mechanism,lattice oxygen oxidation mechanism,and oxide path mechanism.Moreover,the up-to-date progress of representative modifications for improving OER performance is further discussed with reference to specific mechanisms,such as tuning of geometric,electronic structures,incorporation of proton acceptors,and optimization of metal-oxygen covalency.Finally,some valuable insights into the challenges and opportunities for OER electrocatalysts are provided with the aim to promote the development of next-generation catalysts with high activity and excellent stability.

关键词： Oxygen evolution reaction Ru-based electrocatalysts Acidic solutions Mechanism Proton-exchange membranes

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Photocatalytic Methane Conversion:Insight into the Mechanism of C(sp^(3))-H Bond Activation

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CCS Chemistry 2023年第1期5卷 30-54页

作者： Yuheng Jiang Yingying Fan Siyang Li zhiyong tang Chinese Academy of Science(CAS)Key Laboratory of Nanosystem and Hierarchy Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190 Center for Advanced Analytical Science School of Chemistry and Chemical EngineeringSchool of Civil EngineeringAnalytical and Testing CenterGuangzhou UniversityGuangzhou 510006 Center for Nanoscale Science and Technology Academy for Advanced Interdisciplinary StudiesPeking UniversityBeijing 100871 University of Chinese Academy of Sciences Beijing 100049

Mild and direct conversion of methane into high value-added products is a desired goal for chemistry,energy,and environment.The active species generated in the photocatalytic reaction system under mild conditions activate the inert C-H bond in methane and promote methane conversion.This review focuses on the developed mechanisms for C(sp^(3))-H bond activation in photocatalytic methane conversion,including radical and active site mechanisms.Particular emphasis is placed on the detailed summary of mechanism,characterization method,and corresponding application in photocatalytic methane conversion.We also discuss the challenges and prospects for future direction on C(sp^(3))-H bond activation mechanism in photocatalytic methane conversion.This review aims to promote the development of photocatalytic methane conversion and provides guidance for the design of high-efficiency photocatalysts.

关键词： photocatalysis methane C-H bonds radical active site

The activity of Zn precursors determines the cation exchange reaction kinetics with Ag_(2)S:Zn-doped Ag_(2)S or Ag_(2)S@ZnS QDs

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Nano Research 2023年第10期16卷 12315-12322页

作者： zhiyong tang Hongchao Yang Ziqiang Sun Yejun Zhang Guangcun Chen Qiangbin Wang CAS Key Laboratory of Nano-Bio Interface Division of Nanobiomedicine and i-LabSuzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China Nano Science and Technology Institute University of Science and Technology of ChinaHefei 230026China

Cation exchange(CE)has been emerged as a promising post-synthesis strategy of colloidal nanocrystals.However,it is unclear how the cation precursor affects the CE process and the final colloidal nanocrystals.Herein,we utilized two Zn-B Lewis acidbase adduct complexes(B=oleylamine(OAM)and methanol(MeOH))as Zn precursors for CE with Ag_(2)S quantum dots(QDs).Our study revealed that the steric hindrance and complexing capabilities of Zn precursor significantly affect the CE kinetics.As a result,the Zn-doped Ag_(2)S(Zn:Ag_(2)S)and Ag_(2)S@ZnS core–shell QDs were successfully obtained with enormous enhancement of their photoluminescence(PL)intensities.Theoretical simulation showed that the Zn-OAM with higher desolvation energy and spatial hindrance tended to form doped Zn:Ag_(2)S QDs due to the inefficient cation exchange.Whereas the Zn-MeOH with lower exchange barrier promoted the conversion of Ag-S to Zn-S,thus forming Ag_(2)S@ZnS core–shell QDs.We anticipate that this finding will enrich the regulatory approaches of post-synthesis of colloidal nanocrystals with desirable properties.

关键词： cation exchange Ag_(2)S quantum dots phase structure desolvation coordination