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On-chip ultra-high rejection and narrow bandwidth filter based on coherency-broken cascaded cladding-modulated gratings

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Photonics Research 2024年第5期12卷 979-985页

作者： JINZHAO WANG TING LI yang feng JIEWEN LI WANXIN LI LUWEI DING YONG YAO JIANAN DUAN WEI liu feng HE YI ZOU XIAOCHUAN XU Guangdong Provincial Key Laboratory of Integrated Photonic-Electronic Chip Guangdong Provincial Key Laboratory of Aerospace Communication and Networking TechnologyHarbin Institute of TechnologyShenzhenShenzhen 518055China School of Information Science and Technology ShanghaiTech UniversityShanghai 201210China

Bragg filters are of essential importance for chip-scale photonic systems.However,the implementation of filters with sub-nanometer bandwidth and rejection beyond 70 dB is hindered by the high index contrast of the siliconon-insulator platform,which makes filters prone to fabrication imperfections.In this paper,we propose to combine coherency-broken cascading architecture and cladding modulation to circumvent the intrinsic limitation.The cascading architecture effectively prevents the accumulation of phase errors,while the cladding modulation offers additional design freedom to reduce the coupling coefficient.A bimodal Bragg filter with a testingequipment-limited rejection level of 74 dB and a 40 dB bandwidth of 0.44 nm is experimentally demonstrated.The minimum feature size is 90 nm,which significantly relieves the fabrication constraints.

关键词： filter cladding narrow

Atmospheric chemistry of 2-nitrobenzaldehyde:Initiated by photo-excitation,OH-oxidation,and small TiO_(2) clusters adsorption catalysis

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Journal of Environmental Sciences 2024年第5期139卷 123-137页

作者： feng-yang Bai Xiang-Huan liu Ting-Ting Meng Zhou Yu Yi-Chen Wang Shuang Ni Zhen Zhao Institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang 110034China

The fate of 2-nitrobenzaldehyde(2-NBA)is of interest in atmospheric chemistry as it is a semi-volatile organic compound with high photosensitivity.This study presents a quantum chemical study of the gas-phase reactions of 2-NBA photo-excitation and OH-oxidation in the absence and presence of small TiO_(2) clusters.To further understand the unknown photolysis mechanism,the photo-reaction pathways of ground singlet state and the lying excited triplet state of 2-NBA were investigated including the initial and subsequent reactions of proton transfer,direct CO,NO_(2),and HCO elimination routes in the presence of O_(2) and NO.Meanwhile,the OH-mediated degradation of 2-NBA proceeded via five H-extraction and six OH-addition channels by indirect mechanism,which follows a succession of reaction steps initiated by the formation of weakly stable intermediate complexes.The H-extraction from the-CHO group was the dominant pathway with a negative activation energy of-1.22 kcal/mol.The calculated rate coefficients at 200–600 K were close to the experimental data in literature within 308-352 K,and the kinetic negative temperature independence was found in both experimental literature and computational results.Interestingly,2-NBA was favored to be captured onto small TiO_(2) clusters via six adsorption configurations formed via various combination of three types of bonds of Ti…O,Ti…C,and O…H between the molecularly adsorbed 2-NBA and TiO_(2) clusters.Comparison indicted that the chemisorptions of aldehyde oxygen have largest energies.The results suggested adsorption conformations have a respectable impact on the catalysis barrier.This study is significant for understanding the atmospheric chemistry of 2-nitrobenzaldehyde.

关键词： 2-nitrobenzaldehyde OH radical oxidation Rate coefficient Photolysis mechanism Adsorption catalysis

Interfacial mechanism of hydrogel with controllable thickness for stable drag reduction

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Friction 2024年第2期12卷 231-244页

作者： Xiaotong WU Ying liu Yunlei ZHANG Xingwei WANG Wufang yang Lang JIANG Shuanhong MA Meirong CAI feng ZHOU School of Advanced Manufacturing Nanchang UniversityNanchang 330031China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Yantai Zhongke Research Institute of Advanced Materials and Green Chemical Engineering Shandong Laboratory of Yantai Advanced Materials and Green ManufactureYantai 264006China

Surface wettability plays a significant role in reducing solid–liquid frictional resistance,especially the superhydrophilic/hydrophilic interface because of its excellent thermodynamic stability.In this work,poly(acrylic acid)-poly(acrylamide)(PAA–PAM)hydrogel coatings with different thicknesses were prepared in situ by polydopamine(PDA)-UV assisted surface catalytically initiated radical polymerization.Fluid drag reduction performance of hydrogel surface was measured using a rotational rheometer by the plate–plate mode.The experimental results showed that the average drag reduction of hydrogel surface could reach up to about 56%in Couette flow,which was mainly due to the interfacial polymerization phenomenon that enhanced the ability of hydration layer to delay the momentum dissipation between fluid layers and the diffusion behavior of surface.The proposed drag reduction mechanism of hydrogel surface was expected to shed new light on hydrogel–liquid interface interaction and provide a new way for the development of steady-state drag reduction methods.

关键词： steady state drag reduction hydrogel interface hydration hydrophilic

Plutonium utilization in a small modular molten-salt reactor based on a batch fuel reprocessing scheme

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Nuclear Science and Techniques 2024年第4期35卷 15-28页

作者： Xue-Chao Zhao Rui Yan Gui-feng Zhu Ya-Fen liu Jian Guo Xiang-Zhou Cai yang Zou Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China CAS Innovative Academies in TMSR Energy System Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

A molten salt reactor(MSR)has outstanding features considering the application of thorium fuel,inherent safety,sustainability,and resistance to proliferation.However,fissile material^(233)U is significantly rare at the current stage,thus it is difficult for MSR to achieve a pure thorium-uranium fuel cycle.Therefore,using plutonium or enriched uranium as the initial fuel for MSR is more practical.In this study,we aim to verify the feasibility of a small modular MSR that utilizes plutonium as the starting fuel(SM-MSR-Pu),and highlight its advantages and disadvantages.First,the structural design and fuel management scheme of the SM-MSR-Pu were presented.Second,the neutronic characteristics,such as the graphite-irradiation lifetime,burn-up performance,and coefficient of temperature reactivity were calculated to analyze the physical characteristics of the SM-MSR-Pu.The results indicate that plutonium is a feasible and advantageous starting fuel for a SM-MSR;however,there are certain shortcomings that need to be solved.In a 250 MWth SM-MSR-Pu,approximately 288.64 kg^(233)U of plutonium with a purity of greater than 90% is produced while 978.00 kg is burned every ten years.The temperature reactivity coefficient decreases from -4.0 to -6.5 pcm K^(-1) over the 50-year operating time,which ensures a long-term safe operation.However,the amount of plutonium and accumulation of minor actinides(MAs)would increase as the burn-up time increases,and the annual production and purity of^(233)U will decrease.To achieve an optimal burn-up performance,setting the entire operation time to 30 years is advisable.Regardless,more than 3600 kg of plutonium eventually accumulate in the core.Further research is required to effectively utilize this accumulated plutonium.

关键词： Molten salt fuel Plutonium utilization ^(233)U TRUs mole fraction Temperature feedback coefficient

Construction of Cu-Zn Co-doped layered materials for sodium-ion batteries with high cycle stability

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Chinese Chemical Letters 2024年第5期35卷 441-446页

作者： Xiping Dong Xuan Wang Zhixiu Lu Qinhao Shi Zhengyi yang Xuan Yu Wuliang feng Xingli Zou yang liu Yufeng Zhao Institute for Sustainable Energy&College of Sciences Shanghai UniversityShanghai 200444China Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province Yancheng Institute of TechnologyYancheng 224051China State Key Laboratory of Advanced Special Steel&Shanghai Key Laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

Due to its high operational voltage and energy density,P2-type Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) has become a leading cathode material for sodium-ion batteries(SIBs),which is an ideal option for large-scale energy storage.However,the practical application of P2-type Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) is limited by the capacity constraints and unwanted phase transitions,presenting significant challenges to the widespread application of SIBs.To address these challenges and optimize the electrochemical properties of the P2 phase cathode material,this study proposes a Cu and Zn co-doped strategy to improve the electrochemical performance.The incorporation of Cu/Zn can stabilize the P2-phase structure against P2-O2 phase transitions,thus enhancing its electrochemical properties.The as-obtained P2-type Na0.67[Ni_(0.3)Mn_(0.58)Cu_(0.09)Zn_(0.03)]O_(2) cathode material shows an impressive cycling stability,maintaining 80%capacity retention after 1000 cycles at 2 C.The cyclic voltammetry(CV)tests show that the Cu^(2+)/Cu^(3+)redox reaction is also involved in charge compensation during the charge/discharge process.

关键词： Sodium-ion batteries Cathode material Cycle performance Cu/Zn co-doped P2-type Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2)

In situ reconstruction induced oxygen-deficient multiphase Cu based species hybridized with Ni single atoms as tandem platform for CO_(2) electroreduction

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Nano Research 2024年第5期17卷 3888-3894页

作者： Juzhe liu Yuheng Wang Pengpeng Mo feng yang Kaiqi Jiang Zhixiang Cheng Yuxuan liu Zhiyi Sun Zheng liu Yimei Zhang Wenxing Chen The Key Laboratory of Resources and Environmental System Optimization Ministry of EducationCollege of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China Energy&Catalysis Center School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China SEPA Key Laboratory of Eco-Industry Chinese Research Academy of Environmental SciencesBeijing 100012China

Tandem catalysis,capable of decoupling individual steps,provides a feasible way to build a high-efficiency CO_(2) electro-conversion system for multicarbons(C_(2+)).The construction of electrocatalytic materials is one of focusing issues.Herein,we fabricated a single atom involved multivalent oxide-derived Cu composite material and found it inclined to reconstruct into oxygen-deficient multiphase Cu based species hybridized with monatomic Ni on N doped C matrix.In this prototype,rapid CO generation and C-C coupling are successively achieved on NiN4 sites and surface amorphized Cu species with defects,resembling a micro-production line.In this way,the in situ formed tandem catalyst exhibited a high Faradaic efficiency(FE)of~78%for C_(2+)products along with satisfactory durability over 50 h.Particularly,the reconstruction-induced amorphous layer with abundant asymmetric sites should be favorable to improve the ethanol selectivity(FE:63%),which is about 10 times higher than that of the non-tandem Cu-based contrast material.This work offers a new approach for manipulating tandem catalyst systems towards enhancing C_(2+)products.

关键词： tandem catalysis single atom reconstruction amorphous CO_(2)reduction reaction

Unstructured Road Extraction in UAV Images based on Lightweight Model

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 372-384页

作者： Di Zhang Qichao An Xiaoxue feng Ronghua liu Jun Han feng Pan School of Automation Beijing Institute of TechnologyBeijing 100081China Tianjin Institute of Maritime Navigation Instruments Tianjin 300130China The 716th Research Institute of China Shipbuilding Group Co. LtdJiangsu 222061China

There is no unified planning standard for unstructured roads,and the morphological structures of these roads are complex and varied.It is important to maintain a balance between accuracy and speed for unstructured road extraction models.Unstructured road extraction algorithms based on deep learning have problems such as high model complexity,high computational cost,and the inability to adapt to current edge computing devices.Therefore,it is best to use lightweight network models.Considering the need for lightweight models and the characteristics of unstructured roads with different pattern shapes,such as blocks and strips,a TMB(Triple Multi-Block)feature extraction module is proposed,and the overall structure of the TMBNet network is described.The TMB module was compared with SS-nbt,Non-bottleneck-1D,and other modules via experiments.The feasibility and effectiveness of the TMB module design were proven through experiments and visualizations.The comparison experiment,using multiple convolution kernel categories,proved that the TMB module can improve the segmentation accuracy of the network.The comparison with different semantic segmentation networks demonstrates that the TMBNet network has advantages in terms of unstructured road extraction.

关键词： Unstructured road Lightweight model Triple Multi-Block(TMB) Semantic segmentation net

Structural,^(40)Ar/^(39)Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone:Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 32-49页

作者： feng Yipeng WANG Genhou WANG Shulai LI Dian WANG Huan LU yang liu Han ZHANG Peilie Beijing Institute of Geology for Mineral Resources Co. Ltd.Beijing 100012China School of Earth Sciences and Resources China University of Geosciences(Beijing)Beijing 100083China College of Earth Sciences Chengdu University of TechnologyChengdu 610059China Rock Analysis Laboratory Regional Geology Survey Institute of Hebei ProvinceLangfangHebei 065099China Chengdu Center China Geology SurveyChengdu 610081China

The Jitang metamorphic complex is key to studying the tectonic evolution of the Northern Lancangjiang zone.Through structural-lithological mapping,structural analysis and laboratory testing,the composition of the Jitang metamorphic complex was determined.The macro-and microstructural analyses of the ductile detachment shear zone(Guoxuepu ductile shear zone,2–4 km wide)between the metamorphic complex and the overlying sedimentary cap show that the shear sense of the ductile shear zones is top-to-the-southeast.The presence of various deformation features and quartz C-axis electron backscatter diffraction(EBSD)fabric analysis suggests multiple deformation events occurring at different temperatures.The average stress is 25.68 MPa,with the strain rates(έ)ranging from 9.77×10^(−14)s^(−1)to 6.52×10^(−16)s^(−1).The finite strain of the Guoxuepu ductile shear zone indicates an elongated strain pattern.The average kinematic vorticity of the Guoxuepu ductile shear zone is 0.88,implying that the shear zone is dominated by simple shear.The muscovite selected from the protomylonite samples in the Guoxuepu ductile shear zone yields a 40Ar-39Ar age of 60.09±0.38 Ma.It is suggested that,coeval with the initial Indo–Eurasian collision,the development of strike-slip faults led to a weak and unstable crust,upwelling of lower crust magma,then induced the detachment of the Jitang metamorphic complex in the Eocene.

关键词： ^(40)Ar/^(39)Ar dating strain pattern vorticity EBSD Guoxuepu shear zone Jitang metamorphic complex

Two sandwich-type uranyl-containing polytungstates catalyze aerobic synthesis of benzimidazoles

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Rare Metals 2024年第3期43卷 1316-1322页

作者： Yu-feng liu Qi-Long Hu Xue-Jiao Chen Ke Li Pei Luo Guo-Ping yang School of Chemistry and Material Science Jiangxi Province Key Laboratory of Synthetic ChemistryJiangxi Key Laboratory for Mass Spectrometry and InstrumentationEast China University of TechnologyNanchang330013China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China

Diversified synthetic strategies are extremely important for the structural diversity of uranium-containing polyoxometalates(U-POMs)and their functional expansion.Herein,two sandwich-type U-POMs were reported,which are Na_(5.6)K_(6.4)[(UO_(2))(H_(2)O)(TeW_(9)O_(33))]_(2)·21H_(2)O(UTeW_(9))and Na_(8.9)K_(2.7)H_(1.19)[K_(0.79)(UO_(2))_(2.21)(PW_(9)O_(34))_(2)]·12H_(2)O(UPW_9)using in-situ strategy and lacunary precursor strategy,respectively.UTeW_9 shows a typical Keggin-typeopen or half-sandwich configuration.

关键词： configuration expansion sandwich