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Chinese Journal of Chemical Engineering 2023年第9期61卷 24-36页

作者： Haoyu Yao Jiangcheng li Jiangyan li Xiangfeng liang Gang Wang Haiyan Luo Environmental Resources Green Chemical Separation GroupQingdao Institute of BioenergyBioprocess TechnologyChinese Academy of SciencesQingdao 266101China Beijing Insight Chemistry Co. LtdBeijing 101121China Merck Sharp&Dohme Research and Development(China)Co. LtdBeijing 100101China Institute for Catalysis Hokkaido UniversityN-21W-10Sapporo 001-0021Japan CAS Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China

Polyoxymethylene dimethyl ethers(OMEs)with physical properties similar to those of diesel has received significant attention as green additives for soot emission ***,series of SO_(4)^(2-)/ZrO_(2)-TiO_(2)catalysts were developed for OMEs production from dimethoxymethane(DMM)and1,3,5-trioxane through sequential formaldehyde monomer insertion into C-O bond of *** Lewis but Bronsted acid sites were identified to be active for the decomposition of 1,3,5-trioxane into formaldehyde unit,however,both of them are effective for the chain propagation of DMM via formaldehyde unit insertion into C-O *** studies indicated each chain growth step exhibited the same parameters and activation barrier on corresponding Bronsted and Lewis acid sites due to the same reaction mechanism and very similar chemical structure of ***,the catalytic stability investigation suggested the deactivation behavior was derived from the carbon deposition,and the decay factor could be exponentially correlated with the amount of coke accumulation.

关键词： Polyoxymethylene dimethylethers SO_(4)^(2-)/ZrO_(2)-TiO_(2) Chain propagation Kinetics Deactivation behavior

Simultaneously improving strength and ductility through laminate structure design in Mg–8.0Gd–3.0Y-0.5Zr alloys

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Journal of Materials Science & Technology 2021年第12期71卷 195-200页

作者： Jing li Mengjie Zhao li Jin Fenghua Wang Shuai Dong Jie Dong National Engineering Research Center of light Alloy Net Forming&State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China

The laminate structure was applied to improve the mechanical properties of Mg-8.0 Gd-3.0 Y-0.5 Zr *** types of laminate structures only with different distribution positions of fine grains were produced by friction-stir *** show that the trilayer structure sample exhibits an excellent strengthductility synergy compared to the homogenous structure and bilayer *** enhanced mechanical properties are resulted from the hetero-deformation induced(HDI)stress strengthening and strain hardening which would be enhanced by increasing the quantity of *** observations suggest a crucial role of the number of interfaces in designing the laminate structure.

关键词： Friction-stir processing Mg-Gd-Y-Zr alloy Laminate structure Interface Strength-ductility synergy

Diverse terahertz wavefront manipulations empowered by the spatially interleaved metasurfaces

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Science China(Information Sciences) 2023年第3期66卷 230-238页

作者： Jitao li Zhen YUE Jie li Chenglong ZHENG Silei WANG Mengyao li Yating ZHANG Yan ZHANG Jianquan YAO School of Precision Instruments and Opto-Electronics Engineering Tianjin University College of Optoelectronic Engineering Chengdu University of Information Technology Department of Physics Capital Normal University

Optical metasurfaces have advanced approaches for manipulating light information in the spatial domain, in which the spatially interleaved metasurfaces demonstrate the ability to manipulate a more complex wavefront of light than metasurfaces without the spatial interleaving. The potential of the spatially interleaved metasurfaces has not been fully exploited. In this paper, we design the spatially interleaved terahertz(THz) metasurfaces based on the ingenious spatial interleaving principles to develop the diverse THz wavefront manipulations. Four functions are performed, including the orbital angular momentum(OAM)superposition of single-frequency vortex beams, the separate vortex focusing of single-frequency dual beams,the different OAM manipulations of bifrequency beams in different planes, and achromatic focusing. The demonstrated functions prove that the spatially interleaved metasurface can manipulate THz wavefront at both single frequency and bifrequency, which traditional metasurfaces cannot. This work paves the way for diverse THz wavefront manipulations.

关键词： terahertz wavefront manipulations metasurfaces spatial interleaving onformation optics

Dual context prior and refined prediction for semantic segmentation

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Geo-Spatial Information Science 2021年第2期24卷 228-240,I0004页

作者： Long Chen Jiajie liu Han li Wujing Zhan Baoding Zhou Qingquan li School of Data and Computer Science Sun Yat-sen UniversityGuangzhouChina Guangdong Key Laboratory of Urban Informatics Shenzhen UniversityShenzhenChina Guangdong Laboratory of Artificial Intelligence and Digital Economy(SZ) Shenzhen UniversityShenzhenChina Civil and Transportation Engineering Shenzhen UniversityShenzhenChina

Recently,the focus of semantic segmentation research has shifted to the aggregation of context prior and refined boundary.A typical network adopts context aggregation modules to extract rich semantic *** also utilizes top-down connection and skips connections for refining boundary *** it still remains disadvantage,an obvious fact is that the problem of false segmentation occurs as the object has very different *** fusion of weak semantic and low-level features leads to context prior *** tackle the issue,we propose a simple yet effective network,which integrates dual context prior and spatial propagation-dubbed *** extends two mainstreams of current segmentation researches:(1)Designing a dual context prior module,which pays attention to context prior again with a shortcut connection.(2)The network can inherently learn semantic aware affinity values for each pixel and refine the *** will present detailed comparisons,which perform on PASCAL VOC 2012 and *** result demonstrates the validation of our approach.

关键词： Deep learning semantic segmentation linear spatial propagation context information

Spatial variability of soil bulk density and its controlling factors in an agricultural intensive area of Chengdu Plain,Southwest China

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Journal of Integrative Agriculture 2019年第2期18卷 290-300页

作者： li Shan li Qi-quan WANG Chang-quan li Bing GAO Xue-song li Yi-ding WU De-yong College of Resources Sichuan Agricultural UniversityChengdu 611130P.R.China

Soil bulk density is a basic but important physic soil property related to soil porosity,soil moisture and hydraulic conductivity,which is crucial to soil quality assessment and land use *** this study,we evaluated the spatial variability of soil bulk density in the 0–20,20–40,40–60 and 60–100 cm layers as well as its affecting factors in Southwest China’s agricultural intensive *** indicated the mean value of surface soil bulk density(0–20 cm)was 1.26 g cm^(–3),significantly lower than that of subsoil(20–100 cm).No statistical difference existed among the subsoil with a mean soil bulk density of 1.54 g cm^(–3).Spatially,soil bulk density played a similar spatial pattern in soil profile,whereas obvious differences were found in *** nugget effects for soil bulk density in the 0–20 and 20–40 cm layers were 27.22 and27.02%while 12.06 and 3.46%in the 40–60 and 60–100 cm layers,respectively,gradually decreasing in the soil profile,indicating that the spatial variability of soil bulk density above 40 cm was affected by structural and random factors while dominated by structural factors under 40 *** organic matter was the controlling factor on the spatial variability of soil bulk density in each *** use and elevation were another two dominated factor controlling the spatial variability of soil bulk density in the 0–20 and 40–60 cm layers,*** genus was one of the dominated factors controlling the spatial variability of soil bulk below 40 cm.

关键词： soil bulk density profile spatial variability controlling factors Chengdu Plain

Sub-channel interference cancellation in SVD-based MIMO system

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The Journal of China Universities of Posts and Telecommunications 2007年第3期14卷 34-37页

作者： WU Ping li li-hua ZHANG Ping Beijing University of Posts and Telecommunications Beijing 100876 China

For singular value decomposition （SVD）-based multiple input multiple output （MIMO） systems, implicit channel state information （CSI） incurs interferences amongst sub-channels if the CSI at the transmitter is not explicit. An improved SVD-based MIMO which can fully cancel the inter sub-channel interferences by reconstructing the transmitter- receiver system matrix on interferences analysis is provided. Simulation results indicate that the proposed algorithm outperforms the traditional SVD-based MIMO in a large degree.

关键词： MIMO systems SVD interference cancellation (IC) CSI feedback

Plasma-etching on monolithic MOFs-based MIM filter boosted chemical sensing

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Nano Research 2024年第4期17卷 2800-2807页

作者： Jianxi liu li Feng Zhihuan li Yang Wu Feng Zhou Yadong Xu Research&Development Institute Northwestern Polytechnical University in ShenzhenShenzhen 518057China State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Yantai Zhongke Research Institute of Advanced Materials and Green Chemical Engineering Shandong Laboratory of Advanced Materials and Green Manufacturing at YantaiYantai 264006China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

Metal-insulator-metal(MIM)cavity as a lithography-free structure to control light transmission and reflection has great potential in the field of optical ***,the dense top metal layer of the MIM prohibits any external medium from entering the dielectric insulation layer,which limits the application of the cavity in the sensing ***,we demonstrate a series of monolithic metal-organic frameworks(MOFs)based MIM cavities,which are treated by plasma etching to provide channels for chemical diffusion and to advance *** modulate the bandwidth of the MIM filters by controlling the MOF thickness as insulator *** plasma-etching is applied to build channels on the top metal layer without altering their saturation and brightness for chemical sensing *** etching time regulates the number and size of channels on the top metal *** behavior is demonstrated on the plasma-etched MOFs-based MIM cavity when external chemicals diffuse in the *** addition,we generate patterned structure of the MOFs-based MIM cavity via plasma-mask method,which can transfer to different substrates and produce a controllable structure color change for chemical *** MIM cavity may promote the advancement and applications of structural color in security imaging,color display,information anticounterfeiting,and color printing.

关键词： metal-organic frameworks(MOFs) spin-coating metal-insulator-metal filter patterns sensing

Study on partial discharge and charge accumulation characteristics of oil‐pressboard insulation under DC superimposed harmonic voltage

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High Voltage 2023年第6期8卷 1215-1224页

作者： Shuqi li Qiang Wang Dongxin He liangkai Wang Qingquan li Wen Si Shandong Provincial Key Laboratory of UHV Transmission Technology and Equipment School of Electrical EngineeringShandong UniversityJinanChina Zibo City Product Quality Inspection Institute ZiboChina School of Information and Electrical Engineering Shandong Jianzhu UniversityJinanChina

The oil‐pressboard insulation on the valve side of the converter transformer withstands pulsating square wave *** voltage contains lots of DC components and high‐order harmonics,which is likely to cause insulation *** partial discharge and space charge experiments of oil‐impregnated pressboard under DC superimposed har-monic voltage are conducted to study the effects of harmonic frequency and DC com-ponents on the discharge and charge accumulation and to explore the correlation mechanism of charge dynamic behaviour and ***,it is found that high‐order harmonic voltage promotes the partial discharge generation,but DC component sup-presses the ***,the charge inside the pressboard is mainly injected in the same polarity and accumulates over *** space charge density near the electrode increases with the increase of harmonic frequency,and the large amount of charge in-jection leads to electric field ***,the electric field direction changes faster,and the frequent charge injection and extraction behaviours make the charge recombination intensify,which promotes the *** the above analysis,the influence law of harmonic voltage on the failure of oil‐pressboard insulation is obtained,providing a theoretical basis for the structural optimisation and condition assessment of the converter transformer insulation.

关键词： harmonic insulation charge

Discrimination Between Broadband Underwater Target Echo and Reverberation Based on Signal Spectral Flatness Feature

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Chinese Journal of Electronics 2019年第3期28卷 542-550页

作者： CHEN Yunfei li Sheng JIA Bing ZHANG Yang WANG Zhenshan li Guijuan School of Naval Architecture Dalian University of Technology Science and Technology on Underwater Test and Control Laboratory

Reverberation is the major interference of active detection, discrimination between target echo and reverberation is difficult when the reverberation is very strong. For the distinguishing of underwater target echo with strong interference, the modulation feature of echo and reverberation spectrum are characterized by signal spectral flatness measure, and the relationship between signal spectral flatness and target physical properties are theoretically formed. A method of discrimination between broadband underwater target echo and reverberation that based on signal spectral flatness characteristics difference is proposed and studied. Sea experiment results of complex underwater target broadband acoustic scattering have shown that signal spectral flatness characteristics of underwater target broadband echo and reverberation have obvious differences. Target echo and reverberation can be well distinguished using the proposed method.

关键词： Echo Reverberation Signal spectral flatness Benchmark

Catalytic fast pyrolysis of walnut shell for alkylphenols production with nitrogen-doped activated carbon catalyst

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Frontiers of Environmental Science & Engineering 2021年第2期15卷 95-105页

作者： Shanwei Ma Hang li Guan Zhang Tahir Iqbal Kai li Qiang Lu State Key Laboratory of Alternate Electric Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Faculty of Agricultural Engineering&Technology PMAS-Arid Agriculture UniversityRawalpindi 46000Pakistan

Alkylphenols are a group of valuable phenolic compounds that can be derived from lignocellulosic *** this study,three activated carbons(ACs)were prepared for catalytic fast pyrolysis(CFP)of walnut shell to produce alkylphenols,including nitrogen-doped walnut shell-derived activated carbon(N/WSAC),nitrogen-doped rice husk-derived activated carbon(N/RHAC)and walnut shell-derived activated carbon(WSAC).Pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS)experiments were carried out to reveal the influences of AC type,pyrolytic temperature,and AC-to-walnut shell(AC-to-WS)ratio on the product *** showed that with nitrogen doping,the N/WSAC possessed stronger capability than WSAC toward the alkylphenols production,and moreover,the N/WSAC also exhibited better effects than N/RHAC to prepare *** the catalysis of N/WSAC,yields of alkylphenols were significantly increased,especially phenol,cresol and *** the increase of pyrolytic temperature,the alkylphenols yield first increased and then decreased,while high selectivity could be obtained at low pyrolytic *** a trend was also observed as the AC-to-WS ratio continuously *** alkylphenols production achieved a maximal yield of 44.19 mg/g with the corresponding selectivity of 34.7%at the pyrolytic temperature of 400℃and AC-to-WS ratio of 3,compared with those of only 4.67 mg/g and 6.1%without *** addition,the possible formation mechanism of alkylphenols was also proposed with the catalysis of N/WSAC.

关键词： Pyrolysis Walnut shell Alkylphenols Nitrogen-doped activated carbon