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Comparing Mn-based oxides filters started by KMnO_(4)versus K_(2)FeO_(4)for ammonium and manganese removal:Formation mechanism of active species

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Journal of Environmental Sciences 2024年第11期145卷 180-192页

作者： Ya Cheng Fengkai shi Tinglin Huang Anqi Miao Gang Wen Chunwei Wang Key Laboratory of Northwest Resource Environment and EcologyMOEXi’an University of Architecture and TechnologyXi’an 710055China Shaanxi Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Collaborative Innovation Center of Water Pollution Control and Water Quality Security Assurance of Shaanxi Province Xi’an University of Architecture and TechnologyXi’an 710055China

A pilot-scale filtration system was adopted to prepare filter media with catalytic activity to remove manganese(Mn^(2+))and ammonium(NH_(4)^(+)-N).Three different combinations of oxidants(KMnO_(4)and K_(2)FeO_(4))and reductants(MnSO_(4)and FeCl_(2))were used during the start-up *** R3 started up by KMnO_(4)and FeCl_(2)(Mn^(7+)→MnO_(x))exhibited excellent catalytic property,and the NH_(4)^(+)-N and Mn^(2+)removal efficiency reached over 80%on the 10th and 35th days,*** R1 started up by K_(2)FeO_(4)and MnSO_(4)(MnO_(x)←Mn^(2+))exhibited the worst catalytic *** R2 started up by KMnO_(4)and MnSO_(4)(Mn^(7+)→MnO_(x)←Mn^(2+))were in *** to Zeta potential results,the Mn-based oxides(MnO_(x))formed by Mn^(7+)→MnO_(x)performed the highest pHIEP and *** higher the pHIEP and pHPZC,the more unfavorable the cation ***,it was inconsistent with its excellent Mn^(2+)and NH_(4)^(+)-N removal abilities,implying that catalytic oxidation played a key *** with XRD and XPS analysis,the results showed that the MnO_(x)produced by the reduction of KMnO_(4)showed early formation of buserite crystals,high degree of amorphous,high content of Mn3+and lattice oxygen with the higher activity to form *** above results showed that MnO_(x)produced by the reduction of KMnO_(4)was more conducive to the formation of active species for catalytic oxidation of NH_(4)^(+)-N and Mn^(2+)*** study provides new insights on the formation mechanisms of the active MnO_(x)that could catalytic oxidation of NH_(4)^(+)-N and Mn^(2+).

关键词： Ammonium Manganese Mn-based oxide Filter Start-up Active species

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Correlations between mineral composition and mechanical properties of granite using digital image processing and discrete element method

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International Journal of Mining Science and Technology 2023年第8期33卷 949-962页

作者： Changdi He Brijes Mishra Qingwen shi Yun Zhao Dajun Lin Xiao Wang Department of Mining Engineering University of UtahSalt Lake City 84112USA College of Mine Safety North China Institute of Science and TechnologyLangfang 065201China Department of Mining Engineering West Virginia UniversityMorgantown 26506USA Department of Electrical and Computer Engineering University of UtahSalt Lake City 84112USA College of Energy and Mining Engineering Shandong University of Science and TechnologyQingdao 266590China

This study investigated the correlations between mechanical properties and mineralogy of granite using the digital image processing(DIP) and discrete element method(DEM). The results showed that the X-ray diffraction(XRD)-based DIP method effectively analyzed the mineral composition contents and spatial distributions of granite. During the particle flow code(PFC2D) model calibration phase, the numerical simulation exhibited that the uniaxial compressive strength(UCS) value, elastic modulus(E), and failure pattern of the granite specimen in the UCS test were comparable to the experiment. By establishing 351 sets of numerical models and exploring the impacts of mineral composition on the mechanical properties of granite, it indicated that there was no negative correlation between quartz and feldspar for UCS, tensile strength(σ_(t)), and E. In contrast, mica had a significant negative correlation for UCS, σ_(t), and E. The presence of quartz increased the brittleness of granite, whereas the presence of mica and feldspar increased its ductility in UCS and direct tensile strength(DTS) tests. Varying contents of major mineral compositions in granite showed minor influence on the number of cracks in both UCS and DTS tests.

关键词： Granite Digital image processing Discrete element method Mineral composition Mechanical properties

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Self-supporting and dual-active 3D Co-S nanosheets constructed by ligand replacement reaction from MOF for rechargeable Al battery

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Journal of Energy Chemistry 2022年第6期31卷 35-43,I0002页

作者： Aijing Lv Songle Lu Mingyong Wang Haotian shi Wenjing Yan Shuqiang Jiao State Key Laboratory of Advanced Metallurgy University of Science and TechnologyBeijingBeijing 100083China Beijing Key Laboratory of Green Recovery and Extraction of Rare and Precious Metals University of Science and TechnologyBeijingBeijing 100083China National Center for Materials Service Safety University of Science and Technology BeijingBeijing 100083China

Metal sulfides with high theoretical capacities are expected as promising cathode materials of Al batteries(AIBs). However, powdery active materials are mainly synthesized and loaded on current collector by insulating binder without capacity. Meanwhile, S as inert element in metal sulfides can not usually provide capacity. So, powdery metal sulfides only exhibit limiting practical capacity and poor cycling stability due to weak conductivity and low mass utilization. Herein, the novel self-supporting and dual-active Co-S nanosheets on carbon cloth (i.e. Co-S/CC) with hierarchically porous structure are constructed as cathode of AIBs. Co-S nanosheets are derived from ZIF-67 nanosheets on CC by a facile ligand replacement reaction. As a result, the binder-free Co-S/CC cathode with good conductivity delivers excellent initial discharge capacity of 383.4 m Ah g^(-1)(0.211 m Ah cm^(-2)) at current density of 200 m A g^(-1)and maintain reversible capacity of 156.9 m Ah g^(-1)(0.086 m Ah cm^(-2)) with Coulombic efficiency of 95.8% after 500 cycles,which are much higher than those of the traditional slurry-coating cathodes. Both Co and S as active elements in Co-S/CC contribute to capacity, which leads to a high mass utilization. This work provides a significant strategy for the construction of self-supporting metallic cathode for advanced high-energy density Al battery.

关键词： Cobalt sulfide Ligand replacement reaction Self-supporting Aluminum battery

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Experimental Study on Thermal Properties and Light-to-Thermal Conversion Performance of Ionic Liquids Based Nanofluids

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Journal of Thermal Science 2023年第6期32卷 1956-1972页

作者： LIU Changhui shi Xiancong GAO Ding CAO Yuqi GU Yanlong RAO Zhonghao School of Low-carbon Energy and Power Engineering China University of Mining and TechnologyXuzhou221116China School of Chemistry and Chemical Engineering Huazhong University of Science and TechnologyWuhan430074China School of Chemistry and Chemical Engineering The Key Laboratory for Green Processing of Chemical Engineering of Xinjiang BingtuanShihezi UniversityShihezi832003China School of Energy and Environmental Engineering Hebei University of TechnologyHebei300130China

As a new type of energy transport medium with high efficiency and high heat transfer performance,nanofluids have shown broad application prospects in the fields of thermodynamics,solar heat collection,microelectronics,thermal energy,and material *** wide liquid range and environmental properties of ionic liquids have drawn ample attention to their application when used as a working fluid,especially as a base solvent of *** ionic liquid-based nanofluids were prepared by a two-step method using 1-ethyl-3-methylimidazole trifluoroacetate ionic liquid as a base solvent and graphene oxide(GO)as a *** properties study reveals that the thermal conductivity could be enhanced by 3.0%with the addition of 0.05 wt%GO,and the viscosity and the specific heat capacity were also subject to study as a function of testing temperature and concentration of ***,the photothermal conversion efficiency of these nanofluids was studied comprehensively under different *** results show that the photothermal conversion efficiency can reach 83%within an irradiation time of 6000 s and the highest temperature of the nanofluids is up to 105.89℃with a maximum photothermal conversion efficiency increase by 29%.

关键词： nanofluids ionic liquid GO photothermal conversion

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Impact of Evaporation Duct on Electromagnetic Wave Propagation During a Typhoon

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Journal of Ocean University of China 2022年第5期21卷 1069-1083页

作者： WANG Shuwen YANG Kunde shi Yang YANG Fan ZHANG Hao School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Ocean Acoustics and Sensing Northwestern Polytechnical UniversityMinistry of Industry and Information TechnologyXi’an 710072China National Key Laboratory of Underwater Information Processing and Control Xi’an 710072China

The evaporation duct,a result of evaporation from the ocean,is a region above the sea surface in which radio waves are refracted *** duct has strong effects on microwave *** cause huge anomalies in marine meteorological parameters that influence the evaporation duct distribution and structure,which in turn affects the propagation of electromagnetic(EM)***,EM wave propagation under the typhoon process has seldom been ***,taking Typhoon Phanfone(201929)as an example,this study uses a dataset from the European Centre for Medium-Range Weather Forecasts,combined with the Naval Atmospheric Vertical Surface Layer Model and the parabolic equation model,to study the evaporation duct’s impact on EM wave propagation during a *** spatial and temporal path loss distributions reveal that large amounts of EM wave energy are emitted from the evaporation duct when the EM wave passes through a typhoon *** average,a typhoon eye causes an approximately 20 dB increase in path loss for EM wave propagation at low antenna ***,the effects of a typhoon eye on EM wave propagation at different signal frequencies and antenna heights are *** results show that a typhoon has a larger impact on EM wave propagation with low signal frequency and high antenna height.

关键词： evaporation duct typhoon ECMWF wave glider electromagnetic wave propagation

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A WiFi Fingerprint Based High-Adaptability Indoor Localization via Machine Learning

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China Communications 2020年第7期17卷 247-259页

作者： Jianzhe Xue Junyu Liu Min Sheng Yan shi Jiandong Li School of Telecommunication Engineering Xidian UniversityXi’an 710071China State Key Laboratory of Integrated Service Networks Xidian UniversityXi’an 710071China

For received signal strength(RSS)fingerprint based indoor localization approaches,the localization accuracy is significantly influenced by the RSS variance,device heterogeneity and environment *** this work,we present a high-adaptability indoor localization(HAIL)approach,which leverages the advantages of both relative RSS values and absolute RSS values to achieve robustness and ***,a backpropagation neural network(BPNN)is devised in HAIL to measure the fingerprints similarities based on absolute RSS *** this aid,the characteristics of the applied area could be specially learned such that HAIL could be adaptive to different *** experiments demonstrate that HAIL achieves high localization accuracy with the average localization error of 0.87 m in the typical ***,HAIL has the minimum amount of large errors and decreases the average localization error by about 30%~50%compared with the existing approaches.

关键词： WiFi absolute error

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Manganese doping to boost the capacitance performance of hierarchical Co_(9)S_(8)@Co(OH)_(2) nanosheet arrays

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Green Energy & Environment 2022年第6期7卷 1289-1297页

作者： Lingxia Zheng Weiqing Ye Pengju Yang Jianlan Song Xiaowei shi Huajun Zheng State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology Zhejiang University of TechnologyHangzhou310014China Department of Applied Chemistry Zhejiang University of TechnologyHangzhou310014China

Transition metal sulfides(TMSs)have been regarded as greatly promising electrode materials for supercapacitors because of abundant redox electroactive sites and outstanding ***,we report a self-supported hierarchical Mn doped Co_(9)S_(8)@Co(OH)_(2) nanosheet arrays on nickel foam(NF)substrate by a one-step metal–organic-framework(MOF)engaged approach and a subsequent sulfurization *** results reveal that the introduction of manganese endows improved electric conductivity,enlarged electrochemical specific surface area,adjusted electronic structure of Co_(9)S_(8)@Co(OH)_(2) and enhanced interfacial activities as well as facilitated reaction kinetics of *** optimal Mn doped Co_(9)S_(8)@Co(OH)_(2) electrode exhibits an ultrahigh specific capacitance of 3745 F g^(-1) at 1 A g^(-1)(5.618 F cm^(-2) at 1.5 mA cm^(-2))and sustains 1710 F g^(-1) at 30 A g^(-1)(2.565 F cm^(-2) at 45 mA cm^(-2)),surpassing most reported values on ***,a battery-type asymmetric supercapacitor(ASC)device is constructed,which delivers high energy density of 50.2 Wh kg^(-1) at power density of 800 W kg^(-1),and outstanding long-term cycling stability(94%capacitance retention after 8000 cycles).The encouraging results might offer an effective strategy to optimize the TMSs for energy-storage devices.

关键词： Mn doped Co_(9)S_(8)@Co(OH)_(2) MOF High capacitance Asymmetric supercapacitor

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Adjoint-based robust optimization design of laminar flow wing under flight condition uncertainties

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Chinese Journal of Aeronautics 2023年第6期36卷 19-34页

作者： Yifu CHEN Hanyue RAO Yiju DENG Tihao YANG Yayun shi Junqiang BAI School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China The First Aircraft Design and Research Institute Xi’an 710089China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China

It is an inherent uncertainty problem that the application of laminar flow technology to the wing of large passenger aircraft is affected by flight *** order to seek a more robust natural laminar flow control effect,it is necessary to develop an effective optimization design ***,attention must be given to the impact of crossflow(CF)instability brought on by the sweep *** paper constructs a robust optimization design framework based on discrete adjoint methods and non-intrusive polynomial *** prediction is implemented by coupled Reynolds-Averaged Navier-Stokes(RANS)and simplified e^(N)method,which can consider both Tollmien-Schlichting(TS)wave and crossflow vortex *** have performed gradient enhancement processing on the general Polynomial Chaos Expansion(PCE),which is advantageous to reduce the computational cost of single uncertainty *** processing takes advantage of the gradient information obtained by solving the coupled adjoint equations considering *** statistical moment gradient solution used for the robust optimization design also uses the derivatives of coupled adjoint *** framework is applied to the robust design of a 25°swept wing with infinite span in transonic *** uncertainty quantification and sensitivity analysis on the baseline wing shows that the uncertainty quantification method in this paper has high accuracy,and qualitatively reveals the factors that dominate in different flow field *** the robust optimization design,the mean and standard deviation of the drag coefficient can be reduced by 29%and 45%,respectively,and compared with the deterministic optimization design results,there is less possibility of forming shock waves under flight condition *** optimization results illustrate the trade-off between the transition delay and the wave drag reduction.

关键词： Adjoint method Gradient-based optimization Laminar-turbulent transition Robust design Uncertainty propagation

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Dynamic Write-Voltage Design and Read-Voltage Optimization for MLC NAND Flash Memory

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China Communications 2024年第12期21卷 297-308页

作者： Cai Runbin Fang Yi shi Zhifang Dai Lin Han Guojun School of Information Engineering Guangdong University of TechnologyGuangdong 510006China

To mitigate the impact of noise and inter-ference on multi-level-cell(MLC)flash memory with the use of low-density parity-check(LDPC)codes,we propose a dynamic write-voltage design scheme con-sidering the asymmetric property of raw bit error rate(RBER),which can obtain the optimal write voltage by minimizing a cost *** order to further improve the decoding performance of flash memory,we put forward a low-complexity entropy-based read-voltage optimization scheme,which derives the read voltages by searching for the optimal entropy value via a log-likelihood ratio(LLR)-aware cost *** results demonstrate the superiority of our proposed dynamic write-voltage design scheme and read-voltage optimization scheme with respect to the existing counterparts.

关键词： error correction coding multi-level-cell(MLC) NAND flash memory read voltage write voltage

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Divergence-degenerate spatial multiplexing towards future ultrahigh capacity,low error-rate optical communications

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Light(Science & Applications) 2022年第6期11卷 1253-1263页

作者： Zhensong Wan Yijie Shen Zhaoyang Wang Zijian shi Qiang Liu Xing Fu Key Laboratory of Photonic Control Technology(Tsinghua University) Ministry of Education100084 BeijingChina State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua University100084 BeijingChina Optoelectronics Research center University of SouthamptonSouthampton SO171BJUK

Spatial mode(de)multiplexiing of orbital angular momentum(OAM)beams is a promising solution to address future bandwidth issues,but the rapidly increasing divergence with the mode order severely limits the practically addressable number of OAM *** we present a set of multi-vortex geometric beams(MVGBs)as high-dimensional information carriers for free-space optical communication,by virtue of three independent degrees of freedom(DoFs)including central OAM,sub-beam OAM,and coherent-state *** novel modal basis set has high divergence degeneracy,and highly consistent propagation behaviors among all spatial modes,capable of increasing the addressable spatial channels by two orders of magnitude than OAM basis as *** experimentally realize the tri-DoF MVGB mode(de)multiplexing and data transmission by the conjugated modulation method,demonstrating lower error rates caused by center offset and coherent background noise,compared with OAM *** work provides a potentially useful basis for the next generation of large-scale dense data communication.

关键词： optical error coherent

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