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Achieving robust nitritation in a modified continuous-flow reactor: From micro-granule cultivation to nitrite-oxidizing bacteria elimination

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Journal of Environmental Sciences 2023年第2期124卷 117-129页

作者： Wenru Liu Jiajun Song Jianfang Wang Xiaoming Ji Yaoliang Shen Dianhai Yang National&Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology Suzhou University of Science and TechnologySuzhou 215009China School of Environmental Science and Engineering Suzhou University of Science and TechnologySuzhou 215009China College of Resources and Environmental Sciences Nanjing Agricultural UniversityNanjing 210095China State Key Laboratory of Pollution Control and Resources Reuse Tongji UniversityShanghai 200092China

In this study,a modified continuous-flow nitrifying reactor was successfully operated for rapid cultivation of micro-granules and achieving robust nitritation.Results showed that sludge granulation with mean size of ca.100μm was achieved within three weeks by gradually increasing settling velocity-based selection pressure from 0.48 to 0.9 m/hr.Though Nitrospira like nitrite-oxidizing bacteria(NOB)were enriched in the micro-granules with a ratio between ammonia-oxidizing bacteria(AOB)and NOB of 5.7%/6.5% on day 21,fast nitritation was achieved within one-week by gradually increasing of influent ammonium concentration(from 50 to 200 mg/L).Maintaining ammonium in-excess was the key for repressing NOB in the micro-granules.Interestingly,when the influent ammonium concentration switched back to 50 mg/L still with the residual ammonium of 15–25 mg/L,the nitrite accumulation efficiency increased from 90%to 98%.Experimental results suggested that the NOB repression was intensified by both oxygen and nitrite unavailability in the inner layers of micro-granules.Unexpectedly,continuous operation with ammonium in excess resulted in overproduction of extracellular polysaccharides and overgrowth of some bacteria(e.g.,Nitrosomonas,Arenimonas,and Flavobacterium),which deteriorated the micro-granule stability and drove the micro-granules aggregation into larger ones with irregular morphology.However,efficient nitritation was stably maintained with extremely high ammonium oxidation potential(>50 mg/g VSS/hr)and nearly complete washout of NOB was obtained.This suggested that smooth and spherical granule was not a prerequisite for achieving NOB wash-out and maintaining effective nitritation in the granular reactor.Overall,the microgranules exhibited a great practical potential for high-rate nitritation.

关键词： Continuous flow Granulation Nitritation Nitrate-oxidizing bacteria repression

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Stability Analysis of Inverse Lax-Wendroff Procedure for a High order Compact Finite Difference Schemes

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Communications on Applied Mathematics and Computation 2024年第1期6卷 142-189页

作者： Tingting Li jianfang Lu Pengde wang School of Mathematics and Statistics Henan UniversityKaifeng475004HenanChina School of Mathematics South China University of TechnologyGuangzhou510641GuangdongChina College of Mathematics and Information Science Henan University of Economics and LawZhengzhou450046HenanChina

This paper considers the finite difference(FD)approximations of diffusion operators and the boundary treatments for different boundary conditions.The proposed schemes have the compact form and could achieve arbitrary even order of accuracy.The main idea is to make use of the lower order compact schemes recursively,so as to obtain the high order compact schemes formally.Moreover,the schemes can be implemented efficiently by solving a series of tridiagonal systems recursively or the fast Fourier transform(FFT).With mathematical induction,the eigenvalues of the proposed differencing operators are shown to be bounded away from zero,which indicates the positive definiteness of the operators.To obtain numerical boundary conditions for the high order schemes,the simplified inverse Lax-Wendroff(SILW)procedure is adopted and the stability analysis is performed by the Godunov-Ryabenkii method and the eigenvalue spectrum visualization method.Various numerical experiments are provided to demonstrate the effectiveness and robustness of our algorithms.

关键词： Compact scheme Diffusion operators Inverse Lax-Wendroff(ILW) Fourier analysis Eigenvalue analysis

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A Large-Scale Group Decision Making Model Based on Trust Relationship and Social Network Updating

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工程与科学中的计算机建模(英文) 2024年第1期138卷 429-458页

作者： Rongrong Ren Luyang Su Xinyu Meng Jianfang Wang Meng Zhao School of Business Administration Northeastern UniversityShenyang110819China School of Management Northeastern University at QinhuangdaoQinhuangdao066004China School of Modern Logistics Shanxi Vocational University of Engineering Science and TechnologyTaiyuan030031China Business School Sichuan UniversityChengdu610064China

With the development of big data and social computing,large-scale group decisionmaking(LGDM)is nowmerging with social networks.Using social network analysis(SNA),this study proposes an LGDM consensus model that considers the trust relationship among decisionmakers(DMs).In the process of consensusmeasurement:the social network is constructed according to the social relationship among DMs,and the Louvain method is introduced to classify social networks to form subgroups.In this study,the weights of each decision maker and each subgroup are computed by comprehensive network weights and trust weights.In the process of consensus improvement:A feedback mechanism with four identification and two direction rules is designed to guide the consensus of the improvement process.Based on the trust relationship among DMs,the preferences are modified,and the corresponding social network is updated to accelerate the consensus.Compared with the previous research,the proposedmodel not only allows the subgroups to be reconstructed and updated during the adjustment process,but also improves the accuracy of the adjustment by the feedbackmechanism.Finally,an example analysis is conducted to verify the effectiveness and flexibility of the proposed method.Moreover,compared with previous studies,the superiority of the proposed method in solving the LGDM problem is highlighted.

关键词： Large-scale group decision making social network updating trust relationship group consensus feedback mechanism

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Analysis of Pressure Forcings for the Vertical Turbulent Fluxes in the Convective Boundary Layer at Gray Zone Resolutions

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Journal of Meteorological Research 2023年第6期37卷 841-854页

作者： Yahua wang Xiaoping CHENG jianfang FEI Bowen ZHOU College of Meteorology and Oceanography National University of Defense TechnologyChangsha410005China Key Laboratory of Electro-Optical Countermeasures Test and Evaluation Technology Luoyang471000China Key Laboratory for Mesoscale Severe Weather Ministry of EducationSchool of Atmospheric SciencesNanjing UniversityNanjing210000China

At kilometer and sub-kilometer resolutions,known as the numerical gray zone for boundary layer turbulence,the atmospheric boundary layer turbulence becomes partially resolved and partially subgrid-scale(SGS) in a numerical model,thus requiring scale-adaptive turbulence schemes.Such schemes are often built by modifying the existing parameterizations,either the planetary boundary layer(PBL) schemes or the large-eddy simulation(LES) closures,to produce the right SGS turbulent fluxes at gray zone resolutions.However,the underlying forcings responsible for the changes in the vertical turbulent fluxes are largely ignored in these approaches.This study follows the original approach of Wyngaard(2004) and analyzes the turbulent buoyancy and momentum flux budgets,to gain a better understanding of the variations of flux forcings at gray zone resolutions.The investigation focuses on the pressure covariance term,which is one of the most dominant terms in the budget equations.By using the coarse-grained LES of a dry convective boundary layer(CBL) case as reference,two widely-used pressure covariance models are evaluated and optimized across the gray zone resolution range.The optimized linear model is further evaluated a priori against another dry CBL case with a different bulk stability,and a shallow-cumulus-topped boundary layer case.The model applies well to both cases,and notably shows good performance for the cloud layer.Based on the analysis of the flux forcings and the optimized pressure model,a scale-adaptive turbulence model for the gray zone is derived from the steady-state flux budgets.

关键词： convective boundary layer gray zone flux budget pressure covariance turbulence parameterization

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Highly efficient electrocatalytic nitrogen fixation enabled by the bridging effect of Ru in plasmonic nanoparticles

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Nano Research 2023年第1期16卷 360-370页

作者： Hang Yin Jinwu Hu Caihong Fang Yuyang wang Lixia Ma Nan Zhang Shouren Zhang Ruibin Jiang Jianfang Wang Shaanxi Key Laboratory for Advanced Energy Devices Shaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science and EngineeringShaanxi Normal UniversityXi’an 710119China College of Chemistry and Materials Science The Key Laboratory of Functional Molecular SolidsMinistry of EducationAnhui Laboratory of Molecular-Based MaterialsCenter for Nano Science and TechnologyKey Laboratory of Electrochemical Clean Energy of Anhui Higher Education InstitutesAnhui Normal UniversityWuhu 241000China Henan Provincial Key Laboratory of Nanocomposites and Applications Institute of Nanostructured Functional MaterialsHuanghe Science and Technology CollegeZhengzhou 450006China Department of Physics The Chinese University of Hong KongHong Kong 999077China

Plasmon-generated hot electrons show great potential for driving chemical reactions.The utilization efficiency of hot electrons is highly dependent on the interaction of the electronic states at the interfaces between plasmonic nanoparticles and other materials/molecules.Strong interaction can produce new hybridized electron states,which permit direct hot-electron transfer,a more efficient transfer mechanism.However,Au usually has very weak interaction with most molecules because of its inertness,which makes direct hot-electron transfer impossible.Herein,the improvement of the hot-electron transfer efficiency from Au to N_(2)is demonstrated by introducing a Ru bridging layer.Both the N_(2)fixation rate and Faradic efficiency(FE)are enhanced by the excitation of plasmons.The enhancement of the N_(2)fixation rate is found to arise from plasmon-generated hot electrons.Theoretical calculations show that the strong interaction of the Ru electronic states with the N_(2)molecular orbitals produces new hybridized electronic states,and the Ru d electrons also strongly couple with the Au sp electrons.Such a bridging role of Ru makes direct hot-electron transfer from Au to N_(2)possible,improving the FE of nitrogen fixation.Our findings demonstrate a new approach to increasing the utilization efficiency of plasmonic hot electrons for chemical reactions and will be helpful to the design of plasmonic catalysts in the future.

关键词： electrocatalytic nitrogen fixation Au/Ru electrocatalysts localized surface plasmon resonance electronic state hybridization hot electron

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Spatiotemporal evolution of C3/C4 vegetation and its controlling factors in southern China since the last glacial maximum

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Science China Earth Sciences 2019年第8期62卷 1256-1268页

作者： Linlin CUI jianfang HU Xu wang Institute of Geology and Geophysics Chinese Academy of SciencesBeijing100029China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China Guanzhou Institute of Geochemistry Chinese Academy of SciencesBeijing510640China

To date, few research have been reported on the evolution of C3/C4 vegetation in southern China, and the main mechanism influencing the evolution of C3/C4 vegetation is unclear. That makes it difficult for researchers to understand the competition mechanism of C3 and C4 plants under different climate environments and its relationship with the climate factors. It is also not conducive for researchers to assess the influence of future climate change on regional C3/C4 vegetation. Exactly, C3/C4 vegetation change in the regional-scale will have a significant impact on the global carbon cycle and agricultural production.Therefore, it is especially important to reconstruct the evolutionary history of C3/C4 vegetation in southern China and clarify the influencing mechanism of climate change. In this study, we systematically analyzed stable carbon isotope(δ13 C) of the longchain n-alkanes in sediment samples from eight lakes and four peat profiles in southern China, to reconstruct the spatiotemporal evolution of C3/C4 vegetation in these regions since the Last Glacial Maximum(LGM) and to investigate the climate factors that affect the C4 plant abundance change in the research area. The integrated long-chain n-alkane(C27–C33) stable carbon isotope results of samples from Zhanjiang Huguangyan Maar Lake, Xingyun Lake, Lugu Lake and Dingnan peat showed that, from the LGM to the Early Holocene, C4 plant relative abundance exhibited a gradually increasing trend from 21% to 34%. In the Middle Holocene, the C4 plant abundance significantly declined and reached a lowest value of 10%. In space, the C4 plant abundance generally exhibited a gradually declining trend from south to north in the LGM and the Early Holocene, while it showed an opposite trend in the Holocene Climate Optimum(6.0 cal ka BP). It reflected that the main influencing factor on C4 plants spatial distribution was changing from temperature to precipitation. This study indicated that temperature was the dominant factor affecting C4 plant distribution in southern Ch

关键词： Stable carbon isotope Long-chain n-alkanes C3/C4vegetation Last Glacial Maximum Holocene Climate Optimum period

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Development and optimized pairing of mouse monoclonal antibodies for detecting hemagglutinin in novel H7 subtype influenza viruses

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Science China(Life Sciences) 2020年第2期63卷 279-289页

作者： Huijuan wang jianfang Zhou Dayan wang Baoying Huang Wenjie Tan NHC Key Laboratory of Biosafety National Institute for Viral Disease Control&PreventionChinese Center for Disease Control and PreventionChina CDCBeijing 102206China

The H7 subtype avian influenza threatens public health with respect to poultry and humans.Thus,a specific and sensitive diagnostic test is essential for the management of H7 subtype influenza infections.In this study,five mouse monoclonal antibodies(mAbs)against hemagglutinin(HA)of influenza A/Anhui/1/2013(H7N9)were produced and characterized by the Western blot,immunofluorescence,and hemagglutination inhibition assays.All five specific mAbs reacted with the HA protein of H7N9 but not with that of H1 N1,H3 N2,or H5 N1.With the combination arrays of capture and detection antibodies,the matched pair m Abs(1 C4-coated and 2 D7-labeled)were selected and employed in a double-antibody sandwich ELISA(DASELISA).Detection limits of the sandwich ELISA were 0.45 ng mL^–1 for the HA protein derived from A/Anhui/1/2013(H7N9);or 1 and 2 HA units/50μL for A/Anhui/1/2013(H7N9)and A/GD/17 SF003/2016(H7N9),respectively.These anti-HA mAbs against subtype H7 and the novel DAS-ELISA provide a valuable approach for specific detection of the H7 subtype influenza virus and quantification of its HA protein,especially for the novel epidemic H7N9.

关键词： influenza A H7 subtype hemagglutinin monoclonal antibodies sandwich ELISA

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(Metal yolk)/(porous ceria shell)nanostructures for high-performance plasmonic photocatalysis under visible light

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Nano Research 2020年第5期13卷 1354-1362页

作者： Nina Jiang Danyang Li Lili Liang Qing Xu Lei Shao Shi-Bin wang Aizheng Chen Jianfang Wang College of Chemical Engineering Huaqiao UniversityXiamen 361021China Department of Physics The Chinese University of Hong KongShatinHong Kong SARChina Country Fujian Provincial Key Laboratory of Biochemical Technology(Huaqiao University) Xiamen 361021China

We describe a route to the preparation of(metal yolk)/(porous ceria shell)nanostructures through the heterogeneous growth of ceria on porous metal nanoparticles followed by the calcination-induced shrinkage of the nanoparticles.The approach allows for the control of the ceria shell thickness,the metal yolk composition and size,which is difficult to realize through common templating approaches.The yolk/shell nanostructures with monometallic Pt and bimetallic PtAg yolks featuring plasmon-induced broadband light absorption in the visible region are rationally designed and constructed.The superior photocatalytic activities of the obtained nanostructures are demonstrated by the selective oxidation of benzyl alcohol under visible light.The excellent activities are ascribed to the synergistic effects of the metal yolk and the ceria shell on the light absorption,electron-hole separation and efficient mass transfer.Our synthesis of the(metal yolk)/(porous ceria shell)nanostructures points out a way to the creation of sophisticated heteronanostructures for high-performance photocatalysis.

关键词： yolk-shell nanostructures ceria metal nanoparticles plasmon resonance photocatalysis

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FusionNN:A Semantic Feature Fusion Model Based on Multimodal for Web Anomaly Detection

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Computers, Materials & Continua 2024年第5期79卷 2991-3006页

作者： Li wang Mingshan Xia Hao Hu jianfang Li Fengyao Hou Gang Chen Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China Spallation Neutron Source Science Center(SNSSC) Dongguan523803China School of Nuclear Technology University of Chinese Academy of SciencesBeijing100049Chin

With the rapid development of the mobile communication and the Internet,the previous web anomaly detectionand identificationmodels were built relying on security experts’empirical knowledge and attack features.Althoughthis approach can achieve higher detection performance,it requires huge human labor and resources to maintainthe feature library.In contrast,semantic feature engineering can dynamically discover new semantic featuresand optimize feature selection by automatically analyzing the semantic information contained in the data itself,thus reducing dependence on prior knowledge.However,current semantic features still have the problem ofsemantic expression singularity,as they are extracted from a single semantic mode such as word segmentation,character segmentation,or arbitrary semantic feature extraction.This paper extracts features of web requestsfrom dual semantic granularity,and proposes a semantic feature fusion method to solve the above problems.Themethod first preprocesses web requests,and extracts word-level and character-level semantic features of URLs viaconvolutional neural network(CNN),respectively.By constructing three loss functions to reduce losses betweenfeatures,labels and categories.Experiments on the HTTP CSIC 2010,Malicious URLs and HttpParams datasetsverify the proposedmethod.Results show that compared withmachine learning,deep learningmethods and BERTmodel,the proposed method has better detection performance.And it achieved the best detection rate of 99.16%in the dataset HttpParams.

关键词： Feature fusion web anomaly detection multimodal convolutional neural network(CNN) semantic feature extraction

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Giant two-photon absorption of anatase TiO_(2) in Au/TiO_(2) core-shell nanoparticles

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光子学研究:英文版 2023年第7期11卷 1303-1313页

作者： LIJIE wang TSZ HIM CHOW MALTE OPPERMANN Jianfang Wang MAJED CHERGUI Laboratory of Ultrafast Spectroscopy ISIC and Lausanne Centre for Ultrafast Science(LACUS)École Polytechnique Fédérale de Lausanne(EPFL)CH-1015 LausanneSwitzerland Department of Physics The Chinese University of Hong KongShatinHong Kong SARChina Division of Physical Science and Engineering King Abdullah University of Science and Technology(KAUST)ThuwalKingdom of Saudi Arabia Chemistry Department University of Basel4001 BaselSwitzerland

We report on deep-to-near-UV transient absorption spectra of core-shell Au∕SiO_(2) and Au∕TiO_(2) nanoparticles(NPs) excited at the surface plasmon resonance of the Au core, and of UV-excited bare anatase TiO_(2) NPs. The bleaching of the first excitonic transition of anatase TiO_(2) at ~3.8 e V is a signature of the presence of electrons/holes in the conduction band(CB)/valence band(VB) of the material. We find that while in bare anatase TiO_(2) NPs, two-photon excitation does not occur up to the highest used fluences(1.34 mJ∕cm^(2)), it takes place in the TiO_(2) shell at moderate fluences(0.18 mJ∕cm^(2)) in Au∕TiO_(2) core-shell NPs, as a result of an enhancement due to the plasmon resonance. We estimate the enhancement factor to be of the order of ~10~8–10~9. Remarkably, we observe that the bleach of the 3.8 eV band of TiO_(2) lives significantly longer than in bare TiO_(2), suggesting that the excess electrons/holes in the conduction/valence band are stored longer in this material.

关键词： material absorption excited

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