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Synthesis of chitosan-based grafting magnetic flocculants for flocculation of kaolin suspensions

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Journal of Environmental sciences 2024年第5期139卷 193-205页

作者： Chuang Liu Xiaoyu Wang Sicong Du Wenyan Liang Beijing Key Lab for Source control Technology of Water Pollution/engineering Research Center for Water Pollution Source control&Eco-remediation/college of Environmental science and engineering Beijing Forestry UniversityBeijing 100083China

A series of novel chitosan-based magnetic flocculants FS@CTS-P(AM-DMC)was prepared by molecular structure control.The characterization results showed that FS@CTS-P(AM-DMC)had a uniform size of about 21.46 nm,featuring a typical core-shell structure,and the average coating layer thickness of CTS-P(AM-DMC)was about 5.03 nm.FS@CTS-P(AM-DMC)exhibited excellent flocculation performance for kaolin suspension,achieved 92.54% turbidity removal efficiency under dosage of 150 mg/L,pH 7.0,even at high turbidity(2000 NTU)with a removal efficiency of 96.96%.The flocculation mechanism was revealed to be dominated by charge neutralization under acidic and neutral conditions,while adsorption and bridging effects play an important role in alkaline environments.The properties of magnetic aggregates during flocculation,breakage,and regeneration were studied at different pH levels and dosages.In the process of magnetophoretic,magnetic particles collide and adsorb with kaolin particles continuously due to magnetic and electrostatic attraction,transform into magnetic chain clusters,and then further form three-dimensional network magnetic aggregates that can capture free kaolin particles and other chain clusters.Particle image velocimetry confirmed the formation of eddy current of magnetic flocs and experienced three stages:acceleration,stabilization,and deceleration.

关键词： Magnetic flocculation Chitosan Fe_(3)O_(4) Graft copolymerization PIV

Linear Quadratic Optimal control for Systems Governed by First-Order Hyperbolic Partial Differential Equations

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Journal of Systems science & Complexity 2024年第1期37卷 230-252页

作者： XUE Xiaomin XU Juanjuan ZHANG Huanshui School of control science and engineering Shandong UniversityJinan 250061China college of Electrical engineering and Automation Shandong University of Science and TechnologyQingdao 266000China

This paper focuses on linear-quadratic(LQ)optimal control for a class of systems governed by first-order hyperbolic partial differential equations(PDEs).Different from most of the previous works,an approach of discretization-then-continuousization is proposed in this paper to cope with the infinite-dimensional nature of PDE systems.The contributions of this paper consist of the following aspects:(1)The differential Riccati equations and the solvability condition of the LQ optimal control problems are obtained via the discretization-then-continuousization method.(2)A numerical calculation way of the differential Riccati equations and a practical design way of the optimal controller are proposed.Meanwhile,the relationship between the optimal costate and the optimal state is established by solving a set of forward and backward partial difference equations(FBPDEs).(3)The correctness of the method used in this paper is verified by a complementary continuous method and the comparative analysis with the existing operator results is presented.It is shown that the proposed results not only contain the classic results of the standard LQ control problem of systems governed by ordinary differential equations as a special case,but also support the existing operator results and give a more convenient form of computation.

关键词： Discretization-then-continuousization method first-order hyperbolic partial differential equations forward and backward partial difference equations linear quadratic optimal control.

Regulation of rhizosphere microenvironment by rice husk ash for reducing the accumulation of cadmium and arsenic in rice

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Journal of Environmental sciences 2024年第2期136卷 1-10页

作者： Yi Jiang Ya Liu Xuantao Yi Peng Zeng Bohan Liao Hang Zhou Jiaofeng Gu college of Environmental science and engineering Central South University of Forestry and TechnologyChangsha 410004China Hunan engineering Laboratory for control of Rice Quality and Safety Changsha 410004China

It is important to reduce Cd and As content in brown rice in contaminated paddy soils.We conducted research on the effects of rice husk ash (RHA) on the Cd and As in the rhizosphere microenvironment (soil,porewater,and iron plaque) and measured the Cd,As,and Si content in rice plants.The main elements in RHA were Si (29.64%) and O (69.17%),which had the maximum adsorption capacity for Cd was 42.49 mg/kg and for As was 18.62 mg/kg.Soil pH and available Si content increased,while soil available Cd and As decreased following application of 0.5%–2%RHA.RHA promote the transformation of Cd to insoluble fraction,while As was transformed from a poorly soluble form to a more active one.RHA reduced Cd content and increased Si content in porewater,and reduced As only at the later rice growth stages.RHA increased the amount of iron plaque,thereby decreasing the Cd content in iron plaque,while increased the As content in it.Cd and inorganic As content in brown rice were decreased,to 0.31 mg/kg and 0.18 mg/kg,respectively.The decrease of Cd in brown rice was due to the decrease of Cd mobility in soil,thereby reducing root accumulation,while the decrease of As in brown rice was affected by the transport from roots to stems.Therefore,RHA can be considered as a safe and efficient in-situ remediation amendment for Cd and As co-contaminated paddy soil.

关键词： Rice husk ash(rha) Cadmium Arsenic Silicon Rice Soil

Insect-specific RNA virus affects the stylet penetration activity of brown citrus aphid(Aphis citricidus)to facilitate its transmission

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Insect science 2024年第1期31卷 255-270页

作者： Xin An Qiaoying Gu Jing Wang Tengyu Chang Wei Zhang Jin-Jun Wang Jinzhi Niu Key Laboratory of Entomology and Pest control engineering College of Plant ProtectionAcademy of Agricultural ScienceSouthwest UniversityChongqingChina

Sap-sucking insects often transmit plant viruses but also carry insect viruses,which infect insects but not plants.The impact of such insect viruses on insect host biology and ecology is largely unknown.Here,we identified a novel insect-specific virus carried by brown citrus aphid(Aphis citricidus),which we tentatively named Aphis citricidus picornavirus(AcPV).Phylogenetic analysis discovered a monophyletic cluster with AcPV and other unassigned viruses,suggesting that these viruses represent a new family in order Picornavirales.Systemic infection with AcPV triggered aphid antiviral immunity mediated by RNA interference,resulting in asymptomatic tolerance.Importantly,we found that AcPV was transmitted horizontally by secretion of the salivary gland into the feeding sites of plants.AcPV influenced aphid stylet behavior during feeding and increased the time required for intercellular penetration,thus promoting its transmission among aphids with plants as an intermediate site.The gene expression results suggested that this mechanism was linked with transcription of salivary protein genes and plant defense hormone signaling.Together,our results show that the horizontal transmission of AcPV in brown citrus aphids evolved in a manner similar to that of the circulative transmission of plant viruses by insect vectors,thus providing a new ecological perspective on the activity of insect-specific viruses found in aphids and improving the understanding of insect virus ecology.

关键词： electrical penetration graph feeding behavior insect virus transmission Picornavirales salivary protein

Global adaptive output-feedback tracking with prescribed performance for uncertain nonlinear systems

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science China(Information sciences) 2024年第5期67卷 150-164页

作者： Yuan WANG Yungang LIU School of control science and engineering Shandong University

At present, one typical control strategy for guaranteeing transient and steady-state performance is funnel control and prescribed performance control. The strategy features completely discarding the system nonlinearities, even if they are completely known and available. Such an intrinsic feature requires the controller to produce a larger control effect to eliminate the negative impact caused by the high nonlinearities, leading to a conservative controller. In this paper, we fully take advantage of known information on nonlinearities in control design, instead of completely discarding it as done in funnel control. Particularly, we leverage adaptive techniques(i.e., high-gain dynamic compensation) to deal with unknown system nonlinearities. Meanwhile, we integrate the tools of output feedback, tracking control, and the performance guarantee.As such, an adaptive output-feedback scheme is developed for global tracking with spatiotemporal performance specifications: arbitrarily given tracking accuracy and accuracy-ensured time. A simulation example supports the developed approach.

关键词： uncertain nonlinear systems output feedback prescribed performance unknown control direction dynamic high gain global tracking

Exact Box-Constrained Economic Operating Region for Power Grids Considering Renewable Energy Sources

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 514-523页

作者： Huating Xu Bin Feng Chutong Wang Chuangxin Guo Jian Qiu Mingyang Sun college of Electrical engineering Zhejiang UniversityHangzhou 310027China Department of control science and engineering Zhejiang UniversityHangzhou 310027China

The growing integration of renewable energy sources manifests as an effective strategy for reducing carbon emissions. This paper strives to efficiently approximate the set of optimal scheduling plans(OSPs) to enhance the performance of the steady-state adaptive cruise method(SACM) of power grid, improving the ability of dealing with operational uncertainties. Initially, we provide a mathematical definition of the exact boxconstrained economic operating region(EBC-EOR) for the power grid and its dispatchable components. Following this, we introduce an EBC-EOR formulation algorithm and the corresponding bi-level optimization models designed to explore the economic operating boundaries. In addition, we propose an enhanced big-M method to expedite the computation of the EBCEOR. Finally, the effectiveness of the EBC-EOR formulation, its economic attributes, correlation with the scheduling plan underpinned by model predictive control, and the significant improvement in computational efficiency(over twelvefold) are verified through case studies conducted on two test systems..

关键词： Exact box-constrained economic operating region(EBC-EOR) big-M method intelligent scheduling steady-state adaptive cruise uncertainty renewable energy source

Fast-response,high-sensitivity multi-modal tactile sensors based on PPy/Ti_(3)C_(2)T_(x) films for multifunctional applications

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Nano Research 2024年第5期17卷 4410-4419页

作者： Guangshuai Xi Dongzhi Zhang Mingcong Tang Hao Zhang Yuehang Sun Yubiao Zhang Haolin Cai Hui Xia Dandi Zhou college of control science and engineering China University of Petroleum(East China)Qingdao 266580China

In recent years,multi-modal flexible tactile sensors have become an important direction in the development of electronic skin because of their excellent sensitivity,flexibility and wearable properties.In this work,a humidity-pressure multi-modal flexible sensor based on polypyrrole(PPy)/Ti_(3)C_(2)T_(x) sensitive film packaged with porous polydimethylsiloxane(PDMS)is investigated by combining the sensitive structure generation mechanism of in situ polymerization to achieve the simultaneous detection of humidity and pressure,which has a sensitivity of 89,113.4Ω/%RH in a large humidity range of 0%-97%RH,and response/recovery time of 2.5/1.9 s.The tactile pressure sensing has a high sensitivity,a fast response of 67/52 ms,and a wide detection limit.The device also has excellent performance in terms of stability and repeatability,making it promising for respiratory pattern and motion detection.This work provides a new solution to address the construction of multi-modal tactile sensors with potential applications in the fields of medical health,epidemic prevention.

关键词： multi-modal sensors humidity-pressure tactile sensors resistive sensors Ti3C2Tx human respiratory and motion detection

Boosting oxygen vacancies by modulating the morphology of Au decorated In_(2)O_(3)with enhanced CO_(2)hydrogenation activity to CH_(3)OH

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Journal of Environmental sciences 2024年第6期140卷 91-102页

作者： Ruxian Hou Jiewen Xiao Qian Wu Tianyu Zhang Qiang Wang Beijing Key Lab for Source control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China engineering Research Center for Water Pollution Source control&Eco-remediation College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China

CO_(2)hydrogenation to methanol has become one of the most promising ways for CO_(2)utilization,however,the CO_(2)conversion rate and methanol selectivity of this reaction still need to be improved for industrial application.Here we investigated the structure-activity relationship for CO_(2)conversion to methanol of In_(2)O_(3)-based catalysts by modulating morphology and decorating Au.Three different Au/In_(2)O_(3)catalysts were prepared,their activity follow the sequence of Au/In_(2)O_(3)-nanosphere(Au/In_(2)O_(3)-NS)>Au/In_(2)O_(3)-nanoplate(Au/In_(2)O_(3)-NP)>Au/In_(2)O_(3)-hollow microsphere(Au/In_(2)O_(3)-HM).Au/In_(2)O_(3)-NS exhibited the best performance with good CO_(2)conversion of 12.7%,high methanol selectivity of 59.8%,and large space time yield of 0.32 g CH_(3)OH/(hr·gcat)at 300℃.The high performance of Au/In_(2)O_(3)-NS was considered as the presence of Au.It contributes to the creation of more surface oxygen vacancies,which further promoted the CO_(2)adsorption and facilitated CO_(2)activation to form the formate intermediates towards methanol.This work clearly suggests that the activity of In_(2)O_(3)catalyst can be effective enhanced by structure engineering and Au decorating.

关键词： CO_(2)hydrogenation Methanol Au/In_(2)O_(3) Morphology Oxygen vacancies

Drug-Target Interactions Prediction Based on Signed Heterogeneous Graph Neural Networks

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Chinese Journal of Electronics 2024年第1期33卷 231-244页

作者： Ming CHEN Yajian JIANG Xiujuan LEI Yi PAN Chunyan JI Wei JIANG college of Information science and engineering Hunan Normal University School of Computer science Shaanxi Normal University Faculty of Computer science and control engineering Shenzhen Institute of Advanced TechnologyChinese Academy of Sciences Computer science Department BNU-HKBU United International College

Drug-target interactions(DTIs) prediction plays an important role in the process of drug discovery.Most computational methods treat it as a binary prediction problem, determining whether there are connections between drugs and targets while ignoring relational types information. Considering the positive or negative effects of DTIs will facilitate the study on comprehensive mechanisms of multiple drugs on a common target, in this work, we model DTIs on signed heterogeneous networks, through categorizing interaction patterns of DTIs and additionally extracting interactions within drug pairs and target protein pairs. We propose signed heterogeneous graph neural networks(SHGNNs), further put forward an end-to-end framework for signed DTIs prediction, called SHGNN-DTI,which not only adapts to signed bipartite networks, but also could naturally incorporate auxiliary information from drug-drug interactions(DDIs) and protein-protein interactions(PPIs). For the framework, we solve the message passing and aggregation problem on signed DTI networks, and consider different training modes on the whole networks consisting of DTIs, DDIs and PPIs. Experiments are conducted on two datasets extracted from Drug Bank and related databases, under different settings of initial inputs, embedding dimensions and training modes. The prediction results show excellent performance in terms of metric indicators, and the feasibility is further verified by the case study with two drugs on breast cancer.

关键词： Drug-target interactions Signed heterogeneous network Link sign prediction Graph neural networks