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Low-temperature graphitization of lignin via Co-assisted electrolysis in molten salt

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Green Energy & Environment 2024年第9期9卷 1449-1458页

作者： Shijie Li Wei-Li Song Xue Han Qingqing Cui Yan-li Zhu Shuqiang Jiao institute of Advanced Structure technology Beijing Institute of Technology State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing State Key Laboratory of Explosion Science and technology Beijing Institute of Technology

The ever-growing energy demand and environmental issues have stimulated the development of sustainable energy ***,an efficient and environmentally friendly electrochemical transformation technology was proposed to prepare highly graphitized carbon materials from an abundant natural resource-lignin （LG）.The preparation process mainly includes pyrolytic carbonization of raw LG material and electrochemical conversion of amorphous carbon ***,with the assistance of Co catalyst,the graphitization degree of the products was significantly improved,in which the mechanism was the removal of heteroatoms in LG and the rearrangement of carbon atoms into graphite ***,tunable microstructures （nanoflakes） under catalytic effects could also be observed by controlling the electrolytic *** with the products CN1 （without catalyst） and CN5 （with 10%catalyst）,the specific surface area are 158.957 and202.246 m2g-1,*** used as the electrode material for lithium-ion batteries,CN5 delivered a competitive specific capacity of～350 m Ah g-1（0.5 C） compared with commercial *** strategy proposed in this work provides an effective way to extract value-added graphite materials from lignin and can be extended to the graphitization conversion of any other amorphous carbon precursor materials.

关键词： Lignin Graphitic carbon Electrochemical conversion Lithium-ion batteries

Enhancing Software Effort Estimation:A Hybrid Model Combining LSTM and Random Forest

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Journal of Harbin institute of technology(New Series) 2024年第4期31卷 42-51页

作者： Badana Mahesh Mandava Kranthi Kiran Department of Computer Science and Engineering GITAM Deemed to be UniversityVishakhapatnam 561203India Department of Computer Science and Engineering Anil Neerukonda Institute of Technology&SciencesVishakhapatnam 531162India

Effort estimation plays a crucial role in software development projects,aiding in resource allocation,project planning,and risk *** estimation techniques often struggle to provide accurate estimates due to the complex nature of software *** recent years,machine learning approaches have shown promise in improving the accuracy of effort estimation *** study proposes a hybrid model that combines Long Short-Term Memory(LSTM)and Random Forest(RF)algorithms to enhance software effort *** proposed hybrid model takes advantage of the strengths of both LSTM and RF *** evaluate the performance of the hybrid model,an extensive set of software development projects is used as the experimental *** experimental results demonstrate that the proposed hybrid model outperforms traditional estimation techniques in terms of accuracy and *** integration of LSTM and RF enables the model to efficiently capture temporal dependencies and non-linear interactions in the software development *** hybrid model enhances estimation accuracy,enabling project managers and stakeholders to make more precise predictions of effort needed for upcoming software projects.

关键词： software effort estimation hybrid model ensemble learning LSTM temporal dependencies non⁃linear relationships

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Fast Cross-Platform Binary Code Similarity Detection Framework Based on CFGs Taking Advantage of NLP and Inductive GNN

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Chinese Journal of Electronics 2024年第1期33卷 128-138页

作者： Jinxue PENG Yong WANG Jingfeng XUE Zhenyan LIU School of Computer Science and technology Beijing Institute of Technology

Cross-platform binary code similarity detection aims at detecting whether two or more pieces of binary code are similar or not. Existing approaches that combine control flow graphs(CFGs)-based function representation and graph convolutional network(GCN)-based similarity analysis are the best-performing ones. Due to a large amount of convolutional computation and the loss of structural information, the use of convolution networks will inevitably bring problems such as high overhead and sometimes inaccuracy. To address these issues, we propose a fast cross-platform binary code similarity detection framework that takes advantage of natural language processing(NLP)and inductive graph neural network(GNN) for basic blocks embedding and function representation respectively by simulating extracting structural features and temporal features. GNN’s node-centric and small batch is a suitable training way for large CFGs, it can greatly reduce computational overhead. Various NLP basic block embedding models and GNNs are evaluated. Experimental results show that the scheme with long short term memory(LSTM)for basic blocks embedding and inductive learning-based Graph SAGE(GAE) for function representation outperforms the state-of-the-art works. In our framework, we can take only 45% overhead. Improve efficiency significantly with a small performance trade-off.

关键词： Training Semantics Process control Binary codes Feature extraction Natural language processing Graph neural networks

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Prescribed-time leader-following consensus of linear multi-agent systems by bounded linear time-varying protocols

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Science China(Information Sciences) 2024年第1期67卷 140-153页

作者： Kai ZHANG Bin ZHOU Xuefei YANG Guangren DUAN Center for Control Theory and Guidance technology Harbin Institute of Technology

This paper considers the prescribed-time leader-following consensus problem of input-constrained linear multi-agent systems under generally directed communication topology in two cases:the Laplacian matrix related to the entire communication topology between agents is either known or *** particular,the consensus problem for the former case is solved by a novel bounded linear time-varying(LTV) protocol,where the feedback gain is formulated by the parametric Lyapunov equation and the knowledge of the Laplacian ***,by utilizing a distributed observer,a fully bounded LTV protocol is proposed for the latter *** should be noted that,compared with the existing results,the system under consideration is more general,the designed protocols are linear,and the consensus problem is accomplished even in a fully distributed ***,the effectiveness of the proposed approach is verified by a numerical example.

关键词： leader-following consensus time-vary feedback prescribed-time control fully distributed consensus

Prescribed time control based on the periodic delayed sliding mode surface without singularities

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Science China(Information Sciences) 2024年第7期67卷 256-270页

作者： Bin ZHOU Yi DING Kang-Kang ZHANG Guang-Ren DUAN Center for Control Theory and Guidance technology Harbin Institute of Technology

In this paper, nonsingular prescribed-time control is studied based on periodic delayed sliding mode surfaces. Different from the existing sliding mode control, where either singularity problems may appear or the convergence time depends on the initial state, the proposed sliding mode control approaches can achieve prescribed-time convergence without singularity. The proposed nonsingular sliding mode control approaches can be applied to both second-order and high-order nonlinear systems with prescribed-time convergence. As applications of the proposed sliding mode control approaches, the control of hypersonic vehicle systems is revisited. Numerical simulations on the nonlinear model of the hypersonic vehicle system show the effectiveness of the proposed methods.

关键词： prescribed-time control smooth periodic delayed feedback sliding mode control high-order nonlinear systems hypersonic vehicle systems

Entropy generation minimization in the Carreau nanofluid flow over a convectively heated inclined plate with quadratic thermal radiation and chemical reaction:A Stefan blowing application

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Propulsion and Power Research 2024年第2期13卷 233-244页

作者： B.Lavanya J.Girish Kumar M.Jayachandra Babu C.S.K.Raju Bander Almutairi Nehad Ali Shah Department of Mathematics Manipal Institute of TechnologyManipal Academy of Higher EducationManipalKarnataka 576104India Department of Mathematics S.V.A Government CollegeSrikalahasti 517644India Department of Mathematics GITAM School of Science(GSS)GITAMBangaloreKarnatakaIndia Department of Mathematics College of ScienceKing Saud UniversityRiyadh 11451Saudi Arabia Department of Mechanical Engineering Sejong UniversitySeoul 05006South Korea

Entropy analysis can help to identify the sources of entropy generation in a heat transfer process more accurately than other methods,such as energy efﬁciency *** is because entropy analysis takes into account the quality of energy as well as its ***-noﬂuids have already been shown to have superior heat transfer characteristics compared to conventionalﬂ*** blowing can further enhance the heat transfer capabilities of nano-ﬂuids by increasing the massﬂux and turbulence at the *** can be beneﬁcial in a wide range of applications,such as heat exchangers,electronic cooling,and solar energy *** convective boundary condition accounts for heat transfer effects,inﬂuencing temperature distribution and the thermal boundary *** on the direction of heat transfer,the convective boundary condition can induce cooling or heating effects on the inclined *** has practical implications for various engineering applications,such as the cooling of electronic devices or heating in industrial *** nanofluids have a wide range of potential applications in heat transfer,energy storage,drug delivery,and food *** research investigates how the presence of Stefan blowing affects the properties of Carreau nanofluid flow across a convectively heated tilted *** and mass transport phenomena are studied using quadratic thermal radiation and chemical reaction *** mathematical model for this work is based on the Buongiorno *** governing equations are converted into a system of ordinary differential equations and then solved using the bvp4c *** parameters such as the mass transfer rate can be visualized using bar *** study’s primary findings are that when the Weissenberg number increases,the velocity rises and the concentration profile declines due to Brownian *** is discovered that,when 0.5≤γ≤3(the inverse porosity parameter),the friction factor declines by 0.34001(

关键词： Thermal radiation BVP4C Stefan blowing Biot number Brownian motion Irreversibilit

A model reduction approach for discrete-time linear time-variant systems with delayed inputs

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Science China(Information Sciences) 2024年第4期67卷 197-217页

作者： Ai-Guo WU Guang-Ren DUAN Yu WANG Jie ZHANG School of Mechanical Engineering and Automation Harbin Institute of Technology(Shenzhen) HIT Wuhu Robot technology Research institute Center for Control Science and technology Southern University of Science and Technology

A model reduction approach is presented for discrete-time linear time-variant input-delayed systems. According to this proposed approach, a dynamical variable is constructed by taking advantage of the current state and historical information of input. It is revealed that the behavior of this dynamical variable is governed by a discrete-time linear delay-free system. It is worth noting that the presented variable transformation does not require the system matrix to be invertible. Based on the reduced delay-free models,stabilizing control laws can be easily obtained for the original delayed system. For the case with a single input delay, the constructed variable is an exact prediction for the future state, and thus the stabilizing control law could be designed by replacing the future state with its prediction. Finally, three discrete-time periodic systems with delayed input are employed to illustrate how to utilize the presented model reduction approaches.

关键词： reduction approach predictor-based feedback time-varying systems delayed input periodic system

Ru-doped functional porous materials for electrocatalytic water splitting

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Nano Research 2024年第3期17卷 982-1002页

作者： Chongao Tian Rui Liu Yu Zhang Wenxiu Yang Bo Wang Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials Advanced Technology Research Institute(Jinan)Advanced Research Institute of Multidisciplinary ScienceSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing institute of technology Library Beijing Institute of TechnologyBeijing 100081China

Electrolytic water splitting(EWS)is an attractive and promising technique for the production of hydrogen ***,the sluggish kinetic rate of hydrogen/oxygen evolution reactions leads to a high overpotential and low energy *** to date,Pt/Ir-based nanocatalysts have become the state-of-the-art EWS catalysts,but disadvantages such as high cost and low earth abundance greatly limit their applications in EWS *** an attractive candidate for the Pt/Ir catalysts,series of Ru-based nanomaterials have aroused much attention for their low price,Pt-like hydrogen bond strength,and high EWS *** particular,Ru-doped functional porous materials have been becoming one of the most representative EWS catalysts,which can not only achieve the dispersion and adjustment for active Ru sites,but also simultaneously solve the problems of mass transfer and catalytic conversion in *** this review,the design and preparation strategies of Ru-doped functional porous materials toward EWS in recent years are summarized,including Ru-doped metal organic frameworks(MOFs),Ru-doped porous organic polymers(POPs),and their ***,detailed structure–activity relationships induced by the tuned geometric/electronic structures of Ru-doped functional porous materials are further depicted in this *** but not least,the challenges and perspectives of Ru-doped functional porous materials catalysts are reasonably proposed to provide fresh ideas for the design of Ru-based EWS catalysts.

关键词： Ru-based catalyst functional porous materials electrolytic water splitting oxygen evolution reaction hydrogen evolution reaction

An ultra-deep TSV technique enabled by the dual catalysis-based electroless plating of combined barrier and seed layers

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Microsystems & Nanoengineering 2024年第3期10卷 409-419页

作者： Yuwen Su Yingtao Ding Lei Xiao Ziyue Zhang Yangyang Yan Zhifang Liu Zhiming Chen Huikai Xie School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijingChina Chongqing institute of Microelectronics and Microsystems Beijing Institute of TechnologyChongqingChina

Silicon interposers embedded with ultra-deep through-silicon vias(TSVs)are in great demand for the heterogeneous integration and packaging of opto-electronic chiplets and microelectromechanical systems(MEMS)*** the cost-effective and reliable manufacturing of ultra-deep TSVs,the formation of continuous barrier and seed layers remains a crucial challenge to ***,we present a novel dual catalysis-based electroless plating(ELP)technique by tailoring polyimide(PI)liner surfaces to fabricate dense combined Ni barrier/seed layers in ultradeep *** additional to the conventional acid catalysis procedure,a prior catalytic step in an alkaline environment is proposed to hydrolyze the PI surface into a polyamide acid(PAA)interfacial layer,resulting in additional catalysts and the formation of a dense Ni layer that can function as both a barrier layer and a seed layer,particularly at the bottom of the deep *** with depths larger than 500μm and no voids are successfully fabricated in this *** fabrication process involves low costs and *** a fabricated 530-μm-deep TSV with a diameter of 70μm,the measured depletion capacitance and leakage current are approximately 1.3 pF and 1.7 pA at 20 V,respectively,indicating good electrical *** proposed fabrication strategy can provide a cost-effective and feasible solution to the challenge of manufacturing ultra-deep TSVs for modern 3D heterogeneous integration and packaging applications.

关键词： properties catalysis alkaline