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Conversion of Lignin into Porous Carbons for High-Performance Supercapacitors via Spray Drying and KOH Activation: Structure-Properties Relationship and Reaction Mechanism

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Journal of Renewable Materials 2024年第7期12卷 1207-1218页

作者： Shihao Feng Qin Ouyang Jing huang Xilin Zhang Zhongjun Ma Kun Liang Qing huang Zhejiang Key Laboratory of Data-Driven High-Safety Energy Materials and Applications Ningbo Key Laboratory of Special Energy Materials and ChemistryNingbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo315201China Engineering Laboratory of Advanced Energy Materials Qianwan Institute of CNITECHNingbo315336China School of Physics Henan Normal UniversityXinxiang453007China School of Environment Henan Normal UniversityXinxiang453007China

Lignin-derived porous carbons have emerged as promising electrode materials for ***,the challenge remains in designing and controlling their structure to achieve ideal electrochemical performance due to the complex molecular structure of lignin and its intricate chemical reactions during the activation *** this study,three porous carbons were synthesized from lignin by spray drying and chemical activation with vary-ing KOH *** speciﬁc surface area and structural order of the prepared porous carbon continued to increase with the increase of the KOH ***-mass spectrometry(TG-MS)was employed to track the molecular fragments generated during the pyrolysis of KOH-activated lignin,and the mechanism of the thermochemical conversion was *** the thermochemical conversion of lignin,KOH facili-tated the removal of H2 and CO,leading to the formation of not only more micropores and mesopores,but also more ordered carbon *** pore structure exhibited a greater impact than the carbon structure on the electrochemical performance of porous *** optimized porous carbon exhibited a capacitance of 256 F g-1 at a current density of 0.2 A g-1,making it an ideal electrode material for high-performance supercapacitors.

关键词： Lignin porous carbon KOH activation mechanism supercapacitor

Rational designed ZIF-8@PDA@PDMS composite sponge for efficient and sustainable particulate matter filtering under harsh environment

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Particuology 2023年第5期76卷 141-150页

作者： Yukui Gou Yuanye Hao Weilong Cai Jianying huang Yuekun Lai College of Chemical Engineering Fuzhou UniversityFuzhou350116China Qingyuan Innovation Laboratory Quanzhou362801China

Particulate matter(PM)is a significant danger to both environment and human *** the development of a series of air filters,they do not work well in harsh environment such as high tem-perature,high humidity or long-time *** make a three-dimensional(3D)particle capture de-vice,a sacrificial template approach was used to manufacture polydimethylsiloxane(PDMS)sponge,and then zeolite imidazole framework-8(ZIF-8)was grown in situ on the 3D network of PDMS *** removal efficiency of PM_(2.5)or PM10 is greater than 99.8%because of the high specific surface area and porous network structure of PDMS sponge,as well as the large number of metal sites of *** addition,the sponge filter has long-term filtration stability and still achieves excellent performance after 65 h of *** composite sponge can adapt to harsh environments such as high temperature(250℃)and high humidity(90%RH).Composite sponge filter has a regular shape,and it may be customized to any shape as *** study provides a new idea for designing 3D high-efficiency air filters that can adapt to harsh environments.

关键词： PDMS sponge ZIF-8 Particle capture High temperature Stability

Synthesis of Mn/Co-MOF for effective removal of U(VI) from aqueous solution

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Particuology 2023年第1期72卷 134-144页

作者： Yuming Xie Lijiao Fan Wenbing Liu Qin Zhang Guolin huang State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang330013China

Ultrasound-assisted synthesis of Mn/Co-MOF nanomaterial was used to capture uranium from aqueous solutions. Tests of Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared spectra (FT-IR), Zeta potential analysis, thermogravimetric analysis (TGA), and X-ray diffraction (XRD) suggest that cobalt ions were replaced partially by manganese ions to generate MOF during the synthesis process and form manganous oxide particles loaded on the surface of Mn/Co-MOF. The optimal immobilization conditions of U(VI) were systematically studied by solution pH, kinetic, contact time and preparatory uranium concentration. XPS spectroscopy analysis indicated that the chelation of imidazole ring to uranium and Mn3O4 possibly played a certain role in the adsorption process. The results indicate that the adsorption isotherms of the Mn/Co-MOF for uranium suit Langmuir isotherm model (maximum adsorption capacity were 763.36 mg/g). Furthermore, the adsorption kinetics of Mn/Co-MOF match comfortably with the pseudo-second-order kinetic model.

关键词： Adsorption Uranium Mn/Co-MOF Kinetic

Smart Attendance System Based on Frequency Distribution Algorithm with Passive RFID Tags

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Tsinghua Science and Technology 2020年第2期25卷 217-226页

作者： Qianwen Miao Fu Xiao Haiping huang Lijuan Sun Ruchuan Wang School of Computer Nanjing University of Posts and TelecommunicationsNanjing 210046China Department of Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing 210046China

Staff attendance information has always been an important part of corporate ***,some opportunistic employees may consign others to punch their time cards,which hampers the authenticity of attendance and effectiveness of record ***,it is necessary to develop an innovative anti-cheating system for office ***-Frequency IDentification(RFID)offers new solutions to solve such problems because of its strong anti-interference capability and *** this paper,we present a smart attendance system that extracts distinguishable phase characteristics of individuals to enable recognition of various targets.A frequency distribution histogram is extracted as a fingerprint for recognition and the K-means clustering method is utilized for more fine-grained recognition of targets with similar *** with traditional attendance mechanisms,RFID-based attendance systems are based on living biological characteristics,which greatly reduces the possibility of false *** evaluate the performance of our system,we conducted extensive *** results of which demonstrate the efficiency and accuracy of our system with an average accuracy of 92%.Moreover,the system evaluation shows that our design is robust against differences in the clothing worn and time of day,which further verifies the successful performance of our system.

关键词： frequency distribution Radio-Frequency IDentification(RFID) office attendance K-means clustering

A Combined Reinforcement Learning and Model Predictive Control for Car-Following Maneuver of Autonomous Vehicles

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Chinese Journal of Mechanical Engineering 2023年第3期36卷 315-325页

作者： Liwen Wang Shuo Yang Kang Yuan Yanjun huang Hong Chen School of Automotive Studies Tongji UniversityShanghai 201804China Shanghai Institute of Intelligent Science and Technology Tongji UniversityShanghai 201804China College of Electronic and Information Engineering Tongji UniversityShanghai 201804China

Model predictive control is widely used in the design of autonomous driving ***,its parameters are sensitive to dynamically varying driving conditions,making it difficult to be implemented into *** a result,this study presents a self-learning algorithm based on reinforcement learning to tune a model predictive ***,the proposed algorithm is used to extract features of dynamic traffic scenes and adjust the weight coefficients of the model predictive *** this method,a risk threshold model is proposed to classify the risk level of the scenes based on the scene features,and aid in the design of the reinforcement learning reward function and ultimately improve the adaptability of the model predictive controller to real-world *** proposed algorithm is compared to a pure model predictive controller in car-following *** to the results,the proposed method enables autonomous vehicles to adjust the priority of performance indices reasonably in different scenarios according to risk variations,showing a good scenario adaptability with safety guaranteed.

关键词： Model predictive control Reinforcement learning Autonomous vehicles

Discovering Association Rules with Graph Patterns in Temporal Networks

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Tsinghua Science and Technology 2023年第2期28卷 344-359页

作者： Chu huang Qianzhen Zhang Deke Guo Xiang Zhao Xi Wang Science and Technology on Information Systems Engineering Laboratory College of Systems EngineeringNational University of Defense TechnologyChangsha 410073China

Discovering regularities between entities in temporal graphs is vital for many real-world applications(e.g.,social recommendation,emergency event detection,and cyberattack event detection).This paper proposes temporal graph association rules(TGARs)that extend traditional graph-pattern association rules in a static graph by incorporating the unique temporal information and *** introduce quality measures(e.g.,support,confidence,and diversification)to characterize meaningful TGARs that are useful and *** addition,the proposed support metric is an upper bound for alternative metrics,allowing us to guarantee a superset of *** extend conventional confidence measures in terms of maximal occurrences of *** diversification score strikes a balance between interestingness and *** the problem is NP-hard,we develop an effective discovery algorithm for TGARs that integrates TGARs generation and TGARs selection and shows that mining TGARs is feasible over a temporal *** propose pruning strategies to filter TGARs that have low support or cannot make top-k as early as ***,we design an auxiliary data structure to prune the TGARs that do not meet the constraints during the TGARs generation process to avoid conducting repeated subgraph matching for each extension in the search *** experimentally verify the effectiveness,efficiency,and scalability of our algorithms in discovering diversified top-k TGARs from temporal graphs in real-life applications.

关键词： temporal networks graph association rule subgraph pattern matching graph mining big graphs

Embedding copper nanoparticle-anchored conductive nano-blocks in polyelectrolyte

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Particuology 2013年第6期11卷 748-752页

作者： Qingsong Xu Jianguo Tang Yao Wang Jixian Liu Zhen huang Linjun huang Aihua Li Yuan Wang Laurence A.Belfiore Institute of Hybrid Materials Growing Base for State Key Laboratory of New Fiber and Modern TextileQingdao University Department of Chemical and Biological Engineering Colorado State University

Conductive carbon nanotubes （CNTs） or alternatively polyaniline （PANI） nano-blocks was introduced into aqueous solutions of polyvinyl alcohol （PVA） and copper （II） salt, to assist the reduction of copper （II） ions and the anchoring of the resulting copper nanoparticles onto the conductive blocks. The mixture solutions of nano-blocks, copper （lI） salts and PVA were spin-coated onto the cathode surface, forming swollen cathode films （SCFs）. The copper （II） ions in the film assembled onto the surfaces of the conductive blocks and were then reduced under an appropriate voltage. It is important that the copper nanoparticles grew only on the surfaces of the conductive blocks. PVA which acted as the matrix of the composites played a role in stabilizing the resulting copper nanoparticles. Morphologies of these polymeric composite films were studied by various characterization methods. Moreover, the mechanism of migration of copper （II） ions, the formation of these polymeric composites, and the overall procedure were investigated in detail.

关键词： Copper nanoparticles Carbon nanotubes Polyaniline Polyelectrolyte

A Shakedown Strength Based Parametric Optimization Technique and Its Application on an Airtight Module

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Chinese Journal of Mechanical Engineering 2022年第4期35卷 139-151页

作者： Songhua huang Yugong Xu Lele Zhang Geng Chen Feng Liu School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China National International Science and Technology Cooperation Base on Railway Vehicle Operation Beijing Jiaotong UniversityBeijing 100044China Beijing Institute of Spacecraft System Engineering Academy of Space TechnologyBeijing 100094China

In aerospace engineering,design and optimization of mechanical structures are usually performed with respect to elastic *** causing insufcient use of the material,such design concept fails to meet the ever growing needs of the light weight *** remedy this problem,in the present study,a shakedown theory based numerical approach for performing parametric optimization is *** this approach,strength of the structure is measured by its shakedown limit calculated from the direct *** numerical method developed for the structural optimization consists of nested loops:the inner loop adopts the interior point method to solve shakedown problems pertained to fxed design parameters,while the outer loop employs the genetic algorithm to fnd optimal design parameters leading to the greatest shakedown *** method established is frst verifed by the classic plate-with-a-circular-hole example,and after that it is applied to an airtight module for determining few key design *** carefully analyzing results generated during the optimization process,it is convinced that the approach can become a viable means for designing similar aerospace structures.

关键词： Parametric optimal design Shakedown analysis Direct method(DM) Genetic algorithm

Experimental investigation of unsteady attached cavitating flow induced pressure fluctuation

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Journal of Hydrodynamics 2022年第1期34卷 31-42页

作者： Hou-sheng Zhang Guang-hao Chen Qin Wu Biao huang School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081China AVIC Jincheng Nanjing Engineering Institute of Aircraft System Nanjing211106China

This paper experimentally investigates the pressure fluctuation induced by the unsteady attached cavitating flow, with special focus on the quasi-periodic cloud cavitation. A simultaneous sampling method is adopted for the synchronous measurement of the wall pressure signals and the cavitating flow images in a convergent-divergent channel. The results show that the pressure fluctuation is composed of three parts, the flow noise, the low-frequency fluctuation, and the cavity collapse induced impulse, and the pressure evolution of the quasi-periodic cloud cavitation is well consistent with the cavitation evolution. The statistical analysis of the pressure fluctuation shows that, when σ > 1.01, the probability density function (PDF) is nearly in the normal distribution, implying the randomness of the pressure fluctuation, when 0.84 1.01, when σ < 0.84, the PDF becomes narrow and asymmetric. In addition, the variance and the average value of the pressure indicate that the fluctuation intensity increases downstream along the cavity and reaches the maximum at the cavity closure and it also increases with the decrease of the cavitation number. The spectral analysis shows that the low-frequency pressure fluctuations mainly consist of two dominant components, the cavity shedding induced fluctuation and the lock-in fluctuation. The cavity shedding induced frequency decreases with the decrease of the cavitation number but the lock-in frequency is kept nearly constant. According to the spectral analysis of the cavity area fluctuation and the modal analysis of the flow system, the lock-in is possibly caused when the fluctuation frequency of the cavity volume approaches the natural frequency of the flow system.

关键词： Cavitation pressure fluctuation statistical features lock-in phenomenon