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The Estimation of the Higher Heating Value of Biochar by Data-Driven Modeling

Journal of Renewable Materials 2022年第6期10卷 1555-1574页

作者： Jiefeng Chen Lisha Ding Pengyu Wang Weijin Zhang Jie Li Badr A.Mohamed Jie Chen Songqi leng Tonggui Liu lijian leng Wenguang Zhou Key Laboratory of Poyang Lake Environment and Resource Utilization Ministry of Education and School of ResourcesEnvironmental&Chemical EngineeringNanchang UniversityNanchangChina School of Energy Science and Engineering Central South UniversityChangshaChina Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore Department of Agricultural Engineering Cairo UniversityGizaEgypt

Biomass is a carbon-neutral renewable energy *** produced from biomass pyrolysis exhibits preferable characteristics and potential for fossil fuel *** time-and cost-saving,it is vital to establish predictive models to predict biochar ***,limited studies focused on the accurate prediction of HHV of biochar by using proximate and ultimate analysis results of various ***,the multi-linear regression(MLR)and the machine learning(ML)models were developed to predict the measured HHV of biochar from the experiment data of this *** detail,52 types of biochars were produced by pyrolysis from rice straw,pig manure,soybean straw,wood sawdust,sewage sludge,Chlorella Vulgaris,and their mixtures at the temperature ranging from 300 to 800℃.The results showed that the co-pyrolysis of the mixed biomass provided an alternative method to increase the yield of biochar *** contents of ash,fixed carbon(FC),and C increased as the incremental pyrolysis temperature for most *** Pearson correlation(r)and relative importance analysis between HHV values and the indicators derived from the proximate and ultimate analysis were carried out,and the measured HHV was used to train and test the MLR and the ML ***,ML algorithms,including gradient boosted regression,random forest,and support vector machine,were also employed to develop more widely applicable models for predicting HHV of biochar from an expanded dataset(total 149 data points,including 97 data collected from the published literature).Results showed HHV had strong correlations(|r|>0.9,p*** ML models showed better performance with test R^(2)around 0.95(random forest)and 0.97–0.98 before and after adding extra data for model construction,*** importance analysis of the ML models showed th

关键词： Biochar higher heating value machine learning prediction proximate analysis ultimate analysis

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Selective preparation for biofuels and high value chemicals based on biochar catalysts

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Frontiers in Energy 2023年第5期17卷 635-653页

作者： Hui LI Changlan HOU Yunbo ZHAI Mengjiao TAN Zhongliang HUANG Zhiwei WANG lijian leng Peng LIU Tingzhou LEI Changzhu LI State Key Laboratory of Utilization of Woody Oil Resource Hunan Academy of ForestryChangsha 410004China College of Environmental Science and Engineering Hunan UniversityChangsha 410082China School of Environmental Engineering Henan University of TechnologyZhengzhou 450001China School of Energy Science and Engineering Central South UniversityChangsha 410083China National-Local Joint Engineering Research Center of Biomass Refining and High-Quality Utilization Institute of Urban and Rural MiningChangzhou UniversityChangzhou 213164China

The reuse of biomass wastes is crucial toward today’s energy and environmental crisis,among which,biomass-based biochar as catalysts for biofuel and high value chemical production is one of the most clean and economical *** this paper,the recent advances in biofuels and high chemicals for selective production based on biochar catalysts from different biomass wastes are critically *** topics mainly include the modification of biochar catalysts,the preparation of energy products,and the mechanisms of other high-value *** biochar catalysts can enhance the yield of biofuels and higher-value ***,the feedstock and reaction conditions of biochar catalyst,which affect the efficiency of energy products,have been the focus of recent *** studies based on biochar catalysts will be helpful to the controlled ***,the design and advancement of the biochar catalyst based on mechanism research will be beneficial to increase biofuels and the conversion efficiency of chemicals into *** advanced design of biochar catalysts and optimization of operational conditions based on the biomass properties are vital for the selective production of high-value chemicals and *** paper identifies the latest preparation for energy products and other high-value chemicals based on biochar catalysts progresses and offers insights into improving the yield of high selectivity for products as well as the high recyclability and low toxicity to the environment in future applications.

关键词： biomass biochar catalysts biofuels high chemicals

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Machine learning predicting and engineering the yield,N content,and specific surface area of biochar derived from pyrolysis of biomass

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Biochar 2022年第1期4卷 134-151页

作者： lijian leng Lihong Yang Xinni Lei Weijin Zhang Zejian Ai Zequn Yang Hao Zhan Jianping Yang Xingzhong Yuan Haoyi Peng Hailong Li School of Energy Science and Engineering Central South UniversityChangsha 410083HunanPeople’s Republic of China. College of Environmental Science and Engineering Hunan UniversityChangsha 410083HunanPeople’s Republic of China

Biochar produced from pyrolysis of biomass has been developed as a platform carbonaceous material that can be used in various *** specific surface area(SSA)and functionalities such as N-containing functional groups of biochar are the most significant properties determining the application performance of biochar as a carbon material in various areas,such as removal of pollutants,adsorption of CO_(2)and H2,catalysis,and energy *** biochar with preferable SSA and N functional groups is among the frontiers to engineer biochar *** study attempted to build machine learning models to predict and optimize specific surface area of biochar(SSA-char),N content of biochar(N-char),and yield of biochar(Yield-char)individually or simultaneously,by using elemental,proximate,and biochemical compositions of biomass and pyrolysis conditions as input *** predictions of Yield-char,N-char,and SSA-char were compared by using random forest(RF)and gradient boosting regression(GBR)*** outperformed RF for most *** input parameters included elemental and proximate compositions as well as pyrolysis conditions,the test R^(2) values for the single-target and multi-target GBR models were 0.90-0.95 except for the two-target prediction of Yield-char and SSA-char which had a test R^(2) of 0.84 and the three-target prediction model which had a test R^(2) of *** indicated by the Pearson correlation coefficient between variables and the feature importance of these GBR models,the top influencing factors toward predicting three targets were specified as follows:pyrolysis temperature,residence time,and fixed carbon for Yield-char;N and ash for N-char;ash and pyrolysis temperature for *** effects of these parameters on three targets were different,but the trade-offs of these three were balanced during multi-target ML prediction and *** optimum solutions were then experimentally verified,which opens a new way for de

关键词： Specific surface area Nitrogen Biochar Pyrolysis Machine learning

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A solution using only electromagnetic coils for relative pose control in satellite docking

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Chinese Journal of Aeronautics 2024年第3期37卷 258-281页

作者： Guangzheng RUAN lijian WU Bo WANG Yaobing WANG Runqi HAN College of Electrical Engineering Zhejiang UniversityHangzhou 310012China Beijing Institute of Spacecraft System Engineering Beijing 100094China

This paper proposes an electromagnetic coil topology and its control strategy,which can be incorporated into the electromagnetic docking device to achieve relative pose control in satellite *** target satellite has a main coil;the chaser satellite possesses a main coil of the same size accompanied by six and four evenly arranged secondary coils inside and outside the main coil,*** coil on the target satellite is DC energized,while the currents in the coils of the chaser satellite are *** remove the coupling between the pitch/yaw torque and translational force,the internal and external secondary coils of the chaser satellite interact with the main coil of the target satellite to perform the control of relative pitch/yaw and relative translation,respectively,so relative pose control can be *** torque and force vectors exerted by the secondary coils of the chaser satellite are synthesized onto the pitch and yaw axes of the body *** to their spatial composition relationship,the formulas are proposed,which obtain the magnetic moment vectors of the coils from the set torques and *** controllers regulating pitch/yaw,translation,and distance utilize a three-loop cascaded structure that consists of an outer position loop,a middle velocity loop and an inner current *** control strategy is verified by dynamics simulation.

关键词： Electromagnetic docking 6 degree of freedom Relative pose control Coil array Far field model Motion decoupling

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A Numerical Study on the Effect of the Backflow Hole Position on the Performances of a Self-Priming Pump

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Fluid Dynamics & Materials Processing 2024年第5期20卷 1103-1122页

作者： Dongwei Wang lijian Cao Weidong Wang Jiajun Hu School of Energy and Power Engineering Lanzhou University of TechnologyLanzhou730050China Sanlian Pump Industry Co. Ltd.Ma’anshan243000China

A self-priming pump is a centrifugal pump that has the ability to prime itself. Typically, its performance dependson the configuration of its reflux hole. In this study, the ANSYS FLUENT software is used to investigate the effectsof three different radial positions of the reflux hole on gas-liquid two-phase distribution, pressure pulsation, andimp during self-priming. The research results indicate that: (1) The effective channel size for the reflux liquid toenter the volute varies depending on the location of the reflux hole. The effect of the impeller rotation on thereflux liquid becomes more obvious as the setting distance of the reflux aperture decreases. (2) The position ofthe reflux hole significantly affects the gas phase mass fraction inside the impeller, resulting in a significant reductionin the time it takes for the mass fraction to exceed 80%. (3) The position of the reflux hole significantly affectsthe average pressure on each monitoring surface. (4) Placing the reflux hole at a excessively distant radial distancecan result in an excessive vertical component. (5) The self-priming performance of the pump can be improved tosome extent by placing the return hole at a small radial distance.

关键词： Self-priming pump self-priming time numerical calculation gas-liquid two-phase flow

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The Potential Game-Changer:A Concept-to-Proof Study on D:A Heterojunction-Free Organic Photovoltaics

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Chinese Journal of Chemistry 2024年第3期42卷 252-258页

作者： lijian Zuo Sae Byeok Jo Xueliang Shi Francis Lin Alex Jen State Key Laboratory of Silicon and Advanced Semiconductor Materials MOE Key Laboratory of Macromolecular Synthesis and FunctionalizationDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhouZhejiang310058 China Department of Materials Science and Engineering University of WashingtonSeattleWAUSA School of Chemical Engineering Sungkyunkwan University (SKKU)Suwon16419 Republic of Korea School of Chemistry and Molecular Engineering East China Normal UniversityShanghai200062 China Department of Materials Science and Engineering City University of Hong KongKowloonHong KongChina Department of Chemistry City University of Hong KongKowloonHong KongChina Hong Kong Institute for Clean Energy Hong KongChina

Since 1986,the donor-acceptor (D:A) heterojunction has been regarded a necessity for high-efficiency organic photovoltaics (OPVs),due to its unique advantage in compensating the intrinsic limitations of organic semiconductors,such as high exciton binding energy and poor ambipolar charge mobility. While this adversely causes tremendous non-radiative charge recombination and instability issues,which currently become the most critical limits for commercialization of OPVs. Here,we present a concept-to-proof study on the potential of D:A heterojunction free OPV by taking advantage of recent progress of non-fullerene acceptors. First,we demonstrate that the “free carriers” can be spontaneously generated upon illumination in an NFA,i.e.,the 6TIC-4F single layer. Second,the 6TIC-4F layer also exhibits good ambipolar charge transporting property. These exceptional characteristics distinguish it from the traditional organic semiconductors,and relieve it from the reliance of D:A heterojunction to independently work as active layer. As a result,the subsequent OPV by simply sandwiching the 6TIC-4F layer between the cathode and anode yields a considerably high power conversion efficiency ~1%. Moreover,we find the D:A heterojunction free device exhibits two order of magnitude higher electroluminescence quantum efficiency and significantly reduced VOC loss by 0.16 eV compared to those of the D:A BHJ structure,validating its promise for higher efficiency in the future. Therefore,our work demonstrates the possibility of using D:A heterojunction-free device structure for high performance,that can potentially become the next game changer of OPV.

关键词： Organic solar cells Spontaneous charge generation Ambipolar charge transport Charge recombination Perovskite-like organic semiconductor Schottky-junction structure Single component

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Deep Reinforcement Learning Based Resource Allocation for Fault Detection with Cloud Edge Collaboration in Smart Grid

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1220-1230页

作者： Qiyue Li Yadong Zhu Jinjin Ding Weitao Li Wei Sun lijian Ding Hefei University of Technology Engineering Technology Research Center of Industrial Automation Hefei 230009China Electric Power Research Institute of State Grid Anhui Electric Power Co. Ltd.Hefei 230000China Hefei University of Technology Hefei 230009China IEEE CSEE

Real-time fault detection is important for operation of smart *** has become a trend of future development to design an anomaly detection system based on deep learning by using the powerful computing power of the ***,delay of Internet transmission is large,which may make the delay time of detection and transmission go beyond the ***,the edge-based scheme may not be able to undertake all data detection tasks due to limited computing resources of edge ***,we propose a cloud-edge collaborative smart grid fault detection system,next to which edge devices are placed,and equipped with a lightweight neural network with different precision for fault *** addition,a sub-optimal and realtime communication and computing resource allocation method is proposed based on deep reinforcement *** method greatly speeds up solution time,which can meet the requirements of data transmission delay,maximize the system throughput,and improve communication *** results show the scheme is superior in transmission delay and improves real-time performance of the smart grid detection system.

关键词： Cloud-edge collaboration communication delay deep reinforcement learning fault detection smart grid

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Laser ablation mechanism and performance of glass fiber-reinforced phenolic composites:An experimental study and dual-scale modelling

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Chinese Journal of Aeronautics 2024年第8期37卷 470-485页

作者： Ran BI Pengfei SHEN Longyu ZHU Zhengzheng MA Chuyang LUO Yongfeng LI lijian PAN Shanghai Key Laboratory of Lightweight Composite Donghua UniversityShanghai 201620China Shanghai High Performance Fibers and Composites Center(Province-Ministry Joint) Center for Civil Aviation CompositesDonghua UniversityShanghai 201620China AVIC Composite Corporation Ltd Beijing 101300China

Both experimental and simulation approaches were employed to investigate the laser ablation mechanism and performances of Glass Fiber Reinforced Phenolic Composites(GFRP).During the ablation process,the difference in thermal conductivities of the glass fibers and the resin matrix as well as their discrepant physical and chemical reactions form a conical ablation *** formation of a residual carbon layer effectively mitigates the ablation rate in the thickness direction.A higher power density results in a faster ablation rate,while a longer irradiation time leads to a larger ablation pit *** account for the variation in thermal conductivity between the fiber and resin,a macro-mesoscale model was developed to differentiate the matrix from the fiber *** element analysis revealed that laser irradiation leads to phenolic decomposition,glass fiber melting vaporization,and residual carbon skeleton *** dual-scale model exhibits precise prediction capabilities concerning the laser ablation process of GFRP,and its accuracy is confirmed through the comparison of simulation and experimental results for the GFRP laser ablation *** model provides a feasible method for performance evaluation and lifetime prediction of GFRP subjected to continuous wave laser irradiation.

关键词： Polymer-matrix composites Continuous-wave laser Microstructural analysis Ablation mechanism Finite element method

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轧钢油泥窑内燃煤中黏结行为模拟及结圈物特性

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洁净煤技术 2022年第10期28卷 47-53页

作者：谢斌杨建平冷立健李海龙中南大学能源科学与工程学院湖南长沙410012

为明确轧钢油泥在回转窑内中的结圈原因和结圈特性,采用一种氧化球团回转窑结圈特性评价方法,对轧钢油泥在不同工况下的黏结行为进行研究,并通过灰熔融温度、粉末X射线荧光光谱(XRF)、粉末X射线衍射光谱(XRD)、块状扫描电子显微镜(SEM)... 详细信息

为明确轧钢油泥在回转窑内中的结圈原因和结圈特性,采用一种氧化球团回转窑结圈特性评价方法,对轧钢油泥在不同工况下的黏结行为进行研究,并通过灰熔融温度、粉末X射线荧光光谱(XRF)、粉末X射线衍射光谱(XRD)、块状扫描电子显微镜(SEM)和能谱分析仪(EDS)对结圈物的物相组成和形貌进行表征测试。以结圈指数和黏附指数为评价指标,考察了焙烧温度和焙烧时间对轧钢油泥在耐火砖表面黏结性能的影响。研究表明轧钢油泥的结圈指数和黏附指数随焙烧时间和焙烧温度的增加而增加;1 150~1 250℃时增长速度最快,与实际回转窑中主要结圈物情况相吻合,间接证实了该方法对评价结圈行为的适用性。结果表明,结圈物的矿相晶粒粗大、结构不均匀、空隙较多,单个颗粒晶体分布明显且表面主要呈熔蚀状,整体上多晶粒关联性的结晶程度不高。轧钢油泥回转窑结圈主要是Fe_(2)O_(3)固相固结反应,余下的少量杂质生成了低熔点物质,一定程度上促进了铁晶粒的迁移,加剧了结圈行为,这与XRD检测到的结圈物的物相主要是赤铁矿,其次是磁铁矿等铁氧化物和低熔点物质相吻合。灰熔融温度测试中结圈物的变形温度和软化温度总体上升,进一步证明氧化环境下二次生成的Fe_(2)O_(3)和生成的Fe_(2)O_(3)再结晶作用使结圈物强度更高且不易破碎。

关键词：轧钢油泥回转窑结圈特性形成机理低熔点物质

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光量子精密测量研究进展(特邀)

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中国激光 2024年第1期51卷 354-368页

作者：王犇张利剑南京大学现代工程与应用科学学院江苏南京210023 智能光传感与调控技术教育部重点实验室江苏南京210023 人工微结构科学与技术协同创新中心江苏南京210023 南京大学固体微结构物理国家重点实验室江苏南京210023

量子精密测量作为当代量子力学的主要应用方面之一,近些年来一直是量子科技的重要研究和发展方向。量子精密测量的主要研究目标是针对物理系统中的未知参数,利用量子资源进行量子增强测量,以提升参数测量精度。与其他物理系统相比,光子... 详细信息

量子精密测量作为当代量子力学的主要应用方面之一,近些年来一直是量子科技的重要研究和发展方向。量子精密测量的主要研究目标是针对物理系统中的未知参数,利用量子资源进行量子增强测量,以提升参数测量精度。与其他物理系统相比,光子系统具有相干时间长、不易受到环境干扰等优越性,因而常被用作量子信息处理的载体。以光子为基础的传感器提升传感精度是光量子精密测量的主要任务。介绍了量子精密测量的一般性原理,给出参数估计的量子极限精度下界。同时,介绍了目前光量子精密测量的理论与实验研究进展以及相应的挑战。

关键词：量子光学量子精密测量参数估计海森堡极限传感

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