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On the Riemann–Hilbert problem for the reverse space-time nonlocal Hirota equation with step-like initial data

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Communications in Theoretical Physics 2025年第2期77卷 32-40页

作者： Bei-Bei hu Ling Zhang Zu-Yi Shen Ji Lin School of Mathematics and Finance Chuzhou University Applied Mathematics Research Center Chuzhou University Department of Physics Zhejiang Normal University

In this paper, we use the Riemann–Hilbert(RH) method to investigate the Cauchy problem of the reverse space-time nonlocal Hirota equation with step-like initial data: q(z, 0) = o(1) as z →-∞ and q(z, 0) = δ + o(1) as z → ∞, where δ is an arbitrary positive constant. We show that the solution of the Cauchy problem can be determined by the solution of the corresponding matrix RH problem established on the plane of complex spectral parameter λ. As an example, we construct an exact solution of the reverse space-time nonlocal Hirota equation in a special case via this RH problem.

关键词： nonlocal Hirota equation Cauchy problem Riemann-Hilbert problem step-like initial data

Structural designs and mechanism insights into electrocatalytic oxidation of 5-hydroxymethylfurfural

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Journal of Energy Chemistry 2025年第1期100卷 792-814页

作者： Jing Lei huijie Zhang Jian Yang Jia Ran Jiqiang Ning Haiyan Wang Yong hu Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Department of ChemistryZhejiang Normal UniversityJinhua 321004ZhejiangChina Jinhua Advanced Research Institute Jinhua 321019ZhejiangChina Department of Optical Science and Engineering Fudan UniversityShanghai 200438China College of Chemistry and Materials Engineering Zhejiang A&F UniversityHangzhou 311300ZhejiangChina

Biomass conversion offers an efficient approach to alleviate the energy and environmental *** oxidation of 5-hydroxymethylfurfural(HMF)has attracted tremendous attention in the latest few years for the mild synthesis conditions and high conversion efficiency to obtain 2,5-furan dicarboxylic acid(FDCA),but there still remain problems such as limited yield,short cycle life,and ambiguous reaction *** many reviews highlighting a variety of electrocatalysts for electrochemical oxidation of HMF,a detailed discussion of the structural modulation of catalyst and the underlying catalytic mechanism is still *** herein provide a comprehensive summary of the recent development of electrochemical oxidation of HMF to FDCA,particularly focusing on the mechanism studies as well as the advanced strategies developed to regulate the structure and optimize the performance of the electrocatalysts,including heterointerface construction,defect engineering,single-atom engineering,and in situ *** characterization techniques and theoretical calculation methods for mechanism and active site studies are elaborated,and challenges and future directions of electrochemical oxidation of HMF are also *** review will provide guidance for designing advanced catalysts and deepening the understanding of the reaction mechanism beneath electrochemical oxidation of HMF to FDCA.

关键词： Electrochemical oxidation of 5- hydroxymethylfurfural 2,5-Furan dicarboxylic acid Structural design Mechanism Electrocatalysts

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Electrochemical conversion of methane to bridge the gap in the artificial carbon cycle

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Journal of Energy Chemistry 2025年第1期100卷 286-308页

作者： Yuhao Peng Yuefeng Song Ihar Razanau Juanxiu Xiao Wei Xiao Di hu Guoxiong Wang College of Chemistry and Molecular Sciences Hubei Key Laboratory of Electrochemical Power SourcesWuhan UniversityWuhan 430072HubeiChina State Key Laboratory of Catalysis Dalian National Laboratory for Clean EnergyiChEM(Collaborative Innovation Center of Chemistry for Energy Materials)Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina Laboratory of Physical-Chemical Technologies SSPA Scientific and Practical Materials Research Centre of NAS of BelarusMinsk 220072Belarus State Key Laboratory of Marine Resources Utilization in South China Sea Collaborative Innovation Center of Marine Science and TechnologySchool of Marine Science and EngineeringHainan UniversityHaikou 570228HainanChina Department of Chemical and Environmental Engineering University of Nottingham Ningbo ChinaNingbo 315100ZhejiangChina

Methane, an abundant one-carbon(C_(1)) resource, is extensively used in the industrial production of vital fuels and value-added chemicals. However, current industrial methane conversion technologies are energy-and carbon-intensive, mainly due to the high activation energy required to break the inert C–H bond, low selectivity, and problematic side reactions, including CO_(2)emissions and coke deposition. Electrochemical conversion of methane(ECM) using intermittent renewable energy offers an attractive solution, due to its modular reactor design and operational flexibility across a broad spectrum of temperatures and pressures. This review emphasizes conversion pathways of methane in various reaction systems, highlighting the significance and advantages of ECM in facilitating a sustainable artificial carbon cycle. This work provides a comprehensive overview of conventional methane activation mechanisms and delineates the complete pathways of methane conversion in electrolysis contexts. Based on surface/interface chemistry, this work systematically analyzes proposed reaction pathways and corresponding strategies to enhance ECM efficiency towards various target products, including syngas, hydrocarbons, oxygenates, and advanced carbon materials. The discussion also encompasses opportunities and challenges for the ECM process, including insights into ECM pathways, rational electrocatalyst design, establishment of benchmarking protocols, electrolyte engineering, enhancement of CH4conversion rates, and minimization of CO_(2)emission.

关键词： Methane Electrochemical conversion Reaction mechanism Catalyst design Electrode Electrocatalysis

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Effect of Parameter Variation in the BMJ Scheme on the Simulation of MJO Propagation and Structure

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Advances in Atmospheric Sciences 2025年第2期42卷 397-409页

作者： Xiaoyu Zhu Zhong ZHONG Yimin Zhu Yunying LI Yijia hu Yao HA College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410073China Key Laboratory for Virtual Geographic Environment School of Geography ScienceNanjing Normal UniversityNanjing 210023China Jiangsu Collaborative Innovation Center for Climate Change School of Atmospheric SciencesNanjing UniversityNanjing 210023China

In this study,the Betts-Miller-Janjic(BMJ)convective adjustment scheme in the Weather Research and Forecasting(WRF)model version 4.0 was used to investigate the effect of itsα-parameter,which influences the first-guess potential temperature reference profile on the Madden-Julian oscillation(MJO)propagation and *** study diagnosed the MJO active phase composites of the MJO-filtered outgoing longwave radiation(OLR)during the December-to-February(DJF)period of 2006-2016 over the Indian Ocean(IO),Maritime Continent(MC),and western Pacific(WP).The results show that the MJO-filtered OLR intensity,propagation pattern,and MJO classification(standing,jumping,and propagating clusters)are sensitive to theα-value,but the phase speeds of propagating MJOs are ***,with an increasingα-value,the simulated MJO-filtered OLR intensity increases,and the simulated propagation pattern is *** also show that the intensity and propagation pattern of an eastward-propagating MJO are associated with MJO circulation structures and thermodynamic ***αincreases,the front Walker cell and the low-level easterly anomaly are enhanced,which premoistens the lower troposphere and triggers more active shallow and congestus *** enhanced shallow and congestus convection preconditions the lower to middle troposphere,accelerating the transition from congestus to deep convection,thereby facilitating eastward propagation of the ***,the simulated MJO tends to transfer from standing to eastward propagating asα*** summary,increasing theα-value is a possible way to improve the simulation of the structure and propagation of the MJO.

关键词： MJO WRF model BMJ scheme low-level easterly anomaly

Constrained Networked Predictive Control for Nonlinear Systems Using a High-Order Fully Actuated System Approach

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IEEE/CAA Journal of Automatica Sinica 2025年第2期12卷 478-480页

作者： Yi huang Guo-Ping Liu Yi Yu Wenshan hu the School of Electrical Engineering and Automation Wuhan University IEEE the Center for Control Science and Technology Southern University of Science and Technology the Department of Electrical and Electronic Engineering The Hong Kong Polytechnic University

Dear Editor,In this letter, a constrained networked predictive control strategy is proposed for the optimal control problem of complex nonlinear highorder fully actuated (HOFA) systems with noises. The method can effectively deal with nonlinearities, constraints, and noises in the system, optimize the performance metric, and present an upper bound on the stable output of the system.

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A Novel Model for Describing Rail Weld Irregularities and Predicting Wheel-Rail Forces Using a Machine Learning Approach

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 555-577页

作者： Linlin Sun Zihui Wang Shukun Cui Ziquan Yan Weiping hu Qingchun Meng State Key Laboratory of High-Speed Railway Track System China Academy of Railway Sciences Corporation LimitedBeijing100081China Railway Engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing100081China School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China

Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed *** can cause significant wheel-rail dynamic interactions,leading to wheel-rail noise,component damage,and *** researchers have employed the vehicle-track interaction dynamic model to study the dynamic interactions between wheel and rail induced by rail weld geometry ***,the cosine wave model used to simulate rail weld irregularities mainly focuses on the maximum value and neglects the geometric *** this study,novel theoretical models were developed for three categories of rail weld irregularities,based on measurements of the high-speed railway from Beijing to *** vertical dynamic forces in the time and frequency domains were compared under different running *** forces generated by the rail weld irregularities that were measured and modeled,respectively,were compared to validate the accuracy of the proposed ***,based on the numerical study,the impact force due to rail weld irrregularity is modeled using an Artificial Neural Network(ANN),and the optimum combination of parameters for this model is *** results showed that the proposed model provided a more accurate wheel/rail dynamic evaluation caused by rail weld irregularities than that established in the *** ANN model used in this paper can effectively predict the impact force due to rail weld irrregularity while reducing the computation time.

关键词： Rail weld irregularity high-speed railway vehicle-track coupled dynamics wheel/rail dynamic vertical force artificial neural networks

Biisoindolylidene solvatochromic fluorophores: Synthesis and photophysical properties

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Chinese Chemical Letters 2025年第2期36卷 394-399页

作者： Xiaoyu Chen Jiahao hu Jingyi Lin Haiyang huang Changqing Ye Hongli Bao College of Chemistry Fuzhou University State Key Laboratory of Structural Chemistry Key Laboratory of Coal to Ethylene Glycol and Its Related TechnologyCenter for Excellence in Molecular SynthesisFujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fujian College University of Chinese Academy of SciencesFuzhou 350002China dUniversity of Chinese Academy of Sciences

Environment-sensitive fluorescent probes are commonly utilized in various fields, including fluorescence sensing and imaging. This paper describes the synthesis and photophysical properties of a novel class of solvatochromic fluorophores that incorporate biisoindolylidene as the core backbone. This study investigates the structure-property relationships of these newly developed fluorophores. The central biisoindolylidene acts as an efficient electron acceptor, and by modifying the aryl ring substituent at the 3,3 position, the photophysical properties of the fluorophores can be significantly enhanced, particularly in terms of photoluminescence quantum efficiency. Furthermore, when an electron-donor group replaces the aryl ring at the 3,3 position, intriguing solvatochromic behavior is observed. This leads to a red-shift in the maximum emission wavelength and an increase in the Stokes shift with increasing solvent polarity. In solvent dimethyl sulfoxide(DMSO), the maximum emission wavelength can reach up to 750 nm,with a Stokes shift of approximately 150 nm. Finally, the potential application of the fluorophore in the detection of volatile acids is explored in a preliminary manner.

关键词： Acid sensitive Biisoindolylidene Electron receptor New fluorophores Solvatochromic

A color-changing carbon dots/hydrogel composite for human motion sensing and sweat pH detection

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Nano Research 2025年第2期18卷 1-10页

作者： Junje Cai huajiang hu Jiurong Li Junfei Liao Xiao Gong State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China

Carbon dots(CDs)are a type of fluorescent nanomaterial that have gained significant attention due to their simple synthesis method and excellent optical *** unique structure of CDs also allows for effective luminescence *** have been reported to be pH-sensitive in many ***,most of these reports are based on the variation of the luminescence intensity of CDs with pH *** are few reports on exploring the linearly tunable variation of the luminescence wavelength with pH ***,we synthesized novel pH-sensitive CDs using a simple solvothermal *** synthesized CDs can change their luminescence emission wavelength by simply adjusting the pH of the *** change in emission wavelength may be due to the alteration in the surface state of the CDs caused by the pH *** luminous color change of the CDs allows for visual detection of the pH of the *** addition,a color-changing hydrogel composite for pH sensing was designed based on the pH sensitivity of the *** CDs@hydrogel has conductive properties that enable it to be used for motion sensing and sweat pH detection.

关键词： carbon dots multicolor pH-sensitive hydrogel motion sensing

Full biosynthetic pathway of pyrrolobenzoxazines

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Chinese Chemical Letters 2025年第1期36卷 433-436页

作者： Kunya Wang Bingyu Liu Daojiang Yan Jian Bai Haibo Yu Youcai hu State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China

Pyrrolobenzoxazines are a rare terpene-amino acid family of natural products with potent biological ***,we reported the full biosynthetic pathway of paeciloxazine(1),a typical pyrrolobenzoxazine,with significant insecticidal *** on heterologous expression,chemical complement experiment,and in vitro biochemical assays,we demonstrated the sesquiterpene portion of 1 derived from discontinuously oxidations of amorphdiene,in which P450 monooxygenase PaxH catalyzed a cascade of hydroxylation and epoxidation,while two flavin dependent monooxygenases are involved in the transformation of the esterified tryptophan into a pyrrolobenzoxazine ***,a total of 15 compounds were generated through heterologous expression,of which 13,17 and 20 showed potential antiepileptic *** study fully elucidated the biosynthetic pathway of paeciloxazine(1)and showed the diversity and complexity of constructing natural products by organisms.

关键词： Pyrrolobenzoxazines Paeciloxazine Biosynthesis P450 monooxygenase Antiepileptic activity

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