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Recent advances of versatile reagents as controllable building blocks in organic synthesis

Chinese Chemical Letters 2024年第2期35卷 24-43页

作者： Shaomin Chen Luigi Vaccaro yanlong Gu Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China Laboratory of Green S.O.C. Dipartimento di ChimicaBiologia e BiotecnologieUniversità degli Studi di PerugiaVia Elce di Sotto 8Perugia 06123Italy School of Chemistry and Chemical Engineering The Key Laboratory for Green Processing of Chemical Engineering of Xinjiang BingtuanShihezi UniversityShihezi 832004China

Diversity-oriented synthesis is a powerful and interesting synthetic tool for the rapid construction of structurally complex and privileged scaffolds from readily accessible starting *** date,diversity-oriented synthesis mostly relies on the employment of versatile *** reagents can be regulated as controllable and flexible building blocks for multipurpose *** the past decade,a variety of multifunctional reagents have been ***,most versatile reagents usually need multi-step synthesis,thus restricting their wide application to a large *** terms of the practicalities and universalities,we prefer to pay more attention to the utilization of simple and practical versatile reagents with multiple reactivities,mainly including atropaldehyde acetals,aryl methyl ketones,vinylene carbonate,vinyl azides,aryldiazonium salts,rongalite,halodifluoromethyl *** importantly,these versatile reagents can also play different roles simultaneously in the same reaction,in which their different reactivities are converged into the final target *** strategy can not only offer more possibilities for the synthesis of several active pharmaceutical ingredients,but also minimize the occurrence of some side reactions by lessening the varieties of ***,a perspective is given at the end of this review.

关键词： Versatile reagents Divergent synthesis Dual synthons Bond cleavage Tandem reactions

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Recursive Projected Filter Algorithm with Binary-Valued Observations

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Journal of Systems Science & Complexity 2024年第5期37卷 1832-1860页

作者： ZHANG Xiaoyan WANG Ying XUE Wenchao ZHAO yanlong Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper focuses on the state estimate for a class of systems with both process noise and measurement noise under binary-valued observations,in which the Gaussian assumption on the predicted density of the state is not required.A recursive projected filter algorithm with time-varying thresholds is constructed to estimate the state under binary-valued *** time-varying thresholds are designed as the prediction value of the measurement,which can provide more information about the system *** convergence property is established with some suitable stability,boundedness and observability *** particular,the estimation error between state and estimate is proved to be asymptotically bounded in the mean-square sense,whose upper bound is related to the variance of process ***,the theoretical results are demonstrated via numerical examples of first-order and high-order systems.

关键词： Binary-valued observations convergence recursive filter time-varying thresholds

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Threshold Selection and Resource Allocation for Quantized Identification

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Journal of Systems Science & Complexity 2024年第1期37卷 204-229页

作者： WANG Ying LI Xin ZHAO yanlong ZHANG Ji-Feng Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper is concerned with the optimal threshold selection and resource allocation problems of quantized identification, whose aims are improving identification efficiency under limited resources. Firstly, the first-order asymptotically optimal quantized identification theory is extended to the weak persistent excitation condition. Secondly, the characteristics of time and space complexities are established based on the Cramér-Rao lower bound of quantized systems. On these basis, the optimal selection methods of fixed thresholds and adaptive thresholds are established under aperiodic signals, which answer how to achieve the best efficiency of quantized identification under the same time and space complexity. In addition, based on the principle of maximizing the identification efficiency under a given resource, the optimal resource allocation methods of quantized identification are given for the cases of fixed thresholds and adaptive thresholds, respectively, which show how to balance time and space complexity to realize the best identification efficiency of quantized identification.

关键词： Quantized output resource allocation system identification threshold selection.

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Numerical investigation of the photo-thermal characteristics of a direct absorption solar collector using Monte Carlo and finite volume methods

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Science China(Technological Sciences) 2024年第8期67卷 2436-2448页

作者： ZHU yanlong LI SuNing FAN JianHua KONG WeiQiang YUAN Yuan TAN HePing School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Department of Civil Engineering and Mechanical Engineering Technical University of DenmarkKoppels AlléBuilding 4042800 Kgs.LyngbyDenmark School of Vehicle and Energy Yanshan UniversityQinhuangdao 066004China

In this study, a novel model of photothermal conversion in a direct absorption solar collector based on the Monte Carlo and finite volume methods was built and validated and the temperatures of the novel and traditional solar collectors were compared. The sensitivity of the parameters to the radiative heat loss was investigated. Finally, the radiative heat transfer characteristics were discussed using the radiative exchange factor. The results of this study validated the advantages of the novel solar collector at both the surface and fluid temperatures. Under the conditions used in this study, the maximum temperature difference of the novel solar collector was 3. K, compared with 193.K for the traditional solar collector. Furthermore, the collector was divided into several units along the flow direction. The radiative exchange factor indicated that with an increase in the attenuation coefficient, the percentage of radiation intensity in the total solar radiation absorbed by the corresponding unit ***, it decreased with an increase in the incident angle and scattering albedo. These results provide a reference for addressing the low efficiency and thermal damage caused by traditional solar collectors at high temperatures.

关键词： direct absorption solar collector radiative heat transfer Monte Carlo

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Design of low-frequency circular metastructure isolators with high-load-bearing capacity

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Chinese Journal of Aeronautics 2024年第10期37卷 207-220页

作者： Ning CHEN Zhichun YANG Te YANG Yizhou SHEN Wei TIAN yanlong XU School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China National Key Laboratory of Strength and Structural Integrity Xi’an 710065China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an 710049China

Traditional vibration isolation structures cannot work effectively for low-frequency vibration under heavy loads,due to the inherent contradiction between the high-static and lowdynamic stiffness of these *** the challenge can be effectively addressed by introducing a negative stiffness mechanism,the existing structures inevitably have complex ***,a class of man-made structures with both extraordinary mechanical properties and simple configurations,provide a new insight for low-frequency vibration isolation *** this paper,circular metastructure isolators consisting of some simple beams are designed for low-frequency vibration,including a single-layer isolator and a double-layer isolator,and their static and dynamic characteristics are studied,*** the static characteristic,the force–displacement and stiffness–displacement curves are obtained by finite element simulation;for the dynamic characteristic,the vibration transmissibility curves are obtained analytically and *** result shows that the circular nonlinear single-layer isolator has excellent lowfrequency isolation performance,and the isolation frequency band will decrease about 20 Hz when the isolated mass is fixed at 1.53. kg,compared with a similar circular linear *** static and dynamic properties are well verified through *** work provides an innovative approach for the low-frequency vibration isolation and has wide potential applications in aeronautics.

关键词： Isolator Low-frequency Curved beam Metastructure Stiffness

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Prediction and driving factors of forest fire occurrence in Jilin Province,China

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Journal of Forestry Research 2024年第1期35卷 58-71页

作者： Bo Gao yanlong Shan Xiangyu Liu Sainan Yin Bo Yu Chenxi Cui Lili Cao Wildland Fire Prevention and Fighting Innovation Center of Beihua University Forestry College of Beihua University3999 Binjiang East RoadJilin City 132013People’s Republic of China

Forest fires are natural disasters that can occur suddenly and can be very damaging,burning thousands of square *** is better than suppression and prediction models of forest fire occurrence have developed from the logistic regression model,the geographical weighted logistic regression model,the Lasso regression model,the random forest model,and the support vector machine model based on historical forest fire data from 2000 to 2019 in Jilin *** models,along with a distribution map are presented in this paper to provide a theoretical basis for forest fire management in this *** studies show that the prediction accuracies of the two machine learning models are higher than those of the three generalized linear regression *** accuracies of the random forest model,the support vector machine model,geographical weighted logistic regression model,the Lasso regression model,and logistic model were 88.7%,87.7%,86.0%,85.0%and 84.6%,*** is the main factor affecting forest fires,while the impacts of topography factors,human and social-economic factors on fire occurrence were similar.

关键词： Forest fire Occurrence prediction Forest fire driving factors Generalized linear regression models Machine learning models

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Deformation Characteristics of Hydrate-Bearing Sediments

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Journal of Ocean University of China 2024年第1期23卷 149-156页

作者： DONG Lin LI yanlong ZHANG Yajuan HU Gaowei LIAO Hualin CHEN Qiang WU Nengyou Key Laboratory of Gas Hydrate Ministry of Natural ResourcesQingdao Institute of Marine GeologyQingdao 266237China Laboratory for Marine Mineral Resources Laoshan LaboratoryQingdao 266237China College of Oceanography Hohai UniversityNanjing 210098China College of Petroleum Engineering China University of Petroleum(East China)Qingdao 266555China

The safe and efficient development of natural gas hydrate requires a deep understanding of the deformation behaviors of *** this study,a series of triaxial shearing tests are carried out to investigate the deformation properties of hydrate-bearing *** of volumetric and lateral strains versus hydrate saturation are analyzed *** indicate that the sediments with high hydrate saturation show dilative behaviors,which lead to strain-softening characteristics during *** volumetric strain curves have a tendency to transform gradually from dilatation to compression with the increase in effective confining *** easy prediction model is proposed to describe the relationship between volumetric and axial *** model coefficientβis the key dominating factor for the shape of volumetric strain curves and can be determined by the hydrate saturation and stress ***,a modified model is established for the calculation of lateral *** corresponding determination method is provided for the easy estimation of model coefficients for medium sand sediments containing *** study provides a theoretical and experimental reference for deformation estimation in natural gas hydrate development.

关键词： gas hydrate deformation characteristics volumetric strain lateral strain prediction model

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Unveiling the rolling texture variations ofα-Mg phases in a dual-phase Mg-Li alloy

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Journal of Magnesium and Alloys 2024年第6期12卷 2557-2568页

作者： Xiaoyan Li Luyao Jiang Fei Guo yanlong Ma Hang Yu Qiuyu Chen Haiding Liu Dingfei Zhang College of Materials Science and Engineering Chongqing University of TechnologyChongqing 400054China Chongqing Materials Research Institute Co. Ltd.Chongqing 400707China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

LZ91 Mg-Li alloy plates with three types of initial texture were rolled by 70%reduction at both room temperature and 200℃to explore the rolling texture formation ofα-Mg *** results showed that the rolling texture is largely affected by the initial *** the samples exhibited two main texture components as RD-split double peaks texture and TD-split double peaks texture after large strain *** intensity of the two texture components was strongly influenced by the initial orientation and rolling *** twinning altered the large-split non-basal orientation to a near basal one at low rolling *** basal orientation induced by twinning is unstable,which finally transmitted to the RD-split *** strong TD-split texture formed due to slip-induced orientation transition from its initial *** competition between prismatic and basal slip determined the intensity and tilt angle of the TD-split *** increasing the rolling temperature,the TD-split texture component was enhanced in all three *** of extension twinning behavior and the promotion of prismatic slip at elevated temperature are the main reasons for the difference in hot and cold rolling texture.

关键词： Magnesium-lithium alloys Rolling texture Extension twinning Slip competition

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Recent progresses in the development of tubular segmented-in-series solid oxide fuel cells:Experimental and numerical study

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 427-442页

作者： Shuo Han Tao Wei Sijia Wang yanlong Zhu Xingtong Guo Liang He Xiongzhuang Li Qing Huang Daifen Chen School of Energy and Power Jiangsu University of Science and TechnologyZhenjiang 212003China College of Materials Science and Engineering Nanjing Forestry UniversityNanjing 210037China

Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell ***,traditional SOFCs suffer from having a higher volume,current leakage,complex connections,and difficulty in gas *** solve these problems,Rolls-Royce has fabricated a simple design by stacking cells in series on an insulating porous support,resulting in the tubular segmented-in-series solid oxide fuel cells(SIS-SOFCs),which achieved higher output *** work systematically reviews recent advances in the structures,preparation methods,perform-ances,and stability of tubular SIS-SOFCs in experimental and numerical ***,the challenges and future development of tubular SIS-SOFCs are also *** findings of this work can help guide the direction and inspire innovation of future development in this field.

关键词： solid oxide fuel cell segmented-in-series tubular experimental study numerical study

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Macro-superlubricity in sputtered MoS_(2)-based films by decreasing edge pinning effect

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Friction 2024年第1期12卷 52-63页

作者： Chunmeng DONG Dong JIANG yanlong FU Desheng WANG Qinqin WANG Lijun WENG Ming HU Xiaoming GAO Jiayi SUN State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

To date,MoS_(2) can only be achieved at *** pinning effect caused by structure defects is the most obvious barrier to expand the size of structural superlubricity to ***,we plan to pin edge planes of MoS_(2) with nanospheres,and then the incommensurate structure can be formed between adjacent rolling nanoparticles to reduce *** sputtered MoS_(2) film was prepared by the physical vapor deposition(PVD)in *** enough Cu_(2)O nanospheres(~40 nm)were generated in situ at the edge plane of MoS_(2) layers by liquid phase *** incommensurate structure(mismatch angle(θ)=8°)caused by MoS_(2) layers was formed before *** friction coefficient of the films(5 N,1,000 r/min)was~6.0×10^(−3. at the *** friction,MoS_(2) layers pinned on numerous of Cu_(2)O nanoparticles reduced its edge pinning effect and decreased ***,much more incommensurate was formed,developing macro-superlubricity.

关键词： sputtered MoS_(2)film Cu_(2)O nanospheres edge pinning effect macro-superlubricity

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