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NHC-mediated photocatalytic para-selective C–H acylation of aryl alcohols: regioselectivity control via remote radical spiro cyclization

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Science China Chemistry 2025年

作者： Tinglei Zhang Lala Wang Xiaolin Peng Tianhui Liao Dongmei Chen Ting Tu Donghan Liu Ziye Cheng Shiqing Huang Shi-chao ren Xinglong Zhang Yonggui Robin Chi State Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide and Agricultural Bioengineering Ministry of Education Guizhou University Qiannan Medical College for Nationalities School of Chemistry Chemical Engineering and Biotechnology Nanyang Technological University Department of Chemistry The Chinese University of Hong Kong Institute of High Performance Computing Agency for Science Technology and Research

Friedel-Crafts reaction and transition-metal catalysis represent primary methodologies for arene acylation; however, suffer from certain limitations, such as electronic effect-dependent reactivity, regioselectivity issues, the necessity of directing group, and relatively exceptionally limited exploration in meta-and para-acylations. N-heterocyclic carbene(NHC) catalysis has recently emerged as a promising alternative strategy for arene acylation, offering distinct regioselectivity profiles that are challenging to achieve through known methods. Herein, an NHC-mediated photo-catalytic para-selective C–H acylation of aryl alcohols is disclosed. The reaction employs a remote radical-induced temporary spiro cyclization strategy, proceeding via tandem radical dearomatization, radical acylation, rearomatization processes. Combined experimental and computational mechanistic studies support the proposed reaction pathway and observe an exclusive para-selectivity regardless of the nature of the substituents on the substrates. Despite the less satisfactory yields, the current method exhibits non-electronic nature-based reactivity and regioselectivity, enabling quick access to acylated arenes that are difficult or impossible for reported methods.

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Chiral boryl radical catalyzed asymmetric radical cycloisomerization

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Science China Chemistry 2024年第7期67卷 2121-2123页

作者： Jiamiao Jin Shi-chao ren Yonggui Robin Chi National Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide and Agricultural BioengineeringMinistry of EducationGuizhou UniversityGuiyang 550025China School of Chemistry Chemical Engineeringand BiotechnologyNanyang Technological UniversitySingapore 637371Singapore

Asymmetric catalytic organic synthesis is of profound importance in modern research and industries,providing optically enriched molecules with diverse structures and functions[1].Enzymes,transition metal complexes,and simple organic molecules have all been found as powerful catalysts that enable the bond breaking and forming events with excellent control over stereo-selectivity *** the realm of designed small molecule organic catalysts.

关键词： radical catalyzed asymmetric

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A Super-resolution Perception-based Incremental Learning Approach for Power System Voltage Stability Assessment with Incomplete PMU Measurements

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CSEE Journal of Power and Energy Systems 2022年第1期8卷 76-85页

作者： chao ren Yan Xu Junhua Zhao Rui Zhang Tong Wan Interdisciplinary Graduate School Nanyang Technological UniversitySingapore School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore School of Science and Engineering The Chinese University of Hong Kong(Shenzhen)China Changsha University of Science and Technology Changsha 410114China School of Electrical and Information Engineering University of SydneySydneyAustralia

This paper develops a fully data-driven,missingdata tolerant method for post-fault short-term voltage stability(STVS)assessment of power systems against the incomplete PMU *** super-resolution perception(SRP),based on a deep residual learning convolutional neural network,is employed to cope with the missing PMU *** incremental broad learning(BL)is used to rapidly update the model to maintain and enhance the online application *** different from the state-of-the-art methods,the proposed method is fully data-driven and can fill up missing data under any PMU placement information loss and network topology change *** results demonstrate that the proposed method has the best performance in terms of STVS assessment accuracy and missing-data tolerance among the existing methods on the benchmark testing system.

关键词： Data-driven deep residual convolutional neural network incremental broad learning short-term voltage stability super-resolution perception

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Post-disturbance transient stability assessment of power systems towards optimal accuracy-speed tradeoff

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Protection and Control of Modern Power Systems 2018年第1期3卷 203-212页

作者： chao ren Yan Xu Yuchen Zhang Interdisciplinary Graduate School Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore School of Electrical and Electronic Engineering Nanyang Technological UniversitySingaporeSingapore School of Electrical Engineering and Telecommunication University of New South WalesSydneyAustralia

The recent development of phasor measurement technique opens the way for real-time post-disturbance transient stability assessment(TSA).Following a disturbance,since the transient instability can occur very fast,there is an urgent need for fast TSA with sufficient *** paper first identifies the tradeoff relationship between the accuracy and speed in post-disturbance TSA,and then proposes an optimal self-adaptive TSA method to optimally balance such *** uses ensemble learning and credible decision-making rule to progressively predict the post-disturbance transient stability status,and models a multi-objective optimization problem to search for the optimal balance between TSA accuracy and *** such optimally balanced TSA performance,the TSA decision can be made as fast as possible while maintaining an acceptable level of *** proposed method is tested on New England 10-machine 39-bus system,and the simulation results verify its high efficacy.

关键词： Ensemble learning Extreme learning machine(ELM) Intelligent system(IS) Multi-objective optimization Transient stability assessment

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Understanding Discrepancy of Power System Dynamic Security Assessment with Unknown Faults: A Reliable Transfer Learning-based Method

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 427-431页

作者： chao ren Han Yu Yan Xu Zhao Yang Dong School of Computer Science and Engineering Nanyang Technological UniversitySingapore School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore

This letter proposes a reliable transfer learning(RTL)method for pre-fault dynamic security assessment(DSA)in power systems to improve DSA performance in the presence of potentially related unknown *** takes individual discrepancies into consideration and can handle unknown faults with incomplete *** experiment results demonstrate high DSA accuracy and computational efficiency of the proposed RTL *** analysis shows RTL can guarantee system performance.

关键词： Adversarial training dynamic security assessment maximum classifier discrepancy missing data transfer learning

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Comparison of clinical laboratory tests between bacterial sepsis and SARS-CoV-2-associated viral sepsis

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Military Medical Research 2021年第2期8卷 278-280页

作者： chao ren ren-Qi Yao Di ren Ying Li Yong-Wen Feng Yong-Ming Yao Department of Critical Care Medicine the Second People’s Hospital of ShenzhenShenzhen 518035GuangdongChina Department of Critical Care Medicine the Third People’s Hospital of ShenzhenShenzhen 518020GuangdongChina Trauma Research Center the Fourth Medical Center and Medical Innovation Research Department of the Chinese PLA General HospitalBeijing 100048China

Sepsis is a life-threatening condition that is characterized by multiple organ dysfunction due to abnormal host response to various pathogens,like bacteria,fungi and *** differences between viral and bacterial sepsis are indeed of great significance to deepen the understanding of the pathogenesis of sepsis,especially under pandemics of SARS-CoV-2 infection.

关键词： Severe acute respiratory syndrom coronavirus 2 Coronavirus disease 2019 Sepsis Bacteria Virus Infection Host response

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Jointly optimized congestion control, forwarding strategy,and link scheduling in a named-data multihop wireless network

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Frontiers of Information Technology & Electronic Engineering 2017年第10期18卷 1573-1590页

作者： Cheng-cheng LI ren-chao XIE Tao HUANG Yun-jie LIU State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing Advanced Innovation Center for Future Internet Technology Beijing University of Technology

As a promising future network architecture, named data networking(NDN) has been widely considered as a very appropriate network protocol for the multihop wireless network(MWN). In named-data MWNs, congestion control is a critical issue. Independent optimization for congestion control may cause severe performance degradation if it can not cooperate well with protocols in other layers. Cross-layer congestion control is a potential method to enhance performance. There have been many cross-layer congestion control mechanisms for MWN with Internet Protocol(IP). However, these cross-layer mechanisms for MWNs with IP are not applicable to named-data MWNs because the communication characteristics of NDN are different from those of IP. In this paper, we study the joint congestion control, forwarding strategy, and link scheduling problem for named-data MWNs. The problem is modeled as a network utility maximization(NUM) problem. Based on the approximate subgradient algorithm, we propose an algorithm called ‘jointly optimized congestion control, forwarding strategy, and link scheduling(JOCFS)'to solve the NUM problem distributively and iteratively. To the best of our knowledge, our proposal is the first cross-layer congestion control mechanism for named-data MWNs. By comparison with the existing congestion control mechanism, JOCFS can achieve a better performance in terms of network throughput, fairness, and the pending interest table(PIT) size.

关键词： Information-centric networking Congestion control Cross-layer design Multihop wireless network

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Height and Attitude Control for Small Unmanned Helicopter with Uncertainties and Disturbances 36

Height and Attitude Control for Small Unmanned Helicopter wi...

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第36届中国控制会议

作者： chao ren chaoyang Dong Qing Wang School of Aeronautic Science and Engineering Beihang University School of Automation Science and Electrical Engineering Beihang University

ISBN: (纸本)9781538629185

In this paper, a command filter-based backstepping controller is proposed for robust height and attitude tracking for small unmanned helicopter with flapping dynamics. Firstly, the helicopter model is divided into height subsystem and attitude subsystem, which are presented in strict feedback form. Then a second-order command filter is applied to obtain the derivative of virtual control laws and introduce amplitude and rate limits into control signals, thus the explosion of differentiation terms problem during backstepping process is solved, and actuators saturation is avoided. Meanwhile, the extended state observer（ESO） is designed to estimate and compensate the total uncertainty, which includes parametric uncertainties and external disturbances. Furthermore, globally bounded stability of the closed-loop helicopter system is proved by using Lyapunov ***, simulation results illustrate the applicability of the proposed controller in the presence of uncertain terms in the model.

关键词： Unmanned helicopter Backstepping Command filter Extended state observer Flapping dynamics

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Diagenetic mineralogy and its effect on the reservoir properties of the sandstones of the Permian of S120 block(Sulige gas field),Ordos Basin,NW China

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Journal of Palaeogeography 2022年第3期11卷 360-386页

作者： Qi Wan Ai-Ping Fan ren-chao Yang Nils Lenhardt Shandong Provincial Key Laboratory of Depositional Mineralization&Sedimentary Minerals Shandong University of Science and TechnologyQingdao266590China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao266071China Department of Geology University of PretoriaPrivate Bag X200028PretoriaSouth Africa

The characteristics of diagenetic minerals and their effects on reservoir quality of the tight sandstones of the Permian in Sulige gas field of the Ordos Basin were studied through observations on thin sections,scanning electron microscopy,energy dispersive spectroscopy analysis and electron microprobe *** minerals in the Permian sandstones consist of illite,kaolinite,chlorite,siliceous and calcite *** amounts of intercrystalline pores between kaolinite and illite provide channels for acidic fluids flow and thereby were conducive to the formation of clastic solution pores,intergranular solution pores and composite *** chlorite occurs in the form of three morphotypes as grain-coating,pore-lining and ***-coating and pore-lining chlorite with different crystal shapes occur as coatings on the framework ***-filling chlorite precipitated as discrete flaky plates in pore *** microcrystals developed but quartz overgrowth did not develop because of the occurrence of porelining ***,in turn,led to the preservation of primary pores by occupying potential nucleation sites for quartz overgrowth and thereby preventing quartz microcrystals from merging into quartz *** process is regarded as the most important for influencing the quality of the lithophysical *** cement was mainly precipitated during a late diagenetic stage and has a negative effect on the reservoir *** study provides important insights into analyzing the relationship between diagenetic minerals and reservoir quality and the results are directly applicable to the exploration and development of tight sandstone reservoirs all over the world.

关键词： Ordos basin Sulige gas field Permian Diagenetic processes Siliceous cement Chlorite

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Wireless semantic communication based on semantic matching multiple access and intent bias multiplexing

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The Journal of China Universities of Posts and Telecommunications 2024年第1期31卷 26-36页

作者： ren chao He Zongrui Sun Chen Li Haojin Zhang Haijun University of Science and Technology Beijing Beijing 100083China Research and Development Center Sony(China)LimitedBeijing 100027China

This paper proposes a multi-access and multi-user semantic communication scheme based on semantic matching and intent deviation to address the increasing demand for wireless users and *** scheme enables flexible management of long frames,allowing each unit of bandwidth to support a higher number of *** leveraging semantic classification,different users can independently access the network through the transmission of long concatenated sequences without modifying the existing wireless communication *** overcome the potential disadvantage of incomplete semantic database matching leading to semantic intent misunderstanding,the scheme proposes using intent deviation as an *** allows different receivers to interpret the same semantic information differently,enabling multiplexing where one piece of information can serve multiple users with distinct *** results show that at a bit error rate(BER)of 0.1,it is possible to reduce the transmission by approximately 20 semantic basic units.

关键词： semantic communication multiple access multiplexing multimodal communication

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