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Effect of Low-temperature Imidization on Properties and Aggregation Structures of Polyimide Films with Different Rigidity

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Chinese Journal of Polymer Science 2024年第08期42卷 1134-1146页

作者： yan Jia Lei Zhai Song Mo Yi Liu Li-Xin Liu Xin-Yu Du Min-hui He Lin fan Key Laboratory of Science and Technology on High-tech Polymer Materials Institute of Chemistry Chinese Academy of Sciences School of Chemical Sciences University of Chinese Academy of Sciences

The traditional high-temperature preparation process of polyimide can cause many problems and limits the wider application in extreme *** important challenge to be solved urgently is the reduction of imidization *** this work,twelve kinds of polyimide films with different chain rigidity were prepared at low temperature of 200℃,in the absence or presence of imidazole used as the *** molecular rigidity and free volume were theoretically calculated,and relationship between structure and properties were systematically *** results show that imidization reaction under low temperatures is significantly affected by the rigidity of molecula r *** rigid structure of polyimide is not conducive to the low-temperature imidization,but this adverse effect can be eliminated by adding catalyst,resulting the notably increased imidization *** optical and thermal properties can be improved to a certain extent for the chemically catalyzed system,resulting in relatively higher heat resistance and thermal *** the mechanical performance could be determined by com plicating factors,greatly different from polyimide films prepa red by high temperature *** investigate aggregation structures of film s,the effect of chain rigidity and catalyst on the stacking or orientation of molecular chains was further *** wo rk can contribute to the understanding of chemically catalyzed imidization that is rarely reported in the existing research,and will provide guidance for the low-temperature preparation of high-performance polyimides.

关键词： Aggregation structures Catalyst Imidization Polyimide Structure and properties

Application of immune checkpoint inhibitors and microsatellite instability in gastric cancer

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World Journal of Gastroenterology 2024年第21期30卷 2734-2739页

作者： Shi-yan yan Jian-Gao fan Department of Gastroenterology Xinhua HospitalShanghai Jiaotong University School of MedicineShanghai 200092China

In this editorial we comment on the article by Li published in the recent issue of the World Journal of *** focus specifically on the application of immune checkpoint inhibitors(ICIs)and microsatellite instability(MSI)in gastric cancer(GC).The four pillars of GC management have long been considered,including surgery,chemotherapy,radiotherapy and targeted ***,immunotherapy has recently emerged as a“fifth pillar”,and its use is rapidly *** are four principal strategies for tumor immunotherapy:ICIs,tumor vaccines,adoptive immunotherapy and nonspecific *** them,ICIs are the most advanced and widespread type of cancer immunotherapy for *** breakthrough results for ICIs have paved the way to a new era of cancer *** particular,inhibition of the PD-1/PD-L1 axis with ICIs,including nivolumab and pembrolizumab,has emerged as a novel treatment strategy for advanced ***,these therapies are sometimes associated with often subtle,potentially fatal immune-related adverse events(irAEs),including dermatitis,diarrhea,colitis,endocrinopathy,hepatotoxicity,neuropathy and *** must be aware of these irAEs and improve the detection of these processes to prevent inappropriate discharges,emergency department revisits,and downstream *** studies have revealed that MSI-high or mismatch-repair-deficient tumors,regardless of their primary site,have a promising response to ***,it is important to detect MSI before applying ICIs for treatment of GC.

关键词： Gastric cancer Immune checkpoint inhibitors Microsatellite instability Immunotherapy Immune-related adverse events

Bioinspired designs in active metal-based batteries

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Nano Research 2024年第2期17卷 587-601页

作者： fan Zhang Ting Liao Cheng yan Ziqi Sun School of Chemistry and Physics Queensland University of TechnologyGeorge StreetBrisbaneQLD 4000Australia School of Mechanical Medical and Process Engineering Queensland University of TechnologyGeorge StreetBrisbaneQLD 4000Australia QUT Centre for Materials Science Queensland University of TechnologyGeorge StreetBrisbaneQLD 4000Australia

Active metal-based batteries are drawing increased attention because of their inherent high energy density and specific *** grand challenges,such as dendrite growth,electrode degradation,rapid performance fading,etc.,have limited their practical ***,which involves taking cues from the structures and functions of the natural world,can lead to a wealth of conceptually fresh approaches to regulator the metal ion transportation to achieve a dendrite-free metal plating,thwart the side-reaction reactions,and retard the structural distortions,for a more reliable and secure operation of active metal-based *** this review,we concentrate on the fabrication and application of bioinspired designs in active metal-based batteries with enhanced performance,along with discussion on the challenges and opportunities associated with this promising *** anticipate that this review can offer some insights into the development of functional materials by learning from nature and provide some approaches for the innovations of either the battery structures or the energy materials for metal-based batteries.

关键词： bioinspired materials energy storage devices metal-based batteries

Climatic implications in earlywood and latewood width indices of Chinese pine in north central China

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Journal of Forestry Research 2024年第3期35卷 143-153页

作者： Kaixuan yang Junzhou Zhang Haowen fan Yuan yan College of Geographic Sciences Qinghai Normal UniversityXining 810016People's Republic of China Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation(Ministry of Education) Xining 810016People's Republic of China Key Laboratory of Western China's Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730030People's Republic of China Gansu Liancheng Forest Ecosystem Field Observation and Research Station Lanzhou UniversityLanzhou 730333People's Republic of China School of Geography and Information Engineering University of GeoscienceWuhan 430074People's Republic of China

Latewood width(LWW)indices of trees are considered a reliable proxy of summer precipitation in the Northern ***,the strong coupling and high correlation between earlywood width(EWW)and LWW indices often prevent registration of climate signals of the LWW *** this study,328-year-long earlywood width and latewood width chronologies were developed from Chinese pine at two sites in the Hasi Mountains,north central *** climate responses of these chronologies were analyzed and the LWW index used to derive sum-mer precipitation *** analyses showed that LWW was particularly influenced by earlywood growth and recorded stronger climate signals of the previous year as EWW,rather than those of the current year with infrequent summer climate ***,after removing the effect of earlywood growth using a simple regression model,the adjusted LWW chronology(LWW_(adj))showed a strong relationship with July precipitation in dry *** suggests that the LWW_(adj) chronology has the potential to be used to investigate long-term variability in summer precipitation in drought-limited regions.

关键词： Dendroclimatology Latewood width Climate response Summer precipitation Earlywood effect

Synthesis of amidines via iron-catalyzed dearomative amination of β-naphthols with oxadiazolones

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Organic Chemistry Frontiers 2022年第2期9卷 380-385页

作者： yan-hui fan Xiao-Yu Guan Wen-Pei Li Cheng-Zhou Lin De-Xian Bing Mei-Zhi Sun Guo Cheng Jing Cao Jun-Jie Chen Qing-Hai Deng The Education Ministry Key Lab of Resource Chemistry Joint International Research Laboratory of Resource ChemistryMinistry of EducationShanghai Key Laboratory of Rare Earth Functional Materialsand Shanghai Frontiers Science Center of Biomimetic CatalysisCollege of Chemistry and Materials ScienceShanghai Normal UniversityShanghai 200234China

An iron-catalyzed dearomative amination of β-naphthols via a nitrene-transfer process has been ***,which have rarely been applied for the synthesis of amidines,are used as the nitrene source.A variety of amidines bearing β-naphthalenone moieties were generated smoothly in good to high yields(up to 98%)in the presence of 1.5 equivalents of tetrabutylammonium bromide,which was added as an essential additive.

关键词： catalyzed smoothly additive

Associative Tasks Computing Offloading Scheme in Internet of Medical Things with Deep Reinforcement Learning

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China Communications 2024年第4期21卷 38-52页

作者： Jiang fan Qin Junwei Liu Lei Tian hui School of Communications and Information Engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

The Internet of Medical Things(Io MT) is regarded as a critical technology for intelligent healthcare in the foreseeable 6G era. Nevertheless, due to the limited computing power capability of edge devices and task-related coupling relationships, Io MT faces unprecedented challenges. Considering the associative connections among tasks, this paper proposes a computing offloading policy for multiple-user devices(UDs) considering device-to-device(D2D) communication and a multi-access edge computing(MEC)technique under the scenario of Io MT. Specifically,to minimize the total delay and energy consumption concerning the requirement of Io MT, we first analyze and model the detailed local execution, MEC execution, D2D execution, and associated tasks offloading exchange model. Consequently, the associated tasks’ offloading scheme of multi-UDs is formulated as a mixed-integer nonconvex optimization problem. Considering the advantages of deep reinforcement learning(DRL) in processing tasks related to coupling relationships, a Double DQN based associative tasks computing offloading(DDATO) algorithm is then proposed to obtain the optimal solution, which can make the best offloading decision under the condition that tasks of UDs are associative. Furthermore, to reduce the complexity of the DDATO algorithm, the cacheaided procedure is intentionally introduced before the data training process. This avoids redundant offloading and computing procedures concerning tasks that previously have already been cached by other UDs. In addition, we use a dynamic ε-greedy strategy in the action selection section of the algorithm, thus preventing the algorithm from falling into a locally optimal solution. Simulation results demonstrate that compared with other existing methods for associative task models concerning different structures in the Io MT network, the proposed algorithm can lower the total cost more effectively and efficiently while also providing a tradeoff between delay and energy co

关键词： associative tasks cache-aided procedure double deep Q-network Internet of Medical Things(IoMT) multi-access edge computing(MEC)

Recent progresses in thermal treatment of β-Ga_(2)O_(3) single crystals and devices

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1659-1677页

作者： Yuchao yan Zhu Jin hui Zhang Deren yang State Key Laboratory of Silicon and Advanced Semiconductor Materials and School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices ZJU-Hangzhou Global Scientific and Technological Innovation CenterHangzhou 311200China

In recent years,ultra-wide bandgap β-Ga_(2)O_(3) has emerged as a fascinating semiconductor material due to its great potential in power and photoelectric *** semiconductor industrial,thermal treatment has been widely utilized as a convenient and effective approach for substrate property modulation and device ***,a thorough summary of β-Ga_(2)O_(3) substrates and devices behaviors after high-temperature treatment should be *** this review,we present the recent advances in modulating properties of β-Ga_(2)O_(3) substrates by thermal treatment,which include three major applications:(ⅰ)tuning surface electrical properties,(ⅱ)modifying surface morphology,and(ⅲ)oxidating ***,regulating electrical contacts and handling with radiation damage and ion implantation have also been discussed in device *** each category,universal annealing conditions were speculated to figure out the corresponding problems,and some unsolved questions were proposed *** review could construct a systematic thermal treatment strategy for various purposes and applications of β-Ga_(2)O_(3).

关键词： β-gallium oxide thermal treatment substrates devices

Robust Interval State Estimation for Distribution Systems Considering Pseudo-measurement Interval Prediction

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 179-188页

作者： Xu Zhang Wei yan Meiqing Huo hui Li the School of Electrical Engineering Chongqing UniversityChongqing 400044China

Interval state estimation(ISE)can estimate state intervals of power systems according to confidence intervals of predicted pseudo-measurements,thereby analyzing the impact of uncertain pseudo-measurements on ***,predicted pseudo-measurements have prediction errors,and their confidence intervals do not necessarily contain the truth values,leading to estimation biases of the *** solve this problem,this paper proposes a pseudo-measurement interval prediction framework based on the Gaussian process regression(GPR)model,thereby improving the prediction accuracy of pseudo-measurement confidence ***,a weight assignment strategy for improving the robustness of weighted least squares(WLS)ISE is *** strategy quantifies the deviation between the pseudo-measurement intervals and their estimated intervals and assigns smaller weights to the pseudo-measurement intervals with larger deviations,thereby improving the estimation accuracy and robustness of the *** paper adopts the data from the supervisory control and data acquisition(SCADA)system of the New York Independent System Operator(NYISO).It verifies the advantages of the GPR method for pseudo-measurement interval prediction by comparing it with the quantile regression and neural network *** addition,this paper demonstrates the effectiveness of the proposed weight assignment strategy through the IEEE 14-bus ***,the differences in the estimation accuracy and the bad data identification between the robust interval state estimation and deterministic state estimation are discussed.

关键词： Interval state estimation interval analysis pseudo-measurement Gaussian process regression(GPR)

Unsupervised Multi-Expert Learning Model for Underwater Image Enhancement

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 708-722页

作者： Hongmin Liu Qi Zhang Yufan Hu hui Zeng Bin fan the School of Intelligence Science and Technology and the Institute of Artificial Intelligence University of Science and Technology BeijingBeijing 100083China the School of Automation and Electrical Engineering University of Science and Technology BeijingBeijing 100083China IEEE

Underwater image enhancement aims to restore a clean appearance and thus improves the quality of underwater degraded *** methods feed the whole image directly into the model for ***,they ignored that the R,G and B channels of underwater degraded images present varied degrees of degradation,due to the selective absorption for the *** address this issue,we propose an unsupervised multi-expert learning model by considering the enhancement of each color ***,an unsupervised architecture based on generative adversarial network is employed to alleviate the need for paired underwater *** on this,we design a generator,including a multi-expert encoder,a feature fusion module and a feature fusion-guided decoder,to generate the clear underwater ***,a multi-expert discriminator is proposed to verify the authenticity of the R,G and B channels,*** addition,content perceptual loss and edge loss are introduced into the loss function to further improve the content and details of the enhanced *** experiments on public datasets demonstrate that our method achieves more pleasing results in vision *** metrics(PSNR,SSIM,UIQM and UCIQE) evaluated on our enhanced images have been improved obviously.

关键词： Multi-expert learning underwater image enhancement unsupervised learning