检索结果-南通市图书馆

Chemical Research in Chinese Universities 2024年第4期40卷 682-689页

作者： ma Shaohua TANG Zhiyong CAS Key Laboratory for Nanosystem and Hierarchical fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190P.R.China University of Chinese Academy of Sciences Beijing100049P.R.China

The construction of heterogeneous frustrated Lewis pairs(fLPs)catalysts is crucial for realizing highly efficient and recyclable pyridines catalytic *** this work,we prepared a recyclable heterogenous fLPs catalyst CMP-Bf with conjugated microporous polymer CMP-ethynyl as the support via self-catalyzed 1,1-carboboration reaction with commercial Lewis acid B(C_(6)f_(5))_(3).The as-synthesized CMP-Bf demonstrates superior heterogenous catalytic hydrogenation performance(conversion>99%),and considerable stability(84%conversion after three cycles)in recyclable hydrogenation of 2,*** work provides insights into the fabrication and catalytic application of recyclable heterogenous fLP catalysts.

关键词： Pyridine hydrogenation frustrated Lewis pair Conjugated microporous polymer

Bioinspired nanomaterials for the treatment of bacterial infections

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第2期17卷 691-714页

作者： Xiaojing ma Wenjing Tang Rong Yang Robert f.Smith School of Chemical&Biomolecular Engineering Cornell UniversityIthacaNY 14853USA

Infectious diseases pose a serious threat to global *** immunizations can control most viral infections,bacterial infections,particularly those caused by drug-resistant strains,continue to cause high rates of illness and ***,the creation of new antibiotics has come to a grinding halt in the last ten *** response to this crisis,nanotechnology has emerged as a hopeful solution to tackle drug resistance and enhance treatment results.A large variety of biomimetic nanomaterials,termed nanozymes,have demonstrated strong antimicrobial *** the inherent toxicity of nanomaterials is a concern,recent studies have harnessed the stimuli-responsiveness of nanomaterials to enable local and/or targeted delivery to reduce the treatment side ***,the physicochemical versatility of nanomaterials affords many degrees of freedom that enable rational design of smart or autonomous therapeutics,which cannot be achieved using conventional *** design straddles the fields of catalysis,nanoscience,microbiology,and translational *** provide an overview of this interdisciplinary landscape,this review is organized based on composition into lipid,metal,metal oxide,and non-metallic *** as a delivery vehicle enhance bioavailability and reduce ***-and metal oxide-based nanomaterials inhibit bacterial growth by mimicking natural enzymatic activities such as peroxidase(POD)and ***,carbon-,polymer-,and cell membrane-based nanomaterials are combined into a discussion on non-metallic *** the end of this review,potentially fruitful directions for future bioinspired nanomaterials in infectious disease treatment are included.

关键词： bioinspired nanomaterial bacteria infectious disease antimicrobial liposome nanozyme

Partial regularity and nonlinear potential estimates for Stokes systems with super-quadratic growth

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China mathematics 2024年第7期67卷 1525-1554页

作者： Lingwei ma Zhenqiu Zhang School of mathematical Sciences Tianjin Normal UniversityTianjin300387China School of mathematical Sciences and LPMC Nankai UniversityTianjin300071China

This paper builds a bridge between partial regularity theory and nonlinear potential theory for the following generalized stationary Stokes system with super-quadratic growth and continuous coefficients:-div A(x,Du)+■π=f,div u=0,where Du is the symmetric part of the gradient■*** first establish anε-regularity criterion involving both the excess functional of the symmetric gradient Du and Wolff potentials of the nonhomogeneous term f to guarantee the local vanishing mean oscillation(VMO)-regularity of Du in an open subset Ω_(u) of Ω with full *** anε-regularity criterion leads to a pointwise Wolff potential estimate of Du,which immediately infers that Du is partially C^(0)-regular under appropriate ***,we give a local continuous modulus estimate of Du.

关键词： nonlinear Stokes system partial regularity Wolff potential estimates continuous modulus estimates

Lifetime-tunable circularly polarized luminescent system based on triplet-to-singlet förster resonance energy transfer

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第9期67卷 2918-2922页

作者： Zhenyi He Zizhao Huang Xiang ma Key Laboratory for Advanced materials and feringa Nobel Prize Scientist Joint Research Center Institute of Fine ChemicalsSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Circularly polarized luminescence(CPL)materials have received widespread attention due to their remarkable performance and broad ***,current CPL material research primarily focuses on tunable color,intensity,and *** CPL with adjustable lifetime remains a significant ***,a series of CPL polymeric materials with tunable lifetime were obtained by employing phosphorescent terephthalic acid and chiral organic small molecule R/S-BNAf(a luminescent binaphthol derivative)to copolymerize with acrylamide in different *** was verified that this performance results from the different energy transfer efficiency between luminophores with varying ratios of the monomers for *** strategy to realize CPL with tunable lifetime by modulating the energy transfer efficiency will provide a new perspective to broaden the applications of CPL materials.

关键词： circularly polarized luminescence tunable lifetime förster resonance energy transfer room temperature phosphorescence

Self-attention Guidance Based Crowd Localization and Counting

在线全文

学校读者我要写书评

暂无评论

machine Intelligence Research 2024年第5期21卷 966-982页

作者： Zhouzhou ma Guanghua Gu Wenrui Zhao School of Information Science and Engineering Yanshan UniversityQinhuangdao066000China Hebei Key Laboratory of Information Transmission and Signal Processing Qinhuangdao066000China

Most existing studies on crowd analysis are limited to the level of counting,which cannot provide the exact location of *** paper proposes a self-attention guidance based crowd localization and counting network(SA-CLCN),which can simultaneously locate and count *** take the form of object detection,using the original point annotations of crowd datasets as supervision to train the ***,the center point coordinate of each head as well as the number of crowds are ***,to cope with the spatial and positional variations of the crowd,the proposed method introduces transformer to construct a globallocal feature extractor(GLfE)together with the convolutional *** establishes the near-to-far dependency between elements so that the global context and local detail features of the crowd image can be extracted ***,this paper designs a pyramid feature fusion module(PffM)to fuse the global and local information from high level to low level to obtain a multiscale feature *** downstream tasks,this paper predicts candidate point offsets and confidence scores by a simple regression header and classification *** addition,the Hungarian algorithm is used to match the predicted point set and the labelled point set to facilitate the calculation of *** proposed network avoids the errors or higher costs associated with using traditional density maps or bounding box ***,we have conducted extensive experiments on several crowd datasets,and the proposed method has produced competitive results in both counting and localization.

关键词： Crowd localization crowd counting transformer point supervision object detection

Genetic characteristics of H1N1 influenza virus outbreak in China in early 2023

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Virologica Sinica 2024年第3期39卷 520-523页

作者： Xuanxuan Li Zefeng Dong Jiaming Li Chuanran Dou Deyu Tian Zhenghai ma Wenjun Liu George f.Gao Yuhai Bi College of Life Science and Technology Xinjiang UniversityUrumchi830046China CAS Key Laboratory of Pathogen Microbiology and Immunology Institute of MicrobiologyCenter for Influenza Research and Early-warning(CASCIRE)CAS-TWAS Center of Excellence for Emerging Infectious Diseases(CEEID)Chinese Academy of SciencesBeijing100101China Suzhou Center for Disease Control and Prevention Suzhou215004China Lafayette College EastonPA 18042USA University of Chinese Academy of Sciences Beijing100049China D.H.Chen School of Universal Health Zhejiang UniversityHangzhou 310058China

Dear Editor,Influenza A virus(IAV)exhibits rapid mutability and antigenic *** the 20th century,IAV has caused at least four pandemics(Yang et al.,2022).Presently,seasonal H_(3)N_(2)and H1N1 are the prevailing human-adaptive IAV subvariants responsible for human *** implementation of public health interventions since the commencement of the COVID-19 pandemic has effectively curtailed global influenza circulation(Olsen et al.,2021).following the downregulation of the prevention and control strategies against COVID-19,global influenza activity is showing a recovery.

关键词： influenza prevention H1N1

Near-infrared non-fused electron acceptors for efficient organic photovoltaics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第4期35卷 436-441页

作者： Wenxiang ma Xinyu He Tianyi Chen De-Li ma Hongzheng Chen Chang-Zhi Li State Key Laboratory of Silicon and Advanced Semiconductor materials Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

Developing narrow-bandgap organic semiconductors is important to facilitate the advancement of organic photovoltaics(OPVs). Herein, two near-infrared non-fused ring acceptors(NIR NfRAs), PTBfTT-f and PTBfTT-Cl have been developed with A-π_A-π_D-D-π_D-π_A-A non-fused structures. It is revealed that the introduction of electron deficient π-bridge(π_A) and multiple intramolecular noncovalent interactions effectively retained the structural planarity and intramolecular charge transfer of NfRAs, extending strong NIR photon absorption up to 950 nm. further, the chlorinated acceptor, with the enlarged π-surface compared to the fluorinated counterpart, promoted not only molecular stacking in solid, but also the desirable photochemical stability in ambient, which are helpful to thereby improve the exciton and charge dynamics for the corresponding OPVs. Overall, this work provides valuable insights into the design of NIR organic semiconductors.

关键词： Organic photovoltaic Near-infrared Non-fused electron acceptor Noncovalent interaction Stability

Guest-adaptive chiral coassembly of a conformationally locked host into supramolecular boxes and ladders through arene-perfluoroarene force

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第10期67卷 3482-3492页

作者： Weilong ma Xinyi Li Aiyou Hao Pengyao Xing School of Chemistry and Chemical Engineering Shandong UniversityJinan 250100China

Unveiling the role of weak non-covalent forces in chiral self-assembly is pivotal in the design and fabrication of functional chiroptical *** nature of arene-perfluoroarene(AP)force is the electrostatic attraction betweenπ-hole andπplanes of perfluoroarenes and polyaromatic hydrocarbons(PAHs),which is emerging in constructing supramolecular motifs and coassembled optical *** this work,we reveal the potential of AP forces in building diversified levels of chiral coassemblies adaptive to the geometries of *** naphthalene-f8was covalently conjugated with a chiral amine,which folded into a semi-rectangular geometry via two intramolecular f···H *** of naphthalene,anthracene,pyrene,carbazole,perylene and benzoperylene were introduced to afford coassemblies in the crystalline state.X-ray structures suggest the formation of supramolecular boxes that encapsulate the PAHs with a 2:1 stoichiometric ratio,as well as the formation of consecutive layered ladders with a 1:1 stoichiometric *** preference is adaptive to the geometries of PAHs,and experimental and computational results evidenced the ladder structures possess strong binding *** this top,the selective chiral recognition in the mixtures of PAHs was realized,which shows promising applications in the separation of PAHs and rational design of crystalline chiroptical materials.

关键词： arene-perfluoroarene force coassembly supramolecular chirality selectivity

同方期刊数据库

Experimental investigation on weak shock wave mitigation characteristics of flexible polyurethane foam and polyurea

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第1期31卷 179-191页

作者： Shiyu Jia Cheng Wang Wenlong Xu Dong ma fangfang Qi State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Institute for Advanced Technology Shandong UniversityJinan250061China

In recent years,explosion shock wave has been considered as a signature injury of the current military *** strong shock wave is lethal to the human body,weak shock wave can cause many more lasting *** investigate the protection ability and characteristics of flexible materials and structures under weak shock wave loading,the blast wave produced by TNT explosive is loaded on the polyurethane foam with the density of 200.0 kg/m3(f-200)and 400.0 kg/m3(f-400),polyurea with the density of 1100.0 kg/m^(3)(P-1100)and structures composed of the two materials,which are intended for individual *** results indicate that the shock wave is attenuated to weak pressure disturbance after interacting with the flexible materials which are not *** shock wave protective capability of single-layer materials is dependent on their thickness,density and microscopic *** overpressure,maximum pressure rise rate and impulse of transmitted wave decrease exponentially with increase in sample *** the same thickness,f-400 provides better protective capability than f-200 while P-1100 shows the best protective capability among the three *** this study,as the materials are not destroyed,f-200 with a thickness more than10.0 mm,f-400 with a thickness more than 4.0 mm,and P-1100 with a thickness more than 1.0 mm can attenuate the overpressure amplitude more than 90.0%.further,multi-layer flexible composites are *** layer layouts of designed structures and layer thickness of the single-layer materials can affect the protective *** the research range,the structure in which polyurea is placed on the impact side shows the optimal shock wave protective performance,and the thicknesses of polyurea and polyurethane foam are 1.0 mm and 4.0 mm *** overpressure attenuation rate reached maximum value of 93.3%and impulse attenuation capacity of this structure are better than those of s

关键词： free-field explosion Weak shock wave mitigation Polyurea Polyurethane foam Multi-layered composites

Study of factors influencing the occurrence rate of 60 Hz power line radiation in the topside ionosphere:A systematic survey using the CSES satellite

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第6期67卷 1879-1892页

作者： ma ZhenHui ZHAO Shufan LIAO Li SHEN XuHui LU HengXin School of Emergency management Science and Engineering University of Chinese Academy of SciencesBeijing100049China State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing100190China Key Laboratory of Solar Activity and Space Weather National Space Science CenterChinese Academy of SciencesBeijing100190China National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing100085China Institute of Geophysics China Earthquake AdministrationBeijing100081China

We analyze the topside ionosphere power line radiation(PLR)at 60 Hz over the US using electric field data collected by CSES satellite between January 2019 and December *** study aimed to further investigate the month-to-month variation characteristic of PLR occurrence rate observed by satellite and its several influencing factors,including solar radiation,lightning activity,and try to clarify the influence of electricity *** results show that the solar radiation(solar zenith angle and f10.7)plays a major role in the variation of the PLR occurrence rate,and that there is no direct connection with the number of *** the relationship between PLR occurrence rate and electricity consumption,the low occurrence rate associated with decreased weekend electricity consumption was not observed in the ***,there is a significant difference in PLR occurrence rate between the East and West Coasts of the US at the same latitude during the same time period,suggesting that the significant difference in PLR occurrence rate is caused by the significant difference in electricity consumption between the two *** excluding the effect of solar radiation on PLR occurrence rate,we concluded that only a significant difference in regional electricity consumption could lead to a corresponding change in PLR occurrence rate detected by the Low-Earth-Orbit ***,we also found there is seasonal variation in the diurnal differences of the PLR occurrence rate caused by seasonal variation of the lower ionosphere.

关键词： CSES satellite power line radiation occurrence rate solar radiation lightning activity electricity consumption