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

Catalytic recycling of polyesters via a binuclear catalyst

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 Chemistry 2024年第2期67卷 426-427页

作者： Bo Sun Ding ma Beijing National Laboratory for Molecular Science New Cornerstone Science LaboratoryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

Plastics play a crucial role in modern society life. While the increasing use of plastics and rapid accumulation of plastic waste in nature environment have caused severe environmental crisis and the waste of carbon resources. Catalytic upcycling is a promising approach to transform plastic waste into high value-added chemicals to achieve a sustainable circular economy.

关键词： Catalytic polyester catalyst

Nuance of inward rectifying potassium(Kir) channel dysfunctions in neurodegenerative diseases

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第6期19卷 1195-1196页

作者： Benjamin Garland Linlin ma Griffith Institute for Drug Discovery & School of Environment and Science Griffith University

Neurodegenerative disorders are highly prevalent and diverse in nature. Their manifestation largely depends on the cell types involved, with aberrant inflammatory episodes progressively inducing a constellation of phenotypes that are classified into specific diseases based on their neuropathological traits. The two most prevalent neurodegenerative diseases worldwide,

关键词： K-ATP CHANNELS PARKINSONS-DISEASE MODEL

Time-inconsistent stochastic linear-quadratic control problem with indefinite control weight costs

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China mathematics 2024年第1期67卷 211-236页

作者： Qi Lü Bowen ma School of mathematics Sichuan UniversityChengdu 610064China

A time-inconsistent linear-quadratic optimal control problem for stochastic differential equations is *** introduce conditions where the control cost weighting matrix is possibly *** such conditions,we obtain a family of closed-loop equilibrium strategies via multi-person differential *** result extends Yong’s work(2017) in the case of stochastic differential equations,where a unique closed-loop equilibrium strategy can be derived under standard conditions(namely,the control cost weighting matrix is uniformly positive definite,and the other weighting coefficients are positive semidefinite).

关键词： linear-quadratic optimal control problem time-inconsistent cost functional generalized Riccati equation indefinite control weight cost closed-loop equilibrium strategy

Extreme precipitation detection ability of four high-resolution precipitation product datasets in hilly area:a case study in Nepal

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2024年第3期15卷 390-405页

作者： Sunil Subba Yao-Ming ma Wei-Qiang ma Cun-Bo Han Land-Atmosphere Interaction and its Climatic Effects Group State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China College of Atmospheric Science Lanzhou UniversityLanzhou 730000China National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes Dingri 858200China Kathmandu Center of Research and Education Chinese Academy of SciencesBeijing 100101China China-Pakistan Joint Research Center on Earth Sciences Chinese Academy of SciencesIslamabad 45320Pakista

Given Nepal's vulnerability to extreme precipitation(EP),it is imperative to conduct a comprehensive analysis to comprehend the historical trends of such ***,acquiring precise precipitation data for EP remains challenging in mountainous countries like Nepal owing to the scarcity of densely gauged *** limitation impedes the dissemination of knowledge pertaining to EP variability events in *** current research on this topic is deficient for two main reasons:1)there is a lack of studies leveraging recently released high-resolution precipitation products to identify their EP detection capabilities,which further hinders the usability of those products in data-scarce regions like Nepal,and 2)most studies have focused on the characterisation of EP events in Nepal rather than their spatial and temporal *** address these issues,this study evaluated the EP detection capabilities of four high-resolution precipitation product datasets(PPDs)across Nepal from 1985 to *** datasets include the ERA5 Land reanalysis data,satellite-based precipitation data(PERSIANN_CCS_CDR and CHIRPS_V2.0)and a merged dataset(TPHiPr).We used various statistical and categorical indices to assess their ability to capture the spatial and temporal variability of EP *** annual EP events were characterised by 11 indices divided into frequency and intensity *** TPHiPr merged dataset offered a robust depiction of monthly precipitation estimates,achieving the highest critical success index,accuracy,probability of detection and a low false alarm ratio for daily precipitation detection of 0.1 mm in ***,the PERSIANN_CCS_CDR dataset exhibited poor *** PPDs showed increasing trends in EP ***,the TPHiPr dataset showcased those trends with fewer errors and stronger correlations for many frequency(R10mm,R20mm and R25mm)and intensity(RX1day,RX5day,PRCPTOT and R99p)*** results indicate that TPHiPr outperformed ot

关键词： Extreme precipitation Precipitation product Nepal TPHiPr ERA5 land PERSIANN_CCS_CDR CHIRPS_V2.0

Take Every Step Firmly with Sharp Eyes

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 Journal of Chemistry 2024年第10期42卷 1065-1066页

作者： Shengming ma Chinese Journal of Chemistry

Chinese Journal of Chemistry(CJC)is committed to becoming a prominent international journal for chemistry and the related *** are working very hard towards this *** offers a diverse range of manuscript types,including... 详细信息

关键词： journal becoming diverse

Impact of Polymer matrix on Polymer Mechanochromism from Excited State Intramolecular Proton Transfer

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 Journal of Chemistry 2024年第6期42卷 611-616页

作者： Yu Wu Xin Cheng Huan Hu Shui Hu Zhimin ma Zhiyong ma Beijing Advanced Innovation Center for Soft matter Science and Engineering Beijing State Key Laboratory of Organic-Inorganic CompositesCollege of Chemical EngineeringBeijing University of Chemical TechnologyBeijing100029 China Center of Advanced Elastomer materials College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing100029 China College of Engineering Peking UniversityBeijing100871 China

Mechanochromic polymers based on non-covalent changes have attracted much attention ***,we report the impact of inter/intramolecular hydrogen bonds on polymer mechanochromism from the excited state intramolecular proton transfer (ESIPT) ***-NH2-OH and PhMz=2A are designed and obtained by simple and high-yield synthesis,and are connected into polyurethane and poly(methyl acrylate-co-2-ethylhexyl acrylate),*** the initial state,the PhMz-NH2-OH@PU sample shows blue fluorescence from the excited enol form (E*) excitons,owing to intermolecular hydrogen bonds that interrupt the ESIPT reactions but the PhMz=2A@Pma-2-EA sample expresses cyan fluorescence belonging to the excited keto form (K*) emission,implying that the intramolecular hydrogen bonds ***,under stretching,external force can tune the emission of the PhMz=2A@Pma-2-EA sample from K* to E* *** external force can putatively still promote a bond rotation,ESIPT reactions remain equivalently interrupted in both the relaxed and stressed states in a hydrogen-bond donating *** calculation confirms the force-induced increase in dihedral angle for the transition of ESIPT-on/***,PhMz-NH2-OH@PU and PhMz=2A@Pma-2-EA showed disparate initial ESIPT states and further different responses/sensitivity to *** study reports a novel and efficient strategy for enriching mechanochromic investigation and extending the applications of ESIPT reactions.

关键词： Polymer mechanochromism Excited state intramolecular proton transfer Hydrogen bonding Supramolecular chemistry Elastomers

A Parameter Adaptive Method for Image Smoothing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第4期29卷 1138-1151页

作者： Suwei Wang Xiang ma Xuemei Li School of Computer Science and Technology Shandong UniversityJinan 250101China School of Software Shandong UniversityJinan 250101China

Edge is the key information in the process of image smoothing. Some edges, especially the weak edges, are difficult to maintain, which result in the local area being over-smoothed. For the protection of weak edges, we propose an image smoothing algorithm based on global sparse structure and parameter adaptation. The algorithm decomposes the image into high frequency and low frequency part based on global sparse structure. The low frequency part contains less texture information which is relatively easy to smoothen. The high frequency part is more sensitive to edge information so it is more suitable for the selection of smoothing parameters. To reduce the computational complexity and improve the effect, we propose a bicubic polynomial fitting method to fit all the sample values into a surface. Finally, we use Alternating Direction Method of Multipliers (ADMM) to unify the whole algorithm and obtain the smoothed results by iterative optimization. Compared with traditional methods and deep learning methods, as well as the application tasks of edge extraction, image abstraction, pseudo-boundary removal, and image enhancement, it shows that our algorithm can preserve the local weak edge of the image more effectively, and the visual effect of smoothed results is better.

关键词： image smoothing parameter adaptation bicubic interpolation polynomial fitting

A rigorous real-time acoustic positioning method for ocean bottom seismic exploration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Satellite Navigation 2024年第1期5卷 168-190页

作者： Jinye ma Shouchuan Fang Jianhu Zhao School of Geodesy and Geomatics Wuhan University129 Luoyu RoadWuhan430079China Institute of marine Science and Technology Wuhan UniversityWuhan430079China Surveying Service Center BGP Inc.CNPCZhuozhou072751HebeiChina

The conventional technique for positioning seafloor geophones in ocean bottom seismic exploration encounters several challenges,including the significant impact of outliers on positioning results,underutilization of high-precision observations,and low efficiency in real-time data *** issues inevitably affect the quality of seismic exploration *** address these challenges and enhance the accuracy of geophone positioning,this paper proposes a rigorous real-time acoustic positioning method for geophones based on sequential adjustment and Baarda's outlier detection *** proposed method comprises three key steps:grouping the original acoustic observations,constructing the intra-group acoustic positioning model,and synthesizing the positioning results across the different *** validity and practicality of this approach are confirmed through a simulation experiment as well as the field experiment conducted in the Bohai Sea,*** results demonstrate that the proposed method effectively eliminates outliers in the original observations and maximizes the utilization of high-quality *** to traditional acoustic positioning methods,it significantly reduces positioning errors from meters to decimeters,and in some cases can achieve centimeter-level *** the sound velocity profile in the operating sea area is measured,the method can attain the posterior standard deviation at the millimeter level and positioning errors within 10 *** the sound velocity profile is unknown,the method can achieve the posterior standard deviation at centimeter-level and positioning errors of approximately 20 cm.

关键词： Ocean bottom seismic exploration Geophone positioning Acoustic positioning method Sequential adjustment Outlier detection

Bionic soft robotic gripper with feedback control for adaptive grasping and capturing applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Mechanical Engineering 2024年第1期19卷 129-148页

作者： Tingke WU Zhuyong LIU Ziqi ma Boyang WANG Daolin ma Hexi YU Department of Engineering Mechanics School of Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China MOE Key Laboratory of Hydrodynamics Shanghai Jiao Tong UniversityShanghai 200240China

Robots are playing an increasingly important role in engineering *** robots have promising applications in several fields due to their inherent advantages of compliance,low density,and soft interactions.A soft gripper based on bio-inspiration is proposed in this *** analyze the cushioning and energy absorption mechanism of human fingertips in detail and provide insights for designing a soft gripper with a variable stiffness *** investigate the grasping modes through a large deformation modeling approach,which is verified through *** characteristics of the three grasping modes are quantified through testing and can provide guidance for robotics ***,the adaptability of the soft gripper is verified by grasping multi-scale and extremely soft ***,a cushioning model of the soft gripper is proposed,and the effectiveness of cushioning is verified by grasping extremely sharp objects and living ***,we validate the advantages of the variable stiffness of the soft gripper,and the results show that the soft robot can robustly complete assemblies with a gap of only 0.1 *** to the unstructured nature of the engineering environment,the soft gripper can be applied in complex environments based on the abovementioned experimental ***,we design the soft robotics system with feedback capture based on the inspiration of human catching *** feasibility of engineering applications is initially verified through fast capture experiments on moving *** design concept of this robot can provide new insights for bionic machinery.

关键词： soft bionic gripper variable stiffness structure large deformation modeling feedback control soft robotic system