检索结果-南通市图书馆

Catalyst-free and Reprocessable Aromatic Polydithiourethanes

维普期刊数据库评论

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 Polymer Science 2024年第10期42卷 1435-1441,I0007页

作者： Bo Yang hai-Jun Feng Tian-Tian Ni xiao-Rui Zhou Tao xie Ning Zheng State Key Laboratory of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou310058China Department of Colorectal Surgery and Oncology Key Laboratory of Cancer Prevention and InterventionMinistry of EducationThe Second Affiliated HospitalZhejiang University School of MedicineHangzhou310009China

The incorporation of dynamic covalent bonds into thermosets facilitates the reprocessing of polymer networks,thereby meeting the sustainable requirements for polymer ***,the mechanical properties of many materials often decline significantly upon reprocessing due to side reactions caused by harsh processing *** this work,we find that the aromatic dithiocarbamate bond can undergo dissociation under mild conditions without the need for a catalyst,enabling the efficient reprocessing of the corresponding *** a consequence,the mechanical properties of the polydithiourethane can be largely preserved after *** discovery of this dynamic chemistry is anticipated to broaden the potential for material design in dynamic covalent polymer networks.

关键词： Reprocessing Polydithiourethane Dynamic covalent bond

A New Cytotoxic Acetogenin from the Seeds of Annona squamosa

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2003年第6期14卷 588-590页

作者： hai Hui xie, xiao Yi WEI*, Ji Dong WANG, Mei Fang LIU, Ren Zhou YANG South China Institute of Botany, Chinese Academy of Sciences, Guangzhou 510650 South China Institute of Botany Chinese Academy of Sciences Guangzhou 510650 China

A new Annonaceous acetogenin, squamostolide (1), was isolated from the seeds of Annona squamosa. Its structure was elucidated based on spectroscopic methods and comparison with known compounds. It is the first example of Annonaceous acetogenin with each of the two ends of the aliphatic chain bearing a g-lactone. The new compound exhibited cytotoxic activity in vitro against bel-7402 and CNE2 human tumor cell lines.

关键词： Annona squamosa Annona acetogenins squamostolide cytotoxicity.

Comparison of biliary protein spectrum in gallstone patients with obesity and those with normal body weight

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2024年第4期23卷 385-392页

作者： Min-Zhi Chen Ping xie xiao-Chang Wu Zhen-Hua Tan hai Qian Zhi-Hong Ma Xing Yao Department of Hepatopancreatobiliary Surgery Huzhou Central HospitalAffiliated Huzhou HospitalZhejiang University School of MedicineHuzhou 313000China Huzhou Key Laboratory of Molecular Medicine Huzhou Central HospitalAffiliated Huzhou HospitalZhejiang University School of MedicineHuzhou 313000China

Background: Obesity is a common public health issue and is currently deemed a disease. Research has shown that the risk of gallstones in individuals with obesity is elevated. This study aimed to explore the bile proteomics differences between cholelithiasis patients with obesity and normal body weight. Methods: Bile samples from 20 patients(10 with obesity and 10 with normal body weight) who underwent laparoscopic cholecystectomy at our center were subjected to tandem mass tag labeling(TMT) and liquid chromatography-tandem mass spectrometry(LC-MS/MS), followed by further bioinformatic analysis. Results: Among the differentially expressed proteins, 23 were upregulated and 67 were downregulated. Bioinformatic analysis indicated that these differentially expressed proteins were mainly involved in cell development, inflammatory responses, glycerolipid metabolic processes, and protein activation cascades. In addition, the activity of the peroxisome proliferator-activated receptor(PPAR, a subfamily of nuclear receptors) signaling pathway was decreased in the Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analysis. Two downregulated proteins in the PPAR signaling pathway, APO A-Ⅰ and APO A-Ⅱ, were confirmed using enzyme-linked immunosorbent assay. Conclusions: The PPAR signaling pathway may play a crucial role in the development of cholelithiasis among patients with obesity. Furthermore, biliary proteomics profiling of gallstones patients with obesity is revealed, providing a reference for future research.

关键词： Proteome profiling Gallstones Obesity-associated gallstones Tandem mass tag labeling PPAR signaling

Dynamic mechanical characteristics of deep Jinping marble in complex stress environments

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 630-644页

作者： Chendi Lou Heping xie Ru Zhang hai Ren Hao Luo Kun xiao Yuan Peng Qiang Tan Li Ren Institute for Disaster Management and Reconstruction Sichuan UniversityChengdu610207China College of Water Resource&Hydropower Sichuan UniversityChengdu610065China MOE Key Laboratory of Deep Earth Science&Engineering Sichuan UniversityChengdu610065China Yalong River Hydropower Development Company Ltd.Chengdu610051China (Chongqing)International Engineering Technology Company Ltd.Chongqing401121China

To reveal the dynamic mechanical characteristics of deep rocks,a series of impact tests under triaxial static stress states corresponding to depths of 300-2400 m were *** results showed that both the strain rates and the stress environments in depth significantly affect the mechanical characteristics of *** sensitivity of strain rate to the dynamic strength and deformation modulus shows a negative correlation with depth,indicating that producing penetrative cracks in deep environments is more difficult when damage *** dynamic strength shows a tendency to decrease and then increase slightly,but decreases sharply *** demonstrates a similar trend as that of strength,whereas reflectivity indicates the opposite ***,two critical depths with high dynamically induced hazard possibilities based on the China Jinping Underground Laboratory(CJPL)were proposed for deep *** first critical depth is 600-900 m,beyond which the sensitivity of rock dynamic characteristics to the strain rate and restraint of circumferential stress decrease,causing instability of surrounding rocks under axial stress *** second one lies at 1500-1800 m,where the wave impedance and dynamic strength of deep surrounding rocks drop sharply,and the dissipation energy presents a negative *** suggests that the dynamic instability of deep surrounding rocks can be divided into dynamic load dominant and dynamic load induced types,depending on the second critical depth.

关键词： Rock mechanics Split-Hopkinson pressure bar Coupled static‒dynamic loading Different depths Holmquist-Johnson-Cook(HJC)model

Holographic Polymer Nanocomposites with High Refractive Index Modulation by Doping Liquid Crystal E6M

维普期刊数据库评论

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 Polymer Science 2024年第7期42卷 926-935,I0006页

作者： Meng-Yun Wang Yue Zhang Dan Wang Ming Yao Yi-Xuan Wang Xing-Ping Zhou hai-Yan Peng xiao-Lin xie Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan430074China National Anti-counterfeit Engineering Research Center Huazhong University of Science and TechnologyWuhan430074China

Holographic optical elements(HOEs)based on polymer composites have become a research hot spot in recent years for augmented reality(AR)due to the significant improvement of optical performance,dynamic range,ease of processing and high yield ***,it remains a formidable challenge to obtain a large field of view(FOV)and brightness due to the limited refractive index ***,we report an effective method to tackle the challenge by doping an epoxy liquid crystal termed E6M,which enables a large refractive index modulation of 0.050@633 nm and low haze of 5.0%at a doping concentration of 5 wt%.This achievement may be ascribed to the improved molecular ordering of liquid crystals within the holographic polymer *** high refractive index modulation can endow transmission-type holographic polymer composites with a high diffraction efficiency of 96.2%at a small thickness of 5μm,which would promise the design of thin and lightweight AR devices.

关键词： Polymer nanocomposites Holography AR/VR Refractive index modulation Liquid crystal

Adaptive Trajectory Tracking Control for Nonholonomic Wheeled Mobile Robots:A Barrier Function Sliding Mode Approach

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1007-1021页

作者： Yunjun Zheng Jinchuan Zheng Ke Shao Han Zhao Hao xie hai Wang the School of Mechanical Engineering Hefei University of TechnologyHefei 230009China the School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyHawthorn VIC 3122Australia the School of Civil Aviation Northwestern Polytechnical UniversityXi’an 710072China the Shanghai Aerospace Control Technology Institute Shanghai 201109 the School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China the College of Science HealthEngineering and EducationMurdoch UniversityPerth WA6150Australia

The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs)is subject to nonholonomic constraints,system uncertainties,and external *** paper proposes a barrier function-based adaptive sliding mode control(BFASMC)method to provide high-precision,fast-response performance and robustness for *** with the conventional adaptive sliding mode control,the proposed control strategy can guarantee that the sliding mode variables converge to a predefined neighborhood of origin with a predefined reaching time independent of the prior knowledge of the uncertainties and disturbances *** advantage of the proposed algorithm is that the control gains can be adaptively adjusted to follow the disturbances amplitudes thanks to the barrier *** benefit is that the overestimation of control gain can be eliminated,resulting in chattering ***,a modified barrier function-like control gain is employed to prevent the input saturation problem due to the physical limit of the *** stability analysis and comparative experiments demonstrate that the proposed BFASMC can ensure the prespecified convergence performance of the NWMR system output variables and strong robustness against uncertainties/disturbances.

关键词： Adaptive sliding mode barrier function nonholonomic wheeled mobile robot(NWMR) trajectory tracking control

Kinetic Resolution of Racemic 4-Substituted Chroman-2-ones Through Asymmetric Lactone Hydrogenation

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2024年第10期6卷 2560-2576页

作者： Xiong Wu hai-Tao Yue xiao-Dong Zuo xiao-Hui Yang Pu-Cha Yan Jian-Hua xie Qi-Lin Zhou State Key Laboratory and Institute of Elemento-Organic Chemistry College of ChemistryFrontiers Science Center for New Organic MatterNankai UniversityTianjin 300071 Zhejiang Jiuzhou Pharmaceutical Co. Ltd.TaizhouZhejiang 318000

Esters are abundant in natural and synthetic products and their conversion into primary alcohols holds great importance in fine chemical ***,achieving asymmetric hydrogenation(AH)of racemic esters with remote stereocenters via kinetic resolution(KR)remains a formidable challenge due to the difficulties associated with discerning spatially distant *** address this issue,we have designed a hydroxy-assisted strategy that introduces a hydroxy group into racemicβ-aryl esters to facilitate hydrogenation and enhance chiral discrimination through a lactone *** employing chiral Ir-SpiroPAP catalysts,we achieved exceptional AH of racemic 4-substituted chroman-2-ones,lactone form of ortho-hydroxylatedβ-aryl esters,via KR,resulting in impressive selectivity factor(s)values of up to *** approach exhibited significant efficacy for racemic chroman-2-ones containingβ-aryl,alkenyl,alkynyl,and alkyl groups,enabling the synthesis of chiralγ-aryl primary alcohols and the recovery of chiralβ-aryl esters or chroman-2-ones,typically difficult to access using existing *** scalability and broad synthetic applications of this method were exemplified by successfully synthesizing chiral drugs(R)-fesoterodine and enrasentan,alongside various chiral intermediates essential for producing chiral drugs and natural *** promising results highlight the potential of this approach as a powerful tool for synthesizing valuable chiral compounds.

关键词： asymmetric hydrogenation chiralγ-aryl primary alcohols hydrogenation of esters iridium catalysts kinetic resolution

Two-person device-free localization system based on ZigBee and transformer

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Technology Letters 2024年第1期30卷 61-67页

作者：刘天蒙 YANG hai xiao WU Hong School of Electronic Information and Optical Engineering Nankai UniversityTianjin 300350P.R.China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Nankai UniversityTianjin 300350P.R.China Engineering Research Center of Thin Film Optoelectronics Technology Nankai UniversityTianjin 300350P.R.China

Most studies on device-free localization currently focus on single-person *** paper proposes a novel method for device-free localization that utilizes ZigBee received signal strength indication(RSSI)and a Transformer network *** method aims to address the limited research and low accuracy of two-person device-free *** paper first describes the construction of the sensor network used for collecting ZigBee *** then examines the format and features of ZigBee data *** algorithm design of this paper is then *** box plot method is used to identify abnormal data points,and a neural network is used to establish the mapping model between ZigBee RSSI matrix and localization *** neural network includes a Transformer encoder layer as the encoder and a fully connected network as the *** proposed method's classification accuracy was experimentally tested in an online test stage,resulting in an accuracy rate of 98.79%.In conclusion,the proposed two-person localization system is novel and has demonstrated high accuracy.

关键词： device-free localization deep learning ZigBee

Layer Hall effect induced by hidden Berry curvature in antiferromagnetic insulators

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第2期11卷 15-23页

作者： Rui Chen hai-Peng Sun Mingqiang Gu Chun-Bo Hua Qihang Liu hai-Zhou Lu X.C.xie Shenzhen Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology(SUSTech) International Quantum Academy Institute for Theoretical Physics and Astrophysics University of Würzburg School of Electronic and Information Engineering Hubei University of Science and Technology Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Shenzhen Key Laboratory of Quantum Science and Engineering International Center for Quantum Materials School of PhysicsPeking University Collaborative Innovation Center of Quantum Matter CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences

The layer Hall effect describes electrons spontaneously deflected to opposite sides at different layers, which has been experimentally reported in the MnBi2Te4thin films under perpendicular electric fields. Here, we reveal a universal origin of the layer Hall effect in terms of the so-called hidden Berry curvature, as well as material design principles. Hence, it gives rise to zero Berry curvature in momentum space but non-zero layer-locked hidden Berry curvature in real space. We show that, compared to that of a trivial insulator, the layer Hall effect is significantly enhanced in antiferromagnetic topological insulators. Our universal picture provides a paradigm for revealing the hidden physics as a result of the interplay between the global and local symmetries, and can be generalized in various scenarios.

关键词： layerHall effect hidden Berry curvature antiferromagnetic insulator axion insulator, quantum transport