检索结果-南通市图书馆

Phosphine-promoted [3+2] cycloaddition between nonsubstituted MBH carbonates and trifluoromethyl ketones

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2015年第6期26卷 646-648页

作者： Hong-Yu Duan Juan Ma zhe-zhe yuan Ri-Sheng Yao Wei Tao Fang Xu Hua Xiao Gang Zhao School of Medical Engineering Hefei University of Technology Key Laboratory of Synthetic Chemistry of Natural Substances Shanghai Institute of Organic ChemistryChinese Academy of Sciences

A phosphine-promoted [3 ＋ 2] cycloaddition from readily accessible MBH （Morita-Baylis-Hillman） carbonate and aryl trifluoromethyl ketone is described. The use of methyl vinyl ketone-derived allylic carbonate rather than common acrylate-derived counterpart renders the reaction pathway exclusive for 5-endo process, which enables the expeditious preparation of a range of trifluoromethylated 2, 3-dihydrofuran in a chemospecific manner.

关键词： Cycloaddition Allylic carbonate Ylides Trifluorornethyl ketones

Index-free triangle-based graph local clustering

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第3期18卷 143-153页

作者： zhe yuan zhewei WEI Fangrui LV Ji-Rong WEN The Country and Area Studies Academy Beijing Foreign Studies UniversityBeijing 100089China Gaoling School of Artificial Intelligence Renmin University of ChinaBeijing 100872China

Motif-based graph local clustering(MGLC)is a popular method for graph mining tasks due to its various ***,the traditional two-phase approach of precomputing motif weights before performing local clustering loses locality and is impractical for large *** some attempts have been made to address the efficiency bottleneck,there is still no applicable algorithm for large scale graphs with billions of *** this paper,we propose a purely local and index-free method called Index-free Triangle-based Graph Local Clustering(TGLC^(*))to solve the MGLC problem w.r.t.a ***^(*)directly estimates the Personalized PageRank(PPR)vector using random walks with the desired triangleweighted distribution and proposes the clustering result using a standard sweep *** demonstrate TGLC^(*)’s scalability through theoretical analysis and its practical benefits through a novel visualization ***^(*)is the first algorithm to solve the MGLC problem without precomputing the motif *** experiments on seven real-world large-scale datasets show that TGLC^(*)is applicable and scalable for large graphs.

关键词： graph local clustering triangle motif index-free sampling method visualization

Boosting oxygen reduction activity and CO_(2) resistance on bismuth ferrite-based perovskite cathode for low-temperature solid oxide fuel cells below 600℃

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第3期90卷 600-609,I0013页

作者： Juntao Gao Zhiyun Wei Mengke yuan zhe Wang zhe Lü Qiang Li Lingling Xu Bo Wei School of Physics Harbin Institute of TechnologyHarbin 150001HeilongjiangChina Key Laboratory of Functional Inorganic Material Chemistry Ministry of EducationSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080HeilongjiangChina School of Physics and Electronic Engineering Harbin Normal UniversityHarbin 150025HeilongjiangChina

Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical ***,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)FeO_(3-δ) perovskites as highly-active catalysts for *** doping can significantly enhance the electrocata lytic activity and chemical stability of *** 600℃,Bi_(0.675)Sm_(0.025)Sr_(0.3)FeO_(3-δ)(BSSF25) cathode has been found to be the optimum composition with a polarization resistance of 0.098 Ω cm^2,which is only around 22.8% of Bi_(0.7)Sr_(0.3)FeO_(3-δ)(BSF).A full cell utilizing BSSF25 displays an exceptional output density of 790 mW cm^(-2),which can operate continuously over100 h without obvious *** remarkable electrochemical performance observed can be attributed to the improved O_(2) transport kinetics,superior surface oxygen adsorption capacity,as well as O_(2)p band centers in close proximity to the Fermi ***,larger average bonding energy(ABE) and the presence of highly acidic Bi,Sm,and Fe ions restrict the adsorption of CO_(2) on the cathode surface,resulting in excellent CO_(2) *** work provides valuable guidance for systematic design of efficient and durable catalysts for LT-SOFCs.

关键词： Low-temperature solid oxide fuel cell Perovskite cathode DFT calculations CO_(2) tolerance

Deep learning methods for roping defect analysis in aluminum alloy sheets: prediction and grading

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2024年第3期12卷 576-590页

作者： yuan-zhe Hu Ru-Xue Liu Jia-Peng He Guo-Wei Zhou Da-Yong Li State Key Laboratory of Mechanical Systems and Vibration Shanghai Jiao Tong UniversityShanghai200240People’s Republic of China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240People’s Republic of China

Roping is a severe band-like surface defect that occurs in deformed aluminum alloy *** roping prediction and rating are essential for industrial ***,the authors introduced an artificial neural network(ANN)model to efficiently forecast roping behavior across the thickness of large regions with texture *** this study,the previously proposed ANN model for roping prediction is briefly reviewed,and a few-shot learning(FSL)-based method is developed for roping grading with limited *** consider the directionality of the roping patterns,the roping dataset constructed from experimental observations is transformed into the frequency domain for more compact characterization.A transfer-based FSL method is further presented for grade roping with manifold mixup regularization and the Sinkhorn mapping algorithm.A new component-focused representation is also implemented for data-processing,exploiting the close correlation between roping and power distribution in the frequency *** ultimate FSL method achieved an optimal accuracy of 95.65%in roping classification with only five training samples per class,outperforming four typical FSL *** FSL approach can be applied to grade the roping morphologies predicted by the ANN ***,the combination of prediction and grading using deep learning provides a new paradigm for roping analysis and control.

关键词： Roping Artificial neural network(ANN) Aluminum alloys Few-shot classification Surface morphology

Coordinated optimization of signal timing for intersections with dynamic shared through-and right-turn lanes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Intelligent and Connected Vehicles

Journal of Intelligent and Connected Vehicles 2024年第3期7卷 219-228页

作者： zhe zheng Jian yuan Kun An Nan zheng Wanjing Ma The Key Laboratory of Road and Traffic Engineering Ministry of EducationTongji UniversityShanghai 201804China Department of Civil Engineering Monash UniversityMelbourne VIC 3800Australia

Through and right-turn shared lanes are widely designed to increase the capacity of through traffic,but they can also cause delays for right-turn *** study presents a dynamic control method for a shared lane that prioritizes right-turn vehicles at the beginning of the cycle and subsequently allows through traffic to queue in the shared lane for saturated *** traffic wave model is employed to reveal the dynamics of the traffic flow under this control and to derive the relationships among major traffic *** by the major relationship,a linear programming approach to minimize the total queue length is developed to determine the proper values of control parameters,including the shared area length,subordinate signal time lag,and shared or exclusive duration.A sensitivity analysis of the control parameters for different arrival rates and flow ratios is *** are conducted among the dynamic shared lane,the fixed exclusive lane,and the fixed shared *** results show that the dynamic control method results in a lower delay for both through and total traffic.

关键词： traffic control dynamic lane right-turn traffic optimization model

High cerium content(Nd-Pr-Ce)_(2)Fe_(14)B melt-spun ribbons with high coercivity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第4期42卷 690-695页

作者： Yujiang Zhong Junming Wang Zikai yuan Ruijin Liu Minggang Zhu zhe Liu Xin Chen Wei Li Zhaohui Guo Division of Functional Materials Central Iron and Steel Research InstituteBeijing100081China Ningbo Jinji Strong Magnetic Material Co. Ltd.Ningbo315172China Jiangxi Jiangwu Rare Metal New Material Co. Ltd.Nanchang330013China

The effects of wheel speeds on the magnetic properties and microstructures of[(Nd,Pr)_(1-x)Ce_(x)]-Fe-B meltspun ribbons were *** to melt-spun ribbons with low cerium(Ce)content(x=0.2),amorphous formation can be suppressed at high wheel speed in the ribbons with a relatively high Ce content(x=0.8),and with the increase of the wheel speed,the magnetic properties of the ribbons with high Ce content raise *** high wheel speed,the coercivity mechanism of melt-spun ribbons is mainly pinning field,and the high wheel speed introduces a large number of defects into the matrix as pinning ***,ribbons with high Ce content form a fine and uniform grain structure,so the grain boundary area enlarges,which further hinders the movement of domain *** combined effects of the above factors enable ribbons with high Ce content to have excellent magnetic properties(Hcj=0.977 T,Mr=64 m^(2) A/kg)at the wheel speed of 35 m/s.

关键词： Wheel speed Cecontent Microstructure Magnetic properties Rare earths

Research advancement of DNA-based intelligent hydrogels:Manufacture, characteristics, application of disease diagnosis and treatment

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第10期35卷 92-101页

作者： zhe-Han Yang Jie Yin Lei Xin yuanfang Li Yijie Huang Ruo yuan Ying Zhuo Chongqing Key Laboratory of Catalysis and Functional Organic Molecules College of Environment and ResourcesChongqing Technology and Business UniversityChongqing 400067China Key Laboratory of Luminescence and Real-Time Analytic Chemistry(Southwest University) Ministry of EducationCollege of Chemistry and Chemical EngineeringSouthwest UniversityChongqing 400715China

DNA-based hydrogels are exceptional materials for biological applications because of their numerous advantages such as biodegradability,biocompatibility,hydrophilicity,super absorbency,porosity,and *** these advantages,the ability of DNA-based hydrogels to respond to specific physical and chemical triggers and undergo reversible phase transitions has garnered significant attention in the fields of disease diagnosis(biosensors)and treatment(drug delivery).This article focuses on the recent advancements in the research of DNA-based hydrogels and discusses the different types of these hydrogels,the synthetic methods,their unique properties,and their applications in biosensors and drug *** types of DNA hydrogels are categorized based on their building blocks,and the process of synthesis as well as the unique characteristics of DNA-based hydrogels are ***,DNA-based responsive hydrogels utilized as intelligent materials for the development of biosensors are ***,this article also presents the current status of DNA-based responsive hydrogels in drug delivery for cancer treatment,wound healing,and other therapeutic ***,this paper discusses the current challenges in expanding the practical application of DNA-based hydrogels.

关键词： DNA-based hydrogel Intelligent hydrogel Manufacture Characteristics Diseasediagnosis and treatment

Imaging Carotid Plaque Burden in Living Mice via Hybrid Semiconducting Polymer Nanoparticles-Based Near-Infrared-II Fluorescence and Magnetic Resonance Imaging

在线全文

学校读者我要写书评

暂无评论

Research 2024年第3期2023卷 71-81页

作者： Li Xu zhe Li yuan Ma Lingling Lei Renye Yue Hui Cao Shuangyan Huan Wei Sun Guosheng Song State Key Laboratory for Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical EngineeringEngineeringHunan UniversityChangsha 410082China. Key Laboratory of Targeted Intervention of Cardiovascular Disease Collaborative Innovation Center for Cardiovascular Disease Translational MedicineNanjingMedical University Department of Cardiology The First Affiliated Hospital of Nanjing Medical UniversityNanjing Medical UniversityNanjing 210029JiangsuChina.

The majority of atherothrombotic events (e.g., cerebral or myocardial infarction) often occur as a result of plaque rupture or erosion in the carotid, and thereby it is urgent to assess plaque vulnerability and predict adverse cerebrovascular events. However, the monitoring evolution from stable plaque into life-threatening high-risk plaque in the slender carotid artery is a great challenge, due to not enough spatial resolution for imaging the carotid artery based on most of reported fluorescent probes. Herein, copolymerizing with the small molecules of acceptor-donor-acceptor-donor-acceptor (A-D-A′-D-A) and the electron-donating units (D′), the screened second near-infrared (NIR-II) nanoprobe presents high quantum yield and good stability, so that it enables to image slender carotid vessel with enough spatial resolution. Encouragingly, NIR-II nanoprobe can effectively target to intraplaque macrophage, meanwhile distinguishing vulnerable plaque in carotid atherosclerosis in living mice. Moreover, the NIR-II nanoprobe can dynamically monitor the fresh bleeding spots in carotid plaque, indicating the increased risk of plaque instability. Besides, magnetic resonance imaging is integrated with NIR-II fluorescence imaging to provide contrast for subtle structure (e.g., narrow lumen and lipid pool), via incorporating ultrasmall superparamagnetic iron oxide into the NIR-II nanoprobe. Thus, such hybrid NIR-II/magnetic resonance imaging multimodal nanoprobe provides an effective tool for assessing carotid plaque burden, selecting high-risk plaque, and imaging intraplaque hemorrhage, which is promising for reducing cerebral/ myocardial infarction-associated morbidity and mortality.

关键词： enough conducting Infrared

Morphology effect on catalytic performance of ebullated-bed residue hydrotreating over Ni-Mo/Al_(2)O_(3)catalyst:a kinetic modeling study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green Chemical Engineering 2024年第1期5卷 60-67页

作者： zhe Liu Juncong yuan Zongzhuang Sun Xiang Feng Yibin Liu Huihong Zhu Chong Peng Chaohe Yang State Key Laboratory of Heavy Oil Processing China University of PetroleumQingdao266580China Dalian Research Institute of Petroleum and Petrochemicals SINOPECDalian116045China State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalian116024China

Upgrading of vacuum residue is of prime industrial significance due to the increasing demand for light *** the effect of catalyst morphology on vacuum residue hydrotreating performance by kinetic modeling is therefore of great ***,kinetic analysis of hydrodemetallization(HDM)and hydrodeconradsoncarbon-residue(HDCCR)performances on industrial Ni-Mo/Al_(2)O_(3)catalysts with spherical and cylindrical morphologies in ebullated-bed were evaluated for more than 1600 *** was found that the percentage of light impurities easier to be removed on spherical catalysts were 78.20%and 39.43%in HDM and HDCCR reactions,respectively,higher than 65.20%and 17.50%on cylindrical *** suggests that catalyst morphology affects the impurity removal ability and the impurity properties,resulting in better hydrotreating performance of spherical *** work not only combines catalyst morphology with impurity removal capability through kinetic modeling,but also provides new insights into the design of efficient hydrotreating catalysts.

关键词： Morphology effect Kinetic analysis Vacuum residue Hydrotreating