检索结果-南通市图书馆

Synthesis and Characterization of a Novel Liquid Crystalline Chitin Quaternary Ammonium Chitosan Salt

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2003年第4期19卷 512-515页

作者： RUAN Yong-hong dong yan-ming WU ming-shui ZENG Man-qing WANG Shui-ju Department of Materials Science and Engineering Xiamen UniversityXiamen 361005P.R.China

N -Butyl chitosan(NBCS) derivatives were prepared by introducing butyl groups into the amine groups of chitosan via Schiff base intermediates. The quaternization of NBCS was carried out by using ethyl iodide to produce water-soluble cationic polyelectrolytes. The degree of the substitution of the products was measured by means of the electron spectroscopy for a successful chemical analysis. The quaternary ammonium chitosan salt(QACS) was proved to be a novel cholesteric liquid crystalline chitin, by means of the polarized optical microscopy and the circular dichroism spectropolarimetry. The critical mass fraction of the QACS/formic acid solution forming a lyotropic liquid crystal phase was 50%, which was almost the same as that of the NBCS/formic acid solution, but much higher than that of the chitosan in the same solvent.

关键词： Quaternary ammonium chitosan Cholesteric liquid crystal ESCA CD spectropolarimetry

Fast and Error-Bounded Space-Variant Bilateral Filtering

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2019年第3期34卷 550-568页

作者： Meng-Ke Yuan Long-Quan Dai dong-ming yan Li-Qiang Zhang Jun Xiao Xiao-Peng Zhang National Laboratory of Pattern Recognition Institute of AutomationChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China School of Computer Science and Technology Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Remote Sensing Science School of GeographyBeijing Normal UniversityBeijing 100875China

The traditional space-invariant isotropic kernel utilized by a bilateral filter(BF)frequently leads to blurry edges and gradient reversal artifacts due to tlie existence of a large amount of outliers in the local averaging ***,the efficient and accurate cstiinatioii of space-variant k(4rnels which adapt to image structures,and the fast realization of the corresponding space-variant bilateral filtering are challenging *** address these problems,we present a space-variant BF(SVBF).and its linear time and error-bounded acceleration ***,we accurately estimate spacevariant,anisotropic kernels that vary with image structures in linear time through structure tensor and mininnini spanning ***,we perform SVBF in linear time using two error-bounded approximation methods,namely,low-rank tensor approximation via higher-order singular value decomposition and exponential sum *** proposed SVBF can efficiently achieve good edge-preserving *** validate the advantages of the proposed filter in applications including:image denoising,image enhancement,and image focus *** results(leinonstrate that our fast and error-bounded SVBF is superior to state-of-the-art methods.

关键词： error-bounded acceleration edge-aware smoothing space-variant bilateral filtering

Structure regulating of metal clusters in carbonized metallic organic frameworks for high-efficient microwave absorption via tuning interaction strength between metals and ligands

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3期17卷 1699-1709页

作者： Chang Sun Kun-yan Zhao ming-Lu Huang Cheng-Long Luo Xu-dong Chen ming Wang School of Chemistry and Chemical Engineering Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function ManufacturingSouthwest UniversityChongqing 400715China Jieyang Branch of Chemistry and Chemical Engineering Guangdong Laboratory(Rongjiang Laboratory) Jieyang 515200China

Carbonized metallic organic frameworks(CMOF)have been attracting attention in microwave absorption(MA)research area because of their diverse structures,tunable compositions,and rich ***,structure regulation on metal clusters in CMOF is achieved by tuning the interaction strength between metals and ligands to enhance microwave absorption *** to relatively weak interaction among copper cations and ligands,copper nanoclusters(CuNC)can be uniformly formed and embedded within the cobalt/zinc(Co/Zn)***,copper cations are added to the Co/Zn bimetallic zeolitic imidazolate frameworks(ZIFs).Secondly,the CMOF composite particles with CuNCs(CuNCs/CoZn-CMOF)were developed by a pyrolysis *** CuNCs/CoZn-CMOF with an appropriate amount of CuNCs can harmonize both dielectric and magnetic *** a result,the minimum reflection loss(RLmin)reaches–45.1 dB at a matching thickness of 2.30 mm and the effective absorption bandwidth(EAB)is 8.80 GHz at a thickness of 3.10 *** broadband response to electromagnetic waves is attributed to interfacial polarization at CuNCs surface and heterogeneous interfaces,impedance matching and multiple scattering of electromagnetic *** study provides a feasible method to develop CMOF microwave absorption materials with high EAB values.

关键词： heterogeneous interface carbonized metallic organic frameworks microwave absorption interfacial polarization

Drying Shrinkage of Cement-Based Materials Under Conditions of Constant Temperature and Varying Humidity

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 China University of Mining and Technology 2007年第3期17卷 428-431页

作者： MA Bao-guo WEN Xiao-dong WANG ming-yuan yan Jia-jia Gao Xiao-jian Key Laboratory for Silicate Materials Science and Engineering of Ministry of Education Wuhan University of Technology Wuhan Hubei 430070 China

Currently,deformations along the central axis of specimens were usually measured under fixed environmental conditions. Seldom were the effects of environmental factors on the drying-shrinkage deformation of cement-based ma-terial considered. For this paper,the drying-shrinkage deformation at different w/b ratios and different additions to mor-tars was investigated under different environments at a temperature of 20 ℃ and humidity ranging from 100% to 50%. The specimens were cured in water for 28 days before measurement. The results illustrate that mortar shows much less shrinkage under various drying conditions when a lower w/b ratio is adopted. With a decrease in relative humidity the speed of drying-shrinkage becomes gradually lower. The addition of silica fume reduces the drying-shrinkage of mortar under higher relative humidity,because the pore structure of mortar with silica fume becomes more refined. The addi-tion of fly ash increases the total porosity and the volume of coarse pores in the mortar. The drying-shrinkage of mortar under different conditions increases with the addition of more of fly ash.

关键词： humidity variation volume deformation pore structure

Two-Staged Method for Ice Channel Identification Based on Image Segmentation and Corner Point Regression

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2024年第2期38卷 313-325页

作者： dong Wen-bo ZHOU Li DING Shi-feng WANG Ai-ming CAI Jin-yan School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Identification of the ice channel is the basic technology for developing intelligent ships in ice-covered waters,which is important to ensure the safety and economy of *** the Arctic,merchant ships with low ice class often navigate in channels opened up by *** in the ice channel often depends on good maneuverability skills and abundant experience from the captain to a large *** ship may get stuck if steered into ice fields off the *** this circumstance,it is very important to study how to identify the boundary lines of ice channels with a reliable *** this paper,a two-staged ice channel identification method is developed based on image segmentation and corner point *** first stage employs the image segmentation method to extract channel *** the second stage,an intelligent corner regression network is proposed to extract the channel boundary lines from the channel region.A non-intelligent angle-based filtering and clustering method is proposed and compared with corner point regression *** training and evaluation of the segmentation method and corner regression network are carried out on the synthetic and real ice channel *** evaluation results show that the accuracy of the method using the corner point regression network in the second stage is achieved as high as 73.33%on the synthetic ice channel dataset and 70.66%on the real ice channel dataset,and the processing speed can reach up to 14.58frames per second.

关键词： ice channel ship navigation identification image segmentation corner point regression

Long non-coding RNA MEG3 regulates autophagy after cerebral ischemia/reperfusion injury

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2022年第4期17卷 824-831页

作者： Tian-Hao Li Hong-Wei Sun Lai-Jun Song Bo yang Peng Zhang dong-ming yan Xian-Zhi Liu Yu-Ru Luo Department of Neurosurgery The First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan ProvinceChina

Severe cerebral ischemia/reperfusion injury has been shown to induce high-level autophagy and neuronal ***,it is extremely important to search for a target that inhibits autophagy *** non-coding RNA MEG3 participates in ***,it remains unclear whether it can be targeted to regulate cerebral ischemia/reperfusion *** results revealed that in oxygen and glucose deprivation/reoxygenation-treated HT22 cells,MEG3 expression was obviously upregulated,and autophagy was increased,while knockdown of MEG3 expression greatly reduced ***,MEG3 bound mi R-181 c-5 p and inhibited its expression,while mi R-181 c-5 p bound to autophagy-related gene ATG7 and inhibited its *** experiments revealed that mir-181 c-5 p overexpression reversed the effect of MEG3 on autophagy and ATG7 expression in HT22 cells subjected to oxygen and glucose deprivation/*** vivo experiments revealed that MEG3 knockdown suppressed autophagy,infarct volume and behavioral deficits in cerebral ischemia/reperfusion *** findings suggest that MEG3 knockdown inhibited autophagy and alleviated cerebral ischemia/reperfusion injury through the mi R-181 c-5 p/ATG7 signaling ***,MEG3 can be considered as an intervention target for the treatment of cerebral ischemia/reperfusion *** study was approved by the Animal Ethics Committee of the First Affiliated Hospital of Zhengzhou University,China(approval ***20190538)on January 4,2019.

关键词： ATG7 autophagy cerebral infarction cerebral ischemia/reperfusion injury long non-coding RNA miR-181c-5p neuron oxygen and glucose deprivation/reoxygenation

活性瓷釉涂层钢筋及钢纤维增强混凝土板动、静力学特性研究（英文）

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2016年第5期17卷 366-377页

作者： dong-ming yan Shi-kun CHEN Gen-da CHEN Jason BAIRD School of Civil and Architectural Engineering Zhejiang University Department of Civil Architectural and Environmental Engineering Missouri University of Science and Technology

目的:活性瓷釉涂层能够显著增强钢筋的防腐蚀能力,同时明显提升钢筋与混凝土的粘结力。通过对活性瓷釉涂层钢筋以及钢纤维增强混凝土板在动、静力荷载作用下的承载力、变形特性以及破坏特征的研究,为活性瓷釉涂层技术在钢筋混凝土结构... 详细信息

目的:活性瓷釉涂层能够显著增强钢筋的防腐蚀能力,同时明显提升钢筋与混凝土的粘结力。通过对活性瓷釉涂层钢筋以及钢纤维增强混凝土板在动、静力荷载作用下的承载力、变形特性以及破坏特征的研究,为活性瓷釉涂层技术在钢筋混凝土结构中的应用奠定理论基础。创新点:1.对活性瓷釉涂层钢筋混凝土板的动、静力学性能进行系统研究;2.探究活性瓷釉钢纤维在混凝土结构中的作用机理。方法:1.通过对活性瓷釉涂层钢筋混凝土板进行爆炸实验(图3),揭示活性瓷釉涂层钢筋混凝土结构的动力破坏特征(图5和6);2.通过对活性瓷釉涂层钢筋混凝土板进行静力实验(图4),研究在"点"荷载和"线"荷载作用下混凝土板的力学性能;3.通过分析钢纤维在钢筋混凝土结构中的传力机理,提出活性瓷釉涂层钢纤维在钢筋混凝土结构中的设计方法(图13)。结论:1.活性瓷釉涂层能够显著改善钢筋在混凝土结构中的传力性能;在动力荷载作用下,涂层钢筋混凝土结构的破坏程度明显减轻。2.活性瓷釉涂层能够显著改善钢筋混凝土结构的变形特性,大大增强其耗能能力。3.采用活性瓷釉涂层的钢纤维,其纤维长度可适当减小。

关键词：活性瓷釉涂层爆炸荷载破坏特征钢纤维

Meta-path reasoning of knowledge graph for commonsense question answering

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第1期18卷 49-59页

作者： Miao ZHANG Tingting HE ming dong National Engineering Research Center for E-Learning Central China Normal UniversityWuhan 430079China Hubei Provincial Key Laboratory of Artificial Intelligence and Smart Learning Central China Normal UniversityWuhan 430079China National Language Resources Monitoring&Research Center for Network Media Central China Normal UniversityWuhan 430079China School of Computer Central China Normal UniversityWuhan 430079China

Commonsense question answering(CQA)requires understanding and reasoning over QA context and related commonsense knowledge,such as a structured Knowledge Graph(KG).Existing studies combine language models and graph neural networks to model ***,traditional knowledge graph are mostly concept-based,ignoring direct path evidence necessary for accurate *** this paper,we propose MRGNN(Meta-path Reasoning Graph Neural Network),a novel model that comprehensively captures sequential semantic information from concepts and *** MRGNN,meta-paths are introduced as direct inference evidence and an original graph neural network is adopted to aggregate features from both concepts and paths *** conduct sufficient experiments on the CommonsenceQA and OpenBookQA datasets,showing the effectiveness of ***,we conduct further ablation experiments and explain the reasoning behavior through the case study.

关键词： question answering knowledge graph graph neural network meta-path reasoning

Blast response of full-size concrete walls with chemically reactive enamel （CRE）-coated steel reinforcement

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 Zhejiang University-Science A(Applied Physics & Engineering) 2016年第9期17卷 689-701页

作者： dong-ming yan Hua-wei YIN Cheng-lin WU yan-long LI Jason BAIRD Gen-da CHEN School of Civil and Architectural Engineering Zhejiang University Hangzhou 310058 China College of Civil Engineering Hunan University Changsha 410082 China Department of Civil Architectural and Environmental Engineering Missouri University of Science and Technology Rolla 654009 USA State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area Xi'an University of Technology Xi'an 710048 China Rock Mechanics and Explosives Missouri University of Science and Technology Rolla 654009 USA Center for Infrastructure Engineering Studies Missouri University of Science and Technology Rolla 654009 USA

In this study, two full-size concrete wails were tested and analyzed to demonstrate the effectiveness of a chemically reactive enamel （CRE） coating in improving their mechanical behavior under blast loading： one with CRE-coated rebar and the other with uncoated rebar. Each wall was subjected in sequence to four explosive loads with equivalent 2, 4, 6-trinitrotoluene （TNT） charge weights of 1.82, 4.54, 13.6, and 20.4 kg. A finite element model of each wall under a close-in blast load was developed and validated with pressure and strain measurements, and used to predict rebar stresses and concrete surface sWain distributions of the wall. The test results and visual inspections consistently indicated that, compared with the barrier wall with uncoated reinforcement, the wall with CRE-coated rebar has fewer concrete cracks on the front and back faces, more effective stress transfers from concrete to steel rebar, and stronger connections with its concrete base. The concrete surface strain distributions predicted by the model under various loading conditions are in good agreement with the crack patterns observed during the tests.

关键词： Chemically reactive enamel (CRE) coating Blast loading Crack pattern Bond strength Finite element model