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Fluorescent carbon dots synthesized in solid phase and air for application in LEDs

Nano Research 2024年第9期17卷 8495-8503页

作者： Wei-Jie Zheng Zhao-Nan Sun Yi-ming wang Huan-ming Xiong Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Fudan UniversityShanghai 200438China

Carbon dots(CDs)have been widely adopted as optical materials because of their excellent luminescent ***,most of the reported synthetic methods are conducted in solvents,especially hydrothermal/solvothermal reactions,leading to intractable problems such as toxic and flammable solvents,complex and inseparable by-products,and dangerously high pressures and ***-phase synthesis of CDs in air is an effective solution to overcome the above issues,but solid reactions always result in uncontrolled growth and agglomeration of *** this study,some inorganic salts are selected as catalysts for synthesizing CDs in solid states and air,which also play as dispersants to hinder CDs *** the meantime,some aromatic derivatives containing hydroxyl and amino groups are chosen as carbon sources,ground with the optimized catalyst,and then heated together in *** production yields are affected by the reaction time and reactant ratio,while the graphitization degrees of the CDs are determined by the reaction *** IG/ID value of their Raman spectra increases from 0.59 to 0.85,and the particle size decreases from 2.5 to 1.4 nm when the synthesis temperature is increased from 200 to 280℃.The as-prepared CDs show emission peaks ranging from 366 to 606 nm,with the photoluminescence(PL)quantum yield up to 53%.Their emission color variation mainly results from different carbon sources,which can be ascribed to the differences in the element composition,functional groups,and graphitic nitrogen content of these *** dispersing CDs of different concentrations into polyvinyl alcohol(PVA)and combining them with blue LEDs,cold,standard,and warm white light emitting devices(WLEDs)are prepared,with a color rendering index(CRI)up to *** the as-prepared CDs have antioxidant ability at high temperature,the as-prepared WLEDs have long lifespans,remaining the effective white luminescence after 72 h continuous work.

关键词： carbon dot solid-phase synthesis white LED photoluminescence inorganic salt catalysis

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Vibration reduction analysis of new barriers in large model experiment

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Earthquake Engineering and Engineering Vibration 2022年第3期21卷 741-751页

作者： Ding Guangya Shen Chenli wang Jun Wu ming College of Civil Engineering and Architecture Wenzhou UniversityWenzhou 325035China School of Geological Engineering and Surveying Chang’an UniversityXi’an 710054China

A large model box was developed in our experiment to study the vibration reduction *** hydraulic highperformance actuators are arranged in the upper part of the model *** is a time difference between adjacent actuators,which can simulate the train induced *** reduce vibration a composite barrier is designed;the barrier consists of a honeycomb concrete canvas and PE polymer water *** concrete canvas can be mixed with water to produce a hydration reaction to form a structure with a certain *** simulating different train speeds and loads,vertical vibration velocity,and acceleration before and after the barrier are compared and *** experimental results show that the new barrier can achieve a good vibration reduction *** the simulated train speed increases,the damping effect of the barrier is *** a speed of 180 km/h,an amplitude of 1.5 m after the barrier is found to be 48.6%lower than that before the *** decreases by 24.2%at 36 km/h and by 38.1%at 108 km/h.

关键词： vibration reduction traffic loads test barrier concrete canvas

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Bayesian Network Based Imprecise Probability Estimation Method for Wind Power Ramp Events

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Journal of Modern Power Systems and Clean Energy 2021年第6期9卷 1510-1519页

作者： Yuanchun Zhao Wenli Zhu ming Yang Mengxia wang Key Laboratory of Power System Intelligent Dispatch and Control Shandong University State Grid Jinan Power Company

Although wind power ramp events(WPREs)are relatively scarce,they can inevitably deteriorate the stability of power system operation and bring risks to the trading of electricity *** this paper,an imprecise conditional probability estimation method for WPREs is proposed based on the Bayesian network(BN)*** method uses the maximum weight spanning tree(MWST)and greedy search(GS)to build a BN that has the highest fitting degree with the observed ***,an extended imprecise Dirichlet model(IDM)is developed to estimate the parameters of the BN,which quantificationally reflect the ambiguous dependencies among the random ramp event and various meteorological *** BN is then applied to predict the interval probability of each possible ramp state under the given meteorological conditions,which is expected to cover the target probability at a specified confidence *** proposed method can quantify the uncertainty of the probabilistic ramp event ***,by using the extracted dependencies and Bayesian rules,the method can simplify the conditional probability estimation and perform reliable prediction even with scarce *** results on a real wind farm with three-year operation data illustrate the effectiveness of the proposed method.

关键词： Bayesian network(BN) conditional probability imprecise Dirichlet model(IDM) imprecise probability wind power ramp events

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Robust spline-line energy management guidance algorithm with multiple constraints and uncertainties for solid rocket ascending

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Chinese Journal of Aeronautics 2022年第2期35卷 214-234页

作者： Songyan wang Fei LIU Tao CHAO ming YANG Control and Simulation Center Harbin Institute of TechnologyHarbin 150001China

For the solid rocket with depletion shutdown system,effective energy management is significant to meet terminal constraints by exhausting excess *** traditional energy management algorithms cannot satisfy the altitude constraint and path constraints are not sufficiently *** velocity adjustment capability of these algorithms is limited and the uncertainties are not *** on the on-line programming of velocity capability curve,Spline-Line Energy Management(SLEM)guidance algorithm is *** introduces lateral maneuvers to further consume the available velocity on the basis of longitudinal energy *** expressing the constraints as several algebraic equations,the closed-loop guidance problem is converted to solving a system of nonlinear equations about the curve parameters in real *** advantage is that the altitude constraint can be satisfied *** overload and control variable change rate and amplitude constraints are also considered during the flight by constructing the feasible boundary of velocity capability *** improve the robustness,it is further extended by estimating the actual *** effectiveness and advantages of SLEM are demonstrated by simulations and comparisons with other energy management *** results show that the proposed approach can satisfy multiple constraints with high precision under the condition of uncertainties.

关键词： Ascent guidance Energy management Multiple constraints Solid rockets Uncertainty Velocity capability curve

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Experimental research on the contact force of the bi-directional pig in oil and gas pipeline

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Petroleum Science 2023年第1期20卷 474-481页

作者： Xiao-Xiao Zhu Chun-ming Fu Yu-Tao wang Shi-ming Zhang College of Mechanical and Transportation Engineering China University of Petroleum-BeijingChangpingBeijing102249China

The migration process of the pig in oil and gas pipeline is a complex dynamic *** the pigging operation,the variation of friction force caused by the nonlinear contact between the sealing disc and the pipe wall is the key factor affecting the dynamic characteristics of the pig *** present,the existed pigging models for predicting pigging behavior regard friction as an invariant *** research indicates that the friction force of the pig varies with the contact force and the lubrication ***,the assumption that the friction force is constant cannot reflect the friction dynamic characteristics of the pig during pigging,and will also affect the accuracy of the pigging *** the variation of friction force of pig under different conditions is the basis of establishing the transient dynamic model of a *** a result,in this paper,a method of direct measurement of contact force between the pig and the pipeline is presented,the contact force,the friction force,as well as the friction coefficient of the pig are obtained from the *** results in this paper can help to establish a more accurate dynamic model of pig.

关键词： Pipeline pig Sealing disc Contact force Friction coefficient Experimental rig

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Insertion of Supramolecular Segments into Covalently Crosslinked Polyurethane Networks towards the Fabrication of Recyclable Elastomers

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Chinese Journal of Polymer Science 2022年第3期40卷 321-330,I0009页

作者： Lu-Ping wang ming-Guang Zhang Jing-Cheng Hao Xu wang National Engineering Research Center for Colloidal Materials School of Chemistry and Chemical EngineeringShandong UniversityJinan 250100China Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education School of Chemistry and Chemical EngineeringShandong UniversityJinan 250100China

Thermoset plastics have become one of the most important chemical products in the world. The consequent problem is that although the thermosets possess excellent performance in mechanical strength, they cannot be reprocessed because of the internal permanent network structures. Optimizing the molecular design of thermosets is one of the most feasible ways to improve their recyclability. Here we present a facile and robust strategy to engineer the reprocessability of thermoset polyurethanes without compromising their mechanical toughness and chemical resistance via adding supramolecular additives during the polymer synthesis process. By using a multiple hydrogen bonding moiety as the model supramolecular additive, we demonstrate that the mechanical properties, recyclability, and chemical resistance of the crosslinked polyurethanes can be precisely controlled by adjusting the contents of the supramolecular additive. Systematic studies on the relations between molecular design and material properties are performed, and the optimized polyurethane network with a moderate amount of the supramolecular additive achieves the right balance between the robustness and recyclability. This work provides a cost-effective and practical way to chemically engineer thermoset plastics, aiming to enable the recycling of mechanically tough and chemically stable polymer materials.

关键词： Thermoset plastics Recyclability Polyurethane Supramolecular additives Chemical resistance

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Fine-Grained Opinion Extraction from Chinese Car Reviews with an Integrated Strategy

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Journal of Shanghai Jiaotong university(Science) 2018年第5期23卷 620-626页

作者： wang Yinglin wang ming School of Information Management and Engineering Shanghai University of Finance and EconomicsShanghai 200433China

With rapid development of E-commerce, a large amount of data including reviews about different types of products can be accessed within short time. On top of this, opinion mining is becoming increasingly effective to extract valuable information for product design, improvement and brand marketing, especially with fine-grained opinion mining. However, limited by the unstructured and causal expression of opinions, one cannot extract valuable information conveniently. In this paper, we propose an integrated strategy to automatically extract feature-based information, with which one can easily acquire detailed opinion about certain *** adaptation to the reviews' characteristics, our strategy is made up of a multi-label classification(MLC) for reviews, a binary classification(BC) for sentences and a sentence-level sequence labelling with a deep learning method. During experiment, our approach achieves 82% accuracy in the final sequence labelling task under the setting of a 20-fold cross validation. In addition, the strategy can be expediently employed in other reviews as long as there is an according amount of labelled data for startup.

关键词： opinion extraction multi-label classification (MLC) binary classification (BC) sequence labelling recurrent neural network (RNN)

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Joint salient object detection and existence prediction

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Frontiers of Computer Science 2019年第4期13卷 778-788页

作者： Huaizu JIANG ming-ming CHENG Shi-Jie LI Ali BORJI Jingdong wang College of Information and Computer Sciences University of Massachusetts Amherst Amherst MA 01003 USA CCCE Nankai University Jinnan Campus Tianjin 300353 China Center for Research in Computer Vision University of Central Florida Orlando FL 32816 USA Microsoft Research Beijing 100080 China

Recent advances in supervised salient object detection modeling has resulted in significant performance improvements on benchmark datasets. However, most of the existing salient object detection models assume that at least one salient object exists in the input image. Such an assumption often leads to less appealing saliency maps on the background images with no salient object at all. Therefore, handling those cases can reduce the false positive rate of a model. In this paper, we propose a supervised learning approach for jointly addressing the salient object detection and existence prediction problems. Given a set of background-only images and images with salient objects, as well as their salient object annotations, we adopt the structural SVM framework and formulate the two problems jointly in a single integrated objective function: saliency labels of superpixels are involved in a classification term conditioned on the salient object existence variable, which in turn depends on both global image and regional saliency features and saliency labels assignments. The loss function also considers both image-level and regionlevel mis-classifications. Extensive evaluation on benchmark datasets validate the effectiveness of our proposed joint approach compared to the baseline and state-of-the-art models.

关键词： salient object detection existence prediction joint inference saliency detection

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Multicentric Gliomas Misdiagnosed as Metastatic Tumors： One Case Report and Literature Review

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Clinical oncology and cancer researeh 2010年第5期7卷 317-321页

作者： Peng wang ming-can WU Shi-jie CHEN Yong YMNG Guang-rui ZHAO Department of Experimental Surgery Yangtze University Clinical Medical College Jingzhou 434000 Hubei Province China. Department of Neurosurgery the First People's Hospital of Jingzhou Jingzhou 434000 Hubei Province China.

Multicentric gliomas are considered to be well recognized but uncommon; often scatter widely in different lobes or hemispheres; and cannot be attributed to a definite pathwayEll. A patient diagnosed as multicentric gliomas is presented in this paper. He was firstly misdiagnosed as cerebral metastatic tumors, but later the histopathological examination revealed them to be glioblastoma （WHO grade IV）. Additionally, the aim of the paper was to describe the case history of the patient and the problems encountered in the pathogenesis, pathophysiology, diagnosis and treatment.

关键词： multicentric gliomas glioblastoma treatment diagnosis.

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Lattice distortion and magnetic property of high entropy alloys at low temperatures

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Journal of Materials Science & Technology 2022年第9期104卷 236-243页

作者： Yuan-Yuan Tan Zhong-Jun Chen ming-Yao Su Gan Ding Min-Qiang Jiang Zhou-can Xie Yu Gong Tao Wu Zhong-Hua Wu Hai-Ying wang Lan-Hong Dai State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China Institute of High Energy Physics Chinese Academy of Sciences&GraduateUniversity of Chinese Academy of SciencesBeijing 100049China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Zhejiang Institute of Mechanical&Electrical Engineering Hangzhou 310053China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

Deformation mechanisms and magnetic properties of medium and high entropy alloys(MEA/HEAs)closely relate to lattice distortion and are strongly temperature-dependent,in particular,at low temperature ***,little attention has been paid to the evolution of lattice distortion with temperature decreasing and its effects on deformation behavior and magnetic state *** this work,we carry out in situ synchrotron radiation based X-ray powder diffraction(SR-XRD)experiments from 293 to 123 K aiming for determining lattice distortion evolutions of Cr Co Ni MEA,Cr Fe Co Ni and Cr Mn Fe Co Ni *** measurements at corresponding low temperatures and cryogenic ranges are further *** in situ SR-XRD results demonstrate a general reduction of lattice distortion magnitude with temperature decreasing,which shows a similar tendency with that of reported stacking fault energy(SFE)*** is thus suggested that lattice distortion reduction possibly makes a critical contribution to deformation mechanism *** magnetic measurement results show a clear ferromagnetic transition of Cr Fe Co Ni HEA when temperature is below 173 ***,no obvious magnetic state transition is observed for Cr Co Ni MEA and Cr Mn Fe Co Ni *** present findings on lattice distortion evolutions will pave the way for designing targeted HEAs with particular properties.

关键词： High entropy alloy Lattice distortion Magnetic property Low temperature In situ SR-XRD

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