检索结果-南通市图书馆

science China Chemistry 2011年第4期54卷 678-684页

作者： LIU DeAng GIBsON Gary BRUG James LAM sity mao samuel s Lawrence Berkeley National Laboratory and Department of Mechanical Engineering University of CaliforniaBerkeleyCAUSA Information surfaces Lab Hewlett Packard LabsHewlett Packard Company1501 Page Mill RoadPalo AltoCA 94304USA

A series of phosphine oxide-functionalized polyfluorene derivatives,PFH-PO-40-1 (P1),PFH-PO-20-1 (P2),PFH-PO-10-1 (P3),and PFH-PO-1-1 (P4),were prepared via a palladium-mediated suzuki cross-coupling *** structures and purities of all polymers were fully characterized by 1H and 13C NMR,UV-vis and photoluminescent spectroscopy,gel permeation chromatography,and TGA/*** emission features showed single broad peaks at about 445 nm in film,compared with those in dilute solutions,which might be caused by some degree of aggregation in the excited states of the *** best electroluminescence (EL) performance of these polymers with configuration of ITO/PEDOT:Pss/Polymer/Alq3/LiF/Al was obtained from P1 (current efficiency was 4.2 Cd/A at 6V).

关键词：电致发光性能聚芴衍生物电化学性能官能化氧化膦光物理凝胶渗透色谱法聚合物结构

single-atom Pt on carbon nanotubes for selective electrocatalysis

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第1期6卷 63-71页

作者： samuel s.Hardisty Xiaoqian Lin Anthony R.J.Kucernak David Zitoun Department of Chemistry Bar Ilan Institute of Nanotechnology and Advanced Materials(BINA)Bar Ilan UniversityRamat GanIsrael Department of Chemistry Molecular Science Research HubImperial College LondonLondonUK

Utilizing supported single atoms as catalysts presents an opportunity to reduce the usage of critical raw materials such as platinum,which are essential for electrochemical reactions such as hydrogen oxidation reaction(HOR).Herein,we describe the synthesis of a Pt single electrocatalyst inside single-walled carbon nanotubes(sWCNTs)via a redox *** via electron microscopy,X-ray photoelectron microscopy,and X-ray absorption spectroscopy show the single-atom nature of the *** electrochemical behavior of the sample to hydrogen and oxygen was investigated using the advanced floating electrode technique,which minimizes mass transport limitations and gives a thorough insight into the activity of the *** single-atom samples showed higher HOR activity than state-of-the-art 30%Pt/C while almost no oxygen reduction reaction activity in the proton exchange membrane fuel cell operating *** selective activity toward HOR arose as the main fingerprint of the catalyst confinement in the sWCNTs.

关键词： confinement electrocatalysis hydrogen platinum single atom catalysts

Equilibrium strategy of the Pursuit-Evasion Game in Three-Dimensional space

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica sinica 2024年第2期11卷 446-458页

作者： Nuo Chen Linjing Li Wenji mao school of Artificial Intelligence University of Chinese Academy of SciencesBeijing 100049 Institute of Automation Chinese Academy of SciencesBeijing 100190China

The pursuit-evasion game models the strategic interaction among players, attracting attention in many realistic scenarios, such as missile guidance, unmanned aerial vehicles, and target defense. Existing studies mainly concentrate on the cooperative pursuit of multiple players in two-dimensional pursuit-evasion games. However, these approaches can hardly be applied to practical situations where players usually move in three-dimensional space with a three-degree-of-freedom control. In this paper,we make the first attempt to investigate the equilibrium strategy of the realistic pursuit-evasion game, in which the pursuer follows a three-degree-of-freedom control, and the evader moves freely. First, we describe the pursuer's three-degree-of-freedom control and the evader's relative coordinate. We then rigorously derive the equilibrium strategy by solving the retrogressive path equation according to the Hamilton-Jacobi-Bellman-Isaacs(HJBI) method, which divides the pursuit-evasion process into the navigation and acceleration phases. Besides, we analyze the maximum allowable speed for the pursuer to capture the evader successfully and provide the strategy with which the evader can escape when the pursuer's speed exceeds the threshold. We further conduct comparison tests with various unilateral deviations to verify that the proposed strategy forms a Nash equilibrium.

关键词： Differential game equilibrium strategy pursuit-evasion game threedegree-of-freedom control

Amorphous oxide semiconductor for monolithic 3D DRAM: an enabler or passer-by?

在线全文

学校读者我要写书评

暂无评论

National science Review 2024年第3期11卷 19-20页

作者： shujuan mao Guilei Wang Chao Zhao Beijing superstring Academy of Memory Technology

since dynamic random-access memory(DRAM) was invented in 1968 and put to market in the 1970s, 1 transistor plus 1 capacitor(1T1C)(Fig. 1a) cells have been used to take advantage of their structural simplicity and ease...

关键词：

Parametric resonance of axially functionally graded pipes conveying pulsating fluid

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 239-260页

作者： Jie JING Xiaoye mao Hu DING Liqun CHEN shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

Based on the generalized Hamilton's principle,the nonlinear governing equation of an axially functionally graded(AFG)pipe is *** non-trivial equilibrium configuration is superposed by the modal functions of a simply supported *** the direct multi-scale method,the response and stability boundary to the pulsating fluid velocity are solved analytically and verified by the differential quadrature element method(DQEM).The influence of Young's modulus gradient on the parametric resonance is investigated in the subcritical and supercritical *** general,the pipe in the supercritical region is more sensitive to the pulsating *** nonlinearity changes from hard to soft,and the non-trivial equilibrium configuration introduces more frequency components to the ***,the increasing Young's modulus gradient improves the critical pulsating flow velocity of the parametric resonance,and further enhances the stability of the *** addition,when the temperature increases along the axial direction,reducing the gradient parameter can enhance the response *** work further complements the theoretical analysis of pipes conveying pulsating fluid.

关键词： pipe conveying fluid axially functionally graded supercritical resonance multi-scale method parametric resonance

Modelling the formation and dissolution behavior of alumina agglomerate in the cryolite

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第3期86卷 211-222页

作者： Jiaqi Wang mao Li Benjun Cheng Hesong Li school of Energy science and Engineering Central South UniversityChangsha410083China

The presence of alumina agglomerates seriously affects the current efficiency of the aluminum electrolysis *** the dynamic dissolution process of agglomerates is essential to improve the current efficiency of aluminum electrolysis.A mathematical model is proposed to describe the different phenomena from the formation until complete dissolution of *** permeation and solidification processes of cryolite,a semi-analytical mathematical model is developed to formulate the formation,melting and dissolution processes of agglomerates,and the time duration for each stage is *** and heat mass transfer of agglomerates are explored based on the packing theory and mechanism of heat mass transfer in wet porous *** approach is applied to investigate the main factors affecting the dissolution stages and porosity of *** results show that the superheat has a great influence on the formation and melting stage,the diameter of agglomerates can reach 14.93 mm for 200 particles *** density decreases with the increase of agglomerated particle number,which varies in the range of 2.27-2.28 g/cm^(3).The average dissolution rate of agglomerates is about 1.83×10^(-5)-2.95×10^(-5) kg/s within the range of alumina concentration in this study.

关键词： Mathematical model Alumina agglomerate Porous media Packing theory Heatand mass transfer

A tribo-chemical view on astringency of plant-based food substances

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第7期12卷 1392-1407页

作者： samuel s.GAMANIEL Paloma s.DUEÑAs ROBLEs Hans TROMP Els H.A.de HOOG sissi de BEER Emile van der HEIDE Laboratory for surface Technology and Tribology Faculty of Engineering TechnologyUniversity of TwenteEnschede 7522 LWthe Netherlands NIZO Food Research B.V. Ede6710 BAthe Netherlands Department of Molecules and Materials MEsA+Institute for Nanotechnology University of TwenteEnschede 7500 AEthe Netherlands

Consumption of plant-based food products having high composition of polyphenols leads to the sensation of *** sliding oral surfaces,friction is an essential property during the oral perception of roughness and dryness which are attributes associated with *** factors including the chemical composition of interacting layers,structure and operation of interfaces have an effect on the astringency development *** manner of interactions occurring at oral interfaces suggest there is a system dependence of astringency and highlights the importance of adopting a tribosystems *** measurement techniques have shown an existing relationship between salivary protein-polyphenol interaction and an astringent ***,the tribo-chemistry involved in this multifaceted sensation remains largely unexplored in a comprehensive *** this review the underlying tribo-chemical processes useful in understanding the mechanism of astringency are highlighted and discussed considering current techniques employed to investigate astringency *** of lubrication on oral surfaces owing to the tribo-chemical interactions involving saliva and astringent plant proteins requires subsequent deformations of oral tissues which are significant enough to induce strains at mechanoreceptor locations,leading to the sensation of *** is proposed that micro-scale contact modelling on the interaction of food particles/aggregates,boundary layers and oral surfaces shows potential in addressing the knowledge gap between tribo-chemical measurement techniques and panel tests,making it possible to attain a predictor for astringency.

关键词： oral lubrication astringency tribo-chemistry tribology

stability analysis and stabilization of semi-Markov jump linear systems with unavailable sojourn-time information

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(Information sciences) 2024年第7期67卷 211-223页

作者： Xiaotai WU Yang TANG shuai mao Ying ZHAO school of Mathematics and Physics Anhui Polytechnic University Key Laboratory of Advanced Control and Optimization for Chemical Processes Ministry of EducationEast China University of Science and Technology

This study addresses the stability and stabilization problems of discrete-time semi-Markov jump linear systems(s-MJLss) with unavailable sojourn-time information. The sojourn-time probability mass functions(s-TPMFs) of discrete-time semi-Markov chains are no longer confined to the geometric distribution, and it is difficult to obtain accurate and comprehensive information for s-TPMFs in practice. This is because s-TPMFs are usually deduced from the statistical characteristics according to the sampled-data, while adequate samples are often costly and time consuming. In this study, when the s-TPMFs for semi-Markov chains are assumed to be unavailable, the σ-error mean square stability is investigated for discrete-time s-MJLss with some widely used assumptions; for semi-Markov chains, only the transition probability matrix of the embedded chain is used. In addition, the existence conditions of the effective controller are provided for closed-loop systems without using the information of s-TPMFs. Numerical examples are presented to illustrate the validity of the obtained theoretical results.

关键词： semi-Markov chain semi-Markov jump linear systems $\sigma$-error mean square stability unavailable sojourn-time information

同方期刊数据库

Three-dimensional reconstruction of precession warhead based on multi-view micro-Doppler analysis

在线全文

学校读者我要写书评

暂无评论

Journal of systems Engineering and Electronics 2024年第3期35卷 541-548页

作者： ZHANG Rongzheng WANG Yong mao Jian school of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China Laboratory of Pinghu Pinghu 314200China

The warhead of a ballistic missile may precess due to lateral moments during release. The resulting micro-Doppler effect is determined by parameters such as the target's motion state and size. A three-dimensional reconstruction method for the precession warhead via the micro-Doppler analysis and inverse Radon transform(IRT) is proposed in this paper. The precession parameters are extracted by the micro-Doppler analysis from three radars, and the IRT is used to estimate the size of targe. The scatterers of the target can be reconstructed based on the above parameters. simulation experimental results illustrate the effectiveness of the proposed method in this paper.

关键词： time-frequency analysis inverse Radon transform(IRT) precession warhead

Modulation of phase boundary and domain structures to engineer strain properties in BNT-based ferroelectrics

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2024年第7期13卷 967-975页

作者： Yule Yang Zhiyong Liu Pengrong Ren Yuqing mao Haijun sun Bingliang Liang Pu mao Kun Guo Bing Xie Longlong shu school of Materials science and Engineering Nanchang Hangkong UniversityNanchang 330063China school of Materials science and Engineering Xi'an University of TechnologyXi’an 710048China school of Aircraft Engineering Nanchang Hangkong UniversityNanchang 330063China school of Physics and Materials science Nanchang UniversityNanchang 330031China

Bismuth sodium titanate(BNT)ceramics exhibit outstanding strain responses but are unfavorable for application in high-sensitivity displacement actuators due to the large negative strain resulting from irreversible changes in their phase transition and domain ***,(1−x)Bi_(0.50)Na_(0.41)K_(0.09)TiO_(3)-xNaNbO_(3)(BNKT−xNN)solid solutions were prepared to improve the strain properties through the strategy of modulating the phase boundary and domain *** introduction of sodium niobate could effectively regulate the relative content of the tetragonal(P4bm)and rhombohedral(R3c)phases in the phase boundary *** ferroelectric-to-relaxor phase transition(TF−R)was reduced,and the ergodic relaxor(ER)state was nurtured at room *** zero-negative strain properties of s=0.41%and d33*=742 pm/V were achieved from the reversible transition between the ER and ferroelectric states under an applied electric field(x=0.04).Additionally,understanding the domain states via piezoelectric force microscopy(PFM)and firstorder reversal curve(FORC)revealed that the superior strain responses originated from the reversible inter-transformation of substable macrodomains and polar nanoregions(PNRs)in the phase *** study provides new insight into the interplay between the evolution of phase boundaries and domain structures and the strain properties of BNT-based ceramics.

关键词： bismuth sodium titanate(BNT) domain structure phase boundary strain response relaxor state