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Kumada chain-growth polycondensation as a universal method for synthesis of well-defined conjugated polymers

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Science china Chemistry 2010年第8期53卷 1620-1633页

作者： GENG YanHou1.huang Li1.2.WU ShuPeng1.2.& WANG FoSong1.1.tate Key Laboratory of Polymer Physics and Chemistry Changchun {1. of applied Chemistry,chinese academy of sciences,Changchun 1.002.,{12. 2.raduate University of chinese academy of sciences,beijing 1.0049,{12. State Key Laboratory of Polymer Physics and Chemistry Changchun institute of {1. Chemistry Chinese Academy of Sciences Changchun China Graduate University of chinese academy of sciences Beijing China

Kumada chain-growth polycondensation (KCGP) is a novel method for the synthesis of well-defined conjugated *** the Ni-catalyst can transfer in an intramolecular process to the propagating chain end,the polymerization follows chain-growth *** this newly developed method,various conjugated polymers,such as polythiophenes,poly(p-phenylene) (PPP),polypyrrole (PPy),and polyfluorene with controlled molecular weights and relatively narrow polydispersities (PDIs),have been ***,the polymerizations for poly(3-alkylthiophene)s (P3ATs),PPP,and PPy exhibited quasi-living characteristics,which allows preparing polymer brushes,fully-conjugated block copolymers,and macroinitiators and macro-reactants for the synthesis of rod-coil block *** the current review,the progress in this new area is summarized.

关键词： chain growth polycondensation conjugated polymers Kumada reaction block copolymers polymer brush

Inverse design of nonlinear phononic crystal configurations based on multi-label classification learning neural networks

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chinese Physics B 2024年第10期33卷 295-301页

作者： Kunqi huang Yiran Lin Yun Lai {1. Liu Key Laboratory of Modern Acoustics Institute of AcousticsNanjing UniversityNanjing 210093China School of Physics Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China

Phononic crystals,as artificial composite materials,have sparked significant interest due to their novel characteristics that emerge upon the introduction of *** these properties,second-harmonic features exhibit potential applications in acoustic frequency conversion,non-reciprocal wave propagation,and non-destructive *** manipulating the harmonic band structure presents a major challenge in the design of nonlinear phononic *** design approaches based on parameter adjustments to meet specific application requirements are inefficient and often yield suboptimal ***,this paper develops a design methodology using Softmax logistic regression and multi-label classification learning to inversely design the material distribution of nonlinear phononic crystals by exploiting information from harmonic transmission *** results demonstrate that the neural network-based inverse design method can effectively tailor nonlinear phononic crystals with desired *** work establishes a mapping relationship between the band structure and the material distribution within phononic crystals,providing valuable insights into the inverse design of metamaterials.

关键词： multi-label classification learning nonlinear phononic crystals inverse design

Economical cascadic multigrid method (ECMG)

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Science china Mathematics 2007年第12期50卷 1765-1780页

作者： Zhong-ci SHI~1 Xue-jun XU~(1+) Yun-qing huang~2.~1 LSEC,institute of Computational Mathematics,{2. of Mathematics and Systems Science,chinese {2. of sciences,beijing 100080,china ~2.Hunan Key Laboratory for Computation and Simulation in Science and Engineering,institute for Computational and applied Mathematics,Xiangtan University,Xiangtan 411105,china LSEC Institute of Computational Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China Hunan Key Laboratory for Computation and Simulation in Science and Engineering Institute for Computational and Applied Mathematics Xiangtan University Xiangtan China

In this paper, an economical cascadic multigrid method is proposed. Compared with the usual cascadic multigrid method developed by Bornemann and Deuflhard, the new one requires less iterations on each level, especially on the coarser grids. Many operations can be saved in the new cascadic multigrid algorithms. The main ingredient is the control of the iteration numbers on the each level to preserve the accuracy without over iterations. The theoretical justification is based on the observations that the error reduction rate of an iteration scheme in terms of the smoothing property is no longer accurate while the iteration number is big enough. A new formulae of the error reduction rate is employed in our new algorithm. Numerical experiments are reported to support our theory.

关键词： economical cascadic multigrid method (ECMG), cascadic multigrid method (CMG)

BRST quantization and canonical Ward identity of the supersymmetric electromagnetic interaction system

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Science china(Physics,Mechanics & Astronomy) 2007年第3期50卷 339-347页

作者： huang YongChang1,3,4, JIANG YunGuo1 & LI XinGuo2.3 1 institute of Theoretical Physics, College of {2. sciences, beijing University of Technology, beijing 10002., china 2.institute of Modern Physics, chinese academy of sciences, Lanzhou 730000, china 3 Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Collisions, chinese academy of sciences, Lanzhou 730000, china 4 china Center of Advanced Science and Technology (World Laboratory), beijing 100080, china institute of Theoretical Physics College of Applied Sciences Beijing University of Technology Beijing China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Collisions Chinese Academy of Sciences Lanzhou China china Center of Advanced Science and Technology (World Laboratory) Beijing China institute of Modern Physics Chinese Academy of Sciences Lanzhou China

According to the method of path integral quantization for the canonical constrained system in Becchi-Rouet-Stora-Tyutin scheme, the supersymmetric electromagnetic interaction system was quantized. Both the Hamiltonian of the supersymmetric electromagnetic interaction system in phase space and the quantization procedure were simplified. The BRST generator was constructed, and the BRST transforma- tions of supersymmetric fields were gotten; the effective action was calculated, and the generating functional for the Green function was achieved; also, the gauge generator was constructed, and the gauge transformation of the system was ob- tained. Finally, the Ward-Takahashi identities based on the canonical Noether theorem were calculated, and two relations between proper vertices and propaga- tors were obtained.

关键词： supersymmetric electromagnetic interaction BRST quantization Ward identity

Greenhouse Gas Emissions from Northeast china Rice Fields in Fallow Season

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Pedosphere 2007年第5期17卷 630-638页

作者： LIANG Wei SHI Yi ZHANG Hua YUE Jin huang Guo-Hong institute of {1. Ecology Chinese Academy of Sciences Shenyang 110016 （China） Graduate School of the chinese academy of sciences Beijing 10005g （China） College of Resources and Environment Huazhong Agricultural University Wuhan 430070 （China）

CH4, N2. and CO2.emissions from northeast chinese rice fields were measured in the fallow season （November to March） to investigate the effects of freezing-thawing on the emissions. Both CH4 emission from and atmospheric CH4 oxidation by the soil occurred, but the flux was small. During the fallow season, rice fields acted as a minor source of atmospheric CH4, which accounted for about 1. of the CH4 emission during the rice growing period. The field was also a substantial source of atmospheric N2., which ranged between 40 to 77 mg m-{1. eu=counted for 40%-50% of the annual N2. emission. The largest N2. flux was observed in the thawing period during the fallow season. Laboratory incubation tests showed that the largest N2. flux came from the release of N2. trapped in frozen soil. Tillage and rice straw application （either mulched on the soil surface or incorporated in the soil） stimulated the CH4 and CO2.emissions during the fallow season, but only straw application stimulated N2. emission substantially.

关键词： CH4 CO2 freezing-thawing N2. rice field

The asymptotic stability of multistep multiderivative methods for systems of delay differential equations

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Communications in Nonlinear Science and Numerical Simulation 2000年第1期5卷 24-26页

作者： Chengming huang and Qianshun CHANG {1. of {2. Mathematics, chinese academy of sciences, P. O. Box 2.34, beijing 100080, china institute of {1. Mathematics Chinese Academy of Sciences P. O. Box 2734 Beijing 100080 China

This paper deals with the asymptotic stability of multistep multiderivative methods for systems of delay differential equations. In particular, it is shown that A-stability of multistep multiderivative methods for ord... 详细信息

关键词： delay differential equation stability multistep multiderivative methods

Surface effects of monolayer-protected gold nanoparticles on the redox reactions between ferricyanide and thiosulfate

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Science china Chemistry 2005年第5期48卷 424-430页

作者： LI Di1. SUN Chunyan1. {2. Yunjie1. LI Jinghong1.2.& CHEN Shaowei3 1. State Key Laboratory of Electroanalytical Chemistry, Changchun {1. of applied Chemistry, chinese academy of sciences, Changchun 1.002., china 2. Department of Chemistry, Tsinghua University, beijing 1.0084, china 3. Department of Chemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA State Key Laboratory of Electroanalytical Chemistry Changchun institute of {1. Chemistry Chinese Academy of Sciences Changchun China Department of Chemistry Tsinghua University Beijing China Department of Chemistry University of California Santa Cruz Santa Cruz USA

Electron transfer through the self-assembled monolayers (SAMs) on gold nanopar-ticles is investigated by using the monolayer protected gold nanoclusters (MPCs) as elec-tron-transfer mediators. 3-Mercaptopropionic acid (MPA) and 1.-meraptoundecanoic acid (MUA) MPCs were employed to catalyze the redox reaction between potassium ferricyanide and sodium thiosulfate. The catalytic mechanism was proposed that the MPCs act as diffusing elec-tron-mediators and electron transfers to and from the MPCs surface. Therefore the electron transfer rate through the capping layers would be proportional to the MPCs catalyzed reaction rate, which was monitored by the UV absorbance of ferricyanide. The calculated apparent rate constant was orders of magnitude smaller than that of the maximum of tunneling current, which was attributed to the splited energy level of the nanoscale particles.

关键词： electron transfer, three-dimensional self-assembled monolayers, redox reaction, electron transfer mediator, surface effect.

Spectroscopic evidence for triplet excitation energy transfer among carotenoids in the LH2.complex from photosynthetic bacterium Rhodopseudomonas palustris

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Science china Chemistry 2004年第1期47卷 80-90页

作者： FENG Juan, WANG Qian, ZHANG Xujia, huang Youguo, Al Xicheng, ZHANG Xingkang & ZHANG JianpingState Key Laboratory for Structural Chemistry of Unstable and Stable Species, {1. of Chemistry,{2., beijing 100080, china National Laboratory of Biomacromolecules, {1. of Biophysics,{2., beijing 1.01.1. china State Key Laboratory for Structural Chemistry of Unstable and Stable Species institute of Chemistry Chinese Academy of Sciences Beijing China National Laboratory of Biomacromolecules institute of Biophysics Chinese Academy of Sciences Beijing China

The LH2.complex from Rhodopsudomonas (Rps.) palustris is unique in the heterogeneous carotenoid compositions. The dynamics of triplet excited state Carotenoids (3Car* has been investigated by means of sub-microsecond time-resolved absorption spectroscopy both at physiological temperature (2.5 K) and at cryogenic temperature (77K). Broad and asymmetric T n ←T 1.transient absorption was observed at room temperature following the photo-excitation of Car at 532.nm, which suggests the contribution from various carotenoid compositions having different numbers of conjugated C=C double bonds (Nc=c). The triplet absorption bands of different carotenoids, which superimposed at room temperature, could be clearly distinguished upon decreasing the temperature down to 77 K. At room temperature the shorter-wavelength side of the main Tn04T1.absorption band decayed rapidly to reach a spectral equilibration with a characteristic time constant of ∽1.μs, the same spectral dynamics, however, was not observed at 77 K. The aforementioned spectral dynamics can be explained in terms of the triplet-excitation transfer among heterogeneous carotenoid compositions. Global spectral analysis was applied to the time-resolved spectra at room temperature, which revealed two spectral components peaked at 545 and 565 nm, and assignable to the Tn04 T1.absorption of Cars with Nc=c=1. and Nc=c=1., respectively. Surprisingly, the decay time constant of a shorter-conjugated Car, i.e. 0.72.?s (aerobic) and 1.36 ?s (anaerobic), is smaller than that of a longer-conjugated Car, i.e. 2.1. us (aerobic) and 3.75 ?s (anaerobic), which is contradictory to the general rule of carotenoids and relative polyenes. The results are explained in terms of triplet-excitation transfer among different types of Cars. It is postulated that two Cars with different conjugation lengths coexist in an α, β-subunit in the LH2.complex.

关键词： purple photosynthetic bacteria, carotenoid, excited-state, time-resolved spectroscopy.

Understanding the Low Predictability of the 2.1./1. El Niño Event Based on a Deep Learning Model

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Advances in Atmospheric sciences 2024年第7期41卷 1313-1325页

作者： Tingyu WANG Ping huang Xianke {1. Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China National Space Science Center Chinese Academy of SciencesBeijing 100190China State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China College of Plant Science and Technology Huazhong Agricultural UniversityWuhan 430070China

The 2.1./1. El Niño event ranks among the top three of the last 1.0 years in terms of intensity,but most dynamical models had a relatively low prediction skill for this event before the summer ***,the attribution of this particular event can help us to understand the cause of super El Niño–Southern Oscillation events and how to forecast them *** present study applies attribute methods based on a deep learning model to study the key factors related to the formation of this event.A deep learning model is trained using historical simulations from 2.0}CMIP6 models to predict the Niño-3.4 *** integrated gradient method is then used to identify the key signals in the North Pacific that determine the evolution of the Niño-3.4 *** crucial signals are then masked in the initial conditions to verify their roles in the *** addition to confirming the key signals inducing the super El Niño event revealed in previous attribution studies,we identify the combined contribution of the tropical North Atlantic and the South Pacific oceans to the evolution and intensity of this event,emphasizing the crucial role of the interactions among them and the North *** approach is also applied to other El Niño events,revealing several new precursor *** study suggests that the deep learning method is useful in attributing the key factors inducing extreme tropical climate events.

关键词： ENSO attribution deep learning ENSO prediction extreme El Niño