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Graphene Aerogel Composites with Self‑Organized Nanowires‑Packed Honeycomb Structure for Highly Efficient Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第2期17卷 533-547页

作者： Xiao You Huiying Ouyang Ruixiang Deng Qiuqi Zhang Zhenzhong Xing Xiaowu Chen Qingliang Shan Jinshan Yang Shaoming Dong State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Key Laboratory of Inorganic Coating Materials CAS Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Structural Ceramics and Composites Engineering Research Center Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Center of Materials science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049People’s Republic of China School of Physical science and Technology ShanghaiTech UniversityShanghai 201210People’s Republic of China School of Materials science and Engineering Zhejiang Sci-Tech UniversityHangzhou 310018People’s Republic of China University of Chinese Academy of sciences Beijing 100039People’s Republic of China

With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave ***,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss *** macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene *** unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric ***,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 ***,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.

关键词： Hierarchical porous structure Interface High-temperature resistance Graphene aerogel composites Electromagnetic wave absorption

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Cobalamin-dependent radical S-adenosyl-L-methionine protein functions with a partner to successively methylate tricyclic indole alkaloid for chuangxinmycin maturation and derivatization

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science china Chemistry 2025年第1期 308-316页

作者： Sili Wang Jiancheng Huang Yanan Du Wei Huang Yufeng Xue Xiaokun Xu Guannan Zhong Yuanyuan Shi Bin Hong Xiaoying Bian Wen Liu State Key Laboratory of Chemical Biology Shanghai Institute of Organic Chemistry University of Chinese Academy of SciencesChinese Academy of Sciences State Key Laboratory of Microbial Technology Shandong University National Health Commission (NHC) Key Laboratory of Biotechnology for Microbial Drugs Institute of Medicinal BiotechnologyChinese Academy of Medical Science & Peking Union Medical College

Cobalamin(Cbl)-dependent radical S-adenosyl-L-methionine(SAM) proteins constitute the largest collection of the radical SAM superfamily that has hundreds of thousands of individual members. Many of these proteins are involved in the biosynthesis of pharmaceutically important natural products to catalyze chemically demanding reactions. In the biosynthetic pathway of chuangxinmycin(CXM), a unique indole alkaloid antibiotic with potent anti-infective activity, functionalization of the characteristic thiopyrano[4,3,2-cd]indole scaffold by regio-and stereoselective C3-methylation is believed to rely on a Cbl-dependent radical process, which, however, remained to be reconstituted biochemically. We here report the dissection of this enzymatic process, which requires the incorporation of Cxm8, a Cbl-dependent radical SAM protein, with Cxm9, a DUF5825family protein that shares no homology to any proteins of known functions. Cxm8 and Cxm9 function together by forming an unexpected heterodimeric complex that selectively catalyzes C3-methylation of the tricyclic indole-S-hetero ring system in a successive manner, achieving CXM and a recently identified, C3-dimethylated congener. Detailed biochemical characterization,isotope labeling, structural simulation and bioinformatics analysis rationalized the catalysis of the Cxm8/Cxm9 complex and particularly the necessity of the DUF5825 protein for C3-methylase activity. This is the first example that a Cbl-dependent protein acts with a partner to exhibit radical SAM activity.

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Two paths, one goal: mechanism of calcium homeostasis to balance plant growth and immunity

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science china Life sciences 2025年第1期 306-308页

作者： Aziz Ul Ikram Yanping Jing Huan Chen Jian Chen International Genome Center Jiangsu University Joint Center for Single Cell Biology School of Agriculture and BiologyShanghai Jiao Tong University

Calcium(Ca2+) is an essential nutrient and a cellular signal in plants. The level of free Ca2+in the apoplast is ～10,000-fold higher than that in the cytoplasm at the resting state. This large Ca2+level gradient across the membrane between the interior and exterior can cause Ca2+overload and toxicity. Plants have evolved mechanisms to export Ca2+out of the cytoplasm or store it in intracellular organelles, such as endoplasmic reticulum（ER）, mitochondria, and vacuole.

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Photosynthetic reaction pathways of natural and artificial systems

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science china Chemistry 2025年

作者： Shixing Lei Liting Bi Lingxuan Chen Zhanting Li Jia Tian State Key Laboratory of Organometallic Chemistry and Shanghai Hong Kong Joint Laboratory in Chemical Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences

Photosynthesis converts solar energy into chemical energy through highly coordinated photosynthetic *** by natural systems,artificial photosynthesis aims to develop an efficient,sustainable,and cost-effective pathway for solar-tochemical *** review examines natural photosynthetic pathways,including retinal/rhodopsin-,bacteriochlorophyll-,and chlorophyll-based systems,highlighting their key components and ***,we outline reaction pathways in artificial photosynthetic systems constructed via heterogeneous,homogeneous,self-assembly,and semi-artificial strategies,focusing on water splitting,carbon fixation,and nitrogen ***,we offer insights into future directions for artificial photosynthesis,emphasizing the importance of using self-assembly strategies and the potential of using primitive phototrophic microorganisms as models.

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Soliton Compression Due to Cross-Phase-Modulation in the Normal Dispersive Optical Fibers

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Chinese Physics Letters 1995年第8期12卷 493-496页

作者： XU Wencheng LIU Junmin LIAO Changjun LIU Songhao Institute of Quantum Electronics Southern China Normal UniversityGuangzhou 510631

A new method is proposed to compress soliton pulses in the normal dispersive optical fibers through cross-phase-modulation of two *** optimum fiber length for optimum compression is obtained for given values of the pu... 详细信息

关键词： fiber optimum soliton

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Analysis of delay variability at isolated signalized intersections

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Journal of Zhejiang University-science A(Applied Physics & Engineering) 2013年第10期14卷 691-704页

作者： Peng CHEN Huan LIU Hong-sheng QI Fu-jian WANG Department of Civil Engineering Nagoya University Graduate School of Environmental Studies Nagoya University College of Civil Engineering and Architecture Zhejiang University

On urban arterials,travel time variability is largely dependent on the variability in the delays vehicles experience at signalized *** interpretation of delay evolvement at intersections will give a comprehensive insight into arterial travel time variability and provide more possibilities for travel time ***,an analytical model is proposed to study delay variability at isolated,fixed-time controlled *** cumulative curves are utilized to derive average delay(per cycle) formulas by assuming a deterministic overflow ***,an analogy with the Markov chain process is made to clarify the mechanism of stochastic delays and overflow queues at signalized *** was found that,in undersaturated cases,the shape of the delay distribution changes very little over time,whereas for saturated and oversaturated cases the delay distribution is time-dependent and becomes flatter with an increasing number of *** analysis of arrival distributions,e.g.,Poisson and binomial,produces the conclusion that the variability of arrivals has a significant effect on delay estimates in both undersaturated and oversaturated conditions.A larger variance of arrival flow results in a larger variance of delay *** of these analyses can help road authorities to gain insights into arterial travel time variability.

关键词： Delay variability Signalized intersection Cumulative curves Markov chain

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A flexible ultra-broadband multi-layered absorber working at 2 GHz-40 GHz printed by resistive ink

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Chinese Physics B 2024年第2期33卷 329-333页

作者：汪涛闫玉伦陈巩华李迎胡俊毛剑波 School of Microelectronics Hefei University of TechnologyHefei 230601China Special Display and Imaging Technology Innovation Center of Anhui Province Academy of Photoelectric TechnologyHefei University of TechnologyHefei 230027China

A flexible extra broadband metamaterial absorber(MMA)stacked with five layers working at 2 GHz–40 GHz is *** layer is composed of polyvinyl chloride(PVC),polyimide(PI),and a frequency selective surface(FSS),which is printed on PI using conductive *** investigate this absorber,both one-dimensional analogous circuit analysis and three-dimensional full-wave simulation based on a physical model are *** crucial electromagnetic properties,such as absorption,effective impedance,complex permittivity and permeability,electric current distribution and magnetic field distribution at resonant peak points,are studied in *** shows that the working frequency of this absorber covers entire S,C,X,Ku,K and Ka bands with a minimum thickness of 0.098λ_(max)(λ_(max) is the maximum wavelength in the absorption band),and the fractional bandwidth(FBW)reaches 181.1%.Moreover,the reflection coefficient is less than-10 dB at 1.998 GHz–40.056 GHz at normal incidence,and the absorptivity of the plane wave is greater than 80%when the incident angle is smaller than 50°.Furthermore,the proposed absorber is experimentally validated,and the experimental results show good agreement with the simulation results,which demonstrates the potential applicability of this absorber at 2 GHz–40 GHz.

关键词： extra broadband physical model flexible metamaterial absorber multi-layer frequency selective surface

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FREQUENCY DOMAIN CRITERIA FOR ROBUST D-STABILITY OF MIMO SYSTEMS BASED ON LMI METHOD

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Applied Mathematics and Mechanics(English Edition) 2006年第2期27卷 207-213页

作者：李海滨王志珍王龙李兆平李尔效 Department of Mechanics and Engineering science Peking University Beijing 100871 P. R. China P. O. Box 1303-15 Beijing 100073 P. R. China Department of Applied Mathematics Shanghai Normal University Shanghai 200234 P. R. China P. O. Box 1303-15 Beijing 100073 P. R. China P. O. Box 53-601 Lanzhou 730070 P. R. China

The problem of checking robust D-stability of multi-in and multi-out （MIMO） systems was studied. Three system models were introduced, i.e. multilinear polynomial matrix, polytopic polynomial matrix and feedback system model. Furthermore, the convex property of each model with respect to the parametric uncertainties was estabilished respectively. Based on this, sufficient conditions for D-stability were expressed in terms of linear matrix inequalities （LMIs） involving only the convex vertices. Therefore, the robust D-stability was tested by solving an LMI optimal problem.

关键词： polynomial matrix robust D-stability Linear matrix inequalities parametric uncertainty

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Conditions of G^n Continuity Between Surfaces

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science china Mathematics 1994年第3期37卷 365-378页

作者：马利庄彭群生何志钧 State Key Lab.of CAD & CG Institute of Artificial IntelligenceZhejiang UniversityHangzhou 310027PRC State Key Lab.of CAD & CG Institute of Artificial IntelligenceZhejiang UniversityHangzhou 310027PRCeometric continuity between parametric surfaces is an important issue in CAGD.So far rest-arches have been concentrated on it for N-dimensional surfaces whose common boundary is of N-1 dimensions.No results have ever been obtained for the case where the common boundary of the two surfaces is of L dimensions0≤L≤Nor the two adjacent surfaces are of unequal dimensions.In this paperthe conditions of high-order geometric continuity between parametric surfaces are studied for these general cases By analysing the structure of Gn transformationsgeneral solutions as well as an iterative method for determining adjustable functions are proposed.Some equivalent conditions of Gn continuity (nth order geometric continuity) are derived with an emphasis on conditions for triangular and rectangular Bezier surfaces.Since the Gn conditions for polynomial parametric surfaces are expressed in the form of explicit relationship of control points of Bezier surfacesthey are very useful both in theory and application for CAD/CAM and CAGD.FinallyGn conditions between q-dimensional submanifolds of N-dimensional and M-dimensional surfaces are studiedthus a complete theoretical basis is laid for the problem of geometric continuity

Geometric continuity between parametric surfaces is an important issue in *** far rest-arches have been concentrated on it for N-dimensional surfaces whose common boundary is of N-1 *** results have ever been obtained for the case where the common boundary of the two surfaces is of L dimensions,0≤L≤N,or the two adjacent surfaces are of unequal *** this paper,the conditions of high-order geometric continuity between parametric surfaces are studied for these general cases By analysing the structure of Gn transformations,general solutions as well as an iterative method for determining adjustable functions are *** equivalent conditions of Gn continuity (nth order geometric continuity) are derived with an emphasis on conditions for triangular and rectangular Bezier *** the Gn conditions for polynomial parametric surfaces are expressed in the form of explicit relationship of control points of Bezier surfaces,they are very useful both in theory and application for CAD/CAM and ***,Gn conditions between q-dimensional submanifolds of N-dimensional and M-dimensional surfaces are studied,thus a complete theoretical basis is laid for the problem of geometric continuity

关键词： CAGD parametric curves and surfaces nth order geometric continuity

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The Differentiated Effect of Administrative Policy in china’s Housing Market——Based on the Heterogeneous Households Multi-Agent Model

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Journal of Systems science & Complexity 2020年第1期33卷 167-195页

作者： LIU Jiajia DAI Wei LI Xiuting DONG Zhi DONG Jichang School of Economics and Management Beijing University of Chemical TechnologyBeijing 100029China School of Economics and Management University of Chinese Academy of SciencesBeijing 100190China

Since 2010,Chinese government has introduced a series of administrative policies to limit speculation in the housing market to stabilize price fluctuations and keep the housing market in a healthy state of *** order to investigate whether administrative policy can play its due role,this paper constructs a comprehensive bottom-up housing market heterogeneous households multiagent model(HHMAM)to undertake research on the differentiated effect of administrative policy in different *** empirical studies find that:1)Administrative policy that increases interest rates will cause housing prices to continue to decline in the long term,but they will resume a rising trend after reaching the lowest point;2)If the government cancels a property-purchasing limitation,housing prices will continue to rise;and 3)investors tend to invest in 1st-tier cities due to the high demand and greater likelihood of appreciation in these cities.

关键词： Administrative policy consumer behavior heterogeneous households multi-agent model housing prices regional differentiation

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