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Positive-instantaneous frequency and approximation

Frontiers of Mathematics in China 2022年第3期17卷 337-371页

作者： Tao qian Macao Center for Mathematical Science Macao University of Science and TechnologyMacaoChina

Positive-instantaneous frequency representation for transient signals has always been a great concern due to its theoretical and practical importance,although the involved concept itself is *** desire and practice of uniqueness of such frequency representation(decomposition)raise the related topics in *** approximately the last two decades there has formulated a signal decomposition and reconstruction method rooted in harmonic and complex analysis giving rise to the desired signal *** method decomposes any signal into a few basic signals that possess positive instantaneous *** theory has profound relations to classical mathematics and can be generalized to signals defined in higher dimensional manifolds with vector and matrix values,and in particular,promotes kernel approximation for multi-variate *** article mainly serves as a *** also gives two important technical proofs of which one for a general convergence result(Theorem 3.4),and the other for necessity of multiple kernel(Lemma 3.7).Expositorily,for a given real-valued signal f one can associate it with a Hardy space function F whose real part coincides with *** function F has the form F=f+iHf,where H stands for the Hilbert transformation of the *** develop fast converging expansions of F in orthogonal terms of the form F=∑k=1^(∞)c_(k)B_(k),where B_(k)'s are also Hardy space functions but with the additional properties B_(k)(t)=ρ_(k)(t)e^(iθ_(k)(t)),ρk≥0,θ′_(k)(t)≥0,*** original real-valued function f is accordingly expanded f=∑k=1^(∞)ρ_(k)(t)cosθ_(k)(t)which,besides the properties ofρ_(k)andθ_(k)given above,also satisfies H(ρ_(k)cosθ_(k))(t)ρ_(k)(t)sinρ_(k)(t).Real-valued functions f(t)=ρ(t)cosθ(t)that satisfy the conditionρ≥0,θ′(t)≥0,H(ρcosθ)(t)=ρ(t)sinθ(t)are called *** f is a mono-component,then the phase derivativeθ′(t)is defined to be instantaneous frequency of *** above described positive-instantaneou

关键词： Möbius transform blaschke product mono-component hilbert transform hardy space inner and outer functions adaptive fourier decomposition rational orthogonal system nevanlinna factorization beurling-lax theorem reproducing kernel hilbert space several complex variables Clifford alge-bra pre-orthogonal AFD

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Patterns of phylogenetic relatedness of non-native plants across the introduction-naturalization-invasion continuum in China

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Plant Diversity 2023年第2期45卷 169-176页

作者： Hong qian CAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China Research and Collections Center Illinois State Museum1011 East Ash StreetSpringfieldIL 62703USA

Human activities have caused the exchange of species among different parts of the *** introduced species become naturalized and invasive,they may cause great negative impacts on the environment and human societies,and pose significant threats to biodiversity and ecosystem *** on phylogenetic relatedness between native and non-native species and among non-native species at different stages of species invasion may help for better understanding the drivers of species ***,I analyze a comprehensive data set including both native and non-native angiosperm species in China to determine phylogenetic relatedness of introduced species across a full invasion continuum(from introduction through naturalization to invasion).This study found that(1) introduced plants are a phylogenetically clustered subset of overall(*** plus non-native) angiosperm flora,(2) naturalized plants are a phylogenetically clustered subset of introduced plants,and(3) invasive plants are a phylogenetically clustered subset of naturalized *** patterns hold regardless of spatial scales examined(*** versus provincial scale) and whether basal-or tip-weighted metric of phylogenetic relatedness is *** findings are consistent with Darwin's preadaptation hypothesis.

关键词： Angiosperm Community assembly Darwin's preadaptation hypothesis Exotic species Introduced species Phylogenetic dispersion

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Intercontinental comparison of phylogenetic relatedness in introduced plants at the transition from naturalization to invasion:A case study on the floras of South Africa and China

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Plant Diversity 2023年第4期45卷 363-368页

作者： Hong qian Research and Collections Center Illinois State Museum1011 East Ash StreetSpringfieldIL 62703USA

Invasive species may pose significant threats to biodiversity and ecosystem structure and *** number of introduced species that have become invasive is substantial and is rapidly *** potentially invasive species and preventing their expansion are of critical importance in invasion *** relatedness between invasive and native species has been used in predicting invasion *** studies on the phylogenetic relatedness of plants at the transition from naturalization to invasion have shown mixed results,which may be because different methods were used in different ***,I use the same method to analyze two comprehensive data sets from South Africa and China,using two phylogenetic metrics reflecting deep and shallow evolutionary histories,to address the question whether the probability of becoming invasive is higher for naturalized species distantly related to the native *** study suggests that the probability of becoming invasive is higher for naturalized species closely related to the native *** finding of my study is consistent with Darwin's preadaptation hypothesis.

关键词： Angiosperms Exotic species Introduced species Invasive species Naturalized species Phylogenetic relatedness

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Macrophage based drug delivery:Key challenges and strategies

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Bioactive Materials 2024年第8期38卷 55-72页

作者： qian Guo Zhong-Ming qian Laboratory of Drug Delivery School of MedicineShanghai University99 Shangda RoadShanghai200444China Institute of Translational and Precision Medicine Nantong University19 Qi Xiu RoadNantongJiangsu226019China National Clinical Research Center for Aging and Medicine of Huashan Hospital Fudan UniversityShanghai201203China

As a natural immune cell and antigen presenting cell,macrophages have been studied and engineered to treat human *** are well-suited for use as drug carriers because of their biological characteristics,such as excellent biocompatibility,long circulation,intrinsic inflammatory homing and ***,macrophages’uniquely high plasticity and easy re-education polarization facilitates their use as part of efficacious therapeutics for the treatment of inflammatory diseases or *** recent studies have demonstrated promising advances in macrophage-based drug delivery,several challenges currently hinder further improvement of therapeutic effect and clinical *** article focuses on the main challenges of utilizing macrophage-based drug delivery,from the selection of macrophage sources,drug loading,and maintenance of macrophage phenotypes,to drug migration and release at target *** addition,corresponding strategies and insights related to these challenges are ***,we also provide perspective on shortcomings on the road to clinical translation and production.

关键词： Macrophages Cell therapy Drug delivery Nano-or micro-particles Cell polarization

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Maximizing the Minimum and Maximum Forcing Numbers of Perfect Matchings of Graphs

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Acta Mathematica Sinica,English Series 2023年第7期39卷 1289-1304页

作者： qian qian LIU He Ping ZHANG School of Mathematics and Statistics Lanzhou UniversityLanzhou 730000China

Let G be a simple graph with 2n vertices and a perfect *** forcing number f(G,M) of a perfect matching M of G is the smallest cardinality of a subset of M that is contained in no other perfect matching of *** all perfect matchings M of G,the minimum and maximum values of f(G,M) are called the minimum and maximum forcing numbers of G,denoted by f(G) and F(G),*** f(G)≤F(G) ≤*** and Chen(2011) proposed an open problem:how to characterize the graphs G with f(G)=*** they showed that for a bipartite graph G,f(G)=n-1 if and only if G is complete bipartite graph K_(n,n).In this paper,we completely solve the problem of Che and Chen,and show that f(G)=n-1 if and only if G is a complete multipartite graph or a graph obtained from complete bipartite graph K_(n,n) by adding arbitrary edges in one partite *** all graphs G with F(G)=n-1,we prove that the forcing spectrum of each such graph G forms an integer interval by matching 2-switches and the minimum forcing numbers of all such graphs G form an integer interval from [n/2] to n-1.

关键词： Perfect matching minimum forcing number maximum forcing number forcing spectrum complete multipartite graph

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基于多维邻近性的药学领域科技创新主导力扩散仿真研究

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现代情报 2025年第1期45卷 60-80页

作者：贺超城黄茜徐雨舒吴江武汉大学信息管理学院湖北武汉430072

[目的/意义]科技创新主导力与创新团队的产出绩效息息相关,在日益庞杂的科技创新合作中至关重要。然而现有科技创新主导力的研究大多集中在定性讨论方面,本文从定量角度深入探讨科技创新主导力网络的演化机制,有助于进一步促进科技创新... 详细信息

[目的/意义]科技创新主导力与创新团队的产出绩效息息相关,在日益庞杂的科技创新合作中至关重要。然而现有科技创新主导力的研究大多集中在定性讨论方面,本文从定量角度深入探讨科技创新主导力网络的演化机制,有助于进一步促进科技创新合作。[方法/过程]本文以药学领域的数据驱动,设定创新主体的搜索规则、主导规则、创新规则,以平均科技创新增益及其扩散速率为评价指标来衡量科技创新主导力的扩散效果,模拟科技创新主导力的扩散过程,并进一步探究多维邻近性与科技创新主导力扩散的动态关系。[结果/结论]结果显示,多维邻近性对科技创新主导力扩散具有重要影响,且不同邻近性在网络演化的不同阶段发挥着不同的作用。本文全面细致地刻画了多维邻近性在科技创新主导力网络演化的不同阶段所发挥的具体作用,进而为机构/企业和创新个体的发展提供参考。

关键词：科技创新主导力扩散机制多维邻近性仿真模拟科研合作网络

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Friction-Induced Nanofabrication: A Review

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Chinese Journal of Mechanical Engineering 2021年第2期34卷 26-51页

作者： Bingjun yu Linmao qian Tribology Research Institute State Key Laboratory of Traction PowerSouthwest Jiaotong UniversityChengdu 610031China

As the bridge between basic principles and applications of nanotechnology,nanofabrication methods play significant role in supporting the development of nanoscale science and engineering,which is changing and improving the production and lifestyle of the *** lithography and other alternative technologies,such as nanoimprinting,electron beam lithography,focused ion beam cutting,and scanning probe lithography,have brought great progress of semiconductor industry,IC manufacturing and micro/nanoelectromechanical system(MEMS/NEMS)***,there remains a lot of challenges,relating to the resolution,cost,speed,and so on,in realizing high-quality products with further development of *** of the existing techniques can satisfy all the needs in nanoscience and nanotechnology at the same time,and it is essential to explore new nanofabrication *** a newly developed scanning probe microscope(SPM)-based lithography,friction-induced nanofabrication provides opportunities for maskless,flexible,low-damage,low-cost and environment-friendly processing on a wide variety of materials,including silicon,quartz,glass surfaces,and so *** has been proved that this fabrication route provides with a broad application prospect in the fabrication of nanoimprint templates,microfluidic devices,and micro/nano optical *** paper hereby involved the principals and operations of friction-induced nanofabrication,including friction-induced selective etching,and the applications were reviewed as well for looking ahead at opportunities and challenges with nanotechnology *** present review will not only enrich the knowledge in nanotribology,but also plays a positive role in promoting SPM-based nanofabrication.

关键词： Scanning probe microscope Tip-based lithography Friction-induced nanofabrication Friction-induced selective etching

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PHOTOCATALyTIC PERFORMANCE OF PLASMA SPRAyED TiO_2-ZnFe_2O_4 COATINGS

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 363-368页

作者： y.Zeng J.T.Liu W.J.qian J.H.Gao ShanghaiInstituteofCeramics TheChineseAcademyofSciencesShanghai200050China

A novel TiO2-ZnFe2O4 coating is prepared by plasma spraying. The effects of spra ying parameters and the composition of powders on the microstructure, surface mo rphology and photo-absorption of plasma sprayed coatings are studied. The photoc atalytic efficiency of the as-sprayed coatings is evaluated through the photo mi neralization of methylene blue. It was found that TiO2 coatings can decompose me thylene blue under the illumination of ultraviolet rays, and the degrading effic iency is improved with an increase in the content of FeTiO3 in the coatings. How ever, the presence of large amount of ZnFe2O4 compound will substantially lower the photocatalytic efficiency of the TiO2-ZnFe2O4 coatings for the unfavorable p hoto-excited electron-hole transfer process.

关键词： plasma spraying photocatalytic activity TiO2 ZnFe2O4

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Advances and challenges in developing cocatalysts for photocatalytic conversion of carbon dioxide to fuels

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Nano Research 2022年第12期15卷 10090-10109页

作者： qian Wang Zhenhua Pan Graduate School of Engineering Nagoya UniversityFuro-choChikusa-kuNagoya464-8603Japan Institute for Advanced Research Nagoya UniversityFuro-choChikusa-kuNagoya464-8601Japan Department of Applied Chemistry Faculty of Science and TechnologyChuo University1-13-27 KasugaBunkyoTokyo112-8551Japan

The global adoption of efficient sustainable energy sources is a crucial step toward meeting energy demands while achieving carbon emission reduction *** energy has become a clean and cost-competitive alternative to traditional fossil fuels,but the intermittent nature of sunlight results in challenges associated with energy storage and *** carbon dioxide reduction intends to mimic natural photosynthesis for utilizing sunlight to chemically convert water and CO_(2) into *** this process,the solar energy is captured and stored in fuels,so-called solar fuels,for widespread on-demand *** solar fuel production systems are multi-component,comprising light-harvesting(photosensitizer)and catalytic(cocatalyst)*** are indispensable for photocatalytic CO_(2) reduction systems,which promote charge carrier separation and transport,reduce the reaction activation energy,and alter the reaction route,thereby enhancing the activity and selectivity of the photocatalytic *** review presents a comprehensive summary of the recent advancements in cocatalysts for photocatalytic CO_(2) reduction reaction(CO_(2)RR),with the purpose of providing new insights and guidance to the field with regard to research directions and best *** summarize how various cocatalysts including inorganic nanoparticles,metal complexes,enzymes,and bacteria can be combined with semiconductor photosensitizer for light-driven photocatalytic CO_(2)***-by-side comparisons reveal the strengths and limitations of each kind of cocatalysts and how lessons extracted from studying natural photosynthetic systems can be applied to investigations of artificial photosynthesis,presenting an outlook discussing possible future concepts for a more effective photocatalytic CO_(2) reduction process.

关键词： photocatalysis cocatalyst carbon dioxide reduction artificial photosynthesis solar fuel production

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Liquid metal printing opening the way for energy conservation in semiconductor manufacturing industry

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Frontiers in Energy 2022年第4期16卷 542-547页

作者： qian LI Jing LIU Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing 100190China Department of Biomedical Engineering School of MedicineTsinghua UniversityBeijing 100084China

For nearly a century,semiconductor has kept playing an extremely important role in promoting the advancement of modern science,technology and society,owing to its performance advantages and industry-driven ***,when the time comes to this day and age,the semiconductor area,which is entering into its 3rd generation era,even develops much rapidly than ever ***,the semiconductor industry is mainly driven by three generations of *** first generation,represented by silicon(Si)and germanium(Ge),began from the *** second generation,represented by gallium arsenide(GaAs)and indium phosphide(InP),emerged from the *** third generation,focusing on those of gallium nitride(GaN)and silicon carbide(SiC),dated back to the late 20th *** semiconductor industry,as the most capital,human and technology-intensive manufacturing area,is often faced with such a tough challenge:before the production begins,water and electricity have to be in *** to the present,nearly all the classical semiconductor growth technologies such as molecular beam epitaxy(MBE),pulsed laser deposition(PLD),metal-organic chemical vapor deposition(MOCVD),and atomic layer deposition(ALD)*** been relying heavily on high temperature processing and perfect vacuum conditions(Figs.1(a)and 1(b)),which were basically subjected to large power stability.

关键词： printing tough carbide

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