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Flower-like Au/Ag/TiO2 nanocomposites with enhanced photocatalytic efficiency under visible light irradiation

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Science China Chemistry 2017年第4期60卷 521-527页

作者： Fei Han Xin Mao qing-hua xu Department of Chemistry National University of Singapore Singapore 117543 Singapore National University of Singapore Nanoscience & Nanotechnology Initiative (NUSNNl)-Nanocore Singapore 117576 Singapore National University of Singapore (Suzhou) Research Institute Suzhou 215123 China

Uniform flower-like TiO2 coated Au nanostars and core-shell Au@Ag nanostars with different amounts of Ag coating were prepared through a facile method by hydrolysis of TiF4 under an acidic environment. The photocatalytic capability of these flower-like nanocomposites under visible light irradiation was found to be enhanced by up to 4.7-fold compared to commercial P25 TiO2 nanoparticles. The enhanced photocatalytic activity was ascribed to improved light absorption and hot electron inj ection from the photo-excited Au@Ag core to the TiO2 shell.

关键词： metal nanoparticles TiO2 plasmon resonance nano-flower photocatalysis

Polyfluorene based conjugated polymer nanoparticles for two-photon live cell imaging

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Science China Chemistry 2018年第1期61卷 88-96页

作者： Shuang Li Xiao-Fang Jiang qing-hua xu Institute of Polymer optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 China National University of Singapore (Suzhou) Research Institute Suzhou 215123 China Department of Chemistry National University of Singapore Singapore 117543 Singapore

Two-photon excitation microscopy(2 PEM) has been known as a noninvasive and powerful bio-imaging tool for studying living cells, intact tissues and living animals because of their unique advantages such as localized excitation, deep tissue penetration as well as less photo-damage. However, the major limitations that hinder its practical applications in biological systems are low two-photon absorption cross sections of conventional fluorescence probes. Conjugated polymer nanoparticles(CPNs) consisting of highly fluorescent conjugated polymers are promising fluorescent probes for 2 PEM due to their unique advantages including large two-photon absorption cross sections, high fluorescence quantum yield, good photo-stability and biocompatibility, facile chemical synthesis, tunable optical properties as well as versatile surface modifications. This account summarizes the recent efforts of our group on development of novel polyfluorene based CPNs as 2 PEM contrast agents for live cell imaging.

关键词： conjugated polymers nanoparticles two-photon absorption fluorescence microscopy bio-imaging

On the Fekete and Szego Problem for Starlike Mappings of Order α

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Acta Mathematica Sinica,English Series 2017年第4期33卷 554-564页

作者： qing hua xu Fang FANG Tai Shun LIU College of Mathematics and Information Science JiangXi Normal University Nanchang 330022 P. R. China Department of Mathematics Huzhou University Huzhou 313000 P. R. China

Let Sα*be the familiar class of normalized starlike functions of order α in the unit disk. In this paper, we establish the Fekete and Szeg? inequality for the class Sα*, and then we generalize this result to the un... 详细信息

关键词： Fekete–Szego problem starlike mappings of order α sharp coefficient bound

pH-responsive metal nanoparticles as high contrast theranostic agents for selective imaging and synergistic cancer therapy

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Science China Chemistry 2024年第9期67卷 3063-3070页

作者： Sichao Tian Xiaofeng He Xiao Wu Dongxue Hu qing-hua xu Department of Chemistry National University of SingaporeSingapore 117543Singapore National University of Singapore(Suzhou)Research Institute Suzhou 215123China Institute of Medicinal Plant Development Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China Department of Biological Sciences Faculty of ScienceNational University of SingaporeSingapore 117558Singapore

The low signal-to-noise ratio(S/N)and single functionality of fluorescence imaging agents have limited their practical *** two-photon excitation(2PE)imaging probes are highly desirable in vivo with larger imaging depth,minor autofluorescence background,and less ***,we developed responsive aggregated gold nanoparticles(Au NPs)as high contrast 2PE imaging agents,capable of emitting red fluorescence upon excitation of near-infrared(NIR)laser and possessing a high signal-to-noise ratio(S/N of 2,475).By forming aggregates in situ inside tumor tissue,doxorubicin hydrochloride(DOX)-loaded mix-charged gold nanoparticles(DOX-MC-Au NPs)were utilized to act as selective fluorescence imaging probes and precise therapy *** high-contrast theranostic agents offer a promising potential for precise cancer imaging and therapy,which might open a new venue to multifunctional and noninvasive theranostics.

关键词： metal nanoparticles two-photon excitation high contrast imaging agents fluorescence imaging cancer therapy

Photothermal properties of Cu@polycarbonate composites with strong localized surface plasmon resonances

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Nano Research 2024年第9期17卷 8513-8520页

作者： Fengyi Wang Jiangling He Junshan Hu Zhihui Chen Yumeng Shi qing-hua xu SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of EducationInstitute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China Department of Chemistry National University of Singapore3 Science Drive 3Singapore 117543Singapore College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

Copper is relatively low cost and highly abundant compared with the well-studied noble metals such as gold and ***,the poor plasmonic and high susceptibility towards oxidation limit the study of its optical properties and applications as ***,copper nanoparticles@polycarbonate(Cu@PC)composites were prepared by using a facile one-step solvothermal *** Cu@PC composites have strong localized surface plasmon resonances(LSPR)due to that the PC shell can induce the particles to form many-particles system with different particle numbers,which not only lead to overlap and hybridize of the LSPR modes,but also shift the LSPR away from the interband transitions,and the PC layer also prevents the oxidation of Cu *** photothermal conversion efficiency of Cu@PC composites reaches 41.1%under 808 nm continuous wave(CW)laser irradiation which is higher than previously reported Cu nanomaterials that have been ***,the composites also have high photothermal ***,interfacial evaporator is prepared by assembling the Cu@PC composites on scouring sponge as light absorption layer which has>92.8%absorption in entire solar spectrum *** seawater evaporation rate is 3.177 kg·m^(-2)·h^(-1)with a E_(evaporator)/E_(water)of *** high evaporation rate interfacial evaporator with low cost,simple,and scalable approach shows great application value in the field of photothermal evaporation.

关键词： Cu nanoparticles localized surface plasmon resonances(LSPR) photothermal interfacial evaporation

Lambda polarization at the Electron-ion collider in China

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Nuclear Science and Techniques 2023年第10期34卷 117-125页

作者： Zhaohuizi Ji Xiao-Yan Zhao Ai-Qiang Guo qing-hua xu Jin-Long Zhang Institute of Frontier and Interdisciplinary Science Shandong UniversityQingdao 266237China Institute of Modern Physics of CAS Lanzhou 730000China Southern Center for Nuclear‑Science Theory(SCNT) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China

Lambda polarization can be measured through its self-analyzing weak decay, making it an ideal candidate for studying spin effects in high-energy scattering. In lepton-nucleon deep inelastic scattering(DIS), Lambda polarization measurements can probe polarized parton distribution functions(PDFs) and polarized fragmentation functions(FFs). One of the most promising facilities for high-energy nuclear physics research is the proposed Electron-ion collider in China(EicC). As a next-generation facility, EicC is set to advance our understanding of nuclear physics to new heights. In this article, we study the Lambda production in electron-proton collisions at the EicC energy, in particular the reconstruction of Lambda based on the performance of the designed EicC detector. In addition, taking spontaneous transverse polarization as an example, we provide a theoretical prediction with a statistical projection based on one month of EicC data, offering valuable insights into future research prospects.

关键词： Electron-ion collider in China Lambda polarization Polarizing fragmentation functions Nucleon structure

First synthesis of (±)-cedarmycin B

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Chinese Chemical Letters 2009年第9期20卷 1023-1024页

作者： Hai Shen Yang Xiao Xiao Qiao qing Cui Xiao hua xu State Key Laboratory of Elemento-Organic Chemistry Nankai University Tianjin 300071 China

The synthesis of racemic cedannycin B, an antibiotic from Streptomyces sp. TP-A0456 was achieved firstly from γ- butyrolactone. The key step was a Barbier-type addition of 3-bromomethyl-5H-furan-2-one to formaldehyde mediated by zinc, which afforded the sole γ-addition product 4-hydroxymethyl-3-methylene-dihydrofuran-2-one. The final compound was confirmed by 1H NMR, 13C NMR and HRMS. 2009 Xiao hua xu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： Cedarrnycin B Antibiotic Streptomyces sp. Barbier reaction 3-Bromomethyl-5H-furan-2-one

A“Transformers”-like nanochain for precise navigation and efficient cancer treatment

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Aggregate

Aggregate 2024年第4期5卷 426-433页

作者： Sichao Tian Qian Zeng Zhanglu Hu Weidong Zhang Zhuo Ao Dong Han qing-hua xu Department of Chemistry National University of SingaporeSingaporeSingapore National University of Singapore(Suzhou)Research institute SuzhouChina Institute of Medicinal Plant Development Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina CAS Center for Excellence in Nanoscience National Center for Nanoscience and TechnologyBeijingChina School of Pharmacy Second Military Medical UniversityShanghaiChina School of Future Technology University of Chinese Academy of SciencesBeijingChina College of Life Sciences Beijing University of Chinese MedicineBeijingChina

Integrated multimodal imaging in theranostics nanomaterials offers extensive prospects for precise and noninvasive cancer *** controlling the structural evolution of plasmonic nanoparticles is crucial in the development of pho-tothermal ***,previous successes have been limited to static assemblies and single-component ***,an activatable plasmonic theranostics system utilizing self-assembled 1D silver-coated gold nanochains(1D nanochains)is pre-sented for precise tumor diagnosis and effective *** absorbance of the adaptable core–shell chain structure can shift from visible to near-infrared(NIR)regions due to the fusion between nearby Au@Ag nanoparticles induced by ele-vated H2O2 levels in the tumor microenvironment(TME),resulting in the creation of a novel 3D aggregates with strong NIR *** a high photothermal conversion efﬁciency of 60.2%at 808 nm,nanochains utilizing the TME-activated characteristics show remarkable qualities for photoacoustic imaging and signiﬁ-cantly limit tumor growth in *** study may pave the way for precise tumor diagnosis and treatment through customizable,optically tunable adaptive plasmonic nanostructures.

关键词： adjustable core–shell structure aggregation-induced emission metal nanochains photoacoustic imaging stimuli responsive therapy

Monolayer Graphene as a Saturable Absorber in a Mode-Locked Laser

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Nano Research 2011年第3期4卷 297-307页

作者： Qiaoliang Bao Han Zhang Zhenhua Ni Yu Wang Lakshminarayana Polavarapu Zexiang Shen qing-hua xu Dingyuan Tang Kian Ping Loh Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore School of Electrical and Electronic Engineering Nanyang Technological University Singapore 639798 Singapore School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore These authors contributed equally to this work.

We demonstrate that the intrinsic properties of monolayer graphene allow it to act as a more effective saturable absorber for mode-locking fiber lasers when compared to multilayer graphene. The absorption of monolayer graphene can be saturated at lower excitation intensity compared to multilayer graphene, graphene with wrinkle-like defects, or functionalized graphene. Monolayer graphene has a remarkably large modulation depth of 65.9%, whereas the modulation depth of multilayer graphene is greatly reduced due to nonsaturable absorption and scattering loss. Picosecond ultrafast laser pulses （1.23 ps） can be generated using monolayer graphene as a saturable absorber. Due to the ultrafast relaxation time, larger modulation depth and lower scattering loss of monolayer graphene, it performs better than multilayer graphene in terms of pulse shaping ability, pulse stability, and output energy.

关键词： Graphene saturable absorber laser carrier dynamics ultrafast photonics