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Polarity,intramolecular charge transfer,and hydrogen bond comediated solvent effects on the optical properties of graphene quantum dots

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Nano Research 2023年第1期16卷 45-52页

作者： Yalei Hu Christof Neumann Lena Scholtz Andrey Turchanin Ute Resch-Genger Siegfried Eigler Institute of Chemistry and Biochemistry Freie Universität BerlinTakustraße 314195 BerlinGermany Institute of Physical Chemistry and Abbe Center of Photonics Friedrich Schiller University JenaLessingstraße 1007743 JenaGermany Federal Institute for Materials Research and Testing(BAM) Division BiophotonicsRichard Willstätter Straße 1112489 BerlinGermany

Graphene quantum dots(GQDs)have attracted increasing attention due to their favorable optical properties and have been widely used,e.g.,in the biomedical ***,the properties related to the chemical structure of GQDs,resulting in solventdependent optical properties,still remain ***,we present the synthesis of long-wavelength emitting GQDs with a size of about 3.6 nm via a solvothermal method using oxo-functionalized graphene(oxo-G)and p-phenylenediamine as precursors and their structural and surface chemical analysis by transmission electron and atomic force microscopy(TEM;AFM)as well as Fourier-transform infrared,Raman,and X-ray photoelectron spectroscopy(FTIR;Raman;XPS).Subsequently,the influence of solvent polarity and proticity on the optical properties of the as-prepared GQDs bearing–OH,–NH_(2),–COOH and pyridine surface groups was *** on the results of the absorption and fluorescence(FL)studies,a possible luminescence mechanism is *** observed solvent-induced changes in the spectral position of the FL maximum,FL quantum yield,and FL decay kinetics in protic and aprotic solvents of low and high polarity are ascribed to a combination of polarity effects,intramolecular charge transfer(ICT)processes,and hydrogen ***,the potential of GQDs for the optical sensing of trace amount of water was *** results of our systematic spectroscopic study will promote the rational design of GQDs and shed more light on the FL mechanism of carbon-based fluorescent nanomaterials.

关键词： graphene quantum dots(GQDs) polarity intramolecular charge transfer(ICT) hydrogen bond optical properties

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Computational screening of materials with extreme gap deformation potentials

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npj Computational Materials 2022年第1期8卷 1482-1491页

作者： Pedro Borlido Jonathan Schmidt Hai-Chen Wang Silvana Botti Miguel A.L.Marques Institut für Festkörpertheorie und-optik Friedrich-Schiller-Universität Jena and European Theoretical Spectroscopy FacilityMax-Wien-Platz 107743JenaGermany CFisUC Department of PhysicsUniversity of CoimbraRua Larga3004-516CoimbraPortugal Institut für Physik Martin-Luther-Universität Halle-WittenbergD-06099HalleGermany

In this work,we present a large-scale study of gap deformation potentials based on density-functional theory calculations for over 5000 *** expected,in most cases the band gap decreases for increasing volume with deformation potentials that can reach values of almost−15 *** find,however,also a sizeable number of materials with positive deformation *** members of this group are halide perovskites,known for their applications in *** then focus on understanding the physical reasons for so different values of the deformation potentials by investigating the correlations between this property and a large number of other material and compositional *** also train explainable machine learning models as well as graph convolutional networks to predict deformation potentials and establish simple rules to understand predicted ***,we analyze in more detail a series of materials that have record positive and negative deformation potentials.

关键词： deformation properties. extreme

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The Role of Enthalpy of Reaction in the Process of Global Warming: What Can We Learn from Basic Thermodynamics*

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Advances in Chemical Engineering and Science 2021年第1期11卷 77-90页

作者： Wolfram Vogelsberger Department of Chemistry Institute of Physical Chemistry Friedrich-Schiller-Universit&#228 t jena Jena Germany

An increase of carbon dioxide content accompanied by an increase of the temperature is observed in the atmosphere during the last 200 years. This behaviour can be explained by examination of correlations between tree generally accepted data sets of the recent past, world population, carbon dioxide content in the atmosphere, and rise of global temperature as function of time. No return to climate situations from hundred thousand of years before present is necessary. The world climate is a dynamic equilibrium between all energy generating processes on earth, especially sun energy, and the radiation of energy into space. Since approx. 200 years the dynamic equilibrium is changed additionally by means of fossil energy carriers, whose depots were put on in passed geological epochs, a climatic disturbance was produced. It is shown that the consumption of energy per year by the mankind can warm up the atmosphere by about one degree. This quantity cannot be neglected in climatic calculations;therefore it is the cause of mankind made warming of the atmosphere. The qualitative analyses presented here have shown that the use of so-called renewable energy sources does not necessarily lead to the avoidance of global warming. It can be expected that some techniques will have no or even small effect. Especially the model calculations to the operation of wind turbines and its influence on the temperature of the atmosphere show that it is difficult to estimate their influence and cannot be foreknown.

关键词： Reaction Enthalpy Global Temperature Fossil Energy Carriers Climatic Disturbance

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Diode-pumped, electro-optically Q-switched, cryogenic Tm:YAG laser operating at 1.88 μm

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High Power Laser Science and Engineering 2021年第1期9卷 107-112页

作者： J?rg K?rner Venkatesan Jambunathan Fangxin Yue Jürgen Reiter Ondrej Slezák Petr Navrátil Samuel Paul David Antonio Lucianetti Joachim Hein Tomá? Mocek Malte C.Kaluza HiLASE Centre Institute of Physics of the Czech Academy of Sciences Institute of Optics and Quantum Electronics Friedrich Schiller University Jena Helmholz Institute jena Hi LASE Centre Institute of Physics of the Czech Academy of Sciences

We present a diode-pumped, electro-optically Q-switched Tm:YAG laser with a cryogenically cooled laser crystal at120 K. Output pulses of up to 2.55 mJ and 650 ns duration were demonstrated in an actively Q-switched configuration with a repetition rate of 1 Hz. By using cavity dumping the pulse duration was shortened to 18 ns with only a slightly lower output energy of 2.22 mJ. Furthermore, using a simplified rate equation model, we discuss design constraints on the pump fluence in a pulse pump approach for Tm:YAG to maximize the energy storage capability at a given pump power.

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Kinematic evolution of fold-and-thrust belts in the Yubei-Tangbei area: Implications for tectonic events in the southern Tarim Basin

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Geoscience Frontiers 2021年第6期12卷 46-65页

作者： Yiqiong Zhang Dengfa He Bin Wu Huahua Gao friedrich-schiller-Universität jena Burgweg 11Jena 07749Germany China university of Geosciences(Beijing) Beijing 100083China Research Institute of Petroleum Exploration and Development PetroChinaBeijing 100083China CNOOC Research Institute Ltd. Beijing 100028China China National Oil and Gas Exploration and Development Corporation Beijing 100034China

The Yubei-Tangbei area in the southern Tarim Basin is one of the best-preserved Early Paleozoic northeast-southwest trending fold-and-thrust belts within this *** area is crucial for the exploration of primary hydrocarbon reservoirs in northwestern *** this study,we constructed the structural geometric morphology of the Yubei-Tangbei area using geophysical logs,drilling,and recent two-and three-dimensional(2-D and 3-D)seismic *** Early Paleozoic fault-propagation folds,the Tangnan triangle zone,fault-detachment folds,and trishear fault-propagation folds developed with the detachment of the Middle Cambrian gypsum–salt *** to a detailed chronostratigraphic framework,the growth strata in the Upper Ordovician–Lower Silurian layer formed by onlapping the back limb of the asymmetric fault-propagation folds,which therefore defines the timing of *** changes in kink band hinges and amplitudes in the Permian–Carboniferous and Cenozoic folding strata suggest that the evolution of the fold-and-thrust belts followed a sequential evolution process rather than a simultaneous *** the pre-existing Precambrian basement structure,the Yubei-Tangbei fold-and-thrust belts can be divided into four tectonic evolution stages:Late Cambrian,Late Ordovician to Early Carboniferous,Carboniferous to Permian,and *** northwestern-verging Cherchen Fault is part of the piedmont fold-and-thrust system of the southern Tarim foreland *** interpreted its strata as a breakthrough trishear fault-propagation fold that developed in three phases:Mid–Late Ordovician,Silurian to Middle Devonian,and Triassic to *** tectonic events are responses of the Altyn-Tagh and Kunlun collisional orogenic belts and the Indian-Eurasian *** inherited deformation and structural modification in the southern Tarim Basin may be an indicator of the growth and evolution of peripheral orogens.

关键词： Southern Tarim Basin Seismic profile Growth strata Kunlun orogeny Altyn-Tagh orogeny Cherchen Fault

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Watt-scale super-octave mid-infrared intrapulse difference frequency generation

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Light(Science & Applications) 2018年第1期7卷 124-131页

作者： Christian Gaida Martin Gebhardt Tobias Heuermann Fabian Stutzki Cesar Jauregui Jose Antonio-Lopez Axel Schulzgen Rodrigo Amezcua-Correa Andreas Tunnermann Ioachim Pupeza Jens Limpert Institute of Applied Physics Abbe Center of PhotonicsFriedrich-Schiller-Universitat JenaAlbert-Einstein-Str.1507745 JenaGermany Helmholtz-Institute jena Frobelstieg 307743 JenaGermany Fraunhofer Institute for Applied Optics and Precision Engineering Albert-Einstein-Str.707745 JenaGermany CREOL College of Optics and PhotonicsUniversity of Central FloridaOrlandoFL 32816USA Max-Planck-Institute of Quantum Optics Hans-Kopfermann-Str.185748 GarchingGermany

The development of high-power,broadband sources of coherent mid-infrared radiation is currently the subject of intense research that is driven by a substantial number of existing and continuously emerging applications in medical diagnostics,spectroscopy,microscopy,and fundamental *** of the major,long-standing challenges in improving the performance of these applications has been the construction of compact,broadband mid-infrared radiation sources,which unify the properties of high brightness and spatial and temporal *** to the lack of such radiation sources,several emerging applications can be addressed only with infrared(IR)-beamlines in largescale synchrotron facilities,which are limited regarding user access and only partially fulfill these ***,we present a table-top,broadband,coherent mid-infrared light source that provides brightness at an unprecedented level that supersedes that of synchrotrons in the wavelength range between 3.7 and 18μm by several orders of *** result is enabled by a high-power,few-cycle Tm-doped fiber laser system,which is employed as a pump at 1.9μm wavelength for intrapulse difference frequency generation(IPDFG).IPDFG intrinsically ensures the formation of carrierenvelope-phase stable pulses,which provide ideal prerequisites for state-of-the-art spectroscopy and microscopy.

关键词： pump coherent difference

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Ionic liquids on uncharged and charged surfaces: In situ microstructures and nanofriction

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Friction 2022年第11期10卷 1893-1912页

作者： Rong AN Yudi WEI Xiuhua QIU Zhongyang DAI Muqiu WU Enrico GNECCO Faiz Ullah SHAH Wenling ZHANG Herbert Gleiter Institute of Nanoscience School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China High Performance Computing Department National Supercomputing Center in ShenzhenShenzhen 518055China Otto Schott Institute of Materials Research(OSIM) Friedrich Schiller University JenaJena 07743Germany Chemistry of Interfaces LuleåUniversity of TechnologyLulea 97187Sweden School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

In situ changes in the nanofriction and microstructures of ionic liquids(ILs)on uncharged and charged surfaces have been investigated using colloid probe atomic force microscopy(AFM)and molecular dynamic(MD)*** representative ILs,[BMIM][BF_(4)](BB)and[BMIM][PF_(6)](BP),containing a common cation,were selected for this *** torsional resonance frequency was captured simultaneously when the nanoscale friction force was measured at a specified normal load;and it was regarded as a measure of the contact stiffness,reflecting in situ changes in the IL microstructures.A higher nanoscale friction force was observed on uncharged mica and highly oriented pyrolytic graphite(HOPG)surfaces when the normal load increased;additionally,a higher torsional resonance frequency was detected,revealing a higher contact stiffness and a more ordered IL *** nanofriction of ILs increased at charged HOPG surfaces as the bias voltage varied from 0 to 8 V or from 0 to−8 *** simultaneously recorded torsional resonance frequency in the ILs increased with the positive or negative bias voltage,implying a stiffer IL layer and possibly more ordered ILs under these *** simulation reveals that the[BMIM]+imidazolium ring lies parallel to the uncharged surfaces preferentially,resulting in a compact and ordered IL *** parallel“sleeping”structure is more pronounced with the surface charging of either sign,indicating more ordered ILs,thereby substantiating the AFM-detected stiffer IL layering on the charged *** in situ observations of the changes in nanofriction and microstructures near the uncharged and charged surfaces may facilitate the development of IL-based applications,such as lubrication and electrochemical energy storage devices,including supercapacitors and batteries.

关键词： microstructure friction contact stiffness charged surfaces ionic liquids(ILs) molecular simulation

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Chemosensitivity Testing of Circulating Epithelial Tumor Cells (CETC) in Vitro: Correlation to in VivoSensitivity and Clinical Outcome

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Journal of Cancer Therapy 2013年第2期4卷 597-605页

作者： Nadine Rudiger Ernst-Ludwig Stein Erika Schill Gabriele Spitz Carola Rabenstein Martina Stauch Matthias Rengsberger Ingo B. Runnebaum Ulrich Pachmann Katharina Pachmann Clinic for Internal Medicine II University Hospital Friedrich Schiller University Jena Germany Onkologische Schwerpunktpraxis Kronach Germany Transfusionsmedizinisches Zentrum Bayreuth Germany Women’s Hospital University Hospital Friedrich Schiller University Jena Germany

Background: Chemotherapy is a mainstay of tumor therapy, however, it is predominantly applied according to empirically developed recommendations derived from statistical relapse rates occurring years after the treatment in the adjuvant situation and from progression-free interval data in the metastatic situation, without any possibility of individually determining the efficacy in the adjuvant situation and with loss of time and quality of life in the metastatic situation if the drugs chosen are not effective. Here, we present a method to determine the efficiency of chemotherapeutic drugs using tumor cells circulating in blood as the part of the tumor actually available in the patient’s body for chemosensitivity testing. Methodology/Principal Findings: After only red blood cell lysis, omitting any enrichment (analogous to other blood cell enumeration methods, including rare CD34 cells), the white cells comprising the circulating epithelial tumor cells (CETC) are exposed to the drugs in question in different concentrations and for different periods of time. Staining with a fluorescence-labeled anti-epithelial antibody detects both vital and dying tumor cells, distinguishing vital from dying cells through membrane permeability and nuclear staining with propidium iodide. Increasing percentages of dying tumor cells are observed dependent on time and concentration. The sensitivity can vary during therapy and was correlated with decrease or increase in CETC and clinical outcome. Conclusions/Significance: Thus, we are able to show that chemosensitivity testing of circulating tumor cells provides real-time information about the sensitivity of the tumor present in the patient, even at different times during therapy, and correlates with treatment success.

关键词： Circulating Epithelial Tumor Cells Chemosensitivity Testing Breast Cancer Ovarian Cancer

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A mathematical model for the dynamics and MCMC analysis of tomato bacterial wilt disease

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International Journal of Biomathematics 2018年第1期11卷 1-22页

作者： Flavia Remo Livingstone S. Luboobi Isambi Sailon Mabalawata Betty K. Nannyonga Institut fiir Mathematik Friedrich Schiller University Jena Ernst-Abbe-Platz 2 Jena 07743 Germany Department of Mathematics Makerere University P. O. Box 7062 Kampala Uganda African Institute of Mathematical Sciences (AIMS) Tanzania P. O. Box 176 Bagamoyo -- Coastal Region Tanzania

In this paper, we formulate and analyze a mathematical model to investigate the trans- mission dynamics of tomato bacterial wilt disease （TBWD） in Mukono district, Uganda. We derive the basic reproduction number R0 and prove the existence of a disease- free equilibrium point which is globally stable if R0 〈 1 and an endemic equilibrium which exists if R0 〉 1. Model parameters are estimated using the Markov Chain Monte Carlo （MCMC） methods and robustness tested. The model parameters were observed to be identifiable. Numerical simulations show that soil solarization and sensitization of

关键词：数学模型西红柿动力学 MCMC 疾病枯萎细菌模型参数

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In-SituXAFS Characterization of PtPd Nanoparticles Synthesized by Galvanic Replacement

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Advances in Nanoparticles 2017年第2期6卷 75-91页

作者： Simon Tymen Andreas C. Scheinost Christian Friebe Ulrich S. Schubert Institute of Organic and Macromolecular Chemistry (IOMC) Friedrich-Schiller University Jena Germany The Rossendorf Beamline at the European Synchroton European Synchrotron Radiation Facility (ESRF) Grenoble France and Molecular Structure Division Institute of Radiochemistry Forschungszentrum Dresden-Rossendorf (FZD) Dresden Germany Center for Energy and Environmental Chemistry jena (CEEC jena) Friedrich-Schiller University Jena Germany jena Center for Soft Matter (JCSM) Friedrich-Schiller University Jena Germany

Platinum-palladium nanoparticles are synthesized and characterized with regard to their application in fuel cells due to their high (electro) catalytic activity. Different preparation times are applied leading to different structures, from Pd cubic to core-shell PtPd concave, and different chemical compositions. The resulting particles are studied via Transmission Electron Microscopy (TEM) and in-situ X-ray absorption fine structure (XAFS) measurements. The latter allows the investigation of the oxygen reduction reaction following the variations with varying applied potentials by analysis using the Iterative Transformation Factor Analysis (ITFA) and the creation of a two-component system that consists of metallic Pt-Pd and the related oxide. With the used model, the different concentrations of the oxide are linked to the consecutive chemical steps of the oxygen reduction reaction. Finally, the catalytic activity of the particles is determined via linear scanning voltammetry and reveals a dependence on the shape and the composition of the particles.

关键词： Platinum Palladium Nanoparticles Oxygen Reduction Reaction In-Situ XAFS ITFA

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