Magnetohydrodynamic stagnation point on a Casson nanofluid flow over a radially stretching sheet

• Ganji Narender,
• Kamatam Govardhan and
• Gobburu Sreedhar Sarma

Beilstein J. Nanotechnol. 2020, 11, 1303–1315, doi:10.3762/bjnano.11.114

• manufacturing [3], food industry [4], and in many other fields. In this regard, fluid dynamics is essential for regulating thermal energy through the usage of different fluids with good thermophysical properties. Research efforts have been focused on developing strategies to enhance thermal processes. For

• dynamics. Over the past few decades, these studies have become even more important due to its applicability in manufacturing industries. The refrigeration of electronic instruments with a fan, cooling of atomic receptacles during an emergency power outage, and solar receivers for storage of thermal energy

Growth of a self-assembled monolayer decoupled from the substrate: nucleation on-command using buffer layers

• Robby Reynaerts,
• Kunal S. Mali and
• Steven De Feyter

Beilstein J. Nanotechnol. 2020, 11, 1291–1302, doi:10.3762/bjnano.11.113

• polymorph A was observed at the bare HOPG–1-phenyloctane interface. For n-C50, the chosen optimal concentration was 0.01 mM, because at this concentration we observed reasonably high-average domain size and relatively low dynamics within the n-C50 monolayer. Figure 4a–c shows a representative large scale

• not always aligned as is the case in Figure 5a–c. For n-C50, the chosen optimal concentration was 1.0 × 10−4 M, because at this concentration we observed reasonably high average domain size and relatively low dynamics within the n-C50 monolayer. Lowering the concentration of BA-OC14 further (range

Structure and electrochemical performance of electrospun-ordered porous carbon/graphene composite nanofibers

• Yi Wang,
• Yanhua Song,
• Chengwei Ye and
• Lan Xu

Beilstein J. Nanotechnol. 2020, 11, 1280–1290, doi:10.3762/bjnano.11.112

• that OPCGCNFs can be used as electrodes due to their advantages, such as fast ion dynamics, high electron conductivity and low electron transport impedance. This may be due to the following two factors: (i) The ordered fiber structure of the OPCGCNF electrode allows for the ions to move in an orderly

Role of redox-active axial ligands of metal porphyrins adsorbed at solid–liquid interfaces in a liquid-STM setup

• Thomas Habets,
• Sylvia Speller and
• Johannes A. A. W. Elemans

Beilstein J. Nanotechnol. 2020, 11, 1264–1271, doi:10.3762/bjnano.11.110

• , such dynamics are likely. In the proposed redox reactions, the chloride ligands, which are axially coordinated to the manganese centers, play an essential role in generating the observed currents. First, they dissociate when the manganese center is reduced. We propose that the ions are subsequently

Influence of the magnetic nanoparticle coating on the magnetic relaxation time

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2020, 11, 1207–1216, doi:10.3762/bjnano.11.105

• Langevin dynamics method was applied based on the effective Verlet-type algorithm. The Néel magnetic relaxation time was obtained via the Coffey method in an oblique magnetic field, adapted to the local magnetic field on a nanoparticle. Keywords: colloidal system; effective Verlet-type algorithm; magnetic

• relaxation time; nanoparticle coating; numerical simulation; stochastic Langevin dynamics method; superparamagnetic nanoparticles; Introduction One of the most important biomedical applications of colloidal magnetic nanoparticle systems is magnetic hyperthermia applied as an alternative for cancer treatment

• distribution of the grain size. Each nanoparticle is composed of a magnetic core and a nonmagnetic surface layer of stabilizing surfactant. The system temperature is considered to be constant. To simulate the self-organization of the colloidal magnetic nanoparticles we used the Langevin dynamics stochastic

Thermophoretic tweezers for single nanoparticle manipulation

• Jošt Stergar and
• Natan Osterman

Beilstein J. Nanotechnol. 2020, 11, 1126–1133, doi:10.3762/bjnano.11.97

• with sizes of 1 μm and 200 nm in an aqueous medium. We model the effect with an overdamped Langevin dynamics simulation to obtain quantitative predictions. Since the feedback control algorithm can be easily modified, the resulting particle trapping potential can be thus arbitrarily shaped. We show this

• dynamics simulation of a spherical particle in water. The laser heating was modeled as an instantly imposed Gaussian-shaped temperature field, which changes its center position according to the feedback rule. To keep the model as simple as possible, the heat capacities of the substrate and the liquid, as

Vibration analysis and pull-in instability behavior in a multiwalled piezoelectric nanosensor with fluid flow conveyance

• Sayyid H. Hashemi Kachapi

Beilstein J. Nanotechnol. 2020, 11, 1072–1081, doi:10.3762/bjnano.11.92

• and the study of vibration behavior are essential. Additionally, it is important that the size-dependent parameters for the dynamics analysis and mathematical modeling of these nanostructures be contained in the theoretical models. For this reason, surface/interface elasticity, which was addressed by

Microwave photon detection by an Al Josephson junction

• Leonid S. Revin,
• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Anton A. Yablokov,
• Igor V. Rakut,
• Victor O. Zbrozhek and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2020, 11, 960–965, doi:10.3762/bjnano.11.80

• ]. For the lower-frequency range, a new class of single-microwave-photon detectors is needed. With regard to this, a current-biased Josephson junction (JJ) is of particular interest for applications as a threshold detector since its phase dynamics is altered even by a weak probe field. Rich dynamics of

• washboard potential in the framework of the resistively and capacitively shunted junction (RCSJ) model for the dynamics of the Josephson phase [29][30]. The tilt of the washboard potential is controlled by the bias current I and is defined as EJ(I/IC), where IC is the critical current and EJ = ℏIC/2e. The

• current distribution [21][31]. For underdamped junctions (α ≪ 1), the width of the switching current distributions monotonically decreases with decreasing temperature. In the case of moderately damped junctions (α > 0.2), the switching dynamics changes due to phase diffusion, i.e., the width of the

Measurement of electrostatic tip–sample interactions by time-domain Kelvin probe force microscopy

• Christian Ritz,
• Tino Wagner and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2020, 11, 911–921, doi:10.3762/bjnano.11.76

• simplicity, this publication focusses on the implementation of the most basic case with three states, where only the quadratic influence on the Kelvin parabola is considered. The model of the measurement system, which is used by the state observer, has to include the dynamics of the detection system. If a

• spectral density (PSD) of the thermal noise can be calculated as For detection-noise-limited measurements, an additional state has to be introduced to keep track of the dynamics of the apparent noise. The approximation in Equation 17 contains the system output matrix . It depends on the current tip–sample

• measurement and by recording the frequency-shift signal and the applied bias voltage, the surface potential image can be reconstructed by the state observer. This is a very convenient way of performing KFM measurements by postprocessing. Furthermore, the dynamics of the controller can be studied and tested

Three-dimensional solvation structure of ethanol on carbonate minerals

• Hagen Söngen,
• Ygor Morais Jaques,
• Peter Spijker,
• Christoph Marutschke,
• Stefanie Klassen,
• Ilka Hermes,
• Ralf Bechstein,
• Lidija Zivanovic,
• John Tracey,
• Adam S. Foster and
• Angelika Kühnle

Beilstein J. Nanotechnol. 2020, 11, 891–898, doi:10.3762/bjnano.11.74

• molecular dynamics (MD) simulations. Within a single AFM data set we are able to resolve both the first laterally ordered solvation layer of ethanol on the calcite surface as well as the following solvation layers that show no lateral order. Our experimental results are in excellent agreement with MD

• has been investigated theoretically by using both density functional theory (DFT) [12][13] and molecular dynamics (MD) simulations [14][15][16][17]. It has been found that ethanol molecules strongly bind towards calcite (10.4) terraces – even stronger than water [12][14][16][17]. Ethanol molecules

• Information File 1, where we also discuss the robustness and reproducibility of the AFM results. Molecular dynamics simulations We employed molecular dynamics simulations to model both calcite and magnesite with their (10.4) surface exposed as a nine layer crystal with three surface unit cells in the

Simulations of the 2D self-assembly of tripod-shaped building blocks

• Łukasz Baran,
• Wojciech Rżysko and
• Edyta Słyk

Beilstein J. Nanotechnol. 2020, 11, 884–890, doi:10.3762/bjnano.11.73

• Lukasz Baran Wojciech Rzysko Edyta Slyk Department for Theoretical Chemistry, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Sklodowska University in Lublin, Poland. 10.3762/bjnano.11.73 Abstract We introduce a molecular dynamics (MD) coarse-grained model for the description of

• can lead to valuable conclusions, which can be further explored and proved by experimental studies. To date, there are two main approaches that can complement the results obtained in experiments. The first one involves the use of all-atom simulations by molecular dynamics (MD) [27][28][29][30]. Even

• ” active sites, respectively. In a) we can see that the arms are marked as A, B, and C. e) Parameters of the molecular dynamics model. Part of the configurations for a) NT111 at T* = 0.58, b) NL111 at T* = 0.54, and c) WT111 at T* = 0.58, all with ρ* = 0.2. d) Corresponding Monte Carlo simulation on a

Light–matter interactions in two-dimensional layered WSe₂ for gauging evolution of phonon dynamics

• Avra S. Bandyopadhyay,
• Chandan Biswas and
• Anupama B. Kaul

Beilstein J. Nanotechnol. 2020, 11, 782–797, doi:10.3762/bjnano.11.63

• of Electrical and Computer Engineering, University of Texas, El Paso, TX 79968, United States 10.3762/bjnano.11.63 Abstract Phonon dynamics is explored in mechanically exfoliated two-dimensional WSe2 using temperature-dependent and laser-power-dependent Raman and photoluminescence (PL) spectroscopy

• oscillator model to explain the damping mechanism in WSe2. From this it was determined that the damping coefficient increases with the number of layers. The work reported here sheds fundamental insights into the evolution of phonon dynamics in WSe2 and should help pave the way for designing high-performance

• , grown from bottom-up processes akin to graphene. While graphene is comprised of a single element on the periodic table, i.e., carbon, TMDCs are binary compounds which makes their lattice dynamics more complex compared to multilayer (ML) graphene [6]. The symmetry, force constants, and frequency

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

• energy in each group (±20 meV) was attributed to variations of the strain in the h-BN matrix, as well as photo-conversion to a dark state that may be responsible for the blinking. Only 5% of the emitters were photostable. The photo-dynamics indicates the presence of a metastable state (3-level system

• at 675 nm, and emitters with ZPLs of 760 nm were found with a much shorter lifetime and a saturation count rate in the 200 kcts/s. The photo-dynamics of these emitters indicate the presence of a multilevel system with three metastable states with long decay rates of 480 ns, 5 µs and 31 ms. Blinking

• were studied. Here the correlations between material structural features and the location of SPEs from bulk down to the monolayer was studied at room temperature. Chemical etching and ion irradiation are used to generate the SPEs in h-BN various materials. Their photo-dynamics analysis reveals

Quantitative determination of the interaction potential between two surfaces using frequency-modulated atomic force microscopy

• Nicholas Chan,
• Carrie Lin,
• Tevis Jacobs,
• Robert W. Carpick and
• Philip Egberts

Beilstein J. Nanotechnol. 2020, 11, 729–739, doi:10.3762/bjnano.11.60

• mechanics models [22][23][24][25] to allow better visualization of surface interactions. While useful insights can be obtained using fully atomistic simulations, such as molecular dynamics simulations or density functional theory, these techniques are impractical for describing larger contacts with a large

Stochastic excitation for high-resolution atomic force acoustic microscopy imaging: a system theory approach

• Edgar Cruz Valeriano,
• José Juan Gervacio Arciniega,
• Christian Iván Enriquez Flores,
• Susana Meraz Dávila,
• Joel Moreno Palmerin,
• Martín Adelaido Hernández Landaverde,
• Yuri Lizbeth Chipatecua Godoy,
• Aime Margarita Gutiérrez Peralta,
• Rafael Ramírez Bon and
• José Martín Yañez Limón

Beilstein J. Nanotechnol. 2020, 11, 703–716, doi:10.3762/bjnano.11.58

• spring constant of 0.2 N/m were used. All experiments were carried out in dry air at a temperature of 21.0 ± 0.1 °C and a relative humidity of (2 ± 1)%. It is very important to define the appropriate signal to perturb the system. This allows for gathering sufficient information about the system dynamics

• . For this work, a stochastic signal is used for the tip–sample excitation because it can extract all the system dynamics, i.e., persistent excitation in the system theory field [23][24]. A FFT of the deflection signal from the photodiodes is computed by the NI PXIe-1073 device. One FFT is carried out

• frequency resolution. Theoretically, a white-noise signal features an infinitely flat bandwidth, which is impossible to generate [35][49]. Fortunately, it can be generated in approximation using a waveform function generator. This makes the white-noise signal an ideal tool to extract all system dynamics

A novel dry-blending method to reduce the coefficient of thermal expansion of polymer templates for OTFT electrodes

• Xiangdong Ye,
• Bo Tian,
• Yuxuan Guo,
• Fan Fan and
• Anjiang Cai

Beilstein J. Nanotechnol. 2020, 11, 671–677, doi:10.3762/bjnano.11.53

• the influence of fullerene (C60) on the CTE of Araldite LY 5052/Aradur HY 5052 cross-linked epoxy resin by molecular dynamics simulations. The CTE was minimized by adding a maximum of 15.9 wt % fullerene to the LY/HY/C60 epoxy system. Liu et al. [14] selected MCM-41 mesoporous silica nanoparticles

Comparison of fresh and aged lithium iron phosphate cathodes using a tailored electrochemical strain microscopy technique

• Matthias Simolka,
• Hanno Kaess and
• Kaspar Andreas Friedrich

Beilstein J. Nanotechnol. 2020, 11, 583–596, doi:10.3762/bjnano.11.46

• , Institute of Building Energetics, Thermal Engineering and Energy Storage (IGTE), Pfaffenwaldring 31, 70569 Stuttgart, Germany 10.3762/bjnano.11.46 Abstract Electrochemical strain microscopy (ESM) is a powerful atomic force microscopy (AFM) mode for the investigation of ion dynamics and activities in energy

• storage materials. Here we compare the changes in commercial LiFePO4 cathodes due to ageing and its influence on the measured ESM signal. Additionally, the ESM signal dynamics are analysed to generate characteristic time constants of the diffusion process, induced by a dc-voltage pulse, which changes the

• iron dissolution the lower ESM signal is a direct consequence. It is noted that this is probable, as Fe-dissolution has been reported as the prominent degradation mechanism of LFP [9][72][73]. The dynamics of the relaxation process after the dc-voltage pulse are further analysed in Figure 7 and Figure

Interfacial charge transfer processes in 2D and 3D semiconducting hybrid perovskites: azobenzene as photoswitchable ligand

• Nicole Fillafer,
• Tobias Seewald,
• Lukas Schmidt-Mende and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2020, 11, 466–479, doi:10.3762/bjnano.11.38

• . Therefore, decreased radiative recombination can be observed and increased photoswitching occurs. Time-dependent fluorescence measurements reveal the distance-dependent energy transfer dynamics. We observe much shorter lifetimes for small insulating spacers (AzoC1 and AzoC2) than for longer spacers (AzoOC4

• and AzoOC12), which can be seen in Figure 6B. As many other charge-carrier dynamics beside the radiative recombination, such as photorecycling and surface defects, affect the PL no (bi)exponential fit could be found [53][54]. Thus, the recorded measurements are discussed qualitatively. A small spacing

• perovskite surface (AzoC1, AzoC2) leads to a rapid injection of excited electrons into the chromophore. A larger spacing (AzoOC12) suppresses the transfer and extended lifetimes are observed. Conclusion We have investigated the interfacial dynamics between 2D and 3D hybrid perovskite phases and novel

Current measurements in the intermittent-contact mode of atomic force microscopy using the Fourier method: a feasibility analysis

• Berkin Uluutku and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 453–465, doi:10.3762/bjnano.11.37

• stem from the dynamics and mechanics of an intermittent-contact operation. Besides the fact that electrical contacts would be intermittent, the nature of the contact would also be time-dependent within the contact time. This is because the indentation is constantly varying. Furthermore, the

Nanoparticles based on the zwitterionic pillar[5]arene and Ag⁺: synthesis, self-assembly and cytotoxicity in the human lung cancer cell line A549

• Dmitriy N. Shurpik,
• Denis A. Sevastyanov,
• Pavel V. Zelenikhin,
• Pavel L. Padnya,
• Vladimir G. Evtugyn,
• Yuriy N. Osin and
• Ivan I. Stoikov

Beilstein J. Nanotechnol. 2020, 11, 421–431, doi:10.3762/bjnano.11.33

• nuclear Overhauser effects (NOE) between spatially close protons gives useful information about the dynamics and averaged relative inter/intramolecular proton distances of these particles within 0.4 nm in solution [37][38][39]. Н8/Н1, Н8/Н2, Н6/Н2, Н8/Н3 cross peaks are observed in the 2D 1H,1H-ROESY NMR

High dynamic resistance elements based on a Josephson junction array

• Konstantin Yu. Arutyunov and
• Janne S. Lehtinen

Beilstein J. Nanotechnol. 2020, 11, 417–420, doi:10.3762/bjnano.11.32

• ), including superconducting systems based on the Josephson effect. It has been shown that physics behind a Josephson junction (JJ) is dual to a quantum phase-slip junction (QPSJ) [3], whereby the corresponding QPSJ-based qbit operation has also been demonstrated [4]. At the same time, the quantum dynamics of

• necessary, a small magnetic field, up to 0.05 T, was applied using small superconducting coils wound directly on the sample holder cap. Results and Discussion The ultimate goal of this work is to study the quantum dynamics of the QPSJ, a system dual to JJ [3], including the observation of Coulomb blockade

Interactions at the cell membrane and pathways of internalization of nano-sized materials for nanomedicine

• Valentina Francia,
• Daphne Montizaan and
• Anna Salvati

Beilstein J. Nanotechnol. 2020, 11, 338–353, doi:10.3762/bjnano.11.25

• [160][161], or by inducing bending of the plasma membrane [162][163], as already observed with certain viruses [164]. These changes in membrane dynamics might as well be a trigger for the endocytosis of nanoparticles via alternative mechanisms, which are not yet fully characterized. Extracting

Implementation of data-cube pump–probe KPFM on organic solar cells

• Benjamin Grévin,
• Olivier Bardagot and
• Renaud Demadrille

Beilstein J. Nanotechnol. 2020, 11, 323–337, doi:10.3762/bjnano.11.24

• ); organic photovoltaics; photocarrier dynamics; pump–probe configuration; time-resolved measurements; Introduction Many emerging photovoltaic technologies rely on the use of thin film materials displaying structural and/or chemical heterogeneities at the μm or nm scale. This is the case for solution

• the photocharging time is not negligible compared to the light pulse duration. In this case, numerical simulations are necessary to properly analyze the spectroscopic SP(fmod) curves [18]. When investigating organic donor–acceptor (D–A) blends, both capacitive effects and photocharging dynamics shall

• global electrostatic landscape probed by KPFM in the dark state [20]. The photocharging dynamics can be understood as follows. After exciton splitting and dissociation of the charge transfer states at the D–A interfaces, the photogenerated carriers experience a drift-diffusion limited by the carrier

Understanding nanoparticle flow with a new in vitro experimental and computational approach using hydrogel channels

• Armel Boutchuen,
• Dell Zimmerman,
• Abdollah Arabshahi,
• John Melnyczuk and
• Soubantika Palchoudhury

Beilstein J. Nanotechnol. 2020, 11, 296–309, doi:10.3762/bjnano.11.22

• experimental tools for mimicking complex physiological environments at the preclinical stage. Here, we report a coupled experimental and computational fluid dynamics (CFD)-based novel in vitro approach to predict the flow velocity and binding of NP drug delivery systems during transport through vasculature

• . Poly(hydroxyethyl)methacrylate hydrogels were used to form soft cylindrical constructs mimicking vascular sections as flow channels for synthesized iron oxide NPs in these first-of-its-kind transport experiments. Brownian dynamics and material of the flow channels played key roles in NP flow, based on

• but a flow controlled by the surrounding fluid and Brownian dynamics at the lowest NP concentrations. The CFD model predicted a mass loss of 1.341% and 6.253% for the 4.12 g·mL−1 and 2.008 g·mL−1 inlet mass concentrations of the NPs, in close confirmation with the experimental results. This further

Using gold nanoparticles to detect single-nucleotide polymorphisms: toward liquid biopsy

• María Sanromán Iglesias and
• Marek Grzelczak

Beilstein J. Nanotechnol. 2020, 11, 263–284, doi:10.3762/bjnano.11.20

• sensitivity are currently implemented to obtain reliable information on tumor-associated genetic modifications and to follow tumor dynamics [4][16][46][56]. These techniques are mainly modifications of the well-known polymerase chain reaction (PCR), establishing thus the state-of-the-art in clinics in the

• cost (200 US dollars). However, the time required to complete such an analysis exceeds several weeks, making it unfeasible for the fast monitoring of tumor dynamics. Therefore, point-of-care diagnostic tools that offer rapid (hours) discrimination of an individual mutation remain an aim to be pursued