Gotowe bibliografie tematyczne / Nanoscale Symmetry

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Gotowa bibliografia na temat „Nanoscale Symmetry”

Autor: Grafiati

Data publikacji: 7 września 2023

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Artykuły w czasopismach na temat "Nanoscale Symmetry"

Shao, Yu-Tsun, i Jian-Min Zuo. "Nanoscale symmetry fluctuations in ferroelectric barium titanate, BaTiO3". Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 73, nr 4 (19.07.2017): 708–14. http://dx.doi.org/10.1107/s2052520617008496.

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Crystal charge density is a ground-state electronic property. In ferroelectrics, charge is strongly influenced by lattice andvice versa, leading to a range of interesting temperature-dependent physical properties. However, experimental determination of charge in ferroelectrics is challenging because of the formation of ferroelectric domains. Demonstrated here is the scanning convergent-beam electron diffraction (SCBED) technique that can be simultaneously used for imaging ferroelectric domains and identifying crystal symmetry and its fluctuations. Results from SCBED confirm the acentric tetragonal, orthorhombic and rhombohedral symmetry for the ferroelectric phases of BaTiO3. However, the symmetry is not homogeneous; regions of a few tens of nanometres retaining almost perfect symmetry are interspersed in regions of lower symmetry. While the observed highest symmetry is consistent with the displacive model of ferroelectric phase transitions in BaTiO3, the observed nanoscale symmetry fluctuations are consistent with the predictions of the order–disorder phase-transition mechanism.

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McGrath, R. "Fabricating novel symmetry nanoscale systems using quasicrystal surfaces". Acta Crystallographica Section A Foundations of Crystallography 61, a1 (23.08.2005): c37—c38. http://dx.doi.org/10.1107/s0108767305098405.

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Lin-Chung, P. J., i A. K. Rajagopal. "Magnetoplasma oscillations in nanoscale tubules with helical symmetry". Physical Review B 49, nr 12 (15.03.1994): 8454–63. http://dx.doi.org/10.1103/physrevb.49.8454.

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Lin-Chung, P. J., i A. K. Rajagopal. "Electronic excitations in nanoscale systems with helical symmetry". Journal of Physics: Condensed Matter 6, nr 20 (16.05.1994): 3697–706. http://dx.doi.org/10.1088/0953-8984/6/20/009.

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Su, Jiaye, Keda Yang i Hongxia Guo. "Asymmetric transport of water molecules through a hydrophobic conical channel". RSC Adv. 4, nr 76 (2014): 40193–98. http://dx.doi.org/10.1039/c4ra07034h.

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Muller, Eric A., Benjamin Pollard, Hans A. Bechtel, Peter van Blerkom i Markus B. Raschke. "Infrared vibrational nanocrystallography and nanoimaging". Science Advances 2, nr 10 (październik 2016): e1601006. http://dx.doi.org/10.1126/sciadv.1601006.

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Molecular solids and polymers can form low-symmetry crystal structures that exhibit anisotropic electron and ion mobility in engineered devices or biological systems. The distribution of molecular orientation and disorder then controls the macroscopic material response, yet it is difficult to image with conventional techniques on the nanoscale. We demonstrated a new form of optical nanocrystallography that combines scattering-type scanning near-field optical microscopy with both optical antenna and tip-selective infrared vibrational spectroscopy. From the symmetry-selective probing of molecular bond orientation with nanometer spatial resolution, we determined crystalline phases and orientation in aggregates and films of the organic electronic material perylenetetracarboxylic dianhydride. Mapping disorder within and between individual nanoscale domains, the correlative hybrid imaging of nanoscale heterogeneity provides insight into defect formation and propagation during growth in functional molecular solids.

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Wang, Chunyan, Dahu Chang, Junfei Wang, Qilong Gao, Yinuo Zhang, Chunyao Niu, Chengyan Liu i Yu Jia. "Size and crystal symmetry breaking effects on negative thermal expansion in ScF₃ nanostructures". Physical Chemistry Chemical Physics 23, nr 43 (2021): 24814–22. http://dx.doi.org/10.1039/d1cp02809j.

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Melcher, Christof. "Chiral skyrmions in the plane". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 470, nr 2172 (8.12.2014): 20140394. http://dx.doi.org/10.1098/rspa.2014.0394.

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Magnets without inversion symmetry are a prime example of a solid-state system featuring topological solitons on the nanoscale, and a promising candidate for novel spintronic applications. Magnetic chiral skyrmions are localized vortex-like structures, which are stabilized by antisymmetric exchange interaction, the so-called Dzyaloshinskii–Moriya interaction. In continuum theories, the corresponding energy contribution is, in contrast to the classical Skyrme mechanism from nuclear physics, of linear gradient dependence and breaks the chiral symmetry. In the simplest possible case of a ferromagnetic energy in the plane, including symmetric and antisymmetric exchange and Zeeman interaction, we show that the least energy in a class of fields with unit topological charge is attained provided the Zeeman field is sufficiently large.

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Borodin, Y. V., K. V. Sysolov, V. R. Rande, G. V. Vavilova i O. Starý. "Spectroscopy of nanoscale crystalline structural elements". Bulletin of the Karaganda University. "Physics" Series 99, nr 3 (30.09.2020): 46–53. http://dx.doi.org/10.31489/2020ph3/46-53.

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The study of structural elements, nanoparticles, microblocks and other nanoscale objects was an important part of the study of crystals non-equilibrium properties. The behavior of nanoscale structures allows us to judge the dynamics of the crystal lattice during doping, deformation, and interactions with radiation. Along with x-ray and electron microscopic studies, optical methods for determining the size of nanoscale objects, the energy of their electrons, and the symmetry of electronic States are increasingly being used. Among nanoscale objects, proton-separated structural elements (PSE) attract special attention in connection with the development of crystal structure block-hierarchical (BH) model. In this paper, we consider the possibility of calculating the size of PSE crystals in a model of quantum-dimensional structures. According to this model except values of the crystal potential in PSE, you should consider the area of high electron density, the existence of which is beyond the scope of conventional theory. Experimental data allow us to determine the position of this zone as localized around the atomic core of the PSE. Note that the atomic backbone generally coincides with the unit cell, that is, it consists of the same number of atoms and has the same point symmetry group.

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Park, Jun-Hee, Abdoulaye Ndao, Wei Cai, Liyi Hsu, Ashok Kodigala, Thomas Lepetit, Yu-Hwa Lo i Boubacar Kanté. "Symmetry-breaking-induced plasmonic exceptional points and nanoscale sensing". Nature Physics 16, nr 4 (17.02.2020): 462–68. http://dx.doi.org/10.1038/s41567-020-0796-x.

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Rozprawy doktorskie na temat "Nanoscale Symmetry"

Lane, Paul David. "Nanoscale surface modification studied by reflection anisotropy spectroscopy". Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/5660.

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The development and control of nanoscale properties is a major goal in science and technology; for the development of such technologies it is important that there are experimental techniques which allow the monitoring of development processes in real time and in a range of environments. With this in mind much effort has been invested in the development of surface sensitive optical probes. One such technique, reflection anisotropy spectroscopy (RAS), has been applied successfully to a number of different problems since its development in the mid 1980’s. RAS as a surface specific technique is very sensitive to small changes to surface morphology, electronic structure and molecular orientation. This makes RAS a useful technique to study nanoscale changes occurring at surfaces and it is applied here to three such systems, in an attempt to develop a better understanding of both the systems and the technique. Surface defects arising from thermal processing and etching of the sample are considered and are found to have a significant effect on both the electronic structure and the morphology of the surface. The time and temperature dependences of the RAS signatures allow the monitoring of surface dynamic processes. The deposition of a monolayer of adsorbate molecules onto the surface allows a new interface to be created. Monitoring the evolution of this surface during deposition provides information about both the substrate surface and the adsorba te covered surface; a theoretical framework has been outlined to show how the sources of anisotropy from multiple thin film layers combine to give a RAS signal. Azimuth dependent RAS (ADRAS) is known to provide information on surface symmetry and can be used to determine molecular orientation. There are also a number of other angles which affect the RA spectrum from a sample. A tilted molecule causes a breakdown in surface symmetry; this work shows how such an effect can be observed.

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Carter-Fenk, Kevin D. "Design and Implementation of Quantum Chemistry Methods for the Condensed Phase: Noncovalent Interactions at the Nanoscale and Excited States in Bulk Solution". The Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu161617640330551.

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Książki na temat "Nanoscale Symmetry"

Fu, Huaxiang. Unusual properties of nanoscale ferroelectrics. Redaktorzy A. V. Narlikar i Y. Y. Fu. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199533053.013.19.

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This article describes the unusual properties of nanoscale ferroelectrics (FE), including widely tunable polarization and improved properties in strained ferroelectric thin films; polarization enhancement in superlattices; polarization saturation in ferroelectric thin films under very large inplane strains; occurrence of ferroelectric phase transitions in one-dimensional wires; existence of the toroidal structural phase in ferroelectric nanoparticles; and the symmetry-broken phase-transition path when one transforms a vortex phase into a polarization phase. The article first considers some of the critical questions on low-dimensional ferroelectricity before discussing the theoretical approaches used to determine the properties of ferroelectric nanostructures. It also looks at 2D ferroelectric structures such as surfaces, superlattices and thin films, along with 1D ferroelectric nanowires and ferroelectric nanoparticles.

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Strasberg, Philipp. Quantum Stochastic Thermodynamics. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192895585.001.0001.

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Abstract Processes at the nanoscale happen far away from the thermodynamic limit, far from equilibrium and are dominated by fluctuations and, perhaps, even quantum effects. This book establishes a consistent thermodynamic framework for such processes by combining tools from non-equilibrium statistical mechanics and the theory of open quantum systems. The book is accessible for graduate students and of interest to all researchers striving for a deeper understanding of the laws of thermodynamics beyond their traditional realm of applicability. It puts most emphasis on the microscopic derivation and understanding of key principles and concepts as well as their interrelation. The topics covered in this book include (quantum) stochastic processes, (quantum) master equations, local detailed balance, classical stochastic thermodynamics, (quantum) fluctuation theorems, strong coupling and non non-Markovian effects, thermodynamic uncertainty relations, operational approaches, Maxwell's demon and time-reversal symmetry, among other topics. Furthermore, the book treats a few applications in detail to illustrate the general theory and its potential for practical applications. These are single-molecule pulling experiments, quantum transport and thermoelectric effects in quantum dots, the micromaser and related set-ups in quantum optics.

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Części książek na temat "Nanoscale Symmetry"

Krishnan, Kannan M. "Diffraction of Electrons and Neutrons". W Principles of Materials Characterization and Metrology, 481–551. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198830252.003.0008.

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Electron scattering, significantly stronger than that for X-rays, is sensitive to surfaces and small volumes of materials. Low-energy electron diffraction (LEED) provides information on surface reconstruction and the arrangement of adsorbed atoms. Reflection high energy electron diffraction (RHEED) probes surface crystallography, and monitors, in situ, mechanisms of thin film growth. Transmission electron diffraction reveals a planar cross-section of the reciprocal lattice, where intensities are products of the structure and lattice amplitude factors determined by the overall shape of the specimen. The amplitude of any diffracted beam at the exit surface oscillates with thickness (fringes) and the excitation error (bend contours). Selected area diffraction produce spot or ring patterns, where low-index zone-axis orientations reflect the symmetry of the crystal, and double-diffraction shows positive intensities even for reflections forbidden by extinction rules. Kikuchi lines appear as pairs of dark and bright lines, and help in tilting the specimen. A focused probe produces convergent beam electron diffraction (CBED), useful for symmetry analysis at nanoscale resolution. Neutrons interact with the nucleus and the magnetic moment of the atom via the spin of the neutron; the latter finds particular use in studies of magnetic order. The atomic scattering factor for neutrons shows negligible angular dependence.

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Brandão, Jeovani, Marcos Vinicius Puydinger dos Santos i Fanny Béron. "Stabilizing Zero-Field Skyrmions at Room-Temperature in Perpendicularly Magnetized Multilayers". W Magnetic Skyrmions. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97179.

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Magnetic skyrmions are twirling spin structures observed in bulk, thin films, and multilayers with several features for both fundamental physics understanding and spintronic applications, i.e., nanoscale size, efficient transport under electrical current, and topological protection against defects. However, most magnetic skyrmions have been observed under the assistance of an out-of-plane magnetic field, which may limit their use in magnetic memory technologies. In this chapter, we review and present two recent mechanisms to create zero-field skyrmions at room-temperature in ferromagnetic multilayers. First, by tuning the perpendicular magnetic anisotropy (PMA) and remnant magnetization (near magnetization saturation) in unpatterned symmetric multilayer systems, it was achieved a transition from worm-like domains to isolated skyrmions. Besides, we present how to find stable zero-field skyrmions in arrays of ferrimagnetic discs by tailoring their diameter. Both methods demonstrate a robust route to stabilize zero-field skyrmions at room temperature, thus providing an important contribution to possible applications of these textures in the next generation of skyrmionics devices.

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Streszczenia konferencji na temat "Nanoscale Symmetry"

Yang, M., L. Q. Yang, W. Lu, L. Li, Q. X. Liu i Y. W. Zhang. "Numerical Simulation of Nonlinear Flow and Heat Transfer in a Sudden Expansion and Contraction Channel". W ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/mnhmt2016-6532.

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Numerical simulation of forced flow in sudden-expansion followed by sudden-contraction rectangular channel was presented for the whole flow region. The nonlinear flow and heat transfer characteristics were investigated by various Reynolds number and geometrical dimension and the critical Reynolds numbers under different conditions have been calculated. The results show flow and heat transfer from symmetric state to asymmetric state with the increase of Re. When Re<Rec (critical Reynolds number for flow transformation), the symmetric state is stable. On the other hand, when Re ≥Rec, the flow loses stability and from symmetric to asymmetric via a symmetry-breaking bifurcation. And the heat transfer performance have relevant characteristics as fluid flow.

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Rao, Zhonghao, Yutao Huo i Yimin Li. "The Lattice Boltzmann Investigation for the Melting Process of Phase Change Material in an Inclining Cavity". W ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/mnhmt2016-6343.

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The solid-liquid phase transition process is of significant importance the widely usage of phase change material (PCM), including in thermal energy storage and maintaining working temperature. In this paper, a phase change lattice Boltzmann (LB) model has been established to investigate the effects of inclining angle on the melting process in a cavity filled with PCM, considering three kinds of heat flux distribution: uniform distribution, linear distribution and parabolic symmetry distribution. The simulations results show that for all the heat flux distributions, the slight clockwise rotation of cavity is able to accelerate the melting process. Furthermore, when more heat is transported into the cavity through the middle part (parabolic symmetry distribution) or bottom part (linear distribution), the effects of cavity clockwise rotation on temperature field are more than that of anticlockwise rotation.

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Boehm, Alex, Sylvain D. Gennaro, Chloe F. Doiron, Thomas E. Beechem, Michael B. Sinclair, Igal Brener, Raktim Sarma i Taisuke Ohta. "Nanoscale Optical Mode Imaging and Spectroscopy of Dielectric Metasurfaces Based on the Bound State in Continuum". W CLEO: Fundamental Science. Washington, D.C.: Optica Publishing Group, 2023. http://dx.doi.org/10.1364/cleo_fs.2023.ff3c.1.

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We use photoemission electron microscopy for hyperspectral imaging of electromagnetic field localization in broken-symmetry III-V semiconductor metasurfaces with high selectivity to characterize complex resonant mode profiles, determine coherent interaction lengths, and corroborate FDTD simulations.

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Jaculbia, Rafael B., Hiroshi Imada, Kuniyuki Miwa, Takeshi Iwasa, Masato Takenaka, Bo Yang, Emiko Kazuma, Norihiko Hayazawa, Tetsuya Taketsugu i Yousoo Kim. "Vibrational symmetry of a single molecule revealed by tip-enhanced Raman spectroscopy". W JSAP-OSA Joint Symposia. Washington, D.C.: Optica Publishing Group, 2019. http://dx.doi.org/10.1364/jsap.2019.18p_e208_9.

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The scanning tunneling microscope (STM) is a powerful tool for studying various nanoscale materials with atomic scale spatial resolution. Despite the atom scale spatial sensitivity however, the STM lacks the chemical sensitivity crucial to the investigation of nanomaterials. Raman spectroscopy on the other hand has a very strong chemical sensitivity but its spatial resolution is highly restricted by the diffraction limit of light allowing only about several hundreds of nanometer resolution. Combining these two powerful experiments into a technique called STM-tip enhanced Raman spectroscopy (STM-TERS) alleviates the limitation of STM and Raman allowing for simultaneous subnanometer spatial resolution and high chemical sensitivity.

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Barker, Alex J., Brant Cage, Stephen Russek, Ruchira Garg, Robin Shandas i Conrad R. Stoldt. "Tailored Nanoscale Contrast Agents for Magnetic Resonance Imaging". W ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81503.

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Two potential molecular imaging vectors are investigated for material properties and magnetic resonance imaging (MRI) contrast improvement. Monodisperse magnetite (Fe3O4) nanocrystals ranging in size from 7 to 22 nm are solvothermally synthesized by thermolysis of Fe(III) acetylacetonate (Fe(AcAc)3) both with and without the use of heptanoic acid (HA) as a capping ligand. For the resulting Fe3O4 nanocrystals, X-Ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and superconducting quantum interference device magnetometry (SQUID) is used to identify the average particle size, monodispersity, crystal symmetry, and magnetic properties of the ensembles as a function of time. The characterization study indicates that the HA synthesis route at 3 hours produced nanoparticles with the greatest magnetic anisotropy (15.8 × 104 J/m3). The feasibility of Fe8 single molecule magnets (SMMs) as a potential MRI contrast agent is also examined. SQUID magnetization measurements are used to determine anisotropy and saturation of the potential agents. The effectiveness of the Fe3O4 nanocrystals and Fe8 as potential MRI molecular probes is evaluated by MRI contrast improvement using 1.5 mL phantoms dispersed in de-ionized water. Results indicate that the magnetically optimized Fe3O4 nanocrystals and Fe8 SMMs hold promise for use as contrast agents based on the reported MRI images and solution phase T1/T2 shortening.

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Zhang, Wei, i Jinliang Xu. "Multichannel Effect of Condensation Flow and Heat Transfer in Horizontally Positioned Silicon Microchannels With the Channel Depth Down to Thirty Microns". W ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer. ASMEDC, 2008. http://dx.doi.org/10.1115/mnht2008-52315.

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Multichannel effect is an important issue in micro condensers. In the present paper, we fabricated a silicon chip, consisting of three rectangular microchannels, with each width of 800 microns but depth down to 30 microns. Saturated vapor of water enters the entrance of microchannels which were horizontally positioned. There are two types of flow patterns: (1) the annular flow at high inlet pressures; (2) the quasi-stable bubble slug in the microchannel upstream followed by the isolated bubbles downstream, at moderate or low inlet pressures. For the second flow pattern, the downstream isolated bubble is formed by breaking up: (1) the single vapor thread connecting the upstream bubble slug and the detaching bubble; (2) the dual vapor threads synchronously in the center microchannel; (3) the dual vapor threads non-synchronously in the side microchannels. The flow patterns in the two side channels are symmetry against the center microchannel. The upstream bubble slug is shorter in the side channels than in the center channel. The temperature gradient across the chip width direction accounts for the non-synchronously break-up of the dual vapor threads connecting the bubble slug and the detaching bubble, in the side channels, indicating the multichannel effects.

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Mo, Gary C. H., i Daniel Y. Kwok. "Self-Breakup of Microdroplets by Molecular Self-Assembly". W ASME 3rd International Conference on Microchannels and Minichannels. ASMEDC, 2005. http://dx.doi.org/10.1115/icmm2005-75179.

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We report a method of producing minute micro-droplets through nanoscale molecular self-assembly from a given liquid volume without external input. By the branching of hydrophobic restrictions, the drop is forced to separate while translating on a flat surface. Symmetry in the drop front wetted perimeter conduces to equal division of the drop. We show that at least 3 divisions can be performed sequentially on a 1.5 microliter drop to give minute droplets of approximately equal volumes. A division of carrier liquid volume by 1/23 enables multiple analyses on many separate stations in one microfluidic application.

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Donkov, Alexander A., Steffen Hardt, Sudarshan Tiwari i Axel Klar. "Coupling of Heat and Momentum Transfer Between Nanostructured Surfaces". W ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18061.

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Heat transfer between nanostructured surfaces separated by a thin gas film is studied in the free-molecular flow and in the transition regime. Besides topographic features the surfaces are characterized by regions with different boundary conditions displaying either diffuse or specular reflection of the molecules. The thermal conductivity of the materials on both sides of the gas film is assumed to be very high such that isothermal conditions may be applied at both surfaces. We analyze the problem using a combination of analytical techniques in the free-molecular flow regime and Monte-Carlo simulations. Under certain conditions, when the surfaces are held at different temperatures heat transfer is accompanied by a transfer of momentum such that a force is created parallel to the surfaces. This force can be significant and vanishes in the classical regime when the continuum transport equations can be applied. It is only observed if the reflection symmetry in a direction parallel to the surfaces is broken. We derive an analytical expression for the thermally-induced force as a function of the geometric parameters characterizing the surface topography and compare the results to Monte-Carlo simulations. The latter provide numerical solutions of the Boltzmann equation both in the free-molecular flow and in the transition regime. The scenario studied points to a novel method for conversion of thermal into kinetic energy and may find applications in small-scale energy converters.

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Yeo, Leslie Y., i James R. Friend. "Surface Acoustic Waves: A New Paradigm for Driving Ultrafast Biomicrofluidics". W ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18517.

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Surface acoustic waves (SAWs), which are 10 MHz order surface waves roughly 10 nm in amplitude propagating on the surface of a piezoelectric substrate, can offer a powerful method for driving fast microfluidic actuation and microparticle or biomolecule manipulation. We demonstrate that sessile drops can be linearly translated on planar substrates or fluid can be pumped through microchannels at typically one to two orders of magnitude faster than that achievable through current microfluidic technologies. Micromixing can be induced in the same microchannel in which fluid is pumped using the SAW simply by changing the SAW frequency to superimpose a chaotic oscillatory flow onto the uniform through flow. Strong inertial microcentrifugation for micromixing and particle concentration or separation can also be induced via symmetry-breaking. At low SAW amplitudes below that at which flow commences, the transverse standing wave that arises across the microchannel afford particle aggregation and hence sorting on nodal lines. Other microfluidic manipulations are also possible with the SAW. For example, capillary waves excited on a sessile drop by the SAW can be exploited for microparticle or nanoparticle collection and sorting. At higher amplitudes, the large substrate accelerations drives rapid destabilization of the drop interface giving rise to inertial liquid jets or atomization to produce 1–10 μm monodispersed aerosol droplets. These have significant implications for microfluidic chip mass spectrometry interfacing or pulmonary drug delivery. The atomization also provides a convenient means for the synthesis of 150–200 nm polymer or protein particles or to encapsulate proteins, peptides and other therapeutic molecules within biodegradable polymeric shells for controlled release drug delivery. The atomization of thin films containing polymer solutions, in addition, gives produces a unique regular, long-range spatial polymer spot patterning effect whose size and spacing are dependent on the SAW frequency, thus offering a simple and powerful method for surface patterning without requiring physical or chemical templating.

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Nosrati, Reza, Mehrdad Raisee i Ahmad Nourbakhsh. "Modeling of Electroosmotic Nanoflows With Overlapped Double Layer". W ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2011. http://dx.doi.org/10.1115/icnmm2011-58087.

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In the present paper a new model is proposed for electric double layer (EDL) overlapped in nanochannels. The model aimed to obtain a deeper insight of transport phenomena in nanoscale. Two-dimensional Nernst and ionic conservation equations are used to obtain electroosmotic potential distribution in flow field. In the proposed study, transport equations for flow, ionic concentration and electroosmotic potential are solved numerically via finite volume method. Moreover, Debye-Hu¨ckle (DH) approximation and symmetry condition, which limit the application, are avoided. Thus, the present model is suitable for prediction of electroosmotic flows through nanochannels as well as complicated asymmetric geometries with large nonuniform zeta potential distribution. For homogeneous zeta potential distribution, it has been shown that by reduction of channel height to values comparable with EDL thickness, Poisson-Boltzmann model produces inaccurate results and must be avoided. Furthermore, for overlapped electric double layer in nanochannels with heterogeneous zeta potential distribution it has been found that the present model returns modified ionic concentration and electroosmotic potential distribution compare to previous EDL overlapped models due to 2D solution of ionic concentration distribution. Finally, velocity profiles in EDL overlapped nanochannels are investigated and it has been showed that for pure electroosmotic flow the velocity profile deviates from the expected plug-like profile towards a parabolic profile.

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