Search results for " light"
showing 10 items of 1141 documents
Quality control of gold nanoparticles as pharmaceutical ingredients
2019
Abstract Nanoparticles are being developed for a wide range of medical applications such as, controlled release, drug delivery systems or imagery, theranostics, implants…. For the moment, there is no legal definition of nanoparticles or nanomaterials for therapeutic use. The specific case of gold nanoparticles is not an exception: their current definition as nanoparticle material does not correspond to classic pharmaceutical ingredients as described in Pharmacopoeias. In this study, more than 30 different batches of citrate stabilized gold nanoparticles (AuNP) were synthesized and analyzed thanks to both classical approaches (UV–Vis spectrophotometry, dynamic light scattering coupled or not…
A synchrotron radiation X-ray scattering study of aqueous solutions of native DNA
1999
Synchrotron radiation small-angle X-ray scattering (SAXS) was used to investigate solutions of native DNA at different ionic strengths and temperatures. The mass per unit length, radius of gyration of the cross-section of DNA and apparent second virial coefficient (A2) were obtained from Zimm plots in the rodlike particle approximation. The values of A2 obtained in this way are positive and almost constant indicating that the repulsive interactions still influence the scattering patterns at resolutions as high as 5-8 nm. SAXS measurements in continuous temperature scans indicate that the rod approximation is valid over a wide temperature range during DNA melting and confirm that the rodlike…
Scaling On-Chip Entangled Photon States to Higher Dimensions
2017
Considerable efforts have recently focused on advancing quantum information pro- cessing by increasing the number of qubits (the simplest unit of quantum information) in nonclassical systems such as ultracold atoms and superconducting circuits. A complementary approach to scale up infor- mation content is to move from two-level (qubit) to multilevel (quDit) systems.
On-chip frequency combs and telecommunications signal processing meet quantum optics
2018
Entangled optical quantum states are essential towards solving questions in fundamental physics and are at the heart of applications in quantum information science. For advancing the research and development of quantum technologies, practical access to the generation and manipulation of photon states carrying significant quantum resources is required. Recently, integrated photonics has become a leading platform for the compact and cost-efficient generation and processing of optical quantum states. Despite significant advances, most on-chip nonclassical light sources are still limited to basic bi-photon systems formed by two-dimensional states (i.e., qubits). An interesting approach bearing …
Electromagnetic structure of few-nucleon ground states
2015
Experimental form factors of the hydrogen and helium isotopes, extracted from an up-to-date global analysis of cross sections and polarization observables measured in elastic electron scattering from these systems, are compared to predictions obtained in three different theoretical approaches: the first is based on realistic interactions and currents, including relativistic corrections (labeled as the conventional approach); the second relies on a chiral effective field theory description of the strong and electromagnetic interactions in nuclei (labeled $\chi$EFT); the third utilizes a fully relativistic treatment of nuclear dynamics as implemented in the covariant spectator theory (labeled…
Quantum light depolarization: the phase-space perspective
2008
Quantum light depolarization is handled through a master equation obtained by coupling dispersively the field to a randomly distributed atomic reservoir. This master equation is solved by transforming it into a quasiprobability distribution in phase space and the quasiclassical limit is investigated.
Mesoscopic gels at low agarose concentration: perturbation effects of ethanol
1997
Aqueous agarose solutions at low concentrations (0.5 g/liter) were temperature quenched below the spinodal line to form mutually disconnected mesoscopic gels. In the presence of 6% ethanol, these solutions, obtained by quenching at the same temperature depth as in pure water, appear much more fluid, as determined by probe diffusion experiments. We show by static and dynamic light scattering that this can be explained by the solvent-mediated effects of ethanol, leading to a globular shape of mesoscopic agarose gels, rather than to an extended rodlike structure observed in pure water. Our findings show the significant effects of solvent perturbations on particle condensation and, therefore, m…
Numerical procedures and their practical application in PV modules analyses. Part I: air mass
2019
Abstract The subject of the article is aspects of PV modules and cells measurement, with the use of natural sunlight. A light source is an important element during calibration and measurements of solar cells and modules. All designers of artificial light sources try to recreate natural light using so called measurement tables. The correctly performed measurement, i.e. meeting all the appropriate atmospheric conditions, guarantees obtaining the result with the use of a reference spectrum. The article has two main aims. The first aim of the article is to answer the question asked earlier - if the sunlight spectrum registered in appropriate conditions is so good that it serves as the reference…
Colloidal electro-phoresis in the presence of symmetric and asymmetric electro-osmotic flow
2018
We characterize the electro-phoretic motion of charged sphere suspensions in the presence of substantial electro-osmotic flow using a recently introduced small angle super-heterodyne dynamic light scattering instrument (ISASH-LDV). Operation in integral mode gives access to the particle velocity distribution over the complete cell cross-section. Obtained Doppler spectra are evaluated for electro-phoretic mobility, wall electro-osmotic mobility and particle diffusion coefficient. Simultaneous measurements of differing electro-osmotic mobilities leading to asymmetric solvent flow are demonstrated in a custom made electro-kinetic cell fitting standard microscopy slides as exchangeable sidewall…
Nanoparticles Size Distribution Assessment During Early Synthesis Stages
2021
Nanotechnology, an innovative field of material science, designs and produces nanostructures materials with unique properties that make them suited for various bioengineering applications. The shape and the dimension are the main variables depending on the method of synthesis or chemical precursors. Silver nanoparticles obtained through chemical synthesis exhibit as strong antibacterial effect if their size lays in a well-defined range. However, a small size of such particles, in the range of nanometers to several tens of nanometers, requires specific techniques as Dynamic Light Scattering or Transmission Electron Microscopy, both being affected by certain assumptions or by the high cost an…