Questo lavoro è stato sostenuto da Grant No. cbet-0651283 dal US National Science Foundation e Grant No. 117041PO9621 dalla tecnologia di raffreddamento avanzata.

1. Preparazione di nanoparticelle di silice per la deposizione <ol><li> Partendo con polvere di silice asciutta, preparare il campione per rivestimento mediante prima eliminando grandi aggregati. </li><li> Lavare le particelle di silice (diametro di 200 nm, acquistato da Gel-Tec Corp.) con etanolo (190 prove puro) e lasciare il campione sotto cappa aspirante fino a che tutti l&#39;umidità evapora con etanolo. </li><li> Setacciare le particelle attraverso una serie di maglie metalliche (US # 100-400), al fine di interrompere qualsiasi agglomerati rimanenti. </li><li> Particelle luogo e un piccolo bar agitatore magnetico nel reattore tubolare, come mostrato nella Figura 1. Particelle deve essere posizionato all&#39;interno della zona del plasma. </li><li> Sigillare la reattore di vetro inserendo un o-ring tra le due flange, uno alla fine del tubo di vetro e uno alla fine del tubo collegato alla pompa. </li><li> Installare l&#39;anello di serraggio in acciaio inox attorno le flange e serrare la vite intorno alla pinza. </li></ol> 2.Preparazione del sistema di aspirazione <ol><li> Riempire la trappola d&#39;azoto liquido, quindi consentire la superficie della trappola per raffreddarsi. Attendere 5 min. </li><li> Aggiungere isopropanolo nel gorgogliatore e connettersi al reattore a plasma. </li><li> Sigillare il gorgogliatore mettendo una gomma o-ring attorno al tubo di metallo e serrare il dado fino al luogo di tubo di collegamento gorgogliatore diventa sigillato. </li></ol> 3. Plasma processo di deposizione <ol><li> Posizionare il gorgogliatore in un bagno d&#39;acqua con temperatura di 34 ± 2 ° C. </li><li> Accendere il regolatore di flusso di gas argon e inserire 6,00 SCCM come il set point. </li><li> Aprire gradualmente la saracinesca che collega il tubo di vetro alla pompa quando la pompa è in funzione. Eseguire questo passaggio attentamente perché calo improvviso della pressione può causare le particelle per essere spazzato via dal flusso. Aspetta la pressione raggiunge i 200 mTorr, poi lasciare la saracinesca completamente aperta. </li><li> Posizionare l&#39;agitatore magnetico sotto il tubo di vetro e impostare la velocità a 100 rpm. </li><li> Collegate l&#39;anello di alluminio intorno al reattore tubolare di vetro alla radiofrequenza, RF, generatore e collegare il morsetto in acciaio inossidabile a terra. </li><li> Accendere la rete di adattamento (ENI MW-5D) prima e poi passare la linea AC e la potenza del generatore RF. Impostare la potenza di 30 W per l&#39;intero processo. </li><li> Dopo un periodo specifico di tempo (10, 20, o 40 min) spegnere la rete di adattamento, generatore RF, e la corrente alternata, rispettivamente. </li><li> Chiudere la valvola di non ritorno e quindi spegnere il regolatore di flusso di argon. Scollegare il gorgogliatore dalla valvola e gradualmente aumentare la pressione del reattore a quella atmosferica. </li><li> Aprire il morsetto e trasferire le particelle provenienti dal tubo in un piatto di plastica con una spatola metallica. </li></ol> 4. Preparazione di particelle Hollow dalla dissoluzione di materiale di riempimento <ol><li> Porre il campione sotto cappa aspirante per l&#39;intero processo di aggiunta di acido fluoridrico. </li><li> L&#39;acido fluoridrico è estremamente coL&#39;acido rrosive e l&#39;esposizione di occhi e pelle può causare danni permanenti. Usare occhiali con visiera e indossare un camice da laboratorio quando si maneggia HF. </li><li> Mescolare 10 ml di acido fluoridrico (Aldrich 49%) con 10 ml di acqua deionizzata e aggiungere al piatto di plastica che contiene le particelle rivestite. </li><li> Posizionare il piatto di plastica su un agitatore magnetico e consentire il nucleo sciogliere per 24 ore. </li><li> Dopo un giorno diluire il campione con 50 ml di acqua deionizzata e centrifugare il campione per 1 ora. Eliminare il livello di liquido nella parte superiore in un contenitore di plastica e trasferire lo strato inferiore che contiene le particelle in una capsula Petri di plastica. </li><li> Aggiungere 50 ml di acqua deionizzata e vortex e centrifugare il campione di nuovo. Smaltire dello strato superiore e trasferire lo strato di particelle in una capsula Petri pulito. </li><li> Lavare le particelle con etanolo, asciugare all&#39;aria il campione, e trasferire le particelle cave in un flacone con tappo e mantenere le particelle in un essiccatore. </li></ol> 5. Characterization della permeabilità (tasso di rilascio Core) Materiali: cloruro di potassio per i materiali di base <ol><li> Preparare 0,001 molare di cloruro di potassio (KCl), soluzione mescolando 0.0745 grammi di KCl con 1 litro di acqua deionizzata. </li><li> Riempire la bottiglia di vetro del modello costante atomizzatore uscita 3076 e installare il tappo del flacone. </li><li> Collegare il tubo flessibile dell&#39;aria compressa ad un essiccatore membrana, che è collegata all&#39;ingresso del gas del nebulizzatore. Quindi attaccare un filtro per il tubo di scarico al fine di raccogliere nanoparticelle KCl. </li><li> Aprire gradualmente la valvola dell&#39;aria compressa e lasciare che il flusso d&#39;aria attraverso l&#39;essiccatore a membrana. Lasciare le particelle si accumulano nel filtro per 5 h. </li><li> Chiudere la valvola di aria compressa e rimuovere con cura il filtro e raccogliere le particelle. Collocare le particelle in un essiccatore prima del processo di rivestimento. </li><li> Seguire il protocollo 2 e 3, al fine di ottenere particelle di KCl uniformemente rivestite. </li><li> Mescolare KCl rivestito con 10 ml di acqua deionizzata water in un flaconcino di vetro. Per mescolare completamente il campione, cadere un agitatore magnetico nella soluzione e lasciarlo su un agitatore magnetico. Incubare il campione a 25 ° C. </li><li> Inserire la conducibilità metro sonda (Thermo Orion modello 105) nel flaconcino e registrare la conducibilità oltre 30 giorni. </li></ol> 6. Risultati rappresentativi Abbiamo applicato questo processo ad una varietà di materiali di base, contenenti ossidi di (silice), sali (KCl) e metalli (Al), come mostrato nella Figura 2. Microscopio elettronico a trasmissione è stata utilizzata per confermare l&#39;uniformità radiale dei film e per misurare il loro spessore. Siamo riusciti particelle rivestite vanno da 37 nm a 200 nm di diametro (Figura 2), ma non vi è alcuna limitazione fondamentale sulla dimensione delle particelle che possono essere trattati con questo metodo. Il tasso di deposizione guscio è di circa 1 nm / min. Questo tasso piuttosto lenta permette di controllare lo spessore dei film abbastanzaaccuratamente tramite il tempo di deposizione. Il plasma-polimerizzato guscio è una barriera permeabile, come dimostrato dal fatto che il materiale dell&#39;anima può rimosso mediante attacco chimico o dissoluzione. Figura 3 mostra i gusci vuoti che rimangono dopo il nucleo di silice viene rimosso. La rimozione del nucleo è completa e l&#39;uniformità radiale e spessore dei film sono piuttosto elevati. Ai fini della valutazione della permeabilità attraverso questi film, si commutato KCl come materiale del nucleo in quanto la dissoluzione di KCl può essere controllato facilmente attraverso la conducibilità ionica della soluzione. Figura 4 mostra il rilascio di KCl dal nucleo di quattro campioni con diverso spessore, 20 nm, 40 nm, 75 nm e 95 nm, rispettivamente. KCl particelle rivestite sono state sospese in acqua e la conducibilità della soluzione è stata seguita per un periodo di 30 giorni. Oltre ai quattro campioni, un controllo che consiste di particelle non rivestite KCl stata anche monitorata. Non rivestiti particelle KCl sopprimere PrioratiLVE entro un tempo molto breve di circa 1 min. Al contrario, KCl rivestito mostra una velocità di rilascio molto più lento. Il profilo di rilascio delle particelle rivestite è caratterizzata da scoppio iniziale che avviene all&#39;interno hr primo, seguito da un rilascio più lento che richiede diversi giorni per completare, a seconda dello spessore del film. <img alt="Figura 1" src="/files/ftp_upload/4113/4113fig1.jpg" /> Figura 1. Rappresentazione schematica della preparazione di nanoparticelle, deposizione al plasma, e la formazione di particelle cava. <img alt="Figura 2" src="/files/ftp_upload/4113/4113fig2.jpg" /> Figura 2. Immagini TEM di carta patinata (a), (b) particelle di silice con d = 200 nm, (c) di particelle di silice con d = 37 nm, (d) d alluminio con circa 100 nm, e (e) di particelle con KCl D = 100 nm <img alt="Figura 3" src="/files/ftp_upload/4113/4113fig3.jpg" /> Figura 3. TEM immagini di particelle vuote dopo l&#39;incisione (a), (b) nucleo di silice con diametro di 200 nm, e (c) core KCl. <img alt="Figura 4" src="/files/ftp_upload/4113/4113fig4.jpg" /> Figura 4. Effetto dello spessore del guscio sul profilo di rilascio. Il grafico mostra il riquadro rilascio durante la prima ora.

<ol>
	<li>Xu, X., Asher, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+Utilization+of+Monodisperse+Hollow+Polymeric+Particles+in+Photonic+Crystals.">Synthesis and Utilization of Monodisperse Hollow Polymeric Particles in Photonic Crystals.</a> Journal of the American Chemical Society. 126, 7940-7945 (2004).</li><li>Lou, X., Archer, L., Yang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hollow+Micro-/nanostructures:+Synthesis+and+Applications.">Hollow Micro-/nanostructures: Synthesis and Applications.</a> Advanced Material. 20, (2008).</li><li>Kim, D. J., Kang, J. Y., Kim, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coating+of+TiO2+Thin+Films+on+Particles+by+a+Plasma+Chemical+Vapor+Deposition+Process.">Coating of TiO2 Thin Films on Particles by a Plasma Chemical Vapor Deposition Process.</a> Advanced Powder Technology. 21, 136-140 (2010).</li><li>Marino, E., Huijser, T., Creyghton, Y., van der Heijden, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+Coating+of+Copper+Oxide+Nanoparticles+Using+Atmospheric+Pressure+Plasmas.">Synthesis and Coating of Copper Oxide Nanoparticles Using Atmospheric Pressure Plasmas.</a> Surface and Coatings Technology. 201, 9205-9208 (2007).</li><li>Hakim, L., King, D., Zhou, Y., Gump, C., George, S., Weimer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoparticle+Coating+for+Advanced+Optical,+Mechanical+and+Rheological+Properties.">Nanoparticle Coating for Advanced Optical, Mechanical and Rheological Properties.</a> Advanced Functional Materials. 17, 3175-3181 (2007).</li><li>Kim, S. H., Kim, J., Kang, B., Uhm, H. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superhydrophobic+CFx+Coating+via+In-Line+Atmospheric+RF+Plasma+of+He-CF4-H2.">Superhydrophobic CFx Coating via In-Line Atmospheric RF Plasma of He-CF4-H2.</a> Langmuir. 21, 12213-12217 (2005).</li></ol>

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Una delle maggiori sfide nel rivestimento di nanoparticelle è quello di fornire una chimica compatibile tra il rivestimento e il 1,2 substrato. La metodologia qui descritto ha il vantaggio che non è materiale specifico. Polimeri plasma mostra eccellente adesione su una varietà di substrati, compresi i metalli duri (Figura 2 (c)), silice (Figura 2 (c)), silicio, o materiali morbidi (per esempio, polimeri) senza la necessità di alcuna modifica speciale della superficie <sup...

<table border="1"><tbody><tr><td> Particelle di silice </td><td> Geltech Inc. </td><td></td><td></td></tr><tr><td> Cloruro di potassio (cristalli) </td><td> EMD Chemicals Inc. </td><td></td><td></td></tr><tr><td> Alcol isopropilico (99,9%) </td><td> Sigma-Aldrich </td><td></td><td></td></tr><tr><td> L&#39;acido fluoridrico (48-51%) </td><td> VWR </td><td></td><td></td></tr><tr><td> Tubi e flange </td><td> Swagelok </td><td></td><td> diametro di 1 pollice e ¼ </td></tr><tr><td> sgrossatura pompa </td><td> Edwards </td><td></td><td></td></tr><tr><td> trappola di azoto liquido </td><td> A &amp; N Corporation </td><td></td><td></td></tr></tbody></table>

encapsulation and permeability characteristics of plasma polymerized hollow particles

In questo protocollo, core-shell nanostrutture vengono sintetizzati mediante deposizione chimica da fase vapore maggiore plasma. Si produce una barriera amorfo da plasma polimerizzazione di isopropanolo su vari substrati solidi, tra silice e cloruro di potassio. Questa tecnica versatile viene usato per trattare nanoparticelle e nanopolveri con dimensioni variabili da 37 nm a 1 micron, depositando film il cui spessore può essere ovunque da 1 nm a verso l&#39;alto di 100 nm. Dissoluzione del nucleo consente di studiare il tasso di permeazione attraverso il film. In questi esperimenti, si determina il coefficiente di diffusione del KCl attraverso la pellicola barriera da nanocristalli LKC rivestimento e successivamente monitorare la conducibilità ionica delle particelle rivestite sospese in acqua. L&#39;interesse primario in questo processo è l&#39;incapsulamento e il rilascio ritardato di soluti. Lo spessore del guscio è una delle variabili indipendenti, che controllano la velocità di rilascio. Ha un forte effetto sul tasso didi rilascio, che aumenta da sei ore di rilascio (spessore del guscio è di 20 nm) a un lungo periodo di rilascio più di 30 giorni (spessore del guscio è di 95 nm). Il profilo di rilascio mostra un comportamento caratteristico: un rapido rilascio (35% dei materiali finali) durante i primi cinque minuti dopo l&#39;inizio della dissoluzione, e un rilascio più lento fino a tutti i materiali di base uscire.

Watch this Scientific Journal Video about Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles at JoVE.com

Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles

Abbiamo usato maggiore plasma deposizione di vapore chimico per depositare pellicole sottili che variano da pochi nm a 100 nm su diverse particelle nanodimensionate di vari materiali. Abbiamo successivamente etch del materiale del nucleo per produrre nanoshells cave cui permeabilità è controllata dallo spessore del guscio. Abbiamo caratterizzano la permeabilità di questi rivestimenti piccoli soluti e dimostrano che queste barriere possono fornire un rilascio prolungato del materiale del nucleo più giorni.

Caratteristiche di incapsulamento e di permeabilità di plasma particelle polimerizzate Hollow

In this protocol, core-shell nanostructures are synthesized by plasma enhanced chemical vapor deposition. We produce an amorphous barrier by plasma ...

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10.7K Views.  The Pennsylvania State University. Abbiamo usato maggiore plasma deposizione di vapore chimico per depositare pellicole sottili che variano da pochi nm a 100 nm su diverse particelle nanodimensionate di vari materiali. Abbiamo successivamente etch del materiale del nucleo per produrre nanoshells cave cui permeabilità è controllata dallo spessore del guscio. Abbiamo caratterizzano la permeabilità di questi rivestimenti piccoli soluti e dimostrano che queste barriere possono fornire un rilascio prolungato...

Video: Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles

Investigation of Early Plasma Evolution Induced by Ultrashort Laser Pulses

Early plasma is generated owing to high intensity laser irradiation of target and the subsequent target material ionization. Its dynamics plays a significant role in laser-material interaction, especially in the air environment1-11.
Early plasma evolution has been captured through pump-probe shadowgraphy1-3 and interferometry1,4-7. However, the studied time frames and applied laser parameter ranges are limited. For example, direct examinations of plasma front locations and electron number densities within a delay time of 100 picosecond (ps) with respect to the laser pulse peak are still very few, especially for the ultrashort pulse of a duration around 100 femtosecond (fs) and a low power density around 1014 W/cm2. Early plasma generated under these conditions has only been captured recently with high temporal and spatial resolutions12. The detailed setup strategy and procedures of this high precision measurement will be illustrated in this paper. The rationale of the measurement is optical pump-probe shadowgraphy: one ultrashort laser pulse is split to a pump pulse and a probe pulse, while the delay time between them can be adjusted by changing their beam path lengths. The pump pulse ablates the target and generates the early plasma, and the probe pulse propagates through the plasma region and detects the non-uniformity of electron number density. In addition, animations are generated using the calculated results from the simulation model of Ref. 12 to illustrate the plasma formation and evolution with a very high resolution (0.04 ~ 1 ps).
Both the experimental method and the simulation method can be applied to a broad range of time frames and laser parameters. These methods can be used to examine the early plasma generated not only from metals, but also from semiconductors and insulators.

An experimental method to examine the early plasma evolution induced by ultrashort laser pulses is described. Using this method, high quality images of early plasma are obtained with high temporal and spatial resolutions. A novel integrated atomistic model is used to simulate and explain the mechanisms of early plasma.

Indagine su Evolution Plasma precoce indotta da impulsi laser ultracorti

Early plasma is generated owing to high intensity laser irradiation of target and the subsequent target material ionization. Its dynamics plays a ...

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Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids

An experimental study is performed to measure the terminal settling velocities of spherical particles in surfactant based shear thinning viscoelastic (VES) fluids. The measurements are made for particles settling in unbounded fluids&#160;and fluids between parallel walls. VES fluids over a wide range of rheological properties are prepared and rheologically characterized. The rheological characterization involves steady shear-viscosity and dynamic oscillatory-shear measurements to quantify the viscous and elastic properties respectively. The settling velocities under unbounded conditions are measured in beakers having diameters at least 25x the diameter of particles. For measuring settling velocities between parallel walls, two experimental cells with different wall spacing are constructed. Spherical particles of varying sizes are gently dropped in the fluids and allowed to settle. The process is recorded with a high resolution video camera and the trajectory of the particle is recorded using image analysis software. Terminal settling velocities are calculated from the data.
The impact of elasticity on settling velocity in unbounded fluids is quantified by comparing the experimental settling velocity to the settling velocity calculated by the inelastic drag predictions of Renaud et al.1&#160;Results show that elasticity of fluids can increase or decrease the settling velocity. The magnitude of reduction/increase is a function of the rheological properties of the fluids and properties of particles. Confining walls are observed to cause a retardation effect on settling and the retardation is measured in terms of wall factors.

This paper demonstrates the experimental procedure to measure terminal settling velocities of spherical particles in surfactant-based shear thinning viscoelastic fluids. Fluids over a wide range of rheological properties are prepared and settling velocities are measured for a range of particle sizes in unbounded fluids and fluids between parallel walls.

Misurazione sperimentale della velocità di sedimentazione delle particelle sferiche in fluidi viscoelastici a base di tensioattivi non raffinati e confinati

An experimental study is performed to measure the terminal settling velocities of spherical particles in surfactant based shear thinning viscoelastic ...

How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a stable and continuous operation of the plasma is possible and the plasma torch can be used for many different applications. On one hand, the hot (3,600 K gas temperature) plasma can be used for chemical processes and on the other hand the cold afterglow (temperatures down to almost RT) can be applied for surface processes. For example chemical syntheses are interesting volume processes. Here the microwave plasma torch can be used for the decomposition of waste gases which are harmful and contribute to the global warming but are needed as etching gases in growing industry sectors like the semiconductor branch. Another application is the dissociation of CO2. Surplus electrical energy from renewable energy sources can be used to dissociate CO2 to CO and O2. The CO can be further processed to gaseous or liquid higher hydrocarbons thereby providing chemical storage of the energy, synthetic fuels or platform chemicals for the chemical industry. Applications of the afterglow of the plasma torch are the treatment of surfaces to increase the adhesion of lacquer, glue or paint, and the sterilization or decontamination of different kind of surfaces. The movie will explain how to ignite the plasma solely by microwave power without any additional igniters, e.g., electric sparks. The microwave plasma torch is based on a combination of two resonators &#8212; a coaxial one which provides the ignition of the plasma and a cylindrical one which guarantees a continuous and stable operation of the plasma after ignition. The plasma can be operated in a long microwave transparent tube for volume processes or shaped by orifices for surface treatment purposes.

This movie shows how an atmospheric plasma torch can be ignited by microwaves with no additional igniters and provides a stable and continuous plasma operation suitable for plenty of applications.

Come Ignite una Pressione atmosferica Microonde torcia al plasma senza alcuna accenditori supplementari

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a ...

Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing technology is used to fabricate particles with slender arms connected at a common center. Shapes explored are crosses (two perpendicular rods), jacks (three perpendicular rods), triads (three rods in triangular planar symmetry), and tetrads (four arms in tetrahedral symmetry). Methods for producing on the order of 10,000 fluorescently dyed particles are described. Time-resolved measurements of their orientation and solid-body rotation rate are obtained from four synchronized videos of their motion in a turbulent flow between oscillating grids with R&#955; = 91. In this relatively low-Reynolds number flow, the advected particles are small enough that they approximate ellipsoidal tracer particles. We present results of time-resolved 3D trajectories of position and orientation of the particles as well as measurements of their rotation rates.

We use 3D printing to fabricate anisotropic particles in the shapes of jacks, crosses, tetrads, and triads, whose alignments and rotations in turbulent fluid flow can be measured from multiple simultaneous video images.

Metodi per misurare l&#39;orientamento e rotazione Tasso di particelle in turbolenza 3D-stampati

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing ...

Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles

Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must be smaller than the incident wavelength of sound and the width of the fluidic channels are typically tens to hundreds of micrometers across, acoustofluidic devices typically use ultrasonic waves generated from a piezoelectric transducer pulsating at high frequencies (in the megahertz range). At characteristic frequencies that depend on the geometry of the device, it is possible to induce the formation of standing waves that can focus particles along desired fluidic streamlines within a bulk flow. Here, we describe a method for the fabrication of acoustophoretic devices from common materials and clean room equipment. We show representative results for the focusing of particles with positive or negative acoustic contrast factors, which move towards the pressure nodes or antinodes of the standing waves, respectively. These devices offer enormous practical utility for precisely positioning large numbers of microscopic entities (e.g., cells) in stationary or flowing fluids for applications ranging from cytometry to assembly.

Acoustofluidic devices use ultrasonic waves within microfluidic channels to manipulate, concentrate and isolate suspended micro and nanoscopic entities. This protocol describes the fabrication and operation of such a device supporting bulk acoustic standing waves to focus particles in a central streamline without the aid of sheath fluids.

Realizzazione e di funzionamento dei dispositivi che supportano Acoustofluidic Bulk onde acustiche piedi per guaina di messa a fuoco di particelle

Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must ...

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic

X-ray spectra provide a wealth of information on high temperature plasmas; for example electron temperature and density can be inferred from line intensity ratios. By using a Johann spectrometer viewing the plasma, it is possible to construct profiles of plasma parameters such as density, temperature, and velocity with good spatial and time resolution. However, benchmarking atomic code modeling of X-ray spectra obtained from well-diagnosed laboratory plasmas is important to justify use of such spectra to determine plasma parameters when other independent diagnostics are not available. This manuscript presents the operation of the High Resolution X-ray Crystal Imaging Spectrometer with Spatial Resolution (HIREXSR), a high wavelength resolution spatially imaging X-ray spectrometer used to view hydrogen- and helium-like ions of medium atomic number elements in a tokamak plasma. In addition, this manuscript covers a laser blow-off system that can introduce such ions to the plasma with precise timing to allow for perturbative studies of transport in the plasma.

X-ray spectra provide a wealth of information on high temperature plasmas. This manuscript presents the operation of a high wavelength resolution spatially imaging X-ray spectrometer used to view hydrogen- and helium-like ions of medium atomic number elements in a tokamak plasma.

L&#39;applicazione di X-ray Imaging cristallo Spettroscopia per l&#39;uso come ad alta temperatura del plasma di diagnostica

X-ray spectra provide a wealth of information on high temperature plasmas; for example electron temperature and density can be inferred from line ...

Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling immensely. However, in soft electronics, in which organic semiconductors play a critical role, the devices will be bent or folded repeatedly. The effect of bending on the crystal packing and thus the charge transport is crucial to the performance of the device. In this manuscript, we describe the protocol to bend a single crystal of 5,7,12,16-tetrachloro-6,13-diazapentacene (TCDAP) in the field-effect transistor configuration and to obtain reproducible I-V characteristics upon bending the crystal. The results show that bending a field-effect transistor prepared on a flexible substrate results in nearly reversible yet opposite trends in charge mobility, depending on the bending direction. The mobility increases when the device is bent toward the top gate/dielectric layer (upward, compressive state) and decreases when bent toward the crystal/substrate side (downward, tensile state). The effect of bending curvature was also observed, with greater mobility change resulting from higher bending curvature. It is suggested that the intermolecular &#960;-&#960; distance changes upon bending, thereby influencing the electronic coupling and the subsequent carrier transport ability.

This manuscript describes the bending process of an organic single crystal-based field-effect transistor to maintain a functioning device for electronic property measurement. The results suggest that bending causes changes in the molecular spacing in the crystal and thus in the charge hopping rate, which is important in flexible electronics.

Effetto di piegare sulle caratteristiche elettriche di transistor ad effetto di campo basati su cristallo Flexible Organic singolo

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling ...

An Atmospheric Pressure Plasma Setup to Investigate the Reactive Species Formation

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. The reactions of cold plasma with the surrounding atmosphere yield a variety of reactive species, which can define its effectiveness. While efficient development of cold plasma therapy requires kinetic models, model benchmarking needs empirical data. Experimental studies of the source of reactive species detected in aqueous solutions exposed to plasma are still scarce. Biomedical plasma is often operated with He or Ar feed gas, and a specific interest lies in investigation of the reactive species generated by plasma with various gas admixtures (O2, N2, air, H2O vapor, etc.) Such investigations are very complex due to difficulties in controlling the ambient atmosphere in contact with the plasma effluent. In this work, we addressed common issues of &#39;high&#39; voltage kHz frequency driven plasma jet experimental studies. A reactor was developed allowing the exclusion of ambient atmosphere from the plasma-liquid system. The system thus comprised the feed gas with admixtures and the components of the liquid sample. This controlled atmosphere allowed the investigation of the source of the reactive oxygen species induced in aqueous solutions by He-water vapor plasma. The use of isotopically labelled water allowed distinguishing between the species originating in the gas phase and those formed in the liquid. The plasma equipment was contained inside a Faraday cage to eliminate possible influence of any external field. The setup is versatile and can aid in further understanding the cold plasma-liquid interactions chemistry.

An experimental setup was created for the helium-operated kHz frequency plasma jet. The setup includes a cage for the plasma power supply and jet and an in-house built reactor to monitor plasma-induced reactive species without the interference of the ambient atmosphere.

Una configurazione plasma a pressione atmosferica per Indagare sulla formazione reattiva Specie

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. ...

Spark Plasma Sintering Apparatus Used for the Formation of Strontium Titanate Bicrystals

A spark plasma sintering apparatus was used as a novel method for diffusion bonding of two single crystals of strontium titanate to form bicrystals with one twist grain boundary. This apparatus utilizes high uniaxial pressure and a pulsed direct current for rapid consolidation of material. Diffusion bonding of strontium titanate bicrystals without fracture, in a spark plasma sintering apparatus, is possible at high pressures due to the unusual temperature dependent plasticity behavior of strontium titanate. We demonstrate a method for the successful formation of bicrystals at accelerated time scales and lower temperatures in a spark plasma sintering apparatus compared to bicrystals formed by conventional diffusion bonding parameters. Bond quality was verified by scanning electron microscopy. A clean and atomically abrupt interface containing no secondary phases was observed using transmission electron microscopy techniques. Local changes in bonding across the boundary was characterized by simultaneous scanning transmission electron microscopy and spatially resolved electron energy-loss spectroscopy.

A viable technique for the formation of strontium titanate bicrystals at high pressure and fast heating rate via the spark plasma sintering apparatus is developed.

Spark Plasma Sintering apparecchio utilizzato per la formazione di titanato di stronzio Bicrystals

A spark plasma sintering apparatus was used as a novel method for diffusion bonding of two single crystals of strontium titanate to form bicrystals with ...

Optimization, Test and Diagnostics of Miniaturized Hall Thrusters

Miniaturized spacecraft and satellites require smart, highly efficient and durable low-thrust thrusters, capable of extended, reliable operation without attendance and adjustment. Thermochemical thrusters which utilize thermodynamic properties of gases as a means of acceleration have physical limitations on their exhaust gas velocity, resulting in low efficiency. Moreover, these engines demonstrate extremely low efficiency at small thrusts and may be unsuitable for continuously operating systems which provide real-time adaptive control of the spacecraft orientation, velocity and position. In contrast, electric propulsion systems which use electromagnetic fields to accelerate ionized gases (i.e., plasmas) do not have any physical limitation in terms of exhaust velocity, allowing virtually any mass efficiency and specific impulse. Low-thrust Hall thrusters have a lifetime of several thousand hours. Their discharge voltage ranges between 100 and 300 V, operating at a nominal power of &lt;1 kW. They vary from 20 to 100 mm in size. Large Hall thrusters can provide fractions of millinewton of thrust. Over the past few decades, there has been an increasing interest in small mass, low power, and high efficiency propulsion systems to drive satellites of 50-200 kg. In this work, we will demonstrate how to build, test, and optimize a small (30 mm) Hall thruster capable of propelling a small satellite weighing about 50 kg. We will show the thruster operating in a large space environment simulator, and describe how thrust is measured and electric parameters, including plasma characteristics, are collected and processed to assess key thruster parameters. We will also demonstrate how the thruster is optimized to make it one of the most efficient small thrusters ever built. We will also address challenges and opportunities presented by new thruster materials.

Here, we present a protocol to test and optimize space propulsion systems based on miniaturized Hall-type thrusters.

Ottimizzazione, Test e diagnostica di propulsori a effetto Hall miniaturizzato

Miniaturized spacecraft and satellites require smart, highly efficient and durable low-thrust thrusters, capable of extended, reliable operation without ...