この作品は、高度な冷却技術から米国国立科学財団とグラント第117041PO9621からグラント号CBET-0651283によってサポートされていました。

1。蒸着用シリカナノ粒子の調製<ol><li>乾燥したシリカ粉末で始まる、最初の大きな凝集体を排除することによりコーティングのサンプルを準備します。 </li><li>エタノールを用いてシリカ粒子（ジェルテック（株）から購入した200nmの直径）、（190プルーフ純粋）を洗浄し、エタノールですべての水分が蒸発するまでヒュームフードの下でサンプルのままにしておきます。 </li><li>残りの集積を壊すために金属製のメッシュ（米国＃100から400）、一連の粒子をふるいにかける。 </li><li> 図1に示すように、場所粒子および管状反応器の小さなマグネチックスターラーバー、。粒子はプラズマゾーン内に配置する必要があります。 </li><li>二つのガラス管の端に1つ、ポンプに接続されているパイプの端に1つ、フランジ間にOリングを配置することによって、ガラス反応器をシールします。 </li><li>フランジと手がクランプの周りにネジを締め周りのステンレス製クランプリングを取り付けます。 </li></ol> 2。真空システムの準備<ol><li>液体窒素トラップを埋めるし、トラップの表面が冷たくなることができます。 5分待ちます。 </li><li>バブラーにイソプロパノールを追加し、プラ​​ズマ反応器に接続します。 </li><li>金属パイプの周りにゴム製O-リングを配置することにより、バブラーを密封し、バブラーに接続するパイプのところまでナットを締めて密封することになります。 </li></ol> 3。プラズマ成膜プロセス<ol><li> ±2℃に34の温度を水浴中でバブラーを配置</li><li>アルゴンガス流量制御装置の電源をオンにし、セットポイントとして6.00 SCCMを入力してください。 </li><li>徐々にポンプが作動している間にポンプにガラス管を接続し、ゲートバルブを開きます。圧力の急激な減少は、粒子は流れによって吹き飛ばされる場合がありますので、慎重にこの手順を実行してください。圧力は200ミリトールに到達するまで待ち、その後、ゲートバルブが完全に開いたままにします。 </li><li>ガラス管の下でマグネチックスターラーを置き、100 rで速度を設定する午後。 </li><li>無線周波数に管状のガラス反応器、RF、発電機の周りにアルミリングを接続し、グランドにステンレス鋼クランプを接続します。 </li><li>マッチングネットワークをオンにします（ENI MW-5D）最初にして、ACラインとRF信号発生器の電源を入れます。全体のプロセスのために30 Wの電力を設定します。 </li><li>時間の特定の期間（10、20、または40分）の後にそれぞれマッチングネットワーク、RFジェネレータ、AC電源をオフにします。 </li><li>チェックバルブを閉じ、アルゴン流量コントローラをオフにします。バルブからバブラーを切断し、徐々に大気中に原子炉圧力を増加させます。 </li><li>クランプを開き、金属製のへらを用いてプラスチック皿にチューブから粒子を転送します。 </li></ol> 4。コア材料の溶解による中空粒子の調製<ol><li>フッ化水素酸を加えることの全体のプロセスのためのヒュームフードの下にサンプルを置きます。 </li><li>フッ化水素酸は非常に協力です。それに目や皮膚のrrosive酸の暴露は永久的な損傷を引き起こす可能性があります。フェースシールドとゴーグルを使用してHFを取り扱う際には白衣を着用してください。 </li><li> 10ミリリットルの脱イオン水でフッ化水素酸（アルドリッチ49％）10mlを混合し、被覆粒子が含まれているプラ​​スチック製の皿に追加します。 </li><li>マグネチックスターラーでプラスチック製の皿を置き、コアは24時間溶解することができます。 </li><li> 1日後に50ミリリットルの脱イオン水でサンプルを希釈し、1時間のためにサンプルを遠心します。プラスチック容器の上部に液体層を破棄して、プラスチック製のペトリ皿の中で粒子を含む底層に転送します。 </li><li> 50ミリリットルの脱イオン水と渦のサンプルを追加し、再度遠心します。最上層の処分とクリーンなペトリ皿の中で粒子層を転送します。 </li><li>エタノールで粒子を洗浄し、空気は、サンプルを乾燥し、キャップをバイアルに中空粒子を転送し、デシケーター中で粒子を保持します。 </li></ol> 5。キャラ透水性のcterization（コアリリースのレート） 材料：コア材料の塩化カリウム<ol><li> 1リットルの脱イオン水と塩化カリウムの混合0.0745グラム、0.001モルの塩化カリウム（KCl）溶液を調製します。 </li><li>一定の出力アトマイザーモデル3076のガラスボトルを記入し、ボトルキャップをインストールします。 </li><li>噴霧器のガス入口に接続されている膜式ドライヤに圧縮空気ホースを接続します。その後のKClナノ粒子を収集するために、出口ホースにフィルターを取り付けます。 </li><li>徐々に圧縮空気のバルブを開いて、膜式ドライヤを介して空気の流れをみましょう。粒子が5時間のフィルタに蓄積されることができます。 </li><li>圧縮空気のバルブを閉じて、慎重にフィルタを削除し、粒子を収集します。コー​​ティングプロセスの前に、デシケーター中で粒子を配置します。 </li><li>均一にコーティングされたのKCl粒子を得るためには、プロトコルバージョン2と3に従ってください。 </li><li> 10ミリリットルの脱イオンWAでコーティングされたKClを混ぜるガラスバイアルにTER。完全にサンプルを混ぜるために、溶液中にマグネチックスターラーをドロップして、マグネチックスターラー上におきます。 25℃でサンプルをインキュベート</li><li>バイアル中に導電率計プローブ（サーモオリオンモデル105）を挿入し、30日間の導電率を記録します。 </li></ol> 6。代表的な結果我々は図2に示すように、酸化物（シリカ）、塩（塩化カリウム）と金属（Al）を含むコア材料の様々な、このプロセスを適用しました。透過型電子顕微鏡は、膜の半径方向の均一性を確認し、その厚さを測定するために使用されています。我々は、37 nmの直径を200nm（ 図2）に至るまで成功した被覆粒子を持っていますが、この方法によって治療することができる粒子の大きさには根本的な制限はありません。シェルの沈着率は約1nm /分である。このむしろ遅い速度は非常に膜厚を制御することが可能になります正確に堆積時間を経由して。コア材料は、エッチング又は溶解除去ができるという事実によって示されるようにプラズマ重合シェルは、透過性の障壁となっている。 図3は、石英コアが削除された後に残った中空のシェルを示しています。コアの除去は完全であり、フィルムの半径方向の均一性と厚さはかなり高いです。これらのフィルムを介して透過性を評価する目的のために、我々はKClの溶解は、溶液のイオン伝導度を介して非常に簡単に監視することができますので、コア材料としてのKClに切り替えました。 図4は、4つのサンプルのコアからのKClの放出を示しています。異なる厚さを20nm、40nmで、75 nm、および95 nmと、それぞれ。コー​​ティングされたKClの粒子は、水に懸濁し、溶液の導電率は、30日間続いた。 4サンプルに加えて、コーティングされていないのKCl粒子からなる制御もモニターした。コー​​ティングされていないのKCl粒子disso約1分の非常に短い時間内にLVE。対照的に、コーティングされた塩化カリウムはかなり遅い放出速度を示しています。被覆粒子の​​放出プロファイルは、膜の厚さに応じて、完了するまでに数日かかりますはるかに遅いリリースに続いて、第一時間以内に行われる初期バーストによって特徴づけられる。 <img alt="図1" src="/files/ftp_upload/4113/4113fig1.jpg" /> 図1ナノ粒子の調製の模式図、プラズマ蒸着、および中空粒子形成。 <img alt="図2" src="/files/ftp_upload/4113/4113fig2.jpg" /> 図2 TEMコーティングの画像（A）、（B）dとシリカ粒子= 200 nmのは、d = 37 nmと（C）シリカ粒子、dを（d）のアルミ〜100 nm、および（e）はKClの粒子とD = 100nmの<img alt="図3" src="/files/ftp_upload/4113/4113fig3.jpg" /> 図3。TEM（）エッチング後の中空粒子の画像、（b）は200nmの直径を有するシリカは、コア、および（c）KClのコア。 <img alt="図4" src="/files/ftp_upload/4113/4113fig4.jpg" /> 図4。放出プロファイルのシェル厚さの影響。グラフ内の右上のグラフは、最初の時間の間にリリースを示しています。

<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>

利害の衝突が宣言されません。

コーティングナノ粒子における最大の課題の1つは、コーティングと基板1,2の間に互換性のある化学物質を提供することです。ここで説明した方法論は、それが材料固有ではないという利点があります。プラズマポリマーは、特別な表面改質3を必要とせずに硬い金属（ 図2（c））、シリカ（ 図2（c））、シリコン、または柔らかい材料（例えば、ポリ...

<table border="1"><tbody><tr><td>シリカ粒子</td><td> Geltech株式会社</td><td></td><td></td></tr><tr><td>塩化カリウム（結晶） </td><td> EMDケミカルズ</td><td></td><td></td></tr><tr><td>イソプロピルアルコール（99.9％） </td><td> Sigma-Aldrich社</td><td></td><td></td></tr><tr><td>フッ化水素酸（48から51パーセント） </td><td> VWR </td><td></td><td></td></tr><tr><td>パイプとフランジ</td><td>スウェージロック</td><td></td><td> ¼と1インチの直径</td></tr><tr><td>ポンプを荒</td><td>エドワーズ</td><td></td><td></td></tr><tr><td>液体窒素トラップ</td><td> ＆Nコーポレーション</td><td></td><td></td></tr></tbody></table>

encapsulation and permeability characteristics of plasma polymerized hollow particles

このプロトコルでは、コア·シェル型ナノ構造体は、プラズマ強化化学蒸着法により合成される。我々はシリカと塩化カリウムを含む様々な固体基板上にイソプロパノールのプラズマ重合による非晶質バリアを生成します。この汎用性の高い技術は、厚さ1nmから100nmの上方にどこにあってもかまいませんフィルムを堆積させることにより、37 nmから1ミクロンまでのサイズのナノ粒子とナノ粉末を治療するために使用されています。コアの解散は、私たちは、フィルムの透過率を検討することができます。これらの実験では、我々は、コーティングKCLナノ結晶でバリア膜を介してKClの拡散係数を決定し、その後水に懸濁した被覆粒子の​​イオン伝導度を監視します。このプロセスの主要な関心は、カプセル化と溶質の遅延のリリースです。シェルの厚さは、我々の放出速度を制御することにより、独立変数の一つです。それは速度に強い影響を持っているリリースの、その6時間のリリース（シェルの厚さは20nmである）から30日間の長期的なリリース（シェルの厚さは95 nmである）に増加します。解散の開始後最初の5分の間に高速のリリース（最終材料の35％）、およびコア材料のすべてまで遅いリリースが出てくる：放出プロフィールは、特徴的な挙動を示しています。

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

我々は、数nmから様々な材料のナノサイズの粒子の数100nmまでの薄膜を蒸着させるためにプラズマ強化化学蒸着を使用しています。透水性シェルの厚さによって制御される中空ナノシェルを生成するために我々は、その後エッチコア材料。私たちは小さな溶質にこれらのコーティングの透過性を特徴づけるこれらの障壁は数日間、コア材料の徐放を提供することができることを示している。

プラズマ重合中空粒子のカプセル化と透水特性

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

encapsulation-permeability-characteristics-plasma-polymerized-hollow

Research

Education

JoVE Core

JoVE Journal

Civil Engineering

Engineering

Unit 1

Permeability of Concrete

SCIENTISTS IN ACTION

10.7K ビュー.  The Pennsylvania State University. 我々は、数nmから様々な材料のナノサイズの粒子の数100nmまでの薄膜を蒸着させるためにプラズマ強化化学蒸着を使用しています。透水性シェルの厚さによって制御される中空ナノシェルを生成するために我々は、その後エッチコア材料。私たちは小さな溶質にこれらのコーティングの透過性を特徴づけるこれらの障壁は数日間、コア材料の徐放を提供す?...

ビデオ: 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.

超短レーザーパルスにより誘起された初期プラズマの進化の解明

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

工学

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.

追加のイグナイタずに大気圧マイクロ波プラズマトーチに点火する方法

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.

乱流で3Dプリント粒子の配向および回転速度を測定するための方法

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.

作製とAcoustofluidicのデバイスの動作は、粒子のフォーカシングSheathlessためのバルク弾性定在波を支援

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.

高温プラズマ診断として使用するためのX線イメージングクリスタル分光法を適用します

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.

フレキシブル有機単結晶ベースの電界効果トランジスタの電気的特性に曲げの影響

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.

反応種の形成を調査するための大気圧プラズマのセットアップ

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

Plasma-assisted Molecular Beam Epitaxy of N-polar InAlN-barrier High-electron-mobility Transistors

Plasma-assisted molecular beam epitaxy is well suited for the epitaxial growth of III-nitride thin films and heterostructures with smooth, abrupt interfaces required for high-quality high-electron-mobility transistors (HEMTs). A procedure is presented for the growth of N-polar InAlN HEMTs, including wafer preparation and growth of buffer layers, the InAlN barrier layer, AlN and GaN interlayers and the GaN channel. Critical issues at each step of the process are identified, such as avoiding Ga accumulation in the GaN buffer, the role of temperature on InAlN compositional homogeneity, and the use of Ga flux during the AlN interlayer and the interrupt prior to GaN channel growth. Compositionally homogeneous N-polar InAlN thin films are demonstrated with surface root-mean-squared roughness as low as 0.19 nm and InAlN-based HEMT structures are reported having mobility as high as 1,750 cm2/V&#8729;sec for devices with a sheet charge density of 1.7 x 1013 cm-2.

Molecular beam epitaxy is used to grow N-polar InAlN-barrier high-electron-mobility transistors (HEMTs). Control of the wafer preparation, layer growth conditions and epitaxial structure results in smooth, compositionally homogeneous InAlN layers and HEMTs with mobility as high as 1,750 cm2/V&#8729;sec.

N極性のInAlNバリア高電子移動度トランジスタのプラズマ支援分子線エピタキシ

Plasma-assisted molecular beam epitaxy is well suited for the epitaxial growth of III-nitride thin films and heterostructures with smooth, abrupt ...

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.

チタン酸ストロンチウム双結晶の形成に用いられるプラズマ焼結装置をスパーク

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.

最適化、テストおよび小型ホールスラ スターの診断

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