Name: scanning squid study of vortex manipulation by local contact
Uploaded: 2017-02-01T14:00:00.000+00:00
Duration: 6 min 53 s
Description: Watch this Scientific Journal Video about Scanning SQUID Study of Vortex Manipulation by Local Contact at JoVE.com

Biz süperiletken filmler sağlamak için Bar-Ilan Üniversitesi&#39;nden A. Sharoni teşekkür ederim. Bu araştırma, Avrupa Araştırma Konseyi Hibe ERC-2014-STG- 639792 tarafından desteklenen, Marie Curie Kariyer Entegrasyon Hibe FP7-PEOPLE-2012-CIG-333799 ve İsrail Bilim Vakfı Hibe ISF-1102-1113.

Bir Tarama KALAMAR Sistemine 1. Erişim <ol><li> Bir çip 9, 10, sopa kayma kaba hareket aşamasında ve ince hareket için bir piezo-tabanlı tarayıcı üzerinde fabrikasyon bir KALAMAR sensörü içeren bir tarama KALAMAR sistemi kullanın. Bkz: Şekil 1. </li><li> pikap döngü etrafında bir köşeye KALAMAR çipi parlatın. çip malzemesi tüm yol alma döngü kaldırılması gerekiyor. <ol><li> Yavaşça 5 mikron 0.5 manyetik olmayan parlatma kağıt kullanarak, SQUID lehçe. NOT: parlatma aşamadan sonra pikap döngü örneği ile, yakın, ya da temas getirilebilir. </li></ol></li></ol> Doğru Akım (DC) püskürtme ile Niyobyum (Nb) İnce Film 2. Biriktirme <ol><li> Bir alt-tabakanın elde edilir. Bu çalışma, silikon oksit, 500 nm olan bir bor içerikli silikon bir alt-tabakanın kullanımı. Böyle SrTiO ve MgO gibi diğer alt tabakalar mümkündür. </li><li> Bir baz pressu ulaşmakodasında 10 -7 Torr yeniden. Ön sputter 10 dakika için 1.8 a / s bir depozisyon oranı 2.4 mTorr basıncında bir argon ortamında% 99,95 Nb hedefi, oda sıcaklığında buharlaştırma odasını. Odasındaki taban basıncı az 10 -7 Torr olduğunda bırakma işlemi sadece başlayabilirsiniz unutmayın. Basınç öncesi püskürtme aşaması yüksek yineleyin ise. </li><li> odasında yerleştirilmesidir. </li><li> 1.8 a / s &#39;lik bir yerleştirme oranı 2.4 mTorr basıncında argon ortamında,% 99.95 Nb hedeften oda sıcaklığında püskürtülerek Deposit Nb ince film. </li></ol> 3. Numune ucu Hizalama <ol><li> girdapları taşırken çip ucu örneği ile temas edinceye kadar bu aşamada, numune ile sensör çipi aynı hizaya getirin. Bunu elde etmek için, en az 4 ° &#39;lik bir hizalama açı kullanılır. </li><li> bir dielektrik tabaka, bir iletken plaka üzerinde, esnek bir konsol Tutkal. Ardından, KALAMAR chi tutkalkonsol üzerinde s. konsol ve statik plakası arasındaki kapasitans numune ve uygulanan stres ölçüde temas belirler. </li><li> mikroskop yük örneği. belirlenmiş bir örnek örnek Tutkal bir cila veya gümüş macun kullanarak monte edin. Z piezo elemanı (Şekil 1a) için montaj Tutkal. </li><li> Bir kontrolöre sopa kayma kaba hareket sistemini bağlayın. </li><li> ön ve çip yan - iki açıdan optik görüntüleme ayarlayın. çip ön ve yanlarından birine yönlendirilir için aşamaları üzerine yerleştirilmiş iki teleskop kullanın. </li><li> sensörün yansıma numunesi üzerinde görünür böylece Z sopa kayma kaba hareket sahne kullanarak, sensörden 1 um mesafeye örnek taşıyın. NOT: SQUID zarar verebilir bu aşamada numune ve sensör arasında bağlantı kurun. </li><li> S zarar görmesini önlemek için Z sopa kayma kaba hareket sahne kullanılarak 1 mm uzakta sensörden - 0.5 örnek TaşıSTERLİN. </li><li> Eşit ön açıları elde etmek için hizalama vidaları (Şekil 1a) döndürün (yani, Şekil 1c görüldüğü gibi çipin ucu yanları, onun yansıması ile yapmak açıları). </li><li> algılayıcıdan 1 um&#39;lik bir mesafe için örnek getirin. açıları kontrol edin ve gerekirse adım 3.7 ve 3.8 tekrarlayın. </li><li> Sensör ve örnek (Şekil 1d) arasında 4 derecelik bir açı elde etmek için hizalama vidaları döndürün. çip ucu numunesi ile temas eder bir parçası olduğundan emin olun. </li></ol> 4. Ölçümler <ol><li> 4 K soğutma sistemi tarama kafası (Şekil 1a) yükleyin. NOT: Tarama kafası soğuk plaka bağlı ve bir vakum can çevrili olmalıdır. Dış manyetik alan (birkaç Gauss düşük alanlar bu çalışma için yeterli) uygulanması için teneke etrafında bir bobin tel. Mu-metal kalkan ile bu kurulumu örtün. </li><li> Magne mevcudiyetinde serintik alan, mikroskop çevreleyen bobin üzerinden akım uygulanarak. İstenilen girdap yoğunluğu elde etmek için dikkatli alan kuvvetini seçin. Bekleme süresi alanını hesaplamak için 1Φ 0 = 20.7 G / um 2 kullanın. Örneğin, bir 10 um 10 tarafından um alanında 10 girdapların için, 2.07 G. geçerlidir </li><li> (10 K üzerinde, Nb için ısı) süperiletkenlik geçiş sıcaklığının üzerinde yeni bir girdap yoğunluk ısı örnek değiştirmek için. Yeni bir alan uygulayın. </li><li> 4.2 K. Serin örnek </li><li> manyetik alan kapatın. SQUID açın. </li><li> sopa kayma kaba hareket sistemini kullanarak SQUID yakın örnek taşıyın. <ol><li> KALAMAR çip yakın örnek taşımak için Z-sopa kayma küp artan gerilimler uygulayın. </li><li> Bir kapasitans köprüsü (tipik 0.1-1 V) ile kapasitans okumak için konsol ve plaka arasındaki gerilim uygulanmalıdır. </li><li> Z piezo elemanı gerilimi Sweep. konsol ve plat arasındaki kapasitans ölçüne. kapasitans büyük bir değişiklik olursa, örnek SQUID çip ile temas halindedir. </li><li> Örnek çipi ile temas yapmadıysanız, adımları yineleyin 4.6.1-4.6.3 temas görülünceye kadar. </li><li> İsteğe bağlı: o kişi düşük voltajlı (0 - Z piezo uygulanan 10 V) oluşur, böylece ucu ve numune arasındaki mesafeyi ayarlamak için kurs hareketi kullanın. </li><li> temas olduğunda, tekrar yüzeyinin eğim açılarının belirlenmesi ve sensöre göre numune düzlemini tanımlamak için çeşitli konumlarda 4.6.2-4.6.3 adımları. </li></ol></li><li> sensöre numunenin taşımak için X ve Y, piezo elemanları üzerindeki voltajı hareket ettirin. Girdap dağılımının haritasının çıkartılması için, uç ve örnek arasındaki temas olmaksızın, örneğin üzerine sabit bir yükseklikte tarar. X ve Y yerlere göre Z piezo gerilimi değiştirerek sabit tarama yüksekliğe ulaşmak ve 4.6 tanımlanan düzleme. </li><li> bir girdap seçin ve arou taramand tam da merkezinde konumunu belirlemek için. girdap konum değil temas noktasına, kalamar en pikap döngü göreceli olduğunu unutmayın. </li><li> SQUID kapatın. </li><li> Bir sonraki girdap merkezine z piezo ve ya musluğa touchdown geriliminden daha yüksek bir gerilim uygulayın ya da istenilen bir yere numune üzerinde yavaş yavaş (numune ile temas halinde) sensörüne sürükleyerek girdap süpürün. girdap dokunun doğru veya süpürme yönde hareket edecektir. Tipik değerler 2-5 V uygulanacak z piezo gerilimine eklemek için </li><li> SQUID açın. </li><li> temas etmeden sabit bir yükseklikte tekrar görüntü girdap yeni konumunu bulmak için. </li></ol>

<ol>
	<li>Olson Reichhardt, C. J., Hastings, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Do+Vortices+Entangle?.">Do Vortices Entangle?.</a> Phys. Rev. Lett. 92, 157002 (2004).</li><li>Milo&#353;evi&#263;, M. V., Berdiyorov, G. R., Peeters, F. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluxonic+cellular+automata.">Fluxonic cellular automata.</a> Appl. Phys. Lett. 91, 212501 (2007).</li><li>Kalisky, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scanning+Probe+Manipulation+of+Magnetism+at+the+LaAlO3/SrTiO3+Heterointerface.">Scanning Probe Manipulation of Magnetism at the LaAlO3/SrTiO3 Heterointerface.</a> Nano Lett. 12, 4055-4059 (2012).</li><li>Silva, C. C. D. S., Van de Vondel, J., Morelle, M., Moshchalkov, V. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+multiple+reversals+of+a+ratchet+effect.">Controlled multiple reversals of a ratchet effect.</a> Nature. 440, 651-654 (2006).</li><li>Kalisky, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+of+single+vortices+in+grain+boundaries:+I-V+characteristics+on+the+femtovolt+scale.">Dynamics of single vortices in grain boundaries: I-V characteristics on the femtovolt scale.</a> Appl. Phys. Lett. 94, 202504 (2009).</li><li>Embon, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+dynamics+and+pinning+of+single+vortices+in+superconductors+at+nanometer+scales.">Probing dynamics and pinning of single vortices in superconductors at nanometer scales.</a> Sci. Rep. 5, 7598 (2015).</li><li>Auslaender, O. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanics+of+individual+isolated+vortices+in+a+cuprate+superconductor.">Mechanics of individual isolated vortices in a cuprate superconductor.</a> Nature Phys. 5, 35-39 (2008).</li><li>Kalisky, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavior+of+vortices+near+twin+boundaries+in+underdoped+Ba(Fe1-xCox)2As2.">Behavior of vortices near twin boundaries in underdoped Ba(Fe1-xCox)2As2.</a> Phys. Rev. B. 83, 064511 (2011).</li><li>Huber, M. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gradiometric+micro-SQUID+susceptometer+for+scanning+measurements+of+mesoscopic+samples.">Gradiometric micro-SQUID susceptometer for scanning measurements of mesoscopic samples.</a> Rev. Sci. Instrum. 79, 053704 (2008).</li><li>Koshnick, N. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+terraced+scanning+super+conducting+quantum+interference+device+susceptometer+with+submicron+pickup+loops.">A terraced scanning super conducting quantum interference device susceptometer with submicron pickup loops.</a> Appl. Phys. Lett. 93, 243101 (2008).</li><li>Kremen, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+Control+of+Individual+Superconducting+Vortices.">Mechanical Control of Individual Superconducting Vortices.</a> Nano Lett. 16, 1626-1630 (2016).</li></ol>

The authors have nothing to disclose.

vortices Başarılı manipülasyon birçok kritik adımlar bağlıdır. Çip ucu numunesi ile temas kurmaya ilk olacak şekilde, bir açıyla sensörü hizalamak için önemlidir. İkinci olarak, örnek üzerine uygulanan kuvvet çip monte edilir konsol mekanik özellikleri ile belirlenir dikkat etmek önemlidir. Elastik rejimde, uygulanan kuvvet Hooke yasasına göre, saptırma, x orantılıdır: F = -kx Burada K malzemenin Young modülü ve fiziksel boyutları tarafından belirlenen...

Girdaplar dış manyetik alanın varlığında tip 2 Süperiletkenlerde oluşan nano manyetik nesneler vardır. Bir kusur ücretsiz örneğinde, girdaplar serbestçe hareket edebilir. Ancak, girdapların için enerjik elverişli azaltılmış süperiletkenlik bölgelerinde maddi sonuç farklı kusurlar. Girdaplar bu bölgeleri, aynı zamanda çivileme siteleri olarak bilinen dekore eğilimindedir. Bu durumda, bir girdap hareket ettirmek için gerekli olan kuvvet sabitleme kuvvetinden daha büyük olması gerekmektedir. Bu girdap yoğunluğu, etkileşim gücü ve aralık gibi girdapların, özellikleri, kolayca dış alanı, sıcaklık, ya da numune geometrisi ile belirlenebilir. Bu özellikleri kontrol etme yeteneği, onları, elektronik uygulamaları 1, 2, kolayca ayarlanabilir yoğun madde davranışı, hem de müsait adaylar için iyi bir model sistemi sağlar. Bireysel vortices yerini kontrolü, lo tasarımı için gerekli olanrahi elemanları. Manyetik nanopartiküller mekanik kontrolü daha önce elde edilmişti. Kalisky ve diğ. Son zamanlarda kompleks oksit arayüzleri 3 ferromanyetik yamalar yerel mekanik stres etkisini incelemek için tarama süperiletken kuantum girişim cihazı (SQUID) kullanılır. Onlar süreçte kadar 1 μN bir güç uygulayarak, numunenin içine SQUID ucu basarak temas tarayarak yama yönünü değiştirmek için başardık. Biz girdapları taşımak için bizim protokolde benzer bir yöntem kullandık. Girdap manipülasyon Mevcut çalışmalarda, hareket ve böylece Lorentz kuvveti 4, 5, 6 oluşturma, numune akımı uygulanarak elde edildi. bu yöntem etkili olsa da, yerel değildir ve tek bir girdap kontrol etmek amacıyla, ek bir üretim gereklidir. Girdaplar da Manip olabilirmanyetik kuvvet mikroskopu (MFM) veya kalamar alan sargısı 7, 8, örneğin, harici bir manyetik alan uygulayarak ile düzenlenmiştir. Bu yöntem etkili ve yerel, ama bu araçlar tarafından uygulanan kuvvet küçük ve sadece süperiletken kritik sıcaklığına yakın yüksek sıcaklıklarda çivileme kuvvetini üstesinden gelebilir. Bizim protokol örneğinin ek imalat olmaksızın düşük sıcaklıklarda (4 K) etkili, yerel müdahale etmenizi sağlar. Biz tarama KALAMAR mikroskopi kullanılarak görüntü girdapları. Sensör bir köşeye cilalı ve esnek bir konsol üzerinde yapıştırılmış bir silikon çip üzerinde imal edilir. Konsol yüzeyinin kapasitif algılama için kullanılır. temas noktası çip ucunda, böylece çip, örnek bir açı ile yerleştirilir. Bu numune içine çip iterek kadar 2 μN kuvvetleri uygulanır. Biz piezo elemanları tarafından SQUID örnek göreli hareket ettirin. Biz hareketBir girdaba yanında, ya da onu süpürme girdap dokunarak silikon ucu dokunarak girdap.

<table><tbody><tr><td>stick slip coarse motion system</td><td>attocube</td><td>ANPx-101</td><td>x,y motion</td></tr><tr><td>stick slip coarse motion system</td><td>attocube</td><td>ANPz-101</td><td>z motion</td></tr><tr><td>stick slip coarse motion system controller</td><td>Attocube</td><td>ANC 300</td><td></td></tr><tr><td>high voltage amplifier</td><td>Attocube</td><td>ANC 250</td><td></td></tr><tr><td>data acquisition card</td><td>National Instruments</td><td>NI&amp;nbsp;PCIe-6363</td><td></td></tr><tr><td>piezo elements</td><td>Piezo Systems Inc</td><td>T2C</td><td>non magnetic</td></tr><tr><td>low noise voltage preamplifier</td><td>Stanford Research Systems</td><td>SR 560</td><td></td></tr><tr><td>capacitance bridge</td><td>General Radio</td><td>1615A</td><td></td></tr><tr><td>telescope</td><td>NAVITAR</td><td>1-504516</td><td></td></tr><tr><td>camera</td><td>MOTICAM</td><td>MP2</td><td></td></tr><tr><td>dewar</td><td>Cryofab</td><td>N/A</td><td></td></tr><tr><td>insert</td><td>ICE oxford</td><td>N/A</td><td></td></tr><tr><td>Mu-metal shield</td><td>Amuneal</td><td>N/A</td><td></td></tr><tr><td>vacuum cap</td><td>ICE oxford</td><td>N/A</td><td></td></tr><tr><td>sputtering system</td><td>AJA international Inc</td><td>N/A</td><td></td></tr><tr><td>lapping film</td><td>3M</td><td>261X</td><td>non magnetic</td></tr><tr><td>Nb target</td><td>Kurt J. Lesker</td><td>EJTNBXX351A2</td><td></td></tr><tr><td>GE Varnish</td><td>CMR-Direct</td><td>02-33-001</td><td>for cryogenic heatsinking</td></tr><tr><td>Silver paste</td><td>Structure Probe Inc</td><td>05063-AB</td><td></td></tr></tbody></table>

scanning squid study of vortex manipulation by local contact

Local, deterministic manipulation of individual vortices in type 2 superconductors is challenging. The ability to control the position of individual vortices is necessary in order to study how vortices interact with each other, with the lattice, and with other magnetic objects. Here, we present a protocol for vortex manipulation in thin superconducting films by local contact, without applying current or magnetic field. Vortices are imaged using a scanning superconducting quantum interference device (SQUID), and vertical stress is applied to the sample by pushing the tip of a silicon chip into the sample, using a piezoelectric element. Vortices are moved by tapping the sample or sweeping it with the silicon tip. Our method allows for effective manipulation of individual vortices, without damaging the film or affecting its topography. We demonstrate how vortices were relocated to distances of up to 0.8 mm. The vortices remained stable at their new location up to five days. With this method, we can control vortices and move them to form complex configurations. This technique for vortex manipulation could also be implemented in applications such as vortex based logic devices.

Bizim protokolü başarılı bir şekilde Nb, iki numune ve NBN dokuz numunelerdeki tek tek, iyi ayrılmış girdapların bin üzerinde test edilmiştir. Tc Yukarıdaki örnek ısıtılması, ve manyetik alanın varlığında Lütfen 4.2 K soğutmak suretiyle aynı numune üzerinde yeni girdapları oluştururlar. Biz arzu girdap yoğunluğu elde etmek için dış manyetik alan seçti. Biz burada bu deneylerden gelen verileri göstermektedir. Bu sonuçlar, Kremen ve arkadaşları...

Watch this Scientific Journal Video about Scanning SQUID Study of Vortex Manipulation by Local Contact at JoVE.com

Scanning SQUID Study of Vortex Manipulation by Local Contact

We present a protocol for manipulation of individual vortices in thin superconducting films, using local mechanical contact. The method does not include applying current, magnetic field or additional fabrication steps.

Yerel İletişim tarafından Vortex Manipülasyon KALAMAR Çalışması taranması

Local, deterministic manipulation of individual vortices in type 2 superconductors is challenging. The ability to control the position of individual ...

scanning-squid-study-of-vortex-manipulation-by-local-contact

Research

JoVE Journal

Engineering

6.8K Görüntüleme.  Bar-Ilan University. We present a protocol for manipulation of individual vortices in thin superconducting films, using local mechanical contact. The method does not include applying current, magnetic field or additional fabrication steps. 

Video: Scanning SQUID Study of Vortex Manipulation by Local Contact

Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus (SCUVA)

The ability to directly measure velocity fields in a fluid environment is necessary to provide empirical data for studies in fields as diverse as oceanography, ecology, biology, and fluid mechanics. Field measurements introduce practical challenges such as environmental conditions, animal availability, and the need for field-compatible measurement techniques. To avoid these challenges, scientists typically use controlled laboratory environments to study animal-fluid interactions. However, it is reasonable to question whether one can extrapolate natural behavior (i.e., that which occurs in the field) from laboratory measurements. Therefore, in situ quantitative flow measurements are needed to accurately describe animal swimming in their natural environment.
We designed a self-contained, portable device that operates independent of any connection to the surface, and can provide quantitative measurements of the flow field surrounding an animal. This apparatus, a self-contained underwater velocimetry apparatus (SCUVA), can be operated by a single scuba diver in depths up to 40 m. Due to the added complexity inherent of field conditions, additional considerations and preparation are required when compared to laboratory measurements. These considerations include, but are not limited to, operator motion, predicting position of swimming targets, available natural suspended particulate, and orientation of SCUVA relative to the flow of interest. The following protocol is intended to address these common field challenges and to maximize measurement success.

Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus SCUVA

This protocol provides instructions on how to use a self-contained underwater velocimetry apparatus (SCUVA), which is designed for quantification of in situ animal-generated flows. In addition, this protocol addresses challenges posed by field conditions, and includes operator motion, predicting position of animals, and orientation of SCUVA.

Kantitatif Ölçüm In situ</emBağımsız Sualtı velosimetri Aparatı (SCUVA)> Akımlar

The ability to directly measure velocity fields in a fluid environment is necessary to provide empirical data for studies in fields as diverse as ...

Biyomühendislik

Quantitative and Qualitative Examination of Particle-particle Interactions Using Colloidal Probe Nanoscopy

Colloidal Probe Nanoscopy (CPN), the study of the nano-scale interactive forces between a specifically prepared colloidal probe and any chosen substrate using the Atomic Force Microscope (AFM), can provide key insights into physical interactions present within colloidal systems. Colloidal systems are widely existent in several applications including, pharmaceuticals, foods, paints, paper, soil and minerals, detergents, printing and much more.1-3 Furthermore, colloids can exist in many states such as emulsions, foams and suspensions. Using colloidal probe nanoscopy one can obtain key information on the adhesive properties, binding energies and even gain insight into the physical stability and coagulation kinetics of the colloids present within. Additionally, colloidal probe nanoscopy can be used with biological cells to aid in drug discovery and formulation development. In this paper we describe a method for conducting colloidal probe nanoscopy, discuss key factors that are important to consider during the measurement, and show that both quantitative and qualitative data that can be obtained from such measurements.

Colloidal probe nanoscopy can be used within a variety of fields to gain insight into the physical stability and coagulation kinetics of colloidal systems and aid in drug discovery and formulation sciences using biological systems. The method described within provides a quantitative and qualitative means to study such systems.

Kolloidal Probe Nanoscopy kullanarak parçacık-parçacık Etkileşimleri Nicel ve Nitel Sınav

Colloidal Probe Nanoscopy (CPN), the study of the nano-scale interactive forces between a specifically prepared colloidal probe and any chosen substrate ...

Kimya

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.

Oryantasyon ve dönme hızının ölçülmesi yöntemleri türbülansına tanecikler 3D basılmış

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

Mühendislik

Hand Controlled Manipulation of Single Molecules via a Scanning Probe Microscope with a 3D Virtual Reality Interface

Considering organic molecules as the functional building blocks of future nanoscale technology, the question of how to arrange and assemble such building blocks in a bottom-up approach is still open. The scanning probe microscope (SPM) could be a tool of choice; however, SPM-based manipulation was until recently limited to two dimensions (2D). Binding the SPM tip to a molecule at a well-defined position opens an opportunity of controlled manipulation in 3D space. Unfortunately, 3D manipulation is largely incompatible with the typical 2D-paradigm of viewing and generating SPM data on a computer. For intuitive and efficient manipulation we therefore couple a low-temperature non-contact atomic force/scanning tunneling microscope (LT NC-AFM/STM) to a motion capture system and fully immersive virtual reality goggles. This setup permits &#34;hand controlled manipulation&#34; (HCM), in which the SPM tip is moved according to the motion of the experimenter&#39;s hand, while the tip trajectories as well as the response of the SPM junction are visualized in 3D. HCM paves the way to the development of complex manipulation protocols, potentially leading to a better fundamental understanding of nanoscale interactions acting between molecules on surfaces. Here we describe the setup and the steps needed to achieve successful hand-controlled molecular manipulation within the virtual reality environment.

We demonstrate the precise manipulation of individual organic molecules on a metal surface with the tip of a scanning probe microscope driven in 3D by the experimenter's hand using a motion capture system and fully immersive virtual reality goggles.

El 3D Sanal Gerçeklik Arayüzü ile bir Tarama Prob Mikroskobu üzerinden Tek Moleküllerin Manipülasyon Kontrollü

Considering organic molecules as the functional building blocks of future nanoscale technology, the question of how to arrange and assemble such building ...

Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp

The fluid-structure energy exchange process for normal speech has been studied extensively, but it is not well understood for pathological conditions. Polyps and nodules, which are geometric abnormalities that form on the medial surface of the vocal folds, can disrupt vocal fold dynamics and thus can have devastating consequences on a patient&#39;s ability to communicate. Our laboratory has reported particle image velocimetry (PIV) measurements, within an investigation of a model polyp located on the medial surface of an in&#160;vitro driven vocal fold model, which show that such a geometric abnormality considerably disrupts the glottal jet behavior. This flow field adjustment is a likely reason for the severe degradation of the vocal quality in patients with polyps. A more complete understanding of the formation and propagation of vortical structures from a geometric protuberance, such as a vocal fold polyp, and the resulting influence on the aerodynamic loadings that drive the vocal fold dynamics, is necessary for advancing the treatment of this pathological condition. The present investigation concerns the three-dimensional flow separation induced by a wall-mounted prolate hemispheroid with a 2:1 aspect ratio in cross flow, i.e. a model vocal fold polyp, using an oil-film visualization technique. Unsteady, three-dimensional flow separation and its impact of the wall pressure loading are examined using skin friction line visualization and wall pressure measurements.

Vocal fold polyps can disrupt vocal fold dynamics and thus can have devastating consequences on a patient&#39;s ability to communicate. Three-dimensional flow separation induced by a wall-mounted model polyp and its impact on the wall pressure loading are examined using particle image velocimetry, skin friction line visualization, and wall pressure measurements.

Model Vocal Fold Polip'in Neden Olduğu Üç Boyutlu Akış Ayrımının Araştırılması

The fluid-structure energy exchange process for normal speech has been studied extensively, but it is not well understood for pathological conditions. ...

Visualization of Flow Field Around a Vibrating Pipeline Within an Equilibrium Scour Hole

An experimental method is presented in this paper to facilitate visualization of the detailed flow fields and determination of the near-boundary shear and normal stresses within an equilibrium scour hole induced by a vibrating pipeline. This method involves the implementation of a pipeline vibration system in a straight flume, a time-resolved particle image velocimetry (PIV) system for pipeline displacement tracking and flow fields measurements. The displacement time-series of the vibrating pipeline are obtained by using the cross-correlation algorithms. The steps for processing raw particle laden images obtained by using the time-resolved PIV are described. The detailed instantaneous flow fields around the vibrating pipeline at different vibrating phases are calculated by using a multiple-time-interval cross-correlation algorithm to avoid displacement bias error in the flow regions with a large velocity gradient. By applying the wavelet transform technique, the captured images that have the same vibrating phase are accurately cataloged before the phase-averaged velocity fields are obtained. The key advantages of the flow measurement technique described in this paper are that it has a very high temporal and spatial resolution and can be simultaneously used to obtain the pipeline dynamics, flow fields, and near-boundary flow stresses. By using this technique, more in-depth studies of the 2-dimensional flow field in a complex environment, such as that around a vibrating pipeline, can be conducted to better understand the associated sophisticated scour mechanism.

The goal of the protocol is to enable visualization of the detailed flow fields and determination of the near-boundary shear and normal stresses within an equilibrium scour hole induced by a vibrating pipeline.

Bir Denge Scour Hole Içinde Titreşimli Boru Hattı Etrafında Akış Alanı Görselleştirme

An experimental method is presented in this paper to facilitate visualization of the detailed flow fields and determination of the near-boundary shear and ...

Çevre

Fabrication of Magnetic Nanostructures on Silicon Nitride Membranes for Magnetic Vortex Studies Using Transmission Microscopy Techniques

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared on transparent membranes which are very fragile and difficult to manipulate. We present processes for the fabrication of samples with magnetic micro- and nanostructures with spin configurations forming magnetic vortices suitable for Lorentz transmission electron microscopy and magnetic transmission x-ray microscopy studies. The samples are prepared on silicon nitride membranes and the fabrication consists of a spin coating, UV and electron-beam lithography, the chemical development of the resist, and the evaporation of the magnetic material followed by a lift-off process forming the final magnetic structures. The samples for the Lorentz transmission electron microscopy consist of magnetic nanodiscs prepared in a single lithography step. The samples for the magnetic x-ray transmission microscopy are used for time-resolved magnetization dynamic experiments, and magnetic nanodiscs are placed on a waveguide which is used for the generation of repeatable magnetic field pulses by passing an electric current through the waveguide. The waveguide is created in an extra lithography step.

A protocol for the fabrication of magnetic micro- and nanostructures with spin configurations forming magnetic vortices suitable for transmission electron microscopy (TEM) and magnetic transmission x-ray microscopy (MTXM) studies is presented.

Silikon nitrür membranlar üzerinde manyetik nanoyapıları imalatı transmisyon mikroskopisi teknikleri kullanarak manyetik girdap etütler

Electron and x-ray magnetic microscopies allow for high-resolution magnetic imaging down to tens of nanometers. However, the samples need to be prepared ...

Direct Force Measurements of Subcellular Mechanics in Confinement using Optical Tweezers

During the development of a multicellular organism, a single fertilized cell divides and gives rise to multiple tissues with diverse functions. Tissue morphogenesis goes in hand with molecular and structural changes at the single cell level that result in variations of subcellular mechanical properties. As a consequence, even within the same cell, different organelles and compartments resist differently to mechanical stresses; and mechanotransduction pathways can actively regulate their mechanical properties. The ability of a cell to adapt to the microenvironment of the tissue niche thus is in part due to the ability to sense and respond to mechanical stresses. We recently proposed a new mechanosensation paradigm in which nuclear deformation and positioning enables a cell to gauge the physical 3D environment and endows the cell with a sense of proprioception to decode changes in cell shape. In this article, we describe a new method to measure the forces and material properties that shape the cell nucleus inside living cells, exemplified on adherent cells and mechanically confined cells. The measurements can be performed non-invasively with optical traps inside cells, and the forces are directly accessible through calibration-free detection of light momentum. This allows measuring the mechanics of the nucleus independently from cell surface deformations and allowing dissection of exteroceptive and interoceptive mechanotransduction pathways. Importantly, the trapping experiment can be combined with optical microscopy to investigate the cellular response and subcellular dynamics using fluorescence imaging of the cytoskeleton, calcium ions, or nuclear morphology. The presented method is straightforward to apply, compatible with commercial solutions for force measurements, and can easily be extended to investigate the mechanics of other subcellular compartments, e.g., mitochondria, stress-fibers, and endosomes.

Here, we present a protocol to investigate the intracellular mechanical properties of isolated embryonic zebrafish cells in three-dimensional confinement with direct force measurement by an optical trap.

Optik Cımbız Kullanarak Hapsetmede Hücre Altı Mekaniğinin Doğrudan Kuvvet Ölçümleri

During the development of a multicellular organism, a single fertilized cell divides and gives rise to multiple tissues with diverse functions. Tissue ...

Gelişim Biyolojisi

Using a Microfluidics Device for Mechanical Stimulation and High Resolution Imaging of C. elegans

One central goal of mechanobiology is to understand the reciprocal effect of mechanical stress on proteins and cells. Despite its importance, the influence of mechanical stress on cellular function is still poorly understood. In part, this knowledge gap exists because few tools enable simultaneous deformation of tissue and cells, imaging of cellular activity in live animals, and efficient restriction of motility in otherwise highly mobile model organisms, such as the nematode Caenorhabditis elegans. The small size of C. elegans makes them an excellent match to microfluidics-based research devices, and solutions for immobilization have been presented using microfluidic devices. Although these devices allow for high-resolution imaging, the animal is fully encased in polydimethylsiloxane (PDMS) and glass, limiting physical access for delivery of mechanical force or electrophysiological recordings. Recently, we created a device that integrates pneumatic actuators with a trapping design that is compatible with high-resolution fluorescence microscopy. The actuation channel is separated from the worm-trapping channel by a thin PDMS diaphragm. This diaphragm is deflected into the side of a worm by applying pressure from an external source. The device can target individual mechanosensitive neurons. The activation of these neurons is imaged at high-resolution with genetically-encoded calcium indicators. This article presents the general method using C. elegans strains expressing calcium-sensitive activity indicator (GCaMP6s) in their touch receptor neurons (TRNs). The method, however, is not limited to TRNs nor to calcium sensors as a probe, but can be expanded to other mechanically-sensitive cells or sensors.

Using a Microfluidics Device for Mechanical Stimulation and High Resolution Imaging of C. elegans

New tools for mechanobiology research are needed to understand how mechanical stress activates biochemical pathways and elicits biological responses. Here, we showcase a new method for selective mechanical stimulation of immobilized animals with a microfluidic trap allowing high-resolution imaging of cellular responses.

Mekanik stimülasyon ve yüksek çözünürlük görüntüleme C. elegans bir havacilik aygıtı kullanma

One central goal of mechanobiology is to understand the reciprocal effect of mechanical stress on proteins and cells. Despite its importance, the ...

Nörobilim

Visualizing Membrane Ruffle Formation using Scanning Electron Microscopy

Membrane ruffling is the formation of motile plasma membrane protrusions containing a meshwork of newly polymerized actin filaments. Membrane ruffles may form spontaneously or in response to growth factors, inflammatory cytokines, and phorbol esters. Some of the membrane protrusions may reorganize into circular membrane ruffles that fuse at their distal margins and form cups that close and separate into the cytoplasm as large, heterogeneous vacuoles called macropinosomes. During the process, ruffles trap extracellular fluid and solutes that internalize within macropinosomes. High-resolution scanning electron microscopy (SEM) is a commonly used imaging technique to visualize and quantify membrane ruffle formation, circular protrusions, and closed macropinocytic cups on the cell surface. The following protocol describes the cell culture conditions, stimulation of the membrane ruffle formation in vitro, and how to fix, dehydrate, and prepare cells for imaging using SEM. Quantification of membrane ruffling, data normalization, and stimulators and inhibitors of membrane ruffle formation are also described. This method can help answer key questions about the role of macropinocytosis in physiological and pathological processes, investigate new targets that regulate membrane ruffle formation, and identify yet uncharacterized physiological stimulators as well as novel pharmacological inhibitors of macropinocytosis.

Macropinocytosis is a highly conserved endocytic process initiated by the formation of F-actin-rich sheet-like membrane projections, also known as membrane ruffles. Increased rate of macropinocytotic solute internalization has been implicated in various pathological conditions. This protocol presents a method to quantify membrane ruffle formation in vitro using scanning electron microscopy.

Taramalı Elektron Mikroskobu ile Membran Fırfırı Oluşumunu Görselleştirme

Membrane ruffling is the formation of motile plasma membrane protrusions containing a meshwork of newly polymerized actin filaments. Membrane ruffles may ...