06. 2010 IMSAloquium Student Investigation Showcase

https://digitalcommons.imsa.edu/class_of_2010/1004/thumbnail.jp

2010 IMSAloquium, Student Investigation Showcase

IMSA students engage in investigations in nanotechnology, particle physics, law, neonatal medicine, literature, transplantation biology, water purity, the educational achievement gap, neurobiology and memory, ethics, theatre, discrete mathematics, economics, and more.https://digitalcommons.imsa.edu/archives_sir/1002/thumbnail.jp

Ti3C2 MXene–polymer nanocomposites and their applications

MXene/polymer nanocomposites simultaneously benefit from the attractive properties of MXenes and the flexibility and facile processability of polymers. These composites have shown superior properties such as high light-to-heat conversion, excellent electromagnetic interference shielding, and high charge storage, compared to other nanocomposites. They have applications in chemical, materials, electrical, environmental, mechanical, and biomedical engineering as well as medicine. This property-based review on MXene/polymer nanocomposites critically describes findings and achievements in these areas and puts future research directions into perspective. It surveys novel reported applications of MXene-based polymeric nanocomposites. It also covers surface modification approaches that expand the applications of MXenes in nanocomposites

2nd International Conference on Nanomaterials Science and Mechanical Engineering: book of abstracts

2nd International Conference on Nanomaterials Science and Mechanical Engineering: book of abstracts - University of Aveiro, Portugal July 9-12, 2019.publishe

Metal oksitler ile modifiye edilmiş karbon türevlerinden nanokompozit yapıların sentezi ve karakterizasyonu

xi, 106 sayfa29 cm. 1 CDÖzet:Disiplinler arası bir yaklaşıma sahip olan nanobilim ve nanoteknoloji son yıllarda modern dünyayı etkili bir şekilde dönüştürüp, biçimlendirmeye başlamıştır. Teoride birbirine uzak temellere dayanan bilim alanlarının temsilcileri nanobilim çatısı altında bir araya gelerek yenilikçi, çevreci ve hayatı kolaylaştıran teknolojiler geliştirmektedir. Bu gün bu teknolojik ürünler akıllı malzemeler olarak anılır. Yeni nesil nanokompozitler de eşsiz özelliklerinden dolayı akıllı malzeme olarak kabul edilmektedir. Bu çalışmada metal oksitler ile modifiye edilmiş karbon türevlerinden nanokompozitler sentezlenmiş ve bu yapıların yüzey analiz karakterizasyonları, taramalı elektron mikroskobu(SEM), Raman spektroskopisi (RAMAN) ve X-ışını difraktometrisi(XRD) ile yapılmıştır.Summary:Nanoscience and nanotechnology, which have an interdisciplinary approach, have begun to effectively transform and shape the modern world in recent years. In theory, representatives of science fields based on distant foundations come together in the field of nanoscience to develop innovative, environmentally friendly and life-facilitating technologies. Today, these technological products are referred to as smart materials. New generation nanocomposites are also considered as smart materials due to their unique properties. In this study, nanocomposites from carbon derivatives modified with metal oxides were synthesized and surface analysis characterizations of these structures were done by scanning electron microscopy (SEM), Raman spectroscopy (RAMAN) and X-ray diffractometry (XRD)

Structural and electrical characterization of doped graphene and carbon nanotube networks

Graphene, a two-dimensional sp2-hybridized network of carbon atoms has received a remarkable cornucopia of new physics and served as a unique model system, due particularly to its electronic properties, which could have interesting applications in electronic, spintronic or quantum devices. The first part of the thesis describes the modulation of graphene¿s structural and electrical properties with various kinds of doping; such as deep ultraviolet irradiation in ambient atmosphere, deep ultraviolet light irradiation in different gaseous environments, and electron beam irradiation. We have fabricated graphene (exfoliated and chemical vapor deposition grown graphene) field effect transistors using photolithography and electron beam lithography and characterized with AFM, Raman spectroscopy and transport measurement using low noise standard lock-in amplifier technique. We have explored how the ultraviolet light exposure tunes the electrical properties of graphene in an ambient atmosphere, confirmed by the shift of Dirac point position towards positive gate voltage, revealing p-type doping for graphene without degradation of mobility. We found that the doping is stable for a time scale of months. This method became more useful when half the graphene device was exposed by ultraviolet light, while the other half part was covered by a mask to make a sharp p-n junction. The doping effect became more prominent and controllable when it was made in an oxygen environment. The most interesting phenomena were observed when doped graphene was restored to a pristine state using ultraviolet light irradiation in a nitrogen environment. Furthermore, we have investigated the doping tunability with ultraviolet light irradiation on mechanically exfoliated single-, bi-, and trilayer graphenes without significantly degrading its charge carrier mobility. In a further study, the structural deformation of graphene was investigated by irradiation of an electron beam. The graphene structure changes its phase in various stages, where graphene transforms gradually from a crystalline to a nanocrystalline form and after a certain irradiation time into an amorphous form. This irradiation effect acts as an n-type dopant for graphene. In this case, mobility decreases with the gradual increase of irradiation dose, which implies the formation of localized states. The second part of the thesis describes carbon nanotube networks as flexible and transparent electrodes for electronic devices, particularly for high frequency applications. The observed results show that at low frequencies, the impedance increases as the density of nanotube networks decreases, as expected. Both the real and imaginary parts of impedance (measured up to 20 GHz) abruptly decrease as the frequency increases over the cut-off frequency. The cut-off frequency not only depends on the carbon nanotube density of the network, but also on the sample geometry. The Nyquist diagram suggests a simple equivalent circuit composed of a parallel combination of a resistor and a capacitor. The experimental results are in line with calculations made by electrochemical spectroscopy simulations. The results show that the electrical behavior is mostly determined by the contact resistance between the nanotubes, which are in a completely disordered distribution in the network. We show that carbon nanotube flexible conducting films, which may be transparent, could be competitive for some applications, such as displays, photovoltaic solar cells or selective sensors.El grafè, considerat com una xarxa bidimensional d’àtoms de carboni units per enllaços híbrids sp2, és un tema de recerca molt prolífer en els últims anys, com a model de sòlid bidimensional, i molt particularment degut a les seves propietats electròniques, que poden tenir aplicacions interessants en dispositius electrònics, spintrònics o quàntics. La primera part de la Tesi descriu la modificació de les propietats estructurals i elèctriques del grafè utilitzant diferents mètodes per a dopar-lo: radiació ultraviolada d’alta energia (DUV) en atmosfera ambient, DUV en diferents gasos tals com oxigen o nitrogen, o irradiant amb un feix d’electrons (e-beam). Hem fabricat transistors d’efecte de camp (FET) amb grafè (exfoliat a partir del grafit, o bé obtingut per deposició química en fase vapor, CVD) utilitzant fotolitografia i e-beam litografia, i els hem caracteritzat mitjançant AFM, espectroscòpia Raman i mesures de transport elèctric, per a les que hem utilitzat la tècnica d’amplificació de baix soroll, el lock-in. Hem investigat com l’exposició a la llum ultraviolada en atmosfera ambient, modula les propietats elèctriques del grafè, de manera que la posició del punt de Dirac es desplaça cap a tensions de porta positives, cosa que implica dopatge de tipus-p, sense que hi hagi degradació de la mobilitat. El dopatge és estable al menys durant mesos. Amb el mateix mètode, quan només la meitat del dispositiu és exposat a la radiació ultraviolada mentre l’altre meitat és recobert per una màscara metàl·lica, hem obtingut una unió p-n. L’efecte de dopatge és més important i controlable, quan és fet en atmosfera d’oxigen. L’efecte més interessant que hem observat és la reversibilitat, quan el grafè dopat retorna al seu estat primitiu, en ser irradiat amb llum ultraviolada en atmosfera de nitrogen. També hem investigat el dopatge amb llum ultraviolada del grafè exfoliat mecànicament, de una, dues o tres capes, observant que es produeix sense una degradació significativa de la mobilitat dels portadors de càrrega. Posteriorment hem estudiat la deformació estructural del grafè quan és irradiat amb un feix d’electrons. Hem observat canvis estructurals en diferents etapes: el grafè evoluciona gradualment, a partir de la forma cristal·lina, cap a una fase d’estructura nanocristal·lina i finalment, després d’una certa dosi de irradiació, presenta una estructura amorfa. L’efecte d’ irradiar el grafè amb electrons actua com a dopant tipus-n, però en aquest cas la mobilitat decreix en incrementar la dosi, això implica que hi ha formació d’estats localitzats. La segona part de la Tesi tracta de capes primes de nanotubs de carboni, com a elèctrodes flexibles i transparents per a dispositius electrònics, en particular per aplicacions d’alta freqüència. Els resultats obtinguts mostren que, a baixes freqüències, la impedància augmenta en disminuir la densitat de nanotubs, tal com cal esperar. Tan la part real com la part imaginària de la impedància (mesurada fins a 20 GHz) decreixen abruptament en augmentar la freqüència més enllà de la freqüència de tall. La freqüència de tall no depèn únicament de la densitat de nanotubs en la capa, sinó també de la geometria de la mostra. El diagrama de Nyquist es pot interpretar amb un circuit equivalent consistent simplement en una resistència i un condensador en paral·lel. Els resultats experimentals s’ajusten bé a les simulacions fetes per espectroscòpia d’impedàncies (EIS). Els resultats posen en evidència que el comportament elèctric queda majoritàriament determinat per la resistència de contacte entre els nanotubs, que formen la xarxa amb una distribució totalment desordenada. Hem vist que capes primes de nanotubs de carboni conductores i flexibles, que poden ser també transparents, poden ser competitives en diferents aplicacions, com ara pantalles, cel·les solars fotovoltaiques o sensors selectiu

Using nanocoating technology to improve the protective properties of fabrics

Дипломну бакалаврську роботу присвячено нанесенню нанопокриттів на тканини, що потребують покращення їх механічних характеристик. Опрацьовано види наноструктур та проаналізовані методи створення нанопокриттів. Виявлені особливості вуглецевих тканин, їх унікальні властивості та проблеми, що виникають при їх експлуатації. Проведені експериментальні дослідження режимів роботи вакуумної насосної установки УВМ 74 ЛП 32. В результаті проведеного дослідження виявлено, що метод вакуумного напилення має ряд переваг над методом електронапилення і найголовніше він дозволяє зберегти абсорбційні властивості тканини. Цей метод не надає можливості працювати з великими об’ємами тканин, але створює перспективу для розширення кількості зразків.The bachelor's thesis is devoted to the application of nanocoatings on fabrics that require improvement of their mechanical characteristics. The types of nanostructures were studied and the methods of creating nanocoatings were analysed. The features of carbon fabrics, their unique properties and problems arising during their operation are revealed. Experimental studies of the operating modes of the vacuum pumping unit UVM 74 LP 32 were carried out. The study revealed that the vacuum sputtering method has a number of advantages over the electrodeposition method, and most importantly, it allows preserving the absorption properties of the fabric. This method does not provide an opportunity to work with large volumes of tissues, but it creates a prospect for expanding the number of samples

MC 2019 Berlin Microscopy Conference - Abstracts

Das Dokument enthält die Kurzfassungen der Beiträge aller Teilnehmer an der Mikroskopiekonferenz "MC 2019", die vom 01. bis 05.09.2019, in Berlin stattfand