Search results for "Microscopy"
showing 10 items of 3390 documents
Thermal noise limit for ultra-high vacuum noncontact atomic force microscopy
2013
The noise of the frequency-shift signal Δf in noncontact atomic force microscopy (NC-AFM) consists of cantilever thermal noise, tip–surface-interaction noise and instrumental noise from the detection and signal processing systems. We investigate how the displacement-noise spectral density dz at the input of the frequency demodulator propagates to the frequency-shift-noise spectral density dΔf at the demodulator output in dependence of cantilever properties and settings of the signal processing electronics in the limit of a negligible tip–surface interaction and a measurement under ultrahigh-vacuum conditions. For a quantification of the noise figures, we calibrate the cantilever displacemen…
Modification of a commercial atomic force microscopy for low-noise, high-resolution frequency-modulation imaging in liquid environment.
2011
A key issue for high-resolution frequency-modulation atomic force microscopy imaging in liquids is minimizing the frequency noise, which requires a detailed analysis of the corresponding noise contributions. In this paper, we present a detailed description for modifying a commercial atomic force microscope (Bruker MultiMode V with Nanoscope V controller), aiming at atomic-resolution frequency-modulation imaging in ambient and in liquid environment. Care was taken to maintain the AFMs original stability and ease of operation. The new system builds upon an optimized light source, a new photodiode and an entirely new amplifier. Moreover, we introduce a home-built liquid cell and sample holder …
Direct Visualization of Molecule Deprotonation on an Insulating Surface
2012
Elucidating molecular-scale details of basic reaction steps on surfaces is decisive for a fundamental understanding of molecular reactivity within many fields, including catalysis and on-surface synthesis. Here, the deprotonation of 2,5-dihydroxybenzoic acid (DHBA) deposited onto calcite (101;4) held at room temperature is followed in situ by noncontact atomic force microscopy. After deposition, the molecules form two coexisting phases, a transient striped phase and a stable dense phase. A detailed analysis of high-resolution noncontact atomic force microscopy images indicates the transient striped phase being a bulk-like phase, which requires hydrogen bonds between the carboxylic acid moie…
New advances in high-resolution optical microscopy
2015
La microscopio ía tiene como nalidad observar muestras que no pueden distinguirse a simple vista por el ojo humano dado que el tamaño de ellas es menor que su l mite de resoluci on. Un microscopio produce una imagen ampliada de la muestra a analizar. Debido a que la microscopía es un instrumento b asico para la ciencia de la vida y de los materiales, en esta Tesis se desarrolla un estudio exhaustivo de la microscopía óptica. Los microscopios opticos se pueden con gurar de diferentes formas para producir im agenes con diferentes caracter sticas. El microscopio de campo amplio, el m as simple de todos, presenta algunas limitaciones que debe ser superadas para obtener im agenes de mayor calida…
Structural and optical characterization of ZnS ultrathin films prepared by low-temperature ALD from diethylzinc and 1.5-pentanedithiol after various …
2019
The structural and optical evolution of the ZnS thin films prepared by atomic layer deposition (ALD) from the diethylzinc (DEZ) and 1,5-pentanedithiol (PDT) as zinc and sulfur precursors was studied. A deposited ZnS layer (of about 60 nm) is amorphous, with a significant S excess. After annealing, the stoichiometry improved for annealing temperatures &ge
Synthesis, Optical, and Morphological Studies of ZnO Powders and Thin Films Fabricated by Wet Chemical Methods
2020
Zinc oxide nanoparticles were prepared from Zn5(CO3)2(OH)6 precursor, capped with poly(vinylpyrrolidone) (PVP), and annealed at 600 °
Optical and structural properties of Al 2 O 3 /ZnO nanolaminates deposited by ALD method
2014
International audience; We report on the investigation of optical and structural properties of Al2O3/ZnO nanolaminates. The nanolaminates were deposited on Si and glass substrates by Atomic layer deposition method. Structural properties of nanolaminates were studied by SEM, GIXRD, and AFM. Optical characterization was performed by transmittance and photoluminescence spectroscopy. Complex analysis of monolayer properties was done by ellipsometry. Optical constants for Al2O3 and ZnO monolayer were calculated.
Morphology and composition of particulate matter in the air of urban area
2019
Zanieczyszczenie powietrza przez pyl zawieszony (PM) staje się w ostatnich latach coraz bardziej znaczące. Stwierdzono, że unoszące się w powietrzu cząsteczki niosą różne niekorzystne skutki dla środowiska i zdrowia ludzkiego. Aby poszerzyć wiedzę na temat takich zanieczyszczeń, pożądana jest szczegółowa charakterystyka rozmiarów, morfologii i składu chemicznego poszczególnych cząstek zawieszonych w po- wietrzu. W prezentowanych badaniach mikrocząsteczki powietrza zostały pobrane z filtrów taśmowych z włókna szklanego, które są powszechnie stosowane w analizatorach cząstek stałych MP101M. Próbki zostały zebrane w Kutnej Horze (Republika Czeska), były badane metodami skaningowej mikroskopii …
Surfactant-Mediated Morphology and Photocatalytic Activity of α‑Ag2WO4 Material
2018
In the present work, the morphology (hexagonal rod-like vs cuboid-like) of an α-Ag2WO4 solid-state material is manipulated by a simple controlled-precipitation method, with and without the presence of the anionic surfactant sodium dodecyl sulfate (SDS), respectively, over short reaction times. Characterization techniques, such as X-ray diffraction analysis, Rietveld refinement analysis, Fourier-transform (FT) infrared spectroscopy, FT Raman spectroscopy, UV–vis spectroscopy, transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive X-ray spectroscopy, field emission-scanning electron microscopy (FE-SEM), and photoluminescence emission…
TRAIL acts synergistically with iron oxide nanocluster-mediated magneto- and photothermia
2019
International audience; Targeting TRAIL (Tumor necrosis factor (TNF)-Related Apoptosis-Inducing Ligand) receptors for cancer therapy remains challenging due to tumor cell resistance and poor preparations of TRAIL or its derivatives. Herein, to optimize its therapeutic use, TRAIL was grafted onto iron oxide nanoclusters (NCs) with the aim of increasing its pro-apoptotic potential through nanoparticle-mediated magnetic hyperthermia (MHT) or photothermia (PT). Methods: The nanovector, NC@TRAIL, was characterized in terms of size, grafting efficiency, and potential for MHT and PT. The therapeutic function was assessed on a TRAIL-resistant breast cancer cell line, MDA-MB-231, wild type (WT) or T…