bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural evolution of
Pt/CNF
nanocomposites as a part of fuel cell's gas‐diffusion electrodes
Authors: Zhigalina Victoria , Zhigalina Olga , Ponomarev Igor , Ponomarev Ivan , Razorenov Dmitriy , Skupov Kirill 
Published: December 2016

A search of new nanostructural materials (such as gas‐diffusion layers, electrodes, catalysts, membranes etc.) for a polybenzimidazole‐membrane fuel cell remains a crucial task nowadays. Reducing of noble metals content has become one of the most significant goals in development of fuel cells while a balanced union of electron and ion conductivity along with gas permeability and catalytic activity of electrodes serves as an essential condition of the hydrogen‐air fuel cell efficiency [1].
In this study carbon nanocomposites of nanofiber nonwoven mats, produced by electrospinning and decorated with Pt, after work inside membrane electrode assembly as gas‐diffusion cathode at 160‐180 °C were investigated by analytical TEM and STEM methods [2].

Initially a nanofiber surface is evenly covered with a thick layer of Pt nanoparticles of anisotropic elongated shape with a number of sub angstrom atomic steps on their surface (
Fig. 1a
). This type of defects plays an important part in platinum catalytic activity [2,3].

The investigations of such a nanocomposite after work as a gas‐diffusion cathode in a fuel cell revealed significant changes in the structure of the platinum layer. After several hours of work at a standard fuel cell working temperature (160 °C) the structure of metal nanoparticles changes slightly (
Fig. 1b
). Metal nanoparticles preserve their shape elongated in direction and specific distribution on fibers surface same as in initial nanocomposites. However, in this case platinum is covered with a thin amorphous layer. Some of the platinum nanocrystals demonstrate the signs of partial melting and a loss of initial acicular shape as well as the decrease of surface defects.

After several days of work at standard and high fuel cell working temperature (160‐180 °C) the structure of catalyst changes considerably (
Fig. 1c
) and can be observed as melted conglomerates of unspecified shape and size of 40‐100 microns (
Fig. 2
) with a cover of thin (5‐10 nm) amorphous layer.
Cryo‐Electron Tomography of Protein Nanocrystals
Authors: Toots Maert , Skoglund Ulf 
Published: December 2016

Knowing the structure of biological molecules plays a key role in understanding their function. To date there is no single structure determination method that would always work for every biological molecule. Instead there exists a plethora of complementary methods each with their specific advantages and disadvantages. Small but difficult to crystallize proteins have proven to be a particularly hard target for many of the conventional methods. However, proteins that do not crystallize to large well‐diffracting crystals, could still form tiny nanocrystals in many cases, which could be completely invisible under regular light microscope or mistaken for amorphous precipitate when inspecting a crystallization drop.
Using cryo‐electron tomography we demonstrate in this work that real space imaging can be successfully used for structural studies of proteins that have been crystallized to nanocrystals. In this proof of principle research we have used cryo‐electron tomography to image lysozyme (molecular weight 14 kDa) nanocrystals in the size range of 100 nm. We show that by exploiting crystallographic symmetry inherent in the tomogram and taking advantage of other possibilities provided by real space imaging we can achieve resolution in the range of 15Å.
To achieve this result we have used in‐house software for 3D reconstruction and subsequent refinement of the reconstruction using maximum entropy regularization algorithm together with contrast transfer function deconvolution. For processing crystalline data we have developed a toolkit for necessary 3D image processing tasks, such as peak detection, crystallographic lattice parameter search and refinement, and 3D image averaging and space group symmetrization.
Nano‐crystal tomography could become an established method in structural biology complementing the existing methods by firstly being applicable on small and difficult to crystallize proteins, but secondly on any general 3D reconstruction that includes crystallographically related parts. On top of studying one single averaged molecule, this method can also be used to analyze the nano‐crystal as a whole and study the distribution of disorder within the crystal.
Monitoring of Dynamic Live Brain Tumor Cells using
SICM
and its Future Applications
Authors: Myung‐Hoon Choi , Goo‐Eun Jung , Cho Yong‐Sung , Cho Sang‐Joon 
Published: December 2016

The high resolution monitoring of live cell membranes in physiological conditions has been the homework for centuries for biologists. Visualization and Understanding of cell membrane activities could give precious insight upon how cells interact with outer environment. Scanning ion conductance microscopy (SICM) can provide the surface morphology of biological soft materials in liquid directly. The SICM uses ionic current as feedback signal by detecting it through the nano‐size opening of glass pipette. The dedicated SICM operating mode called approach and retract scanning (ARS) makes SICM imaging stable in liquid environment. The SICM three‐dimensional topographical image is generated by composing the recorded height information at each pixels. The in‐liquid imaging capability without physical contact allows using SICM for various cell study topics in live status such as cell division, fusion, and other fundamental physiological phenomena.
In this study, we examined cell‐to‐cell interaction and cell's plasma membrane transformation. By imaging live brain tumor cell with SICM at the connective position between two cells, we successfully acquired the interactive morphological changes of cell's adhesion molecule at the edge in sequence. From the series of non‐invasive cell morphological images, acquired in three dimension, we also calculated and monitored the velocity of membrane transformation and membrane holes volume changes.
Electron beam‐induced etching of carbon nanotubes by environmental transmission electron microscope
Authors: Tomita Yuto , Yoshida Hideto , Takeda Seiji 
Published: December 2016

It is crucially needed to develop a novel process to cut and connect nanomaterials artificially for further progress in nanotechnology. Gas‐mediated electron beam‐induced etching (EBIE) is promising to carve nanomaterials via electron beam‐induced chemical reactions between the nanomaterials and precursor gases. In this study, we have investigated the EBIE process of multi‐walled carbon nanotubes (CNTs) in oxygen gas using environmental transmission electron microscopy (ETEM).
Commercially available multi‐walled CNTs (NanoIntegris Inc.) were supported on a Cu micro grid with a carbon supporting film of 3 mm in diameter. A grid with multi‐walled CNTs was fixed on a specimen holder and transferred to an ETEM (FEI Tecnai F20 equipped with an environmental‐cell [1]) operated at 200 kV. As a precursor gas for EBIE, oxygen gas (99.9999%) was introduced into the ETEM. To carry out the EBIE of multi‐walled CNTs, a focused electron beam (about 0.2 nm in diameter) was repeatedly scanned across multi‐walled CNTs in oxygen gas of 100 Pa at room temperature in scanning TEM (STEM) mode.

Figure 1 shows the EBIE process of a multi‐walled CNT in oxygen gas. A focused electron beam was scanned repeatedly along a white dotted line in Fig. 1(a) with the rate of 103 s
−1
. STEM images and TEM images of the multi‐walled CNT were recorded after every 62 scans. The electron dose was estimated and shown in each image in Fig. 1. As the electron dose increases, the multi‐walled CNT is etched gradually. Figures 1(b), 1(c), 1(f), and 1(g) clearly show that the etching proceeds from the outer walls to inner walls of the multi‐walled CNT. Finally, the multi‐walled CNT is cut completely along the scanning direction (Fig. 1(d), (h)). The cutting surface remains cylindrical. We confirmed that the areas that do not receive electron dose are not etched. On the other hand, multi‐walled CNTs cannot be cut in a vacuum even after receiving the electron dose much higher to cut in oxygen gas. The scanning areas in multi‐walled CNTs are amorphized. This means that both electron irradiation and oxygen gas are needed for EBIE of multi‐walled CNTs. Oxygen atoms from dissociation of oxygen molecules by electron irradiation [2] react with carbon atoms in multi‐walled CNTs to produce CO and/or CO
2
which desorb from the surface of multi‐walled CNTs. We have succeeded in cutting of multi‐walled CNTs at desired positions at room temperature by EBIE in ETEM.

In the presentation, we will show the dependence of EBIE of multi‐walled CNTs on the pressure of oxygen gas, accelerating voltage of electrons, and gas species. The mechanism of EBIE of multi‐walled CNTs will be discussed.
Diamond‐based
MOSFET
s
: Bandgap interface profiling by
STEM
‐
EELS
Authors: Piñero José , Araújo Daniel , Villar Pilar , Pernot Julien 
Published: December 2016

In the view of developing high performance metal‐oxide‐diamond field effect transistor (diamond MOSFET), recent reports presents different approach in the choice of the gate material and, in particular, on the dielectric layer [1‐2]. However, a nanometric analysis of the band levels is necessary to understand the electron dynamic across the MOS stack. Recently, STEM‐EELS have been revealed as reliable technique to estimate the bandgap of SiO
2
dielectric materials. Nevertheless, its applicability has been limited to SiN
x
materials.

To evaluate electron transitions near the bandgap energy in the EELS spectra, researchers have to overcome several experimental difficulties. Here, we evaluate the effect of Čerenkov radiation and volume plasmon‐related peaks in low‐loss range of EELS spectra. In this study, STEM‐EELS techniques are used to analyse the O‐terminated diamond/Al
2
O
3
interface (similarly to previous studies presented in SiO
2
by other authors [3]). Indeed, volume plasmons (VP) and Čerenkov (Ch) radiation contribution are evidenced in Fig.1, which also shows diamond‐related D1‐2 peaks and Al
2
O
3
‐related peak A1 however, in the Al layer, only plasmon‐related peaks are revealed. Probe position of the previously presented EELS spectra are shown in Fig.2, as numbered dots. Figure 2 shows 001‐BF TEM micrography of the diamond/Al
2
O
3
/Al layers. Inset of Fig.2 shows HREM micrography of the diamond/Al
2
O
3
interface, revealing variations in the crystalline quality of the low temperature (100ºC) ALD‐deposited Al
2
O
3
layer.

In this work, we present a methodology to evaluate the influence of the Čerenkov losses and plasmon‐related peaks in the low‐loss EELS spectra. In some cases, such peaks are shown to mask the interband‐related transition. Indeed, in such cases, Čerenkov‐related and plasmon‐related peaks have to be deconvoluted and removed, in order to accurately apply the linear‐fit method [3], which allows calculating the diamond/oxide bandgaps.
The previously described methodology allows determining the bandgap variations in the oxygen‐terminated diamond/oxide interfaces.
Quantitative and non‐destructive defect metrology for beyond Si semiconductors
Authors: Prokhodtseva Anna , Vystavel Tomas , Schulze Andreas , Caymax Matty 
Published: December 2016

Electron channeling contrast imaging (ECCI) is a powerful scanning electron microscopy (SEM) technique for the visualization and analysis of crystalline defects like dislocations and stacking faults. Distortion of the crystal lattice of a material due to the presence of such defects causes the variation of the backscattered electron intensity, allowing their visualization. ECCI has been demonstrated to be a fast and robust method for assessing the density and Burgers vector of different defect types in various materials with reliability comparable to that of transmission electron microscopy [1, 2]. However, in contrast to TEM, ECCI can be used for the non‐destructive investigation of large areas.

This fact makes the technique particularly interesting for the semiconductor industry, where defect metrology techniques for the non‐destructive analysis of (Si)Ge and III/V compounds with dislocation densities below 10
5
cm
‐2
, are crucial to support CMOS scaling beyond the 10nm node.

In order to analyze such lowly defective samples, areas exceeding about 200 x 200µm
2
in size need to be examined to ensure proper statistics. For this purpose we acquire a set of tiles that can be stitched into a single image, thereby leading to an image resolution allowing for the detection of single threading dislocations. The FEI software application MAPS, dedicated to the automated acquisition of high resolution images from large areas, is used to record a set of ECC images that are further processed and examined for the presence of defects. It is important to note that for proper ECC imaging (i.e. maximum channeling contrast at a defect site), the sample needs to be oriented close to the Bragg condition. This is facilitated by tilting and rotating the sample according to the electron channeling pattern (Fig. 1) acquired by scanning the sample at low magnification. The investigated area of the tilted specimen is maintained in focus during the acquisition through the interpolation of the settings. Imaging conditions such as accelerating voltage and beam current were fine‐tuned in advance using a sample with higher defect density (Fig. 2). A retractable below‐the‐lens backscatter electron (BSE) detector is used to record the individual ECC images.

Using the above described procedure we analyzed in detail the density and distribution of threading dislocations in blanket SiGe layers of different defect densities. Our results reveal that in case of dedicated strain relaxed buffer layers the surface appears basically defect free over several tens of micrometers, only locally one can observe individual defects and pile‐ups of threadings reaching the layer surface. Results are verified by defect decoration using chemical etching followed by optical etch pit detection.
Our work demonstrates that ECCI in combination with automated image acquisition provides quantitative information on defect density and distribution on systems foreseen for future semiconductor devices.
Non‐rigid image registration of low‐dose image series of zeolite materials
Authors: Huang Chen , Berkels Benjamin , Kirkland Angus 
Published: December 2016

Zeolites are an important group of materials with a wide range of application in the catalysis industry. Many structural studies of zeolites rely on high resolution electron microscope imaging [1]. However, due to their high sensitivity to electron irradiation, zeolites deteriorate quickly under exposure to the electron beam. Low‐dose imaging techniques use a reduced electron flux to slow the crystal degradation process, which gives more time for adjustment of the microscope configuration and better control over the progression of damage. However the disadvantage of low‐dose imaging is poor signal to noise ratio which is often alleviated by averaging multiple image frames in a time series for improved image quality. Traditional rigid cross‐correlation function (XCF) image registration methods work well for aligning high‐dose time series of radiation‐robust materials which experience little or no deformation during image acquisition. However, the deformation in radiation‐sensitive materials, often manifest by sample shrinkage, means that the single translational shift vector from rigid image registration may not be sufficient for aligning time series and hence a non‐rigid registration scheme is needed.
In this work, a low‐dose time series of ZSM‐5 zeolite consisting 60 image frames were recorded using an aberration‐corrected JEOL2200MCO TEM (Figure 1). Two registration methods, a rigid XCF registration and a new non‐rigid registration, were used to align the series respectively. The non‐rigid registration method [2] is assisted by an IQ factor criterion, which evaluates the quality of the averaged image of the series as the registration proceeds and selects the best averaged image as the reference for future registration iterations.
The results show that the new non‐rigid registration is helpful for alignment of low‐dose TEM image series of radiation‐sensitive materials that experience deformation during imaging, especially when the number of frames is small and when the sample is already damaged (Figure 2). This implies that, for TEM image series, the non‐rigid registration approach is more effective in noise suppression and in avoiding the image components of a damaged sample compromising the final averaged image.
For further comparison, a low‐dose STEM time series of zeolite Y, was registered by both rigid and non‐rigid methods. A comparative analysis of IQ factor was carried out on the averaged images and showed that the non‐rigid registration consistently outperforms the rigid XCF registration (Figure 3). The reason for this advantage is attributed to the fact that the STEM images often suffer from additional scan noise due to the pixel‐by‐pixel acquisition in STEM imaging.
SI
ev: Implementation of an anisotropic binning strategy to optimize the chemical analysis of heterogeneous interfaces
Authors: Afonso Carlos F. , Carbó‐Argibay Enrique , Claro Marcel S. , Stroppa Daniel G. 
Published: December 2016

Outstanding properties emerge at the interfaces of heterogeneous materials, so that their engineering offers promising prospects for achieving novel functional structures. The design and realization of highly‐controlled interfaces require reliable characterization techniques with high spatial resolution and chemical sensitivity, and X‐rays Energy Dispersive Spectroscopy Spectrum Imaging (XEDS‐SI) has been used qualitatively for this purpose with ample success. However, the extraction of quantitative features from XEDS‐SI by the overall signal integration around the X‐rays peaks location tends to be inaccurate for high spatial resolution analysis due to their typically reduced signal to noise ratio.
This work presents a strategy for an improved and quantitative chemical analysis at the interface of heterostructures based on the processing of XEDS‐SI datasets obtained by aberration‐corrected Scanning Transmission Electron Microscopy (STEM). The successive XEDS‐SI dataset breakdown with decreasing binning sizes is implemented in the SIev software tool, and its application results in the improved detection of X‐rays peaks and estimation of local noise levels. This approach supports the actual chemical signal extraction from XEDS‐SI with the maximum spatial resolution with respect to signal to noise ratio (SNR) significance limit.
Results of anisotropic XEDS‐SI dataset breakdown obtained with aid of SIev software indicate that sub‐nm precision, considering a 2σ confidence level, can be routinely attained on the determination of a projected intermixing layer at the interface of heterogeneous materials. Given that the SIev data processing is significantly faster than a high‐SNR XEDS‐SI dataset acquisition by the use of currently available high efficiency X‐rays detectors, the perspective of an accurate and real‐time profile across the interfaces of heterogeneous materials via chemical mapping is foreseen.
Environmental Scanning Electron Microscopy applied to the identification of asbestos fibers in histological sections
Authors: Rinaudo Caterina , Croce Alessandro , Trincheri Nicol Francesca , Libener Roberta , Degiovanni Daniela , Grosso Federica 
Published: December 2016

The strong relation between inhaled asbestos fibers and development of important respiratory diseases (asbestosis, pulmonary carcinoma, mesothelioma) is now demonstrated by many researches and accepted by the international community. The peculiarity of the minerals defined by the law “asbestos” is their growth as long and thin fibers that, as a consequence of the crystal habit, reach the respiratory apparatus, where may lie during long times –decades‐ displaying their carcinogenic effects. The longer asbestos fibers may be coated by iron‐proteins, forming the well‐known “ferruginous bodies”, which represent a way to isolate the fiber in the biological system [1]. It must be remarked that the observation of fibers or ferruginous bodies allow to prove exposure, environmental or working, to asbestos. Nevertheless “ferruginous bodies” may be formed also around elongated minerals/crystals, not belonging to asbestos group. In order to determine surely exposure to asbestos it appears therefore very important to recognize the chemical composition of the fiber inside the coating and identify the mineral phase. A new methodology allowing the sure identification of the mineral phase of a fiber coated in a “ferruginous body” [2], using Environmental Scanning Electron Microscopy (E‐SEM) coupled with Energy Dispersive Spectroscopy (EDS), will be presented.
Our University is placed near Casale Monferrato, a town of Piedmont, Italy, sadly famous for the high incidence of asbestos related diseases, in particular mesothelioma, as consequence of the presence of an Eternit factory working large contents of asbestos until 1985. In several patients suffering of mesothelioma also serious disorders of the biliary tract and/or of the gallbladder have been often diagnosed. Nevertheless, the seriousness of the damages to the respiratory system reduce the attention to other organs. In order to determine the presence of asbestos fibers in the gallbladder or in the biliary tract of patients suffering both of mesothelioma and of disorders in this gland, histological sections of gallbladder and of bile have been observed under E‐SEM/EDS. All the inorganic phases observed have been characterized under their morphological and chemical aspects [3]. By this work it can be proved the presence of asbestos fibers or bundles of asbestos fibers, as shown in the figure, in particular of crocidolite and chrysotile, in almost all the examined sections. The results obtained during this work will be presented and discussed.
Evaluation of feature‐based registration algorithms for the improvement of tilt‐series alignment in electron tomography
Authors: Verguet Amandine , Trepout Sylvain , Marco Sergio , Messaoudi Cédric 
Published: December 2016

Despite the high performance achieved in goniometers‐control for tomographic tilt series recording, image alignment is mandatory to obtain accurate reconstructions. In addition, due to the high resolution currently expected from tomograms, the existing alignment methods (based on cross‐correlation, fiducial‐markers and landmarks) needs to be improved. Among the alternative methods presently proposed for general purpose image registration, Scale Invariant Feature Transform (SIFT) [1] has demonstrate its performance for the detection of common features occurring in several images. SIFT have been successfully used for panoramic stitching [2], object detection [1] and proposed as a method for image alignment in electron tomography [3].We have implemented SIFT and two other feature‐based registration algorithms porposed since the publication of SIFT (ORB [4], BRISK [5]) in TomoJ [6] and evaluated their respective performances on tilt series data from different transmission electron microscopy (TEM) acquisition methods (TEM, EFTEM, STEM, and Cryo‐TEM). We will present here the results obtained validating the use of feature‐based registration algorithms on tilt series from the different acquisition modes.