Coordination nanosheets (CONASHs): strategies, structures and functions

2017 ◽  
Vol 53 (43) ◽  
pp. 5781-5801 ◽  
Author(s):  
Ryota Sakamoto ◽  
Kenji Takada ◽  
Tigmansu Pal ◽  
Hiroaki Maeda ◽  
Tetsuya Kambe ◽  
...  
Keyword(s):  
Materials Science ◽  
Rapid Progress ◽  
Feature Article ◽  
Present Feature

The present feature article assembles recent rapid progress in the coordination nanosheet (CONASH), the interest of which traverses from basic to materials science.

scholarly journals Recent Advances in Transmission Electron Microscopy for Materials Science at the EMAT Lab of the University of Antwerp

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1304 ◽  
Author(s):  
Giulio Guzzinati ◽  
Thomas Altantzis ◽  
Maria Batuk ◽  
Annick De Backer ◽  
Gunnar Lumbeeck ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Materials Science ◽  
Electron Tomography ◽  
High Resolution Imaging ◽  
Rapid Progress ◽  
Transmission Electron ◽  
The World ◽  
Resolution Imaging ◽  
The University

The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium’s foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab’s recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science.

scholarly journals New generations of spirobifluorene regioisomers for organic electronics: tuning electronic properties with the substitution pattern

2019 ◽  
Vol 55 (95) ◽  
pp. 14238-14254 ◽  
Author(s):  
Cyril Poriel ◽  
Lambert Sicard ◽  
Joëlle Rault-Berthelot
Keyword(s):  
Electronic Properties ◽  
Organic Electronics ◽  
Device Performance ◽  
Substitution Pattern ◽  
Feature Article ◽  
Present Feature ◽  
Positional Isomerism ◽  
The Impact

In the present feature article, we present the new generations of spirobifluorenes for organic electronics and we detail the impact of positional isomerism on the electronic properties and device performance.

Divergent Oxidative Couplings between Indoles and 2,3-Dihydroxybenzoic Acid Derivatives for the Biomimetic Synthesis of Voacalgine A and Bipleiophylline

Synthesis ◽  
2018 ◽  
Vol 50 (21) ◽  
pp. 4229-4242 ◽  
Author(s):  
Erwan Poupon ◽  
Laurent Evanno ◽  
Guillaume Vincent ◽  
Natacha Denizot ◽  
David Lachkar ◽  
...  
Keyword(s):  
Natural Products ◽  
Oxidative Coupling ◽  
Chemical Space ◽  
Biomimetic Synthesis ◽  
Dihydroxybenzoic Acid ◽  
Feature Article ◽  
Present Feature ◽  
Biosynthetic Precursor ◽  
Bisindole Alkaloid

The present feature article details our endeavors towards the synthesis of the highly intricate bisindole alkaloid bipleiophylline and its biosynthetic precursor voacalgine A: from the development of a divergent oxidative coupling between indole and dihydroxybenzoic acids, to the exploration of the chemical space from natural products and culminating in the biomimetic assembly of voacalgine A and bipleiophylline.

scholarly journals Recent advances in the application of total scattering methods to functional materials

2015 ◽  
Vol 51 (93) ◽  
pp. 16592-16604 ◽  
Author(s):  
Alessandro Mancini ◽  
Lorenzo Malavasi
Keyword(s):  
Materials Science ◽  
Functional Materials ◽  
Feature Article ◽  
Total Scattering ◽  
Recent Advances ◽  
Pdf Analysis

In this Feature Article, we provide a description of some of the most recent results obtained in the field of materials science by means of total scattering methods and PDF analysis.

Organocatalytic routes toward substituted 1,2,3-triazoles

2015 ◽  
Vol 51 (54) ◽  
pp. 10797-10806 ◽  
Author(s):  
Jubi John ◽  
Joice Thomas ◽  
Wim Dehaen
Keyword(s):  
Feature Article ◽  
Present Feature

The present feature article describes the different organocatalytic routes for the synthesis of substituted 1,2,3-triazoles.

Trends in Electron Energy Loss Spectroscopy

1977 ◽  
Vol 35 ◽  
pp. 228-229
Author(s):  
C. Colliex ◽  
P. Trebbia
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Materials Science ◽  
Analytical Technique ◽  
Recent Developments ◽  
Quantitative Results ◽  
Electron Microscopes ◽  
Electron Energy Loss ◽  
Primary Electrons

The physical foundations for the use of electron energy loss spectroscopy towards analytical purposes, seem now rather well established and have been extensively discussed through recent publications. In this brief review we intend only to mention most recent developments in this field, which became available to our knowledge. We derive also some lines of discussion to define more clearly the limits of this analytical technique in materials science problems.The spectral information carried in both low ( 0<ΔE<100eV ) and high ( >100eV ) energy regions of the loss spectrum, is capable to provide quantitative results. Spectrometers have therefore been designed to work with all kinds of electron microscopes and to cover large energy ranges for the detection of inelastically scattered electrons (for instance the L-edge of molybdenum at 2500eV has been measured by van Zuylen with primary electrons of 80 kV). It is rather easy to fix a post-specimen magnetic optics on a STEM, but Crewe has recently underlined that great care should be devoted to optimize the collecting power and the energy resolution of the whole system.

Electron holography in materials science

1991 ◽  
Vol 49 ◽  
pp. 670-671
Author(s):  
Hannes Lichte ◽  
Edgar Voelkl
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Materials Science ◽  
Fourier Spectrum ◽  
Object Wave ◽  
Electron Holography ◽  
Reconstruction Procedure ◽  
Numerical Reconstruction ◽  
Transmission Electron ◽  
Unique Interpretation

The object wave o(x,y) = a(x,y)exp(iφ(x,y)) at the exit face of the specimen is described by two real functions, i.e. amplitude a(x,y) and phase φ(x,y). In stead of o(x,y), however, in conventional transmission electron microscopy one records only the real intensity I(x,y) of the image wave b(x,y) loosing the image phase. In addition, referred to the object wave, b(x,y) is heavily distorted by the aberrations of the microscope giving rise to loss of resolution. Dealing with strong objects, a unique interpretation of the micrograph in terms of amplitude and phase of the object is not possible. According to Gabor, holography helps in that it records the image wave completely by both amplitude and phase. Subsequently, by means of a numerical reconstruction procedure, b(x,y) is deconvoluted from aberrations to retrieve o(x,y). Likewise, the Fourier spectrum of the object wave is at hand. Without the restrictions sketched above, the investigation of the object can be performed by different reconstruction procedures on one hologram. The holograms were taken by means of a Philips EM420-FEG with an electron biprism at 100 kV.

Zero-loss omega-filtered REM and RHEED on the new Zeiss 912

1991 ◽  
Vol 49 ◽  
pp. 616-617
Author(s):  
J.C.H. Spence ◽  
J. Mayer
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Surface States ◽  
Ccd Camera ◽  
Dark Field ◽  
Ion Pump ◽  
Magnetic Imaging ◽  
Reflection Electron Microscopy ◽  
Diffraction Patterns ◽  
Large Background

The Zeiss 912 is a new fully digital, side-entry, 120 Kv TEM/STEM instrument for materials science, fitted with an omega magnetic imaging energy filter. Pumping is by turbopump and ion pump. The magnetic imaging filter allows energy-filtered images or diffraction patterns to be recorded without scanning using efficient parallel (area) detection. The energy loss intensity distribution may also be displayed on the screen, and recorded by scanning it over the PMT supplied. If a CCD camera is fitted and suitable new software developed, “parallel ELS” recording results. For large fields of view, filtered images can be recorded much more efficiently than by Scanning Reflection Electron Microscopy, and the large background of inelastic scattering removed. We have therefore evaluated the 912 for REM and RHEED applications. Causes of streaking and resonance in RHEED patterns are being studied, and a more quantitative analysis of CBRED patterns may be possible. Dark field band-gap REM imaging of surface states may also be possible.

Dynamical Scattering in Crystalline Biological Specimens. I. Criteria of Validity for Scattering Approximations

1975 ◽  
Vol 33 ◽  
pp. 192-193
Author(s):  
Robert M. Glaeser ◽  
Bing K. Jap
Keyword(s):  
Biological Sciences ◽  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Born Approximation ◽  
Materials Science ◽  
Image Data ◽  
Dynamical Effect ◽  
Crystallographic Structure ◽  
Electron Microscope Image

The dynamical scattering effect, which can be described as the failure of the first Born approximation, is perhaps the most important factor that has prevented the widespread use of electron diffraction intensities for crystallographic structure determination. It would seem to be quite certain that dynamical effects will also interfere with structure analysis based upon electron microscope image data, whenever the dynamical effect seriously perturbs the diffracted wave. While it is normally taken for granted that the dynamical effect must be taken into consideration in materials science applications of electron microscopy, very little attention has been given to this problem in the biological sciences.

Electron spectroscopic imaging and diffraction

1991 ◽  
Vol 49 ◽  
pp. 706-707
Author(s):  
M. Rühle ◽  
J. Mayer ◽  
J.C.H. Spence ◽  
J. Bihr ◽  
W. Probst ◽  
...  
Keyword(s):  
Materials Science ◽  
Electron Spectroscopic Imaging ◽  
Magnetic Filter ◽  
Magnetic Imaging ◽  
Illumination System ◽  
Probe Size ◽  
Diffraction Patterns ◽  
Fritz Haber ◽  
Koehler Illumination ◽  
First Time

A new Zeiss TEM with an imaging Omega filter is a fully digitized, side-entry, 120 kV TEM/STEM instrument for materials science. The machine possesses an Omega magnetic imaging energy filter (see Fig. 1) placed between the third and fourth projector lens. Lanio designed the filter and a prototype was built at the Fritz-Haber-Institut in Berlin, Germany. The imaging magnetic filter allows energy-filtered images or diffraction patterns to be recorded without scanning using efficient area detection. The energy dispersion at the exit slit (Fig. 1) results in ∼ 1.5 μm/eV which allows imaging with energy windows of ≤ 10 eV. The smallest probe size of the microscope is 1.6 nm and the Koehler illumination system is used for the first time in a TEM. Serial recording of EELS spectra with a resolution < 1 eV is possible. The digital control allows X,Y,Z coordinates and tilt settings to be stored and later recalled.

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