Max Planck Institute for Metals Research – 90 Years of Excellence in Materials Science

Keyword(s):  
2001 ◽  
Vol 7 (S2) ◽  
pp. 88-89
Author(s):  
Ingo Daberkow ◽  
Bernhard Feja ◽  
Peter Sparlinek ◽  
Hans R. Tietz

During the last decade, computation of a three-dimensional image from a tilt series (3D reconstruction) has become a well established method, of which a variety of implementations are available. The term “electron tomography” is now generally used for this type of data acquisition and 3D reconstruction. An overview over the techniques involved is given in.With the introduction of micro-processor-controlled TEMs and cooled slow-scan CCD cameras and with the progress in performance of high-speed computers, automation of complex imaging procedures became mainly a task of developing appropriate software, using the control facilities of the microscope. in this way, automated electron tomography was realized in 1990 at the Max- Planck-Institute for Biochemistry in Martinsried, and at about the same time at the University of California in San Francisco (UCSF). New techniques for automatic focusing and alignment, developed somewhat earlier , have been integrated in these automated tomography procedures. in the following we discuss the requirements of automatic data acquisition and the present implementation for several TEMs.


Synlett ◽  
2019 ◽  
Vol 30 (17) ◽  
pp. 1952-1953
Author(s):  
Bill Morandi

studied at the ETH Zurich from 2003–2012, earning a B.Sc. in biology, an M.Sc. in chemical biology and a Ph.D. in organic chemistry working with Prof. Erick M. Carreira. After a postdoc with Prof. Robert H. Grubbs at CalTech, he led an independent Max Planck Research Group from 2014–2018 at the Max-Planck-Institut für Kohlenforschung, Germany. Since July 2018, he is a tenured Associate Professor at the ETH Zurich where he holds a chair in synthetic organic chemistry. His independent research program targets the development of new concepts in catalysis, with a particular emphasis on employing inexpensive and sustainable catalysts to transform broadly available feedstocks, such as polyols and hydrocarbons, into valuable building blocks for applications in medicine and materials science.


Green ◽  
2015 ◽  
Vol 5 (1-6) ◽  
Author(s):  
Alexander A. Auer ◽  
Sébastien Cap ◽  
Markus Antonietti ◽  
Serhiy Cherevko ◽  
Xiaohui Deng ◽  
...  

AbstractMAXNET Energy is an initiative of the Max Planck society in which eight Max Planck institutes and two external partner institutions form a research consortium aiming at a deeper understanding of the electrocatalytic conversion of small molecules. We give an overview of the activities within the MAXNET Energy research consortium. The main focus of research is the electrocatalytic water splitting reaction with an emphasis on the anodic oxygen evolution reaction (OER). Activities span a broad range from creation of novel catalysts by means of chemical or material synthesis, characterization and analysis applying innovative electrochemical techniques, atomistic simulations of state-of-the-art x-ray spectroscopy up to model-based systems analysis of coupled reaction and transport mechanisms. Synergy between the partners in the consortium is generated by two modes of cooperation – one in which instrumentation, techniques and expertise are shared, and one in which common standard materials and test protocols are used jointly for optimal comparability of results and to direct further development. We outline the special structure of the research consortium, give an overview of its members and their expertise and review recent scientific achievements in materials science as well as chemical and physical analysis and techniques. Due to the extreme conditions a catalyst has to endure in the OER, a central requirement for a good oxygen evolution catalyst is not only its activity, but even more so its high stability. Hence, besides detailed degradation studies, a central feature of MAXNET Energy is a standardized test setup/protocol for catalyst stability, which we propose in this contribution.


Author(s):  
C. Colliex ◽  
P. Trebbia

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.


Author(s):  
Hannes Lichte ◽  
Edgar Voelkl

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.


Author(s):  
J.C.H. Spence ◽  
J. Mayer

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.


Author(s):  
Robert M. Glaeser ◽  
Bing K. Jap

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.


Author(s):  
M. Rühle ◽  
J. Mayer ◽  
J.C.H. Spence ◽  
J. Bihr ◽  
W. Probst ◽  
...  

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.


Author(s):  
Vinayak P. Dravid ◽  
M.R. Notis ◽  
C.E. Lyman

The concept of interfacial width is often invoked in many materials science phenomena which relate to the structure and properties of internal interfaces. The numerical value of interface width is an important input parameter in diffusion equations, sintering theories as well as in many electronic devices/processes. Most often, however, this value is guessed rather than determined or even estimated. In this paper we present a method of determining the effective structural and electronic- structural width of interphase interfaces using low- and core loss fine structure effects in EELS spectra.The specimens used in the study were directionally solidified eutectics (DSEs) in the system; NiO-ZrO2(CaO), NiO-Y2O3 and MnO-ZrO2(ss). EELS experiments were carried out using a VG HB-501 FE STEM and a Hitachi HF-2000 FE TEM.


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