scholarly journals Applications of Discrete Synthetic Macromolecules in Life and Materials Science: Recent and Future Trends

2021 ◽  
pp. 2004038
Author(s):  
Resat Aksakal ◽  
Chiel Mertens ◽  
Matthieu Soete ◽  
Nezha Badi ◽  
Filip Du Prez
Author(s):  
Gareth Thomas

The Optimum Voltages for Electron Microscopy – The advantages of high voltage electron microscopy are now well established, and many applications, such as use of environmental cells both in metallurgy and biology, are now possible. However recent experiments at Toulouse indicate that except for light elements, there is no appreciable gain in transmission for a given resolution level as the energy is increased above 1 MeV (see Fig. 1). These results are not as optimistic as theory might indicate. Special effects such as critical voltages above 1 MeV are of interest, but knock-on radiation damage imposes limitations on many applications. Thus it would appear that 1 MeV is a reasonable upper limit for most applications in materials science.


2011 ◽  
Vol 21 (4) ◽  
pp. 1 ◽  
Author(s):  
Leszek Wojnar

Relation between image analysis and stereology is discussed in terms of different fields of applications, especially materials science, biology and medicine. Some long-term tendencies observed as well as possible future trends are discussed. The need of a wider use of image analysis techniques including ma1hematical morphology in any field of science is demons1rated. Simultaneously, the significance of stereological background in automatic quantification of1he investigated structures is confirmed.


Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 261 ◽  
Author(s):  
Christopher Stephen Andrew Musgrave ◽  
Fengzhou Fang

More is demanded from ophthalmic treatments using contact lenses, which are currently used by over 125 million people around the world. Improving the material of contact lenses (CLs) is a now rapidly evolving discipline. These materials are developing alongside the advances made in related biomaterials for applications such as drug delivery. Contact lens materials are typically based on polymer- or silicone-hydrogel, with additional manufacturing technologies employed to produce the final lens. These processes are simply not enough to meet the increasing demands from CLs and the ever-increasing number of contact lens (CL) users. This review provides an advanced perspective on contact lens materials, with an emphasis on materials science employed in developing new CLs. The future trends for CL materials are to graft, incapsulate, or modify the classic CL material structure to provide new or improved functionality. In this paper, we discuss some of the fundamental material properties, present an outlook from related emerging biomaterials, and provide viewpoints of precision manufacturing in CL development.


MRS Bulletin ◽  
2003 ◽  
Vol 28 (6) ◽  
pp. 419-423 ◽  
Author(s):  
Costantino Creton ◽  
Eric Papon

AbstractThis issue of MRS Bulletin provides an overview of the state of the art and emerging trends in the area of adhesives. An adhesive is basically defined by its function, which is to assemble two surfaces together. In order to fulfill this function, the properties of an adhesive must include easy positioning at the interface, rapid and complete bond formation and subsequent hardening, and a bond strength adapted to the specific application (structural, permanent, removable, rigid, or soft). A variety of solutions exist in practice, and their application requires an understanding both of polymer chemistry and materials science. The main families of adhesives, their properties, and their basic design principles will be discussed in the articles in this issue, while this introductory article presents an overview of the functions required of adhesives and future trends.


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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