Industrial Developments in the Field of Optically Transparent Inorganic Materials: A Survey of Recent Patents

2010 ◽  
Vol 1 (1) ◽  
pp. 56-73 ◽  
Author(s):  
Aldo R. Boccaccini ◽  
Deborah D. Silva
Author(s):  
D. J. Barber ◽  
R. G. Evans

Manganese (II) oxide, MnO, in common with CoO, NiO and FeO, possesses the NaCl structure and shows antiferromagnetism below its Neel point, Tn∼ 122 K. However, the defect chemistry of the four oxides is different and the magnetic structures are not identical. The non-stoichiometry in MnO2 small (∼2%) and below the Tn the spins lie in (111) planes. Previous work reported observations of magnetic features in CoO and NiO. The aim of our work was to find explanations for certain resonance results on antiferromagnetic MnO.Foils of single crystal MnO were prepared from shaped discs by dissolution in a mixture of HCl and HNO3. Optical microscopy revealed that the etch-pitted foils contained cruciform-shaped precipitates, often thick and proud of the surface but red-colored when optically transparent (MnO is green). Electron diffraction and probe microanalysis indicated that the precipitates were Mn2O3, in contrast with recent findings of Co3O4 in CoO.


Author(s):  
David J. Smith

The era of atomic-resolution electron microscopy has finally arrived. In virtually all inorganic materials, including oxides, metals, semiconductors and ceramics, it is possible to image individual atomic columns in low-index zone-axis projections. A whole host of important materials’ problems involving defects and departures from nonstoichiometry on the atomic scale are waiting to be tackled by the new generation of intermediate voltage (300-400keV) electron microscopes. In this review, some existing problems and limitations associated with imaging inorganic materials are briefly discussed. The more immediate problems encountered with organic and biological materials are considered elsewhere.Microscope resolution. It is less than a decade since the state-of-the-art, commercially available TEM was a 200kV instrument with a spherical aberration coefficient of 1.2mm, and an interpretable resolution limit (ie. first zero crossover of the contrast transfer function) of 2.5A.


Author(s):  
Patricia G. Arscott ◽  
Gil Lee ◽  
Victor A. Bloomfield ◽  
D. Fennell Evans

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).


Author(s):  
Philippe Pradère ◽  
Edwin L. Thomas

High Resolution Electron Microscopy (HREM) is a very powerful technique for the study of crystal defects at the molecular level. Unfortunately polymer crystals are beam sensitive and are destroyed almost instantly under the typical HREM imaging conditions used for inorganic materials. Recent developments of low dose imaging at low magnification have nevertheless permitted the attainment of lattice images of very radiation sensitive polymers such as poly-4-methylpentene-1 and enabled molecular level studies of crystal defects in somewhat more resistant ones such as polyparaxylylene (PPX) [2].With low dose conditions the images obtained are very noisy. Noise arises from the support film, photographic emulsion granularity and in particular, the statistical distribution of electrons at the typical doses of only few electrons per unit resolution area. Figure 1 shows the shapes of electron distribution, according to the Poisson formula :


Author(s):  
S. Horiuchi ◽  
Y. Matsui

A new high-voltage electron microscope (H-1500) specially aiming at super-high-resolution (1.0 Å point-to-point resolution) is now installed in National Institute for Research in Inorganic Materials ( NIRIM ), in collaboration with Hitachi Ltd. The national budget of about 1 billion yen including that for a new building has been spent for the construction in the last two years (1988-1989). Here we introduce some essential characteristics of the microscope.(1) According to the analysis on the magnetic field in an electron lens, based on the finite-element-method, the spherical as well as chromatic aberration coefficients ( Cs and Cc ). which enables us to reach the resolving power of 1.0Å. have been estimated as a function of the accelerating As a result of the calculaton. it was noted that more than 1250 kV is needed even when we apply the highest level of the technology and materials available at present. On the other hand, we must consider the protection against the leakage of X-ray. We have then decided to set the conventional accelerating voltage at 1300 kV. However. the maximum accessible voltage is 1500 kV, which is practically important to realize higher voltage stabillity. At 1300 kV it is expected that Cs= 1.7 mm and Cc=3.4 mm with the attachment of the specimen holder, which tilts bi-axially in an angle of 35° ( Fig.1 ). In order to minimize the value of Cc a small tank is additionally placed inside the generator tank, which must serve to seal the magnetic field around the acceleration tube. An electron gun with LaB6 tip is used.


2016 ◽  
Vol 38 (3) ◽  
pp. 205-210
Author(s):  
L.A. Bulavin ◽  
◽  
Yu.F. Zabashta ◽  
О.О. Brovko ◽  
L.Yu. Vergun ◽  
...  

2003 ◽  
Vol 773 ◽  
Author(s):  
C. Tamerler ◽  
S. Dinçer ◽  
D. Heidel ◽  
N. Karagûler ◽  
M. Sarikaya

AbstractProteins, one of the building blocks in organisms, not only control the assembly in biological systems but also provide most of their complex functions. It may be possible to assemble materials for practical technological applications utilizing the unique advantages provided by proteins. Here we discuss molecular biomimetic pathways in the quest for imitating biology at the molecular scale via protein engineering. We use combinatorial biology protocols to select short polypeptides that have affinity to inorganic materials and use them in assembling novel hybrid materials. We give an overview of some of the recent developments of molecular engineering towards this goal. Inorganic surface specific proteins were identified by using cell surface and phage display technologies. Examples of metal and metal oxide specific polypeptides were represented with an emphasis on certain level of specificities. The recognition and self assembling characteristics of these inorganic-binding proteins would be employed in develeopment of hybrid multifunctional materials for novel bio- and nano-technological applications.


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