Metastable Superstructures in RuSr2Gd1.4Ce0.6Cu2O10-δ?Superconductor Based on TEM Observation at Room Temperature

2001 ◽  
Vol 689 ◽  
Author(s):  
Li Yang ◽  
J. M. Vieira ◽  
Kaibin Tang ◽  
Guien Zhou
Keyword(s):  
Electron Beam ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Storage Time ◽  
Point Of View ◽  
Tetragonal Symmetry ◽  
Sample Storage ◽  
Unconventional Superconductor ◽  
Fluorite Type ◽  
Structural Point

ABSTRACTThree types of metastable modulations in Ru-based superconductor RuSr2Gd1.4Ce0.6Cu2O10-δ are observed by electron diffraction at room temperature and reported in this paper. The modulations are sensitive to the irradiation of the electron beam and the sample storage time. Having the tetragonal symmetry (I4/mmm) with a=0.384nm, c=2.864nm, the structure of RuSr2Gd1.4Ce0.6Cu2O10-δ?resembles that of YBa2Cu3O7-δ by inserting a fluorite type Gd1.4Ce0.6O2 layer instead of the Y layer and Ru ions residing in the Cu(1) site. In this compound, superconductivity is confined to the CuO2 layer while magnetism stems from the RuO2 layer. The metastable modulations display the interaction between the two layers from the structural point of view. The results suggest that although, superconductivity and magnetism are decoupled from each other in the unconventional superconductor, the effect may be limited by metastable lattice modulation.

A microscopic system for high-resolution electron crystallography

1995 ◽  
Vol 53 ◽  
pp. 70-71
Author(s):  
Y. Fujiyoshi ◽  
K. Murata ◽  
K. Mitsuoka ◽  
T. Hirai ◽  
A. Miyazawa ◽  
...  
Keyword(s):  
High Resolution ◽  
Structure Analysis ◽  
Room Temperature ◽  
Point Of View ◽  
Irradiation Damage ◽  
High Resolution Data ◽  
Light Harvesting Complex ◽  
Resolution Electron ◽  
Structural Point ◽  
Resolution Data

High-resolution electron cryo-microscopy is one of good candidate for structure analysis of membrane-protein, and also actually analyzed the structure of membrane-proteins such as bacteriorhodopsin (bR) and plant light-harvesting complex (LHC). By developing an expeditious method for structure analysis up to atomic or near atomic resolution, we would like to interpret a function of protein from the structural point of view. However, there are some difficulties in electron microscopy for structure analysis of protein. Especially, the most serious problems are the specimen damage caused by electron irradiation, the denaturation of biomolecules caused by dehydration and missing high-resolution data on electron micrographs at high-tilted angle.The irradiation damage at 8K has been found to be reduced to 1/20 compared with that at room temperature. We have, therefore, developed a high-resolution electron cryo-microscope and improved it by which images can be recorded with higher resolution than 3 Å at a specimen-stage temperature of 4.2 K, even when the specimen is highly tilted. The highly tilted data are essential for reduction of the missing corn effect.

Isotope Effect in TlH2PO4 and TlD2PO4

1998 ◽  
Vol 54 (6) ◽  
pp. 790-797 ◽  
Author(s):  
S. Ríos ◽  
W. Paulus ◽  
A. Cousson ◽  
M. Quilichini ◽  
G. Heger
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Room Temperature ◽  
Point Of View ◽  
Temperature Phase ◽  
Neutron Diffraction Data ◽  
Antiferroelectric Phase ◽  
Low Temperature Phase ◽  
Structural Point ◽  
Prototype Phase

The crystal structure of the antiferroelectric phase of TlD2PO4, deuterated thallium dihydrogenphosphate, has been determined from single-crystal neutron diffraction data collected at room temperature. The para-antiferroelectric transition (T_c^d = 353 K) of TlD2PO4 is analysed from a structural point of view and compared with the phase transition of TlH2PO4 at TI = 357 K, already characterized. The distinct phase sequences observed in the two compounds when decreasing temperature from that of the high-temperature prototype phase (prototype phase/room-temperature phase/low-temperature phase) are discussed and associated with the different ordering of the two crystallographically inequivalent H (D) atoms existing in the prototype phase.

Effect of Thermal Treatment on Enzymatic Activity and Rheological and Sensory Properties of Strawberry Purees

2008 ◽  
Vol 14 (5_suppl) ◽  
pp. 103-108 ◽  
Author(s):  
O. Osorio ◽  
N. Martínez-Navarrete ◽  
G. Moraga ◽  
J.V. Carbonell
Keyword(s):  
Room Temperature ◽  
Storage Time ◽  
Sensory Quality ◽  
Pectin Methylesterase ◽  
Taste Quality ◽  
Point Of View ◽  
Thermal Treatments ◽  
Three Samples ◽  
Thermally Treated

The behavior of strawberry purees submitted to processes of mild pasteurization (75 °C — 15 s) and severe pasteurization (90 °C — 20 s), using as references fresh and hot-filled purees, was studied. Purees thermally treated were stored at +3 °C during 2 months. Pectin methylesterase activity, rheological behavior, and taste quality were analyzed. The results showed how the pectin methylesterase activity of strawberry puree (0.385nanokatal/mL) was reduced to 25.5% by the mild heat treatment, to 5.4% by the severe one and to undetectable levels in the hot-filled puree. A significant increase in the viscosity was detected as a consequence of the severe thermal treatments, although in any case it decreased with storage time. Taste quality, evaluated by simple ranking tests of samples, was superior in the fresh puree, without significant differences among the three samples thermally treated. The assessors pointed out the greater aromatic intensity of the fresh puree and the lack of cooked flavors in all samples. All treated samples maintained their sensory quality during 2 months of storage at 3 °C. The taste quality of hot-filled purees stored 1 or 2 months at room temperature (21 °C) was significantly lower than the respective chilled samples. From this point of view, the hot-filled treatment and chilling storage will be recommended for this product.

Chitin Systems Studied by Electron Diffraction, Diffraction-Contrast Electron Microscopy and Lattice Imaging

1990 ◽  
Vol 48 (1) ◽  
pp. 582-583 ◽  
Author(s):  
Henri CHANZY ◽  
Francoise Gaill ◽  
Marie-Madeleine Giraud-Guille ◽  
Jan Persson ◽  
Junji Sugiyama ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Electron Diffraction ◽  
Cross Sections ◽  
Room Temperature ◽  
Lattice Imaging ◽  
Diffraction Contrast ◽  
Transmission Electron ◽  
Tevnia Jerichonana

Chitin the poly β (1-4)-N Acetyl D glucosamine is widespread in nature and occurs normally as a crystalline fibrillar substance. As opposed to most of the crystalline polysaccharides, chitin is quite resistant to the electron beam. In particular, at room temperature, accumulated doses as high as 200 elec/nm2 at 120 kV can be used to record successful images showing crystalline details. For this reason, chitin can be studied without too much difficulty by electron diffraction (ED), diffraction contrast transmission electron microscopy (DCTEM) and lattice imaging. This study presents some of the diversity of chitin morphology.Several chitin rich specimens were studied. They include : 1) cross sections of an ovipositor from an ichneumon fly Rhyssa persuosaria ; 2) cross sections of fragments of demineralized crab cuticle ; 3) cross sections of a tube from the vestimentiferan worm Tevnia jerichonana ; 4) bundles of chitin microfibrils isolated from Tevnia tube fragments after deproteinization.

The Technology and Storage Stability Studies of Yam Functional Food

2014 ◽  
Vol 687-691 ◽  
pp. 4515-4519
Author(s):  
Jian Chun Zhao
Keyword(s):  
Functional Food ◽  
Room Temperature ◽  
Storage Time ◽  
Storage Stability ◽  
Stability Studies ◽  
Sample Storage ◽  
Room Temperature Sample ◽  
Index Changes ◽  
And Storage ◽  
Temperature Sample

In this paper, yam functional food technology and storage stability were studied, the results indicate that storage time and temperature on the results significantly higher than room temperature sample storage, cryogenic sample index changes significantly, the moisture content of the sample affect the sensory scores larger.

scholarly journals Preanalytical Factors That Influence the Abbott TDx Fetal Lung Maturity II Assay

2003 ◽  
Vol 49 (6) ◽  
pp. 935-939 ◽  
Author(s):  
David G Grenache ◽  
Curtis A Parvin ◽  
Ann M Gronowski
Keyword(s):  
Whole Blood ◽  
Room Temperature ◽  
Storage Time ◽  
Fetal Lung ◽  
Sample Storage ◽  
Blood Contamination ◽  
Fetal Lung Maturity ◽  
Baseline Values ◽  
Lung Maturity ◽  
Over Time

Abstract Background: The TDx Fetal Lung Maturity II (FLM II) assay uses amniotic fluid to assess lung maturity of the unborn infant. We investigated common preanalytical factors that influence FLM results, including centrifugation, sample storage, and contamination by whole blood. Methods: We tested 18 specimens after centrifugation and after resuspension by vortex-mixing. We also analyzed 23 specimens stored at −20 °C for up to 448 days and then thawed (duplicate measurements), 20 specimens stored at 4 °C, and 24 specimens stored at room temperature. In addition, we evaluated the effects of whole blood diluted into 19 different specimens. Results: Centrifugation significantly decreased FLM II results from baseline (P <0.0001), and resuspension returned results to baseline values (P = 0.286). Storage at −20 °C produced highly variable results that demonstrated a nonsignificant negative trend associated with storage time. Specimens were stable for 24 h when stored at 4 °C and 16 h at room temperature. Blood contamination produced significantly positive differences in results only in specimens with baseline values ≤39 mg/g with a 5.8 mg/g increase in FLM II for every 0.1 × 1012/L increase in the erythrocyte count (slope = 58.4). Conclusions: Resuspension of centrifuged specimens produces clinically valid FLM II results. Results from specimens stored at −20 °C can be highly variable and decrease over time. Results from specimens stored at 4 °C and at room temperature are stable for 24 and 16 h, respectively. Blood contamination up to 0.03 × 1012 erythrocytes/L is acceptable for FLM II analysis.

Domain Formation in Synthetic Quartz

1971 ◽  
Vol 29 ◽  
pp. 156-157
Author(s):  
Joseph J. Comer
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Domain Formation ◽  
Synthetic Quartz ◽  
Transmission Electron ◽  
Black Spots ◽  
Diffraction Mode ◽  
Domain Boundaries ◽  
Kikuchi Lines ◽  
Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

Quanitative aspects of electron diffraction using electron holography

1995 ◽  
Vol 53 ◽  
pp. 616-617
Author(s):  
E. Völkl ◽  
L.F. Allard ◽  
B. Frost ◽  
T.A. Nolan
Keyword(s):  
Electron Beam ◽  
Electron Diffraction ◽  
Software Package ◽  
Spatial Coherence ◽  
Electron Holography ◽  
Image Intensity ◽  
Interference Fringes ◽  
Complex Image ◽  
The Difference ◽  
Recorded Image

Off-axis electron holography has the well known ability to preserve the complex image wave within the final, recorded image. This final image described by I(x,y) = I(r) contains contributions from the image intensity of the elastically scattered electrons IeI (r) = |A(r) exp (iΦ(r)) |, the contributions from the inelastically scattered electrons IineI (r), and the complex image wave Ψ = A(r) exp(iΦ(r)) as:(1) I(r) = IeI (r) + Iinel (r) + μ A(r) cos(2π Δk r + Φ(r))where the constant μ describes the contrast of the interference fringes which are related to the spatial coherence of the electron beam, and Φk is the resulting vector of the difference of the wavefront vectors of the two overlaping beams. Using a software package like HoloWorks, the complex image wave Ψ can be extracted.

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

Observation of the Sulphur Atoms in Cu2S Using HREM

1990 ◽  
Vol 48 (1) ◽  
pp. 38-39
Author(s):  
Y.D. Yu ◽  
R. Guan ◽  
K.H. Kuo ◽  
H. Hashimoto
Keyword(s):  
Electron Diffraction ◽  
Tube Wall ◽  
Present Report ◽  
Dynamic Effect ◽  
Glass Tube ◽  
Fluorite Structure ◽  
Point Of View ◽  
Electron Diffraction Analysis ◽  
Sulphur Atom ◽  
Copper Thin Film

We have indicated that the lighter atoms such as oxygen in Cu2O can be observed at the specimen with optimal thicknesses based on the dynamic effect of electron diffraction(1). This rule in principle should hold good for the imaging of other lighter atoms such as sulphur atom in Cu2S. However, this point of view needs further experimentally confirm because up to now only oxygen atoms have been observed in Cu2O and a series of new suboxides of copper and nickel (2). In addition, the sulphur atom is much heavier than oxygen one though is still lighter than copper atom. In the present report we provide such a confirmation.The crystallites of Cu2S shown in Fig.l were obtained by sulfurizing at 300°C of the copper thin film which was sealed in a glass tube with mg sulphur left on the tube wall in a vacuum of about 10-2 Pa. The energy dispersive spectrocscopy analysis indicated that they are the sulfides and the electron diffraction analysis indicated they have anti-fluorite structure.

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