Self-Assembled Cobalt Oxide Nanocrystals with Tetrahedral Shape

1998 ◽  
Vol 4 (S2) ◽  
pp. 736-737
Author(s):  
J.S. Yin ◽  
Z.L. Wang
Keyword(s):  
Cobalt Oxide ◽  
Materials Science ◽  
Surface Active Agent ◽  
Active Agent ◽  
Vertical Direction ◽  
Building Blocks ◽  
Research Field ◽  
In Situ Tem ◽  
Small Magnetic Field

Nanocrystal materials are an emerging research field of chemistry, physics and materials science. The size and shape specificity of nanocrystals suggests them as building blocks for constructing selfassembly passivated nanocrystals superlattices (NCS's) or nanocrystals arrays (NCA) [1-6]. In this paper, NCAs of CoO with controlled tetrahedral shape are reported and their structural stability is examined by in-situ TEM.Cobalt oxide nanocrystals were synthesized by chemical decomposition of Co2(CO)8 in toluene under oxygen atmosphere, as given in detail elsewhere [1].Sodium bis(2-ethylhexyl) sulfosuccinate (Na(AOT)) was added as a surface active agent, forming an ordered monolayer passivation (called the thiolate) over the nanocrystal surface. The particle size was controlled by adjusting the wt.% ratio between the precursor and Na(AOT). The as-prepared solution contained Co, CoO and possibly C03O4 nanoparticles, and pure CoO nanoparticles were separated by applying a small magnetic field, which is generated by a horseshoe permanent magnet in vertical direction.

HREM study of phase transformation induced by ion irradiation in Al-Cu-Co-Ge single decagonal quasicrystal

1996 ◽  
Vol 54 ◽  
pp. 722-723
Author(s):  
L.F. Chen ◽  
L.M. Wang ◽  
R.C. Ewing
Keyword(s):  
Phase Transformation ◽  
Ion Irradiation ◽  
National Laboratory ◽  
Research Field ◽  
In Situ Tem ◽  
Decagonal Quasicrystal ◽  
University Of New Mexico ◽  
Fundamental Understanding ◽  
The University

Irradiation-induced phase transformation in crystals has been an interesting research field for the past twenty years. Since the discovery of quasicrystals in Al-based alloys, there have been some reports on irradiation-induced phase transformation in quasicrystals by in situ TEM observations. However, detailed study on phase transformation in quasicrystals under ion irradiation at atomic level using HREM is necessary for the fundamental understanding of the process. In this paper, we report the results from a systematic HREM study on phase transformation induced by ion irradiation in Al-Cu-Co-Ge single decagonal quasicrystal (31.4 wt.% Cu, 21.8 wt.% Co and 5.4 wt.% Ge).The TEM specimens of single decagonal quasicrystal were prepared perpendicular to the tenfold axis. The transformation in single quasicrystal was studied by in situ TEM during 1.5 MeV Xe+ ion irradiation at room temperature using the HVEM-Tandem Facility at Argon National Laboratory and examined in detail by HREM using a JEM2010 microscope at the University of New Mexico after the irradiation.

Physical changes in the rhizosphere and their significance for plant-soil interactions

2000 ◽  
Vol 48 (1) ◽  
pp. 107-112 ◽  
Author(s):  
P. Gregory
Keyword(s):  
Surface Active Agent ◽  
Active Agent ◽  
Root Surface ◽  
Cone Beam ◽  
Non Invasive ◽  
Plant Soil ◽  
Scanning Time ◽  
Surface Active ◽  
Physical Changes

The rhizosphere has biological, chemical and physical properties that differ from those of bulk soil and which influence the availability of water and nutrients. Mucilage produced by roots contains a surface active agent which reduces the surface tension around the root. The presence of root cap cells in the mucilage gives it viscoelastic properties which draw soil particles towards the root surface and, together with the increasing viscosity as the soil dries and mucilage dehydrates, facilitates the formation of rhizosheaths.The development of non-invasive imaging allied with computed tomography (CT) has allowed the study of root systems in situ and the observation of root growth. It is now possible to achieve cone beam images in a scanning time of 30 minutes with a resolution of 100 .m. Further developments of this technique should allow changes in bulk density and water content close to the root surface to be observed and quantified.

scholarly journals Mycoremediation of an Agricultural Salty Soil Contaminated With Endosulfan by Penicillium Crustosum 

2020 ◽  
Author(s):  
Anbu Landa ◽  
Refugio Rodríguez Vázquez ◽  
Teresa Guadalupe Roldán Carillo
Keyword(s):  
Surface Active Agent ◽  
Active Agent ◽  
Biological Surface ◽  
Penicillium Crustosum ◽  
Oxidative Pathway ◽  
Agricultural Applications ◽  
Negative Effect ◽  
Metabolites Production ◽  
First Time

Abstract This is the first report about the application of Penicillium crustosum isolated from Citrus sinensis peel for endosulfan biodegradation and improvement of soil characteristics of a salty agricultural soil contamined with endosulfan; getting a degradation of 93 ± 4.7%, after one month of treatment. Metabolites production was also evaluated, finding that sulphate endosulfan and mono alcohol endosulfan were the main compounds produced for that reason an oxidative pathway is suggest. Degradation was enhanced by the biological surface active agent produced by the fungus during soil mycoremediation, where a DST up to 17 ± 0.58 mN m-1, was determined, being the first time that the in situ production for this kind of application was studies. Additionally, an improvement in soil quality (reduction of clay and salinity, and an increase of soluble phosphorus, carbon content and organic matter) was observed during the mycoremediation process. The phytotoxicity of the pesticide on Phaseolus leptostachyus crop was evaluated; in the soil without the fungus the pesticide translocated into the crop, presenting a negative effect in germination index, root length and weight, aerial weight and proline content. This contrasted with the crop develop in the soil treated with P. crustosum, which had better agronomic characteristics. In general, was possible appreciated that the addition of P. crustosum, present a lot of benefits for agricultural applications.

In Situ Transmission Electron Microscope Studies of Ion Irradiation-Induced and Irradiation-Enhanced Phase Changes

1991 ◽  
Vol 235 ◽  
Author(s):  
Charles W. Allen
Keyword(s):  
Materials Science ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Phase Changes ◽  
In Situ Tem ◽  
Irradiation Effects ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Electron Microscopes

ABSTRACTMotivated at least initially by materials needs for nuclear reactor development, extensive irradiation effects studies employing transmission electron microscopes (TEM) have been performed for several decades, involving irradiation-induced and irradiation-enhanced microstructural changes, including phase transformations such as precipitation, dissolution, crystallization, amorphization, and order-disorder phenomena. From the introduction of commercial high voltage electron microscopes (HVEM) in the mid-1960s, studies of electron irradiation effects have constituted a major aspect of HVEM application in materials science. For irradiation effects studies two additional developments have had particularly significant impact; (1) the development of TEM specimen holders in which specimen temperature can be controlled in the range 10–2200 K and (2) the interfacing of ion accelerators which allows in situ TEM studies of irradiation effects and the ion beam modification of materials within this broad temperature range. This paper treats several aspects of in situ studies of electron and ion beam-induced and enhanced phase changes and presents two case studies involving in situ experiments performed in an HVEM to illustrate the strategies of such an approach of the materials research of irradiation effects.

In situ TEM of silicon oxidation

1992 ◽  
Vol 50 (1) ◽  
pp. 324-325
Author(s):  
J. Murray Gibson ◽  
F.M. Ross ◽  
R.D. Twesten
Keyword(s):  
Materials Science ◽  
Oxidation Process ◽  
Electronic Device ◽  
Model System ◽  
Device Fabrication ◽  
In Situ Tem ◽  
Important Process ◽  
Silicon Oxidation ◽  
Electronic Device Fabrication

Oxidation is an important process in materials science. Silicon oxidation is particularly relevant for electronic device fabrication, but it also provides a model system. We report here the use of in-situ TEM for the examination of the microstructural details of the oxidation process.

scholarly journals Recent Advances in the Fabrication and Environmental Science Applications of Cellulose Nanofibril-Based Functional Materials

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5390
Author(s):  
Lianming Zhang ◽  
Lei Guo ◽  
Gang Wei
Keyword(s):  
Environmental Science ◽  
Materials Science ◽  
Organic Dyes ◽  
Low Cost ◽  
Cellulose Nanofibrils ◽  
Three Dimensional ◽  
Functional Materials ◽  
Building Blocks ◽  
Research Field ◽  
Practical Applications

Cellulose is one of the important biomass materials in nature and has shown wide applications in various fields from materials science, biomedicine, tissue engineering, wearable devices, energy, and environmental science, as well as many others. Due to their one-dimensional nanostructure, high specific surface area, excellent biodegradability, low cost, and high sustainability, cellulose nanofibrils/nanofibers (CNFs) have been widely used for environmental science applications in the last years. In this review, we summarize the advance in the design, synthesis, and water purification applications of CNF-based functional nanomaterials. To achieve this aim, we firstly introduce the synthesis and functionalization of CNFs, which are further extended for the formation of CNF hybrid materials by combining with other functional nanoscale building blocks, such as polymers, biomolecules, nanoparticles, carbon nanotubes, and two-dimensional (2D) materials. Then, the fabrication methods of CNF-based 2D membranes/films, three-dimensional (3D) hydrogels, and 3D aerogels are presented. Regarding the environmental science applications, CNF-based nanomaterials for the removal of metal ions, anions, organic dyes, oils, and bio-contents are demonstrated and discussed in detail. Finally, the challenges and outlooks in this promising research field are discussed. It is expected that this topical review will guide and inspire the design and fabrication of CNF-based novel nanomaterials with high sustainability for practical applications.

In Situ Tem Study of Amorphous to Crystalline Transformation in R-Fe-B Ribbons

1991 ◽  
Vol 232 ◽  
Author(s):  
Y. J. Zhang ◽  
Y. Z. Wang ◽  
G. C. Hadjipanayis
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Building Blocks ◽  
In Situ Tem ◽  
Local Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Unit Structure ◽  
Transmission Electron

ABSTRACTThe amorphous-crystalline transformation in R-Fe-B ribbons was studied in situ in a transmission electron microscope (TEM) and with X-ray diffraction. Metastable phases of α-Fe(R) and Fe3B were found to form during crystallization before the final R2Fe14B phase is formed. The Fe3B phase is believed to be important for the formation of the 2:14:1 phase because its “local unit structure” is one of the basic building blocks in the 2:14:1 unit cell.

scholarly journals Ultrastructural histochemistry in biomedical research: Alive and kicking

2018 ◽  
Vol 62 (4) ◽  
Author(s):  
Manuela Malatesta
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Biomedical Research ◽  
Materials Science ◽  
Light And Electron Microscopy ◽  
Research Field ◽  
Molecular Techniques ◽  
High Resolution Images ◽  
Biological Environment

The high-resolution images provided by the electron microscopy has constituted a limitless source of information in any research field of life and materials science since the early Thirties of the last century. Browsing the scientific literature, electron microscopy was especially popular from the 1970’s to 80’s, whereas during the 90’s, with the advent of innovative molecular techniques, electron microscopy seemed to be downgraded to a subordinate role, as a merely descriptive technique. Ultrastructural histochemistry was crucial to promote the Renaissance of electron microscopy, when it became evident that a precise localization of molecules in the biological environment was necessary to fully understand their functional role. Nowadays, electron microscopy is still irreplaceable for ultrastructural morphology in basic and applied biomedical research, while the application of correlative light and electron microscopy and of refined ultrastructural histochemical techniques gives electron microscopy a central role in functional cell and tissue biology, as a really unique tool for high-resolution molecular biology in situ.

In Situ TEM Study of DNA/Gold Nanoparticles in Liquid Environment

1999 ◽  
Vol 5 (S2) ◽  
pp. 340-341
Author(s):  
W.-A Chiou ◽  
R. C. Mucic ◽  
A. Ishikawa ◽  
H. Konishi ◽  
K. Fukushima ◽  
...  
Keyword(s):  
Au Nanoparticles ◽  
High Vacuum ◽  
Functional Materials ◽  
Building Blocks ◽  
Au Nanoparticle ◽  
Natural State ◽  
In Situ Tem ◽  
Liquid Environment ◽  
Colloidal Au

In recent years the assembly of nanometer sized building blocks into two- and three-dimentional structures and functional materials has been an extremely active area of scientific research. A new class of materials, the DNA/nanoparticle hybrid materials and assemblies, which might have useful electrical, optical and structural properties, have been developed at Northwestern University. While characterizing particle morphology (size and shape) by subjecting it to the high vacuum environment in an electron microscope, the structure may have changed drastically from its natural state. The study of morphology of these DNA/Au nanoparticles in the liquid state was thus undertaken to further our understanding of the dynamics of the nanoparticles in a specific environment. This paper presents an in-situ observation of DNA/Au nanoparticle assembles in liquid media using environmental TEM.Experiments were carried out with citrate-stabilized colloidal Au particles averaging 8 and 31 nm in diameter. Colloidal Au nanoparticles were obtained from a commercial source. 8 nm particles were modified with propylthiol-capped oligonucleotide, 3’HS(CH2)3-O(O)P(O)O-ATG-CTC-AAC-TCT, 1,whereas the 31 nm particles were modified with hexlylthiol-capped oligonucleotide, 3’TAG-GAC-TTA-CGC-O(O)P(O )O-(CH2)6SH, 2.

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