scholarly journals Synthesis of Lead Nanoparticles by Aspergillus Species

2012 ◽  
Vol 61 (1) ◽  
pp. 61-63 ◽  
Author(s):  
K.V. PAVANI ◽  
N. SUNIL KUMAR ◽  
B.B. SANGAMESWARAN
Keyword(s):  
Electron Microscopy ◽  
Size Range ◽  
Natural Process ◽  
Fungal Strain ◽  
Aspergillus Species ◽  
Material Synthesis ◽  
Green Technologies ◽  
Transmission Electron ◽  
20 Nm ◽  
Scanning Electron

In the context of the current demand to develop green technologies in material synthesis, a natural process in the synthesis of lead particles by Aspergillus species to suit such technology is reported. The fungal strain was grown in medium containing different concentrations of lead (0.2-1.5 mM) to determine its resistance to heavy metals. The organism was found to utilize some mechanism and accumulate lead particles outside and inside the cell. The extracellular presence of lead particles in the range of 1.77-5.8 microm was characterized by scanning electron microscopy. The presence of particles of lead in the 5-20 nm size range was found on the cell surface, in the periplasmic space and in the cytoplasm and was analyzed by transmission electron microscopy.

A Facile Fynthesis of ZnS Nanostructures via Liquid-Solid Reactions

2014 ◽  
Vol 979 ◽  
pp. 184-187
Author(s):  
Weerachon Phoohinkong ◽  
Thitinat Sukonket ◽  
Udomsak Kitthawee
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Inorganic Salts ◽  
Chloride Salt ◽  
X Ray ◽  
Commercial Grade ◽  
Transmission Electron ◽  
Salt Addition ◽  
20 Nm ◽  
Scanning Electron

Zinc sulfide (ZnS) nanostructures are important materials for many technologies such as sensors, infrared windows, transistors, LED displays, and solar cells. However, many methods of synthesizing ZnS nanostructures are complex and require expensive equipment. In this study, a liquid-solid chemical reaction without surfactant was used to synthesize ZnS at room temperature. In addition, commercial grade zinc oxide (ZnO) particles were used as a precursor. The effect of the addition of acids and inorganic salts were investigated. The products were characterized by field emission scanning electron microscopy (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The results show that the nanoparticles of ZnS were obtained in hydrochloric acid and acetic acid addition. The diameters were in the range of 10 to 20 nm and 50 to 100 nm, respectively. In the case of a sodium chloride salt addition, a ZnS structure was obtained with a particle size of approximately 5 nm and a flake-like morphology.

Synthesis and Thermal Stability of Nontransformable Tetragonal (ZrO2)0.96(REO1.5)0.04 (Re=Sc3+, Y3+) Nanocrystals

2013 ◽  
Vol 334-335 ◽  
pp. 60-64 ◽  
Author(s):  
Mohammad Reza Loghman-Estark ◽  
Reza Shoja Razavi ◽  
Hossein Edris
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray ◽  
Transmission Electron ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Scanning Electron

Scandia, yttria doped zirconia ((ZrO2)0.96(REO1.5)0.04(RE=Sc3+, Y3+)) nanoparticles were prepared by the modified sol-gel method. The microstructure of the products was characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Thermal stabillity of SYSZ nanocrystals were also investigated. The SYSZ nanocrystals synthesized with EGM:Zr+4mole ratio 4:1, calcined at 700°C, have average diameter of ~20 nm.

Nanoporous Ni and Ni-Cu Fabricated by Dealloying

2009 ◽  
Vol 1228 ◽  
Author(s):  
Masataka Hakamada ◽  
Yasumasa Chino ◽  
Mamoru Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Noble Metals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Difference ◽  
20 Nm ◽  
Good Workability ◽  
Scanning Electron

AbstractMetallic nanoporous architecture can be spontaneously attained by dealloying of a binary alloy. The nanoporous architecture can be often fabricated in noble metals such as Au and Pt. In this study, nanoporous Ni, Ni-Cu are fabricated by dealloying rolled Ni-Mn and Cu-Ni-Mn alloys, respectively. Unlike conventional Raney nickel composed of brittle Ni-Al or Cu-Al intermetallic compounds, the initial alloys had good workability probably because of their fcc crystal structures. After the electrolysis of the alloys in (NH4)2SO4 aqueous solution, nanoporous architectures of Ni and Ni-Cu with pore and ligament sizes of 10–20 nm were confirmed by scanning electron microscopy and transmission electron microscopy. X-ray diffraction analyses suggested that Ni and Cu atoms form a homogeneous solid solution in the Ni-Cu nanoporous architecture. The ligament sizes of nanoporous Ni and Ni-Cu were smaller than that of nanoporous Cu, reflecting the difference between diffusivities of Ni and Cu at solid/electrolyte interface. Ni can reduce the pore and ligament sizes of resulting nanoporous architecture when added to initial Cu-Mn alloys.

scholarly journals Physical Properties and Precipitate Microstructures of Cu-Hf Alloys at Different Processing Stages

Scanning ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Mingmao Li ◽  
Leqing Zhang ◽  
Mingbiao Zhu ◽  
Hang Wang ◽  
Haigen Wei
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Physical Properties ◽  
Slow Rate ◽  
Softening Temperature ◽  
Transmission Electron ◽  
20 Nm ◽  
Scanning Electron

The microstructural evolution and hardness and physical properties of a Cu-Hf alloy at the different processing stages were investigated using hardness, conductivity and tensile measurements, metallographic microscopy, scanning electron microscopy, and transmission electron microscopy. The results reveal that the electrical conductivity of these alloys was above 80% IACS after aging at 450°C, and the hardness and conductivity of the Cu-0.9Hf alloy were 180 HV0.5 and 80% IACS, respectively. The softening temperature of the Cu-0.15Hf alloy is 525°C, and the softening temperature of Cu-0.4Hf and Cu-0.9Hf alloys is 550°C. The precipitated Hf-containing phase exhibited a short rod-like structure, the size of which increased with aging time at a slow rate and resulted in the size of ~20 nm after aging at 450°C for 300 min.

Microstructure of Ti6Al4V after Ultrasound-Aided Deep Rolling

2013 ◽  
Vol 661 ◽  
pp. 141-144
Author(s):  
Li Li ◽  
Zhen Yu Fu ◽  
Tao Li ◽  
Jin Jun Liu ◽  
Zheng Yu Tian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Microstructure ◽  
Deep Rolling ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ti6al4v Titanium Alloy ◽  
Transmission Electron ◽  
20 Nm ◽  
Scanning Electron

Ti6Al4V titanium alloy was treated by an ultrasound-aided deep rolling (UADR) process. The microstructure of UADR treated specimen was observed via using scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results show that ultrasound-aided deep rolling produced nanocrystallized microstructure of grain scale typically less than 20 nm on the immediate surface of Ti6Al4V. A nanometer to submicron gradient structured layer penetrating to a depth of about 150 μm was formed after UADR treatment. The above improvements of surface microstructure of the UADR treated specimen is believed to be beneficial to its anti-fatigue performance.

scholarly journals Green Synthesis of Stable Nanocomposites Containing Copper Nanoparticles Incorporated in Poly-N-vinylimidazole

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3212
Author(s):  
Alexander S. Pozdnyakov ◽  
Artem I. Emel’yanov ◽  
Svetlana A. Korzhova ◽  
Nadezhda P. Kuznetsova ◽  
Yuliya I. Bolgova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Polymer Nanocomposites ◽  
Polymer Matrix ◽  
Copper Nanoparticles ◽  
Copper Content ◽  
Uv Spectroscopy ◽  
Spherical Shape ◽  
Transmission Electron ◽  
20 Nm ◽  
Scanning Electron

New stable nanocomposites with copper nanoparticles (CuNPs) in a polymer matrix have been synthesized by green chemistry. Non-toxic poly-N-vinylimidazole was used as a stabilizing polymer matrix and ascorbic acid was used as a reducing agent. The polymer CuNPs nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic absorption spectroscopy (AAS), and thermogravimetric analysis (TGA). It was shown, using the dynamic light scattering (DLS) method, that the hydrodynamic diameters of nanocomposites depend on the CuNPs content and are in an associated state in an aqueous medium. The copper content in nanocomposites ranges from 1.8 to 12.3% wt. The obtained polymer nanocomposites consist of isolated copper nanoparticles with a diameter of 2 to 20 nm with a spherical shape.

A Comparative Analysis of Structural Defect Formation in Si+ Implanted and then Plasma Hydrogenated and in H+ Implanted Crystalline Silicon

2007 ◽  
Vol 131-133 ◽  
pp. 309-314 ◽  
Author(s):  
Heidi Nordmark ◽  
Alexander G. Ulyashin ◽  
John Charles Walmsley ◽  
Randi Holmestad
Keyword(s):  
Electron Microscopy ◽  
Plasma Treatment ◽  
Defect Formation ◽  
Crystalline Silicon ◽  
Implantation Dose ◽  
Transmission Electron ◽  
Microcrack Formation ◽  
20 Nm ◽  
Silicon Implantation ◽  
Scanning Electron

Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) have been used to compare hydrogen defects formed in p doped [001] oriented Cz silicon samples which are H+ plasma treated , H+ implanted or Si+ implanted + H+ plasma treated. Samples were studied as processed and after annealing at 250°C, 450°C and 600°C. It is found that 1 hour H+ plasma treatment at 250°C produces a low density of large defects (~100 nm) in prefered {111} plans close to the surface. H+ implantation at a dose of 3x1016 cm-2 produces high density of small (~ 20 nm) mostly {100} platelets that after 1 hour annealing at 450°C result in microcrack formation. Lower H+ implantation doses form very few microcracks at this temperature. Silicon implantation with a dose of 1015 cm2 followed by 1 hour H+ plasma treatment at 250°C and 1 hour annealing at 450°C produces similar microstructure and microcracks as the 3x1016 cm2 H+ implantation dose.

scholarly journals Biosynthesis of Gold Nanoparticles (AuNPs) by Diopatra claparedii Grube, 1878 (Polychaeta: Onuphidae) and Its Antibacterial Activity

2021 ◽  
Vol 50 (5) ◽  
pp. 1309-1320
Author(s):  
Chong Huai Piong ◽  
Noor Aniza Harun ◽  
Angeline Ung Ee Pei ◽  
Mohammad Asyraf Adhwa Masimen ◽  
Wan Iryani Wan Ismail ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Size Range ◽  
Salmonella Typhi ◽  
Atmospheric Conditions ◽  
Environmental Friendly ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Staphyloccus Aureus ◽  
Scanning Electron

Gold nanoparticles (AuNPs) have gained attention as it possesses outstanding physicochemical properties, and utilised in variety of applications especially in biomedical and pharmaceutical. Majorly, AuNPs are produced by conventional methods (chemical and physical). However, these methods bring several drawbacks such as toxic, hazardous, low yield and non-environmental friendly. Hence, biosynthesis of AuNPs that compliance with ‘greener’ approach becomes vitals. In this study, marine tube worm of Diopatra claparedii (polychaetes) was employed as reducing agent in the biosynthesis of AuNPs. The biosynthesised of AuNPs by D. claparedii extract was successfully prepared under ambient temperature and normal atmospheric conditions. The formation of AuNPS was confirmed by the appearance of surface Plasmon resonance (SPR) bands around 540 to 560 nm characterized by UV-Vis spectroscopy. Scanning electron microscopy (SEM) showed that the AuNPs are mostly in agglomerated spherical like shapes with size ranging from 100 to 400 nm. Meanwhile, transmission electron microscopy (TEM) showed that the particles are in the size range from 25 to 60 nm, also mainly form in spherical like shape. The particle size of AuNPs in a range of 50-100 nm was showed by dynamic light scattering (DLS). Fourier-transform infrared (FTIR) spectrum of D. claparedii extract indicated the existence of several functional groups. Biosynthesised AuNPs also successfully gave inhibition on bacterial growth (Staphyloccus aureus, S. epidermidis, Escheratia coli, Salmonella typhi) through antibacterial assessment.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

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