Magneto-Optics of Cobalt and Nickel Nanoparticles Implanted in SiO2: Comparative Study

2014 ◽  
Vol 215 ◽  
pp. 214-217 ◽  
Author(s):  
Dmitriy A. Petrov ◽  
Irina S. Edelman ◽  
Ruslan D. Ivantsov ◽  
Sergey M. Zharkov ◽  
Andrey L. Stepanov

Co and Ni nanoparticles were fabricated in fused silica plates by ion implantation technique. Electron microscopy showed the nanoparticles to be of spherical shape. Magnetic circular dichroism (MCD) was investigated in the spectral range 1.2 - 4.2 eV in a field of about 3 kOe. MCD spectra are considerably different from the spectra of thin nickel and cobalt films. MCD spectra for Ni nanoparticles are associated with surface plasmon resonance.

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 97
Author(s):  
Suresh V. Chinni ◽  
Subash C. B. Gopinath ◽  
Periasamy Anbu ◽  
Neeraj Kumar Fuloria ◽  
Shivkanya Fuloria ◽  
...  

The present study was planned to characterize and analyze the antimicrobial activity of silver nanoparticles (AgNP) biosynthesized using a Coccinia indica leaf (CIL) ethanolic extract. The present study included the preparation of CIL ethanolic extract using the maceration process, which was further used for AgNP biosynthesis by silver nitrate reduction. Biosynthetic AgNPs were characterized using UV–Visible spectrometry, zeta potential analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) spectrometry. The biogenic AgNP and CIL extracts were further investigated against different bacterial strains for their antimicrobial activity. The surface plasmon resonance (SPR) signal at 425 nm confirmed AgNP formation. The SEM and TEM data revealed the spherical shape of biogenic AgNPs and size in the range of 8 to 48 nm. The EDX results verified the presence of Ag. The AgNPs displayed a zeta potential of −55.46 mV, suggesting mild AgNP stability. Compared to Gram-positive bacteria, the biogenic AgNPs demonstrated high antibacterial potential against Gram-negative bacteria. Based on the results, the current study concluded that AgNPs based on CIL extract have strong antibacterial potential, and it established that AgNP biosynthesis using CIL ethanol extract is an effective process.


2009 ◽  
Vol 620-622 ◽  
pp. 699-702
Author(s):  
In Churl Cho ◽  
Yong Kap Park ◽  
Yong Choi

A unique method, so called, hydro-thermal synthetic method was applied to produce nano-sized inorganic blue (Y2SiO5:Ce) and red (Y2O2S:Eu+3) emitting phosphors. Electron microscopy revealed that the nano-sized emitting phosphor particles have spherical shape with 23-50nm in size. The particles can effectively change ultraviolet rays of 1-390 nm to infrared rays of 750nm -1mm, which are suitable to promote the growth of plants. The principle excitation and emitting spectrum of the red phosphor in 590-700 nm emitting spectrum were in the region of 308nm and 617nm, respectively, whereas, those of the blue phosphor in 420-470nm emitting spectrum were in the region of 254nm and 464nm, respectively. The addition of 0.1-0.2 wt% of the 2:1 mixed red and blue powders to a film showed the maximum emitting intensity of 537x1000 count/sec.


2009 ◽  
Vol 114 (1) ◽  
pp. 89-92 ◽  
Author(s):  
Alexandre Geissler ◽  
Maoshuai He ◽  
Jean-Michel Benoit ◽  
Pierre Petit

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
W. S. Zhang ◽  
J. G. Zheng ◽  
W. F. Li ◽  
D. Y. Geng ◽  
Z. D. Zhang

The boron-nitride (BN) nanocages are synthesized by nitrogenation of amorphous boron nanoparticles at 1073 K under nitrogen and ammonia atmosphere. The BN nanocages exhibit a well-crystallized feature with nearly pentagonal or spherical shape, depending on their size. High-resolution transmission electron microscopy studies reveal that they are hollow nanocages. The growth mechanism of the BN nanocages is proposed.


2013 ◽  
Vol 307 ◽  
pp. 352-357
Author(s):  
Kai Fan ◽  
Feng Liu ◽  
Bao Quan Fu ◽  
Wen Zhong Luo ◽  
Yao He Zhou

In order to study the precipitaion of Ni3Si particle in undercooled Ni-Si alloy, calorimetric analyses were carried out using non-isothermal measurements by DSC. The scanning electron microscopy (SEM) and the transmission electron microscopy (TEM) measurements were used to describe qualitatively and quantitatively the precipitate microstructures. The non-isothermal DSC thermograms exhibited one reaction peaks and it indicated that the precipitation process is an exothermic reaction. The evolution for the precipitate was obtained in the as-solidified Ni-Si alloy subjected to DT=195K, meanwhile, the precipitate size was found increased with decreased heating rate in the TEM images. The largest precipitate size was about 120nm, and the precipitates still kept spherical shape. Model prediction for the precipitation of Ni3Si particle has been performed. Good agreement with experimental data has been achieved


2017 ◽  
Vol 7 (15) ◽  
pp. 3339-3347 ◽  
Author(s):  
Hristiyan A. Aleksandrov ◽  
Nikolaos Pegios ◽  
Regina Palkovits ◽  
Kalin Simeonov ◽  
Georgi N. Vayssilov

Monoatomic C species remain separated in the subsurface regions of small Ni nanoparticles, while in larger particles, carbon chains are formed, which can be considered as precursors for coke or graphene formation.


Author(s):  
Zahra Salehi ◽  
Azam Fattahi ◽  
Ensieh lotfali ◽  
Abdolhassan Kazemi ◽  
Ali Shakeri-Zadeh ◽  
...  

Purpose: The present study was performed to examine whether caspofungin-coated gold nanoparticles (CAS-AuNPs) may offer the right platform for sensitivity induction in resistant isolates. Methods: For the purpose of the study, a total of 58 archived Candida species were enrolled in the research. The identification of Candida spp. was performed using polymerase chain reaction-restriction fragment length polymorphism and HWP1 gene amplification approaches. The conjugated CAS-AuNPs were synthesized and then characterized using transmission electron microscopy (TEM) and Zetasizer system to determine their morphology, size, and charge. Furthermore, the efficacy of CAS, CAS-AuNPs conjugate, and AuNPs against Candida spp. was assessed based on the Clinical and Laboratory Standards Institute M60. Finally, the interaction of CAS-AuNPs with Candida element was evaluated via scanning electron microscopy (SEM). Results: According to the TEM results, the synthesized CAS-AuNPs had a spherical shape with an average size of 20 nm. The Zeta potential of CAS-AuNPs was -38.2 mV. Statistical analyses showed that CAS-AuNPs could significantly reduce the minimum inhibitory concentration against C. albicans (P=0.0005) and non-albicans Candida (NAC) species (P<0.0001). All isolates had a MIC value of ≥ 4 µg/ml for CAS, except for C. glabrata. The results of SEM analysis confirmed the effects of AuNPs on the membrane and cell wall structure of C. globrata exposed to CAS-AuNPs, facilitating the formation of pores on the cell wall and finally cell death. Conclusion: The findings revealed that CAS-AuNPs conjugates had significant antifungal effects against Candida spp. through the degradation of the membrane and cell wall integrity. Therefore, it can be concluded that the encapsulation of antifungal drugs in combination with NPs not only diminishes side effects but also enhances the effectiveness of the medications.


2021 ◽  
Vol 63 (9) ◽  
pp. 1340
Author(s):  
Н.А. Иванов ◽  
С.А. Небогин ◽  
С.С. Колесников ◽  
Л.И. Брюквина

It is investigated the thermal etching of LiF and MgF2 crystals with cobalt and nickel impurities by means of scanning electron microscopy and atomic force microscopy with using decorating. It is shown that impurity inclusions leave the crystal from dislocations. The differences between of thermal etching in vacuum and air atmosphere take place. The crystallographic oriented terraced etch pits are formed after exit of impurities from dislocations. The square thermal etch pits are formed after thermal etching at 750°C in air. The surface impurity nanoscale film is formed at thermal etching. The oxidation of surface impurities observed at thermal etching in air atmosphere or in residual air atmosphere.


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