This document outlines a study on the synthesis and characterization of doped Cr2O3 nanoparticles. It will investigate doping Cr2O3 nanoparticles with elements like Fe, ZnO, and Co using microwave synthesis and sol-gel methods. Characterization of the structural, electrical, and optical properties of the doped nanoparticles will be conducted using techniques like XRD, SEM, and FTIR. The study aims to better understand how doping affects the properties of Cr2O3 nanoparticles compared to the bulk material. A timeline is provided outlining the literature review, experimental work, characterization, drafting and final submission over a 5 month period.
All the applications of ferrites is described in this presentation very briefly and presciously.
It would surely help you.
Please share it with your friends also.
All the applications of ferrites is described in this presentation very briefly and presciously.
It would surely help you.
Please share it with your friends also.
It's simple to understand the synthesis. Hydrothermal method is a chemical reaction in water in a sealed pressure vessel, which is in fact a type of reaction at both high temperature and pressure.
With the increasing researches in the field of nanotechnology, various nanoparticles have become a source of interest among the nano technologists because of their great properties, like the optical properties of Cadmium Sulfide Nanoparticles are amazing and also easy to synthesize, but to make sure its quality it is equally essential to make out characterize it, this file will do the same in a lucid way!!
the presentation gives brief description about magnetic nanoparticles, types of magnetic nanoparticles, magnetic nanocomposite and application of magnetic nanoparticles.
K2O - CdO - B2O3 – SiO2glasses containing different concentrations of MnO2 have been prepared. The Physical properties of the glasses are studied from their density. The studies have been analysed in the light of different oxidation states of manganese ion with the aid of the data from optical absorption. The analysis shows that manganese ions exist mainly in Mn2+ state, occupy tetrahedral positions and increase the insulating strength of the glass if MnO2 is present in smaller concentrations.
It's simple to understand the synthesis. Hydrothermal method is a chemical reaction in water in a sealed pressure vessel, which is in fact a type of reaction at both high temperature and pressure.
With the increasing researches in the field of nanotechnology, various nanoparticles have become a source of interest among the nano technologists because of their great properties, like the optical properties of Cadmium Sulfide Nanoparticles are amazing and also easy to synthesize, but to make sure its quality it is equally essential to make out characterize it, this file will do the same in a lucid way!!
the presentation gives brief description about magnetic nanoparticles, types of magnetic nanoparticles, magnetic nanocomposite and application of magnetic nanoparticles.
K2O - CdO - B2O3 – SiO2glasses containing different concentrations of MnO2 have been prepared. The Physical properties of the glasses are studied from their density. The studies have been analysed in the light of different oxidation states of manganese ion with the aid of the data from optical absorption. The analysis shows that manganese ions exist mainly in Mn2+ state, occupy tetrahedral positions and increase the insulating strength of the glass if MnO2 is present in smaller concentrations.
Implant dentistry is growing well in Myanmar. As a faculty member and a dentist who is specialized in Prosthetic Dentistry including Dental Implant, the presenter notice that we have to move another one step...usage of bio-material... in clinical practice.
Synthesis and charaterization of la1 x srxmno3 perovskite nanoparticlesMai Trần
In recent times perovskite materials are extensively studied and have attracted much attention because they exhibit interesting the properties, showing potential applications in commercial, technical and biomedical. In Vietnam, perovskite materials be of interest research and applications are strong but with major research direction is to go deep into the electrical properties and the magnetic properties. The Lanthanum Strontium manganite is a perovskite-based crystal-structured ceramic material with the formula of La1-xSrxMnO3, where x describes the doping ratio. It has attracted much attention due to its good magnetic, electrical, and catalytic properties and is becoming an attractive possibility material in several biomedical applications, particularly with nano-size. In industry, this material is commonly used in as a cathode material in commercially produced solid oxide fuel cells. In this thesis, we present the Perovskite nanoparticles La1-xSrxMnO3 were successfully synthesized of the nanosize La1-xSrxMnO3 at x = 0; 0.1; 0.2; 0.3 and 0.4 which prepared by a modified sol-gel method. Structure and magnetic properties of them were systematically investigated in dependence on doped Sr ratio x. The structure was investigated by XRD and show slightly changed but magnetic properties varied strongly with changing the doping ratio x. Magnetic properties of samples were studied by Vibrating Sample Mode of Physical Properties Measurement System show at the room temperature, the samples show superparamagnetic properties with high saturated magnetization MS of 57 emu/g which strongly dependents on the doped Sr ratio x.
Plenary lecture of the XIV SBPMat Meeting, given by Prof. Paul Ducheyne (University of Pennsylvania, USA) on September 29, 2015, in Rio de Janeiro (Brazil).
Synthesis and Elastic Studies of Lead Boro-Tellurite Glass SystemSidek Aziz
Synthesis and Elastic Studies of Lead Boro-Tellurite Glass System presented Seminar Kebangsaan Aplikasi Sains dan Matematik 29-30 October 2013 ata UTHM Johor
A dental implant (also known as an endosseous implant or fixture) is a surgical component that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, facial prosthesis or to act as an orthodontic anchor. The basis for modern dental implants is a biologic process called osseointegration where materials, such as titanium, form an intimate bond to bone.
We are going to discuss the four Biomaterials and their Dental Applications, the Advantages and Disadvantages of each Material.
Study of Microstructural, Electrical and Dielectric Properties of La0.9Pb0.1M...Scientific Review SR
The present work studies the microstructural and electrical properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 ceramics synthesized by solid-state route method. Microstructure and elemental analysis of both samples were carried out by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) method, respectively. Phase analysis by X-ray diffraction (XRD) indicated formation of single phase distorted structure. The XRD data were further analyzed by Rietveld refinement technique. Raman analysis reveals that Y atom substitutes La site into the LPMO with shifting of phonon modes. The temperature variation of resistivity of undoped and Y-doped La0.9Pb0.1MnO3 samples have been investigated. The electrical resistivity as a function of temperature showed that all samples undergo an metal-insulator (M-I) transition having a peak at transition temperature TMI. Y-doping increases the resistivity and the metal-insulator transition temperature (TMI) shifts to lower temperature. The temperature-dependent resistivity for temperatures less than metal-insulator transition is explained in terms the quadratic temperature dependence and for T > TMI, thermally activated conduction (TAC) is appropriate. Variation of frequency dispersion in permittivity and loss pattern due to La-site substitution in LPMO was observed in the dielectric response curve.
Optical and Impedance Spectroscopy Study of ZnS NanoparticlesIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Calculation of Optical Properties of Nano ParticlePHYSICS 5535- .docxRAHUL126667
Calculation of Optical Properties of Nano Particle
PHYSICS 5535- Optical Properties Matter-Spring 2017
Raznah Yami
Outline
1. Introduction: this part gives a precise overview of the whole paper. It begins by illustrating a brief introduction and importance of Nano Particles and the theoretical approaches used for their calculation.
2. Main idea: this section provides a step-by-step in-depth analysis of recently developed theories the calculation of optical properties of nanoparticles. It also provides calculation and equations employed these approaches.
2.1 Optical Properties of Nanoparticles: this section talks about the basics principles and governing the optical behavior of Nano particles and provides in-depth knowledge of different phenomena observed while dealing with optical properties of Nano particles.
2.2 Mie-Theory: the research provides exhaustive information the study optical properties of nanoparticles using Mie theory. This research focuses on Mie theory for the calculation of optical properties of Nano particle according to which we can calculate the place of surface Plasmon resonance in optical spectra of metallic spherical nanoparticle.
2.3 Discrete Dipole Approximation method: this section enumerates sufficient information about the calculation of absorption and scattering efficiencies and optical resonance wavelengths for three commonly used classes of nanoparticles: gold Nano spheres, silica-gold Nano shells, and gold Nano rods and we examine the magneto-optical scattering from nanometer-scale structures using a discrete dipole approximation.
3. Conclusion: This section provides a summary of the most important points, which presents an overview of the practical application and calculation methods of optical properties of Nano particles talking about core principles, which therefore explain the behavior exhibited by nanoparticles.
List of figures:
Figure 1: Localized surface Plasmon resonance ,resulting from the collective oscillations of delocalized electrons in response to an external electric field
Figure 2: Absorption spectra of semiconductor nanoparticles of different diameter. Right-nanoparticles suspended in solution.
Figure 3: Comparison of absorbance along increasing wavelength between Nano GaAs (7-15 nm) and Bulk GaAs showing an apparent blue shift
Figure 4: Showing the effect of blue shift because of quantum confinement as the wavelength shifts from 1100 nm to 2000 nm when we move from particle size of 9nm to parcile size of 3 nm.
Figure 5: Emission spectra of several sizes of (Cdse) Zns core-shell quantum dots.
Figure 6: The optical spectra and transmission electron micrographs for the particles in vials 1–5 are also shown. Scale bars in micrographs are all 100 nm
Figure7: Shows the effect of varying relative core and shell thickness of gold Nano Shells, there is an apparent blue shift as the frequency increases
References:
1. . P. S. Per ...
Study of highly broadening Photonic band gaps extension in one-dimensional Me...IOSR Journals
In this paper, we show theoretically that the reflectance spectra of one dimensional multilayer metal-organic periodic structure (1D MOPS) can be enhanced due to the addition of the organic constituents. We have used simple transfer matrix method to calculate the absorption, transmittance and reflectance of the 1D MOPS systems. The organic component like N,N’-bis-(1-naphthyl)-N,N’diphenyl-1; 1biphenyl-4; 4diamine (NPB) absorbs the light in ultra-violet, visible and infrared electromagnetic region and the structure with Ag-metal also having the tendency to absorb the light by the plasmaonic action and their refractive can be calculated from Drude equation. The reflectance spectra of multilayer 1D MOPS containing a variable number periodic of Ag/N,N’-bis-(1-naphthyl)-N,N’diphenyl-1; 1biphenyl-4; 4diamine (NPB) structure are calculated taking optical constant of NPB and Ag. The optical band gap and reflectance spectra of 1D MOPS of the considered structure is obtained in the visible and near infrared regions either with the variation of the metal layer thickness or thickness of the organic layer. From the results under investigation through TMM, tunability in the optical band gap was observed either change in thickness of the other layer 1/ or 2 or the angle of the incident. Due to optical absorption of the light in the different region of electromagnetic spectrum due to either N,N’-bis-(1-naphthyl)-N,N’diphenyl-1; 1biphenyl-4; 4diamine (NPB) or silver metal, the optical band gap of 1DMOPS shows the shift of band edges of λL and λR from ultra-violet to visible and the infrared with change the optical constant.
Effect of calcination on the electrical properties and quantum confinement of...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Effect of calcination on the electrical properties and quantum confinement of...eSAT Journals
Abstract Fe2O3 nanoparticles have been prepared by a simple solvothermal method using a domestic microwave oven. X-ray powder diffraction measurement indicates the amorphous nature of the as-prepared sample. Calcined samples were obtained by annealing the as-prepared sample at different temperatures, viz. 400, 500, 600 and 700oC. Transmission electron microscopic images indicate that all the five samples are spherical in shape. AC electrical measurements were carried out on pelletized samples by the parallel plate capacitor method at various temperatures ranging from 40-130oC and frequencies ranging from 100 Hz -1 MHz. Results indicate low AC electrical conductivities and consequently show the occurrence of nano confined states. The exciton Bohr radii obtained from the dielectric constant values at 40oC temperature and 1 kHz frequency are 41.8, 54.8, 55.3, 56.3 and 27.0 respectively for the as-prepared sample and samples calcined at 400, 500, 600 and 700oC which indicate a strong quantum confinement effect. The impedance spectra observed exhibit non-ideal behavior. Keywords: Semiconductors, Magnetic materials, Nanoparticles, Electrical properties
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Synthesis and Characterisation of Copper Oxide nanoparticlesIOSR Journals
Cupric oxide (CuO) nanoparticles were prepared by the chemical route by calcinations at a higher temperature from 300oC to 400 oC. For the comparison transmission electron microscopy (TEM) and x-ray diffraction (XRD) measurements were made through JCPDS. There is good agreement between data produced by spectroscopy and the microscopic measurements.
Study of magnetic and structural and optical properties of Zn doped Fe3O4 nan...Nanomedicine Journal (NMJ)
Objective(s):
This paper describes synthesizing of magnetic nanocomposite with co-precipitation
method.
Materials and Methods:
Magnetic ZnxFe3-xO4 nanoparticles with 0-14% zinc doping (x=0, 0.025, 0.05, 0.075, 0.1 and 0.125) were successfully synthesized by co-precipitation method. The prepared zinc-doped Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and UV-Vis spectroscopy.
Results:
results obtained from X-ray diffraction pattern have revealed the formation of single phase nanoparticles with cubic inverse spinal structures which size varies from 11.13 to 12.81 nm. The prepared nanoparticles have also possessed superparamagnetic properties at room temperature and high level of saturation magnetization with the maximum level of 74.60 emu/g for x=0.075. Ms changing in pure magnetite nanoparticles after impurities addition were explained based on two factors of “particles size” and “exchange interactions”. Optical studies results revealed that band gaps in all Zn-doped NPs are higher than pure Fe3O4. As doping percent increases, band gap value decreases from 1.26 eV to 0.43 eV.
Conclusion:
These magnetic nanocomposite structures since having superparamagnetic property
offer a high potential for biosensing and biomedical application.
Similar to Study of doped chromiun oxide nanoparticle (20)
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
1. Study Of Doped Cr2O3 Nanoparticles
By:
Gaurav Kumar Yogesh
Reg. No. CUPB/M.Sc./SBAS/PMS/2013-14/01
Supervisor: Dr. Kamlesh Yadav
(Assistant Professor)
Centre for Physical and Mathematical Sciences
Central University of Punjab, Bathinda
2. Introduction
Nanomaterials
Historic background
Classification of nanoparticles
Method to approach nanoparticle
Properties and application
Gap analysis
Objective
Microwave assisted Synthesis
Observations to be recorded
Time Schedule for M.Sc. Dissertation
References
3. Nanomaterials have dimensions of less than 100 nm and atleast 1 nm.
They have superior properties than bulk.
There are various methods for the synthesis of nanomaterials like sol gel, microwave
synthesis etc.
They can generally be classified as one of two types: engineered or non-engineered
Engineered nanoparticles are intentionally designed and created with physical properties
tailored to meet the needs of specific applications.
Non-engineered nanoparticles are unintentionally generated or naturally produced, such as
atmospheric nanoparticles created during combustions.
4.
5. Historical evidences of use nanoparticles
The Lycurgus cup is from the 4th century AD and was
probably carved in Rome. It appears RED by reflexion and
GREEN by transmission. This technology has been used
during the roman era. Gold and silver were added to glasses.
Fig. http://www.cambridge2000.com/gallery
6.
7. Size effects constitute a peculiar and fascinating aspect of nanomaterials. The effects determined by size
pertain to the evolution of structural, thermodynamic, electronic, spectroscopic, electromagnetic and
chemical features of these finite systems with changing size.
Example: gold nanoparticle.face
LS-FCM University of Bologna
9. 1. Commonly found as the rare minerals Eskolaite, Cr2O3
2. It has rhombohedral structure
3. There are two descriptions of the rhombohedral lattice system.
Hexagonal axes: The unit cell is a = b ≠ c; α = β = 90°, γ = 120°
Rhombohedral axes: This is a primitive unit cell with parameters
a = b = c; α = β = γ ≠ 90°.
Fig. Rhombohedral cell
10. 1.Magnetic properties
Cr2O3 nanoparticle is an antiferromagnet with a Neel temperature TN of 311 K .
Find diverse technological applications in information storage and spintronics.
Surface spins increases as the particle size is decreased.
2. Electrical properties
Cr2O3 is intrinsic semiconductor Whose conductance is independent of oxygen partial pressure at
high temperature (>1273 K).
At lower temperature the oxide is an extrinsic p-type.
Due to the presence of a small amount of unoccupied cr4+ states in the bulk which hope from one
lattice chromium to next at temperature above 623 K.
3. Structural properties
Rhombohedral structure of the material with lattice parameter, a = b= 4.953 Å; c = 13.578 Å,
11. Optical properties arise due to surface Plasmon resonance.
SPR is caused due to the coherent motion of the C.B electrons from one surface of the particle to the
other, upon interaction on electromagnetic radiation.
Decrease in size below the electron mean free path gives rise to the intense absorption of UV- visible
radiation.
Optical excitation of the SPR gives rise to the surface plasmon absorption.
Surface plasmon absorption depends on the size and the shape of the particles.
12. Solar energy thermal collector
Insulating antiferromagnetic material
Tunnel junction barrier
Coating for the passivation of the surface against corrosion
Microelectronics
Sensors
Piezoelectric devices
Coating materials for thermal protection hydrogen storage antimicrobial and antibacterial
activity
Green pigments
13. Synthesis with a sol method by using capping agents to prevent aggregation and control the
size.
Quantum confinement occurs when the electrons motion is limited by the size of the NP.
The electronic energy levels of the particle around the Fermi level are affected only for very
small sizes.
The UV-visible absorption is determined by the surface plasmon resonance, which is size
and shape dependent.
Exhibit a very weak luminescence.
Show valuable catalytic properties, owing to the large surface to mass ratio.
14. There are various ways of preparing nanoparticles:
1. Sol-gel method
2. Microwave synthesis
3. Hydrothermal reaction
4. Arc discharge reaction
For our experiment we use the sol-gel and microwave synthesis methods
15. Microwaves radiation are a form of electromagnetic energy with frequencies in the range
of 300 MHz to 300 GHz.
Interactions between materials and microwaves are based on two specific mechanisms:
dipole interactions and ionic conduction.
In the Dipole interactions the polar ends of a molecule tend to re-orientate themselves and
oscillate in step with the oscillating electrical field of the microwaves. Heat is generated
by molecular collision and friction.
Jimmy. C.Yu.,2004
17. Conductive heat
Heating by convection currents
Slow and energy inefficient process
18. Broad dynamic temperature range up to 300K
Microwave energy can heat the whole sample volume very effectively.
It yields better product in short duration.
Thermal equilibrium is quickly achieved.
The microwave synthesized products were calcined in air to obtain the well-defined crystallographic
phase.
Low energy is required.
Higher chemical yield is obtained.
Microwave synthesis apparatus can be turned off instantly when the reaction mixture reaches the
temperature set point.
Parameters can be controlled excellently.
Safety is the most important feature.
19. Cr2O3 nanoparticles prepared by microwave synthesis and sol gel method is advantageous to
our study as it is time saving and a good morphology can be achieved with the help of this. So
our present study is based on the formation of nanoparticles. The structural, magnetic and
electrical properties will be strongly influenced by the doping of the several element of d block
element such as Fe, ZnO and Co. From the literature survey done so far, very few literature is
available on the synthesis of Cr2O3 nanoparticles by using microwave synthesis method and sol-
gel method.
20. The lattice parameters will be calculated using the plot of X-Ray diffraction.
We can calculate the variation of intensity with the angle of diffraction.
Surface morphology can be calculated using SEM.
Electrical band can be calculated by FTIR
21. The lattice parameters like a, b, c and α, β, γ will be calculated by using x-ray diffraction, also
the graph between intensity and 2θ will be helpful for estimating the variation of intensity with
2θ. The crystallite size can be calculated by using the Debye scherrer’s formula D=
0.9λ/βcosθ, where D is crystallite size, is wavelength of x-rays, is full width at half maximum
and θ is Bragg’s angle.
22. To synthesize the Cr2O3 nanoparticles by using microwave synthesis method and sol gel
method then study the doping effect on the optical, electrical and structural properties of
nanoparticles.
23. Location of Research
We will prepare Cr2O3 nanoparticles by Microwave synthesis and by using Sol-gel technique at
Central University of Punjab. For the characterization of the prepared nanoparticles we have to go
suitable places if university permits.
23
24. As Cr2O3 nanoparticles will be synthesized by microwave assisted synthesis and it is
expected that there will be a change in the properties compared to the bulk.
The Electrical, Structural, Optical will be correlated.
25. Sr. No. Activities January February March April May
1 Literature
survey
2 Experimental
work
3 Characterisati
on
4 Draft
submission
5 Final
submission
26. References
Abdullah, M. M., Rajab, F. M., and Al-Abbas, S. M. (2014). Structural and optical characterization of Cr2O3
nanostructures: Evaluation of its dielectric properties. AIP Advances, 4(2), 027121.
Balouria, Vishal; Singh, A.; Debnath, A. K.; Mahajan, Aman; Bedi, R. K.; Aswal, D. K.; Gupta, S. K., Synthesis
and characterization of sol-gel derived Cr2O3 nanoparticles.
F. Farzaneh and M. Najafi, Synthesis and Characterization of Cr2O3 Nanoparticles with Triethanolamine in Water
under Microwave Irradiation, Received: 17 May 2011 / Revised: 9 January 2012 / Accepted: 15 January 2012
Hung, C. H., Shih, P. H., Wu, F. Y., Li, W. H., Wu, S. Y., Chan, T. S., & Sheu, H. S. (2010). Spin-phonon coupling
effects in antiferromagnetic Cr2O3 nanoparticles. Journal of nanoscience and nanotechnology, 10(7), 4596-4601.
Mohanapandian and Krishnan.,2014 study Effect of Concentration of Ni2+ on the Physio Chemical Properties of
Cr2o3 Nanoparticles
Pei, Z., and Zhang, Y. (2008). A novel method to prepare Cr2O3 nanoparticles.Materials Letters, 62(3), 504-506.
Pei, Z., Xu, H., and Zhang, Y. (2009). Preparation of Cr2O3 nanoparticles via C2H5OH hydrothermal
reduction. Journal of Alloys and Compounds, 468(1), L5-L8.
Zhang, W. S., Bruck, E., Zhang, Z. D., Tegus, O., Li, W. F., Si, P. Z. & Buschow, K. H. J. (2005). Structure and
magnetic properties of Cr nanoparticles and Cr2O3 nanoparticles. Physica B: Condensed Matter,358(1), 332-338.