This document summarizes an experiment to verify the wave-particle duality of electrons using electron diffraction. Electrons are accelerated towards a graphite target, causing a diffraction pattern of concentric rings to appear on a fluorescent screen based on the De Broglie wavelength. The diameters of the rings were measured at different voltages and found to match closely with theoretical wavelengths calculated using De Broglie's equation, providing evidence that electrons exhibit both wave and particle properties.
Glow Discharge Mass Spectrometer: A brief Introduction.pptxReshma Kuppili
Glow Discharge Mass Spectrometer has gained popularity among various chemical characterization techniques for the analysis of trace elements in a subject sample because of its high precision.
Glow Discharge Mass Spectrometer: A brief Introduction.pptxReshma Kuppili
Glow Discharge Mass Spectrometer has gained popularity among various chemical characterization techniques for the analysis of trace elements in a subject sample because of its high precision.
X-Ray photoelectron spectroscopy, XPS was used to investigate the chemistry at the surface of the samples. The basic mechanism behind an XPS instrument is that the photons of a specific energy are used to excite the electronic states of atoms at and just below the surface of the sample.
There are several areas suited to measurement by XPS:
1. Elemental composition
2. Empirical formula determination
3. Chemical state
4. Electronic state
5. Binding energy
6. Layer thickness in the upper portion of surfaces
XPS has many advantages, such as it is is good for identifying all but two elements, identifying the chemical state on surfaces, and is good with quantitative analysis. XPS is capable of detecting the difference in chemical state between samples. XPS is also able to differentiate between oxidations states of molecules.
XPS has also some limitations, for instance, samples for XPS must be compatible with the ultra high vacuum environment. XPS is limited to measurements of elements having atomic numbers of 3 or greater, making it unable to detect hydrogen or helium. XPS spectra also take a long time to obtain. The use of a monochromator can also reduce the time per experiment.
Basics of Electrochemical Impedance SpectroscopyGamryInstruments
An introduction to Electrochemical Impedance Spectroscopy (EIS) theory and has been kept as free from mathematics and electrical theory as possible. If you still find the material presented here difficult to understand, don't stop reading. You will get useful information from this application note, even if you don't follow all of the discussions.
Laser-matter interaction depends on laser parameters as well as materials physical and chemical properties. The material response to the laser light depends on laser conditions and material properties. The material will respond differently to different intensities of laser light.
Electrical and Magnetic Properties of MaterialsAbeni9
Properties of a material which determine its response to an electric field.
Materials are classified based on their electrical properties as conductors, semiconductors and insulators and newly super conductors.
X-Ray photoelectron spectroscopy, XPS was used to investigate the chemistry at the surface of the samples. The basic mechanism behind an XPS instrument is that the photons of a specific energy are used to excite the electronic states of atoms at and just below the surface of the sample.
There are several areas suited to measurement by XPS:
1. Elemental composition
2. Empirical formula determination
3. Chemical state
4. Electronic state
5. Binding energy
6. Layer thickness in the upper portion of surfaces
XPS has many advantages, such as it is is good for identifying all but two elements, identifying the chemical state on surfaces, and is good with quantitative analysis. XPS is capable of detecting the difference in chemical state between samples. XPS is also able to differentiate between oxidations states of molecules.
XPS has also some limitations, for instance, samples for XPS must be compatible with the ultra high vacuum environment. XPS is limited to measurements of elements having atomic numbers of 3 or greater, making it unable to detect hydrogen or helium. XPS spectra also take a long time to obtain. The use of a monochromator can also reduce the time per experiment.
Basics of Electrochemical Impedance SpectroscopyGamryInstruments
An introduction to Electrochemical Impedance Spectroscopy (EIS) theory and has been kept as free from mathematics and electrical theory as possible. If you still find the material presented here difficult to understand, don't stop reading. You will get useful information from this application note, even if you don't follow all of the discussions.
Laser-matter interaction depends on laser parameters as well as materials physical and chemical properties. The material response to the laser light depends on laser conditions and material properties. The material will respond differently to different intensities of laser light.
Electrical and Magnetic Properties of MaterialsAbeni9
Properties of a material which determine its response to an electric field.
Materials are classified based on their electrical properties as conductors, semiconductors and insulators and newly super conductors.
Physics Sample Paper with General Instruction for Class - 12Learning Three Sixty
Learning 360 brings “Physics sample paper” for CLASS – 12. This document also carries 31 questions with solution of each given question for better understanding of the students. Download for free now; http://www.learning360.net/study_hub/1090-2/
Chiral Transverse Electromagnetic Waves with E H i to study Circular Dichroisminventionjournals
It is shown that a general class of transverse electromagnetic waves with E H i can be obtained. These waves possess magnetic helicity and chirality. This condition is important to excitation of nano molecules when it is necessary consider a global factor as the product of the parameter of optical chirality with the inherent enantiometric properties of the material. The absorption of a chiral molecule in a chiral electromagnetic field is proportional to the imaginary part of mixed electric-magnetic dipole polarizability of the molecules, which determines the circular dichroism, CD of molecules. Chiral fields with different handedness can be used to obtain basic information from the interaction fields-molecules with high optical chirality, having chiral hot spots in nodes of stationary waves with parallel components of electric and magnetic fields.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
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.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
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.
3. INTRODUCTION:
Louis de Broglie suggested in 1924 that particles could
have wave properties in addition to their familiar particle
properties. He hypothesized that the wavelength of the particle is
inversely proportional to its momentum:
λ :Wavelength
h : Planck's constant
p: momentum
Fig. 1: Wave-Particle duality
(1)
4. His conjecture was confirmed by the experiments of
Clinton Davisson and Lester Germer on the diffraction of
electrons at crystalline Nickel structures in 1927.
Fig.2: Davisson-Germer Experiment
5. In the present experiment the wave character of
electrons is demonstrated by their diffraction at a
polycrystalline graphite lattice (Debye-Scherrer diffraction).
In contrast to the experiment of Davisson and Germer where
electron diffraction is observed in reflection this setup uses a
transmission diffraction type similar to the one used by G.P.
Thomson in 1928.
6. THEORY:
In this experiment the electrons emitted by the hot cathode a
small beam singled out through a pin diagram. After passing
through a focusing electron-optical system the electrons are incident
as sharply limited monochromatic beam on a polycrystalline
graphite foil. The atoms of the graphite can be regarded as a space
lattice which acts as a diffracting grating for the electrons. On the
fluorescent screen appears a diffraction pattern of two concentric
rings which are centered around the indiffracted electron beam (Fig.
3). The diameter of the concentric rings changes with the
wavelength λ and thus with the accelerating voltage U as can be
seen by the following considerations:
7. D1
D2
Fig. 3: Schematic representation of the observed ring pattern due to the diffraction of
electrons on graphite. Two rings with diameters D1 and D2 are observed corresponding
to the lattice plane spacing d1 and d2.
8. From energy equation for the electrons accelerated by the
voltage:
U : accelerating voltage
e : electron charge
m : mass of the particle
v : velocity of the particle
The momentum p can be derived as:
(2)
(3)
9. Substituting equation (3) in equation (1) gives for the
wavelength:
(4)
According to Bragg’s law:
(5)
d : lattice plane spacing
θ : diffraction angle or glancing angle
11. In this experiment a polycrystalline material is used as
diffraction object. This corresponds to a large number of small
single crystallites which are irregularly arranged in space. As a
result there are always some crystals where the Bragg condition is
satisfied for a given direction of incidence and wavelength. The
reflections produced by these crystallites lie on a cones whose
common axis is given by the direction of incidence. Concentric
circles thus appear on a screen located perpendicularly to this axis.
The lattice planes which are important for the electron diffraction
pattern obtained with this setup possess the lattice plane spacing's.
12. Fig. 5: Lattice plane
spacing in graphite.
Fig. 6: Diffraction cone whose common axis is the
direction of incidence.
13. d1 = 2.13×10-10 m
d2 = 1.23×10-10 m
Using the equation
(6)
If we approximate tan2θ = sin2θ = 2sinθ for small angles we obtain
(7)
The substitution of equation (7) in (5) leads in first order diffraction
(n=1) to
14. D : ring diameter
L : distance between graphite and screen
d : lattice plane spacing
(8)
Due to equation (4) the wavelength A is determined by the
accelerating voltage U. Combining the equation (4) and equation
(7) shows that the diameters D1 and D2 of the concentric rings
change with the accelerating voltage U:
15. (9)
With
(10)
Measuring diameters D1 and D2 as function of the
accelerating voltage U allows thus to determine the lattice plane
spacing's d1 and d2.
16. Fig. 7: Schematic sketch for determining the diffraction angle.
L = 13.5 cm (distance between graphite foil and screen)
D: diameter of a diffraction ring observed on the screen
θ: diffraction angle
17. WORKING:
Fig. 8: Experimental setup (wiring diagram)
for observing the electron diffraction on
graphite. Pin connection
F1, F2: sockets for cathode heating
C: cathode cap
X: focusing electrode
A: anode
18. The experimental setup (wiring diagram) is shown in Fig. 8.
• Connect the cathode heating sockets F1 and F2 of the
tube stand to the output on the back of the high-voltage
power supply 10 kV.
• Connect the sockets C (cathode cap) and X (focusing
electrode) of the tube stand to the negative pole.
• Connect the socket A (anode) to the positive pole of the 5
KV/2 mA output of the high-voltage power supply 10 kV.
• Ground the positive pole on the high-voltage power
supply 10 kV.
19. • Apply an accelerating voltage U ≤ 5 kV and observe the
diffraction pattern.
• Vary the accelerating voltage U between 3 kV and 5 kV
in step of 0.5 kV and measure the diameter D1 and D2 of the
diffraction rings on the screen.
• Measure the distance between the graphite foil and the
screen.
20. OBSERVATIONS:
Table 1: Measured diameters D1 and D2 (average of 5
measurements) of the concentric diffraction rings as function
of the accelerating voltage U.
U(kV) D1(cm) D2(cm)
3.0 3.30 5.25
3.5 2.83 4.88
4.0 2.66 4.58
4.5 2.40 4.35
5.0 2.33 4.12
Distance between graphite foil and screen: L = 13.5 cm
21. EVALUATION AND RESULT:
Verification of the De Broglie equation:
The De Broglie relation equation (1) can be verified using
e = 1.6021×10-19 C
m = 9.1091 × 10-31 kg
h = 6.6256 × 10-34 J.s
in equation (4). The results for the wavelength determined by
equation (4) are λ1,theory and λ2,theory.. They are listed for the
diameters D1 and D2 in table 2 and table 3 below respectively.
22. Table 2: Measured diameter D1 , of the concentric diffraction
rings as function of the accelerating voltage U. The wavelengths
λ1 and λ1,theory are determined by equation (8) and equation (4)
respectively.
U(kV) D1(cm) λ1 (pm) λ1,theory (pm)
3.0 3.30 22.9 22.4
3.5 2.83 21.1 20.7
4.0 2.66 19.4 19.4
4.5 2.40 18.5 18.3
5.0 2.33 17.6 17.3
23. Table 3: Measured diameter D2 , of the concentric diffraction
rings as function of the accelerating voltage U. The wavelengths
λ2 and λ2,theory are determined by equation (8) and equation (4)
respectively.
U(kV) D2 (cm) λ2(pm) λ2,theory (pm)
3.0 5.25 22.6 22.4
3.5 4.88 21.0 20.7
4.0 4.58 19.7 19.4
4.5 4.35 18.6 18.3
5.0 4.12 17.5 17.3
24. The results λ1 and λ2 determined from the
diffraction pattern agree quite well with the theoretical
values λ1,theory and λ2,theory .Hence we can say that electrons
exhibit wave-particle duality according to De Broglie’s
postulates.
25. PRECAUTIONS:
• Do not operate the electron diffraction tube with high
voltages over 5 keV.
• Use the high-voltage power supply 10 kV for supplying the
electron diffraction tube with power.
• Do not expose the electron diffraction tube to mechanical
stress, and connect it only if it is mounted in the tube stand.
• Treat the contact pins in the pin base with care, do not bend
them, and be careful when inserting them in the tube stand.
• Keep to the operating parameters given in the section on
technical data.