I gave 1 hour seminar at ANSTO (Australian Nuclear Science and Technology Organization) to introduce my approach to magnetism. I see myself as an experimental physicist who is studying magnetism by using neutron scattering techniques. Throughout my career, I had learned local structure analysis (PDF), magnetic structural analysis, and inelastic neutron scattering technique to investigate superconductor, multiferroics, antiferromagnets, helimagnets, and frustrated magnets. I was trying to explain my approach to magnetism as an experiment physicist to both professional scientists and novices.
Los días 22 y 23 de junio de 2016 organizamos en la Fundación Ramón Areces un simposio internacional sobre 'Materiales bidimensionales: explorando los límites de la física y la ingeniería'. En colaboración con el Massachusetts Institute of Technology (MIT), científicos de este prestigioso centro de investigación mostraron las propiedades únicas de materiales como el grafeno, de solo un átomo de espesor, y al mismo tiempo más resistente que el acero y mucho más ligero.
Dr. Toma Susi (University of Vienna, Austria) invited talk at the MRS Spring Meeting 2018 in Phoenix, AZ titled "Towards atomically precise manipulation of 2D nanostructures in the
electron microscope".
Los días 22 y 23 de junio de 2016 organizamos en la Fundación Ramón Areces un simposio internacional sobre 'Materiales bidimensionales: explorando los límites de la física y la ingeniería'. En colaboración con el Massachusetts Institute of Technology (MIT), científicos de este prestigioso centro de investigación mostraron las propiedades únicas de materiales como el grafeno, de solo un átomo de espesor, y al mismo tiempo más resistente que el acero y mucho más ligero.
Overview of unique capabilities of the ADF modeling suite to model properties of organic electronics (charge transport, phosphorescence, light absorbance). Highlighted with examples from the recent literature.
I gave 1 hour seminar at ANSTO (Australian Nuclear Science and Technology Organization) to introduce my approach to magnetism. I see myself as an experimental physicist who is studying magnetism by using neutron scattering techniques. Throughout my career, I had learned local structure analysis (PDF), magnetic structural analysis, and inelastic neutron scattering technique to investigate superconductor, multiferroics, antiferromagnets, helimagnets, and frustrated magnets. I was trying to explain my approach to magnetism as an experiment physicist to both professional scientists and novices.
Los días 22 y 23 de junio de 2016 organizamos en la Fundación Ramón Areces un simposio internacional sobre 'Materiales bidimensionales: explorando los límites de la física y la ingeniería'. En colaboración con el Massachusetts Institute of Technology (MIT), científicos de este prestigioso centro de investigación mostraron las propiedades únicas de materiales como el grafeno, de solo un átomo de espesor, y al mismo tiempo más resistente que el acero y mucho más ligero.
Dr. Toma Susi (University of Vienna, Austria) invited talk at the MRS Spring Meeting 2018 in Phoenix, AZ titled "Towards atomically precise manipulation of 2D nanostructures in the
electron microscope".
Los días 22 y 23 de junio de 2016 organizamos en la Fundación Ramón Areces un simposio internacional sobre 'Materiales bidimensionales: explorando los límites de la física y la ingeniería'. En colaboración con el Massachusetts Institute of Technology (MIT), científicos de este prestigioso centro de investigación mostraron las propiedades únicas de materiales como el grafeno, de solo un átomo de espesor, y al mismo tiempo más resistente que el acero y mucho más ligero.
Overview of unique capabilities of the ADF modeling suite to model properties of organic electronics (charge transport, phosphorescence, light absorbance). Highlighted with examples from the recent literature.
2018-11-26 Investigation of the band structure of quantum wells based on gapl...LeonidBovkun
The present PhD thesis primarily aims at filling some of existing gaps in our understanding of the electronic band structure in 2D and quasi-2D heterostructures based on HgTe/HgCdTe and InAs/InSb materials, which both may be tuned into topologically insulating phase using particular structural parameter. To explore their properties, the primal experimental technique, infrared and THz magneto-spectroscopy operating in a broad of magnetic fields, is combined with complementary magneto-transport measurements. This combination of experimental methods allows us to get valuable insights into electronic states not only at the Fermi energy, but also in relatively broad vicinity.
The public trial lecture presented by Mohammadreza Nematollahi on 8th of October 2014 at Norwegian University of Science and Technology. The theoretical models and the experimental progress of highly mismatched alloys, as well as their optoelectronic applications are covered.
These are the slides from the webinar hosted by NNIN @ University of Michigan on May 28, 2013. Find out more about my views on how atomic-scale modeling can help the development of nanoelectronics based on nanowires, interfaces, graphene. The special Atomistix ToolKit
(PhD Dissertation Defense) Theoretical and Numerical Investigations on Crysta...James D.B. Wang, PhD
(I'm no longer in this academic field, and thus sharing my PhD dissertation slide here to anyone who would be interested in it)
=================================================
In order to prevent the spurious wave reflections and to improve the computational efficiency in nanomechanical simulation, this dissertation performs a series of theoretical/numerical studies on the crystalline nano material, including nanomechanics of monatomic lattice, isothermally non-reflecting boundary condition, fast updating of neighbor list, and the application/simulation in laser-assisted nano-imprinting.
2018-11-26 Investigation of the band structure of quantum wells based on gapl...LeonidBovkun
The present PhD thesis primarily aims at filling some of existing gaps in our understanding of the electronic band structure in 2D and quasi-2D heterostructures based on HgTe/HgCdTe and InAs/InSb materials, which both may be tuned into topologically insulating phase using particular structural parameter. To explore their properties, the primal experimental technique, infrared and THz magneto-spectroscopy operating in a broad of magnetic fields, is combined with complementary magneto-transport measurements. This combination of experimental methods allows us to get valuable insights into electronic states not only at the Fermi energy, but also in relatively broad vicinity.
The public trial lecture presented by Mohammadreza Nematollahi on 8th of October 2014 at Norwegian University of Science and Technology. The theoretical models and the experimental progress of highly mismatched alloys, as well as their optoelectronic applications are covered.
These are the slides from the webinar hosted by NNIN @ University of Michigan on May 28, 2013. Find out more about my views on how atomic-scale modeling can help the development of nanoelectronics based on nanowires, interfaces, graphene. The special Atomistix ToolKit
(PhD Dissertation Defense) Theoretical and Numerical Investigations on Crysta...James D.B. Wang, PhD
(I'm no longer in this academic field, and thus sharing my PhD dissertation slide here to anyone who would be interested in it)
=================================================
In order to prevent the spurious wave reflections and to improve the computational efficiency in nanomechanical simulation, this dissertation performs a series of theoretical/numerical studies on the crystalline nano material, including nanomechanics of monatomic lattice, isothermally non-reflecting boundary condition, fast updating of neighbor list, and the application/simulation in laser-assisted nano-imprinting.
Official announcement of the next edition of the event.BMRS Meeting
Presentation of the XXI B-MRS Meeting (Maceió, AL, Oct 1st to 5th, 2023) by the chair Prof. Carlos Jacinto da Silva (UFAL) at the closing session of the XX B-MRS Meeting.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
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.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
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.
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.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
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.
FINE CHARACTERIZATION OF NANOSCALE MATERIALS BY TEM METHODS
1. FINE CHARACTERIZATION OF
NANOSCALE MATERIALS
BY TEM METHODS
Daniel M. Ugarte
Dept. Física Aplicada, Instituto de Física Gleb Wataghin-IFGW
Univ. Estadual de Campinas- UNICAMP, Campinas SP BRAZIL
2. Outline:
Introduction : Science progress: Ideas vs Tools
& new TEM paradigm (instrumentation)
TEM studies of Nanosystems:
Semiconductor NWs: defects & lattice distortion
Precession Electron Diffr. (PED): Screw disloc. +Torsion (Eshelby Twist)
Nanoparticles Characterization: beyond imaging
Pair Distrib. Function (PDF+PED)
Challenging aspects: an Unsolved Equation
Complex instrumentation & Human Resources Formation
Summary & …
Epilogue & aknowledgments
3. LEGO, danês ”leg godt”
“Play well!!!"
by Richard Feymann (December 29th 1959)
There's Plenty of Room at the Bottom
…arrange the atoms the way we want;
…greater range of possible properties
…possible by laws of physics. …
see individual atoms distinctly?
… importance of improving the electron microscope
not against the laws of diffraction of the electron.
The Nobel Prize
in Physics 1965
SCIENCE,
VOL 338, 14 DEC 2012
Achieving Great Scientific Progress
Thomas Kuhn (1922-1996) 100 Years
The Structure of Scientific Revolutions (1962)
“paradigm” (system of ideas “) discontinuous shift from one paradigm to other
Image and Logic (1997) Peter Galison
A different view of history…dominated by tools (nuclear physics, astronomy,...
XX century greatest scient. discovery: DNA (X-ray diffraction)
normal science ???? in Kuhn Picture
4. 2008 KAVLI PRIZE
in Nanoscience
Geometrical parameters
(Radius, Helicity)
conductors, insulator, semiconductor
no doping needed
Future ...Electronics (bottom-up)...
Nature 354, 56 (07 November 1991)
NW
Axis
Sumio Iijima
Discovery of Carbon nanotubes
Helicity!!!!! e-Diffraction:
Atomic resolution imaging
HRTEM seeing atoms (counting layers)
Semiconductor Metallic
EF
EF
5. Lagos et al, PRL 106, 055501 (2011)
Tamb ~ 300 K
Maureen Lagos
2012 CAPES Prize
PhD Physics
(Present:
Prof. MacMaster U.)
In-situ: Mechanical Elongation of atomic-szie Au wires (T dependence)
T ~ 150 K
Uncorrected TEM
+ Liq . N2 holder
6. TEM Paradigm Shifter: Aberration Correction
TEM is based on
magnetic lenses
Cylindrically Symm.
Magn. Lenses
are alway convergent
𝐶 → 𝜃
Strong Spherical aberration
Lorentz force
Multipolar Magnetic Lenses
S
S
N
N
N
S
F
B
v
Breaking
rotational symmetry
(limitation for ~ 50 ys)
Sub-ångström resolution
imaging and chemical analysis
using electron beams."
The Kavli Prize
in Nanoscience
2020
M. Haider, H. Rose, K. Urban, O. L. Krivanek
Kavli Prize Week Sept. 3-9 2022; Oslo & Trondheim, Norway.
7. Thomas, et al, CPL 631 (2015) 103
The rapidly changing face of TEM electron microscopy
Tomography
1D
Spectrum
3D
Data set
4D
Data set
Real Space
Shape, Atomic posit.
Spectroscopic
3D reconstruction
Reciprocal Space
3D reconstruction
Big Data
Machine learning
New Detectors
Quantitative Anal;
Spectr, Diffr & images
In-situ: T, Gazes,
liquids, etc.
Radiation Damage (Low dose)
Proteins << 1 e/Å2
STEM, maps 106 -109 e/Å2
Ptychography
(phase)
Electron Diffraction mapping (multiple Scattering)
Dynamical 𝒉𝒌𝒍 𝒉𝒌𝒍
𝟐
Wide
beam
STEM
Narrow beam
(4D STEM)
8. translating unknown structures or processes into
quantifiable, physically meaningful descriptors
and model representations.
Qualitative
Quantitative comparisons
(Residue)
Refinement
Model/ Simulations
Machine learning
9. TEM Characterization of NP:
Imaging most popular
LNNano, Campinas
Murilo Moreira
AuAg
Atomic Resolution
Electron
diffraction
Critical issues
Beam damage
Low Statistic
(few nanoparticles)
103 e-/Å2
104-106 e-/Å2
Low Dose approaches for
Structural Characterization
Alternatives to Imaging ??
Wide beam
Projection
Narrow beam
Scanning
HAADF
PRL 124, 106105(2020)
100 nm
6 e-/A2
beam ~5 nm
Macpherson et al, Nature 294, 607 (2022)
Pt
perovskite
(extremely beam sensitive)
Cs0.05FA0.78MA0.17Pb(I0.83Br0.17)3
FA formamidinium
MA methylammonium
Direct Detection Camera
512x512 (medipix)
11. Electron diff Pattern under “quase” Kinematical conditions
Precession Electron Diffraction- PED
Midgley & Eggeman IUCrJ 2 (2015) 126
Vincent & Midgley,
Ultramic.
53 (1994) 271.
Precession
de-Scan
Static Diff pattern
Hollow cone
Convent. Precess.
e-
Beam
y
z
x
Crystal orientation
(hkil)
along e-beam Direction
In Sample coord.
ND
PED
+nm Probe
+Fast Adq.
(SPED)
+ Pattern. Matching
(Kinem. patterns)
Post-Processing
Rauch, E. F. et al.. Microsc. Anal. 22, S5–S8 (2008).
ACOM
(Autom. Crystal orient. map)
Maps of Crystal
orientation and phases
12. Outline:
Introduction : generating novel ideas/concepts (NANO )
& new TEM paradigm (instrumentation)
TEM studies of Nanosystems:
Semiconductor NWs: defects & lattice distortion
Precession Electron Diffr.: Screw dislocation +Torsion (Eshelby Twist)
Nanoparticles Characterization: beyond imaging
Pair Distrib. Function (PDF+PED)
Challenging aspects: an Unsolved Equation
Complex instrumentation & Human Resources Formation
Summary & …
Epilogue & aknowledgments
13. Long and Short NWs
(~2 µm & > 4 µm )
[0-110] [2-1-10]
CBED
(1 nm probe)
InP NWs (Wurzite)
(0.14 ± 0.01 ) °/nm
30°Rot
Screw
dislocation
Frank
Model Growth
III-V Semiconductor Nanowires
CBE Reactor (Chem. Beam Epitaxy)- UNICAMP
Prof. Monica Cotta
Tizei et al.,
PRL 107, 195503 (2011)
P
In
BF-STEM:
periodical contrast bands
Crystal Torsion
Luiz Tizei
Present:
CNRS-Orsay FR
VLS-Au Catalyst.
14. Eshelby twist (50s- Classical Elasticity Theory)
Eshelby JD, J. App. Phys. 24, 176 (1953)
First observation 2008:
Branched NWs PbSe and PbS
Bierman MJ et al,
Science 320, 1060 (2008)
Screw
Dislocation
(Torque)
+
Free surface
(whisker or NW)
Double Helix Tower
Stockholm
Turning Torso, Malmö
Finite cylinder with
Axial Screw Dislocation)
𝟐
Torsion
B Burgers vector
R radius
15. ND= Crystal Normal
(hki 0)
e-beam
1) Torsion (Eshelby Twist)
2) Screw Dislocation
z
x
y
L
𝑁
𝑁
[0001] Crystal
Helicoidal Planes
Eshelby Twist (axial screw Dislocation)
InP NW (Wurtzite)
e-
Beam
y
z
x
PED yields
Crystal orientation
(hkil)
along
e-beam Direction
In Sample coord.)
ND
Disoreintation vs.
Reference Wire axis
P
In
High Spatial Resolution PED
(HSR-PED) or 4D STEM
Torsion
Screw
Dislocation
CM300-F 200 kV, ASTAR
prec. Angle 0.5 deg.,
Patterns 144x144 pixels
Dept. Mat. Sci. Metal.
Univ. Cambridge UK
16. 0001 -2110
-1010
Torsion rate |A|
(0.070±0.002) °/nm
3D NW shape
(hki0)
3D determination of wire shape
VADF
f
3D
2D
300 nm
0
L
y
z
x
𝟐
Wire do not need to be perfectly oriented
(InP beam sensitive)
Ugarte et al, Nano Research 12, 939 (2019)
(hkil)
17. SPED 10 ms/pixel
Rotation 100 hz
PED pattern 144 X 144 pixels
~20000 pix
Highly distorted
Precession
de-Scan
Static pattern
100-1000 frames/s
Got linear response
Intensity-
Quantitative
ED Crystallography
1) Monocrystal
2) Pair Distrib.Function
PDF (+PED)
PED
Brazda et al, Science 364, 667 (2019)
Optical
recording
Phosporous
screen
e-Powder
Diffr.
Hoque et al,
J. Phys. Chem C 123.19894 (2019)
Correa et al,
ACS Applied Nanomat 4, 12541 (2021)
1) ACOM
(Autom. Crystal orient. map)
Post- processing 4D-STEM
Ihkl
-based
In-column camera
(CCD,CMOS, DDC)
2) Ring
Pattern
18. Prof. Dr. Arturo Ponce
Dept. Phys. Astron.
UTexas (Santo Antônio).
Jeol 2010F
TVIPS F416 detector CMOS
(16 bits, 4096x4096 bits).
Quantitative Comparison
Intensities Ihkil
(Experim. vs. Model)
Intensity
2)
V-ADF
20 nm
1) Template Matching
Diff. Pattern
Library
Cross-
correlation
Best fit
Kinematical
pattern
Refinement
3 Optimized Parameters
Torsion angle
C-axis Orientation
Scaling Intensity Factor
( ~80-100 s/pattern)
Correa et al, unpublished
ACOM (Autom. Crystal orient. map)
2-beam modeling
Dynam. Diffr. Approx.
Rauch et al, Symmetry 13, 1675 (2021)
Atomic scatt. factor Z
No Bragg angle dependence
Gjonnes, Ultram. 69,1 (1997) Oleynikov et al, Ultram. 107, 523 (2007)
19. Applied Ln to
Experim
Intensities
+
Cross Correl.
Template Matching
py4DSTEM (freeware)
Ophus et al, Microsc Microanal. 28. 390 (2022), .
Pyxem (freeware, Hyperspy)
McLaren et al, Microsc,&Microana, 26, 1110 (2020).
Cautaerts et al, Ultramicr.237, 113517 (2022)
Rauch et al,
Symmetry
13, 1675 (2021)
Expected: 0.017 ± 0.002 °/𝑛𝑚
Refinment ~60-80 s/pixel
R ~20 %
As expected using 2-beam model
Palatinus et al, Acta Cryst. B 71, 740 (2016)
Template Matching Refinement Ihkl
𝑅 =
∑ 𝐼 − 𝐼 𝐼
∑ 𝐼
𝒃
𝒄
𝒅
𝒂
y
z
x
X0.1
X0.15
Twist Rate Values
(0.006 ± 0.001) °/nm
20. Outline:
Introduction : generating novel ideas/concepts (NANO )
& new TEM paradigm (instrumentation)
TEM studies of Nanosystems:
Semiconductor NWs: defects & lattice distortion
Precession Electron Diffr.: Screw dislocation +Torsion (Eshelby Twist)
Nanoparticles Characterization: beyond imaging
Pair Distrib. Function (PDF+PED)
Challenging aspects: an Unsolved Equation
Complex instrumentation & Human Resources Formation
Summary & …
Epilogue & aknowledgments
21. Gaz
Coil AuAg
Cluster source
Cylindrical sputtering
1 3 5 [nm]
Counts
Mass-selected Cluster (Prof. Varlei)
Varlei Murilo (Ph.D)
Mach. Learning,
EDS-STEM
Leonardo (Ph.D.)
PED, ePDF
Diffraction
de Sá A. et al, J. Vac. Sci. Technol. B, 32, 061804 (2014)
Quantitative EDS on NP
(Big data, Mach. Learn.,, etc.)
( Inv Talk: V. Rodrigues,
Symp. L, X Micromat, Wedn. 28/09 , 14.30 )
Statistical validity of derived conclusion?
Low Dose approaches vs Imaging
(1-10 e/Å2 vs 106 e/Å2 )
Pair Distribution Function based on PED
Complex Polycyrst. Structure???
AuAg alloy NP
Titan Themis
22. i) e-Diffraction-based PDF
Abeykoon et al. (Billingue group), Z. Kristallogr. 227, 248 (2012)
SUePDF Software, Tran et al, J. Appl. Cryst. 50, 304 (2017)
Need of additional methods for quantitative and rapid
structural characterization of nanomaterials
Billingue & Levin, The Problem with determining atomic Structure at the Nanoscale, Science, 316, 561 (2007)
Pair Distribution Function (PDF)
Alternative for Crystallography in NANO
(peak broadening, etc.)
Billinge SJL. The nanostructure problem. Physics 3, 25 (2010)
Billinge SJL. The rise of the X-ray PDF method.
Phil. Trans. R. Soc. A 377: 20180413 (2019 )
Quantitative information may be
extracted from PDFs
using modeling.
JATOBÁ beamline high-energy, high-photon flux beam
focused on m size full X-ray scattering technique
+ PED
( 𝒉𝒌𝒍 𝒉𝒌𝒍
𝟐
)
Tutorial on
Powder X-ray Diffr.
for Characterizing
Nanoscale Materials
ACS Nano 13, 7359
(2019)
CdS spher. NP
23. Pair Distribution Function
- Suited for materials without long-range order
(Amorphous, Nanoparticles)
- Sensitive to NP domain structure
- Describes the distances between pairs of atoms
Start:
Powder Diffraction
(Reciprocal Space)
Reduced PDF
(Real Space)
Fourier T
to
Real Space
ePDFAllows
Mean Information
Minimal Sample Mass
(<ng)
Low Dose ( < 10 e-/Å2)
Quantitative
Crystallography
(Model vs Measurement)
2
Underneath the Bragg Peaks:
T. Egami and S.J.L. Billinge (2003)
Pair Distribution Function (PDF)
Mid-range
Short Range
24. SAED = 39% PED = 22%
Implementation of ePDF + PED
cryo-TEM holder (Gatan 915)
JEOL 2010F at 200 kV.
ASTAR Nanomegas
16-megapixel F416
CMOS camera (TVIPS)
U-Texas San Antonio
(Prof. A. Ponce)
Using Simple
Kinematical Modeling Software: SuePDF + DiffPy
Electron Diffraction:
Special Needs
25. Home-made Software (Python)
Aim: TEM specificity
- Astigmatism correction and pattern centering
- Azimuthal integration
- Background subtraction & normalization
- PDF calculation
- Powder diff. simulation: Debye Scattering Eq.
- Residue Calculation: Quantitative
6 nm
5 -10 nm
(Measured)
Astigm Corr.: F. Niekiel et al., Ultramic., 2017, 176, 161
DSE: B.D. Hall et al., Computer in Phys., 1991, 5, 414
Data Analysis
L. M. Correa
IFGW, Brazil.
Pair Distrib.Function (PDF) Based on PED
Composition : CAu ~70%
Mean Diameter : 6 nm
Mass : ≈ 2000 NPs or 4 fg
AuAg NP
PED 2.0º
- Not at all a fancy TEM
- TECNAI G2 200kV (LaB6),
(Univ. Fed. São Carlos)
- CCD Orius (Axial Cam!!!)
- RT , Dose = 10 e-/Å2
Cluster Source:
de Sá A. D. T., et
al.,
J. Vac. Sci. Technol.
B, 2014, 32, 061804
26. Data Processing (home-made)
1st Condition, Total Scatt. Conservation
2nd Condition, High Q
Equal
Background Substraction
Simultaneous Optimization
potential function (Q –n)
+
a-C Substrate (measured)
a-C
Simulation Powder Diff. Pattern (Debye Eq.)
Hall &, Monot, Computers in Physics 5, 414 (1991)
Non-periodic struct.
Disorder, etc.
( ) ( )
fcc
Dh Ico
27. Four different models
(a) fcc;
(b) single twinned fcc;
(c) Dh; decahedral,
bco-Body-Cent.-Orthorombic;
(d) Ih Icosahedral (rombohedral)
Why Dh is better?
A twin defect shows local order different from fcc or bco
Dh provides the correct balance
of local order and medium-range order
(different tetrhedra have
well established orientation relationship)
Optimization Results for SAED/PED
PED smaller residues
Quantitative comparison with
Kinematical diffraction modeling.
Only2 Parameters Optimization:
1) Debye-Waller 2) NP diameter
28. Complex Sample: Size distribution,
apparent agglomeration, polycrystalline??
Only 3 Parameters:
(1) Debye-Waller
Size Distribution ((2) mean and (3) width)
NP Structure
Decahedral
Considering Size Distribution
Structure Description (Residue):
Our Conventional TEM: 15%
Synchrotron: 12 to 17%
Correa et al., ACS Applied Nanomat. 2021, 4, 11, 12541
15%
20%
22%
23%
Longer r (bigger NP, stronger Dynamic. Effects)
29. Outline:
Introduction : generating novel ideas/concepts (NANO )
& new TEM paradigm (instrumentation)
TEM studies of Nanosystems:
Semiconductor NWs: defects & lattice distortion
Precession Electron Diffr.: Screw dislocation +Torsion (Eshelby Twist)
Nanoparticles Characterization: beyond imaging
Pair Distrib. Function (PDF+PED)
Challenging aspects: an Unsolved Equation
Complex instrumentation & Human Resources Formation
Summary & …
Epilogue & aknowledgments
30. “reproducibility crisis”, (U.S. National Academies of Science)
poor and incorrect materials data analysis in the literature.
analysis of XPS data in journals that emphasize next generation materials,
30% of the analyses are completely incorrect (Linford and Major, 2019).
proliferation of advanced analytical instruments seem to
have exceeded the world’s supply of expertise
to collect, interpret, and review the results obtained from them.
NOT “Black-box”
Push-botton Operators
need for reproducibility
For research results to have longevity and impact,
others must be able to replicate it, build on it
and take it in new directions
Nature, 608, 9 (4 August 2022)
Retraction Watch (Ivan Oransky)
evidence from surveys, studies and reports
~1 in 50 papers (~2%)
meet at least one criteria for retraction the
(Committee on Public. Ethics, non-profit collective in
Eastleigh, UK)
(actual rate 0.1%) 1/1000
31. A single method is rarely enough
electronic, magnetic, structural, thermal and many more …..
“Big” Facilities: Powerful “EXPENSIVE” machines
(ex. Synchrotron, state-of-the-art TEM, supercomputers,…)
“Small” science (universities)
individual-investigator laboratory
Dept, Ints., University
Materials characterization and the
evolution of material Sciences
CNPEM
Sirius
LMNANO
Tools OK
Higher impact....
?????
What about Ideas?
Human Resources
Formation
Starting research program,
questions, studying, testing,
routine work, Basic Infrastructure
Understanding
focusing ideas
Developing intuition
Consolidating
expertise/tech. ability
profound question!!
viable answer
time
Cutting-edge study
(ex. 10 hs TEM)
(Big Facility)
Bottom-up
1000
hs
.
TEM
32. Summary
- Electron nano-crystallography: PED (Tomography)
2022 new section of IUCrJ dedicated to e- crystallography
- Scanning Electron Diffraction (4D-STEM) strong growth
Strain nm-resolution (ACOM based on intesities Ihkl)
low dose 5-10 e/Å2 ,PED Patterns->Machine learning
- e-PDF+PED: Quantitative statistical information NP ensemble
sample (< pgr) Low dose (10 e/Å2) Low profile TEM!!!!
- Quantitative Chemical Composition inside few-nm NPs (EDS , ML)
Not presented ( Inv Talk: V. Rodrigues, Symp. L, X Micromat, Wedn. 14.30)
Funding (SPED NW):
Funding (ePDF): Advanced Microscopy Center at UTSA.
Dept.of Defense The Welch Foundation NSF
Brazil: CNPq, FAPESP, UNICAMP,CAPES
Epilogue & Aknowledgments: A few more slides
33. Start an Electron Microscopy Facility (90´s)
300kV
HRTEM
LV-SEM
FEG-SEM 200kV CTEM 200kV FEG-TEM
1999 2007-2009 Objectives (Since 1994)
1) To operate as an
“Actual” open
multi-user laboratory
(not Feudal, not sycophantic)
2) To train human resources
(Users/Students must operate the
microscope by themselves)
Best way to induce change
Education/ Teaching Young researchers
Still inside this endless battle!!
(Since 1994 .....
still many operational windmills.
“José Arana Varela” Award, XX B-MRS Meeting (SBPMat )
Annual SBPMat Award for Contribution to Braz. Materials Science
34. 2002 (J.A.Varela, E. Longo, E. Leite)
UNESP, UFSCar
FEG-TEM Expansion, Fapesp Sci. Dir.
1998 (Christian Colliex-
Lab. Phys. Sol., U. Paris Sud)
1994 (Prof. Cecilia Salvadori-USP)
Drive CPS-Caxambu MG-CPS
Quotation Sample Prep. Lab.
(Clatches periode)
Feb 2000 Nov 2000 Dec 1998, Daniela, Paulinho, Varlei
LNLS Directors: Cylon, Aldo, Ricardo Initial LME Team
35. 9th Nov 2020,
SBPMat Recognition
Placa gravada com os dizeres:
A Sociedade Brasileira de Pesquisa de Materiais (SBPMat)
homenageia a contribuição fundamental de Ricardo Rodrigues
para o êxito do desenvolvimento e implantação das
fontes brasileiras de luz síncrotron UVX e Sirius,
que colocaram o Brasil
na vanguarda mundial da pesquisa em materiais.