introduction to thin film,techniques to deposit thin film, pulse laser deposition, creation and dynamics of plasma, types of thin films, nucleation and growth of film,
The Chernobyl nuclear accident in 1986 released significant radiation, with over 70% falling on Belarus. This forced the evacuation of over 130,000 Belarusians and contaminated 20% of the country's land. The radiation has led to increased cancer, birth defects, and suicides among the affected population. Children in particular have faced higher risks, such as a 100-fold increase in thyroid cancer in some areas of Belarus. The long-term health and environmental impacts on Belarus continue over 25 years later.
This document discusses the Shockley-Queisser limit, which describes the maximum theoretical efficiency of around 33.7% for a single p-n junction solar cell. It outlines approaches that can exceed this limit, including multi-junction solar cells that use multiple semiconductor materials to capture more energy from sunlight, concentrating sunlight to increase efficiency, using multiple exciton generation in quantum dots to produce multiple electron-hole pairs from one photon, and up-conversion or down-conversion of photons to better match the solar spectrum to the materials' bandgaps.
Materials Modelling: From theory to solar cells (Lecture 1)cdtpv
This document provides an overview of a mini-module on materials modelling for solar energy applications. It introduces the lecturers and outlines the course structure, which includes lectures on modelling, interfaces, and multi-scale approaches. It also describes a literature review activity where students will present a research paper using materials modelling in photovoltaics. Recommended textbooks are provided on topics like bonding in solids, computational chemistry, and density functional theory for solids.
The document discusses the use of single layer molybdenum disulfide (MoS2) nanopores for desalination. It begins with an introduction to MoS2, describing its lamellar structure and weak van der Waals forces between layers. It then discusses using MoS2 nanopores for more efficient and energy-saving desalination compared to traditional reverse osmosis. The document concludes that single layer MoS2 nanopores show promise as an effective membrane for seawater desalination due to their thin, ultrastructure and lower energy requirements.
introduction to thin film,techniques to deposit thin film, pulse laser deposition, creation and dynamics of plasma, types of thin films, nucleation and growth of film,
The Chernobyl nuclear accident in 1986 released significant radiation, with over 70% falling on Belarus. This forced the evacuation of over 130,000 Belarusians and contaminated 20% of the country's land. The radiation has led to increased cancer, birth defects, and suicides among the affected population. Children in particular have faced higher risks, such as a 100-fold increase in thyroid cancer in some areas of Belarus. The long-term health and environmental impacts on Belarus continue over 25 years later.
This document discusses the Shockley-Queisser limit, which describes the maximum theoretical efficiency of around 33.7% for a single p-n junction solar cell. It outlines approaches that can exceed this limit, including multi-junction solar cells that use multiple semiconductor materials to capture more energy from sunlight, concentrating sunlight to increase efficiency, using multiple exciton generation in quantum dots to produce multiple electron-hole pairs from one photon, and up-conversion or down-conversion of photons to better match the solar spectrum to the materials' bandgaps.
Materials Modelling: From theory to solar cells (Lecture 1)cdtpv
This document provides an overview of a mini-module on materials modelling for solar energy applications. It introduces the lecturers and outlines the course structure, which includes lectures on modelling, interfaces, and multi-scale approaches. It also describes a literature review activity where students will present a research paper using materials modelling in photovoltaics. Recommended textbooks are provided on topics like bonding in solids, computational chemistry, and density functional theory for solids.
The document discusses the use of single layer molybdenum disulfide (MoS2) nanopores for desalination. It begins with an introduction to MoS2, describing its lamellar structure and weak van der Waals forces between layers. It then discusses using MoS2 nanopores for more efficient and energy-saving desalination compared to traditional reverse osmosis. The document concludes that single layer MoS2 nanopores show promise as an effective membrane for seawater desalination due to their thin, ultrastructure and lower energy requirements.
Graphene materials for opto and electronic applications 2014 Report by Yole D...Yole Developpement
What is the industrial potential behind the graphene academic R&D hype?
$141M GRAPHENE MATERIALS MARKET IN 2024 WILL BE DRIVEN MAINLY BY TRANSPARENT CONDUCTIVE ELECTRODES AND ENERGY STORAGE APPLICATIONS
Graphene is a two-dimensional (2D) material with exceptional properties, such as ultrahigh electrical and thermal conductivities, wide-range optical transmittance and excellent mechanical strength and flexibility. These properties make it a promising material for emerging and existing applications in printed & flexible circuitry, ultrafast transistors, touch screens, advanced batteries and supercapacitors, ultrafast lasers, photodetectors and many other non-electronic applications.
Although graphene technology is still in its infancy, remarkable progress has been made in the last few years developing graphene production methods. Numerous opto and electronic devices based on graphene have been demonstrated on lab-scale models. However, the numerous challenges of graphene technology should not be underestimated. The lack of bandgap in graphene is its key fundamental challenge. Other technology challenges are related to the development of industrial methods to produce graphene with high and consistent quality at acceptable costs.
Although today there is no graphene-based electronic application in mass production, several companies already offer commercially graphene materials. The graphene material market value in 2013 was about $11 million, represented principally by the demand for the R&D and prototyping. Two scenarios for the future market growth are presented in the report. According to the base scenario, the global annual market value for graphene materials in opto and electronic applications will reach $141 million in 2024, featuring a 2013-2019 CAGR of 18.5%. Accelerated market growth is expected after 2019, with a 2019-2024 CAGR of 35.7%. In 2024, the graphene material market will be represented mainly by the demand for transparent conductive electrodes and advanced batteries and supercapacitors.
HOW CAN GRAPHENE TECHNOLOGY CHALLENGES AND APPLICATION POTENTIAL BE TRANSFORMED INTO BUSINESS OPPORTUNITIES?
In order to reach the best possible performance on lab-scale devices, high quality materials are required. Material suppliers able to consistently deliver high-quality materials have a competitive advantage on the graphene market.
The booming interest in graphene technologies has led to a high demand on graphene equipment. As shown in the report, CVD equipment makers today mainly focus on the R&D equipment used to produce high-quality graphene.
More information on that report at http://www.i-micronews.com/reports/Graphene-materials-opto-electronic-applications/3/416/
Doping introduces impurities into a semiconductor crystal to modify its conductivity. N-type doping uses elements with 5 valence electrons like phosphorus, which provides an extra electron that is loosely bound and can move freely. P-type doping uses elements with 3 valence electrons like boron, which accepts an electron from the semiconductor, leaving behind a positively charged hole. Both doping types increase the number of charge carriers, with n-type providing free electrons and p-type providing free holes. This allows control over whether the semiconductor behaves as an electron or hole conductor.
The document summarizes research into synthesizing lithium lanthanum manganese oxide (LiLa x Mn 2 − x O 4) cathode materials for lithium-ion batteries through a sol-gel method. It was found that doping lithium manganese oxide (LiMn2O4) with lanthanum improved structural and electrochemical properties. Specifically, LiLa0.05Mn1.95O4 exhibited single phase structure, enhanced cycling stability, and rate capability compared to undoped LiMn2O4 based on X-ray diffraction, Raman spectroscopy, galvanostatic cycling, and cyclic voltammetry results discussed in the document.
Methods of synthesis and all types of core-shell nanoparticles with ceramic core and metal shell.
روشهای سنتز و انواع نانو ذرات هسته پوسته با هسته سرامیکی و پوسته فلزی
The document discusses lithium-ion batteries. It begins by defining batteries and describing their basic components. It then distinguishes between primary and secondary batteries. Lithium batteries are described as either using lithium metal or lithium compounds as the anode. Lithium-ion batteries, a type of secondary battery, are described in more detail, including their principle of operation through lithium ion intercalation, their construction with four layers, and their charging/discharging working involving lithium ion insertion into electrode lattices. Advantages include high energy density and improved safety, while applications include cameras, medical devices, and consumer electronics.
1. The document introduces a course on the principle and application of photocatalysis.
2. Photocatalysis uses solar energy to promote chemical reactions for energy conversion and environmental purification without changing the photocatalyst.
3. Semiconductor materials like TiO2 can be used as photocatalysts by generating electron-hole pairs when irradiated by light which then trigger redox reactions to degrade pollutants.
Electron beam lithography (often abbreviated as e-beam lithography or EBL) is the process of transferring a pattern onto the surface of a substrate by first scanning a thin layer of organic film (called resist) on the surface by a tightly focused and precisely controlled electron beam (exposure) and then selectively removing the exposed or nonexposed regions of the resist in a solvent (developing). The process allows patterning of very small features, often with the dimensions of submicrometer down to a few nanometers, either covering the selected areas of the surface by the resist or exposing otherwise resist-covered areas. The exposed areas could be further processed for etching or thin-film deposition while the covered parts are protected during these processes. The advantage of e-beam lithography stems from the shorter wavelength of accelerated electrons compared to the wavelength of ultraviolet (UV) light used in photolithography.
In EBL, a resist layer is directly patterned by scanning with an electron beam electronically. Modern EBL systems have very good depth of focus (several hundred nanometres) and are able to correct for large-scale height variations of the wafer (of several hundred microns), and so are able to cope well with the rough surface topology of typical GaN wafers and associated wafer bow. EBL also has the advantage of allowing multiple designs to be fabricated together on one wafer. EBL is, however, a slow and expensive process, which is not practical for production. Substrate charging and proximity error effects must be taken into account to get good quality devices. Charging effects can be overcome by application of a sub-nanoscale removable conductive layer on top of the resist. Proximity error correction effects are overcome using specialised design correction software.
The document discusses the evolution and advanced designs of VVER reactors. It describes the current challenges facing nuclear power plants and how generation 3+ designs, such as the VVER-1200, aim to address these through extended lifetimes, reduced costs and construction times. Future innovative designs discussed include the VVER-600, VVER-SCP generation 4 supercritical water cooled reactor, and concepts using tight fuel assemblies for a closed nuclear fuel cycle. The VVER-1200 design for project AES-2006 forms the basis for the further developed MIR-1200 design being implemented in the Czech Republic.
Laser Processing of Different materials and its application.aman1312
Presentation of laser application in different types of industry for material processing. Laser materials processing is done on various materials such as metals, non metals, ceramics, polymer materials.
Perovskite solar cells are a promising photovoltaic technology that has seen rapid increases in efficiency from 3.8% in 2009 to 19.3% in 2014. Perovskites have a unique crystal structure and can be prepared through various methods like spin coating and inkjet printing. They offer benefits such as high absorption, tunable bandgaps, and flexibility. However, challenges remain around stability issues from oxygen, moisture, UV light and heat that can be addressed through material engineering and encapsulation. With further research into replacing lead and improving stability, perovskite solar cells have the potential to become a leading solar technology of the future.
2021 recent trends on high capacity cathodekzfung2
The document summarizes recent work on nickel-rich layered oxide cathodes and cobalt-free layered oxide cathodes for lithium-ion batteries.
For nickel-rich NMC811 cathodes, a multi-step synthesis method produced better crystallinity and less cation mixing compared to a one-pot method, as indicated by a higher I003/I104 ratio from XRD. The multi-step NMC811 also showed better capacity retention over 30 cycles.
For cobalt-free NMF111 cathodes, a multi-step method reduced the formation of unwanted LMO213 phases during synthesis compared to a one-pot method. NPD and XRPD analysis confirmed the layered structure of
This document discusses potential non-carbon anode materials for lithium ion batteries. It describes three categories of materials: 1) insertion materials like titanium oxides that store lithium through intercalation, 2) alloying materials like tin oxide that react with lithium in an alloying/dealloying mechanism, and 3) conversion materials like metal oxides and phosphides that undergo a conversion reaction with lithium. While these alternative anode materials offer higher capacities than graphite, the document notes that challenges remain like capacity fading and potential hysteresis that have prevented their widespread commercial use.
This document discusses novel materials for batteries. It begins by introducing solid state batteries and the requirements for electrode materials, including low working potential, high specific capacity, good interface with electrolytes, and high electrode kinetics. It then discusses various materials that could be used as electrodes, including lithium carbon electrodes using graphite and graphite intercalation compounds. Different types of graphite like natural, synthetic, and HOPG are described. The document also discusses intercalation of lithium ions into carbon and potential carbon-sodium electrodes. Finally, it discusses various material classes like rutile, perovskite, and spinel materials that could be used as cathodes in rechargeable lithium ion batteries. Specific
This presentation discusses used fuel reprocessing, including its history and current techniques. It provides an overview of key steps in the aqueous reprocessing approach, including head-end processing, primary separations (such as the PUREX process), and supporting operations like off-gas treatment. The presentation examines historical reprocessing techniques and facilities, current commercial reprocessing facilities abroad, and the advantages and disadvantages of different approaches.
The document discusses computational modeling of perovskites for photovoltaic applications. Perovskites have shown great promise for solar cells due to their excellent optoelectronic properties. Computational modeling can provide insights into perovskite properties that are difficult to obtain experimentally. While lead-based perovskites have achieved high efficiencies, their toxicity is a concern, creating interest in developing non-toxic alternatives through computational studies and materials design. Opportunities and challenges of computational modeling for understanding perovskites and designing new materials are also examined.
Chernobyl disaster and what are the lessons we have to learn especially India which having 21 Nuclear Centers or Plants
Reference Video Link is given below
https://www.youtube.com/watch?v=R9JSGU8MRb0
An introduction of perovskite solar cellsalfachemistry
This article introduces the development, structure and work mechanism of perovskite solar cells. Visit https://www.alfa-chemistry.com/products/perovskite-solar-cells-139.htm for more information.
Graphene materials for opto and electronic applications 2014 Report by Yole D...Yole Developpement
What is the industrial potential behind the graphene academic R&D hype?
$141M GRAPHENE MATERIALS MARKET IN 2024 WILL BE DRIVEN MAINLY BY TRANSPARENT CONDUCTIVE ELECTRODES AND ENERGY STORAGE APPLICATIONS
Graphene is a two-dimensional (2D) material with exceptional properties, such as ultrahigh electrical and thermal conductivities, wide-range optical transmittance and excellent mechanical strength and flexibility. These properties make it a promising material for emerging and existing applications in printed & flexible circuitry, ultrafast transistors, touch screens, advanced batteries and supercapacitors, ultrafast lasers, photodetectors and many other non-electronic applications.
Although graphene technology is still in its infancy, remarkable progress has been made in the last few years developing graphene production methods. Numerous opto and electronic devices based on graphene have been demonstrated on lab-scale models. However, the numerous challenges of graphene technology should not be underestimated. The lack of bandgap in graphene is its key fundamental challenge. Other technology challenges are related to the development of industrial methods to produce graphene with high and consistent quality at acceptable costs.
Although today there is no graphene-based electronic application in mass production, several companies already offer commercially graphene materials. The graphene material market value in 2013 was about $11 million, represented principally by the demand for the R&D and prototyping. Two scenarios for the future market growth are presented in the report. According to the base scenario, the global annual market value for graphene materials in opto and electronic applications will reach $141 million in 2024, featuring a 2013-2019 CAGR of 18.5%. Accelerated market growth is expected after 2019, with a 2019-2024 CAGR of 35.7%. In 2024, the graphene material market will be represented mainly by the demand for transparent conductive electrodes and advanced batteries and supercapacitors.
HOW CAN GRAPHENE TECHNOLOGY CHALLENGES AND APPLICATION POTENTIAL BE TRANSFORMED INTO BUSINESS OPPORTUNITIES?
In order to reach the best possible performance on lab-scale devices, high quality materials are required. Material suppliers able to consistently deliver high-quality materials have a competitive advantage on the graphene market.
The booming interest in graphene technologies has led to a high demand on graphene equipment. As shown in the report, CVD equipment makers today mainly focus on the R&D equipment used to produce high-quality graphene.
More information on that report at http://www.i-micronews.com/reports/Graphene-materials-opto-electronic-applications/3/416/
Doping introduces impurities into a semiconductor crystal to modify its conductivity. N-type doping uses elements with 5 valence electrons like phosphorus, which provides an extra electron that is loosely bound and can move freely. P-type doping uses elements with 3 valence electrons like boron, which accepts an electron from the semiconductor, leaving behind a positively charged hole. Both doping types increase the number of charge carriers, with n-type providing free electrons and p-type providing free holes. This allows control over whether the semiconductor behaves as an electron or hole conductor.
The document summarizes research into synthesizing lithium lanthanum manganese oxide (LiLa x Mn 2 − x O 4) cathode materials for lithium-ion batteries through a sol-gel method. It was found that doping lithium manganese oxide (LiMn2O4) with lanthanum improved structural and electrochemical properties. Specifically, LiLa0.05Mn1.95O4 exhibited single phase structure, enhanced cycling stability, and rate capability compared to undoped LiMn2O4 based on X-ray diffraction, Raman spectroscopy, galvanostatic cycling, and cyclic voltammetry results discussed in the document.
Methods of synthesis and all types of core-shell nanoparticles with ceramic core and metal shell.
روشهای سنتز و انواع نانو ذرات هسته پوسته با هسته سرامیکی و پوسته فلزی
The document discusses lithium-ion batteries. It begins by defining batteries and describing their basic components. It then distinguishes between primary and secondary batteries. Lithium batteries are described as either using lithium metal or lithium compounds as the anode. Lithium-ion batteries, a type of secondary battery, are described in more detail, including their principle of operation through lithium ion intercalation, their construction with four layers, and their charging/discharging working involving lithium ion insertion into electrode lattices. Advantages include high energy density and improved safety, while applications include cameras, medical devices, and consumer electronics.
1. The document introduces a course on the principle and application of photocatalysis.
2. Photocatalysis uses solar energy to promote chemical reactions for energy conversion and environmental purification without changing the photocatalyst.
3. Semiconductor materials like TiO2 can be used as photocatalysts by generating electron-hole pairs when irradiated by light which then trigger redox reactions to degrade pollutants.
Electron beam lithography (often abbreviated as e-beam lithography or EBL) is the process of transferring a pattern onto the surface of a substrate by first scanning a thin layer of organic film (called resist) on the surface by a tightly focused and precisely controlled electron beam (exposure) and then selectively removing the exposed or nonexposed regions of the resist in a solvent (developing). The process allows patterning of very small features, often with the dimensions of submicrometer down to a few nanometers, either covering the selected areas of the surface by the resist or exposing otherwise resist-covered areas. The exposed areas could be further processed for etching or thin-film deposition while the covered parts are protected during these processes. The advantage of e-beam lithography stems from the shorter wavelength of accelerated electrons compared to the wavelength of ultraviolet (UV) light used in photolithography.
In EBL, a resist layer is directly patterned by scanning with an electron beam electronically. Modern EBL systems have very good depth of focus (several hundred nanometres) and are able to correct for large-scale height variations of the wafer (of several hundred microns), and so are able to cope well with the rough surface topology of typical GaN wafers and associated wafer bow. EBL also has the advantage of allowing multiple designs to be fabricated together on one wafer. EBL is, however, a slow and expensive process, which is not practical for production. Substrate charging and proximity error effects must be taken into account to get good quality devices. Charging effects can be overcome by application of a sub-nanoscale removable conductive layer on top of the resist. Proximity error correction effects are overcome using specialised design correction software.
The document discusses the evolution and advanced designs of VVER reactors. It describes the current challenges facing nuclear power plants and how generation 3+ designs, such as the VVER-1200, aim to address these through extended lifetimes, reduced costs and construction times. Future innovative designs discussed include the VVER-600, VVER-SCP generation 4 supercritical water cooled reactor, and concepts using tight fuel assemblies for a closed nuclear fuel cycle. The VVER-1200 design for project AES-2006 forms the basis for the further developed MIR-1200 design being implemented in the Czech Republic.
Laser Processing of Different materials and its application.aman1312
Presentation of laser application in different types of industry for material processing. Laser materials processing is done on various materials such as metals, non metals, ceramics, polymer materials.
Perovskite solar cells are a promising photovoltaic technology that has seen rapid increases in efficiency from 3.8% in 2009 to 19.3% in 2014. Perovskites have a unique crystal structure and can be prepared through various methods like spin coating and inkjet printing. They offer benefits such as high absorption, tunable bandgaps, and flexibility. However, challenges remain around stability issues from oxygen, moisture, UV light and heat that can be addressed through material engineering and encapsulation. With further research into replacing lead and improving stability, perovskite solar cells have the potential to become a leading solar technology of the future.
2021 recent trends on high capacity cathodekzfung2
The document summarizes recent work on nickel-rich layered oxide cathodes and cobalt-free layered oxide cathodes for lithium-ion batteries.
For nickel-rich NMC811 cathodes, a multi-step synthesis method produced better crystallinity and less cation mixing compared to a one-pot method, as indicated by a higher I003/I104 ratio from XRD. The multi-step NMC811 also showed better capacity retention over 30 cycles.
For cobalt-free NMF111 cathodes, a multi-step method reduced the formation of unwanted LMO213 phases during synthesis compared to a one-pot method. NPD and XRPD analysis confirmed the layered structure of
This document discusses potential non-carbon anode materials for lithium ion batteries. It describes three categories of materials: 1) insertion materials like titanium oxides that store lithium through intercalation, 2) alloying materials like tin oxide that react with lithium in an alloying/dealloying mechanism, and 3) conversion materials like metal oxides and phosphides that undergo a conversion reaction with lithium. While these alternative anode materials offer higher capacities than graphite, the document notes that challenges remain like capacity fading and potential hysteresis that have prevented their widespread commercial use.
This document discusses novel materials for batteries. It begins by introducing solid state batteries and the requirements for electrode materials, including low working potential, high specific capacity, good interface with electrolytes, and high electrode kinetics. It then discusses various materials that could be used as electrodes, including lithium carbon electrodes using graphite and graphite intercalation compounds. Different types of graphite like natural, synthetic, and HOPG are described. The document also discusses intercalation of lithium ions into carbon and potential carbon-sodium electrodes. Finally, it discusses various material classes like rutile, perovskite, and spinel materials that could be used as cathodes in rechargeable lithium ion batteries. Specific
This presentation discusses used fuel reprocessing, including its history and current techniques. It provides an overview of key steps in the aqueous reprocessing approach, including head-end processing, primary separations (such as the PUREX process), and supporting operations like off-gas treatment. The presentation examines historical reprocessing techniques and facilities, current commercial reprocessing facilities abroad, and the advantages and disadvantages of different approaches.
The document discusses computational modeling of perovskites for photovoltaic applications. Perovskites have shown great promise for solar cells due to their excellent optoelectronic properties. Computational modeling can provide insights into perovskite properties that are difficult to obtain experimentally. While lead-based perovskites have achieved high efficiencies, their toxicity is a concern, creating interest in developing non-toxic alternatives through computational studies and materials design. Opportunities and challenges of computational modeling for understanding perovskites and designing new materials are also examined.
Chernobyl disaster and what are the lessons we have to learn especially India which having 21 Nuclear Centers or Plants
Reference Video Link is given below
https://www.youtube.com/watch?v=R9JSGU8MRb0
An introduction of perovskite solar cellsalfachemistry
This article introduces the development, structure and work mechanism of perovskite solar cells. Visit https://www.alfa-chemistry.com/products/perovskite-solar-cells-139.htm for more information.
Week 5. Basics and clinical uses of MR spectroscopy.Dr. Jakab András
The document provides information about an upcoming course, including:
1. Upcoming lecture topics and dates, including MR Spectroscopy on October 30th.
2. Details about an upcoming final test on basic imaging techniques and spectroscopy.
3. Where to find study materials for the test, including lecture materials in PDF format.
This document provides information about an upcoming "Multimodal Imaging in Neurosciences" course, including:
1) Dates and topics for upcoming lectures, as well as details about a final test on basic imaging techniques.
2) An overview of various neuroimaging modalities like CT, MRI, PET, and their applications.
3) A brief history of the development of high-intensity focused ultrasound (HIFU) technology from the 1880s to present.
Week 3. Neurosurgical planning with multimodal imagingDr. Jakab András
The document discusses the use of multimodal imaging in neurosurgery. It describes how multimodal imaging can provide maximum information beyond just anatomical structures, including blood supply, function, and spatial visualization to help with surgical planning and navigation. It outlines some of the key indications for neurosurgery like tumors, arteriovenous malformations, epilepsy, and discusses how clinicians can utilize different imaging modalities like MRI, DTI, fMRI, and PET to obtain information on anatomy, vessels, eloquent tracts, function and laterality, tumor characterization and metabolism, and localization for stereotactic planning.
Week 2. Diffusion magnetic resonance imaging, tractography, mapping the brain...Dr. Jakab András
The document summarizes key points about multimodal neuroimaging techniques, with a focus on diffusion magnetic resonance imaging (MRI) and fiber tracking. It discusses how diffusion MRI can be used to measure and visualize water diffusion in the brain, which provides information about tissue microstructure and white matter pathways. Specifically, it describes diffusion tensor imaging (DTI) and how it is used to quantify diffusion anisotropy and direction. The clinical and research applications of DTI and fiber tractography are also summarized, such as characterizing white matter integrity and disorders, assessing brain tumors, and mapping brain connectivity and development.
Week 1. Basics of multimodal imaging and image processing. Functional magneti...Dr. Jakab András
This document discusses multimodal neuroimaging. It provides an introduction to combining multiple imaging modalities such as CT, MRI, PET, and EEG to gain complementary information. Key benefits of multimodal imaging include anatomical alignment of images and fusion of structural and functional data. Examples of hybrid imaging devices that facilitate multimodal approaches are PET-CT and PET-MRI scanners. The document also gives an overview of functional MRI techniques for mapping brain activity and networks involved in sensory, motor, cognitive and resting state functions.
A review of recent evidences for macroscopic reorganisation from in vivo imaging studies. This presentation focuses on the neuroplastic changes of white matter and the possible mechanisms behind this.
Charting the human thalamus - basic contepts and recent developmentsDr. Jakab András
This document summarizes a study on developing a probabilistic tractography and segmentation method to chart the human thalamus. The study used diffusion tensor imaging and probabilistic tractography to visualize cortico-thalamic connections. It then developed a statistical shape model of the mean thalamus atlas incorporating these connectivity maps. The method was able to align the atlas to individual subjects' geometry with sub-millimeter accuracy, outperforming conventional alignment methods. This individualized target mapping method could help guide image-guided neurosurgery of the thalamus.
Connectivity-augmented Surgical Targeting: Individualization of a 3D Atlas of...Dr. Jakab András
This study developed a tool to generate individualized target maps of the thalamus for image-guided neurosurgery. Researchers aligned a 3D probabilistic atlas of the thalamus to patient MRI scans using statistical shape models, refined by diffusion tensor tractography data on corticothalamic connections. Comparison to conventional alignment methods showed the new technique provided superior matching accuracy of less than 1mm. Evaluation using post-mortem high-resolution MRI confirmed the spatial accuracy for identifying intrathalamic landmarks. The individualized thalamic maps incorporating structural and connectivity data have potential for direct image-guided targeting in neurosurgical procedures.
1. Víz: az elfelejtett molekula
Diffúziós jelenségeken alapuló
képalkotás (DWI, DTI)
Dr. Jakab András
Dr. Berényi Ervin
Multimodális képalkotás az idegtudományban
kreditkurzus 2010 (c)
2. „Az elfelejtett molekula”
Különleges tulajdonságok:
•H-kötések
•Más poláris molekulákhoz
„kötődnek” (fehérjék?)
•Felületi feszültség
•Magas hőkapacitás
•Az oxigén oldhatósága a vízben
3. „Az elfelejtett molekula”
A víz a biológiai szövetekben
Kémiai Nobel –díj 2003: Peter
Agre (aquaporins), Roderick
MacKinnon (K-csat.)
4.
5. Víz: mérések és képalkotás?
T1 relaxációs idő
T2 relaxációs idő
Protondenzitás
Diffúziógátlás,
diffúziós
együttható
Diffúzió iránya
Diffúzió
anizotrópiája
Diffúziós
térképezés
Más atommagok
„Konvencionális
MRI”
Diffusion-
weighted
imaging
Diffusion tensor
imaging
Diffusion spectral
imaging, HARDI
MR spectroscopy
6. Diffúzió: fizikai alapok
1827, Robert Brown
Először: „vis vitalis”,
később szervetlen
részecskékre is kimutatta
Véletlenszerű mozgás
„Hőmozgás” F.M.Exner, 1900
7. A diffúzió: fizikai alapok
1905: „a csodálatos év”
“On a Heuristic Point of View on the Creation
and Conversion of Light”(17 March
1905)(Photo-Electric Effect) Nobel prize in
physics, 1921
“On the Electrodynamics of Moving Bodies” (30
June 1905)
“Does the inertia of a body depend on its
energy content?”(27 September 1905)(Theory of
Special Relativity) E = mc²
“Investigation on the Theory of the Brownian
Movement: On the motion of small particles
suspended in liquids at rest …”(11 May 1905)
Albert Einstein, 1905 körül
8. Einstein, 1905
A hőmérséklet molekuláris-kinetikai
elmélete: Brown mozgás <- ->
molekuláris diffúzió
RANDOM WALK
0
?
10. Diffúzió súlyozott képalkotás
(DWI)
Le Bihan & Breton, CRASS, 1985
Intravoxel incoherent motion
Képalkotás közben molekuláris
elmozdulás = az MRI jel
befolyásolása
Térben változó mágneses tér
alkalmazása a „spin echo” MRI
képalkotás során: a hely kódolása
Egy helyben álló vs. Mozgó
részecskék
13. Diffúzió súlyozott képalkotás képi
kontrasztja
Ha a vizsgálat közben elmozdulnak a
részecskék: kisebb jel keletkezik
Ha lassú a diffúzió, magasabb jel
(„több marad a vizsgált területen”)
14. DWI képalkotás: amit tudni
illik Diffúzió súlyozás nagysága (b-faktor)
◦ Defókuszáló, refókuszáló gradiens nagysága (erősség,
alak)
◦ Időtartama, szimmetria, időbeli eltérés
◦ Diffúzió kódoló grádiens térbeli iránya! (-> DTI!)
◦ Mit tudunk meg a DWI képekről?
15. DWI alkalmazása
Diffúziógátlás: sejtpusztulás, membránintegritás,
energiaellátottság
Korábban, mint a „strukturális” eltérés (T1 v. T2-n)
Diffúzió és perfúzió alkalmazása: stroke imaging,
penumbra meghatározása (ischaemiás stroke:
elzárt agyi ér)
DWI: működnek a sejtek???Perfúzió: kapnak vért a
16. Miért különleges a szöveti
diffúzió? A tér különböző irányába eltérő nagyságot
mutat = anizotróp
Forrás: Karla Miller, FMRIB, University of Oxford
17. Milyen diffúzió létezik?
Szabad diffúzió (izotróp)
Gátolt diffúzió („restricted”)
Akadályozott diffúzió („hindered")
18. Diffúziós irány megjelenítése
A biológiai diffúzió anizotróp, a tér egyes irányába eltérő diffúziós
együtthatót mutat.
A diffúzió-súlyozó mágneses tér „irányában” legnagyobb a nagysága
Herpes encephalitis
forrás:
emedicine.medscape.com
Egészséges agy
ACA stroke
forrás: RADsounds Wiki
19. Diffúziós tenzor (?)
képalkotás Sokféle irányú diffúzió súlyozó grádiens = „sok irányból
megvizsgáljuk a diffúzió nagyságát”
Peter Basser (NIH)
TENZOR:
a megjelenítés
kulcsa
20. A „diffúziós térképezés”
diffúzió súlyozott felvételek
készítése
voxelen belüli diffúzió térbeli
karakterisztikája
tenzor illesztés a diffúzió
jellemzésére
A tenzoriális információ ábrázolása
szürkeskálás v. egyéb skaláris képeken
21. Mi szükséges a diffúziós tenzor
képalkotáshoz?
-Több irányú diffúzió súlyozó
grádiens alkalmazása a
képalkotás (SS EPI) során
- legalább 6 irány
- ajánlott: 24-32 irányból
- a kapott sokdimenziós
adathalmaz számítógépes
feldolgozása, színkódolt és
egyéb számolt képek
- együttes megjelenítés más
képalkotó módszerekkel
22. Mit tudunk mérni a DTI-vel?
DIFFÚZIÓ NAGYSÁGA (hasonlóan a DWI-hez): ADC
Diffúzió rendezettsége, anizotrópia mértéke (FA)
Diffúzió iránya (Color encoded map)
Diffúzió nagysága az axonlefutással egy irányban (parallel
diffusivity)
Diffúzió nagysága az axonlefutásra merőlegesen (perpendicular
diffusivity)
23. Fehérállomány: mit tudunk mérni a DTI-
vel?
Anizotrópia ++ Anizotrópia +
Anizotrópia -
Diffúzió -
Anizotrópia - -
Diffúzió ? / n
Anizotrópia - -
Diffúzió - -
24. Diffúziós traktográfia
Tract = pálya
Diffúziós tenzor adatok alapján a fehérállományi pályák
háromdimenziós megjelenítése
Agyi összeköttetések (?)
Számítógépes adatfeldolgozás és megjelenítés
32. A diffúziós tenzorokon túl…
A diffúzió irányának pontosabb feloldása = HARDI (high angular
resolution diffusion imaging)
Diffúzió súlyozó grádiensek akár 50-200 irányból is
A rostlefutás pontosabb ábrázolása: crossing fibers esetén
ODF, Q-ball, Diffusion spectral imaging, etc.
33.
34.
35. DTI és a multimodalitás
DTI és más, pl. strukturális MRI képek együttes megjelenítése
Térbeli illesztés, koregisztráció szükséges
TÖBBLETINFORMÁCIÓ: fehérállományi képletek
36. ÖSSZEFOGLALÁS A MÓDSZEREKRŐL
T1, T2-súlyozott MRI: a hidrogén protonok
relaxációs ideje a szöveti környezettől függően
Diffúzió súlyozott MRI (DWI) : a diffúzió
nagysága, irányultság nélkül
Diffúziós tenzor MRI (DTI): a diffúziós iránya,
anizotrópiája
Traktográfia: pályák lefutása
Diffusion spectrum imaging (DSI): diffúzió térbeli
karakterisztikája, egy térrészen belüli többszörös
rostpopulációk megjelenítése
A DTI és egyéb módszerek adatait kombinálni
lehet más képalkotó módszerekkel (T1 MRI, CT,
PET, stb.)
42. DTI a neuroonkológiában
A. Jakab, M. Emri, P. Molnár, E. Berényi.
Glioma grade assessment by using
histogram analysis of diffusion tensor
imaging-derived maps. Neuroradiology.
2010 Sep 21.
Az agytumor grádusa:
Alacsony? (WHO I-II)
Magas? (WHO III-IV)
43. DTI: klinikai példák
• Forrás: Nucifora et al. (2007) Diffusion-Tensor MR Imaging and Tractography:
Exploring Brain Microstructure and Connectivity. Radiology. 245, 367-384.
44. • Forrás: Nucifora et al. (2007) Diffusion-Tensor MR Imaging and Tractography:
Exploring Brain Microstructure and Connectivity. Radiology. 245, 367-384.
45.
46. • Forrás: Nucifora et al. (2007) Diffusion-Tensor MR Imaging and Tractography:
Exploring Brain Microstructure and Connectivity. Radiology. 245, 367-384.
47. • Forrás: Nucifora et al. (2007) Diffusion-Tensor MR Imaging and Tractography:
Exploring Brain Microstructure and Connectivity. Radiology. 245, 367-384.
48. • Forrás: Lee et al. Diffusion-Tensor MR Imaging and Fiber Tractography: A New
Method of Describing Aberrant Fiber Connections in Developmental CNS Anomalies
Cerebral palsy in a 20-month-old girl with
spastic hemiplegia.