64 research outputs found
Nanokompozyty elektrodowe Li-ion z samoorganizującymi się przewodzącymi warstwami węglowym
Basing on the developed and patented technology the nanocomposite cathodes were successfully prepared in a simple and inexpensive process of wet impregnation of polymer carbon precursor followed by controlled pyrolysis. Conductive carbon layers (CCLs) derived from hydrophilic polymers in solvent-free water mediated process, significantly enhances electrical conductivity of the material and improves its thermal properties, moreover the unique pore structure of CCLs assures easy lithium ions diffusion. Proposed solution allows to explore the potential of active material and improves overall performance of Li-ion batteries.Na podstawie opracowanej i opatentowanej technologii otrzymano nanokompozyty elektrodowe Li-ion. Nieskomplikowany i niedrogi proces wytwarzania przewodzących warstw węglowych (CCL) polegał na depozycji w środowisku wodnym prekursora węglowego na powierzchni ziaren materiału aktywnego, a następnie na kontrolowanej jego pirolizie. Otrzymane powłoki węglowe z hydrofilowych polimerów w istotnym stopniu polepszają właściwości elektryczne i termiczne kompozytów elektrodowych, a jednocześnie zapewniają kanały transportu (dyfuzji) jonów litu przez powłokę węglową. Zaproponowane rozwiązanie umożliwia pełne wykorzystanie korzystnych właściwości materiału aktywnego i poprawia ogólne parametry pracy ogniw litowo-jonowych
3D PET image reconstruction based on Maximum Likelihood Estimation Method (MLEM) algorithm
Positron emission tomographs (PET) do not measure an image directly. Instead,
they measure at the boundary of the field-of-view (FOV) of PET tomograph a
sinogram that consists of measurements of the sums of all the counts along the
lines connecting two detectors. As there is a multitude of detectors build-in
typical PET tomograph structure, there are many possible detector pairs that
pertain to the measurement. The problem is how to turn this measurement into an
image (this is called imaging). Decisive improvement in PET image quality was
reached with the introduction of iterative reconstruction techniques. This
stage was reached already twenty years ago (with the advent of new powerful
computing processors). However, three dimensional (3D) imaging remains still a
challenge. The purpose of the image reconstruction algorithm is to process this
imperfect count data for a large number (many millions) of lines-of-responce
(LOR) and millions of detected photons to produce an image showing the
distribution of the labeled molecules in space.Comment: 10 pages, 7 figure
TOF-PET detector concept based on organic scintillators
In this contribution we present a new concept of the large acceptance detector systems based on organic scintillators which may allow for simultaneous diagnostic of large fraction of the human body. Novelty of the concept lies in employing large blocks of polymer scintillators instead of crystals as detectors of annihilation quanta, and in using predominantly the timing of signals instead of their amplitudes
Multiple scattering and accidental coincidences in the J-PET detector simulated using GATE package
Novel Positron Emission Tomography system, based on plastic scintillators, is developed by the J-PET collaboration. In order to optimize geometrical configuration of built device, advanced computer simulations are performed. Detailed study is presented of background given by accidental coincidences and multiple scattering of gamma quanta
Plastic scintillators for positron emission tomography obtained by the bulk polymerization method
This paper describes three methods regarding the production of plastic
scintillators. One method appears to be suitable for the manufacturing of
plastic scintillator, revealing properties which fulfill the requirements of
novel positron emission tomography scanners based on plastic scintillators. The
key parameters of the manufacturing process are determined and discussed.Comment: 7 pages, 4 figure
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