Impact of energetic particle orbits on long range frequency chirping of BGK modes

Long range frequency chirping of Bernstein-Greene-Kruskal modes, whose existence is determined by the fast particles, is investigated in cases where these particles do not move freely and their motion is bounded to restricted orbits. An equilibrium oscillating potential, which creates different orbit topologies of energetic particles, is included into the bump-on-tail instability problem of a plasma wave. With respect to fast particles dynamics, the extended model captures the range of particles motion (trapped/passing) with energy and thus represents a more realistic 1D picture of the long range sweeping events observed for weakly damped modes, e.g. global Alfven eigenmodes, in tokamaks. The Poisson equation is solved numerically along with bounce averaging the Vlasov equation in the adiabatic regime. We demonstrate that the shape and the saturation amplitude of the nonlinear mode structure depends not only on the amount of deviation from the initial eigenfrequency but also on the initial energy of the resonant electrons in the equilibrium potential. Similarly, the results reveal that the resonant electrons following different equilibrium orbits in the electrostatic potential lead to different rates of frequency evolution. As compared to the previous model [Breizman B.N. 2010 Nucl. Fusion 50 084014], it is shown that the frequency sweeps with lower rates. The additional physics included in the model enables a more complete 1D description of the range of phenomena observed in experiments.Comment: Submitted to Nuclear Fusion 25/01/201

Thermally stimulated relaxation and behaviors of oxygen vacancies in SrTiO<inf>3</inf> single crystals with (100), (110) and (111) orientations

Abstract The strontium titanate (SrTiO3) single crystals with different orientations of (100), (110) and (111) were investigated using thermally stimulated depolarization current (TSDC) measurements, which has been proved to be an effective strategy to fundamentally study the relationship between relaxation phenomena and defect chemistry in dielectrics. The origins of different relaxations in SrTiO3 crystals were identified and the activation energy of oxygen vacancies was estimated from TSDC measurements. It was further found that oxygen-treated SrTiO3 crystals exhibit different relaxation behaviors. Noticeable changes of thermal relaxation associated with oxygen vacancies have taken place in relation to the crystalline anisotropy. The SrTiO3 (110) samples display higher concentration and activation energy of oxygen vacancies. First-principles calculations were carried out on SrTiO3 (110) crystals to study the effect of oxygen vacancy on different surface microstructure. From the resulting minimum formation energy of 0.63 eV, it demonstrates that the oxygen vacancies tend to form on the TiO-terminated surfaces. Considering the band structure, oxygen vacancies near the surface contribute to the transition of crystal from insulator to metallic characteristic.</jats:p

Evaluation of Therapeutic Effects of Radiotherapy during Treatment of Lung Adenocarcinoma in Mice with Positron Emission Tomography Imaging of 18F-FLT and 18F-FDG

Purpose: To assess the role of 3'-deoxy-3'-18F-fluoro-thymidine (18F-FLT) and 2'-deoxy-2'-18F-fluorodeoxy- glucose (18F-FDG) positron emission tomography (PET) imaging in the evaluation of the therapeutic effects of radiotherapy during treatment of lung adenocarcinoma.Methods: Eighteen mice with lung adenocarcinoma were randomly divided into 2 groups; each group was randomly paired and evenly divided into three smaller groups, namely, A, B and C. Group A served as the control group without any treatment; mice in group B were received radiotherapy in sites of tumor. A single dose of 2000 cGy, 6MV x-ray was used in this experiment; mice in group C also received radiotherapy at sites of tumors two days before the experiment using the same procedure and dose as group B. Micro PET imaging was taken after intravenous injection of 18F-FLT and 18F-FDG through the mice’s tail.Results: The intake ratio of 18F-FLT and 18F-FDG was much higher at the tumor sites. After radiotherapy, 18F-FLT uptake was significantly lower than that of the control group (p &lt; 0.05), while there was no obvious change of 18F-FDG uptake. There was a significant decrease in T/NT value of FLT PET imaging group 24 and 48 h after radiotherapy; a significant difference could be seen, compared with that before radiotherapy (p &lt; 0.05).Conclusion: Change in 18F-FLT uptake induced by radiotherapy is more sensitive than that of 18F-FDG. Intake of 18F-FLT is lowered more significantly after radiotherapy than that of 18F-FDG, and this can serve as evidence that 18F-FLT is an effective tracer to monitor the therapeutic effect of radiotherapy on malignant tumors.Keywords: 3'-deoxy-3'-18F-fluoro-thymidine, 2'-deoxy-2'-18F-fluoro-deoxy-glucose, Radiotherapy, Positron Emission Tomography Imaging, Cell Proliferation, Lung Adenocarcinom

Bosonic Super Liouville System: Lax Pair and Solution

We study the bosonic super Liouville system which is a statistical transmutation of super Liouville system. Lax pair for the bosonic super Liouville system is constructed using prolongation method, ensuring the Lax integrability, and the solution to the equations of motion is also considered via Leznov-Saveliev analysis.Comment: LaTeX, no figures, 11 page

Optimal transport for a novel event description at hadron colliders

We propose a novel strategy for disentangling proton collisions at hadron colliders such as the LHC that considerably improves over the current state of the art. Employing a metric inspired by optimal transport problems as the cost function of a graph neural network, our algorithm is able to compare two particle collections with different noise levels and learns to flag particles originating from the main interaction amidst products from up to 200 simultaneous pileup collisions. We thereby sidestep the critical task of obtaining a ground truth by labeling particles and avoid arduous human annotation in favor of labels derived in situ through a self-supervised process. We demonstrate how our approach—which, unlike competing algorithms, is trivial to implement—improves the resolution in key objects used in precision measurements and searches alike and present large sensitivity gains in searching for exotic Higgs boson decays at the High-Luminosity LHC

Optimal Principal Component Analysis in Distributed and Streaming Models

We study the Principal Component Analysis (PCA) problem in the distributed and streaming models of computation. Given a matrix $A \in R^{m \times n},$ a rank parameter $k < rank(A)$, and an accuracy parameter $0 < \epsilon < 1$, we want to output an $m \times k$ orthonormal matrix $U$ for which $$|| A - U U^T A ||_F^2 \le \left(1 + \epsilon \right) \cdot || A - A_k||_F^2,$$ where $A_k \in R^{m \times n}$ is the best rank-$k$ approximation to $A$. This paper provides improved algorithms for distributed PCA and streaming PCA.Comment: STOC2016 full versio

Secure Particle Filtering With Paillier Encryption-Decryption Scheme: Application to Multi-machine Power Grids

This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI10.1109/TSG.2023.3271949, IEEE Transactions on Smart Grid.National Natural Science Foundation of China under Grants 61933007, U21A2019 and 62273088; Program of Shanghai Academic/Technology Research Leader of China under Grant 20XD1420100; Hainan Province Science and Technology Special Fund of China under Grant ZDYF2022SHFZ105; UK Research and Innovation Future Leaders Fellowship under Grants MR/W011360/1; Engineering and Physical Sciences Research Council (EPSRC) of the UK; Royal Society of the UK; Alexander von Humboldt Foundation of Germany