4,304 research outputs found
The Ultrasonic/Shear-Force Microscope: A Metrology Tool for Surface Science and Technology
This paper describes recent results obtained with the Ultrasonic/Shear-Force Microscope (SUNM), an analytical tool suitable for investigating the quite different dynamic displayed by fluid-like films when subjected to mesoscopic confinement and while in intimate contact with two sliding solid boundaries. The SUNM uses two sensory modules to concurrently but independently monitor the effects that fluid-mediated interactions exert on two sliding bodies: the microscope’s sharp probe (attached to a piezoelectric sensor) and the analyzed sample (attached to an ultrasonic transducer). This dual capability allows correlating the fluid-like film’s viscoelastic properties with changes in the probe’s resonance frequency and the generation of sound. A detailed monitoring of sliding friction by ultrasonic means and with nanometer resolution is unprecedented, which opens potential uses of the versatile microscope as a surface and subsurface material characterization tool. As a surface metrology tool, the SUNM presents a potential impact in diverse areas ranging from fundamental studies of nanotribology, confinement-driven solid to liquid phase transformation of polymer films, characterization of industrial lubricants, and the study of elastic properties of bio-membranes. As a sub-surface metrology tool, the SUNM can be used in the investigation of the elastic properties of low- and high-k dielectric materials, piezoelectric and ferroelectric films, as well as quality control in the construction of micro- and nano-fluidics devices
Possible complex annihilation and B -> K pi direct CP asymmetry
We point out that a sizable strong phase could be generated from the penguin
annihilation in the soft-collinear effective theory for B meson decays. Keeping
a small scale suppressed by O(Lambda/m_b), Lambda being a hadronic scale and
m_b the b quark mass, in the denominators of internal particle propagators
without expansion, the resultant strong phase can accommodate the data of the
B^0 -> K^-+ pi^+- direct CP asymmetry. Our study reconciles the opposite
conclusions on the real or complex penguin annihilation amplitude drawn in the
soft-collinear effective theory and in the perturbative QCD approach based on
k_T factorization theorem.Comment: 8 pages, 1 figure, added reference
Human treelike tubular structure segmentation: A comprehensive review and future perspectives
Various structures in human physiology follow a treelike morphology, which often expresses complexity at very fine scales. Examples of such structures are intrathoracic airways, retinal blood vessels, and hepatic blood vessels. Large collections of 2D and 3D images have been made available by medical imaging modalities such as magnetic resonance imaging (MRI), computed tomography (CT), Optical coherence tomography (OCT) and ultrasound in which the spatial arrangement can be observed. Segmentation of these structures in medical imaging is of great importance since the analysis of the structure provides insights into disease diagnosis, treatment planning, and prognosis. Manually labelling extensive data by radiologists is often time-consuming and error-prone. As a result, automated or semi-automated computational models have become a popular research field of medical imaging in the past two decades, and many have been developed to date. In this survey, we aim to provide a comprehensive review of currently publicly available datasets, segmentation algorithms, and evaluation metrics. In addition, current challenges and future research directions are discussed
Enhancement of type 1 interferon induction with drug and radiation treatments to increase anti-tumor immunity
https://openworks.mdanderson.org/sumexp21/1185/thumbnail.jp
Possible Way to Synthesize Superheavy Element Z=117
Within the framework of the dinuclear system model, the production of
superheavy element Z=117 in possible projectile-target combinations is analyzed
systematically. The calculated results show that the production cross sections
are strongly dependent on the reaction systems. Optimal combinations,
corresponding excitation energies and evaporation channels are proposed in this
letter, such as the isotopes ^{248,249}Bk in ^{48}Ca induced reactions in 3n
evaporation channels and the reactions ^{45}Sc+^{246,248}Cm in 3n and 4n
channels, and the system ^{51}V+^{244}Pu in 3n channel.Comment: 10 pages, 4 figures, 1 tabl
Region-based evidential deep learning to quantify uncertainty and improve robustness of brain tumor segmentation
Despite recent advances in the accuracy of brain tumor segmentation, the results still suffer from low reliability and robustness. Uncertainty estimation is an efficient solution to this problem, as it provides a measure of confidence in the segmentation results. The current uncertainty estimation methods based on quantile regression, Bayesian neural network, ensemble, and Monte Carlo dropout are limited by their high computational cost and inconsistency. In order to overcome these challenges, Evidential Deep Learning (EDL) was developed in recent work but primarily for natural image classification and showed inferior segmentation results. In this paper, we proposed a region-based EDL segmentation framework that can generate reliable uncertainty maps and accurate segmentation results, which is robust to noise and image corruption. We used the Theory of Evidence to interpret the output of a neural network as evidence values gathered from input features. Following Subjective Logic, evidence was parameterized as a Dirichlet distribution, and predicted probabilities were treated as subjective opinions. To evaluate the performance of our model on segmentation and uncertainty estimation, we conducted quantitative and qualitative experiments on the BraTS 2020 dataset. The results demonstrated the top performance of the proposed method in quantifying segmentation uncertainty and robustly segmenting tumors. Furthermore, our proposed new framework maintained the advantages of low computational cost and easy implementation and showed the potential for clinical application
Phenolic Compound Profiles in Skins of White Wine and Table Grape Cultivars Grown in the National Grape Germplasm Resource Nursery of China
The phenolic compound profiles in the skins of white grapes, containing ten wine grape and six table grapecultivars grown in the National Grape Germplasm Resource Nursery at the Zhengzhou Fruit ResearchInstitute of China, were investigated using ultra-high performance liquid chromatography coupled withmass spectrometry (UHPLC-MS/MS). The objective of this study was to evaluate if phenolic compoundprofiles can be used as indictors to differentiate the quality of wine and table grape cultivars. Significantdifferences in phenolic compound profiles were observed among these grape cultivar skins. The highestcontent of total hydroxybenzoic acids, total hydroxycinnamic acids, total flavan-3-ols, total flavones andflavonols and total stilbenes was observed in the skin of the Canada Muscat, Rommel, Kadin parmac,Bacchus and Silvaner cultivars respectively. A great compositional difference was observed among thesegrape cultivars regarding the individual hydroxycinnamic acids and flavonols. Cluster analysis showed thatthree table grape cultivars, namely Canada Muscat, Rommel and Kadin parmac, possessed significantlydifferent phenolic compound profiles compared to the other grape cultivars. These results suggested thatphenolic compound patterns and contents played important roles in evaluating the quality of table andwine grapes and might provide useful information on grape breeding and winemaking in China
factorization of exclusive processes
We prove factorization theorem in perturbative QCD (PQCD) for exclusive
processes by considering and . The relevant form factors are expressed as the convolution of hard
amplitudes with two-parton meson wave functions in the impact parameter
space, being conjugate to the parton transverse momenta . The point is
that on-shell valence partons carry longitudinal momenta initially, and acquire
through collinear gluon exchanges. The -dependent two-parton wave
functions with an appropriate path for the Wilson links are gauge-invariant.
The hard amplitudes, defined as the difference between the parton-level
diagrams of on-shell external particles and their collinear approximation, are
also gauge-invariant. We compare the predictions for two-body nonleptonic
meson decays derived from factorization (the PQCD approach) and from
collinear factorization (the QCD factorization approach).Comment: 11 pages, REVTEX, 5 figure
Safe Control and Learning Using Generalized Action Governor
This paper introduces the Generalized Action Governor, which is a supervisory
scheme for augmenting a nominal closed-loop system with the capability of
strictly handling constraints. After presenting its theory for general systems
and introducing tailored design approaches for linear and discrete systems, we
discuss its application to safe online learning, which aims to safely evolve
control parameters using real-time data to improve performance for uncertain
systems. In particular, we propose two safe learning algorithms based on
integration of reinforcement learning/data-driven Koopman operator-based
control with the generalized action governor. The developments are illustrated
with a numerical example.Comment: 10 pages, 4 figure
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