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Time-resolved imaging of molecules and materials made of light elements is an emerging field of transmission electron microscopy (TEM), and the recent development of direct electron detection cameras, capable of taking as many as 1,600 fps, has potentially broadened the scope of the time-resolved TEM imaging in chemistry and nanotechnology. However, such a high frame rate reduces electron dose per frame, lowers the signal-to-noise ratio (SNR), and renders the molecular images practically invisible. Here, we examined image noise reduction to take the best advantage of fast cameras and concluded that the Chambolle total variation denoising algorithm is the method of choice, as illustrated for imaging of a molecule in the 1D hollow space of a carbon nanotube with ~1 ms time resolution. Through the systematic comparison of the performance of multiple denoising algorithms, we found that the Chambolle algorithm improves the SNR by more than an order of magnitude when applied to TEM images taken at a low electron dose as required for imaging at around 1,000 fps. Open-source code and a standalone application to apply Chambolle denoising to TEM images and video frames are available for download.
Sen attached to each $p$-adic Galois representation of a $p$-adic field a multiset of numbers called generalized Hodge–Tate weights. In this paper, we discuss a rigidity of these numbers in a geometric family. More precisely, we consider a $p$-adic local system on a rigid analytic variety over a $p$-adic field and show that the multiset of generalized Hodge–Tate weights of the local system is constant. The proof uses the $p$-adic Riemann–Hilbert correspondence by Liu and Zhu, a Sen–Fontaine decompletion theory in the relative setting, and the theory of formal connections. We also discuss basic properties of Hodge–Tate sheaves on a rigid analytic variety.
To investigate the relationship between the severities of symptom dimensions in obsessive-compulsive disorder (OCD) and white matter alterations.
We applied tract-based spatial statistics for diffusion tensor imaging (DTI) acquired by 3T magnetic resonance imaging. First, we compared fractional anisotropy (FA) between 20 OCD patients and 30 healthy controls (HC). Then, applying whole brain analysis, we searched the brain regions showing correlations between the severities of symptom dimensions assessed by Obsessive-Compulsive Inventory-Revised and FA in all participants. Finally, we calculated the correlations between the six symptom dimensions and multiple DTI measures [FA, axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD)] in a region-of-interest (ROI) analysis and explored the differences between OCD patients and HC.
There were no between-group differences in FA or brain region correlations between the severities of symptom dimensions and FA in any of the participants. ROI analysis revealed negative correlations between checking severity and left inferior frontal gyrus white matter and left middle temporal gyrus white matter and a positive correlation between ordering severity and right precuneus in FA in OCD compared with HC. We also found negative correlations between ordering severity and right precuneus in RD, between obsessing severities and right supramarginal gyrus in AD and MD, and between hoarding severity and right insular gyrus in AD.
Our study supported the hypothesis that the severities of respective symptom dimensions are associated with different patterns of white matter alterations.
Elemental distributions in a magnetic multilayer system with the structure Si substrate/Ta/NiFe/Ru/CoFeB/Ru/NiFe were studied using atom probe tomography (APT) along different analysis directions. The distributions of Ru and B atoms, which require a high evaporation field, were strongly influenced by the APT analysis direction. In particular, B in the CoFeB layer appeared near the interface with the lower Ru layer when the analysis was anti-parallel to the film growth direction, while B atoms were observed at the other side of the CoFeB layer when the analysis was parallel to the film growth direction. Moreover, when the analysis was perpendicular to the film growth direction, a homogenous distribution of B atoms was found within the CoFeB layer. Owing to this B behavior, the underlying Ru layer was affected in both of these analysis directions. In APT measurements of such a multilayer system composed of a stack of different evaporation field materials, evaluation of the elemental distribution around interfaces should be performed from more than one analysis direction.
We investigated how changes in the method of supplying Sn and Fe carbon nanocoil (CNC) catalysts affected the results of chemical vapor deposition. The Sn/Fe catalysts were supplied using the following four materials: a thin Sn film, a drop-coated solution of Fe2O3, tetramethyltin (TMT) vapor, and ferrocene vapor. The CNC purity was evaluated using scanning electron microscopy. The CNC purity in the overall carbon deposit was also evaluated by analyzing the cross-section of the deposit. The CNC purity averaged over the overall carbon deposit was increased 1.5-fold by the TMT supply. We obtained a maximum CNC purity of 72% using a combination of TMT and ferrocene vapors, with Sn/Fe deposition on the substrate. Energy-dispersive x-ray spectroscopy analysis of the catalyst nanoparticles in the tips of the CNCs and carbon nanofibers (CNFs) revealed that there was a large difference in the Sn/Fe molar ratios for the angular- and round-type CNFs.
We review the results of very early phase optical follow-up observations of recent gamma-ray bursts (GRBs) with the multi-color optical telescopes “MITSuME”. The MITSuME telescopes were designed to perform “real time” and “automatic” follow-up observations prompted by the GCN alerts via the Internet. The rapidly slewing equatorial mounts allow MITSuME to start photometric observations within 100 seconds after the trigger for several GRBs. In particular, we detected a brightening just after the trigger for two GRBs. These phenomena could be interpreted as the “on-set” of afterglow. In this paper we summarize these optical observations with a brief interpretation.
In this paper, we report infrared absorption studies of HfO2, HfO2/Si interface and Hf(1−x)SixOy. Both HfO2 crystallization and SiO2 formation at the interface can be clearly detected in the absorption spectra in the far and middle infrared regions, respectively. By measuring the intensity change and the peak shift of infrared absorption spectra as functions of annealing temperature and time together with XRD patterns, we discuss a difference of the amorphous structure between HfO2 and SiO2, and also show an evolution of HfO2 crystallization in the monoclinic phase up to 1000 °C. On the other hand, it is shown that the interfacial SiO2 layer is qualitatively similar to the thermally grown SiO2. Furthermore, it is demonstrated that a Si incorporation into HfO2 film significantly changes the IR absorption spectra, and that the Hf(1−x)SixOy film is phase-separated with an appearance of modified monoclinic phase by higher temperature annealing.
Key issues of heavy ion beam (HIB) inertial confinement fusion
(ICF) include an efficient stable beam transport, beam focusing,
uniform fuel pellet implosion, and so on. To realize a HIB fine
focus on a fuel pellet, space-charge neutralization of incident
focusing HIB is required at the HIB final transport just after
a final focusing element in an HIB accelerator. In this article,
an insulator annular tube guide is proposed at the final transport
part, through which a HIB is transported. The physical mechanism
of HIB charge neutralization based on an insulator annular guide
is as follows: A local electric field created by HIB induces
local discharges, and plasma is produced on the insulator inner
surface. Then electrons are extracted from the plasma by the
HIB net space charge. The electrons emitted neutralize the HIB
space charge well.
We investigated the third-order nonlinear optical response of a Gay-Berne system at the isotropic, nematic, and smectic phases by molecular dynamics simulation. The components of the optical response were calculated for the three different axes with respect to the director of the system, separately. In the nematic phase, in particular, we observed that the response function does not vanish at long times. This means that the orientation of the director of the system is permanently changed by an instant irradiation of polarized light, as a result of third-order nonlinear optical response. In the smectic phase, however, all the components of the response function decay quickly. Our results give a theoretical background at molecular level on the interpretation of the reported experimental observations of peculiar dynamics of liquid crystalline systems at irradiation of laser lights.
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