Subcycle control of valley-selective excitation via dynamical Franz-Keldysh effect in WSe2_2 monolayer

This study performed first-principles calculations based on the time-dependent density functional theory to control the valley degree of freedom relating to the dynamical Franz-Keldysh effect (DFKE) in a monolayer of transition metal dichalcogenide. By mimicking the attosecond transient absorption spectroscopy, we performed numerical pump-probe experiments to observe DFKE around the $K$ or $K'$ valley in WSe$_2$ monolayer with a linearly-polarized pump field and a circularly-polarized probe pulse. We found that the circularly-polarized probe pulse with a given helicity can selectively observe the transient conductivity modulated by DFKE in each valley. The transient conductivity and excitation probability around each valley oscillate with the pump field frequency $\Omega$. The phases of the $\Omega$ oscillation for the $K$ and $K'$ valleys are opposite to each other. Furthermore, the pump-driven DFKE alters the absorption rate of WSe$_2$ monolayer and yields the valley-dependent $\Omega$ oscillation of the electron excitation induced by the pump plus probe field. With a simplified two-band model, we identified the $\Omega$ oscillation of the off-diagonal conductivity caused by the band asymmetry around the valleys as the physical mechanism responsible for the valley-selective DFKE.Comment: 10 pages, 9 figure

The diagnosis of delayed expanding traumatic pseudoaneurysm of thoracic aorta caused by self-inflicted penetrating injury with crossbow bolt: A case report

Introduction and importance: Penetrating chest trauma caused by a crossbow bolt is very rare. Herein, we report a successfully treated patient who attempted suicide by directing a crossbow to the chest cavity and developed an expanding pseudoaneurysm of the thoracic aorta during eight-day follow up. Case presentation: A 51-year-old male was admitted to the emergency department after firing a crossbow bolt twice into his left chest. At admission, the patient was hemodynamically stable and maintaining oxygenation. The bolt had already been removed from the body. Contrast-enhanced computed tomography (CT) revealed a cavity pseudoaneurysm 2.5 mm in size in the aortic arch. Three-dimensional reconstruction of the CT demonstrated wound tracts showing probable damage by the bolt. The patient was admitted to the emergency department for careful observation and transferred to the psychiatric ward on day two. Follow-up contrast-enhanced CT on day eight demonstrated rapid expansion of the pseudoaneurysm from 2.5 mm to 4.0 mm in size. We performed thoracic endovascular aortic repair (TEVAR) on day 13. The patient was uneventfully discharged on the 20th hospital day. Clinical discussion: Emergency physicians should be aware that damage to the surrounding tissue may be accompanied by delayed expansion of an aortic pseudoaneurysm, even if the bolts do not cause direct aortic wall injury. Conclusion: This case suggests that understanding the injury mechanism, confirming the tract of the bolts, and carefully exploring traumatic pseudoaneurysm can lead to a less invasive operation due to early detection

Propagation effects in high-harmonic generation from dielectric thin films

Theoretical investigation is conducted of high-order harmonic generation (HHG) in silicon thin films to elucidate the effect of light propagation in reflected and transmitted waves. The first-principles simulations are performed of the process in which an intense pulsed light irradiates silicon thin films up to 3 $\mu$m thickness. Our simulations are carried within the time-dependent density functional theory (TDDFT) with the account of coupled dynamics of the electromagnetic fields and the electronic motion. It was found that the intensity of transmission HHG gradually decreases with the thickness, while the reflection HHG becomes constant from a certain thickness. Detailed analyses show that transmission HHG have two origins: the HHG generated near the front edge and propagating to the back surface, and that generated near the back edge and emitted directly. The dominating mechanism of the transmission HHG is found to depend on the thickness of the thin film and the frequency of the HHG. At the film thickness of 1 $\mu$m, the transmission HHG with the frequency below 20 eV is generated near the back edge, while that with the frequency above 20 eV is generated near the front edge and propagates from there to the back surface.Comment: 11 pages, 8 figure

Remitting Seronegative Symmetrical Synovitis with Pitting Edema Syndrome in a Chronic Hemodialysis Patient

A 75-year-old male who was undergoing chronic hemodialysis developed abrupt-onset pitting edema and pain in the dorsum of both hands and feet. Biochemical analysis disclosed increased C-reactive protein, and negative rheumatoid factor and antinuclear antibody. Radiological examination showed no bony erosion. Computed tomography and gallium scintigraphy revealed no active infection or neoplasms. The clinical diagnosis was remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome. The pitting edema and inflammatory response quickly subsided after low-dose prednisolone therapy. This case demonstrates that RS3PE syndrome could be a differential diagnosis in elderly patients undergoing dialysis who develop pitting edema and joint pain

Accretion Geometry of the Low-Mass X-ray Binary Aquila X-1 in the Soft and Hard States

The neutron-star Low-Mass X-ray Binary Aquila X-1 was observed seven times in total with the Suzaku X-ray observatory from September 28 to October 30 in 2007, in the decaying phase of an outburst. In order to constrain the flux-dependent accretion geometry of this source over wider energy bands than employed in most of previous works, the present study utilized two out of the seven data sets. The 0.8-31 keV spectrum on September 28, taken with the XIS and HXD-PIN for an exposure of 13.8 ks, shows an absorbed 0.8-31 keV flux of $3.6\times 10^{-9}$ erg s$^{-1}$ cm$^{-2}$, together with typical characteristics of the soft state of this type of objects. The spectrum was successfully explained by an optically-thick disk emission plus a Comptonized blackbody component. Although these results are in general agreement with previous studies, the significance of a hard tail recently reported using the same data was inconclusive in our analysis. The spectrum acquired on October 9 for an exposure of 19.7 ks was detected over a 0.8-100 keV band with the XIS, HXD-PIN, and HXD-GSO, at an absorbed flux of $8.5\times 10^{-10}$ erg s$^{-1}$ cm$^{-2}$ (in 0.8-100 keV). It shows characteristics of the hard state, and was successfully explained by the same two continuum components but with rather different parameters including much stronger thermal Comptonization, of which the seed photon source was identified with blackbody emission from the neutron-star surface. As a result, the accretion flow in the hard state is inferred to take a form of an optically-thick and geometrically-thin disk down to a radius of $21\pm 4$ km from the neutron star, and then turn into an optically-thin nearly-spherical hot flow.Comment: PASJ in publish. 12 pages including 16 figure

Stabilization of SF₅⁻ with Glyme-Coordinated Alkali Metal Cations

The stabilization of complex fluoroanions derived from weakly acidic parent fluorides is a significant and ongoing challenge. The [SF₅]⁻ anion is recognized as one such case, and only a limited number of [SF₅]⁻ salts are known to be stable at room temperature. In the present study, glyme-coordinated alkali metal cations (K⁺, Rb⁺, and Cs⁺) are employed to stabilize [SF₅]⁻, which provides a simple synthetic route to a [SF₅]⁻ salt. The reactivities of KF and RbF with SF₄ are significantly enhanced by complexation with G4, based on Raman spectroscopic analyses. A new room-temperature stable salt, [Cs(G4)₂][SF₅] (G4 = tetraglyme), was synthesized by stoichiometric reaction of CsF, G4, and SF₄. The vibrational frequencies of [SF₅]⁻ were assigned based on quantum chemical calculations, and the shift of the G4 breathing mode accompanying coordination to metal cations was confirmed by Raman spectroscopy. Single-crystal X-ray diffraction revealed that Cs⁺ is completely isolated from [SF₅]⁻ by two G4 ligands and [SF₅]⁻ is disordered along the crystallographic two-fold axis. Hirshfeld surface analysis reveals that the H···H interaction between two neighboring [Cs(G4)₂]⁺ moieties is more dominant on the Hirshfeld surface than the interaction between the H atom in glyme molecules and the F atom in [SF₅]⁻, providing a CsCl-type structural model where the large and spherical [Cs(G4)₂]⁺ cations contact each other and the [SF₅]⁻ anions occupy interstitial spaces in the crystal lattice. The [SF₅]⁻ anion, combined with [Cs(G4)₂]⁺, exhibits a very limited deoxofluorinating ability toward hydroxyl groups in both neat conditions and THF solutions

Data-Driven Sensor Selection Method Based on Proximal Optimization for High-Dimensional Data With Correlated Measurement Noise

The present paper proposes a data-driven sensor selection method for a high-dimensional nondynamical system with strongly correlated measurement noise. The proposed method is based on proximal optimization and determines sensor locations by minimizing the trace of the inverse of the Fisher information matrix under a block-sparsity hard constraint. The proposed method can avoid the difficulty of sensor selection with strongly correlated measurement noise, in which the possible sensor locations must be known in advance for calculating the precision matrix for selecting sensor locations. The problem can be efficiently solved by the alternating direction method of multipliers, and the computational complexity of the proposed method is proportional to the number of potential sensor locations when it is used in combination with a low-rank expression of the measurement noise model. The advantage of the proposed method over existing sensor selection methods is demonstrated through experiments using artificial and real datasets