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Molecular-beam spectroscopy with an infinite interferometer: spectroscopic resolution and accuracy
No full textAn interferometer with effectively infinite maximum optical path difference removes the dominant resolution limit for interferometric spectroscopy. We present mass-correlated rotational Raman spectra that represent the world's highest resolution scanned interferometric data and discuss the current and expected future limitations in achievable spectroscopic performance
Facilely full-end-capping engineering promotes high-performance organic solar cells with simultaneously improved efficiency and stability
No full textMain-chain construction and side-chain modification are general strategies to design polymer donors for organic solar cell (OSCs), but they always suffer from deliberate molecular design and tedious synthesis. Here, we employ full-end-capping engineering, a facile and versatile strategy to boost both efficiency and stability for nonfullerene OSCs. A series of full-end-capped polymer donors are obtained by a simple end-capping reaction right after the polymerization in one-pot. It is found that the end-capping groups not only completely remove the unreacted terminal defects in the polymer chains, but also well-manipulate the molecular orientation, filmforming process and resulting morphology, optimize the charge dynamics, and reduce non-radiative energy loss. The device with full-end-capped PM6-T:Y6-based obtains an impressive efficiency of 17.11%, showing allover improved device parameters and long-term stability than unend-capped PM6:Y6-based device (15.96%). Notably, PM6-T:BTP-eC9-based device reaches a efficacy of 18.45%, among the highest performance of BTP-eC9based devices
Bianchi modular symbols and p-adic L-functions
No full textIn the present paper, we prove that the first homology group of Bianchi 3-fold is generated by the special Bianchi modular symbols. Also, we construct the integral valued p-adic L -function of p-ordinary Bianchi Hecke eigenforms by taking the Lefschetz-Poincare Pairing of the cohomology class attached to Bianchi modular forms and Bianchi modular symbols on Bianchi 3-folds. By using the homology generation result, we prove that the mu-invariant of some isotopic components of the p-adic L-function of certain Bianchi Hecke eigenforms vanishes for a positive proportion of ordinary prime ideals. The main ingredient of the proof of the generation result is analyzing the fast convergent series expression of the integration of the Bianchi modular forms along the special modular symbols. (c) 2023 Elsevier Inc. All rights reserved
Lithium pollution reduction of a lithium charge stripper using a skimmer
No full textThis study proposes a method to reduce the beamline pollution caused by lithium gas generated when a lithium film is formed while driving a heavy ion accelerator. To this end, the liquefaction and solidification of lithium vapor are utilized, and a skimmer is installed on the beamline to reduce pollution through contact with lithium vapor. Particularly, three curved skimmers were installed in consideration of the length of the beamline to increase the contact area. Analysis results revealed that the lithium film forms lithium gas at 0.5 g/s. When the gas flow generated is converted into a vacuum pump, the vacuum degree of the beam line is 3.88 x 10(-7) mbar, which is 1/74 of the vacuum degree of the charge stripper, and approximately 30% lower than that of a straight-type skimmer. Additionally, the flow velocity of lithium particle is 3 x 10(-11) m/s, and it takes 1260 years to reach the beamline; accordingly, the results suggest that the use of a curved skimmer will enable the optimal operation of the beamline without any lithium contamination
Chiral electroluminescence from thin-film perovskite metacavities
No full textChiral light sources realized in ultracompact device platforms are highly desirable for various applications. Among active media used for thin-film emission devices, lead-halide perovskites have been extensively studied for photoluminescence due to their exceptional properties. However, up to date, there have been no demonstrations of chiral electroluminescence with a substantial degree of circular polarization (DCP) based on perovskite materials, being critical for the development of practical devices. Here, we propose a concept of chiral light sources based on a thin-film perovskite metacavity and experimentally demonstrate chiral electroluminescence with a peak DCP approaching 0.38. We design a metacavity created by a metal and a dielectric metasurface supporting photonic eigenstates with a close-to-maximum chiral response. Chiral cavity modes facilitate asymmetric electroluminescence of pairs of left and right circularly polarized waves propagating in the opposite oblique directions. The proposed ultracompact light sources are especially advantageous for many applications requiring chiral light beams of both helicities
Correlation between solvent composition and materials properties of organohydrogels prepared by solvent displacement
No full textOwing to their tunable functionality, structural flexibility, and biocompatibility, gels are widely utilized as active materials in applications, such as biomedical, sensors, and energy devices. Especially hydrogels, generally comprised of water over 80 vol%, are emphasized as attractive candidates for suggested applications. However, most devices based on hydrogels suffer from drying and freezing under practical operation environments. To overcome these issues, organohydrogels are proposed as good alternatives with improved durability. Although many organohydrogels with various polymer networks are reported, the effects of solvent system design on the properties of organohydrogels are still not conclusive. Here, we investigated the correlation between the solvent system design of organohydrogels and their properties, particularly in terms of rheological characteristics and ion conductivity. With increasing ethylene glycol content, the shear storage modulus and complex viscosity of the organohydrogels decrease sharply, possibly owing to the decrease in metal-carboxylate coordination in the gel network. The ion conductivity of the organohydrogels gradually decreases with increasing ethylene glycol content, owing to the ion conductivity trends of pure water and pure ethylene glycol ionic solution. Insight into the correlation between the solvent system design and properties of organohydrogels will enable the preparation of optimal organohydrogels for various processes and applications
Domain-specific valuation of university technologies using bibliometrics, Jonckheere-Terpstra tests, and data envelopment analysis
No full textAlthough university technology licencing has been the subject of many studies, a major gap remains in the literature regarding ways to assess the economic value of university technologies. We propose an analytical framework for the domain-specific valuation of university technologies using bibliometrics, Jonckheere-Terpstra tests, and data envelopment analysis (DEA). First, 18 potential quantitative indicators of the economic value of university technologies are extracted from technology transaction, patent, and publication databases using bibliometrics. Second, given the heterogeneity across technology fields, significant indicators suited to a tech-nology field of interest are identified using the Jonckheere-Terpstra tests. Third, a composite indicator is developed as a proxy for the economic value of university technologies using the DEA cross-efficiency method. Finally, the validity and utility of the analytical framework are examined using correlation analysis and the Jonckheere-Terpstra test. Accordingly, we explore the different implications of quantitative indicators in the valuation of university technologies across technology fields. A case study of the technologies registered in the Office of Technology Licensing at Stanford University confirms that the proposed analytical framework is valuable as a complementary tool for the valuation of university technologies
Structures of Vac8-containing protein complexes reveal the underlying mechanism by which Vac8 regulates multiple cellular processes
No full textVac8, a yeast vacuolar protein with armadillo repeats, mediates various cellular processes by changing its binding partners; however, the mechanism by which Vac8 differentially regulates these processes remains poorly understood. Vac8 interacts with Nvj1 to form the nuclear???vacuole junction (NVJ) and with Atg13 to mediate cytoplasm-to-vacuole targeting (Cvt), a selective autophagy-like pathway that delivers cytoplasmic aminopeptidase I directly to the vacuole. In addition, Vac8 associates with Myo2, a yeast class V myosin, through its interaction with Vac17 for vacuolar inheritance from the mother cell to the emerging daughter cell during cell divisions. Here, we determined the X-ray crystal structure of the Vac8???Vac17 complex and found that its interaction interfaces are bipartite, unlike those of the Vac8???Nvj1 and Vac8???Atg13 complexes. When the key amino acids present in the interface between Vac8 and Vac17 were mutated, vacuole inheritance was severely impaired in vivo. Furthermore, binding of Vac17 to Vac8 prevented dimerization of Vac8, which is required for its interactions with Nvj1 and Atg13, by clamping the H1 helix to the ARM1 domain of Vac8 and thereby preventing exposure of the binding interface for Vac8 dimerization. Consistently, the binding affinity of Vac17-bound Vac8 for Nvj1 or Atg13 was markedly lower than that of free Vac8. Likewise, free Vac17 had no affinity for the Vac8???Nvj1 and Vac8???Atg13 complexes. These results provide insights into how vacuole inheritance and other Vac8-mediated processes, such as NVJ formation and Cvt, occur independently of one another
Single Quantum Dot Selection and Tailor-Made Photonic Device Integration using a Nanoscale-Focus Pinspot
No full textAmong the diverse platforms of quantum light sources, epitaxially grown semiconductor quantum dots (QDs) are one of the most attractive workhorses for realizing quantum photonic technologies owing to their outstanding brightness and scalability. However, the spatial and spectral randomness of most QDs severely hinders the construction of large-scale photonic platforms. In this work, a methodology is presented to deterministically integrate single QDs with tailor-made photonic structures. A nondestructive luminescence picking method termed as nanoscale-focus pinspot (NFP) is applied using helium-ion microscopy to reduce the luminous QD density while retaining the surrounding medium. A single QD emission is only extracted out of the high-density ensemble QDs. Then the tailor-made photonic structure of a circular Bragg reflector (CBR) is designed and deterministically integrated with the selected QD. Given that the microscopy can image with nanoscale resolution and apply NFP in situ, photonic devices can be deterministically fabricated on target QDs. The extraction efficiency of the NFP-selected QD emission is improved by 25 times after the CBR integration. Since the NFP method only controls the luminescence without destroying the medium, it is applicable to various photonic structures such as photonic waveguides or photonic crystal cavities regardless of materials
Effects of a single roughness element on Venturi cavitation
No full textIn this study, we investigate the effects of a single roughness element on Venturi cavitation.
The single roughness element of hemispherical shape is installed at the throat inlet of a Venturi tube.
Since the wake behind the roughness element induces an additional pressure drop, cavitation inception occurs at a higher Cavitation number for the Venturi model with the single roughness element than for the Venturi model with no roughness. Cavitation bubbles form along the wake of the roughness element and lengthen in the streamwise direction as the Cavitation number decreases, forming a longitudinal cavitation. With a further decrease in the Cavitation number, the longitudinal cavitation bubble merges with the sheet cavitation initiated from the exit edge of the Venturi tube throat, followed by the shedding of cloud cavitation. The merging of the longitudinal cavitation and sheet cavitation is accompanied by a sudden decrease in the discharge coefficient and an increase in the pressure loss coefficient as it chokes the flow inside the Venturi tube