Effects of spin-orbit interactions in condensed matter are an important and rapidly evolving topic. Strong competition between spin-orbit, on-site Coulomb and crystalline electric field interactions ...in iridates drives exotic quantum states that are unique to this group of materials. In particular, the 'Jeff = ½' Mott state served as an early signal that the combined effect of strong spin-orbit and Coulomb interactions in iridates has unique, intriguing consequences. In this Key Issues Review, we survey some current experimental studies of iridates. In essence, these materials tend to defy conventional wisdom: absence of conventional correlations between magnetic and insulating states, avoidance of metallization at high pressures, 'S-shaped' I-V characteristic, emergence of an odd-parity hidden order, etc. It is particularly intriguing that there exist conspicuous discrepancies between current experimental results and theoretical proposals that address superconducting, topological and quantum spin liquid phases. This class of materials, in which the lattice degrees of freedom play a critical role seldom seen in other materials, evidently presents some profound intellectual challenges that call for more investigations both experimentally and theoretically. Physical properties unique to these materials may help unlock a world of possibilities for functional materials and devices. We emphasize that, given the rapidly developing nature of this field, this Key Issues Review is by no means an exhaustive report of the current state of experimental studies of iridates.
Abstract
We study the pulsar energy-dependent
γ
-ray light curves and spectra from curvature radiation in the dissipative magnetospheres. The dissipative magnetospheres with the combined force-free ...(FFE) and Aristotelian are computed by a pseudo-spectral method with a high-resolution simulation in the rotating coordinate system, which produces a near-FFE field structure with the dissipative region only near the equatorial current sheet outside the light cylinder. We use the test-particle trajectory method to compute the energy-dependent
γ
-ray light curves and phase-average and phase-resolved spectra by including both the accelerating electric field and radiation reaction. The predicted energy-dependent
γ
-ray light curves and spectra are then compared with those of the Vela pulsar observed by Fermi. Our results can generally reproduce the observed trends of the energy-dependent
γ
-ray light curves and spectra for the Vela pulsar.
Abstract
We explore the multiwavelength radiation properties of the light curves and energy spectra in the dissipative magnetospheres of pulsars. The dissipative magnetospheres are simulated by the ...pseudo-spectral method with the combined force-free and Aristotelian electrodynamics, which can produce self-consistent accelerating electric fields mainly distributed in the equatorial current sheet outside the light cylinder. The multiwavelength light curves and spectra are computed by using the multiple emission mechanisms of both the primary particles accelerated by the accelerating electric fields in the equatorial current sheet and the secondary pairs with an assumed distribution spectrum. We then compare the predicted multiwavelength light curves and spectra with the observed data from the Crab, Vela, and Geminga pulsars. Our modeling results can systematically reproduce the observed trends of the multiwavelength light curves and the spectra for these three pulsars well.
This book is aimed at advanced undergraduates, graduate students and other researchers who possess an introductory background in materials physics and/or chemistry, and an interest in the physical ...and chemical properties of novel materials, especially transition metal oxides. New materials often exhibit novel phenomena of great fundamental and technological importance. Contributing authors review the structural, physical and chemical properties of notable 4d- and 5d-transition metal oxides discovered over the last 10 years. These materials exhibit extraordinary physical properties that differ significantly from those of the heavily studied 3d-transition metal oxides, mainly due to the relatively strong influence of the spin-orbit interaction and orbital order in 4d- and 5d materials.
As a retouching manipulation, contrast enhancement is typically used to adjust the global brightness and contrast of digital images. Malicious users may also perform contrast enhancement locally for ...creating a realistic composite image. As such it is significant to detect contrast enhancement blindly for verifying the originality and authenticity of the digital images. In this paper, we propose two novel algorithms to detect the contrast enhancement involved manipulations in digital images. First, we focus on the detection of global contrast enhancement applied to the previously JPEG-compressed images, which are widespread in real applications. The histogram peak/gap artifacts incurred by the JPEG compression and pixel value mappings are analyzed theoretically, and distinguished by identifying the zero-height gap fingerprints. Second, we propose to identify the composite image created by enforcing contrast adjustment on either one or both source regions. The positions of detected blockwise peak/gap bins are clustered for recognizing the contrast enhancement mappings applied to different source regions. The consistency between regional artifacts is checked for discovering the image forgeries and locating the composition boundary. Extensive experiments have verified the effectiveness and efficacy of the proposed techniques.
We comprehensively analyzed clinical, genomic, and transcriptomic data of a cohort of 465 primary triple-negative breast cancer (TNBC). PIK3CA mutations and copy-number gains of chromosome 22q11 were ...more frequent in our Chinese cohort than in The Cancer Genome Atlas. We classified TNBCs into four transcriptome-based subtypes: (1) luminal androgen receptor (LAR), (2) immunomodulatory, (3) basal-like immune-suppressed, and (4) mesenchymal-like. Putative therapeutic targets or biomarkers were identified among each subtype. Importantly, the LAR subtype showed more ERBB2 somatic mutations, infrequent mutational signature 3 and frequent CDKN2A loss. The comprehensive profile of TNBCs provided here will serve as a reference to further advance the understanding and precision treatment of TNBC.
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•We build the genomic and transcriptomic landscape of 465 primary TNBCs•Chinese TNBC cases demonstrate more PIK3CA mutations and LAR subtype•Transcriptomic data classify TNBCs into four subtypes•Multi-omics profiling identifies potential targets within specific TNBC subtypes
Jiang et al. characterize primary Chinese triple-negative breast cancer (TNBC) and classify it into four subtypes. They find that these TNBCs have more frequent PIK3CA mutations and chromosome 22q11 copy-number gains than non-Asian TNBCs and that the LAR subtype has more ERBB2 somatic mutations and CDKN2A loss.
Necking propagation (NP) is an important phenomenon that is facilitated by the superductility of many materials, although necking is often considered to be a type of unstable and heterogeneous ...deformation under tensile loading. In this study, the NP of samples produced with injection molding of polypropylene (PP) and high‐density polyethylene (HDPE) blends with or without a blowing agent was investigated by standard tensile testing, and the foam morphology and cellular structure were characterized with scanning electron microscopy. It was found that the foam parts fabricated with the PP/HDPE blends had the ability to be superductile under a low tensile test speed, which was attributed to the necking spreading throughout the tested gauge section stably and reliably. However, the NP of the foam PP/HDPE blend samples strongly depended on the distribution of the cellular foam. To investigate the relationship between the cellular structure and NP, a design of experiment approach based on the Taguchi method was used to fabricate many samples with different foam structures. The tensile test results of these samples suggested that the cellular uniformity, which was determined based on the statistical results of the fracture surface morphology, played an important role in the NP. The results suggested that there is a close relationship between the NP and the cellular uniformity. Using nonlinear fitting, it was straightforward to obtain a model between the NP length and cellular uniformity index for PP/HDPE molded foam parts.
Operation speed and coherence time are two core measures for the viability of a qubit. Strong spin-orbit interaction (SOI) and relatively weak hyperfine interaction make holes in germanium (Ge) ...intriguing candidates for spin qubits with rapid, all-electrical coherent control. Here we report ultrafast single-spin manipulation in a hole-based double quantum dot in a germanium hut wire (GHW). Mediated by the strong SOI, a Rabi frequency exceeding 540 MHz is observed at a magnetic field of 100 mT, setting a record for ultrafast spin qubit control in semiconductor systems. We demonstrate that the strong SOI of heavy holes (HHs) in our GHW, characterized by a very short spin-orbit length of 1.5 nm, enables the rapid gate operations we accomplish. Our results demonstrate the potential of ultrafast coherent control of hole spin qubits to meet the requirement of DiVincenzo's criteria for a scalable quantum information processor.
In the present study, the effect of low-temperature thermal and alkali pretreatments on biodegradability of waste activated sludge was evaluated. Combined with low-temperature thermal pretreatment ...(80 °C), varied proportions of a mixed alkali (i.e., a mixture of NaOH and Ca OH2) were added. The pretreatment procedures were conducted in different orders; thermal-alkali pretreatment (TAP), simultaneous thermal and alkali pretreatment (STAP), and alkali-thermal pretreatment (ATP). Following pretreatment, the sludge with the alkali-thermal pretreatment was most considerably dissolved. The SCOD concentration was up to 18,000 mg/L in the WAS, and the dissolution rate reached 112.8%. Therefore, the anaerobic digestion (AD) performance of waste activated sludge (WAS) by mixed alkali-thermal pretreatment was investigated. With an increase in sodium hydroxide content in the mixed alkali, the cumulative methane production (CMP) of the sludge increased accordingly. The maximum CMP (i.e., 430 mL/g VS volatile solids), increased by 308.7% compared with untreated sludge and was obtained by the pretreatment of the mixed alkali (NaOH/Ca(OH)2 = 4:1) at 80 °C. The results show that low-temperature thermal treatment combined with the mixed alkali treatment can reduce the inhibitory effect of mixed alkali on AD, thereby shortening the inhibition period (6d) and increasing methane production (308.7%). The preliminary economic feasibility analysis also showed that the ATP was a cost-effective pretreatment method.
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•Low-temperature thermal-alkali pretreatment enhanced anaerobic sludge digestion.•Different orders of thermal and alkali pretreatments had different effects.•The optimum ratio of the mixed alkali was 4:1 for NaOH/Ca(OH)2.•Alkali-thermal pretreatment was optimum and the maximum CMP was 429.97 mL/g VS.
We reported a method for the synthesis of 3,3′‐disubstituted isobenzofuran‐1(3H)‐ones via the carbonyl difunctionalization of 2‐acylbenzoic acids. A range of nucleophiles was reacted with ...2‐acylbenzoic acids to furnish the functionalized isobenzofuran‐1(3H)‐ones with the factual yield range of 61–96%. The reaction uses Cs0.5H2.5PW12O40 as a catalyst and produces water as the sole by‐product. Various functional groups could be introduced to the isobenzofuran‐1(3H)‐one skeletons via the C−P/C−N/C−O/C−C bond formation, which would provide opportunities for the synthesis of potential biologically active molecules. Based on the preliminary experiments, a plausible mechanism is proposed.
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