A second-order phase transition in a physical system is associated with the emergence of an "order parameter" and a spontaneous symmetry breaking. The heavy fermion superconductor URu2Si2 has a ..."hidden order" (HO) phase below the temperature of 17.5 kelvin; the symmetry of the associated order parameter has remained ambiguous. Here we use polarization-resolved Raman spectroscopy to specify the symmetry of the low-energy excitations above and below the HO transition. We determine that the HO parameter breaks local vertical and diagonal reflection symmetries at the uranium sites, resulting in crystal field states with distinct chiral properties, which order to a commensurate chirality density wave ground state.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
A dual attention deep learning network is developed to classify three types of steel defects, locate their positions, and depict their shapes on the steel surface in an automatic and accurate manner. ...The novel pixel‐level detection algorithm called DAN‐DeepLabv3+ integrates a dual attention module into the DeepLabv3+ framework in pursue of more precise segmentation results. For one thing, the dual parallel attention module helps to explicitly model rich contextual dependencies over local feature representations in the spatial and channel dimensions. For another, the popular DeepLabv3+ in an encoder‐decoder architecture is useful in capturing multi‐scale contextual information and sharp object boundaries. The DAN‐DeepLabv3+ is applied to an available dataset containing 6666 images, where three types of steel defects are taken by high‐frequency cameras and have been annotated manually. Experimental results show that, compared with other deep learning models, DAN‐DeepLabv3+ based on the Xception backbone exhibits the best segmentation performance under the mean intersection over union (IoU) of 89.95% and the frequency‐weighted IoU of 97.34%. Besides, the F1‐score for the three kinds of defects can reach 86.90%, 99.20%, and 92.81%. From the comparative study, it has been found that the adoption of the dual attention module and DeepLabv3+ contributes to boosting the segmentation performance. The significance of the proposed hybrid model lies in the enhancement in accurately detecting single or multiple steel defects, which has proven to outperform other classical methods.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Batch and semi-continuous experiments were carried out to determine the effect of pH on hydrolysis and acidogenesis of kitchen wastes in the two-phase anaerobic digestion. The results of the batch ...experiment showed pH adjustment could improve both hydrolysis and acidogenesis rates of kitchen wastes. Compared with pH at 5, 9 and 11, pH 7 provided an optimum working condition for anaerobic digestion of kitchen wastes. At pH 7, about 86% of the total organic carbon (TOC) and 82% of chemical oxygen demand (COD) were solubilized and the maximum volatile fatty acid (VFA) concentration of 36g l
−1
was achieved on the fourth day. The total VFA yield was 0.27 g (g total solid (TS))
−1
, which almost doubled the yield without pH adjustment (0.15 g (g TS)
−1
). The acidified products with lower concentration of lactic acid were more favorable to the subsequent methanogenesis. At pH 7, most of the protein was degraded into ammonia nitrogen (NH
4
+
-N), resulting in additional buffer of acidified liquid. According to this, a novel method of pH adjustment applying NH
4
+
-N buffer was established. The semi-continuous experiment indicated that adjusting pH to 7 in the acidogenic stage in the two-phase anaerobic digestion process would increase both TS loading rate (16g l
−1
d
−1
) and recovery of biological energy (520 ml methane (CH
4
) (g TS)
−1
).
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
This paper investigates the effect of in-plane forces on the vibration behavior of carbon nanotube (CNT) reinforced composite skew plates. The analysis is performed by implementing the first-order ...shear deformation theory (FSDT) with the element-free/mesh-free Improved Moving Least Square-Ritz (IMLS-Ritz) method for solution to the problem. Two varieties of carbon nanotube-reinforced composite skew plates, namely uniformly distributed and functionally graded reinforcement are considered. A micromechanical model is employed to estimate the material properties of CNT-reinforced composite plates. Comparison studies are implemented to validate the accuracy of the proposed method. The frequency parameters and mode shapes for the skew plates are presented. A detailed parametric study is carried out to reveal many complicated effect on the frequency parameters of the plate. These effects include in-plane stress ratio, boundary conditions, CNT-volume fraction and geometric size. The obtained results will be references of future research and corresponding engineering project.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Iron oxide compounds constitute an important component of mineral dust aerosols. Several previous studies have shown that these minerals are strong absorbers at visible wavelengths and thus that they ...play a critical role in the overall climate perturbation caused by dust aerosols. When compiling a database of complex refractive indices of possible mineral species of iron oxides to study their optical properties, we found that uniformly continuous optical constants for a single type of iron oxide in the wavelength range between 0.2 and 50 μm are very scarce, and that the use of hematite to represent all molecular or mineral iron-oxides types is a popular hypothesis. However, the crucial problem is that three continuous data sets for complex refractive indices of hematite are employed in climate models, but there are significant differences between them. Thus, the real role of iron oxides in the optical properties of dust aerosols becomes a key scientific question, and we address this problem by considering different refractive indices, size distributions and more logical weight fractions and mixing states of hematite. Based on the microscopic observations, a semi-external mixture that employs an external mixture between Fe aggregates and other minerals and partly internal mixing between iron oxides and aluminosilicate particles is advised as the optimal approximation. The simulations demonstrate that hematite with a spectral refractive index from Longtin et al. (1988) shows approximately equal absorbing capacity to the mineral illite over the whole wavelength region from 0.55 to 2.5 μm, and only enhances the optical absorption of aerosol mixture at λ < 0.55 μm. Using the data set from Querry (1985) may overestimate the optical absorption of hematite at both visible and near-infrared wavelengths. More laboratory measurements of the refractive index of iron oxides, especially for hematite and goethite in the visible spectrum, should therefore be taken into account when assessing the effect of mineral dust on climate forcing.
Both inflammatory processes and glutamatergic systems have been implicated in the pathophysiology of mood-related disorders. However, the role of caspase-1, a classic inflammatory caspase, in ...behavioral responses to chronic stress remains largely unknown. To address this issue, we examined the effects and underlying mechanisms of caspase-1 on preclinical murine models of depression. We found that loss of caspase-1 expression in Caspase-1
knockout mice alleviated chronic stress-induced depression-like behaviors, whereas overexpression of caspase-1 in the hippocampus of wild-type (WT) mice was sufficient to induce depression- and anxiety-like behaviors. Furthermore, chronic stress reduced glutamatergic neurotransmission and decreased surface expression of glutamate receptors in hippocampal pyramidal neurons of WT mice, but not Caspase-1
mice. Importantly, pharmacological inhibition of caspase-1-interleukin-1β (IL-1β) signaling pathway prevented the depression-like behaviors and the decrease in surface expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) in stressed WT mice. Finally, the effects of chronic stress on both depression- and anxiety-like behaviors can be mimicked by exogenous intracerebroventricular (i.c.v.) administration of IL-1β in both WT and Caspase-1
mice. Taken together, our findings demonstrate that an increase in the caspase-1/IL-1β axis facilitates AMPAR internalization in the hippocampus, which dysregulates glutamatergic synaptic transmission, eventually resulting in depression-like behaviors. These results may represent an endophenotype for chronic stress-induced depression.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
► Effects of LSP on mechanical properties of stainless steel ANSI 304 are evaluated. ► LSP can clearly enhance the values of mechanical properties in the shocked region. ► Martensite transformation ...does not take place in the surface layer subjected to LSP. ► Enhancement mechanisms of LSP on mechanical property of stainless steel are revealed. ► The results can provide some insights on the surface modification of stainless steel.
The aim of this article is to address the effects of a single laser shock processing (LSP) impact on the nano-hardness, elastic modulus, residual stress and phase transformation of ANSI 304 austenitic stainless steel. Residual stress distribution of the LSP-shocked region is determined by X-ray diffraction (XRD) with sin
2
ψ method, and the micro-structural features in the near-surface layer are characterized by using cross-sectional optical microscopy (OM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). By comparing with the untreated samples, LSP can clearly improve nano-hardness, elastic modulus, and residual stress in the LSP-shocked region. The underlying enhancement mechanisms of LSP on nano-hardness, elastic modulus and residual stress of stainless steel ANSI 304 are also revealed. These studies may provide some important insights into surface modification for metal materials.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We report an efficient inkjet printing of water-based pristine GNPs graphene ink and a facile aqueous halogen doping process that provides significant and thermally stable conductivity enhancement of ...printed patterns. Highly concentrated aqueous graphene ink populated by few-layer pristine graphene flakes is obtained by means of scalable shear exfoliation process with the aid of bromine intercalation. The as-printed GNP films which has been merely treated by drying at 100 °C exhibits DC conductivity (σDC) of ∼1400 S/m likely due to bromine doping effect. This value is significantly increased to ∼3 × 104 S/m when an additional treatment by means of dipping in aqueous iodine solution is applied prior to the drying. As contrast, σDC is increased to ∼2.4 × 104 S/m when a mere annealing at elevated temperature in air is employed. When the aqueous iodine doping process and annealing at elevated temperature is combined, an unprecedented value of σDC ∼105 S/m is achieved. The availability of water-based GNPs inks and low-temperature doping scheme for efficient and reliable conductivity enhancement has offered a pathway for the application of GNPs in different printed electronics devices.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract
We report the X-ray timing results of the black hole candidate MAXI J1820+070 during its 2018 outburst using the Hard X-ray Modulation Telescope (Insight-HXMT) and Neutron Star Interior ...Composition Explorer Mission (NICER) observations. Low-frequency quasi-periodic oscillations (LFQPOs) are detected in the low/hard state and the hard intermediate state, which lasted for ∼90 days. Thanks to the large effective area of Insight-HXMT at high energies and NICER at low energies, we are able to present the energy dependence of the LFQPO characteristics and phase lags from 0.2 to 200 keV, which has never been explored by previous missions. We find that the centroid frequency of the LFQPOs does not change significantly with energy, while the full width at half maximum and fractional rms show a complex evolution with energy. The LFQPO phase lags at high energies and low energies show consistent energy-dependence relations taking the ∼2 keV as reference. Our results suggest that the LFQPOs from high energy come from the LT precession of the relativistic jet, while the low-energy radiation is mainly from the perpendicular innermost regions of the accretion disk.
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