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Magnetocaloric properties of TbCrO3 and TmCrO3 are reported and compared with those of the previously reported rare-earth chromites RCrO3 (R = Gd, Dy, Ho, and Er) and other perovskite-type oxides. The samples of TbCrO3 and TmCrO3 in this work were synthesized using a citrate gel combustion technique, and their magnetic properties were investigated and compared with those reported previously on RCrO3 (R = Gd, Dy, Ho, and Er). The Cr3+–Cr3+ ordering temperatures were found to strongly depend on the ionic radii of the rare-earth. By fitting the dc magnetization data with modified Curie–Weiss law including the Dzyaloshinsky–Moriya antisymmetric exchange interaction (D) and the symmetric exchange constant Je, spin canting angles (α) were obtained. In general, α was found to increase with the decreasing ionic radii of R3+ in RCrO3. The magnetocaloric properties investigated included the magnetic entropy change (−ΔS) for a given change in magnetic field (ΔH), the corresponding adiabatic temperature change (ΔTad), and their relative variations (ΔTad/ΔH) and (−ΔS/ΔH). It is observed that for RCrO3, (−ΔS) measured in the vicinity of the ordering temperature of R3+–R3+, varies almost as G2/3 where G is the de Gennes factor. Among RCrO3, GdCrO3 shows the largest value of (−ΔS/ΔH), because of its largest G factor and its magnitudes of (ΔTad/ΔH) and (−ΔS/ΔH) compare well with the reported values for the perovskites GdFeO3 and EuTiO3. These comparisons presented here provide useful information on the potential use of these materials in magneto-refrigeration technology. [ABSTRACT FROM AUTHOR]

In order to acknowledge the enrichment mechanism of organic matter in the black shale of the Middle Ordovician Yanxi Formation in central and southern Hunan area, the shale samples of the Yanxi Formation in the Maduqiao, Jinweixiang, Hejiadong and Mianhuaping are selected to test abundance of organic matter, major, trace and rare earth elements. The results show that the average total organic carbon (TOC) of black shale in study area is 2.03%, indicating the high abundance of organic matter in the Yanxi Formation. The CIA values and w(Sr)/w(Cu) ratios show that the Yanxi Formation had a warm and humid climate. The concentrations of Zn, V, Ni and Cu imply a medium primary productivity in the Yanxi Formation, whereas they have weak correlations with TOC. The element concentrations of V, Cr, Ni, and Mo reveal that the black shales were deposited in anoxic-euxinic conditions. The accumulation of organic matter is jointly affected by paleoclimate, primary productivity, redox conditions, sea level change and terrigenous debris. The organic matter enrichment model of the Yanxi Formation shales is a 'deepwater retention basin' controlleded by anoxic conditions. [ABSTRACT FROM AUTHOR]

The preparation of cement-based supplementary cementitious materials is an important method for the efficient use of iron tailings and the reduction in CO2 emissions. The aim of this study is to improve the reactivity of iron tailings by mixing them with steel slag, slag, and fly ash through orthogonal tests to solve the problem that iron tailings cannot be utilised on a large scale. The compressive strength, hydration products, and microstructure of the iron tailings–cement-based supplementary cementitious materials were investigated using ICP-OES, XRD, TG, FTIR, and SEM. The results revealed that each solid waste raw material played a distinct role in the hydration reaction. In the iron tailings–cement-based supplementary cementitious materials system, steel slag provided Ca2+, OH−, and Si4+ ions, slag provided Ca2+ and Al3+ ions, fly ash contributed a significant amount of Ca2+ and Al3+ ions, and iron tailings offered more nucleation sites and some Si4+ ions for the hydration products. Moreover, there was a synergistic effect among these four materials, promoting the formation of hydration products such as ettringite, C-(A)-S-H gels, and others. When the proportion of IOTs:SS:FA:SL was 9:8:8:2, the highest 7 d compressive strength of cementitious material was 24.8 MPa. When the proportion of IOTs:SS:FA:SL was 9:6:8:4, the highest 28 d compressive strength of cementitious material was 35.0 MPa. This study provides a comprehensive solution for the utilisation of iron tailings and contributes to the high-value green utilisation of solid waste. [ABSTRACT FROM AUTHOR]

The preparation of iron ore tailings (IOTs) into supplementary cementitious materials (SCMs) is an effective approach to achieve value-added utilization of industrial solid waste. This study systematically investigates the hydration pattern and strength development of Portland cement systems with the incorporation of IOTs, steel slag (SS), granulated blast-furnace slag (GBFS), and fly ash (FA) under the action of different chemical additives. The hydration products, and microstructure and pore structure of the SCMs are analyzed using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and mercury intrusion porosimetry. The findings of this study demonstrate that chemical activation plays a significant role in the strength development of SCMs. Among the five chemical activators tested, Triethanolamine (TEA) had the greatest influence on mechanical properties. The maximum compressive strength of the SCMs at 28 days was 42.9 MPa at a dosage of 1%. Specifically, the addition of TEA promotes volcanic ash reactions, and the high fineness of SCM provides nucleation sites for hydration products. Interactions between the volcanic ash reaction and the complexation reaction of TEA have a positive effect on compressive strength development. This research expands the potential for IOTs SCMs through chemical activation methods for value-added applications. [ABSTRACT FROM AUTHOR]

GaN's outstanding physical characteristics allow for a wide range of applications in numerous industries. Although individual GaN‐based ultraviolet (UV) photodetectors are the subject of in‐depth research in recent decades, the demand for photodetectors array is rising as a result of advances in optoelectronic integration technology. However, as a prerequisite for constructing GaN‐based photodetectors array, large‐area, patterned synthesis of GaN thin films remains a certain challenge. This work presents a facile technique for pattern growing high‐quality GaN thin films for the assembly of an array of high‐performance UV photodetectors. This technique uses UV lithography, which is not only very compatible with common semiconductor manufacturing techniques, but also enables precise patterning modification. A typical detector has impressive photo‐response performance under 365 nm irradiation, with an extremely low dark current of 40 pA, a high Ilight/Idark ratio over 105, a high responsivity of 4.23 AW−1, and a decent specific detectivity of 1.76 × 1012 Jones. Additional optoelectronic studies demonstrate the strong homogeneity and repeatability of the photodetectors array, enabling it to serve as a reliable UV image sensor with enough spatial resolution. These outcomes highlight the proposed patterning technique's enormous potential. [ABSTRACT FROM AUTHOR]

This article focuses on summarizing and analyzing the causes of errors in electric energy meters under harmonic conditions, clarifying the relationship between errors and frequency characteristic curves, and pointing out that the positive and negative errors mainly depend on the direction of each harmonic power relative to the fundamental power, the properties of the load, the differences in physical properties of electric energy meter manufacturing and material formation, etc. [ABSTRACT FROM AUTHOR]

The evaluation of geochemical properties of source rocks can provide an important basis for the accurate evaluation of hydrocarbon resources. In this paper, taking the Tanhai area of the Damintun Sag of Liaohe Oilfield as an example, the chemical properties of source rocks of the Dongying and Shahejie Formations of Paleogene are compared using a large number of geochemical and hydrocarbon generation thermal simulation results. The results show that the organic carbon content of the Dongying and Shahejie Formations in the study area ranges from 0.4% to 3.2%. It is considered that the source rock of the She 3 Member in Paleogene is good source rock. The Dong 3 and Sha 1 Members are the relatively good source rocks. While the Dong 2 Member is a relatively poor source rock, and the Dong 1 Member is the non-source rock. The vitrinite reflectance of Paleogene mudstone in the study area ranges from 0.33 to 0.93%, with an average value of 0.57%, which belongs to the immature to mature stage. Considering that the organic matter types in this area are mainly type IIB–III, the oil generation threshold is set at 2850 m. It is particularly noteworthy that thick coal measure strata are developed in the lower part of the Dong 3 Member and the upper part of the Sha 3 Member, although they are of poor type as oil source rocks, however, they are of great potential value as gas source rocks. The Shahejie source rock has the closest affinity with crude oil. Natural gas in the study area is mainly wet gas and a small amount is dry gas. The ratio of isobutane to n-butane (iC4 /nC4) in natural gas increased with decreasing depth, showing a certain migration differentiation effect. It is speculated that the Shahejie Formation source rock is the main source of natural gas in the Taiyangdao – Kuihuadao Structure. [ABSTRACT FROM AUTHOR]

The comparative study of dynamic and static rock mechanical properties of tight sandstone is of great significance to deepen the understanding of deep tight gas sandstone geological structure and improve the efficiency of oil and gas development. In this paper, taking the tight gas sandstone of the Sulige Gas Field as an example, experimental research on the difference of dynamic and static elastic parameters under different temperature and pressure conditions was carried out. Furthermore, the mechanism causing the difference of dynamic and static elastic parameters under different measurement conditions is analyzed. The results show that the dynamic Young's modulus measured under reservoir conditions is greater than the static Young's modulus, and there is a good linear correlation between the dynamic and static Young's modulus of rock samples. But the correlation between dynamic and static Poisson's ratio is relatively poor. The existence of microfractures has great influence on the static deformation of rock. It is also found that the dynamic Poisson's ratio of rock decreases with the increase of pressure and temperature. The longitudinal and transverse velocity changes of rock under reservoir conditions are the result of confining pressure and temperature combined in the experiment. In the process of dynamic splitting and crushing of sandstone, the strain rate increases with the increase of impact pressure. The rock has certain rebound effect during unloading. The stress time history curve of sandstone samples is related to the change of impact loading rate and the fracture failure mode. In addition, the accurate evaluation of rock mechanics parameters has a significant impact on fracture prediction. [ABSTRACT FROM AUTHOR]

Ultra-broadband high-performance photodetectors (PDs) are promising for diverse applications such as communication, imaging, environmental monitoring, and sensing. However, many PDs currently face issues of slow response speed, low sensitivity, poor air stability, and high energy consumption. In this work, we demonstrate a self-powered, broadband, and polarization-sensitive PD based on a ternary transition metal chalcogenide Nb2Pd3Se8 single crystal. The generation mechanism of photocurrent (PC) was confirmed by photoresponse measurements related to laser power and temperature. The Nb2Pd3Se8-based PD exhibits the maximum responsivity of 2.74 mA W−1 and a detectivity of 4.73 × 106 Jones with a 55–60 ms response time at 532 nm and high stability under ambient conditions over 6 months. Broadband detection capabilities from 365 nm to 10.6 μm are tested experimentally. Moreover, a strong polarization-sensitive PD with an anisotropic ratio of 1.42 is achieved. This work exhibits the enormous potential of Nb2Pd3Se8 for ultra-broadband, self-powered, polarization-sensitive, and air-stable PDs. [ABSTRACT FROM AUTHOR]

Rare earth chromites (RCrO3) continue to be of considerable interest due to their intriguing physical properties such as spin-reorientation, multiferroicity, and magnetocaloric effect. In this paper, we compare the structural, magnetic, and magnetocaloric properties of bulk ErCrO3 with those of bulk Er0.33Gd0.67CrO3, the latter obtained by Gd substitution at the A-site (Er-site) and report substantial enhancement in the magnetocaloric response by Gd substitution. The samples prepared by the citrate route were structurally characterized at room temperature using x-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy. The XRD measurements refined by Rietveld analysis indicate that both samples crystallized in the orthorhombically distorted perovskite structure with Pbnm space group. Magnetic measurements on both samples were carried out between 5 K and 300 K in magnetic fields up to 7 T and show that T N C r (where Cr3+ orders) for Er0.33Gd0.67CrO3 is enhanced to 155 K vs. 133 K for ErCrO3 with analogous changes in the other magnetic parameters. Isothermal magnetization M vs. H data at different temperatures were used to determine changes in the magnetic entropy ( − Δ S ) and relative cooling power (RCP) for the two samples showing considerable improvement with Gd substitution in bulk ErCrO3. The maximum value of − Δ S for Er0.33Gd0.67CrO3 is 27.6 J kg−1 K−1 at 5 K and 7 T with a RCP of 531.1 J kg−1, in comparison to maximum − Δ S = 10.7 J kg−1 K−1 at 15 K with an RCP of 416.4 J kg−1 for ErCrO3 at 7 T. [ABSTRACT FROM AUTHOR]

Broadband photodetectors with polarization-sensitive ability have received extraordinary attention for modern optoelectronic devices. Ideal photodetectors should possess high responsivity, fast response, and good stability, which are rare to meet at the same time in one low-symmetric two-dimentional (2D) material. In this work, neodymium diantimonides (NdSb2), a member of light rare-earth diantimonides RSb2 (R = La−Nd, Sm) with low-symmetry structure, is introduced as a fascinating highly anisotropic 2D material for broadband detection (532 nm to 4 µm). The photodetector exhibits a responsivity of 0.49 mA·W−1 with 15 µs response time at 532 nm and highly stable performance under ambient conditions over 8 months. Furthermore, we identify the polarization-sensitive photoresponse of the detector and demonstrate a high anisotropic factor ∼ 1.6. In addition, strong in-plane anisotropy is revealed by anisotropic phonon response and the photodetection mechanism is investigated by scanning photocurrent microscopy measurements. This pioneer work on NdSb2 paves the way for further exploration of 2D RSb2 for high performance polarized photodetectors with fast photothermoelectric response. [ABSTRACT FROM AUTHOR]

For patients who are suffering from liver dysfunction or metabolic obstruction, excessive bilirubin (BIL) in their bodies may cause jaundice with irreversible cerebral injury. Traditional exchange transfusion and photodynamic therapy pose a risk of serious adverse reactions or limited curative effects. Therefore, as a generally used treatment, hemoperfusion (HP) purifies patients' blood with solid adsorbents. However, the development of clinical BIL absorbents is greatly impeded by low selectivity and unsatisfactory blood compatibility. Herein, inspired by oviparity, we propose BIL-imprinted poly(acrylic acid-co-sodium p-styrenesulfonate)–reduced graphene oxide (PAA–SS–rGO@BIL) hydrogel beads as BIL adsorbents via self-sacrificing micro-reactors. In the micro-reactors, cross-linked polymerization is achieved and a solidified gel is formed. The received hydrogel beads show outstanding selective adsorption capabilities toward BIL due to the recognition sites, and π–π and hydrophobic interactions. Such hydrogel beads possess superior blood compatibility owing to their bioinspired heparin-mimicking gel structure. Simulated BIL selective adsorption experiments in vitro demonstrate that the BIL concentrations in the plasma of a patient with severe jaundice can be restored to a moderate level within 3 hours. Therefore, hydrogel beads offer new options for clinical BIL adsorption. [ABSTRACT FROM AUTHOR]

Polarized photodetectors have been widely used in military and civilian applications. The investigation of promising two-dimensional materials with low symmetry structures will be of great significance for the development of polarized integrated nanodevices. In this work, chromium thiophosphate (CrPS4), a ternary layered semiconductor with low symmetry puckered structures and unique linear dichroism (LD) conversion behavior is introduced to act as a polarization-sensitive photodetector. Angle-resolved polarized Raman spectra (ARPRS), polarization-resolved photoluminescence (PL) spectra, polarization-resolved absorption spectroscopy (PRAS), and electrical transport measurement systematically indicate intriguing anisotropic optical and electrical properties in 2D (two-dimensional) CrPS4. The photodetector of CrPS4 shows a linear anisotropy ratio of ≈1.33 with 405 nm illumination. This pioneering research not only stimulates interest in the development of novel anisotropic 2D materials but also enriches the family of polarization-sensitive photodetectors. [ABSTRACT FROM AUTHOR]

PdSe2, a star photosensitive functional material, has been successfully used in photodetectors based on sensing mechanisms of photogating, photoconductive, and photovoltaic effects. Here, a photothermoelectric (PTE) effect is observed in photodetectors based on PdSe2 flakes grown by chemical vapor deposition. The unique photoresponse arises from an electron temperature gradient instead of electron–hole separation. Direct evidence of the PTE effect is confirmed by a nonlocal photoresponse under zero bias. Moreover, the PdSe2 photodetector shows high performance in terms of ultrafast response speed (4 µs), high air‐stability, broadband spectrum photodetection, reasonable responsivity, and anisotropic optical response. This study paves a new way for developing high‐performance photodetectors based on PdSe2 layered materials. [ABSTRACT FROM AUTHOR]

Recently emerged hemoperfusion absorbents, e.g. ion-exchange resin, activated carbon, and other porous materials, provide numerous novel possibilities to cure chronic liver failure (CLF) and renal failure (CRF). However, the limited adsorption performance and unsatisfactory blood compatibility significantly impede the development of the absorbents. Hence, designing safe and self-anticoagulant hemoperfusion absorbents with robust toxin clearance remains a considerable challenge. Here, brand new Kevlar-based composite gel beads for hemoperfusion are prepared by interface assembly based on π–π interaction. First, Kevlar nanofiber–graphene oxide (K–GO) beads are produced by liquid–liquid phase separation. Then, sodium p-styrenesulfonate (SS) is adsorbed onto the K–GO interface by π–π interaction and initiated to achieve the composite gel (K–GO/PSS) beads with an interfacial crosslinked structure. Such composite gel beads possess superior mechanical strength and self-anticoagulation capability, owing to the dual-network structure and heparin-mimicking gel structure, respectively. Furthermore, the K–GO/PSS beads show robust adsorption capacities for different kinds of toxins due to their strong charge and π–π interactions. A simulated hemoperfusion experiment in vitro demonstrates that the concentrations of the toxins in the blood can be restored to normal values within 30 minutes. In general, we envision that such composite gel beads will provide new strategies for future clinical CLF and CRF treatments. [ABSTRACT FROM AUTHOR]

Rare-earth chromites are a new type of magnetoelectric multiferroics. In this work, a Ho0.33Gd0.67CrO3 powder sample was synthesized via a citrate route, and the structural properties were characterized by X-ray diffraction, scanning electron microscopy, and the Raman technique. The UV-Visible optical absorbance spectra were also measured in the wavelength range of 200–800 nm. The valence state of Cr was found to be purely 3+ according to the X-ray photoelectron spectroscopy. The temperature-dependent dielectric constant and loss tangent data measured between the frequencies of 1 kHz and 1 MHz show no anomalies around the magnetic transition temperature of the material. The dc magnetization measurements show that the ordering temperature of Cr3+ ( T N C r ) is 155 K for Ho0.33Gd0.67CrO3, which is larger than 140 K for HoCrO3. The positive slope of the Arrott plots from 0 T to 7 T reveals that the antiferromagnetic-paramagnetic phase transition is second-order in nature. At a field of 7 T, the Ho0.33Gd0.67CrO3 sample showed a giant magnetocaloric entropy change, −ΔS, of ∼23.3 J/kg K at 5 K, and a refrigeration capacity of ∼481.2 J/kg, which are much higher than those of pure bulk HoCrO3. This renders this material prospective for magnetic refrigeration in the low temperature (<30 K) range. [ABSTRACT FROM AUTHOR]

Low-symmetry two-dimensional (2D) materials have exhibited novel anisotropic properties in optics, electronics, and mechanics. Such characteristics have opened up new avenues for fundamental research on nano-electronic devices. In-plane thermal conductivity plays a pivotal role in the electronic performance of devices. This article reports a systematic study of the in-plane anisotropic thermal conductivity of PdSe2 with a pentagonal, low-symmetry structure. An in-plane anisotropic ratio up to 1.42 was observed by the micro-Raman thermometry method. In the Raman scattering spectrum, we extracted a frequency shift from the A g 3 mode with the most sensitivity to temperature. The anisotropic thermal conductivity was deduced by analyzing the heat diffusion equations of suspended PdSe2 films. With the increase in thickness, the anisotropy ratio decreased gradually because the thermal conductivity in the x-direction increased faster than in the y-direction. The anisotropic thermal conductivity provides thermal management strategies for the next generation of nano-electronic devices based on PdSe2. [ABSTRACT FROM AUTHOR]