Search

• For the first time, first-principles calculations are used to predict the lattice thermal conductivity of free-standing monolayer XS2 (X = mo and W) and monolayer XS2 supported on SiC (0001) and ZnO (0001) substrates. • The lattice thermal conductivity of monolayer XS2 supported on SiC (0001) and ZnO (0001) substrates show a significant decrease, and the decrease is even greater for the monolayer XS2 supported on ZnO (0001) substrates, reaching about 65–70 %. • The substrate drives softening of the acoustic branch, making the low-frequency phonon group velocity decrease and the three-phonon scattering enhance. • From the perspective of atomic bonding, the substrate breaks the symmetry of bonding of monolayer XS2, which leads to the increase of phonon anharmonicity and ultimately to a decrease in thermal conductivity of monolayer XS2. Thermoelectric materials have properties such as direct conversion of waste heat into electricity and environmental friendliness, which make them promising for renewable energy utilization, however, the lower conversion efficiency limits the large-scale application of thermoelectric materials. Monolayer transition metal dichalcogenides (TMDs) are candidates for thermoelectric materials due to their high power factor, but their higher thermal conductivity (TC) limits the further improvement of the figure of merit (ZT). Here, we employ first-principles calculations and solve the Boltzmann transport equation (BTE) to compare the lattice TC of free-standing monolayer XS 2 (X = Mo and W) and monolayer XS 2 supported on SiC (0001) and ZnO (0001) substrates. We find that the lattice TC of monolayer XS 2 supported on SiC (0001) and ZnO (0001) substrates are sharply reduced. Especially supported on the ZnO (0001) substrate, the lattice TC of XS 2 reduce by 65 %–70 %, which is expected to improve the thermoelectric properties of monolayer XS 2. In addition, we report the underlying cause of this significant reduction in TC. Firstly, the substrate drives softening of the acoustic branch, which leads to a decrease of phonon group velocity in the low-frequency and an enhancement of the three-phonon scattering. Then, the asymmetric bonding of XS 2 is induced by the substrates, which enhance phonon anharmonicity and reduce the phonon lifetime. Our results demonstrate that the lattice TC of monolayer XS 2 can be tuned by adjusting the substrate, which has certain reference values for the thermoelectric design of XS 2. SiC (0001) and ZnO (0001) substrates break the symmetry of the monolayer XS 2 (X = Mo and W) bonding, resulting in an increase in phonon anharmonicity, which reduces the contribution of the low-frequency acoustic branch of monolayer XS 2 to the thermal conductivity. [Display omitted] [ABSTRACT FROM AUTHOR]

Extreme heat events prolong the reproductive period and threaten soybean yield, whereas the specific stage at which individual fruits growth is delayed, and yield/yield components at the node, region, and plant levels under short-term heat stress in the reproductive stage are elusive. In this study, heat treatments (40/30 °C) were applied at 0–6 days (HT F0-6), 6–12 days (HT F6-12), 12–18 days (HT F12-18), and 0–12 days (HT F0-12) after the plant's first flower opened, and a control treatment (32/22 °C) was performed. The influences of heat stress on fruit development and yield/yield components at the node, region, and plant levels were investigated. As a result, the growth of individual fruits at nodes was delayed by HT F0-6 and HT F0-12 , which was primarily caused by the prolongation of flowering to pods with a length of 2 cm. Interestingly, there were no significant differences in yield between the control treatment and the various high-temperature stress treatments at the plant level. Further analysis of the regional yield of soybean showed that the yield in the bottom and top regions of plants played significant roles in compensating for yield loss in the middle region after HT F0-12. Moreover, the delayed growth of individual fruits in the middle region was negatively correlated with yield. Our results indicate that the prolongation of fruit development induced by HT F0-6 and HT F0-12 may adversely affect soybean yield. However, the spatial compensation of plants could help maintain soybean yield under various short-term high temperature stress treatments during the reproductive period, which should be considered when breeding for and selecting heat-tolerant varieties. [ABSTRACT FROM AUTHOR]

• Heterogeneous components are uniformly embedded into laser-induced graphene (LIG). • Shape-controllable MoS 2 /LIG electrodes are assembled into flexible in-plane MSCs. • Flexible planar MSCs are fabricated on various substrates to expand the application. • Flexible planar MoS 2 /LIG-MSCs exhibit high area specific capacitance. • MoS 2 /LIG-MSCs maintain excellent electrochemical performance at bending states. [Display omitted] As an essential miniature energy storage device, flexible in-plane micro-supercapacitors (MSCs) have the advantages of rapid charge and discharge, instantaneously high power output, long cycle stability and easy integration. However, the synthesis of electrode materials, the preparation of patterned microelectrodes and the subsequent modular integration are usually carried out independently, and the steps are very complicated. Accordingly, an effective and fast fabrication process involving laser direct writing technique is introduced to prepare shape-controllable MoS 2 nanoparticle-embedded laser-induced graphene (MoS 2 /LIG) patterned electrodes on various substrates for flexible planar MSCs. The embedding of MoS 2 nanoparticles can effectively improve the hydrophobic properties of MoS 2 /LIG hybrid electrodes, which is more conducive to the adsorption and desorption of aqueous electrolyte ions. Benefiting from the engineering of pseudocapacitive MoS 2 nanoparticles uniformly embedded in good conductive LIG with 3D porous structure, our flexible planar MoS 2 /LIG MSC demonstrates a superior areal capacitance of 35.3 mF cm–2, a high energy density of 4.91 mW h cm–2 at a power density of 0.18 mW cm–2, good cycle stability, outstanding mechanical flexibility, and prominent modular integration. The universal process route developed in this work can be used for controllable assembly of many similar flexible planar integrated MSCs, and may accelerate their potential application in flexible and wearable electronics. [ABSTRACT FROM AUTHOR]

Magnetite (MFe 2 O 4 , M = Mn, Zn, Ni, Co) nanosheet coated flaky FeSiAl alloy composite powder have been successfully synthesized. The morphology, composition, crystal structures, magnetism and electromagnetic performance of composite powder were studied systematically. Spinel ferrite nanosheet were prepared on the surface of flaky FeSiAl by hydroxide deposition decomposition. This structure will benefit the microwave multiple reflection loss. The saturation magnetization of the composite powder decreased with ferrite coating. The ZnFe 2 O 4 coated composite exhibited higher saturation magnetization while the CoFe 2 O 4 coated composite had the highest coercivity. Owing to the oxide coating, the complex permittivity and dielectric loss of the composite powder were evidently increased while the magnetic loss significantly decreased. Magnetic loss was dominant under 13 GHz and dielectric loss contributed equally as magnetic loss at higher frequency. Therefore, the composite powder attenuate the electromagnetic waves much more efficiently at higher frequency. Our results provide a reference to understand the effect of ferrite nanosheet coating on the magnetism and design the microwave absorption of composite powder materials. [Display omitted] • Magnetite (MFe 2 O 4 , M = Mn, Zn, Ni, Co) nanosheet coated flaky FeSiAl alloy composites have been successfully synthesized. • The flaky FeSiAl@ZnFe 2 O 4 composite exhibited higher saturation magnetization where FeSiAl@CoFe 2 O 4 composite has the highest coercivity. • High frequency attenuation capability is enhanced by loading ferrite. [ABSTRACT FROM AUTHOR]

Natural anthocyanins are safer and nutritious as compared to synthetic pigments; however, their stability is poor. They can produce spontaneous copigmentation with organic acids, leading to the improvement of colour stability, albeit slowly. Box–Behnken experimental design was used to elucidate the mechanism of copigmentation between Vitis amurensis Rupr anthocyanins (0.1 mg/mL) and organic acids (0.87 mg/mL, ferulic acid: d -gluconic acid:caffeic acid:vanillic acid = 1.5:2.5:2.5:0.5, w/w/w/w) promoted by high hydrostatic pressure (HHP; 300 MPa, 2 min). The copigmentation effect and antioxidant activity of anthocyanins were also evaluated. The structure of anthocyanins was analysed using ultraviolet–visible spectroscopy, Fourier-transform infrared spectroscopy, high-performance liquid chromatography, and mass spectrometry. The results of HHP copigmentation showed that the following anthocyanins were newly formed—delphinidin-3- O -catechol, petunidin-3- O -catechol, delphinidin-4-vinyl-catechol, petunidin-3- O -guaiacol, malvidin-4-vinyl-guaiacol, cyanidin-3- O -(6″- O -caffeoyl)-glucoside, peonidin-3- O -(6″- O -caffeoyl)-glucoside, delphinidin-3- O -(6″- O -caffeoyl)-glucoside, malvidin-3- O -glucoside-4-vinyl-guaiacol, and malvidin-3- O -(6″- O -feruloyl)-glucoside—owing to appropriate modifications that increased the copigmentation rate (R = 42.12%), photo-thermal stability (R > 45%), and potential antioxidant activities expressed in vivo ( p  < 0.01 vs. Model Group). [ABSTRACT FROM AUTHOR]

[Display omitted] • The main source of wine aroma and the formation mechanism are discussed. • The main influencing factors of aroma formation are analyzed. • The production and control of aroma in the winemaking process are concluded. As an important sensory indicator, aroma affects the quality of wine and consumer preference. In this review, the following aspects are comprehensively analyzed: (1) Varietal aroma, fermentation aroma and aging aroma formation mechanism include metabolic pathways etc. (2) The main factors affecting the aroma formation include environment, raw and auxiliary materials and brewing process. (3) In the process of winemaking, environmental factors can be controlled by regulating deficit irrigation, leaf removal and reflective mulch; the quality of raw and auxiliary materials can also be controlled through the varieties breeding of grape and yeast; flash evaporation, ultrasonic aging and other advanced brewing technologies can be used to synergistically control aroma formation. In the future, the wine brewing process can be controlled from the following aspects to ensure the precise regulation of aroma. This research will provide a theoretical basis for the improvement of wine production technology and quality. [ABSTRACT FROM AUTHOR]