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Anti-Stokes/Stokes Raman peak intensity ratio was used to infer sample temperature, but the influence factors of system correction factors were not clear. Non-contact in-situ anti-Stokes/Stokes temperature calibration was carried out up to 1500 K based on six different samples under two excitation light sources (±50 K within 1000 K, ±100 K above 1000 K), and the system correction factor γ was systematically investigated. The results show that the correction factor γ of anti-Stokes/Stokes thermometry is affected by the wavelength of the excitation light source, Raman mode peak position, temperature measurement region and other factors. The anti-Stokes/Stokes thermometry was applied to the laser-heating diamond anvil cell (LHDAC) experiment to investigate the anharmonic effect of hBN under high temperature and high pressure. It is concluded that the strong anharmonic effect caused by phonon scattering at low pressure gradually changes into the predominance of localized molecular lattice thermal expansion at high pressure.

With the development of new power systems, large amounts of decentralised clean energy and flexible loads will be connected to the smart grid, making the topology of the distribution network even more complex. At the same time, the demand for efficient interaction of “source-network-load” also makes the distribution network topology change with time, which makes it more difficult to identify the distribution network topology. However, topology identification is the basic data for power system regulation and safe optimal operation. Considering the above problems and requirements, this paper investigates and proposes a novel method to identify the topology of a distribution network based on the collaboration of data from multiple measurement devices. Firstly, a method based on multi-source data time synchronization method of μPMU measurement data is proposed, and generate additional data based on linear extrapolation to expand the available data set. Then, a method of topology optimization model identification based on least square method is proposed. Finally, the proposed algorithm is simulated in an example of the IEEE 33 bus feeder system standard. The results show that the scheme is effective in identifying the topology of the distribution network and improves the accuracy compared to traditional methods.

Based on first-principles calculations and quantum transport simulations, we systematically investigate the possibility of using two-dimensional transition metal borides (MBenes) as electrodes for two-dimensional monolayer MoS2 via interfacial interactions, band bending, vertical Schottky barrier, tunneling probability, and lateral Schottky barrier. The weak interaction between the functionalized MBenes and MoS2 results in MoS2 retaining its original intrinsic properties while significantly reducing the Fermi level pinning effect; this, is perfectly consistent with the revised Schottky–Mott model after considering charge redistribution. Combined with band calculations and device local projection density of states, MoS2/TiBO, MoS2/TiBF, and MoS2/MoBO, either with the vertical hole Schottky barrier or the lateral hole Schottky barrier, are negative, forming p-type ohmic contacts. Our work provides theoretical guidance for constructing high-performance nanodevices and MoS2-based logic circuits for large-scale integrated circuits. We demonstrate the outstanding potential of MBenes as electrodes for nanodevices.

Soft robots have attracted increasing attention due to their excellent versatility and broad applications. In this article, we present a minimally designed soft crawling robot (SCR) capable of robust locomotion in unstructured pipes with various geometric/material properties and surface topology. In particular, the SCR can squeeze through narrow pipes smaller than its cross section and propel robustly in spiked pipes. The gait pattern and locomotion mechanism of this robot are experimentally investigated and analysed by the finite element analysis, revealing that the resultant forward frictional force is generated due to the asymmetric mechanical properties along the length direction of the robot. The proposed simple yet working SCR could inspire novel designs and applications of soft robots in unstructured narrow canals such as large intestines or industrial pipelines.

In this paper, the research on the flow-adjustable gas generator of the solid rocket ramjet engine is carried out, and the internal flow field of the gas generator during the actuation of the flow control valve is analyzed. The steady and unsteady constant value simulations of the gas generator's working process are carried out respectively, and the static and dynamic flow field distributions in the control valve of the solid jet engine are obtained. The negative regulation in the gas flow adjustment process of the solid-jet engine is reproduced, and the reason for this phenomenon is analyzed based on the simulation results.

High-pressure Raman scattering from hexagonal close-packed (HCP) metals Os and Re have been extended up to 200 GPa, and the pressure-dependent shear modulus C 44 has been deduced from the Raman-active mode E 2g , which is generated from the adjacent vibration of atoms in hexagonal planes, providing the valuable information about the elastic properties for HCP metals under high pressure. Combined with the available data of HCP metals from previous works, a further study indicates that the C 44 ′ / C 44 ratio would be close to a constant value, 0.01, with increasing atomic number of metals. The results obtained from high-pressure Raman scattering will allow us to probe the elastic anisotropy of the HCP metals at very high pressure.

We observed an isostructural phase transition in the solid nitrogen λ-N2 at approximately 50 GPa accompanied by anomalies in lattice parameters, atomic volume and Raman vibron modes. The anomalies are ascribed to a slight reorientation of the nitrogen molecules, which does not seem to affect the monoclinic symmetry (space group P21/c). Our ab initio calculations further confirm the phenomena, and suggest an optimized structure for the λ-N2 phase. In addition, a new high-pressure amorphous phase of η′-N2 was also discovered by a detailed investigation of the pressure-temperature phase diagram of nitrogen with the aim of probing the phase stability of λ-N2. Our result may provide helpful information about the crystallographic nature of dissociation transitions in diatomic molecular crystals (H2, O2, N2, etc).

In this work, a novel phase change energy storage wood (PCESW) was fabricated by impregnating solid-solid phase change materials (SSPCM) into delignified wood. The SSPCM was prepared by using polyethylene glycol (PEG) 1500 as the thermal energy storage ingredient, hexamethylene diisocyanate (HDI) as the cross-linking agent and castor oil (CO) as the skeleton material. The chemical composition and structure of SSPCM and PCESW were confirmed by fourier transform infrared spectroscopy (FTIR); the crystalline structure of PEG and SSPCM were tested by x-ray diffraction (XRD); the microstructure of PCESW was observed by scanning electron microscopy (SEM); thermal properties and durability of SSPCM and PCESW were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The results showed that: (1) the porosity of wood was improved obviously after delignification and SSPCM mainly distributed in wood vessels; (2) PCESW-15 exhibited superior temperature-regulating performance and thermal stability; (3) PCESW-15 presented outstanding shape stability and no liquid leakage occurred during the phase transition. The great thermal performance of PCESWs suggested that it can be used as energy-saving building materials for indoor temperature regulating.

The high-frequency edge of the first-order Raman mode of diamond reflects the stress state at the culet of anvil, and is often used for the pressure calibration in diamond anvil cell (DAC) experiments. Here we point out that the high-frequency edge of the diamond Raman phonon corresponds to the Brillouin zone (BZ) center Γ point as a function of pressure. The diamond Raman pressure gauge relies on the stability of crystal lattice of diamond under high stress. Upon the diamond anvil occurs failure under the uniaxial stress (197 GPa), the loss of intensity of the first-order Raman phonon and a stress-dependent broad Raman band centered at 600 cm−1 are observed, which is associated with a strain-induced local mode corresponding to the BZ edge phonon of the L 1 transverse acoustic phonon branch.

Thermal energy storage wood (TESW) was fabricated by using graphene aerogel encapsulated polyethylene glycol (PEG) as phase change material and wood as the matrix. The microstructure of TESW was investigated by scanning electron microscope (SEM), the thermal properties of TESW was determined by differential scanning calorimetry (DSC), thermal gravimetric analysis (TG) and laser flash diffusivity apparatus (LFA). The results showed that: (1) graphene aerogel (GA) encapsulated PEG composite was founded in the lumens of wood, there was no apparent interface between PEG and graphene aerogel; (2) the melting and freezing enthalpy of TESW were 11.81 and 27.91 J g−1, respectively. The melting and freezing point were 20 °C and 15 °C, respectively, which were suitable for human comfortable temperature; (3) incorporation of graphene aerogel improved the thermal conductivity of TESW apparently. Thermal conductivity of TESW was 0.374 W (m*K)−1, which increased about 274% compared to pure wood; (4) TG and hygroscopicity test indicated that the TESW had excellent thermal and dimensional stability. The TESW was suggested as energy conservation building material for indoor temperature regulating due to its comfortable phase change temperature and prior latent heat.