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Iron in refractory iron ore composed of 47.04% Fe, 0.39% Pb and 0.30% Zn was enriched through reduction roasting followed by magnetic separation in this work. The phase transformations occurring in iron ore during reduction roasting were investigated through XRD, VSM, and SEM-EDS. Results show reduction process of hematite follows Fe2O3 → Fe3O4 → FeO → Fe. The quartz in iron ore reacts with FeO to form fayalite. At elevated temperatures, fayalite decomposes into metallic iron and cristobalite solid solution. The reductively roasted product (RRP) with main phases of magnetite and metallic iron has higher magnetization intensity than that with main phases of wustite and fayalite. Iron in RRP-800 °C and RRP-1150 °C is extracted by magnetic separation, and obtained concentrates have main minerals of magnetite and metallic iron, respectively. Elevated temperature decreases zinc and lead contents in concentrate. Thus, deep reduction-magnetic separation is more suitable for enriching iron from Zn- and Pb-bearing refractory iron ore.

Friction stir processing (FSP) was used to modify the microstructure and improve the mechanical properties and corrosion resistance of an Mg–Al–Ca alloy. The results demonstrated that, after FSP, the grain size of the Mg–Al–Ca alloy was decreased from 13.3 to 6.7 μm. Meanwhile, the Al8Mn5 phase was broken and dispersed, and its amount was increased. The yield strength and ultimate tensile strength of the Mg–Al–Ca alloy were increased by 17.0% and 10.1%, respectively, due to the combination of fine grain, second phase, and orientation strengthening, while the elongation was slightly decreased. The immersion and electrochemical corrosion rates in 3.5 wt% NaCl solution decreased by 18.4% and 37.5%, respectively, which contributed to grain refinement. However, the stress corrosion cracking (SCC) resistance of the modified Mg–Al–Ca alloy decreased significantly, which was mainly due to the filiform corrosion induced by the Al8Mn5 phase. SCC was mainly controlled by anodic dissolution, while the cathodic hydrogen evolution accelerated the SCC process.

In this paper, a washing-machine-shaped experimental device is presented to investigate the effect of marine environments on the penetration of chlorides in concrete. The proposed experiment is used to simulate different flow speeds and wave patterns surrounding the concrete and examine their effects on the penetration of chlorides in the concrete. The obtained experimental results show that there is a significant difference in chloride profiles between the specimens exposed to a marine environment with flow and wave actions and those immersed in a stationary solution. The difference is found to increase with exposure time, suggesting the importance of considering the marine environment when predicting the long-term durability of concrete exposed in a marine environment.

The study on hydromechanical coupling properties of rocks is of great importance for rock engineering. It is closely related to the stability analysis of structures in rocks under seepage condition. In this study, a series of conventional triaxial tests under drained condition and hydrostatic compression tests under drained or undrained condition on sandstones were conducted. Moreover, complex cyclic loading and unloading tests were also carried out. Based on the experimental results, the following conclusions were obtained. For conventional triaxial tests, the elastic modulus, peak strength, crack initiation stress, and expansion stress increase with increased confining pressure. Pore pressure weakened the effect of the confining pressure under drained condition, which led to a decline in rock mechanical properties. It appeared that cohesion was more sensitive to pore pressure than to the internal friction angle. For complex loading and unloading cyclic tests, in deviatoric stress loading and unloading cycles, elastic modulus increased obviously in first loading stage and increased slowly in next stages. In confining pressure loading and unloading cycles, the Biot coefficient decreased first and then increased, which indicates that damage has a great impact on the Biot coefficient.

The output power of the pulsed power supply (PPS) pulsates at the pulse repetition frequency (PRF) of pulse load. The pulsating power will result in a large bus voltage ripple. To balance the instantaneous power difference, a single or dual-inductance active storage unit (ASU) is usually connected in parallel with the output terminal of the PPS. Poor compensating current tracking accuracy of ASU will lead to the output current of PPS suffered from serious current spikes, which affects the stability of the bus voltage. A hysteresis current control (HCC) is proposed to achieve an excellent pulse current compensation performance. Compared with the current mode control (CMC), the small-signal modeling of dual-inductance with HCC is established to illustrate good compensation performance. Besides, a valley voltage loop is introduced to regulate the storage capacitor voltage in dual-inductance ASU to reduce the power loss at any pulse duty cycle. An experimental prototype is built to verify the spikes in output current can be eliminated effectively, the bus voltage keeps smooth and stable, and the output capacitor of the per-stage DC/DC converter is reduced significantly.

Thin-walled tubular structures are widely employed in applications. The current study proposes an innovative cost-saving and eco-friendly thin-walled cylinder concept using recycled beverage cans. ...

Two coordination polymers, [M(5-hip)(H2O)3]n (M = Cd2+ (1), Zn2+ (2), 5-hip = 5-hydroxyisophthalic acid), have been synthesized under hydrothermal conditions. The crystal structure reveals that complexes 1 and 2 have 1D chain structures by the coordination of metal ions and 5-hip. 1D chains are connected by hydrogen bonds to form a 3D structure. AC impedance analysis shows that the proton conductivity of complexes 1 and 2 comes up to 1.58 × 10-3 S cm-1 (98%RH, 343 K) and 5.27 × 10-4 S cm-1 (98%RH, 353 K), respectively. To further improve the proton conductivity, a hybrid membrane was prepared by the solution casting method with complexes as fillers and sulfonated polyether ether ketone (SPEEK) as the organic matrix. The proton conductivity of hybrid membranes 1@SPEEK-5 and 2@SPEEK-5 is 1.97 and 1.58 times higher than that of pure SPEEK membranes, respectively. Furthermore, the two complexes are excellent fluorescent sensors, which could detect Cr2O72- in aqueous solution with high sensitivity and selectivity. Both of them have low detection limits for Cr2O72- in aqueous solution, where the detection limit of complex 1 is 0.8 μM and that of complex 2 is 1 μM. The above work demonstrates that the two complexes are dual-functional materials with high proton conduction and good fluorescence properties.

To explore the initial orientation effect of ballast assembly on the reinforcement performance of the geogrid reinforced ballast, particles with random orientation and five prescribed rotational orientations were developed through particle flow code (PFC3D). The evolution laws of the pullout force and the principal directions of the normal contact force were systematically compared and analyzed. Furthermore, the mechanical responses such as pullout force, distribution of axial force, displacement vectors, force chain, and mesoscopic fabric were discussed. According to the displacement vectors of the ballast particles, the average thickness of the stable shear band is determined. The inherent relationships among the force chain, the rotational angle of the normal contact force, and the mesoscopic fabric parameters are revealed. The results show that the pullout force of specimens with the initial orientation of 45° increases monotonously during the pullout process, and the peak value of pullout force appears at the end of the test. The mesostructural analysis also confirms that the evolution of the principal direction of contact normal force is relatively steady during the pullout process, indicating that the specimen with 45° orientation possesses higher systematic stability and ductility. Moreover, the optimum interval from 56.68° to 57.30° is observed to remain in a self-adapting state for ballast assembly.

Friction stir lap welding (FSLW) was employed to weld dissimilar joints of zirconium and stainless steel for the first time. The microstructure, evolution mechanism of intermetallic compounds (IMCs) and mechanical properties of joint were investigated. Discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) occurred in zirconium, while DDRX occurred in stainless steel during FSLW. The formation sequence of IMCs at the interface was FeZr3, FeZr2, Fe2Zr, and Fe23Zr6. The crack nucleated at the hook zone on the advancing side (HookAS), and IMCs in the Zr/SS mixed zone accelerated crack propagation. The fracture surface exhibited ductile-brittle mixed fracture characteristic.

With the development of high-voltage switches and high-speed RF circuits, the enhancement mode(E-mode) AlGaN/GaN HEMTs have become a hot topic in those fields. The E-mode GaN-based HEMTs have channel current at the positive gate voltage, greatly expanding the device in low power digital circuit applications. The main methods to realize E-mode AlGaN/GaN HEMT power devices are p-GaN gate technology, recessed gate structure, fluoride ion implantation technology and Cascode structure (Cascode). In this paper, the advantage and main realizable methods of E-mode AlGaN/GaN HEMT are briefly described. The research status and problems of E-mode AlGaN/GaN HEMT devices fabricated by p-GaN gate technology are summarized. The advances of p-GaN gate technology, and focuses on how these research results can improve the power characteristics and reliability of E-mode AlGaN/GaN HEMT by optimizing device structure and improving process technology, are discussed.

The authors have proposed a dual-band reconfigurable Fabry–Perot (F-P) cavity antenna with high gain and meanwhile small radar cross-sections (RCSs) in wideband. Different from the traditional F-P antennas, they used a dynamic metasurface reflective plane (DMRP) as the lower superstrate to realise reconfigurable functions and a digital coding metasurface as the upper superstrate to achieve wideband RCS reduction. To investigate the dual-band reconfigurability, a wideband rectangular waveguide is used to feed the F-P antenna. By varying the bias voltage applied to varactors embedded in the elements of DMRP, the reflection phase of DMRP is changed and the two operating frequencies can be tuned electronically. To realise RCS reduction, they adopted a meticulous arrangement of the coding elements on partially reflecting surface. The designed metasurface-assisted F-P antenna has good radiation performance with high gain, high aperture efficiency, and high radiation efficiency. In the experiments, a prototype was fabricated via printed circuit board technology, and measured results agree well with numerical simulations. The measured peak gain reaches 17.52 dBi and the maximum aperture efficiency is 56.97%. The two reconfigurable bandwidths cover 5.10–5.40 and 6.60–6.93 GHz, respectively; and 7 dB RCS reduction is achieved from 9.40 to 13.7 GHz for arbitrary polarisation

This work is mainly focused on developing a self-heating composite fabric using the PVF and PPP. Prepare a new functional composite self-heating fabric through core spun method based on the synergy...

Sandblasted, large-grit, and acid-etched (SLA) titanium (Ti) with microtopography is currently one of the most widely used implant materials to accelerate osseointegration. Numerous long noncoding RNAs (lncRNAs) have been involved in bone remodeling, with their role in osseointegration, and the underlying mechanisms remain largely unclear. Here, microarrays of human bone marrow mesenchymal stem cells (hBMSCs) were used to identify differentially expressed lncRNAs during early cell differentiation stages (0-7 days) on SLA Ti and polished Ti surfaces. The function of lncRNAs in the osteogenic differentiation of hBMSCs was identified by RNA silencing and overexpression assays. RT-PCR and Western blot were used to detect RNA and protein expression. Alkaline phosphatase (ALP) protein activity was tested by ALP staining. Altogether, 4112 differentially expressed lncRNAs were identified from day 0 to day 7 on SLA Ti with a novel lncRNA, Prader-willi region non-coding RNA 1-209 (PWRN1-209) upregulated. We then proved that PWRN1-209 promoted osteogenic differentiation in hBMSCs by genetic tools. The upregulation of PWRN1-209 was further confirmed to be related to the surface topography of Ti by comparing SLA Ti and polished Ti. Interestingly, this trend seems to have a certain correlation with the mRNA expression level of integrins (α2, αV, β1, β2) and the phosphorylation of focal adhesion kinase (FAK). Taken together, the lncRNA PWRN1-209 was upregulated by the SLA microtopography Ti surface, which may regulate osteogenic differentiation of hBMSCs through integrin-FAK-ALP signaling. Our results provide new insights into the relationship between surface topography and osseointergration.

A two-stage analysis of the support-rock interaction is carried out using a proposed numerical procedure. The procedure provides a simplified solution for readily obtaining the final support load a...

The behaviour of a granular material is primarily affected by its particle size distribution (PSD), which is not necessarily a soil constant as assumed in traditional soil mechanics. The PSD may change over time due to mechanical as well as environmental actions. In this study, a series of ring shear tests and one-dimensional compression tests were completed on carbonate sand, in both dry and saturated conditions. Samples were prepared with different initial uniform gradings, to investigate: (1) the influence of the saturation state and initial grading on mechanical and deformational behaviour of carbonate sands and (2) the evolution of the PSD as a result of breakage. The ring shear tests show that the residual friction angle remains almost constant, but dilatancy reduces with increasing saturation degree. In the one-dimensional compression test, the yield stress decreases with increasing saturation degree, but the compressibility (as defined by Cc) remains almost constant, irrespective of the saturation state. Moreover, saturated samples suffer more breakage than dry samples during ring shear tests, while there is no obvious effect of saturation state on particle breakage in one-dimensional compression. A recently proposed PSD model with only two parameters (λp and κp) is employed to model the evolution of PSD, as it can more broadly capture the whole PSD throughout the breakage process than existing breakage indices. Test results demonstrate that parameter λp is linearly related to Einav’s breakage index $$ B_{\text{r}}^{*} $$ and is dependent on initial grading, but independent of test mode. Parameter κp is in power relationship with $$ B_{\text{r}}^{*} $$ and is independent of initial grading or test mode. The evolution of parameters λp and κp is related to the input work for both ring shear and compression tests, with λp being hyperbolically related to input work and κp in power relationship with input work. Using such an evolution law provides an alternative approach to capture the effects of particle breakage in constitutive models.

Octahedral CdS–ZnS composites were synthesized using a simple method of cation exchange and hydrothermal treatment, using Cd3(C3N3S3)2 (denoted as Cd3(TMT)2) as a precursor and Zn2+ for ion exchang...

In this work, {[Zn(H2PIPZ)](H2O)}n was synthesized by self-assembly of an N,N′-piperazinebis(methylenephosphonic acid) [H4PIPZ] ligand and zinc chloride under hydrothermal conditions. The Zn2+ ion is four-coordinated by oxygen atoms from four different H2PIPZ2− ligands to form a tetrahedral configuration. The Zn2+ tetrahedral units are further connected by a phosphate group of the H2PIPZ2− ligand to form a 3D structure. AC analysis shows that the proton conductivity of compound 1 is excellent and by introducing 1 into PVA to make composite membranes, the proton conductivity of composite membrane 1@PVA-10 (10% wt) reached 2.78 × 10−4 S cm−1 at 98% RH and 353 K, which is approximately ten times higher than that of 1. In addition, compound 1 has excellent selectivity and sensitivity to cobalt ions in water due to turn on fluorescence. The detection limit is 1.0 × 10−8 M. In contrast, the Fe3+ ion has a turn off fluorescence effect on 1 and the detection limit is 1.0 × 10−6 M.

Toxoplasma Gondii is an obligate intracellular protozoan. T. gondii tachyzoites can invade nucleated host cells and inhibit their apoptosis. Therefore, the goal of the present study was to determine whether rhoptry protein 16 (ROP16) secreted by the invading T. gondii can reduce the apoptotic response of the host cell. For this purpose, a vector for in vitro overexpression of T. gondii ROP16 was constructed and used to transfect human 293T cells. Cells transfected with the vector robustly expressed ROP16, as evidenced by Western blotting. Apoptosis of 293T cells was induced by incubation with 0.5 μg/mL actinomycin D (ActD) for 24 h, and its magnitude was measured using Annexin V-FITC/PI and TUNEL assays. Cells transfected by ROP16-expressing vector were characterized by a significantly lower level of apoptosis measured by both techniques.Moreover, caspase-3 activity was also reduced. Thus, ROP16 inhibited ActD-induced apoptosis of human 293T cells, documenting the ability of this rhoptry protein to modulate apoptosis of host cells infected by T. gondii.

Particle breakage of carbonate sands is widely encountered during the construction of harbor facilities. In this study, a series of one-dimensional compression tests on carbonate sands with different initial particle size distributions (PSDs) and initial void ratios were completed at high vertical stress (32 MPa), to investigate the influence of PSD and void ratio on the compression behavior of carbonate sands and the corresponding breakage properties. The PSDs used in this study were prepared by fractal distribution with two different fractal dimensions, i.e., 0.5 and 2.0. The results show that samples with fractal dimension of 0.5, where the initial PSDs are poorly graded, have a unique normal compression line (NCL), implying the occurrence of non-transitional behavior. However, when the PSD of samples tend to be better graded with fractal dimension of 2.0, non-convergent compression paths are likely to occur, which means a transitional behavior is identified. Particle breakage is observed after compression tests on samples with two different initial PSDs. It can, therefore, be concluded that particle breakage may have happened in both transitional and non-transitional behavior soils.

Lithium–sulfur (Li–S) battery is identified as one of the most promising next‐generation energy storage systems due to its ultra‐high theoretical energy density up to 2600 Wh kg−1. However, Li metal anode suffers from dramatic volume change during cycling, continuous corrosion by polysulfide electrolyte, and dendrite formation, rendering limited cycling lifespan. Considering Li metal anode as a double‐edged sword that contributes to ultrahigh energy density as well as limited cycling lifespan, it is necessary to evaluate Li‐based alloy as anode materials to substitute Li metal for high‐performance Li–S batteries. In this contribution, the authors systematically evaluate the potential and feasibility of using Li metal or Li‐based alloys to construct Li–S batteries with an actual energy density of 500 Wh kg−1. A quantitative analysis method is proposed by evaluating the required amount of electrolyte for a targeted energy density. Based on a three‐level (ideal material level, practical electrode level, and pouch cell level) analysis, highly lithiated lithium–magnesium (Li–Mg) alloy is capable to achieve 500 Wh kg−1 Li–S batteries besides Li metal. Accordingly, research on Li–Mg and other Li‐based alloys are reviewed to inspire a promising pathway to realize high‐energy‐density and long‐cycling Li–S batteries.

A coordination polymer with dual functions of high proton conductivity and highly sensitive fluorescent sensors demonstrates a great application potential. In this work, a cadmium-based coordination polymer (denoted as CP 1) with hydrothermal stability was synthesized. The abundant coordination water, lattice water, and amino groups make an extended hydrogen-bonding pathway for efficient proton migration, which endows CP 1 with the highest proton conductivity of 2.41 × 10-3 S·cm-1 at 353 K and 98% RH. Especially, the proton conductivity of the chitosan (CS) hybrid membrane containing CP 1 reaches a maximum value of 2.62 × 10-2 S·cm-1 under 343 K and 98% RH, which increases almost 7 times higher than that of the pure CS membrane due to the host-guest collaboration. Furthermore, luminescence studies revealed that CP 1 is a high-sensitivity and good-selectivity fluorescent probe for the detection of trace amounts of l-histidine with a lowest detection limit of 1.0 × 10-8 M.

A prompt gamma neutron activation analysis (PGNAA) system based on a deuterium-deuterium (D-D) sealed neutron generator was designed using the MOCA code for explosive detection. The system is mainly composed of four parts: D-D sealed neutron generator, moderator, shielding, and Lutetium Yttrium OxyorthoSilicate (LYSO) scintillation detectors. Polyethylene (PE) was selected as the moderator and the optimal thickness was 7cm. Lead, PE, and boron-containing polyethylene were used as shielding materials. In the optimized model, the LYSO detector is used to measure eighteen materials, such as wood, melamine, glucose, and nylon, and so on. Firstly, the nitrogen characteristic peak of 10.8 MeV was analyzed to determine whether the material contained nitrogen. Then, the ratio of characteristic peak counts of C/O and O/N were calculated to distinguish explosives from nitrogen containing materials. Finally, dinitrobenzene, nitroglycerin, TNT, and ammonium nitrate can be separated from nitrogenous substances by a discriminant algorithm. The final device can be used to detect the chemical composition of the threat substances, and the maximum dose rate of the system meets the limits of international protection standards.

In order to deal with the great surface tension and difficulty on wetting the micro dust, this paper designs wetting experiment of surfactant and studied the influence of its concentration on the contact angle and reduction efficiency of coal dust. Based on the collision coupling mechanism between surfactant and coal dust, the contact angle between surfactant and coal powder is measured by drop angle method. An experimental platform for spray dust suppression is designed, and dust removal efficiency is calculated by adding surfactant in the water. The experimental results show that the wettability of surfactant to coal dust increases with the increase of its concentration. When the surfactant concentration reaches the critical micelle concentration, the solution has the best wettability to coal dust. The wettability of anionic surfactant solution to coal dust is stronger than that of nonionic surfactant solution and cationic surfactant solution; with the increasing surfactant concentration, the efficiency of air water spray and dust removal is the optimal when the surfactant concentration reaches critical micelle concentration.

A dual circulating fluidized bed reactor for chemical looping combustion of coal has the advantage of flexible regulation on oxygen carrier circulation, but there is always part of unconverted coal...

The photocatalytic conversion of CO2 to fuels by light is of research interest owing to its relevance to environment and energy concerns. In this work, a hybrid H-TiO2–rGO–Re(bpy)(CO)3Cl composite consisting of a rhenium 2,2′-bipyridine compound, Re(bpy)(CO)3Cl, which was covalently grafted on reduced graphene oxide (rGO) and hydrogenated TiO2 (H-TiO2) was prepared. H-TiO2–rGO–Re(bpy)(CO)3Cl demonstrated high efficiency for visible light photo-conversion of CO2 into CO in triethanolamine/N,N-dimethylformamide (V:V = 1:9) solution with total turnover numbers larger than 580. In addition, the composite showed high stability with no leveling-off tendency after four catalytic experimental runs. The experimental results indicate that the suitable assembly of the Re(bpy)(CO)3Cl, rGO, and H-TiO2 components in the H-TiO2–rGO–Re(bpy)(CO)3Cl composite is necessary for the observed high performance of the catalyst for CO2 reduction under visible light irradiation.

Localized surface plasmon resonance (LSPR) field enhancement effects of noble metallic nanoparticles can be exploited to enhance the performance of diverse luminescent materials and devices, in whi...

Prediction of the evolution of particle size distribution (PSD) is of great importance for studying particle breakage. This paper presents a stochastic approach, namely a Markov chain model, for predicting the evolution of PSD of granular materials during one-dimensional compression tests. The model requires the survival probability of each size group particles in an assembly, named as the survival probability matrix. The Weibull distribution is used to capture the particle size and particle strength effects of single particles. The evolution of the coordination number is investigated via 3D discrete element simulations. The proposed analytical form of survival probability matrix with consideration of the coupling effect of particle-scale factors (i.e., particle size, particle strength) and evolution of the coordination number during one-dimensional compression shows that the largest particles in an assembly do not always have the maximum breakage probability (or the minimum survival probability). This also confirms the dominant role of the coordination number on the balance of evolution of PSD within granular soils. The proposed model is validated against experimental data from one-dimensional compression tests on different granular materials. The limitations as well as possible future developments of the model are discussed.

In this study, we adopt laser-melting deposition (LMD) technology to fabricate TiB2/7075 aluminum matrix composites (AMCs), and we investigate in detail the effect of the TiB2 content on the microstructure, nano-hardness, compressive properties, and wear performance. We prepare experimental samples by using a laser power of 800 W and a velocity of 0.01 m/s, and the results are evaluated. It was observed that the reinforcement particles dispersed irregularly throughout the Al matrix as the TiB2 contents increased. The grain size of the fine-grain zone decreased appreciably by 31.9% from 8.41 µm (LMD sample without TiB2 reinforcement) to 5.73 µm. Furthermore, the AMCs with 4 wt% reinforcement exhibited impressive mechanical properties, i.e., nanohardness of 1.939 Gpa, compressive strength of 734.8 MPa, and a wear rate of 1.889 × 10−4 mm3/Nm. The wear resistance improved and the wear mechanism changed from adhesive wear to debris wear with the addition of TiB2 reinforcement.

In this study, a calibration model based on Near-infrared spectroscopy (NIR) technique and chemometrics method was developed for rapid and non-destructive detecting the polysaccharide contents of lentinula edodes samples collected from different regions. The polysaccharide contents of these samples were firstly determined by standard phenol-sulphruic acid method. Then, NIR spectra of these samples were collected by using Fourier transform infrared spectrometry. Based on these experimental data, a random forest method was further used to distinguish the regions of these samples, with a classification accuracy of 96.6%. After that, a rapid, accurate, and quantitative model was established for predicting the polysaccharide contents of these samples. In the model establishing process, some signal pre-treatment methods were optimized, and the validation results with highest determination coefficient (R2) and low root mean square errors of prediction (RMSEP) were, 0.925 and 0.720, respectively. These results showed that combined NIR technique with chemometrics was an effective and green method for lentinula edodes quality control.

Organic crystals simultaneously displaying high carrier mobility and high luminescence efficiency are expected to be of interest for the fundamental research of light-emitting devices, and may offer renewed hope for achieving electrical pumping of solid-state organic lasers. However, high charge transport and efficient light emission have been mutually exclusive due to the different inherent natures of their aggregation states in single crystals. Here, we report the successful growth of a pentacene-doped 1,4-bis(2-cyano styryl)benzene (2-CSB⊂Pc) crystal that showed a high carrier mobility of 0.51 cm2 V−1 s−1, efficient emission of red light with a quantum yield of up to 50%, and a low amplified spontaneous emission (ASE) threshold of 46 kW cm−2 using a physical vapor transport (PVT) method. The achieved high carrier mobility was due to the retention of structural order after doping Pc molecules into the 2-CSB matrix, as well as being due to the extensive intermolecular π-orbital overlap stacks in the crystal. The spectral matching between 2-CSB emission and Pc absorption promoted host–guest energy transfer leading to the high luminescence efficiency, and meanwhile, the uniaxially oriented molecular arrangement had the benefit of producing ASE with a low energy threshold. The molecular electronic structures, reorganization energies and orbital overlap integrals were calculated to further elucidate the influences of Pc doping on the luminescence and charge transport characteristics. The primary results indicated that integrated multi-functional optoelectronic crystals can be obtained via a doping strategy, which is of great significance for developing high-performance organic laser materials and devices.

In China, the production has not realized intensive cultivation and the problem of cadmium (Cd)-contaminated rice is salient, so it is important to classify rice with different degrees of Cd pollution by rapid detection method in situ. This paper established a method with a combination of dilute acid extraction pretreatment and electrochemical devices. Cd was extracted from rice using 3% HCl for 5 min. A standard curve was obtained based on a certified reference material in the rice matrix with different concentrations of Cd, which was fitted with the Cd concentration (μg kg−1) against the stripping peak current value (μA), and the linear correlation coefficient was 0.9997. To analyze the applicability of the method, three factors including substrate diluents, particle diameter of the sample, and stability towards the method were evaluated. The limit of detection (LOD) was 2.02 μg kg−1, and the repeatability and accuracy were satisfactory. Cd was determined in 142 samples collected from three major grain-producing provinces of China, and the results have good consistence with the microwave digestion-ICP-MS method. The developed method combined dilute acid extraction with a matrix matching standard curve in ASV for the first time, and it was significantly satisfactory for the detection requirements in China.

Rocket jet flow and airflow represent a typical mixing layer flow in a combustion chamber of a combined air-breathing propulsion system. Previous studies indicate that highly and weakly compressible mixing layers are similar in growth rate, turbulent intensity, and Reynolds stress. Flow Reynolds number was set to a range that a direct numerical simulation (DNS) can address. A high-order discretization DNS of a 3D spatially developing supersonic mixing layer flow was conducted, and detailed mixing layer flow structures were acquired. Results showed that the flow structure of a subsonic–supersonic mixing layer is similar to a supersonic–supersonic mixing layer. A shocklet structure can be observed in the mixing layer with a convective Mach number (Mc) of 0.69. However, the flow structure in the development region of the mixing layer becomes minimally ordered and lacks main frequency. Proper orthogonal decomposition (POD) analysis shows that a high POD mode has a relatively large proportion. In addition, the transition region of the subsonic–supersonic mixing layer has strong 3D flow characteristics.

Because of its ultra-high energy efficiency and low emissions, new energy vehicles have become the best technological way to achieve low carbon emissions and high efficiency in the automobile industry. But the permanent magnet synchronous in-wheel motor is directly installed in the wheel hub, so that its temperature rise is higher than other vehicle drive motors. In this paper, the permanent magnet synchronous in-wheel motor was simulated based on the thermal network method in Motor-CAD, the heating situation of the permanent magnet synchronous in-wheel motor was analysed, and the best cooling system was selected based on Taguchi method. Finally, the optimum scheme is determined as follows: the channel type is circumferential C-shape, the cooling medium is water, and the coolant flow rate is 14L/min.

Stress concentration will cause mechanical strength deterioration of three-post insulators in GIL, which may threaten the safe and stable operation of GIL. In this paper, the simulation model of a 550 kV GIL three-post insulator is established, and the stress and strain simulation of three post insulator under horizontal and vertical installation conditions are carried out. The stress and strain development laws of the insulator under different radial pressures and axial tensions are studied. The results show that the maximum radial pressure is 9197.1 N in horizontal installation and 2975.2 N in vertical installation. Regardless of the loading mode, the maximum stress of the insulator is at the interface between the epoxy and the grounding insert. With the in-crease of load, the maximum stress and strain of the three-post insulator increase linearly.