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Solar-driven water vaporization is considered one of the most sustainable ways to solve water scarcity. The design of highly efficient solar absorber systems has received extensive attention. Here, we report a novel light absorption material for water evaporation using laser-treated wood. The obtained laser-treated wood possesses interconnected 3D porous networks formed by the random construction of carbon arrays and a hydrophilic surface due to the oxygen implantation by laser treatment. When under 1 sun solar-simulated light irradiation (1 kW m

In the past few years, graphene-based nanocomposites are a hot topic in the fields of materials and chemistry owing to their unique features. We describe a facile melt blending method for preparing polypropylene/graphene nanocomposites in this article. The first stage involved grafting graphene onto chlorinated PP using the Friedel-Crafts reaction. The second stage involved the use of the resulting PP grafted graphene (PPG) as fillers in a melt blend with commercial PP. After being grafted with an organic PP chain, graphene becomes lipophilic; consequently, the PPG can be dispersed well within the PP matrix while retaining excellent interface adhesion. As a result, the thermostability, mechanical performance, and electrical conductivity of PP were significantly improved through the addition of PPG fillers. Additionally, with 10 wt% of PPG fillers (equivalent to 5 wt% graphenes), the conductivity approaches 6.8 Sm-1. As a result of this research, a new method for producing high-performance PP has been developed.

This paper aims to research the high-temperature oxidation behavior of TiC/Mo composite. Adding 5 wt.% TiC, Mo-based composite was prepared by Spark Plasma Sintering. The composite was oxidized at different temperatures (400°C, 600°C, 800°C, 1000°C and 1200°C) and times (5 min, 10 min, 20 min, 30 min and 60 min). When oxidation was at 400-1000°C for 20 minutes, the degree of oxidation intensifies with the increase of temperature, and TiO2 was observed at 1000°C. While the temperature was 1200°C, the oxidation rate gradually decreased with the increase of time. The result shows that the formation of TiO2 can inhibit the oxidation process.

In this study, the two types of high-strength low-alloy steels were melted and cast in a vacuum induction furnace. Phase transition temperature of HSLA steel was calculated by JMatPro software. The calculation results show that the two different types of HSLA steels which have equal phase proportions of ferrite and austenite at a temperature of approximately 820 and 800 °C in HSLA-I and HSLA-II, respectively. In addition, the effect of chemical composition on the microstructure and mechanical properties of steels were studied. The results indicate that the ultimate tensile stress value of HSLA-II samples was greater than the HSLA-I samples by about 35%, and the yield stress and breaking strength value of HSLA-II were higher than HSLA-I as well.

In this research, thermally conductive polyamide 6/hexagonal boron nitride (PA6/hBN) nanocomposites waaere fabricated via an in-situ ring-opening polymerization of e-caprolactam. The hBN filler was exfoliated through a co-solvent exfoliation process and then chemically modified to form an e-caprolactam-grafted BN (cBN). After that, PA6 was introduced onto the cBN surface using a grafting from method. The thermal conductivities of the PA6/cBN composites significantly increased up to 180 % when the BN content was 16.5 wt%. The tensile strength and Young’s modulus of the PA6/cBN composites with 16.5 wt% hBN increased by 30 % and 92 %, respectively, compared to the pristine PA6. The grafted PA6 on BN composites exhibited strong polymer-filler interfacial interactions. Overall, this study provides a facile method of fabricating high-performance PA6 with improved thermal and mechanical properties and higher thermal conductivity.

Resistive random access memory (RRAM) devices with analog resistive switching are expected to be beneficial for neuromorphic applications, and consecutive voltage sweeps or pulses can be applied to change the device conductance and behave synaptic characteristics. In this paper, RRAM devices with a reverse stacking order of 6-nm-thick HfO x and 2-nm-thick AlO x dielectric films were fabricated. The device with TiN/Ti/AlO x /HfO x /TiN stacked layers exhibited digital resistive switching, while the other device with TiN/Ti/HfO x /AlO x /TiN stacked layers could demonstrate synaptic characteristics that were analog set and reset processes under consecutive positive and negative voltage sweeps or a train of potentiation and depression pulses. Moreover, this device could also implement synaptic learning rules, spike-timing-dependent plasticity (STDP). Varying temperature measurements and linear fittings of the measured data were conducted to analyze current conduction mechanisms. As a result, the variation of resistive switching behavior between these two devices is attributed to the varying effectiveness of the oxygen scavenging ability of the Ti layer when put into contact with either AlO x or HfO x . Moreover, AlO x functioned as a diffusion limiting layer (DLL) in the device with TiN/Ti/HfO x /AlO x /TiN stacked layers, and gradual modulation of the production and annihilation of oxygen vacancies is the cause of synaptic characteristics.

Resistive random access memory (RRAM) devices with analog resistive switching are expected to be beneficial for neuromorphic applications, and consecutive voltage sweeps or pulses can be applied to change the device conductance and behave synaptic characteristics. In this paper, RRAM devices with a reverse stacking order of 6-nm-thick HfOx and 2-nm-thick AlOx dielectric films were fabricated. The device with TiN/Ti/AlOx/HfOx/TiN stacked layers exhibited digital resistive switching, while the other device with TiN/Ti/HfOx/AlOx/TiN stacked layers could demonstrate synaptic characteristics that were analog set and reset processes under consecutive positive and negative voltage sweeps or a train of potentiation and depression pulses. Moreover, this device could also implement synaptic learning rules, spike-timing-dependent plasticity (STDP). Varying temperature measurements and linear fittings of the measured data were conducted to analyze current conduction mechanisms. As a result, the variation of resistive switching behavior between these two devices is attributed to the varying effectiveness of the oxygen scavenging ability of the Ti layer when put into contact with either AlOx or HfOx. Moreover, AlOx functioned as a diffusion limiting layer (DLL) in the device with TiN/Ti/HfOx/AlOx/TiN stacked layers, and gradual modulation of the production and annihilation of oxygen vacancies is the cause of synaptic characteristics.

In the scope of refractory material processed by spark plasma sintering development for structural applications in the core of future combustion chamber, Mo-TiC alloys and Mo-TiC-Cr alloys were sintered at 1700°C with a pressure of 30 MPa. Powders of Mo, TiC and Cr were prepared by planetary ball mill in an argon atmosphere. In this dissertation, the structure, element and phase composition of alloys were investigated. The Mo-TiC alloys showed obvious intergranular brittle fracture. The fracture mode of Mo-TiC-Cr alloys, however, was changed to mixed intergranular and transgranular fracture. The obtained results demonstrated that, compared with the peaks of Mo and Mo2C from Mo-TiC, the peaks of Mo and Mo2C from Mo-TiC-Cr were deflected to the right, due to the addition of chromium forming a solid solution. The results of isothermal oxidation tests at 1200°C in air revealed that the chromium compound on the surface of the oxide layer increases and the pores decreases with the increase of oxidation time for Mo-TiC-Cr alloys. The pores of surface of the Mo-TiC alloys were less and smaller than the Mo-TiC-Cr.

Effects of alloying elements (i.e., variable content of Mo and C) on the microstructure and compression properties of four types of experimental material based on TiAl-based alloy containing 8 at.% Nb were investigated. The specimens were prepared by vacuum noncollapsable melting technology and followed by a homogenization treatment with air cooling. The compression properties at room and at elevated temperature were evaluated in laboratory air. The results demonstrate that the inter-lamellar space of the alloy decreased with the addition of the Cr and Mo alloying elements. Cr acts a better role in grain refinement, while Mo enhances the content of γ phase in the alloys. The addition of Cr/Mo elements improves the elastic modulus of the material, but reduces the breaking strength due to the absence of the dislocation region found in non-Cr / Mo alloys that resist cracking. The concentrated distribution of γ phase at grain boundaries hinders recrystallization and the tendency of grain orientation.

Superior electrically conductive PE nanocomposites were prepared with reduced graphene oxide(rGO)-supported MAO cocatalyst via in situ ethylene polymerization. The electrical conductivity of the composites was very high at 1.2 S/m. This value is the highest among reported rGO-filled composites. The cocatalyst system was prepared by modifying with alkoxysilane compound to prevent restacking of the GO plane in the reduction process and solvothermal reduction of GO. The effect of cocatalysts on the properties of nanocomposites and distribution of nanosheets in the polymer matrix was investigated in detail. The mechanical properties and thermal stability of PE/rGO nanocomposites were significantly increased via the addition of a small amount of rGO. These properties resulted from the restacked rGO layers exfoliated in situ by the ethylene insertion between the intercalated layers.

In this paper, the problem of delay dependent robust stability for a class of interval time-varying delay systems with nonlinear perturbations is studied. Based on the idea of delay-partitioning method (DPM), the whole delay interval is divided into two unequal subintervals at appropriate point and a new Lyapunov-Krasovskii functional (LKF) which contains some quadruple-integral terms and augment terms is introduced on each interval. Then, a new bounding technique based on a novel integral inequality approach together with reciprocally convex combination technique is used to deal with the cross term of the derivative. Hence, an enhanced delay-dependent stability criterion is derived in terms of linear matrix inequality (LMI). Finally, the numerical simulation results show that the proposed method is effective and less conservative.

The present study shows that magnesium and aluminium light alloys have been widely utilised in lightweight automotive applications, which is an important future research direction of energy conservation and environmental protection for automobile. In this study, Mg/Al bimetallic composite consisting of AZ91D magnesium alloy and ZL105 alumina alloy was fabricated by compound casting. The results prove that Mg/Al bimetallic composites can be successfully fabricated by liquid–solid compound casting. The structure of interfacial transition zone is made up of three different zones, i.e. Al-side transition zone, interfacial intermediate zone and Mg-side transition zone and α-Al, γ-Al3Mg2, β-Al12Mg17, Mg2Si and δ-Mg are the main specific composition of these zones. Bending strengths of pouring temperature from 620 to 700°C are different, while the maximal bending strength is 23·06 MPa under pouring temperature of 680°C.

This investigation reports a novel room-temperature camphene-based freeze-casting method to prepare aligned and porous alumina ceramics. The ceramic/camphene/dispersant mixed slurries were solidified using a fast room-temperature cooling installation to form excessively overgrown camphene dendrites. The experimental results revealed that camphene-based freeze casting could lead to formation of an aligned and porous structure through room-temperature cooling in a copper die. As the ceramic solid loading increased from 8 to 20 vol.-%, the total porosity of the sintered porous alumina ceramics ranged from 80·5 to 67·5% and the compressive strength increased from 5·8 to 23·5 MPa. This freeze-cast processing is considered potentially useful in fabricating novel porous ceramics with special structure.

A facile coagglomeration method for preparing a long alkyl chain modified graphene oxide (MGO)/MgCl2-supported Ti-based Ziegler-Natta catalyst was reported. The effects of MGO on the catalyst morphology and activity for ethylene polymerization were examined. The resultant polyethylene (PE)/MGO nanocomposites exhibited a layered morphology, with the MGO fillers being well dispersed and exhibiting strong interfacial adhesion to the PE matrix. The thermal stability and mechanical properties of the PE were significantly enhanced with the introduction of a small amount of the MGO filler. Thus, this work provides a facile approach to the production of high-performance PE.

In this article, the issue of robust stability analysis for a sort of uncertain neutral system with mixed time-varying delays is studied. A new Lyapunov–Krasovskii functional comprising quadruple-integral term is introduced so as to develop a less conservative stability condition. A novel discrete and neutral delay-dependent stability criterion based on linear matrix inequalities is given using delay-central point method as well as reciprocally convex combination approach, which is derived by integral inequality approach. Compared with the existing literature, this criterion can greatly reduce the complexity of theoretical derivation and computation. Finally, three numerical comparative examples are designated to verify the superiority of the proposed approach in reducing the conservation of conclusion.

According to the characteristics of laser active imaging and the real-time image features needed, a new image de-noising algorithm based on the voting median filter and integer lifting-wavelet transform was proposed. Firstly, the noise image was dealt with voting median filter to eliminate the interference of impulse noise. Secondly, the noise image was decomposed with lifting-wavelet, wavelet coefficients was processed with Bayes adaptive threshold method. Finally got de-noised image by inverse transform. Through compared with the standard median filter, lifting-wavelet transform, the ordinary wavelet combined with the median filter, experimental results show that this method has advanced de-noising performance and edge retention. Meanwhile it has the less computation time.

Modulating the water pulse time during thermal atomic layer deposition is an effective approach to enhancing the ferroelectric properties of undoped HfO2 thin films. Through grazing incidence X-ray diffraction (GI-XRD), it was observed that a shorter water pulse time can inhibit formation of the monoclinic phase and thereby obtain good remanent polarization. Transmission electron microscopy (TEM) images and GIXRD analysis were used to reveal the crystallization conditions of the undoped HfO2 thin films. By modulating the water pulse time during deposition of all samples, no impurities were found in these films via X-ray photoelectron spectroscopy. Moreover, samples with shorter water pulse times revealed lower binding energy and higher leakage current. However, electric measurement results of samples with shorter water pulse times revealed a higher remanent polarization of approximately 9 μC cm−2 and a coercive field of ~1.95 MV cm−1 compared with other samples. After endurance testing, the films lasted for more than 108 cycles at 2.25 V, so they are ideally suited to low-power ferroelectric CMOS devices and non-volatile memory applications.

In this paper, we consider the problem of robust delay-dependent stability for a class of linear uncertain systems with interval time-varying delay. By using the directly Lyapunov-Krasovskii (L-K) functional method, integral inequality approach and the free weighting matrix technique, new less conservative stability criteria for the system is formulated in terms of linear matrix inequalities .Numerical examples are given to show the effectiveness of the proposed approach.

Copolymerization of St and St-POSS with and without 4-MeSt was carried out with half-titanocenes of Cp*TiCl3 catalyst and MMAO cocatalyst. The activity of catalyst and St-POSS content increased by the addition of 4-MeSt as the 3 rd monomer. The characteristic crystalline peak of St/St-POSS copolymer was altered by incorporating of 4-MeSt. With increasing 4-MeSt contents, the glass transition temperature of the polymers increased and the thermal stability was improved. The molecular weight and PDI of the polymers were not changed significantly with the incorporation of 4-MeSt.

Nanoporous silica-based aerogels with additive of K2Ti6O13 whisker were successfully synthesized by an ambient pressure drying method. After aging and washing of wet gel, surface modification with cyclohexane was followed to replace the solvent with the pores of wet gel to reduce the surface tension during ambient drying. The microstructure and physicochemical properties of the SiO2–K2Ti6O13 aerogels were characterized by SEM, TEM, FTIR, TG-DTA and XRD. Their specific surface was in the range of 785–1210 m2/g and their average pore size was between 10 and 20 nm. The transparency of the as-dried aerogels was enhanced as K2Ti6O13 whisker was increased and the transmittance of the heat-treated aerogels was slightly decreased with increasing heat-treatment temperature.

Hydrophobic silica-based aerogels with different nano-TiO 2 additive were successfully synthesized by an ambient pressure drying method. After aging and washing of wet gel, surface modification with cyclohexane was followed to replace the solvent with the pores of wet gel to reduce the surface tension during ambient drying. The synthesized SiO 2 –TiO 2 aerogels thermally treated at 350 °C were light and crack-free, and the density was 0.125–0.138 g/cm 3 . The microstructure and physical characteristic of the SiO 2 –TiO 2 aerogels were characterized by FTIR, SEM, EDS and BET. Their specific surface was in the range of 785–1210 m 2 /g and their average pore size was between 30 and 45 nm. Nano-TiO 2 powders are physically embedded by SiO 2 aerogel, and there is an obvious Ti–O–Ti and Si–O–Si bonding group based on structural analysis.

Porous TiB2 ceramics with a three-dimensional interconnected skeleton were fabricated by high temperature pressureless sintering from fine TiB2 powders. The microstructure of the porous TiB2 ceramic was characterized by the enhanced neck growth between the initially touching particles. This neck growth was ascribed to the selective heating of TiB2 particles with different dimension. The porous structure prepared by the high-temperature sintering exhibited higher bending strength and fracture toughness in the present experiment. The improved mechanical properties of the sintered composites were attributable to the enhanced neck growth by surface diffusion.

The recrystallized carbon-ceramic composites were prepared from calcined coke, coal-tar pitch and Cr by hot-press to investigate the effects of Cr on the physical properties, mechanical properties and microstructure of recrystallized graphite. Experimental results showed that Cr doped recrystallized graphites exhibited higher bending strength and compressive strength and lower electrical resistivity when the Cr content is10wt% compared with pure graphite. Microstructural analyses revealed that the degree of graphitization of recrystallized graphite increased and the layers spacing of microcrystalline decreased with increasing the Cr concentration. XRD analysis indicated that Cr added to the carbon substrate was in the form of C, Cr2C3 and Cr2O3. The catalytic mechanism of Cr dopant to accelerate the graphitization of carbon substrates can be explained by the mechanism of decomposition of the carbide.

Low density SiO2-xZrO2 aerogels with x=35wt%, 65wt%, 75wt%, 90wt%, 95wt% were prepared by CO2 supercritical drying technique with tetraethylorthosilicate (TEOS) and zirconyl nitrate dihydrate (ZrO(NO3)2 .2H2O) by hydrolytic polycondensation under different chemical conditions. The prepared aerogels are performed by X-ray Diffraction (XRD), Transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FT-IR) and BET surface areas to characterize and analyze the morphology and pore structure of SiO2-ZrO2 aerogels. The results showed that the SiO2-ZrO2 areogels are the typical of nano mesopores and the average pore size is about 50 nm. The specific surface areas varied from 345.5 to 615.5 m2/g with (SBET)MAX = 615.5 m2/g with 20wt% Zirconia; Moreover a mass of Si-O-Zr bands formed in the aerogels and the formation mechanism of Si-O-Zr bands are also discussed.

Highly Nano-porous SiO2-ZrO2 aerogels were manufactured with tetraethylorthosilicate (TEOS) and zirconyl nitrate dihydrate (ZrO(NO3)2 .5H2O) by the sol-gel method followed by supercritical drying technique. The prepared aerogels are performed by SEM, FT-IR and BET to characterize and analyze the morphology and pore structure of SiO2-ZrO2 aerogels. The results showed that:(i) The areogels are the typical of nano pores in the interval between 1

Model-based event-triggered state feedback control method can significantly reduce communication in networked control systems. Based on the exactly investigates the disturbance impact on event triggering, we found that the event triggering in model-based event-triggered state feedback control is sensitive to the varying degree of disturbances but not the magnitude of disturbances. In this paper, some new results are given about model-based event-triggered control, these results also verified by simulation.

A novel well-defined amphiphilic Core-Shell star-block copolymer was synthesized from trimethylolpropane, ε-caprolactone, and glycidyl methacrylate by a combination of enzymatic ring-opening polymerization and atom transfer radical polymerization. The structure and molecular weight of the macroinitiator and the star-block copolymer were confirmed by means of nuclear magnetic resonance and gel permeation chromatography. The effects of the glycidyl methacrylate sequence length on the hydrodynamic diameter and morphology of the polymer micelles were investigated by dynamic light scattering and transmission electron microscopy, respectively.