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Titania-doped methyl-modified silica membrane was prepared via an acid-catalyzed sol-gel method using tetraethylorthosilicate and methyltriethoxysilane as the silicon source and tetraethylorthosili...

Cobalt-doped silica organic-inorganic (Co/SiO2) materials were prepared by sol-gel technique using tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as silicon precursors and Co(NO3)2...

Novel AgBr/TiO2/(I/S) composite was synthesized by deposition–precipitation method. The AgBr/TiO2/(I/S) composite was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, UV–Vis diffuse reflectance spectra and the N2 adsorption/desorption instrument. Under visible light irradiation, AgBr/TiO2/(I/S) composite displayed much higher photocatalytic activity than that of pure I/S in the degradation of Rhodamine B (RhB). The RhB dye was degraded by 89% in less than 100 min. All results indicated that AgBr/TiO2/(I/S) composite have good photocatalytic activity and chemical stability. Moreover, ·O2− is demonstrated to be the dominant radical for the photocatalytic degradation of RhB.

An experimental investigation and dynamic simulation of vertical falling-film LiBr/H2O absorption heat transformer systems have been reported in this paper. The established 20 kW experimental equipment was used to test the dynamic performance and verified the mathematical model. The experimental results show that there is a time delay between the input heat and output useful heat, and the time delay of the experimental results is 115 s. The simulated results show that the response time increases with increasing total solution mass and increases with decreasing solution mass flow rate. The temperature flow oscillations decrease with increasing total solution mass and decrease when the solution mass flow rate decreases. The response time of the absorption heat transformer is almost linearly related to the characteristic time of solution storage, which provides guidance for the operation and prediction. By adjusting the total solution mass and solution mass flow rate, theoretically the response time can be reduced to approximately 150 s. The temperature change range of the absorber outlet water can be controlled within 0.5 K by reducing the solution mass flow rate. The total solution mass and mass flow rate should be reduced, which can reduce temperature flow oscillations and shorten the time delay. The response time can be predicted by combining the experimental data and the linear relationship of the response time for any absorption heat transformer.

g-C3N4 is a well-known visible-light-active photocatalyst for the degradation of environmental pollutants. However, its photocatalytic activity is restricted by the small specific surface area and the e−/h+ recombination rate. In order to improve the photocatalytic performance of g-C3N4, AgBr/g-C3N4 composite photocatalyst has been designed. The as-prepared AgBr/g-C3N4 was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible spectrophotometer (UV–Vis) and room temperature photoluminescence (PL). The photocatalytic activity was evaluated by the photodegradation of methyl orange (MO) under simulated visible-light irradiation. The results show that g-C3N4 is porous structure with a large specific surface area of loading AgBr nanoparticles greatly improves the photocatalytic activity. The AgBr content is optimized to 25 wt%, where the degradation rate of MO can reach 90% after 30 min. The enhancement in photocatalytic performances is mainly attributed to the effective production and transfer of e−/h+ for AgBr can absorb the visible light. Moreover, ·O2− is demonstrated to be the dominant radical for the photocatalytic degradation of MO.

g-C3N4 with porous structure has been synthesized by a thermal polymerization method and its specific surface area regulated by changing the calcination temperature. The as-prepared g-C3N4 was characterized by x-ray diffraction (XRD) analysis, Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), and ultraviolet–visible (UV–Vis) spectrophotometer. The photocatalytic activity of g-C3N4 was investigated using Methyl Orange (MO) as target pollutant. The results show that the g-C3N4 exhibited a unique porous structure with a specific surface area reaching 142.1 m2/g at 610°C. When the calcination temperature was 570°C, the specific surface area of g-C3N4 was 116.3 m2/g and the photodegradation rate of MO was 65%. Moreover, g-C3N4 retained good photocatalytic stability after being used for five times. The photocatalytic mechanism was also explored by free-radical scavenging experiments.

Two methyl-modified Al2O3/SiO2 xerogels, i. e. AIP-Al2O3/MSiO2 and ANN-Al2O3/MSiO2 xerogels, were prepared using aluminum isopropoxide and aluminum nitrate nonahydrate as the aluminum precursors, respectively. The appearance, density, viscosity, Gibbs activation energy for viscous flow and reaction rate constant of the sols were analyzed and compared. Their microstructures were characterized by means of powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and nitrogen adsorption–desorption measurements. The results show that the Al–O–Si bond is formed in the AIP-Al2O3/MSiO2 and ANN-Al2O3/MSiO2 xerogels. The ANN-Al2O3/MSiO2 sol has a smaller mean particle size and greater sol stability than the AIP-Al2O3/MSiO2 sol. Meanwhile, the ANN-Al2O3/MSiO2 xerogel has a smaller pore size and higher porosity. The total pore volume and specific surface area of the ANN-Al2O3/MSiO2 xerogel are 27.27% and 29.36% larger than those of the AIP-Al2O3/ MSiO2 sample, respectively. The saturated adsorption capacity of the ANN-Al2O3/MSiO2 xerogel to methylene blue is 7.15% larger than that of the AIP-Al2O3/MSiO2 xerogel.

With methyltriethoxysilane as hydrophobic precursors and aluminum isopropoxide as the aluminum source, the Al2O3/SiO2 sols and their gel materials were prepared. The effects of aluminum content (nA...

Titanium dioxide (TiO2) sol was prepared using tetrabutyl titanate as a precursor via an acid catalyzed sol-gel process. Investigation of the effects of acid content and annealing on the properties...

Vibration energy exists widely in nature, and the use of intelligent materials to harvest vibration energy to power microelectronic systems is a trend in the field of new energy. In this paper, the inverse effect of magnetic shape memory alloy (MSMA) that is a new intelligent material, is used to design a new kind of vibration energy harvester, which is based on integrated cantilever beam. The structure of cantilever beam and magnetic field loop are optimized, and the ideal structure model of vibration energy harvester is established. The magnetic field is analyzed by using ANSYS finite element software. On the basis of developing the prototype of the harvester, the experimental platform is built and the harvester is tested. The results show that the output voltage of the MSMA vibration energy harvester based on cantilever beam can reach more than 300 mV, which has a wide frequency band of vibration energy harvesting, and possesses a good prospect for development and application.

Purpose The purpose of this paper is to develop a novel method for analyzing wheel-rail (W-R) contact using thermo-mechanical measurements and study the effects of heating on the characteristics of W-R contact under different creepages. Design/methodology/approach This study developed an implicit-explicit finite element (FE) model which could solve both partial slip and full sliding problems by setting different angular velocities on the wheels. Based on the model, four material types under six different creepages were simulated. Findings The results showed that frictional heating significantly affected the residual stress distribution under large creepage conditions. As creepage increased, the temperature of the wheel tread and rail head rose and the peak value was located at the trailing edge of the contact patch. Originality/value The proposed FE model could reduce computational time and thus cost to about one-third of the amount commonly found in previous literature. Compared to other studies, these results are in good agreement and offer a reasonable alternative method for analyzing W-R contact under various conditions. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0298

We propose a multi-functional device by using the solid-state plasma, which can be called a plasma metamaterial absorber (PMA). The absorber can get tunable absorption spectrum by exciting different solid-state plasma resonance units. The common absorption frequency region of TE and TM waves can span from 1.7162 to 3.997 THz, whose absorption rate is is than 90%. The simulations also demonstrate that when the excited solid-state plasma resonance units are different, different operating states can be realized. The proposed PMA not only can be seen as an absorber but also can be considered as a reflector or a polarization splitter under different operating states. Moreover, by investigating the surface current, electric field, and energy loss, the physical mechanism of absorption of this PMA can be figured out, which is the magnetic resonance. Such a device also can potentially act as a space beam compiler.

Austenitic stainless steels are widely used in the key components of major equipment and the welds can be the weakest parts of equipment made with these materials. Ultrasonic waves propagate in austenitic stainless steel welds with multiple paths and modes. This study employed a multi-view total focusing method using an ultrasonic phased array for defect detection in the welds of small-diameter austenitic stainless steel pipes. The detection capability of four different direct wave modes and eight different half-skip wave modes for typical defects were compared and analysed through numerical simulation. A fusion imaging method was developed using the preferred direct and half-skip wave modes. The process was further verified with a weld defect detection experiment carried out on small-diameter austenitic stainless steel pipes. The results show that the multi-view total focusing method can efficiently detect the defects in the welds of small-diameter tubes. Compared with the single-mode imaging method, the fusion total focusing imaging approach can not only improve the signal-to-noise ratio but can also reduce the number of image artefacts.

The effects of La and La+Sc addition on mechanical properties and thermal conductivity of Al-4.8Cu alloy were comprehensively studied. The as-cast samples were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and first-principles methods. The results reveal that the grain morphology of Al-4.8Cu alloy changes from dendrite to fine equiaxed grain with La, La+Sc addition. The average grain size of Al-Cu-La (Al-4.8Cu-0.4La) and Al-Cu-La-Sc (Al-4.8Cu-0.4La-0.4Sc) decreased by 37.2% (70.36 μm) and 63.3% (119.64 μm) respectively compared with Al-Cu (Al-4.8Cu). Al-Cu-La has the highest elongation among the three which is 34.4% (2.65%) higher than Al-Cu. Al-Cu-La-Sc has the highest ultimate tensile strength and yield strength which are 55.1% (80.9 MPa) and 65.2% (62.1 MPa) higher than Al-Cu, respectively. The thermal conductivity of Al-Cu-La and Al-Cu-La-Sc is 10.0% (18.797 W·m−1·k−1) and 6.5% (12.178 W·m−1·k−1) higher than Al-Cu alloy respectively. Compared with Al-Cu, Al-Cu-La has less shrinkage and porosity, the presence of Al4La and AlCu3 contribute a lot to the decrease of specific heat capacity and the increase of plasticity and toughness. The porosity of Al-Cu-La-Sc does not significantly decrease compared with Al-Cu-La, the presence of Al3Sc and AlCuSc bring about the increase of specific heat capacity and brittleness.

The study presents the synthesis of TiO2/SiO2 membrane materials using sol–gel method by hydrolysis of tetrabutyl titanate (TBOT) with ethanol and water mixture as titania source, tetraethy...

Titanium dioxide (TiO2) sol was prepared using tetrabutyl titanate as a precursor via an acid catalyzed sol–gel process. The influence of water content on the sol density, viscosity, stability and ...

A series of Al2O3 sols were prepared by HNO3 catalysis of aluminum isopropoxide (AIP), using different molar ratios of HNO3/AIP (nH). The changes in sol densities, viscosities, refractive i...

Nickel-doped silica organic–inorganic hybrid (Ni/SiO2) membranes based on tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) were prepared via a sol–gel process for H2/CO2 separation. The influence of calcination temperature and Ni-doping amount on the microstructure and surface free energy of Ni/SiO2 materials was investigated. The permeance of H2 and CO2 and vapor stability of the membranes were tested. For the Ni/SiO2 membrane, the optimal calcination temperature should be 350 °C and Ni/TEOS molar ratio is 0.1. After calcination at 350 °C, nickel element exists in form of Ni–O–Si structure and crystalline NiO with small grain size. At this temperature, the water contact angle of Ni/SiO2 film achieved a maximum of (96.1±0.4)° and the surface free energy reached the minimum. The H2 and CO2 permeance of freshly-prepared the Ni/SiO2 membrane was 7.86×10−6 and 1.50×10−6 mol m−2 Pa−1 s−1, respectively, at 25 °C and a pressure difference of 0.4 MPa. Compared with the pure SiO2 membrane, the H2 permeance and H2/CO2 selectivity of Ni/SiO2 membrane increased by 20.9% and 15.9%, respectively. After aging in the moist condition for 7 d, the H2 permeance of Ni/SiO2 membrane was reduced by 6.9% and the H2/CO2 selectivity increased by 4.7%. The Ni/SiO2 membrane showed higher H2 permeance, H2/CO2 selectivity and vapor stability than pure SiO2 membrane.

A novel Pd/SiO2 inorganic–organic composite material was developed for the selective separation of H2 from a mixture of H2 and CO2. Its thermal stability and microstructure calcined under N2 atmosphere were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and N2 sorption–desorption measurements. Pd element in Pd/SiO2 gel material exists in PdCl2 form, calcination at 350 °C can result in the complete transformation of Pd2+ to metallic Pd0. With the increase of calcination temperature, the hydrophobic Si–CH3 bands decreased in intensity. The residue of Pd/SiO2 material calcined at 800 °C was mainly composed of Si–O–Si, metallic Pd0, CSi4 and some elemental C0. The mean pore size, BET specific surface area and total pore volume of the as-prepared Pd/SiO2 material calcined at 350 °C was about 2.26 nm, 417.35 m2 g−1 and 0.288 m3 g−1, respectively. The mean H2 and CO2 permeances of the corresponding Pd/SiO2 membrane were 9.90×10−6 and 9.10×10−7 mol m−2 Pa−1 s−1, respectively, when operating at 200 °C and a pressure difference of 0.3 MPa. After the steam exposure at 200 °C for 168 h, the H2 permeance decreased by 3.23% while the H2/CO2 permselectivity increased by 2.50%.

In the present work, zirconium nitrate pentahydrate (Zr(NO3)4·5H2O) was used as ZrO2 precursors. The ZrO2-SiO2 sols with the Zr/TEOS molar ratios (nZr) ranging from 0 to 2.0 were synthesized by two...

The AgNbO3 antiferroelectric (AFE) ceramics have attracted increasing attention for their high energy storage performance and environmentally friendly characters. In this work, Ag1–2xBaxNbO3 ceramics were successfully prepared by the conventional solid-state reaction method. The effect of Ba-modification on phase structure, microstructure, and electric properties was systematically investigated. The introduction of Ba2+ ion led to complex cell parameter evolution and significant refinement of grain size. Room temperature dielectric permittivity increased obviously from ~260 for the pure AgNbO3 counterpart to ~350 for those after adding a small amount of Ba element. Slim P-E hysteresis loops with improved AFE phase were achieved after Ba modification, due to the decrease of tolerance factor. A high recoverable energy density up to 2.3 J/cm3 with energy efficiency of 46% can be obtained for the composition of Ag0.96Ba0.02NbO3, in correlation with the enhanced AFE stability, reduced Pr, increased Pm and decreased ΔE. Moreover, the Ag0.96Ba0.02NbO3 ceramics also exhibited excellent temperature stability in both energy density and efficiency with small variation of

The application of lithium-sulfur batteries is limited due to low electric conductivity of sulfur and “shuttle effect” caused by diffusion of soluble polysulfides to the anode. In this study, self-made mesoporous TiO2 and commercial Ketjen Black are mixed to obtain a composite material, which is then coated on glass fiber membrane through a slurry method. The modified glass fiber membrane is used as a functional separator in lithium-sulfur battery. The batteries using modified separator show a high initial discharge specific capacity of 1130.3mAh g−1 at 0.2C and an excellent cycling stability of 991.8mAh g−1 even after 60 cycles, and initial discharge specific capacity of 996.7mAh g−1 at 0.5C and 804.3mAh g−1 even after 100 cycles. The improved performance of the battery can be ascribed to effective adsorption of mesoporous TiO2 to the soluble polysulfides and limit diffusion of the reaction intermediate to anode side. Moreover, the excellent electrical conductivity of Ketjen Black coated on the surface of glass fiber membrane can reduce the internal resistance, activate the absorbed polysulfides, and increase the specific capacity of the lithium-sulfur battery. It is believed that mesoporous TiO2 and Ketjen Black modified glass fiber membrane effectively suppresses the “shuttle effect” during the cycling and provides a promising approach for high-performance lithium-sulfur batteries.

In this paper, a polarization-insensitive broadband terahertz absorber (PBTA) is presented and demonstrated, which can realize a polarization-insensitive, and broadband perfect absorption in the terahertz regime. By simulation, the polarization-insensitive broadband absorption is over 90%, which runs from 4.904 THz to 6.632 THz (the relative bandwidth is 29.96%), and the obtained absorption remains a good absorption performance with a wide incident angle for both TE and TM waves. The surface current distributions, power loss densities, electric and magnetic field distributions of such an absorber are investigated to figure out the physical mechanism of such a PBTA. The effects structure parameters on the absorption performance are also studied, which will be a guiding to realize a PBTA. The simulated results show that the proposed multilayer structure can help to design a PBTA. Keywords: Broadband absorber, Terahertz absorber, Fabry-Perot cavity resonance, Multilayer structure

Transition metal dichalcogenides (TMDs) are a promising non-noble-metal electrocatalyst toward the hydrogen evolution reaction (HER). However, the sluggish HER kinetics and poor electric conductivities of the TMDs severely restrict their practical applications for high-efficient water splitting. Herein, a nanosheet array of 2D anion-tailored MoSexS2–x on carbon nanotubes (CNTs) was prepared through an anionic substitution reaction. The all-solid-state sulfidation of the CNT-MoSe2 precursor using the sulfur powder as the sulfur source indicates a green and easily scalable strategy for the preparation of the CNT-MoSexS2–x hybrid. As a result, the CNT-MoSexS2–x hybrid delivers an excellent HER performance including a low onset overpotential (83 mV), small Tafel slope (40 mV dec–1) and long-term stability (overpotential at 10 mA cm–2 from 160 to 166 mV after 6000 cycles). The superior electrocatalytic activities of the CNT-MoSexS2–x hybrid are originated from decreased hydrogen adsorption energy associated wi...

The polyethyleneimine dithiocarbamate was employed as polymers to synthesize Fe3Pt-Ag nanocomposites by using the seed deposition method. Fe3Pt-Ag nanocomposites were utilized for the catalytic degradation of methyl orange(MO) in the presence of NaBH4. Fe3Pt-Ag nanocomposites showed good chemical catalytic activity and stability in pollutants degradation. Furthermore, Fe3Pt-Ag nanocomposites can keep their efficiency till four cycles. The results suggest that the nanocatalysts with recyclability have broad prospects in environmental conservation applications.

In this paper, we propose a three-dimensional tunable absorber to realize a controllable unidirectional absorption and unidirectional transmission based on the plasma metamaterial, which includes two metamaterial layers that are vertical to each other. Each side of the proposed absorber integrates two split-ring resonators, which are made in the solid-state plasma (SSP). Unidirectional absorption and unidirectional transmission can be achieved when the incident angle of the electromagnetic wave is 30°. Furthermore, the unidirectional absorption and unidirectional transmission can be manipulated through exciting the different SSP resonators and adjusting the positions of the corresponding gaps between the two SSP resonators. In addition, the tunable absorption and transmission spectra can be obtained when the different SSP resonators are excited.

High quality ZnO ceramics are required for transparent conductive oxide (TCO) films. In this work, high dense ZnO ceramics with density of ~ 97.5% were sintered by using Cold Sintering Process (CSP), and various post-heat-treating conditions (different types of atmosphere and temperature) were applied to optimize the microstructure and electrical conductivity. After post-heat-treatment, the crystallinity was improved, the relative density increased to > 99.0%, while the grain size exhibited small variations. The most significant improvements in electrical conductivity were observed for the sample post-heat-treated in Ar atmosphere, with more than four orders of enhancement from 0.0005 S/cm for the as-cold-sintered one to a maximum of 16.4 S/cm after post-heat-treating at 500 °C. Our work demonstrated an effective method for preparing high performance ZnO ceramics at ultralow temperature.

Three-dimensional hierarchically porous carbon (denoted as SA-900) with a microporous, mesoporous and macroporous structure was facilely fabricated via direct carbonization of sodium alginate. SA-900 was fully characterized by N2 adsorption–desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction and Raman spectroscopy to confirm its structure. SA-900 was coated onto a glassy carbon electrode surface to construct an ultrasensitive electrochemical sensing platform (SA-900/GCE). Electrochemical behaviors of hydroquinone (HQ), catechol (CC) and resorcinol (RC) on the SA-900/GCE surface were investigated, and it was found that SA-900 possesses excellent electrocatalytic activity towards them. Experimental conditions including carbonization temperature, pH value, SA-900 concentration, accumulation potential and accumulation time were optimized for quantitative assay. Under optimized conditions, linear ranges for simultaneous determination of HQ, CC and RC are 0.05–1.50 μM, 0.05–1.50 μM and 0.50–15.00 μM, respectively. Detection limits for HQ, CC and RC are calculated to be 0.0183 μM, 0.0303 μM and 0.3193 μM (S/N = 3). The SA-900/GCE based electrochemical sensing platform is applied for determining HQ, CC and RC in lake water samples with satisfactory results.

Five β-diketone based Dy(iii) single-ion magnets (SIMs), [DyIII(TTA)3(AIP)]·0.5CH3CH2OH·0.5H2O (1), [DyIII(TTA)3(APIP)]·2CH3OH·H2O (2), [DyIII(TTA)3(DPP)] (3), [DyIII(TTA)3(BPP)]·0.5CH3CH2OH (4) and [DyIII(TTA)3(AIP)]·1.5H2O (5), were fully synthesized through alteration of their phenanthroline derivates (AIP = 2-(anthracen-9-yl)-1H-imidazo[4,5-f][1,10]phenanthroline, APIP = 2-(4-(anthracen-9-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, DPP = 2,3-diphenylpyrazino[2,3-f][1,10]phenanthroline and BPP = 2,3-bis(2,5-dimethylthiophen-3-yl)pyrazino[2,3-f][1,10]phenanthroline). Magnetic investigations reveal that all the complexes perform as SIMs, with notably different effective barriers of 69.4 K (1), 147.3 K (2), 122.1 K (3) and 234.2 K (4) in zero direct current (dc) field. Complexes of 2 and 4 possess almost twofold higher effective barriers compared to 1 and 3. By analyzing the crystal structures, the distinct magnetic dynamics was found to stem from the variation in intermolecular hydrogen bond interactions and charge delocalization of auxiliary ligands. With the help of ab initio calculations, a change of auxiliary ligand brings about varying intensities of quantum tunnelling magnetization (QTM), which account for the distinguishable magnetic dynamics. With a combination of experimental and theoretical analyses, this work provides a visual and instructive perspective to the understanding of fine tuning auxiliary ligands to design structurally modulated SIMs of mononuclear β-diketone dysprosium(iii) complexes.

The characteristic clogging structures of granular spheres blocking three-dimensional granular flow through hopper outlet are analyzed based on packing structures reconstructed using magnetic resonance imaging techniques. Spheres in clogging structures are arranged in a way with typical features of load-bearing, such as more contacting bonds close to the horizontal plane and more mutually-stabilized contact configurations than packing structures away from the orifice. The requirement of load-bearing inevitably leads to the cooperativity of clogging structures with a correlation length of several particle diameters. This correlation length being comparable with the orifice diameter suggests that a clogging structure is composed of several mutually-stabilized structural motifs to span the orifice perimeter, instead of a collection of independent individual spheres to cover the whole orifice area. Accordingly, we propose a simple geometric model to explain the unexpected linear dependence of the average size of three-dimensional clogging structures on orifice diameter.

A series of concrete samples with high hydrogen content were prepared by pressing process with aluminum hydroxide, boron carbide and aluminate cement as raw materials. the mechanical performance of the shielding material was examined by flexural strength tester and compression strength tester. Thermogravimetric analyzer was used to test the weight loss performance of the shielding material, hydrated cement and Al(OH)3. The thermal stability of the concrete at working temperature were investigated by bake the samples at 210°C for 90 hours and at 300°C for 5 hours. The shielding performance against neutron from 241Am-Be source were examined by neutron penetration tests. The test results show that the mechanical properties of the shielding material decrease with the increase of the content of aluminum hydroxide, the compression strength of the shielding material reached above 10MPa. The decomposition temperature of conc is 220°C, the weight loss curve tends to be plateau after baking at 210°C for 20 hours. Most of the crystal water lost after holding at 300°C for 5 hours, but the dimensions of the samples show no obvious change. The shielding performance of the material against neutron from 241Am-Be source is comparable to that of lead-boron polyethylene.

In this paper, we present and demonstrate a band enhanced tunable ultra-broadband absorber (TUA) based on loading the lump resistors (LRs) and cavity resonance. The absorber’s each cell integrates four split ring-shaped solid state plasma resonators (SSPRs) which are connected by the solid state plasma (SSP) bars separately. The four split ring-shaped SSPRs and external truncated SSP bars are loaded with lump elements, respectively. The entire structure also comprises the dielectric substrate and continuous metallic layer. By simulations, the ultra-broadband absorption goes beyond 90% in the frequency region 11.13–19.81 GHz is realized through loading LRs and cavity resonance. Moreover, the absorber also is polarization-independent for the incident electromagnetic wave. It is remarkable that the absorption bandwidth is further promoted by inserting the air cylinders (ACs). The absorption also is investigated for oblique incidence, which shows that the proposed TUA can work over a wide incident angle. We focus on the distribution of surface current, the electric field, and power loss density to elucidate the physical mechanism. In addition, the tunable spectra can be obtained in such TUA by exciting the different SSPRs.

In this paper, a novel way is proposed to realize a broadband absorber, which is based on the plasma metamaterial with the triangular ring-shaped resonators. Each unit cell of the proposed absorber includes three layers, which are metal layer, dielectric layer, and solid-state plasma (SSP) layer, respectively. The top layer is composed of the truncated SSP triangular ring-shaped resonators and the SSP triangular patches, which are situated the middle of triangular rings. An SSP cylinder also is inserted between the central of each SSP triangular patch and the bottom metal layer. The absorption bandwidth can be covered from 11.76 to 14.43 GHz when the absorption rate is larger than 90%, which also is polarization-independent. In addition, the better performances can be realized under different incident angles. To explain the mechanism of high absorption, the electric field, the surface current distribution, and power loss density at different resonant frequencies are present. Moreover, the tunable absorption can be obtained in the proposed absorber while the performance of the absorber can be improved by exciting the different SSP resonators.

Pd-doped SiO2 organic-inorganic hybrid materials were synthesized using sol-gel technique. The Pd-doped SiO2 samples were calcined at the temperature 350°C for several different time in air atmosph...

The Ag-loaded hydrophobic silica (Ag/M-SiO2) materials were prepared by sol-gel method with tetraethylorthosilicate (TEOS) as precursor and methyltriethoxysilane (MTES) as hydrophobic modifier. Contact angles, X-ray diffraction and X-ray photoelectron spectra were used to characterize the as-prepared Ag/M-SiO2 materials. The antibacterial properties of the Ag/M-SiO2 materials were evaluated against Escherichia coli and Staphylococcus aureus. The results indicated that the appropriate calcination temperature of keeping the hydrophobicity of Ag/M-SiO2 materials is 300∼500°C. Ag element exists in Ag/M-SiO2 materials as the elemental form and hydrophobic Si-CH3 groups have been successfully introduced into the Ag/M-SiO2 materials. The qualitative and quantitative antibacterial experiments showed that the antibacterial activity increased with the increase of silver content. When the molar ratio of Ag/TEOS is increased to 0.10, the Ag/M-SiO2 materials showed good antibacterial dissolution and broad-spec...

Pd-doped methyl-modified SiO2 membrane materials were prepared by sol-gel technique with tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as silicon precursors, PdCl2 as pall...

Engineering heterostructures of transition metal disulfides through low-cost and high-yield methods instead of using conventional deposition techniques still have great challenges. Herein, we present a conveniently operated and low-energy-consumption solution-processed strategy for the preparation of heterostructures of MoSe2 nanosheet array on layered MoS2, among which the two-dimensional MoS2 surface is uniformly covered with high-density arrays of vertically aligned MoSe2. The unique compositional and structural features of the MoS2–MoSe2 heterostructures not only provide more exposed active sites for sequent electrochemical process, but also facilitate the ion transfer due to the open porous space within the nanosheet array serving as well-defined ionic reservoirs. As a proof of concept, the MoS2–MoSe2 heterostructures serve as promising bifunctional electrodes for both energy conversions and storages, which exhibit an active and acid-stable activity for catalyzing the hydrogen evolution reaction, hig...